diff options
Diffstat (limited to 'gcc/tree-ssa-strlen.c')
| -rw-r--r-- | gcc/tree-ssa-strlen.c | 122 |
1 files changed, 72 insertions, 50 deletions
diff --git a/gcc/tree-ssa-strlen.c b/gcc/tree-ssa-strlen.c index ff32301..48b9241 100644 --- a/gcc/tree-ssa-strlen.c +++ b/gcc/tree-ssa-strlen.c @@ -51,6 +51,7 @@ along with GCC; see the file COPYING3. If not see #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 @@ -152,8 +153,11 @@ struct decl_stridxlist_map 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; +static hash_map<tree, stridx_strlenloc> *strlen_to_stridx; /* Obstack for struct stridxlist and struct decl_stridxlist_map. */ static struct obstack stridx_obstack; @@ -1207,8 +1211,11 @@ handle_builtin_strlen (gimple_stmt_iterator *gsi) gcc_assert (si->full_string_p); } - location_t loc = gimple_location (stmt); - strlen_to_stridx.put (lhs, stridx_strlenloc (idx, loc)); + if (strlen_to_stridx) + { + location_t loc = gimple_location (stmt); + strlen_to_stridx->put (lhs, stridx_strlenloc (idx, loc)); + } return; } } @@ -1253,8 +1260,11 @@ handle_builtin_strlen (gimple_stmt_iterator *gsi) set_strinfo (idx, si); find_equal_ptrs (src, idx); - location_t loc = gimple_location (stmt); - strlen_to_stridx.put (lhs, stridx_strlenloc (idx, loc)); + if (strlen_to_stridx) + { + location_t loc = gimple_location (stmt); + strlen_to_stridx->put (lhs, stridx_strlenloc (idx, loc)); + } } } @@ -1691,9 +1701,6 @@ is_strlen_related_p (tree src, tree len) static bool maybe_diag_stxncpy_trunc (gimple_stmt_iterator gsi, tree src, tree cnt) { - if (!warn_stringop_truncation) - return false; - gimple *stmt = gsi_stmt (gsi); wide_int cntrange[2]; @@ -1733,35 +1740,15 @@ maybe_diag_stxncpy_trunc (gimple_stmt_iterator gsi, tree src, tree cnt) return false; tree dst = gimple_call_arg (stmt, 0); - - /* See if the destination is declared with attribute "nonstring" - and if so, avoid the truncation warning. */ - if (TREE_CODE (dst) == SSA_NAME) - { - if (SSA_NAME_IS_DEFAULT_DEF (dst)) - dst = SSA_NAME_VAR (dst); - else - { - gimple *def = SSA_NAME_DEF_STMT (dst); - - if (is_gimple_assign (def) - && gimple_assign_rhs_code (def) == ADDR_EXPR) - dst = gimple_assign_rhs1 (def); - } - } - tree dstdecl = dst; if (TREE_CODE (dstdecl) == ADDR_EXPR) dstdecl = TREE_OPERAND (dstdecl, 0); - { - tree d = dstdecl; - if (TREE_CODE (d) == COMPONENT_REF) - d = TREE_OPERAND (d, 1); - - if (DECL_P (d) && lookup_attribute ("nonstring", DECL_ATTRIBUTES (d))) - return false; - } + /* 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. */ @@ -1770,12 +1757,32 @@ maybe_diag_stxncpy_trunc (gimple_stmt_iterator gsi, tree src, tree cnt) if (!gsi_end_p (gsi) && is_gimple_assign (next_stmt)) { - HOST_WIDE_INT off; - dstdecl = get_addr_base_and_unit_offset (dstdecl, &off); - tree lhs = gimple_assign_lhs (next_stmt); - tree lhsbase = get_addr_base_and_unit_offset (lhs, &off); - if (lhsbase && operand_equal_p (dstdecl, lhsbase, 0)) + 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; } @@ -1909,6 +1916,9 @@ maybe_diag_stxncpy_trunc (gimple_stmt_iterator gsi, tree src, tree cnt) 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); @@ -1919,7 +1929,7 @@ handle_builtin_stxncpy (built_in_function, gimple_stmt_iterator *gsi) /* 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); + stridx_strlenloc *pss = strlen_to_stridx->get (len); if (!pss || pss->first <= 0) { if (maybe_diag_stxncpy_trunc (*gsi, src, len)) @@ -1953,13 +1963,13 @@ handle_builtin_stxncpy (built_in_function, gimple_stmt_iterator *gsi) 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 (warn_stringop_truncation - && sisrc == silen - && is_strlen_related_p (src, len)) - warned = warning_at (callloc, OPT_Wstringop_truncation, - "%qD output truncated before terminating nul " - "copying as many bytes from a string as its length", - func); + 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 " @@ -2966,9 +2976,12 @@ strlen_optimize_stmt (gimple_stmt_iterator *gsi) fold_strstr_to_strncmp (gimple_assign_rhs1 (stmt), gimple_assign_rhs2 (stmt), stmt); - tree rhs1 = gimple_assign_rhs1 (stmt); - if (stridx_strlenloc *ps = strlen_to_stridx.get (rhs1)) - strlen_to_stridx.put (lhs, stridx_strlenloc (*ps)); + 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)) { @@ -3199,6 +3212,10 @@ public: unsigned int pass_strlen::execute (function *fun) { + gcc_assert (!strlen_to_stridx); + if (warn_stringop_overflow || warn_stringop_truncation) + strlen_to_stridx = new hash_map<tree, stridx_strlenloc> (); + ssa_ver_to_stridx.safe_grow_cleared (num_ssa_names); max_stridx = 1; @@ -3220,7 +3237,12 @@ pass_strlen::execute (function *fun) laststmt.len = NULL_TREE; laststmt.stridx = 0; - strlen_to_stridx.empty (); + if (strlen_to_stridx) + { + strlen_to_stridx->empty (); + delete strlen_to_stridx; + strlen_to_stridx = NULL; + } return 0; } |