Android NDK 内存泄露检测

 Andorid中Java层代码内存泄露可以借助leakcanary进行检测；

C++上的内存泄露检测库LeakTracer，于是再找了下，找到了Android上的移植版。

首先建立一个项目，在根目录下建立thirdparty目录，进入该目录，

clone相关库代码:

git clone [email protected]:lizhangqu/LeakTracer.git

在项目src/main/cpp下建立CMakeLists.txt，内容如下

project(Test)
cmake_minimum_required (VERSION 3.6)
include_directories(
${PROJECT_SOURCE_DIR}/include/
${PROJECT_SOURCE_DIR}/../../../../thirdparty/LeakTracer/libleaktracer/include/
)
set(LEAKTRACER_SOURCES
${PROJECT_SOURCE_DIR}/../../../../thirdparty/LeakTracer/libleaktracer/src/AllocationHandlers.cpp
#${PROJECT_SOURCE_DIR}/../../../../thirdparty/LeakTracer/libleaktracer/src/LeakTracerC.c
#检测c代码时打开此注释，否则不要打开
${PROJECT_SOURCE_DIR}/../../../../thirdparty/LeakTracer/libleaktracer/src/MemoryTrace.cpp
)
add_library(leaktracer STATIC ${LEAKTRACER_SOURCES})
set(TEST_FILES
${CMAKE_SOURCE_DIR}/native.cpp
)
add_library(
test-jni
SHARED
${TEST_FILES})
target_link_libraries(
test-jni
leaktracer
log
)

建立src/main/cpp/include/native.h和src/main/cpp/native.cpp文件

native.h

//

// Created by 李樟取 on 2017/6/4.

//

#ifndef TEST_H

#define TEST_H

#include "jni.h"

#ifndef NELEM

# define NELEM(x) ((int) (sizeof(x) / sizeof((x)[0])))

#endif

#ifndef CLASSNAME

#define CLASSNAME "io/github/lizhangqu/test/Test"

#endif

#ifdef ANDROID

#include <android/log.h>

#define TAG "Test"

#define ALOGE(fmt, ...) __android_log_print(ANDROID_LOG_ERROR, TAG, fmt, ##__VA_ARGS__)

#define ALOGI(fmt, ...) __android_log_print(ANDROID_LOG_INFO, TAG, fmt, ##__VA_ARGS__)

#define ALOGD(fmt, ...) __android_log_print(ANDROID_LOG_DEBUG, TAG, fmt, ##__VA_ARGS__)

#define ALOGW(fmt, ...) __android_log_print(ANDROID_LOG_WARN, TAG, fmt, ##__VA_ARGS__)

#else

#define ALOGE printf

#define ALOGI printf

#define ALOGD printf

#define ALOGW printf

#endif

#endif //TEST_H

native.cpp

#include "native.h"
#include "MemoryTrace.hpp"
#include <fstream>
void test(JNIEnv *env, jobject thiz) {
}
static const JNINativeMethod sMethods[] = {
{
const_cast<char *>("test"),
const_cast<char *>("()V"),
reinterpret_cast<void *>(test)
},
};
int registerNativeMethods(JNIEnv *env, const char *className, const JNINativeMethod *methods,
const int numMethods) {
jclass clazz = env->FindClass(className);
if (!clazz) {
ALOGE("Native registration unable to find class '%s'\n", className);
return JNI_FALSE;
}
if (env->RegisterNatives(clazz, methods, numMethods) != 0) {
ALOGE("RegisterNatives failed for '%s'\n", className);
env->DeleteLocalRef(clazz);
return JNI_FALSE;
}
env->DeleteLocalRef(clazz);
return JNI_TRUE;
}
jint JNI_OnLoad(JavaVM *vm, void *reserved) {
JNIEnv *env;
if (vm->GetEnv(reinterpret_cast<void **>(&env), JNI_VERSION_1_6) != JNI_OK) {
return -1;
}
registerNativeMethods(env, CLASSNAME, sMethods, NELEM(sMethods));
return JNI_VERSION_1_6;
}

编写test函数，简单进行内测泄露检测

class MemoryTest {
};
void test(JNIEnv *env, jobject thiz) {
    leaktracer::MemoryTrace::GetInstance().startMonitoringAllThreads();
    MemoryTest *memoryTest = new MemoryTest;
    leaktracer::MemoryTrace::GetInstance().stopAllMonitoring();
    std::ofstream out;
    out.open("/sdcard/leaks.out", std::ios_base::out);
    if (out.is_open()) {
        leaktracer::MemoryTrace::GetInstance().writeLeaks(out);
    } else {
        ALOGE("Failed to write to \"leaks.out\"\n");
    }
}

运行程序后调用test函数，将/sdcard/leaks.out pull到项目根目录

adb pull /sdcard/leaks.out

其内容类似如下内容：

# LeakTracer report diff_utc_mono=1496511718.682943

leak, time=135120.534718, stack=0x36fd6 0x35a90 0x359a4 0x32fea 0xc952d3d0, size=1, data=�

借助thirdparty/LeakTracer/helper/leak-analyze-addr2line工具还原内测泄露堆栈。

进入项目根目录，执行leak-analyze-addr2line

./thirdparty/LeakTracer/helpers/leak-analyze-addr2line ./library/build/intermediates/cmake/debug/obj/armeabi/libtest-jni.so ./leaks.out

在mac上，会出现一个错误，原因是leak-analyze-addr2line中用到了addr2line工具，而mac上如果没有此工具，就会报错，错误如下：

解决方法很简单，将ndk目录中的arm-linux-androideabi-addr2line拷到./thirdparty/LeakTracer/helpers/下，并重命名为addr2line，然后将./thirdparty/LeakTracer/helpers/加到环境变量中，如下代码

cp $ANDROID_NDK_HOME/toolchains/arm-linux-androideabi-4.9/prebuilt/darwin-x86_64/bin/arm-linux-androideabi-addr2line ./thirdparty/LeakTracer/helpers/addr2line

export PATH=$PATH:`pwd`/thirdparty/LeakTracer/helpers

$ANDROID_NDK_HOME表示ndk的根目录。

之后再次调用命令

./thirdparty/LeakTracer/helpers/leak-analyze-addr2line ./library/build/intermediates/cmake/debug/obj/armeabi/libtest-jni.so ./leaks.out

这时候输出如下

native.cpp:15行出现泄露，找到15行对应的代码，即如下代码出现泄露

MemoryTest *memoryTest = new MemoryTest;

加入delete代码，再跑一次

MemoryTest *memoryTest = new MemoryTest;

delete memoryTest;

输出如下

发现之前的泄露不见了

最后，值得注意的是，要想使用LeakTracer需要保留so足够多的debug信息，否则可能不能正常检测。项目Demo地址见

 
 

https://github.com/lizhangqu/NDKMemoryLeakSample