[Android] Introduce libheap_profiler for memory profiling.

tools/android/heap_profiler/heap_profiler_integrationtest.cc

+// Copyright 2014 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include <dlfcn.h>
+#include <fcntl.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/mman.h>
+#include <unistd.h>
+#include <map>
+
+#include "testing/gtest/include/gtest/gtest.h"
+#include "tools/android/heap_profiler/heap_profiler.h"
+
+
+namespace {
+
+// The purpose of the four functions below is to create watermarked allocations,
+// so the test fixture can ascertain that the hooks work end-to-end.
+__attribute__ ((noinline)) void* MallocStep2(size_t size) {

[bulach, 2014/06/24 10:45:14]

nit: maybe format like:
__attribute__ ((noinline))\n
void* MallocStep2(size_t size) {


also...StepN doesn't seem too informative.. how about MallocInner / MallocOuter,
or something?

[Primiano Tucci (use gerrit), 2014/06/24 15:10:57]

Like it. Done

+  void* ptr = malloc(size);
+  // The memset below is to avoid tail-call elimination optimizations and ensure
+  // that this function will be part of the stack trace.
+  memset(ptr, 0, size);
+  return ptr;
+}
+
+__attribute__ ((noinline)) void* MallocStep1(size_t size) {
+  void* ptr = MallocStep2(size);
+  memset(ptr, 0, size);
+  return ptr;
+}
+
+__attribute__ ((noinline)) void* DoMmap(size_t size) {
+  return mmap(
+      0, size, PROT_READ | PROT_WRITE, MAP_PRIVATE | MAP_ANONYMOUS, 0, 0);
+}
+
+__attribute__ ((noinline)) void* MmapStep2(size_t size) {

[bulach, 2014/06/24 10:45:14]

ditto for the N, maybe MmapInner, MmapOuter

[Primiano Tucci (use gerrit), 2014/06/24 15:10:57]

Done.

+  void* ptr = DoMmap(size);
+  memset(ptr, 0, size);
+  return ptr;
+}
+
+__attribute__ ((noinline)) void* MmapStep1(size_t size) {
+  void* ptr = MmapStep2(size);
+  memset(ptr, 0, size);
+  return ptr;
+}
+
+bool StackTraceContains(const uintptr_t* frames, uintptr_t fn_addr) {
+  // expected_fn_length is a gross estimation of the size of the Step* functions
+  // above. It tries to address the following problem: the addrs in the unwound
+  // stack frames will NOT point to the beginning of the functions, but to the
+  // PC after the call to malloc/mmap.
+  const size_t expected_fn_length = 16;

[bulach, 2014/06/24 10:45:13]

nit: kExpectedFnLength
...no idea how easy would it be, but maybe have some inlined asm with N noops?

[Primiano Tucci (use gerrit), 2014/06/24 15:10:57]

Yeah, I thought about that, but unfortunately couldn't come with a portable way
of adding nops :/ (also inline asm would make this entire thing even more gross)
And unfortunately the GCC aligned attribute doesn't apply to functions.

+
+  for(size_t i = 0; i < HEAP_PROFILER_MAX_DEPTH; ++i) {

[bulach, 2014/06/24 10:45:14]

nit: space after for

[Primiano Tucci (use gerrit), 2014/06/24 15:10:56]

Done.

+    if (frames[i] >= fn_addr && frames[i] <= fn_addr + expected_fn_length)
+      return true;
+  }
+  return false;
+}
+
+const HeapStats* GetHeapProfilerStats() {
+  HeapStats* const* stats_ptr = reinterpret_cast<HeapStats* const*>(
+      dlsym(RTLD_DEFAULT, "heap_profiler_stats_for_tests"));
+  EXPECT_TRUE(stats_ptr != NULL);
+  const HeapStats* stats = *stats_ptr;
+  EXPECT_TRUE(stats != NULL);
+  EXPECT_EQ(HEAP_PROFILER_MAGIC_MARKER, stats->magic_start);
+  return stats;
+}
+
+TEST(HeapProfilerIntegrationTest, TestMallocStackTraces) {
+  const HeapStats* stats = GetHeapProfilerStats();
+
+  void* m1 = MallocStep1(1000000);

[bulach, 2014/06/24 10:45:14]

nit: maybe these numbers could be kSizeSmall / Medium / Large?

[Primiano Tucci (use gerrit), 2014/06/24 15:10:57]

Going for kSize1/2/3: their sense is not really be small/large, just be
different.

+  void* m2 = MallocStep2(2000000);
+  void* m3 = MallocStep2(4000000);
+
+  bool m1_found = false;
+  bool m2_found = false;
+  bool m3_found = false;
+
+  ASSERT_TRUE(stats->stack_traces != NULL);
+
+  free(m3);
+
+  for(size_t i = 0; i < stats->max_stack_traces; ++i) {

[bulach, 2014/06/24 10:45:14]

nit: space after for

[Primiano Tucci (use gerrit), 2014/06/24 15:10:57]

Done.

+    const StacktraceEntry* st = &stats->stack_traces[i];
+    if (st->alloc_bytes == 1000000) {
+      m1_found = true;
+      EXPECT_TRUE(StackTraceContains(
+          st->frames, reinterpret_cast<uintptr_t>(&MallocStep1)));
+      EXPECT_TRUE(StackTraceContains(
+          st->frames, reinterpret_cast<uintptr_t>(&MallocStep2)));
+    }
+    else if (st->alloc_bytes == 2000000) {
+      m2_found = true;
+      EXPECT_FALSE(StackTraceContains(
+          st->frames, reinterpret_cast<uintptr_t>(&MallocStep1)));
+      EXPECT_TRUE(StackTraceContains(
+          st->frames, reinterpret_cast<uintptr_t>(&MallocStep2)));
+    }
+    else if (st->alloc_bytes == 4000000) {
+      m3_found = true;
+    }
+  }
+
+  EXPECT_TRUE(m1_found);
+  EXPECT_TRUE(m2_found);
+  EXPECT_FALSE(m3_found);
+
+  const size_t total_alloc_start = stats->total_alloc_bytes;
+  free(m1);
+  free(m2);
+  const size_t total_alloc_end = stats->total_alloc_bytes;
+
+  EXPECT_EQ(3000000, total_alloc_start - total_alloc_end);

[bulach, 2014/06/24 10:45:14]

nit: perhaps kSizeLarge - kSizeSmall..

also, for completeness, perhaps ensure that stats->stack_traces is empty or that
none of the steps above are not found?

[Primiano Tucci (use gerrit), 2014/06/24 15:10:57]

Well, I can check for the delta, they will never be empty. The test harness
itself creates some allocations :)
Done

+}
+
+TEST(HeapProfilerIntegrationTest, TestMmapStackTraces) {

[bulach, 2014/06/24 10:45:13]

this and the previous test is almost the same...

perhaps could have a helper function that takes three function pointers for the
allocators, three sizes and one for the free/munmap?

[Primiano Tucci (use gerrit), 2014/06/24 15:10:57]

Hmm I did some cleanup + factored the LookupStackTraceBySize function.
Extreme factoring of the entire test function seems a bit odd (also I'd split
that in two parts at least, one for before-free, one for the after free).
Is it OK now?

+  const HeapStats* stats = GetHeapProfilerStats();
+
+  static const size_t m1_size = 499 * PAGE_SIZE;
+  static const size_t m2_size = 503 * PAGE_SIZE;
+  static const size_t m3_size = 509 * PAGE_SIZE;

[bulach, 2014/06/24 10:45:13]

nit: kMMapSizeN

[Primiano Tucci (use gerrit), 2014/06/24 15:10:57]

Done.

+
+  void* m1 = MmapStep1(m1_size);
+  void* m2 = MmapStep2(m2_size);
+  void* m3 = MmapStep2(m3_size);
+
+  bool m1_found = false;
+  bool m2_found = false;
+  bool m3_found = false;
+
+  ASSERT_TRUE(stats->stack_traces != NULL);
+
+  munmap(m3, m3_size);
+
+  for(size_t i = 0; i < stats->max_stack_traces; ++i) {

[bulach, 2014/06/24 10:45:13]

nit: space after for

+    const StacktraceEntry* st = &stats->stack_traces[i];
+    if (st->alloc_bytes == m1_size) {
+      m1_found = true;
+      EXPECT_TRUE(StackTraceContains(
+          st->frames, reinterpret_cast<uintptr_t>(&MmapStep1)));
+      EXPECT_TRUE(StackTraceContains(
+          st->frames, reinterpret_cast<uintptr_t>(&MmapStep2)));
+    }
+    else if (st->alloc_bytes == m2_size) {

[bulach, 2014/06/24 10:45:13]

nit: previous line

+      m2_found = true;
+      EXPECT_FALSE(StackTraceContains(
+          st->frames, reinterpret_cast<uintptr_t>(&MmapStep1)));
+      EXPECT_TRUE(StackTraceContains(
+          st->frames, reinterpret_cast<uintptr_t>(&MmapStep2)));
+    }
+    else if (st->alloc_bytes == m3_size) {

[bulach, 2014/06/24 10:45:14]

nit: previous line

+      m3_found = true;
+    }
+  }
+
+  EXPECT_TRUE(m1_found);
+  EXPECT_TRUE(m2_found);
+  EXPECT_FALSE(m3_found);
+
+  const size_t total_alloc_start = stats->total_alloc_bytes;
+  munmap(m1, m1_size);
+  munmap(m2, m2_size);
+  const size_t total_alloc_end = stats->total_alloc_bytes;
+
+  EXPECT_EQ(m1_size + m2_size, total_alloc_start - total_alloc_end);
+}
+
+// Returns the path of the directory containing the current executable.
+std::string GetExePath() {
+  char buf[1024];
+  ssize_t len = readlink("/proc/self/exe", buf, sizeof(buf) - 1);
+  if (len == -1)
+    return std::string();
+  std::string path(buf, len);
+  size_t sep = path.find_last_of('/');
+  if (sep == std::string::npos)
+    return std::string();
+  path.erase(sep);
+  return path;
+}
+
+}  // namespace
+
+
+int main(int argc, char** argv) {
+  // Re-launch the process itself forcing the preload of the libheap_profiler.
+  if (getenv("LD_PRELOAD") == NULL) {
+    char env_ld_lib_path[256];
+    strlcpy(env_ld_lib_path, "LD_LIBRARY_PATH=", sizeof(env_ld_lib_path));
+    strlcat(env_ld_lib_path, GetExePath().c_str(), sizeof(env_ld_lib_path));
+    char env_ld_preload[] = "LD_PRELOAD=libheap_profiler.so";
+    char* const env[] = {env_ld_preload, env_ld_lib_path, 0};
+    execve("/proc/self/exe", argv, env);
+    // execve() never returns, unless something goes wrong.
+    perror("execve");
+    assert(false);
+  }
+
+  testing::InitGoogleTest(&argc, argv);
+  return RUN_ALL_TESTS();
+}