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// Derived from Inferno utils/6c/txt.c
// https://bitbucket.org/inferno-os/inferno-os/src/master/utils/6c/txt.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 objw
import (
"cmd/compile/internal/base"
"cmd/compile/internal/ir"
"cmd/internal/obj"
"cmd/internal/src"
"internal/abi"
)
var sharedProgArray = new([10000]obj.Prog) // *T instead of T to work around issue 19839
// NewProgs returns a new Progs for fn.
// worker indicates which of the backend workers will use the Progs.
func NewProgs(fn *ir.Func, worker int) *Progs {
pp := new(Progs)
if base.Ctxt.CanReuseProgs() {
sz := len(sharedProgArray) / base.Flag.LowerC
pp.Cache = sharedProgArray[sz*worker : sz*(worker+1)]
}
pp.CurFunc = fn
// prime the pump
pp.Next = pp.NewProg()
pp.Clear(pp.Next)
pp.Pos = fn.Pos()
pp.SetText(fn)
// PCDATA tables implicitly start with index -1.
pp.PrevLive = -1
pp.NextLive = pp.PrevLive
pp.NextUnsafe = pp.PrevUnsafe
return pp
}
// Progs accumulates Progs for a function and converts them into machine code.
type Progs struct {
Text *obj.Prog // ATEXT Prog for this function
Next *obj.Prog // next Prog
PC int64 // virtual PC; count of Progs
Pos src.XPos // position to use for new Progs
CurFunc *ir.Func // fn these Progs are for
Cache []obj.Prog // local progcache
CacheIndex int // first free element of progcache
NextLive StackMapIndex // liveness index for the next Prog
PrevLive StackMapIndex // last emitted liveness index
NextUnsafe bool // unsafe mark for the next Prog
PrevUnsafe bool // last emitted unsafe mark
}
type StackMapIndex int
// StackMapDontCare indicates that the stack map index at a Value
// doesn't matter.
//
// This is a sentinel value that should never be emitted to the PCDATA
// stream. We use -1000 because that's obviously never a valid stack
// index (but -1 is).
const StackMapDontCare StackMapIndex = -1000
func (s StackMapIndex) StackMapValid() bool {
return s != StackMapDontCare
}
func (pp *Progs) NewProg() *obj.Prog {
var p *obj.Prog
if pp.CacheIndex < len(pp.Cache) {
p = &pp.Cache[pp.CacheIndex]
pp.CacheIndex++
} else {
p = new(obj.Prog)
}
p.Ctxt = base.Ctxt
return p
}
// Flush converts from pp to machine code.
func (pp *Progs) Flush() {
plist := &obj.Plist{Firstpc: pp.Text, Curfn: pp.CurFunc}
obj.Flushplist(base.Ctxt, plist, pp.NewProg)
}
// Free clears pp and any associated resources.
func (pp *Progs) Free() {
if base.Ctxt.CanReuseProgs() {
// Clear progs to enable GC and avoid abuse.
s := pp.Cache[:pp.CacheIndex]
for i := range s {
s[i] = obj.Prog{}
}
}
// Clear pp to avoid abuse.
*pp = Progs{}
}
// Prog adds a Prog with instruction As to pp.
func (pp *Progs) Prog(as obj.As) *obj.Prog {
if pp.NextLive != StackMapDontCare && pp.NextLive != pp.PrevLive {
// Emit stack map index change.
idx := pp.NextLive
pp.PrevLive = idx
p := pp.Prog(obj.APCDATA)
p.From.SetConst(abi.PCDATA_StackMapIndex)
p.To.SetConst(int64(idx))
}
if pp.NextUnsafe != pp.PrevUnsafe {
// Emit unsafe-point marker.
pp.PrevUnsafe = pp.NextUnsafe
p := pp.Prog(obj.APCDATA)
p.From.SetConst(abi.PCDATA_UnsafePoint)
if pp.NextUnsafe {
p.To.SetConst(abi.UnsafePointUnsafe)
} else {
p.To.SetConst(abi.UnsafePointSafe)
}
}
p := pp.Next
pp.Next = pp.NewProg()
pp.Clear(pp.Next)
p.Link = pp.Next
if !pp.Pos.IsKnown() && base.Flag.K != 0 {
base.Warn("prog: unknown position (line 0)")
}
p.As = as
p.Pos = pp.Pos
if pp.Pos.IsStmt() == src.PosIsStmt {
// Clear IsStmt for later Progs at this pos provided that as can be marked as a stmt
if LosesStmtMark(as) {
return p
}
pp.Pos = pp.Pos.WithNotStmt()
}
return p
}
func (pp *Progs) Clear(p *obj.Prog) {
obj.Nopout(p)
p.As = obj.AEND
p.Pc = pp.PC
pp.PC++
}
func (pp *Progs) Append(p *obj.Prog, as obj.As, ftype obj.AddrType, freg int16, foffset int64, ttype obj.AddrType, treg int16, toffset int64) *obj.Prog {
q := pp.NewProg()
pp.Clear(q)
q.As = as
q.Pos = p.Pos
q.From.Type = ftype
q.From.Reg = freg
q.From.Offset = foffset
q.To.Type = ttype
q.To.Reg = treg
q.To.Offset = toffset
q.Link = p.Link
p.Link = q
return q
}
func (pp *Progs) SetText(fn *ir.Func) {
if pp.Text != nil {
base.Fatalf("Progs.SetText called twice")
}
ptxt := pp.Prog(obj.ATEXT)
pp.Text = ptxt
fn.LSym.Func().Text = ptxt
ptxt.From.Type = obj.TYPE_MEM
ptxt.From.Name = obj.NAME_EXTERN
ptxt.From.Sym = fn.LSym
}
// LosesStmtMark reports whether a prog with op as loses its statement mark on the way to DWARF.
// The attributes from some opcodes are lost in translation.
// TODO: this is an artifact of how funcpctab combines information for instructions at a single PC.
// Should try to fix it there.
func LosesStmtMark(as obj.As) bool {
// is_stmt does not work for these; it DOES for ANOP even though that generates no code.
return as == obj.APCDATA || as == obj.AFUNCDATA
}
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