[Bug exp/20991] __int128 type support

[Bug exp/20991] __int128 type support

[ssbssa at sourceware dot org]

https://sourceware.org/bugzilla/show_bug.cgi?id=20991

Hannes Domani <ssbssa at sourceware dot org> changed:

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

--- Comment #4 from Hannes Domani <ssbssa at sourceware dot org> ---
(In reply to Tom Tromey from comment #0)
> I tried a couple experiments with __int128 and found some gdb issues.
> 
> My test code:
> 
> __int128 x = 72;
> 
> I compiled with -g -c then ran gdb on the .o.
> 
> Printing kind of works, but chooses hex by default and zero-pads:
> 
> (gdb) p x
> $1 = 0x00000000000000000000000000000048
> 
> Specifying decimal still zero-pads, which looks very weird:
> 
> (gdb) p/d x
> $2 = 00000000000000000000000000000072
> 
> Addition doesn't work:
> 
> (gdb) p x + 5
> That operation is not available on integers of more than 8 bytes.

There is no longer zero-padding since 8.1, but addition still doesn't work.

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[Bug exp/20991] __int128 type support

[cvs-commit at gcc dot gnu.org]

https://sourceware.org/bugzilla/show_bug.cgi?id=20991

--- Comment #5 from cvs-commit at gcc dot gnu.org <cvs-commit at gcc dot gnu.org> ---
The master branch has been updated by Tom de Vries <vries@sourceware.org>:

https://sourceware.org/git/gitweb.cgi?p=binutils-gdb.git;h=0057a7ee0d963eb9aee5cdfb9d6da5279bc8caf9

commit 0057a7ee0d963eb9aee5cdfb9d6da5279bc8caf9
Author: Tom de Vries <tdevries@suse.de>
Date:   Wed Jul 21 14:19:51 2021 +0200

    [gdb/testsuite] Add KFAILs for gdb.ada FAILs with gcc-11

    With gcc-11 we run into:
    ...
    (gdb) print pa_ptr.all^M
    That operation is not available on integers of more than 8 bytes.^M
    (gdb) KFAIL: gdb.ada/arrayptr.exp: scenario=all: print pa_ptr.all (PRMS:
gdb/20991)
    ...

    This is due to PR exp/20991 - "__int128 type support".  Mark this and
similar
    FAILs as KFAIL.

    Also mark this FAIL:
    ....
    (gdb) print pa_ptr(3)^M
    cannot subscript or call something of type `foo__packed_array_ptr'^M
    (gdb) FAIL: gdb.ada/arrayptr.exp: scenario=minimal: print pa_ptr(3)
    ...
    as a KFAIL for PR ada/28115 - "Support packed array encoded as
    DW_TAG_subrange_type".

    Tested on x86_64-linux, with gcc-10 and gcc-11.

    gdb/testsuite/ChangeLog:

    2021-07-21  Tom de Vries  <tdevries@suse.de>

            * gdb.ada/arrayptr.exp: Add KFAILs for PR20991 and PR28115.
            * gdb.ada/exprs.exp: Add KFAILs for PR20991.
            * gdb.ada/packed_array_assign.exp: Same.

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[Bug exp/20991] __int128 type support

[cvs-commit at gcc dot gnu.org]

https://sourceware.org/bugzilla/show_bug.cgi?id=20991

--- Comment #6 from cvs-commit at gcc dot gnu.org <cvs-commit at gcc dot gnu.org> ---
The gdb-11-branch branch has been updated by Tom de Vries
<vries@sourceware.org>:

https://sourceware.org/git/gitweb.cgi?p=binutils-gdb.git;h=f26101b199482bd13b5f9c45fb4f43a4eb8b16e6

commit f26101b199482bd13b5f9c45fb4f43a4eb8b16e6
Author: Tom de Vries <tdevries@suse.de>
Date:   Wed Jul 21 14:22:16 2021 +0200

    [gdb/testsuite] Add KFAILs for gdb.ada FAILs with gcc-11

    With gcc-11 we run into:
    ...
    (gdb) print pa_ptr.all^M
    That operation is not available on integers of more than 8 bytes.^M
    (gdb) KFAIL: gdb.ada/arrayptr.exp: scenario=all: print pa_ptr.all (PRMS:
gdb/20991)
    ...

    This is due to PR exp/20991 - "__int128 type support".  Mark this and
similar
    FAILs as KFAIL.

    Also mark this FAIL:
    ....
    (gdb) print pa_ptr(3)^M
    cannot subscript or call something of type `foo__packed_array_ptr'^M
    (gdb) FAIL: gdb.ada/arrayptr.exp: scenario=minimal: print pa_ptr(3)
    ...
    as a KFAIL for PR ada/28115 - "Support packed array encoded as
    DW_TAG_subrange_type".

    Tested on x86_64-linux, with gcc-10 and gcc-11.

    gdb/testsuite/ChangeLog:

    2021-07-21  Tom de Vries  <tdevries@suse.de>

            * gdb.ada/arrayptr.exp: Add KFAILs for PR20991 and PR28115.
            * gdb.ada/exprs.exp: Add KFAILs for PR20991.
            * gdb.ada/packed_array_assign.exp: Same.

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[Bug exp/20991] __int128 type support

[tromey at sourceware dot org]

https://sourceware.org/bugzilla/show_bug.cgi?id=20991

--- Comment #7 from Tom Tromey <tromey at sourceware dot org> ---
*** Bug 21185 has been marked as a duplicate of this bug. ***

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[Bug exp/20991] __int128 type support

[tromey at sourceware dot org]

https://sourceware.org/bugzilla/show_bug.cgi?id=20991

--- Comment #8 from Tom Tromey <tromey at sourceware dot org> ---
In bug #21185, using gcc's wide-int was suggested as one option.
I looked into this, and I can make wide-int compile in gdb
with some hacks.  However, since gdb already requires GMP,
I think it's probably better to just use that.

Also it seems like there are multiple parts to this bug.
Perhaps we should treat them individually...

* Parsers should recognize 128-bit types and lexers should make
  128-bit quantities.

* valops should extract a GMP from a struct value and work on that
  representation.

* Type ranges / dynamic props should be converted to 128-bit
  quantities where needed.  (My thinking here is that the
  data would be stored in some convenient & compact format,
  but convert to GMP when working with the values.)

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[Bug exp/20991] __int128 type support

[pedro at palves dot net]

https://sourceware.org/bugzilla/show_bug.cgi?id=20991

Pedro Alves <pedro at palves dot net> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |pedro at palves dot net

--- Comment #9 from Pedro Alves <pedro at palves dot net> ---
GMP has a surprising and unfortunate design choice that IMHO may make it
undesirable for a fixed-width type -- it uses the heap for _every_ integer.

This is last discussed in this thread:

 https://sourceware.org/pipermail/gdb/2022-October/050375.html

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[Bug exp/20991] __int128 type support

[tromey at sourceware dot org]

https://sourceware.org/bugzilla/show_bug.cgi?id=20991

--- Comment #10 from Tom Tromey <tromey at sourceware dot org> ---
(In reply to Pedro Alves from comment #9)
> GMP has a surprising and unfortunate design choice that IMHO may make it
> undesirable for a fixed-width type -- it uses the heap for _every_ integer.

I suspect it won't matter much, but if it does, we can always
adopt wide-int.

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[Bug exp/20991] __int128 type support

[pedro at palves dot net]

https://sourceware.org/bugzilla/show_bug.cgi?id=20991

--- Comment #11 from Pedro Alves <pedro at palves dot net> ---
Yeah, or something else.  As long as the type we use looks like an integer
(implements arithmetic operators, etc.), then swapping one implementation for
another is not a big deal.

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[Bug exp/20991] __int128 type support

[pedro at palves dot net]

https://sourceware.org/bugzilla/show_bug.cgi?id=20991

--- Comment #12 from Pedro Alves <pedro at palves dot net> ---
I was looking at whether GMP already has built-in support for _finite_
precision, for example so that we handle wraparound of "unsigned __int128"
values propertly, left shifting, etc.  I couldn't find anything for that, so I
guess we'd have to implement wraparound, etc. ourselves?

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[Bug exp/20991] __int128 type support

[tromey at sourceware dot org]

https://sourceware.org/bugzilla/show_bug.cgi?id=20991

--- Comment #13 from Tom Tromey <tromey at sourceware dot org> ---
(In reply to Pedro Alves from comment #12)
> I was looking at whether GMP already has built-in support for _finite_
> precision, for example so that we handle wraparound of "unsigned __int128"
> values propertly, left shifting, etc.  I couldn't find anything for that, so
> I guess we'd have to implement wraparound, etc. ourselves?

Yeah.  I suppose gcc's is nicer this way, you can specify the
precision.

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[Bug exp/20991] __int128 type support

[tromey at sourceware dot org]

https://sourceware.org/bugzilla/show_bug.cgi?id=20991

--- Comment #14 from Tom Tromey <tromey at sourceware dot org> ---
> Yeah.  I suppose gcc's is nicer this way, you can specify the
> precision.

It occurs to me, though, that not many things in gdb are using
"chained" expressions.  Normally we'd unpack a value to a GMP,
operate on it, then put it back into a value.  So, frequently,
we wouldn't actually have to worry about the size of intermediates

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[Bug exp/20991] __int128 type support

[pedro at palves dot net]

https://sourceware.org/bugzilla/show_bug.cgi?id=20991

--- Comment #15 from Pedro Alves <pedro at palves dot net> ---
That may be true.  If we can make valarith.c:scalar_binop work for any
kind of fixed-precision type instead of doing host arithmetic on LONGEST, with
the precision being a runtime property, then we would get most of value
arithmetic done for all types, including types wider than 128 bits when they
come.

It still seems to me though like if we need to implement the fixed-precision
logic, we might as well consider factoring it out to an integer class.  That
type may be based on wide-int, some other integer template (there are plenty
such templates around we could borrow), or a wrapper around GMP (or a
fixed-precision wrapper around our C++ GMP infinite-precision wrapper).

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[Bug exp/20991] __int128 type support

[tromey at sourceware dot org]

https://sourceware.org/bugzilla/show_bug.cgi?id=20991

--- Comment #16 from Tom Tromey <tromey at sourceware dot org> ---
Yeah.  I even considered just writing our own.

Monday or so I'll push my WIP patch to add wide-int to the tree
and you can see what it looks like.  A few hacks were needed,
though nothing too serious.  Mostly I couldn't be bothered to
figure out how all the classes work.

The main attraction of GMP is we already have it, and I recently
added a few operators and such.

For constants and values in type properties we can either just
store the number on some obstack, or use LEB.  The latter can
be nice since we can sometimes just use a pointer directly into
the DWARF data.

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[Bug exp/20991] __int128 type support

[tromey at sourceware dot org]

https://sourceware.org/bugzilla/show_bug.cgi?id=20991

--- Comment #17 from Tom Tromey <tromey at sourceware dot org> ---
(In reply to Tom Tromey from comment #16)

> Monday or so I'll push my WIP patch to add wide-int to the tree
> and you can see what it looks like

It is submit/wide-int-hacks in my github

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[Bug exp/20991] __int128 type support

[tromey at sourceware dot org]

https://sourceware.org/bugzilla/show_bug.cgi?id=20991

--- Comment #18 from Tom Tromey <tromey at sourceware dot org> ---
See also submit/pr-20991-more-gmp for the WIP.

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[Bug exp/20991] __int128 type support

[tromey at sourceware dot org]

https://sourceware.org/bugzilla/show_bug.cgi?id=20991

Tom Tromey <tromey at sourceware dot org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Blocks|21185                       |
         Depends on|                            |21185


Referenced Bugs:

https://sourceware.org/bugzilla/show_bug.cgi?id=21185
[Bug 21185] add i128 and u128 support to rust lexer and parser
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[Bug exp/20991] __int128 type support

[tromey at sourceware dot org]

https://sourceware.org/bugzilla/show_bug.cgi?id=20991
Bug 20991 depends on bug 21185, which changed state.

Bug 21185 Summary: add i128 and u128 support to rust lexer and parser
https://sourceware.org/bugzilla/show_bug.cgi?id=21185

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|RESOLVED                    |REOPENED
         Resolution|DUPLICATE                   |---

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[Bug exp/20991] __int128 type support

[tromey at sourceware dot org]

https://sourceware.org/bugzilla/show_bug.cgi?id=20991

Tom Tromey <tromey at sourceware dot org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
         Depends on|                            |19423


Referenced Bugs:

https://sourceware.org/bugzilla/show_bug.cgi?id=19423
[Bug 19423] __int128  conversion towards "const __int128 &" should be allowed
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[Bug exp/20991] __int128 type support

[tromey at sourceware dot org]

https://sourceware.org/bugzilla/show_bug.cgi?id=20991

Tom Tromey <tromey at sourceware dot org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
         Depends on|                            |30188


Referenced Bugs:

https://sourceware.org/bugzilla/show_bug.cgi?id=30188
[Bug 30188] add 128-bit integer support to Ada lexer and parser
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[Bug exp/20991] __int128 type support

[tromey at sourceware dot org]

https://sourceware.org/bugzilla/show_bug.cgi?id=20991

Tom Tromey <tromey at sourceware dot org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
         Depends on|                            |30189


Referenced Bugs:

https://sourceware.org/bugzilla/show_bug.cgi?id=30189
[Bug 30189] add 128-bit integer support to C lexer and parser
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[Bug exp/20991] __int128 type support

[tromey at sourceware dot org]

https://sourceware.org/bugzilla/show_bug.cgi?id=20991

Tom Tromey <tromey at sourceware dot org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
         Depends on|                            |30190


Referenced Bugs:

https://sourceware.org/bugzilla/show_bug.cgi?id=30190
[Bug 30190] Allow 128-bit arithemetic on value
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[Bug exp/20991] __int128 type support

[tromey at sourceware dot org]

https://sourceware.org/bugzilla/show_bug.cgi?id=20991

Tom Tromey <tromey at sourceware dot org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
         Depends on|                            |30191


Referenced Bugs:

https://sourceware.org/bugzilla/show_bug.cgi?id=30191
[Bug 30191] allow 128-bit types in properties
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[Bug exp/20991] [meta] __int128 type support

[tromey at sourceware dot org]

https://sourceware.org/bugzilla/show_bug.cgi?id=20991

Tom Tromey <tromey at sourceware dot org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
            Summary|__int128 type support       |[meta] __int128 type
                   |                            |support

--- Comment #19 from Tom Tromey <tromey at sourceware dot org> ---
(In reply to Tom Tromey from comment #8)

> Also it seems like there are multiple parts to this bug.
> Perhaps we should treat them individually...

I filed new bugs and I'm turning this into a meta bug.

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[Bug exp/20991] [meta] __int128 type support

[tromey at sourceware dot org]

https://sourceware.org/bugzilla/show_bug.cgi?id=20991
Bug 20991 depends on bug 30190, which changed state.

Bug 30190 Summary: Allow 128-bit arithemetic on value
https://sourceware.org/bugzilla/show_bug.cgi?id=30190

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

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[Bug exp/20991] [meta] __int128 type support

[tromey at sourceware dot org]

https://sourceware.org/bugzilla/show_bug.cgi?id=20991
Bug 20991 depends on bug 21185, which changed state.

Bug 21185 Summary: add i128 and u128 support to rust lexer and parser
https://sourceware.org/bugzilla/show_bug.cgi?id=21185

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

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[Bug exp/20991] [meta] __int128 type support

[tromey at sourceware dot org]

https://sourceware.org/bugzilla/show_bug.cgi?id=20991
Bug 20991 depends on bug 30188, which changed state.

Bug 30188 Summary: add 128-bit integer support to Ada lexer and parser
https://sourceware.org/bugzilla/show_bug.cgi?id=30188

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

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[Bug exp/20991] [meta] __int128 type support

[ssbssa at sourceware dot org]

https://sourceware.org/bugzilla/show_bug.cgi?id=20991
Bug 20991 depends on bug 19423, which changed state.

Bug 19423 Summary: __int128  conversion towards "const __int128 &" should be allowed
https://sourceware.org/bugzilla/show_bug.cgi?id=19423

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

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