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[/] [openrisc/] [trunk/] [gnu-dev/] [or1k-gcc/] [gcc/] [tree-ssa-strlen.c] - Rev 772
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/* String length optimization Copyright (C) 2011 Free Software Foundation, Inc. Contributed by Jakub Jelinek <jakub@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 "tree-flow.h" #include "tree-pass.h" #include "domwalk.h" #include "alloc-pool.h" #include "tree-ssa-propagate.h" #include "gimple-pretty-print.h" #include "params.h" #include "expr.h" /* A vector indexed by SSA_NAME_VERSION. 0 means unknown, positive value is an index into strinfo vector, negative value stands for string length of a string literal (~strlen). */ static VEC (int, heap) *ssa_ver_to_stridx; /* Number of currently active string indexes plus one. */ static int max_stridx; /* String information record. */ typedef struct strinfo_struct { /* String length of this string. */ tree length; /* Any of the corresponding pointers for querying alias oracle. */ tree ptr; /* Statement for delayed length computation. */ gimple stmt; /* Pointer to '\0' if known, if NULL, it can be computed as ptr + length. */ tree endptr; /* Reference count. Any changes to strinfo entry possibly shared with dominating basic blocks need unshare_strinfo first, except for dont_invalidate which affects only the immediately next maybe_invalidate. */ int refcount; /* Copy of index. get_strinfo (si->idx) should return si; */ int idx; /* These 3 fields are for chaining related string pointers together. E.g. for bl = strlen (b); dl = strlen (d); strcpy (a, b); c = a + bl; strcpy (c, d); e = c + dl; strinfo(a) -> strinfo(c) -> strinfo(e) All have ->first field equal to strinfo(a)->idx and are doubly chained through prev/next fields. The later strinfos are required to point into the same string with zero or more bytes after the previous pointer and all bytes in between the two pointers must be non-zero. Functions like strcpy or memcpy are supposed to adjust all previous strinfo lengths, but not following strinfo lengths (those are uncertain, usually invalidated during maybe_invalidate, except when the alias oracle knows better). Functions like strcat on the other side adjust the whole related strinfo chain. They are updated lazily, so to use the chain the same first fields and si->prev->next == si->idx needs to be verified. */ int first; int next; int prev; /* A flag whether the string is known to be written in the current function. */ bool writable; /* A flag for the next maybe_invalidate that this strinfo shouldn't be invalidated. Always cleared by maybe_invalidate. */ bool dont_invalidate; } *strinfo; DEF_VEC_P(strinfo); DEF_VEC_ALLOC_P(strinfo,heap); /* Pool for allocating strinfo_struct entries. */ static alloc_pool strinfo_pool; /* Vector mapping positive string indexes to strinfo, for the current basic block. The first pointer in the vector is special, it is either NULL, meaning the vector isn't shared, or it is a basic block pointer to the owner basic_block if shared. If some other bb wants to modify the vector, the vector needs to be unshared first, and only the owner bb is supposed to free it. */ static VEC(strinfo, heap) *stridx_to_strinfo; /* One OFFSET->IDX mapping. */ struct stridxlist { struct stridxlist *next; HOST_WIDE_INT offset; int idx; }; /* Hash table entry, mapping a DECL to a chain of OFFSET->IDX mappings. */ struct decl_stridxlist_map { struct tree_map_base base; struct stridxlist list; }; /* Hash table for mapping decls to a chained list of offset -> idx mappings. */ static htab_t decl_to_stridxlist_htab; /* Obstack for struct stridxlist and struct decl_stridxlist_map. */ static struct obstack stridx_obstack; /* Last memcpy statement if it could be adjusted if the trailing '\0' written is immediately overwritten, or *x = '\0' store that could be removed if it is immediately overwritten. */ struct laststmt_struct { gimple stmt; tree len; int stridx; } laststmt; /* Hash a from tree in a decl_stridxlist_map. */ static unsigned int decl_to_stridxlist_hash (const void *item) { return DECL_UID (((const struct decl_stridxlist_map *) item)->base.from); } /* Helper function for get_stridx. */ static int get_addr_stridx (tree exp) { HOST_WIDE_INT off; struct decl_stridxlist_map ent, *e; struct stridxlist *list; tree base; if (decl_to_stridxlist_htab == NULL) return 0; base = get_addr_base_and_unit_offset (exp, &off); if (base == NULL || !DECL_P (base)) return 0; ent.base.from = base; e = (struct decl_stridxlist_map *) htab_find_with_hash (decl_to_stridxlist_htab, &ent, DECL_UID (base)); if (e == NULL) return 0; list = &e->list; do { if (list->offset == off) return list->idx; list = list->next; } while (list); return 0; } /* Return string index for EXP. */ static int get_stridx (tree exp) { tree s, o; if (TREE_CODE (exp) == SSA_NAME) return VEC_index (int, ssa_ver_to_stridx, SSA_NAME_VERSION (exp)); if (TREE_CODE (exp) == ADDR_EXPR) { int idx = get_addr_stridx (TREE_OPERAND (exp, 0)); if (idx != 0) return idx; } s = string_constant (exp, &o); if (s != NULL_TREE && (o == NULL_TREE || host_integerp (o, 0)) && TREE_STRING_LENGTH (s) > 0) { HOST_WIDE_INT offset = o ? tree_low_cst (o, 0) : 0; const char *p = TREE_STRING_POINTER (s); int max = TREE_STRING_LENGTH (s) - 1; if (p[max] == '\0' && offset >= 0 && offset <= max) return ~(int) strlen (p + offset); } return 0; } /* Return true if strinfo vector is shared with the immediate dominator. */ static inline bool strinfo_shared (void) { return VEC_length (strinfo, stridx_to_strinfo) && VEC_index (strinfo, stridx_to_strinfo, 0) != NULL; } /* Unshare strinfo vector that is shared with the immediate dominator. */ static void unshare_strinfo_vec (void) { strinfo si; unsigned int i = 0; gcc_assert (strinfo_shared ()); stridx_to_strinfo = VEC_copy (strinfo, heap, stridx_to_strinfo); for (i = 1; VEC_iterate (strinfo, stridx_to_strinfo, i, si); ++i) if (si != NULL) si->refcount++; VEC_replace (strinfo, stridx_to_strinfo, 0, NULL); } /* Attempt to create a string index for exp, ADDR_EXPR's operand. Return a pointer to the location where the string index can be stored (if 0) or is stored, or NULL if this can't be tracked. */ static int * addr_stridxptr (tree exp) { void **slot; struct decl_stridxlist_map ent; struct stridxlist *list; HOST_WIDE_INT off; tree base = get_addr_base_and_unit_offset (exp, &off); if (base == NULL_TREE || !DECL_P (base)) return NULL; if (decl_to_stridxlist_htab == NULL) { decl_to_stridxlist_htab = htab_create (64, decl_to_stridxlist_hash, tree_map_base_eq, NULL); gcc_obstack_init (&stridx_obstack); } ent.base.from = base; slot = htab_find_slot_with_hash (decl_to_stridxlist_htab, &ent, DECL_UID (base), INSERT); if (*slot) { int i; list = &((struct decl_stridxlist_map *)*slot)->list; for (i = 0; i < 16; i++) { if (list->offset == off) return &list->idx; if (list->next == NULL) break; } if (i == 16) return NULL; list->next = XOBNEW (&stridx_obstack, struct stridxlist); list = list->next; } else { struct decl_stridxlist_map *e = XOBNEW (&stridx_obstack, struct decl_stridxlist_map); e->base.from = base; *slot = (void *) e; list = &e->list; } list->next = NULL; list->offset = off; list->idx = 0; return &list->idx; } /* Create a new string index, or return 0 if reached limit. */ static int new_stridx (tree exp) { int idx; if (max_stridx >= PARAM_VALUE (PARAM_MAX_TRACKED_STRLENS)) return 0; if (TREE_CODE (exp) == SSA_NAME) { if (SSA_NAME_OCCURS_IN_ABNORMAL_PHI (exp)) return 0; idx = max_stridx++; VEC_replace (int, ssa_ver_to_stridx, SSA_NAME_VERSION (exp), idx); return idx; } if (TREE_CODE (exp) == ADDR_EXPR) { int *pidx = addr_stridxptr (TREE_OPERAND (exp, 0)); if (pidx != NULL) { gcc_assert (*pidx == 0); *pidx = max_stridx++; return *pidx; } } return 0; } /* Like new_stridx, but for ADDR_EXPR's operand instead. */ static int new_addr_stridx (tree exp) { int *pidx; if (max_stridx >= PARAM_VALUE (PARAM_MAX_TRACKED_STRLENS)) return 0; pidx = addr_stridxptr (exp); if (pidx != NULL) { gcc_assert (*pidx == 0); *pidx = max_stridx++; return *pidx; } return 0; } /* Create a new strinfo. */ static strinfo new_strinfo (tree ptr, int idx, tree length) { strinfo si = (strinfo) pool_alloc (strinfo_pool); si->length = length; si->ptr = ptr; si->stmt = NULL; si->endptr = NULL_TREE; si->refcount = 1; si->idx = idx; si->first = 0; si->prev = 0; si->next = 0; si->writable = false; si->dont_invalidate = false; return si; } /* Decrease strinfo refcount and free it if not referenced anymore. */ static inline void free_strinfo (strinfo si) { if (si && --si->refcount == 0) pool_free (strinfo_pool, si); } /* Return strinfo vector entry IDX. */ static inline strinfo get_strinfo (int idx) { if (VEC_length (strinfo, stridx_to_strinfo) <= (unsigned int) idx) return NULL; return VEC_index (strinfo, stridx_to_strinfo, idx); } /* Set strinfo in the vector entry IDX to SI. */ static inline void set_strinfo (int idx, strinfo si) { if (VEC_length (strinfo, stridx_to_strinfo) && VEC_index (strinfo, stridx_to_strinfo, 0)) unshare_strinfo_vec (); if (VEC_length (strinfo, stridx_to_strinfo) <= (unsigned int) idx) VEC_safe_grow_cleared (strinfo, heap, stridx_to_strinfo, idx + 1); VEC_replace (strinfo, stridx_to_strinfo, idx, si); } /* Return string length, or NULL if it can't be computed. */ static tree get_string_length (strinfo si) { if (si->length) return si->length; if (si->stmt) { gimple stmt = si->stmt, lenstmt; tree callee, lhs, lhs_var, fn, tem; location_t loc; gimple_stmt_iterator gsi; gcc_assert (is_gimple_call (stmt)); callee = gimple_call_fndecl (stmt); gcc_assert (callee && DECL_BUILT_IN_CLASS (callee) == BUILT_IN_NORMAL); lhs = gimple_call_lhs (stmt); gcc_assert (builtin_decl_implicit_p (BUILT_IN_STPCPY)); /* unshare_strinfo is intentionally not called here. The (delayed) transformation of strcpy or strcat into stpcpy is done at the place of the former strcpy/strcat call and so can affect all the strinfos with the same stmt. If they were unshared before and transformation has been already done, the handling of BUILT_IN_STPCPY{,_CHK} should just compute the right length. */ switch (DECL_FUNCTION_CODE (callee)) { case BUILT_IN_STRCAT: case BUILT_IN_STRCAT_CHK: gsi = gsi_for_stmt (stmt); fn = builtin_decl_implicit (BUILT_IN_STRLEN); gcc_assert (lhs == NULL_TREE); lhs_var = create_tmp_var (TREE_TYPE (TREE_TYPE (fn)), NULL); add_referenced_var (lhs_var); tem = unshare_expr (gimple_call_arg (stmt, 0)); lenstmt = gimple_build_call (fn, 1, tem); lhs = make_ssa_name (lhs_var, lenstmt); gimple_call_set_lhs (lenstmt, lhs); gimple_set_vuse (lenstmt, gimple_vuse (stmt)); gsi_insert_before (&gsi, lenstmt, GSI_SAME_STMT); lhs_var = create_tmp_var (TREE_TYPE (gimple_call_arg (stmt, 0)), NULL); add_referenced_var (lhs_var); tem = gimple_call_arg (stmt, 0); lenstmt = gimple_build_assign_with_ops (POINTER_PLUS_EXPR, make_ssa_name (lhs_var, NULL), tem, lhs); gsi_insert_before (&gsi, lenstmt, GSI_SAME_STMT); gimple_call_set_arg (stmt, 0, gimple_assign_lhs (lenstmt)); lhs = NULL_TREE; /* FALLTHRU */ case BUILT_IN_STRCPY: case BUILT_IN_STRCPY_CHK: if (gimple_call_num_args (stmt) == 2) fn = builtin_decl_implicit (BUILT_IN_STPCPY); else fn = builtin_decl_explicit (BUILT_IN_STPCPY_CHK); gcc_assert (lhs == NULL_TREE); if (dump_file && (dump_flags & TDF_DETAILS) != 0) { fprintf (dump_file, "Optimizing: "); print_gimple_stmt (dump_file, stmt, 0, TDF_SLIM); } gimple_call_set_fndecl (stmt, fn); lhs_var = create_tmp_var (TREE_TYPE (TREE_TYPE (fn)), NULL); add_referenced_var (lhs_var); lhs = make_ssa_name (lhs_var, stmt); gimple_call_set_lhs (stmt, lhs); update_stmt (stmt); if (dump_file && (dump_flags & TDF_DETAILS) != 0) { fprintf (dump_file, "into: "); print_gimple_stmt (dump_file, stmt, 0, TDF_SLIM); } /* FALLTHRU */ case BUILT_IN_STPCPY: case BUILT_IN_STPCPY_CHK: gcc_assert (lhs != NULL_TREE); loc = gimple_location (stmt); si->endptr = lhs; si->stmt = NULL; lhs = fold_convert_loc (loc, size_type_node, lhs); si->length = fold_convert_loc (loc, size_type_node, si->ptr); si->length = fold_build2_loc (loc, MINUS_EXPR, size_type_node, lhs, si->length); break; default: gcc_unreachable (); break; } } return si->length; } /* Invalidate string length information for strings whose length might change due to stores in stmt. */ static bool maybe_invalidate (gimple stmt) { strinfo si; unsigned int i; bool nonempty = false; for (i = 1; VEC_iterate (strinfo, stridx_to_strinfo, i, si); ++i) if (si != NULL) { if (!si->dont_invalidate) { ao_ref r; ao_ref_init_from_ptr_and_size (&r, si->ptr, NULL_TREE); if (stmt_may_clobber_ref_p_1 (stmt, &r)) { set_strinfo (i, NULL); free_strinfo (si); continue; } } si->dont_invalidate = false; nonempty = true; } return nonempty; } /* Unshare strinfo record SI, if it has recount > 1 or if stridx_to_strinfo vector is shared with some other bbs. */ static strinfo unshare_strinfo (strinfo si) { strinfo nsi; if (si->refcount == 1 && !strinfo_shared ()) return si; nsi = new_strinfo (si->ptr, si->idx, si->length); nsi->stmt = si->stmt; nsi->endptr = si->endptr; nsi->first = si->first; nsi->prev = si->prev; nsi->next = si->next; nsi->writable = si->writable; set_strinfo (si->idx, nsi); free_strinfo (si); return nsi; } /* Return first strinfo in the related strinfo chain if all strinfos in between belong to the chain, otherwise NULL. */ static strinfo verify_related_strinfos (strinfo origsi) { strinfo si = origsi, psi; if (origsi->first == 0) return NULL; for (; si->prev; si = psi) { if (si->first != origsi->first) return NULL; psi = get_strinfo (si->prev); if (psi == NULL) return NULL; if (psi->next != si->idx) return NULL; } if (si->idx != si->first) return NULL; return si; } /* Note that PTR, a pointer SSA_NAME initialized in the current stmt, points to a zero-length string and if possible chain it to a related strinfo chain whose part is or might be CHAINSI. */ static strinfo zero_length_string (tree ptr, strinfo chainsi) { strinfo si; int idx; gcc_checking_assert (TREE_CODE (ptr) == SSA_NAME && get_stridx (ptr) == 0); if (SSA_NAME_OCCURS_IN_ABNORMAL_PHI (ptr)) return NULL; if (chainsi != NULL) { si = verify_related_strinfos (chainsi); if (si) { chainsi = si; for (; chainsi->next; chainsi = si) { if (chainsi->endptr == NULL_TREE) { chainsi = unshare_strinfo (chainsi); chainsi->endptr = ptr; } si = get_strinfo (chainsi->next); if (si == NULL || si->first != chainsi->first || si->prev != chainsi->idx) break; } gcc_assert (chainsi->length || chainsi->stmt); if (chainsi->endptr == NULL_TREE) { chainsi = unshare_strinfo (chainsi); chainsi->endptr = ptr; } if (chainsi->length && integer_zerop (chainsi->length)) { if (chainsi->next) { chainsi = unshare_strinfo (chainsi); chainsi->next = 0; } VEC_replace (int, ssa_ver_to_stridx, SSA_NAME_VERSION (ptr), chainsi->idx); return chainsi; } } else if (chainsi->first || chainsi->prev || chainsi->next) { chainsi = unshare_strinfo (chainsi); chainsi->first = 0; chainsi->prev = 0; chainsi->next = 0; } } idx = new_stridx (ptr); if (idx == 0) return NULL; si = new_strinfo (ptr, idx, build_int_cst (size_type_node, 0)); set_strinfo (idx, si); si->endptr = ptr; if (chainsi != NULL) { chainsi = unshare_strinfo (chainsi); if (chainsi->first == 0) chainsi->first = chainsi->idx; chainsi->next = idx; if (chainsi->endptr == NULL_TREE) chainsi->endptr = ptr; si->prev = chainsi->idx; si->first = chainsi->first; si->writable = chainsi->writable; } return si; } /* For strinfo ORIGSI whose length has been just updated update also related strinfo lengths (add ADJ to each, but don't adjust ORIGSI). */ static void adjust_related_strinfos (location_t loc, strinfo origsi, tree adj) { strinfo si = verify_related_strinfos (origsi); if (si == NULL) return; while (1) { strinfo nsi; if (si != origsi) { tree tem; si = unshare_strinfo (si); if (si->length) { tem = fold_convert_loc (loc, TREE_TYPE (si->length), adj); si->length = fold_build2_loc (loc, PLUS_EXPR, TREE_TYPE (si->length), si->length, tem); } else if (si->stmt != NULL) /* Delayed length computation is unaffected. */ ; else gcc_unreachable (); si->endptr = NULL_TREE; si->dont_invalidate = true; } if (si->next == 0) return; nsi = get_strinfo (si->next); if (nsi == NULL || nsi->first != si->first || nsi->prev != si->idx) return; si = nsi; } } /* Find if there are other SSA_NAME pointers equal to PTR for which we don't track their string lengths yet. If so, use IDX for them. */ static void find_equal_ptrs (tree ptr, int idx) { if (TREE_CODE (ptr) != SSA_NAME) return; while (1) { gimple stmt = SSA_NAME_DEF_STMT (ptr); if (!is_gimple_assign (stmt)) return; ptr = gimple_assign_rhs1 (stmt); switch (gimple_assign_rhs_code (stmt)) { case SSA_NAME: break; CASE_CONVERT: if (!POINTER_TYPE_P (TREE_TYPE (ptr))) return; if (TREE_CODE (ptr) == SSA_NAME) break; if (TREE_CODE (ptr) != ADDR_EXPR) return; /* FALLTHRU */ case ADDR_EXPR: { int *pidx = addr_stridxptr (TREE_OPERAND (ptr, 0)); if (pidx != NULL && *pidx == 0) *pidx = idx; return; } default: return; } /* We might find an endptr created in this pass. Grow the vector in that case. */ if (VEC_length (int, ssa_ver_to_stridx) <= SSA_NAME_VERSION (ptr)) VEC_safe_grow_cleared (int, heap, ssa_ver_to_stridx, num_ssa_names); if (VEC_index (int, ssa_ver_to_stridx, SSA_NAME_VERSION (ptr)) != 0) return; VEC_replace (int, ssa_ver_to_stridx, SSA_NAME_VERSION (ptr), idx); } } /* If the last .MEM setter statement before STMT is memcpy (x, y, strlen (y) + 1), the only .MEM use of it is STMT and STMT is known to overwrite x[strlen (x)], adjust the last memcpy to just memcpy (x, y, strlen (y)). SI must be the zero length strinfo. */ static void adjust_last_stmt (strinfo si, gimple stmt, bool is_strcat) { tree vuse, callee, len; struct laststmt_struct last = laststmt; strinfo lastsi, firstsi; laststmt.stmt = NULL; laststmt.len = NULL_TREE; laststmt.stridx = 0; if (last.stmt == NULL) return; vuse = gimple_vuse (stmt); if (vuse == NULL_TREE || SSA_NAME_DEF_STMT (vuse) != last.stmt || !has_single_use (vuse)) return; gcc_assert (last.stridx > 0); lastsi = get_strinfo (last.stridx); if (lastsi == NULL) return; if (lastsi != si) { if (lastsi->first == 0 || lastsi->first != si->first) return; firstsi = verify_related_strinfos (si); if (firstsi == NULL) return; while (firstsi != lastsi) { strinfo nextsi; if (firstsi->next == 0) return; nextsi = get_strinfo (firstsi->next); if (nextsi == NULL || nextsi->prev != firstsi->idx || nextsi->first != si->first) return; firstsi = nextsi; } } if (!is_strcat) { if (si->length == NULL_TREE || !integer_zerop (si->length)) return; } if (is_gimple_assign (last.stmt)) { gimple_stmt_iterator gsi; if (!integer_zerop (gimple_assign_rhs1 (last.stmt))) return; if (stmt_could_throw_p (last.stmt)) return; gsi = gsi_for_stmt (last.stmt); unlink_stmt_vdef (last.stmt); release_defs (last.stmt); gsi_remove (&gsi, true); return; } if (!is_gimple_call (last.stmt)) return; callee = gimple_call_fndecl (last.stmt); if (callee == NULL_TREE || DECL_BUILT_IN_CLASS (callee) != BUILT_IN_NORMAL) return; switch (DECL_FUNCTION_CODE (callee)) { case BUILT_IN_MEMCPY: case BUILT_IN_MEMCPY_CHK: break; default: return; } len = gimple_call_arg (last.stmt, 2); if (host_integerp (len, 1)) { if (!host_integerp (last.len, 1) || integer_zerop (len) || (unsigned HOST_WIDE_INT) tree_low_cst (len, 1) != (unsigned HOST_WIDE_INT) tree_low_cst (last.len, 1) + 1) return; /* Don't adjust the length if it is divisible by 4, it is more efficient to store the extra '\0' in that case. */ if ((((unsigned HOST_WIDE_INT) tree_low_cst (len, 1)) & 3) == 0) return; } else if (TREE_CODE (len) == SSA_NAME) { gimple def_stmt = SSA_NAME_DEF_STMT (len); if (!is_gimple_assign (def_stmt) || gimple_assign_rhs_code (def_stmt) != PLUS_EXPR || gimple_assign_rhs1 (def_stmt) != last.len || !integer_onep (gimple_assign_rhs2 (def_stmt))) return; } else return; gimple_call_set_arg (last.stmt, 2, last.len); update_stmt (last.stmt); } /* Handle a strlen call. If strlen of the argument is known, replace the strlen call with the known value, otherwise remember that strlen of the argument is stored in the lhs SSA_NAME. */ static void handle_builtin_strlen (gimple_stmt_iterator *gsi) { int idx; tree src; gimple stmt = gsi_stmt (*gsi); tree lhs = gimple_call_lhs (stmt); if (lhs == NULL_TREE) return; src = gimple_call_arg (stmt, 0); idx = get_stridx (src); if (idx) { strinfo si = NULL; tree rhs; if (idx < 0) rhs = build_int_cst (TREE_TYPE (lhs), ~idx); else { rhs = NULL_TREE; si = get_strinfo (idx); if (si != NULL) rhs = get_string_length (si); } if (rhs != NULL_TREE) { if (dump_file && (dump_flags & TDF_DETAILS) != 0) { fprintf (dump_file, "Optimizing: "); print_gimple_stmt (dump_file, stmt, 0, TDF_SLIM); } rhs = unshare_expr (rhs); if (!useless_type_conversion_p (TREE_TYPE (lhs), TREE_TYPE (rhs))) rhs = fold_convert_loc (gimple_location (stmt), TREE_TYPE (lhs), rhs); if (!update_call_from_tree (gsi, rhs)) gimplify_and_update_call_from_tree (gsi, rhs); stmt = gsi_stmt (*gsi); update_stmt (stmt); if (dump_file && (dump_flags & TDF_DETAILS) != 0) { fprintf (dump_file, "into: "); print_gimple_stmt (dump_file, stmt, 0, TDF_SLIM); } if (si != NULL && TREE_CODE (si->length) != SSA_NAME && TREE_CODE (si->length) != INTEGER_CST && !SSA_NAME_OCCURS_IN_ABNORMAL_PHI (lhs)) { si = unshare_strinfo (si); si->length = lhs; } return; } } if (SSA_NAME_OCCURS_IN_ABNORMAL_PHI (lhs)) return; if (idx == 0) idx = new_stridx (src); else if (get_strinfo (idx) != NULL) return; if (idx) { strinfo si = new_strinfo (src, idx, lhs); set_strinfo (idx, si); find_equal_ptrs (src, idx); } } /* Handle a strchr call. If strlen of the first argument is known, replace the strchr (x, 0) call with the endptr or x + strlen, otherwise remember that lhs of the call is endptr and strlen of the argument is endptr - x. */ static void handle_builtin_strchr (gimple_stmt_iterator *gsi) { int idx; tree src; gimple stmt = gsi_stmt (*gsi); tree lhs = gimple_call_lhs (stmt); if (lhs == NULL_TREE) return; if (!integer_zerop (gimple_call_arg (stmt, 1))) return; src = gimple_call_arg (stmt, 0); idx = get_stridx (src); if (idx) { strinfo si = NULL; tree rhs; if (idx < 0) rhs = build_int_cst (size_type_node, ~idx); else { rhs = NULL_TREE; si = get_strinfo (idx); if (si != NULL) rhs = get_string_length (si); } if (rhs != NULL_TREE) { location_t loc = gimple_location (stmt); if (dump_file && (dump_flags & TDF_DETAILS) != 0) { fprintf (dump_file, "Optimizing: "); print_gimple_stmt (dump_file, stmt, 0, TDF_SLIM); } if (si != NULL && si->endptr != NULL_TREE) { rhs = unshare_expr (si->endptr); if (!useless_type_conversion_p (TREE_TYPE (lhs), TREE_TYPE (rhs))) rhs = fold_convert_loc (loc, TREE_TYPE (lhs), rhs); } else { rhs = fold_convert_loc (loc, sizetype, unshare_expr (rhs)); rhs = fold_build2_loc (loc, POINTER_PLUS_EXPR, TREE_TYPE (src), src, rhs); if (!useless_type_conversion_p (TREE_TYPE (lhs), TREE_TYPE (rhs))) rhs = fold_convert_loc (loc, TREE_TYPE (lhs), rhs); } if (!update_call_from_tree (gsi, rhs)) gimplify_and_update_call_from_tree (gsi, rhs); stmt = gsi_stmt (*gsi); update_stmt (stmt); if (dump_file && (dump_flags & TDF_DETAILS) != 0) { fprintf (dump_file, "into: "); print_gimple_stmt (dump_file, stmt, 0, TDF_SLIM); } if (si != NULL && si->endptr == NULL_TREE && !SSA_NAME_OCCURS_IN_ABNORMAL_PHI (lhs)) { si = unshare_strinfo (si); si->endptr = lhs; } zero_length_string (lhs, si); return; } } if (SSA_NAME_OCCURS_IN_ABNORMAL_PHI (lhs)) return; if (TREE_CODE (src) != SSA_NAME || !SSA_NAME_OCCURS_IN_ABNORMAL_PHI (src)) { if (idx == 0) idx = new_stridx (src); else if (get_strinfo (idx) != NULL) { zero_length_string (lhs, NULL); return; } if (idx) { location_t loc = gimple_location (stmt); tree lhsu = fold_convert_loc (loc, size_type_node, lhs); tree srcu = fold_convert_loc (loc, size_type_node, src); tree length = fold_build2_loc (loc, MINUS_EXPR, size_type_node, lhsu, srcu); strinfo si = new_strinfo (src, idx, length); si->endptr = lhs; set_strinfo (idx, si); find_equal_ptrs (src, idx); zero_length_string (lhs, si); } } else zero_length_string (lhs, NULL); } /* Handle a strcpy-like ({st{r,p}cpy,__st{r,p}cpy_chk}) call. If strlen of the second argument is known, strlen of the first argument is the same after this call. Furthermore, attempt to convert it to memcpy. */ static void handle_builtin_strcpy (enum built_in_function bcode, gimple_stmt_iterator *gsi) { int idx, didx; tree src, dst, srclen, len, lhs, args, type, fn, oldlen; bool success; gimple stmt = gsi_stmt (*gsi); strinfo si, dsi, olddsi, zsi; location_t loc; src = gimple_call_arg (stmt, 1); dst = gimple_call_arg (stmt, 0); lhs = gimple_call_lhs (stmt); idx = get_stridx (src); si = NULL; if (idx > 0) si = get_strinfo (idx); didx = get_stridx (dst); olddsi = NULL; oldlen = NULL_TREE; if (didx > 0) olddsi = get_strinfo (didx); else if (didx < 0) return; if (olddsi != NULL) adjust_last_stmt (olddsi, stmt, false); srclen = NULL_TREE; if (si != NULL) srclen = get_string_length (si); else if (idx < 0) srclen = build_int_cst (size_type_node, ~idx); loc = gimple_location (stmt); if (srclen == NULL_TREE) switch (bcode) { case BUILT_IN_STRCPY: case BUILT_IN_STRCPY_CHK: if (lhs != NULL_TREE || !builtin_decl_implicit_p (BUILT_IN_STPCPY)) return; break; case BUILT_IN_STPCPY: case BUILT_IN_STPCPY_CHK: if (lhs == NULL_TREE) return; else { tree lhsuint = fold_convert_loc (loc, size_type_node, lhs); srclen = fold_convert_loc (loc, size_type_node, dst); srclen = fold_build2_loc (loc, MINUS_EXPR, size_type_node, lhsuint, srclen); } break; default: gcc_unreachable (); } if (didx == 0) { didx = new_stridx (dst); if (didx == 0) return; } if (olddsi != NULL) { oldlen = olddsi->length; dsi = unshare_strinfo (olddsi); dsi->length = srclen; /* Break the chain, so adjust_related_strinfo on later pointers in the chain won't adjust this one anymore. */ dsi->next = 0; dsi->stmt = NULL; dsi->endptr = NULL_TREE; } else { dsi = new_strinfo (dst, didx, srclen); set_strinfo (didx, dsi); find_equal_ptrs (dst, didx); } dsi->writable = true; dsi->dont_invalidate = true; if (dsi->length == NULL_TREE) { strinfo chainsi; /* If string length of src is unknown, use delayed length computation. If string lenth of dst will be needed, it can be computed by transforming this strcpy call into stpcpy and subtracting dst from the return value. */ /* Look for earlier strings whose length could be determined if this strcpy is turned into an stpcpy. */ if (dsi->prev != 0 && (chainsi = verify_related_strinfos (dsi)) != NULL) { for (; chainsi && chainsi != dsi; chainsi = get_strinfo (chainsi->next)) { /* When setting a stmt for delayed length computation prevent all strinfos through dsi from being invalidated. */ chainsi = unshare_strinfo (chainsi); chainsi->stmt = stmt; chainsi->length = NULL_TREE; chainsi->endptr = NULL_TREE; chainsi->dont_invalidate = true; } } dsi->stmt = stmt; return; } if (olddsi != NULL) { tree adj = NULL_TREE; if (oldlen == NULL_TREE) ; else if (integer_zerop (oldlen)) adj = srclen; else if (TREE_CODE (oldlen) == INTEGER_CST || TREE_CODE (srclen) == INTEGER_CST) adj = fold_build2_loc (loc, MINUS_EXPR, TREE_TYPE (srclen), srclen, fold_convert_loc (loc, TREE_TYPE (srclen), oldlen)); if (adj != NULL_TREE) adjust_related_strinfos (loc, dsi, adj); else dsi->prev = 0; } /* strcpy src may not overlap dst, so src doesn't need to be invalidated either. */ if (si != NULL) si->dont_invalidate = true; fn = NULL_TREE; zsi = NULL; switch (bcode) { case BUILT_IN_STRCPY: fn = builtin_decl_implicit (BUILT_IN_MEMCPY); if (lhs) VEC_replace (int, ssa_ver_to_stridx, SSA_NAME_VERSION (lhs), didx); break; case BUILT_IN_STRCPY_CHK: fn = builtin_decl_explicit (BUILT_IN_MEMCPY_CHK); if (lhs) VEC_replace (int, ssa_ver_to_stridx, SSA_NAME_VERSION (lhs), didx); break; case BUILT_IN_STPCPY: /* This would need adjustment of the lhs (subtract one), or detection that the trailing '\0' doesn't need to be written, if it will be immediately overwritten. fn = builtin_decl_explicit (BUILT_IN_MEMPCPY); */ if (lhs) { dsi->endptr = lhs; zsi = zero_length_string (lhs, dsi); } break; case BUILT_IN_STPCPY_CHK: /* This would need adjustment of the lhs (subtract one), or detection that the trailing '\0' doesn't need to be written, if it will be immediately overwritten. fn = builtin_decl_explicit (BUILT_IN_MEMPCPY_CHK); */ if (lhs) { dsi->endptr = lhs; zsi = zero_length_string (lhs, dsi); } break; default: gcc_unreachable (); } if (zsi != NULL) zsi->dont_invalidate = true; if (fn == NULL_TREE) return; args = TYPE_ARG_TYPES (TREE_TYPE (fn)); type = TREE_VALUE (TREE_CHAIN (TREE_CHAIN (args))); len = fold_convert_loc (loc, type, unshare_expr (srclen)); len = fold_build2_loc (loc, PLUS_EXPR, type, len, build_int_cst (type, 1)); len = force_gimple_operand_gsi (gsi, len, true, NULL_TREE, true, GSI_SAME_STMT); if (dump_file && (dump_flags & TDF_DETAILS) != 0) { fprintf (dump_file, "Optimizing: "); print_gimple_stmt (dump_file, stmt, 0, TDF_SLIM); } if (gimple_call_num_args (stmt) == 2) success = update_gimple_call (gsi, fn, 3, dst, src, len); else success = update_gimple_call (gsi, fn, 4, dst, src, len, gimple_call_arg (stmt, 2)); if (success) { stmt = gsi_stmt (*gsi); update_stmt (stmt); if (dump_file && (dump_flags & TDF_DETAILS) != 0) { fprintf (dump_file, "into: "); print_gimple_stmt (dump_file, stmt, 0, TDF_SLIM); } /* Allow adjust_last_stmt to decrease this memcpy's size. */ laststmt.stmt = stmt; laststmt.len = srclen; laststmt.stridx = dsi->idx; } else if (dump_file && (dump_flags & TDF_DETAILS) != 0) fprintf (dump_file, "not possible.\n"); } /* Handle a memcpy-like ({mem{,p}cpy,__mem{,p}cpy_chk}) call. If strlen of the second argument is known and length of the third argument is that plus one, strlen of the first argument is the same after this call. */ static void handle_builtin_memcpy (enum built_in_function bcode, gimple_stmt_iterator *gsi) { int idx, didx; tree src, dst, len, lhs, oldlen, newlen; gimple stmt = gsi_stmt (*gsi); strinfo si, dsi, olddsi; len = gimple_call_arg (stmt, 2); src = gimple_call_arg (stmt, 1); dst = gimple_call_arg (stmt, 0); idx = get_stridx (src); if (idx == 0) return; didx = get_stridx (dst); olddsi = NULL; if (didx > 0) olddsi = get_strinfo (didx); else if (didx < 0) return; if (olddsi != NULL && host_integerp (len, 1) && !integer_zerop (len)) adjust_last_stmt (olddsi, stmt, false); if (idx > 0) { gimple def_stmt; /* Handle memcpy (x, y, l) where l is strlen (y) + 1. */ si = get_strinfo (idx); if (si == NULL || si->length == NULL_TREE) return; if (TREE_CODE (len) != SSA_NAME) return; def_stmt = SSA_NAME_DEF_STMT (len); if (!is_gimple_assign (def_stmt) || gimple_assign_rhs_code (def_stmt) != PLUS_EXPR || gimple_assign_rhs1 (def_stmt) != si->length || !integer_onep (gimple_assign_rhs2 (def_stmt))) return; } else { si = NULL; /* Handle memcpy (x, "abcd", 5) or memcpy (x, "abc\0uvw", 7). */ if (!host_integerp (len, 1) || (unsigned HOST_WIDE_INT) tree_low_cst (len, 1) <= (unsigned HOST_WIDE_INT) ~idx) return; } if (olddsi != NULL && TREE_CODE (len) == SSA_NAME) adjust_last_stmt (olddsi, stmt, false); if (didx == 0) { didx = new_stridx (dst); if (didx == 0) return; } if (si != NULL) newlen = si->length; else newlen = build_int_cst (size_type_node, ~idx); oldlen = NULL_TREE; if (olddsi != NULL) { dsi = unshare_strinfo (olddsi); oldlen = olddsi->length; dsi->length = newlen; /* Break the chain, so adjust_related_strinfo on later pointers in the chain won't adjust this one anymore. */ dsi->next = 0; dsi->stmt = NULL; dsi->endptr = NULL_TREE; } else { dsi = new_strinfo (dst, didx, newlen); set_strinfo (didx, dsi); find_equal_ptrs (dst, didx); } dsi->writable = true; dsi->dont_invalidate = true; if (olddsi != NULL) { tree adj = NULL_TREE; location_t loc = gimple_location (stmt); if (oldlen == NULL_TREE) ; else if (integer_zerop (oldlen)) adj = dsi->length; else if (TREE_CODE (oldlen) == INTEGER_CST || TREE_CODE (dsi->length) == INTEGER_CST) adj = fold_build2_loc (loc, MINUS_EXPR, TREE_TYPE (dsi->length), dsi->length, fold_convert_loc (loc, TREE_TYPE (dsi->length), oldlen)); if (adj != NULL_TREE) adjust_related_strinfos (loc, dsi, adj); else dsi->prev = 0; } /* memcpy src may not overlap dst, so src doesn't need to be invalidated either. */ if (si != NULL) si->dont_invalidate = true; lhs = gimple_call_lhs (stmt); switch (bcode) { case BUILT_IN_MEMCPY: case BUILT_IN_MEMCPY_CHK: /* Allow adjust_last_stmt to decrease this memcpy's size. */ laststmt.stmt = stmt; laststmt.len = dsi->length; laststmt.stridx = dsi->idx; if (lhs) VEC_replace (int, ssa_ver_to_stridx, SSA_NAME_VERSION (lhs), didx); break; case BUILT_IN_MEMPCPY: case BUILT_IN_MEMPCPY_CHK: break; default: gcc_unreachable (); } } /* Handle a strcat-like ({strcat,__strcat_chk}) call. If strlen of the second argument is known, strlen of the first argument is increased by the length of the second argument. Furthermore, attempt to convert it to memcpy/strcpy if the length of the first argument is known. */ static void handle_builtin_strcat (enum built_in_function bcode, gimple_stmt_iterator *gsi) { int idx, didx; tree src, dst, srclen, dstlen, len, lhs, args, type, fn, objsz, endptr; bool success; gimple stmt = gsi_stmt (*gsi); strinfo si, dsi; location_t loc; src = gimple_call_arg (stmt, 1); dst = gimple_call_arg (stmt, 0); lhs = gimple_call_lhs (stmt); didx = get_stridx (dst); if (didx < 0) return; dsi = NULL; if (didx > 0) dsi = get_strinfo (didx); if (dsi == NULL || get_string_length (dsi) == NULL_TREE) { /* strcat (p, q) can be transformed into tmp = p + strlen (p); endptr = strpcpy (tmp, q); with length endptr - p if we need to compute the length later on. Don't do this transformation if we don't need it. */ if (builtin_decl_implicit_p (BUILT_IN_STPCPY) && lhs == NULL_TREE) { if (didx == 0) { didx = new_stridx (dst); if (didx == 0) return; } if (dsi == NULL) { dsi = new_strinfo (dst, didx, NULL_TREE); set_strinfo (didx, dsi); find_equal_ptrs (dst, didx); } else { dsi = unshare_strinfo (dsi); dsi->length = NULL_TREE; dsi->next = 0; dsi->endptr = NULL_TREE; } dsi->writable = true; dsi->stmt = stmt; dsi->dont_invalidate = true; } return; } srclen = NULL_TREE; si = NULL; idx = get_stridx (src); if (idx < 0) srclen = build_int_cst (size_type_node, ~idx); else if (idx > 0) { si = get_strinfo (idx); if (si != NULL) srclen = get_string_length (si); } loc = gimple_location (stmt); dstlen = dsi->length; endptr = dsi->endptr; dsi = unshare_strinfo (dsi); dsi->endptr = NULL_TREE; dsi->stmt = NULL; dsi->writable = true; if (srclen != NULL_TREE) { dsi->length = fold_build2_loc (loc, PLUS_EXPR, TREE_TYPE (dsi->length), dsi->length, srclen); adjust_related_strinfos (loc, dsi, srclen); dsi->dont_invalidate = true; } else { dsi->length = NULL; if (lhs == NULL_TREE && builtin_decl_implicit_p (BUILT_IN_STPCPY)) dsi->dont_invalidate = true; } if (si != NULL) /* strcat src may not overlap dst, so src doesn't need to be invalidated either. */ si->dont_invalidate = true; /* For now. Could remove the lhs from the call and add lhs = dst; afterwards. */ if (lhs) return; fn = NULL_TREE; objsz = NULL_TREE; switch (bcode) { case BUILT_IN_STRCAT: if (srclen != NULL_TREE) fn = builtin_decl_implicit (BUILT_IN_MEMCPY); else fn = builtin_decl_implicit (BUILT_IN_STRCPY); break; case BUILT_IN_STRCAT_CHK: if (srclen != NULL_TREE) fn = builtin_decl_explicit (BUILT_IN_MEMCPY_CHK); else fn = builtin_decl_explicit (BUILT_IN_STRCPY_CHK); objsz = gimple_call_arg (stmt, 2); break; default: gcc_unreachable (); } if (fn == NULL_TREE) return; len = NULL_TREE; if (srclen != NULL_TREE) { args = TYPE_ARG_TYPES (TREE_TYPE (fn)); type = TREE_VALUE (TREE_CHAIN (TREE_CHAIN (args))); len = fold_convert_loc (loc, type, unshare_expr (srclen)); len = fold_build2_loc (loc, PLUS_EXPR, type, len, build_int_cst (type, 1)); len = force_gimple_operand_gsi (gsi, len, true, NULL_TREE, true, GSI_SAME_STMT); } if (endptr) dst = fold_convert_loc (loc, TREE_TYPE (dst), unshare_expr (endptr)); else dst = fold_build2_loc (loc, POINTER_PLUS_EXPR, TREE_TYPE (dst), unshare_expr (dst), fold_convert_loc (loc, sizetype, unshare_expr (dstlen))); dst = force_gimple_operand_gsi (gsi, dst, true, NULL_TREE, true, GSI_SAME_STMT); if (dump_file && (dump_flags & TDF_DETAILS) != 0) { fprintf (dump_file, "Optimizing: "); print_gimple_stmt (dump_file, stmt, 0, TDF_SLIM); } if (srclen != NULL_TREE) success = update_gimple_call (gsi, fn, 3 + (objsz != NULL_TREE), dst, src, len, objsz); else success = update_gimple_call (gsi, fn, 2 + (objsz != NULL_TREE), dst, src, objsz); if (success) { stmt = gsi_stmt (*gsi); update_stmt (stmt); if (dump_file && (dump_flags & TDF_DETAILS) != 0) { fprintf (dump_file, "into: "); print_gimple_stmt (dump_file, stmt, 0, TDF_SLIM); } /* If srclen == NULL, note that current string length can be computed by transforming this strcpy into stpcpy. */ if (srclen == NULL_TREE && dsi->dont_invalidate) dsi->stmt = stmt; adjust_last_stmt (dsi, stmt, true); if (srclen != NULL_TREE) { laststmt.stmt = stmt; laststmt.len = srclen; laststmt.stridx = dsi->idx; } } else if (dump_file && (dump_flags & TDF_DETAILS) != 0) fprintf (dump_file, "not possible.\n"); } /* Handle a POINTER_PLUS_EXPR statement. For p = "abcd" + 2; compute associated length, or if p = q + off is pointing to a '\0' character of a string, call zero_length_string on it. */ static void handle_pointer_plus (gimple_stmt_iterator *gsi) { gimple stmt = gsi_stmt (*gsi); tree lhs = gimple_assign_lhs (stmt), off; int idx = get_stridx (gimple_assign_rhs1 (stmt)); strinfo si, zsi; if (idx == 0) return; if (idx < 0) { tree off = gimple_assign_rhs2 (stmt); if (host_integerp (off, 1) && (unsigned HOST_WIDE_INT) tree_low_cst (off, 1) <= (unsigned HOST_WIDE_INT) ~idx) VEC_replace (int, ssa_ver_to_stridx, SSA_NAME_VERSION (lhs), ~(~idx - (int) tree_low_cst (off, 1))); return; } si = get_strinfo (idx); if (si == NULL || si->length == NULL_TREE) return; off = gimple_assign_rhs2 (stmt); zsi = NULL; if (operand_equal_p (si->length, off, 0)) zsi = zero_length_string (lhs, si); else if (TREE_CODE (off) == SSA_NAME) { gimple def_stmt = SSA_NAME_DEF_STMT (off); if (gimple_assign_single_p (def_stmt) && operand_equal_p (si->length, gimple_assign_rhs1 (def_stmt), 0)) zsi = zero_length_string (lhs, si); } if (zsi != NULL && si->endptr != NULL_TREE && si->endptr != lhs && TREE_CODE (si->endptr) == SSA_NAME) { enum tree_code rhs_code = useless_type_conversion_p (TREE_TYPE (lhs), TREE_TYPE (si->endptr)) ? SSA_NAME : NOP_EXPR; gimple_assign_set_rhs_with_ops (gsi, rhs_code, si->endptr, NULL_TREE); gcc_assert (gsi_stmt (*gsi) == stmt); update_stmt (stmt); } } /* Handle a single character store. */ static bool handle_char_store (gimple_stmt_iterator *gsi) { int idx = -1; strinfo si = NULL; gimple stmt = gsi_stmt (*gsi); tree ssaname = NULL_TREE, lhs = gimple_assign_lhs (stmt); if (TREE_CODE (lhs) == MEM_REF && TREE_CODE (TREE_OPERAND (lhs, 0)) == SSA_NAME) { if (integer_zerop (TREE_OPERAND (lhs, 1))) { ssaname = TREE_OPERAND (lhs, 0); idx = get_stridx (ssaname); } } else idx = get_addr_stridx (lhs); if (idx > 0) { si = get_strinfo (idx); if (si != NULL && si->length != NULL_TREE && integer_zerop (si->length)) { if (initializer_zerop (gimple_assign_rhs1 (stmt))) { /* When storing '\0', the store can be removed if we know it has been stored in the current function. */ if (!stmt_could_throw_p (stmt) && si->writable) { unlink_stmt_vdef (stmt); release_defs (stmt); gsi_remove (gsi, true); return false; } else { si->writable = true; si->dont_invalidate = true; } } else /* Otherwise this statement overwrites the '\0' with something, if the previous stmt was a memcpy, its length may be decreased. */ adjust_last_stmt (si, stmt, false); } else if (si != NULL) { si = unshare_strinfo (si); si->length = build_int_cst (size_type_node, 0); si->endptr = NULL; si->prev = 0; si->next = 0; si->stmt = NULL; si->first = 0; si->writable = true; if (ssaname && !SSA_NAME_OCCURS_IN_ABNORMAL_PHI (ssaname)) si->endptr = ssaname; si->dont_invalidate = true; } } else if (idx == 0 && initializer_zerop (gimple_assign_rhs1 (stmt))) { if (ssaname) { si = zero_length_string (ssaname, NULL); if (si != NULL) si->dont_invalidate = true; } else { int idx = new_addr_stridx (lhs); if (idx != 0) { si = new_strinfo (build_fold_addr_expr (lhs), idx, build_int_cst (size_type_node, 0)); set_strinfo (idx, si); si->dont_invalidate = true; } } if (si != NULL) si->writable = true; } if (si != NULL && initializer_zerop (gimple_assign_rhs1 (stmt))) { /* Allow adjust_last_stmt to remove it if the stored '\0' is immediately overwritten. */ laststmt.stmt = stmt; laststmt.len = build_int_cst (size_type_node, 1); laststmt.stridx = si->idx; } return true; } /* Attempt to optimize a single statement at *GSI using string length knowledge. */ static bool strlen_optimize_stmt (gimple_stmt_iterator *gsi) { gimple stmt = gsi_stmt (*gsi); if (is_gimple_call (stmt)) { tree callee = gimple_call_fndecl (stmt); if (callee && DECL_BUILT_IN_CLASS (callee) == BUILT_IN_NORMAL) switch (DECL_FUNCTION_CODE (callee)) { case BUILT_IN_STRLEN: handle_builtin_strlen (gsi); break; case BUILT_IN_STRCHR: handle_builtin_strchr (gsi); break; case BUILT_IN_STRCPY: case BUILT_IN_STRCPY_CHK: case BUILT_IN_STPCPY: case BUILT_IN_STPCPY_CHK: handle_builtin_strcpy (DECL_FUNCTION_CODE (callee), gsi); break; case BUILT_IN_MEMCPY: case BUILT_IN_MEMCPY_CHK: case BUILT_IN_MEMPCPY: case BUILT_IN_MEMPCPY_CHK: handle_builtin_memcpy (DECL_FUNCTION_CODE (callee), gsi); break; case BUILT_IN_STRCAT: case BUILT_IN_STRCAT_CHK: handle_builtin_strcat (DECL_FUNCTION_CODE (callee), gsi); break; default: break; } } else if (is_gimple_assign (stmt)) { tree lhs = gimple_assign_lhs (stmt); if (TREE_CODE (lhs) == SSA_NAME && POINTER_TYPE_P (TREE_TYPE (lhs))) { if (gimple_assign_single_p (stmt) || (gimple_assign_cast_p (stmt) && POINTER_TYPE_P (TREE_TYPE (gimple_assign_rhs1 (stmt))))) { int idx = get_stridx (gimple_assign_rhs1 (stmt)); VEC_replace (int, ssa_ver_to_stridx, SSA_NAME_VERSION (lhs), idx); } else if (gimple_assign_rhs_code (stmt) == POINTER_PLUS_EXPR) handle_pointer_plus (gsi); } else if (TREE_CODE (lhs) != SSA_NAME && !TREE_SIDE_EFFECTS (lhs)) { tree type = TREE_TYPE (lhs); if (TREE_CODE (type) == ARRAY_TYPE) type = TREE_TYPE (type); if (TREE_CODE (type) == INTEGER_TYPE && TYPE_MODE (type) == TYPE_MODE (char_type_node) && TYPE_PRECISION (type) == TYPE_PRECISION (char_type_node)) { if (! handle_char_store (gsi)) return false; } } } if (gimple_vdef (stmt)) maybe_invalidate (stmt); return true; } /* Recursively call maybe_invalidate on stmts that might be executed in between dombb and current bb and that contain a vdef. Stop when *count stmts are inspected, or if the whole strinfo vector has been invalidated. */ static void do_invalidate (basic_block dombb, gimple phi, bitmap visited, int *count) { unsigned int i, n = gimple_phi_num_args (phi); for (i = 0; i < n; i++) { tree vuse = gimple_phi_arg_def (phi, i); gimple stmt = SSA_NAME_DEF_STMT (vuse); basic_block bb = gimple_bb (stmt); if (bb == NULL || bb == dombb || !bitmap_set_bit (visited, bb->index) || !dominated_by_p (CDI_DOMINATORS, bb, dombb)) continue; while (1) { if (gimple_code (stmt) == GIMPLE_PHI) { do_invalidate (dombb, stmt, visited, count); if (*count == 0) return; break; } if (--*count == 0) return; if (!maybe_invalidate (stmt)) { *count = 0; return; } vuse = gimple_vuse (stmt); stmt = SSA_NAME_DEF_STMT (vuse); if (gimple_bb (stmt) != bb) { bb = gimple_bb (stmt); if (bb == NULL || bb == dombb || !bitmap_set_bit (visited, bb->index) || !dominated_by_p (CDI_DOMINATORS, bb, dombb)) break; } } } } /* Callback for walk_dominator_tree. Attempt to optimize various string ops by remembering string lenths pointed by pointer SSA_NAMEs. */ static void strlen_enter_block (struct dom_walk_data *walk_data ATTRIBUTE_UNUSED, basic_block bb) { gimple_stmt_iterator gsi; basic_block dombb = get_immediate_dominator (CDI_DOMINATORS, bb); if (dombb == NULL) stridx_to_strinfo = NULL; else { stridx_to_strinfo = (VEC(strinfo, heap) *) dombb->aux; if (stridx_to_strinfo) { for (gsi = gsi_start_phis (bb); !gsi_end_p (gsi); gsi_next (&gsi)) { gimple phi = gsi_stmt (gsi); if (!is_gimple_reg (gimple_phi_result (phi))) { bitmap visited = BITMAP_ALLOC (NULL); int count_vdef = 100; do_invalidate (dombb, phi, visited, &count_vdef); BITMAP_FREE (visited); break; } } } } /* If all PHI arguments have the same string index, the PHI result has it as well. */ for (gsi = gsi_start_phis (bb); !gsi_end_p (gsi); gsi_next (&gsi)) { gimple phi = gsi_stmt (gsi); tree result = gimple_phi_result (phi); if (is_gimple_reg (result) && POINTER_TYPE_P (TREE_TYPE (result))) { int idx = get_stridx (gimple_phi_arg_def (phi, 0)); if (idx != 0) { unsigned int i, n = gimple_phi_num_args (phi); for (i = 1; i < n; i++) if (idx != get_stridx (gimple_phi_arg_def (phi, i))) break; if (i == n) VEC_replace (int, ssa_ver_to_stridx, SSA_NAME_VERSION (result), idx); } } } /* Attempt to optimize individual statements. */ for (gsi = gsi_start_bb (bb); !gsi_end_p (gsi); ) if (strlen_optimize_stmt (&gsi)) gsi_next (&gsi); bb->aux = stridx_to_strinfo; if (VEC_length (strinfo, stridx_to_strinfo) && !strinfo_shared ()) VEC_replace (strinfo, stridx_to_strinfo, 0, (strinfo) bb); } /* Callback for walk_dominator_tree. Free strinfo vector if it is owned by the current bb, clear bb->aux. */ static void strlen_leave_block (struct dom_walk_data *walk_data ATTRIBUTE_UNUSED, basic_block bb) { if (bb->aux) { stridx_to_strinfo = (VEC(strinfo, heap) *) bb->aux; if (VEC_length (strinfo, stridx_to_strinfo) && VEC_index (strinfo, stridx_to_strinfo, 0) == (strinfo) bb) { unsigned int i; strinfo si; for (i = 1; VEC_iterate (strinfo, stridx_to_strinfo, i, si); ++i) free_strinfo (si); VEC_free (strinfo, heap, stridx_to_strinfo); } bb->aux = NULL; } } /* Main entry point. */ static unsigned int tree_ssa_strlen (void) { struct dom_walk_data walk_data; VEC_safe_grow_cleared (int, heap, ssa_ver_to_stridx, num_ssa_names); max_stridx = 1; strinfo_pool = create_alloc_pool ("strinfo_struct pool", sizeof (struct strinfo_struct), 64); calculate_dominance_info (CDI_DOMINATORS); /* String length optimization is implemented as a walk of the dominator tree and a forward walk of statements within each block. */ walk_data.dom_direction = CDI_DOMINATORS; walk_data.initialize_block_local_data = NULL; walk_data.before_dom_children = strlen_enter_block; walk_data.after_dom_children = strlen_leave_block; walk_data.block_local_data_size = 0; walk_data.global_data = NULL; /* Initialize the dominator walker. */ init_walk_dominator_tree (&walk_data); /* Recursively walk the dominator tree. */ walk_dominator_tree (&walk_data, ENTRY_BLOCK_PTR); /* Finalize the dominator walker. */ fini_walk_dominator_tree (&walk_data); VEC_free (int, heap, ssa_ver_to_stridx); free_alloc_pool (strinfo_pool); if (decl_to_stridxlist_htab) { obstack_free (&stridx_obstack, NULL); htab_delete (decl_to_stridxlist_htab); decl_to_stridxlist_htab = NULL; } laststmt.stmt = NULL; laststmt.len = NULL_TREE; laststmt.stridx = 0; return 0; } static bool gate_strlen (void) { return flag_optimize_strlen != 0; } struct gimple_opt_pass pass_strlen = { { GIMPLE_PASS, "strlen", /* name */ gate_strlen, /* gate */ tree_ssa_strlen, /* execute */ NULL, /* sub */ NULL, /* next */ 0, /* static_pass_number */ TV_TREE_STRLEN, /* tv_id */ PROP_cfg | PROP_ssa, /* properties_required */ 0, /* properties_provided */ 0, /* properties_destroyed */ 0, /* todo_flags_start */ TODO_ggc_collect | TODO_verify_ssa /* todo_flags_finish */ } };
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