libabigail/tools
Dodji Seketeli dc2f054d03 Build the set of exported decls directly during DWARF loading
Until now, after the ABI corpus was built from DWARF, the translation
units of the corpus were walked and each function was considered for
addition into the set of exported decls.  During that walking, a first
version of the set was put into a std::list and then, a set of filters
(user-provided tunables like a list of regular expressions to keep or
remove some functions from the exported decls) is applied to that list
and the final set of exported decls is put in a std::vector.

Profiling has shown that this process of building the set of exported
decls is a hot spot and also that the current use of std::list was a
big memory consumer especially on binaries with large exported symbol
tables.

So this patch builds the set of exported decls "on the fly", during
DWARF reading, as opposed to waiting after the DWARF is read and
having to walk the corpus again.  The corpus defines a policy object
that encapsulates the methods for determining if a function or
variable ought to be part of the set of exported decls.  The DWARF
reader uses that policy object to determine which functions and
variables among those built during the reading ought be part of the
exported decls; the policy object also has a reference to the final
vector (managed by the corpus) that must hold the exported decls, so
the decls are put in that vector directly without unnecessary copying.

Profiling also showed that the string copying done by
{var_decl,function_decl}::get_id() was a hot spot.  So the patch
returns a reference there.

With this patch applied, the peak memory consumption of abidiff on
libabigail.so itself (abidiff libabigail.so libabigail.so) is 54MB of
resident and takes 2 minutes and 16s (on my slow system).  Without the
patch the peak consumption was more than 300MB and it was taking
slightly longer.

For the test of bug
https://sourceware.org/bugzilla/show_bug.cgi?id=17948, memory
consumtion and wall clock time spent is down from 3.4GB and 1m59s to
760MB and 0m43s.

	* include/abg-ir.h ({var,function}_decl::get_id): Return a
	reference.
	* src/abg-ir.cc ({var,function}_decl::get_id): Return a reference
	to the string rather than copying it over.
	* include/abg-corpus.h (class corpus::exported_decls_builder):
	Declare new type.
	(corpus::{sort_functions, sort_variables,
	maybe_drop_some_exported_decls, get_exported_decls_builder}):
	Declare new methods.
	* src/abg-corpus.h (corpus::exported_decls_builder::priv): Define
	new type.
	(class symtab_build_visitor_type): Remove this type that is
	useless now.
	(corpus::exported_decls_builder::{exported_decls_builder,
	exported_functions, exported_variables,
	maybe_add_fn_to_exported_fns, maybe_add_var_to_exported_vars}):
	Define new functions.
	(corpus::priv::is_public_decl_table_built): Remove this data
	member.  It's now useless.
	(corpus::priv::priv): Adjust.
	(corpus::priv::build_public_decl_table): Remove this member
	function.  It's now useless.
	(corpus::{priv::build_unreferenced_symbols_tables, get_functions,
	get_variables}): No need to build the public decls table here.
	It's already built by the time the corpus is read from DWARF now.
	(corpus::{sort_functions, sort_variables,
	maybe_drop_some_exported_decls, get_exported_decls_builder}):
	Define new member functions.
	* src/abg-dwarf-reader.cc (read_context::exported_decls_builder):
	New data member.
	(read_context::read_context): Initialize it.
	(read_context::{exported_decls_builder,
	maybe_add_fn_to_exported_fns, maybe_add_var_to_exported_vars}):
	Define new member functions.
	(read_debug_info_into_corpus): Get the the new
	'exported_decls_builder' object from the corpus and stick it into
	the read context so the DWARF reading code can use it to build the
	exported decls set.  When the DWARF reading is done, sort the set
	of exported functions and variables that was built.
	(build_ir_node_from_die): When a function or variable is built,
	consider putting it into the set of exported decls.
	* tools/abicompat.cc (main): Now that the exported decls is built
	*before* we had a chance to stick the list of symbol IDs to keep,
	call corpus::maybe_drop_some_exported_decls() to update the set of
	exported decls we should consider for the corpus.

was applied to that list and the final

Signed-off-by: Dodji Seketeli <dodji@redhat.com>
2015-02-24 13:15:10 +01:00
..
.gitignore Add .gitignore files. 2014-09-12 11:05:01 +02:00
abiar.cc Adjust archive-related code for the recent addition of tools_utils::* 2015-01-13 11:02:10 +01:00
abicompat.cc Build the set of exported decls directly during DWARF loading 2015-02-24 13:15:10 +01:00
abidiff.cc Rename diff::length() into diff::has_changes() 2015-02-05 12:44:59 +01:00
abidw.cc Expose a new libabigail::tools_utils namespace 2015-01-08 12:28:14 +01:00
abilint.cc Expose a new libabigail::tools_utils namespace 2015-01-08 12:28:14 +01:00
abisym.cc Update copyright years 2015-01-07 17:52:10 +01:00
binilint.cc Update copyright years 2015-01-07 17:52:10 +01:00
Makefile.am Do not install the abinilint program 2015-01-14 13:20:46 +01:00