testing for tail call optimization repression when sanitizing use-after-dtor

[nmusgrave]

Summary

Verify that running in optimized mode while checking for use-after-dtor errors, does not generate tail call invocation of destructor. This avoids possible error where stack frame for the destructor is eliminated, making tracking down the errors more difficult.

[eugenis]

test/msan/dtor-tail-call.cc

36

Use @LINE to refer to line numbers in the test case.

38

You don't need a 'CHECK-OPT' if it's the same as 'CHECK'

42

Don't refer to the line numbers in other files, they will change.
In this case it would be ok to end the line after __sanitizer_dtor_callback}}

[nmusgrave]

• simplified test cases

[nmusgrave]

• updated line numbering on test

[eugenis]

LGTM

Please rename the test to "use-after-dtor.cc". It's not really about tail calls, it's a general test of the use-after-dtor report.

test/msan/dtor-tail-call.cc

4

Add a test at -O2

35

Maybe remove the space after "main" to make this more robust, in case, on some other platform, the symbolizer would add () after main.

39

Remove () for the same reason

[nmusgrave]

• simplified test cases
• updated line numbering on test
• renamed test

test/msan/dtor-tail-call.cc

+// RUN: %clangxx_msan %s -fsanitize=memory -fsanitize-memory-use-after-dtor -o %t && MSAN_OPTIONS=poison_in_dtor=1 not %run %t >%t.out 2>&1
+// RUN: FileCheck %s < %t.out
+
+// RUN: %clangxx_msan %s -O1 -fsanitize=memory -fsanitize-memory-use-after-dtor -o %t && MSAN_OPTIONS=poison_in_dtor=1 not %run %t >%t.out 2>&1
+// RUN: FileCheck %s < %t.out
+
+// RUN: %clangxx_msan %s -O1 -fsanitize=memory -fsanitize-memory-use-after-dtor -fsanitize-memory-track-origins -o %t && MSAN_OPTIONS=poison_in_dtor=1 not %run %t >%t.out 2>&1
+// RUN: FileCheck %s --check-prefix=CHECK-ORIGINS < %t.out
+
+#include <sanitizer/msan_interface.h>
+#include <assert.h>
+#include <stdio.h>
+#include <new>
+
+struct Simple {
+  int x_;
+  Simple() {
+    x_ = 5;
+  }
+  ~Simple() {
+    x_ += 1;
+  }
+};
+
+int main() {
+  unsigned long buf[1];
+  assert(sizeof(Simple) <= sizeof(buf));
+
+  Simple *s = new(&buf) Simple();
+  s->~Simple();
+
+  return s->x_;
+
+  // CHECK: WARNING: MemorySanitizer: use-of-uninitialized-value
+  // CHECK: {{#0 0x.* in main .*dtor-tail-call.cc:}}[[@LINE-3]]
+
+  // CHECK-ORIGINS: Memory was marked as uninitialized
+  // CHECK-ORIGINS: {{#0 0x.* in __sanitizer_dtor_callback}}
+  // CHECK-ORIGINS: {{#1 0x.* in Simple::~Simple()}}
+
+  // CHECK: SUMMARY: MemorySanitizer: use-of-uninitialized-value {{.*main}}
+}