[asan] Fix a false positive ODR violation due to LTO ConstantMerge pass [compiler...

This fixes a false positive ODR violation that is reported by ASan when using LTO. In cases, where two constant globals have the same value, LTO will merge them, which breaks ASan's ODR detection. See the included testcase for an example.

Differential Revision: https://reviews.llvm.org/D43959

llvm-svn: 327062

diff --git a/compiler-rt/test/asan/TestCases/Darwin/odr-lto.cc b/compiler-rt/test/asan/TestCases/Darwin/odr-lto.cc
index 40abec5..56dd89b 100644 (file)
--- a/compiler-rt/test/asan/TestCases/Darwin/odr-lto.cc
+++ b/compiler-rt/test/asan/TestCases/Darwin/odr-lto.cc
@@ -3,15 +3,10 @@
 
 // REQUIRES: lto
 
-// RUN: %clangxx_asan -DPART=0 -c %s -o %t-1.o -flto
-// RUN: %clangxx_asan -DPART=1 -c %s -o %t-2.o -flto
-// RUN: %clangxx_asan %t-1.o %t-2.o -o %t -flto
-// RUN: not %run %t 2>&1 | FileCheck %s --check-prefix=CHECK-ODR
-
 // RUN: %clangxx_asan -DPART=0 -c %s -o %t-1.o -flto -mllvm -asan-use-private-alias
 // RUN: %clangxx_asan -DPART=1 -c %s -o %t-2.o -flto -mllvm -asan-use-private-alias
 // RUN: %clangxx_asan %t-1.o %t-2.o -o %t -flto
-// RUN: %env_asan_opts=use_odr_indicator=1 %run %t 2>&1 | FileCheck %s --check-prefix=CHECK-NO-ODR
+// RUN: %env_asan_opts=use_odr_indicator=1 %run %t 2>&1 | FileCheck %s
 
 #include <stdio.h>
 #include <stdlib.h>
@@ -40,6 +35,5 @@ void putstest()
 
 #endif // PART == 1
 
-// CHECK-ODR: ERROR: AddressSanitizer: odr-violation
-// CHECK-NO-ODR-NOT: ERROR: AddressSanitizer: odr-violation
-// CHECK-NO-ODR: Done.
+// CHECK-NOT: ERROR: AddressSanitizer: odr-violation
+// CHECK: Done.

diff --git a/compiler-rt/test/asan/TestCases/lto-constmerge-odr.cc b/compiler-rt/test/asan/TestCases/lto-constmerge-odr.cc
new file mode 100644 (file)
index 0000000..9dc1397
--- /dev/null
+++ b/compiler-rt/test/asan/TestCases/lto-constmerge-odr.cc
@@ -0,0 +1,14 @@
+// RUN: %clangxx_asan -O3 -flto %s -o %t
+// RUN: %run %t 2>&1
+
+// REQUIRES: lto
+
+int main(int argc, const char * argv[]) {
+  struct { long width, height; } a = {16, 16};
+  struct { long width, height; } b = {16, 16};
+
+  // Just to make sure 'a' and 'b' don't get optimized out.
+  asm volatile("" : : "r" (&a), "r" (&b));
+
+  return 0;
+}