https://gcc.gnu.org/bugzilla/show_bug.cgi?id=94325
Bug ID: 94325
Summary: [UBSAN] "invalid vptr" false positive for virtual
inheritance with -fno-sanitize-recover=all
Product: gcc
Version: 9.2.1
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c++
Assignee: unassigned at gcc dot gnu.org
Reporter: jaroslaw.melzer.gcc at gmail dot com
Target Milestone: ---
Created attachment 48111
--> https://gcc.gnu.org/bugzilla/attachment.cgi?id=48111&action=edit
reproducer code
See attached: ubsan-gcc.ii
Program ubsan-gcc compiled with options:
g++ -fsanitize=undefined -fno-sanitize-recover=all ubsan-gcc.ii
exits with following false positive:
ubsan-gcc.cpp:12:7: runtime error: member call on address 0x7ffcdd8c9800 which
does not point to an object of type 'DE'
0x7ffcdd8c9800: note: object has invalid vptr
17 56 00 00 00 00 00 00 00 00 00 00 00 76 43 93 7b 4b c2 bf 30 71 eb 2f 17
56 00 00 e3 41 18 cc
^~~~~~~~~~~~~~~~~~~~~~~
invalid vptr
May be related to https://gcc.gnu.org/bugzilla/show_bug.cgi?id=87095
This error doesn't manifest without -fno-sanitize-recover=all
gcc -v
Using built-in specs.
COLLECT_GCC=gcc
COLLECT_LTO_WRAPPER=/usr/lib/gcc/x86_64-linux-gnu/9/lto-wrapper
OFFLOAD_TARGET_NAMES=nvptx-none:hsa
OFFLOAD_TARGET_DEFAULT=1
Target: x86_64-linux-gnu
Configured with: ../src/configure -v --with-pkgversion='Ubuntu 9.2.1-9ubuntu2'
--with-bugurl=file:///usr/share/doc/gcc-9/README.Bugs
--enable-languages=c,ada,c++,go,brig,d,fortran,objc,obj-c++,gm2 --prefix=/usr
--with-gcc-major-version-only --program-suffix=-9
--program-prefix=x86_64-linux-gnu- --enable-shared --enable-linker-build-id
--libexecdir=/usr/lib --without-included-gettext --enable-threads=posix
--libdir=/usr/lib --enable-nls --enable-bootstrap --enable-clocale=gnu
--enable-libstdcxx-debug --enable-libstdcxx-time=yes
--with-default-libstdcxx-abi=new --enable-gnu-unique-object
--disable-vtable-verify --enable-plugin --enable-default-pie --with-system-zlib
--with-target-system-zlib=auto --enable-multiarch --disable-werror
--with-arch-32=i686 --with-abi=m64 --with-multilib-list=m32,m64,mx32
--enable-multilib --with-tune=generic --enable-offload-targets=nvptx-none,hsa
--without-cuda-driver --enable-checking=release --build=x86_64-linux-gnu
--host=x86_64-linux-gnu --target=x86_64-linux-gnu
Thread model: posix
gcc version 9.2.1 20191008 (Ubuntu 9.2.1-9ubuntu2)
