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Patrick Palka 37244b217a c++: Fix constexpr evaluation of self-modifying CONSTRUCTORs [PR94219]
This PR reveals that cxx_eval_bare_aggregate and cxx_eval_store_expression do
not anticipate that a constructor element's initializer could mutate the
underlying CONSTRUCTOR.  Evaluation of the initializer could add new elements to
the underlying CONSTRUCTOR, thereby potentially invalidating any pointers to
or assumptions about the CONSTRUCTOR's elements, and so these routines should be
prepared for that.

To fix this problem, this patch makes cxx_eval_bare_aggregate and
cxx_eval_store_expression recompute the constructor_elt pointers through which
we're assigning, after it evaluates the initializer.  Care is taken to to not
slow down the common case where the initializer does not modify the underlying
CONSTRUCTOR.

gcc/cp/ChangeLog:

	PR c++/94219
	PR c++/94205
	* constexpr.c (get_or_insert_ctor_field): Split out (while adding
	support for VECTOR_TYPEs, and optimizations for the common case)
	from ...
	(cxx_eval_store_expression): ... here.  Rename local variable
	'changed_active_union_member_p' to 'activated_union_member_p'.  Record
	the sequence of indexes into 'indexes' that yields the subobject we're
	assigning to.  Record the integer offsets of the constructor indexes
	we're assigning through into 'index_pos_hints'.  After evaluating the
	initializer of the store expression, recompute 'valp' using 'indexes'
	and using 'index_pos_hints' as hints.
	(cxx_eval_bare_aggregate): Tweak comments.  Use get_or_insert_ctor_field
	to recompute the constructor_elt pointer we're assigning through after
	evaluating each initializer.

gcc/testsuite/ChangeLog:

	PR c++/94219
	PR c++/94205
	* g++.dg/cpp1y/constexpr-nsdmi3.C: New test.
	* g++.dg/cpp1y/constexpr-nsdmi4.C: New test.
	* g++.dg/cpp1y/constexpr-nsdmi5.C: New test.
	* g++.dg/cpp1z/lambda-this5.C: New test.
2020-04-04 12:14:01 -04:00
config Use a non-empty test program to test ability to link. 2020-02-12 13:22:07 -08:00
contrib Improve svn-rev to search for pattern at line beginning. 2020-04-03 12:30:39 +02:00
fixincludes Allow CONFIG_SHELL to override build-time shell in mkheaders 2020-02-20 22:09:03 -03:00
gcc c++: Fix constexpr evaluation of self-modifying CONSTRUCTORs [PR94219] 2020-04-04 12:14:01 -04:00
gnattools PR81878: fix --disable-bootstrap --enable-languages=ada 2018-11-20 00:07:47 +00:00
gotools libgo: update to Go1.14beta1 2020-01-21 23:53:22 -08:00
include Clear me from patch ownership. 2020-04-01 11:58:35 +02:00
INSTALL
intl Fixes after recent configure changes relating to static libraries 2020-02-01 00:34:28 +00:00
libada Add `--with-toolexeclibdir=' configuration option 2020-01-24 11:24:25 +00:00
libatomic libatomic: Fix last change [PR55930] 2020-02-22 19:55:09 +01:00
libbacktrace libbacktrace: update to current libgo test file 2020-02-15 18:25:13 -08:00
libcc1 c++: Fix return type deduction with an abbreviated function template 2020-02-10 20:43:53 -05:00
libcpp Update cpplib sr.po. 2020-03-31 18:09:30 +00:00
libdecnumber Update copyright years. 2020-01-01 12:51:42 +01:00
libffi Add `--with-toolexeclibdir=' configuration option 2020-01-24 11:24:25 +00:00
libgcc libgcc: avoid mmap/munmap hooks in split-stack code on GNU/Linux 2020-04-03 14:58:27 -07:00
libgfortran Use au->lock exclusively for locking in async I/O. 2020-02-18 19:45:25 +01:00
libgo runtime: handle linux/arm64 signal register 2020-02-28 12:24:21 -08:00
libgomp Revert "[nvptx, libgomp] Update pr85381-{2,4}.c test-cases" [PR89713, PR94392] 2020-04-03 10:10:07 +02:00
libhsail-rt Add `--with-toolexeclibdir=' configuration option 2020-01-24 11:24:25 +00:00
libiberty Keep .GCC.command.line sections of LTO objetcs 2020-03-05 08:44:11 +01:00
libitm Use a non-empty test program to test ability to link. 2020-02-12 13:22:07 -08:00
libobjc Use a non-empty test program to test ability to link. 2020-02-12 13:22:07 -08:00
liboffloadmic Add `--with-toolexeclibdir=' configuration option 2020-01-24 11:24:25 +00:00
libphobos libphobos: Reset libtool_VERSION to 1:0:0 2020-03-16 17:04:18 +01:00
libquadmath Use a non-empty test program to test ability to link. 2020-02-12 13:22:07 -08:00
libsanitizer Darwin, libsanitizer: Adjust minimum supported Darwin version (PR93731). 2020-03-01 14:40:57 +00:00
libssp Use a non-empty test program to test ability to link. 2020-02-12 13:22:07 -08:00
libstdc++-v3 libstdc++: Fix std::to_address for debug iterators (PR 93960) 2020-04-03 10:42:20 +01:00
libvtv Add `--with-toolexeclibdir=' configuration option 2020-01-24 11:24:25 +00:00
lto-plugin API extension for binutils (type of symbols). 2020-03-19 16:56:27 +01:00
maintainer-scripts maintainer-scripts: Fix up gcc_release without -l, where mkdir was using umask 077 after migration 2020-03-12 18:30:16 +01:00
zlib Add `--with-toolexeclibdir=' configuration option 2020-01-24 11:24:25 +00:00
.dir-locals.el
.gitattributes Add *.md diff=md. 2020-01-15 14:29:53 +01:00
.gitignore Add .clangd and compile_commands.json to .gitignore. 2019-08-28 19:33:28 +00:00
ABOUT-NLS
ar-lib
ChangeLog configure - build libgomp by default for amdgcn 2020-03-09 17:00:39 +01:00
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config-ml.in MSP430: Add -fno-exceptions multilib 2019-12-11 19:19:50 +00:00
config.guess Update config.sub and config.guess. 2019-09-09 11:14:32 +02:00
config.rpath
config.sub Update config.sub and config.guess. 2019-09-09 11:14:32 +02:00
configure configure - build libgomp by default for amdgcn 2020-03-09 17:00:39 +01:00
configure.ac configure - build libgomp by default for amdgcn 2020-03-09 17:00:39 +01:00
COPYING
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libtool.m4 [ARM/FDPIC v6 02/24] [ARM] FDPIC: Handle arm*-*-uclinuxfdpiceabi in configure scripts 2019-09-10 09:37:00 +02:00
ltgcc.m4
ltmain.sh
ltoptions.m4
ltsugar.m4
ltversion.m4
lt~obsolete.m4
MAINTAINERS Update myself to MAINTAINERS 2020-03-11 23:32:40 -04:00
Makefile.def Sync top-level change from gdb 2019-06-15 21:32:03 +00:00
Makefile.in Makefile.tpl (HOST_EXPORTS): Add CXX_FOR_BUILD. 2019-08-23 15:37:22 -06:00
Makefile.tpl Makefile.tpl (HOST_EXPORTS): Add CXX_FOR_BUILD. 2019-08-23 15:37:22 -06:00
missing
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