为 Android 交叉编译时链接到 libgcc.a 时出错，但符号存在？

Question

我正在尝试交叉编译一个非常简单的 Android 程序，该程序工作 与 android-ndk-r6b 及之前版本，但 不 工作在 android-ndk- r7 及更新版本：

int main() {
  ;
  return 0;
}

我可以在旧版 Android 上使用“agcc”脚本来执行此操作，该脚本可以在 here 找到。我真诚地不想使用 Android.mk 文件来构建它。我知道我可以，但这是我正在做的更大的事情的一部分。因此，我正试图以不同的方式交叉编译它。

无论如何，我尝试构建并获取：

$ 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

因此，关键错误是对 __aeabi_unwind_cpp_pr0 的未定义引用。

经过一番挖掘，这个符号在我链接的 libgcc.a 中：

$ 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

它有一个“T”，告诉我它在代码中的某个地方，对吧？

这里是 arm-eabi-gcc 的详细输出，表明我实际上正在链接到这个库：

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

所以我有点不确定为什么我会得到这个未定义的引用。我已经使用相同的方法与稍有不同的 Android 版本进行交叉编译，没有任何问题。

有什么东西对任何人都很突出吗？

---

编辑：生成的实际命令如下：

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/包括 -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++/包括 -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/包括 -I/home/gnychis/Documents/andr oid/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/拱臂/我们r/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

Answer 1

在哪里可以找到：__aeabi_unwind_cpp_pr0 和其他神秘的未定义函数

（我遇到了与您描述的类似的问题错误，但找到了不同的解决方案，可能对您或其他人有帮助）

我在 Google NDK 包中找到了“libgccunwind.a”库，它定义了许多神秘的函数（它们是 libc.a 和 NDK 包中的其他库引用的函数，但未在标准库中定义）我发现它们在 libgccunwind.a 库中定义：

\sources\android\gccunwind\libs\armeabi

NM 显示它们是在“unwind-arm.o”文件的库中定义的：

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

独立于上面的libgccunwind.a，我搜索了__aeabi_unwind_cpp_pr0和unwind-arm.c和unwind.c，找到了各种c源，例如：

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

这些程序似乎来自类似的来源。我的猜测是，当函数返回或某些事件时，libc.a 中的函数会调用这些“unwind_cpp”（和相关函数），以便这些函数可以执行一些调试或跟踪操作。

无论如何，将该目录添加到 -L 链接器选项和 -lgccunwind 链接器选项（在 -lc 链接器选项之后）允许链接器找到那些“未定义”函数——然后让我解决下一个问题可以交叉编译到 ARM 系统。

Answer 2

这是你的链接，为了清楚起见，分成多行：

/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

如您所见，您自己的目标文件（临时文件）是命令行中的最后一项。这是错误的。如果要正确链接，它至少需要在库之前。

基本上，您的 agcc 脚本正在传递 -nostdlib（这表示您知道得更好），然后手动传递库，但执行顺序完全错误。如果你解决了这个问题，一切都会好起来的。

链接顺序非常重要。 提供符号的对象和库必须链接在需要符号的对象和库之后。

某些版本的工具可以容忍错误的排序，但我认为这是一个错误或错误功能，因为较新的工具链不能，也不应该。大概这个脚本是为其中之一编写的。