Adding upstream version 1.22.1.upstream/1.22.1

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 1123 insertions, 0 deletions

diff --git a/src/cmd/internal/obj/arm64/obj7.go b/src/cmd/internal/obj/arm64/obj7.go
new file mode 100644
index 0000000..0ab5939
--- /dev/null
+++ b/src/cmd/internal/obj/arm64/obj7.go
@@ -0,0 +1,1123 @@
+// cmd/7l/noop.c, cmd/7l/obj.c, cmd/ld/pass.c from Vita Nuova.
+// https://bitbucket.org/plan9-from-bell-labs/9-cc/src/master/
+//
+// 	Copyright © 1994-1999 Lucent Technologies Inc. All rights reserved.
+// 	Portions Copyright © 1995-1997 C H Forsyth (forsyth@terzarima.net)
+// 	Portions Copyright © 1997-1999 Vita Nuova Limited
+// 	Portions Copyright © 2000-2007 Vita Nuova Holdings Limited (www.vitanuova.com)
+// 	Portions Copyright © 2004,2006 Bruce Ellis
+// 	Portions Copyright © 2005-2007 C H Forsyth (forsyth@terzarima.net)
+// 	Revisions Copyright © 2000-2007 Lucent Technologies Inc. and others
+// 	Portions Copyright © 2009 The Go Authors. All rights reserved.
+//
+// Permission is hereby granted, free of charge, to any person obtaining a copy
+// of this software and associated documentation files (the "Software"), to deal
+// in the Software without restriction, including without limitation the rights
+// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+// copies of the Software, and to permit persons to whom the Software is
+// furnished to do so, subject to the following conditions:
+//
+// The above copyright notice and this permission notice shall be included in
+// all copies or substantial portions of the Software.
+//
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL THE
+// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+// THE SOFTWARE.
+
+package arm64
+
+import (
+	"cmd/internal/obj"
+	"cmd/internal/objabi"
+	"cmd/internal/src"
+	"cmd/internal/sys"
+	"internal/abi"
+	"internal/buildcfg"
+	"log"
+	"math"
+)
+
+// zrReplace is the set of instructions for which $0 in the From operand
+// should be replaced with REGZERO.
+var zrReplace = map[obj.As]bool{
+	AMOVD:  true,
+	AMOVW:  true,
+	AMOVWU: true,
+	AMOVH:  true,
+	AMOVHU: true,
+	AMOVB:  true,
+	AMOVBU: true,
+	ASBC:   true,
+	ASBCW:  true,
+	ASBCS:  true,
+	ASBCSW: true,
+	AADC:   true,
+	AADCW:  true,
+	AADCS:  true,
+	AADCSW: true,
+	AFMOVD: true,
+	AFMOVS: true,
+	AMSR:   true,
+}
+
+func (c *ctxt7) stacksplit(p *obj.Prog, framesize int32) *obj.Prog {
+	if c.ctxt.Flag_maymorestack != "" {
+		p = c.cursym.Func().SpillRegisterArgs(p, c.newprog)
+
+		// Save LR and make room for FP, REGCTXT. Leave room
+		// for caller's saved FP.
+		const frameSize = 32
+		p = obj.Appendp(p, c.newprog)
+		p.As = AMOVD
+		p.From.Type = obj.TYPE_REG
+		p.From.Reg = REGLINK
+		p.To.Type = obj.TYPE_MEM
+		p.Scond = C_XPRE
+		p.To.Offset = -frameSize
+		p.To.Reg = REGSP
+		p.Spadj = frameSize
+
+		// Save FP.
+		p = obj.Appendp(p, c.newprog)
+		p.As = AMOVD
+		p.From.Type = obj.TYPE_REG
+		p.From.Reg = REGFP
+		p.To.Type = obj.TYPE_MEM
+		p.To.Reg = REGSP
+		p.To.Offset = -8
+
+		p = obj.Appendp(p, c.newprog)
+		p.As = ASUB
+		p.From.Type = obj.TYPE_CONST
+		p.From.Offset = 8
+		p.Reg = REGSP
+		p.To.Type = obj.TYPE_REG
+		p.To.Reg = REGFP
+
+		// Save REGCTXT (for simplicity we do this whether or
+		// not we need it.)
+		p = obj.Appendp(p, c.newprog)
+		p.As = AMOVD
+		p.From.Type = obj.TYPE_REG
+		p.From.Reg = REGCTXT
+		p.To.Type = obj.TYPE_MEM
+		p.To.Reg = REGSP
+		p.To.Offset = 8
+
+		// BL maymorestack
+		p = obj.Appendp(p, c.newprog)
+		p.As = ABL
+		p.To.Type = obj.TYPE_BRANCH
+		// See ../x86/obj6.go
+		p.To.Sym = c.ctxt.LookupABI(c.ctxt.Flag_maymorestack, c.cursym.ABI())
+
+		// Restore REGCTXT.
+		p = obj.Appendp(p, c.newprog)
+		p.As = AMOVD
+		p.From.Type = obj.TYPE_MEM
+		p.From.Reg = REGSP
+		p.From.Offset = 8
+		p.To.Type = obj.TYPE_REG
+		p.To.Reg = REGCTXT
+
+		// Restore FP.
+		p = obj.Appendp(p, c.newprog)
+		p.As = AMOVD
+		p.From.Type = obj.TYPE_MEM
+		p.From.Reg = REGSP
+		p.From.Offset = -8
+		p.To.Type = obj.TYPE_REG
+		p.To.Reg = REGFP
+
+		// Restore LR and SP.
+		p = obj.Appendp(p, c.newprog)
+		p.As = AMOVD
+		p.From.Type = obj.TYPE_MEM
+		p.Scond = C_XPOST
+		p.From.Offset = frameSize
+		p.From.Reg = REGSP
+		p.To.Type = obj.TYPE_REG
+		p.To.Reg = REGLINK
+		p.Spadj = -frameSize
+
+		p = c.cursym.Func().UnspillRegisterArgs(p, c.newprog)
+	}
+
+	// Jump back to here after morestack returns.
+	startPred := p
+
+	// MOV	g_stackguard(g), RT1
+	p = obj.Appendp(p, c.newprog)
+
+	p.As = AMOVD
+	p.From.Type = obj.TYPE_MEM
+	p.From.Reg = REGG
+	p.From.Offset = 2 * int64(c.ctxt.Arch.PtrSize) // G.stackguard0
+	if c.cursym.CFunc() {
+		p.From.Offset = 3 * int64(c.ctxt.Arch.PtrSize) // G.stackguard1
+	}
+	p.To.Type = obj.TYPE_REG
+	p.To.Reg = REGRT1
+
+	// Mark the stack bound check and morestack call async nonpreemptible.
+	// If we get preempted here, when resumed the preemption request is
+	// cleared, but we'll still call morestack, which will double the stack
+	// unnecessarily. See issue #35470.
+	p = c.ctxt.StartUnsafePoint(p, c.newprog)
+
+	q := (*obj.Prog)(nil)
+	if framesize <= abi.StackSmall {
+		// small stack: SP < stackguard
+		//	CMP	stackguard, SP
+
+		p = obj.Appendp(p, c.newprog)
+		p.As = ACMP
+		p.From.Type = obj.TYPE_REG
+		p.From.Reg = REGRT1
+		p.Reg = REGSP
+	} else if framesize <= abi.StackBig {
+		// large stack: SP-framesize < stackguard-StackSmall
+		//	SUB	$(framesize-StackSmall), SP, RT2
+		//	CMP	stackguard, RT2
+		p = obj.Appendp(p, c.newprog)
+
+		p.As = ASUB
+		p.From.Type = obj.TYPE_CONST
+		p.From.Offset = int64(framesize) - abi.StackSmall
+		p.Reg = REGSP
+		p.To.Type = obj.TYPE_REG
+		p.To.Reg = REGRT2
+
+		p = obj.Appendp(p, c.newprog)
+		p.As = ACMP
+		p.From.Type = obj.TYPE_REG
+		p.From.Reg = REGRT1
+		p.Reg = REGRT2
+	} else {
+		// Such a large stack we need to protect against underflow.
+		// The runtime guarantees SP > objabi.StackBig, but
+		// framesize is large enough that SP-framesize may
+		// underflow, causing a direct comparison with the
+		// stack guard to incorrectly succeed. We explicitly
+		// guard against underflow.
+		//
+		//	SUBS	$(framesize-StackSmall), SP, RT2
+		//	// On underflow, jump to morestack
+		//	BLO	label_of_call_to_morestack
+		//	CMP	stackguard, RT2
+
+		p = obj.Appendp(p, c.newprog)
+		p.As = ASUBS
+		p.From.Type = obj.TYPE_CONST
+		p.From.Offset = int64(framesize) - abi.StackSmall
+		p.Reg = REGSP
+		p.To.Type = obj.TYPE_REG
+		p.To.Reg = REGRT2
+
+		p = obj.Appendp(p, c.newprog)
+		q = p
+		p.As = ABLO
+		p.To.Type = obj.TYPE_BRANCH
+
+		p = obj.Appendp(p, c.newprog)
+		p.As = ACMP
+		p.From.Type = obj.TYPE_REG
+		p.From.Reg = REGRT1
+		p.Reg = REGRT2
+	}
+
+	// BLS	do-morestack
+	bls := obj.Appendp(p, c.newprog)
+	bls.As = ABLS
+	bls.To.Type = obj.TYPE_BRANCH
+
+	end := c.ctxt.EndUnsafePoint(bls, c.newprog, -1)
+
+	var last *obj.Prog
+	for last = c.cursym.Func().Text; last.Link != nil; last = last.Link {
+	}
+
+	// Now we are at the end of the function, but logically
+	// we are still in function prologue. We need to fix the
+	// SP data and PCDATA.
+	spfix := obj.Appendp(last, c.newprog)
+	spfix.As = obj.ANOP
+	spfix.Spadj = -framesize
+
+	pcdata := c.ctxt.EmitEntryStackMap(c.cursym, spfix, c.newprog)
+	pcdata = c.ctxt.StartUnsafePoint(pcdata, c.newprog)
+
+	if q != nil {
+		q.To.SetTarget(pcdata)
+	}
+	bls.To.SetTarget(pcdata)
+
+	spill := c.cursym.Func().SpillRegisterArgs(pcdata, c.newprog)
+
+	// MOV	LR, R3
+	movlr := obj.Appendp(spill, c.newprog)
+	movlr.As = AMOVD
+	movlr.From.Type = obj.TYPE_REG
+	movlr.From.Reg = REGLINK
+	movlr.To.Type = obj.TYPE_REG
+	movlr.To.Reg = REG_R3
+
+	debug := movlr
+	if false {
+		debug = obj.Appendp(debug, c.newprog)
+		debug.As = AMOVD
+		debug.From.Type = obj.TYPE_CONST
+		debug.From.Offset = int64(framesize)
+		debug.To.Type = obj.TYPE_REG
+		debug.To.Reg = REGTMP
+	}
+
+	// BL	runtime.morestack(SB)
+	call := obj.Appendp(debug, c.newprog)
+	call.As = ABL
+	call.To.Type = obj.TYPE_BRANCH
+	morestack := "runtime.morestack"
+	switch {
+	case c.cursym.CFunc():
+		morestack = "runtime.morestackc"
+	case !c.cursym.Func().Text.From.Sym.NeedCtxt():
+		morestack = "runtime.morestack_noctxt"
+	}
+	call.To.Sym = c.ctxt.Lookup(morestack)
+
+	// The instructions which unspill regs should be preemptible.
+	pcdata = c.ctxt.EndUnsafePoint(call, c.newprog, -1)
+	unspill := c.cursym.Func().UnspillRegisterArgs(pcdata, c.newprog)
+
+	// B	start
+	jmp := obj.Appendp(unspill, c.newprog)
+	jmp.As = AB
+	jmp.To.Type = obj.TYPE_BRANCH
+	jmp.To.SetTarget(startPred.Link)
+	jmp.Spadj = +framesize
+
+	return end
+}
+
+func progedit(ctxt *obj.Link, p *obj.Prog, newprog obj.ProgAlloc) {
+	c := ctxt7{ctxt: ctxt, newprog: newprog}
+
+	p.From.Class = 0
+	p.To.Class = 0
+
+	// Previously we rewrote $0 to ZR, but we have now removed this change.
+	// In order to be compatible with some previous legal instruction formats,
+	// reserve the previous conversion for some specific instructions.
+	if p.From.Type == obj.TYPE_CONST && p.From.Offset == 0 && zrReplace[p.As] {
+		p.From.Type = obj.TYPE_REG
+		p.From.Reg = REGZERO
+	}
+
+	// Rewrite BR/BL to symbol as TYPE_BRANCH.
+	switch p.As {
+	case AB,
+		ABL,
+		obj.ARET,
+		obj.ADUFFZERO,
+		obj.ADUFFCOPY:
+		if p.To.Sym != nil {
+			p.To.Type = obj.TYPE_BRANCH
+		}
+		break
+	}
+
+	// Rewrite float and vector constants to values stored in memory.
+	switch p.As {
+	case AVMOVS:
+		if p.From.Type == obj.TYPE_CONST {
+			p.From.Type = obj.TYPE_MEM
+			p.From.Sym = c.ctxt.Int32Sym(p.From.Offset)
+			p.From.Name = obj.NAME_EXTERN
+			p.From.Offset = 0
+		}
+
+	case AVMOVD:
+		if p.From.Type == obj.TYPE_CONST {
+			p.From.Type = obj.TYPE_MEM
+			p.From.Sym = c.ctxt.Int64Sym(p.From.Offset)
+			p.From.Name = obj.NAME_EXTERN
+			p.From.Offset = 0
+		}
+
+	case AVMOVQ:
+		if p.From.Type == obj.TYPE_CONST {
+			p.From.Type = obj.TYPE_MEM
+			p.From.Sym = c.ctxt.Int128Sym(p.GetFrom3().Offset, p.From.Offset)
+			p.From.Name = obj.NAME_EXTERN
+			p.From.Offset = 0
+			p.RestArgs = nil
+		}
+
+	case AFMOVS:
+		if p.From.Type == obj.TYPE_FCONST {
+			f64 := p.From.Val.(float64)
+			f32 := float32(f64)
+			if c.chipfloat7(f64) > 0 {
+				break
+			}
+			if math.Float32bits(f32) == 0 {
+				p.From.Type = obj.TYPE_REG
+				p.From.Reg = REGZERO
+				break
+			}
+			p.From.Type = obj.TYPE_MEM
+			p.From.Sym = c.ctxt.Float32Sym(f32)
+			p.From.Name = obj.NAME_EXTERN
+			p.From.Offset = 0
+		}
+
+	case AFMOVD:
+		if p.From.Type == obj.TYPE_FCONST {
+			f64 := p.From.Val.(float64)
+			if c.chipfloat7(f64) > 0 {
+				break
+			}
+			if math.Float64bits(f64) == 0 {
+				p.From.Type = obj.TYPE_REG
+				p.From.Reg = REGZERO
+				break
+			}
+			p.From.Type = obj.TYPE_MEM
+			p.From.Sym = c.ctxt.Float64Sym(f64)
+			p.From.Name = obj.NAME_EXTERN
+			p.From.Offset = 0
+		}
+	}
+
+	if c.ctxt.Flag_dynlink {
+		c.rewriteToUseGot(p)
+	}
+}
+
+// Rewrite p, if necessary, to access global data via the global offset table.
+func (c *ctxt7) rewriteToUseGot(p *obj.Prog) {
+	if p.As == obj.ADUFFCOPY || p.As == obj.ADUFFZERO {
+		//     ADUFFxxx $offset
+		// becomes
+		//     MOVD runtime.duffxxx@GOT, REGTMP
+		//     ADD $offset, REGTMP
+		//     CALL REGTMP
+		var sym *obj.LSym
+		if p.As == obj.ADUFFZERO {
+			sym = c.ctxt.LookupABI("runtime.duffzero", obj.ABIInternal)
+		} else {
+			sym = c.ctxt.LookupABI("runtime.duffcopy", obj.ABIInternal)
+		}
+		offset := p.To.Offset
+		p.As = AMOVD
+		p.From.Type = obj.TYPE_MEM
+		p.From.Name = obj.NAME_GOTREF
+		p.From.Sym = sym
+		p.To.Type = obj.TYPE_REG
+		p.To.Reg = REGTMP
+		p.To.Name = obj.NAME_NONE
+		p.To.Offset = 0
+		p.To.Sym = nil
+		p1 := obj.Appendp(p, c.newprog)
+		p1.As = AADD
+		p1.From.Type = obj.TYPE_CONST
+		p1.From.Offset = offset
+		p1.To.Type = obj.TYPE_REG
+		p1.To.Reg = REGTMP
+		p2 := obj.Appendp(p1, c.newprog)
+		p2.As = obj.ACALL
+		p2.To.Type = obj.TYPE_REG
+		p2.To.Reg = REGTMP
+	}
+
+	// We only care about global data: NAME_EXTERN means a global
+	// symbol in the Go sense, and p.Sym.Local is true for a few
+	// internally defined symbols.
+	if p.From.Type == obj.TYPE_ADDR && p.From.Name == obj.NAME_EXTERN && !p.From.Sym.Local() {
+		// MOVD $sym, Rx becomes MOVD sym@GOT, Rx
+		// MOVD $sym+<off>, Rx becomes MOVD sym@GOT, Rx; ADD <off>, Rx
+		if p.As != AMOVD {
+			c.ctxt.Diag("do not know how to handle TYPE_ADDR in %v with -dynlink", p)
+		}
+		if p.To.Type != obj.TYPE_REG {
+			c.ctxt.Diag("do not know how to handle LEAQ-type insn to non-register in %v with -dynlink", p)
+		}
+		p.From.Type = obj.TYPE_MEM
+		p.From.Name = obj.NAME_GOTREF
+		if p.From.Offset != 0 {
+			q := obj.Appendp(p, c.newprog)
+			q.As = AADD
+			q.From.Type = obj.TYPE_CONST
+			q.From.Offset = p.From.Offset
+			q.To = p.To
+			p.From.Offset = 0
+		}
+	}
+	if p.GetFrom3() != nil && p.GetFrom3().Name == obj.NAME_EXTERN {
+		c.ctxt.Diag("don't know how to handle %v with -dynlink", p)
+	}
+	var source *obj.Addr
+	// MOVx sym, Ry becomes MOVD sym@GOT, REGTMP; MOVx (REGTMP), Ry
+	// MOVx Ry, sym becomes MOVD sym@GOT, REGTMP; MOVD Ry, (REGTMP)
+	// An addition may be inserted between the two MOVs if there is an offset.
+	if p.From.Name == obj.NAME_EXTERN && !p.From.Sym.Local() {
+		if p.To.Name == obj.NAME_EXTERN && !p.To.Sym.Local() {
+			c.ctxt.Diag("cannot handle NAME_EXTERN on both sides in %v with -dynlink", p)
+		}
+		source = &p.From
+	} else if p.To.Name == obj.NAME_EXTERN && !p.To.Sym.Local() {
+		source = &p.To
+	} else {
+		return
+	}
+	if p.As == obj.ATEXT || p.As == obj.AFUNCDATA || p.As == obj.ACALL || p.As == obj.ARET || p.As == obj.AJMP {
+		return
+	}
+	if source.Sym.Type == objabi.STLSBSS {
+		return
+	}
+	if source.Type != obj.TYPE_MEM {
+		c.ctxt.Diag("don't know how to handle %v with -dynlink", p)
+	}
+	p1 := obj.Appendp(p, c.newprog)
+	p2 := obj.Appendp(p1, c.newprog)
+	p1.As = AMOVD
+	p1.From.Type = obj.TYPE_MEM
+	p1.From.Sym = source.Sym
+	p1.From.Name = obj.NAME_GOTREF
+	p1.To.Type = obj.TYPE_REG
+	p1.To.Reg = REGTMP
+
+	p2.As = p.As
+	p2.From = p.From
+	p2.To = p.To
+	if p.From.Name == obj.NAME_EXTERN {
+		p2.From.Reg = REGTMP
+		p2.From.Name = obj.NAME_NONE
+		p2.From.Sym = nil
+	} else if p.To.Name == obj.NAME_EXTERN {
+		p2.To.Reg = REGTMP
+		p2.To.Name = obj.NAME_NONE
+		p2.To.Sym = nil
+	} else {
+		return
+	}
+	obj.Nopout(p)
+}
+
+func preprocess(ctxt *obj.Link, cursym *obj.LSym, newprog obj.ProgAlloc) {
+	if cursym.Func().Text == nil || cursym.Func().Text.Link == nil {
+		return
+	}
+
+	c := ctxt7{ctxt: ctxt, newprog: newprog, cursym: cursym}
+
+	p := c.cursym.Func().Text
+	textstksiz := p.To.Offset
+	if textstksiz == -8 {
+		// Historical way to mark NOFRAME.
+		p.From.Sym.Set(obj.AttrNoFrame, true)
+		textstksiz = 0
+	}
+	if textstksiz < 0 {
+		c.ctxt.Diag("negative frame size %d - did you mean NOFRAME?", textstksiz)
+	}
+	if p.From.Sym.NoFrame() {
+		if textstksiz != 0 {
+			c.ctxt.Diag("NOFRAME functions must have a frame size of 0, not %d", textstksiz)
+		}
+	}
+
+	c.cursym.Func().Args = p.To.Val.(int32)
+	c.cursym.Func().Locals = int32(textstksiz)
+
+	/*
+	 * find leaf subroutines
+	 */
+	for p := c.cursym.Func().Text; p != nil; p = p.Link {
+		switch p.As {
+		case obj.ATEXT:
+			p.Mark |= LEAF
+
+		case ABL,
+			obj.ADUFFZERO,
+			obj.ADUFFCOPY:
+			c.cursym.Func().Text.Mark &^= LEAF
+		}
+	}
+
+	var q *obj.Prog
+	var q1 *obj.Prog
+	var retjmp *obj.LSym
+	for p := c.cursym.Func().Text; p != nil; p = p.Link {
+		o := p.As
+		switch o {
+		case obj.ATEXT:
+			c.cursym.Func().Text = p
+			c.autosize = int32(textstksiz)
+
+			if p.Mark&LEAF != 0 && c.autosize == 0 {
+				// A leaf function with no locals has no frame.
+				p.From.Sym.Set(obj.AttrNoFrame, true)
+			}
+
+			if !p.From.Sym.NoFrame() {
+				// If there is a stack frame at all, it includes
+				// space to save the LR.
+				c.autosize += 8
+			}
+
+			if c.autosize != 0 {
+				extrasize := int32(0)
+				if c.autosize%16 == 8 {
+					// Allocate extra 8 bytes on the frame top to save FP
+					extrasize = 8
+				} else if c.autosize&(16-1) == 0 {
+					// Allocate extra 16 bytes to save FP for the old frame whose size is 8 mod 16
+					extrasize = 16
+				} else {
+					c.ctxt.Diag("%v: unaligned frame size %d - must be 16 aligned", p, c.autosize-8)
+				}
+				c.autosize += extrasize
+				c.cursym.Func().Locals += extrasize
+
+				// low 32 bits for autosize
+				// high 32 bits for extrasize
+				p.To.Offset = int64(c.autosize) | int64(extrasize)<<32
+			} else {
+				// NOFRAME
+				p.To.Offset = 0
+			}
+
+			if c.autosize == 0 && c.cursym.Func().Text.Mark&LEAF == 0 {
+				if c.ctxt.Debugvlog {
+					c.ctxt.Logf("save suppressed in: %s\n", c.cursym.Func().Text.From.Sym.Name)
+				}
+				c.cursym.Func().Text.Mark |= LEAF
+			}
+
+			if cursym.Func().Text.Mark&LEAF != 0 {
+				cursym.Set(obj.AttrLeaf, true)
+				if p.From.Sym.NoFrame() {
+					break
+				}
+			}
+
+			if p.Mark&LEAF != 0 && c.autosize < abi.StackSmall {
+				// A leaf function with a small stack can be marked
+				// NOSPLIT, avoiding a stack check.
+				p.From.Sym.Set(obj.AttrNoSplit, true)
+			}
+
+			if !p.From.Sym.NoSplit() {
+				p = c.stacksplit(p, c.autosize) // emit split check
+			}
+
+			var prologueEnd *obj.Prog
+
+			aoffset := c.autosize
+			if aoffset > 0xf0 {
+				// MOVD.W offset variant range is -0x100 to 0xf8, SP should be 16-byte aligned.
+				// so the maximum aoffset value is 0xf0.
+				aoffset = 0xf0
+			}
+
+			// Frame is non-empty. Make sure to save link register, even if
+			// it is a leaf function, so that traceback works.
+			q = p
+			if c.autosize > aoffset {
+				// Frame size is too large for a MOVD.W instruction. Store the frame pointer
+				// register and link register before decrementing SP, so if a signal comes
+				// during the execution of the function prologue, the traceback code will
+				// not see a half-updated stack frame.
+
+				// SUB $autosize, RSP, R20
+				q1 = obj.Appendp(q, c.newprog)
+				q1.Pos = p.Pos
+				q1.As = ASUB
+				q1.From.Type = obj.TYPE_CONST
+				q1.From.Offset = int64(c.autosize)
+				q1.Reg = REGSP
+				q1.To.Type = obj.TYPE_REG
+				q1.To.Reg = REG_R20
+
+				prologueEnd = q1
+
+				// STP (R29, R30), -8(R20)
+				q1 = obj.Appendp(q1, c.newprog)
+				q1.Pos = p.Pos
+				q1.As = ASTP
+				q1.From.Type = obj.TYPE_REGREG
+				q1.From.Reg = REGFP
+				q1.From.Offset = REGLINK
+				q1.To.Type = obj.TYPE_MEM
+				q1.To.Reg = REG_R20
+				q1.To.Offset = -8
+
+				// This is not async preemptible, as if we open a frame
+				// at the current SP, it will clobber the saved LR.
+				q1 = c.ctxt.StartUnsafePoint(q1, c.newprog)
+
+				// MOVD R20, RSP
+				q1 = obj.Appendp(q1, c.newprog)
+				q1.Pos = p.Pos
+				q1.As = AMOVD
+				q1.From.Type = obj.TYPE_REG
+				q1.From.Reg = REG_R20
+				q1.To.Type = obj.TYPE_REG
+				q1.To.Reg = REGSP
+				q1.Spadj = c.autosize
+
+				q1 = c.ctxt.EndUnsafePoint(q1, c.newprog, -1)
+
+				if buildcfg.GOOS == "ios" {
+					// iOS does not support SA_ONSTACK. We will run the signal handler
+					// on the G stack. If we write below SP, it may be clobbered by
+					// the signal handler. So we save FP and LR after decrementing SP.
+					// STP (R29, R30), -8(RSP)
+					q1 = obj.Appendp(q1, c.newprog)
+					q1.Pos = p.Pos
+					q1.As = ASTP
+					q1.From.Type = obj.TYPE_REGREG
+					q1.From.Reg = REGFP
+					q1.From.Offset = REGLINK
+					q1.To.Type = obj.TYPE_MEM
+					q1.To.Reg = REGSP
+					q1.To.Offset = -8
+				}
+			} else {
+				// small frame, update SP and save LR in a single MOVD.W instruction.
+				// So if a signal comes during the execution of the function prologue,
+				// the traceback code will not see a half-updated stack frame.
+				// Also, on Linux, in a cgo binary we may get a SIGSETXID signal
+				// early on before the signal stack is set, as glibc doesn't allow
+				// us to block SIGSETXID. So it is important that we don't write below
+				// the SP until the signal stack is set.
+				// Luckily, all the functions from thread entry to setting the signal
+				// stack have small frames.
+				q1 = obj.Appendp(q, c.newprog)
+				q1.As = AMOVD
+				q1.Pos = p.Pos
+				q1.From.Type = obj.TYPE_REG
+				q1.From.Reg = REGLINK
+				q1.To.Type = obj.TYPE_MEM
+				q1.Scond = C_XPRE
+				q1.To.Offset = int64(-aoffset)
+				q1.To.Reg = REGSP
+				q1.Spadj = aoffset
+
+				prologueEnd = q1
+
+				// Frame pointer.
+				q1 = obj.Appendp(q1, c.newprog)
+				q1.Pos = p.Pos
+				q1.As = AMOVD
+				q1.From.Type = obj.TYPE_REG
+				q1.From.Reg = REGFP
+				q1.To.Type = obj.TYPE_MEM
+				q1.To.Reg = REGSP
+				q1.To.Offset = -8
+			}
+
+			prologueEnd.Pos = prologueEnd.Pos.WithXlogue(src.PosPrologueEnd)
+
+			q1 = obj.Appendp(q1, c.newprog)
+			q1.Pos = p.Pos
+			q1.As = ASUB
+			q1.From.Type = obj.TYPE_CONST
+			q1.From.Offset = 8
+			q1.Reg = REGSP
+			q1.To.Type = obj.TYPE_REG
+			q1.To.Reg = REGFP
+
+			if c.cursym.Func().Text.From.Sym.Wrapper() {
+				// if(g->panic != nil && g->panic->argp == FP) g->panic->argp = bottom-of-frame
+				//
+				//	MOV  g_panic(g), RT1
+				//	CBNZ checkargp
+				// end:
+				//	NOP
+				// ... function body ...
+				// checkargp:
+				//	MOV  panic_argp(RT1), RT2
+				//	ADD  $(autosize+8), RSP, R20
+				//	CMP  RT2, R20
+				//	BNE  end
+				//	ADD  $8, RSP, R20
+				//	MOVD R20, panic_argp(RT1)
+				//	B    end
+				//
+				// The NOP is needed to give the jumps somewhere to land.
+				// It is a liblink NOP, not an ARM64 NOP: it encodes to 0 instruction bytes.
+				q = q1
+
+				// MOV g_panic(g), RT1
+				q = obj.Appendp(q, c.newprog)
+				q.As = AMOVD
+				q.From.Type = obj.TYPE_MEM
+				q.From.Reg = REGG
+				q.From.Offset = 4 * int64(c.ctxt.Arch.PtrSize) // G.panic
+				q.To.Type = obj.TYPE_REG
+				q.To.Reg = REGRT1
+
+				// CBNZ RT1, checkargp
+				cbnz := obj.Appendp(q, c.newprog)
+				cbnz.As = ACBNZ
+				cbnz.From.Type = obj.TYPE_REG
+				cbnz.From.Reg = REGRT1
+				cbnz.To.Type = obj.TYPE_BRANCH
+
+				// Empty branch target at the top of the function body
+				end := obj.Appendp(cbnz, c.newprog)
+				end.As = obj.ANOP
+
+				// find the end of the function
+				var last *obj.Prog
+				for last = end; last.Link != nil; last = last.Link {
+				}
+
+				// MOV panic_argp(RT1), RT2
+				mov := obj.Appendp(last, c.newprog)
+				mov.As = AMOVD
+				mov.From.Type = obj.TYPE_MEM
+				mov.From.Reg = REGRT1
+				mov.From.Offset = 0 // Panic.argp
+				mov.To.Type = obj.TYPE_REG
+				mov.To.Reg = REGRT2
+
+				// CBNZ branches to the MOV above
+				cbnz.To.SetTarget(mov)
+
+				// ADD $(autosize+8), SP, R20
+				q = obj.Appendp(mov, c.newprog)
+				q.As = AADD
+				q.From.Type = obj.TYPE_CONST
+				q.From.Offset = int64(c.autosize) + 8
+				q.Reg = REGSP
+				q.To.Type = obj.TYPE_REG
+				q.To.Reg = REG_R20
+
+				// CMP RT2, R20
+				q = obj.Appendp(q, c.newprog)
+				q.As = ACMP
+				q.From.Type = obj.TYPE_REG
+				q.From.Reg = REGRT2
+				q.Reg = REG_R20
+
+				// BNE end
+				q = obj.Appendp(q, c.newprog)
+				q.As = ABNE
+				q.To.Type = obj.TYPE_BRANCH
+				q.To.SetTarget(end)
+
+				// ADD $8, SP, R20
+				q = obj.Appendp(q, c.newprog)
+				q.As = AADD
+				q.From.Type = obj.TYPE_CONST
+				q.From.Offset = 8
+				q.Reg = REGSP
+				q.To.Type = obj.TYPE_REG
+				q.To.Reg = REG_R20
+
+				// MOV R20, panic_argp(RT1)
+				q = obj.Appendp(q, c.newprog)
+				q.As = AMOVD
+				q.From.Type = obj.TYPE_REG
+				q.From.Reg = REG_R20
+				q.To.Type = obj.TYPE_MEM
+				q.To.Reg = REGRT1
+				q.To.Offset = 0 // Panic.argp
+
+				// B end
+				q = obj.Appendp(q, c.newprog)
+				q.As = AB
+				q.To.Type = obj.TYPE_BRANCH
+				q.To.SetTarget(end)
+			}
+
+		case obj.ARET:
+			nocache(p)
+			if p.From.Type == obj.TYPE_CONST {
+				c.ctxt.Diag("using BECOME (%v) is not supported!", p)
+				break
+			}
+
+			retjmp = p.To.Sym
+			p.To = obj.Addr{}
+			if c.cursym.Func().Text.Mark&LEAF != 0 {
+				if c.autosize != 0 {
+					// Restore frame pointer.
+					// ADD $framesize-8, RSP, R29
+					p.As = AADD
+					p.From.Type = obj.TYPE_CONST
+					p.From.Offset = int64(c.autosize) - 8
+					p.Reg = REGSP
+					p.To.Type = obj.TYPE_REG
+					p.To.Reg = REGFP
+
+					// Pop stack frame.
+					// ADD $framesize, RSP, RSP
+					p = obj.Appendp(p, c.newprog)
+					p.As = AADD
+					p.From.Type = obj.TYPE_CONST
+					p.From.Offset = int64(c.autosize)
+					p.To.Type = obj.TYPE_REG
+					p.To.Reg = REGSP
+					p.Spadj = -c.autosize
+				}
+			} else {
+				aoffset := c.autosize
+				// LDP -8(RSP), (R29, R30)
+				p.As = ALDP
+				p.From.Type = obj.TYPE_MEM
+				p.From.Offset = -8
+				p.From.Reg = REGSP
+				p.To.Type = obj.TYPE_REGREG
+				p.To.Reg = REGFP
+				p.To.Offset = REGLINK
+
+				// ADD $aoffset, RSP, RSP
+				q = newprog()
+				q.As = AADD
+				q.From.Type = obj.TYPE_CONST
+				q.From.Offset = int64(aoffset)
+				q.To.Type = obj.TYPE_REG
+				q.To.Reg = REGSP
+				q.Spadj = -aoffset
+				q.Pos = p.Pos
+				q.Link = p.Link
+				p.Link = q
+				p = q
+			}
+
+			// If enabled, this code emits 'MOV PC, R27' before every 'MOV LR, PC',
+			// so that if you are debugging a low-level crash where PC and LR are zero,
+			// you can look at R27 to see what jumped to the zero.
+			// This is useful when bringing up Go on a new system.
+			// (There is similar code in ../ppc64/obj9.go:/if.false.)
+			const debugRETZERO = false
+			if debugRETZERO {
+				if p.As != obj.ARET {
+					q = newprog()
+					q.Pos = p.Pos
+					q.Link = p.Link
+					p.Link = q
+					p = q
+				}
+				p.As = AADR
+				p.From.Type = obj.TYPE_BRANCH
+				p.From.Offset = 0
+				p.To.Type = obj.TYPE_REG
+				p.To.Reg = REGTMP
+
+			}
+
+			if p.As != obj.ARET {
+				q = newprog()
+				q.Pos = p.Pos
+				q.Link = p.Link
+				p.Link = q
+				p = q
+			}
+
+			if retjmp != nil { // retjmp
+				p.As = AB
+				p.To.Type = obj.TYPE_BRANCH
+				p.To.Sym = retjmp
+				p.Spadj = +c.autosize
+				break
+			}
+
+			p.As = obj.ARET
+			p.To.Type = obj.TYPE_MEM
+			p.To.Offset = 0
+			p.To.Reg = REGLINK
+			p.Spadj = +c.autosize
+
+		case AADD, ASUB:
+			if p.To.Type == obj.TYPE_REG && p.To.Reg == REGSP && p.From.Type == obj.TYPE_CONST {
+				if p.As == AADD {
+					p.Spadj = int32(-p.From.Offset)
+				} else {
+					p.Spadj = int32(+p.From.Offset)
+				}
+			}
+
+		case obj.AGETCALLERPC:
+			if cursym.Leaf() {
+				/* MOVD LR, Rd */
+				p.As = AMOVD
+				p.From.Type = obj.TYPE_REG
+				p.From.Reg = REGLINK
+			} else {
+				/* MOVD (RSP), Rd */
+				p.As = AMOVD
+				p.From.Type = obj.TYPE_MEM
+				p.From.Reg = REGSP
+			}
+
+		case obj.ADUFFCOPY:
+			//  ADR	ret_addr, R27
+			//  STP	(FP, R27), -24(SP)
+			//  SUB	24, SP, FP
+			//  DUFFCOPY
+			// ret_addr:
+			//  SUB	8, SP, FP
+
+			q1 := p
+			// copy DUFFCOPY from q1 to q4
+			q4 := obj.Appendp(p, c.newprog)
+			q4.Pos = p.Pos
+			q4.As = obj.ADUFFCOPY
+			q4.To = p.To
+
+			q1.As = AADR
+			q1.From.Type = obj.TYPE_BRANCH
+			q1.To.Type = obj.TYPE_REG
+			q1.To.Reg = REG_R27
+
+			q2 := obj.Appendp(q1, c.newprog)
+			q2.Pos = p.Pos
+			q2.As = ASTP
+			q2.From.Type = obj.TYPE_REGREG
+			q2.From.Reg = REGFP
+			q2.From.Offset = int64(REG_R27)
+			q2.To.Type = obj.TYPE_MEM
+			q2.To.Reg = REGSP
+			q2.To.Offset = -24
+
+			// maintain FP for DUFFCOPY
+			q3 := obj.Appendp(q2, c.newprog)
+			q3.Pos = p.Pos
+			q3.As = ASUB
+			q3.From.Type = obj.TYPE_CONST
+			q3.From.Offset = 24
+			q3.Reg = REGSP
+			q3.To.Type = obj.TYPE_REG
+			q3.To.Reg = REGFP
+
+			q5 := obj.Appendp(q4, c.newprog)
+			q5.Pos = p.Pos
+			q5.As = ASUB
+			q5.From.Type = obj.TYPE_CONST
+			q5.From.Offset = 8
+			q5.Reg = REGSP
+			q5.To.Type = obj.TYPE_REG
+			q5.To.Reg = REGFP
+			q1.From.SetTarget(q5)
+			p = q5
+
+		case obj.ADUFFZERO:
+			//  ADR	ret_addr, R27
+			//  STP	(FP, R27), -24(SP)
+			//  SUB	24, SP, FP
+			//  DUFFZERO
+			// ret_addr:
+			//  SUB	8, SP, FP
+
+			q1 := p
+			// copy DUFFZERO from q1 to q4
+			q4 := obj.Appendp(p, c.newprog)
+			q4.Pos = p.Pos
+			q4.As = obj.ADUFFZERO
+			q4.To = p.To
+
+			q1.As = AADR
+			q1.From.Type = obj.TYPE_BRANCH
+			q1.To.Type = obj.TYPE_REG
+			q1.To.Reg = REG_R27
+
+			q2 := obj.Appendp(q1, c.newprog)
+			q2.Pos = p.Pos
+			q2.As = ASTP
+			q2.From.Type = obj.TYPE_REGREG
+			q2.From.Reg = REGFP
+			q2.From.Offset = int64(REG_R27)
+			q2.To.Type = obj.TYPE_MEM
+			q2.To.Reg = REGSP
+			q2.To.Offset = -24
+
+			// maintain FP for DUFFZERO
+			q3 := obj.Appendp(q2, c.newprog)
+			q3.Pos = p.Pos
+			q3.As = ASUB
+			q3.From.Type = obj.TYPE_CONST
+			q3.From.Offset = 24
+			q3.Reg = REGSP
+			q3.To.Type = obj.TYPE_REG
+			q3.To.Reg = REGFP
+
+			q5 := obj.Appendp(q4, c.newprog)
+			q5.Pos = p.Pos
+			q5.As = ASUB
+			q5.From.Type = obj.TYPE_CONST
+			q5.From.Offset = 8
+			q5.Reg = REGSP
+			q5.To.Type = obj.TYPE_REG
+			q5.To.Reg = REGFP
+			q1.From.SetTarget(q5)
+			p = q5
+		}
+
+		if p.To.Type == obj.TYPE_REG && p.To.Reg == REGSP && p.Spadj == 0 {
+			f := c.cursym.Func()
+			if f.FuncFlag&abi.FuncFlagSPWrite == 0 {
+				c.cursym.Func().FuncFlag |= abi.FuncFlagSPWrite
+				if ctxt.Debugvlog || !ctxt.IsAsm {
+					ctxt.Logf("auto-SPWRITE: %s %v\n", c.cursym.Name, p)
+					if !ctxt.IsAsm {
+						ctxt.Diag("invalid auto-SPWRITE in non-assembly")
+						ctxt.DiagFlush()
+						log.Fatalf("bad SPWRITE")
+					}
+				}
+			}
+		}
+		if p.From.Type == obj.TYPE_SHIFT && (p.To.Reg == REG_RSP || p.Reg == REG_RSP) {
+			offset := p.From.Offset
+			op := offset & (3 << 22)
+			if op != SHIFT_LL {
+				ctxt.Diag("illegal combination: %v", p)
+			}
+			r := (offset >> 16) & 31
+			shift := (offset >> 10) & 63
+			if shift > 4 {
+				// the shift amount is out of range, in order to avoid repeated error
+				// reportings, don't call ctxt.Diag, because asmout case 27 has the
+				// same check.
+				shift = 7
+			}
+			p.From.Type = obj.TYPE_REG
+			p.From.Reg = int16(REG_LSL + r + (shift&7)<<5)
+			p.From.Offset = 0
+		}
+	}
+}
+
+func nocache(p *obj.Prog) {
+	p.Optab = 0
+	p.From.Class = 0
+	p.To.Class = 0
+}
+
+var unaryDst = map[obj.As]bool{
+	AWORD:  true,
+	ADWORD: true,
+	ABL:    true,
+	AB:     true,
+	ACLREX: true,
+}
+
+var Linkarm64 = obj.LinkArch{
+	Arch:           sys.ArchARM64,
+	Init:           buildop,
+	Preprocess:     preprocess,
+	Assemble:       span7,
+	Progedit:       progedit,
+	UnaryDst:       unaryDst,
+	DWARFRegisters: ARM64DWARFRegisters,
+}