mirror of
git://gcc.gnu.org/git/gcc.git
synced 2025-03-25 15:20:54 +08:00
4cf6b06cb5
For -fsanitize=vptr, we insert a NULL store into the vptr instead of just adding a CLOBBER of this. build_clobber_this makes the CLOBBER conditional on in_charge (implicit) parameter whenever CLASSTYPE_VBASECLASSES, but when adding this conditionalization to the -fsanitize=vptr code in PR87095, I wanted it to catch some more cases when the class has CLASSTYPE_VBASECLASSES, but the vptr is still not shared with something else, otherwise the sanitization would be less effective. The following testcase shows that the chosen test that CLASSTYPE_PRIMARY_BINFO is non-NULL and has BINFO_VIRTUAL_P set wasn't sufficient, the D class has still sizeof(D) == sizeof(void*) and thus contains just a single vptr, but while in B::~B() this results in the vptr not being cleared, in C::~C() this condition isn't true, as CLASSTYPE_PRIMARY_BINFO in that case is B and is not BINFO_VIRTUAL_P, so it clears the vptr, but the D::~D() dtor after invoking C::~C() invokes A::~A() with an already cleared vptr, which is then reported. The following patch is just a shot in the dark, keep looking through CLASSTYPE_PRIMARY_BINFO until we find BINFO_VIRTUAL_P, but it works on the existing testcase as well as this new one. 2020-04-08 Jakub Jelinek <jakub@redhat.com> PR c++/94325 * decl.c (begin_destructor_body): For CLASSTYPE_VBASECLASSES class dtors, if CLASSTYPE_PRIMARY_BINFO is non-NULL, but not BINFO_VIRTUAL_P, look at CLASSTYPE_PRIMARY_BINFO of its BINFO_TYPE if it is not BINFO_VIRTUAL_P, and so on. * g++.dg/ubsan/vptr-15.C: New test.
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.