[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 "base/compiler_specific.h"
+#include "testing/gtest/include/gtest/gtest.h"
+#include "tools/android/heap_profiler/heap_profiler.h"
+
+namespace {
+
+typedef void* (*AllocatorFn)(size_t);
+typedef int (*FreeFn)(void*, size_t);
+
+const size_t kSize1 = 499 * PAGE_SIZE;
+const size_t kSize2 = 503 * PAGE_SIZE;
+const size_t kSize3 = 509 * PAGE_SIZE;
+
+// 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* MallocInner(size_t size) {
+  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* MallocOuter(size_t size) {
+  void* ptr = MallocInner(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* MmapInner(size_t size) {
+  void* ptr = DoMmap(size);
+  memset(ptr, 0, size);
+  return ptr;
+}
+
+__attribute__((noinline)) void* MmapOuter(size_t size) {
+  void* ptr = MmapInner(size);
+  memset(ptr, 0, size);
+  return ptr;
+}
+
+const HeapStats* GetHeapStats() {
+  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;
+}
+
+bool StackTraceContains(const StacktraceEntry* s, AllocatorFn fn) {
+  // kExpectedFnLen is a gross estimation of the watermark functions' size.
+  // It tries to address the following problem: the addrs in the unwound stack
+  // stack frames will NOT point to the beginning of the functions, but to the
+  // PC after the call to malloc/mmap.
+  const size_t kExpectedFnLen = 16;
+  const uintptr_t fn_addr = reinterpret_cast<uintptr_t>(fn);
+  for (size_t i = 0; i < HEAP_PROFILER_MAX_DEPTH; ++i) {
+    if (s->frames[i] >= fn_addr && s->frames[i] <= fn_addr + kExpectedFnLen)
+      return true;
+  }
+  return false;
+}
+
+const StacktraceEntry* LookupStackTrace(size_t size, AllocatorFn fn) {
+  const HeapStats* stats = GetHeapStats();
+  for (size_t i = 0; i < stats->max_stack_traces; ++i) {
+    const StacktraceEntry* st = &stats->stack_traces[i];
+    if (st->alloc_bytes == size && StackTraceContains(st, fn))
+      return st;
+  }
+  return NULL;
+}
+
+int DoFree(void* addr, size_t /*size, ignored.*/) {
+  free(addr);
+  return 0;
+}
+
+void TestStackTracesWithParams(AllocatorFn outer_fn,
+                               AllocatorFn inner_fn,
+                               FreeFn free_fn) {
+  const HeapStats* stats = GetHeapStats();
+
+  void* m1 = outer_fn(kSize1);
+  void* m2 = inner_fn(kSize2);
+  void* m3 = inner_fn(kSize3);
+  free_fn(m3, kSize3);
+
+  const StacktraceEntry* st1 = LookupStackTrace(kSize1, inner_fn);
+  const StacktraceEntry* st2 = LookupStackTrace(kSize2, inner_fn);
+  const StacktraceEntry* st3 = LookupStackTrace(kSize3, inner_fn);
+
+  EXPECT_TRUE(st1 != NULL);
+  EXPECT_TRUE(StackTraceContains(st1, outer_fn));
+  EXPECT_TRUE(StackTraceContains(st1, inner_fn));
+
+  EXPECT_TRUE(st2 != NULL);
+  EXPECT_FALSE(StackTraceContains(st2, outer_fn));
+  EXPECT_TRUE(StackTraceContains(st2, inner_fn));
+
+  EXPECT_EQ(NULL, st3);
+
+  const size_t total_alloc_start = stats->total_alloc_bytes;
+  const size_t num_stack_traces_start = stats->num_stack_traces;
+
+  free_fn(m1, kSize1);
+  free_fn(m2, kSize2);
+
+  const size_t total_alloc_end = stats->total_alloc_bytes;
+  const size_t num_stack_traces_end = stats->num_stack_traces;
+
+  EXPECT_EQ(kSize1 + kSize2, total_alloc_start - total_alloc_end);
+  EXPECT_EQ(2, num_stack_traces_start - num_stack_traces_end);
+  EXPECT_EQ(NULL, LookupStackTrace(kSize1, inner_fn));
+  EXPECT_EQ(NULL, LookupStackTrace(kSize2, inner_fn));
+  EXPECT_EQ(NULL, LookupStackTrace(kSize3, inner_fn));
+}
+
+TEST(HeapProfilerIntegrationTest, TestMallocStackTraces) {
+  TestStackTracesWithParams(&MallocOuter, &MallocInner, &DoFree);
+}
+
+TEST(HeapProfilerIntegrationTest, TestMmapStackTraces) {
+  TestStackTracesWithParams(&MmapOuter, &MmapInner, &munmap);
+}
+
+// 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.
+  char* ld_preload = getenv("LD_PRELOAD");
+  if (ld_preload == NULL || strstr(ld_preload, "libheap_profiler.so") == 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();
+}