cmd/internal/obj: replace Addr.U struct {...} with Val interface{}

An interface{} is more in the spirit of the original union.
By my calculations, on 64-bit systems this reduces
Addr from 120 to 80 bytes, and Prog from 592 to 424 bytes.

Change-Id: I0d7b0981513c2a3c94c9ac76bb4f8816485b5a3c
Reviewed-on: https://go-review.googlesource.com/7744
Reviewed-by: Rob Pike <r@golang.org>

33 files changed, 164 insertions, 164 deletions

diff --git a/src/cmd/5g/ggen.go b/src/cmd/5g/ggen.go
index 52fe20bdc8..353817779a 100644
--- a/src/cmd/5g/ggen.go
+++ b/src/cmd/5g/ggen.go
@@ -16,7 +16,7 @@ func defframe(ptxt *obj.Prog) {
 	// fill in argument size, stack size
 	ptxt.To.Type = obj.TYPE_TEXTSIZE
 
-	ptxt.To.U.Argsize = int32(gc.Rnd(gc.Curfn.Type.Argwid, int64(gc.Widthptr)))
+	ptxt.To.Val = int32(gc.Rnd(gc.Curfn.Type.Argwid, int64(gc.Widthptr)))
 	frame := uint32(gc.Rnd(gc.Stksize+gc.Maxarg, int64(gc.Widthreg)))
 	ptxt.To.Offset = int64(frame)
 
diff --git a/src/cmd/6g/ggen.go b/src/cmd/6g/ggen.go
index efbbded1d3..f980593948 100644
--- a/src/cmd/6g/ggen.go
+++ b/src/cmd/6g/ggen.go
@@ -16,7 +16,7 @@ func defframe(ptxt *obj.Prog) {
 	// fill in argument size, stack size
 	ptxt.To.Type = obj.TYPE_TEXTSIZE
 
-	ptxt.To.U.Argsize = int32(gc.Rnd(gc.Curfn.Type.Argwid, int64(gc.Widthptr)))
+	ptxt.To.Val = int32(gc.Rnd(gc.Curfn.Type.Argwid, int64(gc.Widthptr)))
 	frame := uint32(gc.Rnd(gc.Stksize+gc.Maxarg, int64(gc.Widthreg)))
 	ptxt.To.Offset = int64(frame)
 
@@ -1095,7 +1095,7 @@ func expandchecks(firstp *obj.Prog) {
 		p1.From.Type = obj.TYPE_CONST
 		p1.From.Offset = 1 // likely
 		p1.To.Type = obj.TYPE_BRANCH
-		p1.To.U.Branch = p2.Link
+		p1.To.Val = p2.Link
 
 		// crash by write to memory address 0.
 		// if possible, since we know arg is 0, use 0(arg),
diff --git a/src/cmd/6g/peep.go b/src/cmd/6g/peep.go
index df780d4a36..849eab768f 100644
--- a/src/cmd/6g/peep.go
+++ b/src/cmd/6g/peep.go
@@ -1017,7 +1017,7 @@ loop:
 					if p.From.Node == p0.From.Node {
 						if p.From.Offset == p0.From.Offset {
 							if p.From.Scale == p0.From.Scale {
-								if p.From.Type == obj.TYPE_FCONST && p.From.U.Dval == p0.From.U.Dval {
+								if p.From.Type == obj.TYPE_FCONST && p.From.Val.(float64) == p0.From.Val.(float64) {
 									if p.From.Index == p0.From.Index {
 										excise(r)
 										goto loop
diff --git a/src/cmd/7g/ggen.go b/src/cmd/7g/ggen.go
index fe04bdf7c3..7eb913f22b 100644
--- a/src/cmd/7g/ggen.go
+++ b/src/cmd/7g/ggen.go
@@ -17,7 +17,7 @@ func defframe(ptxt *obj.Prog) {
 	// fill in argument size, stack size
 	ptxt.To.Type = obj.TYPE_TEXTSIZE
 
-	ptxt.To.U.Argsize = int32(gc.Rnd(gc.Curfn.Type.Argwid, int64(gc.Widthptr)))
+	ptxt.To.Val = int32(gc.Rnd(gc.Curfn.Type.Argwid, int64(gc.Widthptr)))
 	frame := uint32(gc.Rnd(gc.Stksize+gc.Maxarg, int64(gc.Widthreg)))
 	ptxt.To.Offset = int64(frame)
 
@@ -840,7 +840,7 @@ func expandchecks(firstp *obj.Prog) {
 		//p1->from.offset = 1; // likely
 		p1.To.Type = obj.TYPE_BRANCH
 
-		p1.To.U.Branch = p2.Link
+		p1.To.Val = p2.Link
 
 		// crash by write to memory address 0.
 		p2.As = arm64.AMOVD
diff --git a/src/cmd/8g/ggen.go b/src/cmd/8g/ggen.go
index c153c9380b..077b6579bb 100644
--- a/src/cmd/8g/ggen.go
+++ b/src/cmd/8g/ggen.go
@@ -16,7 +16,7 @@ func defframe(ptxt *obj.Prog) {
 	// fill in argument size, stack size
 	ptxt.To.Type = obj.TYPE_TEXTSIZE
 
-	ptxt.To.U.Argsize = int32(gc.Rnd(gc.Curfn.Type.Argwid, int64(gc.Widthptr)))
+	ptxt.To.Val = int32(gc.Rnd(gc.Curfn.Type.Argwid, int64(gc.Widthptr)))
 	frame := uint32(gc.Rnd(gc.Stksize+gc.Maxarg, int64(gc.Widthreg)))
 	ptxt.To.Offset = int64(frame)
 
@@ -1212,7 +1212,7 @@ func expandchecks(firstp *obj.Prog) {
 		p1.From.Type = obj.TYPE_CONST
 		p1.From.Offset = 1 // likely
 		p1.To.Type = obj.TYPE_BRANCH
-		p1.To.U.Branch = p2.Link
+		p1.To.Val = p2.Link
 
 		// crash by write to memory address 0.
 		// if possible, since we know arg is 0, use 0(arg),
diff --git a/src/cmd/8g/peep.go b/src/cmd/8g/peep.go
index 1967d5f736..2c9da4527c 100644
--- a/src/cmd/8g/peep.go
+++ b/src/cmd/8g/peep.go
@@ -797,7 +797,7 @@ loop:
 					if p.From.Node == p0.From.Node {
 						if p.From.Offset == p0.From.Offset {
 							if p.From.Scale == p0.From.Scale {
-								if p.From.Type == obj.TYPE_FCONST && p.From.U.Dval == p0.From.U.Dval {
+								if p.From.Type == obj.TYPE_FCONST && p.From.Val.(float64) == p0.From.Val.(float64) {
 									if p.From.Index == p0.From.Index {
 										excise(r)
 										goto loop
diff --git a/src/cmd/9g/ggen.go b/src/cmd/9g/ggen.go
index 6127619999..5919a79113 100644
--- a/src/cmd/9g/ggen.go
+++ b/src/cmd/9g/ggen.go
@@ -17,7 +17,7 @@ func defframe(ptxt *obj.Prog) {
 	// fill in argument size, stack size
 	ptxt.To.Type = obj.TYPE_TEXTSIZE
 
-	ptxt.To.U.Argsize = int32(gc.Rnd(gc.Curfn.Type.Argwid, int64(gc.Widthptr)))
+	ptxt.To.Val = int32(gc.Rnd(gc.Curfn.Type.Argwid, int64(gc.Widthptr)))
 	frame := uint32(gc.Rnd(gc.Stksize+gc.Maxarg, int64(gc.Widthreg)))
 	ptxt.To.Offset = int64(frame)
 
@@ -870,7 +870,7 @@ func expandchecks(firstp *obj.Prog) {
 		//p1->from.offset = 1; // likely
 		p1.To.Type = obj.TYPE_BRANCH
 
-		p1.To.U.Branch = p2.Link
+		p1.To.Val = p2.Link
 
 		// crash by write to memory address 0.
 		p2.As = ppc64.AMOVD
diff --git a/src/cmd/asm/internal/asm/asm.go b/src/cmd/asm/internal/asm/asm.go
index 883044c64c..811853b31a 100644
--- a/src/cmd/asm/internal/asm/asm.go
+++ b/src/cmd/asm/internal/asm/asm.go
@@ -161,7 +161,7 @@ func (p *Parser) asmText(word string, operands [][]lex.Token) {
 			// Argsize set below.
 		},
 	}
-	prog.To.U.Argsize = int32(argSize)
+	prog.To.Val = int32(argSize)
 
 	p.append(prog, "", true)
 }
@@ -406,7 +406,7 @@ func (p *Parser) branch(jmp, target *obj.Prog) {
 		Type:  obj.TYPE_BRANCH,
 		Index: 0,
 	}
-	jmp.To.U.Branch = target
+	jmp.To.Val = target
 }
 
 // asmInstruction assembles an instruction.
diff --git a/src/cmd/asm/internal/asm/parse.go b/src/cmd/asm/internal/asm/parse.go
index 2b6b97de50..81d7cccd0e 100644
--- a/src/cmd/asm/internal/asm/parse.go
+++ b/src/cmd/asm/internal/asm/parse.go
@@ -343,7 +343,7 @@ func (p *Parser) operand(a *obj.Addr) bool {
 				p.errorf("floating-point constant must be an immediate")
 			}
 			a.Type = obj.TYPE_FCONST
-			a.U.Dval = p.floatExpr()
+			a.Val = p.floatExpr()
 			// fmt.Printf("FCONST %s\n", obj.Dconv(&emptyProg, 0, a))
 			p.expect(scanner.EOF)
 			return true
@@ -357,7 +357,7 @@ func (p *Parser) operand(a *obj.Addr) bool {
 				p.errorf("string parse error: %s", err)
 			}
 			a.Type = obj.TYPE_SCONST
-			a.U.Sval = str
+			a.Val = str
 			// fmt.Printf("SCONST %s\n", obj.Dconv(&emptyProg, 0, a))
 			p.expect(scanner.EOF)
 			return true
diff --git a/src/cmd/internal/gc/gsubr.go b/src/cmd/internal/gc/gsubr.go
index 626a16b2ba..f5d76219a6 100644
--- a/src/cmd/internal/gc/gsubr.go
+++ b/src/cmd/internal/gc/gsubr.go
@@ -79,7 +79,7 @@ func Samereg(a *Node, b *Node) bool {
 func Gbranch(as int, t *Type, likely int) *obj.Prog {
 	p := Prog(as)
 	p.To.Type = obj.TYPE_BRANCH
-	p.To.U.Branch = nil
+	p.To.Val = nil
 	if as != obj.AJMP && likely != 0 && Thearch.Thechar != '9' && Thearch.Thechar != '7' {
 		p.From.Type = obj.TYPE_CONST
 		p.From.Offset = int64(bool2int(likely > 0))
@@ -400,7 +400,7 @@ func Naddr(a *obj.Addr, n *Node) {
 
 		case CTFLT:
 			a.Type = obj.TYPE_FCONST
-			a.U.Dval = mpgetflt(n.Val.U.Fval)
+			a.Val = mpgetflt(n.Val.U.Fval)
 
 		case CTINT,
 			CTRUNE:
@@ -585,7 +585,7 @@ func Patch(p *obj.Prog, to *obj.Prog) {
 	if p.To.Type != obj.TYPE_BRANCH {
 		Fatal("patch: not a branch")
 	}
-	p.To.U.Branch = to
+	p.To.Val = to
 	p.To.Offset = to.Pc
 }
 
@@ -593,8 +593,8 @@ func unpatch(p *obj.Prog) *obj.Prog {
 	if p.To.Type != obj.TYPE_BRANCH {
 		Fatal("unpatch: not a branch")
 	}
-	q := p.To.U.Branch
-	p.To.U.Branch = nil
+	q, _ := p.To.Val.(*obj.Prog)
+	p.To.Val = nil
 	p.To.Offset = 0
 	return q
 }
diff --git a/src/cmd/internal/gc/obj.go b/src/cmd/internal/gc/obj.go
index 787aaae28d..619f0ae905 100644
--- a/src/cmd/internal/gc/obj.go
+++ b/src/cmd/internal/gc/obj.go
@@ -355,7 +355,7 @@ func dsname(s *Sym, off int, t string) int {
 	p.From3.Offset = int64(len(t))
 
 	p.To.Type = obj.TYPE_SCONST
-	p.To.U.Sval = t
+	p.To.Val = t
 	return off + len(t)
 }
 
@@ -404,14 +404,14 @@ func gdatacomplex(nam *Node, cval *Mpcplx) {
 	p.From3.Type = obj.TYPE_CONST
 	p.From3.Offset = int64(w)
 	p.To.Type = obj.TYPE_FCONST
-	p.To.U.Dval = mpgetflt(&cval.Real)
+	p.To.Val = mpgetflt(&cval.Real)
 
 	p = Thearch.Gins(obj.ADATA, nam, nil)
 	p.From3.Type = obj.TYPE_CONST
 	p.From3.Offset = int64(w)
 	p.From.Offset += int64(w)
 	p.To.Type = obj.TYPE_FCONST
-	p.To.U.Dval = mpgetflt(&cval.Imag)
+	p.To.Val = mpgetflt(&cval.Imag)
 }
 
 func gdatastring(nam *Node, sval string) {
diff --git a/src/cmd/internal/gc/pgen.go b/src/cmd/internal/gc/pgen.go
index 6735c7df42..ab55911aab 100644
--- a/src/cmd/internal/gc/pgen.go
+++ b/src/cmd/internal/gc/pgen.go
@@ -114,8 +114,8 @@ func removevardef(firstp *obj.Prog) {
 			p.Link = p.Link.Link
 		}
 		if p.To.Type == obj.TYPE_BRANCH {
-			for p.To.U.Branch != nil && (p.To.U.Branch.As == obj.AVARDEF || p.To.U.Branch.As == obj.AVARKILL) {
-				p.To.U.Branch = p.To.U.Branch.Link
+			for p.To.Val.(*obj.Prog) != nil && (p.To.Val.(*obj.Prog).As == obj.AVARDEF || p.To.Val.(*obj.Prog).As == obj.AVARKILL) {
+				p.To.Val = p.To.Val.(*obj.Prog).Link
 			}
 		}
 	}
diff --git a/src/cmd/internal/gc/plive.go b/src/cmd/internal/gc/plive.go
index 5e5ae3090e..e0f85f9bba 100644
--- a/src/cmd/internal/gc/plive.go
+++ b/src/cmd/internal/gc/plive.go
@@ -423,12 +423,12 @@ func newcfg(firstp *obj.Prog) []*BasicBlock {
 	cfg = append(cfg, bb)
 	for p := firstp; p != nil; p = p.Link {
 		if p.To.Type == obj.TYPE_BRANCH {
-			if p.To.U.Branch == nil {
+			if p.To.Val == nil {
 				Fatal("prog branch to nil")
 			}
-			if p.To.U.Branch.Opt == nil {
-				p.To.U.Branch.Opt = newblock(p.To.U.Branch)
-				cfg = append(cfg, p.To.U.Branch.Opt.(*BasicBlock))
+			if p.To.Val.(*obj.Prog).Opt == nil {
+				p.To.Val.(*obj.Prog).Opt = newblock(p.To.Val.(*obj.Prog))
+				cfg = append(cfg, p.To.Val.(*obj.Prog).Opt.(*BasicBlock))
 			}
 
 			if p.As != obj.AJMP && p.Link != nil && p.Link.Opt == nil {
@@ -467,7 +467,7 @@ func newcfg(firstp *obj.Prog) []*BasicBlock {
 		}
 
 		if bb.last.To.Type == obj.TYPE_BRANCH {
-			addedge(bb, bb.last.To.U.Branch.Opt.(*BasicBlock))
+			addedge(bb, bb.last.To.Val.(*obj.Prog).Opt.(*BasicBlock))
 		}
 		if bb.last.Link != nil {
 			// Add a fall-through when the instruction is
diff --git a/src/cmd/internal/gc/popt.go b/src/cmd/internal/gc/popt.go
index d4cb4b676a..9070007dab 100644
--- a/src/cmd/internal/gc/popt.go
+++ b/src/cmd/internal/gc/popt.go
@@ -214,7 +214,7 @@ func chasejmp(p *obj.Prog, jmploop *int) *obj.Prog {
 			break
 		}
 
-		p = p.To.U.Branch
+		p = p.To.Val.(*obj.Prog)
 	}
 
 	return p
@@ -234,8 +234,8 @@ func mark(firstp *obj.Prog) {
 			break
 		}
 		p.Opt = alive
-		if p.As != obj.ACALL && p.To.Type == obj.TYPE_BRANCH && p.To.U.Branch != nil {
-			mark(p.To.U.Branch)
+		if p.As != obj.ACALL && p.To.Type == obj.TYPE_BRANCH && p.To.Val.(*obj.Prog) != nil {
+			mark(p.To.Val.(*obj.Prog))
 		}
 		if p.As == obj.AJMP || p.As == obj.ARET || p.As == obj.AUNDEF {
 			break
@@ -255,8 +255,8 @@ func fixjmp(firstp *obj.Prog) {
 		if Debug['R'] != 0 && Debug['v'] != 0 {
 			fmt.Printf("%v\n", p)
 		}
-		if p.As != obj.ACALL && p.To.Type == obj.TYPE_BRANCH && p.To.U.Branch != nil && p.To.U.Branch.As == obj.AJMP {
-			p.To.U.Branch = chasejmp(p.To.U.Branch, &jmploop)
+		if p.As != obj.ACALL && p.To.Type == obj.TYPE_BRANCH && p.To.Val.(*obj.Prog) != nil && p.To.Val.(*obj.Prog).As == obj.AJMP {
+			p.To.Val = chasejmp(p.To.Val.(*obj.Prog), &jmploop)
 			if Debug['R'] != 0 && Debug['v'] != 0 {
 				fmt.Printf("->%v\n", p)
 			}
@@ -307,7 +307,7 @@ func fixjmp(firstp *obj.Prog) {
 	if jmploop == 0 {
 		var last *obj.Prog
 		for p := firstp; p != nil; p = p.Link {
-			if p.As == obj.AJMP && p.To.Type == obj.TYPE_BRANCH && p.To.U.Branch == p.Link {
+			if p.As == obj.AJMP && p.To.Type == obj.TYPE_BRANCH && p.To.Val == p.Link {
 				if Debug['R'] != 0 && Debug['v'] != 0 {
 					fmt.Printf("del %v\n", p)
 				}
@@ -417,12 +417,12 @@ func Flowstart(firstp *obj.Prog, newData func() interface{}) *Graph {
 		}
 
 		if p.To.Type == obj.TYPE_BRANCH {
-			if p.To.U.Branch == nil {
+			if p.To.Val == nil {
 				Fatal("pnil %v", p)
 			}
-			f1 = p.To.U.Branch.Opt.(*Flow)
+			f1 = p.To.Val.(*obj.Prog).Opt.(*Flow)
 			if f1 == nil {
-				Fatal("fnil %v / %v", p, p.To.U.Branch)
+				Fatal("fnil %v / %v", p, p.To.Val.(*obj.Prog))
 			}
 			if f1 == f {
 				//fatal("self loop %P", p);
diff --git a/src/cmd/internal/gc/reg.go b/src/cmd/internal/gc/reg.go
index 1dd0ba75ce..d613bd1e00 100644
--- a/src/cmd/internal/gc/reg.go
+++ b/src/cmd/internal/gc/reg.go
@@ -1313,8 +1313,8 @@ brk:
 			p.Link = p.Link.Link
 		}
 		if p.To.Type == obj.TYPE_BRANCH {
-			for p.To.U.Branch != nil && p.To.U.Branch.As == obj.ANOP {
-				p.To.U.Branch = p.To.U.Branch.Link
+			for p.To.Val.(*obj.Prog) != nil && p.To.Val.(*obj.Prog).As == obj.ANOP {
+				p.To.Val = p.To.Val.(*obj.Prog).Link
 			}
 		}
 	}
diff --git a/src/cmd/internal/obj/arm/asm5.go b/src/cmd/internal/obj/arm/asm5.go
index 96074c70f5..942fc70ff7 100644
--- a/src/cmd/internal/obj/arm/asm5.go
+++ b/src/cmd/internal/obj/arm/asm5.go
@@ -1116,10 +1116,10 @@ func aclass(ctxt *obj.Link, a *obj.Addr) int {
 		return C_GOK
 
 	case obj.TYPE_FCONST:
-		if chipzero5(ctxt, a.U.Dval) >= 0 {
+		if chipzero5(ctxt, a.Val.(float64)) >= 0 {
 			return C_ZFCON
 		}
-		if chipfloat5(ctxt, a.U.Dval) >= 0 {
+		if chipfloat5(ctxt, a.Val.(float64)) >= 0 {
 			return C_SFCON
 		}
 		return C_LFCON
@@ -2259,7 +2259,7 @@ func asmout(ctxt *obj.Link, p *obj.Prog, o *Optab, out []uint32) {
 		}
 		o1 |= ((uint32(p.Scond) & C_SCOND) ^ C_SCOND_XOR) << 28
 		o1 |= (uint32(p.To.Reg) & 15) << 12
-		v := int32(chipfloat5(ctxt, p.From.U.Dval))
+		v := int32(chipfloat5(ctxt, p.From.Val.(float64)))
 		o1 |= (uint32(v) & 0xf) << 0
 		o1 |= (uint32(v) & 0xf0) << 12
 
diff --git a/src/cmd/internal/obj/arm/obj5.go b/src/cmd/internal/obj/arm/obj5.go
index 1f59c621c5..6b6e46b6a6 100644
--- a/src/cmd/internal/obj/arm/obj5.go
+++ b/src/cmd/internal/obj/arm/obj5.go
@@ -107,8 +107,8 @@ func progedit(ctxt *obj.Link, p *obj.Prog) {
 	// Rewrite float constants to values stored in memory.
 	switch p.As {
 	case AMOVF:
-		if p.From.Type == obj.TYPE_FCONST && chipfloat5(ctxt, p.From.U.Dval) < 0 && (chipzero5(ctxt, p.From.U.Dval) < 0 || p.Scond&C_SCOND != C_SCOND_NONE) {
-			f32 := float32(p.From.U.Dval)
+		if p.From.Type == obj.TYPE_FCONST && chipfloat5(ctxt, p.From.Val.(float64)) < 0 && (chipzero5(ctxt, p.From.Val.(float64)) < 0 || p.Scond&C_SCOND != C_SCOND_NONE) {
+			f32 := float32(p.From.Val.(float64))
 			i32 := math.Float32bits(f32)
 			literal := fmt.Sprintf("$f32.%08x", i32)
 			s := obj.Linklookup(ctxt, literal, 0)
@@ -125,8 +125,8 @@ func progedit(ctxt *obj.Link, p *obj.Prog) {
 		}
 
 	case AMOVD:
-		if p.From.Type == obj.TYPE_FCONST && chipfloat5(ctxt, p.From.U.Dval) < 0 && (chipzero5(ctxt, p.From.U.Dval) < 0 || p.Scond&C_SCOND != C_SCOND_NONE) {
-			i64 := math.Float64bits(p.From.U.Dval)
+		if p.From.Type == obj.TYPE_FCONST && chipfloat5(ctxt, p.From.Val.(float64)) < 0 && (chipzero5(ctxt, p.From.Val.(float64)) < 0 || p.Scond&C_SCOND != C_SCOND_NONE) {
+			i64 := math.Float64bits(p.From.Val.(float64))
 			literal := fmt.Sprintf("$f64.%016x", i64)
 			s := obj.Linklookup(ctxt, literal, 0)
 			if s.Type == 0 {
@@ -201,7 +201,7 @@ func preprocess(ctxt *obj.Link, cursym *obj.LSym) {
 		autoffset = 0
 	}
 	cursym.Locals = autoffset
-	cursym.Args = p.To.U.Argsize
+	cursym.Args = p.To.Val.(int32)
 
 	if ctxt.Debugzerostack != 0 {
 		if autoffset != 0 && p.From3.Offset&obj.NOSPLIT == 0 {
diff --git a/src/cmd/internal/obj/arm64/asm7.go b/src/cmd/internal/obj/arm64/asm7.go
index ba56f82df0..d8f39fe405 100644
--- a/src/cmd/internal/obj/arm64/asm7.go
+++ b/src/cmd/internal/obj/arm64/asm7.go
@@ -2625,7 +2625,7 @@ func asmout(ctxt *obj.Link, p *obj.Prog, o *Optab, out []uint32) {
 
 		var rf int
 		if p.From.Type == obj.TYPE_CONST {
-			rf = chipfloat7(ctxt, p.From.U.Dval)
+			rf = chipfloat7(ctxt, p.From.Val.(float64))
 			if rf < 0 || true {
 				ctxt.Diag("invalid floating-point immediate\n%v", p)
 				rf = 0
diff --git a/src/cmd/internal/obj/arm64/obj7.go b/src/cmd/internal/obj/arm64/obj7.go
index 0b92cfcaf1..dfba86ccb9 100644
--- a/src/cmd/internal/obj/arm64/obj7.go
+++ b/src/cmd/internal/obj/arm64/obj7.go
@@ -240,7 +240,7 @@ func progedit(ctxt *obj.Link, p *obj.Prog) {
 	switch p.As {
 	case AFMOVS:
 		if p.From.Type == obj.TYPE_FCONST {
-			f32 := float32(p.From.U.Dval)
+			f32 := float32(p.From.Val.(float64))
 			i32 := math.Float32bits(f32)
 			literal := fmt.Sprintf("$f32.%08x", uint32(i32))
 			s := obj.Linklookup(ctxt, literal, 0)
@@ -253,7 +253,7 @@ func progedit(ctxt *obj.Link, p *obj.Prog) {
 
 	case AFMOVD:
 		if p.From.Type == obj.TYPE_FCONST {
-			i64 := math.Float64bits(p.From.U.Dval)
+			i64 := math.Float64bits(p.From.Val.(float64))
 			literal := fmt.Sprintf("$f64.%016x", uint64(i64))
 			s := obj.Linklookup(ctxt, literal, 0)
 			s.Size = 8
@@ -480,7 +480,7 @@ func preprocess(ctxt *obj.Link, cursym *obj.LSym) {
 	textstksiz := p.To.Offset
 	aoffset := int32(textstksiz)
 
-	cursym.Args = p.To.U.Argsize
+	cursym.Args = p.To.Val.(int32)
 	cursym.Locals = int32(textstksiz)
 
 	/*
diff --git a/src/cmd/internal/obj/data.go b/src/cmd/internal/obj/data.go
index 6321ca4f2a..ab3e2096d0 100644
--- a/src/cmd/internal/obj/data.go
+++ b/src/cmd/internal/obj/data.go
@@ -75,16 +75,16 @@ func savedata(ctxt *Link, s *LSym, p *Prog, pn string) {
 			ctxt.Diag("unexpected %d-byte floating point constant", siz)
 
 		case 4:
-			flt := math.Float32bits(float32(p.To.U.Dval))
+			flt := math.Float32bits(float32(p.To.Val.(float64)))
 			ctxt.Arch.ByteOrder.PutUint32(s.P[off:], flt)
 
 		case 8:
-			flt := math.Float64bits(p.To.U.Dval)
+			flt := math.Float64bits(p.To.Val.(float64))
 			ctxt.Arch.ByteOrder.PutUint64(s.P[off:], flt)
 		}
 
 	case TYPE_SCONST:
-		copy(s.P[off:off+siz], p.To.U.Sval)
+		copy(s.P[off:off+siz], p.To.Val.(string))
 
 	case TYPE_CONST, TYPE_ADDR:
 		if p.To.Sym != nil || int(p.To.Type) == TYPE_ADDR {
diff --git a/src/cmd/internal/obj/link.go b/src/cmd/internal/obj/link.go
index 76dd72aa61..3b286af493 100644
--- a/src/cmd/internal/obj/link.go
+++ b/src/cmd/internal/obj/link.go
@@ -76,13 +76,13 @@ import "encoding/binary"
 //		Floating point constant value.
 //		Encoding:
 //			type = TYPE_FCONST
-//			u.dval = floating point value
+//			val = floating point value
 //
 //	$<string literal, up to 8 chars>
 //		String literal value (raw bytes used for DATA instruction).
 //		Encoding:
 //			type = TYPE_SCONST
-//			u.sval = string
+//			val = string
 //
 //	<register name>
 //		Any register: integer, floating point, control, segment, and so on.
@@ -94,7 +94,7 @@ import "encoding/binary"
 //	x(PC)
 //		Encoding:
 //			type = TYPE_BRANCH
-//			u.branch = Prog* reference OR ELSE offset = target pc (branch takes priority)
+//			val = Prog* reference OR ELSE offset = target pc (branch takes priority)
 //
 //	$±x-±y
 //		Final argument to TEXT, specifying local frame size x and argument size y.
@@ -106,7 +106,7 @@ import "encoding/binary"
 //		Encoding:
 //			type = TYPE_TEXTSIZE
 //			offset = x
-//			u.argsize = y
+//			val = int32(y)
 //
 //	reg<<shift, reg>>shift, reg->shift, reg@>shift
 //		Shifted register value, for ARM.
@@ -150,20 +150,21 @@ type Addr struct {
 	Index  int16
 	Scale  int16 // Sometimes holds a register.
 	Name   int8
-	Offset int64
-	Sym    *LSym
-	U      struct {
-		Sval    string
-		Dval    float64
-		Branch  *Prog
-		Argsize int32
-		Bits    uint64
-	}
-	Gotype *LSym
 	Class  int8
 	Etype  uint8
-	Node   interface{}
+	Offset int64
 	Width  int64
+	Sym    *LSym
+	Gotype *LSym
+
+	// argument value:
+	//	for TYPE_SCONST, a string
+	//	for TYPE_FCONST, a float64
+	//	for TYPE_BRANCH, a *Prog (optional)
+	//	for TYPE_TEXTSIZE, an int32 (optional)
+	Val interface{}
+
+	Node interface{} // for use by compiler
 }
 
 const (
@@ -198,13 +199,8 @@ const (
 // TODO(rsc): Describe TEXT/GLOBL flag in from3, DATA width in from3.
 type Prog struct {
 	Ctxt     *Link
-	Pc       int64
-	Lineno   int32
 	Link     *Prog
-	As       int16
-	Scond    uint8
 	From     Addr
-	Reg      int16
 	From3    Addr
 	To       Addr
 	To2      Addr
@@ -213,9 +209,14 @@ type Prog struct {
 	Pcond    *Prog
 	Comefrom *Prog
 	Pcrel    *Prog
+	Pc       int64
+	Lineno   int32
 	Spadj    int32
+	As       int16
+	Reg      int16
 	Mark     uint16
 	Optab    uint16
+	Scond    uint8
 	Back     uint8
 	Ft       uint8
 	F3t      uint8
diff --git a/src/cmd/internal/obj/pass.go b/src/cmd/internal/obj/pass.go
index 50d21e9e00..50dda94c8c 100644
--- a/src/cmd/internal/obj/pass.go
+++ b/src/cmd/internal/obj/pass.go
@@ -90,7 +90,7 @@ func checkaddr(ctxt *Link, p *Prog, a *Addr) {
 			return
 		}
 
-		if a.Reg != 0 || a.Scale != 0 || a.Name != 0 || a.Sym != nil || a.U.Bits != 0 {
+		if a.Reg != 0 || a.Scale != 0 || a.Name != 0 || a.Sym != nil || a.Val != nil {
 			break
 		}
 		return
@@ -111,7 +111,7 @@ func checkaddr(ctxt *Link, p *Prog, a *Addr) {
 		return
 
 	case TYPE_ADDR:
-		if a.U.Bits != 0 {
+		if a.Val != nil {
 			break
 		}
 		if a.Reg == 0 && a.Index == 0 && a.Scale == 0 && a.Name == 0 && a.Sym == nil {
@@ -120,13 +120,13 @@ 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.U.Bits != 0 {
+		if a.Index != 0 || a.Scale != 0 || a.Name != 0 || a.Sym != nil || a.Val != nil {
 			break
 		}
 		return
 
 	case TYPE_REGREG:
-		if a.Index != 0 || a.Scale != 0 || a.Name != 0 || a.Sym != nil || a.U.Bits != 0 {
+		if a.Index != 0 || a.Scale != 0 || a.Name != 0 || a.Sym != nil || a.Val != nil {
 			break
 		}
 		return
@@ -140,7 +140,7 @@ func checkaddr(ctxt *Link, p *Prog, a *Addr) {
 	// Expect sym and name to be set, nothing else.
 	// Technically more is allowed, but this is only used for *name(SB).
 	case TYPE_INDIR:
-		if a.Reg != 0 || a.Index != 0 || a.Scale != 0 || a.Name == 0 || a.Offset != 0 || a.Sym == nil || a.U.Bits != 0 {
+		if a.Reg != 0 || a.Index != 0 || a.Scale != 0 || a.Name == 0 || a.Offset != 0 || a.Sym == nil || a.Val != nil {
 			break
 		}
 		return
@@ -167,10 +167,9 @@ func linkpatch(ctxt *Link, sym *LSym) {
 		if p.To.Type != TYPE_BRANCH {
 			continue
 		}
-		if p.To.U.Branch != nil {
-			// TODO: Remove to.u.branch in favor of p->pcond.
-			p.Pcond = p.To.U.Branch
-
+		if p.To.Val != nil {
+			// TODO: Remove To.Val.(*Prog) in favor of p->pcond.
+			p.Pcond = p.To.Val.(*Prog)
 			continue
 		}
 
@@ -198,7 +197,7 @@ func linkpatch(ctxt *Link, sym *LSym) {
 			p.To.Type = TYPE_NONE
 		}
 
-		p.To.U.Branch = q
+		p.To.Val = q
 		p.Pcond = q
 	}
 
diff --git a/src/cmd/internal/obj/ppc64/obj9.go b/src/cmd/internal/obj/ppc64/obj9.go
index f47d81d77e..90fa725239 100644
--- a/src/cmd/internal/obj/ppc64/obj9.go
+++ b/src/cmd/internal/obj/ppc64/obj9.go
@@ -56,7 +56,7 @@ func progedit(ctxt *obj.Link, p *obj.Prog) {
 	switch p.As {
 	case AFMOVS:
 		if p.From.Type == obj.TYPE_FCONST {
-			f32 := float32(p.From.U.Dval)
+			f32 := float32(p.From.Val.(float64))
 			i32 := math.Float32bits(f32)
 			literal := fmt.Sprintf("$f32.%08x", i32)
 			s := obj.Linklookup(ctxt, literal, 0)
@@ -69,7 +69,7 @@ func progedit(ctxt *obj.Link, p *obj.Prog) {
 
 	case AFMOVD:
 		if p.From.Type == obj.TYPE_FCONST {
-			i64 := math.Float64bits(p.From.U.Dval)
+			i64 := math.Float64bits(p.From.Val.(float64))
 			literal := fmt.Sprintf("$f64.%016x", i64)
 			s := obj.Linklookup(ctxt, literal, 0)
 			s.Size = 8
@@ -130,7 +130,7 @@ func preprocess(ctxt *obj.Link, cursym *obj.LSym) {
 	p := cursym.Text
 	textstksiz := p.To.Offset
 
-	cursym.Args = p.To.U.Argsize
+	cursym.Args = p.To.Val.(int32)
 	cursym.Locals = int32(textstksiz)
 
 	/*
diff --git a/src/cmd/internal/obj/util.go b/src/cmd/internal/obj/util.go
index a2f3c1f8f1..b0d10b5fd5 100644
--- a/src/cmd/internal/obj/util.go
+++ b/src/cmd/internal/obj/util.go
@@ -389,8 +389,8 @@ func Dconv(p *Prog, a *Addr) string {
 			str = fmt.Sprintf("%s(SB)", a.Sym.Name)
 		} else if p != nil && p.Pcond != nil {
 			str = fmt.Sprintf("%d", p.Pcond.Pc)
-		} else if a.U.Branch != nil {
-			str = fmt.Sprintf("%d", a.U.Branch.Pc)
+		} else if a.Val != nil {
+			str = fmt.Sprintf("%d", a.Val.(*Prog).Pc)
 		} else {
 			str = fmt.Sprintf("%d(PC)", a.Offset)
 		}
@@ -412,14 +412,14 @@ func Dconv(p *Prog, a *Addr) string {
 		}
 
 	case TYPE_TEXTSIZE:
-		if a.U.Argsize == ArgsSizeUnknown {
+		if a.Val.(int32) == ArgsSizeUnknown {
 			str = fmt.Sprintf("$%d", a.Offset)
 		} else {
-			str = fmt.Sprintf("$%d-%d", a.Offset, a.U.Argsize)
+			str = fmt.Sprintf("$%d-%d", a.Offset, a.Val.(int32))
 		}
 
 	case TYPE_FCONST:
-		str = fmt.Sprintf("%.17g", a.U.Dval)
+		str = fmt.Sprintf("%.17g", a.Val.(float64))
 		// Make sure 1 prints as 1.0
 		if !strings.ContainsAny(str, ".e") {
 			str += ".0"
@@ -427,7 +427,7 @@ func Dconv(p *Prog, a *Addr) string {
 		str = fmt.Sprintf("$(%s)", str)
 
 	case TYPE_SCONST:
-		str = fmt.Sprintf("$%q", a.U.Sval)
+		str = fmt.Sprintf("$%q", a.Val.(string))
 
 	case TYPE_ADDR:
 		str = fmt.Sprintf("$%s", Mconv(a))
diff --git a/src/cmd/internal/obj/x86/obj6.go b/src/cmd/internal/obj/x86/obj6.go
index cf226d8672..6a0baa66a3 100644
--- a/src/cmd/internal/obj/x86/obj6.go
+++ b/src/cmd/internal/obj/x86/obj6.go
@@ -201,7 +201,7 @@ func progedit(ctxt *obj.Link, p *obj.Prog) {
 	// Convert AMOVSS $(0), Xx to AXORPS Xx, Xx
 	case AMOVSS:
 		if p.From.Type == obj.TYPE_FCONST {
-			if p.From.U.Dval == 0 {
+			if p.From.Val.(float64) == 0 {
 				if p.To.Type == obj.TYPE_REG && REG_X0 <= p.To.Reg && p.To.Reg <= REG_X15 {
 					p.As = AXORPS
 					p.From = p.To
@@ -227,7 +227,7 @@ func progedit(ctxt *obj.Link, p *obj.Prog) {
 		ACOMISS,
 		AUCOMISS:
 		if p.From.Type == obj.TYPE_FCONST {
-			f32 := float32(p.From.U.Dval)
+			f32 := float32(p.From.Val.(float64))
 			i32 := math.Float32bits(f32)
 			literal := fmt.Sprintf("$f32.%08x", i32)
 			s := obj.Linklookup(ctxt, literal, 0)
@@ -246,7 +246,7 @@ func progedit(ctxt *obj.Link, p *obj.Prog) {
 	case AMOVSD:
 		// Convert AMOVSD $(0), Xx to AXORPS Xx, Xx
 		if p.From.Type == obj.TYPE_FCONST {
-			if p.From.U.Dval == 0 {
+			if p.From.Val.(float64) == 0 {
 				if p.To.Type == obj.TYPE_REG && REG_X0 <= p.To.Reg && p.To.Reg <= REG_X15 {
 					p.As = AXORPS
 					p.From = p.To
@@ -272,7 +272,7 @@ func progedit(ctxt *obj.Link, p *obj.Prog) {
 		ACOMISD,
 		AUCOMISD:
 		if p.From.Type == obj.TYPE_FCONST {
-			i64 := math.Float64bits(p.From.U.Dval)
+			i64 := math.Float64bits(p.From.Val.(float64))
 			literal := fmt.Sprintf("$f64.%016x", i64)
 			s := obj.Linklookup(ctxt, literal, 0)
 			if s.Type == 0 {
@@ -361,7 +361,7 @@ func preprocess(ctxt *obj.Link, cursym *obj.LSym) {
 		bpsize = 0
 	}
 
-	textarg := int64(p.To.U.Argsize)
+	textarg := int64(p.To.Val.(int32))
 	cursym.Args = int32(textarg)
 	cursym.Locals = int32(p.To.Offset)
 
diff --git a/src/cmd/old5a/a.y b/src/cmd/old5a/a.y
index c1ca3beaa8..0ef8ae904c 100644
--- a/src/cmd/old5a/a.y
+++ b/src/cmd/old5a/a.y
@@ -376,28 +376,28 @@ textsize:
 		$$ = nullgen;
 		$$.Type = obj.TYPE_TEXTSIZE;
 		$$.Offset = int64($1)
-		$$.U.Argsize = obj.ArgsSizeUnknown;
+		$$.Val = int32(obj.ArgsSizeUnknown)
 	}
 |	'-' LCONST
 	{
 		$$ = nullgen;
 		$$.Type = obj.TYPE_TEXTSIZE;
 		$$.Offset = -int64($2)
-		$$.U.Argsize = obj.ArgsSizeUnknown;
+		$$.Val = int32(obj.ArgsSizeUnknown)
 	}
 |	LCONST '-' LCONST
 	{
 		$$ = nullgen;
 		$$.Type = obj.TYPE_TEXTSIZE;
 		$$.Offset = int64($1)
-		$$.U.Argsize = int32($3);
+		$$.Val = int32($3);
 	}
 |	'-' LCONST '-' LCONST
 	{
 		$$ = nullgen;
 		$$.Type = obj.TYPE_TEXTSIZE;
 		$$.Offset = -int64($2)
-		$$.U.Argsize = int32($4);
+		$$.Val = int32($4);
 	}
 
 cond:
@@ -449,7 +449,7 @@ ximm:	'$' con
 	{
 		$$ = nullgen;
 		$$.Type = obj.TYPE_SCONST;
-		$$.U.Sval = $2
+		$$.Val = $2
 	}
 |	fcon
 
@@ -458,13 +458,13 @@ fcon:
 	{
 		$$ = nullgen;
 		$$.Type = obj.TYPE_FCONST;
-		$$.U.Dval = $2;
+		$$.Val = $2;
 	}
 |	'$' '-' LFCONST
 	{
 		$$ = nullgen;
 		$$.Type = obj.TYPE_FCONST;
-		$$.U.Dval = -$3;
+		$$.Val = -$3;
 	}
 
 reglist:
diff --git a/src/cmd/old5a/y.go b/src/cmd/old5a/y.go
index a79f61d316..9f5988f8d7 100644
--- a/src/cmd/old5a/y.go
+++ b/src/cmd/old5a/y.go
@@ -981,7 +981,7 @@ yydefault:
 			yyVAL.addr = nullgen
 			yyVAL.addr.Type = obj.TYPE_TEXTSIZE
 			yyVAL.addr.Offset = int64(yyDollar[1].lval)
-			yyVAL.addr.U.Argsize = obj.ArgsSizeUnknown
+			yyVAL.addr.Val = int32(obj.ArgsSizeUnknown)
 		}
 	case 47:
 		yyDollar = yyS[yypt-2 : yypt+1]
@@ -990,7 +990,7 @@ yydefault:
 			yyVAL.addr = nullgen
 			yyVAL.addr.Type = obj.TYPE_TEXTSIZE
 			yyVAL.addr.Offset = -int64(yyDollar[2].lval)
-			yyVAL.addr.U.Argsize = obj.ArgsSizeUnknown
+			yyVAL.addr.Val = int32(obj.ArgsSizeUnknown)
 		}
 	case 48:
 		yyDollar = yyS[yypt-3 : yypt+1]
@@ -999,7 +999,7 @@ yydefault:
 			yyVAL.addr = nullgen
 			yyVAL.addr.Type = obj.TYPE_TEXTSIZE
 			yyVAL.addr.Offset = int64(yyDollar[1].lval)
-			yyVAL.addr.U.Argsize = int32(yyDollar[3].lval)
+			yyVAL.addr.Val = int32(yyDollar[3].lval)
 		}
 	case 49:
 		yyDollar = yyS[yypt-4 : yypt+1]
@@ -1008,7 +1008,7 @@ yydefault:
 			yyVAL.addr = nullgen
 			yyVAL.addr.Type = obj.TYPE_TEXTSIZE
 			yyVAL.addr.Offset = -int64(yyDollar[2].lval)
-			yyVAL.addr.U.Argsize = int32(yyDollar[4].lval)
+			yyVAL.addr.Val = int32(yyDollar[4].lval)
 		}
 	case 50:
 		yyDollar = yyS[yypt-0 : yypt+1]
@@ -1069,7 +1069,7 @@ yydefault:
 		{
 			yyVAL.addr = nullgen
 			yyVAL.addr.Type = obj.TYPE_SCONST
-			yyVAL.addr.U.Sval = yyDollar[2].sval
+			yyVAL.addr.Val = yyDollar[2].sval
 		}
 	case 60:
 		yyVAL.addr = yyS[yypt-0].addr
@@ -1079,7 +1079,7 @@ yydefault:
 		{
 			yyVAL.addr = nullgen
 			yyVAL.addr.Type = obj.TYPE_FCONST
-			yyVAL.addr.U.Dval = yyDollar[2].dval
+			yyVAL.addr.Val = yyDollar[2].dval
 		}
 	case 62:
 		yyDollar = yyS[yypt-3 : yypt+1]
@@ -1087,7 +1087,7 @@ yydefault:
 		{
 			yyVAL.addr = nullgen
 			yyVAL.addr.Type = obj.TYPE_FCONST
-			yyVAL.addr.U.Dval = -yyDollar[3].dval
+			yyVAL.addr.Val = -yyDollar[3].dval
 		}
 	case 63:
 		yyDollar = yyS[yypt-1 : yypt+1]
diff --git a/src/cmd/old6a/a.y b/src/cmd/old6a/a.y
index 376c040a55..46da420c96 100644
--- a/src/cmd/old6a/a.y
+++ b/src/cmd/old6a/a.y
@@ -454,31 +454,31 @@ imm:
 	{
 		$$ = nullgen;
 		$$.Type = obj.TYPE_SCONST;
-		$$.U.Sval = ($2+"\x00\x00\x00\x00\x00\x00\x00\x00")[:8]
+		$$.Val = ($2+"\x00\x00\x00\x00\x00\x00\x00\x00")[:8]
 	}
 |	'$' LFCONST
 	{
 		$$ = nullgen;
 		$$.Type = obj.TYPE_FCONST;
-		$$.U.Dval = $2;
+		$$.Val = $2;
 	}
 |	'$' '(' LFCONST ')'
 	{
 		$$ = nullgen;
 		$$.Type = obj.TYPE_FCONST;
-		$$.U.Dval = $3;
+		$$.Val = $3;
 	}
 |	'$' '(' '-' LFCONST ')'
 	{
 		$$ = nullgen;
 		$$.Type = obj.TYPE_FCONST;
-		$$.U.Dval = -$4;
+		$$.Val = -$4;
 	}
 |	'$' '-' LFCONST
 	{
 		$$ = nullgen;
 		$$.Type = obj.TYPE_FCONST;
-		$$.U.Dval = -$3;
+		$$.Val = -$3;
 	}
 
 mem:
@@ -653,28 +653,28 @@ textsize:
 		$$ = nullgen;
 		$$.Type = obj.TYPE_TEXTSIZE;
 		$$.Offset = $1;
-		$$.U.Argsize = obj.ArgsSizeUnknown;
+		$$.Val = int32(obj.ArgsSizeUnknown);
 	}
 |	'-' LCONST
 	{
 		$$ = nullgen;
 		$$.Type = obj.TYPE_TEXTSIZE;
 		$$.Offset = -$2;
-		$$.U.Argsize = obj.ArgsSizeUnknown;
+		$$.Val = int32(obj.ArgsSizeUnknown);
 	}
 |	LCONST '-' LCONST
 	{
 		$$ = nullgen;
 		$$.Type = obj.TYPE_TEXTSIZE;
 		$$.Offset = $1;
-		$$.U.Argsize = int32($3);
+		$$.Val = int32($3);
 	}
 |	'-' LCONST '-' LCONST
 	{
 		$$ = nullgen;
 		$$.Type = obj.TYPE_TEXTSIZE;
 		$$.Offset = -$2;
-		$$.U.Argsize = int32($4);
+		$$.Val = int32($4);
 	}
 
 expr:
diff --git a/src/cmd/old6a/y.go b/src/cmd/old6a/y.go
index 74fbcc765d..5738c5666b 100644
--- a/src/cmd/old6a/y.go
+++ b/src/cmd/old6a/y.go
@@ -1126,7 +1126,7 @@ yydefault:
 		{
 			yyVAL.addr = nullgen
 			yyVAL.addr.Type = obj.TYPE_SCONST
-			yyVAL.addr.U.Sval = (yyDollar[2].sval + "\x00\x00\x00\x00\x00\x00\x00\x00")[:8]
+			yyVAL.addr.Val = (yyDollar[2].sval + "\x00\x00\x00\x00\x00\x00\x00\x00")[:8]
 		}
 	case 85:
 		yyDollar = yyS[yypt-2 : yypt+1]
@@ -1134,7 +1134,7 @@ yydefault:
 		{
 			yyVAL.addr = nullgen
 			yyVAL.addr.Type = obj.TYPE_FCONST
-			yyVAL.addr.U.Dval = yyDollar[2].dval
+			yyVAL.addr.Val = yyDollar[2].dval
 		}
 	case 86:
 		yyDollar = yyS[yypt-4 : yypt+1]
@@ -1142,7 +1142,7 @@ yydefault:
 		{
 			yyVAL.addr = nullgen
 			yyVAL.addr.Type = obj.TYPE_FCONST
-			yyVAL.addr.U.Dval = yyDollar[3].dval
+			yyVAL.addr.Val = yyDollar[3].dval
 		}
 	case 87:
 		yyDollar = yyS[yypt-5 : yypt+1]
@@ -1150,7 +1150,7 @@ yydefault:
 		{
 			yyVAL.addr = nullgen
 			yyVAL.addr.Type = obj.TYPE_FCONST
-			yyVAL.addr.U.Dval = -yyDollar[4].dval
+			yyVAL.addr.Val = -yyDollar[4].dval
 		}
 	case 88:
 		yyDollar = yyS[yypt-3 : yypt+1]
@@ -1158,7 +1158,7 @@ yydefault:
 		{
 			yyVAL.addr = nullgen
 			yyVAL.addr.Type = obj.TYPE_FCONST
-			yyVAL.addr.U.Dval = -yyDollar[3].dval
+			yyVAL.addr.Val = -yyDollar[3].dval
 		}
 	case 89:
 		yyVAL.addr = yyS[yypt-0].addr
@@ -1373,7 +1373,7 @@ yydefault:
 			yyVAL.addr = nullgen
 			yyVAL.addr.Type = obj.TYPE_TEXTSIZE
 			yyVAL.addr.Offset = yyDollar[1].lval
-			yyVAL.addr.U.Argsize = obj.ArgsSizeUnknown
+			yyVAL.addr.Val = int32(obj.ArgsSizeUnknown)
 		}
 	case 119:
 		yyDollar = yyS[yypt-2 : yypt+1]
@@ -1382,7 +1382,7 @@ yydefault:
 			yyVAL.addr = nullgen
 			yyVAL.addr.Type = obj.TYPE_TEXTSIZE
 			yyVAL.addr.Offset = -yyDollar[2].lval
-			yyVAL.addr.U.Argsize = obj.ArgsSizeUnknown
+			yyVAL.addr.Val = int32(obj.ArgsSizeUnknown)
 		}
 	case 120:
 		yyDollar = yyS[yypt-3 : yypt+1]
@@ -1391,7 +1391,7 @@ yydefault:
 			yyVAL.addr = nullgen
 			yyVAL.addr.Type = obj.TYPE_TEXTSIZE
 			yyVAL.addr.Offset = yyDollar[1].lval
-			yyVAL.addr.U.Argsize = int32(yyDollar[3].lval)
+			yyVAL.addr.Val = int32(yyDollar[3].lval)
 		}
 	case 121:
 		yyDollar = yyS[yypt-4 : yypt+1]
@@ -1400,7 +1400,7 @@ yydefault:
 			yyVAL.addr = nullgen
 			yyVAL.addr.Type = obj.TYPE_TEXTSIZE
 			yyVAL.addr.Offset = -yyDollar[2].lval
-			yyVAL.addr.U.Argsize = int32(yyDollar[4].lval)
+			yyVAL.addr.Val = int32(yyDollar[4].lval)
 		}
 	case 122:
 		yyVAL.lval = yyS[yypt-0].lval
diff --git a/src/cmd/old8a/a.y b/src/cmd/old8a/a.y
index 07d9f4445b..fc12580e62 100644
--- a/src/cmd/old8a/a.y
+++ b/src/cmd/old8a/a.y
@@ -445,31 +445,31 @@ imm:
 	{
 		$$ = nullgen;
 		$$.Type = obj.TYPE_SCONST;
-		$$.U.Sval = $2
+		$$.Val = $2
 	}
 |	'$' LFCONST
 	{
 		$$ = nullgen;
 		$$.Type = obj.TYPE_FCONST;
-		$$.U.Dval = $2;
+		$$.Val = $2;
 	}
 |	'$' '(' LFCONST ')'
 	{
 		$$ = nullgen;
 		$$.Type = obj.TYPE_FCONST;
-		$$.U.Dval = $3;
+		$$.Val = $3;
 	}
 |	'$' '(' '-' LFCONST ')'
 	{
 		$$ = nullgen;
 		$$.Type = obj.TYPE_FCONST;
-		$$.U.Dval = -$4;
+		$$.Val = -$4;
 	}
 |	'$' '-' LFCONST
 	{
 		$$ = nullgen;
 		$$.Type = obj.TYPE_FCONST;
-		$$.U.Dval = -$3;
+		$$.Val = -$3;
 	}
 
 textsize:
@@ -478,28 +478,28 @@ textsize:
 		$$ = nullgen;
 		$$.Type = obj.TYPE_TEXTSIZE;
 		$$.Offset = $1;
-		$$.U.Argsize = obj.ArgsSizeUnknown;
+		$$.Val = int32(obj.ArgsSizeUnknown);
 	}
 |	'-' LCONST
 	{
 		$$ = nullgen;
 		$$.Type = obj.TYPE_TEXTSIZE;
 		$$.Offset = -$2;
-		$$.U.Argsize = obj.ArgsSizeUnknown;
+		$$.Val = int32(obj.ArgsSizeUnknown);
 	}
 |	LCONST '-' LCONST
 	{
 		$$ = nullgen;
 		$$.Type = obj.TYPE_TEXTSIZE;
 		$$.Offset = $1;
-		$$.U.Argsize = int32($3);
+		$$.Val = int32($3);
 	}
 |	'-' LCONST '-' LCONST
 	{
 		$$ = nullgen;
 		$$.Type = obj.TYPE_TEXTSIZE;
 		$$.Offset = -$2;
-		$$.U.Argsize = int32($4);
+		$$.Val = int32($4);
 	}
 
 
diff --git a/src/cmd/old8a/y.go b/src/cmd/old8a/y.go
index 407d22bde3..c727aca45a 100644
--- a/src/cmd/old8a/y.go
+++ b/src/cmd/old8a/y.go
@@ -1107,7 +1107,7 @@ yydefault:
 		{
 			yyVAL.addr = nullgen
 			yyVAL.addr.Type = obj.TYPE_SCONST
-			yyVAL.addr.U.Sval = yyDollar[2].sval
+			yyVAL.addr.Val = yyDollar[2].sval
 		}
 	case 83:
 		yyDollar = yyS[yypt-2 : yypt+1]
@@ -1115,7 +1115,7 @@ yydefault:
 		{
 			yyVAL.addr = nullgen
 			yyVAL.addr.Type = obj.TYPE_FCONST
-			yyVAL.addr.U.Dval = yyDollar[2].dval
+			yyVAL.addr.Val = yyDollar[2].dval
 		}
 	case 84:
 		yyDollar = yyS[yypt-4 : yypt+1]
@@ -1123,7 +1123,7 @@ yydefault:
 		{
 			yyVAL.addr = nullgen
 			yyVAL.addr.Type = obj.TYPE_FCONST
-			yyVAL.addr.U.Dval = yyDollar[3].dval
+			yyVAL.addr.Val = yyDollar[3].dval
 		}
 	case 85:
 		yyDollar = yyS[yypt-5 : yypt+1]
@@ -1131,7 +1131,7 @@ yydefault:
 		{
 			yyVAL.addr = nullgen
 			yyVAL.addr.Type = obj.TYPE_FCONST
-			yyVAL.addr.U.Dval = -yyDollar[4].dval
+			yyVAL.addr.Val = -yyDollar[4].dval
 		}
 	case 86:
 		yyDollar = yyS[yypt-3 : yypt+1]
@@ -1139,7 +1139,7 @@ yydefault:
 		{
 			yyVAL.addr = nullgen
 			yyVAL.addr.Type = obj.TYPE_FCONST
-			yyVAL.addr.U.Dval = -yyDollar[3].dval
+			yyVAL.addr.Val = -yyDollar[3].dval
 		}
 	case 87:
 		yyDollar = yyS[yypt-1 : yypt+1]
@@ -1148,7 +1148,7 @@ yydefault:
 			yyVAL.addr = nullgen
 			yyVAL.addr.Type = obj.TYPE_TEXTSIZE
 			yyVAL.addr.Offset = yyDollar[1].lval
-			yyVAL.addr.U.Argsize = obj.ArgsSizeUnknown
+			yyVAL.addr.Val = int32(obj.ArgsSizeUnknown)
 		}
 	case 88:
 		yyDollar = yyS[yypt-2 : yypt+1]
@@ -1157,7 +1157,7 @@ yydefault:
 			yyVAL.addr = nullgen
 			yyVAL.addr.Type = obj.TYPE_TEXTSIZE
 			yyVAL.addr.Offset = -yyDollar[2].lval
-			yyVAL.addr.U.Argsize = obj.ArgsSizeUnknown
+			yyVAL.addr.Val = int32(obj.ArgsSizeUnknown)
 		}
 	case 89:
 		yyDollar = yyS[yypt-3 : yypt+1]
@@ -1166,7 +1166,7 @@ yydefault:
 			yyVAL.addr = nullgen
 			yyVAL.addr.Type = obj.TYPE_TEXTSIZE
 			yyVAL.addr.Offset = yyDollar[1].lval
-			yyVAL.addr.U.Argsize = int32(yyDollar[3].lval)
+			yyVAL.addr.Val = int32(yyDollar[3].lval)
 		}
 	case 90:
 		yyDollar = yyS[yypt-4 : yypt+1]
@@ -1175,7 +1175,7 @@ yydefault:
 			yyVAL.addr = nullgen
 			yyVAL.addr.Type = obj.TYPE_TEXTSIZE
 			yyVAL.addr.Offset = -yyDollar[2].lval
-			yyVAL.addr.U.Argsize = int32(yyDollar[4].lval)
+			yyVAL.addr.Val = int32(yyDollar[4].lval)
 		}
 	case 91:
 		yyVAL.addr = yyS[yypt-0].addr
diff --git a/src/cmd/old9a/a.y b/src/cmd/old9a/a.y
index a6785df300..bdcd84d54d 100644
--- a/src/cmd/old9a/a.y
+++ b/src/cmd/old9a/a.y
@@ -846,28 +846,28 @@ textsize:
 		$$ = nullgen;
 		$$.Type = obj.TYPE_TEXTSIZE;
 		$$.Offset = int64($1)
-		$$.U.Argsize = obj.ArgsSizeUnknown;
+		$$.Val = int32(obj.ArgsSizeUnknown);
 	}
 |	'-' LCONST
 	{
 		$$ = nullgen;
 		$$.Type = obj.TYPE_TEXTSIZE;
 		$$.Offset = -int64($2)
-		$$.U.Argsize = obj.ArgsSizeUnknown;
+		$$.Val = int32(obj.ArgsSizeUnknown);
 	}
 |	LCONST '-' LCONST
 	{
 		$$ = nullgen;
 		$$.Type = obj.TYPE_TEXTSIZE;
 		$$.Offset = int64($1)
-		$$.U.Argsize = int32($3);
+		$$.Val = int32($3);
 	}
 |	'-' LCONST '-' LCONST
 	{
 		$$ = nullgen;
 		$$.Type = obj.TYPE_TEXTSIZE;
 		$$.Offset = -int64($2)
-		$$.U.Argsize = int32($4);
+		$$.Val = int32($4);
 	}
 
 ximm:
@@ -880,7 +880,7 @@ ximm:
 	{
 		$$ = nullgen;
 		$$.Type = obj.TYPE_SCONST;
-		$$.U.Sval = $2
+		$$.Val = $2
 	}
 
 fimm:
@@ -888,13 +888,13 @@ fimm:
 	{
 		$$ = nullgen;
 		$$.Type = obj.TYPE_FCONST;
-		$$.U.Dval = $2;
+		$$.Val = $2;
 	}
 |	'$' '-' LFCONST
 	{
 		$$ = nullgen;
 		$$.Type = obj.TYPE_FCONST;
-		$$.U.Dval = -$3;
+		$$.Val = -$3;
 	}
 
 imm:	'$' con
diff --git a/src/cmd/old9a/y.go b/src/cmd/old9a/y.go
index ecc9b9c7ac..65f612611f 100644
--- a/src/cmd/old9a/y.go
+++ b/src/cmd/old9a/y.go
@@ -1691,7 +1691,7 @@ yydefault:
 			yyVAL.addr = nullgen
 			yyVAL.addr.Type = obj.TYPE_TEXTSIZE
 			yyVAL.addr.Offset = int64(yyDollar[1].lval)
-			yyVAL.addr.U.Argsize = obj.ArgsSizeUnknown
+			yyVAL.addr.Val = int32(obj.ArgsSizeUnknown)
 		}
 	case 145:
 		yyDollar = yyS[yypt-2 : yypt+1]
@@ -1700,7 +1700,7 @@ yydefault:
 			yyVAL.addr = nullgen
 			yyVAL.addr.Type = obj.TYPE_TEXTSIZE
 			yyVAL.addr.Offset = -int64(yyDollar[2].lval)
-			yyVAL.addr.U.Argsize = obj.ArgsSizeUnknown
+			yyVAL.addr.Val = int32(obj.ArgsSizeUnknown)
 		}
 	case 146:
 		yyDollar = yyS[yypt-3 : yypt+1]
@@ -1709,7 +1709,7 @@ yydefault:
 			yyVAL.addr = nullgen
 			yyVAL.addr.Type = obj.TYPE_TEXTSIZE
 			yyVAL.addr.Offset = int64(yyDollar[1].lval)
-			yyVAL.addr.U.Argsize = int32(yyDollar[3].lval)
+			yyVAL.addr.Val = int32(yyDollar[3].lval)
 		}
 	case 147:
 		yyDollar = yyS[yypt-4 : yypt+1]
@@ -1718,7 +1718,7 @@ yydefault:
 			yyVAL.addr = nullgen
 			yyVAL.addr.Type = obj.TYPE_TEXTSIZE
 			yyVAL.addr.Offset = -int64(yyDollar[2].lval)
-			yyVAL.addr.U.Argsize = int32(yyDollar[4].lval)
+			yyVAL.addr.Val = int32(yyDollar[4].lval)
 		}
 	case 148:
 		yyDollar = yyS[yypt-2 : yypt+1]
@@ -1733,7 +1733,7 @@ yydefault:
 		{
 			yyVAL.addr = nullgen
 			yyVAL.addr.Type = obj.TYPE_SCONST
-			yyVAL.addr.U.Sval = yyDollar[2].sval
+			yyVAL.addr.Val = yyDollar[2].sval
 		}
 	case 150:
 		yyDollar = yyS[yypt-2 : yypt+1]
@@ -1741,7 +1741,7 @@ yydefault:
 		{
 			yyVAL.addr = nullgen
 			yyVAL.addr.Type = obj.TYPE_FCONST
-			yyVAL.addr.U.Dval = yyDollar[2].dval
+			yyVAL.addr.Val = yyDollar[2].dval
 		}
 	case 151:
 		yyDollar = yyS[yypt-3 : yypt+1]
@@ -1749,7 +1749,7 @@ yydefault:
 		{
 			yyVAL.addr = nullgen
 			yyVAL.addr.Type = obj.TYPE_FCONST
-			yyVAL.addr.U.Dval = -yyDollar[3].dval
+			yyVAL.addr.Val = -yyDollar[3].dval
 		}
 	case 152:
 		yyDollar = yyS[yypt-2 : yypt+1]