Fun with parameter attributes: For several of the "synthetic" parameters added to D functions, we can apply noalias and nocapture. They are sret parameters, 'nest' pointers passed to nested functions, and _argptr: Nocapture: - Sret and nest are nocapture because they don't represent D-level variables, and thus the callee can't (validly) obtain a pointer to them, let alone keep it around after it returns. - _argptr is nocapture because although the callee has access to it as a pointer, that pointer is invalidated when it returns. All three are noalias because they're function-local variables - Sret and _argptr are noalias because they're freshly alloca'd memory only used for a single function call that's not allowed to keep an aliasing pointer to it around (since the parameter is nocapture). - 'Nest' is noalias because the callee only ever has access to one such pointer per parent function, and every parent function has a different one. This commit also ensures attributes set on sret, _arguments and _argptr are propagated to calls to such functions. It also adds one exception to the general rule that attributes on function types should propagate to calls: the type of a delegate's function pointer has a 'nest' parameter, but this can either be a true 'nest' (for delegates to nested functions) or a 'this' (for delegates to member functions). Since 'this' is neither noalias nor nocapture, and there's generally no way to tell which one it is, we remove these attributes at the call site if the callee is a delegate.

		The D Programming Language
		Compiler Front End Source
		Copyright (c) 1999-2002, by Digital Mars
		www.digitalmars.com
		All Rights Reserved


This is the source code to the front end Digital Mars D compiler.
It covers the lexical analysis, parsing, and semantic analysis
of the D Programming Language defined in the documents at
www.digitalmars.com/d/

The optimizer, code generator, and object file generator are not part
of this source, hence the source does not currently constitute a complete,
compilable program. However, many people have expressed a strong interested
in producing a D compiler with the GNU compiler sources. This release should
enable that.

These sources are free, they are redistributable and modifiable
under the terms of the GNU General Public License (attached as gpl.txt),
or the Artistic License (attached as artistic.txt).

It does not apply to anything else distributed by Digital Mars,
including D compiler executables.

-Walter Bright