cmd/internal/obj: clean up checkaddr

Coalesce identical cases.
Give it a proper doc comment.
Fix comment locations.
Update/delete old comments.

Passes toolstash-check -all.

Change-Id: I88d9cf20e6e04b0c1c6583e92cd96335831f183f
Reviewed-on: https://go-review.googlesource.com/38442
Run-TryBot: Josh Bleecher Snyder <josharian@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Dave Cheney <dave@cheney.net>
Reviewed-by: Cherry Zhang <cherryyz@google.com>

diff --git a/src/cmd/internal/obj/pass.go b/src/cmd/internal/obj/pass.go
index 644f42cab01b2f6580678ea82d3b359df9e327ff..9794a109c24793cecde0769f05c3bd19f91a7896 100644 (file)
--- a/src/cmd/internal/obj/pass.go
+++ b/src/cmd/internal/obj/pass.go
@@ -49,31 +49,23 @@ func brloop(ctxt *Link, p *Prog) *Prog {
        return q
 }
 
+// checkaddr checks that a has an expected encoding, especially TYPE_CONST vs TYPE_ADDR.
 func checkaddr(ctxt *Link, p *Prog, a *Addr) {
-       // Check expected encoding, especially TYPE_CONST vs TYPE_ADDR.
        switch a.Type {
-       case TYPE_NONE:
+       case TYPE_NONE, TYPE_REGREG2, TYPE_REGLIST:
                return
 
-       case TYPE_BRANCH:
+       case TYPE_BRANCH, TYPE_TEXTSIZE:
                if a.Reg != 0 || a.Index != 0 || a.Scale != 0 || a.Name != 0 {
                        break
                }
                return
 
-       case TYPE_TEXTSIZE:
-               if a.Reg != 0 || a.Index != 0 || a.Scale != 0 || a.Name != 0 {
-                       break
-               }
-               return
-
-               //if(a->u.bits != 0)
-       //      break;
        case TYPE_MEM:
                return
 
-               // TODO(rsc): After fixing SHRQ, check a->index != 0 too.
        case TYPE_CONST:
+               // TODO(rsc): After fixing SHRQ, check a.Index != 0 too.
                if a.Name != 0 || a.Sym != nil || a.Reg != 0 {
                        ctxt.Diag("argument is TYPE_CONST, should be TYPE_ADDR, in %v", p)
                        return
@@ -90,9 +82,9 @@ func checkaddr(ctxt *Link, p *Prog, a *Addr) {
                }
                return
 
-       // TODO(rsc): After fixing PINSRQ, check a->offset != 0 too.
-       // TODO(rsc): After fixing SHRQ, check a->index != 0 too.
        case TYPE_REG:
+               // TODO(rsc): After fixing PINSRQ, check a.Offset != 0 too.
+               // TODO(rsc): After fixing SHRQ, check a.Index != 0 too.
                if a.Scale != 0 || a.Name != 0 || a.Sym != nil {
                        break
                }
@@ -107,27 +99,15 @@ func checkaddr(ctxt *Link, p *Prog, a *Addr) {
                }
                return
 
-       case TYPE_SHIFT:
-               if a.Index != 0 || a.Scale != 0 || a.Name != 0 || a.Sym != nil || a.Val != nil {
-                       break
-               }
-               return
-
-       case TYPE_REGREG:
+       case TYPE_SHIFT, TYPE_REGREG:
                if a.Index != 0 || a.Scale != 0 || a.Name != 0 || a.Sym != nil || a.Val != nil {
                        break
                }
                return
 
-       case TYPE_REGREG2:
-               return
-
-       case TYPE_REGLIST:
-               return
-
-       // Expect sym and name to be set, nothing else.
-       // Technically more is allowed, but this is only used for *name(SB).
        case TYPE_INDIR:
+               // Expect sym and name to be set, nothing else.
+               // Technically more is allowed, but this is only used for *name(SB).
                if a.Reg != 0 || a.Index != 0 || a.Scale != 0 || a.Name == 0 || a.Offset != 0 || a.Sym == nil || a.Val != nil {
                        break
                }