On Thu, 23 Dec 2010, Jeffrey Walton wrote:
On Thu, Dec 23, 2010 at 7:09 PM, Ian Lance Taylor <iant@xxxxxxxxxx> wrote:
Lucky Lu <Lucky.Lu@xxxxxxxxxxxxxxxxxx> 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
When I need to build an executable with exported symbols, I put something
like this in my makefile:
foo.exe: foo.o bar.o baz.o
ifeq ($(platform),windows)
dlltool -z $(@).def $(^)
dlltool -d $(@).def -e $(@).exp
gcc $(@).exp $(^) -o $(@)
else
gcc -rdynamic $(^) -o $(@)
endif
I've never understood why -rdynamic doesn't work on Windows. My makefiles
would certainly be prettier if it did.
