cmd/compile: delete ZeroAuto

ZeroAuto was used with the ambiguously live logic. The
ambiguously live logic is removed as we switched to stack
objects. It is now never called. Remove.

Change-Id: If4cdd7fed5297f8ab591cc392a76c80f57820856
Reviewed-on: https://go-review.googlesource.com/c/go/+/203538
Run-TryBot: Cherry Zhang <cherryyz@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

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

@@ -17,7 +17,6 @@ func Init(arch *gc.Arch) {
 	arch.MAXWIDTH = 1 << 50
 
 	arch.ZeroRange = zerorange
-	arch.ZeroAuto = zeroAuto
 	arch.Ginsnop = ginsnop
 	arch.Ginsnopdefer = ginsnop
 

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

@@ -121,26 +121,6 @@ func zerorange(pp *gc.Progs, p *obj.Prog, off, cnt int64, state *uint32) *obj.Pr
 	return p
 }
 
-func zeroAuto(pp *gc.Progs, n *gc.Node) {
-	// Note: this code must not clobber any registers.
-	op := x86.AMOVQ
-	if gc.Widthptr == 4 {
-		op = x86.AMOVL
-	}
-	sym := n.Sym.Linksym()
-	size := n.Type.Size()
-	for i := int64(0); i < size; i += int64(gc.Widthptr) {
-		p := pp.Prog(op)
-		p.From.Type = obj.TYPE_CONST
-		p.From.Offset = 0
-		p.To.Type = obj.TYPE_MEM
-		p.To.Name = obj.NAME_AUTO
-		p.To.Reg = x86.REG_SP
-		p.To.Offset = n.Xoffset + i
-		p.To.Sym = sym
-	}
-}
-
 func ginsnop(pp *gc.Progs) *obj.Prog {
 	// This is a hardware nop (1-byte 0x90) instruction,
 	// even though we describe it as an explicit XCHGL here.

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

@@ -17,7 +17,6 @@ func Init(arch *gc.Arch) {
 	arch.MAXWIDTH = (1 << 32) - 1
 	arch.SoftFloat = objabi.GOARM == 5
 	arch.ZeroRange = zerorange
-	arch.ZeroAuto = zeroAuto
 	arch.Ginsnop = ginsnop
 	arch.Ginsnopdefer = ginsnop
 

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

@@ -47,27 +47,6 @@ func zerorange(pp *gc.Progs, p *obj.Prog, off, cnt int64, r0 *uint32) *obj.Prog
 	return p
 }
 
-func zeroAuto(pp *gc.Progs, n *gc.Node) {
-	// Note: this code must not clobber any registers.
-	sym := n.Sym.Linksym()
-	size := n.Type.Size()
-	p := pp.Prog(arm.AMOVW)
-	p.From.Type = obj.TYPE_CONST
-	p.From.Offset = 0
-	p.To.Type = obj.TYPE_REG
-	p.To.Reg = arm.REGTMP
-	for i := int64(0); i < size; i += 4 {
-		p := pp.Prog(arm.AMOVW)
-		p.From.Type = obj.TYPE_REG
-		p.From.Reg = arm.REGTMP
-		p.To.Type = obj.TYPE_MEM
-		p.To.Name = obj.NAME_AUTO
-		p.To.Reg = arm.REGSP
-		p.To.Offset = n.Xoffset + i
-		p.To.Sym = sym
-	}
-}
-
 func ginsnop(pp *gc.Progs) *obj.Prog {
 	p := pp.Prog(arm.AAND)
 	p.From.Type = obj.TYPE_REG

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

@@ -17,7 +17,6 @@ func Init(arch *gc.Arch) {
 
 	arch.PadFrame = padframe
 	arch.ZeroRange = zerorange
-	arch.ZeroAuto = zeroAuto
 	arch.Ginsnop = ginsnop
 	arch.Ginsnopdefer = ginsnop
 

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

@@ -63,22 +63,6 @@ func zerorange(pp *gc.Progs, p *obj.Prog, off, cnt int64, _ *uint32) *obj.Prog {
 	return p
 }
 
-func zeroAuto(pp *gc.Progs, n *gc.Node) {
-	// Note: this code must not clobber any registers.
-	sym := n.Sym.Linksym()
-	size := n.Type.Size()
-	for i := int64(0); i < size; i += 8 {
-		p := pp.Prog(arm64.AMOVD)
-		p.From.Type = obj.TYPE_REG
-		p.From.Reg = arm64.REGZERO
-		p.To.Type = obj.TYPE_MEM
-		p.To.Name = obj.NAME_AUTO
-		p.To.Reg = arm64.REGSP
-		p.To.Offset = n.Xoffset + i
-		p.To.Sym = sym
-	}
-}
-
 func ginsnop(pp *gc.Progs) *obj.Prog {
 	p := pp.Prog(arm64.AHINT)
 	p.From.Type = obj.TYPE_CONST

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

@@ -270,11 +270,6 @@ type Arch struct {
 	// SSAGenBlock emits end-of-block Progs. SSAGenValue should be called
 	// for all values in the block before SSAGenBlock.
 	SSAGenBlock func(s *SSAGenState, b, next *ssa.Block)
-
-	// ZeroAuto emits code to zero the given auto stack variable.
-	// ZeroAuto must not use any non-temporary registers.
-	// ZeroAuto will only be called for variables which contain a pointer.
-	ZeroAuto func(*Progs, *Node)
 }
 
 var thearch Arch

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

@@ -20,7 +20,6 @@ func Init(arch *gc.Arch) {
 	arch.MAXWIDTH = (1 << 31) - 1
 	arch.SoftFloat = (objabi.GOMIPS == "softfloat")
 	arch.ZeroRange = zerorange
-	arch.ZeroAuto = zeroAuto
 	arch.Ginsnop = ginsnop
 	arch.Ginsnopdefer = ginsnop
 	arch.SSAMarkMoves = func(s *gc.SSAGenState, b *ssa.Block) {}

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

@@ -43,22 +43,6 @@ func zerorange(pp *gc.Progs, p *obj.Prog, off, cnt int64, _ *uint32) *obj.Prog {
 	return p
 }
 
-func zeroAuto(pp *gc.Progs, n *gc.Node) {
-	// Note: this code must not clobber any registers.
-	sym := n.Sym.Linksym()
-	size := n.Type.Size()
-	for i := int64(0); i < size; i += 4 {
-		p := pp.Prog(mips.AMOVW)
-		p.From.Type = obj.TYPE_REG
-		p.From.Reg = mips.REGZERO
-		p.To.Type = obj.TYPE_MEM
-		p.To.Name = obj.NAME_AUTO
-		p.To.Reg = mips.REGSP
-		p.To.Offset = n.Xoffset + i
-		p.To.Sym = sym
-	}
-}
-
 func ginsnop(pp *gc.Progs) *obj.Prog {
 	p := pp.Prog(mips.ANOR)
 	p.From.Type = obj.TYPE_REG

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

@@ -20,7 +20,6 @@ func Init(arch *gc.Arch) {
 	arch.MAXWIDTH = 1 << 50
 	arch.SoftFloat = objabi.GOMIPS64 == "softfloat"
 	arch.ZeroRange = zerorange
-	arch.ZeroAuto = zeroAuto
 	arch.Ginsnop = ginsnop
 	arch.Ginsnopdefer = ginsnop
 

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

@@ -47,22 +47,6 @@ func zerorange(pp *gc.Progs, p *obj.Prog, off, cnt int64, _ *uint32) *obj.Prog {
 	return p
 }
 
-func zeroAuto(pp *gc.Progs, n *gc.Node) {
-	// Note: this code must not clobber any registers.
-	sym := n.Sym.Linksym()
-	size := n.Type.Size()
-	for i := int64(0); i < size; i += 8 {
-		p := pp.Prog(mips.AMOVV)
-		p.From.Type = obj.TYPE_REG
-		p.From.Reg = mips.REGZERO
-		p.To.Type = obj.TYPE_MEM
-		p.To.Name = obj.NAME_AUTO
-		p.To.Reg = mips.REGSP
-		p.To.Offset = n.Xoffset + i
-		p.To.Sym = sym
-	}
-}
-
 func ginsnop(pp *gc.Progs) *obj.Prog {
 	p := pp.Prog(mips.ANOR)
 	p.From.Type = obj.TYPE_REG

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

@@ -19,7 +19,6 @@ func Init(arch *gc.Arch) {
 	arch.MAXWIDTH = 1 << 60
 
 	arch.ZeroRange = zerorange
-	arch.ZeroAuto = zeroAuto
 	arch.Ginsnop = ginsnop
 	arch.Ginsnopdefer = ginsnopdefer
 

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

@@ -42,22 +42,6 @@ func zerorange(pp *gc.Progs, p *obj.Prog, off, cnt int64, _ *uint32) *obj.Prog {
 	return p
 }
 
-func zeroAuto(pp *gc.Progs, n *gc.Node) {
-	// Note: this code must not clobber any registers.
-	sym := n.Sym.Linksym()
-	size := n.Type.Size()
-	for i := int64(0); i < size; i += 8 {
-		p := pp.Prog(ppc64.AMOVD)
-		p.From.Type = obj.TYPE_REG
-		p.From.Reg = ppc64.REGZERO
-		p.To.Type = obj.TYPE_MEM
-		p.To.Name = obj.NAME_AUTO
-		p.To.Reg = ppc64.REGSP
-		p.To.Offset = n.Xoffset + i
-		p.To.Sym = sym
-	}
-}
-
 func ginsnop(pp *gc.Progs) *obj.Prog {
 	p := pp.Prog(ppc64.AOR)
 	p.From.Type = obj.TYPE_REG

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

@@ -15,7 +15,6 @@ func Init(arch *gc.Arch) {
 	arch.MAXWIDTH = 1 << 50
 
 	arch.ZeroRange = zerorange
-	arch.ZeroAuto = zeroAuto
 	arch.Ginsnop = ginsnop
 	arch.Ginsnopdefer = ginsnop
 

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

@@ -83,23 +83,6 @@ func zerorange(pp *gc.Progs, p *obj.Prog, off, cnt int64, _ *uint32) *obj.Prog {
 	return p
 }
 
-func zeroAuto(pp *gc.Progs, n *gc.Node) {
-	// Note: this code must not clobber any registers or the
-	// condition code.
-	sym := n.Sym.Linksym()
-	size := n.Type.Size()
-	for i := int64(0); i < size; i += int64(gc.Widthptr) {
-		p := pp.Prog(s390x.AMOVD)
-		p.From.Type = obj.TYPE_CONST
-		p.From.Offset = 0
-		p.To.Type = obj.TYPE_MEM
-		p.To.Name = obj.NAME_AUTO
-		p.To.Reg = s390x.REGSP
-		p.To.Offset = n.Xoffset + i
-		p.To.Sym = sym
-	}
-}
-
 func ginsnop(pp *gc.Progs) *obj.Prog {
 	return pp.Prog(s390x.ANOPH)
 }

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

@@ -19,7 +19,6 @@ func Init(arch *gc.Arch) {
 	arch.MAXWIDTH = 1 << 50
 
 	arch.ZeroRange = zeroRange
-	arch.ZeroAuto = zeroAuto
 	arch.Ginsnop = ginsnop
 	arch.Ginsnopdefer = ginsnop
 
@@ -45,21 +44,6 @@ func zeroRange(pp *gc.Progs, p *obj.Prog, off, cnt int64, state *uint32) *obj.Pr
 	return p
 }
 
-func zeroAuto(pp *gc.Progs, n *gc.Node) {
-	sym := n.Sym.Linksym()
-	size := n.Type.Size()
-	for i := int64(0); i < size; i += 8 {
-		p := pp.Prog(wasm.AGet)
-		p.From = obj.Addr{Type: obj.TYPE_REG, Reg: wasm.REG_SP}
-
-		p = pp.Prog(wasm.AI64Const)
-		p.From = obj.Addr{Type: obj.TYPE_CONST, Offset: 0}
-
-		p = pp.Prog(wasm.AI64Store)
-		p.To = obj.Addr{Type: obj.TYPE_MEM, Name: obj.NAME_AUTO, Offset: n.Xoffset + i, Sym: sym}
-	}
-}
-
 func ginsnop(pp *gc.Progs) *obj.Prog {
 	return pp.Prog(wasm.ANop)
 }

src/cmd/compile/internal/x86/galign.go

@@ -30,7 +30,6 @@ func Init(arch *gc.Arch) {
 	arch.MAXWIDTH = (1 << 32) - 1
 
 	arch.ZeroRange = zerorange
-	arch.ZeroAuto = zeroAuto
 	arch.Ginsnop = ginsnop
 	arch.Ginsnopdefer = ginsnop
 

src/cmd/compile/internal/x86/ggen.go

@@ -37,22 +37,6 @@ func zerorange(pp *gc.Progs, p *obj.Prog, off, cnt int64, ax *uint32) *obj.Prog
 	return p
 }
 
-func zeroAuto(pp *gc.Progs, n *gc.Node) {
-	// Note: this code must not clobber any registers.
-	sym := n.Sym.Linksym()
-	size := n.Type.Size()
-	for i := int64(0); i < size; i += 4 {
-		p := pp.Prog(x86.AMOVL)
-		p.From.Type = obj.TYPE_CONST
-		p.From.Offset = 0
-		p.To.Type = obj.TYPE_MEM
-		p.To.Name = obj.NAME_AUTO
-		p.To.Reg = x86.REG_SP
-		p.To.Offset = n.Xoffset + i
-		p.To.Sym = sym
-	}
-}
-
 func ginsnop(pp *gc.Progs) *obj.Prog {
 	// See comment in ../amd64/ggen.go.
 	p := pp.Prog(x86.AXCHGL)