cmd/compile: remove traces of old register allocator

Only added lines are moving amd64 and x86's ginsnop functions from
gsubr.go to ggen.go to match other architectures, so all of the
gsubr.go files can go away.

Change-Id: Ib2292460c155ae6d9dcf5c9801f178031d8eea7a
Reviewed-on: https://go-review.googlesource.com/29240
Run-TryBot: Matthew Dempsky <mdempsky@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Dave Cheney <dave@cheney.net>

src/cmd/compile/internal/amd64/galign.go

@@ -18,13 +18,6 @@ func betypeinit() {
 	if obj.GOARCH == "amd64p32" {
 		leaptr = x86.ALEAL
 	}
-	if gc.Ctxt.Flag_dynlink || obj.GOOS == "nacl" {
-		resvd = append(resvd, x86.REG_R15)
-	}
-	if gc.Ctxt.Framepointer_enabled || obj.GOOS == "nacl" {
-		resvd = append(resvd, x86.REG_BP)
-	}
-	gc.Thearch.ReservedRegs = resvd
 }
 
 func Main() {
@@ -34,13 +27,6 @@ func Main() {
 	}
 	gc.Thearch.REGSP = x86.REGSP
 	gc.Thearch.REGCTXT = x86.REGCTXT
-	gc.Thearch.REGCALLX = x86.REG_BX
-	gc.Thearch.REGCALLX2 = x86.REG_AX
-	gc.Thearch.REGRETURN = x86.REG_AX
-	gc.Thearch.REGMIN = x86.REG_AX
-	gc.Thearch.REGMAX = x86.REG_R15
-	gc.Thearch.FREGMIN = x86.REG_X0
-	gc.Thearch.FREGMAX = x86.REG_X15
 	gc.Thearch.MAXWIDTH = 1 << 50
 
 	gc.Thearch.Betypeinit = betypeinit

src/cmd/compile/internal/amd64/ggen.go

@@ -165,3 +165,14 @@ func zerorange(p *obj.Prog, frame int64, lo int64, hi int64, ax *uint32, x0 *uin
 
 	return p
 }
+
+func ginsnop() {
+	// This is actually not the x86 NOP anymore,
+	// but at the point where it gets used, AX is dead
+	// so it's okay if we lose the high bits.
+	p := gc.Prog(x86.AXCHGL)
+	p.From.Type = obj.TYPE_REG
+	p.From.Reg = x86.REG_AX
+	p.To.Type = obj.TYPE_REG
+	p.To.Reg = x86.REG_AX
+}

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

@@ -17,15 +17,7 @@ func Main() {
 	gc.Thearch.LinkArch = &arm.Linkarm
 	gc.Thearch.REGSP = arm.REGSP
 	gc.Thearch.REGCTXT = arm.REGCTXT
-	gc.Thearch.REGCALLX = arm.REG_R1
-	gc.Thearch.REGCALLX2 = arm.REG_R2
-	gc.Thearch.REGRETURN = arm.REG_R0
-	gc.Thearch.REGMIN = arm.REG_R0
-	gc.Thearch.REGMAX = arm.REGEXT
-	gc.Thearch.FREGMIN = arm.REG_F0
-	gc.Thearch.FREGMAX = arm.FREGEXT
 	gc.Thearch.MAXWIDTH = (1 << 32) - 1
-	gc.Thearch.ReservedRegs = resvd
 
 	gc.Thearch.Betypeinit = betypeinit
 	gc.Thearch.Defframe = defframe

src/cmd/compile/internal/arm64/galign.go

@@ -17,16 +17,7 @@ func Main() {
 	gc.Thearch.LinkArch = &arm64.Linkarm64
 	gc.Thearch.REGSP = arm64.REGSP
 	gc.Thearch.REGCTXT = arm64.REGCTXT
-	gc.Thearch.REGCALLX = arm64.REGRT1
-	gc.Thearch.REGCALLX2 = arm64.REGRT2
-	gc.Thearch.REGRETURN = arm64.REG_R0
-	gc.Thearch.REGMIN = arm64.REG_R0
-	gc.Thearch.REGMAX = arm64.REG_R31
-	gc.Thearch.REGZERO = arm64.REGZERO
-	gc.Thearch.FREGMIN = arm64.REG_F0
-	gc.Thearch.FREGMAX = arm64.REG_F31
 	gc.Thearch.MAXWIDTH = 1 << 50
-	gc.Thearch.ReservedRegs = resvd
 
 	gc.Thearch.Betypeinit = betypeinit
 	gc.Thearch.Defframe = defframe

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

@@ -355,18 +355,9 @@ const (
 type Arch struct {
 	LinkArch *obj.LinkArch
 
-	REGSP        int
-	REGCTXT      int
-	REGCALLX     int // BX
-	REGCALLX2    int // AX
-	REGRETURN    int // AX
-	REGMIN       int
-	REGMAX       int
-	REGZERO      int // architectural zero register, if available
-	FREGMIN      int
-	FREGMAX      int
-	MAXWIDTH     int64
-	ReservedRegs []int
+	REGSP    int
+	REGCTXT  int
+	MAXWIDTH int64
 
 	Betypeinit func()
 	Defframe   func(*obj.Prog)

src/cmd/compile/internal/mips64/galign.go

@@ -21,15 +21,7 @@ func Main() {
 	}
 	gc.Thearch.REGSP = mips.REGSP
 	gc.Thearch.REGCTXT = mips.REGCTXT
-	gc.Thearch.REGCALLX = mips.REG_R1
-	gc.Thearch.REGCALLX2 = mips.REG_R2
-	gc.Thearch.REGRETURN = mips.REGRET
-	gc.Thearch.REGMIN = mips.REG_R0
-	gc.Thearch.REGMAX = mips.REG_R31
-	gc.Thearch.FREGMIN = mips.REG_F0
-	gc.Thearch.FREGMAX = mips.REG_F31
 	gc.Thearch.MAXWIDTH = 1 << 50
-	gc.Thearch.ReservedRegs = resvd
 
 	gc.Thearch.Betypeinit = betypeinit
 	gc.Thearch.Defframe = defframe

src/cmd/compile/internal/ppc64/galign.go

@@ -11,10 +11,6 @@ import (
 )
 
 func betypeinit() {
-	if gc.Ctxt.Flag_shared {
-		gc.Thearch.ReservedRegs = append(gc.Thearch.ReservedRegs, ppc64.REG_R2)
-		gc.Thearch.ReservedRegs = append(gc.Thearch.ReservedRegs, ppc64.REG_R12)
-	}
 }
 
 func Main() {
@@ -24,15 +20,7 @@ func Main() {
 	}
 	gc.Thearch.REGSP = ppc64.REGSP
 	gc.Thearch.REGCTXT = ppc64.REGCTXT
-	gc.Thearch.REGCALLX = ppc64.REG_R3
-	gc.Thearch.REGCALLX2 = ppc64.REG_R4
-	gc.Thearch.REGRETURN = ppc64.REG_R3
-	gc.Thearch.REGMIN = ppc64.REG_R0
-	gc.Thearch.REGMAX = ppc64.REG_R31
-	gc.Thearch.FREGMIN = ppc64.REG_F0
-	gc.Thearch.FREGMAX = ppc64.REG_F31
 	gc.Thearch.MAXWIDTH = 1 << 50
-	gc.Thearch.ReservedRegs = resvd
 
 	gc.Thearch.Betypeinit = betypeinit
 	gc.Thearch.Defframe = defframe

src/cmd/compile/internal/s390x/galign.go

@@ -16,15 +16,7 @@ func Main() {
 	gc.Thearch.LinkArch = &s390x.Links390x
 	gc.Thearch.REGSP = s390x.REGSP
 	gc.Thearch.REGCTXT = s390x.REGCTXT
-	gc.Thearch.REGCALLX = s390x.REG_R3
-	gc.Thearch.REGCALLX2 = s390x.REG_R4
-	gc.Thearch.REGRETURN = s390x.REG_R3
-	gc.Thearch.REGMIN = s390x.REG_R0
-	gc.Thearch.REGMAX = s390x.REG_R15
-	gc.Thearch.FREGMIN = s390x.REG_F0
-	gc.Thearch.FREGMAX = s390x.REG_F15
 	gc.Thearch.MAXWIDTH = 1 << 50
-	gc.Thearch.ReservedRegs = resvd
 
 	gc.Thearch.Betypeinit = betypeinit
 	gc.Thearch.Defframe = defframe