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go/src/cmd/compile/internal/gc/cgen.go
Keith Randall bfe0cbdc50 cmd/compile,runtime: pass elem type to {make,grow}slice 
No point in passing the slice type to these functions.
All they need is the element type.  One less indirection,
maybe a few less []T type descriptors in the binary.

Change-Id: Ib0b83b5f14ca21d995ecc199ce8ac00c4eb375e6
Reviewed-on: https://go-review.googlesource.com/22275
Reviewed-by: Josh Bleecher Snyder <josharian@gmail.com>
2016-04-20 00:31:16 +00:00

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// Copyright 2009 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package gc
import (
"cmd/internal/obj"
"cmd/internal/obj/ppc64"
"cmd/internal/sys"
"fmt"
)
// generate:
// res = n;
// simplifies and calls Thearch.Gmove.
// if wb is true, need to emit write barriers.
func Cgen(n, res *Node) {
cgen_wb(n, res, false)
}
func cgen_wb(n, res *Node, wb bool) {
if Debug['g'] != 0 {
op := "cgen"
if wb {
op = "cgen_wb"
}
Dump("\n"+op+"-n", n)
Dump(op+"-res", res)
}
if n == nil || n.Type == nil {
return
}
if res == nil || res.Type == nil {
Fatalf("cgen: res nil")
}
for n.Op == OCONVNOP {
n = n.Left
}
switch n.Op {
case OSLICE, OSLICEARR, OSLICESTR, OSLICE3, OSLICE3ARR:
cgen_slice(n, res, wb)
return
case OEFACE:
if res.Op != ONAME || !res.Addable || wb {
var n1 Node
Tempname(&n1, n.Type)
Cgen_eface(n, &n1)
cgen_wb(&n1, res, wb)
} else {
Cgen_eface(n, res)
}
return
case ODOTTYPE:
cgen_dottype(n, res, nil, wb)
return
case OAPPEND:
cgen_append(n, res)
return
}
if n.Ullman >= UINF {
if n.Op == OINDREG {
Fatalf("cgen: this is going to miscompile")
}
if res.Ullman >= UINF {
var n1 Node
Tempname(&n1, n.Type)
Cgen(n, &n1)
cgen_wb(&n1, res, wb)
return
}
}
if Isfat(n.Type) {
if n.Type.Width < 0 {
Fatalf("forgot to compute width for %v", n.Type)
}
sgen_wb(n, res, n.Type.Width, wb)
return
}
if !res.Addable {
if n.Ullman > res.Ullman {
if Ctxt.Arch.RegSize == 4 && Is64(n.Type) {
var n1 Node
Tempname(&n1, n.Type)
Cgen(n, &n1)
cgen_wb(&n1, res, wb)
return
}
var n1 Node
Regalloc(&n1, n.Type, res)
Cgen(n, &n1)
if n1.Ullman > res.Ullman {
Dump("n1", &n1)
Dump("res", res)
Fatalf("loop in cgen")
}
cgen_wb(&n1, res, wb)
Regfree(&n1)
return
}
if res.Ullman < UINF {
if Complexop(n, res) {
Complexgen(n, res)
return
}
f := true // gen through register
switch n.Op {
case OLITERAL:
if Smallintconst(n) {
f = false
}
case OREGISTER:
f = false
}
if !n.Type.IsComplex() && Ctxt.Arch.RegSize == 8 && !wb {
a := Thearch.Optoas(OAS, res.Type)
var addr obj.Addr
if Thearch.Sudoaddable(a, res, &addr) {
var p1 *obj.Prog
if f {
var n2 Node
Regalloc(&n2, res.Type, nil)
Cgen(n, &n2)
p1 = Thearch.Gins(a, &n2, nil)
Regfree(&n2)
} else {
p1 = Thearch.Gins(a, n, nil)
}
p1.To = addr
if Debug['g'] != 0 {
fmt.Printf("%v [ignore previous line]\n", p1)
}
Thearch.Sudoclean()
return
}
}
}
if Ctxt.Arch.Family == sys.I386 {
// no registers to speak of
var n1, n2 Node
Tempname(&n1, n.Type)
Cgen(n, &n1)
Igen(res, &n2, nil)
cgen_wb(&n1, &n2, wb)
Regfree(&n2)
return
}
var n1 Node
Igen(res, &n1, nil)
cgen_wb(n, &n1, wb)
Regfree(&n1)
return
}
// update addressability for string, slice
// can't do in walk because n->left->addable
// changes if n->left is an escaping local variable.
switch n.Op {
case OSPTR, OLEN:
if n.Left.Type.IsSlice() || n.Left.Type.IsString() {
n.Addable = n.Left.Addable
}
case OCAP:
if n.Left.Type.IsSlice() {
n.Addable = n.Left.Addable
}
case OITAB:
n.Addable = n.Left.Addable
}
if wb {
if Simtype[res.Type.Etype] != Tptr {
Fatalf("cgen_wb of type %v", res.Type)
}
if n.Ullman >= UINF {
var n1 Node
Tempname(&n1, n.Type)
Cgen(n, &n1)
n = &n1
}
cgen_wbptr(n, res)
return
}
// Write barrier now handled. Code below this line can ignore wb.
if Ctxt.Arch.Family == sys.ARM { // TODO(rsc): Maybe more often?
// if both are addressable, move
if n.Addable && res.Addable {
if Is64(n.Type) || Is64(res.Type) || n.Op == OREGISTER || res.Op == OREGISTER || n.Type.IsComplex() || res.Type.IsComplex() {
Thearch.Gmove(n, res)
} else {
var n1 Node
Regalloc(&n1, n.Type, nil)
Thearch.Gmove(n, &n1)
Cgen(&n1, res)
Regfree(&n1)
}
return
}
// if both are not addressable, use a temporary.
if !n.Addable && !res.Addable {
// could use regalloc here sometimes,
// but have to check for ullman >= UINF.
var n1 Node
Tempname(&n1, n.Type)
Cgen(n, &n1)
Cgen(&n1, res)
return
}
// if result is not addressable directly but n is,
// compute its address and then store via the address.
if !res.Addable {
var n1 Node
Igen(res, &n1, nil)
Cgen(n, &n1)
Regfree(&n1)
return
}
}
if Complexop(n, res) {
Complexgen(n, res)
return
}
if Ctxt.Arch.InFamily(sys.AMD64, sys.I386, sys.S390X) && n.Addable {
Thearch.Gmove(n, res)
return
}
if Ctxt.Arch.InFamily(sys.ARM64, sys.MIPS64, sys.PPC64) {
// if both are addressable, move
if n.Addable {
if n.Op == OREGISTER || res.Op == OREGISTER {
Thearch.Gmove(n, res)
} else {
var n1 Node
Regalloc(&n1, n.Type, nil)
Thearch.Gmove(n, &n1)
Cgen(&n1, res)
Regfree(&n1)
}
return
}
}
// if n is sudoaddable generate addr and move
if Ctxt.Arch.Family == sys.ARM && !Is64(n.Type) && !Is64(res.Type) && !n.Type.IsComplex() && !res.Type.IsComplex() {
a := Thearch.Optoas(OAS, n.Type)
var addr obj.Addr
if Thearch.Sudoaddable(a, n, &addr) {
if res.Op != OREGISTER {
var n2 Node
Regalloc(&n2, res.Type, nil)
p1 := Thearch.Gins(a, nil, &n2)
p1.From = addr
if Debug['g'] != 0 {
fmt.Printf("%v [ignore previous line]\n", p1)
}
Thearch.Gmove(&n2, res)
Regfree(&n2)
} else {
p1 := Thearch.Gins(a, nil, res)
p1.From = addr
if Debug['g'] != 0 {
fmt.Printf("%v [ignore previous line]\n", p1)
}
}
Thearch.Sudoclean()
return
}
}
nl := n.Left
nr := n.Right
if nl != nil && nl.Ullman >= UINF {
if nr != nil && nr.Ullman >= UINF {
var n1 Node
Tempname(&n1, nl.Type)
Cgen(nl, &n1)
n2 := *n
n2.Left = &n1
Cgen(&n2, res)
return
}
}
// 64-bit ops are hard on 32-bit machine.
if Ctxt.Arch.RegSize == 4 && (Is64(n.Type) || Is64(res.Type) || n.Left != nil && Is64(n.Left.Type)) {
switch n.Op {
// math goes to cgen64.
case OMINUS,
OCOM,
OADD,
OSUB,
OMUL,
OLROT,
OLSH,
ORSH,
OAND,
OOR,
OXOR:
Thearch.Cgen64(n, res)
return
}
}
if Thearch.Cgen_float != nil && nl != nil && n.Type.IsFloat() && nl.Type.IsFloat() {
Thearch.Cgen_float(n, res)
return
}
if !n.Type.IsComplex() && Ctxt.Arch.RegSize == 8 {
a := Thearch.Optoas(OAS, n.Type)
var addr obj.Addr
if Thearch.Sudoaddable(a, n, &addr) {
if res.Op == OREGISTER {
p1 := Thearch.Gins(a, nil, res)
p1.From = addr
} else {
var n2 Node
Regalloc(&n2, n.Type, nil)
p1 := Thearch.Gins(a, nil, &n2)
p1.From = addr
Thearch.Gins(a, &n2, res)
Regfree(&n2)
}
Thearch.Sudoclean()
return
}
}
var a obj.As
switch n.Op {
default:
Dump("cgen", n)
Dump("cgen-res", res)
Fatalf("cgen: unknown op %v", Nconv(n, FmtShort|FmtSign))
case OOROR, OANDAND,
OEQ, ONE,
OLT, OLE,
OGE, OGT,
ONOT:
Bvgen(n, res, true)
return
case OPLUS:
Cgen(nl, res)
return
// unary
case OCOM:
a := Thearch.Optoas(OXOR, nl.Type)
var n1 Node
Regalloc(&n1, nl.Type, nil)
Cgen(nl, &n1)
var n2 Node
Nodconst(&n2, nl.Type, -1)
Thearch.Gins(a, &n2, &n1)
cgen_norm(n, &n1, res)
return
case OMINUS:
if nl.Type.IsFloat() {
nr = Nodintconst(-1)
nr = convlit(nr, n.Type)
a = Thearch.Optoas(OMUL, nl.Type)
goto sbop
}
a := Thearch.Optoas(n.Op, nl.Type)
// unary
var n1 Node
Regalloc(&n1, nl.Type, res)
Cgen(nl, &n1)
if Ctxt.Arch.Family == sys.ARM {
var n2 Node
Nodconst(&n2, nl.Type, 0)
Thearch.Gins(a, &n2, &n1)
} else if Ctxt.Arch.Family == sys.ARM64 {
Thearch.Gins(a, &n1, &n1)
} else {
Thearch.Gins(a, nil, &n1)
}
cgen_norm(n, &n1, res)
return
case OSQRT:
var n1 Node
Regalloc(&n1, nl.Type, res)
Cgen(n.Left, &n1)
Thearch.Gins(Thearch.Optoas(OSQRT, nl.Type), &n1, &n1)
Thearch.Gmove(&n1, res)
Regfree(&n1)
return
case OGETG:
Thearch.Getg(res)
return
// symmetric binary
case OAND,
OOR,
OXOR,
OADD,
OMUL:
if n.Op == OMUL && Thearch.Cgen_bmul != nil && Thearch.Cgen_bmul(n.Op, nl, nr, res) {
break
}
a = Thearch.Optoas(n.Op, nl.Type)
goto sbop
// asymmetric binary
case OSUB:
a = Thearch.Optoas(n.Op, nl.Type)
goto abop
case OHMUL:
Thearch.Cgen_hmul(nl, nr, res)
case OCONV:
if Eqtype(n.Type, nl.Type) || Noconv(n.Type, nl.Type) {
Cgen(nl, res)
return
}
if Ctxt.Arch.Family == sys.I386 {
var n1 Node
var n2 Node
Tempname(&n2, n.Type)
Mgen(nl, &n1, res)
Thearch.Gmove(&n1, &n2)
Thearch.Gmove(&n2, res)
Mfree(&n1)
break
}
var n1 Node
var n2 Node
if Ctxt.Arch.Family == sys.ARM {
if nl.Addable && !Is64(nl.Type) {
Regalloc(&n1, nl.Type, res)
Thearch.Gmove(nl, &n1)
} else {
if n.Type.Width > int64(Widthptr) || Is64(nl.Type) || nl.Type.IsFloat() {
Tempname(&n1, nl.Type)
} else {
Regalloc(&n1, nl.Type, res)
}
Cgen(nl, &n1)
}
if n.Type.Width > int64(Widthptr) || Is64(n.Type) || n.Type.IsFloat() {
Tempname(&n2, n.Type)
} else {
Regalloc(&n2, n.Type, nil)
}
} else {
if n.Type.Width > nl.Type.Width {
// If loading from memory, do conversion during load,
// so as to avoid use of 8-bit register in, say, int(*byteptr).
switch nl.Op {
case ODOT, ODOTPTR, OINDEX, OIND, ONAME:
Igen(nl, &n1, res)
Regalloc(&n2, n.Type, res)
Thearch.Gmove(&n1, &n2)
Thearch.Gmove(&n2, res)
Regfree(&n2)
Regfree(&n1)
return
}
}
Regalloc(&n1, nl.Type, res)
Regalloc(&n2, n.Type, &n1)
Cgen(nl, &n1)
}
// if we do the conversion n1 -> n2 here
// reusing the register, then gmove won't
// have to allocate its own register.
Thearch.Gmove(&n1, &n2)
Thearch.Gmove(&n2, res)
if n2.Op == OREGISTER {
Regfree(&n2)
}
if n1.Op == OREGISTER {
Regfree(&n1)
}
case ODOT,
ODOTPTR,
OINDEX,
OIND,
ONAME: // PHEAP or PPARAMREF var
var n1 Node
Igen(n, &n1, res)
Thearch.Gmove(&n1, res)
Regfree(&n1)
// interface table is first word of interface value
case OITAB:
var n1 Node
Igen(nl, &n1, res)
n1.Type = n.Type
Thearch.Gmove(&n1, res)
Regfree(&n1)
case OSPTR:
// pointer is the first word of string or slice.
if Isconst(nl, CTSTR) {
var n1 Node
Regalloc(&n1, Types[Tptr], res)
p1 := Thearch.Gins(Thearch.Optoas(OAS, n1.Type), nil, &n1)
Datastring(nl.Val().U.(string), &p1.From)
p1.From.Type = obj.TYPE_ADDR
Thearch.Gmove(&n1, res)
Regfree(&n1)
break
}
var n1 Node
Igen(nl, &n1, res)
n1.Type = n.Type
Thearch.Gmove(&n1, res)
Regfree(&n1)
case OLEN:
if nl.Type.IsMap() || nl.Type.IsChan() {
// map and chan have len in the first int-sized word.
// a zero pointer means zero length
var n1 Node
Regalloc(&n1, Types[Tptr], res)
Cgen(nl, &n1)
var n2 Node
Nodconst(&n2, Types[Tptr], 0)
p1 := Thearch.Ginscmp(OEQ, Types[Tptr], &n1, &n2, 0)
n2 = n1
n2.Op = OINDREG
n2.Type = Types[Simtype[TINT]]
Thearch.Gmove(&n2, &n1)
Patch(p1, Pc)
Thearch.Gmove(&n1, res)
Regfree(&n1)
break
}
if nl.Type.IsString() || nl.Type.IsSlice() {
// both slice and string have len one pointer into the struct.
// a zero pointer means zero length
var n1 Node
Igen(nl, &n1, res)
n1.Type = Types[Simtype[TUINT]]
n1.Xoffset += int64(Array_nel)
Thearch.Gmove(&n1, res)
Regfree(&n1)
break
}
Fatalf("cgen: OLEN: unknown type %v", Tconv(nl.Type, FmtLong))
case OCAP:
if nl.Type.IsChan() {
// chan has cap in the second int-sized word.
// a zero pointer means zero length
var n1 Node
Regalloc(&n1, Types[Tptr], res)
Cgen(nl, &n1)
var n2 Node
Nodconst(&n2, Types[Tptr], 0)
p1 := Thearch.Ginscmp(OEQ, Types[Tptr], &n1, &n2, 0)
n2 = n1
n2.Op = OINDREG
n2.Xoffset = int64(Widthint)
n2.Type = Types[Simtype[TINT]]
Thearch.Gmove(&n2, &n1)
Patch(p1, Pc)
Thearch.Gmove(&n1, res)
Regfree(&n1)
break
}
if nl.Type.IsSlice() {
var n1 Node
Igen(nl, &n1, res)
n1.Type = Types[Simtype[TUINT]]
n1.Xoffset += int64(Array_cap)
Thearch.Gmove(&n1, res)
Regfree(&n1)
break
}
Fatalf("cgen: OCAP: unknown type %v", Tconv(nl.Type, FmtLong))
case OADDR:
if n.Bounded { // let race detector avoid nil checks
Disable_checknil++
}
Agen(nl, res)
if n.Bounded {
Disable_checknil--
}
case OCALLMETH:
cgen_callmeth(n, 0)
cgen_callret(n, res)
case OCALLINTER:
cgen_callinter(n, res, 0)
cgen_callret(n, res)
case OCALLFUNC:
cgen_call(n, 0)
cgen_callret(n, res)
case OMOD, ODIV:
if n.Type.IsFloat() || Thearch.Dodiv == nil {
a = Thearch.Optoas(n.Op, nl.Type)
goto abop
}
if nl.Ullman >= nr.Ullman {
var n1 Node
Regalloc(&n1, nl.Type, res)
Cgen(nl, &n1)
cgen_div(n.Op, &n1, nr, res)
Regfree(&n1)
} else {
var n2 Node
if !Smallintconst(nr) {
Regalloc(&n2, nr.Type, res)
Cgen(nr, &n2)
} else {
n2 = *nr
}
cgen_div(n.Op, nl, &n2, res)
if n2.Op != OLITERAL {
Regfree(&n2)
}
}
case OLSH, ORSH, OLROT:
Thearch.Cgen_shift(n.Op, n.Bounded, nl, nr, res)
}
return
// put simplest on right - we'll generate into left
// and then adjust it using the computation of right.
// constants and variables have the same ullman
// count, so look for constants specially.
//
// an integer constant we can use as an immediate
// is simpler than a variable - we can use the immediate
// in the adjustment instruction directly - so it goes
// on the right.
//
// other constants, like big integers or floating point
// constants, require a mov into a register, so those
// might as well go on the left, so we can reuse that
// register for the computation.
sbop: // symmetric binary
if nl.Ullman < nr.Ullman || (nl.Ullman == nr.Ullman && (Smallintconst(nl) || (nr.Op == OLITERAL && !Smallintconst(nr)))) {
nl, nr = nr, nl
}
abop: // asymmetric binary
var n1 Node
var n2 Node
if Ctxt.Arch.Family == sys.I386 {
// no registers, sigh
if Smallintconst(nr) {
var n1 Node
Mgen(nl, &n1, res)
var n2 Node
Regalloc(&n2, nl.Type, &n1)
Thearch.Gmove(&n1, &n2)
Thearch.Gins(a, nr, &n2)
Thearch.Gmove(&n2, res)
Regfree(&n2)
Mfree(&n1)
} else if nl.Ullman >= nr.Ullman {
var nt Node
Tempname(&nt, nl.Type)
Cgen(nl, &nt)
var n2 Node
Mgen(nr, &n2, nil)
var n1 Node
Regalloc(&n1, nl.Type, res)
Thearch.Gmove(&nt, &n1)
Thearch.Gins(a, &n2, &n1)
Thearch.Gmove(&n1, res)
Regfree(&n1)
Mfree(&n2)
} else {
var n2 Node
Regalloc(&n2, nr.Type, res)
Cgen(nr, &n2)
var n1 Node
Regalloc(&n1, nl.Type, nil)
Cgen(nl, &n1)
Thearch.Gins(a, &n2, &n1)
Regfree(&n2)
Thearch.Gmove(&n1, res)
Regfree(&n1)
}
return
}
if nl.Ullman >= nr.Ullman {
Regalloc(&n1, nl.Type, res)
Cgen(nl, &n1)
if Smallintconst(nr) && Ctxt.Arch.Family != sys.MIPS64 && Ctxt.Arch.Family != sys.ARM && Ctxt.Arch.Family != sys.ARM64 && Ctxt.Arch.Family != sys.PPC64 { // TODO(rsc): Check opcode for arm
n2 = *nr
} else {
Regalloc(&n2, nr.Type, nil)
Cgen(nr, &n2)
}
} else {
if Smallintconst(nr) && Ctxt.Arch.Family != sys.MIPS64 && Ctxt.Arch.Family != sys.ARM && Ctxt.Arch.Family != sys.ARM64 && Ctxt.Arch.Family != sys.PPC64 { // TODO(rsc): Check opcode for arm
n2 = *nr
} else {
Regalloc(&n2, nr.Type, res)
Cgen(nr, &n2)
}
Regalloc(&n1, nl.Type, nil)
Cgen(nl, &n1)
}
Thearch.Gins(a, &n2, &n1)
if n2.Op != OLITERAL {
Regfree(&n2)
}
cgen_norm(n, &n1, res)
}
var sys_wbptr *Node
func cgen_wbptr(n, res *Node) {
if Curfn != nil {
if Curfn.Func.Pragma&Nowritebarrier != 0 {
Yyerror("write barrier prohibited")
}
if Curfn.Func.WBLineno == 0 {
Curfn.Func.WBLineno = lineno
}
}
if Debug_wb > 0 {
Warn("write barrier")
}
var dst, src Node
Igen(res, &dst, nil)
if n.Op == OREGISTER {
src = *n
Regrealloc(&src)
} else {
Cgenr(n, &src, nil)
}
wbVar := syslook("writeBarrier")
wbEnabled := NodSym(ODOT, wbVar, wbVar.Type.Field(0).Sym)
wbEnabled = typecheck(wbEnabled, Erv)
pbr := Thearch.Ginscmp(ONE, Types[TUINT8], wbEnabled, Nodintconst(0), -1)
Thearch.Gins(Thearch.Optoas(OAS, Types[Tptr]), &src, &dst)
pjmp := Gbranch(obj.AJMP, nil, 0)
Patch(pbr, Pc)
var adst Node
Agenr(&dst, &adst, &dst)
p := Thearch.Gins(Thearch.Optoas(OAS, Types[Tptr]), &adst, nil)
a := &p.To
a.Type = obj.TYPE_MEM
a.Reg = int16(Thearch.REGSP)
a.Offset = Ctxt.FixedFrameSize()
p2 := Thearch.Gins(Thearch.Optoas(OAS, Types[Tptr]), &src, nil)
p2.To = p.To
p2.To.Offset += int64(Widthptr)
Regfree(&adst)
if sys_wbptr == nil {
sys_wbptr = writebarrierfn("writebarrierptr", Types[Tptr], Types[Tptr])
}
Ginscall(sys_wbptr, 0)
Patch(pjmp, Pc)
Regfree(&dst)
Regfree(&src)
}
func cgen_wbfat(n, res *Node) {
if Curfn != nil {
if Curfn.Func.Pragma&Nowritebarrier != 0 {
Yyerror("write barrier prohibited")
}
if Curfn.Func.WBLineno == 0 {
Curfn.Func.WBLineno = lineno
}
}
if Debug_wb > 0 {
Warn("write barrier")
}
needType := true
funcName := "typedmemmove"
var dst, src Node
if n.Ullman >= res.Ullman {
Agenr(n, &src, nil)
Agenr(res, &dst, nil)
} else {
Agenr(res, &dst, nil)
Agenr(n, &src, nil)
}
p := Thearch.Gins(Thearch.Optoas(OAS, Types[Tptr]), &dst, nil)
a := &p.To
a.Type = obj.TYPE_MEM
a.Reg = int16(Thearch.REGSP)
a.Offset = Ctxt.FixedFrameSize()
if needType {
a.Offset += int64(Widthptr)
}
p2 := Thearch.Gins(Thearch.Optoas(OAS, Types[Tptr]), &src, nil)
p2.To = p.To
p2.To.Offset += int64(Widthptr)
Regfree(&dst)
if needType {
src.Type = Types[Tptr]
Thearch.Gins(Thearch.Optoas(OAS, Types[Tptr]), typename(n.Type), &src)
p3 := Thearch.Gins(Thearch.Optoas(OAS, Types[Tptr]), &src, nil)
p3.To = p2.To
p3.To.Offset -= 2 * int64(Widthptr)
}
Regfree(&src)
Ginscall(writebarrierfn(funcName, Types[Tptr], Types[Tptr]), 0)
}
// cgen_norm moves n1 to res, truncating to expected type if necessary.
// n1 is a register, and cgen_norm frees it.
func cgen_norm(n, n1, res *Node) {
switch Ctxt.Arch.Family {
case sys.AMD64, sys.I386:
// We use sized math, so the result is already truncated.
default:
switch n.Op {
case OADD, OSUB, OMUL, ODIV, OCOM, OMINUS:
// TODO(rsc): What about left shift?
Thearch.Gins(Thearch.Optoas(OAS, n.Type), n1, n1)
}
}
Thearch.Gmove(n1, res)
Regfree(n1)
}
func Mgen(n *Node, n1 *Node, rg *Node) {
n1.Op = OEMPTY
if n.Addable {
*n1 = *n
if n1.Op == OREGISTER || n1.Op == OINDREG {
reg[n.Reg-int16(Thearch.REGMIN)]++
}
return
}
Tempname(n1, n.Type)
Cgen(n, n1)
if n.Type.Width <= int64(Widthptr) || n.Type.IsFloat() {
n2 := *n1
Regalloc(n1, n.Type, rg)
Thearch.Gmove(&n2, n1)
}
}
func Mfree(n *Node) {
if n.Op == OREGISTER {
Regfree(n)
}
}
// allocate a register (reusing res if possible) and generate
// a = n
// The caller must call Regfree(a).
func Cgenr(n *Node, a *Node, res *Node) {
if Debug['g'] != 0 {
Dump("cgenr-n", n)
}
if Isfat(n.Type) {
Fatalf("cgenr on fat node")
}
if n.Addable {
Regalloc(a, n.Type, res)
Thearch.Gmove(n, a)
return
}
switch n.Op {
case ONAME,
ODOT,
ODOTPTR,
OINDEX,
OCALLFUNC,
OCALLMETH,
OCALLINTER:
var n1 Node
Igen(n, &n1, res)
Regalloc(a, n.Type, &n1)
Thearch.Gmove(&n1, a)
Regfree(&n1)
default:
Regalloc(a, n.Type, res)
Cgen(n, a)
}
}
// allocate a register (reusing res if possible) and generate
// a = &n
// The caller must call Regfree(a).
// The generated code checks that the result is not nil.
func Agenr(n *Node, a *Node, res *Node) {
if Debug['g'] != 0 {
Dump("\nagenr-n", n)
}
nl := n.Left
nr := n.Right
switch n.Op {
case ODOT, ODOTPTR, OCALLFUNC, OCALLMETH, OCALLINTER:
var n1 Node
Igen(n, &n1, res)
Regalloc(a, Types[Tptr], &n1)
Agen(&n1, a)
Regfree(&n1)
case OIND:
Cgenr(n.Left, a, res)
Cgen_checknil(a)
case OINDEX:
if Ctxt.Arch.Family == sys.ARM {
var p2 *obj.Prog // to be patched to panicindex.
w := uint32(n.Type.Width)
bounded := Debug['B'] != 0 || n.Bounded
var n1 Node
var n3 Node
if nr.Addable {
var tmp Node
if !Isconst(nr, CTINT) {
Tempname(&tmp, Types[TINT32])
}
if !Isconst(nl, CTSTR) {
Agenr(nl, &n3, res)
}
if !Isconst(nr, CTINT) {
p2 = Thearch.Cgenindex(nr, &tmp, bounded)
Regalloc(&n1, tmp.Type, nil)
Thearch.Gmove(&tmp, &n1)
}
} else if nl.Addable {
if !Isconst(nr, CTINT) {
var tmp Node
Tempname(&tmp, Types[TINT32])
p2 = Thearch.Cgenindex(nr, &tmp, bounded)
Regalloc(&n1, tmp.Type, nil)
Thearch.Gmove(&tmp, &n1)
}
if !Isconst(nl, CTSTR) {
Agenr(nl, &n3, res)
}
} else {
var tmp Node
Tempname(&tmp, Types[TINT32])
p2 = Thearch.Cgenindex(nr, &tmp, bounded)
nr = &tmp
if !Isconst(nl, CTSTR) {
Agenr(nl, &n3, res)
}
Regalloc(&n1, tmp.Type, nil)
Thearch.Gins(Thearch.Optoas(OAS, tmp.Type), &tmp, &n1)
}
// &a is in &n3 (allocated in res)
// i is in &n1 (if not constant)
// w is width
// constant index
if Isconst(nr, CTINT) {
if Isconst(nl, CTSTR) {
Fatalf("constant string constant index")
}
v := uint64(nr.Int64())
var n2 Node
if nl.Type.IsSlice() || nl.Type.IsString() {
if Debug['B'] == 0 && !n.Bounded {
n1 = n3
n1.Op = OINDREG
n1.Type = Types[Tptr]
n1.Xoffset = int64(Array_nel)
Nodconst(&n2, Types[TUINT32], int64(v))
p1 := Thearch.Ginscmp(OGT, Types[TUINT32], &n1, &n2, +1)
Ginscall(Panicindex, -1)
Patch(p1, Pc)
}
n1 = n3
n1.Op = OINDREG
n1.Type = Types[Tptr]
n1.Xoffset = int64(Array_array)
Thearch.Gmove(&n1, &n3)
}
Nodconst(&n2, Types[Tptr], int64(v*uint64(w)))
Thearch.Gins(Thearch.Optoas(OADD, Types[Tptr]), &n2, &n3)
*a = n3
break
}
var n2 Node
Regalloc(&n2, Types[TINT32], &n1) // i
Thearch.Gmove(&n1, &n2)
Regfree(&n1)
var n4 Node
if Debug['B'] == 0 && !n.Bounded {
// check bounds
if Isconst(nl, CTSTR) {
Nodconst(&n4, Types[TUINT32], int64(len(nl.Val().U.(string))))
} else if nl.Type.IsSlice() || nl.Type.IsString() {
n1 = n3
n1.Op = OINDREG
n1.Type = Types[Tptr]
n1.Xoffset = int64(Array_nel)
Regalloc(&n4, Types[TUINT32], nil)
Thearch.Gmove(&n1, &n4)
} else {
Nodconst(&n4, Types[TUINT32], nl.Type.NumElem())
}
p1 := Thearch.Ginscmp(OLT, Types[TUINT32], &n2, &n4, +1)
if n4.Op == OREGISTER {
Regfree(&n4)
}
if p2 != nil {
Patch(p2, Pc)
}
Ginscall(Panicindex, -1)
Patch(p1, Pc)
}
if Isconst(nl, CTSTR) {
Regalloc(&n3, Types[Tptr], res)
p1 := Thearch.Gins(Thearch.Optoas(OAS, Types[Tptr]), nil, &n3)
Datastring(nl.Val().U.(string), &p1.From)
p1.From.Type = obj.TYPE_ADDR
} else if nl.Type.IsSlice() || nl.Type.IsString() {
n1 = n3
n1.Op = OINDREG
n1.Type = Types[Tptr]
n1.Xoffset = int64(Array_array)
Thearch.Gmove(&n1, &n3)
}
if w == 0 {
// nothing to do
} else if Thearch.AddIndex != nil && Thearch.AddIndex(&n2, int64(w), &n3) {
// done by back end
} else if w == 1 {
Thearch.Gins(Thearch.Optoas(OADD, Types[Tptr]), &n2, &n3)
} else {
if w&(w-1) == 0 {
// Power of 2. Use shift.
Thearch.Ginscon(Thearch.Optoas(OLSH, Types[TUINT32]), int64(log2(uint64(w))), &n2)
} else {
// Not a power of 2. Use multiply.
Regalloc(&n4, Types[TUINT32], nil)
Nodconst(&n1, Types[TUINT32], int64(w))
Thearch.Gmove(&n1, &n4)
Thearch.Gins(Thearch.Optoas(OMUL, Types[TUINT32]), &n4, &n2)
Regfree(&n4)
}
Thearch.Gins(Thearch.Optoas(OADD, Types[Tptr]), &n2, &n3)
}
*a = n3
Regfree(&n2)
break
}
if Ctxt.Arch.Family == sys.I386 {
var p2 *obj.Prog // to be patched to panicindex.
w := uint32(n.Type.Width)
bounded := Debug['B'] != 0 || n.Bounded
var n3 Node
var tmp Node
var n1 Node
if nr.Addable {
// Generate &nl first, and move nr into register.
if !Isconst(nl, CTSTR) {
Igen(nl, &n3, res)
}
if !Isconst(nr, CTINT) {
p2 = Thearch.Igenindex(nr, &tmp, bounded)
Regalloc(&n1, tmp.Type, nil)
Thearch.Gmove(&tmp, &n1)
}
} else if nl.Addable {
// Generate nr first, and move &nl into register.
if !Isconst(nr, CTINT) {
p2 = Thearch.Igenindex(nr, &tmp, bounded)
Regalloc(&n1, tmp.Type, nil)
Thearch.Gmove(&tmp, &n1)
}
if !Isconst(nl, CTSTR) {
Igen(nl, &n3, res)
}
} else {
p2 = Thearch.Igenindex(nr, &tmp, bounded)
nr = &tmp
if !Isconst(nl, CTSTR) {
Igen(nl, &n3, res)
}
Regalloc(&n1, tmp.Type, nil)
Thearch.Gins(Thearch.Optoas(OAS, tmp.Type), &tmp, &n1)
}
// For fixed array we really want the pointer in n3.
var n2 Node
if nl.Type.IsArray() {
Regalloc(&n2, Types[Tptr], &n3)
Agen(&n3, &n2)
Regfree(&n3)
n3 = n2
}
// &a[0] is in n3 (allocated in res)
// i is in n1 (if not constant)
// len(a) is in nlen (if needed)
// w is width
// constant index
if Isconst(nr, CTINT) {
if Isconst(nl, CTSTR) {
Fatalf("constant string constant index") // front end should handle
}
v := uint64(nr.Int64())
if nl.Type.IsSlice() || nl.Type.IsString() {
if Debug['B'] == 0 && !n.Bounded {
nlen := n3
nlen.Type = Types[TUINT32]
nlen.Xoffset += int64(Array_nel)
Nodconst(&n2, Types[TUINT32], int64(v))
p1 := Thearch.Ginscmp(OGT, Types[TUINT32], &nlen, &n2, +1)
Ginscall(Panicindex, -1)
Patch(p1, Pc)
}
}
// Load base pointer in n2 = n3.
Regalloc(&n2, Types[Tptr], &n3)
n3.Type = Types[Tptr]
n3.Xoffset += int64(Array_array)
Thearch.Gmove(&n3, &n2)
Regfree(&n3)
if v*uint64(w) != 0 {
Nodconst(&n1, Types[Tptr], int64(v*uint64(w)))
Thearch.Gins(Thearch.Optoas(OADD, Types[Tptr]), &n1, &n2)
}
*a = n2
break
}
// i is in register n1, extend to 32 bits.
t := Types[TUINT32]
if n1.Type.IsSigned() {
t = Types[TINT32]
}
Regalloc(&n2, t, &n1) // i
Thearch.Gmove(&n1, &n2)
Regfree(&n1)
if Debug['B'] == 0 && !n.Bounded {
// check bounds
t := Types[TUINT32]
var nlen Node
if Isconst(nl, CTSTR) {
Nodconst(&nlen, t, int64(len(nl.Val().U.(string))))
} else if nl.Type.IsSlice() || nl.Type.IsString() {
nlen = n3
nlen.Type = t
nlen.Xoffset += int64(Array_nel)
} else {
Nodconst(&nlen, t, nl.Type.NumElem())
}
p1 := Thearch.Ginscmp(OLT, t, &n2, &nlen, +1)
if p2 != nil {
Patch(p2, Pc)
}
Ginscall(Panicindex, -1)
Patch(p1, Pc)
}
if Isconst(nl, CTSTR) {
Regalloc(&n3, Types[Tptr], res)
p1 := Thearch.Gins(Thearch.Optoas(OAS, Types[Tptr]), nil, &n3)
Datastring(nl.Val().U.(string), &p1.From)
p1.From.Type = obj.TYPE_ADDR
Thearch.Gins(Thearch.Optoas(OADD, n3.Type), &n2, &n3)
goto indexdone1
}
// Load base pointer in n3.
Regalloc(&tmp, Types[Tptr], &n3)
if nl.Type.IsSlice() || nl.Type.IsString() {
n3.Type = Types[Tptr]
n3.Xoffset += int64(Array_array)
Thearch.Gmove(&n3, &tmp)
}
Regfree(&n3)
n3 = tmp
if w == 0 {
// nothing to do
} else if Thearch.AddIndex != nil && Thearch.AddIndex(&n2, int64(w), &n3) {
// done by back end
} else if w == 1 {
Thearch.Gins(Thearch.Optoas(OADD, Types[Tptr]), &n2, &n3)
} else {
if w&(w-1) == 0 {
// Power of 2. Use shift.
Thearch.Ginscon(Thearch.Optoas(OLSH, Types[TUINT32]), int64(log2(uint64(w))), &n2)
} else {
// Not a power of 2. Use multiply.
Thearch.Ginscon(Thearch.Optoas(OMUL, Types[TUINT32]), int64(w), &n2)
}
Thearch.Gins(Thearch.Optoas(OADD, Types[Tptr]), &n2, &n3)
}
indexdone1:
*a = n3
Regfree(&n2)
break
}
freelen := 0
w := uint64(n.Type.Width)
// Generate the non-addressable child first.
var n3 Node
var nlen Node
var tmp Node
var n1 Node
if nr.Addable {
goto irad
}
if nl.Addable {
Cgenr(nr, &n1, nil)
if !Isconst(nl, CTSTR) {
if nl.Type.IsArray() {
Agenr(nl, &n3, res)
} else {
Igen(nl, &nlen, res)
freelen = 1
nlen.Type = Types[Tptr]
nlen.Xoffset += int64(Array_array)
Regalloc(&n3, Types[Tptr], res)
Thearch.Gmove(&nlen, &n3)
nlen.Type = Types[Simtype[TUINT]]
nlen.Xoffset += int64(Array_nel) - int64(Array_array)
}
}
goto index
}
Tempname(&tmp, nr.Type)
Cgen(nr, &tmp)
nr = &tmp
irad:
if !Isconst(nl, CTSTR) {
if nl.Type.IsArray() {
Agenr(nl, &n3, res)
} else {
if !nl.Addable {
if res != nil && res.Op == OREGISTER { // give up res, which we don't need yet.
Regfree(res)
}
// igen will need an addressable node.
var tmp2 Node
Tempname(&tmp2, nl.Type)
Cgen(nl, &tmp2)
nl = &tmp2
if res != nil && res.Op == OREGISTER { // reacquire res
Regrealloc(res)
}
}
Igen(nl, &nlen, res)
freelen = 1
nlen.Type = Types[Tptr]
nlen.Xoffset += int64(Array_array)
Regalloc(&n3, Types[Tptr], res)
Thearch.Gmove(&nlen, &n3)
nlen.Type = Types[Simtype[TUINT]]
nlen.Xoffset += int64(Array_nel) - int64(Array_array)
}
}
if !Isconst(nr, CTINT) {
Cgenr(nr, &n1, nil)
}
goto index
// &a is in &n3 (allocated in res)
// i is in &n1 (if not constant)
// len(a) is in nlen (if needed)
// w is width
// constant index
index:
if Isconst(nr, CTINT) {
if Isconst(nl, CTSTR) {
Fatalf("constant string constant index") // front end should handle
}
v := uint64(nr.Int64())
if nl.Type.IsSlice() || nl.Type.IsString() {
if Debug['B'] == 0 && !n.Bounded {
p1 := Thearch.Ginscmp(OGT, Types[Simtype[TUINT]], &nlen, Nodintconst(int64(v)), +1)
Ginscall(Panicindex, -1)
Patch(p1, Pc)
}
Regfree(&nlen)
}
if v*w != 0 {
Thearch.Ginscon(Thearch.Optoas(OADD, Types[Tptr]), int64(v*w), &n3)
}
*a = n3
break
}
// type of the index
t := Types[TUINT64]
if n1.Type.IsSigned() {
t = Types[TINT64]
}
var n2 Node
Regalloc(&n2, t, &n1) // i
Thearch.Gmove(&n1, &n2)
Regfree(&n1)
if Debug['B'] == 0 && !n.Bounded {
// check bounds
t = Types[Simtype[TUINT]]
if Is64(nr.Type) {
t = Types[TUINT64]
}
if Isconst(nl, CTSTR) {
Nodconst(&nlen, t, int64(len(nl.Val().U.(string))))
} else if nl.Type.IsSlice() || nl.Type.IsString() {
// nlen already initialized
} else {
Nodconst(&nlen, t, nl.Type.NumElem())
}
p1 := Thearch.Ginscmp(OLT, t, &n2, &nlen, +1)
Ginscall(Panicindex, -1)
Patch(p1, Pc)
}
if Isconst(nl, CTSTR) {
Regalloc(&n3, Types[Tptr], res)
p1 := Thearch.Gins(Thearch.Optoas(OAS, n3.Type), nil, &n3) // XXX was LEAQ!
Datastring(nl.Val().U.(string), &p1.From)
p1.From.Type = obj.TYPE_ADDR
Thearch.Gins(Thearch.Optoas(OADD, n3.Type), &n2, &n3)
goto indexdone
}
if w == 0 {
// nothing to do
} else if Thearch.AddIndex != nil && Thearch.AddIndex(&n2, int64(w), &n3) {
// done by back end
} else if w == 1 {
Thearch.Gins(Thearch.Optoas(OADD, Types[Tptr]), &n2, &n3)
} else {
if w&(w-1) == 0 {
// Power of 2. Use shift.
Thearch.Ginscon(Thearch.Optoas(OLSH, t), int64(log2(w)), &n2)
} else {
// Not a power of 2. Use multiply.
Thearch.Ginscon(Thearch.Optoas(OMUL, t), int64(w), &n2)
}
Thearch.Gins(Thearch.Optoas(OADD, Types[Tptr]), &n2, &n3)
}
indexdone:
*a = n3
Regfree(&n2)
if freelen != 0 {
Regfree(&nlen)
}
default:
Regalloc(a, Types[Tptr], res)
Agen(n, a)
}
}
// log2 returns the logarithm base 2 of n. n must be a power of 2.
func log2(n uint64) int {
x := 0
for n>>uint(x) != 1 {
x++
}
return x
}
// generate:
// res = &n;
// The generated code checks that the result is not nil.
func Agen(n *Node, res *Node) {
if Debug['g'] != 0 {
Dump("\nagen-res", res)
Dump("agen-r", n)
}
if n == nil || n.Type == nil {
return
}
for n.Op == OCONVNOP {
n = n.Left
}
if Isconst(n, CTNIL) && n.Type.Width > int64(Widthptr) {
// Use of a nil interface or nil slice.
// Create a temporary we can take the address of and read.
// The generated code is just going to panic, so it need not
// be terribly efficient. See issue 3670.
var n1 Node
Tempname(&n1, n.Type)
Gvardef(&n1)
Thearch.Clearfat(&n1)
var n2 Node
Regalloc(&n2, Types[Tptr], res)
var n3 Node
n3.Op = OADDR
n3.Left = &n1
Thearch.Gins(Thearch.Optoas(OAS, Types[Tptr]), &n3, &n2)
Thearch.Gmove(&n2, res)
Regfree(&n2)
return
}
if n.Op == OINDREG && n.Xoffset == 0 {
// Generate MOVW R0, R1 instead of MOVW $0(R0), R1.
// This allows better move propagation in the back ends
// (and maybe it helps the processor).
n1 := *n
n1.Op = OREGISTER
n1.Type = res.Type
Thearch.Gmove(&n1, res)
return
}
if n.Addable {
if n.Op == OREGISTER {
Fatalf("agen OREGISTER")
}
var n1 Node
n1.Op = OADDR
n1.Left = n
var n2 Node
Regalloc(&n2, Types[Tptr], res)
Thearch.Gins(Thearch.Optoas(OAS, Types[Tptr]), &n1, &n2)
Thearch.Gmove(&n2, res)
Regfree(&n2)
return
}
nl := n.Left
switch n.Op {
default:
Fatalf("agen: unknown op %v", Nconv(n, FmtShort|FmtSign))
case OCALLMETH:
cgen_callmeth(n, 0)
cgen_aret(n, res)
case OCALLINTER:
cgen_callinter(n, res, 0)
cgen_aret(n, res)
case OCALLFUNC:
cgen_call(n, 0)
cgen_aret(n, res)
case OEFACE, ODOTTYPE, OSLICE, OSLICEARR, OSLICESTR, OSLICE3, OSLICE3ARR:
var n1 Node
Tempname(&n1, n.Type)
Cgen(n, &n1)
Agen(&n1, res)
case OINDEX:
var n1 Node
Agenr(n, &n1, res)
Thearch.Gmove(&n1, res)
Regfree(&n1)
case ONAME:
// should only get here with names in this func.
if n.Name.Funcdepth > 0 && n.Name.Funcdepth != Funcdepth {
Dump("bad agen", n)
Fatalf("agen: bad ONAME funcdepth %d != %d", n.Name.Funcdepth, Funcdepth)
}
// should only get here for heap vars or paramref
if n.Class&PHEAP == 0 && n.Class != PPARAMREF {
Dump("bad agen", n)
Fatalf("agen: bad ONAME class %#x", n.Class)
}
Cgen(n.Name.Heapaddr, res)
if n.Xoffset != 0 {
addOffset(res, n.Xoffset)
}
case OIND:
Cgen(nl, res)
Cgen_checknil(res)
case ODOT:
Agen(nl, res)
if n.Xoffset != 0 {
addOffset(res, n.Xoffset)
}
case ODOTPTR:
Cgen(nl, res)
Cgen_checknil(res)
if n.Xoffset != 0 {
addOffset(res, n.Xoffset)
}
}
}
func addOffset(res *Node, offset int64) {
if Ctxt.Arch.InFamily(sys.AMD64, sys.I386) {
Thearch.Gins(Thearch.Optoas(OADD, Types[Tptr]), Nodintconst(offset), res)
return
}
var n1, n2 Node
Regalloc(&n1, Types[Tptr], nil)
Thearch.Gmove(res, &n1)
Regalloc(&n2, Types[Tptr], nil)
Thearch.Gins(Thearch.Optoas(OAS, Types[Tptr]), Nodintconst(offset), &n2)
Thearch.Gins(Thearch.Optoas(OADD, Types[Tptr]), &n2, &n1)
Thearch.Gmove(&n1, res)
Regfree(&n1)
Regfree(&n2)
}
// Igen computes the address &n, stores it in a register r,
// and rewrites a to refer to *r. The chosen r may be the
// stack pointer, it may be borrowed from res, or it may
// be a newly allocated register. The caller must call Regfree(a)
// to free r when the address is no longer needed.
// The generated code ensures that &n is not nil.
func Igen(n *Node, a *Node, res *Node) {
if Debug['g'] != 0 {
Dump("\nigen-n", n)
}
switch n.Op {
case ONAME:
if (n.Class&PHEAP != 0) || n.Class == PPARAMREF {
break
}
*a = *n
return
case OINDREG:
// Increase the refcount of the register so that igen's caller
// has to call Regfree.
if n.Reg != int16(Thearch.REGSP) {
reg[n.Reg-int16(Thearch.REGMIN)]++
}
*a = *n
return
case ODOT:
Igen(n.Left, a, res)
a.Xoffset += n.Xoffset
a.Type = n.Type
Fixlargeoffset(a)
return
case ODOTPTR:
Cgenr(n.Left, a, res)
Cgen_checknil(a)
a.Op = OINDREG
a.Xoffset += n.Xoffset
a.Type = n.Type
Fixlargeoffset(a)
return
case OCALLFUNC, OCALLMETH, OCALLINTER:
switch n.Op {
case OCALLFUNC:
cgen_call(n, 0)
case OCALLMETH:
cgen_callmeth(n, 0)
case OCALLINTER:
cgen_callinter(n, nil, 0)
}
fp := n.Left.Type.Results().Field(0)
*a = Node{}
a.Op = OINDREG
a.Reg = int16(Thearch.REGSP)
a.Addable = true
a.Xoffset = fp.Offset + Ctxt.FixedFrameSize()
a.Type = n.Type
return
// Index of fixed-size array by constant can
// put the offset in the addressing.
// Could do the same for slice except that we need
// to use the real index for the bounds checking.
case OINDEX:
if n.Left.Type.IsArray() || (n.Left.Type.IsPtr() && n.Left.Left.Type.IsArray()) {
if Isconst(n.Right, CTINT) {
// Compute &a.
if !n.Left.Type.IsPtr() {
Igen(n.Left, a, res)
} else {
var n1 Node
Igen(n.Left, &n1, res)
Cgen_checknil(&n1)
Regalloc(a, Types[Tptr], res)
Thearch.Gmove(&n1, a)
Regfree(&n1)
a.Op = OINDREG
}
// Compute &a[i] as &a + i*width.
a.Type = n.Type
a.Xoffset += n.Right.Int64() * n.Type.Width
Fixlargeoffset(a)
return
}
}
}
Agenr(n, a, res)
a.Op = OINDREG
a.Type = n.Type
}
// Bgen generates code for branches:
//
// if n == wantTrue {
// goto to
// }
func Bgen(n *Node, wantTrue bool, likely int, to *obj.Prog) {
bgenx(n, nil, wantTrue, likely, to)
}
// Bvgen generates code for calculating boolean values:
// res = n == wantTrue
func Bvgen(n, res *Node, wantTrue bool) {
if Thearch.Ginsboolval == nil {
// Direct value generation not implemented for this architecture.
// Implement using jumps.
bvgenjump(n, res, wantTrue, true)
return
}
bgenx(n, res, wantTrue, 0, nil)
}
// bvgenjump implements boolean value generation using jumps:
// if n == wantTrue {
// res = 1
// } else {
// res = 0
// }
// geninit controls whether n's Ninit is generated.
func bvgenjump(n, res *Node, wantTrue, geninit bool) {
init := n.Ninit
if !geninit {
n.Ninit.Set(nil)
}
p1 := Gbranch(obj.AJMP, nil, 0)
p2 := Pc
Thearch.Gmove(Nodbool(true), res)
p3 := Gbranch(obj.AJMP, nil, 0)
Patch(p1, Pc)
Bgen(n, wantTrue, 0, p2)
Thearch.Gmove(Nodbool(false), res)
Patch(p3, Pc)
n.Ninit.MoveNodes(&init)
}
// bgenx is the backend for Bgen and Bvgen.
// If res is nil, it generates a branch.
// Otherwise, it generates a boolean value.
func bgenx(n, res *Node, wantTrue bool, likely int, to *obj.Prog) {
if Debug['g'] != 0 {
fmt.Printf("\nbgenx wantTrue=%t likely=%d to=%v\n", wantTrue, likely, to)
Dump("n", n)
Dump("res", res)
}
genval := res != nil
if n == nil {
n = Nodbool(true)
}
Genlist(n.Ninit)
if n.Type == nil {
n = convlit(n, Types[TBOOL])
if n.Type == nil {
return
}
}
if !n.Type.IsBoolean() {
Fatalf("bgen: bad type %v for %v", n.Type, Oconv(n.Op, 0))
}
for n.Op == OCONVNOP {
n = n.Left
Genlist(n.Ninit)
}
if Thearch.Bgen_float != nil && n.Left != nil && n.Left.Type.IsFloat() {
if genval {
bvgenjump(n, res, wantTrue, false)
return
}
Thearch.Bgen_float(n, wantTrue, likely, to)
return
}
switch n.Op {
default:
if genval {
Cgen(n, res)
if !wantTrue {
Thearch.Gins(Thearch.Optoas(OXOR, Types[TUINT8]), Nodintconst(1), res)
}
return
}
var tmp Node
Regalloc(&tmp, n.Type, nil)
Cgen(n, &tmp)
bgenNonZero(&tmp, nil, wantTrue, likely, to)
Regfree(&tmp)
return
case ONAME:
// Some architectures might need a temporary or other help here,
// but they don't support direct generation of a bool value yet.
// We can fix that as we go.
mayNeedTemp := Ctxt.Arch.InFamily(sys.ARM, sys.ARM64, sys.MIPS64, sys.PPC64, sys.S390X)
if genval {
if mayNeedTemp {
Fatalf("genval ONAMES not fully implemented")
}
Cgen(n, res)
if !wantTrue {
Thearch.Gins(Thearch.Optoas(OXOR, Types[TUINT8]), Nodintconst(1), res)
}
return
}
if n.Addable && !mayNeedTemp {
// no need for a temporary
bgenNonZero(n, nil, wantTrue, likely, to)
return
}
var tmp Node
Regalloc(&tmp, n.Type, nil)
Cgen(n, &tmp)
bgenNonZero(&tmp, nil, wantTrue, likely, to)
Regfree(&tmp)
return
case OLITERAL:
// n is a constant.
if !Isconst(n, CTBOOL) {
Fatalf("bgen: non-bool const %v\n", Nconv(n, FmtLong))
}
if genval {
Cgen(Nodbool(wantTrue == n.Val().U.(bool)), res)
return
}
// If n == wantTrue, jump; otherwise do nothing.
if wantTrue == n.Val().U.(bool) {
Patch(Gbranch(obj.AJMP, nil, likely), to)
}
return
case OANDAND, OOROR:
and := (n.Op == OANDAND) == wantTrue
if genval {
p1 := Gbranch(obj.AJMP, nil, 0)
p2 := Gbranch(obj.AJMP, nil, 0)
Patch(p2, Pc)
Cgen(Nodbool(!and), res)
p3 := Gbranch(obj.AJMP, nil, 0)
Patch(p1, Pc)
Bgen(n.Left, wantTrue != and, 0, p2)
Bvgen(n.Right, res, wantTrue)
Patch(p3, Pc)
return
}
if and {
p1 := Gbranch(obj.AJMP, nil, 0)
p2 := Gbranch(obj.AJMP, nil, 0)
Patch(p1, Pc)
Bgen(n.Left, !wantTrue, -likely, p2)
Bgen(n.Right, !wantTrue, -likely, p2)
p1 = Gbranch(obj.AJMP, nil, 0)
Patch(p1, to)
Patch(p2, Pc)
} else {
Bgen(n.Left, wantTrue, likely, to)
Bgen(n.Right, wantTrue, likely, to)
}
return
case ONOT: // unary
if n.Left == nil || n.Left.Type == nil {
return
}
bgenx(n.Left, res, !wantTrue, likely, to)
return
case OEQ, ONE, OLT, OGT, OLE, OGE:
if n.Left == nil || n.Left.Type == nil || n.Right == nil || n.Right.Type == nil {
return
}
}
// n.Op is one of OEQ, ONE, OLT, OGT, OLE, OGE
nl := n.Left
nr := n.Right
op := n.Op
if !wantTrue {
if nr.Type.IsFloat() {
// Brcom is not valid on floats when NaN is involved.
ll := n.Ninit // avoid re-genning Ninit
n.Ninit.Set(nil)
if genval {
bgenx(n, res, true, likely, to)
Thearch.Gins(Thearch.Optoas(OXOR, Types[TUINT8]), Nodintconst(1), res) // res = !res
n.Ninit.Set(ll.Slice())
return
}
p1 := Gbranch(obj.AJMP, nil, 0)
p2 := Gbranch(obj.AJMP, nil, 0)
Patch(p1, Pc)
bgenx(n, res, true, -likely, p2)
Patch(Gbranch(obj.AJMP, nil, 0), to)
Patch(p2, Pc)
n.Ninit.Set(ll.Slice())
return
}
op = Brcom(op)
}
wantTrue = true
// make simplest on right
if nl.Op == OLITERAL || (nl.Ullman < nr.Ullman && nl.Ullman < UINF) {
op = Brrev(op)
nl, nr = nr, nl
}
if nl.Type.IsSlice() || nl.Type.IsInterface() {
// front end should only leave cmp to literal nil
if (op != OEQ && op != ONE) || nr.Op != OLITERAL {
if nl.Type.IsSlice() {
Yyerror("illegal slice comparison")
} else {
Yyerror("illegal interface comparison")
}
return
}
var ptr Node
Igen(nl, &ptr, nil)
if nl.Type.IsSlice() {
ptr.Xoffset += int64(Array_array)
}
ptr.Type = Types[Tptr]
var tmp Node
Regalloc(&tmp, ptr.Type, &ptr)
Cgen(&ptr, &tmp)
Regfree(&ptr)
bgenNonZero(&tmp, res, op == OEQ != wantTrue, likely, to)
Regfree(&tmp)
return
}
if nl.Type.IsComplex() {
complexbool(op, nl, nr, res, wantTrue, likely, to)
return
}
if Ctxt.Arch.RegSize == 4 && Is64(nr.Type) {
if genval {
// TODO: Teach Cmp64 to generate boolean values and remove this.
bvgenjump(n, res, wantTrue, false)
return
}
if !nl.Addable || Isconst(nl, CTINT) {
nl = CgenTemp(nl)
}
if !nr.Addable {
nr = CgenTemp(nr)
}
Thearch.Cmp64(nl, nr, op, likely, to)
return
}
if nr.Ullman >= UINF {
var n1 Node
Regalloc(&n1, nl.Type, nil)
Cgen(nl, &n1)
nl = &n1
var tmp Node
Tempname(&tmp, nl.Type)
Thearch.Gmove(&n1, &tmp)
Regfree(&n1)
var n2 Node
Regalloc(&n2, nr.Type, nil)
Cgen(nr, &n2)
nr = &n2
Regalloc(&n1, nl.Type, nil)
Cgen(&tmp, &n1)
Regfree(&n1)
Regfree(&n2)
} else {
var n1 Node
if !nl.Addable && Ctxt.Arch.Family == sys.I386 {
Tempname(&n1, nl.Type)
} else {
Regalloc(&n1, nl.Type, nil)
defer Regfree(&n1)
}
Cgen(nl, &n1)
nl = &n1
if Smallintconst(nr) && Ctxt.Arch.Family != sys.MIPS64 && Ctxt.Arch.Family != sys.PPC64 {
Thearch.Gins(Thearch.Optoas(OCMP, nr.Type), nl, nr)
bins(nr.Type, res, op, likely, to)
return
}
if !nr.Addable && Ctxt.Arch.Family == sys.I386 {
nr = CgenTemp(nr)
}
var n2 Node
Regalloc(&n2, nr.Type, nil)
Cgen(nr, &n2)
nr = &n2
Regfree(&n2)
}
l, r := nl, nr
// On x86, only < and <= work right with NaN; reverse if needed
if Ctxt.Arch.Family == sys.AMD64 && nl.Type.IsFloat() && (op == OGT || op == OGE) {
l, r = r, l
op = Brrev(op)
}
// MIPS does not have CMP instruction
if Ctxt.Arch.Family == sys.MIPS64 {
p := Thearch.Ginscmp(op, nr.Type, l, r, likely)
Patch(p, to)
return
}
// Do the comparison.
Thearch.Gins(Thearch.Optoas(OCMP, nr.Type), l, r)
// Handle floating point special cases.
// Note that 8g has Bgen_float and is handled above.
if nl.Type.IsFloat() {
switch Ctxt.Arch.Family {
case sys.ARM:
if genval {
Fatalf("genval 5g Isfloat special cases not implemented")
}
switch n.Op {
case ONE:
Patch(Gbranch(Thearch.Optoas(OPS, nr.Type), nr.Type, likely), to)
Patch(Gbranch(Thearch.Optoas(op, nr.Type), nr.Type, likely), to)
default:
p := Gbranch(Thearch.Optoas(OPS, nr.Type), nr.Type, -likely)
Patch(Gbranch(Thearch.Optoas(op, nr.Type), nr.Type, likely), to)
Patch(p, Pc)
}
return
case sys.AMD64:
switch n.Op {
case OEQ:
// neither NE nor P
if genval {
var reg Node
Regalloc(&reg, Types[TBOOL], nil)
Thearch.Ginsboolval(Thearch.Optoas(OEQ, nr.Type), &reg)
Thearch.Ginsboolval(Thearch.Optoas(OPC, nr.Type), res)
Thearch.Gins(Thearch.Optoas(OAND, Types[TBOOL]), &reg, res)
Regfree(&reg)
} else {
p1 := Gbranch(Thearch.Optoas(ONE, nr.Type), nil, -likely)
p2 := Gbranch(Thearch.Optoas(OPS, nr.Type), nil, -likely)
Patch(Gbranch(obj.AJMP, nil, 0), to)
Patch(p1, Pc)
Patch(p2, Pc)
}
return
case ONE:
// either NE or P
if genval {
var reg Node
Regalloc(&reg, Types[TBOOL], nil)
Thearch.Ginsboolval(Thearch.Optoas(ONE, nr.Type), &reg)
Thearch.Ginsboolval(Thearch.Optoas(OPS, nr.Type), res)
Thearch.Gins(Thearch.Optoas(OOR, Types[TBOOL]), &reg, res)
Regfree(&reg)
} else {
Patch(Gbranch(Thearch.Optoas(ONE, nr.Type), nil, likely), to)
Patch(Gbranch(Thearch.Optoas(OPS, nr.Type), nil, likely), to)
}
return
}
case sys.ARM64, sys.PPC64:
if genval {
Fatalf("genval 7g, 9g Isfloat special cases not implemented")
}
switch n.Op {
// On arm64 and ppc64, <= and >= mishandle NaN. Must decompose into < or > and =.
// TODO(josh): Convert a <= b to b > a instead?
case OLE, OGE:
if op == OLE {
op = OLT
} else {
op = OGT
}
Patch(Gbranch(Thearch.Optoas(op, nr.Type), nr.Type, likely), to)
Patch(Gbranch(Thearch.Optoas(OEQ, nr.Type), nr.Type, likely), to)
return
}
}
}
// Not a special case. Insert the conditional jump or value gen.
bins(nr.Type, res, op, likely, to)
}
func bgenNonZero(n, res *Node, wantTrue bool, likely int, to *obj.Prog) {
// TODO: Optimize on systems that can compare to zero easily.
var op Op = ONE
if !wantTrue {
op = OEQ
}
// MIPS does not have CMP instruction
if Thearch.LinkArch.Family == sys.MIPS64 {
p := Gbranch(Thearch.Optoas(op, n.Type), n.Type, likely)
Naddr(&p.From, n)
Patch(p, to)
return
}
var zero Node
Nodconst(&zero, n.Type, 0)
Thearch.Gins(Thearch.Optoas(OCMP, n.Type), n, &zero)
bins(n.Type, res, op, likely, to)
}
// bins inserts an instruction to handle the result of a compare.
// If res is non-nil, it inserts appropriate value generation instructions.
// If res is nil, it inserts a branch to to.
func bins(typ *Type, res *Node, op Op, likely int, to *obj.Prog) {
a := Thearch.Optoas(op, typ)
if res != nil {
// value gen
Thearch.Ginsboolval(a, res)
} else {
// jump
Patch(Gbranch(a, typ, likely), to)
}
}
// stkof returns n's offset from SP if n is on the stack
// (either a local variable or the return value from a function call
// or the arguments to a function call).
// If n is not on the stack, stkof returns -1000.
// If n is on the stack but in an unknown location
// (due to array index arithmetic), stkof returns +1000.
//
// NOTE(rsc): It is possible that the ODOT and OINDEX cases
// are not relevant here, since it shouldn't be possible for them
// to be involved in an overlapping copy. Only function results
// from one call and the arguments to the next can overlap in
// any non-trivial way. If they can be dropped, then this function
// becomes much simpler and also more trustworthy.
// The fact that it works at all today is probably due to the fact
// that ODOT and OINDEX are irrelevant.
func stkof(n *Node) int64 {
switch n.Op {
case OINDREG:
if n.Reg != int16(Thearch.REGSP) {
return -1000 // not on stack
}
return n.Xoffset
case ODOT:
t := n.Left.Type
if t.IsPtr() {
break
}
off := stkof(n.Left)
if off == -1000 || off == +1000 {
return off
}
return off + n.Xoffset
case OINDEX:
t := n.Left.Type
if !t.IsArray() {
break
}
off := stkof(n.Left)
if off == -1000 || off == +1000 {
return off
}
if Isconst(n.Right, CTINT) {
return off + t.Elem().Width*n.Right.Int64()
}
return +1000 // on stack but not sure exactly where
case OCALLMETH, OCALLINTER, OCALLFUNC:
t := n.Left.Type
if t.IsPtr() {
t = t.Elem()
}
f := t.Results().Field(0)
if f != nil {
return f.Offset + Ctxt.FixedFrameSize()
}
}
// botch - probably failing to recognize address
// arithmetic on the above. eg INDEX and DOT
return -1000 // not on stack
}
// block copy:
// memmove(&ns, &n, w);
// if wb is true, needs write barrier.
func sgen_wb(n *Node, ns *Node, w int64, wb bool) {
if Debug['g'] != 0 {
op := "sgen"
if wb {
op = "sgen-wb"
}
fmt.Printf("\n%s w=%d\n", op, w)
Dump("r", n)
Dump("res", ns)
}
if n.Ullman >= UINF && ns.Ullman >= UINF {
Fatalf("sgen UINF")
}
if w < 0 {
Fatalf("sgen copy %d", w)
}
// If copying .args, that's all the results, so record definition sites
// for them for the liveness analysis.
if ns.Op == ONAME && ns.Sym.Name == ".args" {
for _, ln := range Curfn.Func.Dcl {
if ln.Class == PPARAMOUT {
Gvardef(ln)
}
}
}
// Avoid taking the address for simple enough types.
if componentgen_wb(n, ns, wb) {
return
}
if w == 0 {
// evaluate side effects only
var nodr Node
Regalloc(&nodr, Types[Tptr], nil)
Agen(ns, &nodr)
Agen(n, &nodr)
Regfree(&nodr)
return
}
// offset on the stack
osrc := stkof(n)
odst := stkof(ns)
if odst != -1000 {
// on stack, write barrier not needed after all
wb = false
}
if osrc != -1000 && odst != -1000 && (osrc == 1000 || odst == 1000) || wb && osrc != -1000 {
// osrc and odst both on stack, and at least one is in
// an unknown position. Could generate code to test
// for forward/backward copy, but instead just copy
// to a temporary location first.
//
// OR: write barrier needed and source is on stack.
// Invoking the write barrier will use the stack to prepare its call.
// Copy to temporary.
var tmp Node
Tempname(&tmp, n.Type)
sgen_wb(n, &tmp, w, false)
sgen_wb(&tmp, ns, w, wb)
return
}
if wb {
cgen_wbfat(n, ns)
return
}
Thearch.Blockcopy(n, ns, osrc, odst, w)
}
// generate:
// call f
// proc=-1 normal call but no return
// proc=0 normal call
// proc=1 goroutine run in new proc
// proc=2 defer call save away stack
// proc=3 normal call to C pointer (not Go func value)
func Ginscall(f *Node, proc int) {
if f.Type != nil {
extra := int32(0)
if proc == 1 || proc == 2 {
extra = 2 * int32(Widthptr)
}
Setmaxarg(f.Type, extra)
}
switch proc {
default:
Fatalf("Ginscall: bad proc %d", proc)
case 0, // normal call
-1: // normal call but no return
if f.Op == ONAME && f.Class == PFUNC {
if f == Deferreturn {
// Deferred calls will appear to be returning to the CALL
// deferreturn(SB) that we are about to emit. However, the
// stack scanning code will think that the instruction
// before the CALL is executing. To avoid the scanning
// code making bad assumptions (both cosmetic such as
// showing the wrong line number and fatal, such as being
// confused over whether a stack slot contains a pointer
// or a scalar) insert an actual hardware NOP that will
// have the right line number. This is different from
// obj.ANOP, which is a virtual no-op that doesn't make it
// into the instruction stream.
Thearch.Ginsnop()
if Thearch.LinkArch.Family == sys.PPC64 {
// On ppc64, when compiling Go into position
// independent code on ppc64le we insert an
// instruction to reload the TOC pointer from the
// stack as well. See the long comment near
// jmpdefer in runtime/asm_ppc64.s for why.
// If the MOVD is not needed, insert a hardware NOP
// so that the same number of instructions are used
// on ppc64 in both shared and non-shared modes.
if Ctxt.Flag_shared {
p := Thearch.Gins(ppc64.AMOVD, nil, nil)
p.From.Type = obj.TYPE_MEM
p.From.Offset = 24
p.From.Reg = ppc64.REGSP
p.To.Type = obj.TYPE_REG
p.To.Reg = ppc64.REG_R2
} else {
Thearch.Ginsnop()
}
}
}
p := Thearch.Gins(obj.ACALL, nil, f)
Afunclit(&p.To, f)
if proc == -1 || Noreturn(p) {
Thearch.Gins(obj.AUNDEF, nil, nil)
}
break
}
var reg Node
Nodreg(&reg, Types[Tptr], Thearch.REGCTXT)
var r1 Node
Nodreg(&r1, Types[Tptr], Thearch.REGCALLX)
Thearch.Gmove(f, &reg)
reg.Op = OINDREG
Thearch.Gmove(&reg, &r1)
reg.Op = OREGISTER
Thearch.Gins(obj.ACALL, &reg, &r1)
case 3: // normal call of c function pointer
Thearch.Gins(obj.ACALL, nil, f)
case 1, // call in new proc (go)
2: // deferred call (defer)
var stk Node
// size of arguments at 0(SP)
stk.Op = OINDREG
stk.Reg = int16(Thearch.REGSP)
stk.Xoffset = Ctxt.FixedFrameSize()
Thearch.Ginscon(Thearch.Optoas(OAS, Types[TINT32]), int64(Argsize(f.Type)), &stk)
// FuncVal* at 8(SP)
stk.Xoffset = int64(Widthptr) + Ctxt.FixedFrameSize()
var reg Node
Nodreg(&reg, Types[Tptr], Thearch.REGCALLX2)
Thearch.Gmove(f, &reg)
Thearch.Gins(Thearch.Optoas(OAS, Types[Tptr]), &reg, &stk)
if proc == 1 {
Ginscall(Newproc, 0)
} else {
if !hasdefer {
Fatalf("hasdefer=0 but has defer")
}
Ginscall(Deferproc, 0)
}
if proc == 2 {
Nodreg(&reg, Types[TINT32], Thearch.REGRETURN)
p := Thearch.Ginscmp(OEQ, Types[TINT32], &reg, Nodintconst(0), +1)
cgen_ret(nil)
Patch(p, Pc)
}
}
}
// n is call to interface method.
// generate res = n.
func cgen_callinter(n *Node, res *Node, proc int) {
i := n.Left
if i.Op != ODOTINTER {
Fatalf("cgen_callinter: not ODOTINTER %v", Oconv(i.Op, 0))
}
i = i.Left // interface
if !i.Addable {
var tmpi Node
Tempname(&tmpi, i.Type)
Cgen(i, &tmpi)
i = &tmpi
}
Genlist(n.List) // assign the args
// i is now addable, prepare an indirected
// register to hold its address.
var nodi Node
Igen(i, &nodi, res) // REG = &inter
var nodsp Node
Nodindreg(&nodsp, Types[Tptr], Thearch.REGSP)
nodsp.Xoffset = Ctxt.FixedFrameSize()
if proc != 0 {
nodsp.Xoffset += 2 * int64(Widthptr) // leave room for size & fn
}
nodi.Type = Types[Tptr]
nodi.Xoffset += int64(Widthptr)
Cgen(&nodi, &nodsp) // {0, 8(nacl), or 16}(SP) = 8(REG) -- i.data
var nodo Node
Regalloc(&nodo, Types[Tptr], res)
nodi.Type = Types[Tptr]
nodi.Xoffset -= int64(Widthptr)
Cgen(&nodi, &nodo) // REG = 0(REG) -- i.tab
Regfree(&nodi)
var nodr Node
Regalloc(&nodr, Types[Tptr], &nodo)
if n.Left.Xoffset == BADWIDTH {
Fatalf("cgen_callinter: badwidth")
}
Cgen_checknil(&nodo) // in case offset is huge
nodo.Op = OINDREG
nodo.Xoffset = n.Left.Xoffset + 3*int64(Widthptr) + 8
if proc == 0 {
// plain call: use direct c function pointer - more efficient
Cgen(&nodo, &nodr) // REG = 32+offset(REG) -- i.tab->fun[f]
proc = 3
} else {
// go/defer. generate go func value.
Agen(&nodo, &nodr) // REG = &(32+offset(REG)) -- i.tab->fun[f]
}
nodr.Type = n.Left.Type
Ginscall(&nodr, proc)
Regfree(&nodr)
Regfree(&nodo)
}
// generate function call;
// proc=0 normal call
// proc=1 goroutine run in new proc
// proc=2 defer call save away stack
func cgen_call(n *Node, proc int) {
if n == nil {
return
}
var afun Node
if n.Left.Ullman >= UINF {
// if name involves a fn call
// precompute the address of the fn
Tempname(&afun, Types[Tptr])
Cgen(n.Left, &afun)
}
Genlist(n.List) // assign the args
t := n.Left.Type
// call tempname pointer
if n.Left.Ullman >= UINF {
var nod Node
Regalloc(&nod, Types[Tptr], nil)
Cgen_as(&nod, &afun)
nod.Type = t
Ginscall(&nod, proc)
Regfree(&nod)
return
}
// call pointer
if n.Left.Op != ONAME || n.Left.Class != PFUNC {
var nod Node
Regalloc(&nod, Types[Tptr], nil)
Cgen_as(&nod, n.Left)
nod.Type = t
Ginscall(&nod, proc)
Regfree(&nod)
return
}
// call direct
n.Left.Name.Method = true
Ginscall(n.Left, proc)
}
// call to n has already been generated.
// generate:
// res = return value from call.
func cgen_callret(n *Node, res *Node) {
t := n.Left.Type
if t.Etype == TPTR32 || t.Etype == TPTR64 {
t = t.Elem()
}
fp := t.Results().Field(0)
if fp == nil {
Fatalf("cgen_callret: nil")
}
var nod Node
nod.Op = OINDREG
nod.Reg = int16(Thearch.REGSP)
nod.Addable = true
nod.Xoffset = fp.Offset + Ctxt.FixedFrameSize()
nod.Type = fp.Type
Cgen_as(res, &nod)
}
// call to n has already been generated.
// generate:
// res = &return value from call.
func cgen_aret(n *Node, res *Node) {
t := n.Left.Type
if t.IsPtr() {
t = t.Elem()
}
fp := t.Results().Field(0)
if fp == nil {
Fatalf("cgen_aret: nil")
}
var nod1 Node
nod1.Op = OINDREG
nod1.Reg = int16(Thearch.REGSP)
nod1.Addable = true
nod1.Xoffset = fp.Offset + Ctxt.FixedFrameSize()
nod1.Type = fp.Type
if res.Op != OREGISTER {
var nod2 Node
Regalloc(&nod2, Types[Tptr], res)
Agen(&nod1, &nod2)
Thearch.Gins(Thearch.Optoas(OAS, Types[Tptr]), &nod2, res)
Regfree(&nod2)
} else {
Agen(&nod1, res)
}
}
// generate return.
// n->left is assignments to return values.
func cgen_ret(n *Node) {
if n != nil {
Genlist(n.List) // copy out args
}
if hasdefer {
Ginscall(Deferreturn, 0)
}
Genlist(Curfn.Func.Exit)
p := Thearch.Gins(obj.ARET, nil, nil)
if n != nil && n.Op == ORETJMP {
p.To.Type = obj.TYPE_MEM
p.To.Name = obj.NAME_EXTERN
p.To.Sym = Linksym(n.Left.Sym)
}
}
// hasHMUL64 reports whether the architecture supports 64-bit
// signed and unsigned high multiplication (OHMUL).
func hasHMUL64() bool {
switch Ctxt.Arch.Family {
case sys.AMD64, sys.S390X:
return true
case sys.ARM, sys.ARM64, sys.I386, sys.MIPS64, sys.PPC64:
return false
}
Fatalf("unknown architecture")
return false
}
// hasRROTC64 reports whether the architecture supports 64-bit
// rotate through carry instructions (ORROTC).
func hasRROTC64() bool {
switch Ctxt.Arch.Family {
case sys.AMD64:
return true
case sys.ARM, sys.ARM64, sys.I386, sys.MIPS64, sys.PPC64, sys.S390X:
return false
}
Fatalf("unknown architecture")
return false
}
// generate division according to op, one of:
// res = nl / nr
// res = nl % nr
func cgen_div(op Op, nl *Node, nr *Node, res *Node) {
var w int
// Architectures need to support 64-bit high multiplications
// (OHMUL) in order to perform divide by constant optimizations.
if nr.Op != OLITERAL || !hasHMUL64() {
goto longdiv
}
w = int(nl.Type.Width * 8)
// Front end handled 32-bit division. We only need to handle 64-bit.
// Try to do division using multiplication: (2^w)/d.
// See Hacker's Delight, chapter 10.
switch Simtype[nl.Type.Etype] {
default:
goto longdiv
case TUINT64:
var m Magic
m.W = w
m.Ud = uint64(nr.Int64())
Umagic(&m)
if m.Bad != 0 {
break
}
// In order to add the numerator we need to be able to
// avoid overflow. This is done by shifting the result of the
// addition right by 1 and inserting the carry bit into
// the MSB. For now this needs the RROTC instruction.
// TODO(mundaym): Hacker's Delight 2nd ed. chapter 10 proposes
// an alternative sequence of instructions for architectures
// that do not have a shift right with carry instruction.
if m.Ua != 0 && !hasRROTC64() {
goto longdiv
}
if op == OMOD {
goto longmod
}
var n1 Node
Cgenr(nl, &n1, nil)
var n2 Node
Nodconst(&n2, nl.Type, int64(m.Um))
var n3 Node
Regalloc(&n3, nl.Type, res)
Thearch.Cgen_hmul(&n1, &n2, &n3)
if m.Ua != 0 {
// Need to add numerator accounting for overflow.
Thearch.Gins(Thearch.Optoas(OADD, nl.Type), &n1, &n3)
Nodconst(&n2, nl.Type, 1)
Thearch.Gins(Thearch.Optoas(ORROTC, nl.Type), &n2, &n3)
Nodconst(&n2, nl.Type, int64(m.S)-1)
Thearch.Gins(Thearch.Optoas(ORSH, nl.Type), &n2, &n3)
} else {
Nodconst(&n2, nl.Type, int64(m.S))
Thearch.Gins(Thearch.Optoas(ORSH, nl.Type), &n2, &n3) // shift dx
}
Thearch.Gmove(&n3, res)
Regfree(&n1)
Regfree(&n3)
return
case TINT64:
var m Magic
m.W = w
m.Sd = nr.Int64()
Smagic(&m)
if m.Bad != 0 {
break
}
if op == OMOD {
goto longmod
}
var n1 Node
Cgenr(nl, &n1, res)
var n2 Node
Nodconst(&n2, nl.Type, m.Sm)
var n3 Node
Regalloc(&n3, nl.Type, nil)
Thearch.Cgen_hmul(&n1, &n2, &n3)
if m.Sm < 0 {
// Need to add numerator (cannot overflow).
Thearch.Gins(Thearch.Optoas(OADD, nl.Type), &n1, &n3)
}
Nodconst(&n2, nl.Type, int64(m.S))
Thearch.Gins(Thearch.Optoas(ORSH, nl.Type), &n2, &n3) // shift n3
Nodconst(&n2, nl.Type, int64(w)-1)
Thearch.Gins(Thearch.Optoas(ORSH, nl.Type), &n2, &n1) // -1 iff num is neg
Thearch.Gins(Thearch.Optoas(OSUB, nl.Type), &n1, &n3) // added
if m.Sd < 0 {
// This could probably be removed by factoring it into
// the multiplier.
Thearch.Gins(Thearch.Optoas(OMINUS, nl.Type), nil, &n3)
}
Thearch.Gmove(&n3, res)
Regfree(&n1)
Regfree(&n3)
return
}
goto longdiv
// Division and mod using (slow) hardware instruction.
longdiv:
Thearch.Dodiv(op, nl, nr, res)
return
// Mod using formula A%B = A-(A/B*B) but
// we know that there is a fast algorithm for A/B.
longmod:
var n1 Node
Regalloc(&n1, nl.Type, res)
Cgen(nl, &n1)
var n2 Node
Regalloc(&n2, nl.Type, nil)
cgen_div(ODIV, &n1, nr, &n2)
a := Thearch.Optoas(OMUL, nl.Type)
if !Smallintconst(nr) {
var n3 Node
Regalloc(&n3, nl.Type, nil)
Cgen(nr, &n3)
Thearch.Gins(a, &n3, &n2)
Regfree(&n3)
} else {
Thearch.Gins(a, nr, &n2)
}
Thearch.Gins(Thearch.Optoas(OSUB, nl.Type), &n2, &n1)
Thearch.Gmove(&n1, res)
Regfree(&n1)
Regfree(&n2)
}
func Fixlargeoffset(n *Node) {
if n == nil {
return
}
if n.Op != OINDREG {
return
}
if n.Reg == int16(Thearch.REGSP) { // stack offset cannot be large
return
}
if n.Xoffset != int64(int32(n.Xoffset)) {
// offset too large, add to register instead.
a := *n
a.Op = OREGISTER
a.Type = Types[Tptr]
a.Xoffset = 0
Cgen_checknil(&a)
Thearch.Ginscon(Thearch.Optoas(OADD, Types[Tptr]), n.Xoffset, &a)
n.Xoffset = 0
}
}
func cgen_append(n, res *Node) {
if Debug['g'] != 0 {
Dump("cgen_append-n", n)
Dump("cgen_append-res", res)
}
if res.Op != ONAME && !samesafeexpr(res, n.List.First()) {
Dump("cgen_append-n", n)
Dump("cgen_append-res", res)
Fatalf("append not lowered")
}
for _, n1 := range n.List.Slice() {
if n1.Ullman >= UINF {
Fatalf("append with function call arguments")
}
}
// res = append(src, x, y, z)
//
// If res and src are the same, we can avoid writing to base and cap
// unless we grow the underlying array.
needFullUpdate := !samesafeexpr(res, n.List.First())
// Copy src triple into base, len, cap.
base := temp(Types[Tptr])
len := temp(Types[TUINT])
cap := temp(Types[TUINT])
var src Node
Igen(n.List.First(), &src, nil)
src.Type = Types[Tptr]
Thearch.Gmove(&src, base)
src.Type = Types[TUINT]
src.Xoffset += int64(Widthptr)
Thearch.Gmove(&src, len)
src.Xoffset += int64(Widthptr)
Thearch.Gmove(&src, cap)
// if len+argc <= cap goto L1
var rlen Node
Regalloc(&rlen, Types[TUINT], nil)
Thearch.Gmove(len, &rlen)
Thearch.Ginscon(Thearch.Optoas(OADD, Types[TUINT]), int64(n.List.Len()-1), &rlen)
p := Thearch.Ginscmp(OLE, Types[TUINT], &rlen, cap, +1)
// Note: rlen and src are Regrealloc'ed below at the target of the
// branch we just emitted; do not reuse these Go variables for
// other purposes. They need to still describe the same things
// below that they describe right here.
Regfree(&src)
// base, len, cap = growslice(type, base, len, cap, newlen)
var arg Node
arg.Op = OINDREG
arg.Reg = int16(Thearch.REGSP)
arg.Addable = true
arg.Xoffset = Ctxt.FixedFrameSize()
arg.Type = Ptrto(Types[TUINT8])
Cgen(typename(res.Type.Elem()), &arg)
arg.Xoffset += int64(Widthptr)
arg.Type = Types[Tptr]
Cgen(base, &arg)
arg.Xoffset += int64(Widthptr)
arg.Type = Types[TUINT]
Cgen(len, &arg)
arg.Xoffset += int64(Widthptr)
arg.Type = Types[TUINT]
Cgen(cap, &arg)
arg.Xoffset += int64(Widthptr)
arg.Type = Types[TUINT]
Cgen(&rlen, &arg)
arg.Xoffset += int64(Widthptr)
Regfree(&rlen)
fn := syslook("growslice")
fn = substArgTypes(fn, res.Type.Elem(), res.Type.Elem())
Ginscall(fn, 0)
if Widthptr == 4 && Widthreg == 8 {
arg.Xoffset += 4
}
arg.Type = Types[Tptr]
Cgen(&arg, base)
arg.Xoffset += int64(Widthptr)
arg.Type = Types[TUINT]
Cgen(&arg, len)
arg.Xoffset += int64(Widthptr)
arg.Type = Types[TUINT]
Cgen(&arg, cap)
// Update res with base, len+argc, cap.
if needFullUpdate {
if Debug_append > 0 {
Warn("append: full update")
}
Patch(p, Pc)
}
if res.Op == ONAME {
Gvardef(res)
}
var dst, r1 Node
Igen(res, &dst, nil)
dst.Type = Types[TUINT]
dst.Xoffset += int64(Widthptr)
Regalloc(&r1, Types[TUINT], nil)
Thearch.Gmove(len, &r1)
Thearch.Ginscon(Thearch.Optoas(OADD, Types[TUINT]), int64(n.List.Len()-1), &r1)
Thearch.Gmove(&r1, &dst)
Regfree(&r1)
dst.Xoffset += int64(Widthptr)
Thearch.Gmove(cap, &dst)
dst.Type = Types[Tptr]
dst.Xoffset -= 2 * int64(Widthptr)
cgen_wb(base, &dst, needwritebarrier(&dst, base))
Regfree(&dst)
if !needFullUpdate {
if Debug_append > 0 {
Warn("append: len-only update")
}
// goto L2;
// L1:
// update len only
// L2:
q := Gbranch(obj.AJMP, nil, 0)
Patch(p, Pc)
// At the goto above, src refers to cap and rlen holds the new len
if src.Op == OREGISTER || src.Op == OINDREG {
Regrealloc(&src)
}
Regrealloc(&rlen)
src.Xoffset -= int64(Widthptr)
Thearch.Gmove(&rlen, &src)
Regfree(&src)
Regfree(&rlen)
Patch(q, Pc)
}
// Copy data into place.
// Could do write barrier check around entire copy instead of each element.
// Could avoid reloading registers on each iteration if we know the cgen_wb
// is not going to use a write barrier.
i := 0
var r2 Node
for _, n2 := range n.List.Slice()[1:] {
Regalloc(&r1, Types[Tptr], nil)
Thearch.Gmove(base, &r1)
Regalloc(&r2, Types[TUINT], nil)
Thearch.Gmove(len, &r2)
if i > 0 {
Thearch.Gins(Thearch.Optoas(OADD, Types[TUINT]), Nodintconst(int64(i)), &r2)
}
w := res.Type.Elem().Width
if Thearch.AddIndex != nil && Thearch.AddIndex(&r2, w, &r1) {
// r1 updated by back end
} else if w == 1 {
Thearch.Gins(Thearch.Optoas(OADD, Types[Tptr]), &r2, &r1)
} else {
Thearch.Ginscon(Thearch.Optoas(OMUL, Types[TUINT]), w, &r2)
Thearch.Gins(Thearch.Optoas(OADD, Types[Tptr]), &r2, &r1)
}
Regfree(&r2)
r1.Op = OINDREG
r1.Type = res.Type.Elem()
cgen_wb(n2, &r1, needwritebarrier(&r1, n2))
Regfree(&r1)
i++
}
}
// Generate res = n, where n is x[i:j] or x[i:j:k].
// If wb is true, need write barrier updating res's base pointer.
// On systems with 32-bit ints, i, j, k are guaranteed to be 32-bit values.
func cgen_slice(n, res *Node, wb bool) {
if Debug['g'] != 0 {
Dump("cgen_slice-n", n)
Dump("cgen_slice-res", res)
}
needFullUpdate := !samesafeexpr(n.Left, res)
// orderexpr has made sure that x is safe (but possibly expensive)
// and i, j, k are cheap. On a system with registers (anything but 386)
// we can evaluate x first and then know we have enough registers
// for i, j, k as well.
var x, xbase, xlen, xcap, i, j, k Node
if n.Op != OSLICEARR && n.Op != OSLICE3ARR {
Igen(n.Left, &x, nil)
}
indexRegType := Types[TUINT]
if Widthreg > Widthptr { // amd64p32
indexRegType = Types[TUINT64]
}
// On most systems, we use registers.
// The 386 has basically no registers, so substitute functions
// that can work with temporaries instead.
regalloc := Regalloc
ginscon := Thearch.Ginscon
gins := Thearch.Gins
if Thearch.LinkArch.Family == sys.I386 {
regalloc = func(n *Node, t *Type, reuse *Node) {
Tempname(n, t)
}
ginscon = func(as obj.As, c int64, n *Node) {
var n1 Node
Regalloc(&n1, n.Type, n)
Thearch.Gmove(n, &n1)
Thearch.Ginscon(as, c, &n1)
Thearch.Gmove(&n1, n)
Regfree(&n1)
}
gins = func(as obj.As, f, t *Node) *obj.Prog {
var n1 Node
Regalloc(&n1, t.Type, t)
Thearch.Gmove(t, &n1)
Thearch.Gins(as, f, &n1)
Thearch.Gmove(&n1, t)
Regfree(&n1)
return nil
}
}
panics := make([]*obj.Prog, 0, 6) // 3 loads + 3 checks
loadlen := func() {
if xlen.Op != 0 {
return
}
if n.Op == OSLICEARR || n.Op == OSLICE3ARR {
Nodconst(&xlen, indexRegType, n.Left.Type.Elem().NumElem())
return
}
if n.Op == OSLICESTR && Isconst(n.Left, CTSTR) {
Nodconst(&xlen, indexRegType, int64(len(n.Left.Val().U.(string))))
return
}
regalloc(&xlen, indexRegType, nil)
x.Xoffset += int64(Widthptr)
x.Type = Types[TUINT]
Thearch.Gmove(&x, &xlen)
x.Xoffset -= int64(Widthptr)
}
loadcap := func() {
if xcap.Op != 0 {
return
}
if n.Op == OSLICEARR || n.Op == OSLICE3ARR || n.Op == OSLICESTR {
loadlen()
xcap = xlen
if xcap.Op == OREGISTER {
Regrealloc(&xcap)
}
return
}
regalloc(&xcap, indexRegType, nil)
x.Xoffset += 2 * int64(Widthptr)
x.Type = Types[TUINT]
Thearch.Gmove(&x, &xcap)
x.Xoffset -= 2 * int64(Widthptr)
}
var x1, x2, x3 *Node // unevaluated index arguments
x1 = n.Right.Left
switch n.Op {
default:
x2 = n.Right.Right
case OSLICE3, OSLICE3ARR:
x2 = n.Right.Right.Left
x3 = n.Right.Right.Right
}
// load computes src into targ, but if src refers to the len or cap of n.Left,
// load copies those from xlen, xcap, loading xlen if needed.
// If targ.Op == OREGISTER on return, it must be Regfreed,
// but it should not be modified without first checking whether it is
// xlen or xcap's register.
load := func(src, targ *Node) {
if src == nil {
return
}
switch src.Op {
case OLITERAL:
*targ = *src
return
case OLEN:
// NOTE(rsc): This doesn't actually trigger, because order.go
// has pulled all the len and cap calls into separate assignments
// to temporaries. There are tests in test/sliceopt.go that could
// be enabled if this is fixed.
if samesafeexpr(n.Left, src.Left) {
if Debug_slice > 0 {
Warn("slice: reuse len")
}
loadlen()
*targ = xlen
if targ.Op == OREGISTER {
Regrealloc(targ)
}
return
}
case OCAP:
// NOTE(rsc): This doesn't actually trigger; see note in case OLEN above.
if samesafeexpr(n.Left, src.Left) {
if Debug_slice > 0 {
Warn("slice: reuse cap")
}
loadcap()
*targ = xcap
if targ.Op == OREGISTER {
Regrealloc(targ)
}
return
}
}
if i.Op != 0 && samesafeexpr(x1, src) {
if Debug_slice > 0 {
Warn("slice: reuse 1st index")
}
*targ = i
if targ.Op == OREGISTER {
Regrealloc(targ)
}
return
}
if j.Op != 0 && samesafeexpr(x2, src) {
if Debug_slice > 0 {
Warn("slice: reuse 2nd index")
}
*targ = j
if targ.Op == OREGISTER {
Regrealloc(targ)
}
return
}
if Thearch.Cgenindex != nil {
regalloc(targ, indexRegType, nil)
p := Thearch.Cgenindex(src, targ, false)
if p != nil {
panics = append(panics, p)
}
} else if Thearch.Igenindex != nil {
p := Thearch.Igenindex(src, targ, false)
if p != nil {
panics = append(panics, p)
}
} else {
regalloc(targ, indexRegType, nil)
var tmp Node
Cgenr(src, &tmp, targ)
Thearch.Gmove(&tmp, targ)
Regfree(&tmp)
}
}
load(x1, &i)
load(x2, &j)
load(x3, &k)
// i defaults to 0.
if i.Op == 0 {
Nodconst(&i, indexRegType, 0)
}
// j defaults to len(x)
if j.Op == 0 {
loadlen()
j = xlen
if j.Op == OREGISTER {
Regrealloc(&j)
}
}
// k defaults to cap(x)
// Only need to load it if we're recalculating cap or doing a full update.
if k.Op == 0 && n.Op != OSLICESTR && (!iszero(&i) || needFullUpdate) {
loadcap()
k = xcap
if k.Op == OREGISTER {
Regrealloc(&k)
}
}
// Check constant indexes for negative values, and against constant length if known.
// The func obvious below checks for out-of-order constant indexes.
var bound int64 = -1
if n.Op == OSLICEARR || n.Op == OSLICE3ARR {
bound = n.Left.Type.Elem().NumElem()
} else if n.Op == OSLICESTR && Isconst(n.Left, CTSTR) {
bound = int64(len(n.Left.Val().U.(string)))
}
if Isconst(&i, CTINT) {
if i.Val().U.(*Mpint).CmpInt64(0) < 0 || bound >= 0 && i.Val().U.(*Mpint).CmpInt64(bound) > 0 {
Yyerror("slice index out of bounds")
}
}
if Isconst(&j, CTINT) {
if j.Val().U.(*Mpint).CmpInt64(0) < 0 || bound >= 0 && j.Val().U.(*Mpint).CmpInt64(bound) > 0 {
Yyerror("slice index out of bounds")
}
}
if Isconst(&k, CTINT) {
if k.Val().U.(*Mpint).CmpInt64(0) < 0 || bound >= 0 && k.Val().U.(*Mpint).CmpInt64(bound) > 0 {
Yyerror("slice index out of bounds")
}
}
// same reports whether n1 and n2 are the same register or constant.
same := func(n1, n2 *Node) bool {
return n1.Op == OREGISTER && n2.Op == OREGISTER && n1.Reg == n2.Reg ||
n1.Op == ONAME && n2.Op == ONAME && n1.Orig == n2.Orig && n1.Type == n2.Type && n1.Xoffset == n2.Xoffset ||
n1.Op == OLITERAL && n2.Op == OLITERAL && n1.Val().U.(*Mpint).Cmp(n2.Val().U.(*Mpint)) == 0
}
// obvious reports whether n1 <= n2 is obviously true,
// and it calls Yyerror if n1 <= n2 is obviously false.
obvious := func(n1, n2 *Node) bool {
if Debug['B'] != 0 { // -B disables bounds checks
return true
}
if same(n1, n2) {
return true // n1 == n2
}
if iszero(n1) {
return true // using unsigned compare, so 0 <= n2 always true
}
if xlen.Op != 0 && same(n1, &xlen) && xcap.Op != 0 && same(n2, &xcap) {
return true // len(x) <= cap(x) always true
}
if Isconst(n1, CTINT) && Isconst(n2, CTINT) {
if n1.Val().U.(*Mpint).Cmp(n2.Val().U.(*Mpint)) <= 0 {
return true // n1, n2 constants such that n1 <= n2
}
Yyerror("slice index out of bounds")
return true
}
return false
}
compare := func(n1, n2 *Node) {
// n1 might be a 64-bit constant, even on 32-bit architectures,
// but it will be represented in 32 bits.
if Ctxt.Arch.RegSize == 4 && Is64(n1.Type) {
if n1.Val().U.(*Mpint).CmpInt64(1<<31) >= 0 {
Fatalf("missed slice out of bounds check")
}
var tmp Node
Nodconst(&tmp, indexRegType, n1.Int64())
n1 = &tmp
}
p := Thearch.Ginscmp(OGT, indexRegType, n1, n2, -1)
panics = append(panics, p)
}
loadcap()
max := &xcap
if k.Op != 0 && (n.Op == OSLICE3 || n.Op == OSLICE3ARR) {
if obvious(&k, max) {
if Debug_slice > 0 {
Warn("slice: omit check for 3rd index")
}
} else {
compare(&k, max)
}
max = &k
}
if j.Op != 0 {
if obvious(&j, max) {
if Debug_slice > 0 {
Warn("slice: omit check for 2nd index")
}
} else {
compare(&j, max)
}
max = &j
}
if i.Op != 0 {
if obvious(&i, max) {
if Debug_slice > 0 {
Warn("slice: omit check for 1st index")
}
} else {
compare(&i, max)
}
max = &i
}
if k.Op != 0 && i.Op != 0 {
obvious(&i, &k) // emit compile-time error for x[3:n:2]
}
if len(panics) > 0 {
p := Gbranch(obj.AJMP, nil, 0)
for _, q := range panics {
Patch(q, Pc)
}
Ginscall(panicslice, -1)
Patch(p, Pc)
}
// Checks are done.
// Compute new len as j-i, cap as k-i.
// If i and j are same register, len is constant 0.
// If i and k are same register, cap is constant 0.
// If j and k are same register, len and cap are same.
// Done with xlen and xcap.
// Now safe to modify j and k even if they alias xlen, xcap.
if xlen.Op == OREGISTER {
Regfree(&xlen)
}
if xcap.Op == OREGISTER {
Regfree(&xcap)
}
// are j and k the same value?
sameJK := same(&j, &k)
if i.Op != 0 {
// j -= i
if same(&i, &j) {
if Debug_slice > 0 {
Warn("slice: result len == 0")
}
if j.Op == OREGISTER {
Regfree(&j)
}
Nodconst(&j, indexRegType, 0)
} else {
switch j.Op {
case OLITERAL:
if Isconst(&i, CTINT) {
Nodconst(&j, indexRegType, j.Int64()-i.Int64())
if Debug_slice > 0 {
Warn("slice: result len == %d", j.Int64())
}
break
}
fallthrough
case ONAME:
if !istemp(&j) {
var r Node
regalloc(&r, indexRegType, nil)
Thearch.Gmove(&j, &r)
j = r
}
fallthrough
case OREGISTER:
if i.Op == OLITERAL {
v := i.Int64()
if v != 0 {
ginscon(Thearch.Optoas(OSUB, indexRegType), v, &j)
}
} else {
gins(Thearch.Optoas(OSUB, indexRegType), &i, &j)
}
}
}
// k -= i if k different from j and cap is needed.j
// (The modifications to j above cannot affect i: if j and i were aliased,
// we replace j with a constant 0 instead of doing a subtraction,
// leaving i unmodified.)
if k.Op == 0 {
if Debug_slice > 0 && n.Op != OSLICESTR {
Warn("slice: result cap not computed")
}
// no need
} else if same(&i, &k) {
if k.Op == OREGISTER {
Regfree(&k)
}
Nodconst(&k, indexRegType, 0)
if Debug_slice > 0 {
Warn("slice: result cap == 0")
}
} else if sameJK {
if Debug_slice > 0 {
Warn("slice: result cap == result len")
}
// k and j were the same value; make k-i the same as j-i.
if k.Op == OREGISTER {
Regfree(&k)
}
k = j
if k.Op == OREGISTER {
Regrealloc(&k)
}
} else {
switch k.Op {
case OLITERAL:
if Isconst(&i, CTINT) {
Nodconst(&k, indexRegType, k.Int64()-i.Int64())
if Debug_slice > 0 {
Warn("slice: result cap == %d", k.Int64())
}
break
}
fallthrough
case ONAME:
if !istemp(&k) {
var r Node
regalloc(&r, indexRegType, nil)
Thearch.Gmove(&k, &r)
k = r
}
fallthrough
case OREGISTER:
if same(&i, &k) {
Regfree(&k)
Nodconst(&k, indexRegType, 0)
if Debug_slice > 0 {
Warn("slice: result cap == 0")
}
} else if i.Op == OLITERAL {
v := i.Int64()
if v != 0 {
ginscon(Thearch.Optoas(OSUB, indexRegType), v, &k)
}
} else {
gins(Thearch.Optoas(OSUB, indexRegType), &i, &k)
}
}
}
}
adjustBase := true
if i.Op == 0 || iszero(&i) {
if Debug_slice > 0 {
Warn("slice: skip base adjustment for 1st index 0")
}
adjustBase = false
} else if k.Op != 0 && iszero(&k) || k.Op == 0 && iszero(&j) {
if Debug_slice > 0 {
if n.Op == OSLICESTR {
Warn("slice: skip base adjustment for string len == 0")
} else {
Warn("slice: skip base adjustment for cap == 0")
}
}
adjustBase = false
}
if !adjustBase && !needFullUpdate {
if Debug_slice > 0 {
if k.Op != 0 {
Warn("slice: len/cap-only update")
} else {
Warn("slice: len-only update")
}
}
if i.Op == OREGISTER {
Regfree(&i)
}
// Write len (and cap if needed) back to x.
x.Xoffset += int64(Widthptr)
x.Type = Types[TUINT]
Thearch.Gmove(&j, &x)
x.Xoffset -= int64(Widthptr)
if k.Op != 0 {
x.Xoffset += 2 * int64(Widthptr)
x.Type = Types[TUINT]
Thearch.Gmove(&k, &x)
x.Xoffset -= 2 * int64(Widthptr)
}
Regfree(&x)
} else {
// Compute new base. May smash i.
if n.Op == OSLICEARR || n.Op == OSLICE3ARR {
Cgenr(n.Left, &xbase, nil)
Cgen_checknil(&xbase)
} else {
var ptr *Type
if n.Op == OSLICESTR {
ptr = ptrToUint8
} else {
ptr = Ptrto(n.Type.Elem())
}
regalloc(&xbase, ptr, nil)
x.Type = xbase.Type
Thearch.Gmove(&x, &xbase)
Regfree(&x)
}
if i.Op != 0 && adjustBase {
// Branch around the base adjustment if the resulting cap will be 0.
var p *obj.Prog
size := &k
if k.Op == 0 {
size = &j
}
if Isconst(size, CTINT) {
// zero was checked above, must be non-zero.
} else {
var tmp Node
Nodconst(&tmp, indexRegType, 0)
p = Thearch.Ginscmp(OEQ, indexRegType, size, &tmp, -1)
}
var w int64
if n.Op == OSLICESTR {
w = 1 // res is string, elem size is 1 (byte)
} else {
w = res.Type.Elem().Width // res is []T, elem size is T.width
}
if Isconst(&i, CTINT) {
ginscon(Thearch.Optoas(OADD, xbase.Type), i.Int64()*w, &xbase)
} else if Thearch.AddIndex != nil && Thearch.AddIndex(&i, w, &xbase) {
// done by back end
} else if w == 1 {
gins(Thearch.Optoas(OADD, xbase.Type), &i, &xbase)
} else {
if i.Op == ONAME && !istemp(&i) {
var tmp Node
Tempname(&tmp, i.Type)
Thearch.Gmove(&i, &tmp)
i = tmp
}
ginscon(Thearch.Optoas(OMUL, i.Type), w, &i)
gins(Thearch.Optoas(OADD, xbase.Type), &i, &xbase)
}
if p != nil {
Patch(p, Pc)
}
}
if i.Op == OREGISTER {
Regfree(&i)
}
// Write len, cap, base to result.
if res.Op == ONAME {
Gvardef(res)
}
Igen(res, &x, nil)
x.Xoffset += int64(Widthptr)
x.Type = Types[TUINT]
Thearch.Gmove(&j, &x)
x.Xoffset -= int64(Widthptr)
if k.Op != 0 {
x.Xoffset += 2 * int64(Widthptr)
Thearch.Gmove(&k, &x)
x.Xoffset -= 2 * int64(Widthptr)
}
x.Type = xbase.Type
cgen_wb(&xbase, &x, wb)
Regfree(&xbase)
Regfree(&x)
}
if j.Op == OREGISTER {
Regfree(&j)
}
if k.Op == OREGISTER {
Regfree(&k)
}
}
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