mono/mini/aliasing.h

   1 /*
   2  * aliasing.h: Alias Analysis
   3  *
   4  * Author:
   5  *   Massimiliano Mantione (massi@ximian.com)
   6  *
   7  * (C) 2005 Novell, Inc.  http://www.novell.com
   8  */
   9
  10 #ifndef __MONO_ALIASING_H__
  11 #define __MONO_ALIASING_H__
  12
  13 #include "mini.h"
  14
  15 #define MONO_ALIASING_INVALID_VARIABLE_INDEX (-1)
  16
  17 /*
  18  * A struct representing the element of a list of local variables.
  19  */
  20 typedef struct MonoLocalVariableList {
  21         /* The index of the local variable */
  22         int variable_index;
  23
  24         /* Next in the list */
  25         struct MonoLocalVariableList *next;
  26 } MonoLocalVariableList;
  27
  28 /*
  29  * A struct representing the information about the fact that an address
  30  * that could be an alias is used.
  31  */
  32 typedef struct MonoAliasUsageInformation {
  33         /* The inst where the address is used */
  34         MonoInst *inst;
  35
  36         /* The possibly aliased variables. Note that if this field is null */
  37         /* it means that any "problematic" variable could be aliased! */
  38         MonoLocalVariableList *affected_variables;
  39
  40         /* Next in the list */
  41         struct MonoAliasUsageInformation *next;
  42 } MonoAliasUsageInformation;
  43
  44
  45 /*
  46  * All the different kinds of locations for a variable's address.
  47  * "ANY" means the location is unknown or cannot be handled.
  48  */
  49 typedef enum {
  50         MONO_ALIASING_TYPE_ANY,
  51         MONO_ALIASING_TYPE_NO_ALIAS,
  52         MONO_ALIASING_TYPE_LOCAL,
  53         MONO_ALIASING_TYPE_LOCAL_FIELD
  54 } MonoAliasType;
  55
  56 typedef struct MonoAliasValue {
  57         MonoAliasType type;
  58         int variable_index;
  59 } MonoAliasValue;
  60
  61 /*
  62  * A struct representing the aliasing information in a BB.
  63  */
  64 typedef struct MonoAliasingInformationInBB {
  65         /* The BB to which these info are relaed. */
  66         MonoBasicBlock *bb;
  67
  68         /* Info on alias usage. */
  69         MonoAliasUsageInformation *potential_alias_uses;
  70 } MonoAliasingInformationInBB;
  71
  72 /*
  73  * A struct representing the aliasing information in a MonoCompile.
  74  */
  75 typedef struct MonoAliasingInformation {
  76         /* The MonoCompile to which these info are relaed. */
  77         MonoCompile *cfg;
  78
  79         /* The pool from where everything is allocated (including this struct). */
  80         MonoMemPool *mempool;
  81
  82         /* Aliasing info for each BB */
  83         MonoAliasingInformationInBB *bb;
  84
  85         /* The variables whose address has been taken and "lost": any pointer */
  86         /* with an unknown value potentially aliases these variables. */
  87         MonoLocalVariableList *uncontrollably_aliased_variables;
  88
  89         /* Used to track the current inst when traversing inst trees in a BB. */
  90         MonoAliasUsageInformation *next_interesting_inst;
  91
  92         /* Array containing one MonoLocalVariableList for each local variable. */
  93         MonoLocalVariableList *variables;
  94
  95         /* Array containing one flag for each local variable stating if it is */
  96         /* already in the uncontrollably_aliased_variables list. */
  97         gboolean *variable_is_uncontrollably_aliased;
  98
  99         /* This MonoLocalVariableList is a placeholder for uncontrollably_aliased_variables */
 100         /* while the aliasing info are still being collected. */
 101         MonoLocalVariableList *temporary_uncontrollably_aliased_variables;
 102
 103         /* An array of MonoInst* containing all the arguments to the next call. */
 104         MonoInst **arguments;
 105         /* An array of MonoAliasValue containing all the aliases passed to the arguments of the next call. */
 106         MonoAliasValue *arguments_aliases;
 107         /* The total capacity of the "arguments" and "arguments_aliases" arrays. */
 108         int arguments_capacity;
 109         /* The number of used elements in the "arguments" and "arguments_aliases" arrays. */
 110         int number_of_arguments;
 111 } MonoAliasingInformation;
 112
 113 extern MonoAliasingInformation*
 114 mono_build_aliasing_information (MonoCompile *cfg) MONO_INTERNAL;
 115 extern void
 116 mono_destroy_aliasing_information (MonoAliasingInformation *info) MONO_INTERNAL;
 117 extern void
 118 mono_aliasing_initialize_code_traversal (MonoAliasingInformation *info, MonoBasicBlock *bb) MONO_INTERNAL;
 119 extern MonoLocalVariableList*
 120 mono_aliasing_get_affected_variables_for_inst_traversing_code (MonoAliasingInformation *info, MonoInst *inst) MONO_INTERNAL;
 121 extern MonoLocalVariableList*
 122 mono_aliasing_get_affected_variables_for_inst (MonoAliasingInformation *info, MonoInst *inst) MONO_INTERNAL;
 123
 124 extern void
 125 mono_aliasing_deadce (MonoAliasingInformation *info) MONO_INTERNAL;
 126
 127 #endif /* __MONO_ALIASING_H__ */