golang support 代码
文件路径：/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"
"internal/pkgbits"
"sync"
)
func assert(b bool) {
if !b {
panic("assertion failed")
}
}
func errorf(format string, args ...any) {
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]*fileInfo
}
type fileInfo struct {
file *token.File
lastline int
}
const maxlines = 64 * 1024
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. We delay calling token.File.SetLines until
/ all positions have been calculated (by way of fakeFileSet.setLines), so
/ that we can avoid setting unnecessary lines. See also golang/go#46586.
f := s.files[file]
if f == nil {
f = &fileInfo{file: s.fset.AddFile(file, -1, maxlines)}
s.files[file] = f
}
if line > maxlines {
line = 1
}
if line > f.lastline {
f.lastline = line
}
/ Return a fake position assuming that f.file consists only of newlines.
return token.Pos(f.file.Base() + line - 1)
}
func (s *fakeFileSet) setLines() {
fakeLinesOnce.Do(func() {
fakeLines = make([]int, maxlines)
for i := range fakeLines {
fakeLines[i] = i
}
})
for _, f := range s.files {
f.file.SetLines(fakeLines[:f.lastline])
}
}
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
/ not to be confused with the universe any
anyType{},
/ comparable
types.Universe.Lookup("comparable").Type(),
/ any
types.Universe.Lookup("any").Type(),
}
type anyType struct{}
func (t anyType) Underlying() types.Type { return t }
func (t anyType) String() string { return "any" }
/ See cmd/compile/internal/noder.derivedInfo.
type derivedInfo struct {
idx pkgbits.Index
needed bool
}
/ See cmd/compile/internal/noder.typeInfo.
type typeInfo struct {
idx pkgbits.Index
derived bool
}