[dev.regabi] cmd/compile: remove extra typ field in Name struct

Noticed the typ field was duplicated, since it is also in miniExpr inside Name.

Also clarified the comments for Func, now that it is actually the ODCLFUNC node.

Change-Id: Ia483a0ad34bb409cd92c43d4ae0a6852f9e4f644
Reviewed-on: https://go-review.googlesource.com/c/go/+/274619
Run-TryBot: Dan Scales <danscales@google.com>
TryBot-Result: Go Bot <gobot@golang.org>
Trust: Dan Scales <danscales@google.com>
Reviewed-by: Russ Cox <rsc@golang.org>

src/cmd/compile/internal/ir/func.go

@@ -17,13 +17,14 @@ import (
 //
 // There are multiple nodes that represent a Func in the IR.
 //
-// The ONAME node (Func.Name) is used for plain references to it.
-// The ODCLFUNC node (Func.Decl) is used for its declaration code.
-// The OCLOSURE node (Func.Closure) is used for a reference to a
+// The ONAME node (Func.Nname) is used for plain references to it.
+// The ODCLFUNC node (the Func itself) is used for its declaration code.
+// The OCLOSURE node (Func.OClosure) is used for a reference to a
 // function literal.
 //
-// A Func for an imported function will have only an ONAME node.
-// A declared function or method has an ONAME and an ODCLFUNC.
+// An imported function will have an ONAME node which points to a Func
+// with an empty body.
+// A declared function or method has an ODCLFUNC (the Func itself) and an ONAME.
 // A function literal is represented directly by an OCLOSURE, but it also
 // has an ODCLFUNC (and a matching ONAME) representing the compiled
 // underlying form of the closure, which accesses the captured variables
@@ -44,8 +45,8 @@ import (
 // the method name is stored in Sym instead of Right.
 // Each OCALLPART ends up being implemented as a new
 // function, a bit like a closure, with its own ODCLFUNC.
-// The OCALLPART has uses n.Func to record the linkage to
-// the generated ODCLFUNC (as n.Func.Decl), but there is no
+// The OCALLPART uses n.Func to record the linkage to
+// the generated ODCLFUNC, but there is no
 // pointer from the Func back to the OCALLPART.
 type Func struct {
 	miniNode

src/cmd/compile/internal/ir/name.go

@@ -21,7 +21,6 @@ type Name struct {
 	flags      bitset16
 	pragma     PragmaFlag // int16
 	sym        *types.Sym
-	typ        *types.Type
 	fn         *Func
 	offset     int64
 	val        constant.Value

src/cmd/compile/internal/ir/sizeof_test.go

@@ -21,7 +21,7 @@ func TestSizeof(t *testing.T) {
 		_64bit uintptr     // size on 64bit platforms
 	}{
 		{Func{}, 168, 288},
-		{Name{}, 128, 224},
+		{Name{}, 124, 216},
 	}
 
 	for _, tt := range tests {