Message-ID: <49B94E5B.20301@gmail.com>
Date: Thu, 12 Mar 2009 18:03:07 +0000
From: Dave Korn <dave DOT korn DOT cygwin AT googlemail DOT com>
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To: Dave Korn <dave DOT korn DOT cygwin AT googlemail DOT com>
CC: cygwin AT cygwin DOT com
Subject: Re: [ANNOUNCEMENT] Updated: experimental package: gcc4-4.3.2-2
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Dave Korn wrote:

> And the immediate reason for this is the way that TSystem.o is built:
> 
> ------------------------build.log------------------------ 
> g++-4 -O2 -pipe -Wall -Woverloaded-virtual -D_DLL -Iinclude 
>          -I/usr/X11R6/include -o core/base/src/TSystem.o -c 
>          core/base/src/TSystem.cxx
> ------------------------build.log------------------------
> 
> Why is a -D for _DLL present?  That is a reserved definition in the 
> implementation's namespace, and in particular it used when compiling
> libstdc++ itself, where it alters the effect of the library headers to
> declare all the library APIs as dllexport - they are dllimport by default,
> which is what user applications want to see.
> 
> I manually re-ran the compile command without "-D_DLL" and got a good
> object file:

> So I'll now try rebuilding and retesting without _DLL defined anywhere and
> see if it solves the problem.

  Indeed it did.  With the attached patch, build and test both ran to
completion without any errors.  As far as I can see (thanks, Peter R.) the
_DLL definition conveys information from compiler to linker to tell it which
multilib variant to link against.  We have the -shared-libgcc/-static-libgcc
option in the gcc driver and the related specs to serve the same purpose on GNU.

  One disclaimer: this could have side-effects on MinGW, and should be
verified there to make sure, if it's a supported platform.  (Hopefully it'll
be equally correct there, though).

    cheers,
      DaveK


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diff -pru -x '*.o' -x '*.log' 1st.root/config/Makefile.win32gcc root/config/Makefile.win32gcc
--- 1st.root/config/Makefile.win32gcc	2009-02-26 14:07:32.000000000 +0000
+++ root/config/Makefile.win32gcc	2009-03-12 16:51:25.656250000 +0000
@@ -17,14 +17,14 @@ endif
 # Compiler:
 CXX           = g++
 CC            = gcc
-CXXFLAGS      = -pipe -Wall -Woverloaded-virtual -D_DLL $(EXTRA_CXXFLAGS) \
+CXXFLAGS      = -pipe -Wall -Woverloaded-virtual $(EXTRA_CXXFLAGS) \
                 -I/usr/X11R6/include
-CFLAGS        = -pipe -Wall -D_DLL $(EXTRA_CFLAGS) -I/usr/X11R6/include
-CINTCXXFLAGS  = -pipe -Wall -Woverloaded-virtual -D_DLL $(EXTRA_CXXFLAGS) \
+CFLAGS        = -pipe -Wall $(EXTRA_CFLAGS) -I/usr/X11R6/include
+CINTCXXFLAGS  = -pipe -Wall -Woverloaded-virtual $(EXTRA_CXXFLAGS) \
                 -DG__REGEXP -DG__UNIX -DG__SHAREDLIB \
                 -DG__OSFDLL -DG__ROOT -DG__REDIRECTIO -DG__CYGWIN \
                 -DG__NEWSTDHEADER
-CINTCFLAGS    = -pipe -Wall -D_DLL $(EXTRA_CFLAGS) \
+CINTCFLAGS    = -pipe -Wall $(EXTRA_CFLAGS) \
                 -DG__REGEXP -DG__UNIX -DG__SHAREDLIB \
                 -DG__OSFDLL -DG__ROOT -DG__REDIRECTIO -DG__CYGWIN \
                 -DG__NEWSTDHEADER
diff -pru -x '*.o' -x '*.log' 1st.root/test/Makefile.arch root/test/Makefile.arch
--- 1st.root/test/Makefile.arch	2009-02-26 14:07:26.000000000 +0000
+++ root/test/Makefile.arch	2009-03-12 16:51:16.593750000 +0000
@@ -542,7 +542,7 @@ LD            = g++
 LDFLAGS       = $(OPT) -Wl,--enable-auto-import \
                 -Wl,--enable-runtime-pseudo-reloc \
 		-L/usr/X11R6/lib
-SOFLAGS       = -shared -D_DLL -Wl,--enable-auto-image-base \
+SOFLAGS       = -shared -Wl,--enable-auto-image-base \
                 -Wl,--export-all-symbols
 EXPLLINKLIBS  = $(ROOTLIBS) $(ROOTGLIBS)
 endif


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