Android：在 android 工作室中进行 NDK-Build C/C++ 调试

Question

Trying ndk-build C code debug in Android studio(v4.1.2).Below is build.gradle setup.

1. jni, C/C++ Source files Dirs. Actual C files are not under jni folder but outside it but referred in android.mk file.

   sourceSets.main.jniLibs.srcDirs = ['D:/ccodefolder/jni/']

2)Android.mk Builds a shared library from C, c++ code and also links inbuilt shared and static libraries.

 externalNativeBuild {
           ndkBuild {
               path file('D:/ccodefolder/jni/Android.mk')
           }
       }
       ndkVersion '21.1.6352462'

debug {
        debuggable true
        jniDebuggable true
        minifyEnabled false
        shrinkResources false
       //ndk.debugSymbolLevel = 'FULL'
    }

4)Project structure is as in the image.

Able to run the project and shared library get generated along with other prebuilt.SOs and apk works, also CPP folder is created and able to see C code files of my project.

DEBUGGING ISSUE:

LLDB server gets started and Debugger attached to process, But debug any C file is failing with below error.

Breakpoint will not currently be hit. No executable code is associated with this line

Thanks

Answer 1

There are a couple things you can try, I've had success with each solution.

From the NDK Bug Tracker :

Select Run -> Edit Configurations

On the left side, select Android App -> app

On the right side, select the Debugger tab

Under the Symbol Directories sub-tab, press the + button

Browse to the following path:

libModule/build/intermediates/cmake/debug/obj In the Build Variants window, select the "debug" configuration for the app

The other solution I've found that sometimes works is to only add breakpoints inside C++ code ONLY. The Android Studio debugger does not handle the transition from Java/Kotlin to C++ well. I have found that by removing all Java breakpoints, restarting Android Studio, and launching debug mode again, the C++ breakpoints will now be hit (though any Java breakpoints now added will be missed).

Answer 2

1. Have you used Proguard before? Check these SO answers , specially the one regarding adding the lines to proguard-rules.pro

2. Also check if you have debug type set to Java Only . For this go to the top bar, in the 'app' selector go to Edit Configurations. Select 'app' then go to Debugger.

3. It can also be because of Instant Run. To disable Instant run go to File > Settings > Build, execution, deployment > Instant run > Uncheck Enable Instant Run

4. Another issue might be Android Studio is in offline mode. To disable Offline mode: File > Settings (Ctrl-Alt-S) > Build, Execution, Deployment > Gradle Under Global gradle settings: Offline work checkbox

5. Last but not least. Have you tried Invalidate Caches/Restart? Go to File -> Invalidate Caches/Restart. This will clean the cache that might be messing up the debugger.

Answer 3

Other answers are useful.

But the real problem for me was in my android.mk file having LOCAL_LDFLAGS --strip-all which didnt generate symbols for debugging. Once it was removed debugging is working.

NDK team comments: https://issuetracker.google.com/issues/179634983

For the .so file(s) built by ndk-build:
Android Studio can automatically identify the location of the debugging symbol files.
Breakpoints should work without any additional effort.
For the .so file(s) that are included as prebuilt libraries using jniLibs.srcDirs:
Android Studio does not know where to find the debugging symbol files.
Breakpoints set on C++ files that were compiled into these .so libraries will show up as Breakpoint will not be hit. No executable code is associated with this line warnings, and won't hit.
You need to tell Android Studio where to find the symbol files for these .so files.
You can achieve this by adding the directory of your symbol files to Edit Configurations... | Debugger | Symbol Directories.