[mono] Use `unsigned char` when computing UTF8 string hashes (#21633)

[mono-project.git] / mono / metadata / metadata.c

/**
 * \file
 * Routines for accessing the metadata
 *
 * Authors:
 *   Miguel de Icaza (miguel@ximian.com)
 *   Paolo Molaro (lupus@ximian.com)
 *
 * Copyright 2001-2003 Ximian, Inc (http://www.ximian.com)
 * Copyright 2004-2009 Novell, Inc (http://www.novell.com)
 * Licensed under the MIT license. See LICENSE file in the project root for full license information.
 */

#include <config.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <glib.h>
#include "metadata.h"
#include "tabledefs.h"
#include "mono-endian.h"
#include "cil-coff.h"
#include "tokentype.h"
#include "class-internals.h"
#include "metadata-internals.h"
#include "verify-internals.h"
#include "class.h"
#include "marshal.h"
#include "debug-helpers.h"
#include "abi-details.h"
#include "cominterop.h"
#include <mono/metadata/exception-internals.h>
#include <mono/utils/mono-error-internals.h>
#include <mono/utils/mono-memory-model.h>
#include <mono/utils/bsearch.h>
#include <mono/utils/atomic.h>
#include <mono/utils/unlocked.h>
#include <mono/utils/mono-counters.h>

static gint32 img_set_cache_hit, img_set_cache_miss, img_set_count;


/* Auxiliary structure used for caching inflated signatures */
typedef struct {
        MonoMethodSignature *sig;
        MonoGenericContext context;
} MonoInflatedMethodSignature;

static gboolean do_mono_metadata_parse_type (MonoType *type, MonoImage *m, MonoGenericContainer *container, gboolean transient,
                                         const char *ptr, const char **rptr, MonoError *error);

static gboolean do_mono_metadata_type_equal (MonoType *t1, MonoType *t2, gboolean signature_only);
static gboolean mono_metadata_class_equal (MonoClass *c1, MonoClass *c2, gboolean signature_only);
static gboolean mono_metadata_fnptr_equal (MonoMethodSignature *s1, MonoMethodSignature *s2, gboolean signature_only);
static gboolean _mono_metadata_generic_class_equal (const MonoGenericClass *g1, const MonoGenericClass *g2,
                                                    gboolean signature_only);
static void free_generic_inst (MonoGenericInst *ginst);
static void free_generic_class (MonoGenericClass *ginst);
static void free_inflated_method (MonoMethodInflated *method);
static void free_inflated_signature (MonoInflatedMethodSignature *sig);
static void free_aggregate_modifiers (MonoAggregateModContainer *amods);
static void mono_metadata_field_info_full (MonoImage *meta, guint32 index, guint32 *offset, guint32 *rva, MonoMarshalSpec **marshal_spec, gboolean alloc_from_image);

static MonoType* mono_signature_get_params_internal (MonoMethodSignature *sig, gpointer *iter);

/*
 * This enumeration is used to describe the data types in the metadata
 * tables
 */
enum {
        MONO_MT_END,

        /* Sized elements */
        MONO_MT_UINT32,
        MONO_MT_UINT16,
        MONO_MT_UINT8,

        /* Index into Blob heap */
        MONO_MT_BLOB_IDX,

        /* Index into String heap */
        MONO_MT_STRING_IDX,

        /* GUID index */
        MONO_MT_GUID_IDX,

        /* Pointer into a table */
        MONO_MT_TABLE_IDX,

        /* HasConstant:Parent pointer (Param, Field or Property) */
        MONO_MT_CONST_IDX,

        /* HasCustomAttribute index.  Indexes any table except CustomAttribute */
        MONO_MT_HASCAT_IDX,
        
        /* CustomAttributeType encoded index */
        MONO_MT_CAT_IDX,

        /* HasDeclSecurity index: TypeDef Method or Assembly */
        MONO_MT_HASDEC_IDX,

        /* Implementation coded index: File, Export AssemblyRef */
        MONO_MT_IMPL_IDX,

        /* HasFieldMarshal coded index: Field or Param table */
        MONO_MT_HFM_IDX,

        /* MemberForwardedIndex: Field or Method */
        MONO_MT_MF_IDX,

        /* TypeDefOrRef coded index: typedef, typeref, typespec */
        MONO_MT_TDOR_IDX,

        /* MemberRefParent coded index: typeref, moduleref, method, memberref, typesepc, typedef */
        MONO_MT_MRP_IDX,

        /* MethodDefOrRef coded index: Method or Member Ref table */
        MONO_MT_MDOR_IDX,

        /* HasSemantic coded index: Event or Property */
        MONO_MT_HS_IDX,

        /* ResolutionScope coded index: Module, ModuleRef, AssemblytRef, TypeRef */
        MONO_MT_RS_IDX,

        /* CustomDebugInformation parent encoded index */
        MONO_MT_HASCUSTDEBUG_IDX
};

const static unsigned char TableSchemas [] = {
#define ASSEMBLY_SCHEMA_OFFSET 0
        MONO_MT_UINT32,     /* "HashId" }, */
        MONO_MT_UINT16,     /* "Major" },  */
        MONO_MT_UINT16,     /* "Minor" }, */
        MONO_MT_UINT16,     /* "BuildNumber" }, */
        MONO_MT_UINT16,     /* "RevisionNumber" }, */
        MONO_MT_UINT32,     /* "Flags" }, */
        MONO_MT_BLOB_IDX,   /* "PublicKey" }, */
        MONO_MT_STRING_IDX, /* "Name" }, */
        MONO_MT_STRING_IDX, /* "Culture" }, */
        MONO_MT_END,

#define ASSEMBLYOS_SCHEMA_OFFSET ASSEMBLY_SCHEMA_OFFSET + 10
        MONO_MT_UINT32,     /* "OSPlatformID" }, */
        MONO_MT_UINT32,     /* "OSMajor" }, */
        MONO_MT_UINT32,     /* "OSMinor" }, */
        MONO_MT_END,

#define ASSEMBLYPROC_SCHEMA_OFFSET ASSEMBLYOS_SCHEMA_OFFSET + 4
        MONO_MT_UINT32,     /* "Processor" }, */
        MONO_MT_END,

#define ASSEMBLYREF_SCHEMA_OFFSET ASSEMBLYPROC_SCHEMA_OFFSET + 2
        MONO_MT_UINT16,     /* "Major" }, */
        MONO_MT_UINT16,     /* "Minor" }, */
        MONO_MT_UINT16,     /* "Build" }, */
        MONO_MT_UINT16,     /* "Revision" }, */
        MONO_MT_UINT32,     /* "Flags" }, */
        MONO_MT_BLOB_IDX,   /* "PublicKeyOrToken" }, */
        MONO_MT_STRING_IDX, /* "Name" }, */
        MONO_MT_STRING_IDX, /* "Culture" }, */
        MONO_MT_BLOB_IDX,   /* "HashValue" }, */
        MONO_MT_END,

#define ASSEMBLYREFOS_SCHEMA_OFFSET ASSEMBLYREF_SCHEMA_OFFSET + 10
        MONO_MT_UINT32,     /* "OSPlatformID" }, */
        MONO_MT_UINT32,     /* "OSMajorVersion" }, */
        MONO_MT_UINT32,     /* "OSMinorVersion" }, */
        MONO_MT_TABLE_IDX,  /* "AssemblyRef:AssemblyRef" }, */
        MONO_MT_END,

#define ASSEMBLYREFPROC_SCHEMA_OFFSET ASSEMBLYREFOS_SCHEMA_OFFSET + 5
        MONO_MT_UINT32,     /* "Processor" }, */
        MONO_MT_TABLE_IDX,  /* "AssemblyRef:AssemblyRef" }, */
        MONO_MT_END,

#define CLASS_LAYOUT_SCHEMA_OFFSET ASSEMBLYREFPROC_SCHEMA_OFFSET + 3
        MONO_MT_UINT16,     /* "PackingSize" }, */
        MONO_MT_UINT32,     /* "ClassSize" }, */
        MONO_MT_TABLE_IDX,  /* "Parent:TypeDef" }, */
        MONO_MT_END,

#define CONSTANT_SCHEMA_OFFSET CLASS_LAYOUT_SCHEMA_OFFSET + 4
        MONO_MT_UINT8,      /* "Type" }, */
        MONO_MT_UINT8,      /* "PaddingZero" }, */
        MONO_MT_CONST_IDX,  /* "Parent" }, */
        MONO_MT_BLOB_IDX,   /* "Value" }, */
        MONO_MT_END,

#define CUSTOM_ATTR_SCHEMA_OFFSET CONSTANT_SCHEMA_OFFSET + 5
        MONO_MT_HASCAT_IDX, /* "Parent" }, */
        MONO_MT_CAT_IDX,    /* "Type" }, */
        MONO_MT_BLOB_IDX,   /* "Value" }, */
        MONO_MT_END,

#define DECL_SEC_SCHEMA_OFFSET CUSTOM_ATTR_SCHEMA_OFFSET + 4
        MONO_MT_UINT16,     /* "Action" }, */
        MONO_MT_HASDEC_IDX, /* "Parent" }, */
        MONO_MT_BLOB_IDX,   /* "PermissionSet" }, */
        MONO_MT_END,

#define EVENTMAP_SCHEMA_OFFSET DECL_SEC_SCHEMA_OFFSET + 4
        MONO_MT_TABLE_IDX,  /* "Parent:TypeDef" }, */
        MONO_MT_TABLE_IDX,  /* "EventList:Event" }, */
        MONO_MT_END,

#define EVENT_SCHEMA_OFFSET EVENTMAP_SCHEMA_OFFSET + 3
        MONO_MT_UINT16,     /* "EventFlags#EventAttribute" }, */
        MONO_MT_STRING_IDX, /* "Name" }, */
        MONO_MT_TDOR_IDX,  /* "EventType" }, TypeDef or TypeRef or TypeSpec  */
        MONO_MT_END,

#define EVENT_POINTER_SCHEMA_OFFSET EVENT_SCHEMA_OFFSET + 4
        MONO_MT_TABLE_IDX,  /* "Event" }, */
        MONO_MT_END,

#define EXPORTED_TYPE_SCHEMA_OFFSET EVENT_POINTER_SCHEMA_OFFSET + 2
        MONO_MT_UINT32,     /* "Flags" }, */
        MONO_MT_TABLE_IDX,  /* "TypeDefId" }, */
        MONO_MT_STRING_IDX, /* "TypeName" }, */
        MONO_MT_STRING_IDX, /* "TypeNameSpace" }, */
        MONO_MT_IMPL_IDX,   /* "Implementation" }, */
        MONO_MT_END,

#define FIELD_SCHEMA_OFFSET EXPORTED_TYPE_SCHEMA_OFFSET + 6
        MONO_MT_UINT16,     /* "Flags" }, */
        MONO_MT_STRING_IDX, /* "Name" }, */
        MONO_MT_BLOB_IDX,   /* "Signature" }, */
        MONO_MT_END,

#define FIELD_LAYOUT_SCHEMA_OFFSET FIELD_SCHEMA_OFFSET + 4
        MONO_MT_UINT32,     /* "Offset" }, */
        MONO_MT_TABLE_IDX,  /* "Field:Field" }, */
        MONO_MT_END,

#define FIELD_MARSHAL_SCHEMA_OFFSET FIELD_LAYOUT_SCHEMA_OFFSET + 3
        MONO_MT_HFM_IDX,    /* "Parent" }, */
        MONO_MT_BLOB_IDX,   /* "NativeType" }, */
        MONO_MT_END,

#define FIELD_RVA_SCHEMA_OFFSET FIELD_MARSHAL_SCHEMA_OFFSET + 3
        MONO_MT_UINT32,     /* "RVA" }, */
        MONO_MT_TABLE_IDX,  /* "Field:Field" }, */
        MONO_MT_END,

#define FIELD_POINTER_SCHEMA_OFFSET FIELD_RVA_SCHEMA_OFFSET + 3
        MONO_MT_TABLE_IDX,  /* "Field" }, */
        MONO_MT_END,

#define FILE_SCHEMA_OFFSET FIELD_POINTER_SCHEMA_OFFSET + 2
        MONO_MT_UINT32,     /* "Flags" }, */
        MONO_MT_STRING_IDX, /* "Name" }, */
        MONO_MT_BLOB_IDX,   /* "Value" },  */
        MONO_MT_END,

#define IMPLMAP_SCHEMA_OFFSET FILE_SCHEMA_OFFSET + 4
        MONO_MT_UINT16,     /* "MappingFlag" }, */
        MONO_MT_MF_IDX,     /* "MemberForwarded" }, */
        MONO_MT_STRING_IDX, /* "ImportName" }, */
        MONO_MT_TABLE_IDX,  /* "ImportScope:ModuleRef" }, */
        MONO_MT_END,

#define IFACEMAP_SCHEMA_OFFSET IMPLMAP_SCHEMA_OFFSET + 5
        MONO_MT_TABLE_IDX,  /* "Class:TypeDef" },  */
        MONO_MT_TDOR_IDX,  /* "Interface=TypeDefOrRef" }, */
        MONO_MT_END,

#define MANIFEST_SCHEMA_OFFSET IFACEMAP_SCHEMA_OFFSET + 3
        MONO_MT_UINT32,     /* "Offset" }, */
        MONO_MT_UINT32,     /* "Flags" }, */
        MONO_MT_STRING_IDX, /* "Name" }, */
        MONO_MT_IMPL_IDX,   /* "Implementation" }, */
        MONO_MT_END,

#define MEMBERREF_SCHEMA_OFFSET MANIFEST_SCHEMA_OFFSET + 5
        MONO_MT_MRP_IDX,    /* "Class" }, */
        MONO_MT_STRING_IDX, /* "Name" }, */
        MONO_MT_BLOB_IDX,   /* "Signature" }, */
        MONO_MT_END,

#define METHOD_SCHEMA_OFFSET MEMBERREF_SCHEMA_OFFSET + 4
        MONO_MT_UINT32,     /* "RVA" }, */
        MONO_MT_UINT16,     /* "ImplFlags#MethodImplAttributes" }, */
        MONO_MT_UINT16,     /* "Flags#MethodAttribute" }, */
        MONO_MT_STRING_IDX, /* "Name" }, */
        MONO_MT_BLOB_IDX,   /* "Signature" }, */
        MONO_MT_TABLE_IDX,  /* "ParamList:Param" }, */
        MONO_MT_END,

#define METHOD_IMPL_SCHEMA_OFFSET METHOD_SCHEMA_OFFSET + 7
        MONO_MT_TABLE_IDX,  /* "Class:TypeDef" }, */
        MONO_MT_MDOR_IDX,   /* "MethodBody" }, */
        MONO_MT_MDOR_IDX,   /* "MethodDeclaration" }, */
        MONO_MT_END,

#define METHOD_SEMA_SCHEMA_OFFSET METHOD_IMPL_SCHEMA_OFFSET + 4
        MONO_MT_UINT16,     /* "MethodSemantic" }, */
        MONO_MT_TABLE_IDX,  /* "Method:Method" }, */
        MONO_MT_HS_IDX,     /* "Association" }, */
        MONO_MT_END,

#define METHOD_POINTER_SCHEMA_OFFSET METHOD_SEMA_SCHEMA_OFFSET + 4
        MONO_MT_TABLE_IDX,  /* "Method" }, */
        MONO_MT_END,

#define MODULE_SCHEMA_OFFSET METHOD_POINTER_SCHEMA_OFFSET + 2
        MONO_MT_UINT16,     /* "Generation" }, */
        MONO_MT_STRING_IDX, /* "Name" }, */
        MONO_MT_GUID_IDX,   /* "MVID" }, */
        MONO_MT_GUID_IDX,   /* "EncID" }, */
        MONO_MT_GUID_IDX,   /* "EncBaseID" }, */
        MONO_MT_END,

#define MODULEREF_SCHEMA_OFFSET MODULE_SCHEMA_OFFSET + 6
        MONO_MT_STRING_IDX, /* "Name" }, */
        MONO_MT_END,

#define NESTED_CLASS_SCHEMA_OFFSET MODULEREF_SCHEMA_OFFSET + 2
        MONO_MT_TABLE_IDX,  /* "NestedClass:TypeDef" }, */
        MONO_MT_TABLE_IDX,  /* "EnclosingClass:TypeDef" }, */
        MONO_MT_END,

#define PARAM_SCHEMA_OFFSET NESTED_CLASS_SCHEMA_OFFSET + 3
        MONO_MT_UINT16,     /* "Flags" }, */
        MONO_MT_UINT16,     /* "Sequence" }, */
        MONO_MT_STRING_IDX, /* "Name" }, */
        MONO_MT_END,

#define PARAM_POINTER_SCHEMA_OFFSET PARAM_SCHEMA_OFFSET + 4
        MONO_MT_TABLE_IDX,  /* "Param" }, */
        MONO_MT_END,

#define PROPERTY_SCHEMA_OFFSET PARAM_POINTER_SCHEMA_OFFSET + 2
        MONO_MT_UINT16,     /* "Flags" }, */
        MONO_MT_STRING_IDX, /* "Name" }, */
        MONO_MT_BLOB_IDX,   /* "Type" }, */
        MONO_MT_END,

#define PROPERTY_POINTER_SCHEMA_OFFSET PROPERTY_SCHEMA_OFFSET + 4
        MONO_MT_TABLE_IDX, /* "Property" }, */
        MONO_MT_END,

#define PROPERTY_MAP_SCHEMA_OFFSET PROPERTY_POINTER_SCHEMA_OFFSET + 2
        MONO_MT_TABLE_IDX,  /* "Parent:TypeDef" }, */
        MONO_MT_TABLE_IDX,  /* "PropertyList:Property" }, */
        MONO_MT_END,

#define STDALON_SIG_SCHEMA_OFFSET PROPERTY_MAP_SCHEMA_OFFSET + 3
        MONO_MT_BLOB_IDX,   /* "Signature" }, */
        MONO_MT_END,

#define TYPEDEF_SCHEMA_OFFSET STDALON_SIG_SCHEMA_OFFSET + 2
        MONO_MT_UINT32,     /* "Flags" }, */
        MONO_MT_STRING_IDX, /* "Name" }, */
        MONO_MT_STRING_IDX, /* "Namespace" }, */
        MONO_MT_TDOR_IDX,   /* "Extends" }, */
        MONO_MT_TABLE_IDX,  /* "FieldList:Field" }, */
        MONO_MT_TABLE_IDX,  /* "MethodList:Method" }, */
        MONO_MT_END,

#define TYPEREF_SCHEMA_OFFSET TYPEDEF_SCHEMA_OFFSET + 7
        MONO_MT_RS_IDX,     /* "ResolutionScope=ResolutionScope" }, */
        MONO_MT_STRING_IDX, /* "Name" }, */
        MONO_MT_STRING_IDX, /* "Namespace" }, */
        MONO_MT_END,

#define TYPESPEC_SCHEMA_OFFSET TYPEREF_SCHEMA_OFFSET + 4
        MONO_MT_BLOB_IDX,   /* "Signature" }, */
        MONO_MT_END,

#define GENPARAM_SCHEMA_OFFSET TYPESPEC_SCHEMA_OFFSET + 2
        MONO_MT_UINT16,     /* "Number" }, */
        MONO_MT_UINT16,     /* "Flags" }, */
        MONO_MT_TABLE_IDX,  /* "Owner" },  TypeDef or MethodDef */
        MONO_MT_STRING_IDX, /* "Name" }, */
        MONO_MT_END,

#define METHOD_SPEC_SCHEMA_OFFSET GENPARAM_SCHEMA_OFFSET + 5
        MONO_MT_MDOR_IDX,   /* "Method" }, */
        MONO_MT_BLOB_IDX,   /* "Signature" }, */
        MONO_MT_END,

#define GEN_CONSTRAINT_SCHEMA_OFFSET METHOD_SPEC_SCHEMA_OFFSET + 3
        MONO_MT_TABLE_IDX,  /* "GenericParam" }, */
        MONO_MT_TDOR_IDX,   /* "Constraint" }, */
        MONO_MT_END,

#define DOCUMENT_SCHEMA_OFFSET GEN_CONSTRAINT_SCHEMA_OFFSET + 3
        MONO_MT_BLOB_IDX,   /* Name */
        MONO_MT_GUID_IDX,   /* HashAlgorithm */
        MONO_MT_BLOB_IDX,   /* Hash */
        MONO_MT_GUID_IDX,   /* Language */
        MONO_MT_END,

#define METHODBODY_SCHEMA_OFFSET DOCUMENT_SCHEMA_OFFSET + 5
        MONO_MT_TABLE_IDX,   /* Document */
        MONO_MT_BLOB_IDX,   /* SequencePoints */
        MONO_MT_END,

#define LOCALSCOPE_SCHEMA_OFFSET METHODBODY_SCHEMA_OFFSET + 3
        MONO_MT_TABLE_IDX,   /* Method */
        MONO_MT_TABLE_IDX,   /* ImportScope */
        MONO_MT_TABLE_IDX,   /* VariableList */
        MONO_MT_TABLE_IDX,   /* ConstantList */
        MONO_MT_UINT32,      /* StartOffset */
        MONO_MT_UINT32,      /* Length */
        MONO_MT_END,

#define LOCALVARIABLE_SCHEMA_OFFSET LOCALSCOPE_SCHEMA_OFFSET + 7
        MONO_MT_UINT16,      /* Attributes */
        MONO_MT_UINT16,      /* Index */
        MONO_MT_STRING_IDX,  /* Name */
        MONO_MT_END,

#define LOCALCONSTANT_SCHEMA_OFFSET LOCALVARIABLE_SCHEMA_OFFSET + 4
        MONO_MT_STRING_IDX,  /* Name (String heap index) */
        MONO_MT_BLOB_IDX,    /* Signature (Blob heap index, LocalConstantSig blob) */
        MONO_MT_END,

#define IMPORTSCOPE_SCHEMA_OFFSET LOCALCONSTANT_SCHEMA_OFFSET + 3
        MONO_MT_TABLE_IDX, /* Parent (ImportScope row id or nil) */
        MONO_MT_BLOB_IDX,  /* Imports (Blob index, encoding: Imports blob) */
        MONO_MT_END,

#define ASYNCMETHOD_SCHEMA_OFFSET IMPORTSCOPE_SCHEMA_OFFSET + 3
        MONO_MT_TABLE_IDX, /* MoveNextMethod (MethodDef row id) */
        MONO_MT_TABLE_IDX, /* KickoffMethod (MethodDef row id) */
        MONO_MT_END,

#define CUSTOMDEBUGINFORMATION_SCHEMA_OFFSET ASYNCMETHOD_SCHEMA_OFFSET + 3
        MONO_MT_HASCUSTDEBUG_IDX, /* Parent (HasCustomDebugInformation coded index) */
        MONO_MT_GUID_IDX,  /* Kind (Guid heap index) */
        MONO_MT_BLOB_IDX,  /* Value (Blob heap index) */
        MONO_MT_END,

#define NULL_SCHEMA_OFFSET CUSTOMDEBUGINFORMATION_SCHEMA_OFFSET + 4
        MONO_MT_END
};

/* Must be the same order as MONO_TABLE_* */
const static unsigned char
table_description [] = {
        MODULE_SCHEMA_OFFSET,
        TYPEREF_SCHEMA_OFFSET,
        TYPEDEF_SCHEMA_OFFSET,
        FIELD_POINTER_SCHEMA_OFFSET,
        FIELD_SCHEMA_OFFSET,
        METHOD_POINTER_SCHEMA_OFFSET,
        METHOD_SCHEMA_OFFSET,
        PARAM_POINTER_SCHEMA_OFFSET,
        PARAM_SCHEMA_OFFSET,
        IFACEMAP_SCHEMA_OFFSET,
        MEMBERREF_SCHEMA_OFFSET, /* 0xa */
        CONSTANT_SCHEMA_OFFSET,
        CUSTOM_ATTR_SCHEMA_OFFSET,
        FIELD_MARSHAL_SCHEMA_OFFSET,
        DECL_SEC_SCHEMA_OFFSET,
        CLASS_LAYOUT_SCHEMA_OFFSET,
        FIELD_LAYOUT_SCHEMA_OFFSET, /* 0x10 */
        STDALON_SIG_SCHEMA_OFFSET,
        EVENTMAP_SCHEMA_OFFSET,
        EVENT_POINTER_SCHEMA_OFFSET,
        EVENT_SCHEMA_OFFSET,
        PROPERTY_MAP_SCHEMA_OFFSET,
        PROPERTY_POINTER_SCHEMA_OFFSET,
        PROPERTY_SCHEMA_OFFSET,
        METHOD_SEMA_SCHEMA_OFFSET,
        METHOD_IMPL_SCHEMA_OFFSET,
        MODULEREF_SCHEMA_OFFSET, /* 0x1a */
        TYPESPEC_SCHEMA_OFFSET,
        IMPLMAP_SCHEMA_OFFSET,
        FIELD_RVA_SCHEMA_OFFSET,
        NULL_SCHEMA_OFFSET,
        NULL_SCHEMA_OFFSET,
        ASSEMBLY_SCHEMA_OFFSET, /* 0x20 */
        ASSEMBLYPROC_SCHEMA_OFFSET,
        ASSEMBLYOS_SCHEMA_OFFSET,
        ASSEMBLYREF_SCHEMA_OFFSET,
        ASSEMBLYREFPROC_SCHEMA_OFFSET,
        ASSEMBLYREFOS_SCHEMA_OFFSET,
        FILE_SCHEMA_OFFSET,
        EXPORTED_TYPE_SCHEMA_OFFSET,
        MANIFEST_SCHEMA_OFFSET,
        NESTED_CLASS_SCHEMA_OFFSET,
        GENPARAM_SCHEMA_OFFSET, /* 0x2a */
        METHOD_SPEC_SCHEMA_OFFSET,
        GEN_CONSTRAINT_SCHEMA_OFFSET,
        NULL_SCHEMA_OFFSET,
        NULL_SCHEMA_OFFSET,
        NULL_SCHEMA_OFFSET,
        DOCUMENT_SCHEMA_OFFSET, /* 0x30 */
        METHODBODY_SCHEMA_OFFSET,
        LOCALSCOPE_SCHEMA_OFFSET,
        LOCALVARIABLE_SCHEMA_OFFSET,
        LOCALCONSTANT_SCHEMA_OFFSET,
        IMPORTSCOPE_SCHEMA_OFFSET,
        ASYNCMETHOD_SCHEMA_OFFSET,
        CUSTOMDEBUGINFORMATION_SCHEMA_OFFSET
};

// This, instead of an array of pointers, to optimize away a pointer and a relocation per string.
#define MSGSTRFIELD(line) MSGSTRFIELD1(line)
#define MSGSTRFIELD1(line) str##line
static const struct msgstr_t {
#define TABLEDEF(a,b) char MSGSTRFIELD(__LINE__) [sizeof (b)];
#include "mono/cil/tables.def"
#undef TABLEDEF
} tablestr = {
#define TABLEDEF(a,b) b,
#include "mono/cil/tables.def"
#undef TABLEDEF
};
static const gint16 tableidx [] = {
#define TABLEDEF(a,b) offsetof (struct msgstr_t, MSGSTRFIELD(__LINE__)),
#include "mono/cil/tables.def"
#undef TABLEDEF
};

/* On legacy, if TRUE (but also see DISABLE_DESKTOP_LOADER #define), Mono will check
 * that the public key token, culture and version of a candidate assembly matches
 * the requested strong name. On netcore, it will check the culture and version.
 * If FALSE, as long as the name matches, the candidate will be allowed.
 */
static gboolean check_assembly_names_strictly = FALSE;

// Amount initially reserved in each imageset's mempool.
// FIXME: This number is arbitrary, a more practical number should be found
#define INITIAL_IMAGE_SET_SIZE    1024

/**
 * mono_meta_table_name:
 * \param table table index
 *
 * Returns the name of the given ECMA metadata logical format table
 * as described in ECMA 335, Partition II, Section 22.
 * 
 * \returns the name for the \p table index
 */
const char *
mono_meta_table_name (int table)
{
        if ((table < 0) || (table > MONO_TABLE_LAST))
                return "";

        return (const char*)&tablestr + tableidx [table];
}

/* The guy who wrote the spec for this should not be allowed near a
 * computer again.
 
If  e is a coded token(see clause 23.1.7) that points into table ti out of n possible tables t0, .. tn-1, 
then it is stored as e << (log n) & tag{ t0, .. tn-1}[ ti] using 2 bytes if the maximum number of 
rows of tables t0, ..tn-1, is less than 2^16 - (log n), and using 4 bytes otherwise. The family of 
finite maps tag{ t0, ..tn-1} is defined below. Note that to decode a physical row, you need the 
inverse of this mapping.

 */
#define rtsize(meta,s,b) (((s) < (1 << (b)) ? 2 : 4))

static int
idx_size (MonoImage *meta, int idx)
{
        if (meta->referenced_tables && (meta->referenced_tables & ((guint64)1 << idx)))
                return meta->referenced_table_rows [idx] < 65536 ? 2 : 4;
        else
                return meta->tables [idx].rows < 65536 ? 2 : 4;
}

static int
get_nrows (MonoImage *meta, int idx)
{
        if (meta->referenced_tables && (meta->referenced_tables & ((guint64)1 << idx)))
                return meta->referenced_table_rows [idx];
        else
                return meta->tables [idx].rows;
}

/* Reference: Partition II - 23.2.6 */
/**
 * mono_metadata_compute_size:
 * \param meta metadata context
 * \param tableindex metadata table number
 * \param result_bitfield pointer to \c guint32 where to store additional info
 * 
 * \c mono_metadata_compute_size computes the length in bytes of a single
 * row in a metadata table. The size of each column is encoded in the
 * \p result_bitfield return value along with the number of columns in the table.
 * the resulting bitfield should be handed to the \c mono_metadata_table_size
 * and \c mono_metadata_table_count macros.
 * This is a Mono runtime internal only function.
 */
int
mono_metadata_compute_size (MonoImage *meta, int tableindex, guint32 *result_bitfield)
{
        guint32 bitfield = 0;
        int size = 0, field_size = 0;
        int i, n, code;
        int shift = 0;
        const unsigned char *description = TableSchemas + table_description [tableindex];

        for (i = 0; (code = description [i]) != MONO_MT_END; i++){
                switch (code){
                case MONO_MT_UINT32:
                        field_size = 4; break;
                        
                case MONO_MT_UINT16:
                        field_size = 2; break;
                        
                case MONO_MT_UINT8:
                        field_size = 1; break;
                        
                case MONO_MT_BLOB_IDX:
                        field_size = meta->idx_blob_wide ? 4 : 2; break;
                        
                case MONO_MT_STRING_IDX:
                        field_size = meta->idx_string_wide ? 4 : 2; break;
                        
                case MONO_MT_GUID_IDX:
                        field_size = meta->idx_guid_wide ? 4 : 2; break;

                case MONO_MT_TABLE_IDX:
                        /* Uhm, a table index can point to other tables besides the current one
                         * so, it's not correct to use the rowcount of the current table to
                         * get the size for this column - lupus 
                         */
                        switch (tableindex) {
                        case MONO_TABLE_ASSEMBLYREFOS:
                                g_assert (i == 3);
                                field_size = idx_size (meta, MONO_TABLE_ASSEMBLYREF); break;
                        case MONO_TABLE_ASSEMBLYREFPROCESSOR:
                                g_assert (i == 1);
                                field_size = idx_size (meta, MONO_TABLE_ASSEMBLYREF); break;
                        case MONO_TABLE_CLASSLAYOUT:
                                g_assert (i == 2);
                                field_size = idx_size (meta, MONO_TABLE_TYPEDEF); break;
                        case MONO_TABLE_EVENTMAP:
                                g_assert (i == 0 || i == 1);
                                field_size = i ? idx_size (meta, MONO_TABLE_EVENT):
                                        idx_size (meta, MONO_TABLE_TYPEDEF);
                                break;
                        case MONO_TABLE_EVENT_POINTER:
                                g_assert (i == 0);
                                field_size = idx_size (meta, MONO_TABLE_EVENT); break;
                        case MONO_TABLE_EXPORTEDTYPE:
                                g_assert (i == 1);
                                /* the index is in another metadata file, so it must be 4 */
                                field_size = 4; break;
                        case MONO_TABLE_FIELDLAYOUT:
                                g_assert (i == 1);
                                field_size = idx_size (meta, MONO_TABLE_FIELD); break;
                        case MONO_TABLE_FIELDRVA:
                                g_assert (i == 1);
                                field_size = idx_size (meta, MONO_TABLE_FIELD); break;
                        case MONO_TABLE_FIELD_POINTER:
                                g_assert (i == 0);
                                field_size = idx_size (meta, MONO_TABLE_FIELD); break;
                        case MONO_TABLE_IMPLMAP:
                                g_assert (i == 3);
                                field_size = idx_size (meta, MONO_TABLE_MODULEREF); break;
                        case MONO_TABLE_INTERFACEIMPL:
                                g_assert (i == 0);
                                field_size = idx_size (meta, MONO_TABLE_TYPEDEF); break;
                        case MONO_TABLE_METHOD:
                                g_assert (i == 5);
                                field_size = idx_size (meta, MONO_TABLE_PARAM); break;
                        case MONO_TABLE_METHODIMPL:
                                g_assert (i == 0);
                                field_size = idx_size (meta, MONO_TABLE_TYPEDEF); break;
                        case MONO_TABLE_METHODSEMANTICS:
                                g_assert (i == 1);
                                field_size = idx_size (meta, MONO_TABLE_METHOD); break;
                        case MONO_TABLE_METHOD_POINTER:
                                g_assert (i == 0);
                                field_size = idx_size (meta, MONO_TABLE_METHOD); break;
                        case MONO_TABLE_NESTEDCLASS:
                                g_assert (i == 0 || i == 1);
                                field_size = idx_size (meta, MONO_TABLE_TYPEDEF); break;
                        case MONO_TABLE_PARAM_POINTER:
                                g_assert (i == 0);
                                field_size = idx_size (meta, MONO_TABLE_PARAM); break;
                        case MONO_TABLE_PROPERTYMAP:
                                g_assert (i == 0 || i == 1);
                                field_size = i ? idx_size (meta, MONO_TABLE_PROPERTY):
                                        idx_size (meta, MONO_TABLE_TYPEDEF);
                                break;
                        case MONO_TABLE_PROPERTY_POINTER:
                                g_assert (i == 0);
                                field_size = idx_size (meta, MONO_TABLE_PROPERTY); break;
                        case MONO_TABLE_TYPEDEF:
                                g_assert (i == 4 || i == 5);
                                field_size = i == 4 ? idx_size (meta, MONO_TABLE_FIELD):
                                        idx_size (meta, MONO_TABLE_METHOD);
                                break;
                        case MONO_TABLE_GENERICPARAM:
                                g_assert (i == 2);
                                n = MAX (get_nrows (meta, MONO_TABLE_METHOD), get_nrows (meta, MONO_TABLE_TYPEDEF));
                                /*This is a coded token for 2 tables, so takes 1 bit */
                                field_size = rtsize (meta, n, 16 - MONO_TYPEORMETHOD_BITS);
                                break;
                        case MONO_TABLE_GENERICPARAMCONSTRAINT:
                                g_assert (i == 0);
                                field_size = idx_size (meta, MONO_TABLE_GENERICPARAM);
                                break;
                        case MONO_TABLE_LOCALSCOPE:
                                switch (i) {
                                case 0:
                                        // FIXME: This table is in another file
                                        field_size = idx_size (meta, MONO_TABLE_METHOD);
                                        break;
                                case 1:
                                        field_size = idx_size (meta, MONO_TABLE_IMPORTSCOPE);
                                        break;
                                case 2:
                                        field_size = idx_size (meta, MONO_TABLE_LOCALVARIABLE);
                                        break;
                                case 3:
                                        field_size = idx_size (meta, MONO_TABLE_LOCALCONSTANT);
                                        break;
                                default:
                                        g_assert_not_reached ();
                                        break;
                                }
                                break;
                        case MONO_TABLE_METHODBODY:
                                g_assert (i == 0);
                                field_size = idx_size (meta, MONO_TABLE_DOCUMENT); break;
                        case MONO_TABLE_IMPORTSCOPE:
                                g_assert(i == 0);
                                field_size = idx_size (meta, MONO_TABLE_IMPORTSCOPE); break;
                        case MONO_TABLE_STATEMACHINEMETHOD:
                                g_assert(i == 0 || i == 1);
                                field_size = idx_size(meta, MONO_TABLE_METHOD); break;
                        default:
                                g_error ("Can't handle MONO_MT_TABLE_IDX for table %d element %d", tableindex, i);
                        }
                        break;

                        /*
                         * HasConstant: ParamDef, FieldDef, Property
                         */
                case MONO_MT_CONST_IDX:
                        n = MAX (get_nrows (meta, MONO_TABLE_PARAM),
                                 get_nrows (meta, MONO_TABLE_FIELD));
                        n = MAX (n, get_nrows (meta, MONO_TABLE_PROPERTY));

                        /* 2 bits to encode tag */
                        field_size = rtsize (meta, n, 16-2);
                        break;

                        /*
                         * HasCustomAttribute: points to any table but
                         * itself.
                         */
                case MONO_MT_HASCAT_IDX:
                        /*
                         * We believe that since the signature and
                         * permission are indexing the Blob heap,
                         * we should consider the blob size first
                         */
                        /* I'm not a believer - lupus
                        if (meta->idx_blob_wide){
                                field_size = 4;
                                break;
                        }*/
                        
                        n = MAX (get_nrows (meta, MONO_TABLE_METHOD),
                                 get_nrows (meta, MONO_TABLE_FIELD));
                        n = MAX (n, get_nrows (meta, MONO_TABLE_TYPEREF));
                        n = MAX (n, get_nrows (meta, MONO_TABLE_TYPEDEF));
                        n = MAX (n, get_nrows (meta, MONO_TABLE_PARAM));
                        n = MAX (n, get_nrows (meta, MONO_TABLE_INTERFACEIMPL));
                        n = MAX (n, get_nrows (meta, MONO_TABLE_MEMBERREF));
                        n = MAX (n, get_nrows (meta, MONO_TABLE_MODULE));
                        n = MAX (n, get_nrows (meta, MONO_TABLE_DECLSECURITY));
                        n = MAX (n, get_nrows (meta, MONO_TABLE_PROPERTY));
                        n = MAX (n, get_nrows (meta, MONO_TABLE_EVENT));
                        n = MAX (n, get_nrows (meta, MONO_TABLE_STANDALONESIG));
                        n = MAX (n, get_nrows (meta, MONO_TABLE_MODULEREF));
                        n = MAX (n, get_nrows (meta, MONO_TABLE_TYPESPEC));
                        n = MAX (n, get_nrows (meta, MONO_TABLE_ASSEMBLY));
                        n = MAX (n, get_nrows (meta, MONO_TABLE_ASSEMBLYREF));
                        n = MAX (n, get_nrows (meta, MONO_TABLE_FILE));
                        n = MAX (n, get_nrows (meta, MONO_TABLE_EXPORTEDTYPE));
                        n = MAX (n, get_nrows (meta, MONO_TABLE_MANIFESTRESOURCE));
                        n = MAX (n, get_nrows (meta, MONO_TABLE_GENERICPARAM));
                        n = MAX (n, get_nrows (meta, MONO_TABLE_GENERICPARAMCONSTRAINT));
                        n = MAX (n, get_nrows (meta, MONO_TABLE_METHODSPEC));

                        /* 5 bits to encode */
                        field_size = rtsize (meta, n, 16-5);
                        break;

                        /*
                        * HasCustomAttribute: points to any table but
                        * itself.
                        */

                case MONO_MT_HASCUSTDEBUG_IDX:
                        n = MAX(get_nrows (meta, MONO_TABLE_METHOD),
                                        get_nrows (meta, MONO_TABLE_FIELD));
                        n = MAX(n, get_nrows (meta, MONO_TABLE_TYPEREF));
                        n = MAX(n, get_nrows (meta, MONO_TABLE_TYPEDEF));
                        n = MAX(n, get_nrows (meta, MONO_TABLE_PARAM));
                        n = MAX(n, get_nrows (meta, MONO_TABLE_INTERFACEIMPL));
                        n = MAX(n, get_nrows (meta, MONO_TABLE_MEMBERREF));
                        n = MAX(n, get_nrows (meta, MONO_TABLE_MODULE));
                        n = MAX(n, get_nrows (meta, MONO_TABLE_DECLSECURITY));
                        n = MAX(n, get_nrows (meta, MONO_TABLE_PROPERTY));
                        n = MAX(n, get_nrows (meta, MONO_TABLE_EVENT));
                        n = MAX(n, get_nrows (meta, MONO_TABLE_STANDALONESIG));
                        n = MAX(n, get_nrows (meta, MONO_TABLE_MODULEREF));
                        n = MAX(n, get_nrows (meta, MONO_TABLE_TYPESPEC));
                        n = MAX(n, get_nrows (meta, MONO_TABLE_ASSEMBLY));
                        n = MAX(n, get_nrows (meta, MONO_TABLE_ASSEMBLYREF));
                        n = MAX(n, get_nrows (meta, MONO_TABLE_FILE));
                        n = MAX(n, get_nrows (meta, MONO_TABLE_EXPORTEDTYPE));
                        n = MAX(n, get_nrows (meta, MONO_TABLE_MANIFESTRESOURCE));
                        n = MAX(n, get_nrows (meta, MONO_TABLE_GENERICPARAM));
                        n = MAX(n, get_nrows (meta, MONO_TABLE_GENERICPARAMCONSTRAINT));
                        n = MAX(n, get_nrows (meta, MONO_TABLE_METHODSPEC));
                        n = MAX(n, get_nrows (meta, MONO_TABLE_DOCUMENT));
                        n = MAX(n, get_nrows (meta, MONO_TABLE_LOCALSCOPE));
                        n = MAX(n, get_nrows (meta, MONO_TABLE_LOCALVARIABLE));
                        n = MAX(n, get_nrows (meta, MONO_TABLE_LOCALCONSTANT));
                        n = MAX(n, get_nrows (meta, MONO_TABLE_IMPORTSCOPE));

                        /* 5 bits to encode */
                        field_size = rtsize(meta, n, 16 - 5);
                        break;

                        /*
                         * CustomAttributeType: MethodDef, MemberRef.
                         */
                case MONO_MT_CAT_IDX:
                        n = MAX (get_nrows (meta, MONO_TABLE_METHOD),
                                         get_nrows (meta, MONO_TABLE_MEMBERREF));

                        /* 3 bits to encode */
                        field_size = rtsize (meta, n, 16-3);
                        break;

                        /*
                         * HasDeclSecurity: Typedef, MethodDef, Assembly
                         */
                case MONO_MT_HASDEC_IDX:
                        n = MAX (get_nrows (meta, MONO_TABLE_TYPEDEF),
                                 get_nrows (meta, MONO_TABLE_METHOD));
                        n = MAX (n, get_nrows (meta, MONO_TABLE_ASSEMBLY));

                        /* 2 bits to encode */
                        field_size = rtsize (meta, n, 16-2);
                        break;

                        /*
                         * Implementation: File, AssemblyRef, ExportedType
                         */
                case MONO_MT_IMPL_IDX:
                        n = MAX (get_nrows (meta, MONO_TABLE_FILE),
                                 get_nrows (meta, MONO_TABLE_ASSEMBLYREF));
                        n = MAX (n, get_nrows (meta, MONO_TABLE_EXPORTEDTYPE));

                        /* 2 bits to encode tag */
                        field_size = rtsize (meta, n, 16-2);
                        break;

                        /*
                         * HasFieldMarshall: FieldDef, ParamDef
                         */
                case MONO_MT_HFM_IDX:
                        n = MAX (get_nrows (meta, MONO_TABLE_FIELD),
                                 get_nrows (meta, MONO_TABLE_PARAM));

                        /* 1 bit used to encode tag */
                        field_size = rtsize (meta, n, 16-1);
                        break;

                        /*
                         * MemberForwarded: FieldDef, MethodDef
                         */
                case MONO_MT_MF_IDX:
                        n = MAX (get_nrows (meta, MONO_TABLE_FIELD),
                                 get_nrows (meta, MONO_TABLE_METHOD));

                        /* 1 bit used to encode tag */
                        field_size = rtsize (meta, n, 16-1);
                        break;

                        /*
                         * TypeDefOrRef: TypeDef, ParamDef, TypeSpec
                         * LAMESPEC
                         * It is TypeDef, _TypeRef_, TypeSpec, instead.
                         */
                case MONO_MT_TDOR_IDX:
                        n = MAX (get_nrows (meta, MONO_TABLE_TYPEDEF),
                                 get_nrows (meta, MONO_TABLE_TYPEREF));
                        n = MAX (n, get_nrows (meta, MONO_TABLE_TYPESPEC));

                        /* 2 bits to encode */
                        field_size = rtsize (meta, n, 16-2);
                        break;

                        /*
                         * MemberRefParent: TypeDef, TypeRef, MethodDef, ModuleRef, TypeSpec, MemberRef
                         */
                case MONO_MT_MRP_IDX:
                        n = MAX (get_nrows (meta, MONO_TABLE_TYPEDEF),
                                 get_nrows (meta, MONO_TABLE_TYPEREF));
                        n = MAX (n, get_nrows (meta, MONO_TABLE_METHOD));
                        n = MAX (n, get_nrows (meta, MONO_TABLE_MODULEREF));
                        n = MAX (n, get_nrows (meta, MONO_TABLE_TYPESPEC));

                        /* 3 bits to encode */
                        field_size = rtsize (meta, n, 16 - 3);
                        break;
                        
                        /*
                         * MethodDefOrRef: MethodDef, MemberRef
                         */
                case MONO_MT_MDOR_IDX:
                        n = MAX (get_nrows (meta, MONO_TABLE_METHOD),
                                 get_nrows (meta, MONO_TABLE_MEMBERREF));

                        /* 1 bit used to encode tag */
                        field_size = rtsize (meta, n, 16-1);
                        break;
                        
                        /*
                         * HasSemantics: Property, Event
                         */
                case MONO_MT_HS_IDX:
                        n = MAX (get_nrows (meta, MONO_TABLE_PROPERTY),
                                 get_nrows (meta, MONO_TABLE_EVENT));

                        /* 1 bit used to encode tag */
                        field_size = rtsize (meta, n, 16-1);
                        break;

                        /*
                         * ResolutionScope: Module, ModuleRef, AssemblyRef, TypeRef
                         */
                case MONO_MT_RS_IDX:
                        n = MAX (get_nrows (meta, MONO_TABLE_MODULE),
                                 get_nrows (meta, MONO_TABLE_MODULEREF));
                        n = MAX (n, get_nrows (meta, MONO_TABLE_ASSEMBLYREF));
                        n = MAX (n, get_nrows (meta, MONO_TABLE_TYPEREF));

                        /* 2 bits used to encode tag (ECMA spec claims 3) */
                        field_size = rtsize (meta, n, 16 - 2);
                        break;
                }

                /*
                 * encode field size as follows (we just need to
                 * distinguish them).
                 *
                 * 4 -> 3
                 * 2 -> 1
                 * 1 -> 0
                 */
                bitfield |= (field_size-1) << shift;
                shift += 2;
                size += field_size;
                /*g_print ("table %02x field %d size %d\n", tableindex, i, field_size);*/
        }

        *result_bitfield = (i << 24) | bitfield;
        return size;
}

/**
 * mono_metadata_compute_table_bases:
 * \param meta metadata context to compute table values
 *
 * Computes the table bases for the metadata structure.
 * This is an internal function used by the image loader code.
 */
void
mono_metadata_compute_table_bases (MonoImage *meta)
{
        int i;
        const char *base = meta->tables_base;
        
        for (i = 0; i < MONO_TABLE_NUM; i++) {
                MonoTableInfo *table = &meta->tables [i];
                if (table->rows == 0)
                        continue;

                table->row_size = mono_metadata_compute_size (meta, i, &table->size_bitfield);
                table->base = base;
                base += table->rows * table->row_size;
        }
}

/**
 * mono_metadata_locate:
 * \param meta metadata context
 * \param table table code.
 * \param idx index of element to retrieve from \p table.
 *
 * \returns a pointer to the \p idx element in the metadata table
 * whose code is \p table.
 */
const char *
mono_metadata_locate (MonoImage *meta, int table, int idx)
{
        /* idx == 0 refers always to NULL */
        g_return_val_if_fail (idx > 0 && idx <= meta->tables [table].rows, ""); /*FIXME shouldn't we return NULL here?*/
           
        return meta->tables [table].base + (meta->tables [table].row_size * (idx - 1));
}

/**
 * mono_metadata_locate_token:
 * \param meta metadata context
 * \param token metadata token
 *
 * \returns a pointer to the data in the metadata represented by the
 * token \p token .
 */
const char *
mono_metadata_locate_token (MonoImage *meta, guint32 token)
{
        return mono_metadata_locate (meta, token >> 24, token & 0xffffff);
}

/**
 * mono_metadata_string_heap:
 * \param meta metadata context
 * \param index index into the string heap.
 * \returns an in-memory pointer to the \p index in the string heap.
 */
const char *
mono_metadata_string_heap (MonoImage *meta, guint32 index)
{
        g_assert (index < meta->heap_strings.size);
        g_return_val_if_fail (index < meta->heap_strings.size, "");
        return meta->heap_strings.data + index;
}

/**
 * mono_metadata_string_heap_checked:
 * \param meta metadata context
 * \param index index into the string heap.
 * \param error set on error
 * \returns an in-memory pointer to the \p index in the string heap.
 * On failure returns NULL and sets \p error.
 */
const char *
mono_metadata_string_heap_checked (MonoImage *meta, guint32 index, MonoError *error)
{
        if (G_UNLIKELY (!(index < meta->heap_strings.size))) {
                mono_error_set_bad_image_by_name (error, meta->name ? meta->name : "unknown image", "string heap index %ud out bounds %u", index, meta->heap_strings.size);
                return NULL;
        }
        return meta->heap_strings.data + index;
}

/**
 * mono_metadata_user_string:
 * \param meta metadata context
 * \param index index into the user string heap.
 * \returns an in-memory pointer to the \p index in the user string heap (<code>#US</code>).
 */
const char *
mono_metadata_user_string (MonoImage *meta, guint32 index)
{
        g_assert (index < meta->heap_us.size);
        g_return_val_if_fail (index < meta->heap_us.size, "");
        return meta->heap_us.data + index;
}

/**
 * mono_metadata_blob_heap:
 * \param meta metadata context
 * \param index index into the blob.
 * \returns an in-memory pointer to the \p index in the Blob heap.
 */
const char *
mono_metadata_blob_heap (MonoImage *meta, guint32 index)
{
        /* Some tools can produce assemblies with a size 0 Blob stream. If a
         * blob value is optional, if the index == 0 and heap_blob.size == 0
         * assertion is hit, consider updating caller to use
         * mono_metadata_blob_heap_null_ok and handling a null return value. */
        g_assert (!(index == 0 && meta->heap_blob.size == 0));
        g_assert (index < meta->heap_blob.size);
        return meta->heap_blob.data + index;
}

/**
 * mono_metadata_blob_heap_null_ok:
 * \param meta metadata context
 * \param index index into the blob.
 * \return an in-memory pointer to the \p index in the Blob heap.
 * If the Blob heap is empty or missing and index is 0 returns NULL, instead of asserting.
 */
const char *
mono_metadata_blob_heap_null_ok (MonoImage *meta, guint32 index)
{
        if (G_UNLIKELY (index == 0 && meta->heap_blob.size == 0))
                return NULL;
        else
                return mono_metadata_blob_heap (meta, index);
}

/**
 * mono_metadata_blob_heap_checked:
 * \param meta metadata context
 * \param index index into the blob.
 * \param error set on error
 * \returns an in-memory pointer to the \p index in the Blob heap.  On failure sets \p error and returns NULL;
 * If the Blob heap is empty or missing and \p index is 0 returns NULL, without setting error.
 *
 */
const char *
mono_metadata_blob_heap_checked (MonoImage *meta, guint32 index, MonoError *error)
{
        if (G_UNLIKELY (index == 0 && meta->heap_blob.size == 0))
                return NULL;
        if (G_UNLIKELY (!(index < meta->heap_blob.size))) {
                mono_error_set_bad_image_by_name (error, meta->name ? meta->name : "unknown image", "blob heap index %u out of bounds %u", index, meta->heap_blob.size);
                return NULL;
        }
        return meta->heap_blob.data + index;
}

/**
 * mono_metadata_guid_heap:
 * \param meta metadata context
 * \param index index into the guid heap.
 * \returns an in-memory pointer to the \p index in the guid heap.
 */
const char *
mono_metadata_guid_heap (MonoImage *meta, guint32 index)
{
        --index;
        index *= 16; /* adjust for guid size and 1-based index */
        g_return_val_if_fail (index < meta->heap_guid.size, "");
        return meta->heap_guid.data + index;
}

static const unsigned char *
dword_align (const unsigned char *ptr)
{
        return (const unsigned char *) (((gsize) (ptr + 3)) & ~3);
}

/**
 * mono_metadata_decode_row:
 * \param t table to extract information from.
 * \param idx index in table.
 * \param res array of \p res_size cols to store the results in
 *
 * This decompresses the metadata element \p idx in table \p t
 * into the \c guint32 \p res array that has \p res_size elements
 */
void
mono_metadata_decode_row (const MonoTableInfo *t, int idx, guint32 *res, int res_size)
{
        guint32 bitfield = t->size_bitfield;
        int i, count = mono_metadata_table_count (bitfield);
        const char *data;

        g_assert (idx < t->rows);
        g_assert (idx >= 0);
        data = t->base + idx * t->row_size;
        
        g_assert (res_size == count);

        for (i = 0; i < count; i++) {
                int n = mono_metadata_table_size (bitfield, i);

                switch (n){
                case 1:
                        res [i] = *data; break;
                case 2:
                        res [i] = read16 (data); break;
                case 4:
                        res [i] = read32 (data); break;
                default:
                        g_assert_not_reached ();
                }
                data += n;
        }
}

/**
 * mono_metadata_decode_row_checked:
 * \param image the \c MonoImage the table belongs to
 * \param t table to extract information from.
 * \param idx index in the table.
 * \param res array of \p res_size cols to store the results in
 * \param error set on bounds error
 *
 *
 * This decompresses the metadata element \p idx in the table \p t
 * into the \c guint32 \p res array that has \p res_size elements.
 *
 * \returns TRUE if the read succeeded. Otherwise sets \p error and returns FALSE.
 */
gboolean
mono_metadata_decode_row_checked (const MonoImage *image, const MonoTableInfo *t, int idx, guint32 *res, int res_size, MonoError *error)
{
        guint32 bitfield = t->size_bitfield;
        int i, count = mono_metadata_table_count (bitfield);

        const char *image_name = image && image->name ? image->name : "unknown image";

        if (G_UNLIKELY (! (idx < t->rows && idx >= 0))) {
                mono_error_set_bad_image_by_name (error, image_name, "row index %d out of bounds: %d rows", idx, t->rows);
                return FALSE;
        }
        const char *data = t->base + idx * t->row_size;

        if (G_UNLIKELY (res_size != count)) {
                mono_error_set_bad_image_by_name (error, image_name, "res_size %d != count %d", res_size, count);
                return FALSE;
        }

        for (i = 0; i < count; i++) {
                int n = mono_metadata_table_size (bitfield, i);

                switch (n) {
                case 1:
                        res [i] = *data; break;
                case 2:
                        res [i] = read16 (data); break;
                case 4:
                        res [i] = read32 (data); break;
                default:
                        mono_error_set_bad_image_by_name (error, image_name, "unexpected table [%d] size %d", i, n);
                        return FALSE;
                }
                data += n;
        }

        return TRUE;
}

/**
 * mono_metadata_decode_row_col:
 * \param t table to extract information from.
 * \param idx index for row in table.
 * \param col column in the row.
 *
 * This function returns the value of column \p col from the \p idx
 * row in the table \p t .
 */
guint32
mono_metadata_decode_row_col (const MonoTableInfo *t, int idx, guint col)
{
        guint32 bitfield = t->size_bitfield;
        int i;
        const char *data;
        int n;
        
        g_assert (idx < t->rows);
        g_assert (col < mono_metadata_table_count (bitfield));
        data = t->base + idx * t->row_size;

        n = mono_metadata_table_size (bitfield, 0);
        for (i = 0; i < col; ++i) {
                data += n;
                n = mono_metadata_table_size (bitfield, i + 1);
        }
        switch (n) {
        case 1:
                return *data;
        case 2:
                return read16 (data);
        case 4:
                return read32 (data);
        default:
                g_assert_not_reached ();
        }
        return 0;
}

/**
 * mono_metadata_decode_blob_size:
 * \param ptr pointer to a blob object
 * \param rptr the new position of the pointer
 *
 * This decodes a compressed size as described by 24.2.4 (#US and #Blob a blob or user string object)
 *
 * \returns the size of the blob object
 */
guint32
mono_metadata_decode_blob_size (const char *xptr, const char **rptr)
{
        const unsigned char *ptr = (const unsigned char *)xptr;
        guint32 size;
        
        if ((*ptr & 0x80) == 0){
                size = ptr [0] & 0x7f;
                ptr++;
        } else if ((*ptr & 0x40) == 0){
                size = ((ptr [0] & 0x3f) << 8) + ptr [1];
                ptr += 2;
        } else {
                size = ((ptr [0] & 0x1f) << 24) +
                        (ptr [1] << 16) +
                        (ptr [2] << 8) +
                        ptr [3];
                ptr += 4;
        }
        if (rptr)
                *rptr = (char*)ptr;
        return size;
}

/**
 * mono_metadata_decode_value:
 * \param ptr pointer to decode from
 * \param rptr the new position of the pointer
 *
 * This routine decompresses 32-bit values as specified in the "Blob and
 * Signature" section (23.2)
 *
 * \returns the decoded value
 */
guint32
mono_metadata_decode_value (const char *_ptr, const char **rptr)
{
        const unsigned char *ptr = (const unsigned char *) _ptr;
        unsigned char b = *ptr;
        guint32 len;
        
        if ((b & 0x80) == 0){
                len = b;
                ++ptr;
        } else if ((b & 0x40) == 0){
                len = ((b & 0x3f) << 8 | ptr [1]);
                ptr += 2;
        } else {
                len = ((b & 0x1f) << 24) |
                        (ptr [1] << 16) |
                        (ptr [2] << 8) |
                        ptr [3];
                ptr += 4;
        }
        if (rptr)
                *rptr = (char*)ptr;
        
        return len;
}

/**
 * mono_metadata_decode_signed_value:
 * \param ptr pointer to decode from
 * \param rptr the new position of the pointer
 *
 * This routine decompresses 32-bit signed values
 * (not specified in the spec)
 *
 * \returns the decoded value
 */
gint32
mono_metadata_decode_signed_value (const char *ptr, const char **rptr)
{
        guint32 uval = mono_metadata_decode_value (ptr, rptr);
        gint32 ival = uval >> 1;
        if (!(uval & 1))
                return ival;
        /* ival is a truncated 2's complement negative number.  */
        if (ival < 0x40)
                /* 6 bits = 7 bits for compressed representation (top bit is '0') - 1 sign bit */
                return ival - 0x40;
        if (ival < 0x2000)
                /* 13 bits = 14 bits for compressed representation (top bits are '10') - 1 sign bit */
                return ival - 0x2000;
        if (ival < 0x10000000)
                /* 28 bits = 29 bits for compressed representation (top bits are '110') - 1 sign bit */
                return ival - 0x10000000;
        g_assert (ival < 0x20000000);
        g_warning ("compressed signed value appears to use 29 bits for compressed representation: %x (raw: %8x)", ival, uval);
        return ival - 0x20000000;
}

/**
 * mono_metadata_translate_token_index:
 * Translates the given 1-based index into the \c Method, \c Field, \c Event, or \c Param tables
 * using the \c *Ptr tables in uncompressed metadata, if they are available.
 *
 * FIXME: The caller is not forced to call this function, which is error-prone, since 
 * forgetting to call it would only show up as a bug on uncompressed metadata.
 */
guint32
mono_metadata_translate_token_index (MonoImage *image, int table, guint32 idx)
{
        if (!image->uncompressed_metadata)
                return idx;

        switch (table) {
        case MONO_TABLE_METHOD:
                if (image->tables [MONO_TABLE_METHOD_POINTER].rows)
                        return mono_metadata_decode_row_col (&image->tables [MONO_TABLE_METHOD_POINTER], idx - 1, MONO_METHOD_POINTER_METHOD);
                else
                        return idx;
        case MONO_TABLE_FIELD:
                if (image->tables [MONO_TABLE_FIELD_POINTER].rows)
                        return mono_metadata_decode_row_col (&image->tables [MONO_TABLE_FIELD_POINTER], idx - 1, MONO_FIELD_POINTER_FIELD);
                else
                        return idx;
        case MONO_TABLE_EVENT:
                if (image->tables [MONO_TABLE_EVENT_POINTER].rows)
                        return mono_metadata_decode_row_col (&image->tables [MONO_TABLE_EVENT_POINTER], idx - 1, MONO_EVENT_POINTER_EVENT);
                else
                        return idx;
        case MONO_TABLE_PROPERTY:
                if (image->tables [MONO_TABLE_PROPERTY_POINTER].rows)
                        return mono_metadata_decode_row_col (&image->tables [MONO_TABLE_PROPERTY_POINTER], idx - 1, MONO_PROPERTY_POINTER_PROPERTY);
                else
                        return idx;
        case MONO_TABLE_PARAM:
                if (image->tables [MONO_TABLE_PARAM_POINTER].rows)
                        return mono_metadata_decode_row_col (&image->tables [MONO_TABLE_PARAM_POINTER], idx - 1, MONO_PARAM_POINTER_PARAM);
                else
                        return idx;
        default:
                return idx;
        }
}

/**
 * mono_metadata_decode_table_row:
 *
 * Same as \c mono_metadata_decode_row, but takes an \p image + \p table ID pair, and takes
 * uncompressed metadata into account, so it should be used to access the
 * \c Method, \c Field, \c Param and \c Event tables when the access is made from metadata, i.e.
 * \p idx is retrieved from a metadata table, like \c MONO_TYPEDEF_FIELD_LIST.
 */
void
mono_metadata_decode_table_row (MonoImage *image, int table, int idx, guint32 *res, int res_size)
{
        if (image->uncompressed_metadata)
                idx = mono_metadata_translate_token_index (image, table, idx + 1) - 1;

        mono_metadata_decode_row (&image->tables [table], idx, res, res_size);
}

/**
 * mono_metadata_decode_table_row_col:
 *
 * Same as \c mono_metadata_decode_row_col, but takes an \p image + \p table ID pair, and takes
 * uncompressed metadata into account, so it should be used to access the
 * \c Method, \c Field, \c Param and \c Event tables.
 */
guint32 mono_metadata_decode_table_row_col (MonoImage *image, int table, int idx, guint col)
{
        if (image->uncompressed_metadata)
                idx = mono_metadata_translate_token_index (image, table, idx + 1) - 1;

        return mono_metadata_decode_row_col (&image->tables [table], idx, col);
}

/**
 * mono_metadata_parse_typedef_or_ref:
 * \param m a metadata context.
 * \param ptr a pointer to an encoded TypedefOrRef in \p m
 * \param rptr pointer updated to match the end of the decoded stream
 * \returns a token valid in the \p m metadata decoded from
 * the compressed representation.
 */
guint32
mono_metadata_parse_typedef_or_ref (MonoImage *m, const char *ptr, const char **rptr)
{
        guint32 token;
        token = mono_metadata_decode_value (ptr, &ptr);
        if (rptr)
                *rptr = ptr;
        return mono_metadata_token_from_dor (token);
}

/**
 * mono_metadata_parse_custom_mod:
 * \param m a metadata context.
 * \param dest storage where the info about the custom modifier is stored (may be NULL)
 * \param ptr a pointer to (possibly) the start of a custom modifier list
 * \param rptr pointer updated to match the end of the decoded stream
 *
 * Checks if \p ptr points to a type custom modifier compressed representation.
 *
 * \returns TRUE if a custom modifier was found, FALSE if not.
 */
int
mono_metadata_parse_custom_mod (MonoImage *m, MonoCustomMod *dest, const char *ptr, const char **rptr)
{
        MonoCustomMod local;
        if ((*ptr == MONO_TYPE_CMOD_OPT) || (*ptr == MONO_TYPE_CMOD_REQD)) {
                if (!dest)
                        dest = &local;
                dest->required = *ptr == MONO_TYPE_CMOD_REQD ? 1 : 0;
                dest->token = mono_metadata_parse_typedef_or_ref (m, ptr + 1, rptr);
                return TRUE;
        }
        return FALSE;
}

/*
 * mono_metadata_parse_array_internal:
 * @m: a metadata context.
 * @transient: whenever to allocate data from the heap
 * @ptr: a pointer to an encoded array description.
 * @rptr: pointer updated to match the end of the decoded stream
 *
 * Decodes the compressed array description found in the metadata @m at @ptr.
 *
 * Returns: a #MonoArrayType structure describing the array type
 * and dimensions. Memory is allocated from the heap or from the image mempool, depending
 * on the value of @transient.
 *
 * LOCKING: Acquires the loader lock
 */
static MonoArrayType *
mono_metadata_parse_array_internal (MonoImage *m, MonoGenericContainer *container,
                                                                        gboolean transient, const char *ptr, const char **rptr, MonoError *error)
{
        int i;
        MonoArrayType *array;
        MonoType *etype;
        
        etype = mono_metadata_parse_type_checked (m, container, 0, FALSE, ptr, &ptr, error); //FIXME this doesn't respect @transient
        if (!etype)
                return NULL;

        array = transient ? (MonoArrayType *)g_malloc0 (sizeof (MonoArrayType)) : (MonoArrayType *)mono_image_alloc0 (m, sizeof (MonoArrayType));
        array->eklass = mono_class_from_mono_type_internal (etype);
        array->rank = mono_metadata_decode_value (ptr, &ptr);

        array->numsizes = mono_metadata_decode_value (ptr, &ptr);
        if (array->numsizes)
                array->sizes = transient ? (int *)g_malloc0 (sizeof (int) * array->numsizes) : (int *)mono_image_alloc0 (m, sizeof (int) * array->numsizes);
        for (i = 0; i < array->numsizes; ++i)
                array->sizes [i] = mono_metadata_decode_value (ptr, &ptr);

        array->numlobounds = mono_metadata_decode_value (ptr, &ptr);
        if (array->numlobounds)
                array->lobounds = transient ? (int *)g_malloc0 (sizeof (int) * array->numlobounds) : (int *)mono_image_alloc0 (m, sizeof (int) * array->numlobounds);
        for (i = 0; i < array->numlobounds; ++i)
                array->lobounds [i] = mono_metadata_decode_signed_value (ptr, &ptr);

        if (rptr)
                *rptr = ptr;
        return array;
}

/**
 * mono_metadata_parse_array:
 */
MonoArrayType *
mono_metadata_parse_array (MonoImage *m, const char *ptr, const char **rptr)
{
        ERROR_DECL (error);
        MonoArrayType *ret = mono_metadata_parse_array_internal (m, NULL, FALSE, ptr, rptr, error);
        mono_error_cleanup (error);

        return ret;
}

/**
 * mono_metadata_free_array:
 * \param array array description
 *
 * Frees the array description returned from \c mono_metadata_parse_array.
 */
void
mono_metadata_free_array (MonoArrayType *array)
{
        g_free (array->sizes);
        g_free (array->lobounds);
        g_free (array);
}

/*
 * need to add common field and param attributes combinations:
 * [out] param
 * public static
 * public static literal
 * private
 * private static
 * private static literal
 */
static const MonoType
builtin_types[] = {
        /* data, attrs, type,              nmods, byref, pinned */
        {{NULL}, 0,     MONO_TYPE_VOID,    0,     0,     0},
        {{NULL}, 0,     MONO_TYPE_BOOLEAN, 0,     0,     0},
        {{NULL}, 0,     MONO_TYPE_BOOLEAN, 0,     1,     0},
        {{NULL}, 0,     MONO_TYPE_CHAR,    0,     0,     0},
        {{NULL}, 0,     MONO_TYPE_CHAR,    0,     1,     0},
        {{NULL}, 0,     MONO_TYPE_I1,      0,     0,     0},
        {{NULL}, 0,     MONO_TYPE_I1,      0,     1,     0},
        {{NULL}, 0,     MONO_TYPE_U1,      0,     0,     0},
        {{NULL}, 0,     MONO_TYPE_U1,      0,     1,     0},
        {{NULL}, 0,     MONO_TYPE_I2,      0,     0,     0},
        {{NULL}, 0,     MONO_TYPE_I2,      0,     1,     0},
        {{NULL}, 0,     MONO_TYPE_U2,      0,     0,     0},
        {{NULL}, 0,     MONO_TYPE_U2,      0,     1,     0},
        {{NULL}, 0,     MONO_TYPE_I4,      0,     0,     0},
        {{NULL}, 0,     MONO_TYPE_I4,      0,     1,     0},
        {{NULL}, 0,     MONO_TYPE_U4,      0,     0,     0},
        {{NULL}, 0,     MONO_TYPE_U4,      0,     1,     0},
        {{NULL}, 0,     MONO_TYPE_I8,      0,     0,     0},
        {{NULL}, 0,     MONO_TYPE_I8,      0,     1,     0},
        {{NULL}, 0,     MONO_TYPE_U8,      0,     0,     0},
        {{NULL}, 0,     MONO_TYPE_U8,      0,     1,     0},
        {{NULL}, 0,     MONO_TYPE_R4,      0,     0,     0},
        {{NULL}, 0,     MONO_TYPE_R4,      0,     1,     0},
        {{NULL}, 0,     MONO_TYPE_R8,      0,     0,     0},
        {{NULL}, 0,     MONO_TYPE_R8,      0,     1,     0},
        {{NULL}, 0,     MONO_TYPE_STRING,  0,     0,     0},
        {{NULL}, 0,     MONO_TYPE_STRING,  0,     1,     0},
        {{NULL}, 0,     MONO_TYPE_OBJECT,  0,     0,     0},
        {{NULL}, 0,     MONO_TYPE_OBJECT,  0,     1,     0},
        {{NULL}, 0,     MONO_TYPE_TYPEDBYREF,  0,     0,     0},
        {{NULL}, 0,     MONO_TYPE_I,       0,     0,     0},
        {{NULL}, 0,     MONO_TYPE_I,       0,     1,     0},
        {{NULL}, 0,     MONO_TYPE_U,       0,     0,     0},
        {{NULL}, 0,     MONO_TYPE_U,       0,     1,     0},
};

#define NBUILTIN_TYPES() (sizeof (builtin_types) / sizeof (builtin_types [0]))

static GHashTable *type_cache = NULL;
static gint32 next_generic_inst_id = 0;

/* Protected by image_sets_mutex */
static MonoImageSet *mscorlib_image_set;
/* Protected by image_sets_mutex */
static GPtrArray *image_sets;
static mono_mutex_t image_sets_mutex;

static guint mono_generic_class_hash (gconstpointer data);

/*
 * MonoTypes with modifies are never cached, so we never check or use that field.
 */
static guint
mono_type_hash (gconstpointer data)
{
        const MonoType *type = (const MonoType *) data;
        if (type->type == MONO_TYPE_GENERICINST)
                return mono_generic_class_hash (type->data.generic_class);
        else
                return type->type | (type->byref << 8) | (type->attrs << 9);
}

static gint
mono_type_equal (gconstpointer ka, gconstpointer kb)
{
        const MonoType *a = (const MonoType *) ka;
        const MonoType *b = (const MonoType *) kb;
        
        if (a->type != b->type || a->byref != b->byref || a->attrs != b->attrs || a->pinned != b->pinned)
                return 0;
        /* need other checks */
        return 1;
}

guint
mono_metadata_generic_inst_hash (gconstpointer data)
{
        const MonoGenericInst *ginst = (const MonoGenericInst *) data;
        guint hash = 0;
        int i;
        g_assert (ginst);
        g_assert (ginst->type_argv);
        
        for (i = 0; i < ginst->type_argc; ++i) {
                hash *= 13;
                g_assert (ginst->type_argv [i]);
                hash += mono_metadata_type_hash (ginst->type_argv [i]);
        }

        return hash ^ (ginst->is_open << 8);
}

static gboolean
mono_generic_inst_equal_full (const MonoGenericInst *a, const MonoGenericInst *b, gboolean signature_only)
{
        int i;

        // An optimization: if the ids of two insts are the same, we know they are the same inst and don't check contents.
        // Furthermore, because we perform early de-duping, if the ids differ, we know the contents differ.
#ifndef MONO_SMALL_CONFIG // Optimization does not work in MONO_SMALL_CONFIG: There are no IDs
        if (a->id && b->id) { // "id 0" means "object has no id"-- de-duping hasn't been performed yet, must check contents.
                if (a->id == b->id)
                        return TRUE;
                // In signature-comparison mode id equality implies object equality, but this is not true for inequality.
                // Two separate objects could have signature-equavalent contents.
                if (!signature_only)
                        return FALSE;
        }
#endif

        if (a->is_open != b->is_open || a->type_argc != b->type_argc)
                return FALSE;
        for (i = 0; i < a->type_argc; ++i) {
                if (!do_mono_metadata_type_equal (a->type_argv [i], b->type_argv [i], signature_only))
                        return FALSE;
        }
        return TRUE;
}

gboolean
mono_metadata_generic_inst_equal (gconstpointer ka, gconstpointer kb)
{
        const MonoGenericInst *a = (const MonoGenericInst *) ka;
        const MonoGenericInst *b = (const MonoGenericInst *) kb;

        return mono_generic_inst_equal_full (a, b, FALSE);
}

static guint
mono_generic_class_hash (gconstpointer data)
{
        const MonoGenericClass *gclass = (const MonoGenericClass *) data;
        guint hash = mono_metadata_type_hash (m_class_get_byval_arg (gclass->container_class));

        hash *= 13;
        hash += gclass->is_tb_open;
        hash += mono_metadata_generic_context_hash (&gclass->context);

        return hash;
}

static gboolean
mono_generic_class_equal (gconstpointer ka, gconstpointer kb)
{
        const MonoGenericClass *a = (const MonoGenericClass *) ka;
        const MonoGenericClass *b = (const MonoGenericClass *) kb;

        return _mono_metadata_generic_class_equal (a, b, FALSE);
}

/**
 * mono_metadata_init:
 *
 * Initialize the global variables of this module.
 * This is a Mono runtime internal function.
 */
void
mono_metadata_init (void)
{
        int i;

        /* We guard against double initialization due to how pedump in verification mode works.
        Until runtime initialization is properly factored to work with what it needs we need workarounds like this.
        FIXME: https://bugzilla.xamarin.com/show_bug.cgi?id=58793
        */
        static gboolean inited;

        if (inited)
                return;
        inited = TRUE;

        type_cache = g_hash_table_new (mono_type_hash, mono_type_equal);

        for (i = 0; i < NBUILTIN_TYPES (); ++i)
                g_hash_table_insert (type_cache, (gpointer) &builtin_types [i], (gpointer) &builtin_types [i]);

        mono_os_mutex_init_recursive (&image_sets_mutex);

        mono_counters_register ("ImgSet Cache Hit", MONO_COUNTER_METADATA | MONO_COUNTER_INT, &img_set_cache_hit);
        mono_counters_register ("ImgSet Cache Miss", MONO_COUNTER_METADATA | MONO_COUNTER_INT, &img_set_cache_miss);
        mono_counters_register ("ImgSet Count", MONO_COUNTER_METADATA | MONO_COUNTER_INT, &img_set_count);
}

/**
 * mono_metadata_cleanup:
 *
 * Free all resources used by this module.
 * This is a Mono runtime internal function.
 */
void
mono_metadata_cleanup (void)
{
        g_hash_table_destroy (type_cache);
        type_cache = NULL;
        g_ptr_array_free (image_sets, TRUE);
        image_sets = NULL;
        mono_os_mutex_destroy (&image_sets_mutex);
}

/**
 * mono_metadata_parse_type:
 * \param m metadata context
 * \param mode kind of type that may be found at \p ptr
 * \param opt_attrs optional attributes to store in the returned type
 * \param ptr pointer to the type representation
 * \param rptr pointer updated to match the end of the decoded stream
 * \param transient whenever to allocate the result from the heap or from a mempool
 * 
 * Decode a compressed type description found at \p ptr in \p m .
 * \p mode can be one of \c MONO_PARSE_MOD_TYPE, \c MONO_PARSE_PARAM, \c MONO_PARSE_RET,
 * \c MONO_PARSE_FIELD, \c MONO_PARSE_LOCAL, \c MONO_PARSE_TYPE.
 * This function can be used to decode type descriptions in method signatures,
 * field signatures, locals signatures etc.
 *
 * To parse a generic type, \c generic_container points to the current class'es
 * (the \c generic_container field in the <code>MonoClass</code>) or the current generic method's
 * (stored in <code>image->property_hash</code>) generic container.
 * When we encounter a \c MONO_TYPE_VAR or \c MONO_TYPE_MVAR, it's looked up in
 * this \c MonoGenericContainer.
 *
 * LOCKING: Acquires the loader lock.
 *
 * \returns a \c MonoType structure representing the decoded type.
 */
static MonoType*
mono_metadata_parse_type_internal (MonoImage *m, MonoGenericContainer *container,
                                                                   short opt_attrs, gboolean transient, const char *ptr, const char **rptr, MonoError *error)
{
        MonoType *type, *cached;
        MonoType stype;
        gboolean byref = FALSE;
        gboolean pinned = FALSE;
        const char *tmp_ptr;
        int count = 0; // Number of mod arguments
        gboolean found;

        error_init (error);

        /*
         * According to the spec, custom modifiers should come before the byref
         * flag, but the IL produced by ilasm from the following signature:
         *   object modopt(...) &
         * starts with a byref flag, followed by the modifiers. (bug #49802)
         * Also, this type seems to be different from 'object & modopt(...)'. Maybe
         * it would be better to treat byref as real type constructor instead of
         * a modifier...
         * Also, pinned should come before anything else, but some MSV++ produced
         * assemblies violate this (#bug 61990).
         */

        /* Count the modifiers first */
        tmp_ptr = ptr;
        found = TRUE;
        while (found) {
                switch (*tmp_ptr) {
                case MONO_TYPE_PINNED:
                case MONO_TYPE_BYREF:
                        ++tmp_ptr;
                        break;
                case MONO_TYPE_CMOD_REQD:
                case MONO_TYPE_CMOD_OPT:
                        count ++;
                        mono_metadata_parse_custom_mod (m, NULL, tmp_ptr, &tmp_ptr);
                        break;
                default:
                        found = FALSE;
                }
        }

        MonoCustomModContainer *cmods = NULL;

        if (count) { // There are mods, so the MonoType will be of nonstandard size.
                if (count > 64) {
                        mono_error_set_bad_image (error, m, "Invalid type with more than 64 modifiers");
                        return NULL;
                }

                size_t size = mono_sizeof_type_with_mods (count, FALSE);
                type = transient ? (MonoType *)g_malloc0 (size) : (MonoType *)mono_image_alloc0 (m, size);
                type->has_cmods = TRUE;

                cmods = mono_type_get_cmods (type);
                cmods->count = count;
                cmods->image = m;
        } else {     // The type is of standard size, so we can allocate it on the stack.
                type = &stype;
                memset (type, 0, MONO_SIZEOF_TYPE);
        }

        /* Iterate again, but now parse pinned, byref and custom modifiers */
        found = TRUE;
        /* cmods are encoded in reverse order from how we normally see them.
         * "int32 modopt (Foo) modopt (Bar)" is encoded as "cmod_opt [typedef_or_ref "Bar"] cmod_opt [typedef_or_ref "Foo"] I4"
         */
        while (found) {
                switch (*ptr) {
                case MONO_TYPE_PINNED:
                        pinned = TRUE;
                        ++ptr;
                        break;
                case MONO_TYPE_BYREF:
                        byref = TRUE;
                        ++ptr;
                        break;
                case MONO_TYPE_CMOD_REQD:
                case MONO_TYPE_CMOD_OPT:
                        mono_metadata_parse_custom_mod (m, &(cmods->modifiers [--count]), ptr, &ptr);
                        break;
                default:
                        found = FALSE;
                }
        }
        
        // either there were no cmods, or else we iterated through all of cmods backwards to populate it.
        g_assert (count == 0);

        type->attrs = opt_attrs;
        type->byref = byref;
        type->pinned = pinned ? 1 : 0;

        if (!do_mono_metadata_parse_type (type, m, container, transient, ptr, &ptr, error))
                return NULL;

        if (rptr)
                *rptr = ptr;

        // Possibly we can return an already-allocated type instead of the one we decoded
        if (!type->has_cmods && !transient) {
                /* no need to free type here, because it is on the stack */
                if ((type->type == MONO_TYPE_CLASS || type->type == MONO_TYPE_VALUETYPE) && !type->pinned && !type->attrs) {
                        MonoType *ret = type->byref ? m_class_get_this_arg (type->data.klass) : m_class_get_byval_arg (type->data.klass);

                        /* Consider the case:

                             class Foo<T> { class Bar {} }
                             class Test : Foo<Test>.Bar {}

                           When Foo<Test> is being expanded, 'Test' isn't yet initialized.  It's actually in
                           a really pristine state: it doesn't even know whether 'Test' is a reference or a value type.

                           We ensure that the MonoClass is in a state that we can canonicalize to:

                             klass->_byval_arg.data.klass == klass
                             klass->this_arg.data.klass == klass

                           If we can't canonicalize 'type', it doesn't matter, since later users of 'type' will do it.

                           LOCKING: even though we don't explicitly hold a lock, in the problematic case 'ret' is a field
                                    of a MonoClass which currently holds the loader lock.  'type' is local.
                        */
                        if (ret->data.klass == type->data.klass) {
                                return ret;
                        }
                }
                /* No need to use locking since nobody is modifying the hash table */
                if ((cached = (MonoType *)g_hash_table_lookup (type_cache, type))) {
                        return cached;
                }
        }
        
        /* printf ("%x %x %c %s\n", type->attrs, type->num_mods, type->pinned ? 'p' : ' ', mono_type_full_name (type)); */
        
        if (type == &stype) { // Type was allocated on the stack, so we need to copy it to safety
                type = transient ? (MonoType *)g_malloc (MONO_SIZEOF_TYPE) : (MonoType *)mono_image_alloc (m, MONO_SIZEOF_TYPE);
                memcpy (type, &stype, MONO_SIZEOF_TYPE);
        }
        return type;
}


MonoType*
mono_metadata_parse_type_checked (MonoImage *m, MonoGenericContainer *container,
                                                           short opt_attrs, gboolean transient, const char *ptr, const char **rptr, MonoError *error)
{
        return mono_metadata_parse_type_internal (m, container, opt_attrs, transient, ptr, rptr, error);
}

/*
 * LOCKING: Acquires the loader lock.
 */
MonoType*
mono_metadata_parse_type (MonoImage *m, MonoParseTypeMode mode, short opt_attrs,
                          const char *ptr, const char **rptr)
{
        ERROR_DECL (error);
        MonoType * type = mono_metadata_parse_type_internal (m, NULL, opt_attrs, FALSE, ptr, rptr, error);
        mono_error_cleanup (error);
        return type;
}

gboolean
mono_metadata_method_has_param_attrs (MonoImage *m, int def)
{
        MonoTableInfo *paramt = &m->tables [MONO_TABLE_PARAM];
        MonoTableInfo *methodt = &m->tables [MONO_TABLE_METHOD];
        guint lastp, i, param_index = mono_metadata_decode_row_col (methodt, def - 1, MONO_METHOD_PARAMLIST);

        if (def < methodt->rows)
                lastp = mono_metadata_decode_row_col (methodt, def, MONO_METHOD_PARAMLIST);
        else
                lastp = m->tables [MONO_TABLE_PARAM].rows + 1;

        for (i = param_index; i < lastp; ++i) {
                guint32 flags = mono_metadata_decode_row_col (paramt, i - 1, MONO_PARAM_FLAGS);
                if (flags)
                        return TRUE;
        }

        return FALSE;
}

/*
 * mono_metadata_get_param_attrs:
 *
 * @m The image to loader parameter attributes from
 * @def method def token (one based)
 * @param_count number of params to decode including the return value
 *
 *   Return the parameter attributes for the method whose MethodDef index is DEF. The 
 * returned memory needs to be freed by the caller. If all the param attributes are
 * 0, then NULL is returned.
 */
int*
mono_metadata_get_param_attrs (MonoImage *m, int def, int param_count)
{
        MonoTableInfo *paramt = &m->tables [MONO_TABLE_PARAM];
        MonoTableInfo *methodt = &m->tables [MONO_TABLE_METHOD];
        guint32 cols [MONO_PARAM_SIZE];
        guint lastp, i, param_index = mono_metadata_decode_row_col (methodt, def - 1, MONO_METHOD_PARAMLIST);
        int *pattrs = NULL;

        if (def < methodt->rows)
                lastp = mono_metadata_decode_row_col (methodt, def, MONO_METHOD_PARAMLIST);
        else
                lastp = paramt->rows + 1;

        for (i = param_index; i < lastp; ++i) {
                mono_metadata_decode_row (paramt, i - 1, cols, MONO_PARAM_SIZE);
                if (cols [MONO_PARAM_FLAGS]) {
                        if (!pattrs)
                                pattrs = g_new0 (int, param_count);
                        /* at runtime we just ignore this kind of malformed file:
                        * the verifier can signal the error to the user
                        */
                        if (cols [MONO_PARAM_SEQUENCE] >= param_count)
                                continue;
                        pattrs [cols [MONO_PARAM_SEQUENCE]] = cols [MONO_PARAM_FLAGS];
                }
        }

        return pattrs;
}


/**
 * mono_metadata_parse_signature:
 * \param image metadata context
 * \param token metadata token
 *
 * Decode a method signature stored in the \c StandAloneSig table
 *
 * \returns a \c MonoMethodSignature describing the signature.
 */
MonoMethodSignature*
mono_metadata_parse_signature (MonoImage *image, guint32 token)
{
        ERROR_DECL (error);
        MonoMethodSignature *ret;
        ret = mono_metadata_parse_signature_checked (image, token, error);
        mono_error_cleanup (error);
        return ret;
}

/*
 * mono_metadata_parse_signature_checked:
 * @image: metadata context
 * @token: metadata token
 * @error: set on error
 *
 * Decode a method signature stored in the STANDALONESIG table
 *
 * Returns: a MonoMethodSignature describing the signature. On failure
 * returns NULL and sets @error.
 */
MonoMethodSignature*
mono_metadata_parse_signature_checked (MonoImage *image, guint32 token, MonoError *error)
{

        error_init (error);
        MonoTableInfo *tables = image->tables;
        guint32 idx = mono_metadata_token_index (token);
        guint32 sig;
        const char *ptr;

        if (image_is_dynamic (image)) {
                return (MonoMethodSignature *)mono_lookup_dynamic_token (image, token, NULL, error);
        }

        g_assert (mono_metadata_token_table(token) == MONO_TABLE_STANDALONESIG);
                
        sig = mono_metadata_decode_row_col (&tables [MONO_TABLE_STANDALONESIG], idx - 1, 0);

        ptr = mono_metadata_blob_heap (image, sig);
        mono_metadata_decode_blob_size (ptr, &ptr);

        return mono_metadata_parse_method_signature_full (image, NULL, 0, ptr, NULL, error);
}

/**
 * mono_metadata_signature_alloc:
 * \param image metadata context
 * \param nparams number of parameters in the signature
 *
 * Allocate a \c MonoMethodSignature structure with the specified number of params.
 * The return type and the params types need to be filled later.
 * This is a Mono runtime internal function.
 *
 * LOCKING: Assumes the loader lock is held.
 *
 * \returns the new \c MonoMethodSignature structure.
 */
MonoMethodSignature*
mono_metadata_signature_alloc (MonoImage *m, guint32 nparams)
{
        MonoMethodSignature *sig;

        sig = (MonoMethodSignature *)mono_image_alloc0 (m, MONO_SIZEOF_METHOD_SIGNATURE + ((gint32)nparams) * sizeof (MonoType*));
        sig->param_count = nparams;
        sig->sentinelpos = -1;

        return sig;
}

static MonoMethodSignature*
mono_metadata_signature_dup_internal_with_padding (MonoImage *image, MonoMemPool *mp, MonoMethodSignature *sig, size_t padding)
{
        int sigsize, sig_header_size;
        MonoMethodSignature *ret;
        sigsize = sig_header_size = MONO_SIZEOF_METHOD_SIGNATURE + sig->param_count * sizeof (MonoType *) + padding;
        if (sig->ret)
                sigsize += mono_sizeof_type (sig->ret);

        if (image) {
                ret = (MonoMethodSignature *)mono_image_alloc (image, sigsize);
        } else if (mp) {
                ret = (MonoMethodSignature *)mono_mempool_alloc (mp, sigsize);
        } else {
                ret = (MonoMethodSignature *)g_malloc (sigsize);
        }

        memcpy (ret, sig, sig_header_size - padding);

        // Copy return value because of ownership semantics.
        if (sig->ret) {
                // Danger! Do not alter padding use without changing the dup_add_this below
                intptr_t end_of_header = (intptr_t)( (char*)(ret) + sig_header_size);
                ret->ret = (MonoType *)end_of_header;
                memcpy (ret->ret, sig->ret, mono_sizeof_type (sig->ret));
        }

        return ret;
}

static MonoMethodSignature*
mono_metadata_signature_dup_internal (MonoImage *image, MonoMemPool *mp, MonoMethodSignature *sig)
{
        return mono_metadata_signature_dup_internal_with_padding (image, mp, sig, 0);
}
/*
 * signature_dup_add_this:
 *
 *  Make a copy of @sig, adding an explicit this argument.
 */
MonoMethodSignature*
mono_metadata_signature_dup_add_this (MonoImage *image, MonoMethodSignature *sig, MonoClass *klass)
{
        MonoMethodSignature *ret;
        ret = mono_metadata_signature_dup_internal_with_padding (image, NULL, sig, sizeof (MonoType *));

        ret->param_count = sig->param_count + 1;
        ret->hasthis = FALSE;

        for (int i = sig->param_count - 1; i >= 0; i --)
                ret->params [i + 1] = sig->params [i];
        ret->params [0] = m_class_is_valuetype (klass) ? m_class_get_this_arg (klass) : m_class_get_byval_arg (klass);

        for (int i = sig->param_count - 1; i >= 0; i --)
                g_assert(ret->params [i + 1]->type == sig->params [i]->type && ret->params [i+1]->type != MONO_TYPE_END);
        g_assert (ret->ret->type == sig->ret->type && ret->ret->type != MONO_TYPE_END);

        return ret;
}



MonoMethodSignature*
mono_metadata_signature_dup_full (MonoImage *image, MonoMethodSignature *sig)
{
        MonoMethodSignature *ret = mono_metadata_signature_dup_internal (image, NULL, sig);

        for (int i = 0 ; i < sig->param_count; i ++)
                g_assert(ret->params [i]->type == sig->params [i]->type);
        g_assert (ret->ret->type == sig->ret->type);

        return ret;
}

/*The mempool is accessed without synchronization*/
MonoMethodSignature*
mono_metadata_signature_dup_mempool (MonoMemPool *mp, MonoMethodSignature *sig)
{
        return mono_metadata_signature_dup_internal (NULL, mp, sig);
}

/**
 * mono_metadata_signature_dup:
 * \param sig method signature
 *
 * Duplicate an existing \c MonoMethodSignature so it can be modified.
 * This is a Mono runtime internal function.
 *
 * \returns the new \c MonoMethodSignature structure.
 */
MonoMethodSignature*
mono_metadata_signature_dup (MonoMethodSignature *sig)
{
        return mono_metadata_signature_dup_full (NULL, sig);
}

/*
 * mono_metadata_signature_size:
 *
 *   Return the amount of memory allocated to SIG.
 */
guint32
mono_metadata_signature_size (MonoMethodSignature *sig)
{
        return MONO_SIZEOF_METHOD_SIGNATURE + sig->param_count * sizeof (MonoType *);
}

/**
 * mono_metadata_parse_method_signature_full:
 * \param m metadata context
 * \param generic_container: generics container
 * \param def the \c MethodDef index or 0 for \c Ref signatures.
 * \param ptr pointer to the signature metadata representation
 * \param rptr pointer updated to match the end of the decoded stream
 * \param error set on error
 *
 *
 * Decode a method signature stored at \p ptr.
 * This is a Mono runtime internal function.
 *
 * LOCKING: Assumes the loader lock is held.
 *
 * \returns a \c MonoMethodSignature describing the signature.  On error sets
 * \p error and returns \c NULL.
 */
MonoMethodSignature *
mono_metadata_parse_method_signature_full (MonoImage *m, MonoGenericContainer *container,
                                           int def, const char *ptr, const char **rptr, MonoError *error)
{
        MonoMethodSignature *method;
        int i, *pattrs = NULL;
        guint32 hasthis = 0, explicit_this = 0, call_convention, param_count;
        guint32 gen_param_count = 0;
        gboolean is_open = FALSE;

        error_init (error);

        if (*ptr & 0x10)
                gen_param_count = 1;
        if (*ptr & 0x20)
                hasthis = 1;
        if (*ptr & 0x40)
                explicit_this = 1;
        call_convention = *ptr & 0x0F;
        ptr++;
        if (gen_param_count)
                gen_param_count = mono_metadata_decode_value (ptr, &ptr);
        param_count = mono_metadata_decode_value (ptr, &ptr);

        if (def)
                pattrs = mono_metadata_get_param_attrs (m, def, param_count + 1); /*Must be + 1 since signature's param count doesn't account for the return value */

        method = mono_metadata_signature_alloc (m, param_count);
        method->hasthis = hasthis;
        method->explicit_this = explicit_this;
        method->call_convention = call_convention;
        method->generic_param_count = gen_param_count;

        switch (method->call_convention) {
        case MONO_CALL_DEFAULT:
        case MONO_CALL_VARARG:
                method->pinvoke = 0;
                break;
        case MONO_CALL_C:
        case MONO_CALL_STDCALL:
        case MONO_CALL_THISCALL:
        case MONO_CALL_FASTCALL:
                method->pinvoke = 1;
                break;
        }

        if (call_convention != 0xa) {
                method->ret = mono_metadata_parse_type_checked (m, container, pattrs ? pattrs [0] : 0, FALSE, ptr, &ptr, error);
                if (!method->ret) {
                        mono_metadata_free_method_signature (method);
                        g_free (pattrs);
                        return NULL;
                }
                is_open = mono_class_is_open_constructed_type (method->ret);
        }

        for (i = 0; i < method->param_count; ++i) {
                if (*ptr == MONO_TYPE_SENTINEL) {
                        if (method->call_convention != MONO_CALL_VARARG || def) {
                                mono_error_set_bad_image (error, m, "Found sentinel for methoddef or no vararg");
                                g_free (pattrs);
                                return NULL;
                        }
                        if (method->sentinelpos >= 0) {
                                mono_error_set_bad_image (error, m, "Found sentinel twice in the same signature.");
                                g_free (pattrs);
                                return NULL;
                        }
                        method->sentinelpos = i;
                        ptr++;
                }
                method->params [i] = mono_metadata_parse_type_checked (m, container, pattrs ? pattrs [i+1] : 0, FALSE, ptr, &ptr, error);
                if (!method->params [i]) {
                        mono_metadata_free_method_signature (method);
                        g_free (pattrs);
                        return NULL;
                }
                if (!is_open)
                        is_open = mono_class_is_open_constructed_type (method->params [i]);
        }

        /* The sentinel could be missing if the caller does not pass any additional arguments */
        if (!def && method->call_convention == MONO_CALL_VARARG && method->sentinelpos < 0)
                method->sentinelpos = method->param_count;

        method->has_type_parameters = is_open;

        if (def && (method->call_convention == MONO_CALL_VARARG))
                method->sentinelpos = method->param_count;

        g_free (pattrs);

        if (rptr)
                *rptr = ptr;
        /*
         * Add signature to a cache and increase ref count...
         */

        return method;
}

/**
 * mono_metadata_parse_method_signature:
 * \param m metadata context
 * \param def the \c MethodDef index or 0 for \c Ref signatures.
 * \param ptr pointer to the signature metadata representation
 * \param rptr pointer updated to match the end of the decoded stream
 *
 * Decode a method signature stored at \p ptr.
 * This is a Mono runtime internal function.
 *
 * LOCKING: Assumes the loader lock is held.
 *
 * \returns a \c MonoMethodSignature describing the signature.
 */
MonoMethodSignature *
mono_metadata_parse_method_signature (MonoImage *m, int def, const char *ptr, const char **rptr)
{
        /*
         * This function MUST NOT be called by runtime code as it does error handling incorrectly.
         * Use mono_metadata_parse_method_signature_full instead.
         * It's ok to asser on failure as we no longer use it.
         */
        ERROR_DECL (error);
        MonoMethodSignature *ret;
        ret = mono_metadata_parse_method_signature_full (m, NULL, def, ptr, rptr, error);
        mono_error_assert_ok (error);

        return ret;
}

/**
 * mono_metadata_free_method_signature:
 * \param sig signature to destroy
 *
 * Free the memory allocated in the signature \p sig.
 * This method needs to be robust and work also on partially-built
 * signatures, so it does extra checks.
 */
void
mono_metadata_free_method_signature (MonoMethodSignature *sig)
{
        /* Everything is allocated from mempools */
        /*
        int i;
        if (sig->ret)
                mono_metadata_free_type (sig->ret);
        for (i = 0; i < sig->param_count; ++i) {
                if (sig->params [i])
                        mono_metadata_free_type (sig->params [i]);
        }
        */
}

void
mono_metadata_free_inflated_signature (MonoMethodSignature *sig)
{
        int i;

        /* Allocated in inflate_generic_signature () */
        if (sig->ret)
                mono_metadata_free_type (sig->ret);
        for (i = 0; i < sig->param_count; ++i) {
                if (sig->params [i])
                        mono_metadata_free_type (sig->params [i]);
        }
        g_free (sig);
}

static gboolean
inflated_method_equal (gconstpointer a, gconstpointer b)
{
        const MonoMethodInflated *ma = (const MonoMethodInflated *)a;
        const MonoMethodInflated *mb = (const MonoMethodInflated *)b;
        if (ma->declaring != mb->declaring)
                return FALSE;
        return mono_metadata_generic_context_equal (&ma->context, &mb->context);
}

static guint
inflated_method_hash (gconstpointer a)
{
        const MonoMethodInflated *ma = (const MonoMethodInflated *)a;
        return (mono_metadata_generic_context_hash (&ma->context) ^ mono_aligned_addr_hash (ma->declaring));
}

static gboolean
inflated_signature_equal (gconstpointer a, gconstpointer b)
{
        const MonoInflatedMethodSignature *sig1 = (const MonoInflatedMethodSignature *)a;
        const MonoInflatedMethodSignature *sig2 = (const MonoInflatedMethodSignature *)b;

        /* sig->sig is assumed to be canonized */
        if (sig1->sig != sig2->sig)
                return FALSE;
        /* The generic instances are canonized */
        return mono_metadata_generic_context_equal (&sig1->context, &sig2->context);
}

static guint
inflated_signature_hash (gconstpointer a)
{
        const MonoInflatedMethodSignature *sig = (const MonoInflatedMethodSignature *)a;

        /* sig->sig is assumed to be canonized */
        return mono_metadata_generic_context_hash (&sig->context) ^ mono_aligned_addr_hash (sig->sig);
}

/*static void
dump_ginst (MonoGenericInst *ginst)
{
        int i;
        char *name;

        g_print ("Ginst: <");
        for (i = 0; i < ginst->type_argc; ++i) {
                if (i != 0)
                        g_print (", ");
                name = mono_type_get_name (ginst->type_argv [i]);
                g_print ("%s", name);
                g_free (name);
        }
        g_print (">");
}*/

static gboolean
aggregate_modifiers_equal (gconstpointer ka, gconstpointer kb)
{
        MonoAggregateModContainer *amods1 = (MonoAggregateModContainer *)ka;
        MonoAggregateModContainer *amods2 = (MonoAggregateModContainer *)kb;
        if (amods1->count != amods2->count)
                return FALSE;
        for (int i = 0; i < amods1->count; ++i) {
                if (amods1->modifiers [i].required != amods2->modifiers [i].required)
                        return FALSE;
                if (!mono_metadata_type_equal_full (amods1->modifiers [i].type, amods2->modifiers [i].type, TRUE))
                        return FALSE;
        }
        return TRUE;
}

static guint
aggregate_modifiers_hash (gconstpointer a)
{
        const MonoAggregateModContainer *amods = (const MonoAggregateModContainer *)a;
        guint hash = 0;
        for (int i = 0; i < amods->count; ++i)
        {
                // hash details borrowed from mono_metadata_generic_inst_hash
                hash *= 13;
                hash ^= (amods->modifiers [i].required << 8);
                hash += mono_metadata_type_hash (amods->modifiers [i].type);
        }

        return hash;
}

static gboolean type_in_image (MonoType *type, MonoImage *image);
static gboolean aggregate_modifiers_in_image (MonoAggregateModContainer *amods, MonoImage *image);

static gboolean
signature_in_image (MonoMethodSignature *sig, MonoImage *image)
{
        gpointer iter = NULL;
        MonoType *p;

        while ((p = mono_signature_get_params (sig, &iter)) != NULL)
                if (type_in_image (p, image))
                        return TRUE;

        return type_in_image (mono_signature_get_return_type (sig), image);
}

static gboolean
ginst_in_image (MonoGenericInst *ginst, MonoImage *image)
{
        int i;

        for (i = 0; i < ginst->type_argc; ++i) {
                if (type_in_image (ginst->type_argv [i], image))
                        return TRUE;
        }

        return FALSE;
}

static gboolean
gclass_in_image (MonoGenericClass *gclass, MonoImage *image)
{
        return m_class_get_image (gclass->container_class) == image ||
                ginst_in_image (gclass->context.class_inst, image);
}

static gboolean
type_in_image (MonoType *type, MonoImage *image)
{
retry:
        if (type->has_cmods && mono_type_is_aggregate_mods (type))
                if (aggregate_modifiers_in_image (mono_type_get_amods (type), image))
                        return TRUE;

        switch (type->type) {
        case MONO_TYPE_GENERICINST:
                return gclass_in_image (type->data.generic_class, image);
        case MONO_TYPE_PTR:
                type = type->data.type;
                goto retry;
        case MONO_TYPE_SZARRAY:
                type = m_class_get_byval_arg (type->data.klass);
                goto retry;
        case MONO_TYPE_ARRAY:
                type = m_class_get_byval_arg (type->data.array->eklass);
                goto retry;
        case MONO_TYPE_FNPTR:
                return signature_in_image (type->data.method, image);
        case MONO_TYPE_VAR:
        case MONO_TYPE_MVAR:
                if (image == mono_get_image_for_generic_param (type->data.generic_param))
                        return TRUE;
                else if (type->data.generic_param->gshared_constraint) {
                        type = type->data.generic_param->gshared_constraint;
                        goto retry;
                }
                return FALSE;
        default:
                /* At this point, we should've avoided all potential allocations in mono_class_from_mono_type_internal () */
                return image == m_class_get_image (mono_class_from_mono_type_internal (type));
        }
}

gboolean
mono_type_in_image (MonoType *type, MonoImage *image)
{
        return type_in_image (type, image);
}

gboolean
aggregate_modifiers_in_image (MonoAggregateModContainer *amods, MonoImage *image)
{
        for (int i = 0; i < amods->count; i++)
                if (type_in_image (amods->modifiers [i].type, image))
                        return TRUE;
        return FALSE;
}

static void
image_sets_lock (void)
{
        mono_os_mutex_lock (&image_sets_mutex);
}

static void
image_sets_unlock (void)
{
        mono_os_mutex_unlock (&image_sets_mutex);
}

//1103, 1327, 1597
#define HASH_TABLE_SIZE 1103
static MonoImageSet *img_set_cache [HASH_TABLE_SIZE];

static guint32
mix_hash (uintptr_t source)
{
        unsigned int hash = source;

        // Actual hash
        hash = (((hash * 215497) >> 16) ^ ((hash * 1823231) + hash));

        // Mix in highest bits on 64-bit systems only
        if (sizeof (source) > 4)
                hash = hash ^ ((source >> 31) >> 1);

        return hash;
}

static guint32
hash_images (MonoImage **images, int nimages)
{
        guint32 res = 0;
        int i;
        for (i = 0; i < nimages; ++i)
                res += mix_hash ((size_t)images [i]);

        return res;
}

static gboolean
compare_img_set (MonoImageSet *set, MonoImage **images, int nimages)
{
        int j, k;

        if (set->nimages != nimages)
                return FALSE;

        for (j = 0; j < nimages; ++j) {
                for (k = 0; k < nimages; ++k)
                        if (set->images [k] == images [j])
                                break; // Break on match

                // If we iterated all the way through set->images, images[j] was *not* found.
                if (k == nimages)
                        break; // Break on "image not found"
        }

        // If we iterated all the way through images without breaking, all items in images were found in set->images
        return j == nimages;
}


static MonoImageSet*
img_set_cache_get (MonoImage **images, int nimages)
{
        guint32 hash_code = hash_images (images, nimages);
        int index = hash_code % HASH_TABLE_SIZE;
        MonoImageSet *img = img_set_cache [index];
        if (!img || !compare_img_set (img, images, nimages)) {
                UnlockedIncrement (&img_set_cache_miss);
                return NULL;
        }
        UnlockedIncrement (&img_set_cache_hit);
        return img;
}

static void
img_set_cache_add (MonoImageSet *set)
{
        guint32 hash_code = hash_images (set->images, set->nimages);
        int index = hash_code % HASH_TABLE_SIZE;
        img_set_cache [index] = set;    
}

static void
img_set_cache_remove (MonoImageSet *is)
{
        guint32 hash_code = hash_images (is->images, is->nimages);
        int index = hash_code % HASH_TABLE_SIZE;
        if (img_set_cache [index] == is)
                img_set_cache [index] = NULL;
}
/*
 * get_image_set:
 *
 *   Return a MonoImageSet representing the set of images in IMAGES.
 */
static MonoImageSet*
get_image_set (MonoImage **images, int nimages)
{
        int i, j, k;
        MonoImageSet *set;
        GSList *l;

        /* Common case: Image set contains corlib only. If we've seen that case before, we cached the set. */
        if (nimages == 1 && images [0] == mono_defaults.corlib && mscorlib_image_set)
                return mscorlib_image_set;

        /* Happens with empty generic instances */
        // FIXME: Is corlib the correct thing to return here? If so, why? This may be an artifact of generic instances previously defaulting to allocating from corlib.
        if (nimages == 0)
                return mscorlib_image_set;

        set = img_set_cache_get (images, nimages);
        if (set)
                return set;

        image_sets_lock ();

        if (!image_sets)
                image_sets = g_ptr_array_new ();

        // Before we go on, we should check to see whether a MonoImageSet with these images already exists.
        // We can search the referred-by imagesets of any one of our images to do this. Arbitrarily pick one here:
        if (images [0] == mono_defaults.corlib && nimages > 1)
                l = images [1]->image_sets; // Prefer not to search the imagesets of corlib-- that will be a long list.
        else
                l = images [0]->image_sets;

        set = NULL;
        while (l) // Iterate over selected list, looking for an imageset with members equal to our target one
        {
                set = (MonoImageSet *)l->data;

                if (set->nimages == nimages) { // Member count differs, this can't be it
                        // Compare all members to all members-- order might be different
                        for (j = 0; j < nimages; ++j) {
                                for (k = 0; k < nimages; ++k)
                                        if (set->images [k] == images [j])
                                                break; // Break on match

                                // If we iterated all the way through set->images, images[j] was *not* found.
                                if (k == nimages)
                                        break; // Break on "image not found"
                        }

                        // If we iterated all the way through images without breaking, all items in images were found in set->images
                        if (j == nimages) {
                                // Break on "found a set with equal members".
                                // This happens in case of a hash collision with a previously cached set.
                                break;
                        }
                }

                l = l->next;
        }

        // If we iterated all the way through l without breaking, the imageset does not already exist and we should create it
        if (!l) {
                set = g_new0 (MonoImageSet, 1);
                set->nimages = nimages;
                set->images = g_new0 (MonoImage*, nimages);
                mono_os_mutex_init_recursive (&set->lock);
                for (i = 0; i < nimages; ++i)
                        set->images [i] = images [i];
                set->gclass_cache = mono_conc_hashtable_new_full (mono_generic_class_hash, mono_generic_class_equal, NULL, (GDestroyNotify)free_generic_class);
                set->ginst_cache = g_hash_table_new_full (mono_metadata_generic_inst_hash, mono_metadata_generic_inst_equal, NULL, (GDestroyNotify)free_generic_inst);
                set->gmethod_cache = g_hash_table_new_full (inflated_method_hash, inflated_method_equal, NULL, (GDestroyNotify)free_inflated_method);
                set->gsignature_cache = g_hash_table_new_full (inflated_signature_hash, inflated_signature_equal, NULL, (GDestroyNotify)free_inflated_signature);

                set->szarray_cache = g_hash_table_new_full (mono_aligned_addr_hash, NULL, NULL, NULL);
                set->array_cache = g_hash_table_new_full (mono_aligned_addr_hash, NULL, NULL, NULL);

                set->aggregate_modifiers_cache = g_hash_table_new_full (aggregate_modifiers_hash, aggregate_modifiers_equal, NULL, (GDestroyNotify)free_aggregate_modifiers);

                for (i = 0; i < nimages; ++i)
                        set->images [i]->image_sets = g_slist_prepend (set->images [i]->image_sets, set);

                g_ptr_array_add (image_sets, set);
                UnlockedIncrement (&img_set_count); /* locked by image_sets_lock () */
        }

        /* Cache the set. If there was a cache collision, the previously cached value will be replaced. */
        img_set_cache_add (set);

        if (nimages == 1 && images [0] == mono_defaults.corlib) {
                mono_memory_barrier ();
                mscorlib_image_set = set;
        }

        image_sets_unlock ();

        return set;
}

static void
delete_image_set (MonoImageSet *set)
{
        int i;

        mono_conc_hashtable_destroy (set->gclass_cache);
        g_hash_table_destroy (set->ginst_cache);
        g_hash_table_destroy (set->gmethod_cache);
        g_hash_table_destroy (set->gsignature_cache);

        g_hash_table_destroy (set->szarray_cache);
        g_hash_table_destroy (set->array_cache);
        if (set->ptr_cache)
                g_hash_table_destroy (set->ptr_cache);

        g_hash_table_destroy (set->aggregate_modifiers_cache);

        for (i = 0; i < set->gshared_types_len; ++i) {
                if (set->gshared_types [i])
                        g_hash_table_destroy (set->gshared_types [i]);
        }
        g_free (set->gshared_types);

        mono_wrapper_caches_free (&set->wrapper_caches);

        image_sets_lock ();

        for (i = 0; i < set->nimages; ++i)
                set->images [i]->image_sets = g_slist_remove (set->images [i]->image_sets, set);

        g_ptr_array_remove (image_sets, set);

        image_sets_unlock ();

        img_set_cache_remove (set);

        if (set->mempool)
                mono_mempool_destroy (set->mempool);
        g_free (set->images);
        mono_os_mutex_destroy (&set->lock);
        g_free (set);
}

void
mono_image_set_lock (MonoImageSet *set)
{
        mono_os_mutex_lock (&set->lock);
}

void
mono_image_set_unlock (MonoImageSet *set)
{
        mono_os_mutex_unlock (&set->lock);
}

gpointer
mono_image_set_alloc (MonoImageSet *set, guint size)
{
        gpointer res;

        mono_image_set_lock (set);
        if (!set->mempool)
                set->mempool = mono_mempool_new_size (INITIAL_IMAGE_SET_SIZE);
        res = mono_mempool_alloc (set->mempool, size);
        mono_image_set_unlock (set);

        return res;
}

gpointer
mono_image_set_alloc0 (MonoImageSet *set, guint size)
{
        gpointer res;

        mono_image_set_lock (set);
        if (!set->mempool)
                set->mempool = mono_mempool_new_size (INITIAL_IMAGE_SET_SIZE);
        res = mono_mempool_alloc0 (set->mempool, size);
        mono_image_set_unlock (set);

        return res;
}

char*
mono_image_set_strdup (MonoImageSet *set, const char *s)
{
        char *res;

        mono_image_set_lock (set);
        if (!set->mempool)
                set->mempool = mono_mempool_new_size (INITIAL_IMAGE_SET_SIZE);
        res = mono_mempool_strdup (set->mempool, s);
        mono_image_set_unlock (set);

        return res;
}

// Get a descriptive string for a MonoImageSet
// Callers are obligated to free buffer with g_free after use
char *
mono_image_set_description (MonoImageSet *set)
{
        GString *result = g_string_new (NULL);
        int img;
        g_string_append (result, "[");
        for (img = 0; img < set->nimages; img++)
        {
                if (img > 0)
                        g_string_append (result, ", ");
                g_string_append (result, set->images[img]->name);
        }
        g_string_append (result, "]");
        return g_string_free (result, FALSE);
}

/* 
 * Structure used by the collect_..._images functions to store the image list.
 */
typedef struct {
        MonoImage *image_buf [64];
        MonoImage **images;
        int nimages, images_len;
} CollectData;

static void
collect_data_init (CollectData *data)
{
        data->images = data->image_buf;
        data->images_len = 64;
        data->nimages = 0;
}

static void
collect_data_free (CollectData *data)
{
        if (data->images != data->image_buf)
                g_free (data->images);
}

static void
enlarge_data (CollectData *data)
{
        int new_len = data->images_len < 16 ? 16 : data->images_len * 2;
        MonoImage **d = g_new (MonoImage *, new_len);

        // FIXME: test this
        g_assert_not_reached ();
        memcpy (d, data->images, data->images_len);
        if (data->images != data->image_buf)
                g_free (data->images);
        data->images = d;
        data->images_len = new_len;
}

static void
add_image (MonoImage *image, CollectData *data)
{
        int i;

        /* The arrays are small, so use a linear search instead of a hash table */
        for (i = 0; i < data->nimages; ++i)
                if (data->images [i] == image)
                        return;

        if (data->nimages == data->images_len)
                enlarge_data (data);

        data->images [data->nimages ++] = image;
}

static void
collect_type_images (MonoType *type, CollectData *data);

static void
collect_ginst_images (MonoGenericInst *ginst, CollectData *data)
{
        int i;

        for (i = 0; i < ginst->type_argc; ++i) {
                collect_type_images (ginst->type_argv [i], data);
        }
}

static void
collect_gclass_images (MonoGenericClass *gclass, CollectData *data)
{
        add_image (m_class_get_image (gclass->container_class), data);
        if (gclass->context.class_inst)
                collect_ginst_images (gclass->context.class_inst, data);
}

static void
collect_signature_images (MonoMethodSignature *sig, CollectData *data)
{
        gpointer iter = NULL;
        MonoType *p;

        collect_type_images (mono_signature_get_return_type (sig), data);
        while ((p = mono_signature_get_params (sig, &iter)) != NULL)
                collect_type_images (p, data);
}

static void
collect_inflated_signature_images (MonoInflatedMethodSignature *sig, CollectData *data)
{
        collect_signature_images (sig->sig, data);
        if (sig->context.class_inst)
                collect_ginst_images (sig->context.class_inst, data);
        if (sig->context.method_inst)
                collect_ginst_images (sig->context.method_inst, data);
}

static void
collect_method_images (MonoMethodInflated *method, CollectData *data)
{
        MonoMethod *m = method->declaring;

        add_image (m_class_get_image (method->declaring->klass), data);
        if (method->context.class_inst)
                collect_ginst_images (method->context.class_inst, data);
        if (method->context.method_inst)
                collect_ginst_images (method->context.method_inst, data);
        /*
         * Dynamic assemblies have no references, so the images they depend on can be unloaded before them.
         */
        if (image_is_dynamic (m_class_get_image (m->klass)))
                collect_signature_images (mono_method_signature_internal (m), data);
}

static void
collect_aggregate_modifiers_images (MonoAggregateModContainer *amods, CollectData *data)
{
        for (int i = 0; i < amods->count; ++i)
                collect_type_images (amods->modifiers [i].type, data);
}
        
static void
collect_type_images (MonoType *type, CollectData *data)
{
retry:
        if (G_UNLIKELY (type->has_cmods && mono_type_is_aggregate_mods (type))) {
                collect_aggregate_modifiers_images (mono_type_get_amods (type), data);
        }

        switch (type->type) {
        case MONO_TYPE_GENERICINST:
                collect_gclass_images (type->data.generic_class, data);
                break;
        case MONO_TYPE_PTR:
                type = type->data.type;
                goto retry;
        case MONO_TYPE_SZARRAY:
                type = m_class_get_byval_arg (type->data.klass);
                goto retry;
        case MONO_TYPE_ARRAY:
                type = m_class_get_byval_arg (type->data.array->eklass);
                goto retry;
        case MONO_TYPE_FNPTR:
                collect_signature_images (type->data.method, data);
                break;
        case MONO_TYPE_VAR:
        case MONO_TYPE_MVAR:
        {
                MonoImage *image = mono_get_image_for_generic_param (type->data.generic_param);
                add_image (image, data);
                type = type->data.generic_param->gshared_constraint;
                if (type)
                        goto retry;
                break;
        }
        case MONO_TYPE_CLASS:
        case MONO_TYPE_VALUETYPE:
                add_image (m_class_get_image (mono_class_from_mono_type_internal (type)), data);
                break;
        default:
                add_image (mono_defaults.corlib, data);
        }
}

typedef struct {
        MonoImage *image;
        GSList *list;
} CleanForImageUserData;

static gboolean
steal_gclass_in_image (gpointer key, gpointer value, gpointer data)
{
        MonoGenericClass *gclass = (MonoGenericClass *)key;
        CleanForImageUserData *user_data = (CleanForImageUserData *)data;

        g_assert (gclass_in_image (gclass, user_data->image));

        user_data->list = g_slist_prepend (user_data->list, gclass);
        return TRUE;
}

static gboolean
steal_ginst_in_image (gpointer key, gpointer value, gpointer data)
{
        MonoGenericInst *ginst = (MonoGenericInst *)key;
        CleanForImageUserData *user_data = (CleanForImageUserData *)data;

        // This doesn't work during corlib compilation
        //g_assert (ginst_in_image (ginst, user_data->image));

        user_data->list = g_slist_prepend (user_data->list, ginst);
        return TRUE;
}

static gboolean
steal_aggregate_modifiers_in_image (gpointer key, gpointer value, gpointer data)
{
        MonoAggregateModContainer *amods = (MonoAggregateModContainer *)key;
        CleanForImageUserData *user_data = (CleanForImageUserData *)data;

        g_assert (aggregate_modifiers_in_image (amods, user_data->image));

        user_data->list = g_slist_prepend (user_data->list, amods);
        return TRUE;
}

static gboolean
inflated_method_in_image (gpointer key, gpointer value, gpointer data)
{
        MonoImage *image = (MonoImage *)data;
        MonoMethodInflated *method = (MonoMethodInflated *)key;

        // FIXME:
        // https://bugzilla.novell.com/show_bug.cgi?id=458168
        g_assert (m_class_get_image (method->declaring->klass) == image ||
                (method->context.class_inst && ginst_in_image (method->context.class_inst, image)) ||
                          (method->context.method_inst && ginst_in_image (method->context.method_inst, image)) || (((MonoMethod*)method)->signature && signature_in_image (mono_method_signature_internal ((MonoMethod*)method), image)));

        return TRUE;
}

static gboolean
inflated_signature_in_image (gpointer key, gpointer value, gpointer data)
{
        MonoImage *image = (MonoImage *)data;
        MonoInflatedMethodSignature *sig = (MonoInflatedMethodSignature *)key;

        return signature_in_image (sig->sig, image) ||
                (sig->context.class_inst && ginst_in_image (sig->context.class_inst, image)) ||
                (sig->context.method_inst && ginst_in_image (sig->context.method_inst, image));
}

static gboolean
class_in_image (gpointer key, gpointer value, gpointer data)
{
        MonoImage *image = (MonoImage *)data;
        MonoClass *klass = (MonoClass *)key;

        g_assert (type_in_image (m_class_get_byval_arg (klass), image));

        return TRUE;
}

static void
check_gmethod (gpointer key, gpointer value, gpointer data)
{
        MonoMethodInflated *method = (MonoMethodInflated *)key;
        MonoImage *image = (MonoImage *)data;

        if (method->context.class_inst)
                g_assert (!ginst_in_image (method->context.class_inst, image));
        if (method->context.method_inst)
                g_assert (!ginst_in_image (method->context.method_inst, image));
        if (((MonoMethod*)method)->signature)
                g_assert (!signature_in_image (mono_method_signature_internal ((MonoMethod*)method), image));
}

/*
 * check_image_sets:
 *
 *   Run a consistency check on the image set data structures.
 */
static G_GNUC_UNUSED void
check_image_sets (MonoImage *image)
{
        int i;
        GSList *l = image->image_sets;

        if (!image_sets)
                return;

        for (i = 0; i < image_sets->len; ++i) {
                MonoImageSet *set = (MonoImageSet *)g_ptr_array_index (image_sets, i);

                if (!g_slist_find (l, set)) {
                        g_hash_table_foreach (set->gmethod_cache, check_gmethod, image);
                }
        }
}

void
mono_metadata_clean_for_image (MonoImage *image)
{
        CleanForImageUserData ginst_data, gclass_data, amods_data;
        GSList *l, *set_list;

        //check_image_sets (image);

        /*
         * The data structures could reference each other so we delete them in two phases.
         * This is required because of the hashing functions in gclass/ginst_cache.
         */
        ginst_data.image = gclass_data.image = image;
        ginst_data.list = gclass_data.list = NULL;
        amods_data.image = image;
        amods_data.list = NULL;

        /* Collect the items to delete */
        /* delete_image_set () modifies the lists so make a copy */
        for (l = image->image_sets; l; l = l->next) {
                MonoImageSet *set = (MonoImageSet *)l->data;

                mono_image_set_lock (set);
                mono_conc_hashtable_foreach_steal (set->gclass_cache, steal_gclass_in_image, &gclass_data);
                g_hash_table_foreach_steal (set->ginst_cache, steal_ginst_in_image, &ginst_data);
                g_hash_table_foreach_remove (set->gmethod_cache, inflated_method_in_image, image);
                g_hash_table_foreach_remove (set->gsignature_cache, inflated_signature_in_image, image);

                g_hash_table_foreach_steal (set->szarray_cache, class_in_image, image);
                g_hash_table_foreach_steal (set->array_cache, class_in_image, image);
                if (set->ptr_cache)
                        g_hash_table_foreach_steal (set->ptr_cache, class_in_image, image);

                g_hash_table_foreach_steal (set->aggregate_modifiers_cache, steal_aggregate_modifiers_in_image, &amods_data);

                mono_image_set_unlock (set);
        }

        /* Delete the removed items */
        for (l = ginst_data.list; l; l = l->next)
                free_generic_inst ((MonoGenericInst *)l->data);
        for (l = gclass_data.list; l; l = l->next)
                free_generic_class ((MonoGenericClass *)l->data);
        for (l = amods_data.list; l; l = l->next)
                free_aggregate_modifiers ((MonoAggregateModContainer *)l->data);
        g_slist_free (ginst_data.list);
        g_slist_free (gclass_data.list);
        /* delete_image_set () modifies the lists so make a copy */
        set_list = g_slist_copy (image->image_sets);
        for (l = set_list; l; l = l->next) {
                MonoImageSet *set = (MonoImageSet *)l->data;

                delete_image_set (set);
        }
        g_slist_free (set_list);
}

static void
free_inflated_method (MonoMethodInflated *imethod)
{
        MonoMethod *method = (MonoMethod*)imethod;

        if (method->signature)
                mono_metadata_free_inflated_signature (method->signature);

        if (method->wrapper_type)
                g_free (((MonoMethodWrapper*)method)->method_data);

        g_free (method);
}

static void
free_generic_inst (MonoGenericInst *ginst)
{
        int i;

        /* The ginst itself is allocated from the image set mempool */
        for (i = 0; i < ginst->type_argc; ++i)
                mono_metadata_free_type (ginst->type_argv [i]);
}

static void
free_generic_class (MonoGenericClass *gclass)
{
        /* The gclass itself is allocated from the image set mempool */
        if (gclass->cached_class && m_class_get_interface_id (gclass->cached_class))
                mono_unload_interface_id (gclass->cached_class);
}

static void
free_inflated_signature (MonoInflatedMethodSignature *sig)
{
        mono_metadata_free_inflated_signature (sig->sig);
        g_free (sig);
}

static void
free_aggregate_modifiers (MonoAggregateModContainer *amods)
{
        for (int i = 0; i < amods->count; i++)
                mono_metadata_free_type (amods->modifiers [i].type);
        /* the container itself is allocated in the image set mempool */
}

/*
 * mono_metadata_get_inflated_signature:
 *
 *   Given an inflated signature and a generic context, return a canonical copy of the 
 * signature. The returned signature might be equal to SIG or it might be a cached copy.
 */
MonoMethodSignature *
mono_metadata_get_inflated_signature (MonoMethodSignature *sig, MonoGenericContext *context)
{
        MonoInflatedMethodSignature helper;
        MonoInflatedMethodSignature *res;
        CollectData data;
        MonoImageSet *set;

        helper.sig = sig;
        helper.context.class_inst = context->class_inst;
        helper.context.method_inst = context->method_inst;

        collect_data_init (&data);

        collect_inflated_signature_images (&helper, &data);

        set = get_image_set (data.images, data.nimages);

        collect_data_free (&data);

        mono_image_set_lock (set);

        res = (MonoInflatedMethodSignature *)g_hash_table_lookup (set->gsignature_cache, &helper);
        if (!res) {
                res = g_new0 (MonoInflatedMethodSignature, 1);
                res->sig = sig;
                res->context.class_inst = context->class_inst;
                res->context.method_inst = context->method_inst;
                g_hash_table_insert (set->gsignature_cache, res, res);
        }

        mono_image_set_unlock (set);

        return res->sig;
}

MonoImageSet *
mono_metadata_get_image_set_for_type (MonoType *type)
{
        MonoImageSet *set;
        CollectData image_set_data;

        collect_data_init (&image_set_data);
        collect_type_images (type, &image_set_data);
        set = get_image_set (image_set_data.images, image_set_data.nimages);
        collect_data_free (&image_set_data);

        return set;
}

MonoImageSet *
mono_metadata_get_image_set_for_class (MonoClass *klass)
{
        return mono_metadata_get_image_set_for_type (m_class_get_byval_arg (klass));
}

MonoImageSet *
mono_metadata_get_image_set_for_method (MonoMethodInflated *method)
{
        MonoImageSet *set;
        CollectData image_set_data;

        collect_data_init (&image_set_data);
        collect_method_images (method, &image_set_data);
        set = get_image_set (image_set_data.images, image_set_data.nimages);
        collect_data_free (&image_set_data);

        return set;
}

MonoImageSet *
mono_metadata_get_image_set_for_aggregate_modifiers (MonoAggregateModContainer *amods)
{
        MonoImageSet *set;
        CollectData image_set_data;
        collect_data_init (&image_set_data);
        collect_aggregate_modifiers_images (amods, &image_set_data);
        set = get_image_set (image_set_data.images, image_set_data.nimages);
        collect_data_free (&image_set_data);

        return set;
}

MonoImageSet *
mono_metadata_merge_image_sets (MonoImageSet *set1, MonoImageSet *set2)
{
        MonoImage **images = g_newa (MonoImage*, set1->nimages + set2->nimages);

        /* Add images from set1 */
        memcpy (images, set1->images, sizeof (MonoImage*) * set1->nimages);

        int nimages = set1->nimages;
        // FIXME: Quaratic
        /* Add images from set2 */
        for (int i = 0; i < set2->nimages; ++i) {
                int j;
                for (j = 0; j < set1->nimages; ++j) {
                        if (set2->images [i] == set1->images [j])
                                break;
                }
                if (j == set1->nimages)
                        images [nimages ++] = set2->images [i];
        }
        return get_image_set (images, nimages);
}

static gboolean
type_is_gtd (MonoType *type)
{
        switch (type->type) {
        case MONO_TYPE_CLASS:
        case MONO_TYPE_VALUETYPE:
                return mono_class_is_gtd (type->data.klass);
        default:
                return FALSE;
        }
}

/*
 * mono_metadata_get_generic_inst:
 *
 * Given a list of types, return a MonoGenericInst that represents that list.
 * The returned MonoGenericInst has its own copy of the list of types.  The list
 * passed in the argument can be freed, modified or disposed of.
 *
 */
MonoGenericInst *
mono_metadata_get_generic_inst (int type_argc, MonoType **type_argv)
{
        MonoGenericInst *ginst;
        gboolean is_open;
        int i;
        int size = MONO_SIZEOF_GENERIC_INST + type_argc * sizeof (MonoType *);

        for (i = 0; i < type_argc; ++i)
                if (mono_class_is_open_constructed_type (type_argv [i]))
                        break;
        is_open = (i < type_argc);

        ginst = (MonoGenericInst *)g_alloca (size);
        memset (ginst, 0, sizeof (MonoGenericInst));
        ginst->is_open = is_open;
        ginst->type_argc = type_argc;
        memcpy (ginst->type_argv, type_argv, type_argc * sizeof (MonoType *));

        for (i = 0; i < type_argc; ++i) {
                MonoType *t = ginst->type_argv [i];
                if (type_is_gtd (t)) {
                        ginst->type_argv [i] = mono_class_gtd_get_canonical_inst (t->data.klass);
                }
        }

        return mono_metadata_get_canonical_generic_inst (ginst);
}

/**
 * mono_metadata_get_canonical_generic_inst:
 * \param candidate an arbitrary generic instantiation
 *
 * \returns the canonical generic instantiation that represents the given
 * candidate by identifying the image set for the candidate instantiation and
 * finding the instance in the image set or adding a copy of the given instance
 * to the image set.
 *
 * The returned MonoGenericInst has its own copy of the list of types.  The list
 * passed in the argument can be freed, modified or disposed of.
 *
 */
MonoGenericInst *
mono_metadata_get_canonical_generic_inst (MonoGenericInst *candidate)
{
        CollectData data;
        int type_argc = candidate->type_argc;
        gboolean is_open = candidate->is_open;
        MonoImageSet *set;

        collect_data_init (&data);

        collect_ginst_images (candidate, &data);

        set = get_image_set (data.images, data.nimages);

        collect_data_free (&data);

        mono_image_set_lock (set);

        MonoGenericInst *ginst = (MonoGenericInst *)g_hash_table_lookup (set->ginst_cache, candidate);
        if (!ginst) {
                int size = MONO_SIZEOF_GENERIC_INST + type_argc * sizeof (MonoType *);
                ginst = (MonoGenericInst *)mono_image_set_alloc0 (set, size);
#ifndef MONO_SMALL_CONFIG
                ginst->id = mono_atomic_inc_i32 (&next_generic_inst_id);
#endif
                ginst->is_open = is_open;
                ginst->type_argc = type_argc;

                for (int i = 0; i < type_argc; ++i)
                        ginst->type_argv [i] = mono_metadata_type_dup (NULL, candidate->type_argv [i]);

                g_hash_table_insert (set->ginst_cache, ginst, ginst);
        }

        mono_image_set_unlock (set);
        return ginst;
}

MonoAggregateModContainer *
mono_metadata_get_canonical_aggregate_modifiers (MonoAggregateModContainer *candidate)
{
        g_assert (candidate->count > 0);
        MonoImageSet *set = mono_metadata_get_image_set_for_aggregate_modifiers (candidate);
        
        mono_image_set_lock (set);

        MonoAggregateModContainer *amods = (MonoAggregateModContainer *)g_hash_table_lookup (set->aggregate_modifiers_cache, candidate);
        if (!amods) {
                size_t size = mono_sizeof_aggregate_modifiers (candidate->count);
                amods = (MonoAggregateModContainer *)mono_image_set_alloc0 (set, size);
                amods->count = candidate->count;
                for (int i = 0; i < candidate->count; ++i) {
                        amods->modifiers [i].required = candidate->modifiers [i].required;
                        amods->modifiers [i].type = mono_metadata_type_dup (NULL, candidate->modifiers [i].type);
                }

                g_hash_table_insert (set->aggregate_modifiers_cache, amods, amods);
        }
        mono_image_set_unlock (set);
        return amods;
}

static gboolean
mono_metadata_is_type_builder_generic_type_definition (MonoClass *container_class, MonoGenericInst *inst, gboolean is_dynamic)
{
        MonoGenericContainer *container = mono_class_get_generic_container (container_class); 

        if (!is_dynamic || m_class_was_typebuilder (container_class) || container->type_argc != inst->type_argc)
                return FALSE;
        return inst == container->context.class_inst;
}

/*
 * mono_metadata_lookup_generic_class:
 *
 * Returns a MonoGenericClass with the given properties.
 *
 */
MonoGenericClass *
mono_metadata_lookup_generic_class (MonoClass *container_class, MonoGenericInst *inst, gboolean is_dynamic)
{
        MonoGenericClass *gclass;
        MonoGenericClass helper;
        gboolean is_tb_open = mono_metadata_is_type_builder_generic_type_definition (container_class, inst, is_dynamic);
        MonoImageSet *set;
        CollectData data;

        g_assert (mono_class_get_generic_container (container_class)->type_argc == inst->type_argc);

        memset (&helper, 0, sizeof(helper)); // act like g_new0
        helper.container_class = container_class;
        helper.context.class_inst = inst;
        helper.is_dynamic = is_dynamic; /* We use this in a hash lookup, which does not attempt to downcast the pointer */
        helper.is_tb_open = is_tb_open;

        collect_data_init (&data);

        collect_gclass_images (&helper, &data);

        set = get_image_set (data.images, data.nimages);

        collect_data_free (&data);

        gclass = (MonoGenericClass *)mono_conc_hashtable_lookup (set->gclass_cache, &helper);

        /* A tripwire just to keep us honest */
        g_assert (!helper.cached_class);

        if (gclass)
                return gclass;

        gclass = mono_image_set_new0 (set, MonoGenericClass, 1);
        if (is_dynamic)
                gclass->is_dynamic = 1;

        gclass->is_tb_open = is_tb_open;
        gclass->container_class = container_class;
        gclass->context.class_inst = inst;
        gclass->context.method_inst = NULL;
        gclass->owner = set;
        if (inst == mono_class_get_generic_container (container_class)->context.class_inst && !is_tb_open)
                gclass->cached_class = container_class;

        mono_image_set_lock (set);

        MonoGenericClass *gclass2 = (MonoGenericClass*)mono_conc_hashtable_insert (set->gclass_cache, gclass, gclass);
        if (!gclass2)
                gclass2 = gclass;

        // g_hash_table_insert (set->gclass_cache, gclass, gclass);

        mono_image_set_unlock (set);

        return gclass2;
}

/*
 * mono_metadata_inflate_generic_inst:
 *
 * Instantiate the generic instance @ginst with the context @context.
 * Check @error for success.
 *
 */
MonoGenericInst *
mono_metadata_inflate_generic_inst (MonoGenericInst *ginst, MonoGenericContext *context, MonoError *error)
{
        MonoType **type_argv;
        MonoGenericInst *nginst = NULL;
        int i, count = 0;

        error_init (error);

        if (!ginst->is_open)
                return ginst;

        type_argv = g_new0 (MonoType*, ginst->type_argc);

        for (i = 0; i < ginst->type_argc; i++) {
                type_argv [i] = mono_class_inflate_generic_type_checked (ginst->type_argv [i], context, error);
                if (!is_ok (error))
                        goto cleanup;
                ++count;
        }

        nginst = mono_metadata_get_generic_inst (ginst->type_argc, type_argv);

cleanup:
        for (i = 0; i < count; i++)
                mono_metadata_free_type (type_argv [i]);
        g_free (type_argv);

        return nginst;
}

MonoGenericInst *
mono_metadata_parse_generic_inst (MonoImage *m, MonoGenericContainer *container,
                                  int count, const char *ptr, const char **rptr, MonoError *error)
{
        MonoType **type_argv;
        MonoGenericInst *ginst = NULL;
        int i, parse_count = 0;

        error_init (error);
        type_argv = g_new0 (MonoType*, count);

        for (i = 0; i < count; i++) {
                /* this can be a transient type, mono_metadata_get_generic_inst will allocate
                 * a canonical one, if needed.
                 */
                MonoType *t = mono_metadata_parse_type_checked (m, container, 0, TRUE, ptr, &ptr, error);
                if (!t)
                        goto cleanup;
                type_argv [i] = t;
                parse_count++;
        }

        if (rptr)
                *rptr = ptr;

        g_assert (parse_count == count);
        ginst = mono_metadata_get_generic_inst (count, type_argv);

cleanup:
        for (i = 0; i < parse_count; i++)
                mono_metadata_free_type (type_argv [i]);
        g_free (type_argv);

        return ginst;
}

static gboolean
do_mono_metadata_parse_generic_class (MonoType *type, MonoImage *m, MonoGenericContainer *container,
                                      const char *ptr, const char **rptr, MonoError *error)
{
        MonoGenericInst *inst;
        MonoClass *gklass;
        MonoType *gtype;
        int count;

        error_init (error);

        // XXX how about transient?
        gtype = mono_metadata_parse_type_checked (m, NULL, 0, FALSE, ptr, &ptr, error);
        if (gtype == NULL)
                return FALSE;

        gklass = mono_class_from_mono_type_internal (gtype);
        if (!mono_class_is_gtd (gklass)) {
                mono_error_set_bad_image (error, m, "Generic instance with non-generic definition");
                return FALSE;
        }

        count = mono_metadata_decode_value (ptr, &ptr);
        inst = mono_metadata_parse_generic_inst (m, container, count, ptr, &ptr, error);
        if (inst == NULL)
                return FALSE;

        if (rptr)
                *rptr = ptr;

        type->data.generic_class = mono_metadata_lookup_generic_class (gklass, inst, FALSE);
        return TRUE;
}

/*
 * select_container:
 * @gc: The generic container to normalize
 * @type: The kind of generic parameters the resulting generic-container should contain
 */

static MonoGenericContainer *
select_container (MonoGenericContainer *gc, MonoTypeEnum type)
{
        gboolean is_var = (type == MONO_TYPE_VAR);
        if (!gc)
                return NULL;

        g_assert (is_var || type == MONO_TYPE_MVAR);

        if (is_var) {
                if (gc->is_method || gc->parent)
                        /*
                         * The current MonoGenericContainer is a generic method -> its `parent'
                         * points to the containing class'es container.
                         */
                        return gc->parent;
        }

        return gc;
}

MonoGenericContainer *
mono_get_anonymous_container_for_image (MonoImage *image, gboolean is_mvar)
{
        MonoGenericContainer **container_pointer;
        if (is_mvar)
                container_pointer = &image->anonymous_generic_method_container;
        else
                container_pointer = &image->anonymous_generic_class_container;
        MonoGenericContainer *result = *container_pointer;

        // This container has never been created; make it now.
        if (!result)
        {
                // Note this is never deallocated anywhere-- it exists for the lifetime of the image it's allocated from
                result = (MonoGenericContainer *)mono_image_alloc0 (image, sizeof (MonoGenericContainer));
                result->owner.image = image;
                result->is_anonymous = TRUE;
                result->is_method = is_mvar;

                // If another thread already made a container, use that and leak this new one.
                // (Technically it would currently be safe to just assign instead of CASing.)
                MonoGenericContainer *exchange = (MonoGenericContainer *)mono_atomic_cas_ptr ((volatile gpointer *)container_pointer, result, NULL);
                if (exchange)
                        result = exchange;
        }
        return result;
}

#define FAST_GPARAM_CACHE_SIZE 16

static MonoGenericParam*
lookup_anon_gparam (MonoImage *image, MonoGenericContainer *container, gint32 param_num, gboolean is_mvar)
{
        if (param_num >= 0 && param_num < FAST_GPARAM_CACHE_SIZE) {
                MonoGenericParam *cache = is_mvar ? image->mvar_gparam_cache_fast : image->var_gparam_cache_fast;
                if (!cache)
                        return NULL;
                return &cache[param_num];
        } else {
                MonoGenericParam key;
                memset (&key, 0, sizeof (key));
                key.owner = container;
                key.num = param_num;
                key.gshared_constraint = NULL;
                MonoConcurrentHashTable *cache = is_mvar ? image->mvar_gparam_cache : image->var_gparam_cache;
                if (!cache)
                        return NULL;
                return (MonoGenericParam*)mono_conc_hashtable_lookup (cache, &key);
        }
}

static MonoGenericParam*
publish_anon_gparam_fast (MonoImage *image, MonoGenericContainer *container, gint32 param_num)
{
        g_assert (param_num >= 0 && param_num < FAST_GPARAM_CACHE_SIZE);
        MonoGenericParam **cache = container->is_method ? &image->mvar_gparam_cache_fast : &image->var_gparam_cache_fast;
        if (!*cache) {
                mono_image_lock (image);
                if (!*cache) {
                        *cache = (MonoGenericParam*)mono_image_alloc0 (image, sizeof (MonoGenericParam) * FAST_GPARAM_CACHE_SIZE);
                        for (gint32 i = 0; i < FAST_GPARAM_CACHE_SIZE; ++i) {
                                MonoGenericParam *param = &(*cache)[i];
                                param->owner = container;
                                param->num = i;
                        }
                }
                mono_image_unlock (image);
        }
        return &(*cache)[param_num];
}

/*
 * publish_anon_gparam_slow:
 *
 * Publish \p gparam anonymous generic parameter to the anon gparam cache for \p image.
 *
 * LOCKING: takes the image lock.
 */
static MonoGenericParam*
publish_anon_gparam_slow (MonoImage *image, MonoGenericParam *gparam)
{
        MonoConcurrentHashTable **cache = gparam->owner->is_method ? &image->mvar_gparam_cache : &image->var_gparam_cache;
        if (!*cache) {
                mono_image_lock (image);
                if (!*cache) {
                        MonoConcurrentHashTable *ht = mono_conc_hashtable_new ((GHashFunc)mono_metadata_generic_param_hash,
                                                                                (GEqualFunc) mono_metadata_generic_param_equal);
                        mono_atomic_store_release (cache, ht);
                }
                mono_image_unlock (image);
        }
        MonoGenericParam *other = (MonoGenericParam*)mono_conc_hashtable_insert (*cache, gparam, gparam);
        // If another thread published first return their param, otherwise return ours.
        return other ? other : gparam;
}

/**
 * mono_metadata_create_anon_gparam:
 * \param image the MonoImage that owns the anonymous generic parameter
 * \param param_num the parameter number
 * \param is_mvar TRUE if this is a method generic parameter, FALSE if it's a class generic parameter.
 *
 * Returns: a new, or exisisting \c MonoGenericParam for an anonymous generic parameter with the given properties.
 *
 * LOCKING: takes the image lock.
 */
MonoGenericParam*
mono_metadata_create_anon_gparam (MonoImage *image, gint32 param_num, gboolean is_mvar)
{
        MonoGenericContainer *container = mono_get_anonymous_container_for_image (image, is_mvar);
        MonoGenericParam *gparam = lookup_anon_gparam (image, container, param_num, is_mvar);
        if (gparam)
                return gparam;
        if (param_num >= 0 && param_num < FAST_GPARAM_CACHE_SIZE) {
                return publish_anon_gparam_fast (image, container, param_num);
        } else {
                // Create a candidate generic param and try to insert it in the cache.
                // If multiple threads both try to publish the same param, all but one
                // will leak, but that's okay.
                gparam = (MonoGenericParam*)mono_image_alloc0 (image, sizeof (MonoGenericParam));
                gparam->owner = container;
                gparam->num = param_num;

                return publish_anon_gparam_slow (image, gparam);
        }
}

/*
 * mono_metadata_parse_generic_param:
 * @generic_container: Our MonoClass's or MonoMethod's MonoGenericContainer;
 *                     see mono_metadata_parse_type_checked() for details.
 * Internal routine to parse a generic type parameter.
 * LOCKING: Acquires the loader lock
 */
static MonoGenericParam *
mono_metadata_parse_generic_param (MonoImage *m, MonoGenericContainer *generic_container,
                                   MonoTypeEnum type, const char *ptr, const char **rptr, MonoError *error)
{
        int index = mono_metadata_decode_value (ptr, &ptr);
        if (rptr)
                *rptr = ptr;

        error_init (error);

        generic_container = select_container (generic_container, type);
        if (!generic_container) {
                gboolean is_mvar = FALSE;
                switch (type)
                {
                        case MONO_TYPE_VAR:
                                break;
                        case MONO_TYPE_MVAR:
                                is_mvar = TRUE;
                                break;
                        default:
                                g_error ("Cerating generic param object with invalid MonoType"); // This is not a generic param
                }

                return mono_metadata_create_anon_gparam (m, index, is_mvar);
        }

        if (index >= generic_container->type_argc) {
                mono_error_set_bad_image (error, m, "Invalid generic %s parameter index %d, max index is %d",
                        generic_container->is_method ? "method" : "type",
                        index, generic_container->type_argc);
                return NULL;
        }

        //This can't return NULL
        return mono_generic_container_get_param (generic_container, index);
}

/*
 * mono_metadata_get_shared_type:
 *
 *   Return a shared instance of TYPE, if available, NULL otherwise.
 * Shared MonoType instances help save memory. Their contents should not be modified
 * by the caller. They do not need to be freed as their lifetime is bound by either
 * the lifetime of the runtime (builtin types), or the lifetime of the MonoClass
 * instance they are embedded in. If they are freed, they should be freed using
 * mono_metadata_free_type () instead of g_free ().
 */
MonoType*
mono_metadata_get_shared_type (MonoType *type)
{
        MonoType *cached;

        /* No need to use locking since nobody is modifying the hash table */
        if ((cached = (MonoType *)g_hash_table_lookup (type_cache, type)))
                return cached;

        switch (type->type){
        case MONO_TYPE_CLASS:
        case MONO_TYPE_VALUETYPE:
                if (type == m_class_get_byval_arg (type->data.klass))
                        return type;
                if (type == m_class_get_this_arg (type->data.klass))
                        return type;
                break;
        default:
                break;
        }

        return NULL;
}

static gboolean
compare_type_literals (MonoImage *image, int class_type, int type_type, MonoError *error)
{
        error_init (error);

        /* _byval_arg.type can be zero if we're decoding a type that references a class been loading.
         * See mcs/test/gtest-440. and #650936.
         * FIXME This better be moved to the metadata verifier as it can catch more cases.
         */
        if (!class_type)
                return TRUE;
        /* NET 1.1 assemblies might encode string and object in a denormalized way.
         * See #675464.
         */
        if (class_type == type_type)
                return TRUE;

        if (type_type == MONO_TYPE_CLASS) {
                if (class_type == MONO_TYPE_STRING || class_type == MONO_TYPE_OBJECT)
                        return TRUE;
                //XXX stringify this argument
                mono_error_set_bad_image (error, image, "Expected reference type but got type kind %d", class_type);
                return FALSE;
        }

        g_assert (type_type == MONO_TYPE_VALUETYPE);
        switch (class_type) {
        case MONO_TYPE_BOOLEAN:
        case MONO_TYPE_CHAR:
        case MONO_TYPE_I1:
        case MONO_TYPE_U1:
        case MONO_TYPE_I2:
        case MONO_TYPE_U2:
        case MONO_TYPE_I4:
        case MONO_TYPE_U4:
        case MONO_TYPE_I8:
        case MONO_TYPE_U8:
        case MONO_TYPE_R4:
        case MONO_TYPE_R8:
        case MONO_TYPE_I:
        case MONO_TYPE_U:
        case MONO_TYPE_CLASS:
                return TRUE;
        default:
                //XXX stringify this argument
                mono_error_set_bad_image (error, image, "Expected value type but got type kind %d", class_type);
                return FALSE;
        }
}

static gboolean
verify_var_type_and_container (MonoImage *image, int var_type, MonoGenericContainer *container, MonoError *error)
{
        error_init (error);
        if (var_type == MONO_TYPE_MVAR) {
                if (!container->is_method) { //MVAR and a method container
                        mono_error_set_bad_image (error, image, "MVAR parsed in a context without a method container");
                        return FALSE;
                }
        } else {
                if (!(!container->is_method || //VAR and class container
                        (container->is_method && container->parent))) { //VAR and method container with parent
                        mono_error_set_bad_image (error, image, "VAR parsed in a context without a class container");
                        return FALSE;
                }
        }
        return TRUE;
}

/* 
 * do_mono_metadata_parse_type:
 * @type: MonoType to be filled in with the return value
 * @m: image context
 * @generic_context: generics_context
 * @transient: whenever to allocate data from the heap
 * @ptr: pointer to the encoded type
 * @rptr: pointer where the end of the encoded type is saved
 * 
 * Internal routine used to "fill" the contents of @type from an 
 * allocated pointer.  This is done this way to avoid doing too
 * many mini-allocations (particularly for the MonoFieldType which
 * most of the time is just a MonoType, but sometimes might be augmented).
 *
 * This routine is used by mono_metadata_parse_type and
 * mono_metadata_parse_field_type
 *
 * This extracts a Type as specified in Partition II (22.2.12) 
 *
 * Returns: FALSE if the type could not be loaded
 */
static gboolean
do_mono_metadata_parse_type (MonoType *type, MonoImage *m, MonoGenericContainer *container,
                                                         gboolean transient, const char *ptr, const char **rptr, MonoError *error)
{
        error_init (error);

        type->type = (MonoTypeEnum)mono_metadata_decode_value (ptr, &ptr);
        
        switch (type->type){
        case MONO_TYPE_VOID:
        case MONO_TYPE_BOOLEAN:
        case MONO_TYPE_CHAR:
        case MONO_TYPE_I1:
        case MONO_TYPE_U1:
        case MONO_TYPE_I2:
        case MONO_TYPE_U2:
        case MONO_TYPE_I4:
        case MONO_TYPE_U4:
        case MONO_TYPE_I8:
        case MONO_TYPE_U8:
        case MONO_TYPE_R4:
        case MONO_TYPE_R8:
        case MONO_TYPE_I:
        case MONO_TYPE_U:
        case MONO_TYPE_STRING:
        case MONO_TYPE_OBJECT:
        case MONO_TYPE_TYPEDBYREF:
                break;
        case MONO_TYPE_VALUETYPE:
        case MONO_TYPE_CLASS: {
                guint32 token;
                MonoClass *klass;
                token = mono_metadata_parse_typedef_or_ref (m, ptr, &ptr);
                klass = mono_class_get_checked (m, token, error);
                type->data.klass = klass;
                if (!klass)
                        return FALSE;

                if (!compare_type_literals (m, m_class_get_byval_arg (klass)->type, type->type, error))
                        return FALSE;

                break;
        }
        case MONO_TYPE_SZARRAY: {
                MonoType *etype = mono_metadata_parse_type_checked (m, container, 0, transient, ptr, &ptr, error);
                if (!etype)
                        return FALSE;

                type->data.klass = mono_class_from_mono_type_internal (etype);

                if (transient)
                        mono_metadata_free_type (etype);

                g_assert (type->data.klass); //This was previously a check for NULL, but mcfmt should never fail. It can return a borken MonoClass, but should return at least something.
                break;
        }
        case MONO_TYPE_PTR: {
                type->data.type = mono_metadata_parse_type_checked (m, container, 0, transient, ptr, &ptr, error);
                if (!type->data.type)
                        return FALSE;
                break;
        }
        case MONO_TYPE_FNPTR: {
                type->data.method = mono_metadata_parse_method_signature_full (m, container, 0, ptr, &ptr, error);
                if (!type->data.method)
                        return FALSE;
                break;
        }
        case MONO_TYPE_ARRAY: {
                type->data.array = mono_metadata_parse_array_internal (m, container, transient, ptr, &ptr, error);
                if (!type->data.array)
                        return FALSE;
                break;
        }
        case MONO_TYPE_MVAR:
        case MONO_TYPE_VAR: {
                if (container && !verify_var_type_and_container (m, type->type, container, error))
                        return FALSE;

                type->data.generic_param = mono_metadata_parse_generic_param (m, container, type->type, ptr, &ptr, error);
                if (!type->data.generic_param)
                        return FALSE;

                break;
        }
        case MONO_TYPE_GENERICINST: {
                if (!do_mono_metadata_parse_generic_class (type, m, container, ptr, &ptr, error))
                        return FALSE;
                break;
        }
        default:
                mono_error_set_bad_image (error, m, "type 0x%02x not handled in do_mono_metadata_parse_type on image %s", type->type, m->name);
                return FALSE;
        }
        
        if (rptr)
                *rptr = ptr;
        return TRUE;
}

/**
 * mono_metadata_free_type:
 * \param type type to free
 *
 * Free the memory allocated for type \p type which is allocated on the heap.
 */
void
mono_metadata_free_type (MonoType *type)
{
        if (type >= builtin_types && type < builtin_types + NBUILTIN_TYPES ())
                return;
        
        switch (type->type){
        case MONO_TYPE_OBJECT:
        case MONO_TYPE_STRING:
                if (!type->data.klass)
                        break;
                /* fall through */
        case MONO_TYPE_CLASS:
        case MONO_TYPE_VALUETYPE:
                if (type == m_class_get_byval_arg (type->data.klass) || type == m_class_get_this_arg (type->data.klass))
                        return;
                break;
        case MONO_TYPE_PTR:
                mono_metadata_free_type (type->data.type);
                break;
        case MONO_TYPE_FNPTR:
                mono_metadata_free_method_signature (type->data.method);
                break;
        case MONO_TYPE_ARRAY:
                mono_metadata_free_array (type->data.array);
                break;
        default:
                break;
        }

        g_free (type);
}

#if 0
static void
hex_dump (const char *buffer, int base, int count)
{
        int show_header = 1;
        int i;

        if (count < 0){
                count = -count;
                show_header = 0;
        }
        
        for (i = 0; i < count; i++){
                if (show_header)
                        if ((i % 16) == 0)
                                printf ("\n0x%08x: ", (unsigned char) base + i);

                printf ("%02x ", (unsigned char) (buffer [i]));
        }
        fflush (stdout);
}
#endif

/** 
 * @ptr: Points to the beginning of the Section Data (25.3)
 */
static MonoExceptionClause*
parse_section_data (MonoImage *m, int *num_clauses, const unsigned char *ptr, MonoError *error)
{
        unsigned char sect_data_flags;
        int is_fat;
        guint32 sect_data_len;
        MonoExceptionClause* clauses = NULL;

        error_init (error);
        
        while (1) {
                /* align on 32-bit boundary */
                ptr = dword_align (ptr); 
                sect_data_flags = *ptr;
                ptr++;
                
                is_fat = sect_data_flags & METHOD_HEADER_SECTION_FAT_FORMAT;
                if (is_fat) {
                        sect_data_len = (ptr [2] << 16) | (ptr [1] << 8) | ptr [0];
                        ptr += 3;
                } else {
                        sect_data_len = ptr [0];
                        ++ptr;
                }

                if (sect_data_flags & METHOD_HEADER_SECTION_EHTABLE) {
                        const unsigned char *p = dword_align (ptr);
                        int i;
                        *num_clauses = is_fat ? sect_data_len / 24: sect_data_len / 12;
                        /* we could just store a pointer if we don't need to byteswap */
                        clauses = (MonoExceptionClause *)g_malloc0 (sizeof (MonoExceptionClause) * (*num_clauses));
                        for (i = 0; i < *num_clauses; ++i) {
                                MonoExceptionClause *ec = &clauses [i];
                                guint32 tof_value;
                                if (is_fat) {
                                        ec->flags = read32 (p);
                                        ec->try_offset = read32 (p + 4);
                                        ec->try_len = read32 (p + 8);
                                        ec->handler_offset = read32 (p + 12);
                                        ec->handler_len = read32 (p + 16);
                                        tof_value = read32 (p + 20);
                                        p += 24;
                                } else {
                                        ec->flags = read16 (p);
                                        ec->try_offset = read16 (p + 2);
                                        ec->try_len = *(p + 4);
                                        ec->handler_offset = read16 (p + 5);
                                        ec->handler_len = *(p + 7);
                                        tof_value = read32 (p + 8);
                                        p += 12;
                                }
                                if (ec->flags == MONO_EXCEPTION_CLAUSE_FILTER) {
                                        ec->data.filter_offset = tof_value;
                                } else if (ec->flags == MONO_EXCEPTION_CLAUSE_NONE) {
                                        ec->data.catch_class = NULL;
                                        if (tof_value) {
                                                ec->data.catch_class = mono_class_get_checked (m, tof_value, error);
                                                if (!is_ok (error)) {
                                                        g_free (clauses);
                                                        return NULL;
                                                }
                                        }
                                } else {
                                        ec->data.catch_class = NULL;
                                }
                                /* g_print ("try %d: %x %04x-%04x %04x\n", i, ec->flags, ec->try_offset, ec->try_offset+ec->try_len, ec->try_len); */
                        }

                }
                if (sect_data_flags & METHOD_HEADER_SECTION_MORE_SECTS)
                        ptr += sect_data_len - 4; /* LAMESPEC: it seems the size includes the header */
                else
                        return clauses;
        }
}

/*
 * mono_method_get_header_summary:
 * @method: The method to get the header.
 * @summary: Where to store the header
 *
 *
 * Returns: TRUE if the header was properly decoded.
 */
gboolean
mono_method_get_header_summary (MonoMethod *method, MonoMethodHeaderSummary *summary)
{
        int idx;
        guint32 rva;
        MonoImage* img;
        const char *ptr;
        unsigned char flags, format;
        guint16 fat_flags;
        ERROR_DECL (error);

        /*Only the GMD has a pointer to the metadata.*/
        while (method->is_inflated)
                method = ((MonoMethodInflated*)method)->declaring;

        summary->code = NULL;
        summary->code_size = 0;
        summary->max_stack = 0;
        summary->has_clauses = FALSE;
        summary->has_locals = FALSE;

        /*FIXME extract this into a MACRO and share it with mono_method_get_header*/
        if ((method->flags & METHOD_ATTRIBUTE_ABSTRACT) || (method->iflags & METHOD_IMPL_ATTRIBUTE_RUNTIME) || (method->iflags & METHOD_IMPL_ATTRIBUTE_INTERNAL_CALL) || (method->flags & METHOD_ATTRIBUTE_PINVOKE_IMPL))
                return FALSE;

        if (method->wrapper_type != MONO_WRAPPER_NONE || method->sre_method) {
                MonoMethodHeader *header =  ((MonoMethodWrapper *)method)->header;
                if (!header)
                        return FALSE;
                summary->code = header->code;
                summary->code_size = header->code_size;
                summary->max_stack = header->max_stack;
                summary->has_clauses = header->num_clauses > 0;
                summary->has_locals = header->num_locals > 0;
                return TRUE;
        }


        idx = mono_metadata_token_index (method->token);
        img = m_class_get_image (method->klass);
        rva = mono_metadata_decode_row_col (&img->tables [MONO_TABLE_METHOD], idx - 1, MONO_METHOD_RVA);

        /*We must run the verifier since we'll be decoding it.*/
        if (!mono_verifier_verify_method_header (img, rva, error)) {
                mono_error_cleanup (error);
                return FALSE;
        }

        ptr = mono_image_rva_map (img, rva);
        if (!ptr)
                return FALSE;

        flags = *(const unsigned char *)ptr;
        format = flags & METHOD_HEADER_FORMAT_MASK;

        switch (format) {
        case METHOD_HEADER_TINY_FORMAT:
                ptr++;
                summary->max_stack = 8;
                summary->code = (unsigned char *) ptr;
                summary->code_size = flags >> 2;
                break;
        case METHOD_HEADER_FAT_FORMAT:
                fat_flags = read16 (ptr);
                ptr += 2;
                summary->max_stack = read16 (ptr);
                ptr += 2;
                summary->code_size = read32 (ptr);
                ptr += 4;
                summary->has_locals = !!read32 (ptr);
                ptr += 4;
                if (fat_flags & METHOD_HEADER_MORE_SECTS)
                        summary->has_clauses = TRUE;
                summary->code = (unsigned char *) ptr;
                break;
        default:
                return FALSE;
        }
        return TRUE;
}

/*
 * mono_metadata_parse_mh_full:
 * @m: metadata context
 * @generic_context: generics context
 * @ptr: pointer to the method header.
 *
 * Decode the method header at @ptr, including pointer to the IL code,
 * info about local variables and optional exception tables.
 * This is a Mono runtime internal function.
 *
 * LOCKING: Acquires the loader lock.
 *
 * Returns: a transient MonoMethodHeader allocated from the heap.
 */
MonoMethodHeader *
mono_metadata_parse_mh_full (MonoImage *m, MonoGenericContainer *container, const char *ptr, MonoError *error)
{
        MonoMethodHeader *mh = NULL;
        unsigned char flags = *(const unsigned char *) ptr;
        unsigned char format = flags & METHOD_HEADER_FORMAT_MASK;
        guint16 fat_flags;
        guint32 local_var_sig_tok, max_stack, code_size, init_locals;
        const unsigned char *code;
        MonoExceptionClause* clauses = NULL;
        int num_clauses = 0;
        MonoTableInfo *t = &m->tables [MONO_TABLE_STANDALONESIG];
        guint32 cols [MONO_STAND_ALONE_SIGNATURE_SIZE];

        error_init (error);

        if (!ptr) {
                mono_error_set_bad_image (error, m, "Method header with null pointer");
                return NULL;
        }

        switch (format) {
        case METHOD_HEADER_TINY_FORMAT:
                mh = (MonoMethodHeader *)g_malloc0 (MONO_SIZEOF_METHOD_HEADER);
                ptr++;
                mh->max_stack = 8;
                mh->is_transient = TRUE;
                local_var_sig_tok = 0;
                mh->code_size = flags >> 2;
                mh->code = (unsigned char*)ptr;
                return mh;
        case METHOD_HEADER_FAT_FORMAT:
                fat_flags = read16 (ptr);
                ptr += 2;
                max_stack = read16 (ptr);
                ptr += 2;
                code_size = read32 (ptr);
                ptr += 4;
                local_var_sig_tok = read32 (ptr);
                ptr += 4;

                if (fat_flags & METHOD_HEADER_INIT_LOCALS)
                        init_locals = 1;
                else
                        init_locals = 0;

                code = (unsigned char*)ptr;

                if (!(fat_flags & METHOD_HEADER_MORE_SECTS))
                        break;

                /*
                 * There are more sections
                 */
                ptr = (char*)code + code_size;
                break;
        default:
                mono_error_set_bad_image (error, m, "Invalid method header format %d", format);
                return NULL;
        }

        if (local_var_sig_tok) {
                int idx = (local_var_sig_tok & 0xffffff)-1;
                if (idx >= t->rows || idx < 0) {
                        mono_error_set_bad_image (error, m, "Invalid method header local vars signature token 0x%8x", idx);
                        goto fail;
                }
                mono_metadata_decode_row (t, idx, cols, 1);

                if (!mono_verifier_verify_standalone_signature (m, cols [MONO_STAND_ALONE_SIGNATURE], error))
                        goto fail;
        }
        if (fat_flags & METHOD_HEADER_MORE_SECTS) {
                clauses = parse_section_data (m, &num_clauses, (const unsigned char*)ptr, error);
                goto_if_nok (error, fail);
        }
        if (local_var_sig_tok) {
                const char *locals_ptr;
                int len=0, i;

                locals_ptr = mono_metadata_blob_heap (m, cols [MONO_STAND_ALONE_SIGNATURE]);
                mono_metadata_decode_blob_size (locals_ptr, &locals_ptr);
                if (*locals_ptr != 0x07)
                        g_warning ("wrong signature for locals blob");
                locals_ptr++;
                len = mono_metadata_decode_value (locals_ptr, &locals_ptr);
                mh = (MonoMethodHeader *)g_malloc0 (MONO_SIZEOF_METHOD_HEADER + len * sizeof (MonoType*) + num_clauses * sizeof (MonoExceptionClause));
                mh->num_locals = len;
                for (i = 0; i < len; ++i) {
                        mh->locals [i] = mono_metadata_parse_type_internal (m, container, 0, TRUE, locals_ptr, &locals_ptr, error);
                        goto_if_nok (error, fail);
                }
        } else {
                mh = (MonoMethodHeader *)g_malloc0 (MONO_SIZEOF_METHOD_HEADER + num_clauses * sizeof (MonoExceptionClause));
        }
        mh->code = code;
        mh->code_size = code_size;
        mh->max_stack = max_stack;
        mh->is_transient = TRUE;
        mh->init_locals = init_locals;
        if (clauses) {
                MonoExceptionClause* clausesp = (MonoExceptionClause*)&mh->locals [mh->num_locals];
                memcpy (clausesp, clauses, num_clauses * sizeof (MonoExceptionClause));
                g_free (clauses);
                mh->clauses = clausesp;
                mh->num_clauses = num_clauses;
        }
        return mh;
fail:
        g_free (clauses);
        g_free (mh);
        return NULL;

}

/**
 * mono_metadata_parse_mh:
 * \param generic_context generics context
 * \param ptr pointer to the method header.
 *
 * Decode the method header at \p ptr, including pointer to the IL code,
 * info about local variables and optional exception tables.
 *
 * \returns a transient \c MonoMethodHeader allocated from the heap.
 */
MonoMethodHeader *
mono_metadata_parse_mh (MonoImage *m, const char *ptr)
{
        ERROR_DECL (error);
        MonoMethodHeader *header = mono_metadata_parse_mh_full (m, NULL, ptr, error);
        mono_error_cleanup (error);
        return header;
}

/**
 * mono_metadata_free_mh:
 * \param mh a method header
 *
 * Free the memory allocated for the method header.
 */
void
mono_metadata_free_mh (MonoMethodHeader *mh)
{
        int i;

        /* If it is not transient it means it's part of a wrapper method,
         * or a SRE-generated method, so the lifetime in that case is
         * dictated by the method's own lifetime
         */
        if (mh && mh->is_transient) {
                for (i = 0; i < mh->num_locals; ++i)
                        mono_metadata_free_type (mh->locals [i]);
                g_free (mh);
        }
}

/**
 * mono_method_header_get_code:
 * \param header a \c MonoMethodHeader pointer
 * \param code_size memory location for returning the code size
 * \param max_stack memory location for returning the max stack
 *
 * Method header accessor to retreive info about the IL code properties:
 * a pointer to the IL code itself, the size of the code and the max number
 * of stack slots used by the code.
 *
 * \returns pointer to the IL code represented by the method header.
 */
const unsigned char*
mono_method_header_get_code (MonoMethodHeader *header, guint32* code_size, guint32* max_stack)
{
        if (code_size)
                *code_size = header->code_size;
        if (max_stack)
                *max_stack = header->max_stack;
        return header->code;
}

/**
 * mono_method_header_get_locals:
 * \param header a \c MonoMethodHeader pointer
 * \param num_locals memory location for returning the number of local variables
 * \param init_locals memory location for returning the init_locals flag
 *
 * Method header accessor to retreive info about the local variables:
 * an array of local types, the number of locals and whether the locals
 * are supposed to be initialized to 0 on method entry
 *
 * \returns pointer to an array of types of the local variables
 */
MonoType**
mono_method_header_get_locals (MonoMethodHeader *header, guint32* num_locals, gboolean *init_locals)
{
        if (num_locals)
                *num_locals = header->num_locals;
        if (init_locals)
                *init_locals = header->init_locals;
        return header->locals;
}

/*
 * mono_method_header_get_num_clauses:
 * @header: a MonoMethodHeader pointer
 *
 * Method header accessor to retreive the number of exception clauses.
 *
 * Returns: the number of exception clauses present
 */
int
mono_method_header_get_num_clauses (MonoMethodHeader *header)
{
        return header->num_clauses;
}

/**
 * mono_method_header_get_clauses:
 * \param header a \c MonoMethodHeader pointer
 * \param method \c MonoMethod the header belongs to
 * \param iter pointer to a iterator
 * \param clause pointer to a \c MonoExceptionClause structure which will be filled with the info
 *
 * Get the info about the exception clauses in the method. Set \c *iter to NULL to
 * initiate the iteration, then call the method repeatedly until it returns FALSE.
 * At each iteration, the structure pointed to by clause if filled with the
 * exception clause information.
 *
 * \returns TRUE if clause was filled with info, FALSE if there are no more exception
 * clauses.
 */
int
mono_method_header_get_clauses (MonoMethodHeader *header, MonoMethod *method, gpointer *iter, MonoExceptionClause *clause)
{
        MonoExceptionClause *sc;
        /* later we'll be able to use this interface to parse the clause info on demand,
         * without allocating anything.
         */
        if (!iter || !header->num_clauses)
                return FALSE;
        if (!*iter) {
                *iter = sc = header->clauses;
                *clause = *sc;
                return TRUE;
        }
        sc = (MonoExceptionClause *)*iter;
        sc++;
        if (sc < header->clauses + header->num_clauses) {
                *iter = sc;
                *clause = *sc;
                return TRUE;
        }
        return FALSE;
}

/**
 * mono_metadata_parse_field_type:
 * \param m metadata context to extract information from
 * \param ptr pointer to the field signature
 * \param rptr pointer updated to match the end of the decoded stream
 *
 * Parses the field signature, and returns the type information for it. 
 *
 * \returns The \c MonoType that was extracted from \p ptr .
 */
MonoType *
mono_metadata_parse_field_type (MonoImage *m, short field_flags, const char *ptr, const char **rptr)
{
        ERROR_DECL (error);
        MonoType * type = mono_metadata_parse_type_internal (m, NULL, field_flags, FALSE, ptr, rptr, error);
        mono_error_cleanup (error);
        return type;
}

/**
 * mono_metadata_parse_param:
 * \param m metadata context to extract information from
 * \param ptr pointer to the param signature
 * \param rptr pointer updated to match the end of the decoded stream
 *
 * Parses the param signature, and returns the type information for it. 
 *
 * \returns The \c MonoType that was extracted from \p ptr .
 */
MonoType *
mono_metadata_parse_param (MonoImage *m, const char *ptr, const char **rptr)
{
        ERROR_DECL (error);
        MonoType * type = mono_metadata_parse_type_internal (m, NULL, 0, FALSE, ptr, rptr, error);
        mono_error_cleanup (error);
        return type;
}

/**
 * mono_metadata_token_from_dor:
 * \param dor_token A \c TypeDefOrRef coded index
 *
 * \p dor_token is a \c TypeDefOrRef coded index: it contains either
 * a \c TypeDef, \c TypeRef or \c TypeSpec in the lower bits, and the upper
 * bits contain an index into the table.
 *
 * \returns an expanded token
 */
guint32
mono_metadata_token_from_dor (guint32 dor_index)
{
        guint32 table, idx;

        table = dor_index & 0x03;
        idx = dor_index >> 2;

        switch (table){
        case 0: /* TypeDef */
                return MONO_TOKEN_TYPE_DEF | idx;
        case 1: /* TypeRef */
                return MONO_TOKEN_TYPE_REF | idx;
        case 2: /* TypeSpec */
                return MONO_TOKEN_TYPE_SPEC | idx;
        default:
                g_assert_not_reached ();
        }

        return 0;
}

/*
 * We use this to pass context information to the row locator
 */
typedef struct {
        int idx;                        /* The index that we are trying to locate */
        int col_idx;            /* The index in the row where idx may be stored */
        MonoTableInfo *t;       /* pointer to the table */
        guint32 result;
} locator_t;

/*
 * How the row locator works.
 *
 *   Table A
 *   ___|___
 *   ___|___         Table B
 *   ___|___------>  _______
 *   ___|___         _______
 *   
 * A column in the rows of table A references an index in table B.
 * For example A may be the TYPEDEF table and B the METHODDEF table.
 * 
 * Given an index in table B we want to get the row in table A
 * where the column n references our index in B.
 *
 * In the locator_t structure:
 *      t is table A
 *      col_idx is the column number
 *      index is the index in table B
 *      result will be the index in table A
 *
 * Examples:
 * Table A              Table B         column (in table A)
 * TYPEDEF              METHODDEF   MONO_TYPEDEF_METHOD_LIST
 * TYPEDEF              FIELD           MONO_TYPEDEF_FIELD_LIST
 * PROPERTYMAP  PROPERTY        MONO_PROPERTY_MAP_PROPERTY_LIST
 * INTERFIMPL   TYPEDEF         MONO_INTERFACEIMPL_CLASS
 * METHODSEM    PROPERTY        ASSOCIATION (encoded index)
 *
 * Note that we still don't support encoded indexes.
 *
 */
static int
typedef_locator (const void *a, const void *b)
{
        locator_t *loc = (locator_t *) a;
        const char *bb = (const char *) b;
        int typedef_index = (bb - loc->t->base) / loc->t->row_size;
        guint32 col, col_next;

        col = mono_metadata_decode_row_col (loc->t, typedef_index, loc->col_idx);

        if (loc->idx < col)
                return -1;

        /*
         * Need to check that the next row is valid.
         */
        if (typedef_index + 1 < loc->t->rows) {
                col_next = mono_metadata_decode_row_col (loc->t, typedef_index + 1, loc->col_idx);
                if (loc->idx >= col_next)
                        return 1;

                if (col == col_next)
                        return 1; 
        }

        loc->result = typedef_index;
        
        return 0;
}

static int
table_locator (const void *a, const void *b)
{
        locator_t *loc = (locator_t *) a;
        const char *bb = (const char *) b;
        guint32 table_index = (bb - loc->t->base) / loc->t->row_size;
        guint32 col;
        
        col = mono_metadata_decode_row_col (loc->t, table_index, loc->col_idx);

        if (loc->idx == col) {
                loc->result = table_index;
                return 0;
        }
        if (loc->idx < col)
                return -1;
        else 
                return 1;
}

static int
declsec_locator (const void *a, const void *b)
{
        locator_t *loc = (locator_t *) a;
        const char *bb = (const char *) b;
        guint32 table_index = (bb - loc->t->base) / loc->t->row_size;
        guint32 col;

        col = mono_metadata_decode_row_col (loc->t, table_index, loc->col_idx);

        if (loc->idx == col) {
                loc->result = table_index;
                return 0;
        }
        if (loc->idx < col)
                return -1;
        else
                return 1;
}

/**
 * search_ptr_table:
 *
 *  Return the 1-based row index in TABLE, which must be one of the *Ptr tables, 
 * which contains IDX.
 */
static guint32
search_ptr_table (MonoImage *image, int table, int idx)
{
        MonoTableInfo *ptrdef = &image->tables [table];
        int i;

        /* Use a linear search to find our index in the table */
        for (i = 0; i < ptrdef->rows; i ++)
                /* All the Ptr tables have the same structure */
                if (mono_metadata_decode_row_col (ptrdef, i, 0) == idx)
                        break;

        if (i < ptrdef->rows)
                return i + 1;
        else
                return idx;
}

/**
 * mono_metadata_typedef_from_field:
 * \param meta metadata context
 * \param index FieldDef token
 *
 * \returns the 1-based index into the \c TypeDef table of the type that
 * declared the field described by \p index, or 0 if not found.
 */
guint32
mono_metadata_typedef_from_field (MonoImage *meta, guint32 index)
{
        MonoTableInfo *tdef = &meta->tables [MONO_TABLE_TYPEDEF];
        locator_t loc;

        if (!tdef->base)
                return 0;

        loc.idx = mono_metadata_token_index (index);
        loc.col_idx = MONO_TYPEDEF_FIELD_LIST;
        loc.t = tdef;

        if (meta->uncompressed_metadata)
                loc.idx = search_ptr_table (meta, MONO_TABLE_FIELD_POINTER, loc.idx);

        if (!mono_binary_search (&loc, tdef->base, tdef->rows, tdef->row_size, typedef_locator))
                return 0;

        /* loc_result is 0..1, needs to be mapped to table index (that is +1) */
        return loc.result + 1;
}

/**
 * mono_metadata_typedef_from_method:
 * \param meta metadata context
 * \param index \c MethodDef token
 * \returns the 1-based index into the \c TypeDef table of the type that
 * declared the method described by \p index.  0 if not found.
 */
guint32
mono_metadata_typedef_from_method (MonoImage *meta, guint32 index)
{
        MonoTableInfo *tdef = &meta->tables [MONO_TABLE_TYPEDEF];
        locator_t loc;
        
        if (!tdef->base)
                return 0;

        loc.idx = mono_metadata_token_index (index);
        loc.col_idx = MONO_TYPEDEF_METHOD_LIST;
        loc.t = tdef;

        if (meta->uncompressed_metadata)
                loc.idx = search_ptr_table (meta, MONO_TABLE_METHOD_POINTER, loc.idx);

        if (!mono_binary_search (&loc, tdef->base, tdef->rows, tdef->row_size, typedef_locator))
                return 0;

        /* loc_result is 0..1, needs to be mapped to table index (that is +1) */
        return loc.result + 1;
}

/**
 * mono_metadata_interfaces_from_typedef_full:
 * \param meta metadata context
 * \param index typedef token
 * \param interfaces Out parameter used to store the interface array
 * \param count Out parameter used to store the number of interfaces
 * \param heap_alloc_result if TRUE the result array will be \c g_malloc'd
 * \param context The generic context
 * \param error set on error
 * 
 * The array of interfaces that the \p index typedef token implements is returned in
 * \p interfaces. The number of elements in the array is returned in \p count.
 *
 * \returns \c TRUE on success, \c FALSE on failure and sets \p error.
 */
gboolean
mono_metadata_interfaces_from_typedef_full (MonoImage *meta, guint32 index, MonoClass ***interfaces, guint *count, gboolean heap_alloc_result, MonoGenericContext *context, MonoError *error)
{
        MonoTableInfo *tdef = &meta->tables [MONO_TABLE_INTERFACEIMPL];
        locator_t loc;
        guint32 start, pos;
        guint32 cols [MONO_INTERFACEIMPL_SIZE];
        MonoClass **result;

        *interfaces = NULL;
        *count = 0;

        error_init (error);

        if (!tdef->base)
                return TRUE;

        loc.idx = mono_metadata_token_index (index);
        loc.col_idx = MONO_INTERFACEIMPL_CLASS;
        loc.t = tdef;

        if (!mono_binary_search (&loc, tdef->base, tdef->rows, tdef->row_size, table_locator))
                return TRUE;

        start = loc.result;
        /*
         * We may end up in the middle of the rows... 
         */
        while (start > 0) {
                if (loc.idx == mono_metadata_decode_row_col (tdef, start - 1, MONO_INTERFACEIMPL_CLASS))
                        start--;
                else
                        break;
        }
        pos = start;
        while (pos < tdef->rows) {
                mono_metadata_decode_row (tdef, pos, cols, MONO_INTERFACEIMPL_SIZE);
                if (cols [MONO_INTERFACEIMPL_CLASS] != loc.idx)
                        break;
                ++pos;
        }

        if (heap_alloc_result)
                result = g_new0 (MonoClass*, pos - start);
        else
                result = (MonoClass **)mono_image_alloc0 (meta, sizeof (MonoClass*) * (pos - start));

        pos = start;
        while (pos < tdef->rows) {
                MonoClass *iface;
                
                mono_metadata_decode_row (tdef, pos, cols, MONO_INTERFACEIMPL_SIZE);
                if (cols [MONO_INTERFACEIMPL_CLASS] != loc.idx)
                        break;
                iface = mono_class_get_and_inflate_typespec_checked (
                        meta, mono_metadata_token_from_dor (cols [MONO_INTERFACEIMPL_INTERFACE]), context, error);
                if (iface == NULL)
                        return FALSE;
                result [pos - start] = iface;
                ++pos;
        }
        *count = pos - start;
        *interfaces = result;
        return TRUE;
}

/**
 * mono_metadata_interfaces_from_typedef:
 * \param meta metadata context
 * \param index typedef token
 * \param count Out parameter used to store the number of interfaces
 * 
 * The array of interfaces that the \p index typedef token implements is returned in
 * \p interfaces. The number of elements in the array is returned in \p count. The returned
 * array is allocated with \c g_malloc and the caller must free it.
 *
 * LOCKING: Acquires the loader lock .
 *
 * \returns the interface array on success, NULL on failure.
 */
MonoClass**
mono_metadata_interfaces_from_typedef (MonoImage *meta, guint32 index, guint *count)
{
        ERROR_DECL (error);
        MonoClass **interfaces = NULL;
        gboolean rv;

        rv = mono_metadata_interfaces_from_typedef_full (meta, index, &interfaces, count, TRUE, NULL, error);
        mono_error_assert_ok (error);
        if (rv)
                return interfaces;
        else
                return NULL;
}

/**
 * mono_metadata_nested_in_typedef:
 * \param meta metadata context
 * \param index typedef token
 * \returns the 1-based index into the TypeDef table of the type
 * where the type described by \p index is nested.
 * Returns 0 if \p index describes a non-nested type.
 */
guint32
mono_metadata_nested_in_typedef (MonoImage *meta, guint32 index)
{
        MonoTableInfo *tdef = &meta->tables [MONO_TABLE_NESTEDCLASS];
        locator_t loc;
        
        if (!tdef->base)
                return 0;

        loc.idx = mono_metadata_token_index (index);
        loc.col_idx = MONO_NESTED_CLASS_NESTED;
        loc.t = tdef;

        if (!mono_binary_search (&loc, tdef->base, tdef->rows, tdef->row_size, table_locator))
                return 0;

        /* loc_result is 0..1, needs to be mapped to table index (that is +1) */
        return mono_metadata_decode_row_col (tdef, loc.result, MONO_NESTED_CLASS_ENCLOSING) | MONO_TOKEN_TYPE_DEF;
}

/**
 * mono_metadata_nesting_typedef:
 * \param meta metadata context
 * \param index typedef token
 * \returns the 1-based index into the \c TypeDef table of the first type
 * that is nested inside the type described by \p index. The search starts at
 * \p start_index. Returns 0 if no such type is found.
 */
guint32
mono_metadata_nesting_typedef (MonoImage *meta, guint32 index, guint32 start_index)
{
        MonoTableInfo *tdef = &meta->tables [MONO_TABLE_NESTEDCLASS];
        guint32 start;
        guint32 class_index = mono_metadata_token_index (index);
        
        if (!tdef->base)
                return 0;

        start = start_index;

        while (start <= tdef->rows) {
                if (class_index == mono_metadata_decode_row_col (tdef, start - 1, MONO_NESTED_CLASS_ENCLOSING))
                        break;
                else
                        start++;
        }

        if (start > tdef->rows)
                return 0;
        else
                return start;
}

/**
 * mono_metadata_packing_from_typedef:
 * \param meta metadata context
 * \param index token representing a type
 * \returns the info stored in the \c ClassLayout table for the given typedef token
 * into the \p packing and \p size pointers.
 * Returns 0 if the info is not found.
 */
guint32
mono_metadata_packing_from_typedef (MonoImage *meta, guint32 index, guint32 *packing, guint32 *size)
{
        MonoTableInfo *tdef = &meta->tables [MONO_TABLE_CLASSLAYOUT];
        locator_t loc;
        guint32 cols [MONO_CLASS_LAYOUT_SIZE];
        
        if (!tdef->base)
                return 0;

        loc.idx = mono_metadata_token_index (index);
        loc.col_idx = MONO_CLASS_LAYOUT_PARENT;
        loc.t = tdef;

        if (!mono_binary_search (&loc, tdef->base, tdef->rows, tdef->row_size, table_locator))
                return 0;

        mono_metadata_decode_row (tdef, loc.result, cols, MONO_CLASS_LAYOUT_SIZE);
        if (packing)
                *packing = cols [MONO_CLASS_LAYOUT_PACKING_SIZE];
        if (size)
                *size = cols [MONO_CLASS_LAYOUT_CLASS_SIZE];

        /* loc_result is 0..1, needs to be mapped to table index (that is +1) */
        return loc.result + 1;
}

/**
 * mono_metadata_custom_attrs_from_index:
 * \param meta metadata context
 * \param index token representing the parent
 * \returns: the 1-based index into the \c CustomAttribute table of the first 
 * attribute which belongs to the metadata object described by \p index.
 * Returns 0 if no such attribute is found.
 */
guint32
mono_metadata_custom_attrs_from_index (MonoImage *meta, guint32 index)
{
        MonoTableInfo *tdef = &meta->tables [MONO_TABLE_CUSTOMATTRIBUTE];
        locator_t loc;
        
        if (!tdef->base)
                return 0;

        loc.idx = index;
        loc.col_idx = MONO_CUSTOM_ATTR_PARENT;
        loc.t = tdef;

        /* FIXME: Index translation */

        if (!mono_binary_search (&loc, tdef->base, tdef->rows, tdef->row_size, table_locator))
                return 0;

        /* Find the first entry by searching backwards */
        while ((loc.result > 0) && (mono_metadata_decode_row_col (tdef, loc.result - 1, MONO_CUSTOM_ATTR_PARENT) == index))
                loc.result --;

        /* loc_result is 0..1, needs to be mapped to table index (that is +1) */
        return loc.result + 1;
}

/**
 * mono_metadata_declsec_from_index:
 * \param meta metadata context
 * \param index token representing the parent
 * \returns the 0-based index into the \c DeclarativeSecurity table of the first 
 * attribute which belongs to the metadata object described by \p index.
 * Returns \c -1 if no such attribute is found.
 */
guint32
mono_metadata_declsec_from_index (MonoImage *meta, guint32 index)
{
        MonoTableInfo *tdef = &meta->tables [MONO_TABLE_DECLSECURITY];
        locator_t loc;

        if (!tdef->base)
                return -1;

        loc.idx = index;
        loc.col_idx = MONO_DECL_SECURITY_PARENT;
        loc.t = tdef;

        if (!mono_binary_search (&loc, tdef->base, tdef->rows, tdef->row_size, declsec_locator))
                return -1;

        /* Find the first entry by searching backwards */
        while ((loc.result > 0) && (mono_metadata_decode_row_col (tdef, loc.result - 1, MONO_DECL_SECURITY_PARENT) == index))
                loc.result --;

        return loc.result;
}

/*
 * mono_metadata_localscope_from_methoddef:
 * @meta: metadata context
 * @index: methoddef index
 * 
 * Returns: the 1-based index into the LocalScope table of the first
 * scope which belongs to the method described by @index.
 * Returns 0 if no such row is found.
 */
guint32
mono_metadata_localscope_from_methoddef (MonoImage *meta, guint32 index)
{
        MonoTableInfo *tdef = &meta->tables [MONO_TABLE_LOCALSCOPE];
        locator_t loc;

        if (!tdef->base)
                return 0;

        loc.idx = index;
        loc.col_idx = MONO_LOCALSCOPE_METHOD;
        loc.t = tdef;

        if (!mono_binary_search (&loc, tdef->base, tdef->rows, tdef->row_size, table_locator))
                return 0;

        /* Find the first entry by searching backwards */
        while ((loc.result > 0) && (mono_metadata_decode_row_col (tdef, loc.result - 1, MONO_LOCALSCOPE_METHOD) == index))
                loc.result --;

        return loc.result + 1;
}

#ifdef DEBUG
static void
mono_backtrace (int limit)
{
        void *array[limit];
        char **names;
        int i;
        backtrace (array, limit);
        names = backtrace_symbols (array, limit);
        for (i =0; i < limit; ++i) {
                g_print ("\t%s\n", names [i]);
        }
        g_free (names);
}
#endif

static int i8_align;

/*
 * mono_type_set_alignment:
 *
 *   Set the alignment used by runtime to layout fields etc. of type TYPE to ALIGN.
 * This should only be used in AOT mode since the resulting layout will not match the
 * host abi layout.
 */
void
mono_type_set_alignment (MonoTypeEnum type, int align)
{
        /* Support only a few types whose alignment is abi dependent */
        switch (type) {
        case MONO_TYPE_I8:
                i8_align = align;
                break;
        default:
                g_assert_not_reached ();
                break;
        }
}

/**
 * mono_type_size:
 * \param t the type to return the size of
 * \returns The number of bytes required to hold an instance of this
 * type in memory
 */
int
mono_type_size (MonoType *t, int *align)
{
        MonoTypeEnum simple_type;

        if (!t) {
                *align = 1;
                return 0;
        }
        if (t->byref) {
                *align = MONO_ABI_ALIGNOF (gpointer);
                return MONO_ABI_SIZEOF (gpointer);
        }

        simple_type = t->type;
 again:
        switch (simple_type) {
        case MONO_TYPE_VOID:
                *align = 1;
                return 0;
        case MONO_TYPE_BOOLEAN:
                *align = MONO_ABI_ALIGNOF (gint8);
                return 1;
        case MONO_TYPE_I1:
        case MONO_TYPE_U1:
                *align = MONO_ABI_ALIGNOF (gint8);
                return 1;
        case MONO_TYPE_CHAR:
        case MONO_TYPE_I2:
        case MONO_TYPE_U2:
                *align = MONO_ABI_ALIGNOF (gint16);
                return 2;               
        case MONO_TYPE_I4:
        case MONO_TYPE_U4:
                *align = MONO_ABI_ALIGNOF (gint32);
                return 4;
        case MONO_TYPE_R4:
                *align = MONO_ABI_ALIGNOF (float);
                return 4;
        case MONO_TYPE_I8:
        case MONO_TYPE_U8:
                *align = MONO_ABI_ALIGNOF (gint64);
                return 8;               
        case MONO_TYPE_R8:
                *align = MONO_ABI_ALIGNOF (double);
                return 8;               
        case MONO_TYPE_I:
        case MONO_TYPE_U:
                *align = MONO_ABI_ALIGNOF (gpointer);
                return MONO_ABI_SIZEOF (gpointer);
        case MONO_TYPE_VALUETYPE: {
                if (m_class_is_enumtype (t->data.klass))
                        return mono_type_size (mono_class_enum_basetype_internal (t->data.klass), align);
                else
                        return mono_class_value_size (t->data.klass, (guint32*)align);
        }
        case MONO_TYPE_STRING:
        case MONO_TYPE_OBJECT:
        case MONO_TYPE_CLASS:
        case MONO_TYPE_SZARRAY:
        case MONO_TYPE_PTR:
        case MONO_TYPE_FNPTR:
        case MONO_TYPE_ARRAY:
                *align = MONO_ABI_ALIGNOF (gpointer);
                return MONO_ABI_SIZEOF (gpointer);
        case MONO_TYPE_TYPEDBYREF:
                return mono_class_value_size (mono_defaults.typed_reference_class, (guint32*)align);
        case MONO_TYPE_GENERICINST: {
                MonoGenericClass *gclass = t->data.generic_class;
                MonoClass *container_class = gclass->container_class;

                // g_assert (!gclass->inst->is_open);

                if (m_class_is_valuetype (container_class)) {
                        if (m_class_is_enumtype (container_class))
                                return mono_type_size (mono_class_enum_basetype_internal (container_class), align);
                        else
                                return mono_class_value_size (mono_class_from_mono_type_internal (t), (guint32*)align);
                } else {
                        *align = MONO_ABI_ALIGNOF (gpointer);
                        return MONO_ABI_SIZEOF (gpointer);
                }
        }
        case MONO_TYPE_VAR:
        case MONO_TYPE_MVAR:
                if (!t->data.generic_param->gshared_constraint || t->data.generic_param->gshared_constraint->type == MONO_TYPE_VALUETYPE) {
                        *align = MONO_ABI_ALIGNOF (gpointer);
                        return MONO_ABI_SIZEOF (gpointer);
                } else {
                        /* The gparam can only match types given by gshared_constraint */
                        return mono_type_size (t->data.generic_param->gshared_constraint, align);
                        goto again;
                }
        default:
                g_error ("mono_type_size: type 0x%02x unknown", t->type);
        }
        return 0;
}

/**
 * mono_type_stack_size:
 * \param t the type to return the size it uses on the stack
 * \returns The number of bytes required to hold an instance of this
 * type on the runtime stack
 */
int
mono_type_stack_size (MonoType *t, int *align)
{
        return mono_type_stack_size_internal (t, align, FALSE);
}

int
mono_type_stack_size_internal (MonoType *t, int *align, gboolean allow_open)
{
        int tmp;
        MonoTypeEnum simple_type;
        int stack_slot_size = TARGET_SIZEOF_VOID_P;
        int stack_slot_align = TARGET_SIZEOF_VOID_P;

        g_assert (t != NULL);

        if (!align)
                align = &tmp;

        if (t->byref) {
                *align = stack_slot_align;
                return stack_slot_size;
        }

        simple_type = t->type;
        switch (simple_type) {
        case MONO_TYPE_BOOLEAN:
        case MONO_TYPE_CHAR:
        case MONO_TYPE_I1:
        case MONO_TYPE_U1:
        case MONO_TYPE_I2:
        case MONO_TYPE_U2:
        case MONO_TYPE_I4:
        case MONO_TYPE_U4:
        case MONO_TYPE_I:
        case MONO_TYPE_U:
        case MONO_TYPE_STRING:
        case MONO_TYPE_OBJECT:
        case MONO_TYPE_CLASS:
        case MONO_TYPE_SZARRAY:
        case MONO_TYPE_PTR:
        case MONO_TYPE_FNPTR:
        case MONO_TYPE_ARRAY:
                *align = stack_slot_align;
                return stack_slot_size;
        case MONO_TYPE_VAR:
        case MONO_TYPE_MVAR:
                g_assert (allow_open);
                if (!t->data.generic_param->gshared_constraint || t->data.generic_param->gshared_constraint->type == MONO_TYPE_VALUETYPE) {
                        *align = stack_slot_align;
                        return stack_slot_size;
                } else {
                        /* The gparam can only match types given by gshared_constraint */
                        return mono_type_stack_size_internal (t->data.generic_param->gshared_constraint, align, allow_open);
                }
        case MONO_TYPE_TYPEDBYREF:
                *align = stack_slot_align;
                return stack_slot_size * 3;
        case MONO_TYPE_R4:
                *align = MONO_ABI_ALIGNOF (float);
                return sizeof (float);          
        case MONO_TYPE_I8:
        case MONO_TYPE_U8:
                *align = MONO_ABI_ALIGNOF (gint64);
                return sizeof (gint64);         
        case MONO_TYPE_R8:
                *align = MONO_ABI_ALIGNOF (double);
                return sizeof (double);
        case MONO_TYPE_VALUETYPE: {
                guint32 size;

                if (m_class_is_enumtype (t->data.klass))
                        return mono_type_stack_size_internal (mono_class_enum_basetype_internal (t->data.klass), align, allow_open);
                else {
                        size = mono_class_value_size (t->data.klass, (guint32*)align);

                        *align = *align + stack_slot_align - 1;
                        *align &= ~(stack_slot_align - 1);

                        size += stack_slot_size - 1;
                        size &= ~(stack_slot_size - 1);

                        return size;
                }
        }
        case MONO_TYPE_GENERICINST: {
                MonoGenericClass *gclass = t->data.generic_class;
                MonoClass *container_class = gclass->container_class;

                if (!allow_open)
                        g_assert (!gclass->context.class_inst->is_open);

                if (m_class_is_valuetype (container_class)) {
                        if (m_class_is_enumtype (container_class))
                                return mono_type_stack_size_internal (mono_class_enum_basetype_internal (container_class), align, allow_open);
                        else {
                                guint32 size = mono_class_value_size (mono_class_from_mono_type_internal (t), (guint32*)align);

                                *align = *align + stack_slot_align - 1;
                                *align &= ~(stack_slot_align - 1);

                                size += stack_slot_size - 1;
                                size &= ~(stack_slot_size - 1);

                                return size;
                        }
                } else {
                        *align = stack_slot_align;
                        return stack_slot_size;
                }
        }
        default:
                g_error ("type 0x%02x unknown", t->type);
        }
        return 0;
}

gboolean
mono_type_generic_inst_is_valuetype (MonoType *type)
{
        g_assert (type->type == MONO_TYPE_GENERICINST);
        return m_class_is_valuetype (type->data.generic_class->container_class);
}

/**
 * mono_metadata_generic_class_is_valuetype:
 */
gboolean
mono_metadata_generic_class_is_valuetype (MonoGenericClass *gclass)
{
        return m_class_is_valuetype (gclass->container_class);
}

static gboolean
_mono_metadata_generic_class_equal (const MonoGenericClass *g1, const MonoGenericClass *g2, gboolean signature_only)
{
        MonoGenericInst *i1 = g1->context.class_inst;
        MonoGenericInst *i2 = g2->context.class_inst;

        if (g1->is_dynamic != g2->is_dynamic)
                return FALSE;
        if (!mono_metadata_class_equal (g1->container_class, g2->container_class, signature_only))
                return FALSE;
        if (!mono_generic_inst_equal_full (i1, i2, signature_only))
                return FALSE;
        return g1->is_tb_open == g2->is_tb_open;
}

static gboolean
_mono_metadata_generic_class_container_equal (const MonoGenericClass *g1, MonoClass *c2, gboolean signature_only)
{
        MonoGenericInst *i1 = g1->context.class_inst;
        MonoGenericInst *i2 = mono_class_get_generic_container (c2)->context.class_inst;

        if (!mono_metadata_class_equal (g1->container_class, c2, signature_only))
                return FALSE;
        if (!mono_generic_inst_equal_full (i1, i2, signature_only))
                return FALSE;
        return !g1->is_tb_open;
}

guint
mono_metadata_generic_context_hash (const MonoGenericContext *context)
{
        /* FIXME: check if this seed is good enough */
        guint hash = 0xc01dfee7;
        if (context->class_inst)
                hash = ((hash << 5) - hash) ^ mono_metadata_generic_inst_hash (context->class_inst);
        if (context->method_inst)
                hash = ((hash << 5) - hash) ^ mono_metadata_generic_inst_hash (context->method_inst);
        return hash;
}

gboolean
mono_metadata_generic_context_equal (const MonoGenericContext *g1, const MonoGenericContext *g2)
{
        return g1->class_inst == g2->class_inst && g1->method_inst == g2->method_inst;
}

/*
 * mono_metadata_str_hash:
 *
 *   This should be used instead of g_str_hash for computing hash codes visible
 * outside this module, since g_str_hash () is not guaranteed to be stable
 * (its not the same in eglib for example).
 */
guint
mono_metadata_str_hash (gconstpointer v1)
{
        /* Same as g_str_hash () in glib */
        /* note: signed/unsigned char matters - we feed UTF-8 to this function, so the high bit will give diferent results if we don't match. */
        unsigned char *p = (unsigned char *) v1;
        guint hash = *p;

        while (*p++) {
                if (*p)
                        hash = (hash << 5) - hash + *p;
        }

        return hash;
} 

/**
 * mono_metadata_type_hash:
 * \param t1 a type
 * Computes a hash value for \p t1 to be used in \c GHashTable.
 * The returned hash is guaranteed to be the same across executions.
 */
guint
mono_metadata_type_hash (MonoType *t1)
{
        guint hash = t1->type;

        hash |= t1->byref << 6; /* do not collide with t1->type values */
        switch (t1->type) {
        case MONO_TYPE_VALUETYPE:
        case MONO_TYPE_CLASS:
        case MONO_TYPE_SZARRAY: {
                MonoClass *klass = t1->data.klass;
                /*
                 * Dynamic classes must not be hashed on their type since it can change
                 * during runtime. For example, if we hash a reference type that is
                 * later made into a valuetype.
                 *
                 * This is specially problematic with generic instances since they are
                 * inserted in a bunch of hash tables before been finished.
                 */
                if (image_is_dynamic (m_class_get_image (klass)))
                        return (t1->byref << 6) | mono_metadata_str_hash (m_class_get_name (klass));
                return ((hash << 5) - hash) ^ mono_metadata_str_hash (m_class_get_name (klass));
        }
        case MONO_TYPE_PTR:
                return ((hash << 5) - hash) ^ mono_metadata_type_hash (t1->data.type);
        case MONO_TYPE_ARRAY:
                return ((hash << 5) - hash) ^ mono_metadata_type_hash (m_class_get_byval_arg (t1->data.array->eklass));
        case MONO_TYPE_GENERICINST:
                return ((hash << 5) - hash) ^ mono_generic_class_hash (t1->data.generic_class);
        case MONO_TYPE_VAR:
        case MONO_TYPE_MVAR:
                return ((hash << 5) - hash) ^ mono_metadata_generic_param_hash (t1->data.generic_param);
        default:
                return hash;
        }
}

guint
mono_metadata_generic_param_hash (MonoGenericParam *p)
{
        guint hash;
        MonoGenericParamInfo *info;

        hash = (mono_generic_param_num (p) << 2);
        if (p->gshared_constraint)
                hash = ((hash << 5) - hash) ^ mono_metadata_type_hash (p->gshared_constraint);
        info = mono_generic_param_info (p);
        /* Can't hash on the owner klass/method, since those might not be set when this is called */
        if (!p->owner->is_anonymous)
                hash = ((hash << 5) - hash) ^ info->token;
        return hash;
}

static gboolean
mono_metadata_generic_param_equal_internal (MonoGenericParam *p1, MonoGenericParam *p2, gboolean signature_only)
{
        if (p1 == p2)
                return TRUE;
        if (mono_generic_param_num (p1) != mono_generic_param_num (p2))
                return FALSE;
        if (p1->gshared_constraint && p2->gshared_constraint) {
                if (!mono_metadata_type_equal (p1->gshared_constraint, p2->gshared_constraint))
                        return FALSE;
        } else {
                if (p1->gshared_constraint != p2->gshared_constraint)
                        return FALSE;
        }

        /*
         * We have to compare the image as well because if we didn't,
         * the generic_inst_cache lookup wouldn't care about the image
         * of generic params, so what could happen is that a generic
         * inst with params from image A is put into the cache, then
         * image B gets that generic inst from the cache, image A is
         * unloaded, so the inst is deleted, but image B still retains
         * a pointer to it.
         */
        if (mono_generic_param_owner (p1) == mono_generic_param_owner (p2))
                return TRUE;

        /*
         * If `signature_only' is true, we're comparing two (method) signatures.
         * In this case, the owner of two type parameters doesn't need to match.
         */

        return signature_only;
}

gboolean
mono_metadata_generic_param_equal (MonoGenericParam *p1, MonoGenericParam *p2)
{
        return mono_metadata_generic_param_equal_internal (p1, p2, TRUE);
}

static gboolean
mono_metadata_class_equal (MonoClass *c1, MonoClass *c2, gboolean signature_only)
{
        if (c1 == c2)
                return TRUE;
        if (mono_class_is_ginst (c1) && mono_class_is_ginst (c2))
                return _mono_metadata_generic_class_equal (mono_class_get_generic_class (c1), mono_class_get_generic_class (c2), signature_only);
        if (mono_class_is_ginst (c1) && mono_class_is_gtd (c2))
                return _mono_metadata_generic_class_container_equal (mono_class_get_generic_class (c1), c2, signature_only);
        if (mono_class_is_gtd (c1) && mono_class_is_ginst (c2))
                return _mono_metadata_generic_class_container_equal (mono_class_get_generic_class (c2), c1, signature_only);
        MonoType *c1_type = m_class_get_byval_arg (c1);
        MonoType *c2_type = m_class_get_byval_arg (c2);
        if ((c1_type->type == MONO_TYPE_VAR) && (c2_type->type == MONO_TYPE_VAR))
                return mono_metadata_generic_param_equal_internal (
                        c1_type->data.generic_param, c2_type->data.generic_param, signature_only);
        if ((c1_type->type == MONO_TYPE_MVAR) && (c2_type->type == MONO_TYPE_MVAR))
                return mono_metadata_generic_param_equal_internal (
                        c1_type->data.generic_param, c2_type->data.generic_param, signature_only);
        if (signature_only &&
            (c1_type->type == MONO_TYPE_SZARRAY) && (c2_type->type == MONO_TYPE_SZARRAY))
                return mono_metadata_class_equal (c1_type->data.klass, c2_type->data.klass, signature_only);
        if (signature_only &&
            (c1_type->type == MONO_TYPE_ARRAY) && (c2_type->type == MONO_TYPE_ARRAY))
                return do_mono_metadata_type_equal (c1_type, c2_type, signature_only);
        return FALSE;
}

static gboolean
mono_metadata_fnptr_equal (MonoMethodSignature *s1, MonoMethodSignature *s2, gboolean signature_only)
{
        gpointer iter1 = 0, iter2 = 0;

        if (s1 == s2)
                return TRUE;
        if (s1->call_convention != s2->call_convention)
                return FALSE;
        if (s1->sentinelpos != s2->sentinelpos)
                return FALSE;
        if (s1->hasthis != s2->hasthis)
                return FALSE;
        if (s1->explicit_this != s2->explicit_this)
                return FALSE;
        if (! do_mono_metadata_type_equal (s1->ret, s2->ret, signature_only))
                return FALSE;
        if (s1->param_count != s2->param_count)
                return FALSE;

        while (TRUE) {
                MonoType *t1 = mono_signature_get_params (s1, &iter1);
                MonoType *t2 = mono_signature_get_params (s2, &iter2);

                if (t1 == NULL || t2 == NULL)
                        return (t1 == t2);
                if (! do_mono_metadata_type_equal (t1, t2, signature_only))
                        return FALSE;
        }
}

static gboolean
mono_metadata_custom_modifiers_equal (MonoType *t1, MonoType *t2, gboolean signature_only)
{
        // ECMA 335, 7.1.1:
        // The CLI itself shall treat required and optional modifiers in the same manner.
        // Two signatures that differ only by the addition of a custom modifier
        // (required or optional) shall not be considered to match.
        int count = mono_type_custom_modifier_count (t1);
        if (count != mono_type_custom_modifier_count (t2))
                return FALSE;

        for (int i=0; i < count; i++) {
                // FIXME: propagate error to caller
                ERROR_DECL (error);
                gboolean cm1_required, cm2_required;

                MonoType *cm1_type = mono_type_get_custom_modifier (t1, i, &cm1_required, error);
                mono_error_assert_ok (error);
                MonoType *cm2_type = mono_type_get_custom_modifier (t2, i, &cm2_required, error);
                mono_error_assert_ok (error);

                if (cm1_required != cm2_required)
                        return FALSE;

                if (!do_mono_metadata_type_equal (cm1_type, cm2_type, signature_only))
                        return FALSE;
        }
        return TRUE;
}

/*
 * mono_metadata_type_equal:
 * @t1: a type
 * @t2: another type
 * @signature_only: If true, treat ginsts as equal which are instantiated separately but have equal positional value
 *
 * Determine if @t1 and @t2 represent the same type.
 * Returns: #TRUE if @t1 and @t2 are equal.
 */
static gboolean
do_mono_metadata_type_equal (MonoType *t1, MonoType *t2, gboolean signature_only)
{
        if (t1->type != t2->type || t1->byref != t2->byref)
                return FALSE;

        gboolean cmod_reject = FALSE;

        if (t1->has_cmods != t2->has_cmods)
                cmod_reject = TRUE;
        else if (t1->has_cmods && t2->has_cmods) {
                cmod_reject = !mono_metadata_custom_modifiers_equal (t1, t2, signature_only);
        }

        gboolean result = FALSE;

        switch (t1->type) {
        case MONO_TYPE_VOID:
        case MONO_TYPE_BOOLEAN:
        case MONO_TYPE_CHAR:
        case MONO_TYPE_I1:
        case MONO_TYPE_U1:
        case MONO_TYPE_I2:
        case MONO_TYPE_U2:
        case MONO_TYPE_I4:
        case MONO_TYPE_U4:
        case MONO_TYPE_I8:
        case MONO_TYPE_U8:
        case MONO_TYPE_R4:
        case MONO_TYPE_R8:
        case MONO_TYPE_STRING:
        case MONO_TYPE_I:
        case MONO_TYPE_U:
        case MONO_TYPE_OBJECT:
        case MONO_TYPE_TYPEDBYREF:
                result = TRUE;
                break;
        case MONO_TYPE_VALUETYPE:
        case MONO_TYPE_CLASS:
        case MONO_TYPE_SZARRAY:
                result = mono_metadata_class_equal (t1->data.klass, t2->data.klass, signature_only);
                break;
        case MONO_TYPE_PTR:
                result = do_mono_metadata_type_equal (t1->data.type, t2->data.type, signature_only);
                break;
        case MONO_TYPE_ARRAY:
                if (t1->data.array->rank != t2->data.array->rank)
                        result = FALSE;
                else
                        result = mono_metadata_class_equal (t1->data.array->eklass, t2->data.array->eklass, signature_only);
                break;
        case MONO_TYPE_GENERICINST:
                result = _mono_metadata_generic_class_equal (
                        t1->data.generic_class, t2->data.generic_class, signature_only);
                break;
        case MONO_TYPE_VAR:
                result = mono_metadata_generic_param_equal_internal (
                        t1->data.generic_param, t2->data.generic_param, signature_only);
                break;
        case MONO_TYPE_MVAR:
                result = mono_metadata_generic_param_equal_internal (
                        t1->data.generic_param, t2->data.generic_param, signature_only);
                break;
        case MONO_TYPE_FNPTR:
                result = mono_metadata_fnptr_equal (t1->data.method, t2->data.method, signature_only);
                break;
        default:
                g_error ("implement type compare for %0x!", t1->type);
                return FALSE;
        }

        return result && !cmod_reject;
}

/**
 * mono_metadata_type_equal:
 */
gboolean
mono_metadata_type_equal (MonoType *t1, MonoType *t2)
{
        return do_mono_metadata_type_equal (t1, t2, FALSE);
}

/**
 * mono_metadata_type_equal_full:
 * \param t1 a type
 * \param t2 another type
 * \param signature_only if signature only comparison should be made
 *
 * Determine if \p t1 and \p t2 are signature compatible if \p signature_only is TRUE, otherwise
 * behaves the same way as mono_metadata_type_equal.
 * The function mono_metadata_type_equal(a, b) is just a shortcut for mono_metadata_type_equal_full(a, b, FALSE).
 * \returns TRUE if \p t1 and \p t2 are equal taking \p signature_only into account.
 */
gboolean
mono_metadata_type_equal_full (MonoType *t1, MonoType *t2, gboolean signature_only)
{
        return do_mono_metadata_type_equal (t1, t2, signature_only);
}

/**
 * mono_metadata_signature_equal:
 * \param sig1 a signature
 * \param sig2 another signature
 *
 * Determine if \p sig1 and \p sig2 represent the same signature, with the
 * same number of arguments and the same types.
 * \returns TRUE if \p sig1 and \p sig2 are equal.
 */
gboolean
mono_metadata_signature_equal (MonoMethodSignature *sig1, MonoMethodSignature *sig2)
{
        int i;

        if (sig1->hasthis != sig2->hasthis || sig1->param_count != sig2->param_count)
                return FALSE;

        if (sig1->generic_param_count != sig2->generic_param_count)
                return FALSE;

        /*
         * We're just comparing the signatures of two methods here:
         *
         * If we have two generic methods `void Foo<U> (U u)' and `void Bar<V> (V v)',
         * U and V are equal here.
         *
         * That's what the `signature_only' argument of do_mono_metadata_type_equal() is for.
         */

        for (i = 0; i < sig1->param_count; i++) { 
                MonoType *p1 = sig1->params[i];
                MonoType *p2 = sig2->params[i];
                
                /* if (p1->attrs != p2->attrs)
                        return FALSE;
                */
                if (!do_mono_metadata_type_equal (p1, p2, TRUE))
                        return FALSE;
        }

        if (!do_mono_metadata_type_equal (sig1->ret, sig2->ret, TRUE))
                return FALSE;
        return TRUE;
}

MonoType *
mono_type_get_custom_modifier (const MonoType *ty, uint8_t idx, gboolean *required, MonoError *error)
{
        g_assert (ty->has_cmods);
        if (mono_type_is_aggregate_mods (ty)) {
                MonoAggregateModContainer *amods = mono_type_get_amods (ty);
                g_assert (idx < amods->count);
                MonoSingleCustomMod *cmod = &amods->modifiers [idx];
                if (required)
                        *required = !!cmod->required;
                return cmod->type;
        } else {
                MonoCustomModContainer *cmods = mono_type_get_cmods (ty);
                g_assert (idx < cmods->count);
                MonoCustomMod *cmod = &cmods->modifiers [idx];
                if (required)
                        *required = !!cmod->required;
                MonoImage *image = cmods->image;
                uint32_t token = cmod->token;
                return mono_type_get_checked (image, token, NULL, error);
        }
}


/**
 * mono_metadata_type_dup:
 * \param image image to alloc memory from
 * \param original type to duplicate
 * \returns copy of type allocated from the image's mempool (or from the heap, if \p image is null).
 */
MonoType *
mono_metadata_type_dup (MonoImage *image, const MonoType *o)
{
        return mono_metadata_type_dup_with_cmods (image, o, o);
}

static void
deep_type_dup_fixup (MonoImage *image, MonoType *r, const MonoType *o);

static uint8_t
custom_modifier_copy (MonoAggregateModContainer *dest, uint8_t dest_offset, const MonoType *source)
{
        if (mono_type_is_aggregate_mods (source)) {
                MonoAggregateModContainer *src_cmods = mono_type_get_amods (source);
                memcpy (&dest->modifiers [dest_offset], &src_cmods->modifiers[0], src_cmods->count * sizeof (MonoSingleCustomMod));
                dest_offset += src_cmods->count;
        } else {
                MonoCustomModContainer *src_cmods = mono_type_get_cmods (source);
                for (int i = 0; i < src_cmods->count; i++) {
                        ERROR_DECL (error); // XXX FIXME: AK - propagate the error to the caller.
                        MonoSingleCustomMod *cmod = &dest->modifiers [dest_offset++];
                        cmod->type = mono_type_get_checked (src_cmods->image, src_cmods->modifiers [i].token, NULL, error);
                        mono_error_assert_ok (error);
                        cmod->required = src_cmods->modifiers [i].required;
                }
        }
        return dest_offset;
}

/* makes a dup of 'o' but also appends the custom modifiers from 'cmods_source' */
static MonoType *
do_metadata_type_dup_append_cmods (MonoImage *image, const MonoType *o, const MonoType *cmods_source)
{
        g_assert (o != cmods_source);
        g_assert (o->has_cmods);
        g_assert (cmods_source->has_cmods);
        if (!mono_type_is_aggregate_mods (o) &&
            !mono_type_is_aggregate_mods (cmods_source) &&
            mono_type_get_cmods (o)->image == mono_type_get_cmods (cmods_source)->image) {
                /* the uniform case: all the cmods are from the same image. */
                MonoCustomModContainer *o_cmods = mono_type_get_cmods (o);
                MonoCustomModContainer *extra_cmods = mono_type_get_cmods (cmods_source);
                uint8_t total_cmods = o_cmods->count + extra_cmods->count;
                gboolean aggregate = FALSE;
                size_t sizeof_dup = mono_sizeof_type_with_mods (total_cmods, aggregate);
                MonoType *r = image ? (MonoType *)mono_image_alloc0 (image, sizeof_dup) : (MonoType *)g_malloc0 (sizeof_dup);

                mono_type_with_mods_init (r, total_cmods, aggregate);

                /* copy the original type o, not including its modifiers */
                memcpy (r, o, mono_sizeof_type_with_mods (0, FALSE));
                deep_type_dup_fixup (image, r, o);

                /* The modifier order matters to Roslyn, they expect the extra cmods to come first:
                 *
                 * Suppose we substitute 'int32 modopt(IsLong)' for 'T' in 'void Test
                 * (T modopt(IsConst))'.  Roslyn expects the result to be 'void Test
                 * (int32 modopt(IsLong) modopt(IsConst))'.
                 *
                 * but! cmods are encoded in IL in reverse order, so 'int32 modopt(IsConst) modopt(IsLong)' is
                 * encoded as `cmod_opt [typeref IsLong] cmod_opt [typeref IsConst] I4`
                 * so in our array, extra_cmods (IsLong) come first, followed by o_cmods (IsConst)
                 *
                 * (Here 'o' is 'int32 modopt(IsLong)' and cmods_source is 'T modopt(IsConst)')
                 */
                /* append the modifiers from cmods_source and o */
                MonoCustomModContainer *r_container = mono_type_get_cmods (r);
                uint8_t dest_offset = 0;
                r_container->image = extra_cmods->image;

                memcpy (&r_container->modifiers [dest_offset], &o_cmods->modifiers [0], o_cmods->count * sizeof (MonoCustomMod));
                dest_offset += o_cmods->count;
                memcpy (&r_container->modifiers [dest_offset], &extra_cmods->modifiers [0], extra_cmods->count * sizeof (MonoCustomMod));
                dest_offset += extra_cmods->count;
                g_assert (dest_offset == total_cmods);

                return r;
        } else {
                /* The aggregate case: either o_cmods or extra_cmods has aggregate cmods, or they're both simple but from different images. */
                uint8_t total_cmods = 0;
                total_cmods += mono_type_custom_modifier_count (o);
                total_cmods += mono_type_custom_modifier_count (cmods_source);
                    
                gboolean aggregate = TRUE;
                size_t sizeof_dup = mono_sizeof_type_with_mods (total_cmods, aggregate);

                /* FIXME: if image, and the images of the custom modifiers from
                 * o and cmods_source are all different, we need an image
                 * set... */
                MonoType *r = image ? (MonoType *)mono_image_alloc0 (image, sizeof_dup) : (MonoType*)g_malloc0 (sizeof_dup);

                mono_type_with_mods_init (r, total_cmods, aggregate);

                memcpy (r, o, mono_sizeof_type_with_mods (0, FALSE));
                deep_type_dup_fixup (image, r, o);

                /* Try not to blow up the stack. See comment on
                 * MONO_MAX_EXPECTED_CMODS.  Since here we're appending all the
                 * mods together, it's possible we'll end up with more than the
                 * maximum allowed.  If that ever happens in practice, we
                 * should redefine the bound and possibly make this function
                 * fail dynamically instead of asserting.
                 */
                g_assert (total_cmods < MONO_MAX_EXPECTED_CMODS);
                size_t r_container_size = mono_sizeof_aggregate_modifiers (total_cmods);
                MonoAggregateModContainer *r_container_candidate = g_alloca (r_container_size);
                memset (r_container_candidate, 0, r_container_size);
                uint8_t dest_offset = 0;

                dest_offset = custom_modifier_copy (r_container_candidate, dest_offset, o);
                dest_offset = custom_modifier_copy (r_container_candidate, dest_offset, cmods_source);
                g_assert (dest_offset == total_cmods);
                r_container_candidate->count = total_cmods;

                mono_type_set_amods (r, mono_metadata_get_canonical_aggregate_modifiers (r_container_candidate));

                return r;
        }
}

/**
 * Works the same way as mono_metadata_type_dup but pick cmods from @cmods_source
 */
MonoType *
mono_metadata_type_dup_with_cmods (MonoImage *image, const MonoType *o, const MonoType *cmods_source)
{
        if (o->has_cmods && o != cmods_source && cmods_source->has_cmods) {
                return do_metadata_type_dup_append_cmods (image, o, cmods_source);
        }

        MonoType *r = NULL;

        /* if we get here, either o and cmods_source alias, or else exactly one of them has cmods. */

        uint8_t num_mods = MAX (mono_type_custom_modifier_count (o), mono_type_custom_modifier_count (cmods_source));
        gboolean aggregate = mono_type_is_aggregate_mods (o) || mono_type_is_aggregate_mods (cmods_source);
        size_t sizeof_r = mono_sizeof_type_with_mods (num_mods, aggregate);

        r = image ? (MonoType *)mono_image_alloc0 (image, sizeof_r) : (MonoType *)g_malloc0 (sizeof_r);

        if (cmods_source->has_cmods) {
                /* FIXME: if it's aggregate what do we assert here? */
                g_assert (!image || (!aggregate && image == mono_type_get_cmods (cmods_source)->image));
                memcpy (r, cmods_source, mono_sizeof_type (cmods_source));
        }

        memcpy (r, o, mono_sizeof_type (o));

        /* reset custom mod count and aggregateness to be correct. */
        mono_type_with_mods_init (r, num_mods, aggregate);
        if (aggregate)
                mono_type_set_amods (r, mono_type_is_aggregate_mods (o) ? mono_type_get_amods (o) : mono_type_get_amods (cmods_source));
        deep_type_dup_fixup (image, r, o);
        return r;
}


static void
deep_type_dup_fixup (MonoImage *image, MonoType *r, const MonoType *o)
{
        if (o->type == MONO_TYPE_PTR) {
                r->data.type = mono_metadata_type_dup (image, o->data.type);
        } else if (o->type == MONO_TYPE_ARRAY) {
                r->data.array = mono_dup_array_type (image, o->data.array);
        } else if (o->type == MONO_TYPE_FNPTR) {
                /*FIXME the dup'ed signature is leaked mono_metadata_free_type*/
                r->data.method = mono_metadata_signature_deep_dup (image, o->data.method);
        }
}

/**
 * mono_signature_hash:
 */
guint
mono_signature_hash (MonoMethodSignature *sig)
{
        guint i, res = sig->ret->type;

        for (i = 0; i < sig->param_count; i++)
                res = (res << 5) - res + mono_type_hash (sig->params[i]);

        return res;
}

/*
 * mono_metadata_encode_value:
 * @value: value to encode
 * @buf: buffer where to write the compressed representation
 * @endbuf: pointer updated to point at the end of the encoded output
 *
 * Encodes the value @value in the compressed representation used
 * in metadata and stores the result in @buf. @buf needs to be big
 * enough to hold the data (4 bytes).
 */
void
mono_metadata_encode_value (guint32 value, char *buf, char **endbuf)
{
        char *p = buf;
        
        if (value < 0x80)
                *p++ = value;
        else if (value < 0x4000) {
                p [0] = 0x80 | (value >> 8);
                p [1] = value & 0xff;
                p += 2;
        } else {
                p [0] = (value >> 24) | 0xc0;
                p [1] = (value >> 16) & 0xff;
                p [2] = (value >> 8) & 0xff;
                p [3] = value & 0xff;
                p += 4;
        }
        if (endbuf)
                *endbuf = p;
}

/**
 * mono_metadata_field_info:
 * \param meta the Image the field is defined in
 * \param index the index in the field table representing the field
 * \param offset a pointer to an integer where to store the offset that  may have been specified for the field in a FieldLayout table
 * \param rva a pointer to the RVA of the field data in the image that may have been defined in a \c FieldRVA table
 * \param marshal_spec a pointer to the marshal spec that may have been defined for the field in a \c FieldMarshal table.
 *
 * Gather info for field \p index that may have been defined in the \c FieldLayout, 
 * \c FieldRVA and \c FieldMarshal tables.
 * Either of \p offset, \p rva and \p marshal_spec can be NULL if you're not interested 
 * in the data.
 */
void
mono_metadata_field_info (MonoImage *meta, guint32 index, guint32 *offset, guint32 *rva, 
                          MonoMarshalSpec **marshal_spec)
{
        mono_metadata_field_info_full (meta, index, offset, rva, marshal_spec, FALSE);
}

void
mono_metadata_field_info_with_mempool (MonoImage *meta, guint32 index, guint32 *offset, guint32 *rva, 
                          MonoMarshalSpec **marshal_spec)
{
        mono_metadata_field_info_full (meta, index, offset, rva, marshal_spec, TRUE);
}

static void
mono_metadata_field_info_full (MonoImage *meta, guint32 index, guint32 *offset, guint32 *rva, 
                                       MonoMarshalSpec **marshal_spec, gboolean alloc_from_image)
{
        MonoTableInfo *tdef;
        locator_t loc;

        loc.idx = index + 1;
        if (meta->uncompressed_metadata)
                loc.idx = search_ptr_table (meta, MONO_TABLE_FIELD_POINTER, loc.idx);

        if (offset) {
                tdef = &meta->tables [MONO_TABLE_FIELDLAYOUT];

                loc.col_idx = MONO_FIELD_LAYOUT_FIELD;
                loc.t = tdef;

                if (tdef->base && mono_binary_search (&loc, tdef->base, tdef->rows, tdef->row_size, table_locator)) {
                        *offset = mono_metadata_decode_row_col (tdef, loc.result, MONO_FIELD_LAYOUT_OFFSET);
                } else {
                        *offset = (guint32)-1;
                }
        }
        if (rva) {
                tdef = &meta->tables [MONO_TABLE_FIELDRVA];

                loc.col_idx = MONO_FIELD_RVA_FIELD;
                loc.t = tdef;
                
                if (tdef->base && mono_binary_search (&loc, tdef->base, tdef->rows, tdef->row_size, table_locator)) {
                        /*
                         * LAMESPEC: There is no signature, no nothing, just the raw data.
                         */
                        *rva = mono_metadata_decode_row_col (tdef, loc.result, MONO_FIELD_RVA_RVA);
                } else {
                        *rva = 0;
                }
        }
        if (marshal_spec) {
                const char *p;
                
                if ((p = mono_metadata_get_marshal_info (meta, index, TRUE))) {
                        *marshal_spec = mono_metadata_parse_marshal_spec_full (alloc_from_image ? meta : NULL, meta, p);
                }
        }

}

/**
 * mono_metadata_get_constant_index:
 * \param meta the Image the field is defined in
 * \param index the token that may have a row defined in the constants table
 * \param hint possible position for the row
 *
 * \p token must be a \c FieldDef, \c ParamDef or \c PropertyDef token.
 *
 * \returns the index into the \c Constants table or 0 if not found.
 */
guint32
mono_metadata_get_constant_index (MonoImage *meta, guint32 token, guint32 hint)
{
        MonoTableInfo *tdef;
        locator_t loc;
        guint32 index = mono_metadata_token_index (token);

        tdef = &meta->tables [MONO_TABLE_CONSTANT];
        index <<= MONO_HASCONSTANT_BITS;
        switch (mono_metadata_token_table (token)) {
        case MONO_TABLE_FIELD:
                index |= MONO_HASCONSTANT_FIEDDEF;
                break;
        case MONO_TABLE_PARAM:
                index |= MONO_HASCONSTANT_PARAM;
                break;
        case MONO_TABLE_PROPERTY:
                index |= MONO_HASCONSTANT_PROPERTY;
                break;
        default:
                g_warning ("Not a valid token for the constant table: 0x%08x", token);
                return 0;
        }
        loc.idx = index;
        loc.col_idx = MONO_CONSTANT_PARENT;
        loc.t = tdef;

        /* FIXME: Index translation */

        if ((hint > 0) && (hint < tdef->rows) && (mono_metadata_decode_row_col (tdef, hint - 1, MONO_CONSTANT_PARENT) == index))
                return hint;

        if (tdef->base && mono_binary_search (&loc, tdef->base, tdef->rows, tdef->row_size, table_locator)) {
                return loc.result + 1;
        }
        return 0;
}

/**
 * mono_metadata_events_from_typedef:
 * \param meta metadata context
 * \param index 0-based index (in the \c TypeDef table) describing a type
 * \returns the 0-based index in the \c Event table for the events in the
 * type. The last event that belongs to the type (plus 1) is stored
 * in the \p end_idx pointer.
 */
guint32
mono_metadata_events_from_typedef (MonoImage *meta, guint32 index, guint *end_idx)
{
        locator_t loc;
        guint32 start, end;
        MonoTableInfo *tdef  = &meta->tables [MONO_TABLE_EVENTMAP];

        *end_idx = 0;
        
        if (!tdef->base)
                return 0;

        loc.t = tdef;
        loc.col_idx = MONO_EVENT_MAP_PARENT;
        loc.idx = index + 1;

        if (!mono_binary_search (&loc, tdef->base, tdef->rows, tdef->row_size, table_locator))
                return 0;
        
        start = mono_metadata_decode_row_col (tdef, loc.result, MONO_EVENT_MAP_EVENTLIST);
        if (loc.result + 1 < tdef->rows) {
                end = mono_metadata_decode_row_col (tdef, loc.result + 1, MONO_EVENT_MAP_EVENTLIST) - 1;
        } else {
                end = meta->tables [MONO_TABLE_EVENT].rows;
        }

        *end_idx = end;
        return start - 1;
}

/**
 * mono_metadata_methods_from_event:
 * \param meta metadata context
 * \param index 0-based index (in the \c Event table) describing a event
 * \returns the 0-based index in the \c MethodDef table for the methods in the
 * event. The last method that belongs to the event (plus 1) is stored
 * in the \p end_idx pointer.
 */
guint32
mono_metadata_methods_from_event   (MonoImage *meta, guint32 index, guint *end_idx)
{
        locator_t loc;
        guint start, end;
        guint32 cols [MONO_METHOD_SEMA_SIZE];
        MonoTableInfo *msemt = &meta->tables [MONO_TABLE_METHODSEMANTICS];

        *end_idx = 0;
        if (!msemt->base)
                return 0;

        if (meta->uncompressed_metadata)
            index = search_ptr_table (meta, MONO_TABLE_EVENT_POINTER, index + 1) - 1;

        loc.t = msemt;
        loc.col_idx = MONO_METHOD_SEMA_ASSOCIATION;
        loc.idx = ((index + 1) << MONO_HAS_SEMANTICS_BITS) | MONO_HAS_SEMANTICS_EVENT; /* Method association coded index */

        if (!mono_binary_search (&loc, msemt->base, msemt->rows, msemt->row_size, table_locator))
                return 0;

        start = loc.result;
        /*
         * We may end up in the middle of the rows... 
         */
        while (start > 0) {
                if (loc.idx == mono_metadata_decode_row_col (msemt, start - 1, MONO_METHOD_SEMA_ASSOCIATION))
                        start--;
                else
                        break;
        }
        end = start + 1;
        while (end < msemt->rows) {
                mono_metadata_decode_row (msemt, end, cols, MONO_METHOD_SEMA_SIZE);
                if (cols [MONO_METHOD_SEMA_ASSOCIATION] != loc.idx)
                        break;
                ++end;
        }
        *end_idx = end;
        return start;
}

/**
 * mono_metadata_properties_from_typedef:
 * \param meta metadata context
 * \param index 0-based index (in the \c TypeDef table) describing a type
 * \returns the 0-based index in the \c Property table for the properties in the
 * type. The last property that belongs to the type (plus 1) is stored
 * in the \p end_idx pointer.
 */
guint32
mono_metadata_properties_from_typedef (MonoImage *meta, guint32 index, guint *end_idx)
{
        locator_t loc;
        guint32 start, end;
        MonoTableInfo *tdef  = &meta->tables [MONO_TABLE_PROPERTYMAP];

        *end_idx = 0;
        
        if (!tdef->base)
                return 0;

        loc.t = tdef;
        loc.col_idx = MONO_PROPERTY_MAP_PARENT;
        loc.idx = index + 1;

        if (!mono_binary_search (&loc, tdef->base, tdef->rows, tdef->row_size, table_locator))
                return 0;
        
        start = mono_metadata_decode_row_col (tdef, loc.result, MONO_PROPERTY_MAP_PROPERTY_LIST);
        if (loc.result + 1 < tdef->rows) {
                end = mono_metadata_decode_row_col (tdef, loc.result + 1, MONO_PROPERTY_MAP_PROPERTY_LIST) - 1;
        } else {
                end = meta->tables [MONO_TABLE_PROPERTY].rows;
        }

        *end_idx = end;
        return start - 1;
}

/**
 * mono_metadata_methods_from_property:
 * \param meta metadata context
 * \param index 0-based index (in the \c PropertyDef table) describing a property
 * \returns the 0-based index in the \c MethodDef table for the methods in the
 * property. The last method that belongs to the property (plus 1) is stored
 * in the \p end_idx pointer.
 */
guint32
mono_metadata_methods_from_property   (MonoImage *meta, guint32 index, guint *end_idx)
{
        locator_t loc;
        guint start, end;
        guint32 cols [MONO_METHOD_SEMA_SIZE];
        MonoTableInfo *msemt = &meta->tables [MONO_TABLE_METHODSEMANTICS];

        *end_idx = 0;
        if (!msemt->base)
                return 0;

        if (meta->uncompressed_metadata)
            index = search_ptr_table (meta, MONO_TABLE_PROPERTY_POINTER, index + 1) - 1;

        loc.t = msemt;
        loc.col_idx = MONO_METHOD_SEMA_ASSOCIATION;
        loc.idx = ((index + 1) << MONO_HAS_SEMANTICS_BITS) | MONO_HAS_SEMANTICS_PROPERTY; /* Method association coded index */

        if (!mono_binary_search (&loc, msemt->base, msemt->rows, msemt->row_size, table_locator))
                return 0;

        start = loc.result;
        /*
         * We may end up in the middle of the rows... 
         */
        while (start > 0) {
                if (loc.idx == mono_metadata_decode_row_col (msemt, start - 1, MONO_METHOD_SEMA_ASSOCIATION))
                        start--;
                else
                        break;
        }
        end = start + 1;
        while (end < msemt->rows) {
                mono_metadata_decode_row (msemt, end, cols, MONO_METHOD_SEMA_SIZE);
                if (cols [MONO_METHOD_SEMA_ASSOCIATION] != loc.idx)
                        break;
                ++end;
        }
        *end_idx = end;
        return start;
}

/**
 * mono_metadata_implmap_from_method:
 */
guint32
mono_metadata_implmap_from_method (MonoImage *meta, guint32 method_idx)
{
        locator_t loc;
        MonoTableInfo *tdef  = &meta->tables [MONO_TABLE_IMPLMAP];

        if (!tdef->base)
                return 0;

        /* No index translation seems to be needed */

        loc.t = tdef;
        loc.col_idx = MONO_IMPLMAP_MEMBER;
        loc.idx = ((method_idx + 1) << MONO_MEMBERFORWD_BITS) | MONO_MEMBERFORWD_METHODDEF;

        if (!mono_binary_search (&loc, tdef->base, tdef->rows, tdef->row_size, table_locator))
                return 0;

        return loc.result + 1;
}

/**
 * mono_type_create_from_typespec:
 * \param image context where the image is created
 * \param type_spec  typespec token
 * \deprecated use \c mono_type_create_from_typespec_checked that has proper error handling
 *
 * Creates a \c MonoType representing the \c TypeSpec indexed by the \p type_spec
 * token.
 */
MonoType *
mono_type_create_from_typespec (MonoImage *image, guint32 type_spec)
{
        ERROR_DECL (error);
        MonoType *type = mono_type_create_from_typespec_checked (image, type_spec, error);
        if (!type)
                 g_error ("Could not create typespec %x due to %s", type_spec, mono_error_get_message (error));
        return type;
}

MonoType *
mono_type_create_from_typespec_checked (MonoImage *image, guint32 type_spec, MonoError *error)

{
        guint32 idx = mono_metadata_token_index (type_spec);
        MonoTableInfo *t;
        guint32 cols [MONO_TYPESPEC_SIZE];
        const char *ptr;
        MonoType *type, *type2;

        error_init (error);

        type = (MonoType *)mono_conc_hashtable_lookup (image->typespec_cache, GUINT_TO_POINTER (type_spec));
        if (type)
                return type;

        t = &image->tables [MONO_TABLE_TYPESPEC];

        mono_metadata_decode_row (t, idx-1, cols, MONO_TYPESPEC_SIZE);
        ptr = mono_metadata_blob_heap (image, cols [MONO_TYPESPEC_SIGNATURE]);

        if (!mono_verifier_verify_typespec_signature (image, cols [MONO_TYPESPEC_SIGNATURE], type_spec, error))
                return NULL;

        mono_metadata_decode_value (ptr, &ptr);

        type = mono_metadata_parse_type_checked (image, NULL, 0, TRUE, ptr, &ptr, error);
        if (!type)
                return NULL;

        type2 = mono_metadata_type_dup (image, type);
        mono_metadata_free_type (type);

        mono_image_lock (image);

        /* We might leak some data in the image mempool if found */
        type = (MonoType*)mono_conc_hashtable_insert (image->typespec_cache, GUINT_TO_POINTER (type_spec), type2);
        if (!type)
                type = type2;

        mono_image_unlock (image);

        return type;
}


static char*
mono_image_strndup (MonoImage *image, const char *data, guint len)
{
        char *res;
        if (!image)
                return g_strndup (data, len);
        res = (char *)mono_image_alloc (image, len + 1);
        memcpy (res, data, len);
        res [len] = 0;
        return res;
}

/**
 * mono_metadata_parse_marshal_spec:
 */
MonoMarshalSpec *
mono_metadata_parse_marshal_spec (MonoImage *image, const char *ptr)
{
        return mono_metadata_parse_marshal_spec_full (NULL, image, ptr);
}

/*
 * If IMAGE is non-null, memory will be allocated from its mempool, otherwise it will be allocated using malloc.
 * PARENT_IMAGE is the image containing the marshal spec.
 */
MonoMarshalSpec *
mono_metadata_parse_marshal_spec_full (MonoImage *image, MonoImage *parent_image, const char *ptr)
{
        MonoMarshalSpec *res;
        int len;
        const char *start = ptr;

        /* fixme: this is incomplete, but I cant find more infos in the specs */

        if (image)
                res = (MonoMarshalSpec *)mono_image_alloc0 (image, sizeof (MonoMarshalSpec));
        else
                res = g_new0 (MonoMarshalSpec, 1);
        
        len = mono_metadata_decode_value (ptr, &ptr);
        res->native = (MonoMarshalNative)*ptr++;

        if (res->native == MONO_NATIVE_LPARRAY) {
                res->data.array_data.param_num = -1;
                res->data.array_data.num_elem = -1;
                res->data.array_data.elem_mult = -1;

                if (ptr - start <= len)
                        res->data.array_data.elem_type = (MonoMarshalNative)*ptr++;
                if (ptr - start <= len)
                        res->data.array_data.param_num = mono_metadata_decode_value (ptr, &ptr);
                if (ptr - start <= len)
                        res->data.array_data.num_elem = mono_metadata_decode_value (ptr, &ptr);
                if (ptr - start <= len) {
                        /*
                         * LAMESPEC: Older spec versions say this parameter comes before 
                         * num_elem. Never spec versions don't talk about elem_mult at
                         * all, but csc still emits it, and it is used to distinguish
                         * between param_num being 0, and param_num being omitted.
                         * So if (param_num == 0) && (num_elem > 0), then
                         * elem_mult == 0 -> the array size is num_elem
                         * elem_mult == 1 -> the array size is @param_num + num_elem
                         */
                        res->data.array_data.elem_mult = mono_metadata_decode_value (ptr, &ptr);
                }
        } 

        if (res->native == MONO_NATIVE_BYVALTSTR) {
                if (ptr - start <= len)
                        res->data.array_data.num_elem = mono_metadata_decode_value (ptr, &ptr);
        }

        if (res->native == MONO_NATIVE_BYVALARRAY) {
                if (ptr - start <= len)
                        res->data.array_data.num_elem = mono_metadata_decode_value (ptr, &ptr);
        }
        
        if (res->native == MONO_NATIVE_CUSTOM) {
                /* skip unused type guid */
                len = mono_metadata_decode_value (ptr, &ptr);
                ptr += len;
                /* skip unused native type name */
                len = mono_metadata_decode_value (ptr, &ptr);
                ptr += len;
                /* read custom marshaler type name */
                len = mono_metadata_decode_value (ptr, &ptr);
                res->data.custom_data.custom_name = mono_image_strndup (image, ptr, len);               
                ptr += len;
                /* read cookie string */
                len = mono_metadata_decode_value (ptr, &ptr);
                res->data.custom_data.cookie = mono_image_strndup (image, ptr, len);
                res->data.custom_data.image = parent_image;
        }

        if (res->native == MONO_NATIVE_SAFEARRAY) {
                res->data.safearray_data.elem_type = (MonoMarshalVariant)0;
                res->data.safearray_data.num_elem = 0;
                if (ptr - start <= len)
                        res->data.safearray_data.elem_type = (MonoMarshalVariant)*ptr++;
                if (ptr - start <= len)
                        res->data.safearray_data.num_elem = *ptr++;
        }
        return res;
}

/**
 * mono_metadata_free_marshal_spec:
 */
void 
mono_metadata_free_marshal_spec (MonoMarshalSpec *spec)
{
        if (!spec)
                return;

        if (spec->native == MONO_NATIVE_CUSTOM) {
                g_free (spec->data.custom_data.custom_name);
                g_free (spec->data.custom_data.cookie);
        }
        g_free (spec);
}

/**
 * mono_type_to_unmanaged:
 * The value pointed to by \p conv will contain the kind of marshalling required for this
 * particular type one of the \c MONO_MARSHAL_CONV_ enumeration values.
 * \returns A \c MonoMarshalNative enumeration value (<code>MONO_NATIVE_</code>) value
 * describing the underlying native reprensetation of the type.
 */
guint32 // FIXMEcxx MonoMarshalNative
mono_type_to_unmanaged (MonoType *type, MonoMarshalSpec *mspec, gboolean as_field,
                        gboolean unicode, MonoMarshalConv *conv) 
{
        MonoMarshalConv dummy_conv;
        int t = type->type;

        if (!conv)
                conv = &dummy_conv;

        *conv = MONO_MARSHAL_CONV_NONE;

        if (type->byref)
                return MONO_NATIVE_UINT;

handle_enum:
        switch (t) {
        case MONO_TYPE_BOOLEAN: 
                if (mspec) {
                        switch (mspec->native) {
                        case MONO_NATIVE_VARIANTBOOL:
                                *conv = MONO_MARSHAL_CONV_BOOL_VARIANTBOOL;
                                return MONO_NATIVE_VARIANTBOOL;
                        case MONO_NATIVE_BOOLEAN:
                                *conv = MONO_MARSHAL_CONV_BOOL_I4;
                                return MONO_NATIVE_BOOLEAN;
                        case MONO_NATIVE_I1:
                        case MONO_NATIVE_U1:
                                return mspec->native;
                        default:
                                g_error ("cant marshal bool to native type %02x", mspec->native);
                        }
                }
                *conv = MONO_MARSHAL_CONV_BOOL_I4;
                return MONO_NATIVE_BOOLEAN;
        case MONO_TYPE_CHAR:
                if (mspec) {
                        switch (mspec->native) {
                        case MONO_NATIVE_U2:
                        case MONO_NATIVE_U1:
                                return mspec->native;
                        default:
                                g_error ("cant marshal char to native type %02x", mspec->native);
                        }
                }
                return unicode ? MONO_NATIVE_U2 : MONO_NATIVE_U1;
        case MONO_TYPE_I1: return MONO_NATIVE_I1;
        case MONO_TYPE_U1: return MONO_NATIVE_U1;
        case MONO_TYPE_I2: return MONO_NATIVE_I2;
        case MONO_TYPE_U2: return MONO_NATIVE_U2;
        case MONO_TYPE_I4: return MONO_NATIVE_I4;
        case MONO_TYPE_U4: return MONO_NATIVE_U4;
        case MONO_TYPE_I8: return MONO_NATIVE_I8;
        case MONO_TYPE_U8: return MONO_NATIVE_U8;
        case MONO_TYPE_R4: return MONO_NATIVE_R4;
        case MONO_TYPE_R8: return MONO_NATIVE_R8;
        case MONO_TYPE_STRING:
                if (mspec) {
                        switch (mspec->native) {
                        case MONO_NATIVE_BSTR:
                                *conv = MONO_MARSHAL_CONV_STR_BSTR;
                                return MONO_NATIVE_BSTR;
                        case MONO_NATIVE_LPSTR:
                                *conv = MONO_MARSHAL_CONV_STR_LPSTR;
                                return MONO_NATIVE_LPSTR;
                        case MONO_NATIVE_LPWSTR:
                                *conv = MONO_MARSHAL_CONV_STR_LPWSTR;
                                return MONO_NATIVE_LPWSTR;
                        case MONO_NATIVE_LPTSTR:
                                *conv = MONO_MARSHAL_CONV_STR_LPTSTR;
                                return MONO_NATIVE_LPTSTR;
                        case MONO_NATIVE_ANSIBSTR:
                                *conv = MONO_MARSHAL_CONV_STR_ANSIBSTR;
                                return MONO_NATIVE_ANSIBSTR;
                        case MONO_NATIVE_TBSTR:
                                *conv = MONO_MARSHAL_CONV_STR_TBSTR;
                                return MONO_NATIVE_TBSTR;
                        case MONO_NATIVE_UTF8STR:
                                *conv = MONO_MARSHAL_CONV_STR_UTF8STR;
                                return MONO_NATIVE_UTF8STR;
                        case MONO_NATIVE_BYVALTSTR:
                                if (unicode)
                                        *conv = MONO_MARSHAL_CONV_STR_BYVALWSTR;
                                else
                                        *conv = MONO_MARSHAL_CONV_STR_BYVALSTR;
                                return MONO_NATIVE_BYVALTSTR;
                        default:
                                g_error ("Can not marshal string to native type '%02x': Invalid managed/unmanaged type combination (String fields must be paired with LPStr, LPWStr, BStr or ByValTStr).", mspec->native);
                        }
                }       
                if (unicode) {
                        *conv = MONO_MARSHAL_CONV_STR_LPWSTR;
                        return MONO_NATIVE_LPWSTR; 
                }
                else {
                        *conv = MONO_MARSHAL_CONV_STR_LPSTR;
                        return MONO_NATIVE_LPSTR; 
                }
        case MONO_TYPE_PTR: return MONO_NATIVE_UINT;
        case MONO_TYPE_VALUETYPE: /*FIXME*/
                if (m_class_is_enumtype (type->data.klass)) {
                        t = mono_class_enum_basetype_internal (type->data.klass)->type;
                        goto handle_enum;
                }
                if (type->data.klass == mono_class_try_get_handleref_class ()){
                        *conv = MONO_MARSHAL_CONV_HANDLEREF;
                        return MONO_NATIVE_INT;
                }
                return MONO_NATIVE_STRUCT;
        case MONO_TYPE_SZARRAY: 
        case MONO_TYPE_ARRAY: 
                if (mspec) {
                        switch (mspec->native) {
                        case MONO_NATIVE_BYVALARRAY:
                                if ((m_class_get_element_class (type->data.klass) == mono_defaults.char_class) && !unicode)
                                        *conv = MONO_MARSHAL_CONV_ARRAY_BYVALCHARARRAY;
                                else
                                        *conv = MONO_MARSHAL_CONV_ARRAY_BYVALARRAY;
                                return MONO_NATIVE_BYVALARRAY;
                        case MONO_NATIVE_SAFEARRAY:
                                *conv = MONO_MARSHAL_CONV_ARRAY_SAVEARRAY;
                                return MONO_NATIVE_SAFEARRAY;
                        case MONO_NATIVE_LPARRAY:                               
                                *conv = MONO_MARSHAL_CONV_ARRAY_LPARRAY;
                                return MONO_NATIVE_LPARRAY;
                        default:
                                g_error ("cant marshal array as native type %02x", mspec->native);
                        }
                }       

                *conv = MONO_MARSHAL_CONV_ARRAY_LPARRAY;
                return MONO_NATIVE_LPARRAY;
        case MONO_TYPE_I: return MONO_NATIVE_INT;
        case MONO_TYPE_U: return MONO_NATIVE_UINT;
        case MONO_TYPE_CLASS: 
        case MONO_TYPE_OBJECT: {
                /* FIXME : we need to handle ArrayList and StringBuilder here, probably */
                if (mspec) {
                        switch (mspec->native) {
                        case MONO_NATIVE_STRUCT:
                                // [MarshalAs(UnmanagedType.Struct)]
                                // object field;
                                //
                                // becomes a VARIANT
                                //
                                // [MarshalAs(UnmangedType.Struct)]
                                // SomeClass field;
                                //
                                // becomes uses the CONV_OBJECT_STRUCT conversion
                                if (t != MONO_TYPE_OBJECT)
                                        *conv = MONO_MARSHAL_CONV_OBJECT_STRUCT;
                                return MONO_NATIVE_STRUCT;
                        case MONO_NATIVE_CUSTOM:
                                return MONO_NATIVE_CUSTOM;
                        case MONO_NATIVE_INTERFACE:
                                *conv = MONO_MARSHAL_CONV_OBJECT_INTERFACE;
                                return MONO_NATIVE_INTERFACE;
                        case MONO_NATIVE_IDISPATCH:
                                *conv = MONO_MARSHAL_CONV_OBJECT_IDISPATCH;
                                return MONO_NATIVE_IDISPATCH;
                        case MONO_NATIVE_IUNKNOWN:
                                *conv = MONO_MARSHAL_CONV_OBJECT_IUNKNOWN;
                                return MONO_NATIVE_IUNKNOWN;
                        case MONO_NATIVE_FUNC:
                                if (t == MONO_TYPE_CLASS && (type->data.klass == mono_defaults.multicastdelegate_class ||
                                                                                         type->data.klass == mono_defaults.delegate_class || 
                                                                                        m_class_get_parent (type->data.klass) == mono_defaults.multicastdelegate_class)) {
                                        *conv = MONO_MARSHAL_CONV_DEL_FTN;
                                        return MONO_NATIVE_FUNC;
                                }
                                /* Fall through */
                        default:
                                g_error ("cant marshal object as native type %02x", mspec->native);
                        }
                }
                if (t == MONO_TYPE_CLASS && (type->data.klass == mono_defaults.multicastdelegate_class ||
                                             type->data.klass == mono_defaults.delegate_class || 
                                             m_class_get_parent (type->data.klass) == mono_defaults.multicastdelegate_class)) {
                        *conv = MONO_MARSHAL_CONV_DEL_FTN;
                        return MONO_NATIVE_FUNC;
                }
                if (mono_class_try_get_safehandle_class () && type->data.klass != NULL &&
                        mono_class_is_subclass_of_internal (type->data.klass,  mono_class_try_get_safehandle_class (), FALSE)){
                        *conv = MONO_MARSHAL_CONV_SAFEHANDLE;
                        return MONO_NATIVE_INT;
                }
#ifndef DISABLE_COM
                if (t == MONO_TYPE_CLASS && mono_cominterop_is_interface (type->data.klass)){
                        *conv = MONO_MARSHAL_CONV_OBJECT_INTERFACE;
                        return MONO_NATIVE_INTERFACE;
                }
#endif
                *conv = MONO_MARSHAL_CONV_OBJECT_STRUCT;
                return MONO_NATIVE_STRUCT;
        }
        case MONO_TYPE_FNPTR: return MONO_NATIVE_FUNC;
        case MONO_TYPE_GENERICINST:
                type = m_class_get_byval_arg (type->data.generic_class->container_class);
                t = type->type;
                goto handle_enum;
        case MONO_TYPE_TYPEDBYREF:
        default:
                g_error ("type 0x%02x not handled in marshal", t);
        }
        return MONO_NATIVE_MAX;
}

/**
 * mono_metadata_get_marshal_info:
 */
const char*
mono_metadata_get_marshal_info (MonoImage *meta, guint32 idx, gboolean is_field)
{
        locator_t loc;
        MonoTableInfo *tdef  = &meta->tables [MONO_TABLE_FIELDMARSHAL];

        if (!tdef->base)
                return NULL;

        loc.t = tdef;
        loc.col_idx = MONO_FIELD_MARSHAL_PARENT;
        loc.idx = ((idx + 1) << MONO_HAS_FIELD_MARSHAL_BITS) | (is_field? MONO_HAS_FIELD_MARSHAL_FIELDSREF: MONO_HAS_FIELD_MARSHAL_PARAMDEF);

        /* FIXME: Index translation */

        if (!mono_binary_search (&loc, tdef->base, tdef->rows, tdef->row_size, table_locator))
                return NULL;

        return mono_metadata_blob_heap (meta, mono_metadata_decode_row_col (tdef, loc.result, MONO_FIELD_MARSHAL_NATIVE_TYPE));
}

MonoMethod*
mono_method_from_method_def_or_ref (MonoImage *m, guint32 tok, MonoGenericContext *context, MonoError *error)
{
        MonoMethod *result = NULL;
        guint32 idx = tok >> MONO_METHODDEFORREF_BITS;

        error_init (error);

        switch (tok & MONO_METHODDEFORREF_MASK) {
        case MONO_METHODDEFORREF_METHODDEF:
                result = mono_get_method_checked (m, MONO_TOKEN_METHOD_DEF | idx, NULL, context, error);
                break;
        case MONO_METHODDEFORREF_METHODREF:
                result = mono_get_method_checked (m, MONO_TOKEN_MEMBER_REF | idx, NULL, context, error);
                break;
        default:
                mono_error_set_bad_image (error, m, "Invalid MethodDefOfRef token %x", tok);
        }

        return result;
}

/*
 * mono_class_get_overrides_full:
 *
 *  Compute the method overrides belonging to class @type_token in @overrides, and the number of overrides in @num_overrides.
 *
 */
void
mono_class_get_overrides_full (MonoImage *image, guint32 type_token, MonoMethod ***overrides, gint32 *num_overrides, MonoGenericContext *generic_context, MonoError *error)
{
        locator_t loc;
        MonoTableInfo *tdef  = &image->tables [MONO_TABLE_METHODIMPL];
        guint32 start, end;
        gint32 i, num;
        guint32 cols [MONO_METHODIMPL_SIZE];
        MonoMethod **result;
        
        error_init (error);

        *overrides = NULL;
        if (num_overrides)
                *num_overrides = 0;

        if (!tdef->base)
                return;

        loc.t = tdef;
        loc.col_idx = MONO_METHODIMPL_CLASS;
        loc.idx = mono_metadata_token_index (type_token);

        if (!mono_binary_search (&loc, tdef->base, tdef->rows, tdef->row_size, table_locator))
                return;

        start = loc.result;
        end = start + 1;
        /*
         * We may end up in the middle of the rows... 
         */
        while (start > 0) {
                if (loc.idx == mono_metadata_decode_row_col (tdef, start - 1, MONO_METHODIMPL_CLASS))
                        start--;
                else
                        break;
        }
        while (end < tdef->rows) {
                if (loc.idx == mono_metadata_decode_row_col (tdef, end, MONO_METHODIMPL_CLASS))
                        end++;
                else
                        break;
        }
        num = end - start;
        result = g_new (MonoMethod*, num * 2);
        for (i = 0; i < num; ++i) {
                MonoMethod *method;

                if (!mono_verifier_verify_methodimpl_row (image, start + i, error))
                        break;

                mono_metadata_decode_row (tdef, start + i, cols, MONO_METHODIMPL_SIZE);
                method = mono_method_from_method_def_or_ref (image, cols [MONO_METHODIMPL_DECLARATION], generic_context, error);
                if (!method)
                        break;

                result [i * 2] = method;
                method = mono_method_from_method_def_or_ref (image, cols [MONO_METHODIMPL_BODY], generic_context, error);
                if (!method)
                        break;

                result [i * 2 + 1] = method;
        }

        if (!is_ok (error)) {
                g_free (result);
                *overrides = NULL;
                if (num_overrides)
                        *num_overrides = 0;
        } else {
                *overrides = result;
                if (num_overrides)
                        *num_overrides = num;
        }
}

/**
 * mono_guid_to_string:
 *
 * Converts a 16 byte Microsoft GUID to the standard string representation.
 */
char *
mono_guid_to_string (const guint8 *guid)
{
        return g_strdup_printf ("%02X%02X%02X%02X-%02X%02X-%02X%02X-%02X%02X-%02X%02X%02X%02X%02X%02X", 
                                guid[3], guid[2], guid[1], guid[0],
                                guid[5], guid[4],
                                guid[7], guid[6],
                                guid[8], guid[9],
                                guid[10], guid[11], guid[12], guid[13], guid[14], guid[15]);
}

/**
 * mono_guid_to_string_minimal:
 *
 * Converts a 16 byte Microsoft GUID to lower case no '-' representation..
 */
char *
mono_guid_to_string_minimal (const guint8 *guid)
{
        return g_strdup_printf ("%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x",
                                guid[3], guid[2], guid[1], guid[0],
                                guid[5], guid[4],
                                guid[7], guid[6],
                                guid[8], guid[9],
                                guid[10], guid[11], guid[12], guid[13], guid[14], guid[15]);
}
static gboolean
get_constraints (MonoImage *image, int owner, MonoClass ***constraints, MonoGenericContainer *container, MonoError *error)
{
        MonoTableInfo *tdef  = &image->tables [MONO_TABLE_GENERICPARAMCONSTRAINT];
        guint32 cols [MONO_GENPARCONSTRAINT_SIZE];
        guint32 i, token, found;
        MonoClass *klass, **res;
        GSList *cons = NULL, *tmp;
        MonoGenericContext *context = &container->context;

        error_init (error);

        *constraints = NULL;
        found = 0;
        for (i = 0; i < tdef->rows; ++i) {
                mono_metadata_decode_row (tdef, i, cols, MONO_GENPARCONSTRAINT_SIZE);
                if (cols [MONO_GENPARCONSTRAINT_GENERICPAR] == owner) {
                        token = mono_metadata_token_from_dor (cols [MONO_GENPARCONSTRAINT_CONSTRAINT]);
                        klass = mono_class_get_and_inflate_typespec_checked (image, token, context, error);
                        if (!klass) {
                                g_slist_free (cons);
                                return FALSE;
                        }
                        cons = g_slist_append (cons, klass);
                        ++found;
                } else {
                        /* contiguous list finished */
                        if (found)
                                break;
                }
        }
        if (!found)
                return TRUE;
        res = (MonoClass **)mono_image_alloc0 (image, sizeof (MonoClass*) * (found + 1));
        for (i = 0, tmp = cons; i < found; ++i, tmp = tmp->next) {
                res [i] = (MonoClass *)tmp->data;
        }
        g_slist_free (cons);
        *constraints = res;
        return TRUE;
}

/*
 * mono_metadata_get_generic_param_row:
 *
 * @image:
 * @token: TypeOrMethodDef token, owner for GenericParam
 * @owner: coded token, set on return
 * 
 * Returns: 1-based row-id in the GenericParam table whose
 * owner is @token. 0 if not found.
 */
guint32
mono_metadata_get_generic_param_row (MonoImage *image, guint32 token, guint32 *owner)
{
        MonoTableInfo *tdef  = &image->tables [MONO_TABLE_GENERICPARAM];
        locator_t loc;

        g_assert (owner);
        if (!tdef->base)
                return 0;

        if (mono_metadata_token_table (token) == MONO_TABLE_TYPEDEF)
                *owner = MONO_TYPEORMETHOD_TYPE;
        else if (mono_metadata_token_table (token) == MONO_TABLE_METHOD)
                *owner = MONO_TYPEORMETHOD_METHOD;
        else {
                g_error ("wrong token %x to get_generic_param_row", token);
                return 0;
        }
        *owner |= mono_metadata_token_index (token) << MONO_TYPEORMETHOD_BITS;

        loc.idx = *owner;
        loc.col_idx = MONO_GENERICPARAM_OWNER;
        loc.t = tdef;

        if (!mono_binary_search (&loc, tdef->base, tdef->rows, tdef->row_size, table_locator))
                return 0;

        /* Find the first entry by searching backwards */
        while ((loc.result > 0) && (mono_metadata_decode_row_col (tdef, loc.result - 1, MONO_GENERICPARAM_OWNER) == loc.idx))
                loc.result --;

        return loc.result + 1;
}

gboolean
mono_metadata_has_generic_params (MonoImage *image, guint32 token)
{
        guint32 owner;
        return mono_metadata_get_generic_param_row (image, token, &owner);
}

/*
 * Memory is allocated from IMAGE's mempool.
 */
gboolean
mono_metadata_load_generic_param_constraints_checked (MonoImage *image, guint32 token,
                                              MonoGenericContainer *container, MonoError *error)
{

        guint32 start_row, i, owner;
        error_init (error);

        if (! (start_row = mono_metadata_get_generic_param_row (image, token, &owner)))
                return TRUE;
        for (i = 0; i < container->type_argc; i++) {
                if (!get_constraints (image, start_row + i, &mono_generic_container_get_param_info (container, i)->constraints, container, error)) {
                        return FALSE;
                }
        }
        return TRUE;
}

/*
 * mono_metadata_load_generic_params:
 *
 * Load the type parameters from the type or method definition @token.
 *
 * Use this method after parsing a type or method definition to figure out whether it's a generic
 * type / method.  When parsing a method definition, @parent_container points to the generic container
 * of the current class, if any.
 *
 * Note: This method does not load the constraints: for typedefs, this has to be done after fully
 *       creating the type.
 *
 * Returns: NULL if @token is not a generic type or method definition or the new generic container.
 *
 * LOCKING: Acquires the loader lock
 *
 */
MonoGenericContainer *
mono_metadata_load_generic_params (MonoImage *image, guint32 token, MonoGenericContainer *parent_container, gpointer real_owner)
{
        MonoTableInfo *tdef  = &image->tables [MONO_TABLE_GENERICPARAM];
        guint32 cols [MONO_GENERICPARAM_SIZE];
        guint32 i, owner = 0, n;
        MonoGenericContainer *container;
        MonoGenericParamFull *params;
        MonoGenericContext *context;
        gboolean is_method = mono_metadata_token_table (token) == MONO_TABLE_METHOD;
        gboolean is_anonymous = real_owner == NULL;

        if (!(i = mono_metadata_get_generic_param_row (image, token, &owner)))
                return NULL;
        mono_metadata_decode_row (tdef, i - 1, cols, MONO_GENERICPARAM_SIZE);
        params = NULL;
        n = 0;
        container = (MonoGenericContainer *)mono_image_alloc0 (image, sizeof (MonoGenericContainer));
        container->is_anonymous = is_anonymous;
        if (is_anonymous) {
                container->owner.image = image;
        } else {
                if (is_method)
                        container->owner.method = (MonoMethod*)real_owner;
                else
                        container->owner.klass = (MonoClass*)real_owner;
        }
        do {
                n++;
                params = (MonoGenericParamFull *)g_realloc (params, sizeof (MonoGenericParamFull) * n);
                memset (&params [n - 1], 0, sizeof (MonoGenericParamFull));
                params [n - 1].owner = container;
                params [n - 1].num = cols [MONO_GENERICPARAM_NUMBER];
                params [n - 1].info.token = i | MONO_TOKEN_GENERIC_PARAM;
                params [n - 1].info.flags = cols [MONO_GENERICPARAM_FLAGS];
                params [n - 1].info.name = mono_metadata_string_heap (image, cols [MONO_GENERICPARAM_NAME]);
                if (params [n - 1].num != n - 1)
                        g_warning ("GenericParam table unsorted or hole in generic param sequence: token %d", i);
                if (++i > tdef->rows)
                        break;
                mono_metadata_decode_row (tdef, i - 1, cols, MONO_GENERICPARAM_SIZE);
        } while (cols [MONO_GENERICPARAM_OWNER] == owner);

        container->type_argc = n;
        container->type_params = (MonoGenericParamFull *)mono_image_alloc0 (image, sizeof (MonoGenericParamFull) * n);
        memcpy (container->type_params, params, sizeof (MonoGenericParamFull) * n);
        g_free (params);
        container->parent = parent_container;

        if (is_method)
                container->is_method = 1;

        g_assert (container->parent == NULL || container->is_method);

        context = &container->context;
        if (container->is_method) {
                context->class_inst = container->parent ? container->parent->context.class_inst : NULL;
                context->method_inst = mono_get_shared_generic_inst (container);
        } else {
                context->class_inst = mono_get_shared_generic_inst (container);
        }

        return container;
}

MonoGenericInst *
mono_get_shared_generic_inst (MonoGenericContainer *container)
{
        MonoType **type_argv;
        MonoType *helper;
        MonoGenericInst *nginst;
        int i;

        type_argv = g_new0 (MonoType *, container->type_argc);
        helper = g_new0 (MonoType, container->type_argc);

        for (i = 0; i < container->type_argc; i++) {
                MonoType *t = &helper [i];

                t->type = container->is_method ? MONO_TYPE_MVAR : MONO_TYPE_VAR;
                t->data.generic_param = mono_generic_container_get_param (container, i);

                type_argv [i] = t;
        }

        nginst = mono_metadata_get_generic_inst (container->type_argc, type_argv);

        g_free (type_argv);
        g_free (helper);

        return nginst;
}

/**
 * mono_type_is_byref:
 * \param type the \c MonoType operated on
 * \returns TRUE if \p type represents a type passed by reference,
 * FALSE otherwise.
 */
mono_bool
mono_type_is_byref (MonoType *type)
{
        mono_bool result;
        MONO_ENTER_GC_UNSAFE; // FIXME slow
        result = mono_type_is_byref_internal (type);
        MONO_EXIT_GC_UNSAFE;
        return result;
}

/**
 * mono_type_get_type:
 * \param type the \c MonoType operated on
 * \returns the IL type value for \p type. This is one of the \c MonoTypeEnum
 * enum members like \c MONO_TYPE_I4 or \c MONO_TYPE_STRING.
 */
int
mono_type_get_type (MonoType *type)
{
        return mono_type_get_type_internal (type);
}

/**
 * mono_type_get_signature:
 * \param type the \c MonoType operated on
 * It is only valid to call this function if \p type is a \c MONO_TYPE_FNPTR .
 * \returns the \c MonoMethodSignature pointer that describes the signature
 * of the function pointer \p type represents.
 */
MonoMethodSignature*
mono_type_get_signature (MonoType *type)
{
        return mono_type_get_signature_internal (type);
}

/**
 * mono_type_get_class:
 * \param type the \c MonoType operated on
 * It is only valid to call this function if \p type is a \c MONO_TYPE_CLASS or a
 * \c MONO_TYPE_VALUETYPE . For more general functionality, use \c mono_class_from_mono_type_internal,
 * instead.
 * \returns the \c MonoClass pointer that describes the class that \p type represents.
 */
MonoClass*
mono_type_get_class (MonoType *type)
{
        /* FIXME: review the runtime users before adding the assert here */
        return mono_type_get_class_internal (type);
}

/**
 * mono_type_get_array_type:
 * \param type the \c MonoType operated on
 * It is only valid to call this function if \p type is a \c MONO_TYPE_ARRAY .
 * \returns a \c MonoArrayType struct describing the array type that \p type
 * represents. The info includes details such as rank, array element type
 * and the sizes and bounds of multidimensional arrays.
 */
MonoArrayType*
mono_type_get_array_type (MonoType *type)
{
        return mono_type_get_array_type_internal (type);
}

/**
 * mono_type_get_ptr_type:
 * \pararm type the \c MonoType operated on
 * It is only valid to call this function if \p type is a \c MONO_TYPE_PTR .
 * \returns the \c MonoType pointer that describes the type that \p type
 * represents a pointer to.
 */
MonoType*
mono_type_get_ptr_type (MonoType *type)
{
        g_assert (type->type == MONO_TYPE_PTR);
        return type->data.type;
}

/**
 * mono_type_get_modifiers:
 */
MonoClass*
mono_type_get_modifiers (MonoType *type, gboolean *is_required, gpointer *iter)
{
        /* FIXME: implement */
        return NULL;
}

/**
 * mono_type_is_struct:
 * \param type the \c MonoType operated on
 * \returns TRUE if \p type is a struct, that is a \c ValueType but not an enum
 * or a basic type like \c System.Int32 . FALSE otherwise.
 */
mono_bool
mono_type_is_struct (MonoType *type)
{
        return (!type->byref && ((type->type == MONO_TYPE_VALUETYPE &&
                !m_class_is_enumtype (type->data.klass)) || (type->type == MONO_TYPE_TYPEDBYREF) ||
                ((type->type == MONO_TYPE_GENERICINST) && 
                mono_metadata_generic_class_is_valuetype (type->data.generic_class) &&
                !m_class_is_enumtype (type->data.generic_class->container_class))));
}

/**
 * mono_type_is_void:
 * \param type the \c MonoType operated on
 * \returns TRUE if \p type is \c System.Void . FALSE otherwise.
 */
mono_bool
mono_type_is_void (MonoType *type)
{
        return (type && (type->type == MONO_TYPE_VOID) && !type->byref);
}

/**
 * mono_type_is_pointer:
 * \param type the \c MonoType operated on
 * \returns TRUE if \p type is a managed or unmanaged pointer type. FALSE otherwise.
 */
mono_bool
mono_type_is_pointer (MonoType *type)
{
        return (type && ((type->byref || (type->type == MONO_TYPE_I) || type->type == MONO_TYPE_STRING)
                || (type->type == MONO_TYPE_SZARRAY) || (type->type == MONO_TYPE_CLASS) ||
                (type->type == MONO_TYPE_U) || (type->type == MONO_TYPE_OBJECT) ||
                (type->type == MONO_TYPE_ARRAY) || (type->type == MONO_TYPE_PTR) ||
                (type->type == MONO_TYPE_FNPTR)));
}

/**
 * mono_type_is_reference:
 * \param type the \c MonoType operated on
 * \returns TRUE if \p type represents an object reference. FALSE otherwise.
 */
mono_bool
mono_type_is_reference (MonoType *type)
{
        /* NOTE: changing this function to return TRUE more often may have
         * consequences for generic sharing in the AOT compiler.  In
         * particular, returning TRUE for generic parameters with a 'class'
         * constraint may cause crashes.
         */
        return (type && (((type->type == MONO_TYPE_STRING) ||
                (type->type == MONO_TYPE_SZARRAY) || (type->type == MONO_TYPE_CLASS) ||
                (type->type == MONO_TYPE_OBJECT) || (type->type == MONO_TYPE_ARRAY)) ||
                ((type->type == MONO_TYPE_GENERICINST) &&
                !mono_metadata_generic_class_is_valuetype (type->data.generic_class))));
}

mono_bool
mono_type_is_generic_parameter (MonoType *type)
{
        return !type->byref && (type->type == MONO_TYPE_VAR || type->type == MONO_TYPE_MVAR);
}

/**
 * mono_signature_get_return_type:
 * \param sig the method signature inspected
 * \returns the return type of the method signature \p sig
 */
MonoType*
mono_signature_get_return_type (MonoMethodSignature *sig)
{
        MonoType *result;
        MONO_ENTER_GC_UNSAFE;
        result = sig->ret;
        MONO_EXIT_GC_UNSAFE;
        return result;
}

/**
 * mono_signature_get_params:
 * \param sig the method signature inspected
 * \param iter pointer to an iterator
 * Iterates over the parameters for the method signature \p sig.
 * A \c void* pointer must be initialized to NULL to start the iteration
 * and its address is passed to this function repeteadly until it returns
 * NULL.
 * \returns the next parameter type of the method signature \p sig,
 * NULL when finished.
 */
MonoType*
mono_signature_get_params (MonoMethodSignature *sig, gpointer *iter)
{
        MonoType *result;
        MONO_ENTER_GC_UNSAFE;
        result = mono_signature_get_params_internal (sig, iter);
        MONO_EXIT_GC_UNSAFE;
        return result;
}

MonoType*
mono_signature_get_params_internal (MonoMethodSignature *sig, gpointer *iter)
{
        MonoType** type;
        if (!iter)
                return NULL;
        if (!*iter) {
                /* start from the first */
                if (sig->param_count) {
                        *iter = &sig->params [0];
                        return sig->params [0];
                } else {
                        /* no method */
                        return NULL;
                }
        }
        type = (MonoType **)*iter;
        type++;
        if (type < &sig->params [sig->param_count]) {
                *iter = type;
                return *type;
        }
        return NULL;
}

/**
 * mono_signature_get_param_count:
 * \param sig the method signature inspected
 * \returns the number of parameters in the method signature \p sig.
 */
guint32
mono_signature_get_param_count (MonoMethodSignature *sig)
{
        return sig->param_count;
}

/**
 * mono_signature_get_call_conv:
 * \param sig the method signature inspected
 * \returns the call convention of the method signature \p sig.
 */
guint32
mono_signature_get_call_conv (MonoMethodSignature *sig)
{
        return sig->call_convention;
}

/**
 * mono_signature_vararg_start:
 * \param sig the method signature inspected
 * \returns the number of the first vararg parameter in the
 * method signature \param sig. \c -1 if this is not a vararg signature.
 */
int
mono_signature_vararg_start (MonoMethodSignature *sig)
{
        return sig->sentinelpos;
}

/**
 * mono_signature_is_instance:
 * \param sig the method signature inspected
 * \returns TRUE if this the method signature \p sig has an implicit
 * first instance argument. FALSE otherwise.
 */
gboolean
mono_signature_is_instance (MonoMethodSignature *sig)
{
        return sig->hasthis;
}

/**
 * mono_signature_param_is_out
 * \param sig the method signature inspected
 * \param param_num the 0-based index of the inspected parameter
 * \returns TRUE if the parameter is an out parameter, FALSE
 * otherwise.
 */
mono_bool
mono_signature_param_is_out (MonoMethodSignature *sig, int param_num)
{
        g_assert (param_num >= 0 && param_num < sig->param_count);
        return (sig->params [param_num]->attrs & PARAM_ATTRIBUTE_OUT) != 0;
}

/**
 * mono_signature_explicit_this:
 * \param sig the method signature inspected
 * \returns TRUE if this the method signature \p sig has an explicit
 * instance argument. FALSE otherwise.
 */
gboolean
mono_signature_explicit_this (MonoMethodSignature *sig)
{
        return sig->explicit_this;
}

/* for use with allocated memory blocks (assumes alignment is to 8 bytes) */
guint
mono_aligned_addr_hash (gconstpointer ptr)
{
        /* Same hashing we use for objects */
        return (GPOINTER_TO_UINT (ptr) >> 3) * 2654435761u;
}

/*
 * If @field belongs to an inflated generic class, return the corresponding field of the
 * generic type definition class.
 */
MonoClassField*
mono_metadata_get_corresponding_field_from_generic_type_definition (MonoClassField *field)
{
        MonoClass *gtd;
        int offset;

        if (!mono_class_is_ginst (field->parent))
                return field;

        gtd = mono_class_get_generic_class (field->parent)->container_class;
        offset = field - m_class_get_fields (field->parent);
        return m_class_get_fields (gtd) + offset;
}

/*
 * If @event belongs to an inflated generic class, return the corresponding event of the
 * generic type definition class.
 */
MonoEvent*
mono_metadata_get_corresponding_event_from_generic_type_definition (MonoEvent *event)
{
        MonoClass *gtd;
        int offset;

        if (!mono_class_is_ginst (event->parent))
                return event;

        gtd = mono_class_get_generic_class (event->parent)->container_class;
        offset = event - mono_class_get_event_info (event->parent)->events;
        return mono_class_get_event_info (gtd)->events + offset;
}

/*
 * If @property belongs to an inflated generic class, return the corresponding property of the
 * generic type definition class.
 */
MonoProperty*
mono_metadata_get_corresponding_property_from_generic_type_definition (MonoProperty *property)
{
        MonoClassPropertyInfo *info;
        MonoClass *gtd;
        int offset;

        if (!mono_class_is_ginst (property->parent))
                return property;

        info = mono_class_get_property_info (property->parent);
        gtd = mono_class_get_generic_class (property->parent)->container_class;
        offset = property - info->properties;
        return mono_class_get_property_info (gtd)->properties + offset;
}

MonoWrapperCaches*
mono_method_get_wrapper_cache (MonoMethod *method)
{
        if (method->is_inflated) {
                MonoMethodInflated *imethod = (MonoMethodInflated *)method;
                return &imethod->owner->wrapper_caches;
        } else {
                return &m_class_get_image (method->klass)->wrapper_caches;
        }
}

// This is support for the mempool reference tracking feature in checked-build, but lives in metadata.c due to use of static variables of this file.

/**
 * mono_find_image_set_owner:
 *
 * Find the imageset, if any, which a given pointer is located in the memory of.
 */
MonoImageSet *
mono_find_image_set_owner (void *ptr)
{
        MonoImageSet *owner = NULL;
        int i;

        image_sets_lock ();

        if (image_sets)
        {
                for (i = 0; !owner && i < image_sets->len; ++i) {
                        MonoImageSet *set = (MonoImageSet *)g_ptr_array_index (image_sets, i);
                        if (mono_mempool_contains_addr (set->mempool, ptr))
                                owner = set;
                }
        }

        image_sets_unlock ();

        return owner;
}

void
mono_loader_set_strict_assembly_name_check (gboolean enabled)
{
        check_assembly_names_strictly = enabled;
}

gboolean
mono_loader_get_strict_assembly_name_check (void)
{
#if !defined(DISABLE_DESKTOP_LOADER) || defined(ENABLE_NETCORE)
        return check_assembly_names_strictly;
#else
        return FALSE;
#endif
}


gboolean
mono_type_is_aggregate_mods (const MonoType *t)
{
        if (!t->has_cmods)
                return FALSE;

        MonoTypeWithModifiers *full = (MonoTypeWithModifiers *)t;

        return full->is_aggregate;
}

MonoCustomModContainer *
mono_type_get_cmods (const MonoType *t)
{
        if (!t->has_cmods)
                return NULL;

        MonoTypeWithModifiers *full = (MonoTypeWithModifiers *)t;

        g_assert (!full->is_aggregate);
        return &full->mods.cmods;
}

MonoAggregateModContainer *
mono_type_get_amods (const MonoType *t)
{
        if (!t->has_cmods)
                return NULL;

        MonoTypeWithModifiers *full = (MonoTypeWithModifiers *)t;

        g_assert (full->is_aggregate);
        return full->mods.amods;
}

size_t
mono_sizeof_aggregate_modifiers (uint8_t num_mods)
{
        size_t accum = 0;
        accum += offsetof (MonoAggregateModContainer, modifiers);
        accum += sizeof (MonoSingleCustomMod) * num_mods;
        return accum;
}

size_t 
mono_sizeof_type_with_mods (uint8_t num_mods, gboolean is_aggregate)
{
        if (num_mods == 0)
                return sizeof (MonoType);
        size_t accum = 0;
        accum += offsetof (MonoTypeWithModifiers, mods);

        if (!is_aggregate) {
                accum += offsetof (struct _MonoCustomModContainer, modifiers);
                accum += sizeof (MonoCustomMod) * num_mods;
        } else {
                accum += offsetof (MonoAggregateModContainer, modifiers);
                accum += sizeof (MonoAggregateModContainer *);
        }
        return accum;
}

size_t 
mono_sizeof_type (const MonoType *ty)
{
        if (ty->has_cmods) {
                if (!mono_type_is_aggregate_mods (ty)) {
                        MonoCustomModContainer *cmods = mono_type_get_cmods (ty);
                        return mono_sizeof_type_with_mods (cmods->count, FALSE);
                } else {
                        MonoAggregateModContainer *amods = mono_type_get_amods (ty);
                        return mono_sizeof_type_with_mods (amods->count, TRUE);
                }
        } else
                return sizeof (MonoType);
}

void
mono_type_set_amods (MonoType *t, MonoAggregateModContainer *amods)
{
        g_assert (t->has_cmods);
        MonoTypeWithModifiers *t_full = (MonoTypeWithModifiers*)t;
        g_assert (t_full->is_aggregate);
        g_assert (t_full->mods.amods == NULL);
        t_full->mods.amods = amods;
}