summaryrefslogtreecommitdiffstats
path: root/src/go/internal/gcimporter/support.go
blob: b8bb14dc490e2a1a47e24adc60be69304e7414a3 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
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" }