| /* Alias analysis for trees. |
| Copyright (C) 2004-2013 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 "tm.h" |
| #include "tree.h" |
| #include "tm_p.h" |
| #include "target.h" |
| #include "basic-block.h" |
| #include "timevar.h" /* for TV_ALIAS_STMT_WALK */ |
| #include "ggc.h" |
| #include "langhooks.h" |
| #include "flags.h" |
| #include "function.h" |
| #include "tree-pretty-print.h" |
| #include "dumpfile.h" |
| #include "gimple.h" |
| #include "tree-flow.h" |
| #include "tree-inline.h" |
| #include "params.h" |
| #include "vec.h" |
| #include "bitmap.h" |
| #include "pointer-set.h" |
| #include "alloc-pool.h" |
| #include "tree-ssa-alias.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. */ |
| |
| |
| /* 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; |
| } 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); |
| } |
| |
| |
| /* 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)) |
| || (TREE_CODE (decl) != VAR_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 base == decl; |
| else if (base |
| && CONSTANT_CLASS_P (base)) |
| return false; |
| else |
| return true; |
| } |
| |
| /* Non-aliased variables can not 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; |
| } |
| |
| /* Return true whether REF may refer to global memory. */ |
| |
| bool |
| ref_may_alias_global_p (tree ref) |
| { |
| tree base = get_base_address (ref); |
| 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; |
| } |
| |
| /* 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; |
| 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 (i = 1; i < num_ssa_names; i++) |
| { |
| tree ptr = ssa_name (i); |
| struct ptr_info_def *pi; |
| |
| if (ptr == NULL_TREE |
| || 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_global) |
| fprintf (file, " (includes global vars)"); |
| } |
| } |
| |
| /* 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) |
| { |
| if (ref->base) |
| return ref->base; |
| ref->base = get_ref_base_and_extent (ref->ref, &ref->offset, &ref->size, |
| &ref->max_size); |
| return ref->base; |
| } |
| |
| /* Returns the base object alias set of the memory reference *REF. */ |
| |
| static 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; |
| ref->ref_alias_set = get_alias_set (ref->ref); |
| return ref->ref_alias_set; |
| } |
| |
| /* Init an alias-oracle reference representation from a gimple pointer |
| PTR and a gimple size SIZE in bytes. If SIZE is NULL_TREE the 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) |
| { |
| HOST_WIDE_INT t1, t2; |
| ref->ref = NULL_TREE; |
| if (TREE_CODE (ptr) == ADDR_EXPR) |
| ref->base = get_ref_base_and_extent (TREE_OPERAND (ptr, 0), |
| &ref->offset, &t1, &t2); |
| else |
| { |
| ref->base = build2 (MEM_REF, char_type_node, |
| ptr, null_pointer_node); |
| ref->offset = 0; |
| } |
| if (size |
| && host_integerp (size, 0) |
| && TREE_INT_CST_LOW (size) * 8 / 8 == TREE_INT_CST_LOW (size)) |
| ref->max_size = ref->size = TREE_INT_CST_LOW (size) * 8; |
| else |
| ref->max_size = ref->size = -1; |
| ref->ref_alias_set = 0; |
| ref->base_alias_set = 0; |
| ref->volatile_p = false; |
| } |
| |
| /* 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); |
| |
| /* 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. */ |
| if (get_alias_set (type1) == get_alias_set (type2)) |
| return -1; |
| |
| /* The types are known to be not equal. */ |
| return 0; |
| } |
| |
| /* 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. REF2 is the only one that can |
| be a decl in which case REF2_IS_DECL is true. |
| 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, |
| HOST_WIDE_INT offset1, HOST_WIDE_INT max_size1, |
| tree ref2, |
| alias_set_type ref2_alias_set, |
| alias_set_type base2_alias_set, |
| HOST_WIDE_INT offset2, HOST_WIDE_INT max_size2, |
| bool ref2_is_decl) |
| { |
| /* 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; |
| tree *refp; |
| int same_p; |
| |
| /* Choose bases and base types to search for. */ |
| base1 = ref1; |
| while (handled_component_p (base1)) |
| base1 = TREE_OPERAND (base1, 0); |
| type1 = TREE_TYPE (base1); |
| base2 = ref2; |
| while (handled_component_p (base2)) |
| 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. */ |
| refp = &ref2; |
| while (handled_component_p (*refp) |
| && same_type_for_tbaa (TREE_TYPE (*refp), type1) == 0) |
| refp = &TREE_OPERAND (*refp, 0); |
| same_p = same_type_for_tbaa (TREE_TYPE (*refp), type1); |
| /* If we couldn't compare types we have to bail out. */ |
| if (same_p == -1) |
| return true; |
| else if (same_p == 1) |
| { |
| HOST_WIDE_INT offadj, sztmp, msztmp; |
| get_ref_base_and_extent (*refp, &offadj, &sztmp, &msztmp); |
| offset2 -= offadj; |
| get_ref_base_and_extent (base1, &offadj, &sztmp, &msztmp); |
| offset1 -= offadj; |
| return ranges_overlap_p (offset1, max_size1, offset2, max_size2); |
| } |
| /* If we didn't find a common base, try the other way around. */ |
| refp = &ref1; |
| while (handled_component_p (*refp) |
| && same_type_for_tbaa (TREE_TYPE (*refp), type2) == 0) |
| refp = &TREE_OPERAND (*refp, 0); |
| same_p = same_type_for_tbaa (TREE_TYPE (*refp), type2); |
| /* If we couldn't compare types we have to bail out. */ |
| if (same_p == -1) |
| return true; |
| else if (same_p == 1) |
| { |
| HOST_WIDE_INT offadj, sztmp, msztmp; |
| get_ref_base_and_extent (*refp, &offadj, &sztmp, &msztmp); |
| offset1 -= offadj; |
| get_ref_base_and_extent (base2, &offadj, &sztmp, &msztmp); |
| offset2 -= offadj; |
| return ranges_overlap_p (offset1, max_size1, offset2, max_size2); |
| } |
| |
| /* If we have two type access paths B1.path1 and B2.path2 they may |
| only alias if either B1 is in B2.path2 or B2 is in B1.path1. |
| But we can still have a path that goes B1.path1...B2.path2 with |
| a part that we do not see. So we can only disambiguate now |
| if there is no B2 in the tail of path1 and no B1 on the |
| tail of path2. */ |
| if (base1_alias_set == ref2_alias_set |
| || alias_set_subset_of (base1_alias_set, ref2_alias_set)) |
| return true; |
| /* If this is ptr vs. decl then we know there is no ptr ... decl path. */ |
| if (!ref2_is_decl) |
| return (base2_alias_set == ref1_alias_set |
| || alias_set_subset_of (base2_alias_set, ref1_alias_set)); |
| 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. */ |
| |
| static bool |
| decl_refs_may_alias_p (tree base1, |
| HOST_WIDE_INT offset1, HOST_WIDE_INT max_size1, |
| tree base2, |
| HOST_WIDE_INT offset2, HOST_WIDE_INT max_size2) |
| { |
| gcc_checking_assert (DECL_P (base1) && DECL_P (base2)); |
| |
| /* If both references are based on different variables, they cannot alias. */ |
| if (base1 != base2) |
| return false; |
| |
| /* If both references are based on the same variable, they cannot alias if |
| the accesses do not overlap. */ |
| return ranges_overlap_p (offset1, max_size1, offset2, max_size2); |
| } |
| |
| /* 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, |
| HOST_WIDE_INT offset1, |
| HOST_WIDE_INT max_size1 ATTRIBUTE_UNUSED, |
| alias_set_type ref1_alias_set, |
| alias_set_type base1_alias_set, |
| tree ref2 ATTRIBUTE_UNUSED, tree base2, |
| HOST_WIDE_INT offset2, HOST_WIDE_INT max_size2, |
| alias_set_type ref2_alias_set, |
| alias_set_type base2_alias_set, bool tbaa_p) |
| { |
| tree ptr1; |
| tree ptrtype1, dbase2; |
| HOST_WIDE_INT offset1p = offset1, offset2p = offset2; |
| HOST_WIDE_INT doffset1, doffset2; |
| double_int moff; |
| |
| gcc_checking_assert ((TREE_CODE (base1) == MEM_REF |
| || TREE_CODE (base1) == TARGET_MEM_REF) |
| && DECL_P (base2)); |
| |
| ptr1 = TREE_OPERAND (base1, 0); |
| |
| /* The offset embedded in MEM_REFs can be negative. Bias them |
| so that the resulting offset adjustment is positive. */ |
| moff = mem_ref_offset (base1); |
| moff = moff.alshift (BITS_PER_UNIT == 8 |
| ? 3 : exact_log2 (BITS_PER_UNIT), |
| HOST_BITS_PER_DOUBLE_INT); |
| if (moff.is_negative ()) |
| offset2p += (-moff).low; |
| else |
| offset1p += moff.low; |
| |
| /* 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_overlap_p (MAX (0, offset1p), -1, offset2p, 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; |
| |
| ptrtype1 = TREE_TYPE (TREE_OPERAND (base1, 1)); |
| |
| /* If the alias set for a pointer access is zero all bets are off. */ |
| if (base1_alias_set == -1) |
| base1_alias_set = get_deref_alias_set (ptrtype1); |
| if (base1_alias_set == 0) |
| return true; |
| if (base2_alias_set == -1) |
| base2_alias_set = get_alias_set (base2); |
| |
| /* 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; |
| /* 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 (DECL_SIZE (base2) && COMPLETE_TYPE_P (TREE_TYPE (ptrtype1)) |
| && TREE_CODE (DECL_SIZE (base2)) == INTEGER_CST |
| && TREE_CODE (TYPE_SIZE (TREE_TYPE (ptrtype1))) == INTEGER_CST |
| /* ??? 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 |
| && tree_int_cst_lt (DECL_SIZE (base2), TYPE_SIZE (TREE_TYPE (ptrtype1)))) |
| 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); |
| doffset1 = offset1; |
| doffset2 = offset2; |
| if (TREE_CODE (dbase2) == MEM_REF |
| || TREE_CODE (dbase2) == TARGET_MEM_REF) |
| { |
| double_int moff = mem_ref_offset (dbase2); |
| moff = moff.alshift (BITS_PER_UNIT == 8 |
| ? 3 : exact_log2 (BITS_PER_UNIT), |
| HOST_BITS_PER_DOUBLE_INT); |
| if (moff.is_negative ()) |
| doffset1 -= (-moff).low; |
| else |
| doffset2 -= moff.low; |
| } |
| |
| /* 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 (dbase2), TREE_TYPE (base2)) != 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. */ |
| if ((TREE_CODE (base1) != TARGET_MEM_REF |
| || (!TMR_INDEX (base1) && !TMR_INDEX2 (base1))) |
| && same_type_for_tbaa (TREE_TYPE (base1), TREE_TYPE (dbase2)) == 1) |
| return ranges_overlap_p (doffset1, max_size1, doffset2, max_size2); |
| |
| /* 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, true); |
| |
| 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, |
| HOST_WIDE_INT offset1, HOST_WIDE_INT max_size1, |
| alias_set_type ref1_alias_set, |
| alias_set_type base1_alias_set, |
| tree ref2 ATTRIBUTE_UNUSED, tree base2, |
| HOST_WIDE_INT offset2, HOST_WIDE_INT max_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)))))) |
| { |
| double_int moff; |
| /* The offset embedded in MEM_REFs can be negative. Bias them |
| so that the resulting offset adjustment is positive. */ |
| moff = mem_ref_offset (base1); |
| moff = moff.alshift (BITS_PER_UNIT == 8 |
| ? 3 : exact_log2 (BITS_PER_UNIT), |
| HOST_BITS_PER_DOUBLE_INT); |
| if (moff.is_negative ()) |
| offset2 += (-moff).low; |
| else |
| offset1 += moff.low; |
| moff = mem_ref_offset (base2); |
| moff = moff.alshift (BITS_PER_UNIT == 8 |
| ? 3 : exact_log2 (BITS_PER_UNIT), |
| HOST_BITS_PER_DOUBLE_INT); |
| if (moff.is_negative ()) |
| offset1 += (-moff).low; |
| else |
| offset2 += moff.low; |
| return ranges_overlap_p (offset1, max_size1, offset2, max_size2); |
| } |
| 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 == -1) |
| base1_alias_set = get_deref_alias_set (ptrtype1); |
| if (base1_alias_set == 0) |
| return true; |
| if (base2_alias_set == -1) |
| base2_alias_set = get_deref_alias_set (ptrtype2); |
| if (base2_alias_set == 0) |
| 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 (base1), TREE_TYPE (ptrtype1)) == 1 |
| && same_type_for_tbaa (TREE_TYPE (base2), TREE_TYPE (ptrtype2)) == 1 |
| && same_type_for_tbaa (TREE_TYPE (ptrtype1), |
| TREE_TYPE (ptrtype2)) == 1) |
| return ranges_overlap_p (offset1, max_size1, offset2, max_size2); |
| |
| /* Do type-based disambiguation. */ |
| if (base1_alias_set != base2_alias_set |
| && !alias_sets_conflict_p (base1_alias_set, base2_alias_set)) |
| return false; |
| |
| /* Do access-path based disambiguation. */ |
| if (ref1 && ref2 |
| && (handled_component_p (ref1) || handled_component_p (ref2)) |
| && same_type_for_tbaa (TREE_TYPE (base1), TREE_TYPE (ptrtype1)) == 1 |
| && same_type_for_tbaa (TREE_TYPE (base2), TREE_TYPE (ptrtype2)) == 1) |
| 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, false); |
| |
| return true; |
| } |
| |
| /* Return true, if the two memory references REF1 and REF2 may alias. */ |
| |
| bool |
| refs_may_alias_p_1 (ao_ref *ref1, ao_ref *ref2, bool tbaa_p) |
| { |
| tree base1, base2; |
| HOST_WIDE_INT offset1 = 0, offset2 = 0; |
| HOST_WIDE_INT 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 (base1, offset1, max_size1, |
| base2, offset2, max_size2); |
| |
| 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) |
| { |
| HOST_WIDE_INT tmp1; |
| tree tmp2; |
| ao_ref *tmp3; |
| tmp1 = offset1; offset1 = offset2; offset2 = tmp1; |
| tmp1 = max_size1; max_size1 = max_size2; max_size2 = tmp1; |
| tmp2 = base1; base1 = base2; base2 = tmp2; |
| tmp3 = ref1; ref1 = ref2; ref2 = tmp3; |
| 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; |
| |
| /* 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, |
| ao_ref_alias_set (ref2), -1, |
| ref1->ref, base1, |
| offset1, max_size1, |
| 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, |
| ao_ref_alias_set (ref1), -1, |
| ref2->ref, base2, |
| offset2, max_size2, |
| ao_ref_alias_set (ref2), -1, |
| tbaa_p); |
| |
| /* We really do not want to end up here, but returning true is safe. */ |
| #ifdef ENABLE_CHECKING |
| gcc_unreachable (); |
| #else |
| return true; |
| #endif |
| } |
| |
| bool |
| refs_may_alias_p (tree ref1, tree ref2) |
| { |
| ao_ref r1, r2; |
| bool res; |
| ao_ref_init (&r1, ref1); |
| ao_ref_init (&r2, ref2); |
| res = refs_may_alias_p_1 (&r1, &r2, true); |
| if (res) |
| ++alias_stats.refs_may_alias_p_may_alias; |
| else |
| ++alias_stats.refs_may_alias_p_no_alias; |
| return res; |
| } |
| |
| /* 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); |
| } |
| |
| /* If the call CALL may use the memory reference REF return true, |
| otherwise return false. */ |
| |
| static bool |
| ref_maybe_used_by_call_p_1 (gimple call, ao_ref *ref) |
| { |
| 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; |
| |
| base = ao_ref_base (ref); |
| if (!base) |
| return true; |
| |
| /* 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 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; |
| |
| callee = gimple_call_fndecl (call); |
| |
| /* Handle those builtin functions explicitly that do not act as |
| escape points. See tree-ssa-structalias.c:find_func_aliases |
| for the list of builtins we might need to handle here. */ |
| if (callee != NULL_TREE |
| && DECL_BUILT_IN_CLASS (callee) == BUILT_IN_NORMAL) |
| switch (DECL_FUNCTION_CODE (callee)) |
| { |
| /* All the following functions read memory pointed to by |
| their second argument. strcat/strncat additionally |
| reads memory pointed to by the first argument. */ |
| case BUILT_IN_STRCAT: |
| case BUILT_IN_STRNCAT: |
| { |
| ao_ref dref; |
| ao_ref_init_from_ptr_and_size (&dref, |
| gimple_call_arg (call, 0), |
| NULL_TREE); |
| if (refs_may_alias_p_1 (&dref, ref, false)) |
| return true; |
| } |
| /* FALLTHRU */ |
| case BUILT_IN_STRCPY: |
| case BUILT_IN_STRNCPY: |
| case BUILT_IN_MEMCPY: |
| case BUILT_IN_MEMMOVE: |
| case BUILT_IN_MEMPCPY: |
| case BUILT_IN_STPCPY: |
| case BUILT_IN_STPNCPY: |
| case BUILT_IN_TM_MEMCPY: |
| case BUILT_IN_TM_MEMMOVE: |
| { |
| ao_ref dref; |
| tree size = NULL_TREE; |
| if (gimple_call_num_args (call) == 3) |
| size = gimple_call_arg (call, 2); |
| ao_ref_init_from_ptr_and_size (&dref, |
| gimple_call_arg (call, 1), |
| size); |
| return refs_may_alias_p_1 (&dref, ref, false); |
| } |
| case BUILT_IN_STRCAT_CHK: |
| case BUILT_IN_STRNCAT_CHK: |
| { |
| ao_ref dref; |
| ao_ref_init_from_ptr_and_size (&dref, |
| gimple_call_arg (call, 0), |
| NULL_TREE); |
| if (refs_may_alias_p_1 (&dref, ref, false)) |
| return true; |
| } |
| /* FALLTHRU */ |
| case BUILT_IN_STRCPY_CHK: |
| case BUILT_IN_STRNCPY_CHK: |
| case BUILT_IN_MEMCPY_CHK: |
| case BUILT_IN_MEMMOVE_CHK: |
| case BUILT_IN_MEMPCPY_CHK: |
| case BUILT_IN_STPCPY_CHK: |
| case BUILT_IN_STPNCPY_CHK: |
| { |
| ao_ref dref; |
| tree size = NULL_TREE; |
| if (gimple_call_num_args (call) == 4) |
| size = gimple_call_arg (call, 2); |
| ao_ref_init_from_ptr_and_size (&dref, |
| gimple_call_arg (call, 1), |
| size); |
| return refs_may_alias_p_1 (&dref, ref, false); |
| } |
| case BUILT_IN_BCOPY: |
| { |
| ao_ref dref; |
| tree size = gimple_call_arg (call, 2); |
| ao_ref_init_from_ptr_and_size (&dref, |
| gimple_call_arg (call, 0), |
| size); |
| return refs_may_alias_p_1 (&dref, ref, false); |
| } |
| |
| /* The following functions read memory pointed to by their |
| first argument. */ |
| CASE_BUILT_IN_TM_LOAD (1): |
| CASE_BUILT_IN_TM_LOAD (2): |
| CASE_BUILT_IN_TM_LOAD (4): |
| CASE_BUILT_IN_TM_LOAD (8): |
| CASE_BUILT_IN_TM_LOAD (FLOAT): |
| CASE_BUILT_IN_TM_LOAD (DOUBLE): |
| CASE_BUILT_IN_TM_LOAD (LDOUBLE): |
| CASE_BUILT_IN_TM_LOAD (M64): |
| CASE_BUILT_IN_TM_LOAD (M128): |
| CASE_BUILT_IN_TM_LOAD (M256): |
| case BUILT_IN_TM_LOG: |
| case BUILT_IN_TM_LOG_1: |
| case BUILT_IN_TM_LOG_2: |
| case BUILT_IN_TM_LOG_4: |
| case BUILT_IN_TM_LOG_8: |
| case BUILT_IN_TM_LOG_FLOAT: |
| case BUILT_IN_TM_LOG_DOUBLE: |
| case BUILT_IN_TM_LOG_LDOUBLE: |
| case BUILT_IN_TM_LOG_M64: |
| case BUILT_IN_TM_LOG_M128: |
| case BUILT_IN_TM_LOG_M256: |
| return ptr_deref_may_alias_ref_p_1 (gimple_call_arg (call, 0), ref); |
| |
| /* These read memory pointed to by the first argument. */ |
| case BUILT_IN_STRDUP: |
| case BUILT_IN_STRNDUP: |
| { |
| ao_ref dref; |
| tree size = NULL_TREE; |
| if (gimple_call_num_args (call) == 2) |
| size = gimple_call_arg (call, 1); |
| ao_ref_init_from_ptr_and_size (&dref, |
| gimple_call_arg (call, 0), |
| size); |
| return refs_may_alias_p_1 (&dref, ref, false); |
| } |
| /* The following builtins do not read from memory. */ |
| case BUILT_IN_FREE: |
| case BUILT_IN_MALLOC: |
| case BUILT_IN_CALLOC: |
| case BUILT_IN_ALLOCA: |
| case BUILT_IN_ALLOCA_WITH_ALIGN: |
| case BUILT_IN_STACK_SAVE: |
| case BUILT_IN_STACK_RESTORE: |
| case BUILT_IN_MEMSET: |
| case BUILT_IN_TM_MEMSET: |
| case BUILT_IN_MEMSET_CHK: |
| case BUILT_IN_FREXP: |
| case BUILT_IN_FREXPF: |
| case BUILT_IN_FREXPL: |
| case BUILT_IN_GAMMA_R: |
| case BUILT_IN_GAMMAF_R: |
| case BUILT_IN_GAMMAL_R: |
| case BUILT_IN_LGAMMA_R: |
| case BUILT_IN_LGAMMAF_R: |
| case BUILT_IN_LGAMMAL_R: |
| case BUILT_IN_MODF: |
| case BUILT_IN_MODFF: |
| case BUILT_IN_MODFL: |
| case BUILT_IN_REMQUO: |
| case BUILT_IN_REMQUOF: |
| case BUILT_IN_REMQUOL: |
| case BUILT_IN_SINCOS: |
| case BUILT_IN_SINCOSF: |
| case BUILT_IN_SINCOSL: |
| case BUILT_IN_ASSUME_ALIGNED: |
| case BUILT_IN_VA_END: |
| return false; |
| /* __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_TASKWAIT: |
| 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_ORDERED_START: |
| case BUILT_IN_GOMP_ORDERED_END: |
| case BUILT_IN_GOMP_PARALLEL_END: |
| case BUILT_IN_GOMP_SECTIONS_END: |
| case BUILT_IN_GOMP_SINGLE_COPY_START: |
| case BUILT_IN_GOMP_SINGLE_COPY_END: |
| return true; |
| |
| default: |
| /* Fallthru to general call handling. */; |
| } |
| |
| /* Check if base is a global static variable that is not read |
| by the function. */ |
| if (callee != NULL_TREE |
| && TREE_CODE (base) == VAR_DECL |
| && TREE_STATIC (base)) |
| { |
| struct cgraph_node *node = cgraph_get_node (callee); |
| bitmap not_read; |
| |
| /* 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 |
| && (not_read = ipa_reference_get_not_read_global (node)) |
| && bitmap_bit_p (not_read, DECL_UID (base))) |
| 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, true)) |
| return true; |
| } |
| } |
| |
| return false; |
| } |
| |
| static bool |
| ref_maybe_used_by_call_p (gimple call, tree ref) |
| { |
| ao_ref r; |
| bool res; |
| ao_ref_init (&r, ref); |
| res = ref_maybe_used_by_call_p_1 (call, &r); |
| 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, tree ref) |
| { |
| 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); |
| } |
| else if (is_gimple_call (stmt)) |
| return ref_maybe_used_by_call_p (stmt, ref); |
| else if (gimple_code (stmt) == GIMPLE_RETURN) |
| { |
| tree retval = gimple_return_retval (stmt); |
| tree base; |
| if (retval |
| && TREE_CODE (retval) != SSA_NAME |
| && !is_gimple_min_invariant (retval) |
| && refs_may_alias_p (retval, ref)) |
| return true; |
| /* If ref escapes the function then the return acts as a use. */ |
| base = get_base_address (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; |
| } |
| |
| /* If the call in statement CALL may clobber the memory reference REF |
| return true, otherwise return false. */ |
| |
| static bool |
| call_may_clobber_ref_p_1 (gimple call, ao_ref *ref) |
| { |
| 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; |
| |
| 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; |
| |
| callee = gimple_call_fndecl (call); |
| |
| /* Handle those builtin functions explicitly that do not act as |
| escape points. See tree-ssa-structalias.c:find_func_aliases |
| for the list of builtins we might need to handle here. */ |
| if (callee != NULL_TREE |
| && DECL_BUILT_IN_CLASS (callee) == BUILT_IN_NORMAL) |
| switch (DECL_FUNCTION_CODE (callee)) |
| { |
| /* All the following functions clobber memory pointed to by |
| their first argument. */ |
| case BUILT_IN_STRCPY: |
| case BUILT_IN_STRNCPY: |
| case BUILT_IN_MEMCPY: |
| case BUILT_IN_MEMMOVE: |
| case BUILT_IN_MEMPCPY: |
| case BUILT_IN_STPCPY: |
| case BUILT_IN_STPNCPY: |
| case BUILT_IN_STRCAT: |
| case BUILT_IN_STRNCAT: |
| case BUILT_IN_MEMSET: |
| case BUILT_IN_TM_MEMSET: |
| CASE_BUILT_IN_TM_STORE (1): |
| CASE_BUILT_IN_TM_STORE (2): |
| CASE_BUILT_IN_TM_STORE (4): |
| CASE_BUILT_IN_TM_STORE (8): |
| CASE_BUILT_IN_TM_STORE (FLOAT): |
| CASE_BUILT_IN_TM_STORE (DOUBLE): |
| CASE_BUILT_IN_TM_STORE (LDOUBLE): |
| CASE_BUILT_IN_TM_STORE (M64): |
| CASE_BUILT_IN_TM_STORE (M128): |
| CASE_BUILT_IN_TM_STORE (M256): |
| case BUILT_IN_TM_MEMCPY: |
| case BUILT_IN_TM_MEMMOVE: |
| { |
| ao_ref dref; |
| tree size = NULL_TREE; |
| /* Don't pass in size for strncat, as the maximum size |
| is strlen (dest) + n + 1 instead of n, resp. |
| n + 1 at dest + strlen (dest), but strlen (dest) isn't |
| known. */ |
| if (gimple_call_num_args (call) == 3 |
| && DECL_FUNCTION_CODE (callee) != BUILT_IN_STRNCAT) |
| size = gimple_call_arg (call, 2); |
| ao_ref_init_from_ptr_and_size (&dref, |
| gimple_call_arg (call, 0), |
| size); |
| return refs_may_alias_p_1 (&dref, ref, false); |
| } |
| case BUILT_IN_STRCPY_CHK: |
| case BUILT_IN_STRNCPY_CHK: |
| case BUILT_IN_MEMCPY_CHK: |
| case BUILT_IN_MEMMOVE_CHK: |
| case BUILT_IN_MEMPCPY_CHK: |
| case BUILT_IN_STPCPY_CHK: |
| case BUILT_IN_STPNCPY_CHK: |
| case BUILT_IN_STRCAT_CHK: |
| case BUILT_IN_STRNCAT_CHK: |
| case BUILT_IN_MEMSET_CHK: |
| { |
| ao_ref dref; |
| tree size = NULL_TREE; |
| /* Don't pass in size for __strncat_chk, as the maximum size |
| is strlen (dest) + n + 1 instead of n, resp. |
| n + 1 at dest + strlen (dest), but strlen (dest) isn't |
| known. */ |
| if (gimple_call_num_args (call) == 4 |
| && DECL_FUNCTION_CODE (callee) != BUILT_IN_STRNCAT_CHK) |
| size = gimple_call_arg (call, 2); |
| ao_ref_init_from_ptr_and_size (&dref, |
| gimple_call_arg (call, 0), |
| size); |
| return refs_may_alias_p_1 (&dref, ref, false); |
| } |
| case BUILT_IN_BCOPY: |
| { |
| ao_ref dref; |
| tree size = gimple_call_arg (call, 2); |
| ao_ref_init_from_ptr_and_size (&dref, |
| gimple_call_arg (call, 1), |
| size); |
| return refs_may_alias_p_1 (&dref, ref, false); |
| } |
| /* Allocating memory does not have any side-effects apart from |
| being the definition point for the pointer. */ |
| case BUILT_IN_MALLOC: |
| case BUILT_IN_CALLOC: |
| case BUILT_IN_STRDUP: |
| case BUILT_IN_STRNDUP: |
| /* Unix98 specifies that errno is set on allocation failure. */ |
| if (flag_errno_math |
| && targetm.ref_may_alias_errno (ref)) |
| return true; |
| return false; |
| case BUILT_IN_STACK_SAVE: |
| case BUILT_IN_ALLOCA: |
| case BUILT_IN_ALLOCA_WITH_ALIGN: |
| case BUILT_IN_ASSUME_ALIGNED: |
| return false; |
| /* Freeing memory kills the pointed-to memory. More importantly |
| the call has to serve as a barrier for moving loads and stores |
| across it. */ |
| case BUILT_IN_FREE: |
| case BUILT_IN_VA_END: |
| { |
| tree ptr = gimple_call_arg (call, 0); |
| return ptr_deref_may_alias_ref_p_1 (ptr, ref); |
| } |
| case BUILT_IN_GAMMA_R: |
| case BUILT_IN_GAMMAF_R: |
| case BUILT_IN_GAMMAL_R: |
| case BUILT_IN_LGAMMA_R: |
| case BUILT_IN_LGAMMAF_R: |
| case BUILT_IN_LGAMMAL_R: |
| { |
| tree out = gimple_call_arg (call, 1); |
| if (ptr_deref_may_alias_ref_p_1 (out, ref)) |
| return true; |
| if (flag_errno_math) |
| break; |
| return false; |
| } |
| case BUILT_IN_FREXP: |
| case BUILT_IN_FREXPF: |
| case BUILT_IN_FREXPL: |
| case BUILT_IN_MODF: |
| case BUILT_IN_MODFF: |
| case BUILT_IN_MODFL: |
| { |
| tree out = gimple_call_arg (call, 1); |
| return ptr_deref_may_alias_ref_p_1 (out, ref); |
| } |
| case BUILT_IN_REMQUO: |
| case BUILT_IN_REMQUOF: |
| case BUILT_IN_REMQUOL: |
| { |
| tree out = gimple_call_arg (call, 2); |
| if (ptr_deref_may_alias_ref_p_1 (out, ref)) |
| return true; |
| if (flag_errno_math) |
| break; |
| return false; |
| } |
| case BUILT_IN_SINCOS: |
| case BUILT_IN_SINCOSF: |
| case BUILT_IN_SINCOSL: |
| { |
| tree sin = gimple_call_arg (call, 1); |
| tree cos = gimple_call_arg (call, 2); |
| return (ptr_deref_may_alias_ref_p_1 (sin, ref) |
| || ptr_deref_may_alias_ref_p_1 (cos, ref)); |
| } |
| /* __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_TASKWAIT: |
| 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_ORDERED_START: |
| case BUILT_IN_GOMP_ORDERED_END: |
| case BUILT_IN_GOMP_PARALLEL_END: |
| case BUILT_IN_GOMP_SECTIONS_END: |
| case BUILT_IN_GOMP_SINGLE_COPY_START: |
| case BUILT_IN_GOMP_SINGLE_COPY_END: |
| return true; |
| default: |
| /* Fallthru to general call handling. */; |
| } |
| |
| /* Check if base is a global static variable that is not written |
| by the function. */ |
| if (callee != NULL_TREE |
| && TREE_CODE (base) == VAR_DECL |
| && TREE_STATIC (base)) |
| { |
| struct cgraph_node *node = cgraph_get_node (callee); |
| bitmap not_written; |
| |
| if (node |
| && (not_written = ipa_reference_get_not_written_global (node)) |
| && bitmap_bit_p (not_written, DECL_UID (base))) |
| 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 (gimple call, tree ref) |
| { |
| bool res; |
| ao_ref r; |
| ao_ref_init (&r, ref); |
| res = call_may_clobber_ref_p_1 (call, &r); |
| 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) |
| { |
| 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, true)) |
| return true; |
| } |
| |
| return call_may_clobber_ref_p_1 (stmt, ref); |
| } |
| 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, true); |
| } |
| } |
| else if (gimple_code (stmt) == GIMPLE_ASM) |
| return true; |
| |
| return false; |
| } |
| |
| bool |
| stmt_may_clobber_ref_p (gimple stmt, tree ref) |
| { |
| ao_ref r; |
| ao_ref_init (&r, ref); |
| return stmt_may_clobber_ref_p_1 (stmt, &r); |
| } |
| |
| /* If STMT kills the memory reference REF return true, otherwise |
| return false. */ |
| |
| static bool |
| stmt_kills_ref_p_1 (gimple stmt, ao_ref *ref) |
| { |
| /* For a must-alias check we need to be able to constrain |
| the access properly. */ |
| ao_ref_base (ref); |
| if (ref->max_size == -1) |
| return false; |
| |
| if (gimple_has_lhs (stmt) |
| && TREE_CODE (gimple_get_lhs (stmt)) != SSA_NAME |
| /* The assignment is not necessarily carried out if it can throw |
| and we can catch it in the current function where we could inspect |
| the previous value. |
| ??? We only need to care about the RHS throwing. For aggregate |
| assignments or similar calls and non-call exceptions the LHS |
| might throw as well. */ |
| && !stmt_can_throw_internal (stmt)) |
| { |
| tree base, lhs = gimple_get_lhs (stmt); |
| HOST_WIDE_INT size, offset, max_size; |
| base = get_ref_base_and_extent (lhs, &offset, &size, &max_size); |
| /* We can get MEM[symbol: sZ, index: D.8862_1] here, |
| so base == ref->base does not always hold. */ |
| if (base == ref->base) |
| { |
| /* For a must-alias check we need to be able to constrain |
| the access properly. */ |
| if (size != -1 && size == max_size) |
| { |
| if (offset <= ref->offset |
| && offset + size >= ref->offset + ref->max_size) |
| return true; |
| } |
| } |
| } |
| |
| if (is_gimple_call (stmt)) |
| { |
| tree callee = gimple_call_fndecl (stmt); |
| if (callee != NULL_TREE |
| && DECL_BUILT_IN_CLASS (callee) == BUILT_IN_NORMAL) |
| switch (DECL_FUNCTION_CODE (callee)) |
| { |
| case BUILT_IN_MEMCPY: |
| case BUILT_IN_MEMPCPY: |
| case BUILT_IN_MEMMOVE: |
| case BUILT_IN_MEMSET: |
| case BUILT_IN_MEMCPY_CHK: |
| case BUILT_IN_MEMPCPY_CHK: |
| case BUILT_IN_MEMMOVE_CHK: |
| case BUILT_IN_MEMSET_CHK: |
| { |
| tree dest = gimple_call_arg (stmt, 0); |
| tree len = gimple_call_arg (stmt, 2); |
| tree base = NULL_TREE; |
| HOST_WIDE_INT offset = 0; |
| if (!host_integerp (len, 0)) |
| return false; |
| if (TREE_CODE (dest) == ADDR_EXPR) |
| base = get_addr_base_and_unit_offset (TREE_OPERAND (dest, 0), |
| &offset); |
| else if (TREE_CODE (dest) == SSA_NAME) |
| base = dest; |
| if (base |
| && base == ao_ref_base (ref)) |
| { |
| HOST_WIDE_INT size = TREE_INT_CST_LOW (len); |
| if (offset <= ref->offset / BITS_PER_UNIT |
| && (offset + size |
| >= ((ref->offset + ref->max_size + BITS_PER_UNIT - 1) |
| / BITS_PER_UNIT))) |
| return true; |
| } |
| break; |
| } |
| |
| case BUILT_IN_VA_END: |
| { |
| tree ptr = gimple_call_arg (stmt, 0); |
| if (TREE_CODE (ptr) == ADDR_EXPR) |
| { |
| tree base = ao_ref_base (ref); |
| if (TREE_OPERAND (ptr, 0) == base) |
| return true; |
| } |
| break; |
| } |
| |
| default:; |
| } |
| } |
| return false; |
| } |
| |
| bool |
| stmt_kills_ref_p (gimple stmt, tree ref) |
| { |
| ao_ref r; |
| ao_ref_init (&r, ref); |
| return stmt_kills_ref_p_1 (stmt, &r); |
| } |
| |
| |
| /* Walk the virtual use-def chain of VUSE until hitting the virtual operand |
| TARGET or a statement clobbering the memory reference REF in which |
| case false is returned. The walk starts with VUSE, one argument of PHI. */ |
| |
| static bool |
| maybe_skip_until (gimple phi, tree target, ao_ref *ref, |
| tree vuse, unsigned int *cnt, bitmap *visited, |
| bool abort_on_visited) |
| { |
| basic_block bb = gimple_bb (phi); |
| |
| if (!*visited) |
| *visited = BITMAP_ALLOC (NULL); |
| |
| bitmap_set_bit (*visited, SSA_NAME_VERSION (PHI_RESULT (phi))); |
| |
| /* Walk until we hit the target. */ |
| while (vuse != target) |
| { |
| gimple def_stmt = SSA_NAME_DEF_STMT (vuse); |
| /* Recurse for PHI nodes. */ |
| if (gimple_code (def_stmt) == GIMPLE_PHI) |
| { |
| /* An already visited PHI node ends the walk successfully. */ |
| if (bitmap_bit_p (*visited, SSA_NAME_VERSION (PHI_RESULT (def_stmt)))) |
| return !abort_on_visited; |
| vuse = get_continuation_for_phi (def_stmt, ref, cnt, |
| visited, abort_on_visited); |
| if (!vuse) |
| return false; |
| continue; |
| } |
| else if (gimple_nop_p (def_stmt)) |
| return false; |
| else |
| { |
| /* A clobbering statement or the end of the IL ends it failing. */ |
| ++*cnt; |
| if (stmt_may_clobber_ref_p_1 (def_stmt, ref)) |
| return false; |
| } |
| /* If we reach a new basic-block see if we already skipped it |
| in a previous walk that ended successfully. */ |
| if (gimple_bb (def_stmt) != bb) |
| { |
| if (!bitmap_set_bit (*visited, SSA_NAME_VERSION (vuse))) |
| return !abort_on_visited; |
| bb = gimple_bb (def_stmt); |
| } |
| vuse = gimple_vuse (def_stmt); |
| } |
| return true; |
| } |
| |
| /* For two PHI arguments ARG0 and ARG1 try to skip non-aliasing code |
| until we hit the phi argument definition that dominates the other one. |
| Return that, or NULL_TREE if there is no such definition. */ |
| |
| static tree |
| get_continuation_for_phi_1 (gimple phi, tree arg0, tree arg1, |
| ao_ref *ref, unsigned int *cnt, |
| bitmap *visited, bool abort_on_visited) |
| { |
| gimple def0 = SSA_NAME_DEF_STMT (arg0); |
| gimple def1 = SSA_NAME_DEF_STMT (arg1); |
| tree common_vuse; |
| |
| if (arg0 == arg1) |
| return arg0; |
| else if (gimple_nop_p (def0) |
| || (!gimple_nop_p (def1) |
| && dominated_by_p (CDI_DOMINATORS, |
| gimple_bb (def1), gimple_bb (def0)))) |
| { |
| if (maybe_skip_until (phi, arg0, ref, arg1, cnt, |
| visited, abort_on_visited)) |
| return arg0; |
| } |
| else if (gimple_nop_p (def1) |
| || dominated_by_p (CDI_DOMINATORS, |
| gimple_bb (def0), gimple_bb (def1))) |
| { |
| if (maybe_skip_until (phi, arg1, ref, arg0, cnt, |
| visited, abort_on_visited)) |
| return arg1; |
| } |
| /* Special case of a diamond: |
| MEM_1 = ... |
| goto (cond) ? L1 : L2 |
| L1: store1 = ... #MEM_2 = vuse(MEM_1) |
| goto L3 |
| L2: store2 = ... #MEM_3 = vuse(MEM_1) |
| L3: MEM_4 = PHI<MEM_2, MEM_3> |
| We were called with the PHI at L3, MEM_2 and MEM_3 don't |
| dominate each other, but still we can easily skip this PHI node |
| if we recognize that the vuse MEM operand is the same for both, |
| and that we can skip both statements (they don't clobber us). |
| This is still linear. Don't use maybe_skip_until, that might |
| potentially be slow. */ |
| else if ((common_vuse = gimple_vuse (def0)) |
| && common_vuse == gimple_vuse (def1)) |
| { |
| *cnt += 2; |
| if (!stmt_may_clobber_ref_p_1 (def0, ref) |
| && !stmt_may_clobber_ref_p_1 (def1, ref)) |
| return common_vuse; |
| } |
| |
| return NULL_TREE; |
| } |
| |
| |
| /* Starting from a PHI node for the virtual operand of the memory reference |
| REF find a continuation virtual operand that allows to continue walking |
| statements dominating PHI skipping only statements that cannot possibly |
| clobber REF. Increments *CNT for each alias disambiguation done. |
| Returns NULL_TREE if no suitable virtual operand can be found. */ |
| |
| tree |
| get_continuation_for_phi (gimple phi, ao_ref *ref, |
| unsigned int *cnt, bitmap *visited, |
| bool abort_on_visited) |
| { |
| unsigned nargs = gimple_phi_num_args (phi); |
| |
| /* Through a single-argument PHI we can simply look through. */ |
| if (nargs == 1) |
| return PHI_ARG_DEF (phi, 0); |
| |
| /* For two or more arguments try to pairwise skip non-aliasing code |
| until we hit the phi argument definition that dominates the other one. */ |
| else if (nargs >= 2) |
| { |
| tree arg0, arg1; |
| unsigned i; |
| |
| /* Find a candidate for the virtual operand which definition |
| dominates those of all others. */ |
| arg0 = PHI_ARG_DEF (phi, 0); |
| if (!SSA_NAME_IS_DEFAULT_DEF (arg0)) |
| for (i = 1; i < nargs; ++i) |
| { |
| arg1 = PHI_ARG_DEF (phi, i); |
| if (SSA_NAME_IS_DEFAULT_DEF (arg1)) |
| { |
| arg0 = arg1; |
| break; |
| } |
| if (dominated_by_p (CDI_DOMINATORS, |
| gimple_bb (SSA_NAME_DEF_STMT (arg0)), |
| gimple_bb (SSA_NAME_DEF_STMT (arg1)))) |
| arg0 = arg1; |
| } |
| |
| /* Then pairwise reduce against the found candidate. */ |
| for (i = 0; i < nargs; ++i) |
| { |
| arg1 = PHI_ARG_DEF (phi, i); |
| arg0 = get_continuation_for_phi_1 (phi, arg0, arg1, ref, |
| cnt, visited, abort_on_visited); |
| if (!arg0) |
| return NULL_TREE; |
| } |
| |
| return arg0; |
| } |
| |
| return NULL_TREE; |
| } |
| |
| /* Based on the memory reference REF and its virtual use VUSE call |
| WALKER for each virtual use that is equivalent to VUSE, including VUSE |
| itself. That is, for each virtual use for which its defining statement |
| does not clobber REF. |
| |
| WALKER is called with REF, the current virtual use and DATA. If |
| WALKER returns non-NULL the walk stops and its result is returned. |
| At the end of a non-successful walk NULL is returned. |
| |
| TRANSLATE if non-NULL is called with a pointer to REF, the virtual |
| use which definition is a statement that may clobber REF and DATA. |
| If TRANSLATE returns (void *)-1 the walk stops and NULL is returned. |
| If TRANSLATE returns non-NULL the walk stops and its result is returned. |
| If TRANSLATE returns NULL the walk continues and TRANSLATE is supposed |
| to adjust REF and *DATA to make that valid. |
| |
| TODO: Cache the vector of equivalent vuses per ref, vuse pair. */ |
| |
| void * |
| walk_non_aliased_vuses (ao_ref *ref, tree vuse, |
| void *(*walker)(ao_ref *, tree, unsigned int, void *), |
| void *(*translate)(ao_ref *, tree, void *), void *data) |
| { |
| bitmap visited = NULL; |
| void *res; |
| unsigned int cnt = 0; |
| bool translated = false; |
| |
| timevar_push (TV_ALIAS_STMT_WALK); |
| |
| do |
| { |
| gimple def_stmt; |
| |
| /* ??? Do we want to account this to TV_ALIAS_STMT_WALK? */ |
| res = (*walker) (ref, vuse, cnt, data); |
| /* Abort walk. */ |
| if (res == (void *)-1) |
| { |
| res = NULL; |
| break; |
| } |
| /* Lookup succeeded. */ |
| else if (res != NULL) |
| break; |
| |
| def_stmt = SSA_NAME_DEF_STMT (vuse); |
| if (gimple_nop_p (def_stmt)) |
| break; |
| else if (gimple_code (def_stmt) == GIMPLE_PHI) |
| vuse = get_continuation_for_phi (def_stmt, ref, &cnt, |
| &visited, translated); |
| else |
| { |
| cnt++; |
| if (stmt_may_clobber_ref_p_1 (def_stmt, ref)) |
| { |
| if (!translate) |
| break; |
| res = (*translate) (ref, vuse, data); |
| /* Failed lookup and translation. */ |
| if (res == (void *)-1) |
| { |
| res = NULL; |
| break; |
| } |
| /* Lookup succeeded. */ |
| else if (res != NULL) |
| break; |
| /* Translation succeeded, continue walking. */ |
| translated = true; |
| } |
| vuse = gimple_vuse (def_stmt); |
| } |
| } |
| while (vuse); |
| |
| if (visited) |
| BITMAP_FREE (visited); |
| |
| timevar_pop (TV_ALIAS_STMT_WALK); |
| |
| return res; |
| } |
| |
| |
| /* Based on the memory reference REF call WALKER for each vdef which |
| defining statement may clobber REF, starting with VDEF. If REF |
| is NULL_TREE, each defining statement is visited. |
| |
| WALKER is called with REF, the current vdef and DATA. If WALKER |
| returns true the walk is stopped, otherwise it continues. |
| |
| At PHI nodes walk_aliased_vdefs forks into one walk for reach |
| PHI argument (but only one walk continues on merge points), the |
| return value is true if any of the walks was successful. |
| |
| The function returns the number of statements walked. */ |
| |
| static unsigned int |
| walk_aliased_vdefs_1 (ao_ref *ref, tree vdef, |
| bool (*walker)(ao_ref *, tree, void *), void *data, |
| bitmap *visited, unsigned int cnt) |
| { |
| do |
| { |
| gimple def_stmt = SSA_NAME_DEF_STMT (vdef); |
| |
| if (*visited |
| && !bitmap_set_bit (*visited, SSA_NAME_VERSION (vdef))) |
| return cnt; |
| |
| if (gimple_nop_p (def_stmt)) |
| return cnt; |
| else if (gimple_code (def_stmt) == GIMPLE_PHI) |
| { |
| unsigned i; |
| if (!*visited) |
| *visited = BITMAP_ALLOC (NULL); |
| for (i = 0; i < gimple_phi_num_args (def_stmt); ++i) |
| cnt += walk_aliased_vdefs_1 (ref, gimple_phi_arg_def (def_stmt, i), |
| walker, data, visited, 0); |
| return cnt; |
| } |
| |
| /* ??? Do we want to account this to TV_ALIAS_STMT_WALK? */ |
| cnt++; |
| if ((!ref |
| || stmt_may_clobber_ref_p_1 (def_stmt, ref)) |
| && (*walker) (ref, vdef, data)) |
| return cnt; |
| |
| vdef = gimple_vuse (def_stmt); |
| } |
| while (1); |
| } |
| |
| unsigned int |
| walk_aliased_vdefs (ao_ref *ref, tree vdef, |
| bool (*walker)(ao_ref *, tree, void *), void *data, |
| bitmap *visited) |
| { |
| bitmap local_visited = NULL; |
| unsigned int ret; |
| |
| timevar_push (TV_ALIAS_STMT_WALK); |
| |
| ret = walk_aliased_vdefs_1 (ref, vdef, walker, data, |
| visited ? visited : &local_visited, 0); |
| if (local_visited) |
| BITMAP_FREE (local_visited); |
| |
| timevar_pop (TV_ALIAS_STMT_WALK); |
| |
| return ret; |
| } |
| |