Checking -fPIC Failed when building the gcc 4.5.1 with --enable-plugin on cygwin

[Jeffrey Walton]

On Thu, Dec 23, 2010 at 7:09 PM, Ian Lance Taylor <iant@google.com> wrote:
> Lucky Lu <Lucky.Lu@exigenservices.com> writes:
>
>> I am having trouble with building the gcc 4.5.1 with --enable-plugin on Cygwin.
>
> As far as I know gcc plugins don't work on cygwin.
>
>> The configure string is "--enable-plugin --enable-languages=c,c++ --disable-bootstrap".
>> The error is ,
>>   checking for -rdynamic... objdump: conftest: not a dynamic object no
>>   checking for library containing dlopen... none required
>>   checking for -fPIC -shared... no
>>   configure: error:
>>   Building GCC with plugin support requires a host that supports
>>   -fPIC, -shared, -ldl and -rdynamic.
>>   make[1]: *** [configure-gcc] Error 1
>>
>> When I jump the -fPIC checking, it's success. And then failed when building a gcc plugin, print following,
>>
>>   plugin.c:1:0: warning: -fPIC ignored for target (all code is position independent)
>>   /tmp/ccU93aXF.o:plugin.c:(.text+0xd1): undefined reference to `_build3_stat'
>>   /tmp/ccU93aXF.o:plugin.c:(.text+0xff): undefined reference to `_gimple_assign_single_p'
>>   .....
>
> That's in essence because -rdynamic doesn't do anything on Windows.  It
> goes further, in that I don't know that there is any way it can be made
> to work given the way that Windows DLLs work.  There may be some way to
> make it work; I just don't know of one.
In Windows, EXEs can export symbols like DLLs. I've never used the
feature, though.

__declspec(dllexport) int g_global = 0;

int main(int argc, char* argv[])
{
    return 0;
}

>dumpbin -exports exporttest.exe
Microsoft (R) COFF/PE Dumper Version 9.00.30729.01
Copyright (C) Microsoft Corporation.  All rights reserved.

Dump of file exporttest.exe

File Type: EXECUTABLE IMAGE

  Section contains the following exports for exporttest.exe

    00000000 characteristics
    4D13EC00 time date stamp Thu Dec 23 19:40:32 2010
        0.00 version
           1 ordinal base
           1 number of functions
           1 number of names

    ordinal hint RVA      name

          1    0 00017140 ?g_global@@3HA = ?g_global@@3HA (int g_global)

  Summary

        1000 .data
        1000 .idata
        2000 .rdata
        1000 .reloc
        1000 .rsrc
        4000 .text
       10000 .textbss
>

Jeff