https://gcc.gnu.org/bugzilla/show_bug.cgi?id=103303
Bug ID: 103303
Summary: compiler have trouble to point to the correct
destructor address while for large align objects with
complex inheritance while destruct object
Product: gcc
Version: 8.2.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c++
Assignee: unassigned at gcc dot gnu.org
Reporter: wqpfelix at gmail dot com
Target Milestone: ---
Created attachment 51825
--> https://gcc.gnu.org/bugzilla/attachment.cgi?id=51825&action=edit
c++ code trigger the 0x8 offset for movaps
the error is reproduced on compiler explorer:
https://godbolt.org/z/v8roq3641
where I can trigger this problem while gcc after 8.1
more details:
while running with the following compiler
```sh
$Compiler/bin/g++ -v
Using built-in specs.
COLLECT_GCC=/net/binlib/build-kits/build-kit-20191029-x86_64-pc-linux-gnu-gcc-8.2.0-gcc82_u18_v3/bin/g++
COLLECT_LTO_WRAPPER=/net/binlib/build-kits/build-kit-20191029-x86_64-pc-linux-gnu-gcc-8.2.0-gcc82_u18_v3/bin/../libexec/gcc/x86_64-pc-linux-gnu/8.2.0/lto-wrapper
Target: x86_64-pc-linux-gnu
Configured with: .../gcc/configure --with-gmp={PathTo_gcc82_u18_v3}
--with-mpfr={PathTo_gcc82_u18_v3} --with-mpc={PathTo_gcc82_u18_v3}
--with-isl={PathTo_gcc82_u18_v3} --prefix={PathTo_gcc82_u18_v3}
--exec-prefix={PathTo_gcc82_u18_v3} --enable-languages=c,c++ --enable-shared
--enable-static --enable-threads=posix --disable-host-shared --enable-lto
--with-ld={PathTo_gcc82_u18_v3}/bin/ld --target=x86_64-pc-linux-gnu
--with-sysroot=/.
--with-gxx-include-dir={PathTo_gcc82_u18_v3}/include/libstdc++
--disable-multilib --verbose
Thread model: posix
gcc version 8.2.0 (GCC)
```
on C++ program with
```C++
#include <iostream>
#include <cstddef>
struct alignas(16) largeAligned{ // change to 8, no crash
uint32_t u_arr[128];
};
template<typename Base>
struct ICategory: public virtual Base{
ICategory(){
std::cout << __PRETTY_FUNCTION__ << std::endl;
}
};
struct PureInterfaceHandler{
virtual ~PureInterfaceHandler() = default;
};
template<typename...MsgCategoryNotifierS>
class TemplateNotifier
: public PureInterfaceHandler,
public MsgCategoryNotifierS...{
public:
TemplateNotifier() {
std::cout << __PRETTY_FUNCTION__ << std::endl;
}
virtual ~TemplateNotifier() {
std::cout << __PRETTY_FUNCTION__ << std::endl;
}
};
struct Base1{
Base1(){
std::cout << __PRETTY_FUNCTION__ << std::endl;
}
virtual ~Base1(){
std::cout << __PRETTY_FUNCTION__ << std::endl;
}
largeAligned aligned1;
};
struct Base2{
Base2(){
std::cout << __PRETTY_FUNCTION__ << std::endl;
}
virtual ~Base2(){
std::cout << __PRETTY_FUNCTION__ << std::endl;
}
largeAligned aligned2;
};
using Category2 = ICategory<Base1>;
using Category1 = ICategory<Base2>;
struct ProblematicNotifier: TemplateNotifier<Category1, Category2>{};
int main(){
static_assert(alignof(ProblematicNotifier) == 16, "128 is great" );
static_assert( alignof(std::max_align_t) == 16, "16? is great" );
ProblematicNotifier* objPtr = new ProblematicNotifier();
delete objPtr;
std::cout << "Done" << std::endl;
}
```
with:
$Compiler/bin/g++ -I $Compiler/include -I $Compiler/include/libstdc++
crash.cpp -O3
I found:
Program received signal SIGSEGV, Segmentation fault.
0x000000000040228a in ProblematicNotifier::~ProblematicNotifier() ()
on instruction:
0x40228a <_ZN19ProblematicNotifierD0Ev+202> movaps %xmm0,0x8(%rbx)
where (gdb) x/i $rbx
0x417e70: mov $0x34,%al
it looks like compiler generates
movaps with offset 0x8 while handling aligned object, while is not expected for
movaps
