diff options
| author | mpolacek <mpolacek@138bc75d-0d04-0410-961f-82ee72b054a4> | 2017-09-04 11:30:26 +0000 |
|---|---|---|
| committer | mpolacek <mpolacek@138bc75d-0d04-0410-961f-82ee72b054a4> | 2017-09-04 11:30:26 +0000 |
| commit | 16414c649cbf1dbc4fa45db8f896a636840787d2 (patch) | |
| tree | 9b9eb5195184349428955b9bc16261b81fef83bb /gcc/convert.c | |
| parent | f5e1594f88313b8122dd83ec0c9eac199316becc (diff) | |
| download | gcc-16414c649cbf1dbc4fa45db8f896a636840787d2.tar.gz | |
PR sanitizer/82072
* convert.c (do_narrow): When sanitizing signed integer overflows,
bail out for signed types.
(convert_to_integer_1) <case NEGATE_EXPR>: Likewise.
* c-c++-common/ubsan/pr82072.c: New test.
git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@251651 138bc75d-0d04-0410-961f-82ee72b054a4
Diffstat (limited to 'gcc/convert.c')
| -rw-r--r-- | gcc/convert.c | 14 |
1 files changed, 13 insertions, 1 deletions
diff --git a/gcc/convert.c b/gcc/convert.c index 22152cae79b..139d790fd98 100644 --- a/gcc/convert.c +++ b/gcc/convert.c @@ -434,6 +434,13 @@ do_narrow (location_t loc, typex = lang_hooks.types.type_for_size (TYPE_PRECISION (typex), TYPE_UNSIGNED (typex)); + /* The type demotion below might cause doing unsigned arithmetic + instead of signed, and thus hide overflow bugs. */ + if ((ex_form == PLUS_EXPR || ex_form == MINUS_EXPR) + && !TYPE_UNSIGNED (typex) + && sanitize_flags_p (SANITIZE_SI_OVERFLOW)) + return NULL_TREE; + /* But now perhaps TYPEX is as wide as INPREC. In that case, do nothing special here. (Otherwise would recurse infinitely in convert. */ @@ -895,7 +902,12 @@ convert_to_integer_1 (tree type, tree expr, bool dofold) TYPE_UNSIGNED (typex)); if (!TYPE_UNSIGNED (typex)) - typex = unsigned_type_for (typex); + { + /* Using unsigned arithmetic may hide overflow bugs. */ + if (sanitize_flags_p (SANITIZE_SI_OVERFLOW)) + break; + typex = unsigned_type_for (typex); + } return convert (type, fold_build1 (ex_form, typex, convert (typex, |