Ejemplo n.º 1
0
Archivo: objz.go Proyecto: hurkgu/go
func stacksplitPost(ctxt *obj.Link, p *obj.Prog, pPre *obj.Prog, pPreempt *obj.Prog) *obj.Prog {

	// MOVD	LR, R5
	p = obj.Appendp(ctxt, p)
	pPre.Pcond = 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 pPreempt != nil {
		pPreempt.Pcond = p
	}

	// BL	runtime.morestack(SB)
	p = obj.Appendp(ctxt, p)

	p.As = ABL
	p.To.Type = obj.TYPE_BRANCH
	if ctxt.Cursym.Cfunc {
		p.To.Sym = obj.Linklookup(ctxt, "runtime.morestackc", 0)
	} else if ctxt.Cursym.Text.From3.Offset&obj.NEEDCTXT == 0 {
		p.To.Sym = obj.Linklookup(ctxt, "runtime.morestack_noctxt", 0)
	} else {
		p.To.Sym = obj.Linklookup(ctxt, "runtime.morestack", 0)
	}

	// BR	start
	p = obj.Appendp(ctxt, p)

	p.As = ABR
	p.To.Type = obj.TYPE_BRANCH
	p.Pcond = ctxt.Cursym.Text.Link
	return p
}
Ejemplo n.º 2
0
// Called after regopt and peep have run.
// Expand CHECKNIL pseudo-op into actual nil pointer check.
func expandchecks(firstp *obj.Prog) {
	var p1 *obj.Prog
	var p2 *obj.Prog

	for p := firstp; p != nil; p = p.Link {
		if p.As != obj.ACHECKNIL {
			continue
		}
		if gc.Debug_checknil != 0 && p.Lineno > 1 { // p->lineno==1 in generated wrappers
			gc.Warnl(int(p.Lineno), "generated nil check")
		}

		// check is
		//	CMP arg, $0
		//	JNE 2(PC) (likely)
		//	MOV AX, 0
		p1 = gc.Ctxt.NewProg()

		p2 = gc.Ctxt.NewProg()
		gc.Clearp(p1)
		gc.Clearp(p2)
		p1.Link = p2
		p2.Link = p.Link
		p.Link = p1
		p1.Lineno = p.Lineno
		p2.Lineno = p.Lineno
		p1.Pc = 9999
		p2.Pc = 9999
		p.As = int16(cmpptr)
		p.To.Type = obj.TYPE_CONST
		p.To.Offset = 0
		p1.As = x86.AJNE
		p1.From.Type = obj.TYPE_CONST
		p1.From.Offset = 1 // likely
		p1.To.Type = obj.TYPE_BRANCH
		p1.To.Val = p2.Link

		// crash by write to memory address 0.
		// if possible, since we know arg is 0, use 0(arg),
		// which will be shorter to encode than plain 0.
		p2.As = x86.AMOVL

		p2.From.Type = obj.TYPE_REG
		p2.From.Reg = x86.REG_AX
		if regtyp(&p.From) {
			p2.To.Type = obj.TYPE_MEM
			p2.To.Reg = p.From.Reg
		} else {
			p2.To.Type = obj.TYPE_MEM
			p2.To.Reg = x86.REG_NONE
		}

		p2.To.Offset = 0
	}
}
Ejemplo n.º 3
0
Archivo: ggen.go Proyecto: tidatida/go
// Called after regopt and peep have run.
// Expand CHECKNIL pseudo-op into actual nil pointer check.
func expandchecks(firstp *obj.Prog) {
	var p1 *obj.Prog
	var p2 *obj.Prog

	for p := (*obj.Prog)(firstp); p != nil; p = p.Link {
		if gc.Debug_checknil != 0 && gc.Ctxt.Debugvlog != 0 {
			fmt.Printf("expandchecks: %v\n", p)
		}
		if p.As != obj.ACHECKNIL {
			continue
		}
		if gc.Debug_checknil != 0 && p.Lineno > 1 { // p->lineno==1 in generated wrappers
			gc.Warnl(int(p.Lineno), "generated nil check")
		}
		if p.From.Type != obj.TYPE_REG {
			gc.Fatal("invalid nil check %v\n", p)
		}

		// check is
		//	CMP arg, ZR
		//	BNE 2(PC) [likely]
		//	MOVD ZR, 0(arg)
		p1 = gc.Ctxt.NewProg()

		p2 = gc.Ctxt.NewProg()
		gc.Clearp(p1)
		gc.Clearp(p2)
		p1.Link = p2
		p2.Link = p.Link
		p.Link = p1
		p1.Lineno = p.Lineno
		p2.Lineno = p.Lineno
		p1.Pc = 9999
		p2.Pc = 9999
		p.As = arm64.ACMP
		p.Reg = arm64.REGZERO
		p1.As = arm64.ABNE

		//p1->from.type = TYPE_CONST;
		//p1->from.offset = 1; // likely
		p1.To.Type = obj.TYPE_BRANCH

		p1.To.Val = p2.Link

		// crash by write to memory address 0.
		p2.As = arm64.AMOVD
		p2.From.Type = obj.TYPE_REG
		p2.From.Reg = arm64.REGZERO
		p2.To.Type = obj.TYPE_MEM
		p2.To.Reg = p.From.Reg
		p2.To.Offset = 0
	}
}
Ejemplo n.º 4
0
func stacksplitPost(ctxt *obj.Link, p *obj.Prog, pPre *obj.Prog, pPreempt *obj.Prog, framesize int32) *obj.Prog {
	// 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, p)
	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

	// MOVD	LR, R5
	p = obj.Appendp(ctxt, pcdata)
	pPre.Pcond = 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 pPreempt != nil {
		pPreempt.Pcond = p
	}

	// BL	runtime.morestack(SB)
	p = obj.Appendp(ctxt, p)

	p.As = ABL
	p.To.Type = obj.TYPE_BRANCH
	if ctxt.Cursym.Cfunc {
		p.To.Sym = obj.Linklookup(ctxt, "runtime.morestackc", 0)
	} else if ctxt.Cursym.Text.From3.Offset&obj.NEEDCTXT == 0 {
		p.To.Sym = obj.Linklookup(ctxt, "runtime.morestack_noctxt", 0)
	} else {
		p.To.Sym = obj.Linklookup(ctxt, "runtime.morestack", 0)
	}

	// BR	start
	p = obj.Appendp(ctxt, p)

	p.As = ABR
	p.To.Type = obj.TYPE_BRANCH
	p.Pcond = ctxt.Cursym.Text.Link
	return p
}
Ejemplo n.º 5
0
func outgcode(a int, g1 *obj.Addr, reg int, g2, g3 *obj.Addr) {
	var p *obj.Prog
	var pl *obj.Plist

	if asm.Pass == 1 {
		goto out
	}

	p = asm.Ctxt.NewProg()
	p.As = int16(a)
	p.Lineno = stmtline
	if nosched != 0 {
		p.Mark |= ppc64.NOSCHED
	}
	p.From = *g1
	p.Reg = int16(reg)
	p.From3 = *g2
	p.To = *g3
	p.Pc = int64(asm.PC)

	if lastpc == nil {
		pl = obj.Linknewplist(asm.Ctxt)
		pl.Firstpc = p
	} else {
		lastpc.Link = p
	}
	lastpc = p

out:
	if a != obj.AGLOBL && a != obj.ADATA {
		asm.PC++
	}
}
Ejemplo n.º 6
0
Archivo: lex.go Proyecto: Ericean/go
func outcode(a int, g2 *Addr2) {
	var p *obj.Prog
	var pl *obj.Plist

	if asm.Pass == 1 {
		goto out
	}

	p = new(obj.Prog)
	*p = obj.Prog{}
	p.Ctxt = asm.Ctxt
	p.As = int16(a)
	p.Lineno = stmtline
	p.From = g2.from
	p.To = g2.to
	p.Pc = int64(asm.PC)

	if lastpc == nil {
		pl = obj.Linknewplist(asm.Ctxt)
		pl.Firstpc = p
	} else {

		lastpc.Link = p
	}
	lastpc = p

out:
	if a != obj.AGLOBL && a != obj.ADATA {
		asm.PC++
	}
}
Ejemplo n.º 7
0
Archivo: gsubr.go Proyecto: Ryezhang/go
func Prog(as int) *obj.Prog {
	var p *obj.Prog

	if as == obj.ADATA || as == obj.AGLOBL {
		if ddumped != 0 {
			Fatalf("already dumped data")
		}
		if dpc == nil {
			dpc = Ctxt.NewProg()
			dfirst = dpc
		}

		p = dpc
		dpc = Ctxt.NewProg()
		p.Link = dpc
	} else {
		p = Pc
		Pc = Ctxt.NewProg()
		Clearp(Pc)
		p.Link = Pc
	}

	if lineno == 0 {
		if Debug['K'] != 0 {
			Warn("prog: line 0")
		}
	}

	p.As = int16(as)
	p.Lineno = lineno
	return p
}
Ejemplo n.º 8
0
func rewriteToPcrel(ctxt *obj.Link, p *obj.Prog) {
	// RegTo2 is set on the instructions we insert here so they don't get
	// processed twice.
	if p.RegTo2 != 0 {
		return
	}
	if p.As == obj.ATEXT || p.As == obj.AFUNCDATA || p.As == obj.ACALL || p.As == obj.ARET || p.As == obj.AJMP {
		return
	}
	// Any Prog (aside from the above special cases) with an Addr with Name ==
	// NAME_EXTERN, NAME_STATIC or NAME_GOTREF has a CALL __x86.get_pc_thunk.cx
	// inserted before it.
	isName := func(a *obj.Addr) bool {
		if a.Sym == nil || (a.Type != obj.TYPE_MEM && a.Type != obj.TYPE_ADDR) || a.Reg != 0 {
			return false
		}
		if a.Sym.Type == obj.STLSBSS {
			return false
		}
		return a.Name == obj.NAME_EXTERN || a.Name == obj.NAME_STATIC || a.Name == obj.NAME_GOTREF
	}

	if isName(&p.From) && p.From.Type == obj.TYPE_ADDR {
		// Handle things like "MOVL $sym, (SP)" or "PUSHL $sym" by rewriting
		// to "MOVL $sym, CX; MOVL CX, (SP)" or "MOVL $sym, CX; PUSHL CX"
		// respectively.
		if p.To.Type != obj.TYPE_REG {
			q := obj.Appendp(ctxt, p)
			q.As = p.As
			q.From.Type = obj.TYPE_REG
			q.From.Reg = REG_CX
			q.To = p.To
			p.As = AMOVL
			p.To.Type = obj.TYPE_REG
			p.To.Reg = REG_CX
			p.To.Sym = nil
			p.To.Name = obj.NAME_NONE
		}
	}

	if !isName(&p.From) && !isName(&p.To) && (p.From3 == nil || !isName(p.From3)) {
		return
	}
	q := obj.Appendp(ctxt, p)
	q.RegTo2 = 1
	r := obj.Appendp(ctxt, q)
	r.RegTo2 = 1
	q.As = obj.ACALL
	q.To.Sym = obj.Linklookup(ctxt, "__x86.get_pc_thunk.cx", 0)
	q.To.Type = obj.TYPE_MEM
	q.To.Name = obj.NAME_EXTERN
	q.To.Sym.Local = true
	r.As = p.As
	r.Scond = p.Scond
	r.From = p.From
	r.From3 = p.From3
	r.Reg = p.Reg
	r.To = p.To
	obj.Nopout(p)
}
Ejemplo n.º 9
0
Archivo: obj6.go Proyecto: achanda/go
// Append code to p to load g into cx.
// Overwrites p with the first instruction (no first appendp).
// Overwriting p is unusual but it lets use this in both the
// prologue (caller must call appendp first) and in the epilogue.
// Returns last new instruction.
func load_g_cx(ctxt *obj.Link, p *obj.Prog) *obj.Prog {
	p.As = AMOVQ
	if ctxt.Arch.PtrSize == 4 {
		p.As = AMOVL
	}
	p.From.Type = obj.TYPE_MEM
	p.From.Reg = REG_TLS
	p.From.Offset = 0
	p.To.Type = obj.TYPE_REG
	p.To.Reg = REG_CX

	next := p.Link
	progedit(ctxt, p)
	for p.Link != next {
		p = p.Link
	}

	if p.From.Index == REG_TLS {
		p.From.Scale = 2
	}

	return p
}
Ejemplo n.º 10
0
Archivo: arm.go Proyecto: danny8002/go
// ARMConditionCodes handles the special condition code situation for the ARM.
// It returns a boolean to indicate success; failure means cond was unrecognized.
func ARMConditionCodes(prog *obj.Prog, cond string) bool {
	if cond == "" {
		return true
	}
	bits, ok := ParseARMCondition(cond)
	if !ok {
		return false
	}
	/* hack to make B.NE etc. work: turn it into the corresponding conditional */
	if prog.As == arm.AB {
		prog.As = int16(bcode[(bits^arm.C_SCOND_XOR)&0xf])
		bits = (bits &^ 0xf) | arm.C_SCOND_NONE
	}
	prog.Scond = bits
	return true
}
Ejemplo n.º 11
0
func Prog(as obj.As) *obj.Prog {
	var p *obj.Prog

	p = pc
	pc = Ctxt.NewProg()
	Clearp(pc)
	p.Link = pc

	if lineno == 0 && Debug['K'] != 0 {
		Warn("prog: line 0")
	}

	p.As = as
	p.Lineno = lineno
	return p
}
Ejemplo n.º 12
0
func outcode(a int, g1 *obj.Addr, reg int, g2 *obj.Addr) {
	var p *obj.Prog
	var pl *obj.Plist

	if asm.Pass == 1 {
		goto out
	}

	if g1.Scale != 0 {
		if reg != 0 || g2.Scale != 0 {
			yyerror("bad addressing modes")
		}
		reg = int(g1.Scale)
	} else if g2.Scale != 0 {
		if reg != 0 {
			yyerror("bad addressing modes")
		}
		reg = int(g2.Scale)
	}

	p = asm.Ctxt.NewProg()
	p.As = int16(a)
	p.Lineno = stmtline
	if nosched != 0 {
		p.Mark |= ppc64.NOSCHED
	}
	p.From = *g1
	p.Reg = int16(reg)
	p.To = *g2
	p.Pc = int64(asm.PC)

	if lastpc == nil {
		pl = obj.Linknewplist(asm.Ctxt)
		pl.Firstpc = p
	} else {
		lastpc.Link = p
	}
	lastpc = p

out:
	if a != obj.AGLOBL && a != obj.ADATA {
		asm.PC++
	}
}
Ejemplo n.º 13
0
Archivo: ggen.go Proyecto: arnold8/go
// Called after regopt and peep have run.
// Expand CHECKNIL pseudo-op into actual nil pointer check.
func expandchecks(firstp *obj.Prog) {
	var reg int
	var p1 *obj.Prog

	for p := firstp; p != nil; p = p.Link {
		if p.As != obj.ACHECKNIL {
			continue
		}
		if gc.Debug_checknil != 0 && p.Lineno > 1 { // p->lineno==1 in generated wrappers
			gc.Warnl(int(p.Lineno), "generated nil check")
		}
		if p.From.Type != obj.TYPE_REG {
			gc.Fatalf("invalid nil check %v", p)
		}
		reg = int(p.From.Reg)

		// check is
		//	CMP arg, $0
		//	MOV.EQ arg, 0(arg)
		p1 = gc.Ctxt.NewProg()

		gc.Clearp(p1)
		p1.Link = p.Link
		p.Link = p1
		p1.Lineno = p.Lineno
		p1.Pc = 9999
		p1.As = arm.AMOVW
		p1.From.Type = obj.TYPE_REG
		p1.From.Reg = int16(reg)
		p1.To.Type = obj.TYPE_MEM
		p1.To.Reg = int16(reg)
		p1.To.Offset = 0
		p1.Scond = arm.C_SCOND_EQ
		p.As = arm.ACMP
		p.From.Type = obj.TYPE_CONST
		p.From.Reg = 0
		p.From.Offset = 0
		p.Reg = int16(reg)
	}
}
Ejemplo n.º 14
0
// Called after regopt and peep have run.
// Expand CHECKNIL pseudo-op into actual nil pointer check.
func expandchecks(firstp *obj.Prog) {
	var p1 *obj.Prog

	for p := (*obj.Prog)(firstp); p != nil; p = p.Link {
		if gc.Debug_checknil != 0 && gc.Ctxt.Debugvlog != 0 {
			fmt.Printf("expandchecks: %v\n", p)
		}
		if p.As != obj.ACHECKNIL {
			continue
		}
		if gc.Debug_checknil != 0 && p.Lineno > 1 { // p->lineno==1 in generated wrappers
			gc.Warnl(int(p.Lineno), "generated nil check")
		}
		if p.From.Type != obj.TYPE_REG {
			gc.Fatalf("invalid nil check %v\n", p)
		}

		// check is
		//	CBNZ arg, 2(PC)
		//	MOVD ZR, 0(arg)
		p1 = gc.Ctxt.NewProg()
		gc.Clearp(p1)
		p1.Link = p.Link
		p.Link = p1
		p1.Lineno = p.Lineno
		p1.Pc = 9999

		p.As = arm64.ACBNZ
		p.To.Type = obj.TYPE_BRANCH
		p.To.Val = p1.Link

		// crash by write to memory address 0.
		p1.As = arm64.AMOVD
		p1.From.Type = obj.TYPE_REG
		p1.From.Reg = arm64.REGZERO
		p1.To.Type = obj.TYPE_MEM
		p1.To.Reg = p.From.Reg
		p1.To.Offset = 0
	}
}
Ejemplo n.º 15
0
Archivo: lex.go Proyecto: Ericean/go
func outcode(a, scond int32, g1 *obj.Addr, reg int32, g2 *obj.Addr) {
	var p *obj.Prog
	var pl *obj.Plist

	/* hack to make B.NE etc. work: turn it into the corresponding conditional */
	if a == arm.AB {
		a = int32(bcode[(scond^arm.C_SCOND_XOR)&0xf])
		scond = (scond &^ 0xf) | Always
	}

	if asm.Pass == 1 {
		goto out
	}

	p = new(obj.Prog)
	*p = obj.Prog{}
	p.Ctxt = asm.Ctxt
	p.As = int16(a)
	p.Lineno = stmtline
	p.Scond = uint8(scond)
	p.From = *g1
	p.Reg = int16(reg)
	p.To = *g2
	p.Pc = int64(asm.PC)

	if lastpc == nil {
		pl = obj.Linknewplist(asm.Ctxt)
		pl.Firstpc = p
	} else {
		lastpc.Link = p
	}
	lastpc = p

out:
	if a != obj.AGLOBL && a != obj.ADATA {
		asm.PC++
	}
}
Ejemplo n.º 16
0
Archivo: asm0.go Proyecto: danny8002/go
func span0(ctxt *obj.Link, cursym *obj.LSym) {
	p := cursym.Text
	if p == nil || p.Link == nil { // handle external functions and ELF section symbols
		return
	}
	ctxt.Cursym = cursym
	ctxt.Autosize = int32(p.To.Offset + 8)

	if oprange[AOR&obj.AMask].start == nil {
		buildop(ctxt)
	}

	c := int64(0)
	p.Pc = c

	var m int
	var o *Optab
	for p = p.Link; p != nil; p = p.Link {
		ctxt.Curp = p
		p.Pc = c
		o = oplook(ctxt, p)
		m = int(o.size)
		if m == 0 {
			if p.As != obj.ANOP && p.As != obj.AFUNCDATA && p.As != obj.APCDATA && p.As != obj.AUSEFIELD {
				ctxt.Diag("zero-width instruction\n%v", p)
			}
			continue
		}

		c += int64(m)
	}

	cursym.Size = c

	/*
	 * if any procedure is large enough to
	 * generate a large SBRA branch, then
	 * generate extra passes putting branches
	 * around jmps to fix. this is rare.
	 */
	bflag := 1

	var otxt int64
	var q *obj.Prog
	for bflag != 0 {
		if ctxt.Debugvlog != 0 {
			fmt.Fprintf(ctxt.Bso, "%5.2f span1\n", obj.Cputime())
		}
		bflag = 0
		c = 0
		for p = cursym.Text.Link; p != nil; p = p.Link {
			p.Pc = c
			o = oplook(ctxt, p)

			// very large conditional branches
			if o.type_ == 6 && p.Pcond != nil {
				otxt = p.Pcond.Pc - c
				if otxt < -(1<<17)+10 || otxt >= (1<<17)-10 {
					q = ctxt.NewProg()
					q.Link = p.Link
					p.Link = q
					q.As = AJMP
					q.Lineno = p.Lineno
					q.To.Type = obj.TYPE_BRANCH
					q.Pcond = p.Pcond
					p.Pcond = q
					q = ctxt.NewProg()
					q.Link = p.Link
					p.Link = q
					q.As = AJMP
					q.Lineno = p.Lineno
					q.To.Type = obj.TYPE_BRANCH
					q.Pcond = q.Link.Link

					addnop(ctxt, p.Link)
					addnop(ctxt, p)
					bflag = 1
				}
			}

			m = int(o.size)
			if m == 0 {
				if p.As != obj.ANOP && p.As != obj.AFUNCDATA && p.As != obj.APCDATA && p.As != obj.AUSEFIELD {
					ctxt.Diag("zero-width instruction\n%v", p)
				}
				continue
			}

			c += int64(m)
		}

		cursym.Size = c
	}

	c += -c & (FuncAlign - 1)
	cursym.Size = c

	/*
	 * lay out the code, emitting code and data relocations.
	 */

	obj.Symgrow(ctxt, cursym, cursym.Size)

	bp := cursym.P
	var i int32
	var out [4]uint32
	for p := cursym.Text.Link; p != nil; p = p.Link {
		ctxt.Pc = p.Pc
		ctxt.Curp = p
		o = oplook(ctxt, p)
		if int(o.size) > 4*len(out) {
			log.Fatalf("out array in span0 is too small, need at least %d for %v", o.size/4, p)
		}
		asmout(ctxt, p, o, out[:])
		for i = 0; i < int32(o.size/4); i++ {
			ctxt.Arch.ByteOrder.PutUint32(bp, out[i])
			bp = bp[4:]
		}
	}
}
Ejemplo n.º 17
0
Archivo: peep.go Proyecto: hurkgu/go
func peep(firstp *obj.Prog) {
	g := gc.Flowstart(firstp, nil)
	if g == nil {
		return
	}
	gactive = 0

	var p *obj.Prog
	var r *gc.Flow
	var t obj.As
loop1:
	if gc.Debug['P'] != 0 && gc.Debug['v'] != 0 {
		gc.Dumpit("loop1", g.Start, 0)
	}

	t = 0
	for r = g.Start; r != nil; r = r.Link {
		p = r.Prog

		// TODO(austin) Handle smaller moves.  arm and amd64
		// distinguish between moves that moves that *must*
		// sign/zero extend and moves that don't care so they
		// can eliminate moves that don't care without
		// breaking moves that do care. This might let us
		// simplify or remove the next peep loop, too.
		if p.As == ppc64.AMOVD || p.As == ppc64.AFMOVD {
			if regtyp(&p.To) {
				// Try to eliminate reg->reg moves
				if regtyp(&p.From) {
					if p.From.Type == p.To.Type {
						if copyprop(r) {
							excise(r)
							t++
						} else if subprop(r) && copyprop(r) {
							excise(r)
							t++
						}
					}
				}

				// Convert uses to $0 to uses of R0 and
				// propagate R0
				if regzer(&p.From) {
					if p.To.Type == obj.TYPE_REG {
						p.From.Type = obj.TYPE_REG
						p.From.Reg = ppc64.REGZERO
						if copyprop(r) {
							excise(r)
							t++
						} else if subprop(r) && copyprop(r) {
							excise(r)
							t++
						}
					}
				}
			}
		}
	}

	if t != 0 {
		goto loop1
	}

	/*
	 * look for MOVB x,R; MOVB R,R (for small MOVs not handled above)
	 */
	var p1 *obj.Prog
	var r1 *gc.Flow
	for r := g.Start; r != nil; r = r.Link {
		p = r.Prog
		switch p.As {
		default:
			continue

		case ppc64.AMOVH,
			ppc64.AMOVHZ,
			ppc64.AMOVB,
			ppc64.AMOVBZ,
			ppc64.AMOVW,
			ppc64.AMOVWZ:
			if p.To.Type != obj.TYPE_REG {
				continue
			}
		}

		r1 = r.Link
		if r1 == nil {
			continue
		}
		p1 = r1.Prog
		if p1.As != p.As {
			continue
		}
		if p1.From.Type != obj.TYPE_REG || p1.From.Reg != p.To.Reg {
			continue
		}
		if p1.To.Type != obj.TYPE_REG || p1.To.Reg != p.To.Reg {
			continue
		}
		excise(r1)
	}

	if gc.Debug['D'] > 1 {
		goto ret /* allow following code improvement to be suppressed */
	}

	/*
	 * look for OP x,y,R; CMP R, $0 -> OPCC x,y,R
	 * when OP can set condition codes correctly
	 */
	for r := g.Start; r != nil; r = r.Link {
		p = r.Prog
		switch p.As {
		case ppc64.ACMP,
			ppc64.ACMPW: /* always safe? */
			if !regzer(&p.To) {
				continue
			}
			r1 = r.S1
			if r1 == nil {
				continue
			}
			switch r1.Prog.As {
			default:
				continue

				/* the conditions can be complex and these are currently little used */
			case ppc64.ABCL,
				ppc64.ABC:
				continue

			case ppc64.ABEQ,
				ppc64.ABGE,
				ppc64.ABGT,
				ppc64.ABLE,
				ppc64.ABLT,
				ppc64.ABNE,
				ppc64.ABVC,
				ppc64.ABVS:
				break
			}

			r1 = r
			for {
				r1 = gc.Uniqp(r1)
				if r1 == nil || r1.Prog.As != obj.ANOP {
					break
				}
			}

			if r1 == nil {
				continue
			}
			p1 = r1.Prog
			if p1.To.Type != obj.TYPE_REG || p1.To.Reg != p.From.Reg {
				continue
			}
			switch p1.As {
			/* irregular instructions */
			case ppc64.ASUB,
				ppc64.AADD,
				ppc64.AXOR,
				ppc64.AOR:
				if p1.From.Type == obj.TYPE_CONST || p1.From.Type == obj.TYPE_ADDR {
					continue
				}
			}

			switch p1.As {
			default:
				continue

			case ppc64.AMOVW,
				ppc64.AMOVD:
				if p1.From.Type != obj.TYPE_REG {
					continue
				}
				continue

			case ppc64.AANDCC,
				ppc64.AANDNCC,
				ppc64.AORCC,
				ppc64.AORNCC,
				ppc64.AXORCC,
				ppc64.ASUBCC,
				ppc64.ASUBECC,
				ppc64.ASUBMECC,
				ppc64.ASUBZECC,
				ppc64.AADDCC,
				ppc64.AADDCCC,
				ppc64.AADDECC,
				ppc64.AADDMECC,
				ppc64.AADDZECC,
				ppc64.ARLWMICC,
				ppc64.ARLWNMCC,
				/* don't deal with floating point instructions for now */
				/*
					case AFABS:
					case AFADD:
					case AFADDS:
					case AFCTIW:
					case AFCTIWZ:
					case AFDIV:
					case AFDIVS:
					case AFMADD:
					case AFMADDS:
					case AFMOVD:
					case AFMSUB:
					case AFMSUBS:
					case AFMUL:
					case AFMULS:
					case AFNABS:
					case AFNEG:
					case AFNMADD:
					case AFNMADDS:
					case AFNMSUB:
					case AFNMSUBS:
					case AFRSP:
					case AFSUB:
					case AFSUBS:
					case ACNTLZW:
					case AMTFSB0:
					case AMTFSB1:
				*/
				ppc64.AADD,
				ppc64.AADDV,
				ppc64.AADDC,
				ppc64.AADDCV,
				ppc64.AADDME,
				ppc64.AADDMEV,
				ppc64.AADDE,
				ppc64.AADDEV,
				ppc64.AADDZE,
				ppc64.AADDZEV,
				ppc64.AAND,
				ppc64.AANDN,
				ppc64.ADIVW,
				ppc64.ADIVWV,
				ppc64.ADIVWU,
				ppc64.ADIVWUV,
				ppc64.ADIVD,
				ppc64.ADIVDV,
				ppc64.ADIVDU,
				ppc64.ADIVDUV,
				ppc64.AEQV,
				ppc64.AEXTSB,
				ppc64.AEXTSH,
				ppc64.AEXTSW,
				ppc64.AMULHW,
				ppc64.AMULHWU,
				ppc64.AMULLW,
				ppc64.AMULLWV,
				ppc64.AMULHD,
				ppc64.AMULHDU,
				ppc64.AMULLD,
				ppc64.AMULLDV,
				ppc64.ANAND,
				ppc64.ANEG,
				ppc64.ANEGV,
				ppc64.ANOR,
				ppc64.AOR,
				ppc64.AORN,
				ppc64.AREM,
				ppc64.AREMV,
				ppc64.AREMU,
				ppc64.AREMUV,
				ppc64.AREMD,
				ppc64.AREMDV,
				ppc64.AREMDU,
				ppc64.AREMDUV,
				ppc64.ARLWMI,
				ppc64.ARLWNM,
				ppc64.ASLW,
				ppc64.ASRAW,
				ppc64.ASRW,
				ppc64.ASLD,
				ppc64.ASRAD,
				ppc64.ASRD,
				ppc64.ASUB,
				ppc64.ASUBV,
				ppc64.ASUBC,
				ppc64.ASUBCV,
				ppc64.ASUBME,
				ppc64.ASUBMEV,
				ppc64.ASUBE,
				ppc64.ASUBEV,
				ppc64.ASUBZE,
				ppc64.ASUBZEV,
				ppc64.AXOR:
				t = variant2as(p1.As, as2variant(p1.As)|V_CC)
			}

			if gc.Debug['D'] != 0 {
				fmt.Printf("cmp %v; %v -> ", p1, p)
			}
			p1.As = t
			if gc.Debug['D'] != 0 {
				fmt.Printf("%v\n", p1)
			}
			excise(r)
			continue
		}
	}

ret:
	gc.Flowend(g)
}
Ejemplo n.º 18
0
Archivo: ggen.go Proyecto: Ericean/go
// Called after regopt and peep have run.
// Expand CHECKNIL pseudo-op into actual nil pointer check.
func expandchecks(firstp *obj.Prog) {
	var p1 *obj.Prog
	var p2 *obj.Prog

	for p := (*obj.Prog)(firstp); p != nil; p = p.Link {
		if gc.Debug_checknil != 0 && gc.Ctxt.Debugvlog != 0 {
			fmt.Printf("expandchecks: %v\n", p)
		}
		if p.As != obj.ACHECKNIL {
			continue
		}
		if gc.Debug_checknil != 0 && p.Lineno > 1 { // p->lineno==1 in generated wrappers
			gc.Warnl(int(p.Lineno), "generated nil check")
		}
		if p.From.Type != obj.TYPE_REG {
			gc.Fatal("invalid nil check %v\n", p)
		}

		/*
			// check is
			//	TD $4, R0, arg (R0 is always zero)
			// eqv. to:
			// 	tdeq r0, arg
			// NOTE: this needs special runtime support to make SIGTRAP recoverable.
			reg = p->from.reg;
			p->as = ATD;
			p->from = p->to = p->from3 = zprog.from;
			p->from.type = TYPE_CONST;
			p->from.offset = 4;
			p->from.reg = 0;
			p->reg = REGZERO;
			p->to.type = TYPE_REG;
			p->to.reg = reg;
		*/
		// check is
		//	CMP arg, R0
		//	BNE 2(PC) [likely]
		//	MOVD R0, 0(R0)
		p1 = gc.Ctxt.NewProg()

		p2 = gc.Ctxt.NewProg()
		gc.Clearp(p1)
		gc.Clearp(p2)
		p1.Link = p2
		p2.Link = p.Link
		p.Link = p1
		p1.Lineno = p.Lineno
		p2.Lineno = p.Lineno
		p1.Pc = 9999
		p2.Pc = 9999
		p.As = ppc64.ACMP
		p.To.Type = obj.TYPE_REG
		p.To.Reg = ppc64.REGZERO
		p1.As = ppc64.ABNE

		//p1->from.type = TYPE_CONST;
		//p1->from.offset = 1; // likely
		p1.To.Type = obj.TYPE_BRANCH

		p1.To.Val = p2.Link

		// crash by write to memory address 0.
		p2.As = ppc64.AMOVD

		p2.From.Type = obj.TYPE_REG
		p2.From.Reg = ppc64.REGZERO
		p2.To.Type = obj.TYPE_MEM
		p2.To.Reg = ppc64.REGZERO
		p2.To.Offset = 0
	}
}
Ejemplo n.º 19
0
/*
 * ASLL x,y,w
 * .. (not use w, not set x y w)
 * AXXX w,a,b (a != w)
 * .. (not use w)
 * (set w)
 * ----------- changed to
 * ..
 * AXXX (x<<y),a,b
 * ..
 */
func shiftprop(r *gc.Flow) bool {
	p := (*obj.Prog)(r.Prog)
	if p.To.Type != obj.TYPE_REG {
		if gc.Debug['P'] != 0 {
			fmt.Printf("\tBOTCH: result not reg; FAILURE\n")
		}
		return false
	}

	n := int(int(p.To.Reg))
	a := obj.Addr(obj.Addr{})
	if p.Reg != 0 && p.Reg != p.To.Reg {
		a.Type = obj.TYPE_REG
		a.Reg = p.Reg
	}

	if gc.Debug['P'] != 0 {
		fmt.Printf("shiftprop\n%v", p)
	}
	r1 := (*gc.Flow)(r)
	var p1 *obj.Prog
	for {
		/* find first use of shift result; abort if shift operands or result are changed */
		r1 = gc.Uniqs(r1)

		if r1 == nil {
			if gc.Debug['P'] != 0 {
				fmt.Printf("\tbranch; FAILURE\n")
			}
			return false
		}

		if gc.Uniqp(r1) == nil {
			if gc.Debug['P'] != 0 {
				fmt.Printf("\tmerge; FAILURE\n")
			}
			return false
		}

		p1 = r1.Prog
		if gc.Debug['P'] != 0 {
			fmt.Printf("\n%v", p1)
		}
		switch copyu(p1, &p.To, nil) {
		case 0: /* not used or set */
			if (p.From.Type == obj.TYPE_REG && copyu(p1, &p.From, nil) > 1) || (a.Type == obj.TYPE_REG && copyu(p1, &a, nil) > 1) {
				if gc.Debug['P'] != 0 {
					fmt.Printf("\targs modified; FAILURE\n")
				}
				return false
			}

			continue
		case 3: /* set, not used */
			{
				if gc.Debug['P'] != 0 {
					fmt.Printf("\tBOTCH: noref; FAILURE\n")
				}
				return false
			}
		}

		break
	}

	/* check whether substitution can be done */
	switch p1.As {
	default:
		if gc.Debug['P'] != 0 {
			fmt.Printf("\tnon-dpi; FAILURE\n")
		}
		return false

	case arm.AAND,
		arm.AEOR,
		arm.AADD,
		arm.AADC,
		arm.AORR,
		arm.ASUB,
		arm.ASBC,
		arm.ARSB,
		arm.ARSC:
		if int(p1.Reg) == n || (p1.Reg == 0 && p1.To.Type == obj.TYPE_REG && int(p1.To.Reg) == n) {
			if p1.From.Type != obj.TYPE_REG {
				if gc.Debug['P'] != 0 {
					fmt.Printf("\tcan't swap; FAILURE\n")
				}
				return false
			}

			p1.Reg = p1.From.Reg
			p1.From.Reg = int16(n)
			switch p1.As {
			case arm.ASUB:
				p1.As = arm.ARSB

			case arm.ARSB:
				p1.As = arm.ASUB

			case arm.ASBC:
				p1.As = arm.ARSC

			case arm.ARSC:
				p1.As = arm.ASBC
			}

			if gc.Debug['P'] != 0 {
				fmt.Printf("\t=>%v", p1)
			}
		}
		fallthrough

	case arm.ABIC,
		arm.ATST,
		arm.ACMP,
		arm.ACMN:
		if int(p1.Reg) == n {
			if gc.Debug['P'] != 0 {
				fmt.Printf("\tcan't swap; FAILURE\n")
			}
			return false
		}

		if p1.Reg == 0 && int(p1.To.Reg) == n {
			if gc.Debug['P'] != 0 {
				fmt.Printf("\tshift result used twice; FAILURE\n")
			}
			return false
		}

		//	case AMVN:
		if p1.From.Type == obj.TYPE_SHIFT {
			if gc.Debug['P'] != 0 {
				fmt.Printf("\tshift result used in shift; FAILURE\n")
			}
			return false
		}

		if p1.From.Type != obj.TYPE_REG || int(p1.From.Reg) != n {
			if gc.Debug['P'] != 0 {
				fmt.Printf("\tBOTCH: where is it used?; FAILURE\n")
			}
			return false
		}
	}

	/* check whether shift result is used subsequently */
	p2 := (*obj.Prog)(p1)

	if int(p1.To.Reg) != n {
		var p1 *obj.Prog
		for {
			r1 = gc.Uniqs(r1)
			if r1 == nil {
				if gc.Debug['P'] != 0 {
					fmt.Printf("\tinconclusive; FAILURE\n")
				}
				return false
			}

			p1 = r1.Prog
			if gc.Debug['P'] != 0 {
				fmt.Printf("\n%v", p1)
			}
			switch copyu(p1, &p.To, nil) {
			case 0: /* not used or set */
				continue

			case 3: /* set, not used */
				break

			default: /* used */
				if gc.Debug['P'] != 0 {
					fmt.Printf("\treused; FAILURE\n")
				}
				return false
			}

			break
		}
	}

	/* make the substitution */
	p2.From.Reg = 0

	o := int(int(p.Reg))
	if o == 0 {
		o = int(p.To.Reg)
	}
	o &= 15

	switch p.From.Type {
	case obj.TYPE_CONST:
		o |= int((p.From.Offset & 0x1f) << 7)

	case obj.TYPE_REG:
		o |= 1<<4 | (int(p.From.Reg)&15)<<8
	}

	switch p.As {
	case arm.ASLL:
		o |= 0 << 5

	case arm.ASRL:
		o |= 1 << 5

	case arm.ASRA:
		o |= 2 << 5
	}

	p2.From = obj.Addr{}
	p2.From.Type = obj.TYPE_SHIFT
	p2.From.Offset = int64(o)
	if gc.Debug['P'] != 0 {
		fmt.Printf("\t=>%v\tSUCCEED\n", p2)
	}
	return true
}
Ejemplo n.º 20
0
// UNUSED
func peep(firstp *obj.Prog) {
	g := (*gc.Graph)(gc.Flowstart(firstp, nil))
	if g == nil {
		return
	}
	gactive = 0

	var r *gc.Flow
	var p *obj.Prog
	var t int
loop1:
	if gc.Debug['P'] != 0 && gc.Debug['v'] != 0 {
		gc.Dumpit("loop1", g.Start, 0)
	}

	t = 0
	for r = g.Start; r != nil; r = r.Link {
		p = r.Prog
		switch p.As {
		/*
		 * elide shift into TYPE_SHIFT operand of subsequent instruction
		 */
		//			if(shiftprop(r)) {
		//				excise(r);
		//				t++;
		//				break;
		//			}
		case arm.ASLL,
			arm.ASRL,
			arm.ASRA:
			break

		case arm.AMOVB,
			arm.AMOVH,
			arm.AMOVW,
			arm.AMOVF,
			arm.AMOVD:
			if regtyp(&p.From) {
				if p.From.Type == p.To.Type && isfloatreg(&p.From) == isfloatreg(&p.To) {
					if p.Scond == arm.C_SCOND_NONE {
						if copyprop(g, r) {
							excise(r)
							t++
							break
						}

						if subprop(r) && copyprop(g, r) {
							excise(r)
							t++
							break
						}
					}
				}
			}

		case arm.AMOVHS,
			arm.AMOVHU,
			arm.AMOVBS,
			arm.AMOVBU:
			if p.From.Type == obj.TYPE_REG {
				if shortprop(r) {
					t++
				}
			}
		}
	}

	/*
		if(p->scond == C_SCOND_NONE)
		if(regtyp(&p->to))
		if(isdconst(&p->from)) {
			constprop(&p->from, &p->to, r->s1);
		}
		break;
	*/
	if t != 0 {
		goto loop1
	}

	for r := (*gc.Flow)(g.Start); r != nil; r = r.Link {
		p = r.Prog
		switch p.As {
		/*
		 * EOR -1,x,y => MVN x,y
		 */
		case arm.AEOR:
			if isdconst(&p.From) && p.From.Offset == -1 {
				p.As = arm.AMVN
				p.From.Type = obj.TYPE_REG
				if p.Reg != 0 {
					p.From.Reg = p.Reg
				} else {
					p.From.Reg = p.To.Reg
				}
				p.Reg = 0
			}
		}
	}

	for r := (*gc.Flow)(g.Start); r != nil; r = r.Link {
		p = r.Prog
		switch p.As {
		case arm.AMOVW,
			arm.AMOVB,
			arm.AMOVBS,
			arm.AMOVBU:
			if p.From.Type == obj.TYPE_MEM && p.From.Offset == 0 {
				xtramodes(g, r, &p.From)
			} else if p.To.Type == obj.TYPE_MEM && p.To.Offset == 0 {
				xtramodes(g, r, &p.To)
			} else {
				continue
			}
		}
	}

	//		case ACMP:
	//			/*
	//			 * elide CMP $0,x if calculation of x can set condition codes
	//			 */
	//			if(isdconst(&p->from) || p->from.offset != 0)
	//				continue;
	//			r2 = r->s1;
	//			if(r2 == nil)
	//				continue;
	//			t = r2->prog->as;
	//			switch(t) {
	//			default:
	//				continue;
	//			case ABEQ:
	//			case ABNE:
	//			case ABMI:
	//			case ABPL:
	//				break;
	//			case ABGE:
	//				t = ABPL;
	//				break;
	//			case ABLT:
	//				t = ABMI;
	//				break;
	//			case ABHI:
	//				t = ABNE;
	//				break;
	//			case ABLS:
	//				t = ABEQ;
	//				break;
	//			}
	//			r1 = r;
	//			do
	//				r1 = uniqp(r1);
	//			while (r1 != nil && r1->prog->as == ANOP);
	//			if(r1 == nil)
	//				continue;
	//			p1 = r1->prog;
	//			if(p1->to.type != TYPE_REG)
	//				continue;
	//			if(p1->to.reg != p->reg)
	//			if(!(p1->as == AMOVW && p1->from.type == TYPE_REG && p1->from.reg == p->reg))
	//				continue;
	//
	//			switch(p1->as) {
	//			default:
	//				continue;
	//			case AMOVW:
	//				if(p1->from.type != TYPE_REG)
	//					continue;
	//			case AAND:
	//			case AEOR:
	//			case AORR:
	//			case ABIC:
	//			case AMVN:
	//			case ASUB:
	//			case ARSB:
	//			case AADD:
	//			case AADC:
	//			case ASBC:
	//			case ARSC:
	//				break;
	//			}
	//			p1->scond |= C_SBIT;
	//			r2->prog->as = t;
	//			excise(r);
	//			continue;

	//	predicate(g);

	gc.Flowend(g)
}
Ejemplo n.º 21
0
Archivo: obj5.go Proyecto: arnold8/go
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 != 0 {
		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 {
	}

	// MOVW	LR, R3
	movw := obj.Appendp(ctxt, last)
	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 != 0:
		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

	return bls
}
Ejemplo n.º 22
0
Archivo: gsubr.go Proyecto: Ryezhang/go
func Clearp(p *obj.Prog) {
	obj.Nopout(p)
	p.As = obj.AEND
	p.Pc = int64(pcloc)
	pcloc++
}
Ejemplo n.º 23
0
// movb elimination.
// movb is simulated by the linker
// when a register other than ax, bx, cx, dx
// is used, so rewrite to other instructions
// when possible.  a movb into a register
// can smash the entire 64-bit register without
// causing any trouble.
func elimshortmov(g *gc.Graph) {
	var p *obj.Prog

	for r := g.Start; r != nil; r = r.Link {
		p = r.Prog
		if regtyp(&p.To) {
			switch p.As {
			case x86.AINCB,
				x86.AINCW:
				p.As = x86.AINCL

			case x86.ADECB,
				x86.ADECW:
				p.As = x86.ADECL

			case x86.ANEGB,
				x86.ANEGW:
				p.As = x86.ANEGL

			case x86.ANOTB,
				x86.ANOTW:
				p.As = x86.ANOTL
			}

			if regtyp(&p.From) || p.From.Type == obj.TYPE_CONST {
				// move or artihmetic into partial register.
				// from another register or constant can be movl.
				// we don't switch to 32-bit arithmetic if it can
				// change how the carry bit is set (and the carry bit is needed).
				switch p.As {
				case x86.AMOVB,
					x86.AMOVW:
					p.As = x86.AMOVL

				case x86.AADDB,
					x86.AADDW:
					if !needc(p.Link) {
						p.As = x86.AADDL
					}

				case x86.ASUBB,
					x86.ASUBW:
					if !needc(p.Link) {
						p.As = x86.ASUBL
					}

				case x86.AMULB,
					x86.AMULW:
					p.As = x86.AMULL

				case x86.AIMULB,
					x86.AIMULW:
					p.As = x86.AIMULL

				case x86.AANDB,
					x86.AANDW:
					p.As = x86.AANDL

				case x86.AORB,
					x86.AORW:
					p.As = x86.AORL

				case x86.AXORB,
					x86.AXORW:
					p.As = x86.AXORL

				case x86.ASHLB,
					x86.ASHLW:
					p.As = x86.ASHLL
				}
			} else {
				// explicit zero extension
				switch p.As {
				case x86.AMOVB:
					p.As = x86.AMOVBLZX

				case x86.AMOVW:
					p.As = x86.AMOVWLZX
				}
			}
		}
	}
}
Ejemplo n.º 24
0
Archivo: obj5.go Proyecto: arnold8/go
func xfol(ctxt *obj.Link, p *obj.Prog, last **obj.Prog) {
	var q *obj.Prog
	var r *obj.Prog
	var a int
	var i int

loop:
	if p == nil {
		return
	}
	a = int(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 = int(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 = int16(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 = int16(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
}
Ejemplo n.º 25
0
func preprocess(ctxt *obj.Link, cursym *obj.LSym) {
	if ctxt.Headtype == obj.Hplan9 && ctxt.Plan9privates == nil {
		ctxt.Plan9privates = obj.Linklookup(ctxt, "_privates", 0)
	}

	ctxt.Cursym = cursym

	if cursym.Text == nil || cursym.Text.Link == nil {
		return
	}

	p := cursym.Text
	autoffset := int32(p.To.Offset)
	if autoffset < 0 {
		autoffset = 0
	}

	var bpsize int
	if p.Mode == 64 && obj.Framepointer_enabled != 0 && autoffset > 0 {
		// Make room for to save a base pointer. If autoffset == 0,
		// this might do something special like a tail jump to
		// another function, so in that case we omit this.
		bpsize = ctxt.Arch.Ptrsize

		autoffset += int32(bpsize)
		p.To.Offset += int64(bpsize)
	} else {
		bpsize = 0
	}

	textarg := int64(p.To.Val.(int32))
	cursym.Args = int32(textarg)
	cursym.Locals = int32(p.To.Offset)

	// TODO(rsc): Remove.
	if p.Mode == 32 && cursym.Locals < 0 {
		cursym.Locals = 0
	}

	// TODO(rsc): Remove 'p.Mode == 64 &&'.
	if p.Mode == 64 && autoffset < obj.StackSmall && p.From3Offset()&obj.NOSPLIT == 0 {
		for q := p; q != nil; q = q.Link {
			if q.As == obj.ACALL {
				goto noleaf
			}
			if (q.As == obj.ADUFFCOPY || q.As == obj.ADUFFZERO) && autoffset >= obj.StackSmall-8 {
				goto noleaf
			}
		}

		p.From3.Offset |= obj.NOSPLIT
	noleaf:
	}

	if p.From3Offset()&obj.NOSPLIT == 0 || p.From3Offset()&obj.WRAPPER != 0 {
		p = obj.Appendp(ctxt, p)
		p = load_g_cx(ctxt, p) // load g into CX
	}

	if cursym.Text.From3Offset()&obj.NOSPLIT == 0 {
		p = stacksplit(ctxt, p, autoffset, int32(textarg)) // emit split check
	}

	if autoffset != 0 {
		if autoffset%int32(ctxt.Arch.Regsize) != 0 {
			ctxt.Diag("unaligned stack size %d", autoffset)
		}
		p = obj.Appendp(ctxt, p)
		p.As = AADJSP
		p.From.Type = obj.TYPE_CONST
		p.From.Offset = int64(autoffset)
		p.Spadj = autoffset
	} else {
		// zero-byte stack adjustment.
		// Insert a fake non-zero adjustment so that stkcheck can
		// recognize the end of the stack-splitting prolog.
		p = obj.Appendp(ctxt, p)

		p.As = obj.ANOP
		p.Spadj = int32(-ctxt.Arch.Ptrsize)
		p = obj.Appendp(ctxt, p)
		p.As = obj.ANOP
		p.Spadj = int32(ctxt.Arch.Ptrsize)
	}

	deltasp := autoffset

	if bpsize > 0 {
		// Save caller's BP
		p = obj.Appendp(ctxt, p)

		p.As = AMOVQ
		p.From.Type = obj.TYPE_REG
		p.From.Reg = REG_BP
		p.To.Type = obj.TYPE_MEM
		p.To.Reg = REG_SP
		p.To.Scale = 1
		p.To.Offset = int64(autoffset) - int64(bpsize)

		// Move current frame to BP
		p = obj.Appendp(ctxt, p)

		p.As = ALEAQ
		p.From.Type = obj.TYPE_MEM
		p.From.Reg = REG_SP
		p.From.Scale = 1
		p.From.Offset = int64(autoffset) - int64(bpsize)
		p.To.Type = obj.TYPE_REG
		p.To.Reg = REG_BP
	}

	if cursym.Text.From3Offset()&obj.WRAPPER != 0 {
		// if(g->panic != nil && g->panic->argp == FP) g->panic->argp = bottom-of-frame
		//
		//	MOVQ g_panic(CX), BX
		//	TESTQ BX, BX
		//	JEQ end
		//	LEAQ (autoffset+8)(SP), DI
		//	CMPQ panic_argp(BX), DI
		//	JNE end
		//	MOVQ SP, panic_argp(BX)
		// end:
		//	NOP
		//
		// The NOP is needed to give the jumps somewhere to land.
		// It is a liblink NOP, not an x86 NOP: it encodes to 0 instruction bytes.

		p = obj.Appendp(ctxt, p)

		p.As = AMOVQ
		p.From.Type = obj.TYPE_MEM
		p.From.Reg = REG_CX
		p.From.Offset = 4 * int64(ctxt.Arch.Ptrsize) // G.panic
		p.To.Type = obj.TYPE_REG
		p.To.Reg = REG_BX
		if ctxt.Headtype == obj.Hnacl && p.Mode == 64 {
			p.As = AMOVL
			p.From.Type = obj.TYPE_MEM
			p.From.Reg = REG_R15
			p.From.Scale = 1
			p.From.Index = REG_CX
		}
		if p.Mode == 32 {
			p.As = AMOVL
		}

		p = obj.Appendp(ctxt, p)
		p.As = ATESTQ
		p.From.Type = obj.TYPE_REG
		p.From.Reg = REG_BX
		p.To.Type = obj.TYPE_REG
		p.To.Reg = REG_BX
		if ctxt.Headtype == obj.Hnacl || p.Mode == 32 {
			p.As = ATESTL
		}

		p = obj.Appendp(ctxt, p)
		p.As = AJEQ
		p.To.Type = obj.TYPE_BRANCH
		p1 := p

		p = obj.Appendp(ctxt, p)
		p.As = ALEAQ
		p.From.Type = obj.TYPE_MEM
		p.From.Reg = REG_SP
		p.From.Offset = int64(autoffset) + int64(ctxt.Arch.Regsize)
		p.To.Type = obj.TYPE_REG
		p.To.Reg = REG_DI
		if ctxt.Headtype == obj.Hnacl || p.Mode == 32 {
			p.As = ALEAL
		}

		p = obj.Appendp(ctxt, p)
		p.As = ACMPQ
		p.From.Type = obj.TYPE_MEM
		p.From.Reg = REG_BX
		p.From.Offset = 0 // Panic.argp
		p.To.Type = obj.TYPE_REG
		p.To.Reg = REG_DI
		if ctxt.Headtype == obj.Hnacl && p.Mode == 64 {
			p.As = ACMPL
			p.From.Type = obj.TYPE_MEM
			p.From.Reg = REG_R15
			p.From.Scale = 1
			p.From.Index = REG_BX
		}
		if p.Mode == 32 {
			p.As = ACMPL
		}

		p = obj.Appendp(ctxt, p)
		p.As = AJNE
		p.To.Type = obj.TYPE_BRANCH
		p2 := p

		p = obj.Appendp(ctxt, p)
		p.As = AMOVQ
		p.From.Type = obj.TYPE_REG
		p.From.Reg = REG_SP
		p.To.Type = obj.TYPE_MEM
		p.To.Reg = REG_BX
		p.To.Offset = 0 // Panic.argp
		if ctxt.Headtype == obj.Hnacl && p.Mode == 64 {
			p.As = AMOVL
			p.To.Type = obj.TYPE_MEM
			p.To.Reg = REG_R15
			p.To.Scale = 1
			p.To.Index = REG_BX
		}
		if p.Mode == 32 {
			p.As = AMOVL
		}

		p = obj.Appendp(ctxt, p)
		p.As = obj.ANOP
		p1.Pcond = p
		p2.Pcond = p
	}

	var a int
	var pcsize int
	for ; p != nil; p = p.Link {
		pcsize = int(p.Mode) / 8
		a = int(p.From.Name)
		if a == obj.NAME_AUTO {
			p.From.Offset += int64(deltasp) - int64(bpsize)
		}
		if a == obj.NAME_PARAM {
			p.From.Offset += int64(deltasp) + int64(pcsize)
		}
		if p.From3 != nil {
			a = int(p.From3.Name)
			if a == obj.NAME_AUTO {
				p.From3.Offset += int64(deltasp) - int64(bpsize)
			}
			if a == obj.NAME_PARAM {
				p.From3.Offset += int64(deltasp) + int64(pcsize)
			}
		}
		a = int(p.To.Name)
		if a == obj.NAME_AUTO {
			p.To.Offset += int64(deltasp) - int64(bpsize)
		}
		if a == obj.NAME_PARAM {
			p.To.Offset += int64(deltasp) + int64(pcsize)
		}

		switch p.As {
		default:
			continue

		case APUSHL, APUSHFL:
			deltasp += 4
			p.Spadj = 4
			continue

		case APUSHQ, APUSHFQ:
			deltasp += 8
			p.Spadj = 8
			continue

		case APUSHW, APUSHFW:
			deltasp += 2
			p.Spadj = 2
			continue

		case APOPL, APOPFL:
			deltasp -= 4
			p.Spadj = -4
			continue

		case APOPQ, APOPFQ:
			deltasp -= 8
			p.Spadj = -8
			continue

		case APOPW, APOPFW:
			deltasp -= 2
			p.Spadj = -2
			continue

		case obj.ARET:
			break
		}

		if autoffset != deltasp {
			ctxt.Diag("unbalanced PUSH/POP")
		}

		if autoffset != 0 {
			if bpsize > 0 {
				// Restore caller's BP
				p.As = AMOVQ

				p.From.Type = obj.TYPE_MEM
				p.From.Reg = REG_SP
				p.From.Scale = 1
				p.From.Offset = int64(autoffset) - int64(bpsize)
				p.To.Type = obj.TYPE_REG
				p.To.Reg = REG_BP
				p = obj.Appendp(ctxt, p)
			}

			p.As = AADJSP
			p.From.Type = obj.TYPE_CONST
			p.From.Offset = int64(-autoffset)
			p.Spadj = -autoffset
			p = obj.Appendp(ctxt, p)
			p.As = obj.ARET

			// If there are instructions following
			// this ARET, they come from a branch
			// with the same stackframe, so undo
			// the cleanup.
			p.Spadj = +autoffset
		}

		if p.To.Sym != nil { // retjmp
			p.As = obj.AJMP
		}
	}
}

func indir_cx(ctxt *obj.Link, p *obj.Prog, a *obj.Addr) {
	if ctxt.Headtype == obj.Hnacl && p.Mode == 64 {
		a.Type = obj.TYPE_MEM
		a.Reg = REG_R15
		a.Index = REG_CX
		a.Scale = 1
		return
	}

	a.Type = obj.TYPE_MEM
	a.Reg = REG_CX
}

// Append code to p to load g into cx.
// Overwrites p with the first instruction (no first appendp).
// Overwriting p is unusual but it lets use this in both the
// prologue (caller must call appendp first) and in the epilogue.
// Returns last new instruction.
func load_g_cx(ctxt *obj.Link, p *obj.Prog) *obj.Prog {
	p.As = AMOVQ
	if ctxt.Arch.Ptrsize == 4 {
		p.As = AMOVL
	}
	p.From.Type = obj.TYPE_MEM
	p.From.Reg = REG_TLS
	p.From.Offset = 0
	p.To.Type = obj.TYPE_REG
	p.To.Reg = REG_CX

	next := p.Link
	progedit(ctxt, p)
	for p.Link != next {
		p = p.Link
	}

	if p.From.Index == REG_TLS {
		p.From.Scale = 2
	}

	return p
}

// Append code to p to check for stack split.
// Appends to (does not overwrite) p.
// Assumes g is in CX.
// Returns last new instruction.
func stacksplit(ctxt *obj.Link, p *obj.Prog, framesize int32, textarg int32) *obj.Prog {
	cmp := ACMPQ
	lea := ALEAQ
	mov := AMOVQ
	sub := ASUBQ

	if ctxt.Headtype == obj.Hnacl || p.Mode == 32 {
		cmp = ACMPL
		lea = ALEAL
		mov = AMOVL
		sub = ASUBL
	}

	var q1 *obj.Prog
	if framesize <= obj.StackSmall {
		// small stack: SP <= stackguard
		//	CMPQ SP, stackguard
		p = obj.Appendp(ctxt, p)

		p.As = cmp
		p.From.Type = obj.TYPE_REG
		p.From.Reg = REG_SP
		indir_cx(ctxt, p, &p.To)
		p.To.Offset = 2 * int64(ctxt.Arch.Ptrsize) // G.stackguard0
		if ctxt.Cursym.Cfunc {
			p.To.Offset = 3 * int64(ctxt.Arch.Ptrsize) // G.stackguard1
		}
	} else if framesize <= obj.StackBig {
		// large stack: SP-framesize <= stackguard-StackSmall
		//	LEAQ -xxx(SP), AX
		//	CMPQ AX, stackguard
		p = obj.Appendp(ctxt, p)

		p.As = lea
		p.From.Type = obj.TYPE_MEM
		p.From.Reg = REG_SP
		p.From.Offset = -(int64(framesize) - obj.StackSmall)
		p.To.Type = obj.TYPE_REG
		p.To.Reg = REG_AX

		p = obj.Appendp(ctxt, p)
		p.As = cmp
		p.From.Type = obj.TYPE_REG
		p.From.Reg = REG_AX
		indir_cx(ctxt, p, &p.To)
		p.To.Offset = 2 * int64(ctxt.Arch.Ptrsize) // G.stackguard0
		if ctxt.Cursym.Cfunc {
			p.To.Offset = 3 * int64(ctxt.Arch.Ptrsize) // G.stackguard1
		}
	} 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.
		//	MOVQ	stackguard, CX
		//	CMPQ	CX, $StackPreempt
		//	JEQ	label-of-call-to-morestack
		//	LEAQ	StackGuard(SP), AX
		//	SUBQ	CX, AX
		//	CMPQ	AX, $(framesize+(StackGuard-StackSmall))

		p = obj.Appendp(ctxt, p)

		p.As = mov
		indir_cx(ctxt, p, &p.From)
		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_SI

		p = obj.Appendp(ctxt, p)
		p.As = cmp
		p.From.Type = obj.TYPE_REG
		p.From.Reg = REG_SI
		p.To.Type = obj.TYPE_CONST
		p.To.Offset = obj.StackPreempt
		if p.Mode == 32 {
			p.To.Offset = int64(uint32(obj.StackPreempt & (1<<32 - 1)))
		}

		p = obj.Appendp(ctxt, p)
		p.As = AJEQ
		p.To.Type = obj.TYPE_BRANCH
		q1 = p

		p = obj.Appendp(ctxt, p)
		p.As = lea
		p.From.Type = obj.TYPE_MEM
		p.From.Reg = REG_SP
		p.From.Offset = obj.StackGuard
		p.To.Type = obj.TYPE_REG
		p.To.Reg = REG_AX

		p = obj.Appendp(ctxt, p)
		p.As = sub
		p.From.Type = obj.TYPE_REG
		p.From.Reg = REG_SI
		p.To.Type = obj.TYPE_REG
		p.To.Reg = REG_AX

		p = obj.Appendp(ctxt, p)
		p.As = cmp
		p.From.Type = obj.TYPE_REG
		p.From.Reg = REG_AX
		p.To.Type = obj.TYPE_CONST
		p.To.Offset = int64(framesize) + (obj.StackGuard - obj.StackSmall)
	}

	// common
	jls := obj.Appendp(ctxt, p)
	jls.As = AJLS
	jls.To.Type = obj.TYPE_BRANCH

	var last *obj.Prog
	for last = ctxt.Cursym.Text; last.Link != nil; last = last.Link {
	}

	spfix := obj.Appendp(ctxt, last)
	spfix.As = obj.ANOP
	spfix.Spadj = -framesize

	call := obj.Appendp(ctxt, spfix)
	call.Lineno = ctxt.Cursym.Text.Lineno
	call.Mode = ctxt.Cursym.Text.Mode
	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.From3Offset()&obj.NEEDCTXT == 0:
		morestack = "runtime.morestack_noctxt"
	}
	call.To.Sym = obj.Linklookup(ctxt, morestack, 0)

	jmp := obj.Appendp(ctxt, call)
	jmp.As = obj.AJMP
	jmp.To.Type = obj.TYPE_BRANCH
	jmp.Pcond = ctxt.Cursym.Text.Link
	jmp.Spadj = +framesize

	jls.Pcond = call
	if q1 != nil {
		q1.Pcond = call
	}

	return jls
}

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 nofollow(a obj.As) bool {
	switch a {
	case obj.AJMP,
		obj.ARET,
		AIRETL,
		AIRETQ,
		AIRETW,
		ARETFL,
		ARETFQ,
		ARETFW,
		obj.AUNDEF:
		return true
	}

	return false
}

func pushpop(a obj.As) bool {
	switch a {
	case APUSHL,
		APUSHFL,
		APUSHQ,
		APUSHFQ,
		APUSHW,
		APUSHFW,
		APOPL,
		APOPFL,
		APOPQ,
		APOPFQ,
		APOPW,
		APOPFW:
		return true
	}

	return false
}

func relinv(a obj.As) obj.As {
	switch a {
	case AJEQ:
		return AJNE
	case AJNE:
		return AJEQ
	case AJLE:
		return AJGT
	case AJLS:
		return AJHI
	case AJLT:
		return AJGE
	case AJMI:
		return AJPL
	case AJGE:
		return AJLT
	case AJPL:
		return AJMI
	case AJGT:
		return AJLE
	case AJHI:
		return AJLS
	case AJCS:
		return AJCC
	case AJCC:
		return AJCS
	case AJPS:
		return AJPC
	case AJPC:
		return AJPS
	case AJOS:
		return AJOC
	case AJOC:
		return AJOS
	}

	log.Fatalf("unknown relation: %s", obj.Aconv(a))
	return 0
}

func xfol(ctxt *obj.Link, p *obj.Prog, last **obj.Prog) {
	var q *obj.Prog
	var i int
	var a obj.As

loop:
	if p == nil {
		return
	}
	if p.As == obj.AJMP {
		q = p.Pcond
		if q != nil && q.As != obj.ATEXT {
			/* mark instruction as done and continue layout at target of jump */
			p.Mark |= DONE

			p = q
			if p.Mark&DONE == 0 {
				goto loop
			}
		}
	}

	if p.Mark&DONE != 0 {
		/*
		 * p goes here, but already used it elsewhere.
		 * copy up to 4 instructions or else branch to other copy.
		 */
		i = 0
		q = p
		for ; i < 4; i, q = i+1, q.Link {
			if q == nil {
				break
			}
			if q == *last {
				break
			}
			a = q.As
			if a == obj.ANOP {
				i--
				continue
			}

			if nofollow(a) || pushpop(a) {
				break // NOTE(rsc): arm does goto copy
			}
			if q.Pcond == nil || q.Pcond.Mark&DONE != 0 {
				continue
			}
			if a == obj.ACALL || a == ALOOP {
				continue
			}
			for {
				if p.As == obj.ANOP {
					p = p.Link
					continue
				}

				q = obj.Copyp(ctxt, p)
				p = p.Link
				q.Mark |= DONE
				(*last).Link = q
				*last = q
				if q.As != a || q.Pcond == nil || q.Pcond.Mark&DONE != 0 {
					continue
				}

				q.As = relinv(q.As)
				p = q.Pcond
				q.Pcond = q.Link
				q.Link = p
				xfol(ctxt, q.Link, last)
				p = q.Link
				if p.Mark&DONE != 0 {
					return
				}
				goto loop
				/* */
			}
		}
		q = ctxt.NewProg()
		q.As = obj.AJMP
		q.Lineno = p.Lineno
		q.To.Type = obj.TYPE_BRANCH
		q.To.Offset = p.Pc
		q.Pcond = p
		p = q
	}

	/* emit p */
	p.Mark |= DONE

	(*last).Link = p
	*last = p
	a = p.As

	/* continue loop with what comes after p */
	if nofollow(a) {
		return
	}
	if p.Pcond != nil && a != obj.ACALL {
		/*
		 * some kind of conditional branch.
		 * recurse to follow one path.
		 * continue loop on the other.
		 */
		q = obj.Brchain(ctxt, p.Pcond)
		if q != nil {
			p.Pcond = q
		}
		q = obj.Brchain(ctxt, p.Link)
		if q != nil {
			p.Link = q
		}
		if p.From.Type == obj.TYPE_CONST {
			if p.From.Offset == 1 {
				/*
				 * expect conditional jump to be taken.
				 * rewrite so that's the fall-through case.
				 */
				p.As = relinv(a)

				q = p.Link
				p.Link = p.Pcond
				p.Pcond = q
			}
		} else {
			q = p.Link
			if q.Mark&DONE != 0 {
				if a != ALOOP {
					p.As = relinv(a)
					p.Link = p.Pcond
					p.Pcond = q
				}
			}
		}

		xfol(ctxt, p.Link, last)
		if p.Pcond.Mark&DONE != 0 {
			return
		}
		p = p.Pcond
		goto loop
	}

	p = p.Link
	goto loop
}

var unaryDst = map[obj.As]bool{
	ABSWAPL:    true,
	ABSWAPQ:    true,
	ACMPXCHG8B: true,
	ADECB:      true,
	ADECL:      true,
	ADECQ:      true,
	ADECW:      true,
	AINCB:      true,
	AINCL:      true,
	AINCQ:      true,
	AINCW:      true,
	ANEGB:      true,
	ANEGL:      true,
	ANEGQ:      true,
	ANEGW:      true,
	ANOTB:      true,
	ANOTL:      true,
	ANOTQ:      true,
	ANOTW:      true,
	APOPL:      true,
	APOPQ:      true,
	APOPW:      true,
	ASETCC:     true,
	ASETCS:     true,
	ASETEQ:     true,
	ASETGE:     true,
	ASETGT:     true,
	ASETHI:     true,
	ASETLE:     true,
	ASETLS:     true,
	ASETLT:     true,
	ASETMI:     true,
	ASETNE:     true,
	ASETOC:     true,
	ASETOS:     true,
	ASETPC:     true,
	ASETPL:     true,
	ASETPS:     true,
	AFFREE:     true,
	AFLDENV:    true,
	AFSAVE:     true,
	AFSTCW:     true,
	AFSTENV:    true,
	AFSTSW:     true,
	AFXSAVE:    true,
	AFXSAVE64:  true,
	ASTMXCSR:   true,
}

var Linkamd64 = obj.LinkArch{
	ByteOrder:  binary.LittleEndian,
	Name:       "amd64",
	Thechar:    '6',
	Preprocess: preprocess,
	Assemble:   span6,
	Follow:     follow,
	Progedit:   progedit,
	UnaryDst:   unaryDst,
	Minlc:      1,
	Ptrsize:    8,
	Regsize:    8,
}

var Linkamd64p32 = obj.LinkArch{
	ByteOrder:  binary.LittleEndian,
	Name:       "amd64p32",
	Thechar:    '6',
	Preprocess: preprocess,
	Assemble:   span6,
	Follow:     follow,
	Progedit:   progedit,
	UnaryDst:   unaryDst,
	Minlc:      1,
	Ptrsize:    4,
	Regsize:    8,
}

var Link386 = obj.LinkArch{
	ByteOrder:  binary.LittleEndian,
	Name:       "386",
	Thechar:    '8',
	Preprocess: preprocess,
	Assemble:   span6,
	Follow:     follow,
	Progedit:   progedit,
	UnaryDst:   unaryDst,
	Minlc:      1,
	Ptrsize:    4,
	Regsize:    4,
}
Ejemplo n.º 26
0
// Rewrite p, if necessary, to access global data via the global offset table.
func rewriteToUseGot(ctxt *obj.Link, p *obj.Prog) {
	var add, lea, mov obj.As
	var reg int16
	if p.Mode == 64 {
		add = AADDQ
		lea = ALEAQ
		mov = AMOVQ
		reg = REG_R15
	} else {
		add = AADDL
		lea = ALEAL
		mov = AMOVL
		reg = REG_CX
	}

	if p.As == obj.ADUFFCOPY || p.As == obj.ADUFFZERO {
		//     ADUFFxxx $offset
		// becomes
		//     $MOV runtime.duffxxx@GOT, $reg
		//     $ADD $offset, $reg
		//     CALL $reg
		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 = mov
		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
		p.To.Offset = 0
		p.To.Sym = nil
		p1 := obj.Appendp(ctxt, p)
		p1.As = add
		p1.From.Type = obj.TYPE_CONST
		p1.From.Offset = offset
		p1.To.Type = obj.TYPE_REG
		p1.To.Reg = reg
		p2 := obj.Appendp(ctxt, p1)
		p2.As = obj.ACALL
		p2.To.Type = obj.TYPE_REG
		p2.To.Reg = reg
	}

	// 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.As == lea && p.From.Type == obj.TYPE_MEM && p.From.Name == obj.NAME_EXTERN && !p.From.Sym.Local {
		// $LEA sym, Rx becomes $MOV $sym, Rx which will be rewritten below
		p.As = mov
		p.From.Type = obj.TYPE_ADDR
	}
	if p.From.Type == obj.TYPE_ADDR && p.From.Name == obj.NAME_EXTERN && !p.From.Sym.Local {
		// $MOV $sym, Rx becomes $MOV sym@GOT, Rx
		// $MOV $sym+<off>, Rx becomes $MOV sym@GOT, Rx; $LEA <off>(Rx), Rx
		// On 386 only, more complicated things like PUSHL $sym become $MOV sym@GOT, CX; PUSHL CX
		cmplxdest := false
		pAs := p.As
		var dest obj.Addr
		if p.To.Type != obj.TYPE_REG || pAs != mov {
			if p.Mode == 64 {
				ctxt.Diag("do not know how to handle LEA-type insn to non-register in %v with -dynlink", p)
			}
			cmplxdest = true
			dest = p.To
			p.As = mov
			p.To.Type = obj.TYPE_REG
			p.To.Reg = REG_CX
			p.To.Sym = nil
			p.To.Name = obj.NAME_NONE
		}
		p.From.Type = obj.TYPE_MEM
		p.From.Name = obj.NAME_GOTREF
		q := p
		if p.From.Offset != 0 {
			q = obj.Appendp(ctxt, p)
			q.As = lea
			q.From.Type = obj.TYPE_MEM
			q.From.Reg = p.To.Reg
			q.From.Offset = p.From.Offset
			q.To = p.To
			p.From.Offset = 0
		}
		if cmplxdest {
			q = obj.Appendp(ctxt, q)
			q.As = pAs
			q.To = dest
			q.From.Type = obj.TYPE_REG
			q.From.Reg = REG_CX
		}
	}
	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 $MOV sym@GOT, R15; MOVx (R15), Ry
	// MOVx Ry, sym becomes $MOV sym@GOT, R15; MOVx Ry, (R15)
	// 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.ACALL {
		// When dynlinking on 386, almost any call might end up being a call
		// to a PLT, so make sure the GOT pointer is loaded into BX.
		// RegTo2 is set on the replacement call insn to stop it being
		// processed when it is in turn passed to progedit.
		if p.Mode == 64 || (p.To.Sym != nil && p.To.Sym.Local) || p.RegTo2 != 0 {
			return
		}
		p1 := obj.Appendp(ctxt, p)
		p2 := obj.Appendp(ctxt, p1)

		p1.As = ALEAL
		p1.From.Type = obj.TYPE_MEM
		p1.From.Name = obj.NAME_STATIC
		p1.From.Sym = obj.Linklookup(ctxt, "_GLOBAL_OFFSET_TABLE_", 0)
		p1.To.Type = obj.TYPE_REG
		p1.To.Reg = REG_BX

		p2.As = p.As
		p2.Scond = p.Scond
		p2.From = p.From
		p2.From3 = p.From3
		p2.Reg = p.Reg
		p2.To = p.To
		// p.To.Type was set to TYPE_BRANCH above, but that makes checkaddr
		// in ../pass.go complain, so set it back to TYPE_MEM here, until p2
		// itself gets passed to progedit.
		p2.To.Type = obj.TYPE_MEM
		p2.RegTo2 = 1

		obj.Nopout(p)
		return

	}
	if p.As == obj.ATEXT || p.As == obj.AFUNCDATA || p.As == obj.ARET || p.As == obj.AJMP {
		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 = mov
	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

	p2.As = p.As
	p2.From = p.From
	p2.To = p.To
	if p.From.Name == obj.NAME_EXTERN {
		p2.From.Reg = reg
		p2.From.Name = obj.NAME_NONE
		p2.From.Sym = nil
	} else if p.To.Name == obj.NAME_EXTERN {
		p2.To.Reg = reg
		p2.To.Name = obj.NAME_NONE
		p2.To.Sym = nil
	} else {
		return
	}
	obj.Nopout(p)
}
Ejemplo n.º 27
0
func peep(firstp *obj.Prog) {
	g := gc.Flowstart(firstp, nil)
	if g == nil {
		return
	}
	gactive = 0

	// byte, word arithmetic elimination.
	elimshortmov(g)

	// constant propagation
	// find MOV $con,R followed by
	// another MOV $con,R without
	// setting R in the interim
	var p *obj.Prog
	for r := g.Start; r != nil; r = r.Link {
		p = r.Prog
		switch p.As {
		case x86.ALEAL:
			if regtyp(&p.To) {
				if p.From.Sym != nil {
					if p.From.Index == x86.REG_NONE {
						conprop(r)
					}
				}
			}

		case x86.AMOVB,
			x86.AMOVW,
			x86.AMOVL,
			x86.AMOVSS,
			x86.AMOVSD:
			if regtyp(&p.To) {
				if p.From.Type == obj.TYPE_CONST || p.From.Type == obj.TYPE_FCONST {
					conprop(r)
				}
			}
		}
	}

	var r1 *gc.Flow
	var p1 *obj.Prog
	var r *gc.Flow
	var t int
loop1:
	if gc.Debug['P'] != 0 && gc.Debug['v'] != 0 {
		gc.Dumpit("loop1", g.Start, 0)
	}

	t = 0
	for r = g.Start; r != nil; r = r.Link {
		p = r.Prog
		switch p.As {
		case x86.AMOVL,
			x86.AMOVSS,
			x86.AMOVSD:
			if regtyp(&p.To) {
				if regtyp(&p.From) {
					if copyprop(g, r) {
						excise(r)
						t++
					} else if subprop(r) && copyprop(g, r) {
						excise(r)
						t++
					}
				}
			}

		case x86.AMOVBLZX,
			x86.AMOVWLZX,
			x86.AMOVBLSX,
			x86.AMOVWLSX:
			if regtyp(&p.To) {
				r1 = rnops(gc.Uniqs(r))
				if r1 != nil {
					p1 = r1.Prog
					if p.As == p1.As && p.To.Type == p1.From.Type && p.To.Reg == p1.From.Reg {
						p1.As = x86.AMOVL
						t++
					}
				}
			}

		case x86.AADDL,
			x86.AADDW:
			if p.From.Type != obj.TYPE_CONST || needc(p.Link) {
				break
			}
			if p.From.Offset == -1 {
				if p.As == x86.AADDL {
					p.As = x86.ADECL
				} else {
					p.As = x86.ADECW
				}
				p.From = obj.Addr{}
				break
			}

			if p.From.Offset == 1 {
				if p.As == x86.AADDL {
					p.As = x86.AINCL
				} else {
					p.As = x86.AINCW
				}
				p.From = obj.Addr{}
				break
			}

		case x86.ASUBL,
			x86.ASUBW:
			if p.From.Type != obj.TYPE_CONST || needc(p.Link) {
				break
			}
			if p.From.Offset == -1 {
				if p.As == x86.ASUBL {
					p.As = x86.AINCL
				} else {
					p.As = x86.AINCW
				}
				p.From = obj.Addr{}
				break
			}

			if p.From.Offset == 1 {
				if p.As == x86.ASUBL {
					p.As = x86.ADECL
				} else {
					p.As = x86.ADECW
				}
				p.From = obj.Addr{}
				break
			}
		}
	}

	if t != 0 {
		goto loop1
	}

	// MOVSD removal.
	// We never use packed registers, so a MOVSD between registers
	// can be replaced by MOVAPD, which moves the pair of float64s
	// instead of just the lower one.  We only use the lower one, but
	// the processor can do better if we do moves using both.
	for r := g.Start; r != nil; r = r.Link {
		p = r.Prog
		if p.As == x86.AMOVSD {
			if regtyp(&p.From) {
				if regtyp(&p.To) {
					p.As = x86.AMOVAPD
				}
			}
		}
	}

	gc.Flowend(g)
}
Ejemplo n.º 28
0
Archivo: peep.go Proyecto: danny8002/go
// movb elimination.
// movb is simulated by the linker
// when a register other than ax, bx, cx, dx
// is used, so rewrite to other instructions
// when possible.  a movb into a register
// can smash the entire 32-bit register without
// causing any trouble.
//
// TODO: Using the Q forms here instead of the L forms
// seems unnecessary, and it makes the instructions longer.
func elimshortmov(g *gc.Graph) {
	var p *obj.Prog

	for r := (*gc.Flow)(g.Start); r != nil; r = r.Link {
		p = r.Prog
		if regtyp(&p.To) {
			switch p.As {
			case x86.AINCB,
				x86.AINCW:
				p.As = x86.AINCQ

			case x86.ADECB,
				x86.ADECW:
				p.As = x86.ADECQ

			case x86.ANEGB,
				x86.ANEGW:
				p.As = x86.ANEGQ

			case x86.ANOTB,
				x86.ANOTW:
				p.As = x86.ANOTQ
			}

			if regtyp(&p.From) || p.From.Type == obj.TYPE_CONST {
				// move or artihmetic into partial register.
				// from another register or constant can be movl.
				// we don't switch to 64-bit arithmetic if it can
				// change how the carry bit is set (and the carry bit is needed).
				switch p.As {
				case x86.AMOVB,
					x86.AMOVW:
					p.As = x86.AMOVQ

				case x86.AADDB,
					x86.AADDW:
					if !needc(p.Link) {
						p.As = x86.AADDQ
					}

				case x86.ASUBB,
					x86.ASUBW:
					if !needc(p.Link) {
						p.As = x86.ASUBQ
					}

				case x86.AMULB,
					x86.AMULW:
					p.As = x86.AMULQ

				case x86.AIMULB,
					x86.AIMULW:
					p.As = x86.AIMULQ

				case x86.AANDB,
					x86.AANDW:
					p.As = x86.AANDQ

				case x86.AORB,
					x86.AORW:
					p.As = x86.AORQ

				case x86.AXORB,
					x86.AXORW:
					p.As = x86.AXORQ

				case x86.ASHLB,
					x86.ASHLW:
					p.As = x86.ASHLQ
				}
			} else if p.From.Type != obj.TYPE_REG {
				// explicit zero extension, but don't
				// do that if source is a byte register
				// (only AH can occur and it's forbidden).
				switch p.As {
				case x86.AMOVB:
					p.As = x86.AMOVBQZX

				case x86.AMOVW:
					p.As = x86.AMOVWQZX
				}
			}
		}
	}
}
Ejemplo n.º 29
0
func progedit(ctxt *obj.Link, p *obj.Prog) {
	// Maintain information about code generation mode.
	if ctxt.Mode == 0 {
		ctxt.Mode = ctxt.Arch.Regsize * 8
	}
	p.Mode = int8(ctxt.Mode)

	switch p.As {
	case AMODE:
		if p.From.Type == obj.TYPE_CONST || (p.From.Type == obj.TYPE_MEM && p.From.Reg == REG_NONE) {
			switch int(p.From.Offset) {
			case 16, 32, 64:
				ctxt.Mode = int(p.From.Offset)
			}
		}
		obj.Nopout(p)
	}

	// Thread-local storage references use the TLS pseudo-register.
	// As a register, TLS refers to the thread-local storage base, and it
	// can only be loaded into another register:
	//
	//         MOVQ TLS, AX
	//
	// An offset from the thread-local storage base is written off(reg)(TLS*1).
	// Semantically it is off(reg), but the (TLS*1) annotation marks this as
	// indexing from the loaded TLS base. This emits a relocation so that
	// if the linker needs to adjust the offset, it can. For example:
	//
	//         MOVQ TLS, AX
	//         MOVQ 0(AX)(TLS*1), CX // load g into CX
	//
	// On systems that support direct access to the TLS memory, this
	// pair of instructions can be reduced to a direct TLS memory reference:
	//
	//         MOVQ 0(TLS), CX // load g into CX
	//
	// The 2-instruction and 1-instruction forms correspond to the two code
	// sequences for loading a TLS variable in the local exec model given in "ELF
	// Handling For Thread-Local Storage".
	//
	// We apply this rewrite on systems that support the 1-instruction form.
	// The decision is made using only the operating system and the -shared flag,
	// not the link mode. If some link modes on a particular operating system
	// require the 2-instruction form, then all builds for that operating system
	// will use the 2-instruction form, so that the link mode decision can be
	// delayed to link time.
	//
	// In this way, all supported systems use identical instructions to
	// access TLS, and they are rewritten appropriately first here in
	// liblink and then finally using relocations in the linker.
	//
	// When -shared is passed, we leave the code in the 2-instruction form but
	// assemble (and relocate) them in different ways to generate the initial
	// exec code sequence. It's a bit of a fluke that this is possible without
	// rewriting the instructions more comprehensively, and it only does because
	// we only support a single TLS variable (g).

	if CanUse1InsnTLS(ctxt) {
		// Reduce 2-instruction sequence to 1-instruction sequence.
		// Sequences like
		//	MOVQ TLS, BX
		//	... off(BX)(TLS*1) ...
		// become
		//	NOP
		//	... off(TLS) ...
		//
		// TODO(rsc): Remove the Hsolaris special case. It exists only to
		// guarantee we are producing byte-identical binaries as before this code.
		// But it should be unnecessary.
		if (p.As == AMOVQ || p.As == AMOVL) && p.From.Type == obj.TYPE_REG && p.From.Reg == REG_TLS && p.To.Type == obj.TYPE_REG && REG_AX <= p.To.Reg && p.To.Reg <= REG_R15 && ctxt.Headtype != obj.Hsolaris {
			obj.Nopout(p)
		}
		if p.From.Type == obj.TYPE_MEM && p.From.Index == REG_TLS && REG_AX <= p.From.Reg && p.From.Reg <= REG_R15 {
			p.From.Reg = REG_TLS
			p.From.Scale = 0
			p.From.Index = REG_NONE
		}

		if p.To.Type == obj.TYPE_MEM && p.To.Index == REG_TLS && REG_AX <= p.To.Reg && p.To.Reg <= REG_R15 {
			p.To.Reg = REG_TLS
			p.To.Scale = 0
			p.To.Index = REG_NONE
		}
	} else {
		// load_g_cx, below, always inserts the 1-instruction sequence. Rewrite it
		// as the 2-instruction sequence if necessary.
		//	MOVQ 0(TLS), BX
		// becomes
		//	MOVQ TLS, BX
		//	MOVQ 0(BX)(TLS*1), BX
		if (p.As == AMOVQ || p.As == AMOVL) && p.From.Type == obj.TYPE_MEM && p.From.Reg == REG_TLS && p.To.Type == obj.TYPE_REG && REG_AX <= p.To.Reg && p.To.Reg <= REG_R15 {
			q := obj.Appendp(ctxt, p)
			q.As = p.As
			q.From = p.From
			q.From.Type = obj.TYPE_MEM
			q.From.Reg = p.To.Reg
			q.From.Index = REG_TLS
			q.From.Scale = 2 // TODO: use 1
			q.To = p.To
			p.From.Type = obj.TYPE_REG
			p.From.Reg = REG_TLS
			p.From.Index = REG_NONE
			p.From.Offset = 0
		}
	}

	// TODO: Remove.
	if ctxt.Headtype == obj.Hwindows && p.Mode == 64 || ctxt.Headtype == obj.Hplan9 {
		if p.From.Scale == 1 && p.From.Index == REG_TLS {
			p.From.Scale = 2
		}
		if p.To.Scale == 1 && p.To.Index == REG_TLS {
			p.To.Scale = 2
		}
	}

	// Rewrite 0 to $0 in 3rd argument to CMPPS etc.
	// That's what the tables expect.
	switch p.As {
	case ACMPPD, ACMPPS, ACMPSD, ACMPSS:
		if p.To.Type == obj.TYPE_MEM && p.To.Name == obj.NAME_NONE && p.To.Reg == REG_NONE && p.To.Index == REG_NONE && p.To.Sym == nil {
			p.To.Type = obj.TYPE_CONST
		}
	}

	// Rewrite CALL/JMP/RET to symbol as TYPE_BRANCH.
	switch p.As {
	case obj.ACALL, obj.AJMP, obj.ARET:
		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
		}
	}

	// Rewrite MOVL/MOVQ $XXX(FP/SP) as LEAL/LEAQ.
	if p.From.Type == obj.TYPE_ADDR && (ctxt.Arch.Thechar == '6' || p.From.Name != obj.NAME_EXTERN && p.From.Name != obj.NAME_STATIC) {
		switch p.As {
		case AMOVL:
			p.As = ALEAL
			p.From.Type = obj.TYPE_MEM
		case AMOVQ:
			p.As = ALEAQ
			p.From.Type = obj.TYPE_MEM
		}
	}

	if ctxt.Headtype == obj.Hnacl && p.Mode == 64 {
		if p.From3 != nil {
			nacladdr(ctxt, p, p.From3)
		}
		nacladdr(ctxt, p, &p.From)
		nacladdr(ctxt, p, &p.To)
	}

	// Rewrite float constants to values stored in memory.
	switch p.As {
	// Convert AMOVSS $(0), Xx to AXORPS Xx, Xx
	case AMOVSS:
		if p.From.Type == obj.TYPE_FCONST {
			//  f == 0 can't be used here due to -0, so use Float64bits
			if f := p.From.Val.(float64); math.Float64bits(f) == 0 {
				if p.To.Type == obj.TYPE_REG && REG_X0 <= p.To.Reg && p.To.Reg <= REG_X15 {
					p.As = AXORPS
					p.From = p.To
					break
				}
			}
		}
		fallthrough

	case AFMOVF,
		AFADDF,
		AFSUBF,
		AFSUBRF,
		AFMULF,
		AFDIVF,
		AFDIVRF,
		AFCOMF,
		AFCOMFP,
		AADDSS,
		ASUBSS,
		AMULSS,
		ADIVSS,
		ACOMISS,
		AUCOMISS:
		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)
			p.From.Type = obj.TYPE_MEM
			p.From.Name = obj.NAME_EXTERN
			p.From.Sym = s
			p.From.Sym.Local = true
			p.From.Offset = 0
		}

	case AMOVSD:
		// Convert AMOVSD $(0), Xx to AXORPS Xx, Xx
		if p.From.Type == obj.TYPE_FCONST {
			//  f == 0 can't be used here due to -0, so use Float64bits
			if f := p.From.Val.(float64); math.Float64bits(f) == 0 {
				if p.To.Type == obj.TYPE_REG && REG_X0 <= p.To.Reg && p.To.Reg <= REG_X15 {
					p.As = AXORPS
					p.From = p.To
					break
				}
			}
		}
		fallthrough

	case AFMOVD,
		AFADDD,
		AFSUBD,
		AFSUBRD,
		AFMULD,
		AFDIVD,
		AFDIVRD,
		AFCOMD,
		AFCOMDP,
		AADDSD,
		ASUBSD,
		AMULSD,
		ADIVSD,
		ACOMISD,
		AUCOMISD:
		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)
			p.From.Type = obj.TYPE_MEM
			p.From.Name = obj.NAME_EXTERN
			p.From.Sym = s
			p.From.Sym.Local = true
			p.From.Offset = 0
		}
	}

	if ctxt.Flag_dynlink {
		rewriteToUseGot(ctxt, p)
	}

	if ctxt.Flag_shared != 0 && p.Mode == 32 {
		rewriteToPcrel(ctxt, p)
	}
}
Ejemplo n.º 30
0
Archivo: peep.go Proyecto: danny8002/go
func peep(firstp *obj.Prog) {
	g := (*gc.Graph)(gc.Flowstart(firstp, nil))
	if g == nil {
		return
	}
	gactive = 0

	// byte, word arithmetic elimination.
	elimshortmov(g)

	// constant propagation
	// find MOV $con,R followed by
	// another MOV $con,R without
	// setting R in the interim
	var p *obj.Prog
	for r := (*gc.Flow)(g.Start); r != nil; r = r.Link {
		p = r.Prog
		switch p.As {
		case x86.ALEAL,
			x86.ALEAQ:
			if regtyp(&p.To) {
				if p.From.Sym != nil {
					if p.From.Index == x86.REG_NONE {
						conprop(r)
					}
				}
			}

		case x86.AMOVB,
			x86.AMOVW,
			x86.AMOVL,
			x86.AMOVQ,
			x86.AMOVSS,
			x86.AMOVSD:
			if regtyp(&p.To) {
				if p.From.Type == obj.TYPE_CONST || p.From.Type == obj.TYPE_FCONST {
					conprop(r)
				}
			}
		}
	}

	var r *gc.Flow
	var r1 *gc.Flow
	var p1 *obj.Prog
	var t int
loop1:
	if gc.Debug['P'] != 0 && gc.Debug['v'] != 0 {
		gc.Dumpit("loop1", g.Start, 0)
	}

	t = 0
	for r = g.Start; r != nil; r = r.Link {
		p = r.Prog
		switch p.As {
		case x86.AMOVL,
			x86.AMOVQ,
			x86.AMOVSS,
			x86.AMOVSD:
			if regtyp(&p.To) {
				if regtyp(&p.From) {
					if copyprop(g, r) {
						excise(r)
						t++
					} else if subprop(r) && copyprop(g, r) {
						excise(r)
						t++
					}
				}
			}

		case x86.AMOVBLZX,
			x86.AMOVWLZX,
			x86.AMOVBLSX,
			x86.AMOVWLSX:
			if regtyp(&p.To) {
				r1 = rnops(gc.Uniqs(r))
				if r1 != nil {
					p1 = r1.Prog
					if p.As == p1.As && p.To.Type == p1.From.Type && p.To.Reg == p1.From.Reg {
						p1.As = x86.AMOVL
						t++
					}
				}
			}

		case x86.AMOVBQSX,
			x86.AMOVBQZX,
			x86.AMOVWQSX,
			x86.AMOVWQZX,
			x86.AMOVLQSX,
			x86.AMOVLQZX,
			x86.AMOVQL:
			if regtyp(&p.To) {
				r1 = rnops(gc.Uniqs(r))
				if r1 != nil {
					p1 = r1.Prog
					if p.As == p1.As && p.To.Type == p1.From.Type && p.To.Reg == p1.From.Reg {
						p1.As = x86.AMOVQ
						t++
					}
				}
			}

		case x86.AADDL,
			x86.AADDQ,
			x86.AADDW:
			if p.From.Type != obj.TYPE_CONST || needc(p.Link) {
				break
			}
			if p.From.Offset == -1 {
				if p.As == x86.AADDQ {
					p.As = x86.ADECQ
				} else if p.As == x86.AADDL {
					p.As = x86.ADECL
				} else {
					p.As = x86.ADECW
				}
				p.From = obj.Addr{}
				break
			}

			if p.From.Offset == 1 {
				if p.As == x86.AADDQ {
					p.As = x86.AINCQ
				} else if p.As == x86.AADDL {
					p.As = x86.AINCL
				} else {
					p.As = x86.AINCW
				}
				p.From = obj.Addr{}
				break
			}

		case x86.ASUBL,
			x86.ASUBQ,
			x86.ASUBW:
			if p.From.Type != obj.TYPE_CONST || needc(p.Link) {
				break
			}
			if p.From.Offset == -1 {
				if p.As == x86.ASUBQ {
					p.As = x86.AINCQ
				} else if p.As == x86.ASUBL {
					p.As = x86.AINCL
				} else {
					p.As = x86.AINCW
				}
				p.From = obj.Addr{}
				break
			}

			if p.From.Offset == 1 {
				if p.As == x86.ASUBQ {
					p.As = x86.ADECQ
				} else if p.As == x86.ASUBL {
					p.As = x86.ADECL
				} else {
					p.As = x86.ADECW
				}
				p.From = obj.Addr{}
				break
			}
		}
	}

	if t != 0 {
		goto loop1
	}

	// MOVLQZX removal.
	// The MOVLQZX exists to avoid being confused for a
	// MOVL that is just copying 32-bit data around during
	// copyprop.  Now that copyprop is done, remov MOVLQZX R1, R2
	// if it is dominated by an earlier ADDL/MOVL/etc into R1 that
	// will have already cleared the high bits.
	//
	// MOVSD removal.
	// We never use packed registers, so a MOVSD between registers
	// can be replaced by MOVAPD, which moves the pair of float64s
	// instead of just the lower one.  We only use the lower one, but
	// the processor can do better if we do moves using both.
	for r := (*gc.Flow)(g.Start); r != nil; r = r.Link {
		p = r.Prog
		if p.As == x86.AMOVLQZX {
			if regtyp(&p.From) {
				if p.From.Type == p.To.Type && p.From.Reg == p.To.Reg {
					if prevl(r, int(p.From.Reg)) {
						excise(r)
					}
				}
			}
		}

		if p.As == x86.AMOVSD {
			if regtyp(&p.From) {
				if regtyp(&p.To) {
					p.As = x86.AMOVAPD
				}
			}
		}
	}

	// load pipelining
	// push any load from memory as early as possible
	// to give it time to complete before use.
	for r := (*gc.Flow)(g.Start); r != nil; r = r.Link {
		p = r.Prog
		switch p.As {
		case x86.AMOVB,
			x86.AMOVW,
			x86.AMOVL,
			x86.AMOVQ,
			x86.AMOVLQZX:
			if regtyp(&p.To) && !regconsttyp(&p.From) {
				pushback(r)
			}
		}
	}

	gc.Flowend(g)
}