Adding upstream version 1.18.10.upstream/1.18.10upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 609 insertions, 0 deletions

diff --git a/src/cmd/compile/internal/staticinit/sched.go b/src/cmd/compile/internal/staticinit/sched.go
new file mode 100644
index 0000000..636199d
--- /dev/null
+++ b/src/cmd/compile/internal/staticinit/sched.go
@@ -0,0 +1,609 @@
+// 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 staticinit
+
+import (
+	"fmt"
+	"go/constant"
+
+	"cmd/compile/internal/base"
+	"cmd/compile/internal/ir"
+	"cmd/compile/internal/reflectdata"
+	"cmd/compile/internal/staticdata"
+	"cmd/compile/internal/typecheck"
+	"cmd/compile/internal/types"
+	"cmd/internal/obj"
+	"cmd/internal/src"
+)
+
+type Entry struct {
+	Xoffset int64   // struct, array only
+	Expr    ir.Node // bytes of run-time computed expressions
+}
+
+type Plan struct {
+	E []Entry
+}
+
+// An Schedule is used to decompose assignment statements into
+// static and dynamic initialization parts. Static initializations are
+// handled by populating variables' linker symbol data, while dynamic
+// initializations are accumulated to be executed in order.
+type Schedule struct {
+	// Out is the ordered list of dynamic initialization
+	// statements.
+	Out []ir.Node
+
+	Plans map[ir.Node]*Plan
+	Temps map[ir.Node]*ir.Name
+}
+
+func (s *Schedule) append(n ir.Node) {
+	s.Out = append(s.Out, n)
+}
+
+// StaticInit adds an initialization statement n to the schedule.
+func (s *Schedule) StaticInit(n ir.Node) {
+	if !s.tryStaticInit(n) {
+		if base.Flag.Percent != 0 {
+			ir.Dump("nonstatic", n)
+		}
+		s.append(n)
+	}
+}
+
+// tryStaticInit attempts to statically execute an initialization
+// statement and reports whether it succeeded.
+func (s *Schedule) tryStaticInit(nn ir.Node) bool {
+	// Only worry about simple "l = r" assignments. Multiple
+	// variable/expression OAS2 assignments have already been
+	// replaced by multiple simple OAS assignments, and the other
+	// OAS2* assignments mostly necessitate dynamic execution
+	// anyway.
+	if nn.Op() != ir.OAS {
+		return false
+	}
+	n := nn.(*ir.AssignStmt)
+	if ir.IsBlank(n.X) && !AnySideEffects(n.Y) {
+		// Discard.
+		return true
+	}
+	lno := ir.SetPos(n)
+	defer func() { base.Pos = lno }()
+	nam := n.X.(*ir.Name)
+	return s.StaticAssign(nam, 0, n.Y, nam.Type())
+}
+
+// like staticassign but we are copying an already
+// initialized value r.
+func (s *Schedule) staticcopy(l *ir.Name, loff int64, rn *ir.Name, typ *types.Type) bool {
+	if rn.Class == ir.PFUNC {
+		// TODO if roff != 0 { panic }
+		staticdata.InitAddr(l, loff, staticdata.FuncLinksym(rn))
+		return true
+	}
+	if rn.Class != ir.PEXTERN || rn.Sym().Pkg != types.LocalPkg {
+		return false
+	}
+	if rn.Defn.Op() != ir.OAS {
+		return false
+	}
+	if rn.Type().IsString() { // perhaps overwritten by cmd/link -X (#34675)
+		return false
+	}
+	if rn.Embed != nil {
+		return false
+	}
+	orig := rn
+	r := rn.Defn.(*ir.AssignStmt).Y
+	if r == nil {
+		// No explicit initialization value. Probably zeroed but perhaps
+		// supplied externally and of unknown value.
+		return false
+	}
+
+	for r.Op() == ir.OCONVNOP && !types.Identical(r.Type(), typ) {
+		r = r.(*ir.ConvExpr).X
+	}
+
+	switch r.Op() {
+	case ir.OMETHEXPR:
+		r = r.(*ir.SelectorExpr).FuncName()
+		fallthrough
+	case ir.ONAME:
+		r := r.(*ir.Name)
+		if s.staticcopy(l, loff, r, typ) {
+			return true
+		}
+		// We may have skipped past one or more OCONVNOPs, so
+		// use conv to ensure r is assignable to l (#13263).
+		dst := ir.Node(l)
+		if loff != 0 || !types.Identical(typ, l.Type()) {
+			dst = ir.NewNameOffsetExpr(base.Pos, l, loff, typ)
+		}
+		s.append(ir.NewAssignStmt(base.Pos, dst, typecheck.Conv(r, typ)))
+		return true
+
+	case ir.ONIL:
+		return true
+
+	case ir.OLITERAL:
+		if ir.IsZero(r) {
+			return true
+		}
+		staticdata.InitConst(l, loff, r, int(typ.Size()))
+		return true
+
+	case ir.OADDR:
+		r := r.(*ir.AddrExpr)
+		if a, ok := r.X.(*ir.Name); ok && a.Op() == ir.ONAME {
+			staticdata.InitAddr(l, loff, staticdata.GlobalLinksym(a))
+			return true
+		}
+
+	case ir.OPTRLIT:
+		r := r.(*ir.AddrExpr)
+		switch r.X.Op() {
+		case ir.OARRAYLIT, ir.OSLICELIT, ir.OSTRUCTLIT, ir.OMAPLIT:
+			// copy pointer
+			staticdata.InitAddr(l, loff, staticdata.GlobalLinksym(s.Temps[r]))
+			return true
+		}
+
+	case ir.OSLICELIT:
+		r := r.(*ir.CompLitExpr)
+		// copy slice
+		staticdata.InitSlice(l, loff, staticdata.GlobalLinksym(s.Temps[r]), r.Len)
+		return true
+
+	case ir.OARRAYLIT, ir.OSTRUCTLIT:
+		r := r.(*ir.CompLitExpr)
+		p := s.Plans[r]
+		for i := range p.E {
+			e := &p.E[i]
+			typ := e.Expr.Type()
+			if e.Expr.Op() == ir.OLITERAL || e.Expr.Op() == ir.ONIL {
+				staticdata.InitConst(l, loff+e.Xoffset, e.Expr, int(typ.Size()))
+				continue
+			}
+			x := e.Expr
+			if x.Op() == ir.OMETHEXPR {
+				x = x.(*ir.SelectorExpr).FuncName()
+			}
+			if x.Op() == ir.ONAME && s.staticcopy(l, loff+e.Xoffset, x.(*ir.Name), typ) {
+				continue
+			}
+			// Requires computation, but we're
+			// copying someone else's computation.
+			ll := ir.NewNameOffsetExpr(base.Pos, l, loff+e.Xoffset, typ)
+			rr := ir.NewNameOffsetExpr(base.Pos, orig, e.Xoffset, typ)
+			ir.SetPos(rr)
+			s.append(ir.NewAssignStmt(base.Pos, ll, rr))
+		}
+
+		return true
+	}
+
+	return false
+}
+
+func (s *Schedule) StaticAssign(l *ir.Name, loff int64, r ir.Node, typ *types.Type) bool {
+	if r == nil {
+		// No explicit initialization value. Either zero or supplied
+		// externally.
+		return true
+	}
+	for r.Op() == ir.OCONVNOP {
+		r = r.(*ir.ConvExpr).X
+	}
+
+	assign := func(pos src.XPos, a *ir.Name, aoff int64, v ir.Node) {
+		if s.StaticAssign(a, aoff, v, v.Type()) {
+			return
+		}
+		var lhs ir.Node
+		if ir.IsBlank(a) {
+			// Don't use NameOffsetExpr with blank (#43677).
+			lhs = ir.BlankNode
+		} else {
+			lhs = ir.NewNameOffsetExpr(pos, a, aoff, v.Type())
+		}
+		s.append(ir.NewAssignStmt(pos, lhs, v))
+	}
+
+	switch r.Op() {
+	case ir.ONAME:
+		r := r.(*ir.Name)
+		return s.staticcopy(l, loff, r, typ)
+
+	case ir.OMETHEXPR:
+		r := r.(*ir.SelectorExpr)
+		return s.staticcopy(l, loff, r.FuncName(), typ)
+
+	case ir.ONIL:
+		return true
+
+	case ir.OLITERAL:
+		if ir.IsZero(r) {
+			return true
+		}
+		staticdata.InitConst(l, loff, r, int(typ.Size()))
+		return true
+
+	case ir.OADDR:
+		r := r.(*ir.AddrExpr)
+		if name, offset, ok := StaticLoc(r.X); ok && name.Class == ir.PEXTERN {
+			staticdata.InitAddrOffset(l, loff, name.Linksym(), offset)
+			return true
+		}
+		fallthrough
+
+	case ir.OPTRLIT:
+		r := r.(*ir.AddrExpr)
+		switch r.X.Op() {
+		case ir.OARRAYLIT, ir.OSLICELIT, ir.OMAPLIT, ir.OSTRUCTLIT:
+			// Init pointer.
+			a := StaticName(r.X.Type())
+
+			s.Temps[r] = a
+			staticdata.InitAddr(l, loff, a.Linksym())
+
+			// Init underlying literal.
+			assign(base.Pos, a, 0, r.X)
+			return true
+		}
+		//dump("not static ptrlit", r);
+
+	case ir.OSTR2BYTES:
+		r := r.(*ir.ConvExpr)
+		if l.Class == ir.PEXTERN && r.X.Op() == ir.OLITERAL {
+			sval := ir.StringVal(r.X)
+			staticdata.InitSliceBytes(l, loff, sval)
+			return true
+		}
+
+	case ir.OSLICELIT:
+		r := r.(*ir.CompLitExpr)
+		s.initplan(r)
+		// Init slice.
+		ta := types.NewArray(r.Type().Elem(), r.Len)
+		ta.SetNoalg(true)
+		a := StaticName(ta)
+		s.Temps[r] = a
+		staticdata.InitSlice(l, loff, a.Linksym(), r.Len)
+		// Fall through to init underlying array.
+		l = a
+		loff = 0
+		fallthrough
+
+	case ir.OARRAYLIT, ir.OSTRUCTLIT:
+		r := r.(*ir.CompLitExpr)
+		s.initplan(r)
+
+		p := s.Plans[r]
+		for i := range p.E {
+			e := &p.E[i]
+			if e.Expr.Op() == ir.OLITERAL || e.Expr.Op() == ir.ONIL {
+				staticdata.InitConst(l, loff+e.Xoffset, e.Expr, int(e.Expr.Type().Size()))
+				continue
+			}
+			ir.SetPos(e.Expr)
+			assign(base.Pos, l, loff+e.Xoffset, e.Expr)
+		}
+
+		return true
+
+	case ir.OMAPLIT:
+		break
+
+	case ir.OCLOSURE:
+		r := r.(*ir.ClosureExpr)
+		if ir.IsTrivialClosure(r) {
+			if base.Debug.Closure > 0 {
+				base.WarnfAt(r.Pos(), "closure converted to global")
+			}
+			// Closures with no captured variables are globals,
+			// so the assignment can be done at link time.
+			// TODO if roff != 0 { panic }
+			staticdata.InitAddr(l, loff, staticdata.FuncLinksym(r.Func.Nname))
+			return true
+		}
+		ir.ClosureDebugRuntimeCheck(r)
+
+	case ir.OCONVIFACE:
+		// This logic is mirrored in isStaticCompositeLiteral.
+		// If you change something here, change it there, and vice versa.
+
+		// Determine the underlying concrete type and value we are converting from.
+		r := r.(*ir.ConvExpr)
+		val := ir.Node(r)
+		for val.Op() == ir.OCONVIFACE {
+			val = val.(*ir.ConvExpr).X
+		}
+
+		if val.Type().IsInterface() {
+			// val is an interface type.
+			// If val is nil, we can statically initialize l;
+			// both words are zero and so there no work to do, so report success.
+			// If val is non-nil, we have no concrete type to record,
+			// and we won't be able to statically initialize its value, so report failure.
+			return val.Op() == ir.ONIL
+		}
+
+		reflectdata.MarkTypeUsedInInterface(val.Type(), l.Linksym())
+
+		var itab *ir.AddrExpr
+		if typ.IsEmptyInterface() {
+			itab = reflectdata.TypePtr(val.Type())
+		} else {
+			itab = reflectdata.ITabAddr(val.Type(), typ)
+		}
+
+		// Create a copy of l to modify while we emit data.
+
+		// Emit itab, advance offset.
+		staticdata.InitAddr(l, loff, itab.X.(*ir.LinksymOffsetExpr).Linksym)
+
+		// Emit data.
+		if types.IsDirectIface(val.Type()) {
+			if val.Op() == ir.ONIL {
+				// Nil is zero, nothing to do.
+				return true
+			}
+			// Copy val directly into n.
+			ir.SetPos(val)
+			assign(base.Pos, l, loff+int64(types.PtrSize), val)
+		} else {
+			// Construct temp to hold val, write pointer to temp into n.
+			a := StaticName(val.Type())
+			s.Temps[val] = a
+			assign(base.Pos, a, 0, val)
+			staticdata.InitAddr(l, loff+int64(types.PtrSize), a.Linksym())
+		}
+
+		return true
+	}
+
+	//dump("not static", r);
+	return false
+}
+
+func (s *Schedule) initplan(n ir.Node) {
+	if s.Plans[n] != nil {
+		return
+	}
+	p := new(Plan)
+	s.Plans[n] = p
+	switch n.Op() {
+	default:
+		base.Fatalf("initplan")
+
+	case ir.OARRAYLIT, ir.OSLICELIT:
+		n := n.(*ir.CompLitExpr)
+		var k int64
+		for _, a := range n.List {
+			if a.Op() == ir.OKEY {
+				kv := a.(*ir.KeyExpr)
+				k = typecheck.IndexConst(kv.Key)
+				if k < 0 {
+					base.Fatalf("initplan arraylit: invalid index %v", kv.Key)
+				}
+				a = kv.Value
+			}
+			s.addvalue(p, k*n.Type().Elem().Size(), a)
+			k++
+		}
+
+	case ir.OSTRUCTLIT:
+		n := n.(*ir.CompLitExpr)
+		for _, a := range n.List {
+			if a.Op() != ir.OSTRUCTKEY {
+				base.Fatalf("initplan structlit")
+			}
+			a := a.(*ir.StructKeyExpr)
+			if a.Sym().IsBlank() {
+				continue
+			}
+			s.addvalue(p, a.Field.Offset, a.Value)
+		}
+
+	case ir.OMAPLIT:
+		n := n.(*ir.CompLitExpr)
+		for _, a := range n.List {
+			if a.Op() != ir.OKEY {
+				base.Fatalf("initplan maplit")
+			}
+			a := a.(*ir.KeyExpr)
+			s.addvalue(p, -1, a.Value)
+		}
+	}
+}
+
+func (s *Schedule) addvalue(p *Plan, xoffset int64, n ir.Node) {
+	// special case: zero can be dropped entirely
+	if ir.IsZero(n) {
+		return
+	}
+
+	// special case: inline struct and array (not slice) literals
+	if isvaluelit(n) {
+		s.initplan(n)
+		q := s.Plans[n]
+		for _, qe := range q.E {
+			// qe is a copy; we are not modifying entries in q.E
+			qe.Xoffset += xoffset
+			p.E = append(p.E, qe)
+		}
+		return
+	}
+
+	// add to plan
+	p.E = append(p.E, Entry{Xoffset: xoffset, Expr: n})
+}
+
+// from here down is the walk analysis
+// of composite literals.
+// most of the work is to generate
+// data statements for the constant
+// part of the composite literal.
+
+var statuniqgen int // name generator for static temps
+
+// StaticName returns a name backed by a (writable) static data symbol.
+// Use readonlystaticname for read-only node.
+func StaticName(t *types.Type) *ir.Name {
+	// Don't use LookupNum; it interns the resulting string, but these are all unique.
+	n := typecheck.NewName(typecheck.Lookup(fmt.Sprintf("%s%d", obj.StaticNamePref, statuniqgen)))
+	statuniqgen++
+	typecheck.Declare(n, ir.PEXTERN)
+	n.SetType(t)
+	return n
+}
+
+// StaticLoc returns the static address of n, if n has one, or else nil.
+func StaticLoc(n ir.Node) (name *ir.Name, offset int64, ok bool) {
+	if n == nil {
+		return nil, 0, false
+	}
+
+	switch n.Op() {
+	case ir.ONAME:
+		n := n.(*ir.Name)
+		return n, 0, true
+
+	case ir.OMETHEXPR:
+		n := n.(*ir.SelectorExpr)
+		return StaticLoc(n.FuncName())
+
+	case ir.ODOT:
+		n := n.(*ir.SelectorExpr)
+		if name, offset, ok = StaticLoc(n.X); !ok {
+			break
+		}
+		offset += n.Offset()
+		return name, offset, true
+
+	case ir.OINDEX:
+		n := n.(*ir.IndexExpr)
+		if n.X.Type().IsSlice() {
+			break
+		}
+		if name, offset, ok = StaticLoc(n.X); !ok {
+			break
+		}
+		l := getlit(n.Index)
+		if l < 0 {
+			break
+		}
+
+		// Check for overflow.
+		if n.Type().Size() != 0 && types.MaxWidth/n.Type().Size() <= int64(l) {
+			break
+		}
+		offset += int64(l) * n.Type().Size()
+		return name, offset, true
+	}
+
+	return nil, 0, false
+}
+
+// AnySideEffects reports whether n contains any operations that could have observable side effects.
+func AnySideEffects(n ir.Node) bool {
+	return ir.Any(n, func(n ir.Node) bool {
+		switch n.Op() {
+		// Assume side effects unless we know otherwise.
+		default:
+			return true
+
+		// No side effects here (arguments are checked separately).
+		case ir.ONAME,
+			ir.ONONAME,
+			ir.OTYPE,
+			ir.OPACK,
+			ir.OLITERAL,
+			ir.ONIL,
+			ir.OADD,
+			ir.OSUB,
+			ir.OOR,
+			ir.OXOR,
+			ir.OADDSTR,
+			ir.OADDR,
+			ir.OANDAND,
+			ir.OBYTES2STR,
+			ir.ORUNES2STR,
+			ir.OSTR2BYTES,
+			ir.OSTR2RUNES,
+			ir.OCAP,
+			ir.OCOMPLIT,
+			ir.OMAPLIT,
+			ir.OSTRUCTLIT,
+			ir.OARRAYLIT,
+			ir.OSLICELIT,
+			ir.OPTRLIT,
+			ir.OCONV,
+			ir.OCONVIFACE,
+			ir.OCONVNOP,
+			ir.ODOT,
+			ir.OEQ,
+			ir.ONE,
+			ir.OLT,
+			ir.OLE,
+			ir.OGT,
+			ir.OGE,
+			ir.OKEY,
+			ir.OSTRUCTKEY,
+			ir.OLEN,
+			ir.OMUL,
+			ir.OLSH,
+			ir.ORSH,
+			ir.OAND,
+			ir.OANDNOT,
+			ir.ONEW,
+			ir.ONOT,
+			ir.OBITNOT,
+			ir.OPLUS,
+			ir.ONEG,
+			ir.OOROR,
+			ir.OPAREN,
+			ir.ORUNESTR,
+			ir.OREAL,
+			ir.OIMAG,
+			ir.OCOMPLEX:
+			return false
+
+		// Only possible side effect is division by zero.
+		case ir.ODIV, ir.OMOD:
+			n := n.(*ir.BinaryExpr)
+			if n.Y.Op() != ir.OLITERAL || constant.Sign(n.Y.Val()) == 0 {
+				return true
+			}
+
+		// Only possible side effect is panic on invalid size,
+		// but many makechan and makemap use size zero, which is definitely OK.
+		case ir.OMAKECHAN, ir.OMAKEMAP:
+			n := n.(*ir.MakeExpr)
+			if !ir.IsConst(n.Len, constant.Int) || constant.Sign(n.Len.Val()) != 0 {
+				return true
+			}
+
+		// Only possible side effect is panic on invalid size.
+		// TODO(rsc): Merge with previous case (probably breaks toolstash -cmp).
+		case ir.OMAKESLICE, ir.OMAKESLICECOPY:
+			return true
+		}
+		return false
+	})
+}
+
+func getlit(lit ir.Node) int {
+	if ir.IsSmallIntConst(lit) {
+		return int(ir.Int64Val(lit))
+	}
+	return -1
+}
+
+func isvaluelit(n ir.Node) bool {
+	return n.Op() == ir.OARRAYLIT || n.Op() == ir.OSTRUCTLIT
+}