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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 gc
import (
"cmd/compile/internal/ssa"
"cmd/compile/internal/types"
"cmd/internal/obj"
"cmd/internal/objabi"
"cmd/internal/src"
)
var sharedProgArray = new([10000]obj.Prog) // *T instead of T to work around issue 19839
// 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
curfn *Node // fn these Progs are for
progcache []obj.Prog // local progcache
cacheidx int // first free element of progcache
nextLive LivenessIndex // liveness index for the next Prog
prevLive LivenessIndex // last emitted liveness index
}
// newProgs returns a new Progs for fn.
// worker indicates which of the backend workers will use the Progs.
func newProgs(fn *Node, worker int) *Progs {
pp := new(Progs)
if Ctxt.CanReuseProgs() {
sz := len(sharedProgArray) / nBackendWorkers
pp.progcache = sharedProgArray[sz*worker : sz*(worker+1)]
}
pp.curfn = fn
// prime the pump
pp.next = pp.NewProg()
pp.clearp(pp.next)
pp.pos = fn.Pos
pp.settext(fn)
// PCDATA tables implicitly start with index -1.
pp.prevLive = LivenessIndex{-1, -1, false}
if go115ReduceLiveness {
pp.nextLive = pp.prevLive
} else {
pp.nextLive = LivenessInvalid
}
return pp
}
func (pp *Progs) NewProg() *obj.Prog {
var p *obj.Prog
if pp.cacheidx < len(pp.progcache) {
p = &pp.progcache[pp.cacheidx]
pp.cacheidx++
} else {
p = new(obj.Prog)
}
p.Ctxt = Ctxt
return p
}
// Flush converts from pp to machine code.
func (pp *Progs) Flush() {
plist := &obj.Plist{Firstpc: pp.Text, Curfn: pp.curfn}
obj.Flushplist(Ctxt, plist, pp.NewProg, myimportpath)
}
// Free clears pp and any associated resources.
func (pp *Progs) Free() {
if Ctxt.CanReuseProgs() {
// Clear progs to enable GC and avoid abuse.
s := pp.progcache[:pp.cacheidx]
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.StackMapValid() && pp.nextLive.stackMapIndex != pp.prevLive.stackMapIndex {
// Emit stack map index change.
idx := pp.nextLive.stackMapIndex
pp.prevLive.stackMapIndex = idx
p := pp.Prog(obj.APCDATA)
Addrconst(&p.From, objabi.PCDATA_StackMapIndex)
Addrconst(&p.To, int64(idx))
}
if !go115ReduceLiveness {
if pp.nextLive.isUnsafePoint {
// Unsafe points are encoded as a special value in the
// register map.
pp.nextLive.regMapIndex = objabi.PCDATA_RegMapUnsafe
}
if pp.nextLive.regMapIndex != pp.prevLive.regMapIndex {
// Emit register map index change.
idx := pp.nextLive.regMapIndex
pp.prevLive.regMapIndex = idx
p := pp.Prog(obj.APCDATA)
Addrconst(&p.From, objabi.PCDATA_RegMapIndex)
Addrconst(&p.To, int64(idx))
}
} else {
if pp.nextLive.isUnsafePoint != pp.prevLive.isUnsafePoint {
// Emit unsafe-point marker.
pp.prevLive.isUnsafePoint = pp.nextLive.isUnsafePoint
p := pp.Prog(obj.APCDATA)
Addrconst(&p.From, objabi.PCDATA_UnsafePoint)
if pp.nextLive.isUnsafePoint {
Addrconst(&p.To, objabi.PCDATA_UnsafePointUnsafe)
} else {
Addrconst(&p.To, objabi.PCDATA_UnsafePointSafe)
}
}
}
p := pp.next
pp.next = pp.NewProg()
pp.clearp(pp.next)
p.Link = pp.next
if !pp.pos.IsKnown() && Debug['K'] != 0 {
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 ssa.LosesStmtMark(as) {
return p
}
pp.pos = pp.pos.WithNotStmt()
}
return p
}
func (pp *Progs) clearp(p *obj.Prog) {
obj.Nopout(p)
p.As = obj.AEND
p.Pc = pp.pc
pp.pc++
}
func (pp *Progs) Appendpp(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.clearp(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 *Node) {
if pp.Text != nil {
Fatalf("Progs.settext called twice")
}
ptxt := pp.Prog(obj.ATEXT)
pp.Text = ptxt
fn.Func.lsym.Func.Text = ptxt
ptxt.From.Type = obj.TYPE_MEM
ptxt.From.Name = obj.NAME_EXTERN
ptxt.From.Sym = fn.Func.lsym
}
// initLSym defines f's obj.LSym and initializes it based on the
// properties of f. This includes setting the symbol flags and ABI and
// creating and initializing related DWARF symbols.
//
// initLSym must be called exactly once per function and must be
// called for both functions with bodies and functions without bodies.
func (f *Func) initLSym(hasBody bool) {
if f.lsym != nil {
Fatalf("Func.initLSym called twice")
}
if nam := f.Nname; !nam.isBlank() {
f.lsym = nam.Sym.Linksym()
if f.Pragma&Systemstack != 0 {
f.lsym.Set(obj.AttrCFunc, true)
}
var aliasABI obj.ABI
needABIAlias := false
defABI, hasDefABI := symabiDefs[f.lsym.Name]
if hasDefABI && defABI == obj.ABI0 {
// Symbol is defined as ABI0. Create an
// Internal -> ABI0 wrapper.
f.lsym.SetABI(obj.ABI0)
needABIAlias, aliasABI = true, obj.ABIInternal
} else {
// No ABI override. Check that the symbol is
// using the expected ABI.
want := obj.ABIInternal
if f.lsym.ABI() != want {
Fatalf("function symbol %s has the wrong ABI %v, expected %v", f.lsym.Name, f.lsym.ABI(), want)
}
}
isLinknameExported := nam.Sym.Linkname != "" && (hasBody || hasDefABI)
if abi, ok := symabiRefs[f.lsym.Name]; (ok && abi == obj.ABI0) || isLinknameExported {
// Either 1) this symbol is definitely
// referenced as ABI0 from this package; or 2)
// this symbol is defined in this package but
// given a linkname, indicating that it may be
// referenced from another package. Create an
// ABI0 -> Internal wrapper so it can be
// called as ABI0. In case 2, it's important
// that we know it's defined in this package
// since other packages may "pull" symbols
// using linkname and we don't want to create
// duplicate ABI wrappers.
if f.lsym.ABI() != obj.ABI0 {
needABIAlias, aliasABI = true, obj.ABI0
}
}
if needABIAlias {
// These LSyms have the same name as the
// native function, so we create them directly
// rather than looking them up. The uniqueness
// of f.lsym ensures uniqueness of asym.
asym := &obj.LSym{
Name: f.lsym.Name,
Type: objabi.SABIALIAS,
R: []obj.Reloc{{Sym: f.lsym}}, // 0 size, so "informational"
}
asym.SetABI(aliasABI)
asym.Set(obj.AttrDuplicateOK, true)
Ctxt.ABIAliases = append(Ctxt.ABIAliases, asym)
}
}
if !hasBody {
// For body-less functions, we only create the LSym.
return
}
var flag int
if f.Dupok() {
flag |= obj.DUPOK
}
if f.Wrapper() {
flag |= obj.WRAPPER
}
if f.Needctxt() {
flag |= obj.NEEDCTXT
}
if f.Pragma&Nosplit != 0 {
flag |= obj.NOSPLIT
}
if f.ReflectMethod() {
flag |= obj.REFLECTMETHOD
}
// Clumsy but important.
// See test/recover.go for test cases and src/reflect/value.go
// for the actual functions being considered.
if myimportpath == "reflect" {
switch f.Nname.Sym.Name {
case "callReflect", "callMethod":
flag |= obj.WRAPPER
}
}
Ctxt.InitTextSym(f.lsym, flag)
}
func ggloblnod(nam *Node) {
s := nam.Sym.Linksym()
s.Gotype = ngotype(nam).Linksym()
flags := 0
if nam.Name.Readonly() {
flags = obj.RODATA
}
if nam.Type != nil && !types.Haspointers(nam.Type) {
flags |= obj.NOPTR
}
Ctxt.Globl(s, nam.Type.Width, flags)
if nam.Name.LibfuzzerExtraCounter() {
s.Type = objabi.SLIBFUZZER_EXTRA_COUNTER
}
}
func ggloblsym(s *obj.LSym, width int32, flags int16) {
if flags&obj.LOCAL != 0 {
s.Set(obj.AttrLocal, true)
flags &^= obj.LOCAL
}
Ctxt.Globl(s, int64(width), int(flags))
}
func Addrconst(a *obj.Addr, v int64) {
a.Sym = nil
a.Type = obj.TYPE_CONST
a.Offset = v
}
func Patch(p *obj.Prog, to *obj.Prog) {
if p.To.Type != obj.TYPE_BRANCH {
Fatalf("patch: not a branch")
}
p.To.Val = to
p.To.Offset = to.Pc
}