cross gcc 与linux gcc,crosstool编译过程中gcc版本问题

crosstool编译过程中gcc版本问题

在使用crosstool构建工具链的过程中，出现了如下问题，导致arm-linux-gcc没有生成：

> checking version of gcc... 4.0.0, bad

> checking for gnumake... no

> checking for gmake... gmake

> checking version of gmake... 3.80, ok

> configure: error:

> *** These critical programs are missing or too old: gcc

> *** Check the INSTALL file for required versions.

察看crosstool目录中的contrib/inbox.txt文件，有关于这个问题的邮件描述：

> checking build system type... i686-pc-linux-gnu

> checking host system type... mipsel-unknown-linux-gnu

> checking sysdep dirs... sysdeps/mips/elf sysdeps/unix/sysv/linux/mips

> sysdeps/unix/sysv/linux sysdeps/gnu sysdeps/unix/common

> sysdeps/unix/mman sysdeps/unix/inet sysdeps/unix/sysv sysdeps/unix/mips

> sysdeps/unix sysdeps/posix sysdeps/mips/mipsel sysdeps/mips/fpu

> sysdeps/mips sysdeps/wordsize-32 sysdeps/ieee754/flt-32

> sysdeps/ieee754/dbl-64 sysdeps/ieee754 sysdeps/generic/elf sysdeps/generic

> checking for a BSD-compatible install... /usr/bin/install -c

> checking whether ln -s works... yes

> checking for pwd... /bin/pwd

> checking for mipsel-unknown-linux-gnu-gcc... gcc

> checking version of gcc... 4.0.0, bad

> checking for gnumake... no

> checking for gmake... gmake

> checking version of gmake... 3.80, ok

> configure: error:

> *** These critical programs are missing or too old: gcc

> *** Check the INSTALL file for required versions.

>

I have had the same problem. What I found was that the glibc configure

script was testing for a version of gcc 3.2.* or later. It does not test

for a major number above 3 so the test fails. I do not know where this

test is initiated, but once you have reached that point you can patch

the configure script and run demo-*.sh with the --nounpack option added

to your desired toolchain build.

This patch worked for me:

--- configure.orig      2005-09-19 21:31:45.000000000 -0400

+++ configure   2005-09-19 21:32:13.000000000 -0400

@@ -2274,6 +2274,8 @@

'') ac_prog_version="v. ?.??, bad"; ac_verc_fail=yes;;

3.[2-9]*)

ac_prog_version="$ac_prog_version, ok"; ac_verc_fail=no;;

+    4.*)

+       ac_prog_version="$ac_prog_version, ok"; ac_verc_fail=no;;

*) ac_prog_version="$ac_prog_version, bad"; ac_verc_fail=yes;;

esac

I hope that this helps. Good Luck.

-Mike Joyce

其意思就是说，在glibc的configure脚本里会检查gcc的版本，当不是需要的版本就保错, glibc的configure中有如下检查:

if test -z "$CC"; then

ac_verc_fail=yes

else

# Found it, now check the version.

echo "$as_me:$LINENO: checking version of $CC" >&5

echo $ECHO_N "checking version of $CC... $ECHO_C" >&6

ac_prog_version=`$CC -v 2>&1 | sed -n 's/^.*version \([egcygnustpi-]*[0-9.]*\).*$/\1/p'`

case $ac_prog_version in

'') ac_prog_version="v. ?.??, bad"; ac_verc_fail=yes;;

3.[2-9]*)

ac_prog_version="$ac_prog_version, ok"; ac_verc_fail=no;;

*) ac_prog_version="$ac_prog_version, bad"; ac_verc_fail=yes;;

esac

echo "$as_me:$LINENO: result: $ac_prog_version" >&5

echo "${ECHO_T}$ac_prog_version" >&6

fi

if test $ac_verc_fail = yes; then

critic_missing="$critic_missing gcc"

fi

在上面的gcc版本检查中，只使用了模式3.[2-9]*即只支持3.xxx版本的gcc，在crosstool自己的patches目录下有一个patch：patches/glibc-2.3.3-allow-gcc-4.0-configure.patch，他会在编译glic-2.3.2的时候给这个configure文件先打补丁，那个补丁来修复这个bug，但是这个补丁文件也不是很好，其内容是：

--- glibc-2.3.3/configure.old    Mon Mar 14 12:01:10 2005

+++ glibc-2.3.3/configure    Mon Mar 14 12:02:03 2005

@@ -3899,7 +3899,7 @@

ac_prog_version=`$CC -v 2>&1 | sed -n 's/^.*version \([egcygnustpi-]*[0-9.]*\).*$/\1/p'`

case $ac_prog_version in

'') ac_prog_version="v. ?.??, bad"; ac_verc_fail=yes;;

-    3.[2-9]*)

+    3.[2-9]*|4.[01]*)

ac_prog_version="$ac_prog_version, ok"; ac_verc_fail=no;;

*) ac_prog_version="$ac_prog_version, bad"; ac_verc_fail=yes;;

即，它只是增加了对4.0xxx或者4.1xxx的支持，还是不够，我现在用的是4.2.1因此还是会出错，因此，修改这个patch，改为3.[2-9]*|4.*)就可以过去了。

总之，在编译glibc的时候，其configure脚本对gcc的限定是比较严格的，而且并没有将后来的较新的版本考虑在内，这种严格的检查是我们在configure是出了错。但是如果我们直接修改glibc原码中的configure文件，又会造成crosstool在用他自己的patches给glibc的configure打补丁的时候出错，呵呵，还是去修改crosstool的补丁文件吧，glibc就留着不要动了。