How to use NDK-STACK tool to debug Cocos2d-x android project.

cocos2d-x C++
#1

Android NDK-STACK Tool

‘ndk-stack’ is a simple tool that allows you to analyze stack traces as they appear in the output of ‘adb logcat’ and replace any address inside a shared library with the corresponding values.

In the output of ‘adb logcat’, you may see something like the followings, and we must translate those:

I/DEBUG   (   31): *** *** *** *** *** *** *** *** *** *** *** *** *** *** *** ***
I/DEBUG   (   31): Build fingerprint: 'generic/google_sdk/generic/:2.2/FRF91/43546:eng/test-keys'
I/DEBUG   (   31): pid: 351, tid: 351  %gt;%gt;%gt; /data/local/ndk-tests/crasher <<<
I/DEBUG   (   31): signal 11 (SIGSEGV), fault addr 0d9f00d8
I/DEBUG   (   31):  r0 0000af88  r1 0000a008  r2 baadf00d  r3 0d9f00d8
I/DEBUG   (   31):  r4 00000004  r5 0000a008  r6 0000af88  r7 00013c44
I/DEBUG   (   31):  r8 00000000  r9 00000000  10 00000000  fp 00000000
I/DEBUG   (   31):  ip 0000959c  sp be956cc8  lr 00008403  pc 0000841e  cpsr 60000030
I/DEBUG   (   31):          #00  pc 0000841e  /data/local/ndk-tests/crasher
I/DEBUG   (   31):          #01  pc 000083fe  /data/local/ndk-tests/crasher
I/DEBUG   (   31):          #02  pc 000083f6  /data/local/ndk-tests/crasher
I/DEBUG   (   31):          #03  pc 000191ac  /system/lib/libc.so
I/DEBUG   (   31):          #04  pc 000083ea  /data/local/ndk-tests/crasher
I/DEBUG   (   31):          #05  pc 00008458  /data/local/ndk-tests/crasher
I/DEBUG   (   31):          #06  pc 0000d362  /system/lib/libc.so
I/DEBUG   (   31):

How to use this tool

If you succeed in building Cocos2d-x android project, it will generate shared libraries in $PROJECT_PATH/obj/local/ , where stands for your device’s ABI (i.e.‘armeabi’ by default);

You can feed the logcat text either as direct input to the program, e.g.:

adb logcat | $NDK/ndk-stack -sym $PROJECT_PATH/obj/local/armeabi

Or you can use the -dump option to specify the logcat as an input file, e.g.:

adb logcat > /tmp/foo.txt
$NDK/ndk-stack -sym $PROJECT_PATH/obj/local/armeabi -dump foo.txt

After that, you will get the more readable output:

********** Crash dump: **********
Build fingerprint: 'generic/google_sdk/generic/:2.2/FRF91/43546:eng/test-keys'
pid: 351, tid: 351  >>> /data/local/ndk-tests/crasher <<<
signal 11 (SIGSEGV), fault addr 0d9f00d8
Stack frame #00  pc 0000841e  /data/local/ndk-tests/crasher : Routine zoo in /tmp/foo/crasher/jni/zoo.c:13
Stack frame #01  pc 000083fe  /data/local/ndk-tests/crasher : Routine bar in /tmp/foo/crasher/jni/bar.c:5
Stack frame #02  pc 000083f6  /data/local/ndk-tests/crasher : Routine my_comparison in /tmp/foo/crasher/jni/foo.c:9
Stack frame #03  pc 000191ac  /system/lib/libc.so
Stack frame #04  pc 000083ea  /data/local/ndk-tests/crasher : Routine foo in /tmp/foo/crasher/jni/foo.c:14
Stack frame #05  pc 00008458  /data/local/ndk-tests/crasher : Routine main in /tmp/foo/crasher/jni/main.c:19
Stack frame #06  pc 0000d362  /system/lib/libc.so

IMPORTANT

The tool looks for the initial line containing starts in the logcat output, i.e.something this looks like:

*** *** *** *** *** *** *** *** *** *** *** *** *** *** *** ***

When copy/pasting traces, don’t forget this line from the traces, or ndk-stack won’t work correctly.

Now both the versions(linux/windows/mac) of ndk-stack are available at Android Developer .

References

$NDK_ROOT/docs/NDK-STACK.html

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#2

Amazing! Thanks a lot!~

#3

Here’s the format of the command I use today, in case anyone else runs into the same problem, I had to make sure I pointed at the symbol directory, and that I used the correct ndk version.

E:\Cocos\tools\android-ndk-r10c\ndk-stack.exe -sym PROJECTNAME\proj.android\obj\local\armeabi-v7a\  -dump PROJECTNAME\trace.log > PROJECTNAME\output.log
#4

Hi,
I don’t have the folder \obj\local… in my project path (proj.android).
I’m using Android Studio 3.1.3 for Mac and NDK 16.
How to solve it?

#5

Could be a new version of android or something changing up the folder layouts but I’m surprised. Maybe it’s somewhere else? Make sure the game compiles too, otherwise it wouldn’t exist.

#6

Yes, the game compiles fine. But i don’t find the folder, haha.
Are you using the same versions that I described before?

#7

I found this folders:

../proj.android//app/build/intermediates/ndkBuild/release/obj/local/armeabi-v7a
../proj.android//app/build/intermediates/ndkBuild/debug/obj/local/armeabi-v7a

Maybe I should test with the second.
EDIT: Yes, that’s the folder.

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