Current File : //usr/local/go/src/go/internal/gcimporter/support.go
// 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" }
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