| /* Alias analysis for trees. |
| Copyright (C) 2004-2021 Free Software Foundation, Inc. |
| Contributed by Diego Novillo <dnovillo@redhat.com> |
| |
| This file is part of GCC. |
| |
| GCC is free software; you can redistribute it and/or modify |
| it under the terms of the GNU General Public License as published by |
| the Free Software Foundation; either version 3, or (at your option) |
| any later version. |
| |
| GCC is distributed in the hope that it will be useful, |
| but WITHOUT ANY WARRANTY; without even the implied warranty of |
| MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| GNU General Public License for more details. |
| |
| You should have received a copy of the GNU General Public License |
| along with GCC; see the file COPYING3. If not see |
| <http://www.gnu.org/licenses/>. */ |
| |
| #include "config.h" |
| #include "system.h" |
| #include "coretypes.h" |
| #include "backend.h" |
| #include "target.h" |
| #include "rtl.h" |
| #include "tree.h" |
| #include "gimple.h" |
| #include "timevar.h" /* for TV_ALIAS_STMT_WALK */ |
| #include "ssa.h" |
| #include "cgraph.h" |
| #include "tree-pretty-print.h" |
| #include "alias.h" |
| #include "fold-const.h" |
| #include "langhooks.h" |
| #include "dumpfile.h" |
| #include "tree-eh.h" |
| #include "tree-dfa.h" |
| #include "ipa-reference.h" |
| #include "varasm.h" |
| #include "ipa-modref-tree.h" |
| #include "ipa-modref.h" |
| #include "attr-fnspec.h" |
| #include "errors.h" |
| #include "dbgcnt.h" |
| #include "gimple-pretty-print.h" |
| #include "print-tree.h" |
| #include "tree-ssa-alias-compare.h" |
| #include "builtins.h" |
| |
| /* Broad overview of how alias analysis on gimple works: |
| |
| Statements clobbering or using memory are linked through the |
| virtual operand factored use-def chain. The virtual operand |
| is unique per function, its symbol is accessible via gimple_vop (cfun). |
| Virtual operands are used for efficiently walking memory statements |
| in the gimple IL and are useful for things like value-numbering as |
| a generation count for memory references. |
| |
| SSA_NAME pointers may have associated points-to information |
| accessible via the SSA_NAME_PTR_INFO macro. Flow-insensitive |
| points-to information is (re-)computed by the TODO_rebuild_alias |
| pass manager todo. Points-to information is also used for more |
| precise tracking of call-clobbered and call-used variables and |
| related disambiguations. |
| |
| This file contains functions for disambiguating memory references, |
| the so called alias-oracle and tools for walking of the gimple IL. |
| |
| The main alias-oracle entry-points are |
| |
| bool stmt_may_clobber_ref_p (gimple *, tree) |
| |
| This function queries if a statement may invalidate (parts of) |
| the memory designated by the reference tree argument. |
| |
| bool ref_maybe_used_by_stmt_p (gimple *, tree) |
| |
| This function queries if a statement may need (parts of) the |
| memory designated by the reference tree argument. |
| |
| There are variants of these functions that only handle the call |
| part of a statement, call_may_clobber_ref_p and ref_maybe_used_by_call_p. |
| Note that these do not disambiguate against a possible call lhs. |
| |
| bool refs_may_alias_p (tree, tree) |
| |
| This function tries to disambiguate two reference trees. |
| |
| bool ptr_deref_may_alias_global_p (tree) |
| |
| This function queries if dereferencing a pointer variable may |
| alias global memory. |
| |
| More low-level disambiguators are available and documented in |
| this file. Low-level disambiguators dealing with points-to |
| information are in tree-ssa-structalias.c. */ |
| |
| static int nonoverlapping_refs_since_match_p (tree, tree, tree, tree, bool); |
| static bool nonoverlapping_component_refs_p (const_tree, const_tree); |
| |
| /* Query statistics for the different low-level disambiguators. |
| A high-level query may trigger multiple of them. */ |
| |
| static struct { |
| unsigned HOST_WIDE_INT refs_may_alias_p_may_alias; |
| unsigned HOST_WIDE_INT refs_may_alias_p_no_alias; |
| unsigned HOST_WIDE_INT ref_maybe_used_by_call_p_may_alias; |
| unsigned HOST_WIDE_INT ref_maybe_used_by_call_p_no_alias; |
| unsigned HOST_WIDE_INT call_may_clobber_ref_p_may_alias; |
| unsigned HOST_WIDE_INT call_may_clobber_ref_p_no_alias; |
| unsigned HOST_WIDE_INT aliasing_component_refs_p_may_alias; |
| unsigned HOST_WIDE_INT aliasing_component_refs_p_no_alias; |
| unsigned HOST_WIDE_INT nonoverlapping_component_refs_p_may_alias; |
| unsigned HOST_WIDE_INT nonoverlapping_component_refs_p_no_alias; |
| unsigned HOST_WIDE_INT nonoverlapping_refs_since_match_p_may_alias; |
| unsigned HOST_WIDE_INT nonoverlapping_refs_since_match_p_must_overlap; |
| unsigned HOST_WIDE_INT nonoverlapping_refs_since_match_p_no_alias; |
| unsigned HOST_WIDE_INT modref_use_may_alias; |
| unsigned HOST_WIDE_INT modref_use_no_alias; |
| unsigned HOST_WIDE_INT modref_clobber_may_alias; |
| unsigned HOST_WIDE_INT modref_clobber_no_alias; |
| unsigned HOST_WIDE_INT modref_tests; |
| unsigned HOST_WIDE_INT modref_baseptr_tests; |
| } alias_stats; |
| |
| void |
| dump_alias_stats (FILE *s) |
| { |
| fprintf (s, "\nAlias oracle query stats:\n"); |
| fprintf (s, " refs_may_alias_p: " |
| HOST_WIDE_INT_PRINT_DEC" disambiguations, " |
| HOST_WIDE_INT_PRINT_DEC" queries\n", |
| alias_stats.refs_may_alias_p_no_alias, |
| alias_stats.refs_may_alias_p_no_alias |
| + alias_stats.refs_may_alias_p_may_alias); |
| fprintf (s, " ref_maybe_used_by_call_p: " |
| HOST_WIDE_INT_PRINT_DEC" disambiguations, " |
| HOST_WIDE_INT_PRINT_DEC" queries\n", |
| alias_stats.ref_maybe_used_by_call_p_no_alias, |
| alias_stats.refs_may_alias_p_no_alias |
| + alias_stats.ref_maybe_used_by_call_p_may_alias); |
| fprintf (s, " call_may_clobber_ref_p: " |
| HOST_WIDE_INT_PRINT_DEC" disambiguations, " |
| HOST_WIDE_INT_PRINT_DEC" queries\n", |
| alias_stats.call_may_clobber_ref_p_no_alias, |
| alias_stats.call_may_clobber_ref_p_no_alias |
| + alias_stats.call_may_clobber_ref_p_may_alias); |
| fprintf (s, " nonoverlapping_component_refs_p: " |
| HOST_WIDE_INT_PRINT_DEC" disambiguations, " |
| HOST_WIDE_INT_PRINT_DEC" queries\n", |
| alias_stats.nonoverlapping_component_refs_p_no_alias, |
| alias_stats.nonoverlapping_component_refs_p_no_alias |
| + alias_stats.nonoverlapping_component_refs_p_may_alias); |
| fprintf (s, " nonoverlapping_refs_since_match_p: " |
| HOST_WIDE_INT_PRINT_DEC" disambiguations, " |
| HOST_WIDE_INT_PRINT_DEC" must overlaps, " |
| HOST_WIDE_INT_PRINT_DEC" queries\n", |
| alias_stats.nonoverlapping_refs_since_match_p_no_alias, |
| alias_stats.nonoverlapping_refs_since_match_p_must_overlap, |
| alias_stats.nonoverlapping_refs_since_match_p_no_alias |
| + alias_stats.nonoverlapping_refs_since_match_p_may_alias |
| + alias_stats.nonoverlapping_refs_since_match_p_must_overlap); |
| fprintf (s, " aliasing_component_refs_p: " |
| HOST_WIDE_INT_PRINT_DEC" disambiguations, " |
| HOST_WIDE_INT_PRINT_DEC" queries\n", |
| alias_stats.aliasing_component_refs_p_no_alias, |
| alias_stats.aliasing_component_refs_p_no_alias |
| + alias_stats.aliasing_component_refs_p_may_alias); |
| dump_alias_stats_in_alias_c (s); |
| fprintf (s, "\nModref stats:\n"); |
| fprintf (s, " modref use: " |
| HOST_WIDE_INT_PRINT_DEC" disambiguations, " |
| HOST_WIDE_INT_PRINT_DEC" queries\n", |
| alias_stats.modref_use_no_alias, |
| alias_stats.modref_use_no_alias |
| + alias_stats.modref_use_may_alias); |
| fprintf (s, " modref clobber: " |
| HOST_WIDE_INT_PRINT_DEC" disambiguations, " |
| HOST_WIDE_INT_PRINT_DEC" queries\n" |
| " " HOST_WIDE_INT_PRINT_DEC" tbaa queries (%f per modref query)\n" |
| " " HOST_WIDE_INT_PRINT_DEC" base compares (%f per modref query)\n", |
| alias_stats.modref_clobber_no_alias, |
| alias_stats.modref_clobber_no_alias |
| + alias_stats.modref_clobber_may_alias, |
| alias_stats.modref_tests, |
| ((double)alias_stats.modref_tests) |
| / (alias_stats.modref_clobber_no_alias |
| + alias_stats.modref_clobber_may_alias), |
| alias_stats.modref_baseptr_tests, |
| ((double)alias_stats.modref_baseptr_tests) |
| / (alias_stats.modref_clobber_no_alias |
| + alias_stats.modref_clobber_may_alias)); |
| } |
| |
| |
| /* Return true, if dereferencing PTR may alias with a global variable. */ |
| |
| bool |
| ptr_deref_may_alias_global_p (tree ptr) |
| { |
| struct ptr_info_def *pi; |
| |
| /* If we end up with a pointer constant here that may point |
| to global memory. */ |
| if (TREE_CODE (ptr) != SSA_NAME) |
| return true; |
| |
| pi = SSA_NAME_PTR_INFO (ptr); |
| |
| /* If we do not have points-to information for this variable, |
| we have to punt. */ |
| if (!pi) |
| return true; |
| |
| /* ??? This does not use TBAA to prune globals ptr may not access. */ |
| return pt_solution_includes_global (&pi->pt); |
| } |
| |
| /* Return true if dereferencing PTR may alias DECL. |
| The caller is responsible for applying TBAA to see if PTR |
| may access DECL at all. */ |
| |
| static bool |
| ptr_deref_may_alias_decl_p (tree ptr, tree decl) |
| { |
| struct ptr_info_def *pi; |
| |
| /* Conversions are irrelevant for points-to information and |
| data-dependence analysis can feed us those. */ |
| STRIP_NOPS (ptr); |
| |
| /* Anything we do not explicilty handle aliases. */ |
| if ((TREE_CODE (ptr) != SSA_NAME |
| && TREE_CODE (ptr) != ADDR_EXPR |
| && TREE_CODE (ptr) != POINTER_PLUS_EXPR) |
| || !POINTER_TYPE_P (TREE_TYPE (ptr)) |
| || (!VAR_P (decl) |
| && TREE_CODE (decl) != PARM_DECL |
| && TREE_CODE (decl) != RESULT_DECL)) |
| return true; |
| |
| /* Disregard pointer offsetting. */ |
| if (TREE_CODE (ptr) == POINTER_PLUS_EXPR) |
| { |
| do |
| { |
| ptr = TREE_OPERAND (ptr, 0); |
| } |
| while (TREE_CODE (ptr) == POINTER_PLUS_EXPR); |
| return ptr_deref_may_alias_decl_p (ptr, decl); |
| } |
| |
| /* ADDR_EXPR pointers either just offset another pointer or directly |
| specify the pointed-to set. */ |
| if (TREE_CODE (ptr) == ADDR_EXPR) |
| { |
| tree base = get_base_address (TREE_OPERAND (ptr, 0)); |
| if (base |
| && (TREE_CODE (base) == MEM_REF |
| || TREE_CODE (base) == TARGET_MEM_REF)) |
| ptr = TREE_OPERAND (base, 0); |
| else if (base |
| && DECL_P (base)) |
| return compare_base_decls (base, decl) != 0; |
| else if (base |
| && CONSTANT_CLASS_P (base)) |
| return false; |
| else |
| return true; |
| } |
| |
| /* Non-aliased variables cannot be pointed to. */ |
| if (!may_be_aliased (decl)) |
| return false; |
| |
| /* If we do not have useful points-to information for this pointer |
| we cannot disambiguate anything else. */ |
| pi = SSA_NAME_PTR_INFO (ptr); |
| if (!pi) |
| return true; |
| |
| return pt_solution_includes (&pi->pt, decl); |
| } |
| |
| /* Return true if dereferenced PTR1 and PTR2 may alias. |
| The caller is responsible for applying TBAA to see if accesses |
| through PTR1 and PTR2 may conflict at all. */ |
| |
| bool |
| ptr_derefs_may_alias_p (tree ptr1, tree ptr2) |
| { |
| struct ptr_info_def *pi1, *pi2; |
| |
| /* Conversions are irrelevant for points-to information and |
| data-dependence analysis can feed us those. */ |
| STRIP_NOPS (ptr1); |
| STRIP_NOPS (ptr2); |
| |
| /* Disregard pointer offsetting. */ |
| if (TREE_CODE (ptr1) == POINTER_PLUS_EXPR) |
| { |
| do |
| { |
| ptr1 = TREE_OPERAND (ptr1, 0); |
| } |
| while (TREE_CODE (ptr1) == POINTER_PLUS_EXPR); |
| return ptr_derefs_may_alias_p (ptr1, ptr2); |
| } |
| if (TREE_CODE (ptr2) == POINTER_PLUS_EXPR) |
| { |
| do |
| { |
| ptr2 = TREE_OPERAND (ptr2, 0); |
| } |
| while (TREE_CODE (ptr2) == POINTER_PLUS_EXPR); |
| return ptr_derefs_may_alias_p (ptr1, ptr2); |
| } |
| |
| /* ADDR_EXPR pointers either just offset another pointer or directly |
| specify the pointed-to set. */ |
| if (TREE_CODE (ptr1) == ADDR_EXPR) |
| { |
| tree base = get_base_address (TREE_OPERAND (ptr1, 0)); |
| if (base |
| && (TREE_CODE (base) == MEM_REF |
| || TREE_CODE (base) == TARGET_MEM_REF)) |
| return ptr_derefs_may_alias_p (TREE_OPERAND (base, 0), ptr2); |
| else if (base |
| && DECL_P (base)) |
| return ptr_deref_may_alias_decl_p (ptr2, base); |
| else |
| return true; |
| } |
| if (TREE_CODE (ptr2) == ADDR_EXPR) |
| { |
| tree base = get_base_address (TREE_OPERAND (ptr2, 0)); |
| if (base |
| && (TREE_CODE (base) == MEM_REF |
| || TREE_CODE (base) == TARGET_MEM_REF)) |
| return ptr_derefs_may_alias_p (ptr1, TREE_OPERAND (base, 0)); |
| else if (base |
| && DECL_P (base)) |
| return ptr_deref_may_alias_decl_p (ptr1, base); |
| else |
| return true; |
| } |
| |
| /* From here we require SSA name pointers. Anything else aliases. */ |
| if (TREE_CODE (ptr1) != SSA_NAME |
| || TREE_CODE (ptr2) != SSA_NAME |
| || !POINTER_TYPE_P (TREE_TYPE (ptr1)) |
| || !POINTER_TYPE_P (TREE_TYPE (ptr2))) |
| return true; |
| |
| /* We may end up with two empty points-to solutions for two same pointers. |
| In this case we still want to say both pointers alias, so shortcut |
| that here. */ |
| if (ptr1 == ptr2) |
| return true; |
| |
| /* If we do not have useful points-to information for either pointer |
| we cannot disambiguate anything else. */ |
| pi1 = SSA_NAME_PTR_INFO (ptr1); |
| pi2 = SSA_NAME_PTR_INFO (ptr2); |
| if (!pi1 || !pi2) |
| return true; |
| |
| /* ??? This does not use TBAA to prune decls from the intersection |
| that not both pointers may access. */ |
| return pt_solutions_intersect (&pi1->pt, &pi2->pt); |
| } |
| |
| /* Return true if dereferencing PTR may alias *REF. |
| The caller is responsible for applying TBAA to see if PTR |
| may access *REF at all. */ |
| |
| static bool |
| ptr_deref_may_alias_ref_p_1 (tree ptr, ao_ref *ref) |
| { |
| tree base = ao_ref_base (ref); |
| |
| if (TREE_CODE (base) == MEM_REF |
| || TREE_CODE (base) == TARGET_MEM_REF) |
| return ptr_derefs_may_alias_p (ptr, TREE_OPERAND (base, 0)); |
| else if (DECL_P (base)) |
| return ptr_deref_may_alias_decl_p (ptr, base); |
| |
| return true; |
| } |
| |
| /* Returns true if PTR1 and PTR2 compare unequal because of points-to. */ |
| |
| bool |
| ptrs_compare_unequal (tree ptr1, tree ptr2) |
| { |
| /* First resolve the pointers down to a SSA name pointer base or |
| a VAR_DECL, PARM_DECL or RESULT_DECL. This explicitely does |
| not yet try to handle LABEL_DECLs, FUNCTION_DECLs, CONST_DECLs |
| or STRING_CSTs which needs points-to adjustments to track them |
| in the points-to sets. */ |
| tree obj1 = NULL_TREE; |
| tree obj2 = NULL_TREE; |
| if (TREE_CODE (ptr1) == ADDR_EXPR) |
| { |
| tree tem = get_base_address (TREE_OPERAND (ptr1, 0)); |
| if (! tem) |
| return false; |
| if (VAR_P (tem) |
| || TREE_CODE (tem) == PARM_DECL |
| || TREE_CODE (tem) == RESULT_DECL) |
| obj1 = tem; |
| else if (TREE_CODE (tem) == MEM_REF) |
| ptr1 = TREE_OPERAND (tem, 0); |
| } |
| if (TREE_CODE (ptr2) == ADDR_EXPR) |
| { |
| tree tem = get_base_address (TREE_OPERAND (ptr2, 0)); |
| if (! tem) |
| return false; |
| if (VAR_P (tem) |
| || TREE_CODE (tem) == PARM_DECL |
| || TREE_CODE (tem) == RESULT_DECL) |
| obj2 = tem; |
| else if (TREE_CODE (tem) == MEM_REF) |
| ptr2 = TREE_OPERAND (tem, 0); |
| } |
| |
| /* Canonicalize ptr vs. object. */ |
| if (TREE_CODE (ptr1) == SSA_NAME && obj2) |
| { |
| std::swap (ptr1, ptr2); |
| std::swap (obj1, obj2); |
| } |
| |
| if (obj1 && obj2) |
| /* Other code handles this correctly, no need to duplicate it here. */; |
| else if (obj1 && TREE_CODE (ptr2) == SSA_NAME) |
| { |
| struct ptr_info_def *pi = SSA_NAME_PTR_INFO (ptr2); |
| /* We may not use restrict to optimize pointer comparisons. |
| See PR71062. So we have to assume that restrict-pointed-to |
| may be in fact obj1. */ |
| if (!pi |
| || pi->pt.vars_contains_restrict |
| || pi->pt.vars_contains_interposable) |
| return false; |
| if (VAR_P (obj1) |
| && (TREE_STATIC (obj1) || DECL_EXTERNAL (obj1))) |
| { |
| varpool_node *node = varpool_node::get (obj1); |
| /* If obj1 may bind to NULL give up (see below). */ |
| if (! node |
| || ! node->nonzero_address () |
| || ! decl_binds_to_current_def_p (obj1)) |
| return false; |
| } |
| return !pt_solution_includes (&pi->pt, obj1); |
| } |
| |
| /* ??? We'd like to handle ptr1 != NULL and ptr1 != ptr2 |
| but those require pt.null to be conservatively correct. */ |
| |
| return false; |
| } |
| |
| /* Returns whether reference REF to BASE may refer to global memory. */ |
| |
| static bool |
| ref_may_alias_global_p_1 (tree base) |
| { |
| if (DECL_P (base)) |
| return is_global_var (base); |
| else if (TREE_CODE (base) == MEM_REF |
| || TREE_CODE (base) == TARGET_MEM_REF) |
| return ptr_deref_may_alias_global_p (TREE_OPERAND (base, 0)); |
| return true; |
| } |
| |
| bool |
| ref_may_alias_global_p (ao_ref *ref) |
| { |
| tree base = ao_ref_base (ref); |
| return ref_may_alias_global_p_1 (base); |
| } |
| |
| bool |
| ref_may_alias_global_p (tree ref) |
| { |
| tree base = get_base_address (ref); |
| return ref_may_alias_global_p_1 (base); |
| } |
| |
| /* Return true whether STMT may clobber global memory. */ |
| |
| bool |
| stmt_may_clobber_global_p (gimple *stmt) |
| { |
| tree lhs; |
| |
| if (!gimple_vdef (stmt)) |
| return false; |
| |
| /* ??? We can ask the oracle whether an artificial pointer |
| dereference with a pointer with points-to information covering |
| all global memory (what about non-address taken memory?) maybe |
| clobbered by this call. As there is at the moment no convenient |
| way of doing that without generating garbage do some manual |
| checking instead. |
| ??? We could make a NULL ao_ref argument to the various |
| predicates special, meaning any global memory. */ |
| |
| switch (gimple_code (stmt)) |
| { |
| case GIMPLE_ASSIGN: |
| lhs = gimple_assign_lhs (stmt); |
| return (TREE_CODE (lhs) != SSA_NAME |
| && ref_may_alias_global_p (lhs)); |
| case GIMPLE_CALL: |
| return true; |
| default: |
| return true; |
| } |
| } |
| |
| |
| /* Dump alias information on FILE. */ |
| |
| void |
| dump_alias_info (FILE *file) |
| { |
| unsigned i; |
| tree ptr; |
| const char *funcname |
| = lang_hooks.decl_printable_name (current_function_decl, 2); |
| tree var; |
| |
| fprintf (file, "\n\nAlias information for %s\n\n", funcname); |
| |
| fprintf (file, "Aliased symbols\n\n"); |
| |
| FOR_EACH_LOCAL_DECL (cfun, i, var) |
| { |
| if (may_be_aliased (var)) |
| dump_variable (file, var); |
| } |
| |
| fprintf (file, "\nCall clobber information\n"); |
| |
| fprintf (file, "\nESCAPED"); |
| dump_points_to_solution (file, &cfun->gimple_df->escaped); |
| |
| fprintf (file, "\n\nFlow-insensitive points-to information\n\n"); |
| |
| FOR_EACH_SSA_NAME (i, ptr, cfun) |
| { |
| struct ptr_info_def *pi; |
| |
| if (!POINTER_TYPE_P (TREE_TYPE (ptr)) |
| || SSA_NAME_IN_FREE_LIST (ptr)) |
| continue; |
| |
| pi = SSA_NAME_PTR_INFO (ptr); |
| if (pi) |
| dump_points_to_info_for (file, ptr); |
| } |
| |
| fprintf (file, "\n"); |
| } |
| |
| |
| /* Dump alias information on stderr. */ |
| |
| DEBUG_FUNCTION void |
| debug_alias_info (void) |
| { |
| dump_alias_info (stderr); |
| } |
| |
| |
| /* Dump the points-to set *PT into FILE. */ |
| |
| void |
| dump_points_to_solution (FILE *file, struct pt_solution *pt) |
| { |
| if (pt->anything) |
| fprintf (file, ", points-to anything"); |
| |
| if (pt->nonlocal) |
| fprintf (file, ", points-to non-local"); |
| |
| if (pt->escaped) |
| fprintf (file, ", points-to escaped"); |
| |
| if (pt->ipa_escaped) |
| fprintf (file, ", points-to unit escaped"); |
| |
| if (pt->null) |
| fprintf (file, ", points-to NULL"); |
| |
| if (pt->vars) |
| { |
| fprintf (file, ", points-to vars: "); |
| dump_decl_set (file, pt->vars); |
| if (pt->vars_contains_nonlocal |
| || pt->vars_contains_escaped |
| || pt->vars_contains_escaped_heap |
| || pt->vars_contains_restrict) |
| { |
| const char *comma = ""; |
| fprintf (file, " ("); |
| if (pt->vars_contains_nonlocal) |
| { |
| fprintf (file, "nonlocal"); |
| comma = ", "; |
| } |
| if (pt->vars_contains_escaped) |
| { |
| fprintf (file, "%sescaped", comma); |
| comma = ", "; |
| } |
| if (pt->vars_contains_escaped_heap) |
| { |
| fprintf (file, "%sescaped heap", comma); |
| comma = ", "; |
| } |
| if (pt->vars_contains_restrict) |
| { |
| fprintf (file, "%srestrict", comma); |
| comma = ", "; |
| } |
| if (pt->vars_contains_interposable) |
| fprintf (file, "%sinterposable", comma); |
| fprintf (file, ")"); |
| } |
| } |
| } |
| |
| |
| /* Unified dump function for pt_solution. */ |
| |
| DEBUG_FUNCTION void |
| debug (pt_solution &ref) |
| { |
| dump_points_to_solution (stderr, &ref); |
| } |
| |
| DEBUG_FUNCTION void |
| debug (pt_solution *ptr) |
| { |
| if (ptr) |
| debug (*ptr); |
| else |
| fprintf (stderr, "<nil>\n"); |
| } |
| |
| |
| /* Dump points-to information for SSA_NAME PTR into FILE. */ |
| |
| void |
| dump_points_to_info_for (FILE *file, tree ptr) |
| { |
| struct ptr_info_def *pi = SSA_NAME_PTR_INFO (ptr); |
| |
| print_generic_expr (file, ptr, dump_flags); |
| |
| if (pi) |
| dump_points_to_solution (file, &pi->pt); |
| else |
| fprintf (file, ", points-to anything"); |
| |
| fprintf (file, "\n"); |
| } |
| |
| |
| /* Dump points-to information for VAR into stderr. */ |
| |
| DEBUG_FUNCTION void |
| debug_points_to_info_for (tree var) |
| { |
| dump_points_to_info_for (stderr, var); |
| } |
| |
| |
| /* Initializes the alias-oracle reference representation *R from REF. */ |
| |
| void |
| ao_ref_init (ao_ref *r, tree ref) |
| { |
| r->ref = ref; |
| r->base = NULL_TREE; |
| r->offset = 0; |
| r->size = -1; |
| r->max_size = -1; |
| r->ref_alias_set = -1; |
| r->base_alias_set = -1; |
| r->volatile_p = ref ? TREE_THIS_VOLATILE (ref) : false; |
| } |
| |
| /* Returns the base object of the memory reference *REF. */ |
| |
| tree |
| ao_ref_base (ao_ref *ref) |
| { |
| bool reverse; |
| |
| if (ref->base) |
| return ref->base; |
| ref->base = get_ref_base_and_extent (ref->ref, &ref->offset, &ref->size, |
| &ref->max_size, &reverse); |
| return ref->base; |
| } |
| |
| /* Returns the base object alias set of the memory reference *REF. */ |
| |
| alias_set_type |
| ao_ref_base_alias_set (ao_ref *ref) |
| { |
| tree base_ref; |
| if (ref->base_alias_set != -1) |
| return ref->base_alias_set; |
| if (!ref->ref) |
| return 0; |
| base_ref = ref->ref; |
| while (handled_component_p (base_ref)) |
| base_ref = TREE_OPERAND (base_ref, 0); |
| ref->base_alias_set = get_alias_set (base_ref); |
| return ref->base_alias_set; |
| } |
| |
| /* Returns the reference alias set of the memory reference *REF. */ |
| |
| alias_set_type |
| ao_ref_alias_set (ao_ref *ref) |
| { |
| if (ref->ref_alias_set != -1) |
| return ref->ref_alias_set; |
| if (!ref->ref) |
| return 0; |
| ref->ref_alias_set = get_alias_set (ref->ref); |
| return ref->ref_alias_set; |
| } |
| |
| /* Returns a type satisfying |
| get_deref_alias_set (type) == ao_ref_base_alias_set (REF). */ |
| |
| tree |
| ao_ref_base_alias_ptr_type (ao_ref *ref) |
| { |
| tree base_ref; |
| |
| if (!ref->ref) |
| return NULL_TREE; |
| base_ref = ref->ref; |
| while (handled_component_p (base_ref)) |
| base_ref = TREE_OPERAND (base_ref, 0); |
| tree ret = reference_alias_ptr_type (base_ref); |
| return ret; |
| } |
| |
| /* Returns a type satisfying |
| get_deref_alias_set (type) == ao_ref_alias_set (REF). */ |
| |
| tree |
| ao_ref_alias_ptr_type (ao_ref *ref) |
| { |
| if (!ref->ref) |
| return NULL_TREE; |
| tree ret = reference_alias_ptr_type (ref->ref); |
| return ret; |
| } |
| |
| |
| /* Init an alias-oracle reference representation from a gimple pointer |
| PTR a range specified by OFFSET, SIZE and MAX_SIZE under the assumption |
| that RANGE_KNOWN is set. |
| |
| The access is assumed to be only to or after of the pointer target adjusted |
| by the offset, not before it (even in the case RANGE_KNOWN is false). */ |
| |
| static void |
| ao_ref_init_from_ptr_and_range (ao_ref *ref, tree ptr, |
| bool range_known, |
| poly_int64 offset, |
| poly_int64 size, |
| poly_int64 max_size) |
| { |
| poly_int64 t, extra_offset = 0; |
| |
| ref->ref = NULL_TREE; |
| if (TREE_CODE (ptr) == SSA_NAME) |
| { |
| gimple *stmt = SSA_NAME_DEF_STMT (ptr); |
| if (gimple_assign_single_p (stmt) |
| && gimple_assign_rhs_code (stmt) == ADDR_EXPR) |
| ptr = gimple_assign_rhs1 (stmt); |
| else if (is_gimple_assign (stmt) |
| && gimple_assign_rhs_code (stmt) == POINTER_PLUS_EXPR |
| && ptrdiff_tree_p (gimple_assign_rhs2 (stmt), &extra_offset)) |
| { |
| ptr = gimple_assign_rhs1 (stmt); |
| extra_offset *= BITS_PER_UNIT; |
| } |
| } |
| |
| if (TREE_CODE (ptr) == ADDR_EXPR) |
| { |
| ref->base = get_addr_base_and_unit_offset (TREE_OPERAND (ptr, 0), &t); |
| if (ref->base) |
| ref->offset = BITS_PER_UNIT * t; |
| else |
| { |
| range_known = false; |
| ref->offset = 0; |
| ref->base = get_base_address (TREE_OPERAND (ptr, 0)); |
| } |
| } |
| else |
| { |
| gcc_assert (POINTER_TYPE_P (TREE_TYPE (ptr))); |
| ref->base = build2 (MEM_REF, char_type_node, |
| ptr, null_pointer_node); |
| ref->offset = 0; |
| } |
| ref->offset += extra_offset + offset; |
| if (range_known) |
| { |
| ref->max_size = max_size; |
| ref->size = size; |
| } |
| else |
| ref->max_size = ref->size = -1; |
| ref->ref_alias_set = 0; |
| ref->base_alias_set = 0; |
| ref->volatile_p = false; |
| } |
| |
| /* Init an alias-oracle reference representation from a gimple pointer |
| PTR and a gimple size SIZE in bytes. If SIZE is NULL_TREE then the |
| size is assumed to be unknown. The access is assumed to be only |
| to or after of the pointer target, not before it. */ |
| |
| void |
| ao_ref_init_from_ptr_and_size (ao_ref *ref, tree ptr, tree size) |
| { |
| poly_int64 size_hwi; |
| if (size |
| && poly_int_tree_p (size, &size_hwi) |
| && coeffs_in_range_p (size_hwi, 0, HOST_WIDE_INT_MAX / BITS_PER_UNIT)) |
| { |
| size_hwi = size_hwi * BITS_PER_UNIT; |
| ao_ref_init_from_ptr_and_range (ref, ptr, true, 0, size_hwi, size_hwi); |
| } |
| else |
| ao_ref_init_from_ptr_and_range (ref, ptr, false, 0, -1, -1); |
| } |
| |
| /* S1 and S2 are TYPE_SIZE or DECL_SIZE. Compare them: |
| Return -1 if S1 < S2 |
| Return 1 if S1 > S2 |
| Return 0 if equal or incomparable. */ |
| |
| static int |
| compare_sizes (tree s1, tree s2) |
| { |
| if (!s1 || !s2) |
| return 0; |
| |
| poly_uint64 size1; |
| poly_uint64 size2; |
| |
| if (!poly_int_tree_p (s1, &size1) || !poly_int_tree_p (s2, &size2)) |
| return 0; |
| if (known_lt (size1, size2)) |
| return -1; |
| if (known_lt (size2, size1)) |
| return 1; |
| return 0; |
| } |
| |
| /* Compare TYPE1 and TYPE2 by its size. |
| Return -1 if size of TYPE1 < size of TYPE2 |
| Return 1 if size of TYPE1 > size of TYPE2 |
| Return 0 if types are of equal sizes or we can not compare them. */ |
| |
| static int |
| compare_type_sizes (tree type1, tree type2) |
| { |
| /* Be conservative for arrays and vectors. We want to support partial |
| overlap on int[3] and int[3] as tested in gcc.dg/torture/alias-2.c. */ |
| while (TREE_CODE (type1) == ARRAY_TYPE |
| || TREE_CODE (type1) == VECTOR_TYPE) |
| type1 = TREE_TYPE (type1); |
| while (TREE_CODE (type2) == ARRAY_TYPE |
| || TREE_CODE (type2) == VECTOR_TYPE) |
| type2 = TREE_TYPE (type2); |
| return compare_sizes (TYPE_SIZE (type1), TYPE_SIZE (type2)); |
| } |
| |
| /* Return 1 if TYPE1 and TYPE2 are to be considered equivalent for the |
| purpose of TBAA. Return 0 if they are distinct and -1 if we cannot |
| decide. */ |
| |
| static inline int |
| same_type_for_tbaa (tree type1, tree type2) |
| { |
| type1 = TYPE_MAIN_VARIANT (type1); |
| type2 = TYPE_MAIN_VARIANT (type2); |
| |
| /* Handle the most common case first. */ |
| if (type1 == type2) |
| return 1; |
| |
| /* If we would have to do structural comparison bail out. */ |
| if (TYPE_STRUCTURAL_EQUALITY_P (type1) |
| || TYPE_STRUCTURAL_EQUALITY_P (type2)) |
| return -1; |
| |
| /* Compare the canonical types. */ |
| if (TYPE_CANONICAL (type1) == TYPE_CANONICAL (type2)) |
| return 1; |
| |
| /* ??? Array types are not properly unified in all cases as we have |
| spurious changes in the index types for example. Removing this |
| causes all sorts of problems with the Fortran frontend. */ |
| if (TREE_CODE (type1) == ARRAY_TYPE |
| && TREE_CODE (type2) == ARRAY_TYPE) |
| return -1; |
| |
| /* ??? In Ada, an lvalue of an unconstrained type can be used to access an |
| object of one of its constrained subtypes, e.g. when a function with an |
| unconstrained parameter passed by reference is called on an object and |
| inlined. But, even in the case of a fixed size, type and subtypes are |
| not equivalent enough as to share the same TYPE_CANONICAL, since this |
| would mean that conversions between them are useless, whereas they are |
| not (e.g. type and subtypes can have different modes). So, in the end, |
| they are only guaranteed to have the same alias set. */ |
| alias_set_type set1 = get_alias_set (type1); |
| alias_set_type set2 = get_alias_set (type2); |
| if (set1 == set2) |
| return -1; |
| |
| /* Pointers to void are considered compatible with all other pointers, |
| so for two pointers see what the alias set resolution thinks. */ |
| if (POINTER_TYPE_P (type1) |
| && POINTER_TYPE_P (type2) |
| && alias_sets_conflict_p (set1, set2)) |
| return -1; |
| |
| /* The types are known to be not equal. */ |
| return 0; |
| } |
| |
| /* Return true if TYPE is a composite type (i.e. we may apply one of handled |
| components on it). */ |
| |
| static bool |
| type_has_components_p (tree type) |
| { |
| return AGGREGATE_TYPE_P (type) || VECTOR_TYPE_P (type) |
| || TREE_CODE (type) == COMPLEX_TYPE; |
| } |
| |
| /* MATCH1 and MATCH2 which are part of access path of REF1 and REF2 |
| respectively are either pointing to same address or are completely |
| disjoint. If PARTIAL_OVERLAP is true, assume that outermost arrays may |
| just partly overlap. |
| |
| Try to disambiguate using the access path starting from the match |
| and return false if there is no conflict. |
| |
| Helper for aliasing_component_refs_p. */ |
| |
| static bool |
| aliasing_matching_component_refs_p (tree match1, tree ref1, |
| poly_int64 offset1, poly_int64 max_size1, |
| tree match2, tree ref2, |
| poly_int64 offset2, poly_int64 max_size2, |
| bool partial_overlap) |
| { |
| poly_int64 offadj, sztmp, msztmp; |
| bool reverse; |
| |
| if (!partial_overlap) |
| { |
| get_ref_base_and_extent (match2, &offadj, &sztmp, &msztmp, &reverse); |
| offset2 -= offadj; |
| get_ref_base_and_extent (match1, &offadj, &sztmp, &msztmp, &reverse); |
| offset1 -= offadj; |
| if (!ranges_maybe_overlap_p (offset1, max_size1, offset2, max_size2)) |
| { |
| ++alias_stats.aliasing_component_refs_p_no_alias; |
| return false; |
| } |
| } |
| |
| int cmp = nonoverlapping_refs_since_match_p (match1, ref1, match2, ref2, |
| partial_overlap); |
| if (cmp == 1 |
| || (cmp == -1 && nonoverlapping_component_refs_p (ref1, ref2))) |
| { |
| ++alias_stats.aliasing_component_refs_p_no_alias; |
| return false; |
| } |
| ++alias_stats.aliasing_component_refs_p_may_alias; |
| return true; |
| } |
| |
| /* Return true if REF is reference to zero sized trailing array. I.e. |
| struct foo {int bar; int array[0];} *fooptr; |
| fooptr->array. */ |
| |
| static bool |
| component_ref_to_zero_sized_trailing_array_p (tree ref) |
| { |
| return (TREE_CODE (ref) == COMPONENT_REF |
| && TREE_CODE (TREE_TYPE (TREE_OPERAND (ref, 1))) == ARRAY_TYPE |
| && (!TYPE_SIZE (TREE_TYPE (TREE_OPERAND (ref, 1))) |
| || integer_zerop (TYPE_SIZE (TREE_TYPE (TREE_OPERAND (ref, 1))))) |
| && array_at_struct_end_p (ref)); |
| } |
| |
| /* Worker for aliasing_component_refs_p. Most parameters match parameters of |
| aliasing_component_refs_p. |
| |
| Walk access path REF2 and try to find type matching TYPE1 |
| (which is a start of possibly aliasing access path REF1). |
| If match is found, try to disambiguate. |
| |
| Return 0 for sucessful disambiguation. |
| Return 1 if match was found but disambiguation failed |
| Return -1 if there is no match. |
| In this case MAYBE_MATCH is set to 0 if there is no type matching TYPE1 |
| in access patch REF2 and -1 if we are not sure. */ |
| |
| static int |
| aliasing_component_refs_walk (tree ref1, tree type1, tree base1, |
| poly_int64 offset1, poly_int64 max_size1, |
| tree end_struct_ref1, |
| tree ref2, tree base2, |
| poly_int64 offset2, poly_int64 max_size2, |
| bool *maybe_match) |
| { |
| tree ref = ref2; |
| int same_p = 0; |
| |
| while (true) |
| { |
| /* We walk from inner type to the outer types. If type we see is |
| already too large to be part of type1, terminate the search. */ |
| int cmp = compare_type_sizes (type1, TREE_TYPE (ref)); |
| |
| if (cmp < 0 |
| && (!end_struct_ref1 |
| || compare_type_sizes (TREE_TYPE (end_struct_ref1), |
| TREE_TYPE (ref)) < 0)) |
| break; |
| /* If types may be of same size, see if we can decide about their |
| equality. */ |
| if (cmp == 0) |
| { |
| same_p = same_type_for_tbaa (TREE_TYPE (ref), type1); |
| if (same_p == 1) |
| break; |
| /* In case we can't decide whether types are same try to |
| continue looking for the exact match. |
| Remember however that we possibly saw a match |
| to bypass the access path continuations tests we do later. */ |
| if (same_p == -1) |
| *maybe_match = true; |
| } |
| if (!handled_component_p (ref)) |
| break; |
| ref = TREE_OPERAND (ref, 0); |
| } |
| if (same_p == 1) |
| { |
| bool partial_overlap = false; |
| |
| /* We assume that arrays can overlap by multiple of their elements |
| size as tested in gcc.dg/torture/alias-2.c. |
| This partial overlap happen only when both arrays are bases of |
| the access and not contained within another component ref. |
| To be safe we also assume partial overlap for VLAs. */ |
| if (TREE_CODE (TREE_TYPE (base1)) == ARRAY_TYPE |
| && (!TYPE_SIZE (TREE_TYPE (base1)) |
| || TREE_CODE (TYPE_SIZE (TREE_TYPE (base1))) != INTEGER_CST |
| || ref == base2)) |
| { |
| /* Setting maybe_match to true triggers |
| nonoverlapping_component_refs_p test later that still may do |
| useful disambiguation. */ |
| *maybe_match = true; |
| partial_overlap = true; |
| } |
| return aliasing_matching_component_refs_p (base1, ref1, |
| offset1, max_size1, |
| ref, ref2, |
| offset2, max_size2, |
| partial_overlap); |
| } |
| return -1; |
| } |
| |
| /* Consider access path1 base1....ref1 and access path2 base2...ref2. |
| Return true if they can be composed to single access path |
| base1...ref1...base2...ref2. |
| |
| REF_TYPE1 if type of REF1. END_STRUCT_PAST_END1 is true if there is |
| a trailing array access after REF1 in the non-TBAA part of the access. |
| REF1_ALIAS_SET is the alias set of REF1. |
| |
| BASE_TYPE2 is type of base2. END_STRUCT_REF2 is non-NULL if there is |
| a trailing array access in the TBAA part of access path2. |
| BASE2_ALIAS_SET is the alias set of base2. */ |
| |
| bool |
| access_path_may_continue_p (tree ref_type1, bool end_struct_past_end1, |
| alias_set_type ref1_alias_set, |
| tree base_type2, tree end_struct_ref2, |
| alias_set_type base2_alias_set) |
| { |
| /* Access path can not continue past types with no components. */ |
| if (!type_has_components_p (ref_type1)) |
| return false; |
| |
| /* If first access path ends by too small type to hold base of |
| the second access path, typically paths can not continue. |
| |
| Punt if end_struct_past_end1 is true. We want to support arbitrary |
| type puning past first COMPONENT_REF to union because redundant store |
| elimination depends on this, see PR92152. For this reason we can not |
| check size of the reference because types may partially overlap. */ |
| if (!end_struct_past_end1) |
| { |
| if (compare_type_sizes (ref_type1, base_type2) < 0) |
| return false; |
| /* If the path2 contains trailing array access we can strenghten the check |
| to verify that also the size of element of the trailing array fits. |
| In fact we could check for offset + type_size, but we do not track |
| offsets and this is quite side case. */ |
| if (end_struct_ref2 |
| && compare_type_sizes (ref_type1, TREE_TYPE (end_struct_ref2)) < 0) |
| return false; |
| } |
| return (base2_alias_set == ref1_alias_set |
| || alias_set_subset_of (base2_alias_set, ref1_alias_set)); |
| } |
| |
| /* Determine if the two component references REF1 and REF2 which are |
| based on access types TYPE1 and TYPE2 and of which at least one is based |
| on an indirect reference may alias. |
| REF1_ALIAS_SET, BASE1_ALIAS_SET, REF2_ALIAS_SET and BASE2_ALIAS_SET |
| are the respective alias sets. */ |
| |
| static bool |
| aliasing_component_refs_p (tree ref1, |
| alias_set_type ref1_alias_set, |
| alias_set_type base1_alias_set, |
| poly_int64 offset1, poly_int64 max_size1, |
| tree ref2, |
| alias_set_type ref2_alias_set, |
| alias_set_type base2_alias_set, |
| poly_int64 offset2, poly_int64 max_size2) |
| { |
| /* If one reference is a component references through pointers try to find a |
| common base and apply offset based disambiguation. This handles |
| for example |
| struct A { int i; int j; } *q; |
| struct B { struct A a; int k; } *p; |
| disambiguating q->i and p->a.j. */ |
| tree base1, base2; |
| tree type1, type2; |
| bool maybe_match = false; |
| tree end_struct_ref1 = NULL, end_struct_ref2 = NULL; |
| bool end_struct_past_end1 = false; |
| bool end_struct_past_end2 = false; |
| |
| /* Choose bases and base types to search for. |
| The access path is as follows: |
| base....end_of_tbaa_ref...actual_ref |
| At one place in the access path may be a reference to zero sized or |
| trailing array. |
| |
| We generally discard the segment after end_of_tbaa_ref however |
| we need to be careful in case it contains zero sized or trailing array. |
| These may happen after reference to union and in this case we need to |
| not disambiguate type puning scenarios. |
| |
| We set: |
| base1 to point to base |
| |
| ref1 to point to end_of_tbaa_ref |
| |
| end_struct_ref1 to point the trailing reference (if it exists |
| in range base....end_of_tbaa_ref |
| |
| end_struct_past_end1 is true if this trailing reference occurs in |
| end_of_tbaa_ref...actual_ref. */ |
| base1 = ref1; |
| while (handled_component_p (base1)) |
| { |
| /* Generally access paths are monotous in the size of object. The |
| exception are trailing arrays of structures. I.e. |
| struct a {int array[0];}; |
| or |
| struct a {int array1[0]; int array[];}; |
| Such struct has size 0 but accesses to a.array may have non-zero size. |
| In this case the size of TREE_TYPE (base1) is smaller than |
| size of TREE_TYPE (TREE_OPERAND (base1, 0)). |
| |
| Because we compare sizes of arrays just by sizes of their elements, |
| we only need to care about zero sized array fields here. */ |
| if (component_ref_to_zero_sized_trailing_array_p (base1)) |
| { |
| gcc_checking_assert (!end_struct_ref1); |
| end_struct_ref1 = base1; |
| } |
| if (ends_tbaa_access_path_p (base1)) |
| { |
| ref1 = TREE_OPERAND (base1, 0); |
| if (end_struct_ref1) |
| { |
| end_struct_past_end1 = true; |
| end_struct_ref1 = NULL; |
| } |
| } |
| base1 = TREE_OPERAND (base1, 0); |
| } |
| type1 = TREE_TYPE (base1); |
| base2 = ref2; |
| while (handled_component_p (base2)) |
| { |
| if (component_ref_to_zero_sized_trailing_array_p (base2)) |
| { |
| gcc_checking_assert (!end_struct_ref2); |
| end_struct_ref2 = base2; |
| } |
| if (ends_tbaa_access_path_p (base2)) |
| { |
| ref2 = TREE_OPERAND (base2, 0); |
| if (end_struct_ref2) |
| { |
| end_struct_past_end2 = true; |
| end_struct_ref2 = NULL; |
| } |
| } |
| base2 = TREE_OPERAND (base2, 0); |
| } |
| type2 = TREE_TYPE (base2); |
| |
| /* Now search for the type1 in the access path of ref2. This |
| would be a common base for doing offset based disambiguation on. |
| This however only makes sense if type2 is big enough to hold type1. */ |
| int cmp_outer = compare_type_sizes (type2, type1); |
| |
| /* If type2 is big enough to contain type1 walk its access path. |
| We also need to care of arrays at the end of structs that may extend |
| beyond the end of structure. If this occurs in the TBAA part of the |
| access path, we need to consider the increased type as well. */ |
| if (cmp_outer >= 0 |
| || (end_struct_ref2 |
| && compare_type_sizes (TREE_TYPE (end_struct_ref2), type1) >= 0)) |
| { |
| int res = aliasing_component_refs_walk (ref1, type1, base1, |
| offset1, max_size1, |
| end_struct_ref1, |
| ref2, base2, offset2, max_size2, |
| &maybe_match); |
| if (res != -1) |
| return res; |
| } |
| |
| /* If we didn't find a common base, try the other way around. */ |
| if (cmp_outer <= 0 |
| || (end_struct_ref1 |
| && compare_type_sizes (TREE_TYPE (end_struct_ref1), type1) <= 0)) |
| { |
| int res = aliasing_component_refs_walk (ref2, type2, base2, |
| offset2, max_size2, |
| end_struct_ref2, |
| ref1, base1, offset1, max_size1, |
| &maybe_match); |
| if (res != -1) |
| return res; |
| } |
| |
| /* In the following code we make an assumption that the types in access |
| paths do not overlap and thus accesses alias only if one path can be |
| continuation of another. If we was not able to decide about equivalence, |
| we need to give up. */ |
| if (maybe_match) |
| { |
| if (!nonoverlapping_component_refs_p (ref1, ref2)) |
| { |
| ++alias_stats.aliasing_component_refs_p_may_alias; |
| return true; |
| } |
| ++alias_stats.aliasing_component_refs_p_no_alias; |
| return false; |
| } |
| |
| if (access_path_may_continue_p (TREE_TYPE (ref1), end_struct_past_end1, |
| ref1_alias_set, |
| type2, end_struct_ref2, |
| base2_alias_set) |
| || access_path_may_continue_p (TREE_TYPE (ref2), end_struct_past_end2, |
| ref2_alias_set, |
| type1, end_struct_ref1, |
| base1_alias_set)) |
| { |
| ++alias_stats.aliasing_component_refs_p_may_alias; |
| return true; |
| } |
| ++alias_stats.aliasing_component_refs_p_no_alias; |
| return false; |
| } |
| |
| /* FIELD1 and FIELD2 are two fields of component refs. We assume |
| that bases of both component refs are either equivalent or nonoverlapping. |
| We do not assume that the containers of FIELD1 and FIELD2 are of the |
| same type or size. |
| |
| Return 0 in case the base address of component_refs are same then |
| FIELD1 and FIELD2 have same address. Note that FIELD1 and FIELD2 |
| may not be of same type or size. |
| |
| Return 1 if FIELD1 and FIELD2 are non-overlapping. |
| |
| Return -1 otherwise. |
| |
| Main difference between 0 and -1 is to let |
| nonoverlapping_component_refs_since_match_p discover the semantically |
| equivalent part of the access path. |
| |
| Note that this function is used even with -fno-strict-aliasing |
| and makes use of no TBAA assumptions. */ |
| |
| static int |
| nonoverlapping_component_refs_p_1 (const_tree field1, const_tree field2) |
| { |
| /* If both fields are of the same type, we could save hard work of |
| comparing offsets. */ |
| tree type1 = DECL_CONTEXT (field1); |
| tree type2 = DECL_CONTEXT (field2); |
| |
| if (TREE_CODE (type1) == RECORD_TYPE |
| && DECL_BIT_FIELD_REPRESENTATIVE (field1)) |
| field1 = DECL_BIT_FIELD_REPRESENTATIVE (field1); |
| if (TREE_CODE (type2) == RECORD_TYPE |
| && DECL_BIT_FIELD_REPRESENTATIVE (field2)) |
| field2 = DECL_BIT_FIELD_REPRESENTATIVE (field2); |
| |
| /* ??? Bitfields can overlap at RTL level so punt on them. |
| FIXME: RTL expansion should be fixed by adjusting the access path |
| when producing MEM_ATTRs for MEMs which are wider than |
| the bitfields similarly as done in set_mem_attrs_minus_bitpos. */ |
| if (DECL_BIT_FIELD (field1) && DECL_BIT_FIELD (field2)) |
| return -1; |
| |
| /* Assume that different FIELD_DECLs never overlap within a RECORD_TYPE. */ |
| if (type1 == type2 && TREE_CODE (type1) == RECORD_TYPE) |
| return field1 != field2; |
| |
| /* In common case the offsets and bit offsets will be the same. |
| However if frontends do not agree on the alignment, they may be |
| different even if they actually represent same address. |
| Try the common case first and if that fails calcualte the |
| actual bit offset. */ |
| if (tree_int_cst_equal (DECL_FIELD_OFFSET (field1), |
| DECL_FIELD_OFFSET (field2)) |
| && tree_int_cst_equal (DECL_FIELD_BIT_OFFSET (field1), |
| DECL_FIELD_BIT_OFFSET (field2))) |
| return 0; |
| |
| /* Note that it may be possible to use component_ref_field_offset |
| which would provide offsets as trees. However constructing and folding |
| trees is expensive and does not seem to be worth the compile time |
| cost. */ |
| |
| poly_uint64 offset1, offset2; |
| poly_uint64 bit_offset1, bit_offset2; |
| |
| if (poly_int_tree_p (DECL_FIELD_OFFSET (field1), &offset1) |
| && poly_int_tree_p (DECL_FIELD_OFFSET (field2), &offset2) |
| && poly_int_tree_p (DECL_FIELD_BIT_OFFSET (field1), &bit_offset1) |
| && poly_int_tree_p (DECL_FIELD_BIT_OFFSET (field2), &bit_offset2)) |
| { |
| offset1 = (offset1 << LOG2_BITS_PER_UNIT) + bit_offset1; |
| offset2 = (offset2 << LOG2_BITS_PER_UNIT) + bit_offset2; |
| |
| if (known_eq (offset1, offset2)) |
| return 0; |
| |
| poly_uint64 size1, size2; |
| |
| if (poly_int_tree_p (DECL_SIZE (field1), &size1) |
| && poly_int_tree_p (DECL_SIZE (field2), &size2) |
| && !ranges_maybe_overlap_p (offset1, size1, offset2, size2)) |
| return 1; |
| } |
| /* Resort to slower overlap checking by looking for matching types in |
| the middle of access path. */ |
| return -1; |
| } |
| |
| /* Return low bound of array. Do not produce new trees |
| and thus do not care about particular type of integer constant |
| and placeholder exprs. */ |
| |
| static tree |
| cheap_array_ref_low_bound (tree ref) |
| { |
| tree domain_type = TYPE_DOMAIN (TREE_TYPE (TREE_OPERAND (ref, 0))); |
| |
| /* Avoid expensive array_ref_low_bound. |
| low bound is either stored in operand2, or it is TYPE_MIN_VALUE of domain |
| type or it is zero. */ |
| if (TREE_OPERAND (ref, 2)) |
| return TREE_OPERAND (ref, 2); |
| else if (domain_type && TYPE_MIN_VALUE (domain_type)) |
| return TYPE_MIN_VALUE (domain_type); |
| else |
| return integer_zero_node; |
| } |
| |
| /* REF1 and REF2 are ARRAY_REFs with either same base address or which are |
| completely disjoint. |
| |
| Return 1 if the refs are non-overlapping. |
| Return 0 if they are possibly overlapping but if so the overlap again |
| starts on the same address. |
| Return -1 otherwise. */ |
| |
| int |
| nonoverlapping_array_refs_p (tree ref1, tree ref2) |
| { |
| tree index1 = TREE_OPERAND (ref1, 1); |
| tree index2 = TREE_OPERAND (ref2, 1); |
| tree low_bound1 = cheap_array_ref_low_bound (ref1); |
| tree low_bound2 = cheap_array_ref_low_bound (ref2); |
| |
| /* Handle zero offsets first: we do not need to match type size in this |
| case. */ |
| if (operand_equal_p (index1, low_bound1, 0) |
| && operand_equal_p (index2, low_bound2, 0)) |
| return 0; |
| |
| /* If type sizes are different, give up. |
| |
| Avoid expensive array_ref_element_size. |
| If operand 3 is present it denotes size in the alignmnet units. |
| Otherwise size is TYPE_SIZE of the element type. |
| Handle only common cases where types are of the same "kind". */ |
| if ((TREE_OPERAND (ref1, 3) == NULL) != (TREE_OPERAND (ref2, 3) == NULL)) |
| return -1; |
| |
| tree elmt_type1 = TREE_TYPE (TREE_TYPE (TREE_OPERAND (ref1, 0))); |
| tree elmt_type2 = TREE_TYPE (TREE_TYPE (TREE_OPERAND (ref2, 0))); |
| |
| if (TREE_OPERAND (ref1, 3)) |
| { |
| if (TYPE_ALIGN (elmt_type1) != TYPE_ALIGN (elmt_type2) |
| || !operand_equal_p (TREE_OPERAND (ref1, 3), |
| TREE_OPERAND (ref2, 3), 0)) |
| return -1; |
| } |
| else |
| { |
| if (!operand_equal_p (TYPE_SIZE_UNIT (elmt_type1), |
| TYPE_SIZE_UNIT (elmt_type2), 0)) |
| return -1; |
| } |
| |
| /* Since we know that type sizes are the same, there is no need to return |
| -1 after this point. Partial overlap can not be introduced. */ |
| |
| /* We may need to fold trees in this case. |
| TODO: Handle integer constant case at least. */ |
| if (!operand_equal_p (low_bound1, low_bound2, 0)) |
| return 0; |
| |
| if (TREE_CODE (index1) == INTEGER_CST && TREE_CODE (index2) == INTEGER_CST) |
| { |
| if (tree_int_cst_equal (index1, index2)) |
| return 0; |
| return 1; |
| } |
| /* TODO: We can use VRP to further disambiguate here. */ |
| return 0; |
| } |
| |
| /* Try to disambiguate REF1 and REF2 under the assumption that MATCH1 and |
| MATCH2 either point to the same address or are disjoint. |
| MATCH1 and MATCH2 are assumed to be ref in the access path of REF1 and REF2 |
| respectively or NULL in the case we established equivalence of bases. |
| If PARTIAL_OVERLAP is true assume that the toplevel arrays may actually |
| overlap by exact multiply of their element size. |
| |
| This test works by matching the initial segment of the access path |
| and does not rely on TBAA thus is safe for !flag_strict_aliasing if |
| match was determined without use of TBAA oracle. |
| |
| Return 1 if we can determine that component references REF1 and REF2, |
| that are within a common DECL, cannot overlap. |
| |
| Return 0 if paths are same and thus there is nothing to disambiguate more |
| (i.e. there is must alias assuming there is must alias between MATCH1 and |
| MATCH2) |
| |
| Return -1 if we can not determine 0 or 1 - this happens when we met |
| non-matching types was met in the path. |
| In this case it may make sense to continue by other disambiguation |
| oracles. */ |
| |
| static int |
| nonoverlapping_refs_since_match_p (tree match1, tree ref1, |
| tree match2, tree ref2, |
| bool partial_overlap) |
| { |
| int ntbaa1 = 0, ntbaa2 = 0; |
| /* Early return if there are no references to match, we do not need |
| to walk the access paths. |
| |
| Do not consider this as may-alias for stats - it is more useful |
| to have information how many disambiguations happened provided that |
| the query was meaningful. */ |
| |
| if (match1 == ref1 || !handled_component_p (ref1) |
| || match2 == ref2 || !handled_component_p (ref2)) |
| return -1; |
| |
| auto_vec<tree, 16> component_refs1; |
| auto_vec<tree, 16> component_refs2; |
| |
| /* Create the stack of handled components for REF1. */ |
| while (handled_component_p (ref1) && ref1 != match1) |
| { |
| /* We use TBAA only to re-synchronize after mismatched refs. So we |
| do not need to truncate access path after TBAA part ends. */ |
| if (ends_tbaa_access_path_p (ref1)) |
| ntbaa1 = 0; |
| else |
| ntbaa1++; |
| component_refs1.safe_push (ref1); |
| ref1 = TREE_OPERAND (ref1, 0); |
| } |
| |
| /* Create the stack of handled components for REF2. */ |
| while (handled_component_p (ref2) && ref2 != match2) |
| { |
| if (ends_tbaa_access_path_p (ref2)) |
| ntbaa2 = 0; |
| else |
| ntbaa2++; |
| component_refs2.safe_push (ref2); |
| ref2 = TREE_OPERAND (ref2, 0); |
| } |
| |
| if (!flag_strict_aliasing) |
| { |
| ntbaa1 = 0; |
| ntbaa2 = 0; |
| } |
| |
| bool mem_ref1 = TREE_CODE (ref1) == MEM_REF && ref1 != match1; |
| bool mem_ref2 = TREE_CODE (ref2) == MEM_REF && ref2 != match2; |
| |
| /* If only one of access path starts with MEM_REF check that offset is 0 |
| so the addresses stays the same after stripping it. |
| TODO: In this case we may walk the other access path until we get same |
| offset. |
| |
| If both starts with MEM_REF, offset has to be same. */ |
| if ((mem_ref1 && !mem_ref2 && !integer_zerop (TREE_OPERAND (ref1, 1))) |
| || (mem_ref2 && !mem_ref1 && !integer_zerop (TREE_OPERAND (ref2, 1))) |
| || (mem_ref1 && mem_ref2 |
| && !tree_int_cst_equal (TREE_OPERAND (ref1, 1), |
| TREE_OPERAND (ref2, 1)))) |
| { |
| ++alias_stats.nonoverlapping_refs_since_match_p_may_alias; |
| return -1; |
| } |
| |
| /* TARGET_MEM_REF are never wrapped in handled components, so we do not need |
| to handle them here at all. */ |
| gcc_checking_assert (TREE_CODE (ref1) != TARGET_MEM_REF |
| && TREE_CODE (ref2) != TARGET_MEM_REF); |
| |
| /* Pop the stacks in parallel and examine the COMPONENT_REFs of the same |
| rank. This is sufficient because we start from the same DECL and you |
| cannot reference several fields at a time with COMPONENT_REFs (unlike |
| with ARRAY_RANGE_REFs for arrays) so you always need the same number |
| of them to access a sub-component, unless you're in a union, in which |
| case the return value will precisely be false. */ |
| while (true) |
| { |
| /* Track if we seen unmatched ref with non-zero offset. In this case |
| we must look for partial overlaps. */ |
| bool seen_unmatched_ref_p = false; |
| |
| /* First match ARRAY_REFs an try to disambiguate. */ |
| if (!component_refs1.is_empty () |
| && !component_refs2.is_empty ()) |
| { |
| unsigned int narray_refs1=0, narray_refs2=0; |
| |
| /* We generally assume that both access paths starts by same sequence |
| of refs. However if number of array refs is not in sync, try |
| to recover and pop elts until number match. This helps the case |
| where one access path starts by array and other by element. */ |
| for (narray_refs1 = 0; narray_refs1 < component_refs1.length (); |
| narray_refs1++) |
| if (TREE_CODE (component_refs1 [component_refs1.length() |
| - 1 - narray_refs1]) != ARRAY_REF) |
| break; |
| |
| for (narray_refs2 = 0; narray_refs2 < component_refs2.length (); |
| narray_refs2++) |
| if (TREE_CODE (component_refs2 [component_refs2.length() |
| - 1 - narray_refs2]) != ARRAY_REF) |
| break; |
| for (; narray_refs1 > narray_refs2; narray_refs1--) |
| { |
| ref1 = component_refs1.pop (); |
| ntbaa1--; |
| |
| /* If index is non-zero we need to check whether the reference |
| does not break the main invariant that bases are either |
| disjoint or equal. Consider the example: |
| |
| unsigned char out[][1]; |
| out[1]="a"; |
| out[i][0]; |
| |
| Here bases out and out are same, but after removing the |
| [i] index, this invariant no longer holds, because |
| out[i] points to the middle of array out. |
| |
| TODO: If size of type of the skipped reference is an integer |
| multiply of the size of type of the other reference this |
| invariant can be verified, but even then it is not completely |
| safe with !flag_strict_aliasing if the other reference contains |
| unbounded array accesses. |
| See */ |
| |
| if (!operand_equal_p (TREE_OPERAND (ref1, 1), |
| cheap_array_ref_low_bound (ref1), 0)) |
| return 0; |
| } |
| for (; narray_refs2 > narray_refs1; narray_refs2--) |
| { |
| ref2 = component_refs2.pop (); |
| ntbaa2--; |
| if (!operand_equal_p (TREE_OPERAND (ref2, 1), |
| cheap_array_ref_low_bound (ref2), 0)) |
| return 0; |
| } |
| /* Try to disambiguate matched arrays. */ |
| for (unsigned int i = 0; i < narray_refs1; i++) |
| { |
| int cmp = nonoverlapping_array_refs_p (component_refs1.pop (), |
| component_refs2.pop ()); |
| ntbaa1--; |
| ntbaa2--; |
| if (cmp == 1 && !partial_overlap) |
| { |
| ++alias_stats |
| .nonoverlapping_refs_since_match_p_no_alias; |
| return 1; |
| } |
| if (cmp == -1) |
| { |
| seen_unmatched_ref_p = true; |
| /* We can not maintain the invariant that bases are either |
| same or completely disjoint. However we can still recover |
| from type based alias analysis if we reach references to |
| same sizes. We do not attempt to match array sizes, so |
| just finish array walking and look for component refs. */ |
| if (ntbaa1 < 0 || ntbaa2 < 0) |
| { |
| ++alias_stats.nonoverlapping_refs_since_match_p_may_alias; |
| return -1; |
| } |
| for (i++; i < narray_refs1; i++) |
| { |
| component_refs1.pop (); |
| component_refs2.pop (); |
| ntbaa1--; |
| ntbaa2--; |
| } |
| break; |
| } |
| partial_overlap = false; |
| } |
| } |
| |
| /* Next look for component_refs. */ |
| do |
| { |
| if (component_refs1.is_empty ()) |
| { |
| ++alias_stats |
| .nonoverlapping_refs_since_match_p_must_overlap; |
| return 0; |
| } |
| ref1 = component_refs1.pop (); |
| ntbaa1--; |
| if (TREE_CODE (ref1) != COMPONENT_REF) |
| { |
| seen_unmatched_ref_p = true; |
| if (ntbaa1 < 0 || ntbaa2 < 0) |
| { |
| ++alias_stats.nonoverlapping_refs_since_match_p_may_alias; |
| return -1; |
| } |
| } |
| } |
| while (!RECORD_OR_UNION_TYPE_P (TREE_TYPE (TREE_OPERAND (ref1, 0)))); |
| |
| do |
| { |
| if (component_refs2.is_empty ()) |
| { |
| ++alias_stats |
| .nonoverlapping_refs_since_match_p_must_overlap; |
| return 0; |
| } |
| ref2 = component_refs2.pop (); |
| ntbaa2--; |
| if (TREE_CODE (ref2) != COMPONENT_REF) |
| { |
| if (ntbaa1 < 0 || ntbaa2 < 0) |
| { |
| ++alias_stats.nonoverlapping_refs_since_match_p_may_alias; |
| return -1; |
| } |
| seen_unmatched_ref_p = true; |
| } |
| } |
| while (!RECORD_OR_UNION_TYPE_P (TREE_TYPE (TREE_OPERAND (ref2, 0)))); |
| |
| /* BIT_FIELD_REF and VIEW_CONVERT_EXPR are taken off the vectors |
| earlier. */ |
| gcc_checking_assert (TREE_CODE (ref1) == COMPONENT_REF |
| && TREE_CODE (ref2) == COMPONENT_REF); |
| |
| tree field1 = TREE_OPERAND (ref1, 1); |
| tree field2 = TREE_OPERAND (ref2, 1); |
| |
| /* ??? We cannot simply use the type of operand #0 of the refs here |
| as the Fortran compiler smuggles type punning into COMPONENT_REFs |
| for common blocks instead of using unions like everyone else. */ |
| tree type1 = DECL_CONTEXT (field1); |
| tree type2 = DECL_CONTEXT (field2); |
| |
| partial_overlap = false; |
| |
| /* If we skipped array refs on type of different sizes, we can |
| no longer be sure that there are not partial overlaps. */ |
| if (seen_unmatched_ref_p && ntbaa1 >= 0 && ntbaa2 >= 0 |
| && !operand_equal_p (TYPE_SIZE (type1), TYPE_SIZE (type2), 0)) |
| { |
| ++alias_stats |
| .nonoverlapping_refs_since_match_p_may_alias; |
| return -1; |
| } |
| |
| int cmp = nonoverlapping_component_refs_p_1 (field1, field2); |
| if (cmp == -1) |
| { |
| ++alias_stats |
| .nonoverlapping_refs_since_match_p_may_alias; |
| return -1; |
| } |
| else if (cmp == 1) |
| { |
| ++alias_stats |
| .nonoverlapping_refs_since_match_p_no_alias; |
| return 1; |
| } |
| } |
| |
| ++alias_stats.nonoverlapping_refs_since_match_p_must_overlap; |
| return 0; |
| } |
| |
| /* Return TYPE_UID which can be used to match record types we consider |
| same for TBAA purposes. */ |
| |
| static inline int |
| ncr_type_uid (const_tree field) |
| { |
| /* ??? We cannot simply use the type of operand #0 of the refs here |
| as the Fortran compiler smuggles type punning into COMPONENT_REFs |
| for common blocks instead of using unions like everyone else. */ |
| tree type = DECL_FIELD_CONTEXT (field); |
| /* With LTO types considered same_type_for_tbaa_p |
| from different translation unit may not have same |
| main variant. They however have same TYPE_CANONICAL. */ |
| if (TYPE_CANONICAL (type)) |
| return TYPE_UID (TYPE_CANONICAL (type)); |
| return TYPE_UID (type); |
| } |
| |
| /* qsort compare function to sort FIELD_DECLs after their |
| DECL_FIELD_CONTEXT TYPE_UID. */ |
| |
| static inline int |
| ncr_compar (const void *field1_, const void *field2_) |
| { |
| const_tree field1 = *(const_tree *) const_cast <void *>(field1_); |
| const_tree field2 = *(const_tree *) const_cast <void *>(field2_); |
| unsigned int uid1 = ncr_type_uid (field1); |
| unsigned int uid2 = ncr_type_uid (field2); |
| |
| if (uid1 < uid2) |
| return -1; |
| else if (uid1 > uid2) |
| return 1; |
| return 0; |
| } |
| |
| /* Return true if we can determine that the fields referenced cannot |
| overlap for any pair of objects. This relies on TBAA. */ |
| |
| static bool |
| nonoverlapping_component_refs_p (const_tree x, const_tree y) |
| { |
| /* Early return if we have nothing to do. |
| |
| Do not consider this as may-alias for stats - it is more useful |
| to have information how many disambiguations happened provided that |
| the query was meaningful. */ |
| if (!flag_strict_aliasing |
| || !x || !y |
| || !handled_component_p (x) |
| || !handled_component_p (y)) |
| return false; |
| |
| auto_vec<const_tree, 16> fieldsx; |
| while (handled_component_p (x)) |
| { |
| if (TREE_CODE (x) == COMPONENT_REF) |
| { |
| tree field = TREE_OPERAND (x, 1); |
| tree type = DECL_FIELD_CONTEXT (field); |
| if (TREE_CODE (type) == RECORD_TYPE) |
| fieldsx.safe_push (field); |
| } |
| else if (ends_tbaa_access_path_p (x)) |
| fieldsx.truncate (0); |
| x = TREE_OPERAND (x, 0); |
| } |
| if (fieldsx.length () == 0) |
| return false; |
| auto_vec<const_tree, 16> fieldsy; |
| while (handled_component_p (y)) |
| { |
| if (TREE_CODE (y) == COMPONENT_REF) |
| { |
| tree field = TREE_OPERAND (y, 1); |
| tree type = DECL_FIELD_CONTEXT (field); |
| if (TREE_CODE (type) == RECORD_TYPE) |
| fieldsy.safe_push (TREE_OPERAND (y, 1)); |
| } |
| else if (ends_tbaa_access_path_p (y)) |
| fieldsy.truncate (0); |
| y = TREE_OPERAND (y, 0); |
| } |
| if (fieldsy.length () == 0) |
| { |
| ++alias_stats.nonoverlapping_component_refs_p_may_alias; |
| return false; |
| } |
| |
| /* Most common case first. */ |
| if (fieldsx.length () == 1 |
| && fieldsy.length () == 1) |
| { |
| if (same_type_for_tbaa (DECL_FIELD_CONTEXT (fieldsx[0]), |
| DECL_FIELD_CONTEXT (fieldsy[0])) == 1 |
| && nonoverlapping_component_refs_p_1 (fieldsx[0], fieldsy[0]) == 1) |
| { |
| ++alias_stats.nonoverlapping_component_refs_p_no_alias; |
| return true; |
| } |
| else |
| { |
| ++alias_stats.nonoverlapping_component_refs_p_may_alias; |
| return false; |
| } |
| } |
| |
| if (fieldsx.length () == 2) |
| { |
| if (ncr_compar (&fieldsx[0], &fieldsx[1]) == 1) |
| std::swap (fieldsx[0], fieldsx[1]); |
| } |
| else |
| fieldsx.qsort (ncr_compar); |
| |
| if (fieldsy.length () == 2) |
| { |
| if (ncr_compar (&fieldsy[0], &fieldsy[1]) == 1) |
| std::swap (fieldsy[0], fieldsy[1]); |
| } |
| else |
| fieldsy.qsort (ncr_compar); |
| |
| unsigned i = 0, j = 0; |
| do |
| { |
| const_tree fieldx = fieldsx[i]; |
| const_tree fieldy = fieldsy[j]; |
| |
| /* We're left with accessing different fields of a structure, |
| no possible overlap. */ |
| if (same_type_for_tbaa (DECL_FIELD_CONTEXT (fieldx), |
| DECL_FIELD_CONTEXT (fieldy)) == 1 |
| && nonoverlapping_component_refs_p_1 (fieldx, fieldy) == 1) |
| { |
| ++alias_stats.nonoverlapping_component_refs_p_no_alias; |
| return true; |
| } |
| |
| if (ncr_type_uid (fieldx) < ncr_type_uid (fieldy)) |
| { |
| i++; |
| if (i == fieldsx.length ()) |
| break; |
| } |
| else |
| { |
| j++; |
| if (j == fieldsy.length ()) |
| break; |
| } |
| } |
| while (1); |
| |
| ++alias_stats.nonoverlapping_component_refs_p_may_alias; |
| return false; |
| } |
| |
| |
| /* Return true if two memory references based on the variables BASE1 |
| and BASE2 constrained to [OFFSET1, OFFSET1 + MAX_SIZE1) and |
| [OFFSET2, OFFSET2 + MAX_SIZE2) may alias. REF1 and REF2 |
| if non-NULL are the complete memory reference trees. */ |
| |
| static bool |
| decl_refs_may_alias_p (tree ref1, tree base1, |
| poly_int64 offset1, poly_int64 max_size1, |
| poly_int64 size1, |
| tree ref2, tree base2, |
| poly_int64 offset2, poly_int64 max_size2, |
| poly_int64 size2) |
| { |
| gcc_checking_assert (DECL_P (base1) && DECL_P (base2)); |
| |
| /* If both references are based on different variables, they cannot alias. */ |
| if (compare_base_decls (base1, base2) == 0) |
| return false; |
| |
| /* If both references are based on the same variable, they cannot alias if |
| the accesses do not overlap. */ |
| if (!ranges_maybe_overlap_p (offset1, max_size1, offset2, max_size2)) |
| return false; |
| |
| /* If there is must alias, there is no use disambiguating further. */ |
| if (known_eq (size1, max_size1) && known_eq (size2, max_size2)) |
| return true; |
| |
| /* For components with variable position, the above test isn't sufficient, |
| so we disambiguate component references manually. */ |
| if (ref1 && ref2 |
| && handled_component_p (ref1) && handled_component_p (ref2) |
| && nonoverlapping_refs_since_match_p (NULL, ref1, NULL, ref2, false) == 1) |
| return false; |
| |
| return true; |
| } |
| |
| /* Return true if access with BASE is view converted. |
| Base must not be stripped from inner MEM_REF (&decl) |
| which is done by ao_ref_base and thus one extra walk |
| of handled components is needed. */ |
| |
| static bool |
| view_converted_memref_p (tree base) |
| { |
| if (TREE_CODE (base) != MEM_REF && TREE_CODE (base) != TARGET_MEM_REF) |
| return false; |
| return same_type_for_tbaa (TREE_TYPE (base), |
| TREE_TYPE (TREE_OPERAND (base, 1))) != 1; |
| } |
| |
| /* Return true if an indirect reference based on *PTR1 constrained |
| to [OFFSET1, OFFSET1 + MAX_SIZE1) may alias a variable based on BASE2 |
| constrained to [OFFSET2, OFFSET2 + MAX_SIZE2). *PTR1 and BASE2 have |
| the alias sets BASE1_ALIAS_SET and BASE2_ALIAS_SET which can be -1 |
| in which case they are computed on-demand. REF1 and REF2 |
| if non-NULL are the complete memory reference trees. */ |
| |
| static bool |
| indirect_ref_may_alias_decl_p (tree ref1 ATTRIBUTE_UNUSED, tree base1, |
| poly_int64 offset1, poly_int64 max_size1, |
| poly_int64 size1, |
| alias_set_type ref1_alias_set, |
| alias_set_type base1_alias_set, |
| tree ref2 ATTRIBUTE_UNUSED, tree base2, |
| poly_int64 offset2, poly_int64 max_size2, |
| poly_int64 size2, |
| alias_set_type ref2_alias_set, |
| alias_set_type base2_alias_set, bool tbaa_p) |
| { |
| tree ptr1; |
| tree ptrtype1, dbase2; |
| |
| gcc_checking_assert ((TREE_CODE (base1) == MEM_REF |
| || TREE_CODE (base1) == TARGET_MEM_REF) |
| && DECL_P (base2)); |
| |
| ptr1 = TREE_OPERAND (base1, 0); |
| poly_offset_int moff = mem_ref_offset (base1) << LOG2_BITS_PER_UNIT; |
| |
| /* If only one reference is based on a variable, they cannot alias if |
| the pointer access is beyond the extent of the variable access. |
| (the pointer base cannot validly point to an offset less than zero |
| of the variable). |
| ??? IVOPTs creates bases that do not honor this restriction, |
| so do not apply this optimization for TARGET_MEM_REFs. */ |
| if (TREE_CODE (base1) != TARGET_MEM_REF |
| && !ranges_maybe_overlap_p (offset1 + moff, -1, offset2, max_size2)) |
| return false; |
| /* They also cannot alias if the pointer may not point to the decl. */ |
| if (!ptr_deref_may_alias_decl_p (ptr1, base2)) |
| return false; |
| |
| /* Disambiguations that rely on strict aliasing rules follow. */ |
| if (!flag_strict_aliasing || !tbaa_p) |
| return true; |
| |
| /* If the alias set for a pointer access is zero all bets are off. */ |
| if (base1_alias_set == 0 || base2_alias_set == 0) |
| return true; |
| |
| /* When we are trying to disambiguate an access with a pointer dereference |
| as base versus one with a decl as base we can use both the size |
| of the decl and its dynamic type for extra disambiguation. |
| ??? We do not know anything about the dynamic type of the decl |
| other than that its alias-set contains base2_alias_set as a subset |
| which does not help us here. */ |
| /* As we know nothing useful about the dynamic type of the decl just |
| use the usual conflict check rather than a subset test. |
| ??? We could introduce -fvery-strict-aliasing when the language |
| does not allow decls to have a dynamic type that differs from their |
| static type. Then we can check |
| !alias_set_subset_of (base1_alias_set, base2_alias_set) instead. */ |
| if (base1_alias_set != base2_alias_set |
| && !alias_sets_conflict_p (base1_alias_set, base2_alias_set)) |
| return false; |
| |
| ptrtype1 = TREE_TYPE (TREE_OPERAND (base1, 1)); |
| |
| /* If the size of the access relevant for TBAA through the pointer |
| is bigger than the size of the decl we can't possibly access the |
| decl via that pointer. */ |
| if (/* ??? This in turn may run afoul when a decl of type T which is |
| a member of union type U is accessed through a pointer to |
| type U and sizeof T is smaller than sizeof U. */ |
| TREE_CODE (TREE_TYPE (ptrtype1)) != UNION_TYPE |
| && TREE_CODE (TREE_TYPE (ptrtype1)) != QUAL_UNION_TYPE |
| && compare_sizes (DECL_SIZE (base2), |
| TYPE_SIZE (TREE_TYPE (ptrtype1))) < 0) |
| return false; |
| |
| if (!ref2) |
| return true; |
| |
| /* If the decl is accessed via a MEM_REF, reconstruct the base |
| we can use for TBAA and an appropriately adjusted offset. */ |
| dbase2 = ref2; |
| while (handled_component_p (dbase2)) |
| dbase2 = TREE_OPERAND (dbase2, 0); |
| poly_int64 doffset1 = offset1; |
| poly_offset_int doffset2 = offset2; |
| if (TREE_CODE (dbase2) == MEM_REF |
| || TREE_CODE (dbase2) == TARGET_MEM_REF) |
| { |
| doffset2 -= mem_ref_offset (dbase2) << LOG2_BITS_PER_UNIT; |
| tree ptrtype2 = TREE_TYPE (TREE_OPERAND (dbase2, 1)); |
| /* If second reference is view-converted, give up now. */ |
| if (same_type_for_tbaa (TREE_TYPE (dbase2), TREE_TYPE (ptrtype2)) != 1) |
| return true; |
| } |
| |
| /* If first reference is view-converted, give up now. */ |
| if (same_type_for_tbaa (TREE_TYPE (base1), TREE_TYPE (ptrtype1)) != 1) |
| return true; |
| |
| /* If both references are through the same type, they do not alias |
| if the accesses do not overlap. This does extra disambiguation |
| for mixed/pointer accesses but requires strict aliasing. |
| For MEM_REFs we require that the component-ref offset we computed |
| is relative to the start of the type which we ensure by |
| comparing rvalue and access type and disregarding the constant |
| pointer offset. |
| |
| But avoid treating variable length arrays as "objects", instead assume they |
| can overlap by an exact multiple of their element size. |
| See gcc.dg/torture/alias-2.c. */ |
| if (((TREE_CODE (base1) != TARGET_MEM_REF |
| || (!TMR_INDEX (base1) && !TMR_INDEX2 (base1))) |
| && (TREE_CODE (dbase2) != TARGET_MEM_REF |
| || (!TMR_INDEX (dbase2) && !TMR_INDEX2 (dbase2)))) |
| && same_type_for_tbaa (TREE_TYPE (base1), TREE_TYPE (dbase2)) == 1) |
| { |
| bool partial_overlap = (TREE_CODE (TREE_TYPE (base1)) == ARRAY_TYPE |
| && (TYPE_SIZE (TREE_TYPE (base1)) |
| && TREE_CODE (TYPE_SIZE (TREE_TYPE (base1))) |
| != INTEGER_CST)); |
| if (!partial_overlap |
| && !ranges_maybe_overlap_p (doffset1, max_size1, doffset2, max_size2)) |
| return false; |
| if (!ref1 || !ref2 |
| /* If there is must alias, there is no use disambiguating further. */ |
| || (!partial_overlap |
| && known_eq (size1, max_size1) && known_eq (size2, max_size2))) |
| return true; |
| int res = nonoverlapping_refs_since_match_p (base1, ref1, base2, ref2, |
| partial_overlap); |
| if (res == -1) |
| return !nonoverlapping_component_refs_p (ref1, ref2); |
| return !res; |
| } |
| |
| /* Do access-path based disambiguation. */ |
| if (ref1 && ref2 |
| && (handled_component_p (ref1) || handled_component_p (ref2))) |
| return aliasing_component_refs_p (ref1, |
| ref1_alias_set, base1_alias_set, |
| offset1, max_size1, |
| ref2, |
| ref2_alias_set, base2_alias_set, |
| offset2, max_size2); |
| |
| return true; |
| } |
| |
| /* Return true if two indirect references based on *PTR1 |
| and *PTR2 constrained to [OFFSET1, OFFSET1 + MAX_SIZE1) and |
| [OFFSET2, OFFSET2 + MAX_SIZE2) may alias. *PTR1 and *PTR2 have |
| the alias sets BASE1_ALIAS_SET and BASE2_ALIAS_SET which can be -1 |
| in which case they are computed on-demand. REF1 and REF2 |
| if non-NULL are the complete memory reference trees. */ |
| |
| static bool |
| indirect_refs_may_alias_p (tree ref1 ATTRIBUTE_UNUSED, tree base1, |
| poly_int64 offset1, poly_int64 max_size1, |
| poly_int64 size1, |
| alias_set_type ref1_alias_set, |
| alias_set_type base1_alias_set, |
| tree ref2 ATTRIBUTE_UNUSED, tree base2, |
| poly_int64 offset2, poly_int64 max_size2, |
| poly_int64 size2, |
| alias_set_type ref2_alias_set, |
| alias_set_type base2_alias_set, bool tbaa_p) |
| { |
| tree ptr1; |
| tree ptr2; |
| tree ptrtype1, ptrtype2; |
| |
| gcc_checking_assert ((TREE_CODE (base1) == MEM_REF |
| || TREE_CODE (base1) == TARGET_MEM_REF) |
| && (TREE_CODE (base2) == MEM_REF |
| || TREE_CODE (base2) == TARGET_MEM_REF)); |
| |
| ptr1 = TREE_OPERAND (base1, 0); |
| ptr2 = TREE_OPERAND (base2, 0); |
| |
| /* If both bases are based on pointers they cannot alias if they may not |
| point to the same memory object or if they point to the same object |
| and the accesses do not overlap. */ |
| if ((!cfun || gimple_in_ssa_p (cfun)) |
| && operand_equal_p (ptr1, ptr2, 0) |
| && (((TREE_CODE (base1) != TARGET_MEM_REF |
| || (!TMR_INDEX (base1) && !TMR_INDEX2 (base1))) |
| && (TREE_CODE (base2) != TARGET_MEM_REF |
| || (!TMR_INDEX (base2) && !TMR_INDEX2 (base2)))) |
| || (TREE_CODE (base1) == TARGET_MEM_REF |
| && TREE_CODE (base2) == TARGET_MEM_REF |
| && (TMR_STEP (base1) == TMR_STEP (base2) |
| || (TMR_STEP (base1) && TMR_STEP (base2) |
| && operand_equal_p (TMR_STEP (base1), |
| TMR_STEP (base2), 0))) |
| && (TMR_INDEX (base1) == TMR_INDEX (base2) |
| || (TMR_INDEX (base1) && TMR_INDEX (base2) |
| && operand_equal_p (TMR_INDEX (base1), |
| TMR_INDEX (base2), 0))) |
| && (TMR_INDEX2 (base1) == TMR_INDEX2 (base2) |
| || (TMR_INDEX2 (base1) && TMR_INDEX2 (base2) |
| && operand_equal_p (TMR_INDEX2 (base1), |
| TMR_INDEX2 (base2), 0)))))) |
| { |
| poly_offset_int moff1 = mem_ref_offset (base1) << LOG2_BITS_PER_UNIT; |
| poly_offset_int moff2 = mem_ref_offset (base2) << LOG2_BITS_PER_UNIT; |
| if (!ranges_maybe_overlap_p (offset1 + moff1, max_size1, |
| offset2 + moff2, max_size2)) |
| return false; |
| /* If there is must alias, there is no use disambiguating further. */ |
| if (known_eq (size1, max_size1) && known_eq (size2, max_size2)) |
| return true; |
| if (ref1 && ref2) |
| { |
| int res = nonoverlapping_refs_since_match_p (NULL, ref1, NULL, ref2, |
| false); |
| if (res != -1) |
| return !res; |
| } |
| } |
| if (!ptr_derefs_may_alias_p (ptr1, ptr2)) |
| return false; |
| |
| /* Disambiguations that rely on strict aliasing rules follow. */ |
| if (!flag_strict_aliasing || !tbaa_p) |
| return true; |
| |
| ptrtype1 = TREE_TYPE (TREE_OPERAND (base1, 1)); |
| ptrtype2 = TREE_TYPE (TREE_OPERAND (base2, 1)); |
| |
| /* If the alias set for a pointer access is zero all bets are off. */ |
| if (base1_alias_set == 0 |
| || base2_alias_set == 0) |
| return true; |
| |
| /* Do type-based disambiguation. */ |
| if (base1_alias_set != base2_alias_set |
| && !alias_sets_conflict_p (base1_alias_set, base2_alias_set)) |
| return false; |
| |
| /* If either reference is view-converted, give up now. */ |
| if (same_type_for_tbaa (TREE_TYPE (base1), TREE_TYPE (ptrtype1)) != 1 |
| || same_type_for_tbaa (TREE_TYPE (base2), TREE_TYPE (ptrtype2)) != 1) |
| return true; |
| |
| /* If both references are through the same type, they do not alias |
| if the accesses do not overlap. This does extra disambiguation |
| for mixed/pointer accesses but requires strict aliasing. */ |
| if ((TREE_CODE (base1) != TARGET_MEM_REF |
| || (!TMR_INDEX (base1) && !TMR_INDEX2 (base1))) |
| && (TREE_CODE (base2) != TARGET_MEM_REF |
| || (!TMR_INDEX (base2) && !TMR_INDEX2 (base2))) |
| && same_type_for_tbaa (TREE_TYPE (ptrtype1), |
| TREE_TYPE (ptrtype2)) == 1) |
| { |
| /* But avoid treating arrays as "objects", instead assume they |
| can overlap by an exact multiple of their element size. |
| See gcc.dg/torture/alias-2.c. */ |
| bool partial_overlap = TREE_CODE (TREE_TYPE (ptrtype1)) == ARRAY_TYPE; |
| |
| if (!partial_overlap |
| && !ranges_maybe_overlap_p (offset1, max_size1, offset2, max_size2)) |
| return false; |
| if (!ref1 || !ref2 |
| || (!partial_overlap |
| && known_eq (size1, max_size1) && known_eq (size2, max_size2))) |
| return true; |
| int res = nonoverlapping_refs_since_match_p (base1, ref1, base2, ref2, |
| partial_overlap); |
| if (res == -1) |
| return !nonoverlapping_component_refs_p (ref1, ref2); |
| return !res; |
| } |
| |
| /* Do access-path based disambiguation. */ |
| if (ref1 && ref2 |
| && (handled_component_p (ref1) || handled_component_p (ref2))) |
| return aliasing_component_refs_p (ref1, |
| ref1_alias_set, base1_alias_set, |
| offset1, max_size1, |
| ref2, |
| ref2_alias_set, base2_alias_set, |
| offset2, max_size2); |
| |
| return true; |
| } |
| |
| /* Return true, if the two memory references REF1 and REF2 may alias. */ |
| |
| static bool |
| refs_may_alias_p_2 (ao_ref *ref1, ao_ref *ref2, bool tbaa_p) |
| { |
| tree base1, base2; |
| poly_int64 offset1 = 0, offset2 = 0; |
| poly_int64 max_size1 = -1, max_size2 = -1; |
| bool var1_p, var2_p, ind1_p, ind2_p; |
| |
| gcc_checking_assert ((!ref1->ref |
| || TREE_CODE (ref1->ref) == SSA_NAME |
| || DECL_P (ref1->ref) |
| || TREE_CODE (ref1->ref) == STRING_CST |
| || handled_component_p (ref1->ref) |
| || TREE_CODE (ref1->ref) == MEM_REF |
| || TREE_CODE (ref1->ref) == TARGET_MEM_REF) |
| && (!ref2->ref |
| || TREE_CODE (ref2->ref) == SSA_NAME |
| || DECL_P (ref2->ref) |
| || TREE_CODE (ref2->ref) == STRING_CST |
| || handled_component_p (ref2->ref) |
| || TREE_CODE (ref2->ref) == MEM_REF |
| || TREE_CODE (ref2->ref) == TARGET_MEM_REF)); |
| |
| /* Decompose the references into their base objects and the access. */ |
| base1 = ao_ref_base (ref1); |
| offset1 = ref1->offset; |
| max_size1 = ref1->max_size; |
| base2 = ao_ref_base (ref2); |
| offset2 = ref2->offset; |
| max_size2 = ref2->max_size; |
| |
| /* We can end up with registers or constants as bases for example from |
| *D.1663_44 = VIEW_CONVERT_EXPR<struct DB_LSN>(__tmp$B0F64_59); |
| which is seen as a struct copy. */ |
| if (TREE_CODE (base1) == SSA_NAME |
| || TREE_CODE (base1) == CONST_DECL |
| || TREE_CODE (base1) == CONSTRUCTOR |
| || TREE_CODE (base1) == ADDR_EXPR |
| || CONSTANT_CLASS_P (base1) |
| || TREE_CODE (base2) == SSA_NAME |
| || TREE_CODE (base2) == CONST_DECL |
| || TREE_CODE (base2) == CONSTRUCTOR |
| || TREE_CODE (base2) == ADDR_EXPR |
| || CONSTANT_CLASS_P (base2)) |
| return false; |
| |
| /* We can end up referring to code via function and label decls. |
| As we likely do not properly track code aliases conservatively |
| bail out. */ |
| if (TREE_CODE (base1) == FUNCTION_DECL |
| || TREE_CODE (base1) == LABEL_DECL |
| || TREE_CODE (base2) == FUNCTION_DECL |
| || TREE_CODE (base2) == LABEL_DECL) |
| return true; |
| |
| /* Two volatile accesses always conflict. */ |
| if (ref1->volatile_p |
| && ref2->volatile_p) |
| return true; |
| |
| /* Defer to simple offset based disambiguation if we have |
| references based on two decls. Do this before defering to |
| TBAA to handle must-alias cases in conformance with the |
| GCC extension of allowing type-punning through unions. */ |
| var1_p = DECL_P (base1); |
| var2_p = DECL_P (base2); |
| if (var1_p && var2_p) |
| return decl_refs_may_alias_p (ref1->ref, base1, offset1, max_size1, |
| ref1->size, |
| ref2->ref, base2, offset2, max_size2, |
| ref2->size); |
| |
| /* Handle restrict based accesses. |
| ??? ao_ref_base strips inner MEM_REF [&decl], recover from that |
| here. */ |
| tree rbase1 = base1; |
| tree rbase2 = base2; |
| if (var1_p) |
| { |
| rbase1 = ref1->ref; |
| if (rbase1) |
| while (handled_component_p (rbase1)) |
| rbase1 = TREE_OPERAND (rbase1, 0); |
| } |
| if (var2_p) |
| { |
| rbase2 = ref2->ref; |
| if (rbase2) |
| while (handled_component_p (rbase2)) |
| rbase2 = TREE_OPERAND (rbase2, 0); |
| } |
| if (rbase1 && rbase2 |
| && (TREE_CODE (base1) == MEM_REF || TREE_CODE (base1) == TARGET_MEM_REF) |
| && (TREE_CODE (base2) == MEM_REF || TREE_CODE (base2) == TARGET_MEM_REF) |
| /* If the accesses are in the same restrict clique... */ |
| && MR_DEPENDENCE_CLIQUE (base1) == MR_DEPENDENCE_CLIQUE (base2) |
| /* But based on different pointers they do not alias. */ |
| && MR_DEPENDENCE_BASE (base1) != MR_DEPENDENCE_BASE (base2)) |
| return false; |
| |
| ind1_p = (TREE_CODE (base1) == MEM_REF |
| || TREE_CODE (base1) == TARGET_MEM_REF); |
| ind2_p = (TREE_CODE (base2) == MEM_REF |
| || TREE_CODE (base2) == TARGET_MEM_REF); |
| |
| /* Canonicalize the pointer-vs-decl case. */ |
| if (ind1_p && var2_p) |
| { |
| std::swap (offset1, offset2); |
| std::swap (max_size1, max_size2); |
| std::swap (base1, base2); |
| std::swap (ref1, ref2); |
| var1_p = true; |
| ind1_p = false; |
| var2_p = false; |
| ind2_p = true; |
| } |
| |
| /* First defer to TBAA if possible. */ |
| if (tbaa_p |
| && flag_strict_aliasing |
| && !alias_sets_conflict_p (ao_ref_alias_set (ref1), |
| ao_ref_alias_set (ref2))) |
| return false; |
| |
| /* If the reference is based on a pointer that points to memory |
| that may not be written to then the other reference cannot possibly |
| clobber it. */ |
| if ((TREE_CODE (TREE_OPERAND (base2, 0)) == SSA_NAME |
| && SSA_NAME_POINTS_TO_READONLY_MEMORY (TREE_OPERAND (base2, 0))) |
| || (ind1_p |
| && TREE_CODE (TREE_OPERAND (base1, 0)) == SSA_NAME |
| && SSA_NAME_POINTS_TO_READONLY_MEMORY (TREE_OPERAND (base1, 0)))) |
| return false; |
| |
| /* Dispatch to the pointer-vs-decl or pointer-vs-pointer disambiguators. */ |
| if (var1_p && ind2_p) |
| return indirect_ref_may_alias_decl_p (ref2->ref, base2, |
| offset2, max_size2, ref2->size, |
| ao_ref_alias_set (ref2), |
| ao_ref_base_alias_set (ref2), |
| ref1->ref, base1, |
| offset1, max_size1, ref1->size, |
| ao_ref_alias_set (ref1), |
| ao_ref_base_alias_set (ref1), |
| tbaa_p); |
| else if (ind1_p && ind2_p) |
| return indirect_refs_may_alias_p (ref1->ref, base1, |
| offset1, max_size1, ref1->size, |
| ao_ref_alias_set (ref1), |
| ao_ref_base_alias_set (ref1), |
| ref2->ref, base2, |
| offset2, max_size2, ref2->size, |
| ao_ref_alias_set (ref2), |
| ao_ref_base_alias_set (ref2), |
| tbaa_p); |
| |
| gcc_unreachable (); |
| } |
| |
| /* Return true, if the two memory references REF1 and REF2 may alias |
| and update statistics. */ |
| |
| bool |
| refs_may_alias_p_1 (ao_ref *ref1, ao_ref *ref2, bool tbaa_p) |
| { |
| bool res = refs_may_alias_p_2 (ref1, ref2, tbaa_p); |
| if (res) |
| ++alias_stats.refs_may_alias_p_may_alias; |
| else |
| ++alias_stats.refs_may_alias_p_no_alias; |
| return res; |
| } |
| |
| static bool |
| refs_may_alias_p (tree ref1, ao_ref *ref2, bool tbaa_p) |
| { |
| ao_ref r1; |
| ao_ref_init (&r1, ref1); |
| return refs_may_alias_p_1 (&r1, ref2, tbaa_p); |
| } |
| |
| bool |
| refs_may_alias_p (tree ref1, tree ref2, bool tbaa_p) |
| { |
| ao_ref r1, r2; |
| ao_ref_init (&r1, ref1); |
| ao_ref_init (&r2, ref2); |
| return refs_may_alias_p_1 (&r1, &r2, tbaa_p); |
| } |
| |
| /* Returns true if there is a anti-dependence for the STORE that |
| executes after the LOAD. */ |
| |
| bool |
| refs_anti_dependent_p (tree load, tree store) |
| { |
| ao_ref r1, r2; |
| ao_ref_init (&r1, load); |
| ao_ref_init (&r2, store); |
| return refs_may_alias_p_1 (&r1, &r2, false); |
| } |
| |
| /* Returns true if there is a output dependence for the stores |
| STORE1 and STORE2. */ |
| |
| bool |
| refs_output_dependent_p (tree store1, tree store2) |
| { |
| ao_ref r1, r2; |
| ao_ref_init (&r1, store1); |
| ao_ref_init (&r2, store2); |
| return refs_may_alias_p_1 (&r1, &r2, false); |
| } |
| |
| /* Returns true if and only if REF may alias any access stored in TT. |
| IF TBAA_P is true, use TBAA oracle. */ |
| |
| static bool |
| modref_may_conflict (const gimple *stmt, |
| modref_tree <alias_set_type> *tt, ao_ref *ref, bool tbaa_p) |
| { |
| alias_set_type base_set, ref_set; |
| modref_base_node <alias_set_type> *base_node; |
| modref_ref_node <alias_set_type> *ref_node; |
| size_t i, j, k; |
| |
| if (tt->every_base) |
| return true; |
| |
| if (!dbg_cnt (ipa_mod_ref)) |
| return true; |
| |
| base_set = ao_ref_base_alias_set (ref); |
| |
| ref_set = ao_ref_alias_set (ref); |
| |
| int num_tests = 0, max_tests = param_modref_max_tests; |
| FOR_EACH_VEC_SAFE_ELT (tt->bases, i, base_node) |
| { |
| if (tbaa_p && flag_strict_aliasing) |
| { |
| if (num_tests >= max_tests) |
| return true; |
| alias_stats.modref_tests++; |
| if (!alias_sets_conflict_p (base_set, base_node->base)) |
| continue; |
| num_tests++; |
| } |
| |
| if (base_node->every_ref) |
| return true; |
| |
| FOR_EACH_VEC_SAFE_ELT (base_node->refs, j, ref_node) |
| { |
| /* Do not repeat same test as before. */ |
| if ((ref_set != base_set || base_node->base != ref_node->ref) |
| && tbaa_p && flag_strict_aliasing) |
| { |
| if (num_tests >= max_tests) |
| return true; |
| alias_stats.modref_tests++; |
| if (!alias_sets_conflict_p (ref_set, ref_node->ref)) |
| continue; |
| num_tests++; |
| } |
| |
| /* TBAA checks did not disambiguate, try to use base pointer, for |
| that we however need to have ref->ref or ref->base. */ |
| if (ref_node->every_access || (!ref->ref && !ref->base)) |
| return true; |
| |
| modref_access_node *access_node; |
| FOR_EACH_VEC_SAFE_ELT (ref_node->accesses, k, access_node) |
| { |
| if (num_tests >= max_tests) |
| return true; |
| |
| if (access_node->parm_index == -1 |
| || (unsigned)access_node->parm_index |
| >= gimple_call_num_args (stmt)) |
| return true; |
| |
| alias_stats.modref_baseptr_tests++; |
| |
| tree arg = gimple_call_arg (stmt, access_node->parm_index); |
| |
| if (integer_zerop (arg) && flag_delete_null_pointer_checks) |
| continue; |
| |
| if (!POINTER_TYPE_P (TREE_TYPE (arg))) |
| return true; |
| |
| /* ao_ref_init_from_ptr_and_range assumes that memory access |
| starts by the pointed to location. If we did not track the |
| offset it is possible that it starts before the actual |
| pointer. */ |
| if (!access_node->parm_offset_known) |
| { |
| if (ptr_deref_may_alias_ref_p_1 (arg, ref)) |
| return true; |
| } |
| else |
| { |
| ao_ref ref2; |
| poly_offset_int off = (poly_offset_int)access_node->offset |
| + ((poly_offset_int)access_node->parm_offset |
| << LOG2_BITS_PER_UNIT); |
| poly_int64 off2; |
| if (off.to_shwi (&off2)) |
| { |
| ao_ref_init_from_ptr_and_range |
| (&ref2, arg, true, off2, |
| access_node->size, |
| access_node->max_size); |
| ref2.ref_alias_set = ref_set; |
| ref2.base_alias_set = base_set; |
| if (refs_may_alias_p_1 (&ref2, ref, tbaa_p)) |
| return true; |
| } |
| else if (ptr_deref_may_alias_ref_p_1 (arg, ref)) |
| return true; |
| } |
| num_tests++; |
| } |
| } |
| } |
| return false; |
| } |
| |
| /* Check if REF conflicts with call using "fn spec" attribute. |
| If CLOBBER is true we are checking for writes, otherwise check loads. |
| |
| Return 0 if there are no conflicts (except for possible function call |
| argument reads), 1 if there are conflicts and -1 if we can not decide by |
| fn spec. */ |
| |
| static int |
| check_fnspec (gcall *call, ao_ref *ref, bool clobber) |
| { |
| attr_fnspec fnspec = gimple_call_fnspec (call); |
| if (fnspec.known_p ()) |
| { |
| if (clobber |
| ? !fnspec.global_memory_written_p () |
| : !fnspec.global_memory_read_p ()) |
| { |
| for (unsigned int i = 0; i < gimple_call_num_args (call); i++) |
| if (POINTER_TYPE_P (TREE_TYPE (gimple_call_arg (call, i))) |
| && (!fnspec.arg_specified_p (i) |
| || (clobber ? fnspec.arg_maybe_written_p (i) |
| : fnspec.arg_maybe_read_p (i)))) |
| { |
| ao_ref dref; |
| tree size = NULL_TREE; |
| unsigned int size_arg; |
| |
| if (!fnspec.arg_specified_p (i)) |
| ; |
| else if (fnspec.arg_max_access_size_given_by_arg_p |
| (i, &size_arg)) |
| size = gimple_call_arg (call, size_arg); |
| else if (fnspec.arg_access_size_given_by_type_p (i)) |
| { |
| tree callee = gimple_call_fndecl (call); |
| tree t = TYPE_ARG_TYPES (TREE_TYPE (callee)); |
| |
| for (unsigned int p = 0; p < i; p++) |
| t = TREE_CHAIN (t); |
| size = TYPE_SIZE_UNIT (TREE_TYPE (TREE_VALUE (t))); |
| } |
| ao_ref_init_from_ptr_and_size (&dref, |
| gimple_call_arg (call, i), |
| size); |
| if (refs_may_alias_p_1 (&dref, ref, false)) |
| return 1; |
| } |
| if (clobber |
| && fnspec.errno_maybe_written_p () |
| && flag_errno_math |
| && targetm.ref_may_alias_errno (ref)) |
| return 1; |
| return 0; |
| } |
| } |
| |
| /* FIXME: we should handle barriers more consistently, but for now leave the |
| check here. */ |
| if (gimple_call_builtin_p (call, BUILT_IN_NORMAL)) |
| switch (DECL_FUNCTION_CODE (gimple_call_fndecl (call))) |
| { |
| /* __sync_* builtins and some OpenMP builtins act as threading |
| barriers. */ |
| #undef DEF_SYNC_BUILTIN |
| #define DEF_SYNC_BUILTIN(ENUM, NAME, TYPE, ATTRS) case ENUM: |
| #include "sync-builtins.def" |
| #undef DEF_SYNC_BUILTIN |
| case BUILT_IN_GOMP_ATOMIC_START: |
| case BUILT_IN_GOMP_ATOMIC_END: |
| case BUILT_IN_GOMP_BARRIER: |
| case BUILT_IN_GOMP_BARRIER_CANCEL: |
| case BUILT_IN_GOMP_TASKWAIT: |
| case BUILT_IN_GOMP_TASKGROUP_END: |
| case BUILT_IN_GOMP_CRITICAL_START: |
| case BUILT_IN_GOMP_CRITICAL_END: |
| case BUILT_IN_GOMP_CRITICAL_NAME_START: |
| case BUILT_IN_GOMP_CRITICAL_NAME_END: |
| case BUILT_IN_GOMP_LOOP_END: |
| case BUILT_IN_GOMP_LOOP_END_CANCEL: |
| case BUILT_IN_GOMP_ORDERED_START: |
| case BUILT_IN_GOMP_ORDERED_END: |
| case BUILT_IN_GOMP_SECTIONS_END: |
| case BUILT_IN_GOMP_SECTIONS_END_CANCEL: |
| case BUILT_IN_GOMP_SINGLE_COPY_START: |
| case BUILT_IN_GOMP_SINGLE_COPY_END: |
| return 1; |
| |
| default: |
| return -1; |
| } |
| return -1; |
| } |
| |
| /* If the call CALL may use the memory reference REF return true, |
| otherwise return false. */ |
| |
| static bool |
| ref_maybe_used_by_call_p_1 (gcall *call, ao_ref *ref, bool tbaa_p) |
| { |
| tree base, callee; |
| unsigned i; |
| int flags = gimple_call_flags (call); |
| |
| /* Const functions without a static chain do not implicitly use memory. */ |
| if (!gimple_call_chain (call) |
| && (flags & (ECF_CONST|ECF_NOVOPS))) |
| goto process_args; |
| |
| /* A call that is not without side-effects might involve volatile |
| accesses and thus conflicts with all other volatile accesses. */ |
| if (ref->volatile_p) |
| return true; |
| |
| callee = gimple_call_fndecl (call); |
| |
| if (!gimple_call_chain (call) && callee != NULL_TREE) |
| { |
| struct cgraph_node *node = cgraph_node::get (callee); |
| /* We can not safely optimize based on summary of calle if it does |
| not always bind to current def: it is possible that memory load |
| was optimized out earlier and the interposed variant may not be |
| optimized this way. */ |
| if (node && node->binds_to_current_def_p ()) |
| { |
| modref_summary *summary = get_modref_function_summary (node); |
| if (summary) |
| { |
| if (!modref_may_conflict (call, summary->loads, ref, tbaa_p)) |
| { |
| alias_stats.modref_use_no_alias++; |
| if (dump_file && (dump_flags & TDF_DETAILS)) |
| { |
| fprintf (dump_file, |
| "ipa-modref: call stmt "); |
| print_gimple_stmt (dump_file, call, 0); |
| fprintf (dump_file, |
| "ipa-modref: call to %s does not use ", |
| node->dump_name ()); |
| if (!ref->ref && ref->base) |
| { |
| fprintf (dump_file, "base: "); |
| print_generic_expr (dump_file, ref->base); |
| } |
| else if (ref->ref) |
| { |
| fprintf (dump_file, "ref: "); |
| print_generic_expr (dump_file, ref->ref); |
| } |
| fprintf (dump_file, " alias sets: %i->%i\n", |
| ao_ref_base_alias_set (ref), |
| ao_ref_alias_set (ref)); |
| } |
| goto process_args; |
| } |
| alias_stats.modref_use_may_alias++; |
| } |
| } |
| } |
| |
| base = ao_ref_base (ref); |
| if (!base) |
| return true; |
| |
| /* If the reference is based on a decl that is not aliased the call |
| cannot possibly use it. */ |
| if (DECL_P (base) |
| && !may_be_aliased (base) |
| /* But local statics can be used through recursion. */ |
| && !is_global_var (base)) |
| goto process_args; |
| |
| if (int res = check_fnspec (call, ref, false)) |
| { |
| if (res == 1) |
| return true; |
| } |
| else |
| goto process_args; |
| |
| /* Check if base is a global static variable that is not read |
| by the function. */ |
| if (callee != NULL_TREE && VAR_P (base) && TREE_STATIC (base)) |
| { |
| struct cgraph_node *node = cgraph_node::get (callee); |
| bitmap read; |
| int id; |
| |
| /* FIXME: Callee can be an OMP builtin that does not have a call graph |
| node yet. We should enforce that there are nodes for all decls in the |
| IL and remove this check instead. */ |
| if (node |
| && (id = ipa_reference_var_uid (base)) != -1 |
| && (read = ipa_reference_get_read_global (node)) |
| && !bitmap_bit_p (read, id)) |
| goto process_args; |
| } |
| |
| /* Check if the base variable is call-used. */ |
| if (DECL_P (base)) |
| { |
| if (pt_solution_includes (gimple_call_use_set (call), base)) |
| return true; |
| } |
| else if ((TREE_CODE (base) == MEM_REF |
| || TREE_CODE (base) == TARGET_MEM_REF) |
| && TREE_CODE (TREE_OPERAND (base, 0)) == SSA_NAME) |
| { |
| struct ptr_info_def *pi = SSA_NAME_PTR_INFO (TREE_OPERAND (base, 0)); |
| if (!pi) |
| return true; |
| |
| if (pt_solutions_intersect (gimple_call_use_set (call), &pi->pt)) |
| return true; |
| } |
| else |
| return true; |
| |
| /* Inspect call arguments for passed-by-value aliases. */ |
| process_args: |
| for (i = 0; i < gimple_call_num_args (call); ++i) |
| { |
| tree op = gimple_call_arg (call, i); |
| int flags = gimple_call_arg_flags (call, i); |
| |
| if (flags & EAF_UNUSED) |
| continue; |
| |
| if (TREE_CODE (op) == WITH_SIZE_EXPR) |
| op = TREE_OPERAND (op, 0); |
| |
| if (TREE_CODE (op) != SSA_NAME |
| && !is_gimple_min_invariant (op)) |
| { |
| ao_ref r; |
| ao_ref_init (&r, op); |
| if (refs_may_alias_p_1 (&r, ref, tbaa_p)) |
| return true; |
| } |
| } |
| |
| return false; |
| } |
| |
| static bool |
| ref_maybe_used_by_call_p (gcall *call, ao_ref *ref, bool tbaa_p) |
| { |
| bool res; |
| res = ref_maybe_used_by_call_p_1 (call, ref, tbaa_p); |
| if (res) |
| ++alias_stats.ref_maybe_used_by_call_p_may_alias; |
| else |
| ++alias_stats.ref_maybe_used_by_call_p_no_alias; |
| return res; |
| } |
| |
| |
| /* If the statement STMT may use the memory reference REF return |
| true, otherwise return false. */ |
| |
| bool |
| ref_maybe_used_by_stmt_p (gimple *stmt, ao_ref *ref, bool tbaa_p) |
| { |
| if (is_gimple_assign (stmt)) |
| { |
| tree rhs; |
| |
| /* All memory assign statements are single. */ |
| if (!gimple_assign_single_p (stmt)) |
| return false; |
| |
| rhs = gimple_assign_rhs1 (stmt); |
| if (is_gimple_reg (rhs) |
| || is_gimple_min_invariant (rhs) |
| || gimple_assign_rhs_code (stmt) == CONSTRUCTOR) |
| return false; |
| |
| return refs_may_alias_p (rhs, ref, tbaa_p); |
| } |
| else if (is_gimple_call (stmt)) |
| return ref_maybe_used_by_call_p (as_a <gcall *> (stmt), ref, tbaa_p); |
| else if (greturn *return_stmt = dyn_cast <greturn *> (stmt)) |
| { |
| tree retval = gimple_return_retval (return_stmt); |
| if (retval |
| && TREE_CODE (retval) != SSA_NAME |
| && !is_gimple_min_invariant (retval) |
| && refs_may_alias_p (retval, ref, tbaa_p)) |
| return true; |
| /* If ref escapes the function then the return acts as a use. */ |
| tree base = ao_ref_base (ref); |
| if (!base) |
| ; |
| else if (DECL_P (base)) |
| return is_global_var (base); |
| else if (TREE_CODE (base) == MEM_REF |
| || TREE_CODE (base) == TARGET_MEM_REF) |
| return ptr_deref_may_alias_global_p (TREE_OPERAND (base, 0)); |
| return false; |
| } |
| |
| return true; |
| } |
| |
| bool |
| ref_maybe_used_by_stmt_p (gimple *stmt, tree ref, bool tbaa_p) |
| { |
| ao_ref r; |
| ao_ref_init (&r, ref); |
| return ref_maybe_used_by_stmt_p (stmt, &r, tbaa_p); |
| } |
| |
| /* If the call in statement CALL may clobber the memory reference REF |
| return true, otherwise return false. */ |
| |
| bool |
| call_may_clobber_ref_p_1 (gcall *call, ao_ref *ref, bool tbaa_p) |
| { |
| tree base; |
| tree callee; |
| |
| /* If the call is pure or const it cannot clobber anything. */ |
| if (gimple_call_flags (call) |
| & (ECF_PURE|ECF_CONST|ECF_LOOPING_CONST_OR_PURE|ECF_NOVOPS)) |
| return false; |
| if (gimple_call_internal_p (call)) |
| switch (gimple_call_internal_fn (call)) |
| { |
| /* Treat these internal calls like ECF_PURE for aliasing, |
| they don't write to any memory the program should care about. |
| They have important other side-effects, and read memory, |
| so can't be ECF_NOVOPS. */ |
| case IFN_UBSAN_NULL: |
| case IFN_UBSAN_BOUNDS: |
| case IFN_UBSAN_VPTR: |
| case IFN_UBSAN_OBJECT_SIZE: |
| case IFN_UBSAN_PTR: |
| case IFN_ASAN_CHECK: |
| return false; |
| default: |
| break; |
| } |
| |
| callee = gimple_call_fndecl (call); |
| |
| if (callee != NULL_TREE && !ref->volatile_p) |
| { |
| struct cgraph_node *node = cgraph_node::get (callee); |
| if (node) |
| { |
| modref_summary *summary = get_modref_function_summary (node); |
| if (summary) |
| { |
| if (!modref_may_conflict (call, summary->stores, ref, tbaa_p) |
| && (!summary->writes_errno |
| || !targetm.ref_may_alias_errno (ref))) |
| { |
| alias_stats.modref_clobber_no_alias++; |
| if (dump_file && (dump_flags & TDF_DETAILS)) |
| { |
| fprintf (dump_file, |
| "ipa-modref: call stmt "); |
| print_gimple_stmt (dump_file, call, 0); |
| fprintf (dump_file, |
| "ipa-modref: call to %s does not clobber ", |
| node->dump_name ()); |
| if (!ref->ref && ref->base) |
| { |
| fprintf (dump_file, "base: "); |
| print_generic_expr (dump_file, ref->base); |
| } |
| else if (ref->ref) |
| { |
| fprintf (dump_file, "ref: "); |
| print_generic_expr (dump_file, ref->ref); |
| } |
| fprintf (dump_file, " alias sets: %i->%i\n", |
| ao_ref_base_alias_set (ref), |
| ao_ref_alias_set (ref)); |
| } |
| return false; |
| } |
| alias_stats.modref_clobber_may_alias++; |
| } |
| } |
| } |
| |
| base = ao_ref_base (ref); |
| if (!base) |
| return true; |
| |
| if (TREE_CODE (base) == SSA_NAME |
| || CONSTANT_CLASS_P (base)) |
| return false; |
| |
| /* A call that is not without side-effects might involve volatile |
| accesses and thus conflicts with all other volatile accesses. */ |
| if (ref->volatile_p) |
| return true; |
| |
| /* If the reference is based on a decl that is not aliased the call |
| cannot possibly clobber it. */ |
| if (DECL_P (base) |
| && !may_be_aliased (base) |
| /* But local non-readonly statics can be modified through recursion |
| or the call may implement a threading barrier which we must |
| treat as may-def. */ |
| && (TREE_READONLY (base) |
| || !is_global_var (base))) |
| return false; |
| |
| /* If the reference is based on a pointer that points to memory |
| that may not be written to then the call cannot possibly clobber it. */ |
| if ((TREE_CODE (base) == MEM_REF |
| || TREE_CODE (base) == TARGET_MEM_REF) |
| && TREE_CODE (TREE_OPERAND (base, 0)) == SSA_NAME |
| && SSA_NAME_POINTS_TO_READONLY_MEMORY (TREE_OPERAND (base, 0))) |
| return false; |
| |
| if (int res = check_fnspec (call, ref, true)) |
| { |
| if (res == 1) |
| return true; |
| } |
| else |
| return false; |
| |
| /* Check if base is a global static variable that is not written |
| by the function. */ |
| if (callee != NULL_TREE && VAR_P (base) && TREE_STATIC (base)) |
| { |
| struct cgraph_node *node = cgraph_node::get (callee); |
| bitmap written; |
| int id; |
| |
| if (node |
| && (id = ipa_reference_var_uid (base)) != -1 |
| && (written = ipa_reference_get_written_global (node)) |
| && !bitmap_bit_p (written, id)) |
| return false; |
| } |
| |
| /* Check if the base variable is call-clobbered. */ |
| if (DECL_P (base)) |
| return pt_solution_includes (gimple_call_clobber_set (call), base); |
| else if ((TREE_CODE (base) == MEM_REF |
| || TREE_CODE (base) == TARGET_MEM_REF) |
| && TREE_CODE (TREE_OPERAND (base, 0)) == SSA_NAME) |
| { |
| struct ptr_info_def *pi = SSA_NAME_PTR_INFO (TREE_OPERAND (base, 0)); |
| if (!pi) |
| return true; |
| |
| return pt_solutions_intersect (gimple_call_clobber_set (call), &pi->pt); |
| } |
| |
| return true; |
| } |
| |
| /* If the call in statement CALL may clobber the memory reference REF |
| return true, otherwise return false. */ |
| |
| bool |
| call_may_clobber_ref_p (gcall *call, tree ref, bool tbaa_p) |
| { |
| bool res; |
| ao_ref r; |
| ao_ref_init (&r, ref); |
| res = call_may_clobber_ref_p_1 (call, &r, tbaa_p); |
| if (res) |
| ++alias_stats.call_may_clobber_ref_p_may_alias; |
| else |
| ++alias_stats.call_may_clobber_ref_p_no_alias; |
| return res; |
| } |
| |
| |
| /* If the statement STMT may clobber the memory reference REF return true, |
| otherwise return false. */ |
| |
| bool |
| stmt_may_clobber_ref_p_1 (gimple *stmt, ao_ref *ref, bool tbaa_p) |
| { |
| if (is_gimple_call (stmt)) |
| { |
| tree lhs = gimple_call_lhs (stmt); |
| if (lhs |
| && TREE_CODE (lhs) != SSA_NAME) |
| { |
| ao_ref r; |
| ao_ref_init (&r, lhs); |
| if (refs_may_alias_p_1 (ref, &r, tbaa_p)) |
| return true; |
| } |
| |
| return call_may_clobber_ref_p_1 (as_a <gcall *> (stmt), ref, tbaa_p); |
| } |
| else if (gimple_assign_single_p (stmt)) |
| { |
| tree lhs = gimple_assign_lhs (stmt); |
| if (TREE_CODE (lhs) != SSA_NAME) |
| { |
| ao_ref r; |
| ao_ref_init (&r, lhs); |
| return refs_may_alias_p_1 (ref, &r, tbaa_p); |
| } |
| } |
| else if (gimple_code (stmt) == GIMPLE_ASM) |
| return true; |
| |
| return false; |
| } |
| |
| bool |
| stmt_may_clobber_ref_p (gimple *stmt, tree ref, bool tbaa_p) |
| { |
| ao_ref r; |
| ao_ref_init (&r, ref); |
| return stmt_may_clobber_ref_p_1 (stmt, &r, tbaa_p); |
| } |
| |
| /* Return true if store1 and store2 described by corresponding tuples |
| <BASE, OFFSET, SIZE, MAX_SIZE> have the same size and store to the same |
| address. */ |
| |
| static bool |
| same_addr_size_stores_p (tree base1, poly_int64 offset1, poly_int64 size1, |
| poly_int64 max_size1, |
| tree base2, poly_int64 offset2, poly_int64 size2, |
| poly_int64 max_size2) |
| { |
| /* Offsets need to be 0. */ |
| if (maybe_ne (offset1, 0) |
| || maybe_ne (offset2, 0)) |
| return false; |
| |
| bool base1_obj_p = SSA_VAR_P (base1); |
| bool base2_obj_p = SSA_VAR_P (base2); |
| |
| /* We need one object. */ |
| if (base1_obj_p == base2_obj_p) |
| return false; |
| tree obj = base1_obj_p ? base1 : base2; |
| |
| /* And we need one MEM_REF. */ |
| bool base1_memref_p = TREE_CODE (base1) == MEM_REF; |
| bool base2_memref_p = TREE_CODE (base2) == MEM_REF; |
| if (base1_memref_p == base2_memref_p) |
| return false; |
| tree memref = base1_memref_p ? base1 : base2; |
| |
|