[Bug debug/96471] New: ICE: fortran+gnat: build_abbrev_table, at dwarf2out.c: -g -fdebug-types-section

[Bug debug/96471] New: ICE: fortran+gnat: build_abbrev_table, at dwarf2out.c: -g -fdebug-types-section

[jan.kratochvil at redhat dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=96471

            Bug ID: 96471
           Summary: ICE: fortran+gnat: build_abbrev_table, at dwarf2out.c:
                    -g -fdebug-types-section
           Product: gcc
           Version: 11.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: debug
          Assignee: unassigned at gcc dot gnu.org
          Reporter: jan.kratochvil at redhat dot com
  Target Milestone: ---

2ac7fe2769890fe4c146da9cfa6d0eabb185d7db = 2020-08-03

gfortran -O2 -g -fdebug-types-section -fallow-argument-mismatch -fopenmp -c 1.F
-o 1.o
internal compiler error: in build_abbrev_table, at dwarf2out.c:9086
0x641d76 build_abbrev_table
        ../../gccgitclean/gcc/dwarf2out.c:9086
0xa63da7 build_abbrev_table
        ../../gccgitclean/gcc/dwarf2out.c:9143
0xa63da7 build_abbrev_table
        ../../gccgitclean/gcc/dwarf2out.c:9143
0xa64233 output_comdat_type_unit
        ../../gccgitclean/gcc/dwarf2out.c:11277
0xa8f19e dwarf2out_finish
        ../../gccgitclean/gcc/dwarf2out.c:31567

gcc -c -g -fdebug-types-section gnatcoll-storage_pools-alignment.adb 
+===========================GNAT BUG DETECTED==============================+
| 11.0.0 20200803 (experimental) (x86_64-pc-linux-gnu) GCC error:          |
| in build_abbrev_table, at dwarf2out.c:9086                               |
| Error detected around
/quad/home/jkratoch/redhat/gccgitclean-root/lib/gcc/x86_64-pc-linux-gnu/11.0.0/adainclude/s-stoele.adb:70:31|
...
raised TYPES.UNRECOVERABLE_ERROR : comperr.adb:407

Possibly a duplicate of:
lto1: internal compiler error: in build_abbrev_table, at dwarf2out.c:7478
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=58528
ICE: in build_abbrev_table, at dwarf2out.c:10477 with -g
-feliminate-dwarf2-dups
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=47361

[Bug debug/96471] ICE: fortran+gnat: build_abbrev_table, at dwarf2out.c: -g -fdebug-types-section

[jan.kratochvil at redhat dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=96471

Jan Kratochvil <jan.kratochvil at redhat dot com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |jan.kratochvil at redhat dot com

--- Comment #1 from Jan Kratochvil <jan.kratochvil at redhat dot com> ---
Created attachment 48996
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=48996&action=edit
.tar.xz reproducer for: fortran

[Bug debug/96471] ICE: fortran+gnat: build_abbrev_table, at dwarf2out.c: -g -fdebug-types-section

[jan.kratochvil at redhat dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=96471

--- Comment #2 from Jan Kratochvil <jan.kratochvil at redhat dot com> ---
Created attachment 48997
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=48997&action=edit
.tar.xz reproducer for: gnat

[Bug debug/96471] ICE: fortran+gnat: build_abbrev_table, at dwarf2out.c: -g -fdebug-types-section

[rguenth at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=96471

Richard Biener <rguenth at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |NEW
     Ever confirmed|0                           |1
           Keywords|                            |ice-on-valid-code
                 CC|                            |rguenth at gcc dot gnu.org
   Last reconfirmed|                            |2020-08-05

--- Comment #3 from Richard Biener <rguenth at gcc dot gnu.org> ---
Confirmed.

[Bug debug/96471] ICE: fortran+gnat: build_abbrev_table, at dwarf2out.c: -g -fdebug-types-section

[rguenth at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=96471

--- Comment #4 from Richard Biener <rguenth at gcc dot gnu.org> ---
Created attachment 49002
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=49002&action=edit
reduced fortran testcase

Manually reduced the fortran testcase down to a single file, now reproduces
with

> ./f951 -quiet 1.F -O -g -fopenmp -fdebug-types-section

[Bug debug/96471] ICE: fortran+gnat: build_abbrev_table, at dwarf2out.c: -g -fdebug-types-section

[rguenth at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=96471

--- Comment #5 from Richard Biener <rguenth at gcc dot gnu.org> ---
And auto reduce + some manual sanitizing:

      SUBROUTINE CMUMPS_SCATTER_DIST_RHS(
     &           POSINRHSCOMP_FWD, IFIRSTNOTTOUCHED,
     &           NBRECORDS)
      INTEGER, INTENT(IN)    :: POSINRHSCOMP_FWD(N)
        CALL CMUMPS_DR_ASSEMBLE_LOCAL()
      CONTAINS
        SUBROUTINE CMUMPS_DR_ASSEMBLE_LOCAL()
!$OMP PARALLEL DO PRIVATE(I, IRHSCOMP, Iglob)
          DO I = IFIRSTNOTTOUCHED, NBRECORDS
            IRHSCOMP = POSINRHSCOMP_FWD(I)
          ENDDO
        END SUBROUTINE CMUMPS_DR_ASSEMBLE_LOCAL
      END SUBROUTINE CMUMPS_SCATTER_DIST_RHS

[Bug debug/96471] ICE: fortran+gnat: build_abbrev_table, at dwarf2out.c: -g -fdebug-types-section

[rguenth at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=96471

--- Comment #6 from Richard Biener <rguenth at gcc dot gnu.org> ---
So the DIEs in question are

DIE    0: DW_TAG_subrange_type (0x7ffff69f3e10)
  abbrev id: 0 offset: 0 mark: 1
  DW_AT_type: die -> 0 (0x7ffff69f3eb0)
  DW_AT_upper_bound: die -> 0 (0x7ffff69f30f0)

refering to

DIE    0: DW_TAG_variable (0x7ffff69f30f0)
  abbrev id: 0 offset: 0 mark: 0
  DW_AT_type: die -> 0 (0x7ffff69d1d70)
  DW_AT_artificial: 1

where the subrange type is part of a type unit.

I think type units do not work this way and a type die like this should
disqualify the whole thing from becoming externalized into a type unit in the
first place?  There is should_move_die_to_comdat which already excludes
DIEs containing subprogram definitions, shouldn't all references to
non-type non-declaration DIEs also prevent a DIE from being externalized?

So for the specific case that's too early(?), after comdat breakout we still
see

    DIE    0: DW_TAG_array_type (0x7ffff69f8140)
      abbrev id: 0 offset: 0 mark: 0
      DW_AT_type: die -> 0 (0x7ffff69f8000)
        DIE    0: DW_TAG_subrange_type (0x7ffff69f8190)
          abbrev id: 0 offset: 0 mark: 0
          DW_AT_type: die -> 0 (0x7ffff69f8050)
          DW_AT_upper_bound: location descriptor:
            (0x7ffff69d1eb0) DW_OP_GNU_variable_value die -> 0
(0x7ffff69f30f0), 0

but then resolve_addr this into a direct DIE ref which eventually
copy_decls_walk would handle.  There's also note_variable_value
doing some location frobbing from decls to DIEs which is done after
comdat breakout and which would expose more such situations, so
re-ordering that would make sense.  Note I think
that even location lists are unwanted in type units.  Unfortunately
the DWARF standard doesn't list what is and what is not allowed in type
units.  Eventually one could strip the type unit off those unsupported
constructs and instead "complete" them in the main unit somehow.

Since resolve_addr runs only at dwarf2out_finish time we need to look
at the location case either disqualifying stuff or doing magic in
copy_decls_for_unworthy_types.

[Bug debug/96471] ICE: fortran+gnat: build_abbrev_table, at dwarf2out.c: -g -fdebug-types-section

[rguenth at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=96471

--- Comment #7 from Richard Biener <rguenth at gcc dot gnu.org> ---
Created attachment 49008
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=49008&action=edit
hackish patch

The following implements this (just the very special case of a single location
expression with a direct DIE ref).  It also re-orders note_variable_value
which might be an obvious part.

Now the question is whether such a type unit makes sense:

 <0><17>: Abbrev Number: 1 (DW_TAG_type_unit)
    <18>   DW_AT_language    : 14       (Fortran 95)
    <19>   DW_AT_stmt_list   : 0x0
 <1><1d>: Abbrev Number: 2 (DW_TAG_structure_type)
    <1e>   DW_AT_name        : (indirect string, offset: 0x1d0):
FRAME.cmumps_sc
atter_dist_rhs
    <22>   DW_AT_byte_size   : 32
    <23>   DW_AT_sibling     : <0x58>
 <2><27>: Abbrev Number: 3 (DW_TAG_member)
    <28>   DW_AT_name        : (indirect string, offset: 0x1b6):
posinrhscomp_fw
d
    <2c>   DW_AT_decl_file   : 1
    <2d>   DW_AT_decl_line   : 1
    <2e>   DW_AT_type        : <0x58>
    <32>   DW_AT_data_member_location: 0
...
 <1><58>: Abbrev Number: 4 (DW_TAG_restrict_type)
    <59>   DW_AT_type        : <0x64>
...
 <1><64>: Abbrev Number: 6 (DW_TAG_pointer_type)
    <65>   DW_AT_byte_size   : 8
    <66>   DW_AT_type        : <0x70>
...
 <1><70>: Abbrev Number: 8 (DW_TAG_array_type)
    <71>   DW_AT_type        : <0x83>
    <75>   DW_AT_sibling     : <0x83>
 <2><79>: Abbrev Number: 9 (DW_TAG_subrange_type)
    <7a>   DW_AT_type        : <0x8a>
    <7e>   DW_AT_upper_bound : <0x9a>
...
 <1><91>: Abbrev Number: 11 (DW_TAG_subprogram)
    <92>   DW_AT_external    : 1
    <92>   DW_AT_name        : (indirect string, offset: 0x1e):
cmumps_scatter_dist_rhs
    <96>   DW_AT_linkage_name: (indirect string, offset: 0x5c):
cmumps_scatter_dist_rhs_
    <9a>   DW_AT_declaration : 1
 <2><9a>: Abbrev Number: 12 (DW_TAG_variable)
    <9b>   DW_AT_type        : <0x8a>
    <9f>   DW_AT_artificial  : 1