Android NDK和GDB调试

Question

I'm having trouble debugging my native application with GDB (on Windows), please excuse the length of this post. I'm using a standard setup (Eclipse with ADT, ndk-build). My build command is:

ndk-build NDK_DEBUG=1 V=1

and here are my Android.mk and Application.mk files:

Android.mk:

LOCAL_PATH := $(call my-dir)

include $(CLEAR_VARS)

FILE_LIST := $(wildcard $(LOCAL_PATH)/../../source/*.cpp)
FILE_LIST += $(wildcard $(LOCAL_PATH)/../../source/android/*.cpp)

LOCAL_MODULE        := RAGEAndroid
LOCAL_SRC_FILES     := $(FILE_LIST:$(LOCAL_PATH)/%=%)

LOCAL_LDLIBS        := -llog -landroid -lm -lEGL -lGLESv3
LOCAL_STATIC_LIBRARIES := android_native_app_glue

LOCAL_CPPFLAGS      := -std=c++11 -pthread -DRAGE_ANDROID #-ftemplate-backtrace-limit=0
ifeq ($(NDK_DEBUG),1)
    LOCAL_CPPFLAGS      += -DRAGE_DEBUG
endif

include $(BUILD_SHARED_LIBRARY)

$(call import-module,android/native_app_glue)

Application.mk

APP_STL                 := gnustl_static
NDK_TOOLCHAIN_VERSION   := 4.8
APP_ABI                 := armeabi-v7a
APP_PLATFORM            := android-18

Verbose mode outputs the following during build (just showing the build of a single file for now, please note I only showed one .o file being linked and omitted the rest for easy reading with the tag #OMITTED OTHER .O FILES#):

"E:\\Development\\Toolchains\\android-ndk-r9c\\ndk-build.cmd" NDK_DEBUG=1 V=1 all 
del /f/q .\libs\armeabi-v7a\libRAGEAndroid.so   >NUL 2>NUL
del /f/q .\libs\armeabi-v7a\gdbserver   >NUL 2>NUL
del /f/q .\libs\armeabi-v7a\gdb.setup   >NUL 2>NUL
[armeabi-v7a] Gdbserver      : [arm-linux-androideabi-4.8] libs/armeabi-v7a/gdbserver
copy /b/y "E:\Development\Toolchains\android-ndk-r9c\prebuilt\android-arm\gdbserver\gdbserver" ".\libs\armeabi-v7a\gdbserver" > NUL
[armeabi-v7a] Gdbsetup       : libs/armeabi-v7a/gdb.setup
E:/Development/Toolchains/android-ndk-r9c/prebuilt/windows-x86_64/bin/echo.exe "set solib-search-path ./obj/local/armeabi-v7a" > ./libs/armeabi-v7a/gdb.setup
E:/Development/Toolchains/android-ndk-r9c/prebuilt/windows-x86_64/bin/echo.exe "directory E:/Development/Toolchains/android-ndk-r9c/platforms/android-18/arch-arm/usr/include E:/Development/Toolchains/android-ndk-r9c/sources/android/native_app_glue E:/Development/Toolchains/android-ndk-r9c/sources/cxx-stl/gnu-libstdc++/4.8/include E:/Development/Toolchains/android-ndk-r9c/sources/cxx-stl/gnu-libstdc++/4.8/libs/armeabi-v7a/include E:/Development/Toolchains/android-ndk-r9c/sources/cxx-stl/gnu-libstdc++/4.8/include/backward jni" >> ./libs/armeabi-v7a/gdb.setup
[armeabi-v7a] Compile++ thumb: RAGEAndroid <= main.cpp
E:/Development/Toolchains/android-ndk-r9c/toolchains/arm-linux-androideabi-4.8/prebuilt/windows-x86_64/bin/arm-linux-androideabi-g++ -MMD -MP -MF ./obj/local/armeabi-v7a/objs-debug/RAGEAndroid/__/__/source/android/main.o.d -fpic -ffunction-sections -funwind-tables -fstack-protector -no-canonical-prefixes -march=armv7-a -mfloat-abi=softfp -mfpu=vfpv3-d16 -fno-exceptions -fno-rtti -mthumb -Os -g -DNDEBUG -fomit-frame-pointer -fno-strict-aliasing -finline-limit=64 -O0 -UNDEBUG -marm -fno-omit-frame-pointer -IE:/Development/Toolchains/android-ndk-r9c/sources/android/native_app_glue -IE:/Development/Toolchains/android-ndk-r9c/sources/cxx-stl/gnu-libstdc++/4.8/include -IE:/Development/Toolchains/android-ndk-r9c/sources/cxx-stl/gnu-libstdc++/4.8/libs/armeabi-v7a/include -IE:/Development/Toolchains/android-ndk-r9c/sources/cxx-stl/gnu-libstdc++/4.8/include/backward -Ijni -DANDROID  -Wa,--noexecstack -Wformat -Werror=format-security -std=c++11 -pthread -DRAGE_ANDROID -DRAGE_DEBUG     -IE:/Development/Toolchains/android-ndk-r9c/platforms/android-18/arch-arm/usr/include -c  jni/../../source/android/main.cpp -o ./obj/local/armeabi-v7a/objs-debug/RAGEAndroid/__/__/source/android/main.o 
[armeabi-v7a] SharedLibrary  : libRAGEAndroid.so
E:/Development/Toolchains/android-ndk-r9c/toolchains/arm-linux-androideabi-4.8/prebuilt/windows-x86_64/bin/arm-linux-androideabi-g++ -Wl,-soname,libRAGEAndroid.so -shared --sysroot=E:/Development/Toolchains/android-ndk-r9c/platforms/android-18/arch-arm ./obj/local/armeabi-v7a/objs-debug/RAGEAndroid/__/__/source/aabb.o #OMITTED OTHER .O FILES# -Wl,--fix-cortex-a8  -Wl,--no-undefined -Wl,-z,noexecstack -Wl,-z,relro -Wl,-z,now  -LE:/Development/Toolchains/android-ndk-r9c/platforms/android-18/arch-arm/usr/lib -llog -landroid -lm -lEGL -lGLESv3 -llog -lc -lm -o ./obj/local/armeabi-v7a/libRAGEAndroid.so
[armeabi-v7a] Install        : libRAGEAndroid.so => libs/armeabi-v7a/libRAGEAndroid.so
copy /b/y ".\obj\local\armeabi-v7a\libRAGEAndroid.so" ".\libs\armeabi-v7a\libRAGEAndroid.so" > NUL
E:/Development/Toolchains/android-ndk-r9c/toolchains/arm-linux-androideabi-4.8/prebuilt/windows-x86_64/bin/arm-linux-androideabi-strip --strip-unneeded  ./libs/armeabi-v7a/libRAGEAndroid.so

As can be seen the file gets compiled with the -g flag and later -O0 is set right before -UNDEBUG -marm -fno-omit-frame-pointer . Also notice that in the last line arm-linux-androideabi-strip --strip-unneeded is performed.

In debug mode the first line of native code called in the main function sleeps to ensure that we have enough time for GDB to connect:

sleep(5);

I right-click on my project and choose "Debug As -> Native Android Application", and GDB outputs the following:

warning: Could not load shared library symbols for 98 libraries, e.g. /system/bin/linker.
Use the "info sharedlibrary" command to see the complete listing.
Do you need "set solib-search-path" or "set sysroot"?
warning: Unable to find dynamic linker breakpoint function.
GDB will retry eventurally.  Meanwhile, it is likely
that GDB is unable to debug shared library initializers
or resolve pending breakpoints after dlopen().
[New Thread 19838]
[New Thread 19840]
[New Thread 19841]
[New Thread 19842]
[New Thread 19843]
[New Thread 19844]
[New Thread 19845]
[New Thread 19846]
[New Thread 19847]
[New Thread 19850]
No symbol table is loaded.  Use the "file" command.

After a while if I pause execution and type info sharedlibrary this is the output:

info sharedlibrary
warning: Could not load shared library symbols for 5 libraries, e.g. eglsubAndroid.so.
Use the "info sharedlibrary" command to see the complete listing.
Do you need "set solib-search-path" or "set sysroot"?
From        To          Syms Read   Shared Object Library
                    No          /system/bin/linker
                    No          libc.so
                    No          libstdc++.so
                    No          libm.so
                    No          liblog.so
                    No          libcutils.so
                    No          libgccdemangle.so
                    No          libcorkscrew.so
                    No          libutils.so
                    No          libbinder.so
                    No          libhardware.so
                    No          libmemtrack.so
                    No          libz.so
                    No          libandroidfw.so
                    No          libexpat.so
                    No          libstlport.so
                    No          libnativehelper.so
                    No          libnetutils.so
                    No          libsync.so
                    No          libui.so
                    No          libGLES_trace.so
                    No          libEGL.so
                    No          libGLESv2.so
                    No          libgui.so
                    No          libinput.so
                    No          libcamera_metadata.so
                    No          libcamera_client.so
                    No          libpng.so
                    No          libft2.so
                    No          libjpeg.so
                    No          libgabi++.so
                    No          libicuuc.so
                    No          libicui18n.so
                    No          libskia.so
                    No          libsqlite.so
                    No          libGLESv1_CM.so
                    No          libETC1.so
                    No          libwpa_client.so
                    No          libhardware_legacy.so
                    No          libselinux.so
                    No          libsonivox.so
                    No          libcrypto.so
                    No          libssl.so
                    No          libstagefright_foundation.so
                    No          libspeexresampler.so
                    No          libaudioutils.so
                    No          libmedia.so
                    No          libusbhost.so
                    No          libharfbuzz_ng.so
                    No          libLLVM.so
                    No          libbcinfo.so
                    No          libbcc.so
                    No          libRS.so
                    No          libRScpp.so
                    No          libhwui.so
                    No          libandroid_runtime.so
                    No          libdvm.so
                    No          libjavacore.so
                    No          memtrack.msm8974.so
                    No          libdrmframework.so
                    No          libdrmframework_jni.so
                    No          libconnectivitymanager.so
                    No          libstagefright_omx.so
                    No          libstagefright_yuv.so
                    No          libvorbisidec.so
                    No          libpowermanager.so
                    No          libstagefright_enc_common.so
                    No          libstagefright_avc_common.so
                    No          libstagefright.so
                    No          libmtp.so
                    No          libexif.so
                    No          libstagefright_amrnb_common.so
                    No          libmedia_jni.so
                    No          libexif_jni.so
                    No          libcommon_time_client.so
                    No          libnbaio.so
                    No          libeffects.so
                    No          libaudioflinger.so
                    No          libvideoeditor_osal.so
                    No          libvideoeditor_videofilters.so
                    No          libvideoeditorplayer.so
                    No          libvideoeditor_core.so
                    No          libvideoeditor_jni.so
                    No          librs_jni.so
                    No          libandroid.so
                    No          libwilhelm.so
                    No          libOpenSLES.so
                    No          libjnigraphics.so
                    No          libwebviewchromium.so
                    No          libwebviewchromium_plat_support.so
                    No          libjavacrypto.so
                    No          libgsl.so
                    No          libadreno_utils.so
                    No          libEGL_adreno.so
                    No          libGLESv1_CM_adreno.so
                    No          libGLESv2_adreno.so
                    No          libGLESv3.so
                    No          libRAGEAndroid.so
                    No          eglsubAndroid.so
                    No          libsc-a3xx.so
                    No          libqdutils.so
                    No          libmemalloc.so
                    No          gralloc.msm8974.so

If I use the file command on the libRAGEAndroid.so library (my library) this is what I get (omitted the full path):

file "#OMITTED PROJECT PATH#/libs/armeabi-v7a/libRAGEAndroid.so"

A program is being debugged already.
Are you sure you want to change the file? (y or n) [answered Y; input not from terminal]
Reading symbols from E:/Cloud/Dropbox/Development/Projects/PC/RAGE (Rajveer Aujla Game Engine)/0.0.21/RAGE/android/libs/armeabi-v7a/libRAGEAndroid.so...done.

WARNING: no debugging symbols found in E:/Cloud/Dropbox/Development/Projects/PC/RAGE (Rajveer Aujla Game Engine)/0.0.21/RAGE/android/libs/armeabi-v7a/libRAGEAndroid.so.
Either the binary was compiled without debugging information
or the debugging information was removed (e.g., with strip or strip -g).
Debugger capabilities will be very limited.
For further information: http://wiki/Main/GdbFaq#No_debugging_symbols_found

If I then replace it with the pre-stripped file from obj/local/armeabi-v7a and then perform the same file command again, I get:

file "E:/Cloud/Dropbox/Development/Projects/PC/RAGE (Rajveer Aujla Game Engine)/0.0.21/RAGE/android/libs/armeabi-v7a/libRAGEAndroid.so"
A program is being debugged already.
Are you sure you want to change the file? (y or n) [answered Y; input not from terminal]
Reading symbols from E:/Cloud/Dropbox/Development/Projects/PC/RAGE (Rajveer Aujla Game Engine)/0.0.21/RAGE/android/libs/armeabi-v7a/libRAGEAndroid.so...done.
Error in re-setting breakpoint 1: Cannot access memory at address 0x14ae08

I'm kind of lost as to where to go from here, so hopefully someone with more experience can help me out!

Answer 1

What ndk plugin is doing behind scenes is generating gdb script and a batch script (on windows) to pull required binaries from device and push right version of gdbserver to the device.

For whatever reason, if you don't get one thing right, one of those moving parts will fail and you will go on goose chase. I don't do NDK debugging as often as AOSP native debugging. When I do, I go with plain vanilla eclipse debug configuration to debug remote C/C++ apps and manually configure gdb and gdb script. You have total control on everything.

Please check Debugging native code of Android Java apps article. You might want to look into generated ndk-gdb script to see which gdb/gdbserver combo that the plugin is using from NDK tools folder. You can copy them to a separate folder and use them in eclipse configuration. You will have to create a dummy c/c++ project pointing to your sources and use that in the remote debug configuration. What you need to keep in mind is that this project is there for debugging, not for building the sources. You should use your NDK project for building code.