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During type canonicalization there are observations that can speed-up
type comparison significantly without impacting correctness too much.
Typically, when two types are of the same name and kind, are found in
the same corpus and are defined in the same translation unit, they
ought to be the same type, even in C. So there is no need in this
case to actually perform the structural comparison of the two types
which does have a quadratic performance at best.
Using this optimization made the loading of the
drivers/gpu/drm/i915/i915.ko module go from a quasi inifite time (many
hours on my system) to less than two minutes. I am confining this
optimization to the Linux kernel case only for now, but I believe it
could benefit all C programs. I am waiting for more testing before
applying it more broadly.
Also, while looking at this, I noticed that when loading several
corpora into a given corpus group (i.e, loading several linux kernel
binaries to represent a single conceptual kernel), we sometimes fail
to recognize that a type defined in a header file that is included in
several corpora is actually the same type, and should be re-used,
rather than being re-defined in each corpus. This later adds stress
(time and space) on the system as we need to canonicalize and
de-duplicate these type later on.
This is because the "per-corpus" type maps that we use to lookup a
type by name and location when we see it (so that we know it's defined
in a different corpus of our current group) should really be
per-corpus-group type maps! That is a type can be defined in the
corpus representing a .ko binary, and that type would be seen again in
another .ko binary later. Until now, we were wrongly considering that
types were to be first defined in the corpus of the vmlinux binary,
and then could be re-used later.
I have thus fixed the code so that whenever we add a type to its
scope, the relevant per-corpus type maps are updated, as well as the
per-corpus-group ones, so that we can later lookup types in those
per-corpus-group type maps to know if a type is already defined in any
corpus of the group.
* include/abg-corpus.h (corpus::origin): Add a new
LINUX_KERNEL_BINARY_ORIGIN enumerator.
(corpus::{s,g}et_group): Declare new member
functions.
(class corpus): Make the corpus_group class friend of this one.
(corpus_group::get_main_corpus): Declare new member function.
* src/abg-corpus-priv.h (corpus::priv::group): Define new data
member.
(corpus::priv::priv): Initialize the new corpus::priv::group data
member.
* src/abg-corpus.cc (corpus::{g,s}et_group): Define new member
functions.
(corpus_group::get_main_corpus): Likewise.
(corpus_group::add_corpus): Use the new corpus::set_group() here
to to make the corpus be aware of the group it belongs to.
* src/abg-dwarf-reader.cc (read_debug_info_into_corpus): Set the
current corpus origin to the corpus::LINUX_KERNEL_BINARY_ORIGIN if
we are looking at a Linux Kernel binary.
(read_context::main_corpus_from_current_group): Use the
corpus_group::get_main_corpus method.
(should_reuse_type_from_corpus_group): Return the corpus group,
rather than the main corpus.
(read_debug_info_into_corpus): Add the current corpus to the
current corpus group before the debug info reading is done. That
way, the corpus group will be accessible from the current corpus
during the construction of the internal representation.
(read_and_add_corpus_to_group_from_elf): Add the corpus to the
group only if it wasn't added to it before.
* include/abg-ir.h (operator{==,!=}): Declare new deep equality
and inequality operators for class_or_union_sptr and
union_decl_sptr.
* src/abg-ir.cc (types_defined_same_linux_kernel_corpus_public):
Define a new static function.
(type_base::get_canonical_type_for): Use the new
types_defined_same_linux_kernel_corpus_public here to speed up
type comparison.
(equals): In the overload of class_or_union, use the new
types_defined_same_linux_kernel_corpus_public as well, to speed up
type comparison.
(operator{==,!=}): Define new deep equality and inequality
operators for class_or_union_sptr and union_decl_sptr.
(maybe_update_types_lookup_map): In the overload function for
type_decl_sptr, class_decl_sptr, union_decl_sptr,
enum_type_decl_sptr, typedef_decl_sptr, qualified_type_def_sptr,
reference_type_def_sptr, array_type_def_sptr,
array_type_def::subrange_sptr, and function_type_sptr, update the
type lookup maps of the containing corpus group as well, not just
the ones of the current corpus.
* src/abg-reader.cc (build_enum_type_decl): Forgot to set the
"is-anonymous" flag. Oops, fix this.
* tests/data/test-read-dwarf/PR22122-libftdc.so.abi: Adjust.
* tests/data/test-read-dwarf/test10-pr18818-gcc.so.abi: Adjust.
* tests/data/test-read-dwarf/test12-pr18844.so.abi: Adjust.
* tests/data/test-read-dwarf/test22-pr19097-libstdc++.so.6.0.17.so.abi: Adjust.
* tests/data/test-read-dwarf/test9-pr18818-clang.so.abi: Adjust.
Signed-off-by: Dodji Seketeli <dodji@redhat.com>
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| doc | ||
| include | ||
| m4 | ||
| scripts | ||
| src | ||
| tests | ||
| tools | ||
| .clang-format | ||
| .gitignore | ||
| abigail.m4 | ||
| AUTHORS | ||
| ChangeLog | ||
| COMMIT-LOG-GUIDELINES | ||
| COMPILING | ||
| configure.ac | ||
| CONTRIBUTING | ||
| COPYING | ||
| COPYING-GPLV3 | ||
| COPYING-LGPLV2 | ||
| COPYING-LGPLV3 | ||
| default.abignore | ||
| gen-changelog.py | ||
| install-sh | ||
| libabigail.pc.in | ||
| ltmain.sh | ||
| Makefile.am | ||
| NEWS | ||
| README | ||
| release-text-template.txt | ||
| update-copyright.sh | ||
| VISIBILITY | ||
This is the Application Binary Interface Generic Analysis and Instrumentation Library. It aims at constructing, manipulating, serializing and de-serializing ABI-relevant artifacts. The set of artifacts that we are intersted is made of quantities like types, variable, fonctions and declarations of a given library or program. For a given library or program this set of quantities is called an ABI corpus. This library aims at (among other things) providing a way to compare two ABI Corpora (apparently the plural of corpus is copora, heh, that's cool), provide detailed information about their differences, and help build tools to infer interesting conclusions about these differences. You are welcome to contribute to this project after reading the files CONTRIBUTING and COMMIT-LOG-GUIDELINES files in the source tree. Communicating with the maintainers of this project -- including sending patches to be include to the source code -- happens via email at libabigail@sourceware.org.