Go to file
David Malcolm fd111c419d analyzer: fix state explosions due to SCC bug
Debugging the state explosion of the very large switch statement in
gcc.dg/analyzer/pr96653.c showed that the worklist was failing to
order the exploded nodes correctly; the in-edges at the join point
after the switch were not getting processed together, but were instead
being rocessed in smaller batches, bloating the exploded graph until the
per-point limit was reached.

The root cause turned out to be a bug in creating the strongly-connected
components for the supergraph: the code was considering interprocedural
edges as well as intraprocedural edges, leading to unpredictable
misorderings of the SCC and worklist, leading to bloating of the
exploded graph.

This patch fixes the SCC creation so it only considers intraprocedural
edges within the supergraph.  It also tweaks worklist::key_t::cmp to
give higher precedence to call_string over differences within a
supernode, since enodes with different call_strings can't be merges.
In practise, none of my test cases were affected by this latter change,
though it seems to be the right thing to do.

With this patch, the very large switch statement in
gcc.dg/analyzer/pr96653.c is handled in a single call to
exploded_graph::maybe_process_run_of_before_supernode_enodes:
   merged 358 in-enodes into 2 out-enode(s) at SN: 402
and that testcase no longer hits the per-program-point limits.

gcc/analyzer/ChangeLog:
	* engine.cc (strongly_connected_components::strong_connect): Only
	consider intraprocedural edges when creating SCCs.
	(worklist::key_t::cmp): Add comment.  Treat call_string
	differences as more important than differences of program_point
	within a supernode.

gcc/testsuite/ChangeLog:
	PR analyzer/96653
	* gcc.dg/analyzer/loop-0-up-to-n-by-1-with-iter-obj.c: Update
	expected number of exploded nodes.
	* gcc.dg/analyzer/malloc-vs-local-1a.c: Update expected number
	of exploded nodes.
	* gcc.dg/analyzer/pr96653.c: Remove -Wno-analyzer-too-complex.
2020-09-16 19:04:16 -04:00
config Fixup config/ChangeLog. 2020-09-10 10:17:51 +02:00
contrib Daily bump. 2020-08-27 00:16:27 +00:00
fixincludes Allow CONFIG_SHELL to override build-time shell in mkheaders 2020-02-20 22:09:03 -03:00
gcc analyzer: fix state explosions due to SCC bug 2020-09-16 19:04:16 -04:00
gnattools
gotools
include Daily bump. 2020-09-16 00:16:37 +00:00
INSTALL
intl intl: Unbreak intl build with bison 3 when no regeneration is needed [PR92008] 2020-04-16 11:55:00 +02:00
libada
libatomic Daily bump. 2020-09-12 00:16:30 +00:00
libbacktrace libbacktrace, Mach-O : Support PowerPC archs. 2020-09-16 19:37:28 +01:00
libcc1 Daily bump. 2020-09-11 00:16:28 +00:00
libcpp Daily bump. 2020-09-08 00:16:32 +00:00
libdecnumber Daily bump. 2020-07-31 00:16:26 +00:00
libffi libffi/test: Fix compilation for build sysroot 2020-04-25 21:27:14 +01:00
libgcc C-SKY: Enable crtbegin/crtend.o of libgcc for elf target 2020-09-16 19:34:02 +08:00
libgfortran Daily bump. 2020-09-04 00:16:32 +00:00
libgo libgo: additional type/const references in sysinfo.c 2020-09-15 17:41:57 -07:00
libgomp c++: local-scope OMP UDR reductions have no template head 2020-09-16 12:16:11 -07:00
libhsail-rt
libiberty Daily bump. 2020-09-09 00:16:29 +00:00
libitm Daily bump. 2020-07-25 00:16:22 +00:00
libobjc Daily bump. 2020-05-30 00:16:27 +00:00
liboffloadmic Add missing ChangeLog entries. 2020-05-05 16:10:13 +02:00
libphobos Daily bump. 2020-09-11 00:16:28 +00:00
libquadmath Daily bump. 2020-05-30 00:16:27 +00:00
libsanitizer Daily bump. 2020-07-17 00:16:27 +00:00
libssp Daily bump. 2020-05-30 00:16:27 +00:00
libstdc++-v3 Daily bump. 2020-09-12 00:16:30 +00:00
libvtv Daily bump. 2020-05-30 00:16:27 +00:00
lto-plugin Daily bump. 2020-09-11 00:16:28 +00:00
maintainer-scripts Daily bump. 2020-05-30 00:16:27 +00:00
zlib Daily bump. 2020-05-30 00:16:27 +00:00
.dir-locals.el
.gitattributes
.gitignore Add .clang-tidy to git ignored. 2020-06-12 16:03:02 +02:00
ABOUT-NLS
ar-lib
ChangeLog Daily bump. 2020-08-27 00:16:27 +00:00
ChangeLog.jit
ChangeLog.tree-ssa
compile
config-ml.in
config.guess
config.rpath
config.sub
configure configure: Also check C++11 (flags) for ${build} compiler not only for ${host} 2020-08-20 21:59:00 +02:00
configure.ac configure: Also check C++11 (flags) for ${build} compiler not only for ${host} 2020-08-20 21:59:00 +02:00
COPYING
COPYING3
COPYING3.LIB
COPYING.LIB
COPYING.RUNTIME
depcomp
install-sh
libtool-ldflags
libtool.m4
lt~obsolete.m4
ltgcc.m4
ltmain.sh Do not use HAVE_DOS_BASED_FILE_SYSTEM for Cygwin. 2020-04-17 09:22:51 +02:00
ltoptions.m4
ltsugar.m4
ltversion.m4
MAINTAINERS MAINTAINERS: Add myself as OpenACC maintainer 2020-08-26 17:58:22 +02:00
Makefile.def Merge top-level configury changes from gdb 2020-04-09 06:52:55 -06:00
Makefile.in Merge top-level configury changes from gdb 2020-04-09 06:52:55 -06:00
Makefile.tpl
missing
mkdep
mkinstalldirs
move-if-change
multilib.am
README
symlink-tree
test-driver
ylwrap

This directory contains the GNU Compiler Collection (GCC).

The GNU Compiler Collection is free software.  See the files whose
names start with COPYING for copying permission.  The manuals, and
some of the runtime libraries, are under different terms; see the
individual source files for details.

The directory INSTALL contains copies of the installation information
as HTML and plain text.  The source of this information is
gcc/doc/install.texi.  The installation information includes details
of what is included in the GCC sources and what files GCC installs.

See the file gcc/doc/gcc.texi (together with other files that it
includes) for usage and porting information.  An online readable
version of the manual is in the files gcc/doc/gcc.info*.

See http://gcc.gnu.org/bugs/ for how to report bugs usefully.

Copyright years on GCC source files may be listed using range
notation, e.g., 1987-2012, indicating that every year in the range,
inclusive, is a copyrightable year that could otherwise be listed
individually.