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* [Bug c++/32281] New: A problem of gcc4.1.0(O3 optimize)
@ 2007-06-11 3:38 stillzhang at tencent dot com
2007-06-11 3:41 ` [Bug c++/32281] " pinskia at gcc dot gnu dot org
` (3 more replies)
0 siblings, 4 replies; 5+ messages in thread
From: stillzhang at tencent dot com @ 2007-06-11 3:38 UTC (permalink / raw)
To: gcc-bugs
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When I user gcc4.1.0 to compile mysql4.1.22, I find some errors. I¡¯m not sure
whether it¡¯s a gcc bug or not, so I need your help.
The version of gcc:
gcc -v
Using built-in specs.
Target: i586-suse-linux
Configured with: ../configure --enable-threads=posix --prefix=/usr
--with-local-prefix=/usr/local --infodir=/usr/share/info
--mandir=/usr/share/man --libdir=/usr/lib --libexecdir=/usr/lib
--enable-languages=c,c++,objc,fortran,java,ada --enable-checking=release
--with-gxx-include-dir=/usr/include/c++/4.1.0 --enable-ssp --disable-libssp
--enable-java-awt=gtk --enable-gtk-cairo --disable-libjava-multilib
--with-slibdir=/lib --with-system-zlib --enable-shared --enable-__cxa_atexit
--enable-libstdcxx-allocator=new --without-system-libunwind --with-cpu=generic
--host=i586-suse-linux
Thread model: posix
gcc version 4.1.0 (SUSE Linux)
Linux verson:
Linux 2.6.16.21-0.8-TENCENT #1 SMP Sat Jan 13 19:17:08 CST 2007 i686 i686 i386
GNU/Linux
Mysql4.1.22 is from http://mysql.he.net/Downloads/MySQL-4.1/mysql-4.1.22.tar.gz
.
The error is in function mysql_stmt_execute(THD *thd, char *packet, uint
packet_length)( mysql-4.1.22/sql/sql_prepare.cc:1786).
The file is complied by these arguments:
g++ -DMYSQL_SERVER -DDEFAULT_MYSQL_HOME="\"/data/home/c4b/still/bin/mysql/\""
-DDATADIR="\"/data/home/c4b/still/bin/mysql//var\""
-DSHAREDIR="\"/data/home/c4b/still/bin/mysql//share/mysql\"" -DHAVE_CONFIG_H
-I. -I. -I.. -I../innobase/include -I../include -I../include -I../regex -I.
-O3 -DDBUG_OFF -fno-implicit-templates -fno-exceptions -fno-rtti -MT
sql_prepare.o -MD -MP -MF ".deps/sql_prepare.Tpo" -g -c -o sql_prepare.o
sql_prepare.cc
In line 1822-1824
1822 if (setup_conversion_functions(stmt, (uchar **) &packet, packet_end) ||
1823 stmt->set_params(stmt, null_array, (uchar *) packet,
packet_end,
1824 &expanded_query))
And the function ¡°setup_conversion_functions¡± is compiled as inline function.
The lase sentence of in function setup_conversion_functions is *data= read_pos;
The three sentences is compiled to
0x08197bff <_Z18mysql_stmt_executeP3THDPcj+703>: mov 0xc(%ebp),%ecx
0x08197c02 <_Z18mysql_stmt_executeP3THDPcj+706>: mov
0xffffffc0(%ebp),%ebx
0x08197c05 <_Z18mysql_stmt_executeP3THDPcj+709>: mov
0xffffffb4(%ebp),%eax
0x08197c08 <_Z18mysql_stmt_executeP3THDPcj+712>: mov %ecx,0x8(%esp)
0x08197c0c <_Z18mysql_stmt_executeP3THDPcj+716>: mov
0xffffffd0(%ebp),%edx
0x08197c0f <_Z18mysql_stmt_executeP3THDPcj+719>: mov
0xffffffb8(%ebp),%ecx
0x08197c12 <_Z18mysql_stmt_executeP3THDPcj+722>: mov %ebx,0xc(%ebp)
//*data= read_pos
0x08197c15 <_Z18mysql_stmt_executeP3THDPcj+725>: lea
0xffffffdc(%ebp),%ebx
0x08197c18 <_Z18mysql_stmt_executeP3THDPcj+728>: mov %ebx,0x10(%esp)
0x08197c1c <_Z18mysql_stmt_executeP3THDPcj+732>: mov %eax,0xc(%esp)
0x08197c20 <_Z18mysql_stmt_executeP3THDPcj+736>: mov %edx,0x4(%esp)
0x08197c24 <_Z18mysql_stmt_executeP3THDPcj+740>: mov %ecx,(%esp)
0x08197c27 <_Z18mysql_stmt_executeP3THDPcj+743>: call *0x764(%ecx)
0xc(%ebp) is the address of &packet(in function mysql_stmt_execute) and also
the address of *data(in function setup_conversion_functions).
In 703 and 712, we can see the value of 0xc(%ebp) is push to stack for the
third argument of function stmt->set_params.
The sentence 722 is for *data= read_pos, Move the read_pos to *data(address
0xc(%ebp)).
So the third argument of function stmt->set_params use the old value not the
new value.
Am I right£¿Wait for your reply, and thank you very much.
Best wishes,
Still
--
Summary: A problem of gcc4.1.0(O3 optimize)
Product: gcc
Version: 4.1.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c++
AssignedTo: unassigned at gcc dot gnu dot org
ReportedBy: stillzhang at tencent dot com
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=32281
^ permalink raw reply [flat|nested] 5+ messages in thread
* [Bug c++/32281] A problem of gcc4.1.0(O3 optimize)
2007-06-11 3:38 [Bug c++/32281] New: A problem of gcc4.1.0(O3 optimize) stillzhang at tencent dot com
@ 2007-06-11 3:41 ` pinskia at gcc dot gnu dot org
2007-06-11 6:07 ` stillzhang at tencent dot com
` (2 subsequent siblings)
3 siblings, 0 replies; 5+ messages in thread
From: pinskia at gcc dot gnu dot org @ 2007-06-11 3:41 UTC (permalink / raw)
To: gcc-bugs
------- Comment #1 from pinskia at gcc dot gnu dot org 2007-06-11 03:41 -------
So packet is char*, and you are accessing it as uchar*, so this code is
violating C/C++ aliasing rules.
*** This bug has been marked as a duplicate of 21920 ***
--
pinskia at gcc dot gnu dot org changed:
What |Removed |Added
----------------------------------------------------------------------------
Status|UNCONFIRMED |RESOLVED
Resolution| |DUPLICATE
Summary|A problem of gcc4.1.0(O3 |A problem of gcc4.1.0(O3
|optimize) |optimize)
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=32281
^ permalink raw reply [flat|nested] 5+ messages in thread
* [Bug c++/32281] A problem of gcc4.1.0(O3 optimize)
2007-06-11 3:38 [Bug c++/32281] New: A problem of gcc4.1.0(O3 optimize) stillzhang at tencent dot com
2007-06-11 3:41 ` [Bug c++/32281] " pinskia at gcc dot gnu dot org
@ 2007-06-11 6:07 ` stillzhang at tencent dot com
2007-06-11 7:12 ` stillzhang at tencent dot com
2007-06-11 12:23 ` rguenth at gcc dot gnu dot org
3 siblings, 0 replies; 5+ messages in thread
From: stillzhang at tencent dot com @ 2007-06-11 6:07 UTC (permalink / raw)
To: gcc-bugs
------- Comment #2 from stillzhang at tencent dot com 2007-06-11 06:07 -------
Thank you.
But if i compiled it without -O3, it work fine.
If I compiled it under gcc3.3 with -O3, it also work fine.
The same program with different optimize has different, so i think it should
not be like this.
--
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=32281
^ permalink raw reply [flat|nested] 5+ messages in thread
* [Bug c++/32281] A problem of gcc4.1.0(O3 optimize)
2007-06-11 3:38 [Bug c++/32281] New: A problem of gcc4.1.0(O3 optimize) stillzhang at tencent dot com
2007-06-11 3:41 ` [Bug c++/32281] " pinskia at gcc dot gnu dot org
2007-06-11 6:07 ` stillzhang at tencent dot com
@ 2007-06-11 7:12 ` stillzhang at tencent dot com
2007-06-11 12:23 ` rguenth at gcc dot gnu dot org
3 siblings, 0 replies; 5+ messages in thread
From: stillzhang at tencent dot com @ 2007-06-11 7:12 UTC (permalink / raw)
To: gcc-bugs
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------- Comment #3 from stillzhang at tencent dot com 2007-06-11 07:11 -------
I think if "&packet" should be changed, it should change before the function
¡°stmt->set_params¡±. And in fact it is changed after "stmt->set_params¡±, so I
think it's a logical error.
Best wishes,
still
--
stillzhang at tencent dot com changed:
What |Removed |Added
----------------------------------------------------------------------------
Status|RESOLVED |UNCONFIRMED
Resolution|DUPLICATE |
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=32281
^ permalink raw reply [flat|nested] 5+ messages in thread
* [Bug c++/32281] A problem of gcc4.1.0(O3 optimize)
2007-06-11 3:38 [Bug c++/32281] New: A problem of gcc4.1.0(O3 optimize) stillzhang at tencent dot com
` (2 preceding siblings ...)
2007-06-11 7:12 ` stillzhang at tencent dot com
@ 2007-06-11 12:23 ` rguenth at gcc dot gnu dot org
3 siblings, 0 replies; 5+ messages in thread
From: rguenth at gcc dot gnu dot org @ 2007-06-11 12:23 UTC (permalink / raw)
To: gcc-bugs
------- Comment #4 from rguenth at gcc dot gnu dot org 2007-06-11 12:23 -------
It is still violating aliasing rules. That only -O3 fails is because -O3
enables
-finline-functions, so it should as well fail with lower optimization settings
with -finline-functions. Also -fno-strict-aliasing will fix it.
*** This bug has been marked as a duplicate of 21920 ***
--
rguenth at gcc dot gnu dot org changed:
What |Removed |Added
----------------------------------------------------------------------------
Status|UNCONFIRMED |RESOLVED
Resolution| |DUPLICATE
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=32281
^ permalink raw reply [flat|nested] 5+ messages in thread
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2007-06-11 3:38 [Bug c++/32281] New: A problem of gcc4.1.0(O3 optimize) stillzhang at tencent dot com
2007-06-11 3:41 ` [Bug c++/32281] " pinskia at gcc dot gnu dot org
2007-06-11 6:07 ` stillzhang at tencent dot com
2007-06-11 7:12 ` stillzhang at tencent dot com
2007-06-11 12:23 ` rguenth at gcc dot gnu dot org
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