[MTK] 如何在android native code 打callstack

2020-10-13

阅读：2042

[DESCRIPTION]

分析native代码流程相关问题时可以用如下方式打出调用栈，适用于Android P及以上

[SOLUTION]

三个步骤

1.找到你需要添加callstack的源代码所在的Android.bp文件

frameworks/av/media/libmedia/Android.bp

2.在Android.bp文件中找到你需要添加callstack的源文件所对应的cc_library name，再在cc_library下面找到"header_libs"和"shared_libs" ，分别添加如下两行代码

在header_libs下面添加"libutils_headers",

在shared_libs下面添加"libutilscallstack",

3.在你需要添加callstack的源文件中引入CallStack的头文件，并在相应代码处添加log即可#include

@@ -378,6 +379,7 @@ status_t MediaPlayer::stop()

status_t MediaPlayer::pause()

{

ALOGV("pause");

+ CallStack stack("pause");

下面以在MediaPlayer.cpp代码的pause()方法和isPlaying()中加callstack为例来做说明，以下内容是git diff文件media/libmedia/Android.bp | 2 ++

media/libmedia/mediaplayer.cpp | 3 +++

2 files changed, 5 insertions(+)

mode change 100644 => 100755 media/libmedia/mediaplayer.cpp

diff --git a/media/libmedia/Android.bp b/media/libmedia/Android.bp

index 1d335901c5..c8230645e3 100644

--- a/media/libmedia/Android.bp

+++ b/media/libmedia/Android.bp

@@ -270,6 +270,7 @@ cc_library {

header_libs: [

"libstagefright_headers",

"media_ndk_headers",

+ "libutils_headers",

],

export_header_lib_headers: [

@@ -283,6 +284,7 @@ cc_library {

"libcutils",

"libprocessgroup",

"libutils",

+ "libutilscallstack",

"libbinder",

"libsonivox",

"libandroidicu",

diff --git a/media/libmedia/mediaplayer.cpp b/media/libmedia/mediaplayer.cpp

old mode 100644

new mode 100755

index 6767bba75b..72d65e9564

--- a/media/libmedia/mediaplayer.cpp

+++ b/media/libmedia/mediaplayer.cpp

@@ -45,6 +45,7 @@

#include

#include

+#include

namespace android {

@@ -378,6 +379,7 @@ status_t MediaPlayer::stop()

status_t MediaPlayer::pause()

{

ALOGV("pause");

+ CallStack stack("pause");

Mutex::Autolock _l(mLock);

if (mCurrentState & (MEDIA_PLAYER_PAUSED|MEDIA_PLAYER_PLAYBACK_COMPLETE))

return NO_ERROR;

@@ -401,6 +403,7 @@ bool MediaPlayer::isPlaying()

bool temp = false;

mPlayer->isPlaying(&temp);

ALOGV("isPlaying: %d", temp);

+ CallStack stack("isPlaying");

if ((mCurrentState & MEDIA_PLAYER_STARTED) && ! temp) {

ALOGE("internal/external state mismatch corrected");

mCurrentState = MEDIA_PLAYER_PAUSED;

--

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