From d01bf29c8df234a67748d0110d76735839ed139d Mon Sep 17 00:00:00 2001 From: Matthias Braun Date: Sun, 9 Mar 2008 18:21:26 +0000 Subject: [PATCH] - rewrite and cleanup of memory disambiguator code, should also catch a few more cases now that were buggy before [r18027] --- ir/ana/irmemory.c | 422 +++++++++++++++------------------------------- 1 file changed, 132 insertions(+), 290 deletions(-) diff --git a/ir/ana/irmemory.c b/ir/ana/irmemory.c index 4dd47ba35..36b727f47 100644 --- a/ir/ana/irmemory.c +++ b/ir/ana/irmemory.c @@ -380,90 +380,14 @@ static ir_alias_relation different_types(ir_node *adr1, ir_node *adr2) return may_alias; } /* different_types */ -/** - * Check if an offset is a constant and these constant is bigger or equal - * than a given size. - */ -static int check_const_offset(ir_node *offset, int size) { - ir_mode *mode = get_irn_mode(offset); - - /* ok, we found an offset, check for constant */ - if (is_Const(offset) && mode_is_int(mode)) { - tarval *tv = new_tarval_from_long(size, mode); - - /* size <= offset ? */ - if (tarval_cmp(tv, get_Const_tarval(offset)) & (pn_Cmp_Eq|pn_Cmp_Lt)) - return 1; - } - return 0; -} /* check_const_offset */ - -/** - * Check if we can determine that the two pointers always have an offset bigger - * than size. - */ -static ir_alias_relation _different_pointer(ir_node *adr1, ir_node *adr2, int size) { - int found = 0; - - if (is_Add(adr1)) { - /* first address is the result of a pointer addition */ - ir_node *l1 = get_Add_left(adr1); - ir_node *r1 = get_Add_right(adr1); - - if (l1 == adr2) { - found = check_const_offset(r1, size); - } else if (r1 == adr2) { - found = check_const_offset(l1, size); - } else if (is_Add(adr2)) { - /* second address is the result of a pointer addition */ - ir_node *l2 = get_Add_left(adr2); - ir_node *r2 = get_Add_right(adr2); - - if (l1 == l2) { - return _different_pointer(r1, r2, size); - } else if (l1 == r2) { - return _different_pointer(r1, l2, size); - } else if (r1 == l2) { - return _different_pointer(l1, r2, size); - } else if (r1 == r2) { - return _different_pointer(l1, l2, size); - } - } - } else if (is_Add(adr2)) { - /* second address is the result of a pointer addition */ - ir_node *l2 = get_Add_left(adr2); - ir_node *r2 = get_Add_right(adr2); - - if (l2 == adr1) { - found = check_const_offset(r2, size); - } else if (r2 == adr1) { - found = check_const_offset(l2, size); - } - } else { - return different_index(adr1, adr2, size); - } - return found ? no_alias : may_alias; -} /* _different_pointer */ - -/** - * Check if we can determine that the two pointers always have an offset bigger - * then the maximum size of mode1, mode2 - */ -static ir_alias_relation different_pointer(ir_node *adr1, ir_mode *mode1, ir_node *adr2, ir_mode *mode2) { - int size = get_mode_size_bytes(mode1); - int n = get_mode_size_bytes(mode2); - - if (n > size) - size = n; - return _different_pointer(adr1, adr2, size); -} /* different_pointer */ - /** * Returns non-zero if a node is a routine parameter. * * @param node the Proj node to test */ static int is_arg_Proj(ir_node *node) { + if (! is_Proj(node)) + return 0; node = get_Proj_pred(node); if (! is_Proj(node)) return 0; @@ -502,6 +426,47 @@ static INLINE int is_global_var(ir_node *irn) { return is_SymConst_addr_ent(irn); } /* is_global_var */ +/** + * classify storage locations. + * Except STORAGE_CLASS_POINTER they are all disjoint. + * STORAGE_CLASS_POINTER potentially aliases all classes which don't have a + * NOTTAKEN modifier. + */ +typedef enum { + STORAGE_CLASS_POINTER = 0x0000, + STORAGE_CLASS_GLOBALVAR = 0x0001, + STORAGE_CLASS_LOCALVAR = 0x0002, + STORAGE_CLASS_ARGUMENT = 0x0003, + STORAGE_CLASS_TLS = 0x0004, + STORAGE_CLASS_MALLOCED = 0x0005, + + STORAGE_CLASS_MODIFIER_NOTTAKEN = 0x1000, +} storage_class_class_t; + +static storage_class_class_t classify_pointer(ir_graph *irg, ir_node *irn) +{ + if(is_SymConst_addr_ent(irn)) { + ir_entity *entity = get_SymConst_entity(irn); + storage_class_class_t res = STORAGE_CLASS_GLOBALVAR; + if (get_entity_address_taken(entity) == ir_address_not_taken) { + res |= STORAGE_CLASS_MODIFIER_NOTTAKEN; + } + return res; + } else if(irn == get_irg_frame(irg)) { + /* TODO: we already skipped sels so we can't determine address_taken */ + return STORAGE_CLASS_LOCALVAR; + } else if(is_arg_Proj(irn)) { + return STORAGE_CLASS_ARGUMENT; + } else if(irn == get_irg_tls(irg)) { + /* TODO: we already skipped sels so we can't determine address_taken */ + return STORAGE_CLASS_TLS; + } else if (is_Proj(irn) && is_malloc_Result(irn)) { + return STORAGE_CLASS_MALLOCED; + } + + return STORAGE_CLASS_POINTER; +} + /** * Determine the alias relation between two addresses. */ @@ -510,10 +475,17 @@ static ir_alias_relation _get_alias_relation( ir_node *adr1, ir_mode *mode1, ir_node *adr2, ir_mode *mode2) { - ir_opcode op1, op2; - ir_entity *ent1, *ent2; - unsigned options; - ir_alias_relation rel; + ir_entity *ent1, *ent2; + unsigned options; + long offset1 = 0; + long offset2 = 0; + ir_node *base1; + ir_node *base2; + ir_node *orig_adr1 = adr1; + ir_node *orig_adr2 = adr2; + unsigned mode_size; + storage_class_class_t class1; + storage_class_class_t class2; if (! get_opt_alias_analysis()) return may_alias; @@ -527,225 +499,95 @@ static ir_alias_relation _get_alias_relation( if (options & aa_opt_no_alias) return no_alias; - /* Two save some code, sort the addresses by its id's. Beware, this - might break some things, so better check here. */ - assert(iro_SymConst < iro_Sel && iro_Sel < iro_Proj && "Code dependence broken"); - op1 = get_irn_opcode(adr1); - op2 = get_irn_opcode(adr2); + /* do the addresses have constants offsets? + * Note: nodes are normalized to have constants at right inputs, + * sub X, C is normalized to add X, -C + * */ + while (is_Add(adr1)) { + ir_node *add_right = get_Add_right(adr1); + if (is_Const(add_right)) { + tarval *tv = get_Const_tarval(add_right); + offset1 += get_tarval_long(tv); + adr1 = get_Add_left(adr1); + continue; + } + break; + } + while (is_Add(adr2)) { + ir_node *add_right = get_Add_right(adr2); + if (is_Const(add_right)) { + tarval *tv = get_Const_tarval(add_right); + offset2 += get_tarval_long(tv); + adr2 = get_Add_left(adr2); + continue; + } + break; + } - if (op1 > op2) { - ir_node *t = adr1; - ir_mode *m = mode1; - adr1 = adr2; - mode1 = mode2; - adr2 = t; - mode2 = m; + mode_size = get_mode_size_bytes(mode1); + if (get_mode_size_bytes(mode2) > mode_size) { + mode_size = get_mode_size_bytes(mode2); } - /* some pointers, check if they have the same base but different offset */ - rel = different_pointer(adr1, mode1, adr2, mode2); - if (rel != may_alias) - return rel; + /* same base address -> compare offsets */ + if (adr1 == adr2) { + if(labs(offset2 - offset1) >= mode_size) + return no_alias; + else + return sure_alias; + } - if (is_global_var(adr1)) { - /* first address is a global variable */ + /* skip sels */ + base1 = adr1; + base2 = adr2; + if (is_Sel(adr1)) { + adr1 = find_base_adr(adr1, &ent1); + } + if (is_Sel(adr2)) { + adr2 = find_base_adr(adr2, &ent2); + } - if (is_global_var(adr2)) { - /* both addresses are global variables and we know - they are different (R1 a) */ - if (get_SymConst_entity(adr1) != get_SymConst_entity(adr2)) - return no_alias; - else { - /* equal entity addresses */ - return sure_alias; - } - } else if (is_Sel(adr2)) { - ir_node *base2 = find_base_adr(adr2, &ent2); + /* same base address -> compare sel entities*/ + if (adr1 == adr2 && base1 != adr1 && base2 != adr2) { + if (ent1 != ent2) + return no_alias; + else + return different_sel_offsets(base1, base2); + } - if (is_global_var(base2)) { - /* base2 address is a global var (R1 a) */ - if (adr1 != base2) - return no_alias; - } else if (base2 == get_irg_frame(irg)) { - /* the second one is a local variable so they are always - different (R1 b) */ - return no_alias; - } else if (base2 == get_irg_tls(irg)) { - /* the second one is a TLS variable so they are always - different (R1 c) */ - return no_alias; - } else if (is_Proj(base2)) { - if (is_malloc_Result(base2)) { - /* the second one is an offset from a result of a malloc like call, ie. - freshly allocated non-aliases heap memory, (R1 f) */ - return no_alias; - } - } - } else if (is_Proj(adr2)) { - if (is_malloc_Result(adr2)) { - /* the second one is a result of a malloc like call, ie. - freshly allocated non-aliases heap memory, (R1 f) */ - return no_alias; - } - } + class1 = classify_pointer(irg, adr1); + class2 = classify_pointer(irg, adr2); - /* Here we are: the first is a global var, the second some pointer. */ - ent1 = get_SymConst_entity(adr1); - if (get_entity_address_taken(ent1) == ir_address_not_taken) { - /* The address of the global variable was never taken, so - the pointer cannot match (R2). */ + if (class1 == STORAGE_CLASS_POINTER) { + if (class2 & STORAGE_CLASS_MODIFIER_NOTTAKEN) { return no_alias; + } else { + return may_alias; } - } else if (is_Sel(adr1)) { - /* the first address is a Sel */ - ir_node *base1 = find_base_adr(adr1, &ent1); - - if (base1 == get_irg_frame(irg)) { - /* first is a local variable ent1 */ - if (is_Sel(adr2)) { - /* the second address is a Sel */ - ir_node *base2 = find_base_adr(adr2, &ent2); - - if (base1 == base2) { - /* identical bases: both are local variables */ - if (ent1 != ent2) { - /* both addresses are local variables and we know - they are different (R1 a) */ - return no_alias; - } else { - /* same local var */ - return different_sel_offsets(adr1, adr2); - } - } else if (base2 == get_irg_tls(irg)) { - /* the second one is a TLS variable so they are always - different (R1 d) */ - return no_alias; - } else if (is_Proj(base2)) { - if (is_arg_Proj(base2)) { - /* the second one is an offset from a parameter so they are - always different (R1 e) */ - return no_alias; - } else if (is_malloc_Result(base2)) { - /* the second one is an offset from a result of a malloc like call, ie. - freshly allocated non-aliases heap memory (R1 g) */ - return no_alias; - } - } - } else if (is_Proj(adr2)) { - if (is_arg_Proj(adr2)) { - /* a local variable and a parameter are always different (R1 e) */ - return no_alias; - } else if (is_malloc_Result(adr2)) { - /* the second one is a result of a malloc like call, ie. - freshly allocated non-aliases heap memory (R1 g) */ - return no_alias; - } - } - } else if (base1 == get_irg_tls(irg)) { - /* the first is a TLS variable */ - if (is_Sel(adr2)) { - /* the second address is a Sel */ - ir_node *base2 = find_base_adr(adr2, &ent2); - - if (base1 == base2) { - if (ent1 != ent2) { - /* both addresses are tls variables and we know - they are different (R1 a) */ - return no_alias; - } else { - /* same tls var */ - return different_sel_offsets(adr1, adr2); - } - } else if (base2 == get_irg_frame(irg)) { - /* the first one is a tls variable, the second a local one, - they are different (R1 d) */ - return no_alias; - } else if (is_Proj(base2)) { - if (is_malloc_Result(base2)) { - /* the second one is an offset from a result of a malloc like call, ie. - freshly allocated non-aliases heap memory (R1 h) */ - return no_alias; - } - } - } else if (is_Proj(adr2)) { - if (is_malloc_Result(adr2)) { - /* the second one is an offset from a result of a malloc like call, ie. - freshly allocated non-aliases heap memory (R1 h) */ - return no_alias; - } - } - } else if (is_Proj(base1)) { - if (is_arg_Proj(base1)) { - /* the first one is an offset from a parameter */ - if (is_Sel(adr2)) { - /* the second address is a Sel */ - ir_node *base2 = find_base_adr(adr2, &ent2); - - if (base2 == get_irg_frame(irg)) { - /* the second one is a local variable so they are always - different (R1 e) */ - return no_alias; - } else if (is_Proj(base2)) { - if (is_malloc_Result(base2)) { - /* the second one is an offset from a result of a malloc like call, ie. - freshly allocated non-aliases heap memory (R1 í) */ - return no_alias; - } - } - } else if (is_Proj(adr2)) { - if (is_malloc_Result(adr2)) { - /* the second one is a malloc like call, ie. - freshly allocated non-aliases heap memory (R1 í) */ - return no_alias; - } - } - } - } else if (is_global_var(base1)) { - /* the first one is an offset from a global variable */ - ent1 = get_SymConst_entity(base1); - if (is_Sel(adr2)) { - /* the second address is a Sel */ - ir_node *base2 = find_base_adr(adr2, &ent2); - - if (base1 == base2) { - /* same global var */ - return different_sel_offsets(adr1, adr2); - } else if (base2 == get_irg_frame(irg)) { - /* the second one is a local variable so they are always - different (R1 a) */ - return no_alias; - } else if (base2 == get_irg_tls(irg)) { - /* the second one is a TLS variable so they are always - different (R1 a) */ - return no_alias; - } else if (is_Proj(base2)) { - if (is_arg_Proj(base2)) { - if (get_entity_address_taken(ent1) == ir_address_not_taken) { - /* The address of the global variable was never taken, so - the pointer cannot match (R2). */ - return no_alias; - } - } else if (is_malloc_Result(base2)) { - /* the second one is an offset from a result of a malloc like call, ie. - freshly allocated non-aliases heap memory (R1 g) */ - return no_alias; - } - } else if (is_global_var(base2)) { - ent2 = get_SymConst_entity(base2); - /* both addresses are global variables and we know - they are different (R1 a) */ - if (ent1 != ent2) - return no_alias; - } - } + } else if (class2 == STORAGE_CLASS_POINTER) { + if (class1 & STORAGE_CLASS_MODIFIER_NOTTAKEN) { + return no_alias; + } else { + return may_alias; } - } else { - /* Note: we cannot check for malloc result here, as we cannot be sure - * the result is not stored anywhere after getting if. - */ } - if (options & aa_opt_type_based) { /* Type based alias analysis */ + if (class1 != class2) { + return no_alias; + } + + if (class1 == STORAGE_CLASS_GLOBALVAR) { + ir_entity *entity1 = get_SymConst_entity(adr1); + ir_entity *entity2 = get_SymConst_entity(adr2); + if(entity1 != entity2) + return no_alias; + + /* for some reason CSE didn't work for the 2 symconsts... */ + return may_alias; + } + + /* Type based alias analysis */ + if (options & aa_opt_type_based) { ir_alias_relation rel; if (options & aa_opt_byte_type_may_alias) { @@ -772,7 +614,7 @@ leave_type_based_alias:; /* do we have a language specific memory disambiguator? */ if (language_disambuigator) { - ir_alias_relation rel = (*language_disambuigator)(irg, adr1, mode1, adr2, mode2); + ir_alias_relation rel = (*language_disambuigator)(irg, orig_adr1, mode1, orig_adr2, mode2); if (rel != may_alias) return rel; } -- 2.20.1