1 files changed, 34 insertions, 0 deletions
diff --git a/test/msan/msan_copy_shadow.cc b/test/msan/msan_copy_shadow.cc
new file mode 100644
index 000000000000..a1c6347ff4e3
--- /dev/null
+++ b/test/msan/msan_copy_shadow.cc
@@ -0,0 +1,34 @@
+// Test that __msan_copy_shadow copies shadow, updates origin and does not touch
+// the application memory.
+// RUN: %clangxx_msan -fsanitize-memory-track-origins=0 -O0 %s -o %t && not %run %t 2>&1
+// RUN: %clangxx_msan -fsanitize-memory-track-origins=2 -O0 %s -o %t && not %run %t 2>&1 | FileCheck %s
+
+#include <assert.h>
+#include <string.h>
+#include <sanitizer/msan_interface.h>
+
+int main() {
+  char *a = new char[4];
+  char *b = new char[4];
+  a[1] = 1;
+  a[3] = 2;
+  memset(b, 42, 4);
+
+  // Test that __msan_copy_shadow does not touch the contents of b[].
+  __msan_copy_shadow(b, a, 4);
+  __msan_unpoison(b, 4);
+  assert(b[0] == 42 && b[1] == 42 && b[2] == 42 && b[3] == 42);
+
+  // Test that __msan_copy_shadow correctly updates shadow and origin of b[].
+  __msan_copy_shadow(b, a, 4);
+  assert(__msan_test_shadow(b, 4) == 0);
+  assert(__msan_test_shadow(b + 1, 3) == 1);
+  assert(__msan_test_shadow(b + 3, 1) == -1);
+  __msan_check_mem_is_initialized(b, 4);
+  // CHECK: use-of-uninitialized-value
+  // CHECK:   {{in main.*msan_copy_shadow.cc:}}[[@LINE-2]]
+  // CHECK: Uninitialized value was stored to memory at
+  // CHECK:   {{in main.*msan_copy_shadow.cc:}}[[@LINE-8]]
+  // CHECK: Uninitialized value was created by a heap allocation
+  // CHECK:   {{in main.*msan_copy_shadow.cc:}}[[@LINE-22]]
+}