Date: Mon, 14 Apr 2003 17:42:09 -0500 (CDT) From: Loren James Rittle <rittle@latour.rsch.comm.mot.com> To: hackers@freebsd.org Subject: Re: gcc iussue or ... ? Message-ID: <200304142242.h3EMg9d8056897@latour.rsch.comm.mot.com> In-Reply-To: <20030413124626.5e782421.kabaev@bellatlantic.net> (message from Alexander Kabaev on Sun, 13 Apr 2003 12:46:26 -0400) References: <5.2.0.9.2.20030411082040.02604e90@194.184.65.4> <200304120241.h3C2fQCc061882@latour.rsch.comm.mot.com> <20030413012636.GA76030@dragon.nuxi.com> <20030413124626.5e782421.kabaev@bellatlantic.net>
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In article <20030413124626.5e782421.kabaev@bellatlantic.net>,
Alexander Kabaev<kabaev@bellatlantic.net> writes:
> On Sat, 12 Apr 2003 18:26:36 -0700
> "David O'Brien" <obrien@freebsd.org> wrote:
>> I'm not sure we should change FreeBSD to do something that purposfully
>> produces wrong semantics. [...]
> I think there is a slight confusion here. It is -fconserve-space flag
> what introduces wrong semantics, [...]
Agreed (with Alex). David, for the record: Here is the short test
which displays the exact change:
; cat >t.C
int t;
<EOF>
; /usr/bin/g++ -c t.C # gcc 2.95.4 20020320 [FreeBSD]
; size t.o
text data bss dec hex filename
0 4 0 4 4 t.o
; /usr/local/beta-gcc/bin/g++ -c t.C # FSF mainline
; size t.o
text data bss dec hex filename
0 0 4 4 4 t.o
This is OK since there is no concept of "common merging" in C++. At
one point, I knew the reason why older g++ assigned no data to BSS.
Either way, this was a purposeful change in g++ (I can't cite the
thread off-hand but I read it at the time). The system compiler on
ref5/beast is doing section assignment for C++ the "new way".
David, I do think that you found a section of code (which was
originally written in 1996 before g++ used BSS) that could be
tightened up in light of the new section rules used by g++. Anyone
willing to post the patch ``attn: Mark Mitchell/Jason Merrill'' to
gcc-patches? Tree munging is outside my area of expertise.
Regards,
Loren
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