On Dec 2, 2010, at 3:05 PM, Ian Lance Taylor wrote:
> Paul Koning <paul_kon...@dell.com> writes:
>
>> On Dec 2, 2010, at 2:55 PM, Ian Lance Taylor wrote:
>>
>>> Paul Koning <paul_kon...@dell.com> writes:
>>>
>>>> I'm trying to do a cross-build of gcc 4.5.1. It works fine until I
>>>> get to libstdc++v3, where configure blows up with a message saying
>>>> "Link tests are not allowed after GCC_NO_EXECUTABLES". This happens
>>>> on the "checking for shl_load" step (line 11221 in configure).
>>>>
>>>> I looked at configure.ac to see if there were any clues. I can't tell
>>>> which line in configure.ac produces the offending line in configure
>>>> (not enough autoconf skills). In an earlier gcc (3.3.3) there was a
>>>> similar issue, and in that case I worked around it by removing
>>>> "GLIBCPP_CHECK_COMPILER_VERSION" from the configure.in file. But that
>>>> line doesn't exist in configure.ac and attempts to find something
>>>> analogous didn't get me anywhere.
>>>
>>> GCC_NO_EXECUTABLES, in config/no-executables.m4, redefines
>>> AC_LINK_IFELSE to produce that error message.
>>
>> Thanks. But why does the released configure fail like this? Any idea how
>> to fix this bug?
>
> You need to tell us precisely what you tried to do and precisely what
> happened.
>
> The TARGET/libstdc++-v3/config.log file may contain a clue.
It's configured --target=mips64el-netbsdelf --enable-languages=c,c++, on an
i686-pc-linux-gnu host.
After some searching I concocted this patch:
Index: libtool.m4
===================================================================
--- libtool.m4 (revision 147400)
+++ libtool.m4 (working copy)
@@ -1715,6 +1715,11 @@
lt_cv_dlopen_self=yes
;;
+ netbsd*)
+ lt_cv_dlopen="dlopen"
+ lt_cv_dlopen_libs=
+ ;;
+
mingw* | pw32* | cegcc*)
lt_cv_dlopen="LoadLibrary"
lt_cv_dlopen_libs=
and now I get a lot further in the libstdc++ configure, but it still doesn't
get past that. The last two steps in config.log are:
configure:56645: checking for ld version
configure:56656: result: 22001
configure:56683: checking for ld that supports -Wl,--gc-sections
configure:56686: error: Link tests are not allowed after GCC_NO_EXECUTABLES.
That's code in libstdc++-v4/acinclude.m4 . I'm not sure why it uses the ld
version number to decide that --gc-sections is supported, and then once it
finds out that it it supported, it runs another test to check if it's
supported. Can I get rid of that test link? Apparently yes:
Index: libstdc++-v3/acinclude.m4
===================================================================
--- libstdc++-v3/acinclude.m4 (revision 147400)
+++ libstdc++-v3/acinclude.m4 (working copy)
@@ -230,7 +230,8 @@
glibcxx_have_gc_sections=yes
fi
fi
- if test "$glibcxx_have_gc_sections" = "yes"; then
+ if test "$glibcxx_have_gc_sections" = "yes" &&
+ test x$gcc_no_link != xyes; then
# Sufficiently young GNU ld it is! Joy and bunny rabbits!
# NB: This flag only works reliably after 2.16.1. Configure tests
# for this are difficult, so hard wire a value that should work.
...and now the configure works, and libstdc++ is building happily.
paul
