Updated mangling specs

[Daveed Vandevoorde]

mendell at ca.ibm.com wrote:
> 
> Our template/standard guy thinks that this is not essential.  His words:
> 
>    My understanding of 14.5.5.1 is that it says that this mangling is not
>    required.  Paragraphs 6 to 8 define equivalent and functionally
>    equivalent expressions and function templates.
> 
>    'I + 10' and 'I + 1 + 2 + 3 + 4' are not equivalent but they are
>    functionally equivalent.
>
>    I think the mangling described below could be used to make all
>    nonequivalent functions disctinct, but these paragraphs state that only
>    functionally equivalent function template are distinct.

That only goes for the nondependent constant expressions (you're free to
evaluate them or not).

However, if the depend components of the expression differ, the template
signatures differ.

Consider the following example:

	// file 1:
	template<int I> int f(A<I+1>::X) { return 1; }
	template void f<1>(A<2>::X);

	// file 2:
	template<int I> int f(A<2*I>::X) { return 2; }
	template void f<1>(A<2>::X);

Two distinct functions are instantiated in this program and that is fine.
So we must be able to differentiate them.

This is in fact what paragraph 5 of 14.5.5.1 says:

	When an expression that references a template parameter is used in
	the function parameter list or the return type in the declaration of
	a function template, the expression that references the template
	parameter is part of the signature of the function template. This is
	necessary to permit a declaration of a function template in one
	translation unit to be linked with another declaration of the function
	template in another translation unit and, conversely, to ensure that
	function templates that are intended to be distinct are not linked
	with one another. [Example: 

	      template <int I, int J> A<I+J> f(A<I>, A<J>);   //  #1
	      template <int K, int L> A<K+L> f(A<K>, A<L>);   //  same as #1
	      template <int I, int J> A<I-J> f(A<I>, A<J>);   //  different from #1

	--- end example] [Note: Most expressions that use template parameters
	use non-type template parameters, but it is possible for an expression
	to reference a type parameter. For example, a template type parameter
	can be used in the sizeof operator. ] 


	Daveed