[ubsan] Disable bounds-check for flexible array ivars

This eliminates a class of false positives for -fsanitize=array-bounds
on instrumented ObjC projects.

Differential Revision: https://reviews.llvm.org/D22227

llvm-svn: 283249

1 files changed, 59 insertions, 0 deletions

diff --git a/clang/test/CodeGenObjC/ubsan-array-bounds.m b/clang/test/CodeGenObjC/ubsan-array-bounds.m
new file mode 100644
index 00000000000..38d1eb310d2
--- /dev/null
+++ b/clang/test/CodeGenObjC/ubsan-array-bounds.m
@@ -0,0 +1,59 @@
+// RUN: %clang_cc1 -x objective-c -emit-llvm -triple x86_64-apple-macosx10.10.0 -Wno-objc-root-class -fsanitize=array-bounds %s -o - | FileCheck %s
+
+@interface FlexibleArray1 {
+@public
+  char chars[0];
+}
+@end
+@implementation FlexibleArray1
+@end
+
+// CHECK-LABEL: test_FlexibleArray1
+char test_FlexibleArray1(FlexibleArray1 *FA1) {
+  // CHECK-NOT: !nosanitize
+  return FA1->chars[1];
+  // CHECK: }
+}
+
+@interface FlexibleArray2 {
+@public
+  char chars[0];
+}
+@end
+@implementation FlexibleArray2 {
+@public
+  char chars2[0];
+}
+@end
+
+// CHECK-LABEL: test_FlexibleArray2_1
+char test_FlexibleArray2_1(FlexibleArray2 *FA2) {
+  // CHECK: !nosanitize
+  return FA2->chars[1];
+  // CHECK: }
+}
+
+// CHECK-LABEL: test_FlexibleArray2_2
+char test_FlexibleArray2_2(FlexibleArray2 *FA2) {
+  // CHECK-NOT: !nosanitize
+  return FA2->chars2[1];
+  // CHECK: }
+}
+
+@interface FlexibleArray3 {
+@public
+  char chars[0];
+}
+@end
+@implementation FlexibleArray3 {
+@public
+  int i;
+}
+@end
+
+// CHECK-LABEL: test_FlexibleArray3
+char test_FlexibleArray3(FlexibleArray3 *FA3) {
+  // CHECK: !nosanitize
+  return FA3->chars[1];
+  // CHECK: }
+}