cmd/compile/internal/gc: remove dead code

Remove unused functions spotted by honnef.co/go/unused.

Change-Id: Iabf3b201215ce21e420a60f4ef2679b36231eda7
Reviewed-on: https://go-review.googlesource.com/29132
Run-TryBot: Dave Cheney <dave@cheney.net>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

src/cmd/compile/internal/gc/cgen.go

-// Copyright 2009 The Go Authors. All rights reserved.
-// Use of this source code is governed by a BSD-style
-// license that can be found in the LICENSE file.
-
-package gc
-
-import "cmd/internal/sys"
-
-// hasHMUL64 reports whether the architecture supports 64-bit
-// signed and unsigned high multiplication (OHMUL).
-func hasHMUL64() bool {
-	switch Ctxt.Arch.Family {
-	case sys.AMD64, sys.S390X, sys.ARM64:
-		return true
-	case sys.ARM, sys.I386, sys.MIPS64, sys.PPC64:
-		return false
-	}
-	Fatalf("unknown architecture")
-	return false
-}
-
-// hasRROTC64 reports whether the architecture supports 64-bit
-// rotate through carry instructions (ORROTC).
-func hasRROTC64() bool {
-	switch Ctxt.Arch.Family {
-	case sys.AMD64:
-		return true
-	case sys.ARM, sys.ARM64, sys.I386, sys.MIPS64, sys.PPC64, sys.S390X:
-		return false
-	}
-	Fatalf("unknown architecture")
-	return false
-}
-
-func hasRightShiftWithCarry() bool {
-	switch Ctxt.Arch.Family {
-	case sys.ARM64:
-		return true
-	case sys.AMD64, sys.ARM, sys.I386, sys.MIPS64, sys.PPC64, sys.S390X:
-		return false
-	}
-	Fatalf("unknown architecture")
-	return false
-}
-
-func hasAddSetCarry() bool {
-	switch Ctxt.Arch.Family {
-	case sys.ARM64:
-		return true
-	case sys.AMD64, sys.ARM, sys.I386, sys.MIPS64, sys.PPC64, sys.S390X:
-		return false
-	}
-	Fatalf("unknown architecture")
-	return false
-}

src/cmd/compile/internal/gc/gen.go

@@ -189,104 +189,6 @@ func clearlabels() {
 	labellist = labellist[:0]
 }
 
-func newlab(n *Node) *Label {
-	s := n.Left.Sym
-	lab := s.Label
-	if lab == nil {
-		lab = new(Label)
-		lab.Sym = s
-		s.Label = lab
-		if n.Used {
-			lab.Used = true
-		}
-		labellist = append(labellist, lab)
-	}
-
-	if n.Op == OLABEL {
-		if lab.Def != nil {
-			Yyerror("label %v already defined at %v", s, lab.Def.Line())
-		} else {
-			lab.Def = n
-		}
-	} else {
-		lab.Use = append(lab.Use, n)
-	}
-
-	return lab
-}
-
-// There is a copy of checkgoto in the new SSA backend.
-// Please keep them in sync.
-func checkgoto(from *Node, to *Node) {
-	if from.Sym == to.Sym {
-		return
-	}
-
-	nf := 0
-	for fs := from.Sym; fs != nil; fs = fs.Link {
-		nf++
-	}
-	nt := 0
-	for fs := to.Sym; fs != nil; fs = fs.Link {
-		nt++
-	}
-	fs := from.Sym
-	for ; nf > nt; nf-- {
-		fs = fs.Link
-	}
-	if fs != to.Sym {
-		lno := lineno
-		setlineno(from)
-
-		// decide what to complain about.
-		// prefer to complain about 'into block' over declarations,
-		// so scan backward to find most recent block or else dcl.
-		var block *Sym
-
-		var dcl *Sym
-		ts := to.Sym
-		for ; nt > nf; nt-- {
-			if ts.Pkg == nil {
-				block = ts
-			} else {
-				dcl = ts
-			}
-			ts = ts.Link
-		}
-
-		for ts != fs {
-			if ts.Pkg == nil {
-				block = ts
-			} else {
-				dcl = ts
-			}
-			ts = ts.Link
-			fs = fs.Link
-		}
-
-		if block != nil {
-			Yyerror("goto %v jumps into block starting at %v", from.Left.Sym, linestr(block.Lastlineno))
-		} else {
-			Yyerror("goto %v jumps over declaration of %v at %v", from.Left.Sym, dcl, linestr(dcl.Lastlineno))
-		}
-		lineno = lno
-	}
-}
-
-func stmtlabel(n *Node) *Label {
-	if n.Sym != nil {
-		lab := n.Sym.Label
-		if lab != nil {
-			if lab.Def != nil {
-				if lab.Def.Name.Defn == n {
-					return lab
-				}
-			}
-		}
-	}
-	return nil
-}
-
 // make a new off the books
 func Tempname(nn *Node, t *Type) {
 	if Curfn == nil {
@@ -328,26 +230,3 @@ func temp(t *Type) *Node {
 	n.Sym.Def.Used = true
 	return n.Orig
 }
-
-func checklabels() {
-	for _, lab := range labellist {
-		if lab.Def == nil {
-			for _, n := range lab.Use {
-				yyerrorl(n.Lineno, "label %v not defined", lab.Sym)
-			}
-			continue
-		}
-
-		if lab.Use == nil && !lab.Used {
-			yyerrorl(lab.Def.Lineno, "label %v defined and not used", lab.Sym)
-			continue
-		}
-
-		if lab.Gotopc != nil {
-			Fatalf("label %v never resolved", lab.Sym)
-		}
-		for _, n := range lab.Use {
-			checkgoto(n, lab.Def)
-		}
-	}
-}

src/cmd/compile/internal/gc/gsubr.go

@@ -255,14 +255,6 @@ func ggloblLSym(s *obj.LSym, width int32, flags int16) {
 	p.From3.Offset = int64(flags)
 }
 
-func gjmp(to *obj.Prog) *obj.Prog {
-	p := Gbranch(obj.AJMP, nil, 0)
-	if to != nil {
-		Patch(p, to)
-	}
-	return p
-}
-
 func gtrack(s *Sym) {
 	p := Thearch.Gins(obj.AUSEFIELD, nil, nil)
 	p.From.Type = obj.TYPE_MEM
@@ -270,10 +262,6 @@ func gtrack(s *Sym) {
 	p.From.Sym = Linksym(s)
 }
 
-func gused(n *Node) {
-	Thearch.Gins(obj.ANOP, n, nil) // used
-}
-
 func Isfat(t *Type) bool {
 	if t != nil {
 		switch t.Etype {
@@ -655,16 +643,6 @@ func Patch(p *obj.Prog, to *obj.Prog) {
 	p.To.Offset = to.Pc
 }
 
-func unpatch(p *obj.Prog) *obj.Prog {
-	if p.To.Type != obj.TYPE_BRANCH {
-		Fatalf("unpatch: not a branch")
-	}
-	q, _ := p.To.Val.(*obj.Prog)
-	p.To.Val = nil
-	p.To.Offset = 0
-	return q
-}
-
 var reg [100]int       // count of references to reg
 var regstk [100][]byte // allocation sites, when -v is given