platform_system_core/libbacktrace/UnwindMap.cpp
Christopher Ferris 086baf981d Switch libbacktrace new unwinder.
Update the backtrace leak tests to share a map since this is the most
common way it will be used, and it runs much faster.

Remove the CreateNew functions, and references to them.

Remove benchmarks of CreateNew functions.

Test: Builds, ran new unit tests, ran art tests.

Change-Id: I4a25a412f1a74c6d43aebbebbf32ead20ead8f94
2017-10-30 13:37:50 -07:00

148 lines
4.2 KiB
C++

/*
* Copyright (C) 2014 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#include <pthread.h>
#include <stdint.h>
#include <stdlib.h>
#include <sys/types.h>
#include <unistd.h>
#include <backtrace/BacktraceMap.h>
#include <libunwind.h>
#include "BacktraceLog.h"
#include "UnwindMap.h"
//-------------------------------------------------------------------------
// libunwind has a single shared address space for the current process
// aka local. If multiple maps are created for the current pid, then
// only update the local address space once, and keep a reference count
// of maps using the same map cursor.
//-------------------------------------------------------------------------
UnwindMap::UnwindMap(pid_t pid) : BacktraceMap(pid) {
unw_map_cursor_clear(&map_cursor_);
}
UnwindMapRemote::UnwindMapRemote(pid_t pid) : UnwindMap(pid) {
}
UnwindMapRemote::~UnwindMapRemote() {
unw_map_cursor_destroy(&map_cursor_);
unw_map_cursor_clear(&map_cursor_);
}
bool UnwindMapRemote::GenerateMap() {
// Use the map_cursor information to construct the BacktraceMap data
// rather than reparsing /proc/self/maps.
unw_map_cursor_reset(&map_cursor_);
unw_map_t unw_map;
while (unw_map_cursor_get_next(&map_cursor_, &unw_map)) {
backtrace_map_t map;
map.start = unw_map.start;
map.end = unw_map.end;
map.offset = unw_map.offset;
map.load_bias = unw_map.load_base;
map.flags = unw_map.flags;
map.name = unw_map.path;
// The maps are in descending order, but we want them in ascending order.
maps_.push_front(map);
}
return true;
}
bool UnwindMapRemote::Build() {
return (unw_map_cursor_create(&map_cursor_, pid_) == 0) && GenerateMap();
}
UnwindMapLocal::UnwindMapLocal() : UnwindMap(getpid()), map_created_(false) {
pthread_rwlock_init(&map_lock_, nullptr);
}
UnwindMapLocal::~UnwindMapLocal() {
if (map_created_) {
unw_map_local_destroy();
unw_map_cursor_clear(&map_cursor_);
}
}
bool UnwindMapLocal::GenerateMap() {
// Lock so that multiple threads cannot modify the maps data at the
// same time.
pthread_rwlock_wrlock(&map_lock_);
// It's possible for the map to be regenerated while this loop is occurring.
// If that happens, get the map again, but only try at most three times
// before giving up.
bool generated = false;
for (int i = 0; i < 3; i++) {
maps_.clear();
// Save the map data retrieved so we can tell if it changes.
unw_map_local_cursor_get(&map_cursor_);
unw_map_t unw_map;
int ret;
while ((ret = unw_map_local_cursor_get_next(&map_cursor_, &unw_map)) > 0) {
backtrace_map_t map;
map.start = unw_map.start;
map.end = unw_map.end;
map.offset = unw_map.offset;
map.load_bias = unw_map.load_base;
map.flags = unw_map.flags;
map.name = unw_map.path;
free(unw_map.path);
// The maps are in descending order, but we want them in ascending order.
maps_.push_front(map);
}
// Check to see if the map changed while getting the data.
if (ret != -UNW_EINVAL) {
generated = true;
break;
}
}
pthread_rwlock_unlock(&map_lock_);
if (!generated) {
BACK_LOGW("Unable to generate the map.");
}
return generated;
}
bool UnwindMapLocal::Build() {
return (map_created_ = (unw_map_local_create() == 0)) && GenerateMap();;
}
void UnwindMapLocal::FillIn(uintptr_t addr, backtrace_map_t* map) {
BacktraceMap::FillIn(addr, map);
if (!IsValid(*map)) {
// Check to see if the underlying map changed and regenerate the map
// if it did.
if (unw_map_local_cursor_valid(&map_cursor_) < 0) {
if (GenerateMap()) {
BacktraceMap::FillIn(addr, map);
}
}
}
}