1 files changed, 130 insertions, 0 deletions
diff --git a/src/go/internal/gcimporter/support.go b/src/go/internal/gcimporter/support.go
new file mode 100644
index 0000000..b8bb14d
--- /dev/null
+++ b/src/go/internal/gcimporter/support.go
@@ -0,0 +1,130 @@
+// Copyright 2015 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.
+
+// This file implements support functionality for iimport.go.
+
+package gcimporter
+
+import (
+	"fmt"
+	"go/token"
+	"go/types"
+	"sync"
+)
+
+func errorf(format string, args ...interface{}) {
+	panic(fmt.Sprintf(format, args...))
+}
+
+// deltaNewFile is a magic line delta offset indicating a new file.
+// We use -64 because it is rare; see issue 20080 and CL 41619.
+// -64 is the smallest int that fits in a single byte as a varint.
+const deltaNewFile = -64
+
+// Synthesize a token.Pos
+type fakeFileSet struct {
+	fset  *token.FileSet
+	files map[string]*token.File
+}
+
+func (s *fakeFileSet) pos(file string, line, column int) token.Pos {
+	// TODO(mdempsky): Make use of column.
+
+	// Since we don't know the set of needed file positions, we
+	// reserve maxlines positions per file.
+	const maxlines = 64 * 1024
+	f := s.files[file]
+	if f == nil {
+		f = s.fset.AddFile(file, -1, maxlines)
+		s.files[file] = f
+		// Allocate the fake linebreak indices on first use.
+		// TODO(adonovan): opt: save ~512KB using a more complex scheme?
+		fakeLinesOnce.Do(func() {
+			fakeLines = make([]int, maxlines)
+			for i := range fakeLines {
+				fakeLines[i] = i
+			}
+		})
+		f.SetLines(fakeLines)
+	}
+
+	if line > maxlines {
+		line = 1
+	}
+
+	// Treat the file as if it contained only newlines
+	// and column=1: use the line number as the offset.
+	return f.Pos(line - 1)
+}
+
+var (
+	fakeLines     []int
+	fakeLinesOnce sync.Once
+)
+
+func chanDir(d int) types.ChanDir {
+	// tag values must match the constants in cmd/compile/internal/gc/go.go
+	switch d {
+	case 1 /* Crecv */ :
+		return types.RecvOnly
+	case 2 /* Csend */ :
+		return types.SendOnly
+	case 3 /* Cboth */ :
+		return types.SendRecv
+	default:
+		errorf("unexpected channel dir %d", d)
+		return 0
+	}
+}
+
+var predeclared = []types.Type{
+	// basic types
+	types.Typ[types.Bool],
+	types.Typ[types.Int],
+	types.Typ[types.Int8],
+	types.Typ[types.Int16],
+	types.Typ[types.Int32],
+	types.Typ[types.Int64],
+	types.Typ[types.Uint],
+	types.Typ[types.Uint8],
+	types.Typ[types.Uint16],
+	types.Typ[types.Uint32],
+	types.Typ[types.Uint64],
+	types.Typ[types.Uintptr],
+	types.Typ[types.Float32],
+	types.Typ[types.Float64],
+	types.Typ[types.Complex64],
+	types.Typ[types.Complex128],
+	types.Typ[types.String],
+
+	// basic type aliases
+	types.Universe.Lookup("byte").Type(),
+	types.Universe.Lookup("rune").Type(),
+
+	// error
+	types.Universe.Lookup("error").Type(),
+
+	// untyped types
+	types.Typ[types.UntypedBool],
+	types.Typ[types.UntypedInt],
+	types.Typ[types.UntypedRune],
+	types.Typ[types.UntypedFloat],
+	types.Typ[types.UntypedComplex],
+	types.Typ[types.UntypedString],
+	types.Typ[types.UntypedNil],
+
+	// package unsafe
+	types.Typ[types.UnsafePointer],
+
+	// invalid type
+	types.Typ[types.Invalid], // only appears in packages with errors
+
+	// used internally by gc; never used by this package or in .a files
+	anyType{},
+}
+
+type anyType struct{}
+
+func (t anyType) Underlying() types.Type { return t }
+func (t anyType) String() string         { return "any" }