Add gops agentv0.10.2-dev

1 files changed, 1251 insertions, 0 deletions

diff --git a/vendor/github.com/google/gops/internal/obj/ppc64/obj9.go b/vendor/github.com/google/gops/internal/obj/ppc64/obj9.go
new file mode 100644
index 00000000..6cff162c
--- /dev/null
+++ b/vendor/github.com/google/gops/internal/obj/ppc64/obj9.go
@@ -0,0 +1,1251 @@
+// cmd/9l/noop.c, cmd/9l/pass.c, cmd/9l/span.c from Vita Nuova.
+//
+//	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 © 2000-2008 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 © 2000-2008 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 ppc64
+
+import (
+	"fmt"
+	"math"
+
+	"github.com/google/gops/internal/obj"
+	"github.com/google/gops/internal/sys"
+)
+
+func progedit(ctxt *obj.Link, p *obj.Prog) {
+	p.From.Class = 0
+	p.To.Class = 0
+
+	// Rewrite BR/BL to symbol as TYPE_BRANCH.
+	switch p.As {
+	case ABR,
+		ABL,
+		obj.ARET,
+		obj.ADUFFZERO,
+		obj.ADUFFCOPY:
+		if p.To.Sym != nil {
+			p.To.Type = obj.TYPE_BRANCH
+		}
+	}
+
+	// Rewrite float constants to values stored in memory.
+	switch p.As {
+	case AFMOVS:
+		if p.From.Type == obj.TYPE_FCONST {
+			f32 := float32(p.From.Val.(float64))
+			i32 := math.Float32bits(f32)
+			literal := fmt.Sprintf("$f32.%08x", i32)
+			s := obj.Linklookup(ctxt, literal, 0)
+			s.Size = 4
+			p.From.Type = obj.TYPE_MEM
+			p.From.Sym = s
+			p.From.Sym.Set(obj.AttrLocal, true)
+			p.From.Name = obj.NAME_EXTERN
+			p.From.Offset = 0
+		}
+
+	case AFMOVD:
+		if p.From.Type == obj.TYPE_FCONST {
+			i64 := math.Float64bits(p.From.Val.(float64))
+			literal := fmt.Sprintf("$f64.%016x", i64)
+			s := obj.Linklookup(ctxt, literal, 0)
+			s.Size = 8
+			p.From.Type = obj.TYPE_MEM
+			p.From.Sym = s
+			p.From.Sym.Set(obj.AttrLocal, true)
+			p.From.Name = obj.NAME_EXTERN
+			p.From.Offset = 0
+		}
+
+		// Put >32-bit constants in memory and load them
+	case AMOVD:
+		if p.From.Type == obj.TYPE_CONST && p.From.Name == obj.NAME_NONE && p.From.Reg == 0 && int64(int32(p.From.Offset)) != p.From.Offset {
+			literal := fmt.Sprintf("$i64.%016x", uint64(p.From.Offset))
+			s := obj.Linklookup(ctxt, literal, 0)
+			s.Size = 8
+			p.From.Type = obj.TYPE_MEM
+			p.From.Sym = s
+			p.From.Sym.Set(obj.AttrLocal, true)
+			p.From.Name = obj.NAME_EXTERN
+			p.From.Offset = 0
+		}
+	}
+
+	// Rewrite SUB constants into ADD.
+	switch p.As {
+	case ASUBC:
+		if p.From.Type == obj.TYPE_CONST {
+			p.From.Offset = -p.From.Offset
+			p.As = AADDC
+		}
+
+	case ASUBCCC:
+		if p.From.Type == obj.TYPE_CONST {
+			p.From.Offset = -p.From.Offset
+			p.As = AADDCCC
+		}
+
+	case ASUB:
+		if p.From.Type == obj.TYPE_CONST {
+			p.From.Offset = -p.From.Offset
+			p.As = AADD
+		}
+	}
+	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
+		//     MOVD runtime.duffxxx@GOT, R12
+		//     ADD $offset, R12
+		//     MOVD R12, CTR
+		//     BL (CTR)
+		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 = 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 = REG_R12
+		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_R12
+		p2 := obj.Appendp(ctxt, p1)
+		p2.As = AMOVD
+		p2.From.Type = obj.TYPE_REG
+		p2.From.Reg = REG_R12
+		p2.To.Type = obj.TYPE_REG
+		p2.To.Reg = REG_CTR
+		p3 := obj.Appendp(ctxt, p2)
+		p3.As = obj.ACALL
+		p3.From.Type = obj.TYPE_REG
+		p3.From.Reg = REG_R12
+		p3.To.Type = obj.TYPE_REG
+		p3.To.Reg = REG_CTR
+	}
+
+	// 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 {
+			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 MOVD sym@GOT, REGTMP; MOVx (REGTMP), Ry
+	// MOVx Ry, sym becomes MOVD sym@GOT, REGTMP; MOVx 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() {
+			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 = 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) {
+	// TODO(minux): add morestack short-cuts with small fixed frame-size.
+	ctxt.Cursym = cursym
+
+	if cursym.Text == nil || cursym.Text.Link == nil {
+		return
+	}
+
+	p := cursym.Text
+	textstksiz := p.To.Offset
+	if textstksiz == -8 {
+		// Compatibility hack.
+		p.From3.Offset |= obj.NOFRAME
+		textstksiz = 0
+	}
+	if textstksiz%8 != 0 {
+		ctxt.Diag("frame size %d not a multiple of 8", textstksiz)
+	}
+	if p.From3.Offset&obj.NOFRAME != 0 {
+		if textstksiz != 0 {
+			ctxt.Diag("NOFRAME functions must have a frame size of 0, not %d", textstksiz)
+		}
+	}
+
+	cursym.Args = p.To.Val.(int32)
+	cursym.Locals = int32(textstksiz)
+
+	/*
+	 * find leaf subroutines
+	 * strip NOPs
+	 * expand RET
+	 * expand BECOME pseudo
+	 */
+	if ctxt.Debugvlog != 0 {
+		ctxt.Logf("%5.2f noops\n", obj.Cputime())
+	}
+
+	var q *obj.Prog
+	var q1 *obj.Prog
+	for p := cursym.Text; p != nil; p = p.Link {
+		switch p.As {
+		/* too hard, just leave alone */
+		case obj.ATEXT:
+			q = p
+
+			p.Mark |= LABEL | LEAF | SYNC
+			if p.Link != nil {
+				p.Link.Mark |= LABEL
+			}
+
+		case ANOR:
+			q = p
+			if p.To.Type == obj.TYPE_REG {
+				if p.To.Reg == REGZERO {
+					p.Mark |= LABEL | SYNC
+				}
+			}
+
+		case ALWAR,
+			ALBAR,
+			ASTBCCC,
+			ASTWCCC,
+			AECIWX,
+			AECOWX,
+			AEIEIO,
+			AICBI,
+			AISYNC,
+			ATLBIE,
+			ATLBIEL,
+			ASLBIA,
+			ASLBIE,
+			ASLBMFEE,
+			ASLBMFEV,
+			ASLBMTE,
+			ADCBF,
+			ADCBI,
+			ADCBST,
+			ADCBT,
+			ADCBTST,
+			ADCBZ,
+			ASYNC,
+			ATLBSYNC,
+			APTESYNC,
+			ALWSYNC,
+			ATW,
+			AWORD,
+			ARFI,
+			ARFCI,
+			ARFID,
+			AHRFID:
+			q = p
+			p.Mark |= LABEL | SYNC
+			continue
+
+		case AMOVW, AMOVWZ, AMOVD:
+			q = p
+			if p.From.Reg >= REG_SPECIAL || p.To.Reg >= REG_SPECIAL {
+				p.Mark |= LABEL | SYNC
+			}
+			continue
+
+		case AFABS,
+			AFABSCC,
+			AFADD,
+			AFADDCC,
+			AFCTIW,
+			AFCTIWCC,
+			AFCTIWZ,
+			AFCTIWZCC,
+			AFDIV,
+			AFDIVCC,
+			AFMADD,
+			AFMADDCC,
+			AFMOVD,
+			AFMOVDU,
+			/* case AFMOVDS: */
+			AFMOVS,
+			AFMOVSU,
+
+			/* case AFMOVSD: */
+			AFMSUB,
+			AFMSUBCC,
+			AFMUL,
+			AFMULCC,
+			AFNABS,
+			AFNABSCC,
+			AFNEG,
+			AFNEGCC,
+			AFNMADD,
+			AFNMADDCC,
+			AFNMSUB,
+			AFNMSUBCC,
+			AFRSP,
+			AFRSPCC,
+			AFSUB,
+			AFSUBCC:
+			q = p
+
+			p.Mark |= FLOAT
+			continue
+
+		case ABL,
+			ABCL,
+			obj.ADUFFZERO,
+			obj.ADUFFCOPY:
+			cursym.Text.Mark &^= LEAF
+			fallthrough
+
+		case ABC,
+			ABEQ,
+			ABGE,
+			ABGT,
+			ABLE,
+			ABLT,
+			ABNE,
+			ABR,
+			ABVC,
+			ABVS:
+			p.Mark |= BRANCH
+			q = p
+			q1 = p.Pcond
+			if q1 != nil {
+				for q1.As == obj.ANOP {
+					q1 = q1.Link
+					p.Pcond = q1
+				}
+
+				if q1.Mark&LEAF == 0 {
+					q1.Mark |= LABEL
+				}
+			} else {
+				p.Mark |= LABEL
+			}
+			q1 = p.Link
+			if q1 != nil {
+				q1.Mark |= LABEL
+			}
+			continue
+
+		case AFCMPO, AFCMPU:
+			q = p
+			p.Mark |= FCMP | FLOAT
+			continue
+
+		case obj.ARET:
+			q = p
+			if p.Link != nil {
+				p.Link.Mark |= LABEL
+			}
+			continue
+
+		case obj.ANOP:
+			q1 = p.Link
+			q.Link = q1 /* q is non-nop */
+			q1.Mark |= p.Mark
+			continue
+
+		default:
+			q = p
+			continue
+		}
+	}
+
+	autosize := int32(0)
+	var p1 *obj.Prog
+	var p2 *obj.Prog
+	for p := cursym.Text; p != nil; p = p.Link {
+		o := p.As
+		switch o {
+		case obj.ATEXT:
+			autosize = int32(textstksiz)
+
+			if p.Mark&LEAF != 0 && autosize == 0 {
+				// A leaf function with no locals has no frame.
+				p.From3.Offset |= obj.NOFRAME
+			}
+
+			if p.From3.Offset&obj.NOFRAME == 0 {
+				// If there is a stack frame at all, it includes
+				// space to save the LR.
+				autosize += int32(ctxt.FixedFrameSize())
+			}
+
+			if p.Mark&LEAF != 0 && autosize < obj.StackSmall {
+				// A leaf function with a small stack can be marked
+				// NOSPLIT, avoiding a stack check.
+				p.From3.Offset |= obj.NOSPLIT
+			}
+
+			p.To.Offset = int64(autosize)
+
+			q = p
+
+			if ctxt.Flag_shared && cursym.Name != "runtime.duffzero" && cursym.Name != "runtime.duffcopy" && cursym.Name != "runtime.stackBarrier" {
+				// When compiling Go into PIC, all functions must start
+				// with instructions to load the TOC pointer into r2:
+				//
+				//	addis r2, r12, .TOC.-func@ha
+				//	addi r2, r2, .TOC.-func@l+4
+				//
+				// We could probably skip this prologue in some situations
+				// but it's a bit subtle. However, it is both safe and
+				// necessary to leave the prologue off duffzero and
+				// duffcopy as we rely on being able to jump to a specific
+				// instruction offset for them, and stackBarrier is only
+				// ever called from an overwritten LR-save slot on the
+				// stack (when r12 will not be remotely the right thing)
+				// but fortunately does not access global data.
+				//
+				// These are AWORDS because there is no (afaict) way to
+				// generate the addis instruction except as part of the
+				// load of a large constant, and in that case there is no
+				// way to use r12 as the source.
+				q = obj.Appendp(ctxt, q)
+				q.As = AWORD
+				q.Lineno = p.Lineno
+				q.From.Type = obj.TYPE_CONST
+				q.From.Offset = 0x3c4c0000
+				q = obj.Appendp(ctxt, q)
+				q.As = AWORD
+				q.Lineno = p.Lineno
+				q.From.Type = obj.TYPE_CONST
+				q.From.Offset = 0x38420000
+				rel := obj.Addrel(ctxt.Cursym)
+				rel.Off = 0
+				rel.Siz = 8
+				rel.Sym = obj.Linklookup(ctxt, ".TOC.", 0)
+				rel.Type = obj.R_ADDRPOWER_PCREL
+			}
+
+			if cursym.Text.From3.Offset&obj.NOSPLIT == 0 {
+				q = stacksplit(ctxt, q, autosize) // emit split check
+			}
+
+			if autosize != 0 {
+				// Make sure to save link register for non-empty frame, even if
+				// it is a leaf function, so that traceback works.
+				if cursym.Text.Mark&LEAF == 0 && autosize >= -BIG && autosize <= BIG {
+					// Use MOVDU to adjust R1 when saving R31, if autosize is small.
+					q = obj.Appendp(ctxt, q)
+					q.As = AMOVD
+					q.Lineno = p.Lineno
+					q.From.Type = obj.TYPE_REG
+					q.From.Reg = REG_LR
+					q.To.Type = obj.TYPE_REG
+					q.To.Reg = REGTMP
+
+					q = obj.Appendp(ctxt, q)
+					q.As = AMOVDU
+					q.Lineno = p.Lineno
+					q.From.Type = obj.TYPE_REG
+					q.From.Reg = REGTMP
+					q.To.Type = obj.TYPE_MEM
+					q.To.Offset = int64(-autosize)
+					q.To.Reg = REGSP
+					q.Spadj = int32(autosize)
+				} else {
+					// Frame size is too large for a MOVDU instruction.
+					// Store 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.
+					q = obj.Appendp(ctxt, q)
+					q.As = AMOVD
+					q.Lineno = p.Lineno
+					q.From.Type = obj.TYPE_REG
+					q.From.Reg = REG_LR
+					q.To.Type = obj.TYPE_REG
+					q.To.Reg = REG_R29 // REGTMP may be used to synthesize large offset in the next instruction
+
+					q = obj.Appendp(ctxt, q)
+					q.As = AMOVD
+					q.Lineno = p.Lineno
+					q.From.Type = obj.TYPE_REG
+					q.From.Reg = REG_R29
+					q.To.Type = obj.TYPE_MEM
+					q.To.Offset = int64(-autosize)
+					q.To.Reg = REGSP
+
+					q = obj.Appendp(ctxt, q)
+					q.As = AADD
+					q.Lineno = p.Lineno
+					q.From.Type = obj.TYPE_CONST
+					q.From.Offset = int64(-autosize)
+					q.To.Type = obj.TYPE_REG
+					q.To.Reg = REGSP
+					q.Spadj = +autosize
+				}
+			} else if cursym.Text.Mark&LEAF == 0 {
+				// A very few functions that do not return to their caller
+				// (e.g. gogo) are not identified as leaves but still have
+				// no frame.
+				cursym.Text.Mark |= LEAF
+			}
+
+			if cursym.Text.Mark&LEAF != 0 {
+				cursym.Set(obj.AttrLeaf, true)
+				break
+			}
+
+			if ctxt.Flag_shared {
+				q = obj.Appendp(ctxt, q)
+				q.As = AMOVD
+				q.Lineno = p.Lineno
+				q.From.Type = obj.TYPE_REG
+				q.From.Reg = REG_R2
+				q.To.Type = obj.TYPE_MEM
+				q.To.Reg = REGSP
+				q.To.Offset = 24
+			}
+
+			if cursym.Text.From3.Offset&obj.WRAPPER != 0 {
+				// if(g->panic != nil && g->panic->argp == FP) g->panic->argp = bottom-of-frame
+				//
+				//	MOVD g_panic(g), R3
+				//	CMP R0, R3
+				//	BEQ end
+				//	MOVD panic_argp(R3), R4
+				//	ADD $(autosize+8), R1, R5
+				//	CMP R4, R5
+				//	BNE end
+				//	ADD $8, R1, R6
+				//	MOVD R6, panic_argp(R3)
+				// end:
+				//	NOP
+				//
+				// The NOP is needed to give the jumps somewhere to land.
+				// It is a liblink NOP, not a ppc64 NOP: it encodes to 0 instruction bytes.
+
+				q = obj.Appendp(ctxt, q)
+
+				q.As = AMOVD
+				q.From.Type = obj.TYPE_MEM
+				q.From.Reg = REGG
+				q.From.Offset = 4 * int64(ctxt.Arch.PtrSize) // G.panic
+				q.To.Type = obj.TYPE_REG
+				q.To.Reg = REG_R3
+
+				q = obj.Appendp(ctxt, q)
+				q.As = ACMP
+				q.From.Type = obj.TYPE_REG
+				q.From.Reg = REG_R0
+				q.To.Type = obj.TYPE_REG
+				q.To.Reg = REG_R3
+
+				q = obj.Appendp(ctxt, q)
+				q.As = ABEQ
+				q.To.Type = obj.TYPE_BRANCH
+				p1 = q
+
+				q = obj.Appendp(ctxt, q)
+				q.As = AMOVD
+				q.From.Type = obj.TYPE_MEM
+				q.From.Reg = REG_R3
+				q.From.Offset = 0 // Panic.argp
+				q.To.Type = obj.TYPE_REG
+				q.To.Reg = REG_R4
+
+				q = obj.Appendp(ctxt, q)
+				q.As = AADD
+				q.From.Type = obj.TYPE_CONST
+				q.From.Offset = int64(autosize) + ctxt.FixedFrameSize()
+				q.Reg = REGSP
+				q.To.Type = obj.TYPE_REG
+				q.To.Reg = REG_R5
+
+				q = obj.Appendp(ctxt, q)
+				q.As = ACMP
+				q.From.Type = obj.TYPE_REG
+				q.From.Reg = REG_R4
+				q.To.Type = obj.TYPE_REG
+				q.To.Reg = REG_R5
+
+				q = obj.Appendp(ctxt, q)
+				q.As = ABNE
+				q.To.Type = obj.TYPE_BRANCH
+				p2 = q
+
+				q = obj.Appendp(ctxt, q)
+				q.As = AADD
+				q.From.Type = obj.TYPE_CONST
+				q.From.Offset = ctxt.FixedFrameSize()
+				q.Reg = REGSP
+				q.To.Type = obj.TYPE_REG
+				q.To.Reg = REG_R6
+
+				q = obj.Appendp(ctxt, q)
+				q.As = AMOVD
+				q.From.Type = obj.TYPE_REG
+				q.From.Reg = REG_R6
+				q.To.Type = obj.TYPE_MEM
+				q.To.Reg = REG_R3
+				q.To.Offset = 0 // Panic.argp
+
+				q = obj.Appendp(ctxt, q)
+
+				q.As = obj.ANOP
+				p1.Pcond = q
+				p2.Pcond = q
+			}
+
+		case obj.ARET:
+			if p.From.Type == obj.TYPE_CONST {
+				ctxt.Diag("using BECOME (%v) is not supported!", p)
+				break
+			}
+
+			retTarget := p.To.Sym
+
+			if cursym.Text.Mark&LEAF != 0 {
+				if autosize == 0 {
+					p.As = ABR
+					p.From = obj.Addr{}
+					if retTarget == nil {
+						p.To.Type = obj.TYPE_REG
+						p.To.Reg = REG_LR
+					} else {
+						p.To.Type = obj.TYPE_BRANCH
+						p.To.Sym = retTarget
+					}
+					p.Mark |= BRANCH
+					break
+				}
+
+				p.As = AADD
+				p.From.Type = obj.TYPE_CONST
+				p.From.Offset = int64(autosize)
+				p.To.Type = obj.TYPE_REG
+				p.To.Reg = REGSP
+				p.Spadj = -autosize
+
+				q = ctxt.NewProg()
+				q.As = ABR
+				q.Lineno = p.Lineno
+				q.To.Type = obj.TYPE_REG
+				q.To.Reg = REG_LR
+				q.Mark |= BRANCH
+				q.Spadj = +autosize
+
+				q.Link = p.Link
+				p.Link = q
+				break
+			}
+
+			p.As = AMOVD
+			p.From.Type = obj.TYPE_MEM
+			p.From.Offset = 0
+			p.From.Reg = REGSP
+			p.To.Type = obj.TYPE_REG
+			p.To.Reg = REGTMP
+
+			q = ctxt.NewProg()
+			q.As = AMOVD
+			q.Lineno = p.Lineno
+			q.From.Type = obj.TYPE_REG
+			q.From.Reg = REGTMP
+			q.To.Type = obj.TYPE_REG
+			q.To.Reg = REG_LR
+
+			q.Link = p.Link
+			p.Link = q
+			p = q
+
+			if false {
+				// Debug bad returns
+				q = ctxt.NewProg()
+
+				q.As = AMOVD
+				q.Lineno = p.Lineno
+				q.From.Type = obj.TYPE_MEM
+				q.From.Offset = 0
+				q.From.Reg = REGTMP
+				q.To.Type = obj.TYPE_REG
+				q.To.Reg = REGTMP
+
+				q.Link = p.Link
+				p.Link = q
+				p = q
+			}
+
+			if autosize != 0 {
+				q = ctxt.NewProg()
+				q.As = AADD
+				q.Lineno = p.Lineno
+				q.From.Type = obj.TYPE_CONST
+				q.From.Offset = int64(autosize)
+				q.To.Type = obj.TYPE_REG
+				q.To.Reg = REGSP
+				q.Spadj = -autosize
+
+				q.Link = p.Link
+				p.Link = q
+			}
+
+			q1 = ctxt.NewProg()
+			q1.As = ABR
+			q1.Lineno = p.Lineno
+			if retTarget == nil {
+				q1.To.Type = obj.TYPE_REG
+				q1.To.Reg = REG_LR
+			} else {
+				q1.To.Type = obj.TYPE_BRANCH
+				q1.To.Sym = retTarget
+			}
+			q1.Mark |= BRANCH
+			q1.Spadj = +autosize
+
+			q1.Link = q.Link
+			q.Link = q1
+		case AADD:
+			if p.To.Type == obj.TYPE_REG && p.To.Reg == REGSP && p.From.Type == obj.TYPE_CONST {
+				p.Spadj = int32(-p.From.Offset)
+			}
+		}
+	}
+}
+
+/*
+// instruction scheduling
+	if(debug['Q'] == 0)
+		return;
+
+	curtext = nil;
+	q = nil;	// p - 1
+	q1 = firstp;	// top of block
+	o = 0;		// count of instructions
+	for(p = firstp; p != nil; p = p1) {
+		p1 = p->link;
+		o++;
+		if(p->mark & NOSCHED){
+			if(q1 != p){
+				sched(q1, q);
+			}
+			for(; p != nil; p = p->link){
+				if(!(p->mark & NOSCHED))
+					break;
+				q = p;
+			}
+			p1 = p;
+			q1 = p;
+			o = 0;
+			continue;
+		}
+		if(p->mark & (LABEL|SYNC)) {
+			if(q1 != p)
+				sched(q1, q);
+			q1 = p;
+			o = 1;
+		}
+		if(p->mark & (BRANCH|SYNC)) {
+			sched(q1, p);
+			q1 = p1;
+			o = 0;
+		}
+		if(o >= NSCHED) {
+			sched(q1, p);
+			q1 = p1;
+			o = 0;
+		}
+		q = p;
+	}
+*/
+func stacksplit(ctxt *obj.Link, p *obj.Prog, framesize int32) *obj.Prog {
+	p0 := p // save entry point, but skipping the two instructions setting R2 in shared mode
+
+	// MOVD	g_stackguard(g), R3
+	p = obj.Appendp(ctxt, p)
+
+	p.As = AMOVD
+	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_R3
+
+	var q *obj.Prog
+	if framesize <= obj.StackSmall {
+		// small stack: SP < stackguard
+		//	CMP	stackguard, SP
+		p = obj.Appendp(ctxt, p)
+
+		p.As = ACMPU
+		p.From.Type = obj.TYPE_REG
+		p.From.Reg = REG_R3
+		p.To.Type = obj.TYPE_REG
+		p.To.Reg = REGSP
+	} else if framesize <= obj.StackBig {
+		// large stack: SP-framesize < stackguard-StackSmall
+		//	ADD $-framesize, SP, R4
+		//	CMP stackguard, R4
+		p = obj.Appendp(ctxt, p)
+
+		p.As = AADD
+		p.From.Type = obj.TYPE_CONST
+		p.From.Offset = int64(-framesize)
+		p.Reg = REGSP
+		p.To.Type = obj.TYPE_REG
+		p.To.Reg = REG_R4
+
+		p = obj.Appendp(ctxt, p)
+		p.As = ACMPU
+		p.From.Type = obj.TYPE_REG
+		p.From.Reg = REG_R3
+		p.To.Type = obj.TYPE_REG
+		p.To.Reg = REG_R4
+	} 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.
+		//
+		// Preemption sets stackguard to StackPreempt, a very large value.
+		// That breaks the math above, so we have to check for that explicitly.
+		//	// stackguard is R3
+		//	CMP	R3, $StackPreempt
+		//	BEQ	label-of-call-to-morestack
+		//	ADD	$StackGuard, SP, R4
+		//	SUB	R3, R4
+		//	MOVD	$(framesize+(StackGuard-StackSmall)), R31
+		//	CMPU	R31, R4
+		p = obj.Appendp(ctxt, p)
+
+		p.As = ACMP
+		p.From.Type = obj.TYPE_REG
+		p.From.Reg = REG_R3
+		p.To.Type = obj.TYPE_CONST
+		p.To.Offset = obj.StackPreempt
+
+		p = obj.Appendp(ctxt, p)
+		q = p
+		p.As = ABEQ
+		p.To.Type = obj.TYPE_BRANCH
+
+		p = obj.Appendp(ctxt, p)
+		p.As = AADD
+		p.From.Type = obj.TYPE_CONST
+		p.From.Offset = obj.StackGuard
+		p.Reg = REGSP
+		p.To.Type = obj.TYPE_REG
+		p.To.Reg = REG_R4
+
+		p = obj.Appendp(ctxt, p)
+		p.As = ASUB
+		p.From.Type = obj.TYPE_REG
+		p.From.Reg = REG_R3
+		p.To.Type = obj.TYPE_REG
+		p.To.Reg = REG_R4
+
+		p = obj.Appendp(ctxt, p)
+		p.As = AMOVD
+		p.From.Type = obj.TYPE_CONST
+		p.From.Offset = int64(framesize) + obj.StackGuard - obj.StackSmall
+		p.To.Type = obj.TYPE_REG
+		p.To.Reg = REGTMP
+
+		p = obj.Appendp(ctxt, p)
+		p.As = ACMPU
+		p.From.Type = obj.TYPE_REG
+		p.From.Reg = REGTMP
+		p.To.Type = obj.TYPE_REG
+		p.To.Reg = REG_R4
+	}
+
+	// q1: BLT	done
+	p = obj.Appendp(ctxt, p)
+	q1 := p
+
+	p.As = ABLT
+	p.To.Type = obj.TYPE_BRANCH
+
+	// MOVD	LR, R5
+	p = obj.Appendp(ctxt, p)
+
+	p.As = AMOVD
+	p.From.Type = obj.TYPE_REG
+	p.From.Reg = REG_LR
+	p.To.Type = obj.TYPE_REG
+	p.To.Reg = REG_R5
+	if q != nil {
+		q.Pcond = p
+	}
+
+	var morestacksym *obj.LSym
+	if ctxt.Cursym.CFunc() {
+		morestacksym = obj.Linklookup(ctxt, "runtime.morestackc", 0)
+	} else if ctxt.Cursym.Text.From3.Offset&obj.NEEDCTXT == 0 {
+		morestacksym = obj.Linklookup(ctxt, "runtime.morestack_noctxt", 0)
+	} else {
+		morestacksym = obj.Linklookup(ctxt, "runtime.morestack", 0)
+	}
+
+	if ctxt.Flag_shared {
+		// In PPC64 PIC code, R2 is used as TOC pointer derived from R12
+		// which is the address of function entry point when entering
+		// the function. We need to preserve R2 across call to morestack.
+		// Fortunately, in shared mode, 8(SP) and 16(SP) are reserved in
+		// the caller's frame, but not used (0(SP) is caller's saved LR,
+		// 24(SP) is caller's saved R2). Use 8(SP) to save this function's R2.
+
+		// MOVD R12, 8(SP)
+		p = obj.Appendp(ctxt, p)
+		p.As = AMOVD
+		p.From.Type = obj.TYPE_REG
+		p.From.Reg = REG_R2
+		p.To.Type = obj.TYPE_MEM
+		p.To.Reg = REGSP
+		p.To.Offset = 8
+	}
+
+	if ctxt.Flag_dynlink {
+		// Avoid calling morestack via a PLT when dynamically linking. The
+		// PLT stubs generated by the system linker on ppc64le when "std r2,
+		// 24(r1)" to save the TOC pointer in their callers stack
+		// frame. Unfortunately (and necessarily) morestack is called before
+		// the function that calls it sets up its frame and so the PLT ends
+		// up smashing the saved TOC pointer for its caller's caller.
+		//
+		// According to the ABI documentation there is a mechanism to avoid
+		// the TOC save that the PLT stub does (put a R_PPC64_TOCSAVE
+		// relocation on the nop after the call to morestack) but at the time
+		// of writing it is not supported at all by gold and my attempt to
+		// use it with ld.bfd caused an internal linker error. So this hack
+		// seems preferable.
+
+		// MOVD $runtime.morestack(SB), R12
+		p = obj.Appendp(ctxt, p)
+		p.As = AMOVD
+		p.From.Type = obj.TYPE_MEM
+		p.From.Sym = morestacksym
+		p.From.Name = obj.NAME_GOTREF
+		p.To.Type = obj.TYPE_REG
+		p.To.Reg = REG_R12
+
+		// MOVD R12, CTR
+		p = obj.Appendp(ctxt, p)
+		p.As = AMOVD
+		p.From.Type = obj.TYPE_REG
+		p.From.Reg = REG_R12
+		p.To.Type = obj.TYPE_REG
+		p.To.Reg = REG_CTR
+
+		// BL CTR
+		p = obj.Appendp(ctxt, p)
+		p.As = obj.ACALL
+		p.From.Type = obj.TYPE_REG
+		p.From.Reg = REG_R12
+		p.To.Type = obj.TYPE_REG
+		p.To.Reg = REG_CTR
+	} else {
+		// BL	runtime.morestack(SB)
+		p = obj.Appendp(ctxt, p)
+
+		p.As = ABL
+		p.To.Type = obj.TYPE_BRANCH
+		p.To.Sym = morestacksym
+	}
+
+	if ctxt.Flag_shared {
+		// MOVD 8(SP), R2
+		p = obj.Appendp(ctxt, p)
+		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 = REG_R2
+	}
+
+	// BR	start
+	p = obj.Appendp(ctxt, p)
+	p.As = ABR
+	p.To.Type = obj.TYPE_BRANCH
+	p.Pcond = p0.Link
+
+	// placeholder for q1's jump target
+	p = obj.Appendp(ctxt, p)
+
+	p.As = obj.ANOP // zero-width place holder
+	q1.Pcond = p
+
+	return p
+}
+
+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 ABGE:
+		return ABLT
+	case ABLT:
+		return ABGE
+
+	case ABGT:
+		return ABLE
+	case ABLE:
+		return ABGT
+
+	case ABVC:
+		return ABVS
+	case ABVS:
+		return ABVC
+	}
+
+	return 0
+}
+
+func xfol(ctxt *obj.Link, p *obj.Prog, last **obj.Prog) {
+	var q *obj.Prog
+	var r *obj.Prog
+	var b obj.As
+	var i int
+
+loop:
+	if p == nil {
+		return
+	}
+	a := p.As
+	if a == ABR {
+		q = p.Pcond
+		if (p.Mark&NOSCHED != 0) || q != nil && (q.Mark&NOSCHED != 0) {
+			p.Mark |= FOLL
+			(*last).Link = p
+			*last = p
+			p = p.Link
+			xfol(ctxt, p, last)
+			p = q
+			if p != nil && p.Mark&FOLL == 0 {
+				goto loop
+			}
+			return
+		}
+
+		if q != nil {
+			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.Mark&NOSCHED != 0) {
+				break
+			}
+			b = 0 /* set */
+			a = q.As
+			if a == obj.ANOP {
+				i--
+				continue
+			}
+
+			if a == ABR || a == obj.ARET || a == ARFI || a == ARFCI || a == ARFID || a == AHRFID {
+				goto copy
+			}
+			if q.Pcond == nil || (q.Pcond.Mark&FOLL != 0) {
+				continue
+			}
+			b = relinv(a)
+			if b == 0 {
+				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 == ABR || a == obj.ARET || a == ARFI || a == ARFCI || a == ARFID || a == AHRFID {
+					return
+				}
+				r.As = b
+				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 = ABR
+		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 == ABR || a == obj.ARET || a == ARFI || a == ARFCI || a == ARFID || a == AHRFID {
+		if p.Mark&NOSCHED != 0 {
+			p = p.Link
+			goto loop
+		}
+
+		return
+	}
+
+	if p.Pcond != nil {
+		if a != ABL && p.Link != nil {
+			xfol(ctxt, p.Link, last)
+			p = p.Pcond
+			if p == nil || (p.Mark&FOLL != 0) {
+				return
+			}
+			goto loop
+		}
+	}
+
+	p = p.Link
+	goto loop
+}
+
+var Linkppc64 = obj.LinkArch{
+	Arch:       sys.ArchPPC64,
+	Preprocess: preprocess,
+	Assemble:   span9,
+	Follow:     follow,
+	Progedit:   progedit,
+}
+
+var Linkppc64le = obj.LinkArch{
+	Arch:       sys.ArchPPC64LE,
+	Preprocess: preprocess,
+	Assemble:   span9,
+	Follow:     follow,
+	Progedit:   progedit,
+}