Modules/_ctypes/libffi_osx/ffi.c

   1 /* -----------------------------------------------------------------------
   2    prep_cif.c - Copyright (c) 1996, 1998  Red Hat, Inc.
   3
   4    Permission is hereby granted, free of charge, to any person obtaining
   5    a copy of this software and associated documentation files (the
   6    ``Software''), to deal in the Software without restriction, including
   7    without limitation the rights to use, copy, modify, merge, publish,
   8    distribute, sublicense, and/or sell copies of the Software, and to
   9    permit persons to whom the Software is furnished to do so, subject to
  10    the following conditions:
  11
  12    The above copyright notice and this permission notice shall be included
  13    in all copies or substantial portions of the Software.
  14
  15    THE SOFTWARE IS PROVIDED ``AS IS'', WITHOUT WARRANTY OF ANY KIND, EXPRESS
  16    OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
  17    MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
  18    IN NO EVENT SHALL CYGNUS SOLUTIONS BE LIABLE FOR ANY CLAIM, DAMAGES OR
  19    OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
  20    ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
  21    OTHER DEALINGS IN THE SOFTWARE.
  22    ----------------------------------------------------------------------- */
  23
  24 #include <ffi.h>
  25 #include <ffi_common.h>
  26
  27 #include <stdbool.h>
  28 #include <stdlib.h>
  29
  30 /* Round up to FFI_SIZEOF_ARG. */
  31 #define STACK_ARG_SIZE(x) ALIGN(x, FFI_SIZEOF_ARG)
  32
  33 /* Perform machine independent initialization of aggregate type
  34    specifications. */
  35
  36 static ffi_status
  37 initialize_aggregate(
  38 /*@out@*/       ffi_type*       arg)
  39 {
  40 /*@-usedef@*/
  41
  42         if (arg == NULL || arg->elements == NULL ||
  43                 arg->size != 0 || arg->alignment != 0)
  44                 return FFI_BAD_TYPEDEF;
  45
  46         ffi_type**      ptr = &(arg->elements[0]);
  47
  48         while ((*ptr) != NULL)
  49         {
  50                 if (((*ptr)->size == 0) && (initialize_aggregate(*ptr) != FFI_OK))
  51                         return FFI_BAD_TYPEDEF;
  52
  53                 /* Perform a sanity check on the argument type */
  54                 FFI_ASSERT_VALID_TYPE(*ptr);
  55
  56 #ifdef POWERPC_DARWIN
  57                 int curalign = (*ptr)->alignment;
  58
  59                 if (ptr != &(arg->elements[0]))
  60                 {
  61                         if (curalign > 4 && curalign != 16)
  62                                 curalign = 4;
  63                 }
  64
  65                 arg->size               = ALIGN(arg->size, curalign);
  66                 arg->size               += (*ptr)->size;
  67                 arg->alignment  = (arg->alignment > curalign) ?
  68                         arg->alignment : curalign;
  69 #else
  70                 arg->size               = ALIGN(arg->size, (*ptr)->alignment);
  71                 arg->size               += (*ptr)->size;
  72                 arg->alignment  = (arg->alignment > (*ptr)->alignment) ?
  73                         arg->alignment : (*ptr)->alignment;
  74 #endif
  75
  76                 ptr++;
  77     }
  78
  79   /* Structure size includes tail padding.  This is important for
  80      structures that fit in one register on ABIs like the PowerPC64
  81      Linux ABI that right justify small structs in a register.
  82      It's also needed for nested structure layout, for example
  83      struct A { long a; char b; }; struct B { struct A x; char y; };
  84      should find y at an offset of 2*sizeof(long) and result in a
  85      total size of 3*sizeof(long).  */
  86         arg->size = ALIGN(arg->size, arg->alignment);
  87
  88         if (arg->size == 0)
  89                 return FFI_BAD_TYPEDEF;
  90
  91         return FFI_OK;
  92
  93 /*@=usedef@*/
  94 }
  95
  96 #ifndef __CRIS__
  97 /* The CRIS ABI specifies structure elements to have byte
  98    alignment only, so it completely overrides this functions,
  99    which assumes "natural" alignment and padding.  */
 100
 101 /* Perform machine independent ffi_cif preparation, then call
 102    machine dependent routine. */
 103
 104 #if defined(X86_DARWIN)
 105
 106 static inline bool
 107 struct_on_stack(
 108         int     size)
 109 {
 110         if (size > 8)
 111                 return true;
 112
 113         /* This is not what the ABI says, but is what is really implemented */
 114         switch (size)
 115         {
 116                 case 1:
 117                 case 2:
 118                 case 4:
 119                 case 8:
 120                         return false;
 121
 122                 default:
 123                         return true;
 124         }
 125 }
 126
 127 #endif  // defined(X86_DARWIN)
 128
 129 // Arguments' ffi_type->alignment must be nonzero.
 130 ffi_status
 131 ffi_prep_cif(
 132 /*@out@*/ /*@partial@*/ ffi_cif*                cif,
 133                                                 ffi_abi                 abi,
 134                                                 unsigned int    nargs,
 135 /*@dependent@*/ /*@out@*/ /*@partial@*/ ffi_type*       rtype,
 136 /*@dependent@*/                 ffi_type**              atypes)
 137 {
 138         if (cif == NULL)
 139                 return FFI_BAD_TYPEDEF;
 140
 141         if (abi <= FFI_FIRST_ABI || abi > FFI_DEFAULT_ABI)
 142                 return FFI_BAD_ABI;
 143
 144         unsigned int    bytes   = 0;
 145         unsigned int    i;
 146         ffi_type**              ptr;
 147
 148         cif->abi = abi;
 149         cif->arg_types = atypes;
 150         cif->nargs = nargs;
 151         cif->rtype = rtype;
 152         cif->flags = 0;
 153
 154         /* Initialize the return type if necessary */
 155         /*@-usedef@*/
 156         if ((cif->rtype->size == 0) && (initialize_aggregate(cif->rtype) != FFI_OK))
 157                 return FFI_BAD_TYPEDEF;
 158         /*@=usedef@*/
 159
 160         /* Perform a sanity check on the return type */
 161         FFI_ASSERT_VALID_TYPE(cif->rtype);
 162
 163         /* x86-64 and s390 stack space allocation is handled in prep_machdep.  */
 164 #if !defined M68K && !defined __x86_64__ && !defined S390 && !defined PA
 165         /* Make space for the return structure pointer */
 166         if (cif->rtype->type == FFI_TYPE_STRUCT
 167 #ifdef SPARC
 168                 && (cif->abi != FFI_V9 || cif->rtype->size > 32)
 169 #endif
 170 #ifdef X86_DARWIN
 171                 && (struct_on_stack(cif->rtype->size))
 172 #endif
 173                 )
 174                 bytes = STACK_ARG_SIZE(sizeof(void*));
 175 #endif
 176
 177         for (ptr = cif->arg_types, i = cif->nargs; i > 0; i--, ptr++)
 178         {
 179                 /* Initialize any uninitialized aggregate type definitions */
 180                 if (((*ptr)->size == 0) && (initialize_aggregate((*ptr)) != FFI_OK))
 181                         return FFI_BAD_TYPEDEF;
 182
 183                 if ((*ptr)->alignment == 0)
 184                         return FFI_BAD_TYPEDEF;
 185
 186                 /* Perform a sanity check on the argument type, do this
 187                 check after the initialization.  */
 188                 FFI_ASSERT_VALID_TYPE(*ptr);
 189
 190 #if defined(X86_DARWIN)
 191                 {
 192                         int align = (*ptr)->alignment;
 193
 194                         if (align > 4)
 195                                 align = 4;
 196
 197                         if ((align - 1) & bytes)
 198                                 bytes = ALIGN(bytes, align);
 199
 200                         bytes += STACK_ARG_SIZE((*ptr)->size);
 201                 }
 202 #elif !defined __x86_64__ && !defined S390 && !defined PA
 203 #ifdef SPARC
 204                 if (((*ptr)->type == FFI_TYPE_STRUCT
 205                         && ((*ptr)->size > 16 || cif->abi != FFI_V9))
 206                         || ((*ptr)->type == FFI_TYPE_LONGDOUBLE
 207                         && cif->abi != FFI_V9))
 208                                 bytes += sizeof(void*);
 209                 else
 210 #endif
 211                 {
 212                         /* Add any padding if necessary */
 213                         if (((*ptr)->alignment - 1) & bytes)
 214                                 bytes = ALIGN(bytes, (*ptr)->alignment);
 215
 216                         bytes += STACK_ARG_SIZE((*ptr)->size);
 217                 }
 218 #endif
 219         }
 220
 221         cif->bytes = bytes;
 222
 223         /* Perform machine dependent cif processing */
 224         return ffi_prep_cif_machdep(cif);
 225 }
 226 #endif /* not __CRIS__ */