I found a bug in latest Xcode 7.0 that annoys us very much in our company because it makes most of our C++ code not debuggable. After lots of experiment, I was able to reproduce it with a minimum amount of code.
In some cases, it is impossible to see members inside a C++ class on LLDB. It seems that three conditions must be present for that bug to appear:
- the class is forward declared
- the class has a
virtualmethod - the class is declared inside a precompiled header
I am asking whether somebody else already knowns about that bug and what is the recommended procedure to report that bug (to LLVM or Apple ?).
Steps to reproduce:
Create two source files with their content:
header.h
#ifndef HEADER_INCLUDED
#define HEADER_INCLUDED
class A; // forward declaration, has an effect on bug
class A
{
public :
virtual ~A() {}
protected:
int doYouSeeMe;
};
#endif
PCHAndFDbug.cpp
#include "header.h"
int main()
{
A* a = new A();
return 0;
}
Create a small Xcode 7 project with these two files. header.h must be set as a precompiled header (Prefix header setting in Xcode). As a reference, I am using Premake to generate that project and here is the premake5.lua source:
solution "PCHAndFDbug"
configurations {"Debug"}
xcodebuildsettings { MACOSX_DEPLOYMENT_TARGET = "10.7" }
project "WithPCH"
language "C++"
files {"PCHAndFDbug.cpp", "header.h"}
kind "ConsoleApp"
pchheader "header.h"
project "WithoutPCH"
language "C++"
files {"PCHAndFDbug.cpp", "header.h"}
kind "ConsoleApp"
Place a breakpoint on the return 0 statement. Check if you can see member doYouSeeMe in a variable.
