为CentOS7编译升级GCC

CentOS7默认的GCC版本是４.８，不支持C++14，对C++11支持也不完善，编译时需要加上-std=c++11才能勉强支持C++11，所以对GCC来个升级。

因为3.10的内核实在太老，加之GCC4.8和最新的GCC8.2代差太大，直接用GCC4.8编译安装GCC7或8是不能成功的，我选择了GCC6.5，6.5对C++11支持很完美，还支持C++14.

• 1、下载和解压源码

这里列出了GCC主要的几个镜像站，很遗憾亚洲只有日本一个，国内一个都没有

https://gcc.gnu.org/mirrors.html

GCC mirror sites

Our releases are available on the GNU FTP server and its mirrors. The following sites mirror the gcc.gnu.org FTP site (Phoenix, Arizona, USA) directly:

• France (no snapshots): ftp.lip6.fr, thanks to ftpmaint at lip6.fr
• France, Brittany: ftp.irisa.fr, thanks to ftpmaint at irisa.fr
• France, Versailles: ftp.uvsq.fr, thanks to ftpmaint at uvsq.fr
• Germany, Berlin: ftp.fu-berlin.de, thanks to ftp at fu-berlin.de
• Germany: ftp.gwdg.de, thanks to emoenke at gwdg.de
• Germany: ftp.mpi-sb.mpg.de, thanks to ftpadmin at mpi-sb.mpg.de
• Germany: http://gcc.cybermirror.org, thanks to Sascha Schwarz (cm at cybermirror.org)
• Greece: ftp.ntua.gr, thanks to ftpadm at ntua.gr
• Hungary, Budapest: robotlab.itk.ppke.hu, thanks to Adam Rak (neurhlp at gmail.com)
• Japan: ftp.tsukuba.wide.ad.jp, thanks to Kohei Takahashi (tsukuba-ftp-servers at tsukuba.wide.ad.jp)
• The Netherlands, Dronten:   http://mirror.koddos.net/gcc/ |   rsync://mirror.koddos.net/gcc/,   thanks to Martin ([email protected]) at KoDDoS.
• The Netherlands, Nijmegen: ftp.nluug.nl, thanks to Jan Cristiaan van Winkel (jc at ATComputing.nl)
• Russia, Novosibirsk: http://mirror.linux-ia64.org/gnu/gcc/, thanks to Daniel Volchixin
• Slovakia, Bratislava: gcc.fyxm.net, thanks to Jan Teluch (admin at 2600.sk)
• UK: ftp://ftp.mirrorservice.org/sites/sourceware.org/pub/gcc/, thanks to mirror at mirrorservice.org
• US, San Francisco: https://bigsearcher.com/mirrors/gcc/, thanks to [email protected]
• US, San Jose: http://www.netgull.com, thanks to admin at netgull.com
• US: http://mirrors-usa.go-parts.com/gcc, thanks to Dan Derebenskiy
• US, Michigan: http://mirrors.concertpass.com/gcc/, thanks to [email protected].

以我的经验，旧金山和圣何塞的镜像站最快，国内中科大和清华也可以下载，不过md5检验值与上面镜像站不一致，还是乖乖的从上面下载吧，或许这就是为什么上面没有列出科大源或者清华源的原因吧。

下面以旧金山镜像为例

wget https://bigsearcher.com/mirrors/gcc/releases/gcc-6.5.0/gcc-6.5.0.tar.gz

解压和下载依赖项，在解压之后的源码目录contrib下有一个名为download_prerequisites的文件，运行它可以直接下载mpfr之类的东西，这就是考验耐心的时候了，国内下载速度超慢！

$./contrib/download_prerequisites

不过你可以修改一下上面这个脚本，把默认的ftp://gcc.gnu.org替换成其它的镜像链接，比如圣何塞的镜像就很快，速度大概140KB/s，这已经是最快的了

#! /bin/sh

# Download some prerequisites needed by gcc.
# Run this from the top level of the gcc source tree and the gcc
# build will do the right thing.
#
# (C) 2010 Free Software Foundation
#
# This program is free software: you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.
# 
# This program is distributed in the hope that it will be useful, but
# WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
# General Public License for more details.
# 
# You should have received a copy of the GNU General Public License
# along with this program. If not, see http://www.gnu.org/licenses/.

# If you want to disable Graphite loop optimizations while building GCC,
# DO NOT set GRAPHITE_LOOP_OPT as yes so that the isl package will not
# be downloaded.
GRAPHITE_LOOP_OPT=yes

if [ ! -e gcc/BASE-VER ] ; then
	echo "You must run this script in the top level GCC source directory."
	exit 1
fi

# Necessary to build GCC.
MPFR=mpfr-2.4.2
GMP=gmp-4.3.2
MPC=mpc-0.8.1

wget ftp://gcc.gnu.org/pub/gcc/infrastructure/$MPFR.tar.bz2 || exit 1
tar xjf $MPFR.tar.bz2 || exit 1
ln -sf $MPFR mpfr || exit 1

wget ftp://gcc.gnu.org/pub/gcc/infrastructure/$GMP.tar.bz2 || exit 1
tar xjf $GMP.tar.bz2  || exit 1
ln -sf $GMP gmp || exit 1

wget ftp://gcc.gnu.org/pub/gcc/infrastructure/$MPC.tar.gz || exit 1
tar xzf $MPC.tar.gz || exit 1
ln -sf $MPC mpc || exit 1

# Necessary to build GCC with the Graphite loop optimizations.
if [ "$GRAPHITE_LOOP_OPT" = "yes" ] ; then
  ISL=isl-0.15

  wget ftp://gcc.gnu.org/pub/gcc/infrastructure/$ISL.tar.bz2 || exit 1
  tar xjf $ISL.tar.bz2  || exit 1
  # Fix trailing comma which errors with -pedantic for host GCC <= 4.3
  sed -e 's/isl_stat_ok = 0,/isl_stat_ok = 0/' isl-0.15/include/isl/ctx.h > isl-0.15/include/isl/ctx.h.tem && mv isl-0.15/include/isl/ctx.h.tem isl-0.15/include/isl/ctx.h
  ln -sf $ISL isl || exit 1
fi

如果是歪果的云主机不用修改，速度也很快

$ ./contrib/download_prerequisites 
--2018-12-30 02:43:45--  ftp://gcc.gnu.org/pub/gcc/infrastructure/mpfr-2.4.2.tar.bz2
           => ‘mpfr-2.4.2.tar.bz2.1’
Resolving gcc.gnu.org (gcc.gnu.org)... 209.132.180.131
Connecting to gcc.gnu.org (gcc.gnu.org)|209.132.180.131|:21... connected.
Logging in as anonymous ... Logged in!
==> SYST ... done.    ==> PWD ... done.
==> TYPE I ... done.  ==> CWD (1) /pub/gcc/infrastructure ... done.
==> SIZE mpfr-2.4.2.tar.bz2 ... 1077886
==> PASV ... done.    ==> RETR mpfr-2.4.2.tar.bz2 ... done.
Length: 1077886 (1.0M) (unauthoritative)

100%[====================================================================================>] 1,077,886   5.08MB/s   in 0.2s   

2018-12-30 02:43:46 (5.08 MB/s) - ‘mpfr-2.4.2.tar.bz2.1’ saved [1077886]

--2018-12-30 02:43:46--  ftp://gcc.gnu.org/pub/gcc/infrastructure/gmp-4.3.2.tar.bz2
           => ‘gmp-4.3.2.tar.bz2’
Resolving gcc.gnu.org (gcc.gnu.org)... 209.132.180.131
Connecting to gcc.gnu.org (gcc.gnu.org)|209.132.180.131|:21... connected.
Logging in as anonymous ... Logged in!
==> SYST ... done.    ==> PWD ... done.
==> TYPE I ... done.  ==> CWD (1) /pub/gcc/infrastructure ... done.
==> SIZE gmp-4.3.2.tar.bz2 ... 1897483
==> PASV ... done.    ==> RETR gmp-4.3.2.tar.bz2 ... done.
Length: 1897483 (1.8M) (unauthoritative)

100%[====================================================================================>] 1,897,483   7.37MB/s   in 0.2s   

2018-12-30 02:43:46 (7.37 MB/s) - ‘gmp-4.3.2.tar.bz2’ saved [1897483]

--2018-12-30 02:43:47--  ftp://gcc.gnu.org/pub/gcc/infrastructure/mpc-0.8.1.tar.gz
           => ‘mpc-0.8.1.tar.gz’
Resolving gcc.gnu.org (gcc.gnu.org)... 209.132.180.131
Connecting to gcc.gnu.org (gcc.gnu.org)|209.132.180.131|:21... connected.
Logging in as anonymous ... Logged in!
==> SYST ... done.    ==> PWD ... done.
==> TYPE I ... done.  ==> CWD (1) /pub/gcc/infrastructure ... done.
==> SIZE mpc-0.8.1.tar.gz ... 544950
==> PASV ... done.    ==> RETR mpc-0.8.1.tar.gz ... done.
Length: 544950 (532K) (unauthoritative)

100%[====================================================================================>] 544,950     --.-K/s   in 0.1s    

2018-12-30 02:43:48 (3.55 MB/s) - ‘mpc-0.8.1.tar.gz’ saved [544950]

--2018-12-30 02:43:48--  ftp://gcc.gnu.org/pub/gcc/infrastructure/isl-0.15.tar.bz2
           => ‘isl-0.15.tar.bz2’
Resolving gcc.gnu.org (gcc.gnu.org)... 209.132.180.131
Connecting to gcc.gnu.org (gcc.gnu.org)|209.132.180.131|:21... connected.
Logging in as anonymous ... Logged in!
==> SYST ... done.    ==> PWD ... done.
==> TYPE I ... done.  ==> CWD (1) /pub/gcc/infrastructure ... done.
==> SIZE isl-0.15.tar.bz2 ... 1574964
==> PASV ... done.    ==> RETR isl-0.15.tar.bz2 ... done.
Length: 1574964 (1.5M) (unauthoritative)

100%[====================================================================================>] 1,574,964   6.25MB/s   in 0.2s   

2018-12-30 02:43:48 (6.25 MB/s) - ‘isl-0.15.tar.bz2’ saved [1574964]

• 2、编译

configure参数可以在现有的GCC上修改，这是系统自带的GCC configure信息

$ gcc -v
Using built-in specs.
COLLECT_GCC=gcc
COLLECT_LTO_WRAPPER=/usr/libexec/gcc/x86_64-redhat-linux/4.8.5/lto-wrapper
Target: x86_64-redhat-linux
Configured with: ../configure --prefix=/usr --mandir=/usr/share/man --infodir=/usr/share/info --with-bugurl=http://bugzilla.redhat.com/bugzilla --enable-bootstrap --enable-shared --enable-threads=posix --enable-checking=release --with-system-zlib --enable-__cxa_atexit --disable-libunwind-exceptions --enable-gnu-unique-object --enable-linker-build-id --with-linker-hash-style=gnu --enable-languages=c,c++,objc,obj-c++,java,fortran,ada,go,lto --enable-plugin --enable-initfini-array --disable-libgcj --with-isl=/builddir/build/BUILD/gcc-4.8.5-20150702/obj-x86_64-redhat-linux/isl-install --with-cloog=/builddir/build/BUILD/gcc-4.8.5-20150702/obj-x86_64-redhat-linux/cloog-install --enable-gnu-indirect-function --with-tune=generic --with-arch_32=x86-64 --build=x86_64-redhat-linux
Thread model: posix
gcc version 4.8.5 20150623 (Red Hat 4.8.5-36) (GCC)

把不需要的信息删掉，比如objc,obj-c++,java,fortran,ada,go,lto都不要，只要C和C++，bugurl也不需要，如果需要multilib，还要安装32位的glibc、libstdc++以及zlib

这是我的一个配置

$ gcc -v
Using built-in specs.
COLLECT_GCC=gcc
COLLECT_LTO_WRAPPER=/usr/libexec/gcc/x86_64-redhat-linux/6.5.0/lto-wrapper
Target: x86_64-redhat-linux
Configured with: ../configure --enable-bootstrap --enable-languages=c,c++,objc,obj-c++ --prefix=/usr --mandir=/usr/share/man --infodir=/usr/share/info --enable-shared --enable-threads=posix --enable-checking=release --enable-multilib --with-system-zlib --enable-__cxa_atexit --disable-libunwind-exceptions --enable-gnu-unique-object --enable-linker-build-id --with-gcc-major-version-only --with-linker-hash-style=gnu --enable-plugin --enable-initfini-array --with-isl --enable-libmpx --enable-offload-targets=nvptx-none --without-cuda-driver --enable-gnu-indirect-function --enable-cet --with-tune=generic --with-arch_32=i686 --build=x86_64-redhat-linux
Thread model: posix
gcc version 6.5.0 (GCC)

在源码目录下新建一个文件夹用于存放编译生成的临时文件

$mkdir build

然后开始

$../configure --enable-bootstrap --enable-languages=c,c++,objc,obj-c++ --prefix=/usr --mandir=/usr/share/man --infodir=/usr/share/info --enable-shared --enable-threads=posix --enable-checking=release --enable-multilib --with-system-zlib --enable-__cxa_atexit --disable-libunwind-exceptions --enable-gnu-unique-object --enable-linker-build-id --with-gcc-major-version-only --with-linker-hash-style=gnu --enable-plugin --enable-initfini-array --with-isl --enable-libmpx --enable-offload-targets=nvptx-none --without-cuda-driver --enable-gnu-indirect-function --enable-cet --with-tune=generic --with-arch_32=i686 --build=x86_64-redhat-linux

上面的configure没错误的话，

$make

make时可以开启多线程，make结束之后，最好先卸载现有的gcc和gcc-c++再安装新版gcc

$make install

3、检验是否安装正确

$gcc -v

$g++ -v

都能输出version信息基本就没问题

为了保险起见，最好试着编译一个64位和32位的程序

4、常见错误及解决办法

（1）缺失32位Lib，但configure使能了multilib

/usr/bin/ld: cannot find crt1.o: No such file or directory
/usr/bin/ld: cannot find crti.o: No such file or directory
/usr/bin/ld: cannot find -lc
/usr/bin/ld: cannot find crtn.o: No such file or directory
collect2: error: ld returned 1 exit status
configure: error: I suspect your system does not have 32-bit development libraries (libc and headers). If you have them, rerun configure with --enable-multilib. If you do not have them, and want to build a 64-bit-only compiler, rerun configure with --disable-multilib.
解决：安装对应的32位lib

（2）configure: error: in `/home/nereus/downloads/gcc-src/build/gcc':

checking how to run the C++ preprocessor... /lib/cpp
configure: error: in `/home/nereus/downloads/gcc-src/build/gcc':
configure: error: C++ preprocessor "/lib/cpp" fails sanity check
See `config.log' for more details.
解决：

缺失glibc-headers或g++

CentOS安装

$yum install glibc-headers
$yum install gcc-c++

Debian安装

$apt-get install build-essential 
$apt-get install g++

（3）configure: error: changes in the environment can compromise the build

configure: error: changes in the environment can compromise the build
configure: error: run `make distclean' and/or `rm ./config.cache' and start over
make[2]: *** [configure-stage1-gmp] Error 1
make[2]: Leaving directory `/home/nereus/downloads/gcc-src/build'
make[1]: *** [stage1-bubble] Error 2
make[1]: Leaving directory `/home/nereus/downloads/gcc-src/build'
make: *** [all] Error 2
解决方法：上面已经给出了run `make distclean' and/or `rm ./config.cache' and start over