[cfe-dev] Bug with -fvisibility-inlines-hidden flag

[Weitian Leung via cfe-dev]

Hi all,

Consider the following code (full source code can be found in attachment)

object.h
> #define _DESTRUCTOR_IN_HEADER
>
> class Object
> {
> public:
>     Object();
> #ifdef _DESTRUCTOR_IN_HEADER
>     ~Object()
>     {
>     }
> #else
>     ~Object();
> #endif
>
> private:
>     class Counter
>     {
>     public:
>         Counter()
>             : _count(0)
>         {
>             printf("Counter: %p %d\n", this, _count);
>         }
>
>         ~Counter()
>         {
>             printf("~Counter: %p %d\n", this, _count);
>         }
>
>         void operator++()    { ++_count; }
>         void operator--()    { --_count; }
>
>     private:
>         int _count;
>     };
>
>     class Foo
>     {
>     public:
>         Foo() { ++counter(); }
>         ~Foo() { --counter(); }
>
>     private:
>         Counter& counter()
>         {
>             static Counter s_counter;
>             return s_counter;
>         }
>     } foo;
> };
object.cpp
> #include "object.h"
>
> Object::Object()
> {
> }
>
> #ifndef _DESTRUCTOR_IN_HEADER
> Object::~Object()
> {
>
> }
> #endif

Build the source to a shared library (compile with 
-fvisibility-inlines-hidden flag),
uses in main (another module)
>     Object *obj = new Object;
>     delete obj;
you may see the strange output when running
> Counter: 0x7f2ded933efc 0
> Counter: 0x6012d4 0
> ~Counter: 0x6012d4 -1
> ~Counter: 0x7f2ded933efc 1

The Counter construct/destruct twice, the second one (Counter: 0x6012d4 
0) construct from
  delete obj > Object::Foo::~Foo() > Object::Foo::counter()

when comment out the line *#define _DESTRUCTOR_IN_HEADER *or remove the*
**-fvisibility-inlines-hidden* flag, it works as expected
remove the compile flag
> Counter: 0x6013a4 0
> ~Counter: 0x6013a4 0
comment out #define _DESTRUCTOR_IN_HEADER
> Counter: 0x7f1eaa16629c 0
> ~Counter: 0x7f1eaa16629c 0

A bit difference, as the address isn't the same (heap and stack)

this code works with GCC (as least 5.2 as my test) with or without the 
-fvisibility-inlines-hidden
flag, of course it works with MSVC too.

I don't known is this a bug with the flag or because the silly code 
makes it (as when constructor and
destructor defined in the same file, it works).

-- 
/Regards/
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