[Bug target/15551] New: -mtune=pentium4 -O2 with sjlj EH breaks stack probe worker on windows32 targets

[Bug target/15551] New: -mtune=pentium4 -O2 with sjlj EH breaks stack probe worker on windows32 targets

[dannysmith at users dot sourceforge dot net]

When following testcase is compiled with

g++ -O2 -mtune=pentium4

for a cygwin or mingw target, the executable segfaults.

When tuning switch is set to pentium3 or lower,
the executable works correctly.

This is observed on 3.4.0 and on trunk, but not on gcc-3.3.3

/* pm.cpp */
/* Testcase submitted by Hans Horn to mingw bug tracker */

#include <cstring>
#include <fstream>
using namespace std;

ostream* logfile;

//char expList[20000];

int main () {

  logfile = new ofstream("bar", ios::out);

  char expList[20000];
  strcpy(expList, "foo");

  return 0;
}

/* end pm.cpp */



The problem appears to be in scheduling pass moving
sjlj exception handling insns across call to the allocate
stack probe worker (_alloca) in the function prologue.

Here is the assembler output for main() prologue from
g++ -S -O2 -mtune=pentium4 pm.cpp

_main:
	pushl	%ebp
	movl	$20092, %eax
	movl	%esp, %ebp
	pushl	%edi
	pushl	%esi
	movl	$___gxx_personality_sj0, -20052(%ebp) <<<<
	movl	$LLSDA1484, -20048(%ebp)              <<<< 
	pushl	%ebx                                     
	movl	$L4, -20040(%ebp)                     <<<< 
	call	__alloca
	movl	$16, %eax
	andl	$-16, %esp
	call	__alloca
	leal	-24(%ebp), %eax
	movl	%eax, -20044(%ebp)
	leal	-20076(%ebp), %eax
	movl	%esp, -20036(%ebp)
	movl	%eax, (%esp)
	call	__Unwind_SjLj_Register
	call	___main
<snip>

The following patch fixes by restoring the gen_blockage
barrier in i386.c:ix86_expand_prologue that was removed at revision 1.608

http://gcc.gnu.org/ml/gcc-cvs/2003-10/msg00685.html


The patch was tested on i386-pc-mingw32 on 3.4.1 and trunk.

	* config/i386/i386.c (ix86_expand_prologue):  Ensure that scheduling 
pass does
	not move insns across __alloca call


Index: i386.c
===================================================================
RCS file: /cvs/gcc/gcc/gcc/config/i386/i386.c,v
retrieving revision 1.668
diff -c -3 -p -r1.668 i386.c
*** i386.c	17 May 2004 15:23:12 -0000	1.668
--- i386.c	20 May 2004 07:30:16 -0000
*************** ix86_expand_prologue (void)
*** 5295,5300 ****
--- 5295,5304 ----
  	  rtx t = plus_constant (stack_pointer_rtx, allocate);
  	  emit_move_insn (eax, gen_rtx_MEM (SImode, t));
  	}
+ 
+       /* Ensure that scheduling pass does not move insns across __alloca
+          call.  */
+       emit_insn (gen_blockage (const0_rtx));
      }
  
    if (frame.save_regs_using_mov && !TARGET_RED_ZONE)

-- 
           Summary: -mtune=pentium4  -O2 with sjlj EH breaks stack probe
                    worker on windows32  targets
           Product: gcc
           Version: 3.4.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P2
         Component: target
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: dannysmith at users dot sourceforge dot net
                CC: gcc-bugs at gcc dot gnu dot org
 GCC build triplet: i686-pc-mingw32
  GCC host triplet: i686-pc-mingw32
GCC target triplet: i686-pc-mingw32


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=15551

[Bug target/15551] [3.4/3.5? Regression] -mtune=pentium4 -O2 with sjlj EH breaks stack probe worker on windows32 targets

[pinskia at gcc dot gnu dot org]

-- 
           What    |Removed                     |Added
----------------------------------------------------------------------------
           Keywords|                            |wrong-code
            Summary|-mtune=pentium4  -O2 with   |[3.4/3.5? Regression] -
                   |sjlj EH breaks stack probe  |mtune=pentium4  -O2 with
                   |worker on windows32  targets|sjlj EH breaks stack probe
                   |                            |worker on windows32  targets
   Target Milestone|---                         |3.4.1


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=15551

[Bug target/15551] [3.4/3.5? Regression] -mtune=pentium4 -O2 with sjlj EH breaks stack probe worker on windows32 targets

[mmitchel at gcc dot gnu dot org]

------- Additional Comments From mmitchel at gcc dot gnu dot org  2004-05-28 22:08 -------
Kelley --

It looks like your patch is causing a problem.  Would you please look into this?

-- Mark

-- 
           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |kcook at gcc dot gnu dot org


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=15551

[Bug target/15551] [3.4/3.5? Regression] -mtune=pentium4 -O2 with sjlj EH breaks stack probe worker on windows32 targets

[kcook at gcc dot gnu dot org]

------- Additional Comments From kcook at gcc dot gnu dot org  2004-06-01 20:44 -------
I'll confirm that this is a new regression and that it is also present on Cygwin.

Furthermore I'll state that though installing a blocker insn is basically a
kludge, fixing the C++ sjlj 'feature' that fooled the compiler into thinking
that it was perfectly OK to write to memory that wasn't yet allocated is not
nearly as simple nor would it be as target specific.

So I would say go for putting the kludge back :)

I'll also confirm that Danny's patch fixes the same error under Cygwin.

-- 
           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |NEW
     Ever Confirmed|                            |1
   Last reconfirmed|0000-00-00 00:00:00         |2004-06-01 20:44:27
               date|                            |


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=15551

[Bug target/15551] [3.4/3.5? Regression] -mtune=pentium4 -O2 with sjlj EH breaks stack probe worker on windows32 targets

[kcook at gcc dot gnu dot org]

------- Additional Comments From kcook at gcc dot gnu dot org  2004-06-07 20:00 -------
Created an attachment (id=6488)
 --> (http://gcc.gnu.org/bugzilla/attachment.cgi?id=6488&action=view)
A potential more correct fix

After deciphering the twisty passages.	I think this is a more correct fix. 
The problem was not really a scheduling problem, it was that the Win32 alloca
routine was marking that it clobbered memory, so gcc felt free to move stuff
above the call to __alloca.

I still need to regtest it (as that is REALLY slow on cygwin), but it survived
a c,c++ bootstrap on i686-pc-cygwin and fixed the bug (writing to unalloca
memory) as evidenced by below:

$ diff -u pm-gcc_35_orig.s pm-p4new.s
--- pm-gcc_35_orig.s	2004-06-01 14:25:47.170950500 -0400
+++ pm-p4new.s	2004-06-07 15:26:04.193903000 -0400
@@ -23,26 +23,26 @@
	movl	%esp, %ebp
	pushl	%edi
	pushl	%esi
-	movl	$___gxx_personality_sj0, -20052(%ebp)
-	movl	$LLSDA1422, -20048(%ebp)
	pushl	%ebx
-	movl	$L4, -20040(%ebp)
	call	__alloca
	movl	$16, %eax
	andl	$-16, %esp
	call	__alloca
	leal	-24(%ebp), %eax
+	movl	$___gxx_personality_sj0, -20052(%ebp)
	movl	%eax, -20044(%ebp)
	leal	-20076(%ebp), %eax
-	movl	%esp, -20036(%ebp)
+	movl	$LLSDA1422, -20048(%ebp)
	movl	%eax, (%esp)
+	movl	$L4, -20040(%ebp)
+	movl	%esp, -20036(%ebp)
	call	__Unwind_SjLj_Register
	call	___main
	movl	$256, (%esp)
	movl	$-1, -20072(%ebp)
	call	__Znwj
-	movl	%eax, -20080(%ebp)
	movl	$16, 8(%esp)
+	movl	%eax, -20080(%ebp)
	movl	$LC0, 4(%esp)
	movl	%eax, (%esp)
	movl	$1, -20072(%ebp)

This patch was against mainline, OK if it passes a complete regtest?

The patch also applies to 3.4 and I'll also regtest it there.
Mark, OK for 3.4.1 assuming that passes?

-- 
           What    |Removed                     |Added
----------------------------------------------------------------------------
         AssignedTo|unassigned at gcc dot gnu   |kcook at gcc dot gnu dot org
                   |dot org                     |
             Status|NEW                         |ASSIGNED


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=15551

[Bug target/15551] [3.4/3.5? Regression] -mtune=pentium4 -O2 with sjlj EH breaks stack probe worker on windows32 targets

[kcook at gcc dot gnu dot org]

------- Additional Comments From kcook at gcc dot gnu dot org  2004-06-10 12:47 -------
Subject: Re:  [3.4/3.5? Regression] -mtune=pentium4  -O2

I previously wrote
> The patch also applies to 3.4 and passed an all languages bootstrap; 
> I'll also regtest it there.
> 
> Mark, after a week on mainline, would this be OK for 3.4.1 assuming that 
> it also passes?
> 
> 2004-06-07  Kelley Cook  <kcook@gcc.gnu.org>
> 
> 	* config/i386/i386.c (ix86_expand_prologue): Mark win32 allocate insn
> 	as prologue.
> 	* config/i386/i386.md (allocate_stack): Clobber alloca memory.
> 	(allocate_stack_worker_postreload): Likewise.
> 	(allocate_stack_worker_rex64): Likewise.
> 	(allocate_stack_worker_rex64_postreload): Likewise.
> 	(allocate_stack_worker_1): Likewise.

For what it is worth, on both mainline and 3.4.1 this patch, under 
pentium4-pc-cygwin, created no new regressions. Moreover, it fixed one of them:

g77.f-torture/execute/labug1.f execution

OK to install?




-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=15551

[Bug target/15551] [3.4/3.5? Regression] -mtune=pentium4 -O2 with sjlj EH breaks stack probe worker on windows32 targets

[mmitchel at gcc dot gnu dot org]

------- Additional Comments From mmitchel at gcc dot gnu dot org  2004-06-10 13:43 -------
Kelley --

If this patch is approved for mainline, it's OK for 3.4.1.  Perhaps Richard
Henderson can review it for you?

-- Mark

-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=15551

[Bug target/15551] [3.4/3.5? Regression] -mtune=pentium4 -O2 with sjlj EH breaks stack probe worker on windows32 targets

[me at cgf dot cx]

------- Additional Comments From me at cgf dot cx  2004-06-15 17:42 -------
Subject: Re:  [3.4/3.5? Regression] -mtune=pentium4  -O2

On Thu, Jun 10, 2004 at 08:47:21AM -0400, Kelley Cook wrote:
>I previously wrote
>>The patch also applies to 3.4 and passed an all languages bootstrap; 
>>I'll also regtest it there.
>>
>>Mark, after a week on mainline, would this be OK for 3.4.1 assuming that 
>>it also passes?
>>
>>2004-06-07  Kelley Cook  <kcook@gcc.gnu.org>
>>
>>	* config/i386/i386.c (ix86_expand_prologue): Mark win32 allocate insn
>>	as prologue.
>>	* config/i386/i386.md (allocate_stack): Clobber alloca memory.
>>	(allocate_stack_worker_postreload): Likewise.
>>	(allocate_stack_worker_rex64): Likewise.
>>	(allocate_stack_worker_rex64_postreload): Likewise.
>>	(allocate_stack_worker_1): Likewise.
>
>For what it is worth, on both mainline and 3.4.1 this patch, under 
>pentium4-pc-cygwin, created no new regressions. Moreover, it fixed one of 
>them:
>
>g77.f-torture/execute/labug1.f execution
>
>OK to install?

This doesn't seem to have been added yet.

I think this particular problem has been kicked around quite a bit in
various incarnations.  I believe that this was code that Richard
Henderson added not so long ago.  Maybe it would be a good idea to have
him verify that it is correct?

cgf


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=15551

[Bug target/15551] [3.4/3.5? Regression] -mtune=pentium4 -O2 with sjlj EH breaks stack probe worker on windows32 targets

[mmitchel at gcc dot gnu dot org]

------- Additional Comments From mmitchel at gcc dot gnu dot org  2004-06-19 17:47 -------
Richard, there's a request for a review from you on this patch.

-- 
           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |rth at redhat dot com


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=15551

[Bug target/15551] [3.4/3.5? Regression] -mtune=pentium4 -O2 with sjlj EH breaks stack probe worker on windows32 targets

[rth at gcc dot gnu dot org]

------- Additional Comments From rth at gcc dot gnu dot org  2004-06-19 19:18 -------
The revised patch isn't correct.  The two correct changes I can think of are
(1) the gen_blockage as already written, or (2) change the alloc_stack_worker
unspec to be an unspec_volatile.

-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=15551

[Bug target/15551] [3.4/3.5? Regression] -mtune=pentium4 -O2 with sjlj EH breaks stack probe worker on windows32 targets

[rth at gcc dot gnu dot org]

------- Additional Comments From rth at gcc dot gnu dot org  2004-06-21 18:38 -------
Patch is ok.

-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=15551

[Bug target/15551] [3.4/3.5? Regression] -mtune=pentium4 -O2 with sjlj EH breaks stack probe worker on windows32 targets

[mmitchel at gcc dot gnu dot org]

------- Additional Comments From mmitchel at gcc dot gnu dot org  2004-06-21 21:26 -------
Postponed until GCC 3.4.2.

-- 
           What    |Removed                     |Added
----------------------------------------------------------------------------
   Target Milestone|3.4.1                       |3.4.2


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=15551

[Bug target/15551] [3.4/3.5? Regression] -mtune=pentium4 -O2 with sjlj EH breaks stack probe worker on windows32 targets

[cvs-commit at gcc dot gnu dot org]

------- Additional Comments From cvs-commit at gcc dot gnu dot org  2004-06-21 22:52 -------
Subject: Bug 15551

CVSROOT:	/cvs/gcc
Module name:	gcc
Changes by:	kcook@gcc.gnu.org	2004-06-21 22:52:04

Modified files:
	gcc            : ChangeLog 
	gcc/config/i386: i386.md 

Log message:
	2004-06-21  Kelley Cook  <kcook@gcc.gnu.org>
	
	PR target/15551
	* config/i386/i386.md: Change UNSPEC_STACK_PROBE to UNSPECV_STACK_PROBE.
	(allocate_stack_worker): Make unspec_volatile.
	(allocate_stack_worker_rex64):  Likewise.
	(allocate_stack_worker_postreload):  Likewise.
	(allocate_stack_worker_rex64_postreload):  Likewise.

Patches:
http://gcc.gnu.org/cgi-bin/cvsweb.cgi/gcc/gcc/ChangeLog.diff?cvsroot=gcc&r1=2.4067&r2=2.4068
http://gcc.gnu.org/cgi-bin/cvsweb.cgi/gcc/gcc/config/i386/i386.md.diff?cvsroot=gcc&r1=1.544&r2=1.545



-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=15551

[Bug target/15551] [3.4/3.5? Regression] -mtune=pentium4 -O2 with sjlj EH breaks stack probe worker on windows32 targets

[cvs-commit at gcc dot gnu dot org]

------- Additional Comments From cvs-commit at gcc dot gnu dot org  2004-06-22 21:47 -------
Subject: Bug 15551

CVSROOT:	/cvs/gcc
Module name:	gcc
Branch: 	gcc-3_4-branch
Changes by:	kcook@gcc.gnu.org	2004-06-22 21:47:47

Modified files:
	gcc            : ChangeLog 
	gcc/testsuite  : ChangeLog 
	gcc/config/i386: i386.md 
Added files:
	gcc/testsuite/g++.dg/opt: pr15551.c 

Log message:
	2004-06-22 Kelley Cook <kcook@gcc.gnu.org>
	
	PR target/15551
	* config/i386/i386.md: Change UNSPEC_STACK_PROBE to UNSPECV_STACK_PROBE.
	(allocate_stack_worker): Make unspec_volatile.
	(allocate_stack_worker_rex64):  Likewise.
	(allocate_stack_worker_postreload):  Likewise.
	(allocate_stack_worker_rex64_postreload):  Likewise.
	
	[testsuite]
	2004-06-22 Kelley Cook <kcook@gcc.gnu.org>
	
	* g++.dg/opt/pr15551.C: New testcase.

Patches:
http://gcc.gnu.org/cgi-bin/cvsweb.cgi/gcc/gcc/ChangeLog.diff?cvsroot=gcc&only_with_tag=gcc-3_4-branch&r1=2.2326.2.518&r2=2.2326.2.519
http://gcc.gnu.org/cgi-bin/cvsweb.cgi/gcc/gcc/testsuite/ChangeLog.diff?cvsroot=gcc&only_with_tag=gcc-3_4-branch&r1=1.3389.2.213&r2=1.3389.2.214
http://gcc.gnu.org/cgi-bin/cvsweb.cgi/gcc/gcc/config/i386/i386.md.diff?cvsroot=gcc&only_with_tag=gcc-3_4-branch&r1=1.502.2.4&r2=1.502.2.5
http://gcc.gnu.org/cgi-bin/cvsweb.cgi/gcc/gcc/testsuite/g++.dg/opt/pr15551.c.diff?cvsroot=gcc&only_with_tag=gcc-3_4-branch&r1=NONE&r2=1.1.2.1



-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=15551

[Bug target/15551] [3.4/3.5? Regression] -mtune=pentium4 -O2 with sjlj EH breaks stack probe worker on windows32 targets

[pinskia at gcc dot gnu dot org]

------- Additional Comments From pinskia at gcc dot gnu dot org  2004-06-22 22:16 -------
Fixed.

-- 
           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|ASSIGNED                    |RESOLVED
         Resolution|                            |FIXED
   Target Milestone|3.4.2                       |3.4.1


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=15551