[Bug symtab/29561] New: [gdb/symtab] During symbol reading: file index out of range

[Bug symtab/29561] New: [gdb/symtab] During symbol reading: file index out of range

[vries at gcc dot gnu.org]

https://sourceware.org/bugzilla/show_bug.cgi?id=29561

            Bug ID: 29561
           Summary: [gdb/symtab] During symbol reading: file index out of
                    range
           Product: gdb
           Version: HEAD
            Status: NEW
          Severity: normal
          Priority: P2
         Component: symtab
          Assignee: unassigned at sourceware dot org
          Reporter: vries at gcc dot gnu.org
  Target Milestone: ---

Fairly simple test-case:
...
$ gcc -g ~/hello.c
...

With gdb build from trunk:
...
$ gdb -q -batch -iex "set complaints 100" ./a.out  -ex "maint expand-symtabs"
During symbol reading: file index out of range
$
...

With system gdb (11.1):
...
$ gdb -q -batch -iex "set complaints 100" ./a.out  -ex "maint expand-symtabs" 
$
...

DIE that is complained about is:
...
 <1><4b>: Abbrev Number: 2 (DW_TAG_variable)
    <4c>   DW_AT_name        : _IO_stdin_used
    <50>   DW_AT_decl_file   : 1
    <51>   DW_AT_decl_line   : 23
    <52>   DW_AT_type        : <0x67>
    <56>   DW_AT_external    : 1
    <56>   DW_AT_location    : 9 byte block: 3 70 5 40 0 0 0 0 0       
(DW_OP_addr: 400570)
...

Referring to file/dir info:
...
 The Directory Table is empty.

 The File Name Table (offset 0x78):
  Entry Dir     Time    Size    Name
  1     0       0       0       init.c
...

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[Bug symtab/29561] [gdb/symtab] During symbol reading: file index out of range

[vries at gcc dot gnu.org]

https://sourceware.org/bugzilla/show_bug.cgi?id=29561

Tom de Vries <vries at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |tromey at sourceware dot org

--- Comment #1 from Tom de Vries <vries at gcc dot gnu.org> ---
Taking the maintenance command out of the equation, we still manage to trigger
the same problem:
...
$ gdb -q -batch -iex "set complaints 100" ./a.out -ex "info var _IO_stdin_used" 
During symbol reading: file index out of range
All variables matching regular expression "_IO_stdin_used":

File init.c:
23:     const int _IO_stdin_used;
...
Note how in the end we do manage to find the correct file for the variable.

Also, same problems occurs with -readnow, so this doesn't seem related to the
new index cooker.

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[Bug symtab/29561] [gdb/symtab] During symbol reading: file index out of range

[vries at gcc dot gnu.org]

https://sourceware.org/bugzilla/show_bug.cgi?id=29561

--- Comment #2 from Tom de Vries <vries at gcc dot gnu.org> ---
With bisect narrowing in on a window of 17 commits, my bet is on:
...
commit 6d263fe46e00afd8af3d609c1afd71d05eaf745e
Author: Tom Tromey <tromey@adacore.com>
Date:   Thu Jan 13 09:48:18 2022 -0700

    Avoid bad breakpoints with --gc-sections

    We found a case where --gc-sections can cause gdb to set an invalid
    breakpoint.  In the included test case, gdb will set a breakpoint with
    two locations, one of which is 0x0.

    The code in lnp_state_machine::check_line_address is intended to
    filter out this sort of problem, but in this case, the entire CU is
    empty, causing unrelocated_lowpc==0x0 -- which circumvents the check.

    It seems to me that if a CU is empty like this, then it is ok to
    simply ignore the line table, as there won't be any locations anyway.
...

Indeed the line table is empty for the CU, but the file table is not.

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[Bug symtab/29561] [gdb/symtab] During symbol reading: file index out of range

[vries at gcc dot gnu.org]

https://sourceware.org/bugzilla/show_bug.cgi?id=29561

Tom de Vries <vries at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |simark at simark dot ca

--- Comment #3 from Tom de Vries <vries at gcc dot gnu.org> ---
(In reply to Tom de Vries from comment #2)
> With bisect narrowing in on a window of 17 commits, my bet is on:
>     Avoid bad breakpoints with --gc-sections

Confirmed.

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[Bug symtab/29561] [gdb/symtab] During symbol reading: file index out of range

[vries at gcc dot gnu.org]

https://sourceware.org/bugzilla/show_bug.cgi?id=29561

--- Comment #4 from Tom de Vries <vries at gcc dot gnu.org> ---
Created attachment 14328
  --> https://sourceware.org/bugzilla/attachment.cgi?id=14328&action=edit
Tentative patch

Fixes the complaint, and doesn't regress gdb.ada/inline-section-gc.exp.

I'll put this through a full test run.

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[Bug symtab/29561] [gdb/symtab] During symbol reading: file index out of range

[vries at gcc dot gnu.org]

https://sourceware.org/bugzilla/show_bug.cgi?id=29561

--- Comment #5 from Tom de Vries <vries at gcc dot gnu.org> ---
(In reply to Tom de Vries from comment #4)
> Created attachment 14328 [details]
> Tentative patch
> 
> Fixes the complaint, and doesn't regress gdb.ada/inline-section-gc.exp.
> 
> I'll put this through a full test run.

That looks good, I'll add a test-case and submit.

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[Bug symtab/29561] [gdb/symtab] During symbol reading: file index out of range

[vries at gcc dot gnu.org]

https://sourceware.org/bugzilla/show_bug.cgi?id=29561

--- Comment #6 from Tom de Vries <vries at gcc dot gnu.org> ---
(In reply to Tom de Vries from comment #5)
> That looks good, I'll add a test-case and submit.

https://sourceware.org/pipermail/gdb-patches/2022-September/191758.html

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[Bug symtab/29561] [gdb/symtab] During symbol reading: file index out of range

[vries at gcc dot gnu.org]

https://sourceware.org/bugzilla/show_bug.cgi?id=29561

Tom de Vries <vries at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|NEW                         |RESOLVED
         Resolution|---                         |FIXED
   Target Milestone|---                         |13.1

--- Comment #7 from Tom de Vries <vries at gcc dot gnu.org> ---
https://sourceware.org/git/?p=binutils-gdb.git;a=commit;h=99d679e7b30ea9a0b6ffcd64e9ba35e43166151b

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