[Android] Introduce libheap_profiler for memory profiling.

tools/android/heap_profiler/heap_profiler_hooks_android.c

Index: tools/android/heap_profiler/heap_profiler_hooks_android.c
diff --git a/tools/android/heap_profiler/heap_profiler_hooks_android.c b/tools/android/heap_profiler/heap_profiler_hooks_android.c
new file mode 100644
index 0000000000000000000000000000000000000000..baa536da207b80e1627154046135c0865e67a6a0
--- /dev/null
+++ b/tools/android/heap_profiler/heap_profiler_hooks_android.c
@@ -0,0 +1,210 @@
+// Copyright 2014 The Chromium Authors. All rights reserved.

[pasko, 2014/06/23 20:09:23]

why does the file name contain "android"? wouldn't most of it work on Linux?

[Primiano Tucci (use gerrit), 2014/06/24 08:43:33]

In theory most of it should work on Linux. In practice I haven't tested it and
there are some small nitty gritty header diffs w.r.t. Android as the one you
found in mremap.

This is the long term plan to be honest. But until I haven't tested this on
Linux, I don't want to lie and cause headaches to somebody else who might get
intrigued by the name.
Forthe future I was thinking in renaming this into heap_profiler_hooks_posix.cc
and specializing the diff functions in ..._android and ..._linux.

+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include <dlfcn.h>
+#include <errno.h>
+#include <fcntl.h>
+#include <stdbool.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/mman.h>
+#include <unistd.h>
+#include <unwind.h>
+
+#include "tools/android/heap_profiler/heap_profiler.h"
+
+#define HEAP_PROFILER_EXPORT __attribute__((visibility("default")))
+
+
+static inline __attribute__((always_inline))
+uint32_t get_backtrace(uintptr_t* frames, uint32_t max_depth);
+
+// Function pointers typedefs for the hooked symbols.
+typedef void* (*mmap_t)(void*, size_t, int, int, int, off_t);
+typedef void* (*mmap2_t)(void*, size_t, int, int, int, off_t);
+typedef void* (*mmap64_t)(void*, size_t, int, int, int, off64_t);
+typedef void* (*mremap_t)(void*, size_t, size_t, unsigned long);
+typedef int (*munmap_t)(void*, size_t);
+typedef void* (*malloc_t)(size_t);
+typedef void* (*calloc_t)(size_t, size_t);
+typedef void* (*realloc_t)(void*, size_t);
+typedef void (*free_t)(void*);
+
+// And their actual definitions.
+static mmap_t real_mmap;
+static mmap2_t real_mmap2;
+static mmap64_t real_mmap64;
+static mremap_t real_mremap;
+static munmap_t real_munmap;
+static malloc_t real_malloc;
+static calloc_t real_calloc;
+static realloc_t real_realloc;
+static free_t real_free;
+static int* has_forked_off_zygote;
+
+HEAP_PROFILER_EXPORT const HeapStats* heap_profiler_stats_for_tests;
+
+// +---------------------------------------------------------------------------+
+// + Initialization of heap_profiler and lookup of hooks' addresses            +
+// +---------------------------------------------------------------------------+
+__attribute__((constructor))
+static void initialize() {
+  real_mmap = (mmap_t) dlsym(RTLD_NEXT, "mmap");
+  real_mmap2 = (mmap_t) dlsym(RTLD_NEXT, "mmap2");
+  real_mmap64 = (mmap64_t) dlsym(RTLD_NEXT, "mmap64");
+  real_mremap = (mremap_t) dlsym(RTLD_NEXT, "mremap");
+  real_munmap = (munmap_t) dlsym(RTLD_NEXT, "munmap");
+  real_malloc = (malloc_t) dlsym(RTLD_NEXT, "malloc");
+  real_calloc = (calloc_t) dlsym(RTLD_NEXT, "calloc");
+  real_realloc = (realloc_t) dlsym(RTLD_NEXT, "realloc");
+  real_free = (free_t) dlsym(RTLD_NEXT, "free");
+
+  // gMallocLeakZygoteChild is an extra useful piece of information to have.
+  // When available, it tells whether we're in the zygote (=0) or forked (=1)
+  // a child off it. In the worst case it will be NULL and we'll just ignore it.
+  has_forked_off_zygote = (int*) dlsym(RTLD_NEXT, "gMallocLeakZygoteChild");
+
+  // Allocate room for the HeapStats area and initialize the heap profiler.
+  // Make an explicit map of /dev/zero (instead of MAP_ANONYMOUS), so that the
+  // heap_dump tool can easily spot the mapping in the target process.
+  int fd = open("/dev/zero", O_RDONLY);
+  if (fd < 0) {
+    perror("open");
+    abort();  // This world has gone wrong. Good night Vienna.
+  }
+
+  HeapStats* stats = (HeapStats*) real_mmap(
+      0, sizeof(HeapStats), PROT_READ | PROT_WRITE, MAP_PRIVATE, fd, 0);
+  heap_profiler_stats_for_tests = stats;
+  heap_profiler_init(stats);
+}
+
+static inline __attribute__((always_inline)) void unwind_and_record_alloc(
+    void* start, size_t size, uint32_t flags) {
+  const int errno_save = errno;
+  uintptr_t frames[HEAP_PROFILER_MAX_DEPTH];
+  const uint32_t depth = get_backtrace(frames, HEAP_PROFILER_MAX_DEPTH);
+  if (has_forked_off_zygote != NULL && *has_forked_off_zygote == 0)
+    flags |= HEAP_PROFILER_FLAGS_IN_ZYGOTE;
+  heap_profiler_alloc(start, size, frames, depth, flags);
+  errno = errno_save;
+}
+
+static inline __attribute__((always_inline)) void discard_alloc(
+    void* start, size_t size, uint32_t* old_flags) {
+  const int errno_save = errno;
+  heap_profiler_free(start, size, old_flags);
+  errno = errno_save;
+}
+
+// Flags are non-functional extra decorators that are made available to the
+// final heap_dump tool, to get more details about the source of the allocation.
+static uint32_t get_flags_for_mmap(int fd) {
+  return HEAP_PROFILER_FLAGS_MMAP | (fd ? HEAP_PROFILER_FLAGS_MMAP_FILE : 0);
+}
+
+// +---------------------------------------------------------------------------+
+// + Actual mmap/malloc hooks                                                  +
+// +---------------------------------------------------------------------------+
+HEAP_PROFILER_EXPORT void* mmap(
+    void* addr, size_t size, int prot, int flags, int fd, off_t offset)  {
+  void* ret = real_mmap(addr, size, prot, flags, fd, offset);
+  if (ret != MAP_FAILED)
+    unwind_and_record_alloc(ret, size, get_flags_for_mmap(fd));
+  return ret;
+}
+
+HEAP_PROFILER_EXPORT void* mmap2(
+    void* addr, size_t size, int prot, int flags, int fd, off_t pgoffset)  {
+  void* ret = real_mmap2(addr, size, prot, flags, fd, pgoffset);
+  if (ret != MAP_FAILED)
+    unwind_and_record_alloc(ret, size, get_flags_for_mmap(fd));
+  return ret;
+}
+
+HEAP_PROFILER_EXPORT void* mmap64(
+    void* addr, size_t size, int prot, int flags, int fd, off64_t offset) {
+  void* ret = real_mmap64(addr, size, prot, flags, fd, offset);
+  if (ret != MAP_FAILED)
+    unwind_and_record_alloc(ret, size, get_flags_for_mmap(fd));
+  return ret;
+}
+
+HEAP_PROFILER_EXPORT void* mremap(
+    void* addr, size_t oldlen, size_t newlen, unsigned long flags) {
+  void* ret = real_mremap(addr, oldlen, newlen, flags);
+  if (ret != MAP_FAILED) {
+    uint32_t flags = 0;
+    if (addr)
+      discard_alloc(addr, oldlen, &flags);
+    if (newlen > 0)
+      unwind_and_record_alloc(ret, newlen, flags);
+  }
+  return ret;
+}
+
+HEAP_PROFILER_EXPORT int munmap(void* ptr, size_t size) {
+  int ret = real_munmap(ptr, size);
+  discard_alloc(ptr, size, /*old_flags=*/NULL);

[pasko, 2014/06/23 20:09:23]

nit: a single space character after the comment would look 0.01% nicer

[Primiano Tucci (use gerrit), 2014/06/24 08:43:33]

I can't find the reference in the code style anymore (we might have removed it),
but last time I checked I remember that was telling to not put a space there.
A search in codereview seems to agree:
\/\*\w+=\*\/\w     -> 32 results
\/\*\w+=\*\/\s+\w  -> 7 results

+  return ret;
+}
+
+HEAP_PROFILER_EXPORT void* malloc(size_t byte_count) {
+  void* ret = real_malloc(byte_count);
+  if (ret != NULL)
+    unwind_and_record_alloc(ret, byte_count, HEAP_PROFILER_FLAGS_MALLOC);
+  return ret;
+}
+
+HEAP_PROFILER_EXPORT void* calloc(size_t nmemb, size_t size) {
+  void* ret = real_calloc(nmemb, size);
+  if (ret != NULL)
+    unwind_and_record_alloc(ret, nmemb * size, HEAP_PROFILER_FLAGS_MALLOC);
+  return ret;
+}
+
+HEAP_PROFILER_EXPORT void* realloc(void* ptr, size_t size) {
+  void* ret = real_realloc(ptr, size);
+  uint32_t flags = 0;
+  if (ptr)
+    discard_alloc(ptr, 0, &flags);
+  if (ret != NULL)
+    unwind_and_record_alloc(ret, size, flags | HEAP_PROFILER_FLAGS_MALLOC);
+  return ret;
+}
+
+HEAP_PROFILER_EXPORT void free(void* ptr) {
+  real_free(ptr);
+  discard_alloc(ptr, 0, /*old_flags=*/NULL);
+}
+
+// +---------------------------------------------------------------------------+
+// + Stack unwinder                                                            +
+// +---------------------------------------------------------------------------+
+typedef struct {
+  uintptr_t* frames;
+  uint32_t frame_count;
+  uint32_t max_depth;
+  bool have_skipped_self;
+} stack_crawl_state_t;
+
+static _Unwind_Reason_Code unwind_fn(struct _Unwind_Context* ctx, void* arg) {
+  stack_crawl_state_t* state = (stack_crawl_state_t*) arg;
+  uintptr_t ip = _Unwind_GetIP(ctx);
+
+  if (ip != 0 && !state->have_skipped_self) {
+    state->have_skipped_self = true;
+    return _URC_NO_REASON;
+  }
+
+  state->frames[state->frame_count++] = ip;
+  return (state->frame_count >= state->max_depth) ?
+          _URC_END_OF_STACK : _URC_NO_REASON;
+}
+
+static uint32_t get_backtrace(uintptr_t* frames, uint32_t max_depth) {
+  stack_crawl_state_t state = {.frames = frames, .max_depth = max_depth};
+  _Unwind_Backtrace(unwind_fn, &state);
+  return state.frame_count;
+}