diff options
Diffstat (limited to 'gcc/c-family/c-common.c')
| -rw-r--r-- | gcc/c-family/c-common.c | 143 |
1 files changed, 143 insertions, 0 deletions
diff --git a/gcc/c-family/c-common.c b/gcc/c-family/c-common.c index ab3eb0a..502613a 100644 --- a/gcc/c-family/c-common.c +++ b/gcc/c-family/c-common.c @@ -1841,6 +1841,149 @@ strict_aliasing_warning (tree otype, tree type, tree expr) return false; } +/* Warn about memset (&a, 0, sizeof (&a)); and similar mistakes with + sizeof as last operand of certain builtins. */ + +void +sizeof_pointer_memaccess_warning (location_t loc, tree callee, + VEC(tree, gc) *params, tree sizeof_arg, + bool (*comp_types) (tree, tree)) +{ + tree type, dest = NULL_TREE, src = NULL_TREE, tem; + bool strop = false; + + if (TREE_CODE (callee) != FUNCTION_DECL + || DECL_BUILT_IN_CLASS (callee) != BUILT_IN_NORMAL + || sizeof_arg == error_mark_node + || VEC_length (tree, params) <= 1) + return; + + type = TYPE_P (sizeof_arg) ? sizeof_arg : TREE_TYPE (sizeof_arg); + if (!POINTER_TYPE_P (type)) + return; + + switch (DECL_FUNCTION_CODE (callee)) + { + case BUILT_IN_STRNCMP: + case BUILT_IN_STRNCASECMP: + case BUILT_IN_STRNCPY: + case BUILT_IN_STRNCAT: + strop = true; + /* FALLTHRU */ + case BUILT_IN_MEMCPY: + case BUILT_IN_MEMMOVE: + case BUILT_IN_MEMCMP: + if (VEC_length (tree, params) < 3) + return; + src = VEC_index (tree, params, 1); + dest = VEC_index (tree, params, 0); + break; + case BUILT_IN_MEMSET: + if (VEC_length (tree, params) < 3) + return; + dest = VEC_index (tree, params, 0); + break; + case BUILT_IN_STRNDUP: + src = VEC_index (tree, params, 0); + strop = true; + break; + default: + break; + } + + if (dest + && (tem = tree_strip_nop_conversions (dest)) + && POINTER_TYPE_P (TREE_TYPE (tem)) + && comp_types (TREE_TYPE (TREE_TYPE (tem)), type)) + return; + + if (src + && (tem = tree_strip_nop_conversions (src)) + && POINTER_TYPE_P (TREE_TYPE (tem)) + && comp_types (TREE_TYPE (TREE_TYPE (tem)), type)) + return; + + if (dest) + { + if (!TYPE_P (sizeof_arg) + && operand_equal_p (dest, sizeof_arg, 0) + && comp_types (TREE_TYPE (dest), type)) + { + if (TREE_CODE (sizeof_arg) == ADDR_EXPR && !strop) + warning_at (loc, OPT_Wsizeof_pointer_memaccess, + "argument to %<sizeof%> in %qD call is the same " + "expression as the destination; did you mean to " + "remove the addressof?", callee); + else if ((TYPE_PRECISION (TREE_TYPE (type)) + == TYPE_PRECISION (char_type_node)) + || strop) + warning_at (loc, OPT_Wsizeof_pointer_memaccess, + "argument to %<sizeof%> in %qD call is the same " + "expression as the destination; did you mean to " + "provide an explicit length?", callee); + else + warning_at (loc, OPT_Wsizeof_pointer_memaccess, + "argument to %<sizeof%> in %qD call is the same " + "expression as the destination; did you mean to " + "dereference it?", callee); + return; + } + + if (POINTER_TYPE_P (TREE_TYPE (dest)) + && !strop + && comp_types (TREE_TYPE (dest), type) + && !VOID_TYPE_P (TREE_TYPE (type))) + { + warning_at (loc, OPT_Wsizeof_pointer_memaccess, + "argument to %<sizeof%> in %qD call is the same " + "pointer type %qT as the destination; expected %qT " + "or an explicit length", callee, TREE_TYPE (dest), + TREE_TYPE (TREE_TYPE (dest))); + return; + } + } + + if (src) + { + if (!TYPE_P (sizeof_arg) + && operand_equal_p (src, sizeof_arg, 0) + && comp_types (TREE_TYPE (src), type)) + { + if (TREE_CODE (sizeof_arg) == ADDR_EXPR && !strop) + warning_at (loc, OPT_Wsizeof_pointer_memaccess, + "argument to %<sizeof%> in %qD call is the same " + "expression as the source; did you mean to " + "remove the addressof?", callee); + else if ((TYPE_PRECISION (TREE_TYPE (type)) + == TYPE_PRECISION (char_type_node)) + || strop) + warning_at (loc, OPT_Wsizeof_pointer_memaccess, + "argument to %<sizeof%> in %qD call is the same " + "expression as the source; did you mean to " + "provide an explicit length?", callee); + else + warning_at (loc, OPT_Wsizeof_pointer_memaccess, + "argument to %<sizeof%> in %qD call is the same " + "expression as the source; did you mean to " + "dereference it?", callee); + return; + } + + if (POINTER_TYPE_P (TREE_TYPE (src)) + && !strop + && comp_types (TREE_TYPE (src), type) + && !VOID_TYPE_P (TREE_TYPE (type))) + { + warning_at (loc, OPT_Wsizeof_pointer_memaccess, + "argument to %<sizeof%> in %qD call is the same " + "pointer type %qT as the source; expected %qT " + "or an explicit length", callee, TREE_TYPE (src), + TREE_TYPE (TREE_TYPE (src))); + return; + } + } +} + /* Warn for unlikely, improbable, or stupid DECL declarations of `main'. */ |