diff options
Diffstat (limited to 'gcc/fold-const.c')
| -rw-r--r-- | gcc/fold-const.c | 58 |
1 files changed, 46 insertions, 12 deletions
diff --git a/gcc/fold-const.c b/gcc/fold-const.c index 5b94c70..97c435f 100644 --- a/gcc/fold-const.c +++ b/gcc/fold-const.c @@ -14546,14 +14546,19 @@ fold_build_pointer_plus_hwi_loc (location_t loc, tree ptr, HOST_WIDE_INT off) ptr, size_int (off)); } -/* Return a char pointer for a C string if it is a string constant - or sum of string constant and integer constant. We only support - string constants properly terminated with '\0' character. - If STRLEN is a valid pointer, length (including terminating character) - of returned string is stored to the argument. */ +/* Return a pointer P to a NUL-terminated string representing the sequence + of constant characters referred to by SRC (or a subsequence of such + characters within it if SRC is a reference to a string plus some + constant offset). If STRLEN is non-null, store stgrlen(P) in *STRLEN. + If STRSIZE is non-null, store in *STRSIZE the size of the array + the string is stored in; in that case, even though P points to a NUL + terminated string, SRC need not refer to one. This can happen when + SRC refers to a constant character array initialized to all non-NUL + values, as in the C declaration: char a[4] = "1234"; */ const char * -c_getstr (tree src, unsigned HOST_WIDE_INT *strlen) +c_getstr (tree src, unsigned HOST_WIDE_INT *strlen /* = NULL */, + unsigned HOST_WIDE_INT *strsize /* = NULL */) { tree offset_node; @@ -14573,18 +14578,47 @@ c_getstr (tree src, unsigned HOST_WIDE_INT *strlen) offset = tree_to_uhwi (offset_node); } + /* STRING_LENGTH is the size of the string literal, including any + embedded NULs. STRING_SIZE is the size of the array the string + literal is stored in. */ unsigned HOST_WIDE_INT string_length = TREE_STRING_LENGTH (src); + unsigned HOST_WIDE_INT string_size = string_length; + tree type = TREE_TYPE (src); + if (tree size = TYPE_SIZE_UNIT (type)) + if (tree_fits_shwi_p (size)) + string_size = tree_to_uhwi (size); + + if (strlen) + { + /* Compute and store the length of the substring at OFFSET. + All offsets past the initial length refer to null strings. */ + if (offset <= string_length) + *strlen = string_length - offset; + else + *strlen = 0; + } + const char *string = TREE_STRING_POINTER (src); - /* Support only properly null-terminated strings. */ if (string_length == 0 - || string[string_length - 1] != '\0' - || offset >= string_length) + || offset >= string_size) return NULL; - if (strlen) - *strlen = string_length - offset; - return string + offset; + if (strsize) + { + /* Support even constant character arrays that aren't proper + NUL-terminated strings. */ + *strsize = string_size; + } + else if (string[string_length - 1] != '\0') + { + /* Support only properly NUL-terminated strings but handle + consecutive strings within the same array, such as the six + substrings in "1\0002\0003". */ + return NULL; + } + + return offset <= string_length ? string + offset : ""; } /* Given a tree T, compute which bits in T may be nonzero. */ |