[llvm] [BOLT] Add support for safe-icf (PR #116275)

[Alexander Yermolovich via llvm-commits]

ayermolo wrote:

> > > > g++ produces it for virtual destructors: Basic example:
> > > 
> > > 
> > > If it's virtual, could it be that you are looking at a vtable?
> > 
> > 
> > From example it's: _ZN7MyClassD1Ev --> MyClass::~MyClass()
> > Hope I am not missing something.
> 
> Is this reference located inside a vtable?

Oh I see.

Yes I think so:

```
	.type	_ZTV7MyClass, at object            # @_ZTV7MyClass
	.section	.rodata._ZTV7MyClass,"aG", at progbits,_ZTV7MyClass,comdat
	.weak	_ZTV7MyClass
	.p2align	3, 0x0
_ZTV7MyClass:
	.quad	0
	.quad	_ZTI7MyClass
	.quad	_ZN7MyClassD2Ev
	.quad	_ZN7MyClassD0Ev
	.size	_ZTV7MyClass, 32
```

https://github.com/llvm/llvm-project/pull/116275