[Bug varobj/25470] Assertion hit in maybe_negate_by_bytes

[Bug varobj/25470] Assertion hit in maybe_negate_by_bytes

[tromey at sourceware dot org]

https://sourceware.org/bugzilla/show_bug.cgi?id=25470

--- Comment #9 from Tom Tromey <tromey at sourceware dot org> ---
What is the DWARF emitted for one of these non-zero but non-byte-sized
types?
It ought to have a byte size (the storage size), a bit size, and optionally
a bit offset.

Removing the assert from maybe_negate_by_bytes and replacing it with

  /* 0-length integer types are possible in Zig, at least.  */
  if (len == 0)
    return false;


... at least makes symbol reading not crash.
I'd have to write a test case to see if it really works though.

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[Bug varobj/25470] Assertion hit in maybe_negate_by_bytes

[tromey at sourceware dot org]

https://sourceware.org/bugzilla/show_bug.cgi?id=25470

Tom Tromey <tromey at sourceware dot org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
   Last reconfirmed|                            |2020-08-14
           Assignee|unassigned at sourceware dot org   |tromey at sourceware dot org
             Status|UNCONFIRMED                 |NEW
     Ever confirmed|0                           |1

--- Comment #10 from Tom Tromey <tromey at sourceware dot org> ---
I have a patch for most of this.
I think assignment still doesn't work.
And, I am not sure it will work on big-endian machines as-is;
I never remember the rule for bit-numbering on big-endian.

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[Bug symtab/25470] Assertion hit in maybe_negate_by_bytes

[tromey at sourceware dot org]

https://sourceware.org/bugzilla/show_bug.cgi?id=25470

Tom Tromey <tromey at sourceware dot org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
          Component|varobj                      |symtab

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[Bug symtab/25470] Assertion hit in maybe_negate_by_bytes

[tromey at sourceware dot org]

https://sourceware.org/bugzilla/show_bug.cgi?id=25470

--- Comment #11 from Tom Tromey <tromey at sourceware dot org> ---
https://sourceware.org/pipermail/gdb-patches/2020-August/171309.html

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[Bug symtab/25470] Assertion hit in maybe_negate_by_bytes

[cvs-commit at gcc dot gnu.org]

https://sourceware.org/bugzilla/show_bug.cgi?id=25470

--- Comment #12 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=20a5fcbd5b28cca88511ac5a9ad5e54251e8fa6d

commit 20a5fcbd5b28cca88511ac5a9ad5e54251e8fa6d
Author: Tom Tromey <tom@tromey.com>
Date:   Wed Sep 23 09:39:24 2020 -0600

    Handle bit offset and bit size in base types

    PR symtab/25470 points out that the Zig programming language allows
    integers of various bit sizes (including zero), not just sizes that
    are a multiple of 8.

    This is supported in DWARF by applying both a byte size and a
    DW_AT_bit_size.

    This patch adds support for this feature to integer and boolean types.
    Other base types are not handled -- for floating-point types, this
    didn't seem to make sense, and for character types I didn't see much
    need.  (These can be added later if desired.)

    I've also added support for DW_AT_data_bit_offset at the same time.  I
    don't know whether the Zig compiler requires this, but it was
    described in the same section in the DWARF standard and was easy to
    add.

    A new test case is supplied, using the DWARF assembler.

    gdb/ChangeLog
    2020-09-23  Tom Tromey  <tom@tromey.com>

            PR symtab/25470:
            * value.c (unpack_long, pack_long, pack_unsigned_long): Handle bit
            offset and bit size.
            * printcmd.c (print_scalar_formatted): Handle zero-length
            integer.
            (print_scalar_formatted): Use bit_size_differs_p.
            * gdbtypes.h (enum type_specific_kind) <TYPE_SPECIFIC_INT>: New
            constant.
            (union type_specific): <int_stuff>: New member.
            (struct type) <bit_size_differs_p, bit_size, bit_offset>: New
            methods.
            * gdbtypes.c (init_integer_type, init_boolean_type): Initialize
            TYPE_SPECIFIC_FIELD.
            (recursive_dump_type, copy_type_recursive): Update.
            * dwarf2/read.c (read_base_type): Handle DW_AT_bit_size and
            DW_AT_data_bit_offset.

    gdb/testsuite/ChangeLog
    2020-09-23  Tom Tromey  <tom@tromey.com>

            * gdb.dwarf2/intbits.exp: New file.
            * gdb.dwarf2/intbits.c: New file.

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[Bug symtab/25470] Assertion hit in maybe_negate_by_bytes

[tromey at sourceware dot org]

https://sourceware.org/bugzilla/show_bug.cgi?id=25470

Tom Tromey <tromey at sourceware dot org> changed:

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

--- Comment #13 from Tom Tromey <tromey at sourceware dot org> ---
Fixed.
It'll be in gdb 11 but that isn't available as a target milestone
in bugzilla yet.

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[Bug symtab/25470] Assertion hit in maybe_negate_by_bytes

[tromey at sourceware dot org]

https://sourceware.org/bugzilla/show_bug.cgi?id=25470

Tom Tromey <tromey at sourceware dot org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
   Target Milestone|---                         |11.1

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