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* [gcc r11-8489] builtins: Fix ICE with unprototyped builtin call [PR100576]
@ 2021-05-31 14:08 Jakub Jelinek
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From: Jakub Jelinek @ 2021-05-31 14:08 UTC (permalink / raw)
To: gcc-cvs
https://gcc.gnu.org/g:f4d6ea0c64bbbbe45add18294bfbd2ceb6512bbd
commit r11-8489-gf4d6ea0c64bbbbe45add18294bfbd2ceb6512bbd
Author: Jakub Jelinek <jakub@redhat.com>
Date: Wed May 19 12:05:30 2021 +0200
builtins: Fix ICE with unprototyped builtin call [PR100576]
For unprototyped builtins the checking we perform is only about whether
the used argument is integral, pointer etc., not the exact precision.
We emit a warning about the problem though:
pr100576.c: In function ‘foo’:
pr100576.c:9:11: warning: implicit declaration of function ‘memcmp’ [-Wimplicit-function-declaration]
9 | int n = memcmp (p, v, b);
| ^~~~~~
pr100576.c:1:1: note: include ‘<string.h>’ or provide a declaration of ‘memcmp’
+++ |+#include <string.h>
1 | /* PR middle-end/100576 */
pr100576.c:9:25: warning: ‘memcmp’ argument 3 type is ‘int’ where ‘long unsigned int’ is expected in a call to built-in function declared without prototype
+[-Wbuiltin-declaration-mismatch]
9 | int n = memcmp (p, v, b);
| ^
It means in the testcase below where the user incorrectly called memcmp
with last argument int rather then size_t, the warning stuff in builtins.c
ICEs because it compares a wide_int from such a bound with another wide_int
which has precision of size_t/sizetype and wide_int asserts the compared
wide_ints are compatible.
Fixed by forcing the bound to have the right type.
2021-05-19 Jakub Jelinek <jakub@redhat.com>
PR middle-end/100576
* builtins.c (check_read_access): Convert bound to size_type_node if
non-NULL.
* gcc.c-torture/compile/pr100576.c: New test.
(cherry picked from commit e6683450f4a26dae7774be735a3429f48aee9565)
Diff:
---
gcc/builtins.c | 2 ++
gcc/testsuite/gcc.c-torture/compile/pr100576.c | 12 ++++++++++++
2 files changed, 14 insertions(+)
diff --git a/gcc/builtins.c b/gcc/builtins.c
index d30c4eb62fc..308846ee39b 100644
--- a/gcc/builtins.c
+++ b/gcc/builtins.c
@@ -4910,6 +4910,8 @@ check_read_access (tree exp, tree src, tree bound /* = NULL_TREE */,
if (!warn_stringop_overread)
return true;
+ if (bound && !useless_type_conversion_p (size_type_node, TREE_TYPE (bound)))
+ bound = fold_convert (size_type_node, bound);
access_data data (exp, access_read_only, NULL_TREE, false, bound, true);
compute_objsize (src, ost, &data.src);
return check_access (exp, /*dstwrite=*/ NULL_TREE, /*maxread=*/ bound,
diff --git a/gcc/testsuite/gcc.c-torture/compile/pr100576.c b/gcc/testsuite/gcc.c-torture/compile/pr100576.c
new file mode 100644
index 00000000000..f2f40ec4512
--- /dev/null
+++ b/gcc/testsuite/gcc.c-torture/compile/pr100576.c
@@ -0,0 +1,12 @@
+/* PR middle-end/100576 */
+
+const char v[] = {0x12};
+
+void
+foo (const char *p)
+{
+ int b = sizeof v;
+ int n = memcmp (p, v, b);
+ if (n)
+ __builtin_abort ();
+}
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