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From: Simon Marchi <simark@simark.ca>
To: Tom Tromey <tom@tromey.com>,
	Simon Marchi via Gdb-patches <gdb-patches@sourceware.org>
Cc: Simon Marchi <simon.marchi@efficios.com>
Subject: Re: [PATCH v2 23/42] Add dwarf2_per_objfile to dwarf_expr_context and dwarf2_frame_cache
Date: Wed, 27 May 2020 21:44:34 -0400	[thread overview]
Message-ID: <87fe5955-3645-6f3a-6aeb-29df3d7ac585@simark.ca> (raw)
In-Reply-To: <66566187-024e-9a5e-9628-2f8e0cea7279@simark.ca>

On 2020-05-25 3:50 p.m., Simon Marchi wrote:
> On 2020-05-22 5:04 p.m., Tom Tromey wrote:
>>>>>>> "Simon" == Simon Marchi via Gdb-patches <gdb-patches@sourceware.org> writes:
>>
>> Simon> *Note*, there's one spot I'm particularly unsure about.  In
>> Simon> dwarf_evaluate_loc_desc::push_dwarf_reg_entry_value, we would save and
>> Simon> overwrite the offset value in the context, along with a bunch of other
>> Simon> state.  This is because we might be about to evaluate something in a
>> Simon> different CU that the current one.  If the two CUs are in the same
>> Simon> objfile, then the text_offset is the same, as it's a property of the
>> Simon> objfile.  However, if the two CUs are possibly in different objfiles,
>> Simon> then it means the text_offsets are different.  It would also mean we
>> Simon> would need to save and restore the dwarf2_per_objfile in the context.
>> Simon> Is that even possible?
>>
>> Unfortunately I don't know for sure.
>> However, call_site_for_pc doesn't distinguish between objfiles.  So, I
>> suppose I would assume it is possible.
>>
>> Tom
> 
> In practice, I'm not sure how that can happen.  Can DWARF info in an objfile
> refer to the DWARF info in another objfile?  Can there be a subprogram described
> in one and a call site of that subprogram described in another objfile?  If we
> are quite sure it can't happen, I would rather not include code for it, that's
> just unnecessary complexity.
> 
> A further patch (28/42) happens to tie call sites with an objfile, and adds a
> gdb_assert here making sure that the call site's objfile is the same as the
> callee's objfile.
> 
> So I would propose to leave that gdb_assert there, if we are wrong then we'll
> fix that function.

So it turns out that it wasn't there for nothing!  Call sites can refer to another
objfile in some occasions.  See the follow up in this thread:

https://sourceware.org/pipermail/gdb-patches/2020-May/169077.html

Simon

  reply	other threads:[~2020-05-28  1:44 UTC|newest]

Thread overview: 92+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-05-12 21:08 [PATCH v2 00/42] Share DWARF partial symtabs between objfiles Simon Marchi
2020-05-12 21:08 ` [PATCH v2 01/42] Introduce dwarf2_per_objfile::obstack Simon Marchi
2020-05-12 21:08 ` [PATCH v2 02/42] Add "objfile" parameter to two partial_symtab methods Simon Marchi
2020-05-12 21:08 ` [PATCH v2 03/42] Add dwarf2_per_cu_data::index Simon Marchi
2020-05-12 21:08 ` [PATCH v2 04/42] Add dwarf2_per_objfile member to DWARF batons Simon Marchi
2020-05-12 21:08 ` [PATCH v2 05/42] Split dwarf2_per_objfile into dwarf2_per_objfile and dwarf2_per_bfd Simon Marchi
2020-05-12 21:08 ` [PATCH v2 06/42] Remove symtab links from dwarf2_psymtab and dwarf2_per_cu_quick_data Simon Marchi
2020-05-12 21:08 ` [PATCH v2 07/42] Move die_type_hash to dwarf2_per_objfile Simon Marchi
2020-05-12 21:08 ` [PATCH v2 08/42] Add dwarf2_per_objfile field to dwarf2_cu Simon Marchi
2020-05-12 21:08 ` [PATCH v2 09/42] Remove reference to dwarf2_per_cu_data::dwarf2_per_objfile in dw2_do_instantiate_symtab Simon Marchi
2020-05-12 21:11 ` [PATCH v2 10/42] Remove dwarf2_cu->per_cu->dwarf2_per_objfile references Simon Marchi
2020-05-12 21:11 ` [PATCH v2 11/42] Add dwarf2_per_bfd field to dwarf2_per_cu_data Simon Marchi
2020-05-12 21:11 ` [PATCH v2 12/42] Make dwarf2_get_dwz_file take a dwarf2_per_bfd Simon Marchi
2020-05-12 21:11 ` [PATCH v2 13/42] Use bfd_get_filename instead of objfile_name in lookup_dwo_unit Simon Marchi
2020-05-12 21:11 ` [PATCH v2 14/42] Add dwarf2_per_objfile parameter to cutu_reader's constructors Simon Marchi
2020-05-12 21:11 ` [PATCH v2 15/42] Make queue_and_load_dwo_tu receive a dwarf2_cu Simon Marchi
2020-05-22 20:45   ` Tom Tromey
2020-05-25 19:10     ` Simon Marchi
2020-05-12 21:11 ` [PATCH v2 16/42] Remove dwarf2_per_cu_data::dwarf2_per_objfile reference in cutu_reader::keep Simon Marchi
2020-05-12 21:11 ` [PATCH v2 17/42] Add dwarf2_per_objfile parameter to create_partial_symtab Simon Marchi
2020-05-12 21:11 ` [PATCH v2 18/42] Add dwarf2_per_objfile parameter to recursively_compute_inclusions Simon Marchi
2020-05-12 21:11 ` [PATCH v2 19/42] Add dwarf2_per_objfile parameter to process_full_{comp, type}_unit Simon Marchi
2020-05-12 21:12 ` [PATCH v2 20/42] Pass dwarf2_cu objects to dwo-related functions, instead of dwarf2_per_cu_data Simon Marchi
2020-05-12 21:12 ` [PATCH v2 21/42] Remove reference to dwarf2_per_cu_data::dwarf2_per_objfile in queue_and_load_all_dwo_tus Simon Marchi
2020-05-12 21:12 ` [PATCH v2 22/42] Move int type methods out of dwarf2_per_cu_data Simon Marchi
2020-05-12 21:12 ` [PATCH v2 23/42] Add dwarf2_per_objfile to dwarf_expr_context and dwarf2_frame_cache Simon Marchi
2020-05-22 21:04   ` Tom Tromey
2020-05-25 19:50     ` Simon Marchi
2020-05-28  1:44       ` Simon Marchi [this message]
2020-05-12 21:12 ` [PATCH v2 24/42] Remove dwarf2_per_cu_data::text_offset Simon Marchi
2020-05-12 21:12 ` [PATCH v2 25/42] Add dwarf2_per_objfile parameter to dwarf2_read_addr_index Simon Marchi
2020-05-12 21:12 ` [PATCH v2 26/42] Add dwarf2_per_objfile parameter to allocate_piece_closure Simon Marchi
2020-05-12 21:12 ` [PATCH v2 27/42] Add dwarf2_per_objfile parameters to dwarf2_fetch_* functions Simon Marchi
2020-05-12 21:12 ` [PATCH v2 28/42] Remove dwarf2_per_cu_data::objfile () Simon Marchi
2020-05-27 16:27   ` Tom de Vries
2020-05-27 16:52     ` Tom de Vries
2020-05-27 20:03     ` Simon Marchi
2020-05-27 21:08       ` Tom de Vries
2020-05-27 21:55         ` Simon Marchi
2020-05-27 22:16           ` Simon Marchi
2020-05-28  2:00             ` Simon Marchi
2020-05-28 13:05               ` Tom de Vries
2020-05-28 15:33                 ` Simon Marchi
2020-05-28 16:24                   ` Christian Biesinger
2020-05-28 16:52                     ` Simon Marchi
2020-05-28 19:49                       ` Simon Marchi
2020-05-12 21:12 ` [PATCH v2 29/42] Add dwarf2_per_objfile parameter to free_one_cached_comp_unit Simon Marchi
2020-05-12 21:17 ` [PATCH v2 30/42] Add dwarf2_per_objfile parameter to get_die_type_at_offset Simon Marchi
2020-05-12 21:17 ` [PATCH v2 31/42] Remove leftover references to dwarf2_per_cu_data::dwarf2_per_objfile Simon Marchi
2020-05-12 21:17 ` [PATCH v2 32/42] Remove dwarf2_per_cu_data::dwarf2_per_objfile Simon Marchi
2020-05-12 21:17 ` [PATCH v2 33/42] Split type_unit_group Simon Marchi
2020-05-13  9:54   ` Tom de Vries
2020-05-13 15:06     ` Simon Marchi
2020-05-12 21:17 ` [PATCH v2 34/42] Move signatured_type::type to unshareable object Simon Marchi
2020-05-12 21:17 ` [PATCH v2 35/42] Pass dwarf2_per_bfd instead of dwarf2_per_objfile to some index-related functions Simon Marchi
2020-05-12 21:17 ` [PATCH v2 36/42] Pass dwarf2_cu to process_full_{comp,type}_unit Simon Marchi
2020-05-12 21:17 ` [PATCH v2 37/42] Make load_cu return the loaded dwarf2_cu Simon Marchi
2020-05-12 21:17 ` [PATCH v2 38/42] Add comp_unit_head to dwarf2_per_cu_data Simon Marchi
2020-05-12 21:17 ` [PATCH v2 39/42] Pass existing_cu object to cutu_reader Simon Marchi
2020-05-22 20:57   ` Tom Tromey
2020-05-25 19:10     ` Simon Marchi
2020-05-12 21:18 ` [PATCH v2 40/42] Replace dwarf2_per_cu_data::cu backlink with per-objfile map Simon Marchi
2020-05-12 21:18 ` [PATCH v2 41/42] Make mapped_debug_names independent of objfile Simon Marchi
2020-05-22 21:01   ` Tom Tromey
2020-05-25 19:53     ` Simon Marchi
2020-05-12 21:18 ` [PATCH v2 42/42] Share DWARF partial symtabs Simon Marchi
2020-05-13 10:17 ` [PATCH v2 00/42] Share DWARF partial symtabs between objfiles Tom de Vries
2020-05-13 15:46   ` Simon Marchi
2020-05-22 21:02     ` Tom Tromey
2020-05-25 19:53       ` Simon Marchi
2020-05-13 14:52 ` Simon Marchi
2020-05-22 21:07 ` Tom Tromey
2020-05-23 12:24   ` Pedro Alves
2020-05-25 19:56     ` Simon Marchi
2020-05-26 11:17       ` Pedro Alves
2020-05-26 15:35         ` Simon Marchi
2020-05-26 21:34           ` Simon Marchi
2020-05-27  5:08             ` Simon Marchi
2020-05-27 14:53               ` Simon Marchi
2020-05-27 15:51                 ` Simon Marchi
2020-05-29 10:23                   ` Tom de Vries
2020-05-29 12:55                     ` Tom de Vries
2020-05-31  4:16                     ` Simon Marchi
2020-05-31 14:22                       ` Tom de Vries
2020-06-02 21:27                         ` Simon Marchi
2020-06-04 17:55                           ` Tom de Vries
2020-06-04 18:04                             ` Simon Marchi
2020-06-10  3:43                               ` Simon Marchi
2020-06-12  3:25                                 ` Tom Tromey
2020-05-27 14:50 ` [PATCH v2 41.5/42] Move line_header_hash to dwarf2_per_objfile Simon Marchi
2020-05-27 15:07   ` Tom Tromey
2020-05-27 15:10     ` Simon Marchi

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