error linking to libgcc.a when cross-compiling for

2019-01-24 22:32发布

站内文章 / Android
169 0 0

问题:

I am trying to cross-compile a very simple program for Android that worked with android-ndk-r6b and prior, but does not work on android-ndk-r7 and newer:

int main() {
  ;
  return 0;
}

I was able to do so using an "agcc" script on an older version of Android that can be found here. I'm sincerely not trying to use an Android.mk file to build this. I know I can, but this is part of something much larger I'm working on. So take it for face-value that I am trying to cross-compile this in a different way.

Anyway, I try to build and get:

$ arm-eabi-gcc -o test test.c
/home/gnychis/Documents/android/os/prebuilt/linux-x86/toolchain/arm-eabi-4.4.3/bin/../lib/gcc/arm-eabi/4.4.3/../../../../arm-eabi/bin/ld: warning: /tmp/cc00QD3x.o uses variable-size enums yet the output is to use 32-bit enums; use of enum values across objects may fail
/tmp/cc00QD3x.o:(.ARM.exidx.text.main+0x0): undefined reference to `__aeabi_unwind_cpp_pr0'
collect2: ld returned 1 exit status

So, the key error is the undefined reference to __aeabi_unwind_cpp_pr0.

After doing some digging, this symbol is in libgcc.a which I am linking to:

$ arm-eabi-nm /home/gnychis/Documents/android/os/prebuilt/linux-x86/toolchain/arm-eabi-4.4.3/lib/gcc/arm-eabi/4.4.3/libgcc.a | grep __aeabi_unwind_cpp_pr0
         U __aeabi_unwind_cpp_pr0
         U __aeabi_unwind_cpp_pr0
         U __aeabi_unwind_cpp_pr0
         U __aeabi_unwind_cpp_pr0
         U __aeabi_unwind_cpp_pr0
         U __aeabi_unwind_cpp_pr0
         U __aeabi_unwind_cpp_pr0
00000590 T __aeabi_unwind_cpp_pr0
         U __aeabi_unwind_cpp_pr0
         U __aeabi_unwind_cpp_pr0

It has a 'T' which tells me that it is in the code somewhere, right?

Here is the verbose output of arm-eabi-gcc which shows I am in fact linking to this library:

Using built-in specs.
Target: arm-eabi
Configured with: /home/jingyu/projects/gcc/android-toolchainsrc/build/../gcc/gcc-4.4.3/configure --prefix=/usr/local --target=arm-eabi --host=x86_64-linux-gnu --build=x86_64-linux-gnu --with-gnu-as --with-gnu-ld --enable-languages=c,c++ --with-gmp=/home/jingyu/projects/gcc/toolchain_build/obj/temp-install --with-mpfr=/home/jingyu/projects/gcc/toolchain_build/obj/temp-install --disable-libssp --enable-threads --disable-nls --disable-libmudflap --disable-libgomp --disable-libstdc__-v3 --disable-sjlj-exceptions --disable-shared --disable-tls --with-float=soft --with-fpu=vfp --with-arch=armv5te --enable-target-optspace --with-abi=aapcs --with-gcc-version=4.4.3 --with-binutils-version=2.19 --with-gmp-version=4.2.4 --with-mpfr-version=2.4.1 --with-gdb-version=7.1.x --with-arch=armv5te --with-multilib-list=mandroid --with-sysroot=/usr/local/google/home/android/cupcake_rel_root --program-transform-name='s&^&arm-eabi-&'
Thread model: single
gcc version 4.4.3 (GCC) 
COLLECT_GCC_OPTIONS='-o' 'test' '-I/home/gnychis/Documents/android/os/system/core/include' '-I/home/gnychis/Documents/android/os/hardware/libhardware/include' '-I/home/gnychis/Documents/android/os/hardware/ril/include' '-I/home/gnychis/Documents/android/android-ndk-r7b/platforms/android-9/arch-arm/usr/include' '-I/home/gnychis/Documents/android/os/dalvik/libnativehelper/include' '-I/home/gnychis/Documents/android/os/frameworks/base/include' '-I/home/gnychis/Documents/android/os/external/skia/include' '-I/home/gnychis/Documents/android/os/out/target/product/generic/obj/include' '-I/home/gnychis/Documents/android/os/bionic/libc/arch-arm/include' '-I/home/gnychis/Documents/android/os/bionic/libc/include' '-I/home/gnychis/Documents/android/os/bionic/libstdc++/include' '-I/home/gnychis/Documents/android/os/bionic/libc/kernel/common' '-I/home/gnychis/Documents/android/os/bionic/libc/kernel/arch-arm' '-I/home/gnychis/Documents/android/os/bionic/libm/include' '-I/home/gnychis/Documents/android/os/bionic/libm/include/arch/arm' '-I/home/gnychis/Documents/android/os/bionic/libthread_db/include' '-I/home/gnychis/Documents/android/os/bionic/libm/arm' '-I/home/gnychis/Documents/android/os/bionic/libm' '-I/home/gnychis/Documents/android/os/out/target/product/generic/obj/SHARED_LIBRARIES/libm_intermediates' '-D__ARM_ARCH_5__' '-D__ARM_ARCH_5T__' '-D__ARM_ARCH_5E__' '-D__ARM_ARCH_5TE__' '-DANDROID' '-DSK_RELEASE' '-DNDEBUG' '-UDEBUG' '-march=armv5te' '-mtune=xscale' '-msoft-float' '-mthumb-interwork' '-fpic' '-fno-exceptions' '-ffunction-sections' '-funwind-tables' '-fstack-protector' '-fmessage-length=0' '-Bdynamic' '-L/home/gnychis/Documents/android/android-ndk-r7b/platforms/android-9/arch-arm/usr/lib' '-nostdlib' '-v' '-mfpu=vfp' '-mabi=aapcs'
 /home/gnychis/Documents/android/os/prebuilt/linux-x86/toolchain/arm-eabi-4.4.3/bin/../libexec/gcc/arm-eabi/4.4.3/cc1 -quiet -v -I/home/gnychis/Documents/android/os/system/core/include -I/home/gnychis/Documents/android/os/hardware/libhardware/include -I/home/gnychis/Documents/android/os/hardware/ril/include -I/home/gnychis/Documents/android/android-ndk-r7b/platforms/android-9/arch-arm/usr/include -I/home/gnychis/Documents/android/os/dalvik/libnativehelper/include -I/home/gnychis/Documents/android/os/frameworks/base/include -I/home/gnychis/Documents/android/os/external/skia/include -I/home/gnychis/Documents/android/os/out/target/product/generic/obj/include -I/home/gnychis/Documents/android/os/bionic/libc/arch-arm/include -I/home/gnychis/Documents/android/os/bionic/libc/include -I/home/gnychis/Documents/android/os/bionic/libstdc++/include -I/home/gnychis/Documents/android/os/bionic/libc/kernel/common -I/home/gnychis/Documents/android/os/bionic/libc/kernel/arch-arm -I/home/gnychis/Documents/android/os/bionic/libm/include -I/home/gnychis/Documents/android/os/bionic/libm/include/arch/arm -I/home/gnychis/Documents/android/os/bionic/libthread_db/include -I/home/gnychis/Documents/android/os/bionic/libm/arm -I/home/gnychis/Documents/android/os/bionic/libm -I/home/gnychis/Documents/android/os/out/target/product/generic/obj/SHARED_LIBRARIES/libm_intermediates -iprefix /home/gnychis/Documents/android/os/prebuilt/linux-x86/toolchain/arm-eabi-4.4.3/bin/../lib/gcc/arm-eabi/4.4.3/ -D__USES_INITFINI__ -D__ARM_ARCH_5__ -D__ARM_ARCH_5T__ -D__ARM_ARCH_5E__ -D__ARM_ARCH_5TE__ -DANDROID -DSK_RELEASE -DNDEBUG -UDEBUG test.c -quiet -dumpbase test.c -march=armv5te -mtune=xscale -msoft-float -mthumb-interwork -mfpu=vfp -mabi=aapcs -auxbase test -version -fpic -fno-exceptions -ffunction-sections -funwind-tables -fstack-protector -fmessage-length=0 -o /tmp/ccIIp1N2.s
GNU C (GCC) version 4.4.3 (arm-eabi)
    compiled by GNU C version 4.2.4 (Ubuntu 4.2.4-1ubuntu4), GMP version 4.2.4, MPFR version 2.4.1.
GGC heuristics: --param ggc-min-expand=98 --param ggc-min-heapsize=128206
ignoring nonexistent directory "/home/gnychis/Documents/android/os/prebuilt/linux-x86/toolchain/arm-eabi-4.4.3/bin/../lib/gcc/arm-eabi/4.4.3/../../../../arm-eabi/include"
ignoring nonexistent directory "/usr/local/google/home/android/cupcake_rel_root/usr/local/include"
ignoring duplicate directory "/home/gnychis/Documents/android/os/prebuilt/linux-x86/toolchain/arm-eabi-4.4.3/bin/../lib/gcc/../../lib/gcc/arm-eabi/4.4.3/include"
ignoring duplicate directory "/home/gnychis/Documents/android/os/prebuilt/linux-x86/toolchain/arm-eabi-4.4.3/bin/../lib/gcc/../../lib/gcc/arm-eabi/4.4.3/include-fixed"
ignoring nonexistent directory "/home/gnychis/Documents/android/os/prebuilt/linux-x86/toolchain/arm-eabi-4.4.3/bin/../lib/gcc/../../lib/gcc/arm-eabi/4.4.3/../../../../arm-eabi/include"
ignoring nonexistent directory "/usr/local/google/home/android/cupcake_rel_root/usr/include"
ignoring nonexistent directory "/home/gnychis/Documents/android/os/out/target/product/generic/obj/include"
ignoring nonexistent directory "/home/gnychis/Documents/android/os/bionic/libm/include/arch/arm"
ignoring nonexistent directory "/home/gnychis/Documents/android/os/out/target/product/generic/obj/SHARED_LIBRARIES/libm_intermediates"
#include "..." search starts here:
#include <...> search starts here:
 /home/gnychis/Documents/android/os/system/core/include
 /home/gnychis/Documents/android/os/hardware/libhardware/include
 /home/gnychis/Documents/android/os/hardware/ril/include
 /home/gnychis/Documents/android/android-ndk-r7b/platforms/android-9/arch-arm/usr/include
 /home/gnychis/Documents/android/os/dalvik/libnativehelper/include
 /home/gnychis/Documents/android/os/frameworks/base/include
 /home/gnychis/Documents/android/os/external/skia/include
 /home/gnychis/Documents/android/os/bionic/libc/arch-arm/include
 /home/gnychis/Documents/android/os/bionic/libc/include
 /home/gnychis/Documents/android/os/bionic/libstdc++/include
 /home/gnychis/Documents/android/os/bionic/libc/kernel/common
 /home/gnychis/Documents/android/os/bionic/libc/kernel/arch-arm
 /home/gnychis/Documents/android/os/bionic/libm/include
 /home/gnychis/Documents/android/os/bionic/libthread_db/include
 /home/gnychis/Documents/android/os/bionic/libm/arm
 /home/gnychis/Documents/android/os/bionic/libm
 /home/gnychis/Documents/android/os/prebuilt/linux-x86/toolchain/arm-eabi-4.4.3/bin/../lib/gcc/arm-eabi/4.4.3/include
 /home/gnychis/Documents/android/os/prebuilt/linux-x86/toolchain/arm-eabi-4.4.3/bin/../lib/gcc/arm-eabi/4.4.3/include-fixed
End of search list.
GNU C (GCC) version 4.4.3 (arm-eabi)
    compiled by GNU C version 4.2.4 (Ubuntu 4.2.4-1ubuntu4), GMP version 4.2.4, MPFR version 2.4.1.
GGC heuristics: --param ggc-min-expand=98 --param ggc-min-heapsize=128206
Compiler executable checksum: c575b4a30c8a516a84cf6e49f2cb23d1
COLLECT_GCC_OPTIONS='-o' 'test' '-I/home/gnychis/Documents/android/os/system/core/include' '-I/home/gnychis/Documents/android/os/hardware/libhardware/include' '-I/home/gnychis/Documents/android/os/hardware/ril/include' '-I/home/gnychis/Documents/android/android-ndk-r7b/platforms/android-9/arch-arm/usr/include' '-I/home/gnychis/Documents/android/os/dalvik/libnativehelper/include' '-I/home/gnychis/Documents/android/os/frameworks/base/include' '-I/home/gnychis/Documents/android/os/external/skia/include' '-I/home/gnychis/Documents/android/os/out/target/product/generic/obj/include' '-I/home/gnychis/Documents/android/os/bionic/libc/arch-arm/include' '-I/home/gnychis/Documents/android/os/bionic/libc/include' '-I/home/gnychis/Documents/android/os/bionic/libstdc++/include' '-I/home/gnychis/Documents/android/os/bionic/libc/kernel/common' '-I/home/gnychis/Documents/android/os/bionic/libc/kernel/arch-arm' '-I/home/gnychis/Documents/android/os/bionic/libm/include' '-I/home/gnychis/Documents/android/os/bionic/libm/include/arch/arm' '-I/home/gnychis/Documents/android/os/bionic/libthread_db/include' '-I/home/gnychis/Documents/android/os/bionic/libm/arm' '-I/home/gnychis/Documents/android/os/bionic/libm' '-I/home/gnychis/Documents/android/os/out/target/product/generic/obj/SHARED_LIBRARIES/libm_intermediates' '-D__ARM_ARCH_5__' '-D__ARM_ARCH_5T__' '-D__ARM_ARCH_5E__' '-D__ARM_ARCH_5TE__' '-DANDROID' '-DSK_RELEASE' '-DNDEBUG' '-UDEBUG' '-march=armv5te' '-mtune=xscale' '-msoft-float' '-mthumb-interwork' '-fpic' '-fno-exceptions' '-ffunction-sections' '-funwind-tables' '-fstack-protector' '-fmessage-length=0' '-Bdynamic' '-L/home/gnychis/Documents/android/android-ndk-r7b/platforms/android-9/arch-arm/usr/lib' '-nostdlib' '-v' '-mfpu=vfp' '-mabi=aapcs'
 /home/gnychis/Documents/android/os/prebuilt/linux-x86/toolchain/arm-eabi-4.4.3/bin/../lib/gcc/arm-eabi/4.4.3/../../../../arm-eabi/bin/as -v -I/home/gnychis/Documents/android/os/system/core/include -I/home/gnychis/Documents/android/os/hardware/libhardware/include -I/home/gnychis/Documents/android/os/hardware/ril/include -I/home/gnychis/Documents/android/android-ndk-r7b/platforms/android-9/arch-arm/usr/include -I/home/gnychis/Documents/android/os/dalvik/libnativehelper/include -I/home/gnychis/Documents/android/os/frameworks/base/include -I/home/gnychis/Documents/android/os/external/skia/include -I/home/gnychis/Documents/android/os/out/target/product/generic/obj/include -I/home/gnychis/Documents/android/os/bionic/libc/arch-arm/include -I/home/gnychis/Documents/android/os/bionic/libc/include -I/home/gnychis/Documents/android/os/bionic/libstdc++/include -I/home/gnychis/Documents/android/os/bionic/libc/kernel/common -I/home/gnychis/Documents/android/os/bionic/libc/kernel/arch-arm -I/home/gnychis/Documents/android/os/bionic/libm/include -I/home/gnychis/Documents/android/os/bionic/libm/include/arch/arm -I/home/gnychis/Documents/android/os/bionic/libthread_db/include -I/home/gnychis/Documents/android/os/bionic/libm/arm -I/home/gnychis/Documents/android/os/bionic/libm -I/home/gnychis/Documents/android/os/out/target/product/generic/obj/SHARED_LIBRARIES/libm_intermediates -march=armv5te -mthumb-interwork -mfloat-abi=soft -mfpu=vfp -meabi=5 -o /tmp/ccGAKjxX.o /tmp/ccIIp1N2.s
GNU assembler version 2.19 (arm-eabi) using BFD version (GNU Binutils) 2.19
COMPILER_PATH=/home/gnychis/Documents/android/os/prebuilt/linux-x86/toolchain/arm-eabi-4.4.3/bin/../libexec/gcc/arm-eabi/4.4.3/:/home/gnychis/Documents/android/os/prebuilt/linux-x86/toolchain/arm-eabi-4.4.3/bin/../libexec/gcc/:/home/gnychis/Documents/android/os/prebuilt/linux-x86/toolchain/arm-eabi-4.4.3/bin/../lib/gcc/arm-eabi/4.4.3/../../../../arm-eabi/bin/
LIBRARY_PATH=/home/gnychis/Documents/android/os/prebuilt/linux-x86/toolchain/arm-eabi-4.4.3/bin/../lib/gcc/arm-eabi/4.4.3/:/home/gnychis/Documents/android/os/prebuilt/linux-x86/toolchain/arm-eabi-4.4.3/bin/../lib/gcc/:/home/gnychis/Documents/android/os/prebuilt/linux-x86/toolchain/arm-eabi-4.4.3/bin/../lib/gcc/arm-eabi/4.4.3/../../../../arm-eabi/lib/
COLLECT_GCC_OPTIONS='-o' 'test' '-I/home/gnychis/Documents/android/os/system/core/include' '-I/home/gnychis/Documents/android/os/hardware/libhardware/include' '-I/home/gnychis/Documents/android/os/hardware/ril/include' '-I/home/gnychis/Documents/android/android-ndk-r7b/platforms/android-9/arch-arm/usr/include' '-I/home/gnychis/Documents/android/os/dalvik/libnativehelper/include' '-I/home/gnychis/Documents/android/os/frameworks/base/include' '-I/home/gnychis/Documents/android/os/external/skia/include' '-I/home/gnychis/Documents/android/os/out/target/product/generic/obj/include' '-I/home/gnychis/Documents/android/os/bionic/libc/arch-arm/include' '-I/home/gnychis/Documents/android/os/bionic/libc/include' '-I/home/gnychis/Documents/android/os/bionic/libstdc++/include' '-I/home/gnychis/Documents/android/os/bionic/libc/kernel/common' '-I/home/gnychis/Documents/android/os/bionic/libc/kernel/arch-arm' '-I/home/gnychis/Documents/android/os/bionic/libm/include' '-I/home/gnychis/Documents/android/os/bionic/libm/include/arch/arm' '-I/home/gnychis/Documents/android/os/bionic/libthread_db/include' '-I/home/gnychis/Documents/android/os/bionic/libm/arm' '-I/home/gnychis/Documents/android/os/bionic/libm' '-I/home/gnychis/Documents/android/os/out/target/product/generic/obj/SHARED_LIBRARIES/libm_intermediates' '-D__ARM_ARCH_5__' '-D__ARM_ARCH_5T__' '-D__ARM_ARCH_5E__' '-D__ARM_ARCH_5TE__' '-DANDROID' '-DSK_RELEASE' '-DNDEBUG' '-UDEBUG' '-march=armv5te' '-mtune=xscale' '-msoft-float' '-mthumb-interwork' '-fpic' '-fno-exceptions' '-ffunction-sections' '-funwind-tables' '-fstack-protector' '-fmessage-length=0' '-Bdynamic' '-L/home/gnychis/Documents/android/android-ndk-r7b/platforms/android-9/arch-arm/usr/lib' '-nostdlib' '-v' '-mfpu=vfp' '-mabi=aapcs'
 /home/gnychis/Documents/android/os/prebuilt/linux-x86/toolchain/arm-eabi-4.4.3/bin/../libexec/gcc/arm-eabi/4.4.3/collect2 --sysroot=/usr/local/google/home/android/cupcake_rel_root -X -o test -L/home/gnychis/Documents/android/android-ndk-r7b/platforms/android-9/arch-arm/usr/lib -L/home/gnychis/Documents/android/os/prebuilt/linux-x86/toolchain/arm-eabi-4.4.3/bin/../lib/gcc/arm-eabi/4.4.3 -L/home/gnychis/Documents/android/os/prebuilt/linux-x86/toolchain/arm-eabi-4.4.3/bin/../lib/gcc -L/home/gnychis/Documents/android/os/prebuilt/linux-x86/toolchain/arm-eabi-4.4.3/bin/../lib/gcc/arm-eabi/4.4.3/../../../../arm-eabi/lib -T /home/gnychis/Documents/android/os/prebuilt/linux-x86/toolchain/arm-eabi-4.4.3/arm-eabi/lib/ldscripts/armelf.x -dynamic-linker /system/bin/linker --gc-sections -z nocopyreloc --no-undefined -rpath-link=/home/gnychis/Documents/android/android-ndk-r7b/platforms/android-9/arch-arm/usr/lib /home/gnychis/Documents/android/android-ndk-r7b/platforms/android-9/arch-arm/usr/lib/crtend_android.o /home/gnychis/Documents/android/android-ndk-r7b/platforms/android-9/arch-arm/usr/lib/crtbegin_dynamic.o /home/gnychis/Documents/android/os/prebuilt/linux-x86/toolchain/arm-eabi-4.4.3/lib32/libiberty.a /home/gnychis/Documents/android/os/prebuilt/linux-x86/toolchain/arm-eabi-4.4.3/lib/gcc/arm-eabi/4.4.3/libgcc.a -lc -lm /tmp/ccGAKjxX.o
/home/gnychis/Documents/android/os/prebuilt/linux-x86/toolchain/arm-eabi-4.4.3/bin/../lib/gcc/arm-eabi/4.4.3/../../../../arm-eabi/bin/ld: warning: /tmp/ccGAKjxX.o uses variable-size enums yet the output is to use 32-bit enums; use of enum values across objects may fail
/tmp/ccGAKjxX.o:(.ARM.exidx.text.main+0x0): undefined reference to `__aeabi_unwind_cpp_pr0'
collect2: ld returned 1 exit status

So I'm just a bit unsure why I am getting this undefined reference. I have used this same method of cross-compiling with a slightly different version of Android and had no issue.

Does anything stand out to anyone?

EDIT: The actual command generated is the following:

arm-eabi-gcc -o test -I/home/gnychis/Documents/android/os/system/core/include -I/home/gnychis/Documents/android/os/hardware/libhardware/include -I/home/gnychis/Documents/android/os/hardware/ril/include -I/home/gnychis/Documents/android/os/dalvik/libnativehelper/include -I/home/gnychis/Documents/android/os/frameworks/base/include -I/home/gnychis/Documents/android/os/external/skia/include -I/home/gnychis/Documents/android/os/out/target/product/generic/obj/include -I/home/gnychis/Documents/android/os/bionic/libc/arch-arm/include -I/home/gnychis/Documents/android/os/bionic/libc/include -I/home/gnychis/Documents/android/os/bionic/libstdc++/include -I/home/gnychis/Documents/android/os/bionic/libc/kernel/common -I/home/gnychis/Documents/android/os/bionic/libc/kernel/arch-arm -I/home/gnychis/Documents/android/os/bionic/libm/include -I/home/gnychis/Documents/android/os/bionic/libm/include/arch/arm -I/home/gnychis/Documents/android/os/bionic/libthread_db/include -I/home/gnychis/Documents/android/os/bionic/libm/arm -I/home/gnychis/Documents/android/os/bionic/libm -I/home/gnychis/Documents/android/os/out/target/product/generic/obj/SHARED_LIBRARIES/libm_intermediates -D__ARM_ARCH_5__ -D__ARM_ARCH_5T__ -D__ARM_ARCH_5E__ -D__ARM_ARCH_5TE__ -DANDROID -DSK_RELEASE -DNDEBUG -include /home/gnychis/Documents/android/os/system/core/include/arch/linux-arm/AndroidConfig.h -UDEBUG -march=armv5te -mtune=xscale -msoft-float -mthumb-interwork -fpic -fno-exceptions -ffunction-sections -funwind-tables -fstack-protector -fmessage-length=0 -Bdynamic -Wl,-T,/home/gnychis/Documents/android/os/build/core/armelf.x -Wl,-dynamic-linker,/system/bin/linker -Wl,--gc-sections -Wl,-z,nocopyreloc -Wl,--no-undefined -Wl,-rpath-link=/home/gnychis/Documents/android/os/../android-ndk-r7b/platforms/android-9/arch-arm/usr/lib -L/home/gnychis/Documents/android/os/../android-ndk-r7b/platforms/android-9/arch-arm/usr/lib -nostdlib /home/gnychis/Documents/android/os/../android-ndk-r7b/platforms/android-9/arch-arm/usr/lib/crtend_android.o /home/gnychis/Documents/android/os/../android-ndk-r7b/platforms/android-9/arch-arm/usr/lib/crtbegin_dynamic.o /home/gnychis/Documents/android/os/prebuilt/linux-x86/toolchain/arm-eabi-4.4.3/lib/gcc/arm-eabi/4.4.3/libgcc.a -lc -lm test.c

回答1:

Here's your link like, broken out into multiple lines for clarity:

/home/gnychis/Documents/android/os/prebuilt/linux-x86/toolchain/arm-eabi-4.4.3/bin/../libexec/gcc/arm-eabi/4.4.3/collect2 \
  --sysroot=/usr/local/google/home/android/cupcake_rel_root \
  -X \
  -o test \
  -L/home/gnychis/Documents/android/android-ndk-r7b/platforms/android-9/arch-arm/usr/lib \
  -L/home/gnychis/Documents/android/os/prebuilt/linux-x86/toolchain/arm-eabi-4.4.3/bin/../lib/gcc/arm-eabi/4.4.3 \
  -L/home/gnychis/Documents/android/os/prebuilt/linux-x86/toolchain/arm-eabi-4.4.3/bin/../lib/gcc
  -L/home/gnychis/Documents/android/os/prebuilt/linux-x86/toolchain/arm-eabi-4.4.3/bin/../lib/gcc/arm-eabi/4.4.3/../../../../arm-eabi/lib
  -T /home/gnychis/Documents/android/os/prebuilt/linux-x86/toolchain/arm-eabi-4.4.3/arm-eabi/lib/ldscripts/armelf.x \
  -dynamic-linker /system/bin/linker \
  --gc-sections \
  -z nocopyreloc \
  --no-undefined \
  -rpath-link=/home/gnychis/Documents/android/android-ndk-r7b/platforms/android-9/arch-arm/usr/lib \
  /home/gnychis/Documents/android/android-ndk-r7b/platforms/android-9/arch-arm/usr/lib/crtend_android.o \
  /home/gnychis/Documents/android/android-ndk-r7b/platforms/android-9/arch-arm/usr/lib/crtbegin_dynamic.o \
  /home/gnychis/Documents/android/os/prebuilt/linux-x86/toolchain/arm-eabi-4.4.3/lib32/libiberty.a \
  /home/gnychis/Documents/android/os/prebuilt/linux-x86/toolchain/arm-eabi-4.4.3/lib/gcc/arm-eabi/4.4.3/libgcc.a \
  -lc \
  -lm \
  /tmp/ccGAKjxX.o

As you can see, your own object file (the temporary one) is the very last item on the command line. This is just wrong. It needs to be before the libraries, at least, if it is to link correctly.

Basically, your agcc script is passing -nostdlib (which says that you know better) and then passing the libraries manually, but doing it in completely the wrong order. If you fix this, all should be well.

Link order is very important. Objects and libraries that provide symbols must be linked after objects and libraries that require symbols.

There were certain versions of the tools that could tolerate bad ordering, but I think that was a bug, or mis-feature, because newer toolchains cannot, and should not. Presumably this script was written for one of those.



回答2:

Where to find: __aeabi_unwind_cpp_pr0 and other mysterious, undefined functions

(I had a similar problem error to what you describe, but found a different solution, that may be helpful to you or others)

I found 'libgccunwind.a' library in the Google NDK package which defines a number of these mysterious functions (they are functions referenced by libc.a and other libraries in the NDK package, but not defined in a standard library) I found them defined in a libgccunwind.a library in:

\sources\android\gccunwind\libs\armeabi

NM shows that they are defined in that lib from an 'unwind-arm.o' file:

nm libgccunwind.a

unwind-arm.o:
         U _GLOBAL_OFFSET_TABLE_
00000cf8 T _Unwind_Complete
00000cfc T _Unwind_DeleteException
00000ba4 T _Unwind_GetCFA
00000408 t _Unwind_GetGR
00000474 t _Unwind_SetGR
000003c4 T _Unwind_VRS_Get
0000084c T _Unwind_VRS_Pop
00000430 T _Unwind_VRS_Set
00000844 T __aeabi_unwind_cpp_pr0
0000083c W __aeabi_unwind_cpp_pr1
00000834 W __aeabi_unwind_cpp_pr2
         w __cxa_begin_cleanup
         w __cxa_call_unexpected
         w __cxa_type_match
         U __exidx_end
         U __exidx_start
00000d1c T __gnu_Unwind_Backtrace
         w __gnu_Unwind_Find_exidx

Independant of the libgccunwind.a above, I searched for __aeabi_unwind_cpp_pr0 and unwind-arm.c and unwind.c, and found various c source, for example:

http://lxr.free-electrons.com/source/arch/arm/kernel/unwind.c?a=arm

http://opensource.apple.com/source/gcc/gcc-5646/gcc/config/arm/unwind-arm.c

These programs seem to be derived from a similar source. My guess is that these 'unwind_cpp' (and related functions) are called by the functions in libc.a when a function returns or on certain events so that these functions can perform some debugging or tracing operation.

In any event, adding that directory in a -L linker option and -lgccunwind linker option (after the -lc linker option) allowed the linker to find those 'undefined' functions -- and let me get to the next problem I have in cross compiling to ARM systems.



标签： android gcc linker android-ndk cross-compiling
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