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| author | Bernd Edlinger <bernd.edlinger@hotmail.de> | 2018-09-14 01:49:38 +0000 |
|---|---|---|
| committer | Jeff Law <law@gcc.gnu.org> | 2018-09-13 19:49:38 -0600 |
| commit | d01b568a78351beb6b693b613e6b48bcb2475eae (patch) | |
| tree | bd7da348cd6459bb6656e42300e83dcf9f2ac2c2 /gcc/builtins.c | |
| parent | 9a9f692b6c0c8b93b7fda00c60c6e30c2e6551ce (diff) | |
| download | gcc-d01b568a78351beb6b693b613e6b48bcb2475eae.zip gcc-d01b568a78351beb6b693b613e6b48bcb2475eae.tar.gz gcc-d01b568a78351beb6b693b613e6b48bcb2475eae.tar.bz2 | |
builtins.c (c_strlen): Handle not zero terminated STRING_CSTs correctly.
* builtins.c (c_strlen): Handle not zero terminated STRING_CSTs
correctly.
* fold-const.c (c_getstr): Fix function comment. Remove unused third
argument. Fix range checks.
* fold-const.h (c_getstr): Adjust protoype.
* gimple-fold.c (gimple_fold_builtin_memory_op): Avoid folding when
string is constant but contains no NUL byte.
From-SVN: r264301
Diffstat (limited to 'gcc/builtins.c')
| -rw-r--r-- | gcc/builtins.c | 22 |
1 files changed, 11 insertions, 11 deletions
diff --git a/gcc/builtins.c b/gcc/builtins.c index 58ea747..bef3ad2 100644 --- a/gcc/builtins.c +++ b/gcc/builtins.c @@ -604,12 +604,12 @@ c_strlen (tree src, int only_value, unsigned eltsize) In that case, the elements of the array after the terminating NUL are all NUL. */ HOST_WIDE_INT strelts = TREE_STRING_LENGTH (src); - strelts = strelts / eltsize - 1; + strelts = strelts / eltsize; if (!tree_fits_uhwi_p (memsize)) return NULL_TREE; - HOST_WIDE_INT maxelts = tree_to_uhwi (memsize) / eltsize - 1; + HOST_WIDE_INT maxelts = tree_to_uhwi (memsize) / eltsize; /* PTR can point to the byte representation of any string type, including char* and wchar_t*. */ @@ -617,10 +617,6 @@ c_strlen (tree src, int only_value, unsigned eltsize) if (byteoff && TREE_CODE (byteoff) != INTEGER_CST) { - /* For empty strings the result should be zero. */ - if (maxelts == 0) - return ssize_int (0); - /* The code below works only for single byte character types. */ if (eltsize != 1) return NULL_TREE; @@ -632,9 +628,13 @@ c_strlen (tree src, int only_value, unsigned eltsize) unsigned len = string_length (ptr, eltsize, strelts); /* Return when an embedded null character is found or none at all. */ - if (len < strelts || len > maxelts) + if (len + 1 < strelts || len >= maxelts) return NULL_TREE; + /* For empty strings the result should be zero. */ + if (len == 0) + return ssize_int (0); + /* We don't know the starting offset, but we do know that the string has no internal zero bytes. If the offset falls within the bounds of the string subtract the offset from the length of the string, @@ -644,7 +644,7 @@ c_strlen (tree src, int only_value, unsigned eltsize) offsave = fold_convert (ssizetype, offsave); tree condexp = fold_build2_loc (loc, LE_EXPR, boolean_type_node, offsave, build_int_cst (ssizetype, len)); - tree lenexp = size_diffop_loc (loc, ssize_int (strelts), offsave); + tree lenexp = size_diffop_loc (loc, ssize_int (len), offsave); return fold_build3_loc (loc, COND_EXPR, ssizetype, condexp, lenexp, build_zero_cst (ssizetype)); } @@ -663,7 +663,7 @@ c_strlen (tree src, int only_value, unsigned eltsize) /* If the offset is known to be out of bounds, warn, and call strlen at runtime. */ - if (eltoff < 0 || eltoff > maxelts) + if (eltoff < 0 || eltoff >= maxelts) { /* Suppress multiple warnings for propagated constant strings. */ if (only_value != 2 @@ -691,9 +691,9 @@ c_strlen (tree src, int only_value, unsigned eltsize) unsigned len = string_length (ptr + eltoff * eltsize, eltsize, strelts - eltoff); - /* Don't know what to return if there was no zero termination. + /* Don't know what to return if there was no zero termination. Ideally this would turn into a gcc_checking_assert over time. */ - if (len > maxelts - eltoff) + if (len >= maxelts - eltoff) return NULL_TREE; return ssize_int (len); |