| /* String length optimization |
| Copyright (C) 2011-2017 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 "backend.h" |
| #include "rtl.h" |
| #include "tree.h" |
| #include "gimple.h" |
| #include "alloc-pool.h" |
| #include "tree-pass.h" |
| #include "ssa.h" |
| #include "cgraph.h" |
| #include "gimple-pretty-print.h" |
| #include "fold-const.h" |
| #include "stor-layout.h" |
| #include "gimple-fold.h" |
| #include "tree-eh.h" |
| #include "gimplify.h" |
| #include "gimple-iterator.h" |
| #include "gimplify-me.h" |
| #include "expr.h" |
| #include "tree-dfa.h" |
| #include "domwalk.h" |
| #include "tree-ssa-alias.h" |
| #include "tree-ssa-propagate.h" |
| #include "params.h" |
| #include "ipa-chkp.h" |
| #include "tree-hash-traits.h" |
| #include "builtins.h" |
| #include "target.h" |
| #include "diagnostic-core.h" |
| #include "diagnostic.h" |
| #include "intl.h" |
| #include "attribs.h" |
| #include "calls.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> ssa_ver_to_stridx; |
| |
| /* Number of currently active string indexes plus one. */ |
| static int max_stridx; |
| |
| /* String information record. */ |
| struct strinfo |
| { |
| /* Number of leading characters that are known to be nonzero. This is |
| also the length of the string if FULL_STRING_P. |
| |
| The values in a list of related string pointers must be consistent; |
| that is, if strinfo B comes X bytes after strinfo A, it must be |
| the case that A->nonzero_chars == X + B->nonzero_chars. */ |
| tree nonzero_chars; |
| /* Any of the corresponding pointers for querying alias oracle. */ |
| tree ptr; |
| /* This is used for two things: |
| |
| - To record the statement that should be used for delayed length |
| computations. We maintain the invariant that all related strinfos |
| have delayed lengths or none do. |
| |
| - To record the malloc or calloc call that produced this result. */ |
| 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; |
| /* True if the string is known to be nul-terminated after NONZERO_CHARS |
| characters. False is useful when detecting strings that are built |
| up via successive memcpys. */ |
| bool full_string_p; |
| }; |
| |
| /* Pool for allocating strinfo_struct entries. */ |
| static object_allocator<strinfo> strinfo_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 *, va_heap, vl_embed> *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 hash_map<tree_decl_hash, stridxlist> *decl_to_stridxlist_htab; |
| |
| /* Hash table mapping strlen calls to stridx instances describing |
| the calls' arguments. Non-null only when warn_stringop_truncation |
| is non-zero. */ |
| typedef std::pair<int, location_t> stridx_strlenloc; |
| static hash_map<tree, stridx_strlenloc> *strlen_to_stridx; |
| |
| /* 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; |
| |
| static int get_stridx_plus_constant (strinfo *, unsigned HOST_WIDE_INT, tree); |
| |
| /* Return: |
| |
| - 1 if SI is known to start with more than OFF nonzero characters. |
| |
| - 0 if SI is known to start with OFF nonzero characters, |
| but is not known to start with more. |
| |
| - -1 if SI might not start with OFF nonzero characters. */ |
| |
| static inline int |
| compare_nonzero_chars (strinfo *si, unsigned HOST_WIDE_INT off) |
| { |
| if (si->nonzero_chars |
| && TREE_CODE (si->nonzero_chars) == INTEGER_CST) |
| return compare_tree_int (si->nonzero_chars, off); |
| else |
| return -1; |
| } |
| |
| /* Return true if SI is known to be a zero-length string. */ |
| |
| static inline bool |
| zero_length_string_p (strinfo *si) |
| { |
| return si->full_string_p && integer_zerop (si->nonzero_chars); |
| } |
| |
| /* Return strinfo vector entry IDX. */ |
| |
| static inline strinfo * |
| get_strinfo (int idx) |
| { |
| if (vec_safe_length (stridx_to_strinfo) <= (unsigned int) idx) |
| return NULL; |
| return (*stridx_to_strinfo)[idx]; |
| } |
| |
| /* Get the next strinfo in the chain after SI, or null if none. */ |
| |
| static inline strinfo * |
| get_next_strinfo (strinfo *si) |
| { |
| if (si->next == 0) |
| return NULL; |
| strinfo *nextsi = get_strinfo (si->next); |
| if (nextsi == NULL || nextsi->first != si->first || nextsi->prev != si->idx) |
| return NULL; |
| return nextsi; |
| } |
| |
| /* Helper function for get_stridx. Return the strinfo index of the address |
| of EXP, which is available in PTR if nonnull. If OFFSET_OUT, it is |
| OK to return the index for some X <= &EXP and store &EXP - X in |
| *OFFSET_OUT. */ |
| |
| static int |
| get_addr_stridx (tree exp, tree ptr, unsigned HOST_WIDE_INT *offset_out) |
| { |
| HOST_WIDE_INT off; |
| struct stridxlist *list, *last = NULL; |
| tree base; |
| |
| if (!decl_to_stridxlist_htab) |
| return 0; |
| |
| base = get_addr_base_and_unit_offset (exp, &off); |
| if (base == NULL || !DECL_P (base)) |
| return 0; |
| |
| list = decl_to_stridxlist_htab->get (base); |
| if (list == NULL) |
| return 0; |
| |
| do |
| { |
| if (list->offset == off) |
| { |
| if (offset_out) |
| *offset_out = 0; |
| return list->idx; |
| } |
| if (list->offset > off) |
| return 0; |
| last = list; |
| list = list->next; |
| } |
| while (list); |
| |
| if ((offset_out || ptr) && last && last->idx > 0) |
| { |
| unsigned HOST_WIDE_INT rel_off |
| = (unsigned HOST_WIDE_INT) off - last->offset; |
| strinfo *si = get_strinfo (last->idx); |
| if (si && compare_nonzero_chars (si, rel_off) >= 0) |
| { |
| if (offset_out) |
| { |
| *offset_out = rel_off; |
| return last->idx; |
| } |
| else |
| return get_stridx_plus_constant (si, rel_off, ptr); |
| } |
| } |
| return 0; |
| } |
| |
| /* Return string index for EXP. */ |
| |
| static int |
| get_stridx (tree exp) |
| { |
| tree s, o; |
| |
| if (TREE_CODE (exp) == SSA_NAME) |
| { |
| if (ssa_ver_to_stridx[SSA_NAME_VERSION (exp)]) |
| return ssa_ver_to_stridx[SSA_NAME_VERSION (exp)]; |
| int i; |
| tree e = exp; |
| HOST_WIDE_INT off = 0; |
| for (i = 0; i < 5; i++) |
| { |
| gimple *def_stmt = SSA_NAME_DEF_STMT (e); |
| if (!is_gimple_assign (def_stmt) |
| || gimple_assign_rhs_code (def_stmt) != POINTER_PLUS_EXPR) |
| return 0; |
| tree rhs1 = gimple_assign_rhs1 (def_stmt); |
| tree rhs2 = gimple_assign_rhs2 (def_stmt); |
| if (TREE_CODE (rhs1) != SSA_NAME |
| || !tree_fits_shwi_p (rhs2)) |
| return 0; |
| HOST_WIDE_INT this_off = tree_to_shwi (rhs2); |
| if (this_off < 0) |
| return 0; |
| off = (unsigned HOST_WIDE_INT) off + this_off; |
| if (off < 0) |
| return 0; |
| if (ssa_ver_to_stridx[SSA_NAME_VERSION (rhs1)]) |
| { |
| strinfo *si |
| = get_strinfo (ssa_ver_to_stridx[SSA_NAME_VERSION (rhs1)]); |
| if (si && compare_nonzero_chars (si, off) >= 0) |
| return get_stridx_plus_constant (si, off, exp); |
| } |
| e = rhs1; |
| } |
| return 0; |
| } |
| |
| if (TREE_CODE (exp) == ADDR_EXPR) |
| { |
| int idx = get_addr_stridx (TREE_OPERAND (exp, 0), exp, NULL); |
| if (idx != 0) |
| return idx; |
| } |
| |
| s = string_constant (exp, &o); |
| if (s != NULL_TREE |
| && (o == NULL_TREE || tree_fits_shwi_p (o)) |
| && TREE_STRING_LENGTH (s) > 0) |
| { |
| HOST_WIDE_INT offset = o ? tree_to_shwi (o) : 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_safe_length (stridx_to_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_safe_copy (stridx_to_strinfo); |
| for (i = 1; vec_safe_iterate (stridx_to_strinfo, i, &si); ++i) |
| if (si != NULL) |
| si->refcount++; |
| (*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) |
| { |
| 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) |
| { |
| decl_to_stridxlist_htab |
| = new hash_map<tree_decl_hash, stridxlist> (64); |
| gcc_obstack_init (&stridx_obstack); |
| } |
| |
| bool existed; |
| stridxlist *list = &decl_to_stridxlist_htab->get_or_insert (base, &existed); |
| if (existed) |
| { |
| int i; |
| stridxlist *before = NULL; |
| for (i = 0; i < 32; i++) |
| { |
| if (list->offset == off) |
| return &list->idx; |
| if (list->offset > off && before == NULL) |
| before = list; |
| if (list->next == NULL) |
| break; |
| list = list->next; |
| } |
| if (i == 32) |
| return NULL; |
| if (before) |
| { |
| list = before; |
| before = XOBNEW (&stridx_obstack, struct stridxlist); |
| *before = *list; |
| list->next = before; |
| list->offset = off; |
| list->idx = 0; |
| return &list->idx; |
| } |
| list->next = XOBNEW (&stridx_obstack, struct stridxlist); |
| list = list->next; |
| } |
| |
| 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++; |
| 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 nonzero_chars, bool full_string_p) |
| { |
| strinfo *si = strinfo_pool.allocate (); |
| si->nonzero_chars = nonzero_chars; |
| 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; |
| si->full_string_p = full_string_p; |
| return si; |
| } |
| |
| /* Decrease strinfo refcount and free it if not referenced anymore. */ |
| |
| static inline void |
| free_strinfo (strinfo *si) |
| { |
| if (si && --si->refcount == 0) |
| strinfo_pool.remove (si); |
| } |
| |
| /* Set strinfo in the vector entry IDX to SI. */ |
| |
| static inline void |
| set_strinfo (int idx, strinfo *si) |
| { |
| if (vec_safe_length (stridx_to_strinfo) && (*stridx_to_strinfo)[0]) |
| unshare_strinfo_vec (); |
| if (vec_safe_length (stridx_to_strinfo) <= (unsigned int) idx) |
| vec_safe_grow_cleared (stridx_to_strinfo, idx + 1); |
| (*stridx_to_strinfo)[idx] = si; |
| } |
| |
| /* Return the 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; |
| } |
| |
| /* Set SI's endptr to ENDPTR and compute its length based on SI->ptr. |
| Use LOC for folding. */ |
| |
| static void |
| set_endptr_and_length (location_t loc, strinfo *si, tree endptr) |
| { |
| si->endptr = endptr; |
| si->stmt = NULL; |
| tree start_as_size = fold_convert_loc (loc, size_type_node, si->ptr); |
| tree end_as_size = fold_convert_loc (loc, size_type_node, endptr); |
| si->nonzero_chars = fold_build2_loc (loc, MINUS_EXPR, size_type_node, |
| end_as_size, start_as_size); |
| si->full_string_p = true; |
| } |
| |
| /* Return string length, or NULL if it can't be computed. */ |
| |
| static tree |
| get_string_length (strinfo *si) |
| { |
| if (si->nonzero_chars) |
| return si->full_string_p ? si->nonzero_chars : NULL; |
| |
| if (si->stmt) |
| { |
| gimple *stmt = si->stmt, *lenstmt; |
| bool with_bounds = gimple_call_with_bounds_p (stmt); |
| tree callee, lhs, 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); |
| /* 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: |
| case BUILT_IN_STRCAT_CHKP: |
| case BUILT_IN_STRCAT_CHK_CHKP: |
| gsi = gsi_for_stmt (stmt); |
| fn = builtin_decl_implicit (BUILT_IN_STRLEN); |
| gcc_assert (lhs == NULL_TREE); |
| tem = unshare_expr (gimple_call_arg (stmt, 0)); |
| if (with_bounds) |
| { |
| lenstmt = gimple_build_call (chkp_maybe_create_clone (fn)->decl, |
| 2, tem, gimple_call_arg (stmt, 1)); |
| gimple_call_set_with_bounds (lenstmt, true); |
| } |
| else |
| lenstmt = gimple_build_call (fn, 1, tem); |
| lhs = make_ssa_name (TREE_TYPE (TREE_TYPE (fn)), lenstmt); |
| gimple_call_set_lhs (lenstmt, lhs); |
| gimple_set_vuse (lenstmt, gimple_vuse (stmt)); |
| gsi_insert_before (&gsi, lenstmt, GSI_SAME_STMT); |
| tem = gimple_call_arg (stmt, 0); |
| if (!ptrofftype_p (TREE_TYPE (lhs))) |
| { |
| lhs = convert_to_ptrofftype (lhs); |
| lhs = force_gimple_operand_gsi (&gsi, lhs, true, NULL_TREE, |
| true, GSI_SAME_STMT); |
| } |
| lenstmt = gimple_build_assign |
| (make_ssa_name (TREE_TYPE (gimple_call_arg (stmt, 0))), |
| POINTER_PLUS_EXPR,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: |
| case BUILT_IN_STRCPY_CHKP: |
| case BUILT_IN_STRCPY_CHK_CHKP: |
| gcc_assert (builtin_decl_implicit_p (BUILT_IN_STPCPY)); |
| if (gimple_call_num_args (stmt) == (with_bounds ? 4 : 2)) |
| fn = builtin_decl_implicit (BUILT_IN_STPCPY); |
| else |
| fn = builtin_decl_explicit (BUILT_IN_STPCPY_CHK); |
| if (with_bounds) |
| fn = chkp_maybe_create_clone (fn)->decl; |
| 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 = make_ssa_name (TREE_TYPE (TREE_TYPE (fn)), 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: |
| case BUILT_IN_STPCPY_CHKP: |
| case BUILT_IN_STPCPY_CHK_CHKP: |
| gcc_assert (lhs != NULL_TREE); |
| loc = gimple_location (stmt); |
| set_endptr_and_length (loc, si, lhs); |
| for (strinfo *chainsi = verify_related_strinfos (si); |
| chainsi != NULL; |
| chainsi = get_next_strinfo (chainsi)) |
| if (chainsi->nonzero_chars == NULL) |
| set_endptr_and_length (loc, chainsi, lhs); |
| break; |
| case BUILT_IN_MALLOC: |
| break; |
| /* BUILT_IN_CALLOC always has si->nonzero_chars set. */ |
| default: |
| gcc_unreachable (); |
| break; |
| } |
| } |
| |
| return si->nonzero_chars; |
| } |
| |
| /* 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_safe_iterate (stridx_to_strinfo, i, &si); ++i) |
| if (si != NULL) |
| { |
| if (!si->dont_invalidate) |
| { |
| ao_ref r; |
| /* Do not use si->nonzero_chars. */ |
| 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 refcount > 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->nonzero_chars, si->full_string_p); |
| 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; |
| } |
| |
| /* Attempt to create a new strinfo for BASESI + OFF, or find existing |
| strinfo if there is any. Return it's idx, or 0 if no strinfo has |
| been created. */ |
| |
| static int |
| get_stridx_plus_constant (strinfo *basesi, unsigned HOST_WIDE_INT off, |
| tree ptr) |
| { |
| if (TREE_CODE (ptr) == SSA_NAME && SSA_NAME_OCCURS_IN_ABNORMAL_PHI (ptr)) |
| return 0; |
| |
| if (compare_nonzero_chars (basesi, off) < 0 |
| || !tree_fits_uhwi_p (basesi->nonzero_chars)) |
| return 0; |
| |
| unsigned HOST_WIDE_INT nonzero_chars |
| = tree_to_uhwi (basesi->nonzero_chars) - off; |
| strinfo *si = basesi, *chainsi; |
| if (si->first || si->prev || si->next) |
| si = verify_related_strinfos (basesi); |
| if (si == NULL |
| || si->nonzero_chars == NULL_TREE |
| || TREE_CODE (si->nonzero_chars) != INTEGER_CST) |
| return 0; |
| |
| if (TREE_CODE (ptr) == SSA_NAME |
| && ssa_ver_to_stridx.length () <= SSA_NAME_VERSION (ptr)) |
| ssa_ver_to_stridx.safe_grow_cleared (num_ssa_names); |
| |
| gcc_checking_assert (compare_tree_int (si->nonzero_chars, off) != -1); |
| for (chainsi = si; chainsi->next; chainsi = si) |
| { |
| si = get_next_strinfo (chainsi); |
| if (si == NULL |
| || si->nonzero_chars == NULL_TREE |
| || TREE_CODE (si->nonzero_chars) != INTEGER_CST) |
| break; |
| int r = compare_tree_int (si->nonzero_chars, nonzero_chars); |
| if (r != 1) |
| { |
| if (r == 0) |
| { |
| if (TREE_CODE (ptr) == SSA_NAME) |
| ssa_ver_to_stridx[SSA_NAME_VERSION (ptr)] = si->idx; |
| else |
| { |
| int *pidx = addr_stridxptr (TREE_OPERAND (ptr, 0)); |
| if (pidx != NULL && *pidx == 0) |
| *pidx = si->idx; |
| } |
| return si->idx; |
| } |
| break; |
| } |
| } |
| |
| int idx = new_stridx (ptr); |
| if (idx == 0) |
| return 0; |
| si = new_strinfo (ptr, idx, build_int_cst (size_type_node, nonzero_chars), |
| basesi->full_string_p); |
| set_strinfo (idx, si); |
| if (chainsi->next) |
| { |
| strinfo *nextsi = unshare_strinfo (get_strinfo (chainsi->next)); |
| si->next = nextsi->idx; |
| nextsi->prev = idx; |
| } |
| chainsi = unshare_strinfo (chainsi); |
| if (chainsi->first == 0) |
| chainsi->first = chainsi->idx; |
| chainsi->next = idx; |
| if (chainsi->endptr == NULL_TREE && zero_length_string_p (si)) |
| chainsi->endptr = ptr; |
| si->endptr = chainsi->endptr; |
| si->prev = chainsi->idx; |
| si->first = chainsi->first; |
| si->writable = chainsi->writable; |
| return si->idx; |
| } |
| |
| /* 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; |
| if (ssa_ver_to_stridx.length () <= SSA_NAME_VERSION (ptr)) |
| ssa_ver_to_stridx.safe_grow_cleared (num_ssa_names); |
| gcc_checking_assert (TREE_CODE (ptr) == SSA_NAME |
| && ssa_ver_to_stridx[SSA_NAME_VERSION (ptr)] == 0); |
| |
| if (SSA_NAME_OCCURS_IN_ABNORMAL_PHI (ptr)) |
| return NULL; |
| if (chainsi != NULL) |
| { |
| si = verify_related_strinfos (chainsi); |
| if (si) |
| { |
| do |
| { |
| /* We shouldn't mix delayed and non-delayed lengths. */ |
| gcc_assert (si->full_string_p); |
| if (si->endptr == NULL_TREE) |
| { |
| si = unshare_strinfo (si); |
| si->endptr = ptr; |
| } |
| chainsi = si; |
| si = get_next_strinfo (si); |
| } |
| while (si != NULL); |
| if (zero_length_string_p (chainsi)) |
| { |
| if (chainsi->next) |
| { |
| chainsi = unshare_strinfo (chainsi); |
| chainsi->next = 0; |
| } |
| ssa_ver_to_stridx[SSA_NAME_VERSION (ptr)] = chainsi->idx; |
| return chainsi; |
| } |
| } |
| else |
| { |
| /* We shouldn't mix delayed and non-delayed lengths. */ |
| gcc_assert (chainsi->full_string_p); |
| 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), true); |
| 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, adjust other |
| related strinfos so that they match the new ORIGSI. This involves: |
| |
| - adding ADJ to the nonzero_chars fields |
| - copying full_string_p from the new 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); |
| /* We shouldn't see delayed lengths here; the caller must have |
| calculated the old length in order to calculate the |
| adjustment. */ |
| gcc_assert (si->nonzero_chars); |
| tem = fold_convert_loc (loc, TREE_TYPE (si->nonzero_chars), adj); |
| si->nonzero_chars = fold_build2_loc (loc, PLUS_EXPR, |
| TREE_TYPE (si->nonzero_chars), |
| si->nonzero_chars, tem); |
| si->full_string_p = origsi->full_string_p; |
| |
| si->endptr = NULL_TREE; |
| si->dont_invalidate = true; |
| } |
| nsi = get_next_strinfo (si); |
| if (nsi == NULL) |
| 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 (ssa_ver_to_stridx.length () <= SSA_NAME_VERSION (ptr)) |
| ssa_ver_to_stridx.safe_grow_cleared (num_ssa_names); |
| |
| if (ssa_ver_to_stridx[SSA_NAME_VERSION (ptr)] != 0) |
| return; |
| ssa_ver_to_stridx[SSA_NAME_VERSION (ptr)] = idx; |
| } |
| } |
| |
| /* Return true if STMT is a call to a builtin function with the right |
| arguments and attributes that should be considered for optimization |
| by this pass. */ |
| |
| static bool |
| valid_builtin_call (gimple *stmt) |
| { |
| if (!gimple_call_builtin_p (stmt, BUILT_IN_NORMAL)) |
| return false; |
| |
| tree callee = gimple_call_fndecl (stmt); |
| switch (DECL_FUNCTION_CODE (callee)) |
| { |
| case BUILT_IN_MEMCMP: |
| case BUILT_IN_MEMCMP_EQ: |
| case BUILT_IN_STRCHR: |
| case BUILT_IN_STRCHR_CHKP: |
| case BUILT_IN_STRLEN: |
| case BUILT_IN_STRLEN_CHKP: |
| /* The above functions should be pure. Punt if they aren't. */ |
| if (gimple_vdef (stmt) || gimple_vuse (stmt) == NULL_TREE) |
| return false; |
| break; |
| |
| case BUILT_IN_CALLOC: |
| case BUILT_IN_MALLOC: |
| case BUILT_IN_MEMCPY: |
| case BUILT_IN_MEMCPY_CHK: |
| case BUILT_IN_MEMCPY_CHKP: |
| case BUILT_IN_MEMCPY_CHK_CHKP: |
| case BUILT_IN_MEMPCPY: |
| case BUILT_IN_MEMPCPY_CHK: |
| case BUILT_IN_MEMPCPY_CHKP: |
| case BUILT_IN_MEMPCPY_CHK_CHKP: |
| case BUILT_IN_MEMSET: |
| case BUILT_IN_STPCPY: |
| case BUILT_IN_STPCPY_CHK: |
| case BUILT_IN_STPCPY_CHKP: |
| case BUILT_IN_STPCPY_CHK_CHKP: |
| case BUILT_IN_STRCAT: |
| case BUILT_IN_STRCAT_CHK: |
| case BUILT_IN_STRCAT_CHKP: |
| case BUILT_IN_STRCAT_CHK_CHKP: |
| case BUILT_IN_STRCPY: |
| case BUILT_IN_STRCPY_CHK: |
| case BUILT_IN_STRCPY_CHKP: |
| case BUILT_IN_STRCPY_CHK_CHKP: |
| /* The above functions should be neither const nor pure. Punt if they |
| aren't. */ |
| if (gimple_vdef (stmt) == NULL_TREE || gimple_vuse (stmt) == NULL_TREE) |
| return false; |
| break; |
| |
| default: |
| break; |
| } |
| |
| return true; |
| } |
| |
| /* 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; |
| unsigned len_arg_no = 2; |
| |
| 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) |
| { |
| firstsi = get_next_strinfo (firstsi); |
| if (firstsi == NULL) |
| return; |
| } |
| } |
| |
| if (!is_strcat && !zero_length_string_p (si)) |
| 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 (!valid_builtin_call (last.stmt)) |
| return; |
| |
| callee = gimple_call_fndecl (last.stmt); |
| switch (DECL_FUNCTION_CODE (callee)) |
| { |
| case BUILT_IN_MEMCPY: |
| case BUILT_IN_MEMCPY_CHK: |
| break; |
| case BUILT_IN_MEMCPY_CHKP: |
| case BUILT_IN_MEMCPY_CHK_CHKP: |
| len_arg_no = 4; |
| break; |
| default: |
| return; |
| } |
| |
| len = gimple_call_arg (last.stmt, len_arg_no); |
| if (tree_fits_uhwi_p (len)) |
| { |
| if (!tree_fits_uhwi_p (last.len) |
| || integer_zerop (len) |
| || tree_to_uhwi (len) != tree_to_uhwi (last.len) + 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 ((tree_to_uhwi (len) & 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, len_arg_no, 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->nonzero_chars) != SSA_NAME |
| && TREE_CODE (si->nonzero_chars) != INTEGER_CST |
| && !SSA_NAME_OCCURS_IN_ABNORMAL_PHI (lhs)) |
| { |
| si = unshare_strinfo (si); |
| si->nonzero_chars = lhs; |
| gcc_assert (si->full_string_p); |
| } |
| |
| if (strlen_to_stridx) |
| { |
| location_t loc = gimple_location (stmt); |
| strlen_to_stridx->put (lhs, stridx_strlenloc (idx, loc)); |
| } |
| return; |
| } |
| } |
| if (SSA_NAME_OCCURS_IN_ABNORMAL_PHI (lhs)) |
| return; |
| if (idx == 0) |
| idx = new_stridx (src); |
| else |
| { |
| strinfo *si = get_strinfo (idx); |
| if (si != NULL) |
| { |
| if (!si->full_string_p && !si->stmt) |
| { |
| /* Until now we only had a lower bound on the string length. |
| Install LHS as the actual length. */ |
| si = unshare_strinfo (si); |
| tree old = si->nonzero_chars; |
| si->nonzero_chars = lhs; |
| si->full_string_p = true; |
| if (TREE_CODE (old) == INTEGER_CST) |
| { |
| location_t loc = gimple_location (stmt); |
| old = fold_convert_loc (loc, TREE_TYPE (lhs), old); |
| tree adj = fold_build2_loc (loc, MINUS_EXPR, |
| TREE_TYPE (lhs), lhs, old); |
| adjust_related_strinfos (loc, si, adj); |
| } |
| else |
| { |
| si->first = 0; |
| si->prev = 0; |
| si->next = 0; |
| } |
| } |
| return; |
| } |
| } |
| if (idx) |
| { |
| strinfo *si = new_strinfo (src, idx, lhs, true); |
| set_strinfo (idx, si); |
| find_equal_ptrs (src, idx); |
| |
| if (strlen_to_stridx) |
| { |
| location_t loc = gimple_location (stmt); |
| strlen_to_stridx->put (lhs, stridx_strlenloc (idx, loc)); |
| } |
| } |
| } |
| |
| /* 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); |
| bool with_bounds = gimple_call_with_bounds_p (stmt); |
| |
| if (lhs == NULL_TREE) |
| return; |
| |
| if (!integer_zerop (gimple_call_arg (stmt, with_bounds ? 2 : 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, true); |
| 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; |
| bool with_bounds = gimple_call_with_bounds_p (stmt); |
| |
| src = gimple_call_arg (stmt, with_bounds ? 2 : 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: |
| case BUILT_IN_STRCPY_CHKP: |
| case BUILT_IN_STRCPY_CHK_CHKP: |
| if (lhs != NULL_TREE || !builtin_decl_implicit_p (BUILT_IN_STPCPY)) |
| return; |
| break; |
| case BUILT_IN_STPCPY: |
| case BUILT_IN_STPCPY_CHK: |
| case BUILT_IN_STPCPY_CHKP: |
| case BUILT_IN_STPCPY_CHK_CHKP: |
| 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->nonzero_chars; |
| dsi = unshare_strinfo (olddsi); |
| dsi->nonzero_chars = srclen; |
| dsi->full_string_p = (srclen != NULL_TREE); |
| /* 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, srclen != NULL_TREE); |
| set_strinfo (didx, dsi); |
| find_equal_ptrs (dst, didx); |
| } |
| dsi->writable = true; |
| dsi->dont_invalidate = true; |
| |
| if (dsi->nonzero_chars == 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->nonzero_chars = NULL_TREE; |
| chainsi->full_string_p = false; |
| 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: |
| case BUILT_IN_STRCPY_CHKP: |
| fn = builtin_decl_implicit (BUILT_IN_MEMCPY); |
| if (lhs) |
| ssa_ver_to_stridx[SSA_NAME_VERSION (lhs)] = didx; |
| break; |
| case BUILT_IN_STRCPY_CHK: |
| case BUILT_IN_STRCPY_CHK_CHKP: |
| fn = builtin_decl_explicit (BUILT_IN_MEMCPY_CHK); |
| if (lhs) |
| ssa_ver_to_stridx[SSA_NAME_VERSION (lhs)] = didx; |
| break; |
| case BUILT_IN_STPCPY: |
| case BUILT_IN_STPCPY_CHKP: |
| /* 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: |
| case BUILT_IN_STPCPY_CHK_CHKP: |
| /* 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 (with_bounds) |
| { |
| fn = chkp_maybe_create_clone (fn)->decl; |
| if (gimple_call_num_args (stmt) == 4) |
| success = update_gimple_call (gsi, fn, 5, dst, |
| gimple_call_arg (stmt, 1), |
| src, |
| gimple_call_arg (stmt, 3), |
| len); |
| else |
| success = update_gimple_call (gsi, fn, 6, dst, |
| gimple_call_arg (stmt, 1), |
| src, |
| gimple_call_arg (stmt, 3), |
| len, |
| gimple_call_arg (stmt, 4)); |
| } |
| else |
| 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); |
| gimple_call_set_with_bounds (stmt, with_bounds); |
| 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"); |
| } |
| |
| /* Return true if LEN depends on a call to strlen(SRC) in an interesting |
| way. LEN can either be an integer expression, or a pointer (to char). |
| When it is the latter (such as in recursive calls to self) is is |
| assumed to be the argument in some call to strlen() whose relationship |
| to SRC is being ascertained. */ |
| |
| static bool |
| is_strlen_related_p (tree src, tree len) |
| { |
| if (TREE_CODE (TREE_TYPE (len)) == POINTER_TYPE |
| && operand_equal_p (src, len, 0)) |
| return true; |
| |
| if (TREE_CODE (len) != SSA_NAME) |
| return false; |
| |
| gimple *def_stmt = SSA_NAME_DEF_STMT (len); |
| if (!def_stmt) |
| return false; |
| |
| if (is_gimple_call (def_stmt)) |
| { |
| tree func = gimple_call_fndecl (def_stmt); |
| if (!valid_builtin_call (def_stmt) |
| || DECL_FUNCTION_CODE (func) != BUILT_IN_STRLEN) |
| return false; |
| |
| tree arg = gimple_call_arg (def_stmt, 0); |
| return is_strlen_related_p (src, arg); |
| } |
| |
| if (!is_gimple_assign (def_stmt)) |
| return false; |
| |
| tree_code code = gimple_assign_rhs_code (def_stmt); |
| tree rhs1 = gimple_assign_rhs1 (def_stmt); |
| tree rhstype = TREE_TYPE (rhs1); |
| |
| if ((TREE_CODE (rhstype) == POINTER_TYPE && code == POINTER_PLUS_EXPR) |
| || (INTEGRAL_TYPE_P (rhstype) |
| && (code == BIT_AND_EXPR |
| || code == NOP_EXPR))) |
| { |
| /* Pointer plus (an integer) and integer cast or truncation are |
| considered among the (potentially) related expressions to strlen. |
| Others are not. */ |
| return is_strlen_related_p (src, rhs1); |
| } |
| |
| return false; |
| } |
| |
| /* A helper of handle_builtin_stxncpy. Check to see if the specified |
| bound is a) equal to the size of the destination DST and if so, b) |
| if it's immediately followed by DST[CNT - 1] = '\0'. If a) holds |
| and b) does not, warn. Otherwise, do nothing. Return true if |
| diagnostic has been issued. |
| |
| The purpose is to diagnose calls to strncpy and stpncpy that do |
| not nul-terminate the copy while allowing for the idiom where |
| such a call is immediately followed by setting the last element |
| to nul, as in: |
| char a[32]; |
| strncpy (a, s, sizeof a); |
| a[sizeof a - 1] = '\0'; |
| */ |
| |
| static bool |
| maybe_diag_stxncpy_trunc (gimple_stmt_iterator gsi, tree src, tree cnt) |
| { |
| gimple *stmt = gsi_stmt (gsi); |
| |
| wide_int cntrange[2]; |
| |
| if (TREE_CODE (cnt) == INTEGER_CST) |
| cntrange[0] = cntrange[1] = wi::to_wide (cnt); |
| else if (TREE_CODE (cnt) == SSA_NAME) |
| { |
| enum value_range_type rng = get_range_info (cnt, cntrange, cntrange + 1); |
| if (rng == VR_RANGE) |
| ; |
| else if (rng == VR_ANTI_RANGE) |
| { |
| wide_int maxobjsize = wi::to_wide (TYPE_MAX_VALUE (ptrdiff_type_node)); |
| |
| if (wi::ltu_p (cntrange[1], maxobjsize)) |
| { |
| cntrange[0] = cntrange[1] + 1; |
| cntrange[1] = maxobjsize; |
| } |
| else |
| { |
| cntrange[1] = cntrange[0] - 1; |
| cntrange[0] = wi::zero (TYPE_PRECISION (TREE_TYPE (cnt))); |
| } |
| } |
| else |
| return false; |
| } |
| else |
| return false; |
| |
| /* Negative value is the constant string length. If it's less than |
| the lower bound there is no truncation. */ |
| int sidx = get_stridx (src); |
| if (sidx < 0 && wi::gtu_p (cntrange[0], ~sidx)) |
| return false; |
| |
| tree dst = gimple_call_arg (stmt, 0); |
| tree dstdecl = dst; |
| if (TREE_CODE (dstdecl) == ADDR_EXPR) |
| dstdecl = TREE_OPERAND (dstdecl, 0); |
| |
| /* If the destination refers to a an array/pointer declared nonstring |
| return early. */ |
| tree ref = NULL_TREE; |
| if (get_attr_nonstring_decl (dstdecl, &ref)) |
| return false; |
| |
| /* Look for dst[i] = '\0'; after the stxncpy() call and if found |
| avoid the truncation warning. */ |
| gsi_next (&gsi); |
| gimple *next_stmt = gsi_stmt (gsi); |
| |
| if (!gsi_end_p (gsi) && is_gimple_assign (next_stmt)) |
| { |
| tree lhs = gimple_assign_lhs (next_stmt); |
| tree_code code = TREE_CODE (lhs); |
| if (code == ARRAY_REF || code == MEM_REF) |
| lhs = TREE_OPERAND (lhs, 0); |
| |
| tree func = gimple_call_fndecl (stmt); |
| if (DECL_FUNCTION_CODE (func) == BUILT_IN_STPNCPY) |
| { |
| tree ret = gimple_call_lhs (stmt); |
| if (ret && operand_equal_p (ret, lhs, 0)) |
| return false; |
| } |
| |
| /* Determine the base address and offset of the reference, |
| ignoring the innermost array index. */ |
| if (TREE_CODE (ref) == ARRAY_REF) |
| ref = TREE_OPERAND (ref, 0); |
| |
| HOST_WIDE_INT dstoff; |
| tree dstbase = get_addr_base_and_unit_offset (ref, &dstoff); |
| |
| HOST_WIDE_INT lhsoff; |
| tree lhsbase = get_addr_base_and_unit_offset (lhs, &lhsoff); |
| if (lhsbase |
| && dstoff == lhsoff |
| && operand_equal_p (dstbase, lhsbase, 0)) |
| return false; |
| } |
| |
| int prec = TYPE_PRECISION (TREE_TYPE (cnt)); |
| wide_int lenrange[2]; |
| if (strinfo *sisrc = sidx > 0 ? get_strinfo (sidx) : NULL) |
| { |
| lenrange[0] = (sisrc->nonzero_chars |
| && TREE_CODE (sisrc->nonzero_chars) == INTEGER_CST |
| ? wi::to_wide (sisrc->nonzero_chars) |
| : wi::zero (prec)); |
| lenrange[1] = lenrange[0]; |
| } |
| else if (sidx < 0) |
| lenrange[0] = lenrange[1] = wi::shwi (~sidx, prec); |
| else |
| { |
| tree range[2]; |
| get_range_strlen (src, range); |
| if (range[0]) |
| { |
| lenrange[0] = wi::to_wide (range[0], prec); |
| lenrange[1] = wi::to_wide (range[1], prec); |
| } |
| else |
| { |
| lenrange[0] = wi::shwi (0, prec); |
| lenrange[1] = wi::shwi (-1, prec); |
| } |
| } |
| |
| location_t callloc = gimple_location (stmt); |
| tree func = gimple_call_fndecl (stmt); |
| |
| if (lenrange[0] != 0 || !wi::neg_p (lenrange[1])) |
| { |
| /* If the longest source string is shorter than the lower bound |
| of the specified count the copy is definitely nul-terminated. */ |
| if (wi::ltu_p (lenrange[1], cntrange[0])) |
| return false; |
| |
| if (wi::neg_p (lenrange[1])) |
| { |
| /* The length of one of the strings is unknown but at least |
| one has non-zero length and that length is stored in |
| LENRANGE[1]. Swap the bounds to force a "may be truncated" |
| warning below. */ |
| lenrange[1] = lenrange[0]; |
| lenrange[0] = wi::shwi (0, prec); |
| } |
| |
| if (wi::geu_p (lenrange[0], cntrange[1])) |
| { |
| /* The shortest string is longer than the upper bound of |
| the count so the truncation is certain. */ |
| if (cntrange[0] == cntrange[1]) |
| return warning_at (callloc, OPT_Wstringop_truncation, |
| integer_onep (cnt) |
| ? G_("%qD output truncated copying %E byte " |
| "from a string of length %wu") |
| : G_("%qD output truncated copying %E bytes " |
| "from a string of length %wu"), |
| func, cnt, lenrange[0].to_uhwi ()); |
| |
| return warning_at (callloc, OPT_Wstringop_truncation, |
| "%qD output truncated copying between %wu " |
| "and %wu bytes from a string of length %wu", |
| func, cntrange[0].to_uhwi (), |
| cntrange[1].to_uhwi (), lenrange[0].to_uhwi ()); |
| } |
| else if (wi::geu_p (lenrange[1], cntrange[1])) |
| { |
| /* The longest string is longer than the upper bound of |
| the count so the truncation is possible. */ |
| if (cntrange[0] == cntrange[1]) |
| return warning_at (callloc, OPT_Wstringop_truncation, |
| integer_onep (cnt) |
| ? G_("%qD output may be truncated copying %E " |
| "byte from a string of length %wu") |
| : G_("%qD output may be truncated copying %E " |
| "bytes from a string of length %wu"), |
| func, cnt, lenrange[1].to_uhwi ()); |
| |
| return warning_at (callloc, OPT_Wstringop_truncation, |
| "%qD output may be truncated copying between %wu " |
| "and %wu bytes from a string of length %wu", |
| func, cntrange[0].to_uhwi (), |
| cntrange[1].to_uhwi (), lenrange[1].to_uhwi ()); |
| } |
| |
| if (cntrange[0] != cntrange[1] |
| && wi::leu_p (cntrange[0], lenrange[0]) |
| && wi::leu_p (cntrange[1], lenrange[0] + 1)) |
| { |
| /* If the source (including the terminating nul) is longer than |
| the lower bound of the specified count but shorter than the |
| upper bound the copy may (but need not) be truncated. */ |
| return warning_at (callloc, OPT_Wstringop_truncation, |
| "%qD output may be truncated copying between %wu " |
| "and %wu bytes from a string of length %wu", |
| func, cntrange[0].to_uhwi (), |
| cntrange[1].to_uhwi (), lenrange[0].to_uhwi ()); |
| } |
| } |
| |
| if (tree dstsize = compute_objsize (dst, 1)) |
| { |
| /* The source length is uknown. Try to determine the destination |
| size and see if it matches the specified bound. If not, bail. |
| Otherwise go on to see if it should be diagnosed for possible |
| truncation. */ |
| if (!dstsize) |
| return false; |
| |
| if (wi::to_wide (dstsize) != cntrange[1]) |
| return false; |
| |
| if (cntrange[0] == cntrange[1]) |
| return warning_at (callloc, OPT_Wstringop_truncation, |
| "%qD specified bound %E equals destination size", |
| func, cnt); |
| } |
| |
| return false; |
| } |
| |
| /* Check the size argument to the built-in forms of stpncpy and strncpy |
| to see if it's derived from calling strlen() on the source argument |
| and if so, issue a warning. */ |
| |
| static void |
| handle_builtin_stxncpy (built_in_function, gimple_stmt_iterator *gsi) |
| { |
| if (!strlen_to_stridx) |
| return; |
| |
| gimple *stmt = gsi_stmt (*gsi); |
| |
| bool with_bounds = gimple_call_with_bounds_p (stmt); |
| |
| tree src = gimple_call_arg (stmt, with_bounds ? 2 : 1); |
| tree len = gimple_call_arg (stmt, with_bounds ? 3 : 2); |
| |
| /* If the length argument was computed from strlen(S) for some string |
| S retrieve the strinfo index for the string (PSS->FIRST) alonng with |
| the location of the strlen() call (PSS->SECOND). */ |
| stridx_strlenloc *pss = strlen_to_stridx->get (len); |
| if (!pss || pss->first <= 0) |
| { |
| if (maybe_diag_stxncpy_trunc (*gsi, src, len)) |
| gimple_set_no_warning (stmt, true); |
| |
| return; |
| } |
| |
| int sidx = get_stridx (src); |
| strinfo *sisrc = sidx > 0 ? get_strinfo (sidx) : NULL; |
| |
| /* Strncpy() et al. cannot modify the source string. Prevent the rest |
| of the pass from invalidating the strinfo data. */ |
| if (sisrc) |
| sisrc->dont_invalidate = true; |
| |
| /* Retrieve the strinfo data for the string S that LEN was computed |
| from as some function F of strlen (S) (i.e., LEN need not be equal |
| to strlen(S)). */ |
| strinfo *silen = get_strinfo (pss->first); |
| |
| location_t callloc = gimple_location (stmt); |
| |
| tree func = gimple_call_fndecl (stmt); |
| |
| bool warned = false; |
| |
| /* When -Wstringop-truncation is set, try to determine truncation |
| before diagnosing possible overflow. Truncation is implied by |
| the LEN argument being equal to strlen(SRC), regardless of |
| whether its value is known. Otherwise, issue the more generic |
| -Wstringop-overflow which triggers for LEN arguments that in |
| any meaningful way depend on strlen(SRC). */ |
| if (sisrc == silen |
| && is_strlen_related_p (src, len) |
| && warning_at (callloc, OPT_Wstringop_truncation, |
| "%qD output truncated before terminating nul " |
| "copying as many bytes from a string as its length", |
| func)) |
| warned = true; |
| else if (silen && is_strlen_related_p (src, silen->ptr)) |
| warned = warning_at (callloc, OPT_Wstringop_overflow_, |
| "%qD specified bound depends on the length " |
| "of the source argument", func); |
| if (warned) |
| { |
| location_t strlenloc = pss->second; |
| if (strlenloc != UNKNOWN_LOCATION && strlenloc != callloc) |
| inform (strlenloc, "length computed here"); |
| } |
| } |
| |
| /* Check the size argument to the built-in forms of strncat to see if |
| it's derived from calling strlen() on the source argument and if so, |
| issue a warning. */ |
| |
| static void |
| handle_builtin_strncat (built_in_function bcode, gimple_stmt_iterator *gsi) |
| { |
| /* Same as stxncpy(). */ |
| handle_builtin_stxncpy (bcode, gsi); |
| } |
| |
| /* 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; |
| bool with_bounds = gimple_call_with_bounds_p (stmt); |
| |
| len = gimple_call_arg (stmt, with_bounds ? 4 : 2); |
| src = gimple_call_arg (stmt, with_bounds ? 2 : 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 |
| && tree_fits_uhwi_p (len) |
| && !integer_zerop (len)) |
| adjust_last_stmt (olddsi, stmt, false); |
| |
| bool full_string_p; |
| if (idx > 0) |
| { |
| gimple *def_stmt; |
| |
| /* Handle memcpy (x, y, l) where l's relationship with strlen (y) |
| is known. */ |
| si = get_strinfo (idx); |
| if (si == NULL || si->nonzero_chars == NULL_TREE) |
| return; |
| if (TREE_CODE (len) == INTEGER_CST |
| && TREE_CODE (si->nonzero_chars) == INTEGER_CST) |
| { |
| if (tree_int_cst_le (len, si->nonzero_chars)) |
| { |
| /* Copying LEN nonzero characters, where LEN is constant. */ |
| newlen = len; |
| full_string_p = false; |
| } |
| else |
| { |
| /* Copying the whole of the analyzed part of SI. */ |
| newlen = si->nonzero_chars; |
| full_string_p = si->full_string_p; |
| } |
| } |
| else |
| { |
| if (!si->full_string_p) |
| 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->nonzero_chars |
| || !integer_onep (gimple_assign_rhs2 (def_stmt))) |
| return; |
| /* Copying variable-length string SI (and no more). */ |
| newlen = si->nonzero_chars; |
| full_string_p = true; |
| } |
| } |
| else |
| { |
| si = NULL; |
| /* Handle memcpy (x, "abcd", 5) or |
| memcpy (x, "abc\0uvw", 7). */ |
| if (!tree_fits_uhwi_p (len)) |
| return; |
| |
| unsigned HOST_WIDE_INT clen = tree_to_uhwi (len); |
| unsigned HOST_WIDE_INT nonzero_chars = ~idx; |
| newlen = build_int_cst (size_type_node, MIN (nonzero_chars, clen)); |
| full_string_p = clen > nonzero_chars; |
| } |
| |
| 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; |
| } |
| oldlen = NULL_TREE; |
| if (olddsi != NULL) |
| { |
| dsi = unshare_strinfo (olddsi); |
| oldlen = olddsi->nonzero_chars; |
| dsi->nonzero_chars = newlen; |
| dsi->full_string_p = full_string_p; |
| /* 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, full_string_p); |
| 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 = newlen; |
| else if (TREE_CODE (oldlen) == INTEGER_CST |
| || TREE_CODE (newlen) == INTEGER_CST) |
| adj = fold_build2_loc (loc, MINUS_EXPR, TREE_TYPE (newlen), newlen, |
| fold_convert_loc (loc, TREE_TYPE (newlen), |
| 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; |
| |
| if (full_string_p) |
| { |
| lhs = gimple_call_lhs (stmt); |
| switch (bcode) |
| { |
| case BUILT_IN_MEMCPY: |
| case BUILT_IN_MEMCPY_CHK: |
| case BUILT_IN_MEMCPY_CHKP: |
| case BUILT_IN_MEMCPY_CHK_CHKP: |
| /* Allow adjust_last_stmt to decrease this memcpy's size. */ |
| laststmt.stmt = stmt; |
| laststmt.len = dsi->nonzero_chars; |
| laststmt.stridx = dsi->idx; |
| if (lhs) |
| ssa_ver_to_stridx[SSA_NAME_VERSION (lhs)] = didx; |
| break; |
| case BUILT_IN_MEMPCPY: |
| case BUILT_IN_MEMPCPY_CHK: |
| case BUILT_IN_MEMPCPY_CHKP: |
| case BUILT_IN_MEMPCPY_CHK_CHKP: |
| 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; |
| bool with_bounds = gimple_call_with_bounds_p (stmt); |
| |
| src = gimple_call_arg (stmt, with_bounds ? 2 : 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, false); |
| set_strinfo (didx, dsi); |
| find_equal_ptrs (dst, didx); |
| } |
| else |
| { |
| dsi = unshare_strinfo (dsi); |
| dsi->nonzero_chars = NULL_TREE; |
| dsi->full_string_p = false; |
| 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->nonzero_chars; |
| endptr = dsi->endptr; |
| |
| dsi = unshare_strinfo (dsi); |
| dsi->endptr = NULL_TREE; |
| dsi->stmt = NULL; |
| dsi->writable = true; |
| |
| if (srclen != NULL_TREE) |
| { |
| dsi->nonzero_chars = fold_build2_loc (loc, PLUS_EXPR, |
| TREE_TYPE (dsi->nonzero_chars), |
| dsi->nonzero_chars, srclen); |
| gcc_assert (dsi->full_string_p); |
| adjust_related_strinfos (loc, dsi, srclen); |
| dsi->dont_invalidate = true; |
| } |
| else |
| { |
| dsi->nonzero_chars = NULL; |
| dsi->full_string_p = false; |
| 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: |
| case BUILT_IN_STRCAT_CHKP: |
| 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: |
| case BUILT_IN_STRCAT_CHK_CHKP: |
| 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, with_bounds ? 4 : 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 (with_bounds) |
| { |
| fn = chkp_maybe_create_clone (fn)->decl; |
| if (srclen != NULL_TREE) |
| success = update_gimple_call (gsi, fn, 5 + (objsz != NULL_TREE), |
| dst, |
| gimple_call_arg (stmt, 1), |
| src, |
| gimple_call_arg (stmt, 3), |
| len, objsz); |
| else |
| success = update_gimple_call (gsi, fn, 4 + (objsz != NULL_TREE), |
| dst, |
| gimple_call_arg (stmt, 1), |
| src, |
| gimple_call_arg (stmt, 3), |
| objsz); |
| } |
| else |
| 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); |
| gimple_call_set_with_bounds (stmt, with_bounds); |
| 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 call to malloc or calloc. */ |
| |
| static void |
| handle_builtin_malloc (enum built_in_function bcode, gimple_stmt_iterator *gsi) |
| { |
| gimple *stmt = gsi_stmt (*gsi); |
| tree lhs = gimple_call_lhs (stmt); |
| if (lhs == NULL_TREE) |
| return; |
| |
| gcc_assert (get_stridx (lhs) == 0); |
| int idx = new_stridx (lhs); |
| tree length = NULL_TREE; |
| if (bcode == BUILT_IN_CALLOC) |
| length = build_int_cst (size_type_node, 0); |
| strinfo *si = new_strinfo (lhs, idx, length, length != NULL_TREE); |
| if (bcode == BUILT_IN_CALLOC) |
| si->endptr = lhs; |
| set_strinfo (idx, si); |
| si->writable = true; |
| si->stmt = stmt; |
| si->dont_invalidate = true; |
| } |
| |
| /* Handle a call to memset. |
| After a call to calloc, memset(,0,) is unnecessary. |
| memset(malloc(n),0,n) is calloc(n,1). */ |
| |
| static bool |
| handle_builtin_memset (gimple_stmt_iterator *gsi) |
| { |
| gimple *stmt2 = gsi_stmt (*gsi); |
| if (!integer_zerop (gimple_call_arg (stmt2, 1))) |
| return true; |
| tree ptr = gimple_call_arg (stmt2, 0); |
| int idx1 = get_stridx (ptr); |
| if (idx1 <= 0) |
| return true; |
| strinfo *si1 = get_strinfo (idx1); |
| if (!si1) |
| return true; |
| gimple *stmt1 = si1->stmt; |
| if (!stmt1 || !is_gimple_call (stmt1)) |
| return true; |
| tree callee1 = gimple_call_fndecl (stmt1); |
| if (!valid_builtin_call (stmt1)) |
| return true; |
| enum built_in_function code1 = DECL_FUNCTION_CODE (callee1); |
| tree size = gimple_call_arg (stmt2, 2); |
| if (code1 == BUILT_IN_CALLOC) |
| /* Not touching stmt1 */ ; |
| else if (code1 == BUILT_IN_MALLOC |
| && operand_equal_p (gimple_call_arg (stmt1, 0), size, 0)) |
| { |
| gimple_stmt_iterator gsi1 = gsi_for_stmt (stmt1); |
| update_gimple_call (&gsi1, builtin_decl_implicit (BUILT_IN_CALLOC), 2, |
| size, build_one_cst (size_type_node)); |
| si1->nonzero_chars = build_int_cst (size_type_node, 0); |
| si1->full_string_p = true; |
| si1->stmt = gsi_stmt (gsi1); |
| } |
| else |
| return true; |
| tree lhs = gimple_call_lhs (stmt2); |
| unlink_stmt_vdef (stmt2); |
| if (lhs) |
| { |
| gimple *assign = gimple_build_assign (lhs, ptr); |
| gsi_replace (gsi, assign, false); |
| } |
| else |
| { |
| gsi_remove (gsi, true); |
| release_defs (stmt2); |
| } |
| |
| return false; |
| } |
| |
| /* Handle a call to memcmp. We try to handle small comparisons by |
| converting them to load and compare, and replacing the call to memcmp |
| with a __builtin_memcmp_eq call where possible. */ |
| |
| static bool |
| handle_builtin_memcmp (gimple_stmt_iterator *gsi) |
| { |
| gcall *stmt2 = as_a <gcall *> (gsi_stmt (*gsi)); |
| tree res = gimple_call_lhs (stmt2); |
| tree arg1 = gimple_call_arg (stmt2, 0); |
| tree arg2 = gimple_call_arg (stmt2, 1); |
| tree len = gimple_call_arg (stmt2, 2); |
| unsigned HOST_WIDE_INT leni; |
| use_operand_p use_p; |
| imm_use_iterator iter; |
| |
| if (!res) |
| return true; |
| |
| FOR_EACH_IMM_USE_FAST (use_p, iter, res) |
| { |
| gimple *ustmt = USE_STMT (use_p); |
| |
| if (is_gimple_debug (ustmt)) |
| continue; |
| if (gimple_code (ustmt) == GIMPLE_ASSIGN) |
| { |
| gassign *asgn = as_a <gassign *> (ustmt); |
| tree_code code = gimple_assign_rhs_code (asgn); |
| if ((code != EQ_EXPR && code != NE_EXPR) |
| || !integer_zerop (gimple_assign_rhs2 (asgn))) |
| return true; |
| } |
| else if (gimple_code (ustmt) == GIMPLE_COND) |
| { |
| tree_code code = gimple_cond_code (ustmt); |
| if ((code != EQ_EXPR && code != NE_EXPR) |
| || !integer_zerop (gimple_cond_rhs (ustmt))) |
| return true; |
| } |
| else |
| return true; |
| } |
| |
| if (tree_fits_uhwi_p (len) |
| && (leni = tree_to_uhwi (len)) <= GET_MODE_SIZE (word_mode) |
| && pow2p_hwi (leni)) |
| { |
| leni *= CHAR_TYPE_SIZE; |
| unsigned align1 = get_pointer_alignment (arg1); |
| unsigned align2 = get_pointer_alignment (arg2); |
| unsigned align = MIN (align1, align2); |
| scalar_int_mode mode; |
| if (int_mode_for_size (leni, 1).exists (&mode) |
| && (align >= leni || !targetm.slow_unaligned_access (mode, align))) |
| { |
| location_t loc = gimple_location (stmt2); |
| tree type, off; |
| type = build_nonstandard_integer_type (leni, 1); |
| gcc_assert (GET_MODE_BITSIZE (TYPE_MODE (type)) == leni); |
| tree ptrtype = build_pointer_type_for_mode (char_type_node, |
| ptr_mode, true); |
| off = build_int_cst (ptrtype, 0); |
| arg1 = build2_loc (loc, MEM_REF, type, arg1, off); |
| arg2 = build2_loc (loc, MEM_REF, type, arg2, off); |
| tree tem1 = fold_const_aggregate_ref (arg1); |
| if (tem1) |
| arg1 = tem1; |
| tree tem2 = fold_const_aggregate_ref (arg2); |
| if (tem2) |
| arg2 = tem2; |
| res = fold_convert_loc (loc, TREE_TYPE (res), |
| fold_build2_loc (loc, NE_EXPR, |
| boolean_type_node, |
| arg1, arg2)); |
| gimplify_and_update_call_from_tree (gsi, res); |
| return false; |
| } |
| } |
| |
| gimple_call_set_fndecl (stmt2, builtin_decl_explicit (BUILT_IN_MEMCMP_EQ)); |
| return false; |
| } |
| |
| /* 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 (tree_fits_uhwi_p (off) |
| && tree_to_uhwi (off) <= (unsigned HOST_WIDE_INT) ~idx) |
| ssa_ver_to_stridx[SSA_NAME_VERSION (lhs)] |
| = ~(~idx - (int) tree_to_uhwi (off)); |
| return; |
| } |
| |
| si = get_strinfo (idx); |
| if (si == NULL || si->nonzero_chars == NULL_TREE) |
| return; |
| |
| off = gimple_assign_rhs2 (stmt); |
| zsi = NULL; |
| if (si->full_string_p && operand_equal_p (si->nonzero_chars, 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) |
| && si->full_string_p |
| && operand_equal_p (si->nonzero_chars, |
| 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); |
| 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); |
| tree rhs = gimple_assign_rhs1 (stmt); |
| unsigned HOST_WIDE_INT offset = 0; |
| |
| if (TREE_CODE (lhs) == MEM_REF |
| && TREE_CODE (TREE_OPERAND (lhs, 0)) == SSA_NAME) |
| { |
| tree mem_offset = TREE_OPERAND (lhs, 1); |
| if (tree_fits_uhwi_p (mem_offset)) |
| { |
| /* Get the strinfo for the base, and use it if it starts with at |
| least OFFSET nonzero characters. This is trivially true if |
| OFFSET is zero. */ |
| offset = tree_to_uhwi (mem_offset); |
| idx = get_stridx (TREE_OPERAND (lhs, 0)); |
| if (idx > 0) |
| si = get_strinfo (idx); |
| if (offset == 0) |
| ssaname = TREE_OPERAND (lhs, 0); |
| else if (si == NULL || compare_nonzero_chars (si, offset) < 0) |
| return true; |
| } |
| } |
| else |
| { |
| idx = get_addr_stridx (lhs, NULL_TREE, &offset); |
| if (idx > 0) |
| si = get_strinfo (idx); |
| } |
| |
| bool storing_zero_p = initializer_zerop (rhs); |
| bool storing_nonzero_p = (!storing_zero_p |
| && TREE_CODE (rhs) == INTEGER_CST |
| && integer_nonzerop (rhs)); |
| |
| if (si != NULL) |
| { |
| int cmp = compare_nonzero_chars (si, offset); |
| gcc_assert (offset == 0 || cmp >= 0); |
| if (storing_zero_p && cmp == 0 && si->full_string_p) |
| { |
| /* When overwriting a '\0' with a '\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; |
| gsi_next (gsi); |
| return false; |
| } |
| } |
| /* If si->nonzero_chars > OFFSET, we aren't overwriting '\0', |
| and if we aren't storing '\0', we know that the length of the |
| string and any other zero terminated string in memory remains |
| the same. In that case we move to the next gimple statement and |
| return to signal the caller that it shouldn't invalidate anything. |
| |
| This is benefical for cases like: |
| |
| char p[20]; |
| void foo (char *q) |
| { |
| strcpy (p, "foobar"); |
| size_t len = strlen (p); // This can be optimized into 6 |
| size_t len2 = strlen (q); // This has to be computed |
| p[0] = 'X'; |
| size_t len3 = strlen (p); // This can be optimized into 6 |
| size_t len4 = strlen (q); // This can be optimized into len2 |
| bar (len, len2, len3, len4); |
| } |
| */ |
| else if (storing_nonzero_p && cmp > 0) |
| { |
| gsi_next (gsi); |
| return false; |
| } |
| else if (storing_zero_p || storing_nonzero_p || (offset != 0 && cmp > 0)) |
| { |
| /* When storing_nonzero_p, we know that the string now starts |
| with OFFSET + 1 nonzero characters, but don't know whether |
| there's a following nul terminator. |
| |
| When storing_zero_p, we know that the string is now OFFSET |
| characters long. |
| |
| Otherwise, we're storing an unknown value at offset OFFSET, |
| so need to clip the nonzero_chars to OFFSET. */ |
| location_t loc = gimple_location (stmt); |
| tree oldlen = si->nonzero_chars; |
| if (cmp == 0 && si->full_string_p) |
| /* We're overwriting the nul terminator with a nonzero or |
| unknown character. If the previous stmt was a memcpy, |
| its length may be decreased. */ |
| adjust_last_stmt (si, stmt, false); |
| si = unshare_strinfo (si); |
| if (storing_nonzero_p) |
| si->nonzero_chars = build_int_cst (size_type_node, offset + 1); |
| else |
| si->nonzero_chars = build_int_cst (size_type_node, offset); |
| si->full_string_p = storing_zero_p; |
| if (storing_zero_p |
| && ssaname |
| && !SSA_NAME_OCCURS_IN_ABNORMAL_PHI (ssaname)) |
| si->endptr = ssaname; |
| else |
| si->endptr = NULL; |
| si->next = 0; |
| si->stmt = NULL; |
| si->writable = true; |
| si->dont_invalidate = true; |
| if (oldlen) |
| { |
| tree adj = fold_build2_loc (loc, MINUS_EXPR, size_type_node, |
| si->nonzero_chars, oldlen); |
| adjust_related_strinfos (loc, si, adj); |
| } |
| else |
| si->prev = 0; |
| } |
| } |
| else if (idx == 0 && (storing_zero_p || storing_nonzero_p)) |
| { |
| if (ssaname) |
| idx = new_stridx (ssaname); |
| else |
| idx = new_addr_stridx (lhs); |
| if (idx != 0) |
| { |
| tree ptr = (ssaname ? ssaname : build_fold_addr_expr (lhs)); |
| tree len = storing_nonzero_p ? size_one_node : size_zero_node; |
| si = new_strinfo (ptr, idx, len, storing_zero_p); |
| set_strinfo (idx, si); |
| if (storing_zero_p |
| && ssaname |
| && !SSA_NAME_OCCURS_IN_ABNORMAL_PHI (ssaname)) |
| si->endptr = ssaname; |
| si->dont_invalidate = true; |
| si->writable = true; |
| } |
| } |
| else if (idx == 0 |
| && TREE_CODE (gimple_assign_rhs1 (stmt)) == STRING_CST |
| && ssaname == NULL_TREE |
| && TREE_CODE (TREE_TYPE (lhs)) == ARRAY_TYPE) |
| { |
| size_t l = strlen (TREE_STRING_POINTER (gimple_assign_rhs1 (stmt))); |
| HOST_WIDE_INT a = int_size_in_bytes (TREE_TYPE (lhs)); |
| if (a > 0 && (unsigned HOST_WIDE_INT) a > l) |
| { |
| int idx = new_addr_stridx (lhs); |
| if (idx != 0) |
| { |
| si = new_strinfo (build_fold_addr_expr (lhs), idx, |
| build_int_cst (size_type_node, l), true); |
| set_strinfo (idx, si); |
| si->dont_invalidate = true; |
| } |
| } |
| } |
| |
| if (si != NULL && offset == 0 && storing_zero_p) |
| { |
| /* 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; |
| } |
| |
| /* Try to fold strstr (s, t) eq/ne s to strncmp (s, t, strlen (t)) eq/ne 0. */ |
| |
| static void |
| fold_strstr_to_strncmp (tree rhs1, tree rhs2, gimple *stmt) |
| { |
| if (TREE_CODE (rhs1) != SSA_NAME |
| || TREE_CODE (rhs2) != SSA_NAME) |
| return; |
| |
| gimple *call_stmt = NULL; |
| for (int pass = 0; pass < 2; pass++) |
| { |
| gimple *g = SSA_NAME_DEF_STMT (rhs1); |
| if (gimple_call_builtin_p (g, BUILT_IN_STRSTR) |
| && has_single_use (rhs1) |
| && gimple_call_arg (g, 0) == rhs2) |
| { |
| call_stmt = g; |
| break; |
| } |
| std::swap (rhs1, rhs2); |
| } |
| |
| if (call_stmt) |
| { |
| tree arg0 = gimple_call_arg (call_stmt, 0); |
| |
| if (arg0 == rhs2) |
| { |
| tree arg1 = gimple_call_arg (call_stmt, 1); |
| tree arg1_len = NULL_TREE; |
| int idx = get_stridx (arg1); |
| |
| if (idx) |
| { |
| if (idx < 0) |
| arg1_len = build_int_cst (size_type_node, ~idx); |
| else |
| { |
| strinfo *si = get_strinfo (idx); |
| if (si) |
| arg1_len = get_string_length (si); |
| } |
| } |
| |
| if (arg1_len != NULL_TREE) |
| { |
| gimple_stmt_iterator gsi = gsi_for_stmt (call_stmt); |
| tree strncmp_decl = builtin_decl_explicit (BUILT_IN_STRNCMP); |
| gcall *strncmp_call = gimple_build_call (strncmp_decl, 3, |
| arg0, arg1, arg1_len); |
| tree strncmp_lhs = make_ssa_name (integer_type_node); |
| gimple_set_vuse (strncmp_call, gimple_vuse (call_stmt)); |
| gimple_call_set_lhs (strncmp_call, strncmp_lhs); |
| gsi_remove (&gsi, true); |
| gsi_insert_before (&gsi, strncmp_call, GSI_SAME_STMT); |
| tree zero = build_zero_cst (TREE_TYPE (strncmp_lhs)); |
| |
| if (is_gimple_assign (stmt)) |
| { |
| if (gimple_assign_rhs_code (stmt) == COND_EXPR) |
| { |
| tree cond = gimple_assign_rhs1 (stmt); |
| TREE_OPERAND (cond, 0) = strncmp_lhs; |
| TREE_OPERAND (cond, 1) = zero; |
| } |
| else |
| { |
| gimple_assign_set_rhs1 (stmt, strncmp_lhs); |
| gimple_assign_set_rhs2 (stmt, zero); |
| } |
| } |
| else |
| { |
| gcond *cond = as_a<gcond *> (stmt); |
| gimple_cond_set_lhs (cond, strncmp_lhs); |
| gimple_cond_set_rhs (cond, zero); |
| } |
| update_stmt (stmt); |
| } |
| } |
| } |
| } |
| |
| /* 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 (valid_builtin_call (stmt)) |
| switch (DECL_FUNCTION_CODE (callee)) |
| { |
| case BUILT_IN_STRLEN: |
| case BUILT_IN_STRLEN_CHKP: |
| handle_builtin_strlen (gsi); |
| break; |
| case BUILT_IN_STRCHR: |
| case BUILT_IN_STRCHR_CHKP: |
| handle_builtin_strchr (gsi); |
| break; |
| case BUILT_IN_STRCPY: |
| case BUILT_IN_STRCPY_CHK: |
| case BUILT_IN_STPCPY: |
| case BUILT_IN_STPCPY_CHK: |
| case BUILT_IN_STRCPY_CHKP: |
| case BUILT_IN_STRCPY_CHK_CHKP: |
| case BUILT_IN_STPCPY_CHKP: |
| case BUILT_IN_STPCPY_CHK_CHKP: |
| handle_builtin_strcpy (DECL_FUNCTION_CODE (callee), gsi); |
| break; |
| |
| case BUILT_IN_STRNCAT: |
| case BUILT_IN_STRNCAT_CHK: |
| handle_builtin_strncat (DECL_FUNCTION_CODE (callee), gsi); |
| break; |
| |
| case BUILT_IN_STPNCPY: |
| case BUILT_IN_STPNCPY_CHK: |
| case BUILT_IN_STRNCPY: |
| case BUILT_IN_STRNCPY_CHK: |
| handle_builtin_stxncpy (DECL_FUNCTION_CODE (callee), gsi); |
| break; |
| |
| case BUILT_IN_MEMCPY: |
| case BUILT_IN_MEMCPY_CHK: |
| case BUILT_IN_MEMPCPY: |
| case BUILT_IN_MEMPCPY_CHK: |
| case BUILT_IN_MEMCPY_CHKP: |
| case BUILT_IN_MEMCPY_CHK_CHKP: |
| case BUILT_IN_MEMPCPY_CHKP: |
| case BUILT_IN_MEMPCPY_CHK_CHKP: |
| handle_builtin_memcpy (DECL_FUNCTION_CODE (callee), gsi); |
| break; |
| case BUILT_IN_STRCAT: |
| case BUILT_IN_STRCAT_CHK: |
| case BUILT_IN_STRCAT_CHKP: |
| case BUILT_IN_STRCAT_CHK_CHKP: |
| handle_builtin_strcat (DECL_FUNCTION_CODE (callee), gsi); |
| break; |
| case BUILT_IN_MALLOC: |
| case BUILT_IN_CALLOC: |
| handle_builtin_malloc (DECL_FUNCTION_CODE (callee), gsi); |
| break; |
| case BUILT_IN_MEMSET: |
| if (!handle_builtin_memset (gsi)) |
| return false; |
| break; |
| case BUILT_IN_MEMCMP: |
| if (!handle_builtin_memcmp (gsi)) |
| return false; |
| break; |
| default: |
| break; |
| } |
| } |
| else if (is_gimple_assign (stmt) && !gimple_clobber_p (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)); |
| 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 && INTEGRAL_TYPE_P (TREE_TYPE (lhs))) |
| { |
| enum tree_code code = gimple_assign_rhs_code (stmt); |
| if (code == COND_EXPR) |
| { |
| tree cond = gimple_assign_rhs1 (stmt); |
| enum tree_code cond_code = TREE_CODE (cond); |
| |
| if (cond_code == EQ_EXPR || cond_code == NE_EXPR) |
| fold_strstr_to_strncmp (TREE_OPERAND (cond, 0), |
| TREE_OPERAND (cond, 1), stmt); |
| } |
| else if (code == EQ_EXPR || code == NE_EXPR) |
| fold_strstr_to_strncmp (gimple_assign_rhs1 (stmt), |
| gimple_assign_rhs2 (stmt), stmt); |
| |
| if (strlen_to_stridx) |
| { |
| tree rhs1 = gimple_assign_rhs1 (stmt); |
| if (stridx_strlenloc *ps = strlen_to_stridx->get (rhs1)) |
| strlen_to_stridx->put (lhs, stridx_strlenloc (*ps)); |
| } |
| } |
| 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; |
| } |
| } |
| } |
| else if (gcond *cond = dyn_cast<gcond *> (stmt)) |
| { |
| enum tree_code code = gimple_cond_code (cond); |
| if (code == EQ_EXPR || code == NE_EXPR) |
| fold_strstr_to_strncmp (gimple_cond_lhs (stmt), |
| gimple_cond_rhs (stmt), stmt); |
| } |
| |
| 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) |
| { |
|