Virtual inheritance segfault

[llvmbot]

Bugzilla Link	11124
Resolution	FIXED
Resolved on	Oct 13, 2011 21:30
Version	2.9
OS	Linux
Reporter	LLVM Bugzilla Contributor
CC	@DougGregor,@efriedma-quic

Extended Description

The following C++ code gives a segfault when executed.

struct Base
{
const int text;
Base():text(1) {}
Base(int aText)
: text(aText) {}
};
struct SubA : public virtual Base
{
protected:
int x;
public:
SubA(int aX)
: x(aX) {}
};
class SubB : public virtual Base
{};
struct Diamond : public SubA, public SubB
{
Diamond(int text)
: Base(text), SubA(5), SubB() {}

void printText()
{
    if(text != 2)
      __builtin_abort();
    if(x!=5)
      __builtin_abort();
}

};

int main(int, char**)
{
Diamond x(2);
x.printText();
}

Incidentally, the same problem existed as a regression in gcc:
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=50618

Compilation was done on clang version 2.9 (tags/RELEASE_29/final).
Target: x86_64-unknown-linux-gnu.
Default Arch Linux distribution.

[efriedma-quic]

Yes, CodeGenFunction::EmitCXXConstructExpr is null-initializing the base using EmitNullInitialization, which isn't appropriate to use for a base class. This will require a bit of refactoring...

[efriedma-quic]

r141933.