| /* Alias analysis for trees. |
| Copyright (C) 2004, 2005, 2006, 2007, 2008, 2009, 2010 |
| 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 "rtl.h" |
| #include "tm_p.h" |
| #include "hard-reg-set.h" |
| #include "basic-block.h" |
| #include "timevar.h" |
| #include "expr.h" |
| #include "ggc.h" |
| #include "langhooks.h" |
| #include "flags.h" |
| #include "function.h" |
| #include "diagnostic.h" |
| #include "tree-dump.h" |
| #include "gimple.h" |
| #include "tree-flow.h" |
| #include "tree-inline.h" |
| #include "tree-pass.h" |
| #include "convert.h" |
| #include "params.h" |
| #include "ipa-type-escape.h" |
| #include "vec.h" |
| #include "bitmap.h" |
| #include "vecprim.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; |
| |
| gcc_assert ((TREE_CODE (ptr) == SSA_NAME |
| || TREE_CODE (ptr) == ADDR_EXPR |
| || TREE_CODE (ptr) == INTEGER_CST) |
| && (TREE_CODE (decl) == VAR_DECL |
| || TREE_CODE (decl) == PARM_DECL |
| || TREE_CODE (decl) == RESULT_DECL)); |
| |
| /* Non-aliased variables can not be pointed to. */ |
| if (!may_be_aliased (decl)) |
| return false; |
| |
| /* 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 |
| && INDIRECT_REF_P (base)) |
| ptr = TREE_OPERAND (base, 0); |
| else if (base |
| && SSA_VAR_P (base)) |
| return operand_equal_p (base, decl, 0); |
| else if (base |
| && CONSTANT_CLASS_P (base)) |
| return false; |
| else |
| return true; |
| } |
| |
| /* We can end up with dereferencing constant pointers. |
| Just bail out in this case. */ |
| if (TREE_CODE (ptr) == INTEGER_CST) |
| return true; |
| |
| /* 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; |
| |
| /* If the decl can be used as a restrict tag and we have a restrict |
| pointer and that pointers points-to set doesn't contain this decl |
| then they can't alias. */ |
| if (DECL_RESTRICTED_P (decl) |
| && TYPE_RESTRICT (TREE_TYPE (ptr)) |
| && pi->pt.vars_contains_restrict) |
| return bitmap_bit_p (pi->pt.vars, DECL_UID (decl)); |
| |
| 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. */ |
| |
| static bool |
| ptr_derefs_may_alias_p (tree ptr1, tree ptr2) |
| { |
| struct ptr_info_def *pi1, *pi2; |
| |
| gcc_assert ((TREE_CODE (ptr1) == SSA_NAME |
| || TREE_CODE (ptr1) == ADDR_EXPR |
| || TREE_CODE (ptr1) == INTEGER_CST) |
| && (TREE_CODE (ptr2) == SSA_NAME |
| || TREE_CODE (ptr2) == ADDR_EXPR |
| || TREE_CODE (ptr2) == INTEGER_CST)); |
| |
| /* 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 |
| && INDIRECT_REF_P (base)) |
| ptr1 = TREE_OPERAND (base, 0); |
| else if (base |
| && SSA_VAR_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 |
| && INDIRECT_REF_P (base)) |
| ptr2 = TREE_OPERAND (base, 0); |
| else if (base |
| && SSA_VAR_P (base)) |
| return ptr_deref_may_alias_decl_p (ptr1, base); |
| else |
| return true; |
| } |
| |
| /* We can end up with dereferencing constant pointers. |
| Just bail out in this case. */ |
| if (TREE_CODE (ptr1) == INTEGER_CST |
| || TREE_CODE (ptr2) == INTEGER_CST) |
| 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; |
| |
| /* If both pointers are restrict-qualified try to disambiguate |
| with restrict information. */ |
| if (TYPE_RESTRICT (TREE_TYPE (ptr1)) |
| && TYPE_RESTRICT (TREE_TYPE (ptr2)) |
| && !pt_solutions_same_restrict_base (&pi1->pt, &pi2->pt)) |
| return false; |
| |
| /* ??? 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 (INDIRECT_REF_P (base)) |
| return ptr_derefs_may_alias_p (ptr, TREE_OPERAND (base, 0)); |
| else if (SSA_VAR_P (base)) |
| return ptr_deref_may_alias_decl_p (ptr, base); |
| |
| return true; |
| } |
| |
| |
| /* Dump alias information on FILE. */ |
| |
| void |
| dump_alias_info (FILE *file) |
| { |
| size_t i; |
| const char *funcname |
| = lang_hooks.decl_printable_name (current_function_decl, 2); |
| referenced_var_iterator rvi; |
| tree var; |
| |
| fprintf (file, "\n\nAlias information for %s\n\n", funcname); |
| |
| fprintf (file, "Aliased symbols\n\n"); |
| |
| FOR_EACH_REFERENCED_VAR (var, rvi) |
| { |
| 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, "\nCALLUSED"); |
| dump_points_to_solution (file, &cfun->gimple_df->callused); |
| |
| 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. */ |
| |
| void |
| debug_alias_info (void) |
| { |
| dump_alias_info (stderr); |
| } |
| |
| |
| /* Return the alias information associated with pointer T. It creates a |
| new instance if none existed. */ |
| |
| struct ptr_info_def * |
| get_ptr_info (tree t) |
| { |
| struct ptr_info_def *pi; |
| |
| gcc_assert (POINTER_TYPE_P (TREE_TYPE (t))); |
| |
| pi = SSA_NAME_PTR_INFO (t); |
| if (pi == NULL) |
| { |
| pi = GGC_CNEW (struct ptr_info_def); |
| pt_solution_reset (&pi->pt); |
| SSA_NAME_PTR_INFO (t) = pi; |
| } |
| |
| return pi; |
| } |
| |
| /* 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->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. */ |
| |
| 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; |
| } |
| |
| /* 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 ATTRIBUTE_UNUSED |
| ao_ref_base_alias_set (ao_ref *ref) |
| { |
| if (ref->base_alias_set != -1) |
| return ref->base_alias_set; |
| ref->base_alias_set = get_alias_set (ao_ref_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 = build1 (INDIRECT_REF, char_type_node, ptr); |
| 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; |
| } |
| |
| /* 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, tree type1, |
| alias_set_type ref1_alias_set, |
| alias_set_type base1_alias_set, |
| HOST_WIDE_INT offset1, HOST_WIDE_INT max_size1, |
| tree ref2, tree type2, |
| 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 *refp; |
| int same_p; |
| |
| /* 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; |
| 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; |
| 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_assert (SSA_VAR_P (base1) && SSA_VAR_P (base2)); |
| |
| /* If both references are based on different variables, they cannot alias. */ |
| if (!operand_equal_p (base1, base2, 0)) |
| 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, tree ptr1, |
| HOST_WIDE_INT offset1, HOST_WIDE_INT max_size1, |
| alias_set_type ref1_alias_set, |
| alias_set_type base1_alias_set, |
| tree ref2, tree base2, |
| HOST_WIDE_INT offset2, HOST_WIDE_INT max_size2, |
| alias_set_type ref2_alias_set, |
| alias_set_type base2_alias_set) |
| { |
| /* 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). |
| They also cannot alias if the pointer may not point to the decl. */ |
| if (max_size2 != -1 |
| && !ranges_overlap_p (offset1, max_size1, 0, offset2 + max_size2)) |
| return false; |
| if (!ptr_deref_may_alias_decl_p (ptr1, base2)) |
| return false; |
| |
| /* Disambiguations that rely on strict aliasing rules follow. */ |
| if (!flag_strict_aliasing) |
| return true; |
| |
| /* 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 (ptr1); |
| if (base1_alias_set == 0) |
| return true; |
| if (base2_alias_set == -1) |
| base2_alias_set = get_alias_set (base2); |
| |
| /* 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 (same_type_for_tbaa (TREE_TYPE (TREE_TYPE (ptr1)), |
| TREE_TYPE (base2)) == 1) |
| return ranges_overlap_p (offset1, max_size1, offset2, max_size2); |
| |
| /* The only way to access a variable is through a pointer dereference |
| of the same alias set or a subset of it. */ |
| if (base1_alias_set != base2_alias_set |
| && !alias_set_subset_of (base1_alias_set, base2_alias_set)) |
| return false; |
| |
| /* Do access-path based disambiguation. */ |
| if (ref1 && ref2 |
| && handled_component_p (ref1) |
| && handled_component_p (ref2)) |
| return aliasing_component_refs_p (ref1, TREE_TYPE (TREE_TYPE (ptr1)), |
| ref1_alias_set, base1_alias_set, |
| offset1, max_size1, |
| ref2, TREE_TYPE (base2), |
| 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, tree ptr1, |
| HOST_WIDE_INT offset1, HOST_WIDE_INT max_size1, |
| alias_set_type ref1_alias_set, |
| alias_set_type base1_alias_set, |
| tree ref2, tree ptr2, |
| HOST_WIDE_INT offset2, HOST_WIDE_INT max_size2, |
| alias_set_type ref2_alias_set, |
| alias_set_type base2_alias_set) |
| { |
| /* 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 (operand_equal_p (ptr1, ptr2, 0)) |
| 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) |
| return true; |
| |
| /* 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 (ptr1); |
| if (base1_alias_set == 0) |
| return true; |
| if (base2_alias_set == -1) |
| base2_alias_set = get_deref_alias_set (ptr2); |
| 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 (same_type_for_tbaa (TREE_TYPE (TREE_TYPE (ptr1)), |
| TREE_TYPE (TREE_TYPE (ptr2))) == 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)) |
| return aliasing_component_refs_p (ref1, TREE_TYPE (TREE_TYPE (ptr1)), |
| ref1_alias_set, base1_alias_set, |
| offset1, max_size1, |
| ref2, TREE_TYPE (TREE_TYPE (ptr2)), |
| 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; |
| alias_set_type set; |
| |
| #ifdef ENABLE_CHECKING |
| gcc_assert ((!ref1->ref |
| || TREE_CODE (ref1->ref) == SSA_NAME |
| || DECL_P (ref1->ref) |
| || handled_component_p (ref1->ref) |
| || INDIRECT_REF_P (ref1->ref) |
| || TREE_CODE (ref1->ref) == TARGET_MEM_REF) |
| && (!ref2->ref |
| || TREE_CODE (ref2->ref) == SSA_NAME |
| || DECL_P (ref2->ref) |
| || handled_component_p (ref2->ref) |
| || INDIRECT_REF_P (ref2->ref) |
| || TREE_CODE (ref2->ref) == TARGET_MEM_REF)); |
| #endif |
| |
| /* 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 (base2) == SSA_NAME |
| || TREE_CODE (base1) == CONST_DECL |
| || TREE_CODE (base2) == CONST_DECL |
| || is_gimple_min_invariant (base1) |
| || is_gimple_min_invariant (base2)) |
| return false; |
| |
| /* We can end up refering 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 (base2) == FUNCTION_DECL |
| || TREE_CODE (base1) == LABEL_DECL |
| || TREE_CODE (base2) == LABEL_DECL) |
| 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 = SSA_VAR_P (base1); |
| var2_p = SSA_VAR_P (base2); |
| if (var1_p && var2_p) |
| return decl_refs_may_alias_p (base1, offset1, max_size1, |
| base2, offset2, max_size2); |
| |
| ind1_p = INDIRECT_REF_P (base1); |
| ind2_p = INDIRECT_REF_P (base2); |
| /* 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; |
| } |
| |
| /* If we are about to disambiguate pointer-vs-decl try harder to |
| see must-aliases and give leeway to some invalid cases. |
| This covers a pretty minimal set of cases only and does not |
| when called from the RTL oracle. It handles cases like |
| |
| int i = 1; |
| return *(float *)&i; |
| |
| and also fixes gfortran.dg/lto/pr40725. */ |
| if (var1_p && ind2_p |
| && cfun |
| && gimple_in_ssa_p (cfun) |
| && TREE_CODE (TREE_OPERAND (base2, 0)) == SSA_NAME) |
| { |
| gimple def_stmt = SSA_NAME_DEF_STMT (TREE_OPERAND (base2, 0)); |
| while (is_gimple_assign (def_stmt) |
| && (gimple_assign_rhs_code (def_stmt) == SSA_NAME |
| || CONVERT_EXPR_CODE_P (gimple_assign_rhs_code (def_stmt)))) |
| { |
| tree rhs = gimple_assign_rhs1 (def_stmt); |
| HOST_WIDE_INT offset, size, max_size; |
| |
| /* Look through SSA name copies and pointer conversions. */ |
| if (TREE_CODE (rhs) == SSA_NAME |
| && POINTER_TYPE_P (TREE_TYPE (rhs))) |
| { |
| def_stmt = SSA_NAME_DEF_STMT (rhs); |
| continue; |
| } |
| if (TREE_CODE (rhs) != ADDR_EXPR) |
| break; |
| |
| /* If the pointer is defined as an address based on a decl |
| use plain offset disambiguation and ignore TBAA. */ |
| rhs = TREE_OPERAND (rhs, 0); |
| rhs = get_ref_base_and_extent (rhs, &offset, &size, &max_size); |
| if (SSA_VAR_P (rhs)) |
| { |
| base2 = rhs; |
| offset2 += offset; |
| if (size != max_size |
| || max_size == -1) |
| max_size2 = -1; |
| return decl_refs_may_alias_p (base1, offset1, max_size1, |
| base2, offset2, max_size2); |
| } |
| |
| /* Do not continue looking through &p->x to limit time |
| complexity. */ |
| break; |
| } |
| } |
| |
| /* 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 one reference is a TARGET_MEM_REF weird things are allowed. Still |
| TBAA disambiguation based on the access type is possible, so bail |
| out only after that check. */ |
| if ((ref1->ref && TREE_CODE (ref1->ref) == TARGET_MEM_REF) |
| || (ref2->ref && TREE_CODE (ref2->ref) == TARGET_MEM_REF)) |
| return true; |
| |
| /* Dispatch to the pointer-vs-decl or pointer-vs-pointer disambiguators. */ |
| set = tbaa_p ? -1 : 0; |
| if (var1_p && ind2_p) |
| return indirect_ref_may_alias_decl_p (ref2->ref, TREE_OPERAND (base2, 0), |
| offset2, max_size2, |
| ao_ref_alias_set (ref2), set, |
| ref1->ref, base1, |
| offset1, max_size1, |
| ao_ref_alias_set (ref1), set); |
| else if (ind1_p && ind2_p) |
| return indirect_refs_may_alias_p (ref1->ref, TREE_OPERAND (base1, 0), |
| offset1, max_size1, |
| ao_ref_alias_set (ref1), set, |
| ref2->ref, TREE_OPERAND (base2, 0), |
| offset2, max_size2, |
| ao_ref_alias_set (ref2), set); |
| |
| gcc_unreachable (); |
| } |
| |
| 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; |
| |
| /* 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 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: |
| { |
| 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_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 builtins do not read from memory. */ |
| case BUILT_IN_FREE: |
| case BUILT_IN_MALLOC: |
| case BUILT_IN_CALLOC: |
| case BUILT_IN_MEMSET: |
| 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: |
| return false; |
| |
| default: |
| /* Fallthru to general call handling. */; |
| } |
| |
| /* Check if base is a global static variable that is not read |
| by the function. */ |
| if (TREE_CODE (base) == VAR_DECL |
| && TREE_STATIC (base) |
| && !TREE_PUBLIC (base)) |
| { |
| bitmap not_read; |
| |
| if (callee != NULL_TREE |
| && (not_read |
| = ipa_reference_get_not_read_global (cgraph_node (callee))) |
| && bitmap_bit_p (not_read, DECL_UID (base))) |
| goto process_args; |
| } |
| |
| /* If the base variable is call-used or call-clobbered then |
| it may be used. */ |
| if (flags & (ECF_PURE|ECF_CONST|ECF_LOOPING_CONST_OR_PURE|ECF_NOVOPS)) |
| { |
| if (DECL_P (base)) |
| { |
| if (is_call_used (base)) |
| return true; |
| } |
| else if (INDIRECT_REF_P (base) |
| && 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_solution_includes_global (&pi->pt) |
| || pt_solutions_intersect (&cfun->gimple_df->callused, &pi->pt) |
| || pt_solutions_intersect (&cfun->gimple_df->escaped, &pi->pt)) |
| return true; |
| } |
| else |
| return true; |
| } |
| else |
| { |
| if (DECL_P (base)) |
| { |
| if (is_call_clobbered (base)) |
| return true; |
| } |
| else if (INDIRECT_REF_P (base) |
| && 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_solution_includes_global (&pi->pt) |
| || pt_solutions_intersect (&cfun->gimple_df->escaped, &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); |
| |
| 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); |
| |
| 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; |
| |
| /* 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: |
| { |
| 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, 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: |
| /* Unix98 specifies that errno is set on allocation failure. |
| Until we properly can track the errno location assume it |
| is not a local decl but external or anonymous storage in |
| a different translation unit. Also assume it is of |
| type int as required by the standard. */ |
| if (flag_errno_math |
| && TREE_TYPE (base) == integer_type_node) |
| { |
| struct ptr_info_def *pi; |
| if (DECL_P (base) |
| && !TREE_STATIC (base)) |
| return true; |
| else if (INDIRECT_REF_P (base) |
| && TREE_CODE (TREE_OPERAND (base, 0)) == SSA_NAME |
| && (pi = SSA_NAME_PTR_INFO (TREE_OPERAND (base, 0)))) |
| return pi->pt.anything || pi->pt.nonlocal; |
| } |
| 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: |
| { |
| 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)); |
| } |
| 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) |
| && !TREE_PUBLIC (base)) |
| { |
| bitmap not_written; |
| |
| if ((not_written |
| = ipa_reference_get_not_written_global (cgraph_node (callee))) |
| && bitmap_bit_p (not_written, DECL_UID (base))) |
| return false; |
| } |
| |
| if (DECL_P (base)) |
| return is_call_clobbered (base); |
| else if (INDIRECT_REF_P (base) |
| && 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_solution_includes_global (&pi->pt) |
| || pt_solutions_intersect (&cfun->gimple_df->escaped, &pi->pt)); |
| } |
| |
| return true; |
| } |
| |
| static bool ATTRIBUTE_UNUSED |
| 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 |
| && !is_gimple_reg (lhs)) |
| { |
| 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 (!is_gimple_reg (lhs)) |
| { |
| ao_ref r; |
| ao_ref_init (&r, gimple_assign_lhs (stmt)); |
| 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); |
| } |
| |
| |
| /* 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, bitmap *visited) |
| { |
| 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 true; |
| vuse = get_continuation_for_phi (def_stmt, ref, visited); |
| if (!vuse) |
| return false; |
| continue; |
| } |
| /* A clobbering statement or the end of the IL ends it failing. */ |
| else if (gimple_nop_p (def_stmt) |
| || stmt_may_clobber_ref_p_1 (def_stmt, ref)) |
| return false; |
| vuse = gimple_vuse (def_stmt); |
| } |
| return true; |
| } |
| |
| /* 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. Returns NULL_TREE if no suitable virtual operand can |
| be found. */ |
| |
| tree |
| get_continuation_for_phi (gimple phi, ao_ref *ref, bitmap *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 arguments try to skip non-aliasing code until we hit |
| the phi argument definition that dominates the other one. */ |
| if (nargs == 2) |
| { |
| tree arg0 = PHI_ARG_DEF (phi, 0); |
| tree arg1 = PHI_ARG_DEF (phi, 1); |
| 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, 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, 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)) |
| { |
| if (!stmt_may_clobber_ref_p_1 (def0, ref) |
| && !stmt_may_clobber_ref_p_1 (def1, ref)) |
| return common_vuse; |
| } |
| } |
| |
| 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, void *), |
| void *(*translate)(ao_ref *, tree, void *), void *data) |
| { |
| bitmap visited = NULL; |
| void *res; |
| |
| 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, data); |
| if (res) |
| 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, &visited); |
| else |
| { |
| 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. */ |
| } |
| 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; |
| } |
| |