[Bug testsuite/30158] New: rustc testsuite fails with 13.1, apparently worked before with trunk 20230114 on i686-linux-gnu and powerpc64le-linux-gnu

[Bug testsuite/30158] New: rustc testsuite fails with 13.1, apparently worked before with trunk 20230114 on i686-linux-gnu and powerpc64le-linux-gnu

[doko at debian dot org]

https://sourceware.org/bugzilla/show_bug.cgi?id=30158

            Bug ID: 30158
           Summary: rustc testsuite fails with 13.1, apparently worked
                    before with trunk 20230114 on i686-linux-gnu and
                    powerpc64le-linux-gnu
           Product: gdb
           Version: 13.1
            Status: NEW
          Severity: normal
          Priority: P2
         Component: testsuite
          Assignee: unassigned at sourceware dot org
          Reporter: doko at debian dot org
  Target Milestone: ---

the rustc testsuite fails with 13.1 on i686-linux-gnu and
powerpc64le-linux-gnu, apparently worked before with trunk 20230114, both
reported on Debian and Ubuntu:

https://bugs.launchpad.net/ubuntu/+source/rustc/+bug/2007642/comments/10
claims:

/build/gdb-i4hVub/gdb-13.1/gdb/frame.c:2457: internal-error: inside_main_func:
Assertion `block != nullptr' failed.
A problem internal to GDB has been detected,
further debugging may prove unreliable.


https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=1031745

same internal error

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[Bug testsuite/30158] rustc testsuite fails with 13.1, apparently worked before with trunk 20230114 on i686-linux-gnu and powerpc64le-linux-gnu

[doko at debian dot org]

https://sourceware.org/bugzilla/show_bug.cgi?id=30158

Matthias Klose <doko at debian dot org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Target|                            |i686-linux-gnu
                   |                            |powerpc64le-linux-gnu

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[Bug testsuite/30158] rustc testsuite fails with 13.1, apparently worked before with trunk 20230114 on i686-linux-gnu and powerpc64le-linux-gnu

[hector.oron at gmail dot com]

https://sourceware.org/bugzilla/show_bug.cgi?id=30158

HectorOron <hector.oron at gmail dot com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |hector.oron at gmail dot com

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[Bug testsuite/30158] rustc testsuite fails with 13.1, apparently worked before with trunk 20230114 on i686-linux-gnu and powerpc64le-linux-gnu

[hector.oron at gmail dot com]

https://sourceware.org/bugzilla/show_bug.cgi?id=30158

HectorOron <hector.oron at gmail dot com> changed:

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

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[Bug testsuite/30158] rustc testsuite fails with 13.1, apparently worked before with trunk 20230114 on i686-linux-gnu and powerpc64le-linux-gnu

[hector.oron at gmail dot com]

https://sourceware.org/bugzilla/show_bug.cgi?id=30158

--- Comment #1 from HectorOron <hector.oron at gmail dot com> ---
Created attachment 14714
  --> https://sourceware.org/bugzilla/attachment.cgi?id=14714&action=edit
test case with readme

Attaching code that reproduces the issue. See README file.

Original source: https://salsa.debian.org/fg/rustc-gdb-1031745

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[Bug testsuite/30158] rustc testsuite fails with 13.1, apparently worked before with trunk 20230114 on i686-linux-gnu and powerpc64le-linux-gnu

[hector.oron at gmail dot com]

https://sourceware.org/bugzilla/show_bug.cgi?id=30158

--- Comment #2 from HectorOron <hector.oron at gmail dot com> ---
With attached testcase I am able to reproduce the issue using gdb 13.1, but it
works using 13.0.91.20230210.

It might be related to the patch that fixed PR/30116.

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[Bug testsuite/30158] rustc testsuite fails with 13.1, apparently worked before with trunk 20230114 on i686-linux-gnu and powerpc64le-linux-gnu

[tromey at sourceware dot org]

https://sourceware.org/bugzilla/show_bug.cgi?id=30158

Tom Tromey <tromey at sourceware dot org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
           Assignee|unassigned at sourceware dot org   |tromey at sourceware dot org

--- Comment #3 from Tom Tromey <tromey at sourceware dot org> ---
Ugh.  I'll investigate.

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[Bug testsuite/30158] rustc testsuite fails with 13.1, apparently worked before with trunk 20230114 on i686-linux-gnu and powerpc64le-linux-gnu

[hector.oron at gmail dot com]

https://sourceware.org/bugzilla/show_bug.cgi?id=30158

--- Comment #4 from HectorOron <hector.oron at gmail dot com> ---
I confirm that reverting patch for PR/30116 makes the rust testsuite work again
(for me).

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[Bug testsuite/30158] rustc testsuite fails with 13.1, apparently worked before with trunk 20230114 on i686-linux-gnu and powerpc64le-linux-gnu

[tromey at sourceware dot org]

https://sourceware.org/bugzilla/show_bug.cgi?id=30158

--- Comment #5 from Tom Tromey <tromey at sourceware dot org> ---
The crash is in inside_main_function, due to the modifications here:

    commit 9370fd51ebfca8a8acacaecb92c57ee54f4f8382
    gdb: detect main function even when there's no matching msymbol

First, gdb doesn't find the minsym, probably because the msyms
contain:

[99] t 0x90c0 _ZN17rustc_gdb_10317454main17h5b5be7fe16a97225E section .text 
rustc_gdb_1031745::main::h5b5be7fe16a97225  zko06yobckx336v

... but we're looking for:

(top-gdb) p name
$13 = 0x292e0c0 "rustc_gdb_1031745::main"

The _Z overloading strikes again.

Anyway somehow we find a full symbol for this, but it doesn't
have a block, so the assert fails.

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[Bug testsuite/30158] rustc testsuite fails with 13.1, apparently worked before with trunk 20230114 on i686-linux-gnu and powerpc64le-linux-gnu

[tromey at sourceware dot org]

https://sourceware.org/bugzilla/show_bug.cgi?id=30158

--- Comment #6 from Tom Tromey <tromey at sourceware dot org> ---
rustc decides to emit both:

 <2><2f5b>: Abbrev Number: 10 (DW_TAG_subprogram)
...
    <2f6e>   DW_AT_name        : (indirect string, offset: 0x23a): main

and

 <2><2f95>: Abbrev Number: 2 (DW_TAG_namespace)
    <2f96>   DW_AT_name        : (indirect string, offset: 0x23a): main

in the same scope.

Then the lookup finds the wrong one, because gdb's symbol tables
are bad and still follow C namespace rules.

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[Bug testsuite/30158] rustc testsuite fails with 13.1, apparently worked before with trunk 20230114 on i686-linux-gnu and powerpc64le-linux-gnu

[tromey at sourceware dot org]

https://sourceware.org/bugzilla/show_bug.cgi?id=30158

--- Comment #7 from Tom Tromey <tromey at sourceware dot org> ---
We can avoid the crash pretty easily but stopping the 'bt'
before _start is harder.

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[Bug testsuite/30158] rustc testsuite fails with 13.1, apparently worked before with trunk 20230114 on i686-linux-gnu and powerpc64le-linux-gnu

[tromey at sourceware dot org]

https://sourceware.org/bugzilla/show_bug.cgi?id=30158

--- Comment #8 from Tom Tromey <tromey at sourceware dot org> ---
Another thought here is it would probably be better on the whole
to use the main symbol's linkage name; but that too seems like
a larger change.

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[Bug testsuite/30158] rustc testsuite fails with 13.1, apparently worked before with trunk 20230114 on i686-linux-gnu and powerpc64le-linux-gnu

[tromey at sourceware dot org]

https://sourceware.org/bugzilla/show_bug.cgi?id=30158

--- Comment #9 from Tom Tromey <tromey at sourceware dot org> ---
https://sourceware.org/pipermail/gdb-patches/2023-February/197370.html

I'll apply to the gdb 13 branch as well when it goes in.

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[Bug testsuite/30158] rustc testsuite fails with 13.1, apparently worked before with trunk 20230114 on i686-linux-gnu and powerpc64le-linux-gnu

[hector.oron at gmail dot com]

https://sourceware.org/bugzilla/show_bug.cgi?id=30158

--- Comment #10 from HectorOron <hector.oron at gmail dot com> ---
(In reply to Tom Tromey from comment #9)
> https://sourceware.org/pipermail/gdb-patches/2023-February/197370.html

Thanks! That worked with the test case.

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[Bug testsuite/30158] rustc testsuite fails with 13.1, apparently worked before with trunk 20230114 on i686-linux-gnu and powerpc64le-linux-gnu

[hector.oron at gmail dot com]

https://sourceware.org/bugzilla/show_bug.cgi?id=30158

--- Comment #11 from HectorOron <hector.oron at gmail dot com> ---
Hello Tom,

  The testcase at https://salsa.debian.org/fg/rustc-gdb-1031745 has been update
to add one more failing test case scenario described at
https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=1031946

Fabian reports:
I updated the reproducer repo[0], broken and good output look like this:

----8<---- broken
Breakpoint 1 at 0x81dd: file src/main.rs, line 88.
[Thread debugging using libthread_db enabled]
Using host libthread_db library "/lib/x86_64-linux-gnu/libthread_db.so.1".

Breakpoint 1, rustc_gdb_1031745::main () at src/main.rs:88
88          zzz(); // #break
$1 = &rustc_gdb_1031745::Foo<[u8]> 0x7fffffffdd88
$2 = &rustc_gdb_1031745::Foo<rustc_gdb_1031745::Foo<[u8]>> 0x7fffffffdd88
$3 = &rustc_gdb_1031745::Foo<dyn core::fmt::Debug> {pointer: 0x555555593034,
vtable: 0x5555555a3000warning: (Internal error: pc 0x5555555a3000 in read in
CU, but not in symtab.)
warning: (Error: pc 0x5555555a3000 in address map, but not in symtab.)
}
$4 = alloc::boxed::Box<rustc_gdb_1031745::Foo<dyn core::fmt::Debug>,
alloc::alloc::Global> {pointer: 0x5555555a7ba0, vtable: 0x5555555a3000warning:
(Internal error: pc 0x5555555a3000 in read in CU, but not in symtab.)
warning: (Error: pc 0x5555555a3000 in address map, but not in symtab.)
}
$5 = &(i32, i32, [i32]) [(0, 1, 0), (2, 3, 0)]
$6 = &(i32, i32, dyn core::fmt::Debug) {pointer: 0x5555555a3020, vtable:
0x5555555a3030warning: (Internal error: pc 0x5555555a3030 in read in CU, but
not in symtab.)
warning: (Error: pc 0x5555555a3030 in address map, but not in symtab.)
}
---->8----

----8<---- good (gdb 12.1-4 from bookworm)
Breakpoint 1 at 0x81dd: file src/main.rs, line 88.
[Thread debugging using libthread_db enabled]
Using host libthread_db library "/lib/x86_64-linux-gnu/libthread_db.so.1".

Breakpoint 1, rustc_gdb_1031745::main () at src/main.rs:88
88          zzz(); // #break
$1 = &rustc_gdb_1031745::Foo<[u8]> {data_ptr: 0x7fffffffdd88, length: 4}
$2 = &rustc_gdb_1031745::Foo<rustc_gdb_1031745::Foo<[u8]>> {data_ptr:
0x7fffffffdd88, length: 4}
$3 = &rustc_gdb_1031745::Foo<dyn core::fmt::Debug> {pointer: 0x555555593034,
vtable: 0x5555555a3000}
$4 = alloc::boxed::Box<rustc_gdb_1031745::Foo<dyn core::fmt::Debug>,
alloc::alloc::Global> {pointer: 0x5555555a7ba0, vtable: 0x5555555a3000}
$5 = &(i32, i32, [i32]) {data_ptr: 0x555555593038, length: 2}
$6 = &(i32, i32, dyn core::fmt::Debug) {pointer: 0x5555555a3020, vtable:
0x5555555a3030}
---->8----

Since this no longer (fatally) affects the build of rustc, I opted for a
lower severity this time around. It looks like an issue with symbol
mapping/lookup again. Feel free to adjust if you consider this blocking.

0: https://salsa.debian.org/fg/rustc-gdb-1031745


I am attaching last git reproducer to the bug

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[Bug testsuite/30158] rustc testsuite fails with 13.1, apparently worked before with trunk 20230114 on i686-linux-gnu and powerpc64le-linux-gnu

[hector.oron at gmail dot com]

https://sourceware.org/bugzilla/show_bug.cgi?id=30158

--- Comment #12 from HectorOron <hector.oron at gmail dot com> ---
Created attachment 14721
  --> https://sourceware.org/bugzilla/attachment.cgi?id=14721&action=edit
test case with readme (v2) - one last issue after proposed patch

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[Bug testsuite/30158] rustc testsuite fails with 13.1, apparently worked before with trunk 20230114 on i686-linux-gnu and powerpc64le-linux-gnu

[tromey at sourceware dot org]

https://sourceware.org/bugzilla/show_bug.cgi?id=30158

--- Comment #13 from Tom Tromey <tromey at sourceware dot org> ---
(In reply to HectorOron from comment #11)

> Since this no longer (fatally) affects the build of rustc, I opted for a
> lower severity this time around. It looks like an issue with symbol
> mapping/lookup again. Feel free to adjust if you consider this blocking.

Would you mind submitting a separate bug for this?

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[Bug testsuite/30158] rustc testsuite fails with 13.1, apparently worked before with trunk 20230114 on i686-linux-gnu and powerpc64le-linux-gnu

[tromey at sourceware dot org]

https://sourceware.org/bugzilla/show_bug.cgi?id=30158

Tom Tromey <tromey at sourceware dot org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
   Target Milestone|---                         |13.2

--- Comment #14 from Tom Tromey <tromey at sourceware dot org> ---
Marking for 13.2

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[Bug testsuite/30158] rustc testsuite fails with 13.1, apparently worked before with trunk 20230114 on i686-linux-gnu and powerpc64le-linux-gnu

[tromey at sourceware dot org]

https://sourceware.org/bugzilla/show_bug.cgi?id=30158

Tom Tromey <tromey at sourceware dot org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |roidinev at gmail dot com

--- Comment #15 from Tom Tromey <tromey at sourceware dot org> ---
*** Bug 30224 has been marked as a duplicate of this bug. ***

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[Bug testsuite/30158] rustc testsuite fails with 13.1, apparently worked before with trunk 20230114 on i686-linux-gnu and powerpc64le-linux-gnu

[cvs-commit at gcc dot gnu.org]

https://sourceware.org/bugzilla/show_bug.cgi?id=30158

--- Comment #16 from cvs-commit at gcc dot gnu.org <cvs-commit at gcc dot gnu.org> ---
The master branch has been updated by Tom Tromey <tromey@sourceware.org>:

https://sourceware.org/git/gitweb.cgi?p=binutils-gdb.git;h=5f056fcb3dce947447063f5ab225042177a59722

commit 5f056fcb3dce947447063f5ab225042177a59722
Author: Tom Tromey <tromey@adacore.com>
Date:   Fri Feb 24 10:40:16 2023 -0700

    Fix crash in inside_main_func

    gdb 13.1 crashes while running the rust compiler's debugger tests.
    The crash has a number of causes.

    First, the rust compiler still uses the C++-like _Z mangling, but with
    its own twist -- some hex digits added to the end of a symbol.  So,
    while gdb finds the correct name of "main":

    (top-gdb) p name
    $13 = 0x292e0c0 "rustc_gdb_1031745::main"

    It isn't found in the minsyms, because C++ demangling yields:

    [99] t 0x90c0 _ZN17rustc_gdb_10317454main17h5b5be7fe16a97225E section .text
 rustc_gdb_1031745::main::h5b5be7fe16a97225  zko06yobckx336v

    This could perhaps be fixed.  I also filed a new PR to suggest
    preferring the linkage name of the main program.

    Next, the rust compiler emits both a DW_TAG_subprogram and a
    DW_TAG_namespace for "main".  This happens because the file is named
    "main.rs" -- i.e., the bug is specific to the source file name.  The
    crash also seems to require the nested function inside of 'main', at
    least for me.  The namespace always is generated, but perhaps this
    changes the ordering in the DWARF.

    When inside_main_func looks up the main symbol, it finds the namespace
    symbol rather than the function.  (I filed a bug about fixing gdb's
    symbol tables -- long overdue.)

    Meanwhile, as I think it's important to fix this crash sooner rather
    than later, this patch changes inside_main_func to check that the
    symbol that is found is LOC_BLOCK.  This perhaps should have been done
    in the first place, anyway.

    Bug: https://sourceware.org/bugzilla/show_bug.cgi?id=30158

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[Bug testsuite/30158] rustc testsuite fails with 13.1, apparently worked before with trunk 20230114 on i686-linux-gnu and powerpc64le-linux-gnu

[cvs-commit at gcc dot gnu.org]

https://sourceware.org/bugzilla/show_bug.cgi?id=30158

--- Comment #17 from cvs-commit at gcc dot gnu.org <cvs-commit at gcc dot gnu.org> ---
The gdb-13-branch branch has been updated by Tom Tromey
<tromey@sourceware.org>:

https://sourceware.org/git/gitweb.cgi?p=binutils-gdb.git;h=562403d4f5483e0787219fdb88da72c707c8d7f6

commit 562403d4f5483e0787219fdb88da72c707c8d7f6
Author: Tom Tromey <tromey@adacore.com>
Date:   Fri Feb 24 10:40:16 2023 -0700

    Fix crash in inside_main_func

    gdb 13.1 crashes while running the rust compiler's debugger tests.
    The crash has a number of causes.

    First, the rust compiler still uses the C++-like _Z mangling, but with
    its own twist -- some hex digits added to the end of a symbol.  So,
    while gdb finds the correct name of "main":

    (top-gdb) p name
    $13 = 0x292e0c0 "rustc_gdb_1031745::main"

    It isn't found in the minsyms, because C++ demangling yields:

    [99] t 0x90c0 _ZN17rustc_gdb_10317454main17h5b5be7fe16a97225E section .text
 rustc_gdb_1031745::main::h5b5be7fe16a97225  zko06yobckx336v

    This could perhaps be fixed.  I also filed a new PR to suggest
    preferring the linkage name of the main program.

    Next, the rust compiler emits both a DW_TAG_subprogram and a
    DW_TAG_namespace for "main".  This happens because the file is named
    "main.rs" -- i.e., the bug is specific to the source file name.  The
    crash also seems to require the nested function inside of 'main', at
    least for me.  The namespace always is generated, but perhaps this
    changes the ordering in the DWARF.

    When inside_main_func looks up the main symbol, it finds the namespace
    symbol rather than the function.  (I filed a bug about fixing gdb's
    symbol tables -- long overdue.)

    Meanwhile, as I think it's important to fix this crash sooner rather
    than later, this patch changes inside_main_func to check that the
    symbol that is found is LOC_BLOCK.  This perhaps should have been done
    in the first place, anyway.

    Bug: https://sourceware.org/bugzilla/show_bug.cgi?id=30158

    (cherry picked from commit 5f056fcb3dce947447063f5ab225042177a59722)

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[Bug testsuite/30158] rustc testsuite fails with 13.1, apparently worked before with trunk 20230114 on i686-linux-gnu and powerpc64le-linux-gnu

[tromey at sourceware dot org]

https://sourceware.org/bugzilla/show_bug.cgi?id=30158

Tom Tromey <tromey at sourceware dot org> changed:

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

--- Comment #18 from Tom Tromey <tromey at sourceware dot org> ---
Fixed.

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[Bug testsuite/30158] rustc testsuite fails with 13.1, apparently worked before with trunk 20230114 on i686-linux-gnu and powerpc64le-linux-gnu

[tromey at sourceware dot org]

https://sourceware.org/bugzilla/show_bug.cgi?id=30158

Tom Tromey <tromey at sourceware dot org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |nils at os dot inf.tu-dresden.de

--- Comment #19 from Tom Tromey <tromey at sourceware dot org> ---
*** Bug 29298 has been marked as a duplicate of this bug. ***

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