[asan] first attempt at releasing free-d memory back to the system using madvise. Requires quite some tuning.

git-svn-id: https://llvm.org/svn/llvm-project/compiler-rt/trunk@279887 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 45 insertions, 0 deletions

diff --git a/test/asan/TestCases/Linux/release_to_os_test.cc b/test/asan/TestCases/Linux/release_to_os_test.cc
new file mode 100644
index 000000000..c461d034f
--- /dev/null
+++ b/test/asan/TestCases/Linux/release_to_os_test.cc
@@ -0,0 +1,45 @@
+// Tests ASAN_OPTIONS=allocator_release_to_os=1
+//
+
+// RUN: %clangxx_asan -std=c++11 %s -o %t
+// RUN: %env_asan_opts=allocator_release_to_os=1 %run %t 2>&1 | FileCheck %s --check-prefix=RELEASE
+// RUN: %env_asan_opts=allocator_release_to_os=0 %run %t 2>&1 | FileCheck %s --check-prefix=NO_RELEASE
+//
+// REQUIRES: asan-64-bits
+#include <stdio.h>
+#include <algorithm>
+#include <stdint.h>
+#include <assert.h>
+
+#include <sanitizer/asan_interface.h>
+
+void MallocReleaseStress() {
+  const size_t kNumChunks = 10000;
+  const size_t kAllocSize = 100;
+  const size_t kNumIter = 100;
+  uintptr_t *chunks[kNumChunks] = {0};
+
+  for (size_t iter = 0; iter < kNumIter; iter++) {
+    std::random_shuffle(chunks, chunks + kNumChunks);
+    size_t to_replace = rand() % kNumChunks;
+    for (size_t i = 0; i < kNumChunks; i++) {
+      if (chunks[i])
+        assert(chunks[i][0] == (uintptr_t)chunks[i]);
+      if (i < to_replace) {
+        delete [] chunks[i];
+        chunks[i] = new uintptr_t[kAllocSize];
+        chunks[i][0] = (uintptr_t)chunks[i];
+      }
+    }
+  }
+  for (auto p : chunks)
+    delete[] p;
+}
+
+int main() {
+  MallocReleaseStress();
+  __asan_print_accumulated_stats();
+}
+
+// RELEASE: mapped:{{.*}}releases: {{[1-9]}}
+// NO_RELEASE: mapped:{{.*}}releases: 0