1 files changed, 352 insertions, 0 deletions
diff --git a/src/cmd/compile/internal/noder/decl.go b/src/cmd/compile/internal/noder/decl.go
new file mode 100644
index 0000000..07353cc
--- /dev/null
+++ b/src/cmd/compile/internal/noder/decl.go
@@ -0,0 +1,352 @@
+// Copyright 2021 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 noder
+
+import (
+	"go/constant"
+
+	"cmd/compile/internal/base"
+	"cmd/compile/internal/ir"
+	"cmd/compile/internal/syntax"
+	"cmd/compile/internal/typecheck"
+	"cmd/compile/internal/types"
+	"cmd/compile/internal/types2"
+)
+
+// TODO(mdempsky): Skip blank declarations? Probably only safe
+// for declarations without pragmas.
+
+func (g *irgen) decls(res *ir.Nodes, decls []syntax.Decl) {
+	for _, decl := range decls {
+		switch decl := decl.(type) {
+		case *syntax.ConstDecl:
+			g.constDecl(res, decl)
+		case *syntax.FuncDecl:
+			g.funcDecl(res, decl)
+		case *syntax.TypeDecl:
+			if ir.CurFunc == nil {
+				continue // already handled in irgen.generate
+			}
+			g.typeDecl(res, decl)
+		case *syntax.VarDecl:
+			g.varDecl(res, decl)
+		default:
+			g.unhandled("declaration", decl)
+		}
+	}
+}
+
+func (g *irgen) importDecl(p *noder, decl *syntax.ImportDecl) {
+	g.pragmaFlags(decl.Pragma, 0)
+
+	// Get the imported package's path, as resolved already by types2
+	// and gcimporter. This is the same path as would be computed by
+	// parseImportPath.
+	switch pkgNameOf(g.info, decl).Imported().Path() {
+	case "unsafe":
+		p.importedUnsafe = true
+	case "embed":
+		p.importedEmbed = true
+	}
+}
+
+// pkgNameOf returns the PkgName associated with the given ImportDecl.
+func pkgNameOf(info *types2.Info, decl *syntax.ImportDecl) *types2.PkgName {
+	if name := decl.LocalPkgName; name != nil {
+		return info.Defs[name].(*types2.PkgName)
+	}
+	return info.Implicits[decl].(*types2.PkgName)
+}
+
+func (g *irgen) constDecl(out *ir.Nodes, decl *syntax.ConstDecl) {
+	g.pragmaFlags(decl.Pragma, 0)
+
+	for _, name := range decl.NameList {
+		name, obj := g.def(name)
+
+		// For untyped numeric constants, make sure the value
+		// representation matches what the rest of the
+		// compiler (really just iexport) expects.
+		// TODO(mdempsky): Revisit after #43891 is resolved.
+		val := obj.(*types2.Const).Val()
+		switch name.Type() {
+		case types.UntypedInt, types.UntypedRune:
+			val = constant.ToInt(val)
+		case types.UntypedFloat:
+			val = constant.ToFloat(val)
+		case types.UntypedComplex:
+			val = constant.ToComplex(val)
+		}
+		name.SetVal(val)
+
+		out.Append(ir.NewDecl(g.pos(decl), ir.ODCLCONST, name))
+	}
+}
+
+func (g *irgen) funcDecl(out *ir.Nodes, decl *syntax.FuncDecl) {
+	assert(g.curDecl == "")
+	// Set g.curDecl to the function name, as context for the type params declared
+	// during types2-to-types1 translation if this is a generic function.
+	g.curDecl = decl.Name.Value
+	obj2 := g.info.Defs[decl.Name]
+	recv := types2.AsSignature(obj2.Type()).Recv()
+	if recv != nil {
+		t2 := deref2(recv.Type())
+		// This is a method, so set g.curDecl to recvTypeName.methName instead.
+		g.curDecl = t2.(*types2.Named).Obj().Name() + "." + g.curDecl
+	}
+
+	fn := ir.NewFunc(g.pos(decl))
+	fn.Nname, _ = g.def(decl.Name)
+	fn.Nname.Func = fn
+	fn.Nname.Defn = fn
+
+	fn.Pragma = g.pragmaFlags(decl.Pragma, funcPragmas)
+	if fn.Pragma&ir.Systemstack != 0 && fn.Pragma&ir.Nosplit != 0 {
+		base.ErrorfAt(fn.Pos(), "go:nosplit and go:systemstack cannot be combined")
+	}
+	if fn.Pragma&ir.Nointerface != 0 {
+		// Propagate //go:nointerface from Func.Pragma to Field.Nointerface.
+		// This is a bit roundabout, but this is the earliest point where we've
+		// processed the function's pragma flags, and we've also already created
+		// the Fields to represent the receiver's method set.
+		if recv := fn.Type().Recv(); recv != nil {
+			typ := types.ReceiverBaseType(recv.Type)
+			if orig := typ.OrigType(); orig != nil {
+				// For a generic method, we mark the methods on the
+				// base generic type, since those are the methods
+				// that will be stenciled.
+				typ = orig
+			}
+			meth := typecheck.Lookdot1(fn, typecheck.Lookup(decl.Name.Value), typ, typ.Methods(), 0)
+			meth.SetNointerface(true)
+		}
+	}
+
+	if decl.Body != nil {
+		if fn.Pragma&ir.Noescape != 0 {
+			base.ErrorfAt(fn.Pos(), "can only use //go:noescape with external func implementations")
+		}
+		if (fn.Pragma&ir.UintptrKeepAlive != 0 && fn.Pragma&ir.UintptrEscapes == 0) && fn.Pragma&ir.Nosplit == 0 {
+			// Stack growth can't handle uintptr arguments that may
+			// be pointers (as we don't know which are pointers
+			// when creating the stack map). Thus uintptrkeepalive
+			// functions (and all transitive callees) must be
+			// nosplit.
+			//
+			// N.B. uintptrescapes implies uintptrkeepalive but it
+			// is OK since the arguments must escape to the heap.
+			//
+			// TODO(prattmic): Add recursive nosplit check of callees.
+			// TODO(prattmic): Functions with no body (i.e.,
+			// assembly) must also be nosplit, but we can't check
+			// that here.
+			base.ErrorfAt(fn.Pos(), "go:uintptrkeepalive requires go:nosplit")
+		}
+	}
+
+	if decl.Name.Value == "init" && decl.Recv == nil {
+		g.target.Inits = append(g.target.Inits, fn)
+	}
+
+	saveHaveEmbed := g.haveEmbed
+	saveCurDecl := g.curDecl
+	g.curDecl = ""
+	g.later(func() {
+		defer func(b bool, s string) {
+			// Revert haveEmbed and curDecl back to what they were before
+			// the "later" function.
+			g.haveEmbed = b
+			g.curDecl = s
+		}(g.haveEmbed, g.curDecl)
+
+		// Set haveEmbed and curDecl to what they were for this funcDecl.
+		g.haveEmbed = saveHaveEmbed
+		g.curDecl = saveCurDecl
+		if fn.Type().HasTParam() {
+			g.topFuncIsGeneric = true
+		}
+		g.funcBody(fn, decl.Recv, decl.Type, decl.Body)
+		g.topFuncIsGeneric = false
+		if fn.Type().HasTParam() && fn.Body != nil {
+			// Set pointers to the dcls/body of a generic function/method in
+			// the Inl struct, so it is marked for export, is available for
+			// stenciling, and works with Inline_Flood().
+			fn.Inl = &ir.Inline{
+				Cost: 1,
+				Dcl:  fn.Dcl,
+				Body: fn.Body,
+			}
+		}
+
+		out.Append(fn)
+	})
+}
+
+func (g *irgen) typeDecl(out *ir.Nodes, decl *syntax.TypeDecl) {
+	// Set the position for any error messages we might print (e.g. too large types).
+	base.Pos = g.pos(decl)
+	assert(ir.CurFunc != nil || g.curDecl == "")
+	// Set g.curDecl to the type name, as context for the type params declared
+	// during types2-to-types1 translation if this is a generic type.
+	saveCurDecl := g.curDecl
+	g.curDecl = decl.Name.Value
+	if decl.Alias {
+		name, _ := g.def(decl.Name)
+		g.pragmaFlags(decl.Pragma, 0)
+		assert(name.Alias()) // should be set by irgen.obj
+
+		out.Append(ir.NewDecl(g.pos(decl), ir.ODCLTYPE, name))
+		g.curDecl = ""
+		return
+	}
+
+	// Prevent size calculations until we set the underlying type.
+	types.DeferCheckSize()
+
+	name, obj := g.def(decl.Name)
+	ntyp, otyp := name.Type(), obj.Type()
+	if ir.CurFunc != nil {
+		ntyp.SetVargen()
+	}
+
+	pragmas := g.pragmaFlags(decl.Pragma, 0)
+	name.SetPragma(pragmas) // TODO(mdempsky): Is this still needed?
+
+	ntyp.SetUnderlying(g.typeExpr(decl.Type))
+
+	tparams := otyp.(*types2.Named).TypeParams()
+	if n := tparams.Len(); n > 0 {
+		rparams := make([]*types.Type, n)
+		for i := range rparams {
+			rparams[i] = g.typ(tparams.At(i))
+		}
+		// This will set hasTParam flag if any rparams are not concrete types.
+		ntyp.SetRParams(rparams)
+	}
+	types.ResumeCheckSize()
+
+	g.curDecl = saveCurDecl
+	if otyp, ok := otyp.(*types2.Named); ok && otyp.NumMethods() != 0 {
+		methods := make([]*types.Field, otyp.NumMethods())
+		for i := range methods {
+			m := otyp.Method(i)
+			// Set g.curDecl to recvTypeName.methName, as context for the
+			// method-specific type params in the receiver.
+			g.curDecl = decl.Name.Value + "." + m.Name()
+			meth := g.obj(m)
+			methods[i] = types.NewField(meth.Pos(), g.selector(m), meth.Type())
+			methods[i].Nname = meth
+			g.curDecl = ""
+		}
+		ntyp.Methods().Set(methods)
+	}
+
+	out.Append(ir.NewDecl(g.pos(decl), ir.ODCLTYPE, name))
+}
+
+func (g *irgen) varDecl(out *ir.Nodes, decl *syntax.VarDecl) {
+	pos := g.pos(decl)
+	// Set the position for any error messages we might print (e.g. too large types).
+	base.Pos = pos
+	names := make([]*ir.Name, len(decl.NameList))
+	for i, name := range decl.NameList {
+		names[i], _ = g.def(name)
+	}
+
+	if decl.Pragma != nil {
+		pragma := decl.Pragma.(*pragmas)
+		varEmbed(g.makeXPos, names[0], decl, pragma, g.haveEmbed)
+		g.reportUnused(pragma)
+	}
+
+	haveEmbed := g.haveEmbed
+	do := func() {
+		defer func(b bool) { g.haveEmbed = b }(g.haveEmbed)
+
+		g.haveEmbed = haveEmbed
+		values := g.exprList(decl.Values)
+
+		var as2 *ir.AssignListStmt
+		if len(values) != 0 && len(names) != len(values) {
+			as2 = ir.NewAssignListStmt(pos, ir.OAS2, make([]ir.Node, len(names)), values)
+		}
+
+		for i, name := range names {
+			if ir.CurFunc != nil {
+				out.Append(ir.NewDecl(pos, ir.ODCL, name))
+			}
+			if as2 != nil {
+				as2.Lhs[i] = name
+				name.Defn = as2
+			} else {
+				as := ir.NewAssignStmt(pos, name, nil)
+				if len(values) != 0 {
+					as.Y = values[i]
+					name.Defn = as
+				} else if ir.CurFunc == nil {
+					name.Defn = as
+				}
+				if !g.delayTransform() {
+					lhs := []ir.Node{as.X}
+					rhs := []ir.Node{}
+					if as.Y != nil {
+						rhs = []ir.Node{as.Y}
+					}
+					transformAssign(as, lhs, rhs)
+					as.X = lhs[0]
+					if as.Y != nil {
+						as.Y = rhs[0]
+					}
+				}
+				as.SetTypecheck(1)
+				out.Append(as)
+			}
+		}
+		if as2 != nil {
+			if !g.delayTransform() {
+				transformAssign(as2, as2.Lhs, as2.Rhs)
+			}
+			as2.SetTypecheck(1)
+			out.Append(as2)
+		}
+	}
+
+	// If we're within a function, we need to process the assignment
+	// part of the variable declaration right away. Otherwise, we leave
+	// it to be handled after all top-level declarations are processed.
+	if ir.CurFunc != nil {
+		do()
+	} else {
+		g.later(do)
+	}
+}
+
+// pragmaFlags returns any specified pragma flags included in allowed,
+// and reports errors about any other, unexpected pragmas.
+func (g *irgen) pragmaFlags(pragma syntax.Pragma, allowed ir.PragmaFlag) ir.PragmaFlag {
+	if pragma == nil {
+		return 0
+	}
+	p := pragma.(*pragmas)
+	present := p.Flag & allowed
+	p.Flag &^= allowed
+	g.reportUnused(p)
+	return present
+}
+
+// reportUnused reports errors about any unused pragmas.
+func (g *irgen) reportUnused(pragma *pragmas) {
+	for _, pos := range pragma.Pos {
+		if pos.Flag&pragma.Flag != 0 {
+			base.ErrorfAt(g.makeXPos(pos.Pos), "misplaced compiler directive")
+		}
+	}
+	if len(pragma.Embeds) > 0 {
+		for _, e := range pragma.Embeds {
+			base.ErrorfAt(g.makeXPos(e.Pos), "misplaced go:embed directive")
+		}
+	}
+}