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Tom Tromey dd787f5e65 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

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.
2020-05-12 15:24:51 -04:00
bfd [PATCH] bfd: Fix 64-bit relocation handling for a.out 2020-05-12 12:18:09 +01:00
binutils objcopy: Mention 'entry address' in description 2020-05-07 11:39:39 +01:00
config Sync config and libiberty with GCC 2020-04-29 14:25:36 -07:00
contrib
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gas Power10 VSX scalar min-max-compare quad precision operations 2020-05-11 21:08:38 +09:30
gdb Share DWARF partial symtabs 2020-05-12 15:24:51 -04:00
gdbserver Implement debugging of WOW64 processes in gdbserver 2020-04-30 18:30:20 +02:00
gdbsupport Fix typo (thead -> thread) 2020-04-28 11:38:26 +02:00
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gold PowerPC Rename powerxx to power10 2020-05-11 21:08:36 +09:30
gprof Updated French translation for the gprof sub-directory. 2020-05-07 10:48:21 +01:00
include Power10 Reduced precision outer product operations 2020-05-11 21:08:37 +09:30
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ld Regen ld/Makefile.in 2020-05-12 09:19:26 +09:30
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		   README for GNU development tools

This directory contains various GNU compilers, assemblers, linkers, 
debuggers, etc., plus their support routines, definitions, and documentation.

If you are receiving this as part of a GDB release, see the file gdb/README.
If with a binutils release, see binutils/README;  if with a libg++ release,
see libg++/README, etc.  That'll give you info about this
package -- supported targets, how to use it, how to report bugs, etc.

It is now possible to automatically configure and build a variety of
tools with one command.  To build all of the tools contained herein,
run the ``configure'' script here, e.g.:

	./configure 
	make

To install them (by default in /usr/local/bin, /usr/local/lib, etc),
then do:
	make install

(If the configure script can't determine your type of computer, give it
the name as an argument, for instance ``./configure sun4''.  You can
use the script ``config.sub'' to test whether a name is recognized; if
it is, config.sub translates it to a triplet specifying CPU, vendor,
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If you have more than one compiler on your system, it is often best to
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also set CC when running make.  For example (assuming sh/bash/ksh):

	CC=gcc ./configure
	make

A similar example using csh:

	setenv CC gcc
	./configure
	make

Much of the code and documentation enclosed is copyright by
the Free Software Foundation, Inc.  See the file COPYING or
COPYING.LIB in the various directories, for a description of the
GNU General Public License terms under which you can copy the files.

REPORTING BUGS: Again, see gdb/README, binutils/README, etc., for info
on where and how to report problems.