Commit Graph

2 Commits

Author SHA1 Message Date
Reid Kleckner
e0ad0fd826 Change inalloca rules to make it only apply to the last parameter
This makes things a lot easier, because we can now talk about the
"argument allocation", which allocates all the memory for the call in
one shot.

The only functional change is to the verifier for a feature that hasn't
shipped yet.

llvm-svn: 199434
2014-01-16 22:59:24 +00:00
Reid Kleckner
f795c3e4a9 Begin adding docs and IR-level support for the inalloca attribute
The inalloca attribute is designed to support passing C++ objects by
value in the Microsoft C++ ABI.  It behaves the same as byval, except
that it always implies that the argument is in memory and that the bytes
are never copied.  This attribute allows the caller to take the address
of an outgoing argument's memory and execute arbitrary code to store
into it.

This patch adds basic IR support, docs, and verification.  It does not
attempt to implement any lowering or fix any possibly broken transforms.

When this patch lands, a complete description of this feature should
appear at http://llvm.org/docs/InAlloca.html .

Differential Revision: http://llvm-reviews.chandlerc.com/D2173

llvm-svn: 197645
2013-12-19 02:14:12 +00:00