[Bug ada/26983] New: Missing label in a nested function

[Bug ada/26983] New: Missing label in a nested function

[hebisch at math dot uni dot wroc dot pl]

The following program:

void
Object (void)
{
void * jmpbuf_1[6];
void P (void)
{
  {
    void * jmpbuf_3[6];

    if (__builtin_setjmp (&jmpbuf_3)) goto nonlocal_exit_2; else (void) 0;;
    __builtin_longjmp (&jmpbuf_1, 1);
    nonlocal_exit_2:;;
  }
}
  {
    if (__builtin_setjmp (&jmpbuf_1)) goto nonlocal_exit_0; else (void) 0;;
    P ();
    nonlocal_exit_0:;;
  }
}

int
main(void)
{
  Object ();
}

gives me:
../gcc-lin/prev-gcc/xgcc -B../gcc-lin/prev-gcc
mjmp2.c/tmp/cc06O64A.o(.text+0x5a): In function `P.1525':
: undefined reference to `.L8'
collect2: ld returned 1 exit status

Using gcc-4.2-20060401. The problem also shows up with gcc-4.0.2 and
gcc-4.1.0 on amd64. Also the problem shows in the output of a
cross-compiler targetting powerpc-apple-darwin7. The original problem
was discovered in GNU Pascal on powerpc-apple-darwin7 and the program
above tries to reproduce Pascal problem. The program compiles using
gcc-3.4.4.


-- 
           Summary: Missing label in a nested function
           Product: gcc
           Version: unknown
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: ada
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: hebisch at math dot uni dot wroc dot pl
 GCC build triplet: i686-pc-linux-gnu
  GCC host triplet: i686-pc-linux-gnu
GCC target triplet: i686-pc-linux-gnu


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=26983

[Bug middle-end/26983] Missing label in a nested function with builtin_setjmp/longjmp

[pinskia at gcc dot gnu dot org]

------- Comment #1 from pinskia at gcc dot gnu dot org  2006-04-02 08:59 -------
Confirmed.


-- 

pinskia at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |NEW
     Ever Confirmed|0                           |1
           Keywords|                            |assemble-failure, link-
                   |                            |failure
   Last reconfirmed|0000-00-00 00:00:00         |2006-04-02 08:59:40
               date|                            |
            Summary|Missing label in a nested   |Missing label in a nested
                   |function                    |function with
                   |                            |builtin_setjmp/longjmp


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=26983

[Bug middle-end/26983] [4.0/4.1/4.2 Regression] Missing label in a nested function with builtin_setjmp/longjmp

[pinskia at gcc dot gnu dot org]

-- 

pinskia at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
      Known to fail|                            |4.0.2 4.1.0 4.2.0
      Known to work|                            |3.4.4
            Summary|Missing label in a nested   |[4.0/4.1/4.2 Regression]
                   |function with               |Missing label in a nested
                   |builtin_setjmp/longjmp      |function with
                   |                            |builtin_setjmp/longjmp
   Target Milestone|---                         |4.0.4
            Version|unknown                     |4.1.0


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=26983

[Bug middle-end/26983] [4.0/4.1/4.2 Regression] Missing label in a nested function with builtin_setjmp/longjmp

[mmitchel at gcc dot gnu dot org]

-- 

mmitchel at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
           Priority|P3                          |P1


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=26983

[Bug middle-end/26983] [4.0/4.1/4.2 Regression] Missing label in a nested function with builtin_setjmp/longjmp

[steven at gcc dot gnu dot org]

------- Comment #2 from steven at gcc dot gnu dot org  2006-06-11 08:55 -------
I can't reproduce this with ToT.


-- 

steven at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|NEW                         |WAITING


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=26983

[Bug middle-end/26983] [4.0/4.1/4.2 Regression] Missing label in a nested function with builtin_setjmp/longjmp

[pinskia at gcc dot gnu dot org]

------- Comment #3 from pinskia at gcc dot gnu dot org  2006-06-11 13:35 -------
Still reproducible on powerpc-darwin with 4.2.0 20060608.


-- 

pinskia at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|WAITING                     |NEW
   Last reconfirmed|2006-04-02 08:59:40         |2006-06-11 13:35:04
               date|                            |


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=26983

[Bug middle-end/26983] [4.0/4.1/4.2 Regression] Missing label in a nested function with builtin_setjmp/longjmp

[steven at gcc dot gnu dot org]

------- Comment #4 from steven at gcc dot gnu dot org  2006-07-25 22:52 -------
In the .104.expand dump we have:

(insn 10 9 11 3 (set (reg/f:SI 63)
        (label_ref:SI 16)) -1 (nil)
    (insn_list:REG_LABEL 16 (nil)))

and

;; Start of basic block 4, registers live: (nil)
(code_label 16 15 52 4 8 "" [1 uses])


But in the .105.sibling dump, we have already lost the label and in fact the
entire basic block 4.  Apparently gcc decides that the block is unreachable...?


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=26983

[Bug middle-end/26983] [4.0/4.1/4.2 Regression] Missing label with builtin_setjmp/longjmp

[reichelt at gcc dot gnu dot org]

------- Comment #5 from reichelt at gcc dot gnu dot org  2006-07-27 13:00 -------
Here's a reduced testcase without nested functions:

====================================
void* jmpbuf[6];

void foo()
{
    __builtin_setjmp (jmpbuf);
}

int main()
{
    return 0;
}
====================================


-- 

reichelt at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |reichelt at gcc dot gnu dot
                   |                            |org
           Keywords|                            |monitored
            Summary|[4.0/4.1/4.2 Regression]    |[4.0/4.1/4.2 Regression]
                   |Missing label in a nested   |Missing label with
                   |function with               |builtin_setjmp/longjmp
                   |builtin_setjmp/longjmp      |


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=26983

[Bug middle-end/26983] [4.0/4.1/4.2 Regression] Missing label with builtin_setjmp/longjmp

[steven at gcc dot gnu dot org]

------- Comment #6 from steven at gcc dot gnu dot org  2006-07-27 13:25 -------
Thanks Volkert.  I had a test case like that, I should have put it in this
audit trail.

I am *so* going to fix this bug.  I think...


-- 

steven at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
         AssignedTo|unassigned at gcc dot gnu   |steven at gcc dot gnu dot
                   |dot org                     |org
             Status|NEW                         |ASSIGNED
   Last reconfirmed|2006-06-11 13:35:04         |2006-07-27 13:25:04
               date|                            |


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=26983

[Bug middle-end/26983] [4.0/4.1/4.2 Regression] Missing label with builtin_setjmp/longjmp

[atgraham at gmail dot com]

------- Comment #7 from atgraham at gmail dot com  2006-08-02 17:03 -------
Is it possible that #28493 is a symptom of the same problem?  Does anyone build
the darwin compiler with SjLj exceptions?


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=26983

[Bug middle-end/26983] [4.0/4.1/4.2 Regression] Missing label with builtin_setjmp/longjmp

[pinskia at gcc dot gnu dot org]

------- Comment #8 from pinskia at gcc dot gnu dot org  2006-08-02 17:24 -------
(In reply to comment #7)
> Is it possible that #28493 is a symptom of the same problem?  Does anyone build
> the darwin compiler with SjLj exceptions?

Why would they, dwarf-2 eh's overhead is much smaller if throws are not done
than sjlj exceptions.  Also I think this is a different problem and the problem
in the other PR is much older (dates back to 3.3/3.4 at least).


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=26983

[Bug middle-end/26983] [4.0/4.1/4.2 Regression] Missing label with builtin_setjmp/longjmp

[steven at gcc dot gnu dot org]

------- Comment #9 from steven at gcc dot gnu dot org  2006-09-10 10:59 -------
In GCC3, the label is not removed because it is in label_value_list.  In GCC4
we don't have that list anymore. That means we have to trust LABEL_NUSES, or we
have to force preservation of the label via LABEL_PRESERVE_P.  I'm inclined to
go with the former, but LABEL_NUSES is notoriously unreliable so I'm not
entirely comfortable with using it... :-/


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=26983

[Bug middle-end/26983] [4.0/4.1/4.2 Regression] Missing label with builtin_setjmp/longjmp

[steven at gcc dot gnu dot org]

------- Comment #10 from steven at gcc dot gnu dot org  2006-09-10 11:16 -------
I've decided to go with LABEL_PRESERVE_P after all...

Index: builtins.c
===================================================================
--- builtins.c  (revision 116785)
+++ builtins.c  (working copy)
@@ -760,6 +760,12 @@ expand_builtin_setjmp (tree arglist, rtx

   emit_label (next_lab);

+  /* Because setjmp and longjmp are not represented in the CFG, a cfgcleanup
+     may find that the basic block starting with NEXT_LAB is unreachable.
+     The whole block, along with NEXT_LAB, would be removed.  Make sure that
+     never happens.  */
+  LABEL_PRESERVE_P (next_lab) = 1;
+
   expand_builtin_setjmp_receiver (next_lab);

   /* Set TARGET to one.  */


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=26983

[Bug middle-end/26983] [4.0/4.1/4.2 Regression] Missing label with builtin_setjmp/longjmp

[patchapp at dberlin dot org]

------- Comment #11 from patchapp at dberlin dot org  2006-09-10 18:40 -------
Subject: Bug number PR26983

A patch for this bug has been added to the patch tracker.
The mailing list url for the patch is
http://gcc.gnu.org/ml/gcc-patches/2006-09/msg00370.html


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=26983

[Bug middle-end/26983] [4.0/4.1/4.2 Regression] Missing label with builtin_setjmp/longjmp

[steven at gcc dot gnu dot org]

------- Comment #12 from steven at gcc dot gnu dot org  2006-09-10 20:09 -------
Subject: Bug 26983

Author: steven
Date: Sun Sep 10 20:08:58 2006
New Revision: 116826

URL: http://gcc.gnu.org/viewcvs?root=gcc&view=rev&rev=116826
Log:
PR middle-end/26983

gcc/
        * builtins.c (expand_builtin_setjmp): Force next_lab to be
        preserved.

testsuite/
        * gcc.dg/pr26983.c: New test.

Added:
    trunk/gcc/testsuite/gcc.dg/pr26983.c
Modified:
    trunk/gcc/ChangeLog
    trunk/gcc/builtins.c
    trunk/gcc/testsuite/ChangeLog


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=26983

[Bug middle-end/26983] [4.0/4.1 Regression] Missing label with builtin_setjmp/longjmp

[steven at gcc dot gnu dot org]

------- Comment #13 from steven at gcc dot gnu dot org  2006-09-10 20:10 -------
Fixed on the trunk.


-- 

steven at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
         AssignedTo|steven at gcc dot gnu dot   |unassigned at gcc dot gnu
                   |org                         |dot org
             Status|ASSIGNED                    |NEW
            Summary|[4.0/4.1/4.2 Regression]    |[4.0/4.1 Regression] Missing
                   |Missing label with          |label with
                   |builtin_setjmp/longjmp      |builtin_setjmp/longjmp


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=26983

[Bug middle-end/26983] [4.0/4.1 Regression] Missing label with builtin_setjmp/longjmp

[sayle at gcc dot gnu dot org]

------- Comment #14 from sayle at gcc dot gnu dot org  2006-09-21 02:13 -------
Subject: Bug 26983

Author: sayle
Date: Thu Sep 21 02:13:48 2006
New Revision: 117106

URL: http://gcc.gnu.org/viewcvs?root=gcc&view=rev&rev=117106
Log:
2006-09-20  Steven Bosscher  <steven@gcc.gnu.org>

        PR middle-end/26983
        Backport from mainline
        * builtins.c (expand_builtin_setjmp): Force next_lab to be
        preserved.

        * gcc.dg/pr26983.c: New test.


Added:
    branches/gcc-4_1-branch/gcc/testsuite/gcc.dg/pr26983.c
Modified:
    branches/gcc-4_1-branch/gcc/ChangeLog
    branches/gcc-4_1-branch/gcc/builtins.c
    branches/gcc-4_1-branch/gcc/testsuite/ChangeLog


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=26983

[Bug middle-end/26983] [4.0 Regression] Missing label with builtin_setjmp/longjmp

[sayle at gcc dot gnu dot org]

------- Comment #15 from sayle at gcc dot gnu dot org  2006-09-21 23:38 -------
Subject: Bug 26983

Author: sayle
Date: Thu Sep 21 23:38:21 2006
New Revision: 117125

URL: http://gcc.gnu.org/viewcvs?root=gcc&view=rev&rev=117125
Log:
2006-09-21  Steven Bosscher  <steven@gcc.gnu.org>

        PR middle-end/26983
        Backport from mainline
        * builtins.c (expand_builtin_setjmp): Force next_lab to be
        preserved.

        * gcc.dg/pr26983.c: New test.


Added:
    branches/gcc-4_0-branch/gcc/testsuite/gcc.dg/pr26983.c
Modified:
    branches/gcc-4_0-branch/gcc/ChangeLog
    branches/gcc-4_0-branch/gcc/builtins.c
    branches/gcc-4_0-branch/gcc/testsuite/ChangeLog


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=26983

[Bug middle-end/26983] [4.0 Regression] Missing label with builtin_setjmp/longjmp

[roger at eyesopen dot com]

------- Comment #16 from roger at eyesopen dot com  2006-09-22 15:40 -------
Fixed everywhere.  Eric even has an improved patch/fix for mainline, but the
backports of this change are sufficient to resolve the current PR.  Thanks
to Steven for coming up with the solution.


-- 

roger at eyesopen dot com changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|NEW                         |RESOLVED
         Resolution|                            |FIXED


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=26983