Add gops agentv0.10.2-dev

1 files changed, 1055 insertions, 0 deletions

diff --git a/vendor/github.com/google/gops/internal/obj/arm/obj5.go b/vendor/github.com/google/gops/internal/obj/arm/obj5.go
new file mode 100644
index 00000000..2c4e39b7
--- /dev/null
+++ b/vendor/github.com/google/gops/internal/obj/arm/obj5.go
@@ -0,0 +1,1055 @@
+// Derived from Inferno utils/5c/swt.c
+// https://bitbucket.org/inferno-os/inferno-os/src/default/utils/5c/swt.c
+//
+//	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 arm
+
+import (
+	"fmt"
+	"log"
+	"math"
+
+	"github.com/google/gops/internal/obj"
+	"github.com/google/gops/internal/sys"
+)
+
+var progedit_tlsfallback *obj.LSym
+
+func progedit(ctxt *obj.Link, p *obj.Prog) {
+	p.From.Class = 0
+	p.To.Class = 0
+
+	// Rewrite B/BL to symbol as TYPE_BRANCH.
+	switch p.As {
+	case AB,
+		ABL,
+		obj.ADUFFZERO,
+		obj.ADUFFCOPY:
+		if p.To.Type == obj.TYPE_MEM && (p.To.Name == obj.NAME_EXTERN || p.To.Name == obj.NAME_STATIC) && p.To.Sym != nil {
+			p.To.Type = obj.TYPE_BRANCH
+		}
+	}
+
+	// Replace TLS register fetches on older ARM processors.
+	switch p.As {
+	// Treat MRC 15, 0, <reg>, C13, C0, 3 specially.
+	case AMRC:
+		if p.To.Offset&0xffff0fff == 0xee1d0f70 {
+			// Because the instruction might be rewritten to a BL which returns in R0
+			// the register must be zero.
+			if p.To.Offset&0xf000 != 0 {
+				ctxt.Diag("%v: TLS MRC instruction must write to R0 as it might get translated into a BL instruction", p.Line())
+			}
+
+			if obj.GOARM < 7 {
+				// Replace it with BL runtime.read_tls_fallback(SB) for ARM CPUs that lack the tls extension.
+				if progedit_tlsfallback == nil {
+					progedit_tlsfallback = obj.Linklookup(ctxt, "runtime.read_tls_fallback", 0)
+				}
+
+				// MOVW	LR, R11
+				p.As = AMOVW
+
+				p.From.Type = obj.TYPE_REG
+				p.From.Reg = REGLINK
+				p.To.Type = obj.TYPE_REG
+				p.To.Reg = REGTMP
+
+				// BL	runtime.read_tls_fallback(SB)
+				p = obj.Appendp(ctxt, p)
+
+				p.As = ABL
+				p.To.Type = obj.TYPE_BRANCH
+				p.To.Sym = progedit_tlsfallback
+				p.To.Offset = 0
+
+				// MOVW	R11, LR
+				p = obj.Appendp(ctxt, p)
+
+				p.As = AMOVW
+				p.From.Type = obj.TYPE_REG
+				p.From.Reg = REGTMP
+				p.To.Type = obj.TYPE_REG
+				p.To.Reg = REGLINK
+				break
+			}
+		}
+
+		// Otherwise, MRC/MCR instructions need no further treatment.
+		p.As = AWORD
+	}
+
+	// Rewrite float constants to values stored in memory.
+	switch p.As {
+	case AMOVF:
+		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("$f32.%08x", i32)
+			s := obj.Linklookup(ctxt, literal, 0)
+			p.From.Type = obj.TYPE_MEM
+			p.From.Sym = s
+			p.From.Name = obj.NAME_EXTERN
+			p.From.Offset = 0
+		}
+
+	case AMOVD:
+		if p.From.Type == obj.TYPE_FCONST && chipfloat5(ctxt, p.From.Val.(float64)) < 0 && (chipzero5(ctxt, p.From.Val.(float64)) < 0 || p.Scond&C_SCOND != C_SCOND_NONE) {
+			i64 := math.Float64bits(p.From.Val.(float64))
+			literal := fmt.Sprintf("$f64.%016x", i64)
+			s := obj.Linklookup(ctxt, literal, 0)
+			p.From.Type = obj.TYPE_MEM
+			p.From.Sym = s
+			p.From.Name = obj.NAME_EXTERN
+			p.From.Offset = 0
+		}
+	}
+
+	if ctxt.Flag_dynlink {
+		rewriteToUseGot(ctxt, p)
+	}
+}
+
+// Rewrite p, if necessary, to access global data via the global offset table.
+func rewriteToUseGot(ctxt *obj.Link, p *obj.Prog) {
+	if p.As == obj.ADUFFCOPY || p.As == obj.ADUFFZERO {
+		//     ADUFFxxx $offset
+		// becomes
+		//     MOVW runtime.duffxxx@GOT, R9
+		//     ADD $offset, R9
+		//     CALL (R9)
+		var sym *obj.LSym
+		if p.As == obj.ADUFFZERO {
+			sym = obj.Linklookup(ctxt, "runtime.duffzero", 0)
+		} else {
+			sym = obj.Linklookup(ctxt, "runtime.duffcopy", 0)
+		}
+		offset := p.To.Offset
+		p.As = AMOVW
+		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 = REG_R9
+		p.To.Name = obj.NAME_NONE
+		p.To.Offset = 0
+		p.To.Sym = nil
+		p1 := obj.Appendp(ctxt, p)
+		p1.As = AADD
+		p1.From.Type = obj.TYPE_CONST
+		p1.From.Offset = offset
+		p1.To.Type = obj.TYPE_REG
+		p1.To.Reg = REG_R9
+		p2 := obj.Appendp(ctxt, p1)
+		p2.As = obj.ACALL
+		p2.To.Type = obj.TYPE_MEM
+		p2.To.Reg = REG_R9
+		return
+	}
+
+	// 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() {
+		// MOVW $sym, Rx becomes MOVW sym@GOT, Rx
+		// MOVW $sym+<off>, Rx becomes MOVW sym@GOT, Rx; ADD <off>, Rx
+		if p.As != AMOVW {
+			ctxt.Diag("do not know how to handle TYPE_ADDR in %v with -dynlink", p)
+		}
+		if p.To.Type != obj.TYPE_REG {
+			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(ctxt, p)
+			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.From3 != nil && p.From3.Name == obj.NAME_EXTERN {
+		ctxt.Diag("don't know how to handle %v with -dynlink", p)
+	}
+	var source *obj.Addr
+	// MOVx sym, Ry becomes MOVW sym@GOT, R9; MOVx (R9), Ry
+	// MOVx Ry, sym becomes MOVW sym@GOT, R9; MOVx Ry, (R9)
+	// 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() {
+			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 == obj.STLSBSS {
+		return
+	}
+	if source.Type != obj.TYPE_MEM {
+		ctxt.Diag("don't know how to handle %v with -dynlink", p)
+	}
+	p1 := obj.Appendp(ctxt, p)
+	p2 := obj.Appendp(ctxt, p1)
+
+	p1.As = AMOVW
+	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 = REG_R9
+
+	p2.As = p.As
+	p2.From = p.From
+	p2.To = p.To
+	if p.From.Name == obj.NAME_EXTERN {
+		p2.From.Reg = REG_R9
+		p2.From.Name = obj.NAME_NONE
+		p2.From.Sym = nil
+	} else if p.To.Name == obj.NAME_EXTERN {
+		p2.To.Reg = REG_R9
+		p2.To.Name = obj.NAME_NONE
+		p2.To.Sym = nil
+	} else {
+		return
+	}
+	obj.Nopout(p)
+}
+
+// Prog.mark
+const (
+	FOLL  = 1 << 0
+	LABEL = 1 << 1
+	LEAF  = 1 << 2
+)
+
+func preprocess(ctxt *obj.Link, cursym *obj.LSym) {
+	autosize := int32(0)
+
+	ctxt.Cursym = cursym
+
+	if cursym.Text == nil || cursym.Text.Link == nil {
+		return
+	}
+
+	softfloat(ctxt, cursym)
+
+	p := cursym.Text
+	autoffset := int32(p.To.Offset)
+	if autoffset < 0 {
+		autoffset = 0
+	}
+	cursym.Locals = autoffset
+	cursym.Args = p.To.Val.(int32)
+
+	/*
+	 * find leaf subroutines
+	 * strip NOPs
+	 * expand RET
+	 * expand BECOME pseudo
+	 */
+	var q1 *obj.Prog
+	var q *obj.Prog
+	for p := cursym.Text; p != nil; p = p.Link {
+		switch p.As {
+		case obj.ATEXT:
+			p.Mark |= LEAF
+
+		case obj.ARET:
+			break
+
+		case ADIV, ADIVU, AMOD, AMODU:
+			q = p
+			if ctxt.Sym_div == nil {
+				initdiv(ctxt)
+			}
+			cursym.Text.Mark &^= LEAF
+			continue
+
+		case obj.ANOP:
+			q1 = p.Link
+			q.Link = q1 /* q is non-nop */
+			if q1 != nil {
+				q1.Mark |= p.Mark
+			}
+			continue
+
+		case ABL,
+			ABX,
+			obj.ADUFFZERO,
+			obj.ADUFFCOPY:
+			cursym.Text.Mark &^= LEAF
+			fallthrough
+
+		case AB,
+			ABEQ,
+			ABNE,
+			ABCS,
+			ABHS,
+			ABCC,
+			ABLO,
+			ABMI,
+			ABPL,
+			ABVS,
+			ABVC,
+			ABHI,
+			ABLS,
+			ABGE,
+			ABLT,
+			ABGT,
+			ABLE:
+			q1 = p.Pcond
+			if q1 != nil {
+				for q1.As == obj.ANOP {
+					q1 = q1.Link
+					p.Pcond = q1
+				}
+			}
+		}
+
+		q = p
+	}
+
+	var p1 *obj.Prog
+	var p2 *obj.Prog
+	var q2 *obj.Prog
+	for p := cursym.Text; p != nil; p = p.Link {
+		o := p.As
+		switch o {
+		case obj.ATEXT:
+			autosize = int32(p.To.Offset + 4)
+			if autosize <= 4 {
+				if cursym.Text.Mark&LEAF != 0 {
+					p.To.Offset = -4
+					autosize = 0
+				}
+			}
+
+			if autosize == 0 && cursym.Text.Mark&LEAF == 0 {
+				if ctxt.Debugvlog != 0 {
+					ctxt.Logf("save suppressed in: %s\n", cursym.Name)
+				}
+
+				cursym.Text.Mark |= LEAF
+			}
+
+			if cursym.Text.Mark&LEAF != 0 {
+				cursym.Set(obj.AttrLeaf, true)
+				if autosize == 0 {
+					break
+				}
+			}
+
+			if p.From3.Offset&obj.NOSPLIT == 0 {
+				p = stacksplit(ctxt, p, autosize) // emit split check
+			}
+
+			// MOVW.W		R14,$-autosize(SP)
+			p = obj.Appendp(ctxt, p)
+
+			p.As = AMOVW
+			p.Scond |= C_WBIT
+			p.From.Type = obj.TYPE_REG
+			p.From.Reg = REGLINK
+			p.To.Type = obj.TYPE_MEM
+			p.To.Offset = int64(-autosize)
+			p.To.Reg = REGSP
+			p.Spadj = autosize
+
+			if cursym.Text.From3.Offset&obj.WRAPPER != 0 {
+				// if(g->panic != nil && g->panic->argp == FP) g->panic->argp = bottom-of-frame
+				//
+				//	MOVW g_panic(g), R1
+				//	CMP $0, R1
+				//	B.EQ end
+				//	MOVW panic_argp(R1), R2
+				//	ADD $(autosize+4), R13, R3
+				//	CMP R2, R3
+				//	B.NE end
+				//	ADD $4, R13, R4
+				//	MOVW R4, panic_argp(R1)
+				// end:
+				//	NOP
+				//
+				// The NOP is needed to give the jumps somewhere to land.
+				// It is a liblink NOP, not an ARM NOP: it encodes to 0 instruction bytes.
+
+				p = obj.Appendp(ctxt, p)
+
+				p.As = AMOVW
+				p.From.Type = obj.TYPE_MEM
+				p.From.Reg = REGG
+				p.From.Offset = 4 * int64(ctxt.Arch.PtrSize) // G.panic
+				p.To.Type = obj.TYPE_REG
+				p.To.Reg = REG_R1
+
+				p = obj.Appendp(ctxt, p)
+				p.As = ACMP
+				p.From.Type = obj.TYPE_CONST
+				p.From.Offset = 0
+				p.Reg = REG_R1
+
+				p = obj.Appendp(ctxt, p)
+				p.As = ABEQ
+				p.To.Type = obj.TYPE_BRANCH
+				p1 = p
+
+				p = obj.Appendp(ctxt, p)
+				p.As = AMOVW
+				p.From.Type = obj.TYPE_MEM
+				p.From.Reg = REG_R1
+				p.From.Offset = 0 // Panic.argp
+				p.To.Type = obj.TYPE_REG
+				p.To.Reg = REG_R2
+
+				p = obj.Appendp(ctxt, p)
+				p.As = AADD
+				p.From.Type = obj.TYPE_CONST
+				p.From.Offset = int64(autosize) + 4
+				p.Reg = REG_R13
+				p.To.Type = obj.TYPE_REG
+				p.To.Reg = REG_R3
+
+				p = obj.Appendp(ctxt, p)
+				p.As = ACMP
+				p.From.Type = obj.TYPE_REG
+				p.From.Reg = REG_R2
+				p.Reg = REG_R3
+
+				p = obj.Appendp(ctxt, p)
+				p.As = ABNE
+				p.To.Type = obj.TYPE_BRANCH
+				p2 = p
+
+				p = obj.Appendp(ctxt, p)
+				p.As = AADD
+				p.From.Type = obj.TYPE_CONST
+				p.From.Offset = 4
+				p.Reg = REG_R13
+				p.To.Type = obj.TYPE_REG
+				p.To.Reg = REG_R4
+
+				p = obj.Appendp(ctxt, p)
+				p.As = AMOVW
+				p.From.Type = obj.TYPE_REG
+				p.From.Reg = REG_R4
+				p.To.Type = obj.TYPE_MEM
+				p.To.Reg = REG_R1
+				p.To.Offset = 0 // Panic.argp
+
+				p = obj.Appendp(ctxt, p)
+
+				p.As = obj.ANOP
+				p1.Pcond = p
+				p2.Pcond = p
+			}
+
+		case obj.ARET:
+			nocache(p)
+			if cursym.Text.Mark&LEAF != 0 {
+				if autosize == 0 {
+					p.As = AB
+					p.From = obj.Addr{}
+					if p.To.Sym != nil { // retjmp
+						p.To.Type = obj.TYPE_BRANCH
+					} else {
+						p.To.Type = obj.TYPE_MEM
+						p.To.Offset = 0
+						p.To.Reg = REGLINK
+					}
+
+					break
+				}
+			}
+
+			p.As = AMOVW
+			p.Scond |= C_PBIT
+			p.From.Type = obj.TYPE_MEM
+			p.From.Offset = int64(autosize)
+			p.From.Reg = REGSP
+			p.To.Type = obj.TYPE_REG
+			p.To.Reg = REGPC
+
+			// If there are instructions following
+			// this ARET, they come from a branch
+			// with the same stackframe, so no spadj.
+			if p.To.Sym != nil { // retjmp
+				p.To.Reg = REGLINK
+				q2 = obj.Appendp(ctxt, p)
+				q2.As = AB
+				q2.To.Type = obj.TYPE_BRANCH
+				q2.To.Sym = p.To.Sym
+				p.To.Sym = nil
+				p = q2
+			}
+
+		case AADD:
+			if p.From.Type == obj.TYPE_CONST && p.From.Reg == 0 && p.To.Type == obj.TYPE_REG && p.To.Reg == REGSP {
+				p.Spadj = int32(-p.From.Offset)
+			}
+
+		case ASUB:
+			if p.From.Type == obj.TYPE_CONST && p.From.Reg == 0 && p.To.Type == obj.TYPE_REG && p.To.Reg == REGSP {
+				p.Spadj = int32(p.From.Offset)
+			}
+
+		case ADIV, ADIVU, AMOD, AMODU:
+			if cursym.Text.From3.Offset&obj.NOSPLIT != 0 {
+				ctxt.Diag("cannot divide in NOSPLIT function")
+			}
+			if ctxt.Debugdivmod != 0 {
+				break
+			}
+			if p.From.Type != obj.TYPE_REG {
+				break
+			}
+			if p.To.Type != obj.TYPE_REG {
+				break
+			}
+
+			// Make copy because we overwrite p below.
+			q1 := *p
+			if q1.Reg == REGTMP || q1.Reg == 0 && q1.To.Reg == REGTMP {
+				ctxt.Diag("div already using REGTMP: %v", p)
+			}
+
+			/* MOV m(g),REGTMP */
+			p.As = AMOVW
+			p.Lineno = q1.Lineno
+			p.From.Type = obj.TYPE_MEM
+			p.From.Reg = REGG
+			p.From.Offset = 6 * 4 // offset of g.m
+			p.Reg = 0
+			p.To.Type = obj.TYPE_REG
+			p.To.Reg = REGTMP
+
+			/* MOV a,m_divmod(REGTMP) */
+			p = obj.Appendp(ctxt, p)
+			p.As = AMOVW
+			p.Lineno = q1.Lineno
+			p.From.Type = obj.TYPE_REG
+			p.From.Reg = q1.From.Reg
+			p.To.Type = obj.TYPE_MEM
+			p.To.Reg = REGTMP
+			p.To.Offset = 8 * 4 // offset of m.divmod
+
+			/* MOV b, R8 */
+			p = obj.Appendp(ctxt, p)
+			p.As = AMOVW
+			p.Lineno = q1.Lineno
+			p.From.Type = obj.TYPE_REG
+			p.From.Reg = q1.Reg
+			if q1.Reg == 0 {
+				p.From.Reg = q1.To.Reg
+			}
+			p.To.Type = obj.TYPE_REG
+			p.To.Reg = REG_R8
+			p.To.Offset = 0
+
+			/* CALL appropriate */
+			p = obj.Appendp(ctxt, p)
+			p.As = ABL
+			p.Lineno = q1.Lineno
+			p.To.Type = obj.TYPE_BRANCH
+			switch o {
+			case ADIV:
+				p.To.Sym = ctxt.Sym_div
+
+			case ADIVU:
+				p.To.Sym = ctxt.Sym_divu
+
+			case AMOD:
+				p.To.Sym = ctxt.Sym_mod
+
+			case AMODU:
+				p.To.Sym = ctxt.Sym_modu
+			}
+
+			/* MOV REGTMP, b */
+			p = obj.Appendp(ctxt, p)
+			p.As = AMOVW
+			p.Lineno = q1.Lineno
+			p.From.Type = obj.TYPE_REG
+			p.From.Reg = REGTMP
+			p.From.Offset = 0
+			p.To.Type = obj.TYPE_REG
+			p.To.Reg = q1.To.Reg
+
+		case AMOVW:
+			if (p.Scond&C_WBIT != 0) && p.To.Type == obj.TYPE_MEM && p.To.Reg == REGSP {
+				p.Spadj = int32(-p.To.Offset)
+			}
+			if (p.Scond&C_PBIT != 0) && p.From.Type == obj.TYPE_MEM && p.From.Reg == REGSP && p.To.Reg != REGPC {
+				p.Spadj = int32(-p.From.Offset)
+			}
+			if p.From.Type == obj.TYPE_ADDR && p.From.Reg == REGSP && p.To.Type == obj.TYPE_REG && p.To.Reg == REGSP {
+				p.Spadj = int32(-p.From.Offset)
+			}
+		}
+	}
+}
+
+func isfloatreg(a *obj.Addr) bool {
+	return a.Type == obj.TYPE_REG && REG_F0 <= a.Reg && a.Reg <= REG_F15
+}
+
+func softfloat(ctxt *obj.Link, cursym *obj.LSym) {
+	if obj.GOARM > 5 {
+		return
+	}
+
+	symsfloat := obj.Linklookup(ctxt, "_sfloat", 0)
+
+	wasfloat := 0
+	for p := cursym.Text; p != nil; p = p.Link {
+		if p.Pcond != nil {
+			p.Pcond.Mark |= LABEL
+		}
+	}
+	var next *obj.Prog
+	for p := cursym.Text; p != nil; p = p.Link {
+		switch p.As {
+		case AMOVW:
+			if isfloatreg(&p.To) || isfloatreg(&p.From) {
+				goto soft
+			}
+			goto notsoft
+
+		case AMOVWD,
+			AMOVWF,
+			AMOVDW,
+			AMOVFW,
+			AMOVFD,
+			AMOVDF,
+			AMOVF,
+			AMOVD,
+			ACMPF,
+			ACMPD,
+			AADDF,
+			AADDD,
+			ASUBF,
+			ASUBD,
+			AMULF,
+			AMULD,
+			ADIVF,
+			ADIVD,
+			ASQRTF,
+			ASQRTD,
+			AABSF,
+			AABSD,
+			ANEGF,
+			ANEGD:
+			goto soft
+
+		default:
+			goto notsoft
+		}
+
+	soft:
+		if wasfloat == 0 || (p.Mark&LABEL != 0) {
+			next = ctxt.NewProg()
+			*next = *p
+
+			// BL _sfloat(SB)
+			*p = obj.Prog{}
+			p.Ctxt = ctxt
+			p.Link = next
+			p.As = ABL
+			p.To.Type = obj.TYPE_BRANCH
+			p.To.Sym = symsfloat
+			p.Lineno = next.Lineno
+
+			p = next
+			wasfloat = 1
+		}
+
+		continue
+
+	notsoft:
+		wasfloat = 0
+	}
+}
+
+func stacksplit(ctxt *obj.Link, p *obj.Prog, framesize int32) *obj.Prog {
+	// MOVW			g_stackguard(g), R1
+	p = obj.Appendp(ctxt, p)
+
+	p.As = AMOVW
+	p.From.Type = obj.TYPE_MEM
+	p.From.Reg = REGG
+	p.From.Offset = 2 * int64(ctxt.Arch.PtrSize) // G.stackguard0
+	if ctxt.Cursym.CFunc() {
+		p.From.Offset = 3 * int64(ctxt.Arch.PtrSize) // G.stackguard1
+	}
+	p.To.Type = obj.TYPE_REG
+	p.To.Reg = REG_R1
+
+	if framesize <= obj.StackSmall {
+		// small stack: SP < stackguard
+		//	CMP	stackguard, SP
+		p = obj.Appendp(ctxt, p)
+
+		p.As = ACMP
+		p.From.Type = obj.TYPE_REG
+		p.From.Reg = REG_R1
+		p.Reg = REGSP
+	} else if framesize <= obj.StackBig {
+		// large stack: SP-framesize < stackguard-StackSmall
+		//	MOVW $-framesize(SP), R2
+		//	CMP stackguard, R2
+		p = obj.Appendp(ctxt, p)
+
+		p.As = AMOVW
+		p.From.Type = obj.TYPE_ADDR
+		p.From.Reg = REGSP
+		p.From.Offset = int64(-framesize)
+		p.To.Type = obj.TYPE_REG
+		p.To.Reg = REG_R2
+
+		p = obj.Appendp(ctxt, p)
+		p.As = ACMP
+		p.From.Type = obj.TYPE_REG
+		p.From.Reg = REG_R1
+		p.Reg = REG_R2
+	} else {
+		// Such a large stack we need to protect against wraparound
+		// if SP is close to zero.
+		//	SP-stackguard+StackGuard < framesize + (StackGuard-StackSmall)
+		// The +StackGuard on both sides is required to keep the left side positive:
+		// SP is allowed to be slightly below stackguard. See stack.h.
+		//	CMP $StackPreempt, R1
+		//	MOVW.NE $StackGuard(SP), R2
+		//	SUB.NE R1, R2
+		//	MOVW.NE $(framesize+(StackGuard-StackSmall)), R3
+		//	CMP.NE R3, R2
+		p = obj.Appendp(ctxt, p)
+
+		p.As = ACMP
+		p.From.Type = obj.TYPE_CONST
+		p.From.Offset = int64(uint32(obj.StackPreempt & (1<<32 - 1)))
+		p.Reg = REG_R1
+
+		p = obj.Appendp(ctxt, p)
+		p.As = AMOVW
+		p.From.Type = obj.TYPE_ADDR
+		p.From.Reg = REGSP
+		p.From.Offset = obj.StackGuard
+		p.To.Type = obj.TYPE_REG
+		p.To.Reg = REG_R2
+		p.Scond = C_SCOND_NE
+
+		p = obj.Appendp(ctxt, p)
+		p.As = ASUB
+		p.From.Type = obj.TYPE_REG
+		p.From.Reg = REG_R1
+		p.To.Type = obj.TYPE_REG
+		p.To.Reg = REG_R2
+		p.Scond = C_SCOND_NE
+
+		p = obj.Appendp(ctxt, p)
+		p.As = AMOVW
+		p.From.Type = obj.TYPE_ADDR
+		p.From.Offset = int64(framesize) + (obj.StackGuard - obj.StackSmall)
+		p.To.Type = obj.TYPE_REG
+		p.To.Reg = REG_R3
+		p.Scond = C_SCOND_NE
+
+		p = obj.Appendp(ctxt, p)
+		p.As = ACMP
+		p.From.Type = obj.TYPE_REG
+		p.From.Reg = REG_R3
+		p.Reg = REG_R2
+		p.Scond = C_SCOND_NE
+	}
+
+	// BLS call-to-morestack
+	bls := obj.Appendp(ctxt, p)
+	bls.As = ABLS
+	bls.To.Type = obj.TYPE_BRANCH
+
+	var last *obj.Prog
+	for last = ctxt.Cursym.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(ctxt, last)
+	spfix.As = obj.ANOP
+	spfix.Spadj = -framesize
+
+	pcdata := obj.Appendp(ctxt, spfix)
+	pcdata.Lineno = ctxt.Cursym.Text.Lineno
+	pcdata.Mode = ctxt.Cursym.Text.Mode
+	pcdata.As = obj.APCDATA
+	pcdata.From.Type = obj.TYPE_CONST
+	pcdata.From.Offset = obj.PCDATA_StackMapIndex
+	pcdata.To.Type = obj.TYPE_CONST
+	pcdata.To.Offset = -1 // pcdata starts at -1 at function entry
+
+	// MOVW	LR, R3
+	movw := obj.Appendp(ctxt, pcdata)
+	movw.As = AMOVW
+	movw.From.Type = obj.TYPE_REG
+	movw.From.Reg = REGLINK
+	movw.To.Type = obj.TYPE_REG
+	movw.To.Reg = REG_R3
+
+	bls.Pcond = movw
+
+	// BL runtime.morestack
+	call := obj.Appendp(ctxt, movw)
+	call.As = obj.ACALL
+	call.To.Type = obj.TYPE_BRANCH
+	morestack := "runtime.morestack"
+	switch {
+	case ctxt.Cursym.CFunc():
+		morestack = "runtime.morestackc"
+	case ctxt.Cursym.Text.From3.Offset&obj.NEEDCTXT == 0:
+		morestack = "runtime.morestack_noctxt"
+	}
+	call.To.Sym = obj.Linklookup(ctxt, morestack, 0)
+
+	// B start
+	b := obj.Appendp(ctxt, call)
+	b.As = obj.AJMP
+	b.To.Type = obj.TYPE_BRANCH
+	b.Pcond = ctxt.Cursym.Text.Link
+	b.Spadj = +framesize
+
+	return bls
+}
+
+func initdiv(ctxt *obj.Link) {
+	if ctxt.Sym_div != nil {
+		return
+	}
+	ctxt.Sym_div = obj.Linklookup(ctxt, "_div", 0)
+	ctxt.Sym_divu = obj.Linklookup(ctxt, "_divu", 0)
+	ctxt.Sym_mod = obj.Linklookup(ctxt, "_mod", 0)
+	ctxt.Sym_modu = obj.Linklookup(ctxt, "_modu", 0)
+}
+
+func follow(ctxt *obj.Link, s *obj.LSym) {
+	ctxt.Cursym = s
+
+	firstp := ctxt.NewProg()
+	lastp := firstp
+	xfol(ctxt, s.Text, &lastp)
+	lastp.Link = nil
+	s.Text = firstp.Link
+}
+
+func relinv(a obj.As) obj.As {
+	switch a {
+	case ABEQ:
+		return ABNE
+	case ABNE:
+		return ABEQ
+	case ABCS:
+		return ABCC
+	case ABHS:
+		return ABLO
+	case ABCC:
+		return ABCS
+	case ABLO:
+		return ABHS
+	case ABMI:
+		return ABPL
+	case ABPL:
+		return ABMI
+	case ABVS:
+		return ABVC
+	case ABVC:
+		return ABVS
+	case ABHI:
+		return ABLS
+	case ABLS:
+		return ABHI
+	case ABGE:
+		return ABLT
+	case ABLT:
+		return ABGE
+	case ABGT:
+		return ABLE
+	case ABLE:
+		return ABGT
+	}
+
+	log.Fatalf("unknown relation: %s", Anames[a])
+	return 0
+}
+
+func xfol(ctxt *obj.Link, p *obj.Prog, last **obj.Prog) {
+	var q *obj.Prog
+	var r *obj.Prog
+	var i int
+
+loop:
+	if p == nil {
+		return
+	}
+	a := p.As
+	if a == AB {
+		q = p.Pcond
+		if q != nil && q.As != obj.ATEXT {
+			p.Mark |= FOLL
+			p = q
+			if p.Mark&FOLL == 0 {
+				goto loop
+			}
+		}
+	}
+
+	if p.Mark&FOLL != 0 {
+		i = 0
+		q = p
+		for ; i < 4; i, q = i+1, q.Link {
+			if q == *last || q == nil {
+				break
+			}
+			a = q.As
+			if a == obj.ANOP {
+				i--
+				continue
+			}
+
+			if a == AB || (a == obj.ARET && q.Scond == C_SCOND_NONE) || a == ARFE || a == obj.AUNDEF {
+				goto copy
+			}
+			if q.Pcond == nil || (q.Pcond.Mark&FOLL != 0) {
+				continue
+			}
+			if a != ABEQ && a != ABNE {
+				continue
+			}
+
+		copy:
+			for {
+				r = ctxt.NewProg()
+				*r = *p
+				if r.Mark&FOLL == 0 {
+					fmt.Printf("can't happen 1\n")
+				}
+				r.Mark |= FOLL
+				if p != q {
+					p = p.Link
+					(*last).Link = r
+					*last = r
+					continue
+				}
+
+				(*last).Link = r
+				*last = r
+				if a == AB || (a == obj.ARET && q.Scond == C_SCOND_NONE) || a == ARFE || a == obj.AUNDEF {
+					return
+				}
+				r.As = ABNE
+				if a == ABNE {
+					r.As = ABEQ
+				}
+				r.Pcond = p.Link
+				r.Link = p.Pcond
+				if r.Link.Mark&FOLL == 0 {
+					xfol(ctxt, r.Link, last)
+				}
+				if r.Pcond.Mark&FOLL == 0 {
+					fmt.Printf("can't happen 2\n")
+				}
+				return
+			}
+		}
+
+		a = AB
+		q = ctxt.NewProg()
+		q.As = a
+		q.Lineno = p.Lineno
+		q.To.Type = obj.TYPE_BRANCH
+		q.To.Offset = p.Pc
+		q.Pcond = p
+		p = q
+	}
+
+	p.Mark |= FOLL
+	(*last).Link = p
+	*last = p
+	if a == AB || (a == obj.ARET && p.Scond == C_SCOND_NONE) || a == ARFE || a == obj.AUNDEF {
+		return
+	}
+
+	if p.Pcond != nil {
+		if a != ABL && a != ABX && p.Link != nil {
+			q = obj.Brchain(ctxt, p.Link)
+			if a != obj.ATEXT {
+				if q != nil && (q.Mark&FOLL != 0) {
+					p.As = relinv(a)
+					p.Link = p.Pcond
+					p.Pcond = q
+				}
+			}
+
+			xfol(ctxt, p.Link, last)
+			q = obj.Brchain(ctxt, p.Pcond)
+			if q == nil {
+				q = p.Pcond
+			}
+			if q.Mark&FOLL != 0 {
+				p.Pcond = q
+				return
+			}
+
+			p = q
+			goto loop
+		}
+	}
+
+	p = p.Link
+	goto loop
+}
+
+var unaryDst = map[obj.As]bool{
+	ASWI:  true,
+	AWORD: true,
+}
+
+var Linkarm = obj.LinkArch{
+	Arch:       sys.ArchARM,
+	Preprocess: preprocess,
+	Assemble:   span5,
+	Follow:     follow,
+	Progedit:   progedit,
+	UnaryDst:   unaryDst,
+}