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| author | Jakub Jelinek <jakub@redhat.com> | 2023-03-17 16:10:14 +0100 |
|---|---|---|
| committer | Jakub Jelinek <jakub@redhat.com> | 2023-03-17 16:10:14 +0100 |
| commit | 103d423f6ce72ccb03d55b7b1dfa2dabd5854371 (patch) | |
| tree | e522e6af56d03357381d2ff7deba0aca243521e7 /gcc | |
| parent | 6bfb5eae96b65894da1301e966568fdf32bf64d0 (diff) | |
| download | gcc-103d423f6ce72ccb03d55b7b1dfa2dabd5854371.zip gcc-103d423f6ce72ccb03d55b7b1dfa2dabd5854371.tar.gz gcc-103d423f6ce72ccb03d55b7b1dfa2dabd5854371.tar.bz2 | |
c, ubsan: Instrument even shortened divisions [PR109151]
On the following testcase, the C FE decides to shorten the division because
it has a guarantee that INT_MIN / -1 division won't be encountered, the
first operand is widened from narrower unsigned and/or the second operand is
a constant other than all ones (in this case both are true).
The problem is that the narrower type in this case is _Bool and
ubsan_instrument_division only instruments it if op0's type is INTEGER_TYPE
or REAL_TYPE. Strangely this doesn't happen in C++ FE.
Anyway, we only shorten divisions if the INT_MIN / -1 case is impossible,
so I think we should be fine even with -fstrict-enums in C++ in case it
shortened to ENUMERAL_TYPEs.
The following patch just instruments those on the ubsan_instrument_division
side. Perhaps only the first hunk and testcase might be needed because
we shouldn't shorten if the other case could be triggered.
2023-03-17 Jakub Jelinek <jakub@redhat.com>
PR c/109151
* c-ubsan.cc (ubsan_instrument_division): Handle all scalar integral
types rather than just INTEGER_TYPE.
* c-c++-common/ubsan/div-by-zero-8.c: New test.
Diffstat (limited to 'gcc')
| -rw-r--r-- | gcc/c-family/c-ubsan.cc | 4 | ||||
| -rw-r--r-- | gcc/testsuite/c-c++-common/ubsan/div-by-zero-8.c | 14 |
2 files changed, 16 insertions, 2 deletions
diff --git a/gcc/c-family/c-ubsan.cc b/gcc/c-family/c-ubsan.cc index 3e24198..c3ae515 100644 --- a/gcc/c-family/c-ubsan.cc +++ b/gcc/c-family/c-ubsan.cc @@ -53,7 +53,7 @@ ubsan_instrument_division (location_t loc, tree op0, tree op1) op0 = unshare_expr (op0); op1 = unshare_expr (op1); - if (TREE_CODE (type) == INTEGER_TYPE + if (INTEGRAL_TYPE_P (type) && sanitize_flags_p (SANITIZE_DIVIDE)) t = fold_build2 (EQ_EXPR, boolean_type_node, op1, build_int_cst (type, 0)); @@ -68,7 +68,7 @@ ubsan_instrument_division (location_t loc, tree op0, tree op1) t = NULL_TREE; /* We check INT_MIN / -1 only for signed types. */ - if (TREE_CODE (type) == INTEGER_TYPE + if (INTEGRAL_TYPE_P (type) && sanitize_flags_p (SANITIZE_SI_OVERFLOW) && !TYPE_UNSIGNED (type)) { diff --git a/gcc/testsuite/c-c++-common/ubsan/div-by-zero-8.c b/gcc/testsuite/c-c++-common/ubsan/div-by-zero-8.c new file mode 100644 index 0000000..02e1d7c --- /dev/null +++ b/gcc/testsuite/c-c++-common/ubsan/div-by-zero-8.c @@ -0,0 +1,14 @@ +/* PR c/109151 */ +/* { dg-do run } */ +/* { dg-options "-fsanitize=integer-divide-by-zero -Wno-div-by-zero -fno-sanitize-recover=integer-divide-by-zero" } */ +/* { dg-shouldfail "ubsan" } */ + +int d; + +int +main () +{ + d = ((short) (d == 1 | d > 9)) / 0; +} + +/* { dg-output "division by zero" } */ |