Improve collecting malloc stats in ASan

Summary:
This change makes races between updates of thread-local stats and
merging all the thread-local stats together less harmful.

Reviewers: kcc

Reviewed By: kcc

CC: dvyukov, llvm-commits

Differential Revision: http://llvm-reviews.chandlerc.com/D1572

git-svn-id: https://llvm.org/svn/llvm-project/compiler-rt/trunk@189744 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 43 insertions, 0 deletions

diff --git a/lib/asan/lit_tests/TestCases/current_allocated_bytes.cc b/lib/asan/lit_tests/TestCases/current_allocated_bytes.cc
new file mode 100644
index 00000000..669cf150
--- /dev/null
+++ b/lib/asan/lit_tests/TestCases/current_allocated_bytes.cc
@@ -0,0 +1,43 @@
+// RUN: %clangxx_asan -O0 %s -o %t && %t
+// RUN: %clangxx_asan -O2 %s -o %t && %t
+
+#include <assert.h>
+#include <pthread.h>
+#include <sanitizer/asan_interface.h>
+#include <stdio.h>
+#include <stdlib.h>
+
+const size_t kLargeAlloc = 1UL << 20;
+
+void* allocate(void *arg) {
+  volatile void *ptr = malloc(kLargeAlloc);
+  free((void*)ptr);
+  return 0;
+}
+
+void* check_stats(void *arg) {
+  assert(__asan_get_current_allocated_bytes() > 0);
+  return 0;
+}
+
+int main() {
+  size_t used_mem = __asan_get_current_allocated_bytes();
+  printf("Before: %zu\n", used_mem);
+  const int kNumIterations = 1000;
+  for (int iter = 0; iter < kNumIterations; iter++) {
+    pthread_t thr[4];
+    for (int j = 0; j < 4; j++) {
+      assert(0 ==
+             pthread_create(&thr[j], 0, (j < 2) ? allocate : check_stats, 0));
+    }
+    for (int j = 0; j < 4; j++)
+      assert(0 == pthread_join(thr[j], 0));
+    used_mem = __asan_get_current_allocated_bytes();
+    if (used_mem > kLargeAlloc) {
+      printf("After iteration %d: %zu\n", iter, used_mem);
+      return 1;
+    }
+  }
+  printf("Success after %d iterations\n", kNumIterations);
+  return 0;
+}