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// Derived from Inferno utils/6c/peep.c
// http://code.google.com/p/inferno-os/source/browse/utils/6c/peep.c
//
// Copyright © 1994-1999 Lucent Technologies Inc. All rights reserved.
// Portions Copyright © 1995-1997 C H Forsyth (forsyth@terzarima.net)
// Portions Copyright © 1997-1999 Vita Nuova Limited
// Portions Copyright © 2000-2007 Vita Nuova Holdings Limited (www.vitanuova.com)
// Portions Copyright © 2004,2006 Bruce Ellis
// Portions Copyright © 2005-2007 C H Forsyth (forsyth@terzarima.net)
// Revisions Copyright © 2000-2007 Lucent Technologies Inc. and others
// Portions Copyright © 2009 The Go Authors. All rights reserved.
//
// Permission is hereby granted, free of charge, to any person obtaining a copy
// of this software and associated documentation files (the "Software"), to deal
// in the Software without restriction, including without limitation the rights
// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
// copies of the Software, and to permit persons to whom the Software is
// furnished to do so, subject to the following conditions:
//
// The above copyright notice and this permission notice shall be included in
// all copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
// THE SOFTWARE.
package arm64
import (
"cmd/compile/internal/gc"
"cmd/internal/obj"
"cmd/internal/obj/arm64"
"fmt"
)
var gactive uint32
func peep(firstp *obj.Prog) {
g := (*gc.Graph)(gc.Flowstart(firstp, nil))
if g == nil {
return
}
gactive = 0
var p *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
// TODO(minux) Handle smaller moves. arm and amd64
// distinguish between 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 == arm64.AMOVD || p.As == arm64.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++
}
}
}
}
}
}
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 := (*gc.Flow)(g.Start); r != nil; r = r.Link {
p = r.Prog
switch p.As {
default:
continue
case arm64.AMOVH,
arm64.AMOVHU,
arm64.AMOVB,
arm64.AMOVBU,
arm64.AMOVW,
arm64.AMOVWU:
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 */
}
// MOVD $c, R'; ADD R', R (R' unused) -> ADD $c, R
for r := (*gc.Flow)(g.Start); r != nil; r = r.Link {
p = r.Prog
switch p.As {
default:
continue
case arm64.AMOVD:
if p.To.Type != obj.TYPE_REG {
continue
}
if p.From.Type != obj.TYPE_CONST {
continue
}
if p.From.Offset < 0 || 4096 <= p.From.Offset {
continue
}
}
r1 = r.Link
if r1 == nil {
continue
}
p1 = r1.Prog
if p1.As != arm64.AADD && p1.As != arm64.ASUB { // TODO(aram): also logical after we have bimm.
continue
}
if p1.From.Type != obj.TYPE_REG || p1.From.Reg != p.To.Reg {
continue
}
if p1.To.Type != obj.TYPE_REG {
continue
}
if gc.Debug['P'] != 0 {
fmt.Printf("encoding $%d directly into %v in:\n%v\n%v\n", p.From.Offset, obj.Aconv(int(p1.As)), p, p1)
}
p1.From.Type = obj.TYPE_CONST
p1.From = p.From
excise(r)
}
/* TODO(minux):
* look for OP x,y,R; CMP R, $0 -> OP.S x,y,R
* when OP can set condition codes correctly
*/
ret:
gc.Flowend(g)
}
func excise(r *gc.Flow) {
p := (*obj.Prog)(r.Prog)
if gc.Debug['P'] != 0 && gc.Debug['v'] != 0 {
fmt.Printf("%v ===delete===\n", p)
}
obj.Nopout(p)
gc.Ostats.Ndelmov++
}
func regtyp(a *obj.Addr) bool {
// TODO(rsc): Floating point register exclusions?
return a.Type == obj.TYPE_REG && arm64.REG_R0 <= a.Reg && a.Reg <= arm64.REG_F31 && a.Reg != arm64.REGZERO
}
/*
* the idea is to substitute
* one register for another
* from one MOV to another
* MOV a, R1
* ADD b, R1 / no use of R2
* MOV R1, R2
* would be converted to
* MOV a, R2
* ADD b, R2
* MOV R2, R1
* hopefully, then the former or latter MOV
* will be eliminated by copy propagation.
*
* r0 (the argument, not the register) is the MOV at the end of the
* above sequences. This returns 1 if it modified any instructions.
*/
func subprop(r0 *gc.Flow) bool {
p := (*obj.Prog)(r0.Prog)
v1 := (*obj.Addr)(&p.From)
if !regtyp(v1) {
return false
}
v2 := (*obj.Addr)(&p.To)
if !regtyp(v2) {
return false
}
for r := gc.Uniqp(r0); r != nil; r = gc.Uniqp(r) {
if gc.Uniqs(r) == nil {
break
}
p = r.Prog
if p.As == obj.AVARDEF || p.As == obj.AVARKILL {
continue
}
if p.Info.Flags&gc.Call != 0 {
return false
}
if p.Info.Flags&(gc.RightRead|gc.RightWrite) == gc.RightWrite {
if p.To.Type == v1.Type {
if p.To.Reg == v1.Reg {
copysub(&p.To, v1, v2, 1)
if gc.Debug['P'] != 0 {
fmt.Printf("gotit: %v->%v\n%v", gc.Ctxt.Dconv(v1), gc.Ctxt.Dconv(v2), r.Prog)
if p.From.Type == v2.Type {
fmt.Printf(" excise")
}
fmt.Printf("\n")
}
for r = gc.Uniqs(r); r != r0; r = gc.Uniqs(r) {
p = r.Prog
copysub(&p.From, v1, v2, 1)
copysub1(p, v1, v2, 1)
copysub(&p.To, v1, v2, 1)
if gc.Debug['P'] != 0 {
fmt.Printf("%v\n", r.Prog)
}
}
t := int(int(v1.Reg))
v1.Reg = v2.Reg
v2.Reg = int16(t)
if gc.Debug['P'] != 0 {
fmt.Printf("%v last\n", r.Prog)
}
return true
}
}
}
if copyau(&p.From, v2) || copyau1(p, v2) || copyau(&p.To, v2) {
break
}
if copysub(&p.From, v1, v2, 0) != 0 || copysub1(p, v1, v2, 0) != 0 || copysub(&p.To, v1, v2, 0) != 0 {
break
}
}
return false
}
/*
* The idea is to remove redundant copies.
* v1->v2 F=0
* (use v2 s/v2/v1/)*
* set v1 F=1
* use v2 return fail (v1->v2 move must remain)
* -----------------
* v1->v2 F=0
* (use v2 s/v2/v1/)*
* set v1 F=1
* set v2 return success (caller can remove v1->v2 move)
*/
func copyprop(r0 *gc.Flow) bool {
p := (*obj.Prog)(r0.Prog)
v1 := (*obj.Addr)(&p.From)
v2 := (*obj.Addr)(&p.To)
if copyas(v1, v2) {
if gc.Debug['P'] != 0 {
fmt.Printf("eliminating self-move: %v\n", r0.Prog)
}
return true
}
gactive++
if gc.Debug['P'] != 0 {
fmt.Printf("trying to eliminate %v->%v move from:\n%v\n", gc.Ctxt.Dconv(v1), gc.Ctxt.Dconv(v2), r0.Prog)
}
return copy1(v1, v2, r0.S1, 0)
}
// copy1 replaces uses of v2 with v1 starting at r and returns 1 if
// all uses were rewritten.
func copy1(v1 *obj.Addr, v2 *obj.Addr, r *gc.Flow, f int) bool {
if uint32(r.Active) == gactive {
if gc.Debug['P'] != 0 {
fmt.Printf("act set; return 1\n")
}
return true
}
r.Active = int32(gactive)
if gc.Debug['P'] != 0 {
fmt.Printf("copy1 replace %v with %v f=%d\n", gc.Ctxt.Dconv(v2), gc.Ctxt.Dconv(v1), f)
}
var t int
var p *obj.Prog
for ; r != nil; r = r.S1 {
p = r.Prog
if gc.Debug['P'] != 0 {
fmt.Printf("%v", p)
}
if f == 0 && gc.Uniqp(r) == nil {
// Multiple predecessors; conservatively
// assume v1 was set on other path
f = 1
if gc.Debug['P'] != 0 {
fmt.Printf("; merge; f=%d", f)
}
}
t = copyu(p, v2, nil)
switch t {
case 2: /* rar, can't split */
if gc.Debug['P'] != 0 {
fmt.Printf("; %v rar; return 0\n", gc.Ctxt.Dconv(v2))
}
return false
case 3: /* set */
if gc.Debug['P'] != 0 {
fmt.Printf("; %v set; return 1\n", gc.Ctxt.Dconv(v2))
}
return true
case 1, /* used, substitute */
4: /* use and set */
if f != 0 {
if gc.Debug['P'] == 0 {
return false
}
if t == 4 {
fmt.Printf("; %v used+set and f=%d; return 0\n", gc.Ctxt.Dconv(v2), f)
} else {
fmt.Printf("; %v used and f=%d; return 0\n", gc.Ctxt.Dconv(v2), f)
}
return false
}
if copyu(p, v2, v1) != 0 {
if gc.Debug['P'] != 0 {
fmt.Printf("; sub fail; return 0\n")
}
return false
}
if gc.Debug['P'] != 0 {
fmt.Printf("; sub %v->%v\n => %v", gc.Ctxt.Dconv(v2), gc.Ctxt.Dconv(v1), p)
}
if t == 4 {
if gc.Debug['P'] != 0 {
fmt.Printf("; %v used+set; return 1\n", gc.Ctxt.Dconv(v2))
}
return true
}
}
if f == 0 {
t = copyu(p, v1, nil)
if f == 0 && (t == 2 || t == 3 || t == 4) {
f = 1
if gc.Debug['P'] != 0 {
fmt.Printf("; %v set and !f; f=%d", gc.Ctxt.Dconv(v1), f)
}
}
}
if gc.Debug['P'] != 0 {
fmt.Printf("\n")
}
if r.S2 != nil {
if !copy1(v1, v2, r.S2, f) {
return false
}
}
}
return true
}
// If s==nil, copyu returns the set/use of v in p; otherwise, it
// modifies p to replace reads of v with reads of s and returns 0 for
// success or non-zero for failure.
//
// If s==nil, copy returns one of the following values:
// 1 if v only used
// 2 if v is set and used in one address (read-alter-rewrite;
// can't substitute)
// 3 if v is only set
// 4 if v is set in one address and used in another (so addresses
// can be rewritten independently)
// 0 otherwise (not touched)
func copyu(p *obj.Prog, v *obj.Addr, s *obj.Addr) int {
if p.From3Type() != obj.TYPE_NONE {
// 7g never generates a from3
fmt.Printf("copyu: from3 (%v) not implemented\n", gc.Ctxt.Dconv(p.From3))
}
if p.RegTo2 != obj.REG_NONE {
// 7g never generates a to2
fmt.Printf("copyu: RegTo2 (%v) not implemented\n", obj.Rconv(int(p.RegTo2)))
}
switch p.As {
default:
fmt.Printf("copyu: can't find %v\n", obj.Aconv(int(p.As)))
return 2
case obj.ANOP, /* read p->from, write p->to */
arm64.ANEG,
arm64.AFNEGD,
arm64.AFNEGS,
arm64.AFSQRTD,
arm64.AFCVTZSD,
arm64.AFCVTZSS,
arm64.AFCVTZSDW,
arm64.AFCVTZSSW,
arm64.AFCVTZUD,
arm64.AFCVTZUS,
arm64.AFCVTZUDW,
arm64.AFCVTZUSW,
arm64.AFCVTSD,
arm64.AFCVTDS,
arm64.ASCVTFD,
arm64.ASCVTFS,
arm64.ASCVTFWD,
arm64.ASCVTFWS,
arm64.AUCVTFD,
arm64.AUCVTFS,
arm64.AUCVTFWD,
arm64.AUCVTFWS,
arm64.AMOVB,
arm64.AMOVBU,
arm64.AMOVH,
arm64.AMOVHU,
arm64.AMOVW,
arm64.AMOVWU,
arm64.AMOVD,
arm64.AFMOVS,
arm64.AFMOVD:
if p.Scond == 0 {
if s != nil {
if copysub(&p.From, v, s, 1) != 0 {
return 1
}
// Update only indirect uses of v in p->to
if !copyas(&p.To, v) {
if copysub(&p.To, v, s, 1) != 0 {
return 1
}
}
return 0
}
if copyas(&p.To, v) {
// Fix up implicit from
if p.From.Type == obj.TYPE_NONE {
p.From = p.To
}
if copyau(&p.From, v) {
return 4
}
return 3
}
if copyau(&p.From, v) {
return 1
}
if copyau(&p.To, v) {
// p->to only indirectly uses v
return 1
}
return 0
}
/* rar p->from, write p->to or read p->from, rar p->to */
if p.From.Type == obj.TYPE_MEM {
if copyas(&p.From, v) {
// No s!=nil check; need to fail
// anyway in that case
return 2
}
if s != nil {
if copysub(&p.To, v, s, 1) != 0 {
return 1
}
return 0
}
if copyas(&p.To, v) {
return 3
}
} else if p.To.Type == obj.TYPE_MEM {
if copyas(&p.To, v) {
return 2
}
if s != nil {
if copysub(&p.From, v, s, 1) != 0 {
return 1
}
return 0
}
if copyau(&p.From, v) {
return 1
}
} else {
fmt.Printf("copyu: bad %v\n", p)
}
return 0
case arm64.AADD, /* read p->from, read p->reg, write p->to */
arm64.ASUB,
arm64.AAND,
arm64.AORR,
arm64.AEOR,
arm64.AMUL,
arm64.ASMULL,
arm64.AUMULL,
arm64.ASMULH,
arm64.AUMULH,
arm64.ASDIV,
arm64.AUDIV,
arm64.ALSL,
arm64.ALSR,
arm64.AASR,
arm64.AFADDD,
arm64.AFADDS,
arm64.AFSUBD,
arm64.AFSUBS,
arm64.AFMULD,
arm64.AFMULS,
arm64.AFDIVD,
arm64.AFDIVS:
if s != nil {
if copysub(&p.From, v, s, 1) != 0 {
return 1
}
if copysub1(p, v, s, 1) != 0 {
return 1
}
// Update only indirect uses of v in p->to
if !copyas(&p.To, v) {
if copysub(&p.To, v, s, 1) != 0 {
return 1
}
}
return 0
}
if copyas(&p.To, v) {
if p.Reg == 0 {
// Fix up implicit reg (e.g., ADD
// R3,R4 -> ADD R3,R4,R4) so we can
// update reg and to separately.
p.Reg = p.To.Reg
}
if copyau(&p.From, v) {
return 4
}
if copyau1(p, v) {
return 4
}
return 3
}
if copyau(&p.From, v) {
return 1
}
if copyau1(p, v) {
return 1
}
if copyau(&p.To, v) {
return 1
}
return 0
case arm64.ABEQ,
arm64.ABNE,
arm64.ABGE,
arm64.ABLT,
arm64.ABGT,
arm64.ABLE,
arm64.ABLO,
arm64.ABLS,
arm64.ABHI,
arm64.ABHS:
return 0
case obj.ACHECKNIL, /* read p->from */
arm64.ACMP, /* read p->from, read p->reg */
arm64.AFCMPD,
arm64.AFCMPS:
if s != nil {
if copysub(&p.From, v, s, 1) != 0 {
return 1
}
return copysub1(p, v, s, 1)
}
if copyau(&p.From, v) {
return 1
}
if copyau1(p, v) {
return 1
}
return 0
case arm64.AB: /* read p->to */
if s != nil {
if copysub(&p.To, v, s, 1) != 0 {
return 1
}
return 0
}
if copyau(&p.To, v) {
return 1
}
return 0
case obj.ARET: /* funny */
if s != nil {
return 0
}
// All registers die at this point, so claim
// everything is set (and not used).
return 3
case arm64.ABL: /* funny */
if p.From.Type == obj.TYPE_REG && v.Type == obj.TYPE_REG && p.From.Reg == v.Reg {
return 2
}
if s != nil {
if copysub(&p.To, v, s, 1) != 0 {
return 1
}
return 0
}
if copyau(&p.To, v) {
return 4
}
return 3
// R31 is zero, used by DUFFZERO, cannot be substituted.
// R16 is ptr to memory, used and set, cannot be substituted.
case obj.ADUFFZERO:
if v.Type == obj.TYPE_REG {
if v.Reg == 31 {
return 1
}
if v.Reg == 16 {
return 2
}
}
return 0
// R16, R17 are ptr to src, dst, used and set, cannot be substituted.
// R27 is scratch, set by DUFFCOPY, cannot be substituted.
case obj.ADUFFCOPY:
if v.Type == obj.TYPE_REG {
if v.Reg == 16 || v.Reg == 17 {
return 2
}
if v.Reg == 27 {
return 3
}
}
return 0
case arm64.AHINT,
obj.ATEXT,
obj.APCDATA,
obj.AFUNCDATA,
obj.AVARDEF,
obj.AVARKILL:
return 0
}
}
// copyas returns 1 if a and v address the same register.
//
// If a is the from operand, this means this operation reads the
// register in v. If a is the to operand, this means this operation
// writes the register in v.
func copyas(a *obj.Addr, v *obj.Addr) bool {
if regtyp(v) {
if a.Type == v.Type {
if a.Reg == v.Reg {
return true
}
}
}
return false
}
// copyau returns 1 if a either directly or indirectly addresses the
// same register as v.
//
// If a is the from operand, this means this operation reads the
// register in v. If a is the to operand, this means the operation
// either reads or writes the register in v (if !copyas(a, v), then
// the operation reads the register in v).
func copyau(a *obj.Addr, v *obj.Addr) bool {
if copyas(a, v) {
return true
}
if v.Type == obj.TYPE_REG {
if a.Type == obj.TYPE_MEM || (a.Type == obj.TYPE_ADDR && a.Reg != 0) {
if v.Reg == a.Reg {
return true
}
}
}
return false
}
// copyau1 returns 1 if p->reg references the same register as v and v
// is a direct reference.
func copyau1(p *obj.Prog, v *obj.Addr) bool {
if regtyp(v) && v.Reg != 0 {
if p.Reg == v.Reg {
return true
}
}
return false
}
// copysub replaces v with s in a if f!=0 or indicates it if could if f==0.
// Returns 1 on failure to substitute (it always succeeds on arm64).
func copysub(a *obj.Addr, v *obj.Addr, s *obj.Addr, f int) int {
if f != 0 {
if copyau(a, v) {
a.Reg = s.Reg
}
}
return 0
}
// copysub1 replaces v with s in p1->reg if f!=0 or indicates if it could if f==0.
// Returns 1 on failure to substitute (it always succeeds on arm64).
func copysub1(p1 *obj.Prog, v *obj.Addr, s *obj.Addr, f int) int {
if f != 0 {
if copyau1(p1, v) {
p1.Reg = s.Reg
}
}
return 0
}
func sameaddr(a *obj.Addr, v *obj.Addr) bool {
if a.Type != v.Type {
return false
}
if regtyp(v) && a.Reg == v.Reg {
return true
}
if v.Type == obj.NAME_AUTO || v.Type == obj.NAME_PARAM {
if v.Offset == a.Offset {
return true
}
}
return false
}
func smallindir(a *obj.Addr, reg *obj.Addr) bool {
return reg.Type == obj.TYPE_REG && a.Type == obj.TYPE_MEM && a.Reg == reg.Reg && 0 <= a.Offset && a.Offset < 4096
}
func stackaddr(a *obj.Addr) bool {
return a.Type == obj.TYPE_REG && a.Reg == arm64.REGSP
}