1 files changed, 100 insertions, 0 deletions
diff --git a/src/cmd/compile/internal/ir/func.go b/src/cmd/compile/internal/ir/func.go
index 1d76813a4c..3d4f8c4486 100644
--- a/src/cmd/compile/internal/ir/func.go
+++ b/src/cmd/compile/internal/ir/func.go
@@ -9,6 +9,7 @@ import (
 	"cmd/compile/internal/types"
 	"cmd/internal/obj"
 	"cmd/internal/src"
+	"fmt"
 )
 
 // A Func corresponds to a single function in a Go program
@@ -311,3 +312,102 @@ func ClosureDebugRuntimeCheck(clo *ClosureExpr) {
 func IsTrivialClosure(clo *ClosureExpr) bool {
 	return len(clo.Func.ClosureVars) == 0
 }
+
+// globClosgen is like Func.Closgen, but for the global scope.
+var globClosgen int32
+
+// closureName generates a new unique name for a closure within outerfn.
+func closureName(outerfn *Func) *types.Sym {
+	pkg := types.LocalPkg
+	outer := "glob."
+	prefix := "func"
+	gen := &globClosgen
+
+	if outerfn != nil {
+		if outerfn.OClosure != nil {
+			prefix = ""
+		}
+
+		pkg = outerfn.Sym().Pkg
+		outer = FuncName(outerfn)
+
+		// There may be multiple functions named "_". In those
+		// cases, we can't use their individual Closgens as it
+		// would lead to name clashes.
+		if !IsBlank(outerfn.Nname) {
+			gen = &outerfn.Closgen
+		}
+	}
+
+	*gen++
+	return pkg.Lookup(fmt.Sprintf("%s.%s%d", outer, prefix, *gen))
+}
+
+// NewClosureFunc creates a new Func to represent a function literal
+// within outerfn.
+func NewClosureFunc(pos src.XPos, outerfn *Func) *Func {
+	fn := NewFunc(pos)
+	fn.SetIsHiddenClosure(outerfn != nil)
+
+	fn.Nname = NewNameAt(pos, BlankNode.Sym())
+	fn.Nname.Func = fn
+	fn.Nname.Defn = fn
+
+	fn.OClosure = NewClosureExpr(pos, fn)
+
+	return fn
+}
+
+// NameClosure generates a unique for the given function literal,
+// which must have appeared within outerfn.
+func NameClosure(clo *ClosureExpr, outerfn *Func) {
+	name := clo.Func.Nname
+	if !IsBlank(name) {
+		base.FatalfAt(clo.Pos(), "closure already named: %v", name)
+	}
+
+	name.SetSym(closureName(outerfn))
+	MarkFunc(name)
+}
+
+// UseClosure checks that the ginen function literal has been setup
+// correctly, and then returns it as an expression.
+// It must be called after clo.Func.ClosureVars has been set.
+func UseClosure(clo *ClosureExpr, pkg *Package) Node {
+	fn := clo.Func
+	name := fn.Nname
+
+	if IsBlank(name) {
+		base.FatalfAt(fn.Pos(), "unnamed closure func: %v", fn)
+	}
+	// Caution: clo.Typecheck() is still 0 when UseClosure is called by
+	// tcClosure.
+	if fn.Typecheck() != 1 || name.Typecheck() != 1 {
+		base.FatalfAt(fn.Pos(), "missed typecheck: %v", fn)
+	}
+	if clo.Type() == nil || name.Type() == nil {
+		base.FatalfAt(fn.Pos(), "missing types: %v", fn)
+	}
+	if !types.Identical(clo.Type(), name.Type()) {
+		base.FatalfAt(fn.Pos(), "mismatched types: %v", fn)
+	}
+
+	if base.Flag.W > 1 {
+		s := fmt.Sprintf("new closure func: %v", fn)
+		Dump(s, fn)
+	}
+
+	if pkg != nil {
+		pkg.Decls = append(pkg.Decls, fn)
+	}
+
+	if false && IsTrivialClosure(clo) {
+		// TODO(mdempsky): Investigate if we can/should optimize this
+		// case. walkClosure already handles it later, but it could be
+		// useful to recognize earlier (e.g., it might allow multiple
+		// inlined calls to a function to share a common trivial closure
+		// func, rather than cloning it for each inlined call).
+	}
+
+	return clo
+}