Hello, Charlie. Can you please express your opinion about my request "Warning compiling pg_dump (MinGW, Windows XP)" to pgsql-hackers on Thu, 13 Jan 2011. Do you have the same warnings using MinGW environment?
You wrote: CS> I'm compiling postgresql 9.0.2 using msys + mingw + gcc 4.5.2 (latest CS> official release from mingw). This is on Windows 7 64-bit. CS> Unfortunately the built dlls, at least libpq.dll, crash if they need to CS> be relocated. This happens to me when loading libpq.dll into a project CS> that has a number of other dll requirements. Note this does NOT happen CS> when building with gcc 3.4.5. CS> Using GDB to track down the problem, the error occurs in CS> __gcc_register_frame and looks to be the same error described here: CS> http://old.nabble.com/Bad-DLL-relocation---reproducible-w--test-case-td18292380.html CS> Note a similar sounding error described, and fixed, in newer releases of CS> binutils (which mingw provides and I am using) is described here: CS> http://lists-archives.org/mingw-users/11369-error-0xc0000005-is-now-fixed.html CS> Looking at the postgresql Makefiles, the dlls are built using dllwrap. CS> In particular, see src/Makefile.shlib line 413 and src/Makefile.port CS> line 25. CS> When I change these to not use dllwrap and instead just use gcc -shared CS> the problem goes away. Therefore I'd like to propose: CS> 1. Change line 413 in src/Makefile.shlib CS> $(DLLWRAP) -o $@ --dllname $(shlib) $(DLLWRAP_FLAGS) --def CS> $(DLL_DEFFILE) $(OBJS) $(LDFLAGS) $(LDFLAGS_SL) $(SHLIB_LINK) CS> To: CS> $(CC) -shared -o $@ $(DLL_DEFFILE) $(OBJS) $(LDFLAGS) $(LDFLAGS_SL) CS> $(SHLIB_LINK) CS> 2. Changle line 73 in src/Makefile.port: CS> $(DLLWRAP) -o $@ --def $*.def $< $(LDFLAGS) $(LDFLAGS_SL) $(BE_DLLLIBS) CS> To: CS> $(CC) -shared -o $@ $*.def $< $(LDFLAGS) $(LDFLAGS_SL) $(BE_DLLLIBS) CS> I tested this by intentionally compiling libpq.dll using the link flag CS> -Wl,--image-base to make sure that its base address conflicted with CS> another dll loaded by my program. With the proposed changes, windows CS> successfully relocated libpq.dll without causing a segmentation fault. CS> I don't claim to know why dllwrap is producing dlls that can't be CS> relocated while gcc -shared is. But it appears to have been deprecated CS> back in 2006 according to the binutils mailing list: CS> http://www.mail-archive.com/bug-binutils@gnu.org/msg01470.html CS> So between being deprecated and not producing relocatable dlls, it seems CS> like its best to stop using dllwrap. If this seems like a reasonable CS> change I can put together a quick patch if that helps. CS> Thanks, CS> Charlie -- With best wishes, Pavel mailto:pa...@gf.microolap.com -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
