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authorJakub Jelinek <jakub@redhat.com>2020-09-22 21:06:32 +0200
committerJakub Jelinek <jakub@redhat.com>2020-09-22 21:08:02 +0200
commitbc13106e0414b86af8f6878e7681e6a959921b9e (patch)
tree0d5cd7575d2446eb14fd507d7791cf9f9cbbe234
parent49ff88bd0d8a36a9e903f01ce05685cfe07dee5d (diff)
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c++: Ignore __sanitizer_ptr_{sub,cmp} builtin calls during constant expression evaluation [PR97145]
These two builtin calls are added already during parsing before pointer subtractions or comparisons, normally they perform runtime verification of whether the pointers point to the same object or different objects, but during constant expressione valuation we don't really need those builtins for anything. 2020-09-22 Jakub Jelinek <jakub@redhat.com> PR c++/97145 * constexpr.c (cxx_eval_builtin_function_call): Return void_node for calls to __sanitize_ptr_{sub,cmp} builtins. * g++.dg/asan/pr97145.C: New test.
-rw-r--r--gcc/cp/constexpr.c6
-rw-r--r--gcc/testsuite/g++.dg/asan/pr97145.C7
2 files changed, 13 insertions, 0 deletions
diff --git a/gcc/cp/constexpr.c b/gcc/cp/constexpr.c
index 72fbdab..dacce58 100644
--- a/gcc/cp/constexpr.c
+++ b/gcc/cp/constexpr.c
@@ -1355,6 +1355,12 @@ cxx_eval_builtin_function_call (const constexpr_ctx *ctx, tree t, tree fun,
case BUILT_IN_STRSTR:
strops = 2;
strret = 1;
+ break;
+ case BUILT_IN_ASAN_POINTER_COMPARE:
+ case BUILT_IN_ASAN_POINTER_SUBTRACT:
+ /* These builtins shall be ignored during constant expression
+ evaluation. */
+ return void_node;
default:
break;
}
diff --git a/gcc/testsuite/g++.dg/asan/pr97145.C b/gcc/testsuite/g++.dg/asan/pr97145.C
new file mode 100644
index 0000000..993c8a5
--- /dev/null
+++ b/gcc/testsuite/g++.dg/asan/pr97145.C
@@ -0,0 +1,7 @@
+// PR c++/97145
+// { dg-do compile { target c++11 } }
+// { dg-options "-fsanitize=address,pointer-subtract,pointer-compare" }
+
+constexpr char *a = nullptr;
+constexpr auto b = a - a;
+constexpr auto c = a < a;