cmd/compile: rework handling of udiv on ARM

Instead of populating the aux symbol
of CALLudiv during rewrite rules,
populate it during genssa.

This simplifies the rewrite rules.
It also removes all remaining calls
to ctxt.Lookup from any rewrite rules.
This is a first step towards removing
ctxt from ssa.Cache entirely,
and also a first step towards converting
the obj.LSym.Version field into a boolean.
It should also speed up compilation.

Also, move func udiv into package runtime.
That's where it is anyway,
and it lets udiv look and act like the rest of
the runtime support functions.

Change-Id: I41462a632c14fdc41f61b08049ec13cd80a87bfe
Reviewed-on: https://go-review.googlesource.com/41191
Run-TryBot: Josh Bleecher Snyder <josharian@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Cherry Zhang <cherryyz@google.com>
Reviewed-by: Matthew Dempsky <mdempsky@google.com>

src/cmd/compile/internal/arm/ssa.go

@@ -622,7 +622,10 @@ func ssaGenValue(s *gc.SSAGenState, v *ssa.Value) {
 		p.From.Offset = v.AuxInt
 		p.To.Type = obj.TYPE_REG
 		p.To.Reg = v.Reg()
-	case ssa.OpARMCALLstatic, ssa.OpARMCALLclosure, ssa.OpARMCALLinter, ssa.OpARMCALLudiv:
+	case ssa.OpARMCALLstatic, ssa.OpARMCALLclosure, ssa.OpARMCALLinter:
+		s.Call(v)
+	case ssa.OpARMCALLudiv:
+		v.Aux = gc.Udiv
 		s.Call(v)
 	case ssa.OpARMDUFFZERO:
 		p := s.Prog(obj.ADUFFZERO)

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

@@ -270,5 +270,6 @@ var (
 	writeBarrier,
 	writebarrierptr,
 	typedmemmove,
-	typedmemclr *obj.LSym
+	typedmemclr,
+	Udiv *obj.LSym
 )

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

@@ -91,6 +91,7 @@ func initssaconfig() {
 	writebarrierptr = Sysfunc("writebarrierptr")
 	typedmemmove = Sysfunc("typedmemmove")
 	typedmemclr = Sysfunc("typedmemclr")
+	Udiv = Sysfunc("udiv")
 }
 
 // buildssa builds an SSA function.

src/cmd/compile/internal/ssa/gen/ARM.rules

@@ -34,12 +34,12 @@
 (Mul32uhilo x y) -> (MULLU x y)
 
 (Div32 x y) ->
-	(SUB (XOR <types.UInt32>                                                                  // negate the result if one operand is negative
-		(Select0 <types.UInt32> (CALLudiv {config.ctxt.Lookup("udiv", 0)}
+	(SUB (XOR <types.UInt32>                                                        // negate the result if one operand is negative
+		(Select0 <types.UInt32> (CALLudiv
 			(SUB <types.UInt32> (XOR x <types.UInt32> (Signmask x)) (Signmask x))   // negate x if negative
 			(SUB <types.UInt32> (XOR y <types.UInt32> (Signmask y)) (Signmask y)))) // negate y if negative
 		(Signmask (XOR <types.UInt32> x y))) (Signmask (XOR <types.UInt32> x y)))
-(Div32u x y) -> (Select0 <types.UInt32> (CALLudiv {config.ctxt.Lookup("udiv", 0)} x y))
+(Div32u x y) -> (Select0 <types.UInt32> (CALLudiv x y))
 (Div16 x y) -> (Div32 (SignExt16to32 x) (SignExt16to32 y))
 (Div16u x y) -> (Div32u (ZeroExt16to32 x) (ZeroExt16to32 y))
 (Div8 x y) -> (Div32 (SignExt8to32 x) (SignExt8to32 y))
@@ -48,12 +48,12 @@
 (Div64F x y) -> (DIVD x y)
 
 (Mod32 x y) ->
-	(SUB (XOR <types.UInt32>                                                                  // negate the result if x is negative
-		(Select1 <types.UInt32> (CALLudiv {config.ctxt.Lookup("udiv", 0)}
+	(SUB (XOR <types.UInt32>                                                        // negate the result if x is negative
+		(Select1 <types.UInt32> (CALLudiv
 			(SUB <types.UInt32> (XOR <types.UInt32> x (Signmask x)) (Signmask x))   // negate x if negative
 			(SUB <types.UInt32> (XOR <types.UInt32> y (Signmask y)) (Signmask y)))) // negate y if negative
 		(Signmask x)) (Signmask x))
-(Mod32u x y) -> (Select1 <types.UInt32> (CALLudiv {config.ctxt.Lookup("udiv", 0)} x y))
+(Mod32u x y) -> (Select1 <types.UInt32> (CALLudiv x y))
 (Mod16 x y) -> (Mod32 (SignExt16to32 x) (SignExt16to32 y))
 (Mod16u x y) -> (Mod32u (ZeroExt16to32 x) (ZeroExt16to32 y))
 (Mod8 x y) -> (Mod32 (SignExt8to32 x) (SignExt8to32 y))

src/cmd/compile/internal/ssa/gen/ARMOps.go

@@ -152,10 +152,7 @@ func init() {
 			},
 			clobberFlags: true,
 			typ:          "(UInt32,UInt32)",
-			aux:          "SymOff",
-			// TODO(mdempsky): Should this be true?
-			call:      false,
-			symEffect: "None",
+			call:         false, // TODO(mdempsky): Should this be true?
 		},
 
 		{name: "ADDS", argLength: 2, reg: gp21carry, asm: "ADD", commutative: true}, // arg0 + arg1, set carry flag

src/cmd/compile/internal/ssa/opGen.go

@@ -8151,10 +8151,8 @@ var opcodeTable = [...]opInfo{
 	},
 	{
 		name:         "CALLudiv",
-		auxType:      auxSymOff,
 		argLen:       2,
 		clobberFlags: true,
-		symEffect:    SymNone,
 		reg: regInfo{
 			inputs: []inputInfo{
 				{0, 2}, // R1

src/cmd/compile/internal/ssa/rewriteARM.go

@@ -13582,13 +13582,11 @@ func rewriteValueARM_OpDiv16u(v *Value) bool {
 func rewriteValueARM_OpDiv32(v *Value) bool {
 	b := v.Block
 	_ = b
-	config := b.Func.Config
-	_ = config
 	types := &b.Func.Config.Types
 	_ = types
 	// match: (Div32 x y)
 	// cond:
-	// result: (SUB (XOR <types.UInt32> 		(Select0 <types.UInt32> (CALLudiv {config.ctxt.Lookup("udiv", 0)} 			(SUB <types.UInt32> (XOR x <types.UInt32> (Signmask x)) (Signmask x)) 			(SUB <types.UInt32> (XOR y <types.UInt32> (Signmask y)) (Signmask y)))) 		(Signmask (XOR <types.UInt32> x y))) (Signmask (XOR <types.UInt32> x y)))
+	// result: (SUB (XOR <types.UInt32> 		(Select0 <types.UInt32> (CALLudiv 			(SUB <types.UInt32> (XOR x <types.UInt32> (Signmask x)) (Signmask x)) 			(SUB <types.UInt32> (XOR y <types.UInt32> (Signmask y)) (Signmask y)))) 		(Signmask (XOR <types.UInt32> x y))) (Signmask (XOR <types.UInt32> x y)))
 	for {
 		x := v.Args[0]
 		y := v.Args[1]
@@ -13596,7 +13594,6 @@ func rewriteValueARM_OpDiv32(v *Value) bool {
 		v0 := b.NewValue0(v.Pos, OpARMXOR, types.UInt32)
 		v1 := b.NewValue0(v.Pos, OpSelect0, types.UInt32)
 		v2 := b.NewValue0(v.Pos, OpARMCALLudiv, MakeTuple(types.UInt32, types.UInt32))
-		v2.Aux = config.ctxt.Lookup("udiv", 0)
 		v3 := b.NewValue0(v.Pos, OpARMSUB, types.UInt32)
 		v4 := b.NewValue0(v.Pos, OpARMXOR, types.UInt32)
 		v4.AddArg(x)
@@ -13653,20 +13650,17 @@ func rewriteValueARM_OpDiv32F(v *Value) bool {
 func rewriteValueARM_OpDiv32u(v *Value) bool {
 	b := v.Block
 	_ = b
-	config := b.Func.Config
-	_ = config
 	types := &b.Func.Config.Types
 	_ = types
 	// match: (Div32u x y)
 	// cond:
-	// result: (Select0 <types.UInt32> (CALLudiv {config.ctxt.Lookup("udiv", 0)} x y))
+	// result: (Select0 <types.UInt32> (CALLudiv x y))
 	for {
 		x := v.Args[0]
 		y := v.Args[1]
 		v.reset(OpSelect0)
 		v.Type = types.UInt32
 		v0 := b.NewValue0(v.Pos, OpARMCALLudiv, MakeTuple(types.UInt32, types.UInt32))
-		v0.Aux = config.ctxt.Lookup("udiv", 0)
 		v0.AddArg(x)
 		v0.AddArg(y)
 		v.AddArg(v0)
@@ -15088,13 +15082,11 @@ func rewriteValueARM_OpMod16u(v *Value) bool {
 func rewriteValueARM_OpMod32(v *Value) bool {
 	b := v.Block
 	_ = b
-	config := b.Func.Config
-	_ = config
 	types := &b.Func.Config.Types
 	_ = types
 	// match: (Mod32 x y)
 	// cond:
-	// result: (SUB (XOR <types.UInt32> 		(Select1 <types.UInt32> (CALLudiv {config.ctxt.Lookup("udiv", 0)} 			(SUB <types.UInt32> (XOR <types.UInt32> x (Signmask x)) (Signmask x)) 			(SUB <types.UInt32> (XOR <types.UInt32> y (Signmask y)) (Signmask y)))) 		(Signmask x)) (Signmask x))
+	// result: (SUB (XOR <types.UInt32> 		(Select1 <types.UInt32> (CALLudiv 			(SUB <types.UInt32> (XOR <types.UInt32> x (Signmask x)) (Signmask x)) 			(SUB <types.UInt32> (XOR <types.UInt32> y (Signmask y)) (Signmask y)))) 		(Signmask x)) (Signmask x))
 	for {
 		x := v.Args[0]
 		y := v.Args[1]
@@ -15102,7 +15094,6 @@ func rewriteValueARM_OpMod32(v *Value) bool {
 		v0 := b.NewValue0(v.Pos, OpARMXOR, types.UInt32)
 		v1 := b.NewValue0(v.Pos, OpSelect1, types.UInt32)
 		v2 := b.NewValue0(v.Pos, OpARMCALLudiv, MakeTuple(types.UInt32, types.UInt32))
-		v2.Aux = config.ctxt.Lookup("udiv", 0)
 		v3 := b.NewValue0(v.Pos, OpARMSUB, types.UInt32)
 		v4 := b.NewValue0(v.Pos, OpARMXOR, types.UInt32)
 		v4.AddArg(x)
@@ -15140,20 +15131,17 @@ func rewriteValueARM_OpMod32(v *Value) bool {
 func rewriteValueARM_OpMod32u(v *Value) bool {
 	b := v.Block
 	_ = b
-	config := b.Func.Config
-	_ = config
 	types := &b.Func.Config.Types
 	_ = types
 	// match: (Mod32u x y)
 	// cond:
-	// result: (Select1 <types.UInt32> (CALLudiv {config.ctxt.Lookup("udiv", 0)} x y))
+	// result: (Select1 <types.UInt32> (CALLudiv x y))
 	for {
 		x := v.Args[0]
 		y := v.Args[1]
 		v.reset(OpSelect1)
 		v.Type = types.UInt32
 		v0 := b.NewValue0(v.Pos, OpARMCALLudiv, MakeTuple(types.UInt32, types.UInt32))
-		v0.Aux = config.ctxt.Lookup("udiv", 0)
 		v0.AddArg(x)
 		v0.AddArg(y)
 		v.AddArg(v0)

src/cmd/vet/all/whitelist/arm.txt

@@ -19,6 +19,7 @@ runtime/duff_arm.s: [arm] duffcopy: function duffcopy missing Go declaration
 runtime/tls_arm.s: [arm] save_g: function save_g missing Go declaration
 runtime/tls_arm.s: [arm] load_g: function load_g missing Go declaration
 runtime/tls_arm.s: [arm] _initcgo: function _initcgo missing Go declaration
+runtime/vlop_arm.s: [arm] udiv: function udiv missing Go declaration
 
 // Clearer using FP than SP, but that requires named offsets.
 runtime/asm_arm.s: [arm] rt0_go: use of 4(R13) points beyond argument frame

src/runtime/vlop_arm.s

@@ -106,7 +106,7 @@ TEXT runtime·_sfloatpanic(SB),NOSPLIT,$-4
 	MOVW	g_sigpc(g), LR
 	B	runtime·sigpanic(SB)
 
-// func udiv(n, d uint32) (q, r uint32)
+// func runtime·udiv(n, d uint32) (q, r uint32)
 // compiler knowns the register usage of this function
 // Reference: 
 // Sloss, Andrew et. al; ARM System Developer's Guide: Designing and Optimizing System Software
@@ -118,7 +118,7 @@ TEXT runtime·_sfloatpanic(SB),NOSPLIT,$-4
 #define Ra	R11
 
 // Be careful: Ra == R11 will be used by the linker for synthesized instructions.
-TEXT udiv(SB),NOSPLIT,$-4
+TEXT runtime·udiv(SB),NOSPLIT,$-4
 	MOVBU	runtime·hardDiv(SB), Ra
 	CMP	$0, Ra
 	BNE	udiv_hardware
@@ -241,7 +241,7 @@ TEXT _divu(SB), NOSPLIT, $16-0
 	MOVW	Rn, Rr			/* numerator */
 	MOVW	g_m(g), Rq
 	MOVW	m_divmod(Rq), Rq	/* denominator */
-	BL  	udiv(SB)
+	BL  	runtime·udiv(SB)
 	MOVW	Rq, RTMP
 	MOVW	4(R13), Rq
 	MOVW	8(R13), Rr
@@ -259,7 +259,7 @@ TEXT _modu(SB), NOSPLIT, $16-0
 	MOVW	Rn, Rr			/* numerator */
 	MOVW	g_m(g), Rq
 	MOVW	m_divmod(Rq), Rq	/* denominator */
-	BL  	udiv(SB)
+	BL  	runtime·udiv(SB)
 	MOVW	Rr, RTMP
 	MOVW	4(R13), Rq
 	MOVW	8(R13), Rr
@@ -283,7 +283,7 @@ TEXT _div(SB),NOSPLIT,$16-0
 	BGE 	d2
 	RSB 	$0, Rq, Rq
 d0:
-	BL  	udiv(SB)  		/* none/both neg */
+	BL  	runtime·udiv(SB)  	/* none/both neg */
 	MOVW	Rq, RTMP
 	B	out1
 d1:
@@ -291,7 +291,7 @@ d1:
 	BGE 	d0
 	RSB 	$0, Rq, Rq
 d2:
-	BL  	udiv(SB)  		/* one neg */
+	BL  	runtime·udiv(SB)  	/* one neg */
 	RSB	$0, Rq, RTMP
 out1:
 	MOVW	4(R13), Rq
@@ -314,11 +314,11 @@ TEXT _mod(SB),NOSPLIT,$16-0
 	CMP 	$0, Rr
 	BGE 	m1
 	RSB 	$0, Rr, Rr
-	BL  	udiv(SB)  		/* neg numerator */
+	BL  	runtime·udiv(SB)  	/* neg numerator */
 	RSB 	$0, Rr, RTMP
 	B   	out
 m1:
-	BL  	udiv(SB)  		/* pos numerator */
+	BL  	runtime·udiv(SB)  	/* pos numerator */
 	MOVW	Rr, RTMP
 out:
 	MOVW	4(R13), Rq