gcc 和 ${CC} 的区别

Question

最近我得到了一块 NXP imx8 板。 我想测试我的程序。 但它不适用于imx8。

当我使用 aarch64-poky-linux-gcc

$ source /opt/fsl-imx-internal-xwayland/5.15-kirkstone/environment-setup-armv8a-poky-linux
$ aarch64-poky-linux-gcc -o hello hello.c
In file included from hello.c:1:
/opt/fsl-imx-internal-xwayland/5.15-kirkstone/sysroots/x86_64-pokysdk-linux/usr/lib/aarch64-poky-linux/gcc/aarch64-poky-linux/11.2.0/include/stdio.h:27:10: fatal error: bits/libc-header-start.h: No such file or directory
   27 | #include <bits/libc-header-start.h>
      |          ^~~~~~~~~~~~~~~~~~~~~~~~~~
compilation terminated.

当我使用 ${CC}

$ source /opt/fsl-imx-internal-xwayland/5.15-kirkstone/environment-setup-armv8a-poky-linux

${CC} -o hello hello.c # it can work

所以我想知道原因。 我做这件事：

$ echo 'main(){}'|aarch64-poky-linux-gcc -E -v -
Using built-in specs.
COLLECT_GCC=aarch64-poky-linux-gcc
Target: aarch64-poky-linux
Configured with: ../../../../../../work-shared/gcc-11.2.0-r0/gcc-11.2.0/configure --build=x86_64-linux --host=x86_64-pokysdk-linux --target=aarch64-poky-linux --prefix=/usr/local/oe-sdk-hardcoded-buildpath/sysroots/x86_64-pokysdk-linux/usr --exec_prefix=/usr/local/oe-sdk-hardcoded-buildpath/sysroots/x86_64-pokysdk-linux/usr --bindir=/usr/local/oe-sdk-hardcoded-buildpath/sysroots/x86_64-pokysdk-linux/usr/bin/aarch64-poky-linux --sbindir=/usr/local/oe-sdk-hardcoded-buildpath/sysroots/x86_64-pokysdk-linux/usr/bin/aarch64-poky-linux --libexecdir=/usr/local/oe-sdk-hardcoded-buildpath/sysroots/x86_64-pokysdk-linux/usr/libexec/aarch64-poky-linux --datadir=/usr/local/oe-sdk-hardcoded-buildpath/sysroots/x86_64-pokysdk-linux/usr/share --sysconfdir=/usr/local/oe-sdk-hardcoded-buildpath/sysroots/x86_64-pokysdk-linux/etc --sharedstatedir=/usr/local/oe-sdk-hardcoded-buildpath/sysroots/x86_64-pokysdk-linux/com --localstatedir=/usr/local/oe-sdk-hardcoded-buildpath/sysroots/x86_64-pokysdk-linux/var --libdir=/usr/local/oe-sdk-hardcoded-buildpath/sysroots/x86_64-pokysdk-linux/usr/lib/aarch64-poky-linux --includedir=/usr/local/oe-sdk-hardcoded-buildpath/sysroots/x86_64-pokysdk-linux/usr/include --oldincludedir=/usr/local/oe-sdk-hardcoded-buildpath/sysroots/x86_64-pokysdk-linux/usr/include --infodir=/usr/local/oe-sdk-hardcoded-buildpath/sysroots/x86_64-pokysdk-linux/usr/share/info --mandir=/usr/local/oe-sdk-hardcoded-buildpath/sysroots/x86_64-pokysdk-linux/usr/share/man --disable-silent-rules --disable-dependency-tracking --with-libtool-sysroot=/home/bamboo/build/5.15-kirkstone-full/fsl-imx-internal-xwayland/mx8m/yocto/build/tmp/work/x86_64-nativesdk-pokysdk-linux/gcc-cross-canadian-aarch64/11.2.0-r0/recipe-sysroot --with-gnu-ld --enable-shared --enable-languages=c,c++ --enable-threads=posix --enable-multilib --enable-default-pie --enable-c99 --enable-long-long --enable-symvers=gnu --enable-libstdcxx-pch --program-prefix=aarch64-poky-linux- --without-local-prefix --disable-install-libiberty --disable-libssp --enable-libitm --enable-lto --disable-bootstrap --with-system-zlib --with-linker-hash-style=gnu --enable-linker-build-id --with-ppl=no --with-cloog=no --enable-checking=release --enable-cheaders=c_global --without-isl --with-gxx-include-dir=/not/exist/usr/include/c++/11.2.0 --with-build-time-tools=/home/bamboo/build/5.15-kirkstone-full/fsl-imx-internal-xwayland/mx8m/yocto/build/tmp/work/x86_64-nativesdk-pokysdk-linux/gcc-cross-canadian-aarch64/11.2.0-r0/recipe-sysroot-native/usr/aarch64-poky-linux/bin --with-sysroot=/not/exist --with-build-sysroot=/home/bamboo/build/5.15-kirkstone-full/fsl-imx-internal-xwayland/mx8m/yocto/build/tmp/work/x86_64-nativesdk-pokysdk-linux/gcc-cross-canadian-aarch64/11.2.0-r0/recipe-sysroot --enable-standard-branch-protection --enable-poison-system-directories --disable-static --enable-nls --with-glibc-version=2.28 --enable-initfini-array --enable-__cxa_atexit
Thread model: posix
Supported LTO compression algorithms: zlib zstd
gcc version 11.2.0 (GCC)
COLLECT_GCC_OPTIONS='-E' '-v' '-mlittle-endian' '-mabi=lp64'
 /opt/fsl-imx-internal-xwayland/5.15-kirkstone/sysroots/x86_64-pokysdk-linux/usr/libexec/aarch64-poky-linux/gcc/aarch64-poky-linux/11.2.0/cc1 -E -quiet -v - -mlittle-endian -mabi=lp64 -dumpbase -
ignoring nonexistent directory "/not/exist/usr/lib/aarch64-poky-linux/11.2.0/include"
ignoring nonexistent directory "/not/exist/usr/local/include"
ignoring nonexistent directory "/opt/fsl-imx-internal-xwayland/5.15-kirkstone/sysroots/x86_64-pokysdk-linux/usr/lib/aarch64-poky-linux/gcc/aarch64-poky-linux/11.2.0/../../../../../aarch64-poky-linux/include"
ignoring nonexistent directory "/not/exist/usr/include/"
#include "..." search starts here:
#include <...> search starts here:
 /opt/fsl-imx-internal-xwayland/5.15-kirkstone/sysroots/x86_64-pokysdk-linux/usr/lib/aarch64-poky-linux/gcc/aarch64-poky-linux/11.2.0/include
 /opt/fsl-imx-internal-xwayland/5.15-kirkstone/sysroots/x86_64-pokysdk-linux/usr/lib/aarch64-poky-linux/gcc/aarch64-poky-linux/11.2.0/include-fixed
End of search list.
# 0 "<stdin>"
# 0 "<built-in>"
# 0 "<command-line>"
# 1 "<stdin>"
main(){}
COMPILER_PATH=/opt/fsl-imx-internal-xwayland/5.15-kirkstone/sysroots/x86_64-pokysdk-linux/usr/libexec/aarch64-poky-linux/gcc/aarch64-poky-linux/11.2.0/:/opt/fsl-imx-internal-xwayland/5.15-kirkstone/sysroots/x86_64-pokysdk-linux/usr/libexec/aarch64-poky-linux/gcc/aarch64-poky-linux/11.2.0/:/opt/fsl-imx-internal-xwayland/5.15-kirkstone/sysroots/x86_64-pokysdk-linux/usr/libexec/aarch64-poky-linux/gcc/aarch64-poky-linux/:/opt/fsl-imx-internal-xwayland/5.15-kirkstone/sysroots/x86_64-pokysdk-linux/usr/lib/aarch64-poky-linux/gcc/aarch64-poky-linux/11.2.0/:/opt/fsl-imx-internal-xwayland/5.15-kirkstone/sysroots/x86_64-pokysdk-linux/usr/lib/aarch64-poky-linux/gcc/aarch64-poky-linux/
LIBRARY_PATH=/opt/fsl-imx-internal-xwayland/5.15-kirkstone/sysroots/x86_64-pokysdk-linux/usr/lib/aarch64-poky-linux/gcc/aarch64-poky-linux/11.2.0/
COLLECT_GCC_OPTIONS='-E' '-v' '-mlittle-endian' '-mabi=lp64'

$ echo 'main(){}'|${CC} -E -v -
Using built-in specs.
COLLECT_GCC=aarch64-poky-linux-gcc
Target: aarch64-poky-linux
Configured with: ../../../../../../work-shared/gcc-11.2.0-r0/gcc-11.2.0/configure --build=x86_64-linux --host=x86_64-pokysdk-linux --target=aarch64-poky-linux --prefix=/usr/local/oe-sdk-hardcoded-buildpath/sysroots/x86_64-pokysdk-linux/usr --exec_prefix=/usr/local/oe-sdk-hardcoded-buildpath/sysroots/x86_64-pokysdk-linux/usr --bindir=/usr/local/oe-sdk-hardcoded-buildpath/sysroots/x86_64-pokysdk-linux/usr/bin/aarch64-poky-linux --sbindir=/usr/local/oe-sdk-hardcoded-buildpath/sysroots/x86_64-pokysdk-linux/usr/bin/aarch64-poky-linux --libexecdir=/usr/local/oe-sdk-hardcoded-buildpath/sysroots/x86_64-pokysdk-linux/usr/libexec/aarch64-poky-linux --datadir=/usr/local/oe-sdk-hardcoded-buildpath/sysroots/x86_64-pokysdk-linux/usr/share --sysconfdir=/usr/local/oe-sdk-hardcoded-buildpath/sysroots/x86_64-pokysdk-linux/etc --sharedstatedir=/usr/local/oe-sdk-hardcoded-buildpath/sysroots/x86_64-pokysdk-linux/com --localstatedir=/usr/local/oe-sdk-hardcoded-buildpath/sysroots/x86_64-pokysdk-linux/var --libdir=/usr/local/oe-sdk-hardcoded-buildpath/sysroots/x86_64-pokysdk-linux/usr/lib/aarch64-poky-linux --includedir=/usr/local/oe-sdk-hardcoded-buildpath/sysroots/x86_64-pokysdk-linux/usr/include --oldincludedir=/usr/local/oe-sdk-hardcoded-buildpath/sysroots/x86_64-pokysdk-linux/usr/include --infodir=/usr/local/oe-sdk-hardcoded-buildpath/sysroots/x86_64-pokysdk-linux/usr/share/info --mandir=/usr/local/oe-sdk-hardcoded-buildpath/sysroots/x86_64-pokysdk-linux/usr/share/man --disable-silent-rules --disable-dependency-tracking --with-libtool-sysroot=/home/bamboo/build/5.15-kirkstone-full/fsl-imx-internal-xwayland/mx8m/yocto/build/tmp/work/x86_64-nativesdk-pokysdk-linux/gcc-cross-canadian-aarch64/11.2.0-r0/recipe-sysroot --with-gnu-ld --enable-shared --enable-languages=c,c++ --enable-threads=posix --enable-multilib --enable-default-pie --enable-c99 --enable-long-long --enable-symvers=gnu --enable-libstdcxx-pch --program-prefix=aarch64-poky-linux- --without-local-prefix --disable-install-libiberty --disable-libssp --enable-libitm --enable-lto --disable-bootstrap --with-system-zlib --with-linker-hash-style=gnu --enable-linker-build-id --with-ppl=no --with-cloog=no --enable-checking=release --enable-cheaders=c_global --without-isl --with-gxx-include-dir=/not/exist/usr/include/c++/11.2.0 --with-build-time-tools=/home/bamboo/build/5.15-kirkstone-full/fsl-imx-internal-xwayland/mx8m/yocto/build/tmp/work/x86_64-nativesdk-pokysdk-linux/gcc-cross-canadian-aarch64/11.2.0-r0/recipe-sysroot-native/usr/aarch64-poky-linux/bin --with-sysroot=/not/exist --with-build-sysroot=/home/bamboo/build/5.15-kirkstone-full/fsl-imx-internal-xwayland/mx8m/yocto/build/tmp/work/x86_64-nativesdk-pokysdk-linux/gcc-cross-canadian-aarch64/11.2.0-r0/recipe-sysroot --enable-standard-branch-protection --enable-poison-system-directories --disable-static --enable-nls --with-glibc-version=2.28 --enable-initfini-array --enable-__cxa_atexit
Thread model: posix
Supported LTO compression algorithms: zlib zstd
gcc version 11.2.0 (GCC)
COLLECT_GCC_OPTIONS='-march=armv8-a+crc+crypto' '-fstack-protector-strong' '-O2' '-D' '_FORTIFY_SOURCE=2' '-Wformat=1' '-Wformat-security' '-Werror=format-security' '-E' '-v' '-mlittle-endian' '-mabi=lp64'
 /opt/fsl-imx-internal-xwayland/5.15-kirkstone/sysroots/x86_64-pokysdk-linux/usr/libexec/aarch64-poky-linux/gcc/aarch64-poky-linux/11.2.0/cc1 -E -quiet -v -isysroot /opt/fsl-imx-internal-xwayland/5.15-kirkstone/sysroots/armv8a-poky-linux -D _FORTIFY_SOURCE=2 - -march=armv8-a+crc+crypto -mlittle-endian -mabi=lp64 -Wformat=1 -Wformat-security -Werror=format-security -fstack-protector-strong -O2 -dumpbase -
ignoring nonexistent directory "/opt/fsl-imx-internal-xwayland/5.15-kirkstone/sysroots/armv8a-poky-linux/usr/local/include"
ignoring nonexistent directory "/opt/fsl-imx-internal-xwayland/5.15-kirkstone/sysroots/x86_64-pokysdk-linux/usr/lib/aarch64-poky-linux/gcc/aarch64-poky-linux/11.2.0/../../../../../aarch64-poky-linux/include"
#include "..." search starts here:
#include <...> search starts here:
 /opt/fsl-imx-internal-xwayland/5.15-kirkstone/sysroots/x86_64-pokysdk-linux/usr/lib/aarch64-poky-linux/gcc/aarch64-poky-linux/11.2.0/include
 /opt/fsl-imx-internal-xwayland/5.15-kirkstone/sysroots/armv8a-poky-linux/usr/lib/aarch64-poky-linux/11.2.0/include
 /opt/fsl-imx-internal-xwayland/5.15-kirkstone/sysroots/x86_64-pokysdk-linux/usr/lib/aarch64-poky-linux/gcc/aarch64-poky-linux/11.2.0/include-fixed
 /opt/fsl-imx-internal-xwayland/5.15-kirkstone/sysroots/armv8a-poky-linux/usr/include/
End of search list.
# 0 "<stdin>"
# 0 "<built-in>"
# 0 "<command-line>"
# 1 "/opt/fsl-imx-internal-xwayland/5.15-kirkstone/sysroots/armv8a-poky-linux/usr/include/stdc-predef.h" 1 3 4
# 0 "<command-line>" 2
# 1 "<stdin>"
main(){}
COMPILER_PATH=/opt/fsl-imx-internal-xwayland/5.15-kirkstone/sysroots/x86_64-pokysdk-linux/usr/libexec/aarch64-poky-linux/gcc/aarch64-poky-linux/11.2.0/:/opt/fsl-imx-internal-xwayland/5.15-kirkstone/sysroots/x86_64-pokysdk-linux/usr/libexec/aarch64-poky-linux/gcc/aarch64-poky-linux/11.2.0/:/opt/fsl-imx-internal-xwayland/5.15-kirkstone/sysroots/x86_64-pokysdk-linux/usr/libexec/aarch64-poky-linux/gcc/aarch64-poky-linux/:/opt/fsl-imx-internal-xwayland/5.15-kirkstone/sysroots/x86_64-pokysdk-linux/usr/lib/aarch64-poky-linux/gcc/aarch64-poky-linux/11.2.0/:/opt/fsl-imx-internal-xwayland/5.15-kirkstone/sysroots/x86_64-pokysdk-linux/usr/lib/aarch64-poky-linux/gcc/aarch64-poky-linux/
LIBRARY_PATH=/opt/fsl-imx-internal-xwayland/5.15-kirkstone/sysroots/x86_64-pokysdk-linux/usr/lib/aarch64-poky-linux/gcc/aarch64-poky-linux/11.2.0/:/opt/fsl-imx-internal-xwayland/5.15-kirkstone/sysroots/armv8a-poky-linux/lib/:/opt/fsl-imx-internal-xwayland/5.15-kirkstone/sysroots/armv8a-poky-linux/usr/lib/aarch64-poky-linux/11.2.0/:/opt/fsl-imx-internal-xwayland/5.15-kirkstone/sysroots/armv8a-poky-linux/usr/lib/
COLLECT_GCC_OPTIONS='-march=armv8-a+crc+crypto' '-fstack-protector-strong' '-O2' '-D' '_FORTIFY_SOURCE=2' '-Wformat=1' '-Wformat-security' '-Werror=format-security' '-E' '-v' '-mlittle-endian' '-mabi=lp64'

我发现他们都使用 aarch64-poky-linux-gcc。 但我仍然不知道它们之间的区别。

Answer 1

gcc是命令的名称。 您的 shell 将在path中查找它。

${CC}是一个变量替换。 你的 shell 会在 shell 进程的环境中寻找它。

Answer 2

gcc是您机器的编译器。 您可以像这样找到哪个和位置：

• readlink -f $(which gcc) ：这将显示您使用的程序的路径
• gcc --version ：将显示您的 gcc 编译器的版本

如果您在 PC 中构建，那么gcc将为 x86 架构构建程序。 在您的情况下，您需要一个编译器来为 arm64 架构生成程序（开源是aarch64-linux-gnu-gcc ，但提供者通常会为您提供一个修改后的工具链，其中包含编译器和所有必要的库/头文件。

当你交叉编译时，你必须“ source ”一个环境文件，这将修改终端中的环境变量如果你源环境文件这将创建环境变量CC ，这将包含编译器的路径以及编译器的一些参数.

如果您运行echo ${CC}您将看到工具链和参数。

这个想法始终是拥有一个不依赖于操作系统的隔离环境，主机 PC 的 gcc 版本，这就是为什么为您提供编译器并且您必须使用${CC}交叉编译到架构臂，这是imx SOC的基础