[Bug c++/115031] New: g++.dg/modules/pr99023_b.X FAILs

[Bug c++/115031] New: g++.dg/modules/pr99023_b.X FAILs

[ro at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=115031

            Bug ID: 115031
           Summary: g++.dg/modules/pr99023_b.X FAILs
           Product: gcc
           Version: 15.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c++
          Assignee: unassigned at gcc dot gnu.org
          Reporter: ro at gcc dot gnu.org
  Target Milestone: ---
              Host: sparc-sun-solaris2.11
            Target: sparc-sun-solaris2.11
             Build: sparc-sun-solaris2.11

The g++.dg/modules/pr99023_b.X test FAILs on Solaris/SPARC when using a
32-bit-default
compiler:

FAIL: g++.dg/modules/pr99023_b.X -std=c++2a  1 blank line(s) in output
FAIL: g++.dg/modules/pr99023_b.X -std=c++2a (test for excess errors)

Excess errors:
cc1plus: out of memory allocating 1048344 bytes after a total of 7913472 bytes

Strangely, this doesn't happen with a 32-bit-default Solaris/x86 compiler.

The failure (I haven't checked the specifics) goes back as far as 20210219.

[Bug c++/115031] g++.dg/modules/pr99023_b.X FAILs

[ro at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=115031

Rainer Orth <ro at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |nathan at gcc dot gnu.org

--- Comment #1 from Rainer Orth <ro at gcc dot gnu.org> ---
Nathan, any suggestion where to start looking here?

[Bug c++/115031] g++.dg/modules/pr99023_b.X FAILs

[ro at CeBiTec dot Uni-Bielefeld.DE]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=115031

--- Comment #2 from ro at CeBiTec dot Uni-Bielefeld.DE <ro at CeBiTec dot Uni-Bielefeld.DE> ---
I've done some digging now, comparing mmap calls on Solaris/i386 and
Solaris/SPARC (counts and sizes each):

i386:

      2 4096
      7 8192
      5 16384
      7 32768
      4 65536
      3 131072
      2 262144
      3 524288
      2 1048576
      1 1662976
    892 2097152
      2 3313664
      1 4194304

  total ca. 1784 MB
  getconf PAGE_SIZE -> 4096

sparc:

    491 8192
      6 16384
      4 32768
      3 65536
      2 131072
      1 262144
      2 524288
      1 1048576
      1 2097152
    986 4194304

  total ca. 3947 MB
  getconf PAGE_SIZE -> 8192

In a next step, I disabled MAPPED_{READING, WRITING} in
gcc/cp/module.cc, but that made almost no different on i386 and didn't
cure the allocation failure on sparc.

Looking closer at the mmap64 call chains, they are primarily from
ggc_internal_alloc.  So I undef'ed USING_MMAP there, with astonishing
results for runtimes:

* i386 with mmap in module.cc and ggc-page.cc:

real          30.12
user          29.62
sys            0.14

* i386 with fileio in module.cc and mmap in ggc-page:

real          29.93
user          29.50
sys            0.21

* i386 with fileio in module.cc and USING_MMAP undef'ed in ggc-page.cc:

real          28.53
user          28.19
sys            0.16

* sparc with the same combination allows the test to run to complition
  for the first time:

real          37.81
user          37.46
sys            0.14

I wonder what to make of that beyond the failing sparc testcase.

[Bug c++/115031] g++.dg/modules/pr99023_b.X FAILs

[cvs-commit at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=115031

--- Comment #3 from GCC Commits <cvs-commit at gcc dot gnu.org> ---
The master branch has been updated by Rainer Orth <ro@gcc.gnu.org>:

https://gcc.gnu.org/g:32f99225bcaae9b792aec143239d17f2b7e2c54b

commit r15-927-g32f99225bcaae9b792aec143239d17f2b7e2c54b
Author: Rainer Orth <ro@CeBiTec.Uni-Bielefeld.DE>
Date:   Thu May 30 15:00:59 2024 +0200

    ggc: Reduce GGC_QUIRE_SIZE on Solaris/SPARC [PR115031]

    g++.dg/modules/pr99023_b.X currently FAILs on 32-bit Solaris/SPARC:

    FAIL: g++.dg/modules/pr99023_b.X -std=c++2a  1 blank line(s) in output
    FAIL: g++.dg/modules/pr99023_b.X -std=c++2a (test for excess errors)

    Excess errors:
    cc1plus: out of memory allocating 1048344 bytes after a total of 7913472
bytes

    It turns out that this exhaustion of the 32-bit address space happens
    due to a combination of three issues:

    * the SPARC pagesize of 8 kB,

    * ggc-page.cc's chunk size of 512 * pagesize, i.e. 4 MB, and

    * mmap adding two 8 kB unmapped red-zone pages to each mapping

    which result in the 4 MB mappings to actually consume 4.5 MB of address
    space.

    To avoid this, this patch reduces the chunk size so it remains at 4 MB
    even when combined with the red-zone pages, as recommended by mmap(2).

    Tested on sparc-sun-solaris2.11 and sparcv9-sun-solaris2.11.

    2024-05-29  Rainer Orth  <ro@CeBiTec.Uni-Bielefeld.DE>

            gcc:
            PR c++/115031
            * config/sparc/sol2.h (GGC_QUIRE_SIZE): Define as 510.

[Bug c++/115031] g++.dg/modules/pr99023_b.X FAILs

[ro at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=115031

Rainer Orth <ro at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
           Assignee|unassigned at gcc dot gnu.org      |ro at gcc dot gnu.org
                URL|                            |https://gcc.gnu.org/piperma
                   |                            |il/gcc-patches/2024-May/653
                   |                            |136.html
   Target Milestone|---                         |15.0
             Status|UNCONFIRMED                 |RESOLVED
         Resolution|---                         |FIXED

--- Comment #4 from Rainer Orth <ro at gcc dot gnu.org> ---
Fixed for GCC 15.0.