cmd/compile: make generated function code more consistent

There are a bunch of places where we generate functions: equality and
hash functions; method expression and promoted method wrappers; and
print/delete wrappers for defer/go statements.

This CL brings them in sync by:

1) Always using dclfunc and funcbody. Most were already using this,
but makepartialcall needed some changes.

2) Removing duplicate types.Markdcl/types.Popdcl calls. These are
already handled by dclfunc and funcbody.

3) Using structargs (already used by genwrapper) to construct new
param/result lists from existing types.

4) Always accessing the parameter ONAME nodes through Field.Nname
instead of poking into the ODCLFIELD. Also, since creating a slice of
the entire parameter list is common, extract this out into a
paramNnames helper function.

5) Add a Type.IsVariadic method to simplify identifying variadic
function types.

Passes toolstash-check -gcflags=-dwarf=false. DWARF output changes
because using structargs in makepartialcall changes the generated
parameter names.

Change-Id: I6661d3699afdbe7852ad60db5a4ec6eeb2b696e4
Reviewed-on: https://go-review.googlesource.com/108216
Run-TryBot: Matthew Dempsky <mdempsky@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Robert Griesemer <gri@golang.org>

1 files changed, 6 insertions, 0 deletions

diff --git a/src/cmd/compile/internal/types/type.go b/src/cmd/compile/internal/types/type.go
index f5e9237b81..55d0930ceb 100644
--- a/src/cmd/compile/internal/types/type.go
+++ b/src/cmd/compile/internal/types/type.go
@@ -710,6 +710,12 @@ func (t *Type) NumRecvs() int   { return t.FuncType().Receiver.NumFields() }
 func (t *Type) NumParams() int  { return t.FuncType().Params.NumFields() }
 func (t *Type) NumResults() int { return t.FuncType().Results.NumFields() }
 
+// IsVariadic reports whether function type t is variadic.
+func (t *Type) IsVariadic() bool {
+	n := t.NumParams()
+	return n > 0 && t.Params().Field(n-1).Isddd()
+}
+
 // Recv returns the receiver of function type t, if any.
 func (t *Type) Recv() *Field {
 	s := t.Recvs()