Commit Graph

207 Commits

Author SHA1 Message Date
Tom Tromey
7d00ffecd2 Lazily compute partial DIE name
Currently the name of a partial DIE is computed eagerly.  However, the
name is not always needed.  This patch changes partial DIEs to compute
their name lazily, improving performance by avoiding unnecessary name
computations.

The run previous to this had times of (see the first patch in the
series for an explanation):

gdb    1.88
libxul 2.11
Ada    2.60

This patch improves the times to:

gdb    1.69
libxul 2.02
Ada    2.52

gdb/ChangeLog
2020-05-27  Tom Tromey  <tromey@adacore.com>

	* dwarf2/read.c (struct partial_die_info) <name>: Declare new
	method.
	<canonical_name>: New member.
	<raw_name>: Rename from "name".
	(partial_die_info): Initialize canonical_name.
	(scan_partial_symbols): Check raw_name.
	(partial_die_parent_scope, partial_die_full_name)
	(add_partial_symbol, add_partial_subprogram)
	(add_partial_enumeration, load_partial_dies): Use "name" method.
	(partial_die_info::name): New method.
	(partial_die_info::read, guess_partial_die_structure_name)
	(partial_die_info::fixup): Update.
2020-05-27 11:48:19 -06:00
Tom Tromey
697bba1827 Attribute method inlining
This inlines a couple of methods on struct attribute, improving the
performance of DWARF partial symbol reading.  These methods were
discovered as hot spots using callgrind.

For this patch, and for all the patches in this series, I tested gdb's
performance on three programs:

1. gdb itself -- I built gdb and copied it to /tmp, ensuring that the
   same version was used in all tests.

2. The system libxul.so, the main library of Firefox.  I installed the
   separate debuginfo and ensured that gdb read it.

3. A large-ish Ada program that I happen to have.

I ran gdb 10 times like:

	  /bin/time -f %e \
		    ./gdb/gdb --data-directory ./gdb/data-directory -nx \
		    -iex 'set debug-file-directory /usr/lib/debug' \
		    -batch $X

... where $X was the test executable.  Then I computed the mean time.
This was all done with a standard (-g -O2) build of gdb.

The baseline times were

gdb    1.90
libxul 2.12
Ada    2.61

This patch brings the numbers down to

gdb    1.88
libxul 2.11
Ada    2.60

Not a huge change, but still visible in the results.

gdb/ChangeLog
2020-05-27  Tom Tromey  <tromey@adacore.com>

	* dwarf2/attribute.h (struct attribute) <form_is_ref>: Inline.
	<get_ref_die_offset>: Inline.
	<get_ref_die_offset_complaint>: New method.
	* dwarf2/attribute.c (attribute::form_is_ref): Move to header.
	(attribute::get_ref_die_offset_complaint): Rename from
	get_ref_die_offset.  Just issue complaint.
2020-05-27 11:48:18 -06:00
Tom Tromey
17ee85fc2a Share DWARF partial symtabs
This changes the DWARF reader to share partial symtabs (or indices if
they are available) across objfiles.  This has a few parts.

* If multiple objfiles backed by the same BFD can share partial symtabs
  (see below), a single dwarf2_per_bfd is created.  It is stored in the
  per-bfd `dwarf2_per_bfd_bfd_data_key` registry.  Multiple
  dwarf2_per_objfile objects will point to the same instance.  The
  lifetime of these dwarf2_per_bfd objects is naturally handled.  When
  all the objfiles using the BFD are destroyed, the BFD's refount drops
  to 0, which triggers the removal of the corresponding dwarf2_per_bfd
  object from the registry and its destruction.

* If multiple objfiles backed by the same BFD can't share partial
  symtabs (see below), one dwarf2_per_bfd object is created for each
  objfile.  Each dwarf2_per_objfile will point to their own instance of
  dwarf2_per_bfd.  These instances of dwarf2_per_bfd are kept in a
  per-objfile registry, meaning that when the objfile gets destroyed,
  the dwarf2_per_bfd instance gets destroyed as well.

* objfile::partial_symtabs is changed to be a shared_ptr again.  This
  lets us stash a second reference in dwarf2_per_bfd; if the DWARF
  data is being shared, we can simply copy this value to the new
  objfile.

* Two dwarf2_per_objfile objects backed by the same BFD may share a
  dwarf2_per_bfd instance if:

  * No other symbol reader has found symbols, and
  * No BFD section rqeuires relocation

gdb/ChangeLog:

YYYY-MM-DD  Tom Tromey  <tom@tromey.com>
YYYY-MM-DD  Simon Marchi  <simon.marchi@efficios.com>

	* objfiles.h (struct objfile) <partial_symtabs>: Now a
	shared_ptr.
	* dwarf2/read.h (struct dwarf2_per_objfile) <partial_symtabs>: New
	member.
	* dwarf2/read.c (dwarf2_per_bfd_bfd_data_key,
	dwarf2_per_bfd_objfile_data_key>: New globals.
	(dwarf2_has_info): Use shared dwarf2_per_bfd if possible.
	(dwarf2_get_section_info): Use get_dwarf2_per_objfile.
	(dwarf2_initialize_objfile): Consider cases where per_bfd can be
	shared.
	(dwarf2_build_psymtabs): Set objfile::partial_symtabs and
	short-circuit when sharing.
	(dwarf2_build_psymtabs): Set dwarf2_per_objfile::partial_symtabs.
	(dwarf2_psymtab::expand_psymtab): Use free_cached_comp_units.

Change-Id: I868c64448589102ab8cbb8f06c31a8de50a14004
2020-05-27 11:20:15 -04:00
Simon Marchi
39b16f87f7 Move line_header_hash to dwarf2_per_objfile
The `line_header_hash` field of `struct dwarf2_per_bfd` contains some
`struct line_header` objects.  A `struct line_header` objects contains
some `file_entry` objects.  A `file_entry` object contains a pointer to
the `symtab` object created from it.  The `line_header_hash` is
therefore ultimately objfile-dependent and can't be shared as-is between
objfiles.

Move it from `dwarf2_per_bfd` to `dwarf2_per_objfile`.

gdb/ChangeLog:

	* dwarf2/read.h (struct dwarf2_per_bfd) <line_header_hash>: Move
	to...
	(struct dwarf2_per_objfile) <line_header_hash>: ... here.
	* dwarf2/read.c (handle_DW_AT_stmt_list): Update.

Change-Id: I8d2ee04df4f4847c2db99061fc976c35af98ac71
2020-05-27 11:19:41 -04:00
Simon Marchi
fcf23d5b65 Make mapped_debug_names independent of objfile
mapped_debug_names currently has a dwarf2_per_objfile field.  Since we
want it to become objfile-independent, this field must be removed.

This patch removes it, and then arranges for all methods that needed it
to accept a dwarf2_per_objfile parameter.  This trickles down at various
places, like the dw2_debug_names_iterator type.

Ultimately, the objfile only seems to be needed because we might need to
read a string from the string section.  For that, we might need to read
in the section, and if it's a relocatable section, the objfile is needed
in order to do the relocation.  This pattern happens often (that we to
pass an objfile only because a section might be read).  I think it's a
bit ugly, but I don't have a good alternative right now.

gdb/ChangeLog:

	* dwarf2/read.c (struct mapped_index_base) <symbol_name_at,
	build_name_components, find_name_components_bounds>:
	Add per_objfile parameter.
	(struct mapped_index) <symbol_name_at>: Likewise.
	(struct mapped_debug_names): Remove constructor.
	<dwarf2_per_objfile>: Remove field.
	<namei_to_name, symbol_name_at>: Add per_objfile parameter.
	(mapped_index_base::find_name_components_bounds,
	mapped_index_base::build_name_components,
	dw2_expand_symtabs_matching_symbol): Likewise.
	(class mock_mapped_index) <symbol_name_at>: Likewise.
	(check_match): Likewise.
	(check_find_bounds_finds): Likewise.
	(test_mapped_index_find_name_component_bounds): Update.
	(CHECK_MATCH): Update.
	(dw2_expand_symtabs_matching): Update.
	(class dw2_debug_names_iterator) <dw2_debug_names_iterator>: Add
	per_objfile parameter.
	<find_vec_in_debug_names>: Likewise.
	<m_per_objfile>: New field.
	(mapped_debug_names::namei_to_name): Add dwarf2_per_objfile
	parameter.
	(dw2_debug_names_iterator::find_vec_in_debug_names): Likewise.
	(dw2_debug_names_iterator::next): Update.
	(dw2_debug_names_lookup_symbol): Update.
	(dw2_debug_names_expand_symtabs_for_function): Update.
	(dw2_debug_names_map_matching_symbols): Update.
	(dw2_debug_names_expand_symtabs_matching): Update.
	(dwarf2_read_debug_names): Update.

Change-Id: I00ee0d939390d353442675c7d400a261307c57a1
2020-05-27 11:19:41 -04:00
Simon Marchi
7188ed02d2 Replace dwarf2_per_cu_data::cu backlink with per-objfile map
The dwarf2_per_cu_data type is going to become objfile-independent,
while the dwarf2_cu type will stay object-dependent.  This patch removes
the backlink from dwarf2_per_cu_data to dwarf2_cu, in favor of the
dwarf2_per_objfile::m_dwarf2_cus map.  It maps dwarf2_per_cu_data
objects to the corresponding dwarf2_cu objects for this objfile.  If a
CU has been read in in the context of this objfile, then an entry will
be present in the map.

The dwarf2_cu objects that are read in are currently kept in a linked
list rooted in the dwarf2_per_bfd.  Except that the dwarf2_cu objects
are not simply linked together, they are interleaved with their
corresponding dwarf2_per_cu_data objects.  So if we have CUs A and B
read in, the dwarf2_per_bfd::read_in_chain will point to a chain like
this (DPCD == dwarf2_per_cu_data, DC == dwarf2_cu):

 DPCD A -> DC A -> DPCD B -> DC B

Obviously, this can't stay as is, since a same CU can be read in for an
objfile but not read in for another objfile sharing the same BFD, and
the dwarf2_per_cu_data::cu link is removed.   This is all replaced by
the dwarf2_per_objfile::m_dwarf2_cus map.

gdb/ChangeLog:

	* dwarf2/read.h (struct dwarf2_cu): Forward-declare.
	(struct dwarf2_per_bfd) <free_cached_comp_units>: Remove,
	move to dwarf2_per_objfile.
	<read_in_chain>: Remove.
	(struct dwarf2_per_objfile) <get_cu, set_cu, remove_cu,
	remove_all_cus, age_comp_units>: New methods.
	<m_dwarf2_cus>: New member.
	(struct dwarf2_per_cu_data) <cu>: Remove.
	* dwarf2/read.c (struct dwarf2_cu) <read_in_chain>: Remove.
	(age_cached_comp_units, free_one_cached_comp_unit): Remove,
	moved to methods of dwarf2_per_objfile.
	(dwarf2_clear_marks): Remove.
	(dwarf2_queue_item::~dwarf2_queue_item): Update.
	(dwarf2_per_bfd::~dwarf2_per_bfd): Don't free dwarf2_cus.
	(dwarf2_per_bfd::free_cached_comp_units): Remove.
	(dwarf2_per_objfile::remove_all_cus): New.
	(class free_cached_comp_units) <~free_cached_comp_units>:
	Update.
	(load_cu): Update.
	(dw2_do_instantiate_symtab): Adjust.
	(fill_in_sig_entry_from_dwo_entry): Adjust.
	(cutu_reader::init_tu_and_read_dwo_dies): Update.
	(cutu_reader::cutu_reader): Likewise.
	(cutu_reader::keep): Use dwarf2_per_objfile::set_cu.
	(cutu_reader::cutu_reader): Use dwarf2_per_objfile::get_cu.
	(process_psymtab_comp_unit): Use dwarf2_per_objfile::remove_cu
	and dwarf2_per_objfile::age_comp_units.
	(load_partial_comp_unit): Update.
	(maybe_queue_comp_unit): Use dwarf2_per_objfile::get_cu.
	(process_queue): Likewise.
	(find_partial_die): Use dwarf2_per_objfile::get_cu instead of cu
	backlink.
	(dwarf2_read_addr_index): Likewise.
	(follow_die_offset): Likewise.
	(dwarf2_fetch_die_loc_sect_off): Likewise.
	(dwarf2_fetch_constant_bytes): Likewise.
	(dwarf2_fetch_die_type_sect_off): Likewise.
	(follow_die_sig_1): Likewise.
	(load_full_type_unit): Likewise.
	(read_signatured_type): Likewise.
	(dwarf2_cu::dwarf2_cu): Don't set cu field.
	(dwarf2_cu::~dwarf2_cu): Remove.
	(dwarf2_per_objfile::get_cu): New.
	(dwarf2_per_objfile::set_cu): New.
	(age_cached_comp_units): Rename to...
	(dwarf2_per_objfile::age_comp_units): ... this.  Adjust
	to std::unordered_map.
	(free_one_cached_comp_unit): Rename to...
	(dwarf2_per_objfile::remove_cu): ... this.  Adjust
	to std::unordered_map.
	(dwarf2_per_objfile::~dwarf2_per_objfile): New.
	(dwarf2_mark_helper): Use dwarf2_per_objfile::get_cu, expect
	a dwarf2_per_objfile in data.
	(dwarf2_mark): Pass dwarf2_per_objfile in data to htab_traverse.
	(dwarf2_clear_marks): Remove.

Change-Id: Ia33ac71c79b2de4710569008e22a6563a1505cde
2020-05-27 11:19:40 -04:00
Simon Marchi
2e6711003b Pass existing_cu object to cutu_reader
It is possible, seemingly for a special case described in
find_partial_die, for cutu_reader to re-use an existing dwarf2_cu
instead of creating a new one.  This happens when running this test, for
example:

    make check TESTS="gdb.dwarf2/fission-reread.exp"

Right now the, `use_existing_cu` flag tells cutu_reader to use the
dwarf2_cu object at dwarf2_per_cu_data::cu.  However, we'll remove that
field, so we need to find another solution.

This situation arises when some caller up the stack has already created
the dwarf2_cu to read a dwarf2_per_cu_data, but needs to re-read it with
some other parameters.  Therefore, it's possible to just have that
caller pass down the dwarf2_cu object to use as a `existing_cu`
parameter.  If `existing_cu` is NULL, it tells cutu_reader that it needs
to instantiate a new one.

gdb/ChangeLog:

	* dwarf2/read.c (class cutu_reader) <cutu_reader>: Replace
	`int use_existing_cu` parameter with `dwarf2_cu *existing_cu`.
	(init_tu_and_read_dwo_dies): Likewise.
	(cutu_reader::init_tu_and_read_dwo_dies): Likewise.
	(cutu_reader::cutu_reader): Likewise.
	(load_partial_comp_unit): Likewise.
	(process_psymtab_comp_unit): Update.
	(build_type_psymtabs_1): Update.
	(process_skeletonless_type_unit): Update.
	(load_full_comp_unit): Update.
	(find_partial_die): Update.
	(dwarf2_read_addr_index): Update.
	(read_signatured_type): Update.

Change-Id: Id03e3bc3de3cf99d9e4b4080ad83b029c93bf434
2020-05-27 11:19:40 -04:00
Simon Marchi
2e6a9f7959 Add comp_unit_head to dwarf2_per_cu_data
The per_cu_header_read_in function allows obtaining a filled
comp_unit_head object for a given dwarf2_per_cu_data object.  If a
dwarf2_cu object exists for this dwarf2_per_cu_data, then it just
returns a pointer to the comp_unit_head from that dwarf2_cu.  Otherwise,
it reads the header into a temporary buffer provided by the caller, and
returns a pointer to that.

Since the dwarf2_per_cu_data::cu link is going to be removed
(dwarf2_per_cu_data will become objfile-independent while dwarf2_cu
stays objfile-dependent), we cannot rely anymore on returning the header
from the dwarf2_cu object.

The not too complex solution implemented by this patch is to keep a copy
of the header in the dwarf2_per_cu_data object, independent from the
copy in dwarf2_cu.  The new copy is only used in the addr_size,
offset_size and ref_addr_size methods of dwarf2_per_cu_data.

There's nothing intrinsic to the comp_unit_head object that prevents it
to be shared between two dwarf2_cu objects (belonging to different
objfiles) representing the same CU.  In other words, I think we could
eventually get rid of the copy in dwarf2_cu to only keep the one in
dwarf2_per_cu_data.  It is not trivial, however, so I have decided not
to do it for the moment.

gdb/ChangeLog:

	* dwarf2/read.h (struct dwarf2_per_cu_data) <m_header,
	m_header_read_in>: New fields.
	<get_header>: New method.
	* dwarf2/read.c (per_cu_header_read_in): Remove.
	(dwarf2_per_cu_data::get_header): New.
	(dwarf2_per_cu_data::addr_size): Update.
	(dwarf2_per_cu_data::offset_size): Update.
	(dwarf2_per_cu_data::ref_addr_size): Update.

Change-Id: Id7541fca7562843eba110ece21c4df38d45fca23
2020-05-27 11:19:40 -04:00
Simon Marchi
1b555f1747 Make load_cu return the loaded dwarf2_cu
In a subsequent patch, the dwarf2_per_cu_data::cu link will be removed.
dwarf2_cu objects will instead need to be looked up from a per-objfile
map, using the dwarf2_per_cu_data object as the key.

To make it easier for some callers, this patch makes load_cu return the
dwarf2_cu it creates.  If the caller needs to use the created dwarf2_cu,
it will have it available right away, rather than having to do a map
lookup.

At the same time, this allows changing queue_and_load_all_dwo_tus to
take a dwarf2_cu instead of a dwarf2_per_cu_data.

gdb/ChangeLog:

	* dwarf2/read.c (load_cu): Return dwarf2_cu.
	(dw2_do_instantiate_symtab): Update.
	(queue_and_load_all_dwo_tus): Change parameter from
	dwarf2_per_cu_data to dwarf2_cu.
	(dwarf2_fetch_die_loc_sect_off): Update.
	(dwarf2_fetch_constant_bytes): Update.
	(dwarf2_fetch_die_type_sect_off): Update.

Change-Id: I8a04c5d1b8cc661b8203f97999258ba8e04e1765
2020-05-27 11:19:40 -04:00
Simon Marchi
8fc0b21da6 Pass dwarf2_cu to process_full_{comp,type}_unit
These two functions work on a dwarf2_cu.  It is currently obtained from
the per_cu->cu link, which we want to remove.  Make them accept the
dwarf2_cu directly as a parameter.  This moves the per_cu->cu references
one level up, but that one will be removed too in a subsequent patch.

gdb/ChangeLog:

	* dwarf2/read.c (process_full_comp_unit,
	process_full_type_unit): Remove per_cu, per_objfile paramters.
	Add dwarf2_cu parameter.
	(process_queue): Update.

Change-Id: I1027d36986073ac991e198e06f9d51341dc19c6e
2020-05-27 11:19:40 -04:00
Simon Marchi
168c9250f2 Pass dwarf2_per_bfd instead of dwarf2_per_objfile to some index-related functions
All these functions actually only need to receive a dwarf2_per_bfd, pass
that instead of dwarf2_per_objfile.

gdb/ChangeLog:

	* dwarf2/read.c (create_cu_from_index_list): Replace
	dwarf2_per_objfile parameter with dwarf2_per_bfd.
	(create_cus_from_index_list): Likewise.
	(create_cus_from_index): Likewise.
	(create_signatured_type_table_from_index): Likewise.
	(create_cus_from_debug_names_list): Likewise.
	(create_cus_from_debug_names): Likewise.
	(dwarf2_read_gdb_index): Update.
	(dwarf2_read_debug_names): Update.

Change-Id: I8cd7dc04bf815723a48745e7e9b283663dccc1ac
2020-05-27 11:19:40 -04:00
Tom Tromey
e286671bf9 Move signatured_type::type to unshareable object
signatured_type has a link to the "struct type".  However, types are
inherently objfile-specific, so once sharing is implemented, this will
be incorrect.

This patch moves the type to a new map in the DWARF unshareable
object.

gdb/ChangeLog:

YYYY-MM-DD  Tom Tromey  <tom@tromey.com>
YYYY-MM-DD  Simon Marchi  <simon.marchi@efficios.com>

	* dwarf2/read.h (struct dwarf2_per_objfile)
	<get_type_for_signatured_type, set_type_for_signatured_type>:
	New methods.
	<m_type_map>: New member.
	(struct signatured_type) <type>: Remove.
	* dwarf2/read.c
	(dwarf2_per_objfile::get_type_for_signatured_type,
	dwarf2_per_objfile::set_type_for_signatured_type): New.
	(get_signatured_type): Use new methods.

Change-Id: I765ae3c43fae1064f51ced352167a57638609f02
2020-05-27 11:19:35 -04:00
Tom Tromey
8adb84872b Split type_unit_group
type_unit_group has links to the compunit_symtab and other symtabs.
However, once this object is shared across objfiles, this will no
longer be ok.

This patch introduces a new type_unit_group_unshareable and arranges to
store a map from type unit groups to type_unit_group_unshareable objects
in dwarf2_per_objfile.

gdb/ChangeLog:

YYYY-MM-DD  Tom Tromey  <tom@tromey.com>
YYYY-MM-DD  Simon Marchi  <simon.marchi@efficios.com>

	* dwarf2/read.h (struct type_unit_group_unshareable): New.
	(struct dwarf2_per_objfile) <type_units>: New member.
	<get_type_unit_group_unshareable>: New method.
	* dwarf2/read.c (struct type_unit_group) <compunit_symtab,
	num_symtabs, symtabs>: Remove; move to
	type_unit_group_unshareable.
	(dwarf2_per_objfile::get_type_unit_group_unshareable): New.
	(process_full_type_unit, dwarf2_cu::setup_type_unit_groups)
	(dwarf2_cu::setup_type_unit_groups): Use type_unit_group_unshareable.

Change-Id: I1fec2fab59e0ec40fee3614fc821172a469c0e41
2020-05-27 11:19:09 -04:00
Simon Marchi
127bbf4b50 Remove dwarf2_per_cu_data::dwarf2_per_objfile
Nothing references this field anymore, remove it.

gdb/ChangeLog:

	* dwarf2/read.h (struct dwarf2_per_cu_data):
	<dwarf2_per_objfile>: Remove.
	* dwarf2/read.c (create_cu_from_index_list): Don't assign
	dwarf2_per_objfile.
	(create_signatured_type_table_from_index): Likewise.
	(create_signatured_type_table_from_debug_names): Likewise.
	(create_debug_type_hash_table): Likewise.
	(fill_in_sig_entry_from_dwo_entry): Likewise.
	(create_type_unit_group): Likewise.
	(read_comp_units_from_section): Likewise.
	(create_cus_hash_table): Likewise.

Change-Id: Icf0b657a6beec953fe17cbe0fb2ae2c6e744d3ed
2020-05-27 11:15:58 -04:00
Simon Marchi
f6e649ddaf Remove leftover references to dwarf2_per_cu_data::dwarf2_per_objfile
This patch removes the remaining references to that field in obvious
ways (the same object is already available some other way in these
contexts).

gdb/ChangeLog:

	* dwarf2/read.c (process_psymtab_comp_unit): Remove reference to
	dwarf2_per_cu_data::dwarf2_per_objfile.
	(compute_compunit_symtab_includes): Likewise.
	(dwarf2_cu::start_symtab): Likewise.

Change-Id: I965700fa793d8457711a2d6ae448aaefd779eb96
2020-05-27 11:15:58 -04:00
Simon Marchi
aa66c37944 Add dwarf2_per_objfile parameter to get_die_type_at_offset
This allows removing some dwarf2_per_cu_data::dwarf2_per_objfile
references.

gdb/ChangeLog:

	* dwarf2/read.h (dwarf2_get_die_type): Add dwarf2_per_objfile
	parameter.
	* dwarf2/read.c (get_die_type_at_offset): Likewise.
	(read_namespace_alias): Update.
	(lookup_die_type): Update.
	(dwarf2_get_die_type): Add dwarf2_per_objfile parameter.
	* dwarf2/loc.c (class dwarf_evaluate_loc_desc) <get_base_type>:
	Update.
	(disassemble_dwarf_expression): Update.

Change-Id: Ibaf5b684cb0a8eb8f0b23e62bd0283c295410aa5
2020-05-27 11:15:58 -04:00
Simon Marchi
120ce1b5b2 Add dwarf2_per_objfile parameter to free_one_cached_comp_unit
This allows removing some references to
dwarf2_per_cu_data::dwarf2_per_objfile.

gdb/ChangeLog:

	* dwarf2/read.h (struct dwarf2_queue_item): Add
	dwarf2_per_objfile parameter, assign new parameter.
	<per_objfile>: New field.
	* dwarf2/read.c (free_one_cached_comp_unit): Add
	dwarf2_per_objfile parameter.
	(queue_comp_unit): Likewise.
	(dw2_do_instantiate_symtab): Update.
	(process_psymtab_comp_unit): Update.
	(maybe_queue_comp_unit): Add dwarf2_per_objfile parameter.
	(process_imported_unit_die): Update.
	(queue_and_load_dwo_tu): Update.
	(follow_die_offset): Update.
	(follow_die_sig_1): Update.

Change-Id: Ibb4a4ea28eeac5ebcbf73c0d2a13f9391e15c235
2020-05-27 11:15:57 -04:00
Simon Marchi
9f47c70716 Remove dwarf2_per_cu_data::objfile ()
Since dwarf2_per_cu_data objects are going to become
objfile-independent, the backlink from dwarf2_per_cu_data to one
particular objfile must be removed.  Instead, users of
dwarf2_per_cu_data that need an objfile must know from somewhere else in
the context of which objfile they are using this CU.

This also helps remove a dwarf2_per_cu_data::dwarf2_per_objfile
reference (from where the objfile was obtained).

Note that the dwarf2_per_cu_data::objfile method has a special case to
make sure to return the main objfile, if the objfile associated to the
dwarf2_per_cu_data is a separate debug objfile.  I don't really know if
this is necessary: I ignored that, and didn't see any regression when
testing with the various Dejagnu boards with separate debug info, so I
presume it wasn't needed.  If it turns out this was needed, then we can
have a helper method on the objfile type for that.

gdb/ChangeLog:

	* dwarf2/read.h (struct dwarf2_per_cu_data) <objfile>: Remove.
	* dwarf2/read.c (dwarf2_compute_name): Pass per_objfile down.
	(read_call_site_scope): Assign per_objfile.
	(dwarf2_per_cu_data::objfile): Remove.
	* gdbtypes.h (struct call_site) <per_objfile>: New member.
	* dwarf2/loc.h (dwarf2_evaluate_loc_desc): Add
	dwarf2_per_objfile parameter.
	* dwarf2/loc.c (dwarf2_evaluate_loc_desc_full): Add
	dwarf2_per_objfile parameter.
	(dwarf_expr_reg_to_entry_parameter): Add output
	dwarf2_per_objfile parameter.
	(locexpr_get_frame_base): Update.
	(class dwarf_evaluate_loc_desc) <get_tls_address>: Update.
	<push_dwarf_reg_entry_value>: Update.
	<call_site_to_target_addr>: Update.
	(dwarf_entry_parameter_to_value): Add dwarf2_per_objfile
	parameter.
	(value_of_dwarf_reg_entry): Update.
	(rw_pieced_value): Update.
	(indirect_synthetic_pointer): Update.
	(dwarf2_evaluate_property): Update.
	(dwarf2_loc_desc_get_symbol_read_needs): Add dwarf2_per_objfile
	parameter.
	(locexpr_read_variable): Update.
	(locexpr_get_symbol_read_needs): Update.
	(loclist_read_variable): Update.

Change-Id: Idb40d1a94995af305054d463967bb6ce11a08f25
2020-05-27 11:15:57 -04:00
Simon Marchi
14095eb326 Add dwarf2_per_objfile parameters to dwarf2_fetch_* functions
This allows removing dwarf2_per_cu_data references.

gdb/ChangeLog:

	* dwarf2/read.h (dwarf2_fetch_die_loc_sect_off,
	dwarf2_fetch_die_loc_cu_off, dwarf2_fetch_constant_bytes,
	dwarf2_fetch_die_type_sect_off): Add dwarf2_per_objfile
	parameter.
	* dwarf2/read.c (dwarf2_fetch_die_loc_sect_off,
	dwarf2_fetch_die_loc_cu_off, dwarf2_fetch_constant_bytes,
	dwarf2_fetch_die_type_sect_off): Add dwarf2_per_objfile
	parameter.
	* dwarf2/loc.c (indirect_synthetic_pointer, per_cu_dwarf_call,
	sect_variable_value): Add dwarf2_per_objfile parameter.
	(class dwarf_evaluate_loc_desc) <dwarf_call,
	dwarf_variable_value>: Update.
	(fetch_const_value_from_synthetic_pointer): Add
	dwarf2_per_objfile parameter.
	(fetch_const_value_from_synthetic_pointer): Update.
	(coerced_pieced_ref): Update.
	(class symbol_needs_eval_context) <dwarf_call,
	dwarf_variable_value>: Update.
	(dwarf2_compile_expr_to_ax): Update.

Change-Id: I07cf1806380633d0572304cea049a1fa5e9ea67f
2020-05-27 11:15:57 -04:00
Simon Marchi
3c3cd3d4d7 Add dwarf2_per_objfile parameter to allocate_piece_closure
This allows removing a dwarf2_per_cu_data::dwarf2_per_objfile reference.

gdb/ChangeLog:

	* dwarf2/loc.c (allocate_piece_closure): Add dwarf2_per_objfile
	parameter.
	(dwarf2_evaluate_loc_desc_full): Update.

Change-Id: Ic4a694a3fc763360a131ee4e3aaf5a5b4735c813
2020-05-27 11:15:57 -04:00
Simon Marchi
82ca3f5189 Add dwarf2_per_objfile parameter to dwarf2_read_addr_index
Pass it all the way from the symbol batons.  This allows removing a
dwarf2_per_cu_data::dwarf2_per_objfile reference.

gdb/ChangeLog:

	* dwarf2/read.h (dwarf2_read_addr_index): Add dwarf2_per_objfile
	parameter.
	* dwarf2/read.c (dwarf2_read_addr_index): Likewise.
	* dwarf2/loc.c (decode_debug_loclists_addresses): Add
	dwarf2_per_objfile parameter.
	(decode_debug_loc_dwo_addresses): Likewise.
	(dwarf2_find_location_expression): Update.
	(class dwarf_evaluate_loc_desc) <get_addr_index>: Update.
	(locexpr_describe_location_piece): Add dwarf2_per_objfile
	parameter.
	(disassemble_dwarf_expression): Add dwarf2_per_objfile
	parameter.
	(locexpr_describe_location_1): Likewise.
	(locexpr_describe_location): Update.

Change-Id: I8414755e41a87c92f96e408524cc7aaccf086cda
2020-05-27 11:15:57 -04:00
Simon Marchi
4b167ea1a0 Remove dwarf2_per_cu_data::text_offset
This method simply returns the text offset of the objfile associated to
the dwarf2_per_cu_data object.  Since dwarf2_per_cu_data objects are
going to become objfile-independent, we can't keep this method.  This
patch removes it.

Existing callers need to figure out the in the context of which objfile
this is being used, and call text_offset on it.  Typically, this comes
from a symbol baton, where we store the corresponding
dwarf2_per_objfile.

gdb/ChangeLog:

	* dwarf2/read.h (struct dwarf2_per_cu_data) <text_offset>:
	Remove.
	* dwarf2/read.c (dwarf2_per_cu_data::text_offset): Remove.
	* dwarf2/loc.c (dwarf2_find_location_expression): Update.
	(dwarf2_compile_property_to_c): Update.
	(dwarf2_compile_expr_to_ax): Add dwarf2_per_objfile parameter,
	use text offset from objfile.
	(locexpr_tracepoint_var_ref): Update.
	(locexpr_generate_c_location): Update.
	(loclist_describe_location): Update.
	(loclist_tracepoint_var_ref): Update.
	* dwarf2/compile.h (compile_dwarf_bounds_to_c): Add
	dwarf2_per_objfile parameter.
	* dwarf2/loc2c.c (do_compile_dwarf_expr_to_c): Likewise,
	use text offset from objfile.
	(compile_dwarf_expr_to_c): Add dwarf2_per_objfile parameter.

Change-Id: I56b01ba294733362a3562426a96d48ae051a776f
2020-05-27 11:15:57 -04:00
Simon Marchi
89b07335fe Add dwarf2_per_objfile to dwarf_expr_context and dwarf2_frame_cache
Evaluating DWARF expressions (such as location expressions) requires
knowing about the current objfile.  For example, it may call functions
like dwarf2_fetch_die_loc_sect_off, which currently obtain the
dwarf2_per_objfile object it needs from the dwarf2_per_cu_data object.
However, since we are going to remove this
dwarf2_per_cu_data::dwarf2_per_objfile link, these functions will need
to obtain the current dwarf2_per_objfile by parmeter.

If we go up the stack, we see that the DWARF expression contexts
(dwarf_expr_context and the classes that derive from it) need to store
the dwarf2_per_objfile, to be able to pass it to those functions that
will need it.

This patch adds a constructor to all these dwarf_expr_context variants,
accepting a dwarf2_per_objfile parameter.  This dwarf2_per_objfile
generally comes from a symbol baton created earlier.

For frame-related expressions, the dwarf2_per_objfile object must be
passed through the dwarf2_frame_cache object.  This lead to the
dwarf2_frame_find_fde function returning (by parameter) a
dwarf2_per_objfile object.  I then realized that this made the existing
"out_offset" parameter redundant.  This offset is
`objfile->text_section_offset ()`, so it can be recomputed from the
dwarf2_per_objfile object at any time.  I therefore opted to remove this
output parameter, as well as the offset field of dwarf2_frame_cache.

*Note*, there's one spot I'm particularly unsure about.  In
dwarf_evaluate_loc_desc::push_dwarf_reg_entry_value, we would save and
overwrite the offset value in the context, along with a bunch of other
state.  This is because we might be about to evaluate something in a
different CU that the current one.  If the two CUs are in the same
objfile, then the text_offset is the same, as it's a property of the
objfile.  However, if the two CUs are possibly in different objfiles,
then it means the text_offsets are different.  It would also mean we
would need to save and restore the dwarf2_per_objfile in the context.
Is that even possible?

gdb/ChangeLog:

	* dwarf2/expr.h (struct dwarf_expr_context)
	<dwarf_expr_context>: Add dwarf2_per_objfile parameter.
	<offset>: Remove.
	<per_objfile>: New member.
	* dwarf2/expr.c (dwarf_expr_context::dwarf_expr_context): Add
	dwarf2_per_objfile parameter.  Don't set offset, set
	per_objfile.
	(dwarf_expr_context::execute_stack_op): Use offset from objfile.
	* dwarf2/frame.c (dwarf2_frame_find_fde): Return (by parameter)
	a dwarf2_per_objfile object instead of an offset.
	(class dwarf_expr_executor) <dwarf_expr_executor>: Add
	constructor.
	(execute_stack_op): Add dwarf2_per_objfile parameter, pass it
	to dwarf2_expr_executor constructor.  Don't set offset.
	(dwarf2_fetch_cfa_info): Update.
	(struct dwarf2_frame_cache) <text_offset>: Remove.
	<per_objfile>: New field.
	(dwarf2_frame_cache): Update.
	(dwarf2_frame_prev_register): Update.
	* dwarf2/loc.c (class dwarf_evaluate_loc_desc)
	<dwarf_evaluate_loc_desc>: Add constructor.
	(dwarf2_evaluate_loc_desc_full): Update.
	(dwarf2_locexpr_baton_eval): Update.
	(class symbol_needs_eval_context) <symbol_needs_eval_context>:
	Add constructor.
	(dwarf2_loc_desc_get_symbol_read_needs): Update.

Change-Id: I14df060669cc36ad04759f1708c6d7b1fda77727
2020-05-27 11:15:56 -04:00
Simon Marchi
293e7e5114 Move int type methods out of dwarf2_per_cu_data
These methods rely on the current objfile to create types based on it.
Since dwarf2_per_cu_data is to become objfile-independent, these methods
need to mvoe.

int_type can be in dwarf2_per_objfile, as it only requires knowing about
the objfile.

addr_sized_int_type and addr_type also need to know about the DWARF
address type size, which is CU-specific.  The dwarf2_cu objects seems
like a good place for it, as it knows both about the current objfile and
the current CU.

gdb/ChangeLog:

	* dwarf2/read.h (struct dwarf2_per_cu_data) <addr_type,
	addr_sized_int_type>: Move to dwarf2_cu.
	<int_type>: Move to dwarf2_per_objfile.
	(struct dwarf2_per_objfile) <int_type>: Move here.
	* dwarf2/read.c (struct dwarf2_cu) <addr_type,
	addr_sized_int_type>: Move here.
	(read_func_scope): Update.
	(read_array_type): Update.
	(read_tag_string_type): Update.
	(attr_to_dynamic_prop): Update.
	(dwarf2_per_cu_data::int_type): Rename to...
	(dwarf2_per_objfile::int_type): ... this.
	(dwarf2_per_cu_data::addr_sized_int_type): Rename to...
	(dwarf2_cu::addr_sized_int_type): ... this.
	(read_subrange_type): Update.
	(dwarf2_per_cu_data::addr_type): Rename to...
	(dwarf2_cu::addr_type): ... this.
	(set_die_type): Update.

Change-Id: Ic4708ef99d43a8d99325ff91dee59b2eb706cb8f
2020-05-27 11:15:56 -04:00
Simon Marchi
64874a4030 Remove reference to dwarf2_per_cu_data::dwarf2_per_objfile in queue_and_load_all_dwo_tus
In this context, we know that per_cu->cu will be set, as there is this
assertion:

    gdb_assert (per_cu->cu != NULL)

So in order to remove the dwarf2_per_cu_data::dwarf2_per_objfile
reference in queue_and_load_all_dwo_tus, we can go through per_cu->cu.
This adds a reference to dwarf2_per_cu_data::cu, but it will get removed
eventually, in a subsequent patch.

gdb/ChangeLog:

	* dwarf2/read.c (queue_and_load_all_dwo_tus): Access per_objfile
	data through per_cu->cu.

Change-Id: Id4662828ac3c5bc93fe221df3c9bd9a36a8427ad
2020-05-27 11:15:56 -04:00
Simon Marchi
4ab09049d6 Pass dwarf2_cu objects to dwo-related functions, instead of dwarf2_per_cu_data
This allows removing references to the
dwarf2_per_cu_data::dwarf2_per_objfile field.

I am not too sure of the code flow here, but ultimately
open_and_init_dwo_file calls create_cus_hash_table, and passes it
per_cu->cu.  create_cus_hash_table requires a dwarf2_cu to pass to
cutu_reader, as the "parent_cu".

The dwarf2_per_cu_data::cu link is only set when in a certain context.
It's not easy to convince myself in which situations it's safe to use
it.  Instead, if a function is going to use a dwarf2_cu, I think it's
simpler if it takes that object directly.  If it needs access to the
corresponding dwarf2_per_cu_data object, then it can used the
dwarf2_cu::per_cu field, which we know is always set.

This patch adds some references to dwarf2_per_cu_data::cu in the
cutu_reader context.  In this context, we know this field will be set,
as it's cutu_reader that is responsible for instantiating the dwarf2_cu
and assigning the field.

gdb/ChangeLog:

	* dwarf2/read.c (lookup_dwo_comp_unit): Change
	dwarf2_per_cu_data parameter fo dwarf2_cu.
	(lookup_dwo_type_unit): Likewise.
	(read_cutu_die_from_dwo): Likewise.
	(lookup_dwo_unit): Likewise.
	(open_and_init_dwo_file): Likewise.
	(lookup_dwo_cutu): Likewise.
	(lookup_dwo_comp_unit): Likewise.
	(lookup_dwo_type_unit): Likewise.
	(cutu_reader::init_tu_and_read_dwo_dies): Update.
	(cutu_reader::cutu_reader): Update.

Change-Id: I0406a715b0797963bde2bd86237f159cbece5839
2020-05-27 11:15:56 -04:00
Simon Marchi
47b14e8676 Add dwarf2_per_objfile parameter to process_full_{comp,type}_unit
This allows removing the dwarf2_per_cu_data::dwarf2_per_objfile
references in them.

gdb/ChangeLog:

	* dwarf2/read.c (process_full_comp_unit): Add dwarf2_per_objfile
	parameter.
	(process_full_type_unit): Likewise.
	(process_queue): Update.

Change-Id: Ie68baa8cc4bf1f81cc67d4ad13a59881b4c3feb6
2020-05-27 11:15:56 -04:00
Simon Marchi
43182c09c6 Add dwarf2_per_objfile parameter to recursively_compute_inclusions
This allows removing dwarf2_per_cu_data::dwarf2_per_objfile references
in recursively_compute_inclusions and compute_compunit_symtab_includes.

gdb/ChangeLog:

	* dwarf2/read.c (recursively_compute_inclusions): Add
	dwarf2_per_objfile parameter.
	(compute_compunit_symtab_includes): Likewise.
	(process_cu_includes): Update.

Change-Id: I1ee7f8dfc07b39763985e6764e8ce04dcc943ec5
2020-05-27 11:15:55 -04:00
Simon Marchi
7aa104c423 Add dwarf2_per_objfile parameter to create_partial_symtab
This allows removing a dwarf2_per_cu_data::dwarf2_per_objfile reference.

gdb/ChangeLog:

	* dwarf2/read.c (create_partial_symtab): Add dwarf2_per_objfile
	parameter.
	(create_type_unit_group): Update.
	(process_psymtab_comp_unit_reader): Update.
	(build_type_psymtabs_reader): Update.

Change-Id: I72e3a8fce8022943ce6992fb623e05636cd0e3a5
2020-05-27 11:15:55 -04:00
Simon Marchi
e3beb21d35 Remove dwarf2_per_cu_data::dwarf2_per_objfile reference in cutu_reader::keep
Here, it should be safe to use dwarf2_per_cu_data->cu->per_objfile, as
we know that dwarf2_per_cu_data->cu will be set at this point.

Note that this adds a reference to dwarf2_per_cu_data::cu, which we'll
want to remove later, but the current focus is to remove references to
dwarf2_per_cu_data::dwarf2_per_objfile.  We'll deal with that in a
subsequent patch.

gdb/ChangeLog:

	* dwarf2/read.c (cutu_reader::keep): Access dwarf2_per_objfile
	object through m_this_cu->cu.

Change-Id: I8dc26d4db021e0b9e9306eb033965b2704bba87c
2020-05-27 11:15:55 -04:00
Simon Marchi
d460f6600a Make queue_and_load_dwo_tu receive a dwarf2_cu
queue_and_load_dwo_tu, used as a callback for htab_traverse_noresize,
currently receives a dwarf2_per_cu_data as its `info` user data.  It
accesses the current dwarf2_cu object through the dwarf2_per_cu_data::cu field.
This field will be removed, because the dwarf2_per_cu_data will become
objfile-independent, while dwarf_cu will remain objfile-dependent.

To remove references to this field, change queue_and_load_dwo_tu so
that it expects to receive a pointer to the dwarf2_cu as its info
parameter.

A reference to dwarf2_per_cu_data::cu needs to be added, but it will get
removed in a subsequent patch, when this function gets re-worked.

I kept this as a separate patch, because since there's no strong typing
here, it's easy to miss something.

gdb/ChangeLog:

	* dwarf2/read.c (queue_and_load_dwo_tu): Expect a dwarf2_cu as
	the info parameter.
	(queue_and_load_all_dwo_tus): Pass per_cu->cu.

Change-Id: I3db2a780f0e2157d52ce6939f478558ffe20abcf
2020-05-27 11:15:55 -04:00
Simon Marchi
ab43249077 Add dwarf2_per_objfile parameter to cutu_reader's constructors
The cutu_reader type is used for reading the CU represented by the
passed dwarf2_per_cu_data object.  This reading is done in the context
of a given obfile, which is currently the one associated to the passed
dwarf2_per_cu_data object.  Since the dwarf2_per_cu_data type will
become objfile-independent, we will need to pass the objfile separately.

This patch therefore adds a dwarf2_per_objfile parameter to the
cutu_reader constructors, as well as to their callers, up until the
point where we can get the dwarf2_per_objfile object from somewhere
else.  In the end, this allows removing the reference to
dwarf2_per_cu_data::dwarf2_per_objfile in cutu_reader::cutu_reader.

A few dwarf2_per_cu_data::dwarf2_per_objfile references are added (e.g.
in dwarf2_fetch_die_type_sect_off).  This is temporary, this will be
removed once these functions will get re-worked in subsequent patches.

gdb/ChangeLog:

	* dwarf2/read.c (class cutu_reader) <cutu_reader>: Add
	per_objfile parameter.
	(load_full_type_unit): Add per_objfile parameter.
	(read_signatured_type): Likewise.
	(load_full_comp_unit): Likewise.
	(load_cu): Likewise.
	(dw2_do_instantiate_symtab): Likewise.
	(dw2_get_file_names): Likewise.
	(dw2_map_symtabs_matching_filename): Update.
	(dw_expand_symtabs_matching_file_matcher): Update.
	(dw2_map_symbol_filenames): Update.
	(process_psymtab_comp_unit): Add per_objfile parameter.
	(build_type_psymtabs_1): Update.
	(process_skeletonless_type_unit): Update.
	(dwarf2_build_psymtabs_hard): Update.
	(load_partial_comp_unit): Add per_objfile parameter.
	(scan_partial_symbols): Update.
	(load_full_comp_unit): Add per_objfile parameter.
	(process_imported_unit_die): Update.
	(create_cus_hash_table): Update.
	(find_partial_die): Update.
	(dwarf2_read_addr_index): Update.
	(follow_die_offset): Update.
	(dwarf2_fetch_die_loc_sect_off): Update.
	(dwarf2_fetch_constant_bytes): Update.
	(dwarf2_fetch_die_type_sect_off): Update.
	(follow_die_sig_1): Update.
	(load_full_type_unit): Add per_objfile parameter.
	(read_signatured_type): Likewise.

Change-Id: Ibd7bbc443df8b9b8b6f96ff18e93a60ee721b85f
2020-05-27 11:15:55 -04:00
Simon Marchi
313bad1bc6 Use bfd_get_filename instead of objfile_name in lookup_dwo_unit
There should be no functional difference, as objfile_name defers to
bfd_get_filename if objfile::obfd is non-NULL, which should be the case
here.  This allows to remove a reference to
dwarf2_per_cu_data::dwarf2_per_objfile.

gdb/ChangeLog:

	* dwarf2/read.c (lookup_dwo_unit): Use bfd_get_filename instead
	of objfile_name.

Change-Id: I1e1c1870820aec23701edc9c3994612da5781c23
2020-05-27 11:15:55 -04:00
Simon Marchi
c3699833af Make dwarf2_get_dwz_file take a dwarf2_per_bfd
This allows removing a per_bfd->dwarf2_per_objfile reference in
get_abbrev_section_for_cu.

This requires saving the bfd in dwarf2_per_bfd.  The constructor of
dwarf2_per_bfd already accepts the bfd, so it's just a matter of saving
it in a field.

I replaced uses of objfile_name with bfd_get_filename, which should be
equivalent in this case.

gdb/ChangeLog:

	* dwarf2/read.h (struct dwarf2_per_bfd) <obfd>: New member.
	(dwarf2_get_dwz_file): Replace parameter with dwarf2_per_bfd.
	* dwarf2/read.c (dwarf2_per_bfd::dwarf2_per_bfd): Assign obfd
	field.
	(dwarf2_get_dwz_file): Replace parameter with dwarf2_per_bfd.
	(create_cus_from_index): Update.
	(dwarf2_read_gdb_index): Update.
	(create_cus_from_debug_names): Update.
	(dwarf2_read_debug_names): Update.
	(get_abbrev_section_for_cu): Update.
	(create_all_comp_units): Update.
	(read_attribute_value): Update.
	(get_debug_line_section): Update.
	* dwarf2/index-cache.c (index_cache::store): Update.
	* dwarf2/index-write.c (save_gdb_index_command): Update.
	* dwarf2/macro.c (dwarf_decode_macro_bytes): Update.

Change-Id: Ifb23f55dda93c499aae57b6a9aff9c6ff9d2f45f
2020-05-27 11:15:54 -04:00
Simon Marchi
1859c670e9 Add dwarf2_per_bfd field to dwarf2_per_cu_data
Some code using dwarf2_per_cu_data objects accesses the corresponding
dwarf2_per_bfd using the following pattern:

    per_cu->dwarf2_per_objfile->per_bfd

Since dwarf2_per_cu_data objects are going to become
objfile-independent, the dwarf2_per_objfile link must go.  To replace
it, add a dwarf2_per_cu_data->per_bfd link.  It makes sense to have it
there because the dwarf2_per_cu_data objects belong to the
dwarf2_per_bfd, so this is essentially just a backlink to their owner.

gdb/ChangeLog:

	* dwarf2/read.h (struct dwarf2_per_cu_data) <per_bfd>: New
	member.
	* dwarf2/read.c (dwarf2_per_bfd::allocate_per_cu): Initialize
	dwarf2_per_cu_data::per_bfd.
	(dwarf2_per_bfd::allocate_signatured_type): Likewise.
	(create_type_unit_group): Likewise.
	(queue_comp_unit): Remove reference to
	per_cu->dwarf2_per_objfile.
	(maybe_queue_comp_unit): Likewise.
	(fill_in_sig_entry_from_dwo_entry): Assign new field.
	(create_cus_hash_table): Assign new field.

Change-Id: I4ba0a393e64a14489ef061261a3dede1509d055b
2020-05-27 11:15:54 -04:00
Simon Marchi
5e22e966a0 Remove dwarf2_cu->per_cu->dwarf2_per_objfile references
Change spots that access the dwarf2_per_objfile object through this
pattern:

  dwarf2_cu->per_cu->dwarf2_per_objfile

to

  dwarf2_cu->per_objfile

This allows removing many references to
dwarf2_per_cu_data::dwarf2_per_objfile.

Again, I hope the following ChangeLog entry will be fine.  I'd rather not
list all the affected functions, as it would be time-consuming and a bit
pointless.

gdb/ChangeLog:

	* dwarf2/read.c: Replace
	dwarf2_cu->per_cu->dwarf2_per_objfile references with
	dwarf2_cu->per_objfile throughout.

Change-Id: I00f44e88295f70ae805a4b18e8144ca92154612e
2020-05-27 11:15:54 -04:00
Simon Marchi
97a1449a95 Remove reference to dwarf2_per_cu_data::dwarf2_per_objfile in dw2_do_instantiate_symtab
This patch begins by removing the per_cu->dwarf2_per_objfile reference
in dw2_do_instantiate_symtab, instead accepting a dwarf2_per_objfile
object as a parameter.  It then fixes the fallouts.  In this context,
the dwarf2_per_objfile is generally derived from an objfile passed to a
quick_symbol_functions callback.

gdb/ChangeLog:

	* dwarf2/read.c (dw2_do_instantiate_symtab): Add per_objfile
	parameter, don't use per_cu->dwarf2_per_objfile.
	(dw2_instantiate_symtab): Likewise.
	(dw2_find_last_source_symtab): Update.
	(dw2_map_expand_apply): Update.
	(dw2_lookup_symbol): Update.
	(dw2_expand_symtabs_for_function): Update.
	(dw2_expand_all_symtabs): Update.
	(dw2_expand_symtabs_with_fullname): Update.
	(dw2_expand_symtabs_matching_one): Add per_objfile parameter,
	don't use per_cu->dwarf2_per_objfile.
	(dw2_expand_marked_cus): Update.
	(dw2_find_pc_sect_compunit_symtab): Update.
	(dw2_debug_names_lookup_symbol): Update.
	(dw2_debug_names_expand_symtabs_for_function): Update.
	(dw2_debug_names_map_matching_symbols): Update.
	(dwarf2_psymtab::expand_psymtab): Update.

Change-Id: I248300822a09bae8470b65a7122d04fb9cb2b5bc
2020-05-27 11:15:54 -04:00
Simon Marchi
9e021579fa Add dwarf2_per_objfile field to dwarf2_cu
Subsequent patches will make dwarf2_per_cu_data objfile-independent.
This means that the dwarf2_per_cu_data::dwarf2_per_objfile field must
go.

The code using a dwarf2_cu structure currently accesses the current
dwarf2_per_objfile object through dwarf2_cu->per_cu->dwarf2_per_objfile.
Since it's ok for the dwarf2_cu to know about the current objfile (a
dwarf2_cu is always used in the context of a particular objfile), add a
dwarf2_per_objfile field to dwarf2_cu.  Upcoming patches will gradually
remove uses of dwarf2_per_cu_data::dwarf2_per_objfile in favor of
dwarf2_cu::dwarf2_per_objfile, until the former can be removed.

gdb/ChangeLog:

	* dwarf2/read.c (struct dwarf2_cu) <dwarf2_cu>: Add parameter.
	<per_objfile>: New member.
	(class cutu_reader) <init_tu_and_read_dwo_dies>: Add parameter.
	(cutu_reader::init_tu_and_read_dwo_dies): Add parameter, update
	call to dwarf2_cu.
	(cutu_reader::cutu_reader): Update.
	(dwarf2_cu::dwarf2_cu): Add parameter, initialize per_objfile.

Change-Id: I8fd0da7371f65baea1ea7787aad08e10453bc565
2020-05-27 11:15:54 -04:00
Simon Marchi
ae090bdbf8 Move die_type_hash to dwarf2_per_objfile
The die_type_hash field can't be shared between multiple obfiles, as it
holds `struct type` objects, which are objfile-specific.  Move it from
dwarf2_per_bfd to dwarf2_per_objfile and update all references.

gdb/ChangeLog:

	* dwarf2/read.h (struct dwarf2_per_bfd) <die_type_hash>: Move to
	struct dwarf2_per_objfile.
	(struct dwarf2_per_objfile) <die_type_hash>: Move from struct
	dwarf2_per_bfd.
	* dwarf2/read.c (set_die_type): Update.
	(get_die_type_at_offset): Update.

Change-Id: I3589777ed3579bcabafd2ba859d27babe4502bfb
2020-05-27 11:15:54 -04:00
Simon Marchi
af758d117e Remove symtab links from dwarf2_psymtab and dwarf2_per_cu_quick_data
The dwarf2_psymtab and dwarf2_per_cu_quick_data types contain a pointer
to a compunit_symtab, which is a pointer to the corresponding full
symtab.  The dwarf2_psymtab and dwarf2_per_cu_quick_data objects are
going to become objfile-independent, and possibly shared by multiple
objfiles, whereas compunit_symtab will stay objfile-dependent.  This
backlink to the compunit_symtab must therefore be removed.

This patch replaces them with a vector in the dwarf2_per_objfile type,
that serves as a mapping from dwarf2_per_cu_data objects to
compunit_symtab objects, for this particular objfile.  The vector is
indexed using the index assigned to the dwarf2_per_cu_data at its
creation.

I removed the get_compunit_symtab, as it appears to bring not much value
over calling dwarf2_per_objfile::get_symtab directly.

gdb/ChangeLog:

YYYY-MM-DD  Tom Tromey  <tom@tromey.com>
YYYY-MM-DD  Simon Marchi  <simon.marchi@efficios.com>

	* dwarf2/read.h (struct dwarf2_per_bfd) <num_psymtabs>: New
	method.
	(struct dwarf2_per_objfile) <resize_symtabs, symtab_set_p,
	get_symtab, set_symtab>: New methods.
	<m_symtabs>: New field.
	(struct dwarf2_psymtab): Derive from partial_symtab.
	<readin_p, get_compunit_symtab>: Declare methods.
	* dwarf2/read.c (dwarf2_per_objfile::symtab_set_p,
	dwarf2_per_objfile::get_symtab, dwarf2_per_objfile::set_symtab):
	New methods.
	(struct dwarf2_per_cu_quick_data) <compunit_symtab>: Remove.
	(dw2_do_instantiate_symtab, dw2_instantiate_symtab)
	(dw2_map_expand_apply, dw2_map_symtabs_matching_filename)
	(dw2_symtab_iter_next, dw2_print_stats)
	(dw2_expand_symtabs_with_fullname)
	(dw2_expand_symtabs_matching_one)
	(dw_expand_symtabs_matching_file_matcher)
	(dw2_find_pc_sect_compunit_symtab, dw2_map_symbol_filenames)
	(dw2_debug_names_iterator::next)
	(dw2_debug_names_map_matching_symbols)
	(fill_in_sig_entry_from_dwo_entry, dwarf2_psymtab::read_symtab)
	(process_queue, dwarf2_psymtab::expand_psymtab): Update.
	(dwarf2_psymtab::readin_p, dwarf2_psymtab::get_compunit_symtab):
	New methods.
	(get_compunit_symtab, process_full_comp_unit)
	(process_full_type_unit): Update.
	(dwarf2_build_psymtabs, dwarf2_initialize_objfile, add_type_unit): Call

Change-Id: Iec53d96e0b70a57d8b68408febdac3c6c3d4854b
2020-05-27 11:15:47 -04:00
Simon Marchi
5989a64ed5 Split dwarf2_per_objfile into dwarf2_per_objfile and dwarf2_per_bfd
This is the first step of splitting dwarf2_per_objfile in two, one
structure for objfile-independent data (dwarf2_per_bfd) and one for
objfile-dependent data (dwarf2_per_objfile).

The existing dwarf2_per_objfile is renamed dwarf2_per_bfd, and a new
dwarf2_per_objfile type is introduced, which sits "in between" the
objfile and dwarf2_per_bfd.

So where we had this before:

  objfile -> dwarf2_per_objfile (*)

we now have this:

  objfile -> dwarf2_per_objfile -> dwarf2_per_bfd (*)

(*) Note that the dwarf2_per_objfile in the former corresponds to
the dwarf2_per_bfd in the latter.

I've done the minimal amount of changes in this patch: following patches
will incrementally move things that are not actually shareable between
objfiles from dwarf2_per_bfd to dwarf2_per_objfile.

Most references to dwarf2_per_objfile objects are changed to
dwarf2_per_objfile->per_bfd.  To avoid many of these replacements, which
would have to be reverted later anyway, I've moved right away the
objfile backlink to the new dwarf2_per_objfile structure in this patch.
I've also moved the read_line_string method, since it references the
objfile backlink, and it's actually not difficult to move.

Once the moves are completed, multiple dwarf2_per_objfile sharing the
same BFD will point to the same single instance of dwarf2_per_bfd (as
long as they don't require relocation).

dwarf2_has_info, where we create these objects, is updated to the new
architecture.

I've had to change the get_gdb_index_contents_ftype typedef and related
functions.  The parameter type was changed from dwarf2_per_objfile to
dwarf2_per_bfd, otherwise the template wouldn't work.

Please excuse the terse ChangeLog entry, I have not listed all the
functions where dwarf2_per_objfile has been changed to
dwarf2_per_objfile->per_bfd.  It would take a considerable amount of
time and would not really be useful in the end.

gdb/ChangeLog:

	* dwarf2/read.h (dwarf2_per_objfile): Rename to dwarf2_per_bfd,
	then introduce a new dwarf2_per_objfile type.
	<read_line_string>: Move to the new dwarf2_per_objfile type.
	<objfile>: Likewise.
	(dwarf2_per_bfd): Rename dwarf2_per_objfile to this.
	* dwarf2/read.c: Replace references to dwarf2_per_objfile with
	dwarf2_per_objfile->per_bfd.
	(dwarf2_per_objfile::dwarf2_per_objfile): Rename to...
	(dwarf2_per_bfd::dwarf2_per_bfd): ... this.
	(dwarf2_per_objfile::free_cached_comp_units): Rename to...
	(dwarf2_per_bfd::free_cached_comp_units): ... this.
	(dwarf2_has_info): Allocate dwarf2_per_bfd.
	(dwarf2_per_objfile::locate_sections): Rename to...
	(dwarf2_per_bfd::locate_sections): ... this.
	(dwarf2_per_objfile::get_cutu): Rename to...
	(dwarf2_per_bfd::get_cutu): ... this.
	(dwarf2_per_objfile::get_cu): Rename to...
	(dwarf2_per_bfd::get_cu): ... this.
	(dwarf2_per_objfile::get_tu): Rename to...
	(dwarf2_per_bfd::get_tu): ... this.
	(dwarf2_per_objfile::allocate_per_cu): Rename to...
	(dwarf2_per_bfd::allocate_per_cu): ... this.
	(dwarf2_per_objfile::allocate_signatured_type): Rename to...
	(dwarf2_per_bfd::allocate_signatured_type): ... this.
	(get_gdb_index_contents_ftype): Change parameter from
	dwarf2_per_objfile to dwarf2_per_bfd.
	* dwarf2/macro.c, dwarf2/index-write.c: Replace references to
	dwarf2_per_objfile with dwarf2_per_objfile->per_bfd.

Change-Id: I7de7b5d1ce7494aa73bfcf15f719d3c5c46e138c
2020-05-27 11:13:50 -04:00
Tom Tromey
a50264baf5 Add dwarf2_per_objfile member to DWARF batons
Various DWARF callbacks expect to be able to fetch the objfile and / or
dwarf2_per_objfile from the DWARF CU object.  However, this won't be
possible once sharing is implemented.

Because these objects are related to full symbols (e.g., they are used
to implement location expressions), they can simply store the
dwarf2_per_objfile they need.

This patch adds a per_objfile member to the various "baton" structures
and arranges to set this value when constructing the baton.

gdb/ChangeLog:

YYYY-MM-DD  Tom Tromey  <tom@tromey.com>
YYYY-MM-DD  Simon Marchi  <simon.marchi@efficios.com>

	* dwarf2/loc.c (struct piece_closure) <per_objfile>: New member.
	(allocate_piece_closure): Set "per_objfile" member.
	(dwarf2_find_location_expression, dwarf2_locexpr_baton_eval)
	(locexpr_describe_location, loclist_describe_location): Use new
	member.
	* dwarf2/read.c (read_call_site_scope)
	(mark_common_block_symbol_computed, attr_to_dynamic_prop)
	(dwarf2_const_value_attr, dwarf2_fetch_die_loc_sect_off)
	(fill_in_loclist_baton, dwarf2_symbol_mark_computed,
	handle_data_member_location): Set per_objfile member.
	* dwarf2/loc.h (struct dwarf2_locexpr_baton) <per_objfile>: New
	member.
	(struct dwarf2_loclist_baton) <per_objfile>: New member.

Change-Id: If3aaa6a0f544be86710157c3adb68fde24d80037
2020-05-27 11:13:50 -04:00
Tom Tromey
d3473f0c4b Add dwarf2_per_cu_data::index
Currently, a dwarf2_per_cu_data can hold a link to the corresponding
expanded compunit_symtab.  However, the dwarf2_per_cu_data objects are
shared across objfiles, a simple pointer won't work: each objfile
sharing the dwarf2_per_cu_data instance will have a corresponding
compunit_symtab.

Instead, this link will be stored in the dwarf2_per_objfile object
(which will contain the objfile-specific data).  To enable this, we add
an index to each dwarf2_per_cu_data and signatured_type.  The data
structure in the dwarf2_per_objfile will use this new index to map a
dwarf2_per_cu_data to its corresponding compunit_symtab, for this
objfile.

gdb/ChangeLog:

	* dwarf2/read.h (struct dwarf2_per_objfile) <allocate_per_cu,
	allocate_signatured_type>: Declare new methods.
	<m_num_psymtabs>: New member.
	(struct dwarf2_per_cu_data) <index>: New member.
	* dwarf2/read.c (dwarf2_per_objfile::allocate_per_cu)
	(dwarf2_per_objfile::allocate_signatured_type): New methods.
	(create_cu_from_index_list): Use allocate_per_cu.
	(create_signatured_type_table_from_index)
	(create_signatured_type_table_from_debug_names)
	(create_debug_type_hash_table, add_type_unit)
	(read_comp_units_from_section): Use allocate_signatured_type.

Change-Id: I7733479a38ce82a5015cb184c8acce5f8bbf2e69
2020-05-27 11:13:49 -04:00
Tom Tromey
5717c425a6 Add "objfile" parameter to two partial_symtab methods
This series will cause partial symtabs to be shared across objfiles.
However, full symtabs and symbols will still be objfile-dependent, so
will be expanded separately for each objfile.  So, a debug info reader
will need to know which objfile to consult when expanding a partial
symtab.

This patch adds an objfile parameter to the two relevant methods of
partial_symtab.  Current implementations simply ignore them.

gdb/ChangeLog:

	* psymtab.c (partial_map_expand_apply)
	(psym_find_pc_sect_compunit_symtab, psym_lookup_symbol)
	(psym_lookup_global_symbol_language)
	(psymtab_to_symtab, psym_find_last_source_symtab, dump_psymtab)
	(psym_print_stats, psym_expand_symtabs_for_function)
	(psym_map_symbol_filenames, psym_map_matching_symbols)
	(psym_expand_symtabs_matching)
	(partial_symtab::read_dependencies, maintenance_info_psymtabs)
	(maintenance_check_psymtabs): Update.
	* psympriv.h (struct partial_symtab) <readin_p,
	get_compunit_symtab>: Add objfile parameter.
	(struct standard_psymtab) <readin_p, get_compunit_symtab>:
	Likewise.
	* dwarf2/read.c (struct dwarf2_include_psymtab) <readin_p,
	get_compunit_symtab>: Likewise.
	(dwarf2_psymtab::expand_psymtab): Pass objfile argument.

Change-Id: I3f0b26787c3e78f7fb78b9fc011d91fb8690f3a0
2020-05-27 11:13:48 -04:00
Tom Tromey
4594094926 Introduce dwarf2_per_objfile::obstack
Currently much of the DWARF-related data is stored on the objfile
obstack.  This prevents sharing this data across objfiles, so this patch
adds a new obstack to dwarf2_per_objfile.  Note that the
dwarf2_per_objfile type is going to become "dwarf2_per_bfd" in a
subsequent patch, which is indeed going to be shared between objfiles.

One way to check whether this is correct is to look at the remaining
uses of objfile_obstack in the DWARF code and note that they all
appear in the "full CU" code paths.

The converse -- storing per-objfile data on the shared obstack -- is
not good, but it is just a memory leak, not a potential
use-after-free.  Double-checking this would also be useful, though.

gdb/ChangeLog:

	* dwarf2/read.h (struct dwarf2_per_objfile) <obstack>: New
	member.
	* dwarf2/read.c (delete_file_name_entry): Fix comment.
	(create_cu_from_index_list)
	(create_signatured_type_table_from_index)
	(create_signatured_type_table_from_debug_names)
	(dw2_get_file_names_reader, dwarf2_initialize_objfile)
	(dwarf2_create_include_psymtab)
	(create_debug_type_hash_table, add_type_unit)
	(create_type_unit_group, read_comp_units_from_section)
	(dwarf2_compute_name, create_cus_hash_table)
	(create_dwp_hash_table, create_dwo_unit_in_dwp_v1)
	(create_dwo_unit_in_dwp_v2, open_and_init_dwp_file): Use new
	obstack.
	(dw2_get_real_path): Likewise.  Change argument to
	dwarf2_per_objfile.

Change-Id: Icdec7be7c4d9f33d1dce4f807284f3077f7d3f03
2020-05-27 11:13:48 -04:00
Simon Marchi
ceacbf6edf gdb: remove TYPE_FIELD macro
Replace all uses of it by type::field.

Note that since type::field returns a reference to the field, some spots
are used to assign the whole field structure.  See ctfread.c, function
attach_fields_to_type, for example.  This is the same as was happening
with the macro, so I don't think it's a problem, but if anybody sees a
really nicer way to do this, now could be a good time to implement it.

gdb/ChangeLog:

	* gdbtypes.h (TYPE_FIELD): Remove.  Replace all uses with
	type::field.
2020-05-23 17:39:54 -04:00
Simon Marchi
80fc5e77f0 gdb: remove TYPE_FIELDS macro
Remove all uses of the `TYPE_FIELDS` macro.  Replace them with either:

1) type::fields, to obtain a pointer to the fields array (same as
   TYPE_FIELDS yields)
2) type::field, a new convenience method that obtains a reference to one
   of the type's field by index.  It is meant to replace

     TYPE_FIELDS (type)[idx]

   with

     type->field (idx)

gdb/ChangeLog:

	* gdbtypes.h (struct type) <field>: New method.
	(TYPE_FIELDS): Remove, replace all uses with either type::fields
	or type::field.

Change-Id: I49fba10114417deb502060c6156aa5f7fc62462f
2020-05-22 16:55:17 -04:00
Simon Marchi
3cabb6b069 gdb: add type::fields / type::set_fields
Add the `fields` and `set_fields` methods on `struct type`, in order to
remove the `TYPE_FIELDS` macro.  In this patch, the `TYPE_FIELDS` macro
is changed to the `type::fields`, so all the call sites that use it to
set the fields array are changed to use `type::set_fields`.  The next
patch will remove `TYPE_FIELDS` entirely.

gdb/ChangeLog:

	* gdbtypes.h (struct type) <fields, set_fields>: New methods.
	(TYPE_FIELDS): Use type::fields.  Change all call sites that
	modify the propery to use type::set_fields instead.

Change-Id: I05174ce68f2ce3fccdf5d8b469ff141f14886b33
2020-05-22 16:55:16 -04:00
Simon Marchi
1f704f761b gdb: remove TYPE_NFIELDS macro
Remove `TYPE_NFIELDS`, changing all the call sites to use
`type::num_fields` directly.  This is quite a big diff, but this was
mostly done using sed and coccinelle.  A few call sites were done by
hand.

gdb/ChangeLog:

	* gdbtypes.h (TYPE_NFIELDS): Remove.  Change all cal sites to use
	type::num_fields instead.

Change-Id: Ib73be4c36f9e770e0f729bac3b5257d7cb2f9591
2020-05-22 16:55:15 -04:00
Simon Marchi
5e33d5f4e1 gdb: add type::num_fields / type::set_num_fields
Add the `num_fields` and `set_num_fields` methods on `struct type`, in
order to remove the `TYPE_NFIELDS` macro.  In this patch, the
`TYPE_NFIELDS` macro is changed to use `type::num_fields`, so all the
call sites that are used to set the number of fields are changed to use
`type::set_num_fields`.  The next patch will remove `TYPE_NFIELDS`
completely.

I think that in the future, we should consider making the interface of
`struct type` better.  For example, right now it's possible for the
number of fields property and the actual number of fields set to be out
of sync.  However, I want to keep the existing behavior in this patch,
just translate from macros to methods.

gdb/ChangeLog:

	* gdbtypes.h (struct type) <num_fields, set_num_fields>: New
	methods.
	(TYPE_NFIELDS): Use type::num_fields.  Change all call sites
	that modify the number of fields to use type::set_num_fields
	instead.

Change-Id: I5ad9de5be4097feaf942d111077434bf91d13dc5
2020-05-22 16:55:14 -04:00