1 files changed, 333 insertions, 0 deletions
diff --git a/src/cmd/compile/internal/gc/gsubr.go b/src/cmd/compile/internal/gc/gsubr.go
new file mode 100644
index 0000000..d599a38
--- /dev/null
+++ b/src/cmd/compile/internal/gc/gsubr.go
@@ -0,0 +1,333 @@
+// 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/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, false}
+	pp.nextLive = pp.prevLive
+	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 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 && !nam.Type.HasPointers() {
+		flags |= obj.NOPTR
+	}
+	Ctxt.Globl(s, nam.Type.Width, flags)
+	if nam.Name.LibfuzzerExtraCounter() {
+		s.Type = objabi.SLIBFUZZER_EXTRA_COUNTER
+	}
+	if nam.Sym.Linkname != "" {
+		// Make sure linkname'd symbol is non-package. When a symbol is
+		// both imported and linkname'd, s.Pkg may not set to "_" in
+		// types.Sym.Linksym because LSym already exists. Set it here.
+		s.Pkg = "_"
+	}
+}
+
+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.SetTarget(to)
+	p.To.Offset = to.Pc
+}