1// Copyright 2019 The Go Authors. All rights reserved.
2// Use of this source code is governed by a BSD-style
3// license that can be found in the LICENSE file.
4
5package goobj
6
7import (
8	"bytes"
9	"encoding/binary"
10	"internal/abi"
11)
12
13// CUFileIndex is used to index the filenames that are stored in the
14// per-package/per-CU FileList.
15type CUFileIndex uint32
16
17// FuncInfo is serialized as a symbol (aux symbol). The symbol data is
18// the binary encoding of the struct below.
19type FuncInfo struct {
20	Args      uint32
21	Locals    uint32
22	FuncID    abi.FuncID
23	FuncFlag  abi.FuncFlag
24	StartLine int32
25	File      []CUFileIndex
26	InlTree   []InlTreeNode
27}
28
29func (a *FuncInfo) Write(w *bytes.Buffer) {
30	writeUint8 := func(x uint8) {
31		w.WriteByte(x)
32	}
33	var b [4]byte
34	writeUint32 := func(x uint32) {
35		binary.LittleEndian.PutUint32(b[:], x)
36		w.Write(b[:])
37	}
38
39	writeUint32(a.Args)
40	writeUint32(a.Locals)
41	writeUint8(uint8(a.FuncID))
42	writeUint8(uint8(a.FuncFlag))
43	writeUint8(0) // pad to uint32 boundary
44	writeUint8(0)
45	writeUint32(uint32(a.StartLine))
46
47	writeUint32(uint32(len(a.File)))
48	for _, f := range a.File {
49		writeUint32(uint32(f))
50	}
51	writeUint32(uint32(len(a.InlTree)))
52	for i := range a.InlTree {
53		a.InlTree[i].Write(w)
54	}
55}
56
57// FuncInfoLengths is a cache containing a roadmap of offsets and
58// lengths for things within a serialized FuncInfo. Each length field
59// stores the number of items (e.g. files, inltree nodes, etc), and the
60// corresponding "off" field stores the byte offset of the start of
61// the items in question.
62type FuncInfoLengths struct {
63	NumFile     uint32
64	FileOff     uint32
65	NumInlTree  uint32
66	InlTreeOff  uint32
67	Initialized bool
68}
69
70func (*FuncInfo) ReadFuncInfoLengths(b []byte) FuncInfoLengths {
71	var result FuncInfoLengths
72
73	// Offset to the number of the file table. This value is determined by counting
74	// the number of bytes until we write funcdataoff to the file.
75	const numfileOff = 16
76	result.NumFile = binary.LittleEndian.Uint32(b[numfileOff:])
77	result.FileOff = numfileOff + 4
78
79	numinltreeOff := result.FileOff + 4*result.NumFile
80	result.NumInlTree = binary.LittleEndian.Uint32(b[numinltreeOff:])
81	result.InlTreeOff = numinltreeOff + 4
82
83	result.Initialized = true
84
85	return result
86}
87
88func (*FuncInfo) ReadArgs(b []byte) uint32 { return binary.LittleEndian.Uint32(b) }
89
90func (*FuncInfo) ReadLocals(b []byte) uint32 { return binary.LittleEndian.Uint32(b[4:]) }
91
92func (*FuncInfo) ReadFuncID(b []byte) abi.FuncID { return abi.FuncID(b[8]) }
93
94func (*FuncInfo) ReadFuncFlag(b []byte) abi.FuncFlag { return abi.FuncFlag(b[9]) }
95
96func (*FuncInfo) ReadStartLine(b []byte) int32 { return int32(binary.LittleEndian.Uint32(b[12:])) }
97
98func (*FuncInfo) ReadFile(b []byte, filesoff uint32, k uint32) CUFileIndex {
99	return CUFileIndex(binary.LittleEndian.Uint32(b[filesoff+4*k:]))
100}
101
102func (*FuncInfo) ReadInlTree(b []byte, inltreeoff uint32, k uint32) InlTreeNode {
103	const inlTreeNodeSize = 4 * 6
104	var result InlTreeNode
105	result.Read(b[inltreeoff+k*inlTreeNodeSize:])
106	return result
107}
108
109// InlTreeNode is the serialized form of FileInfo.InlTree.
110type InlTreeNode struct {
111	Parent   int32
112	File     CUFileIndex
113	Line     int32
114	Func     SymRef
115	ParentPC int32
116}
117
118func (inl *InlTreeNode) Write(w *bytes.Buffer) {
119	var b [4]byte
120	writeUint32 := func(x uint32) {
121		binary.LittleEndian.PutUint32(b[:], x)
122		w.Write(b[:])
123	}
124	writeUint32(uint32(inl.Parent))
125	writeUint32(uint32(inl.File))
126	writeUint32(uint32(inl.Line))
127	writeUint32(inl.Func.PkgIdx)
128	writeUint32(inl.Func.SymIdx)
129	writeUint32(uint32(inl.ParentPC))
130}
131
132// Read an InlTreeNode from b, return the remaining bytes.
133func (inl *InlTreeNode) Read(b []byte) []byte {
134	readUint32 := func() uint32 {
135		x := binary.LittleEndian.Uint32(b)
136		b = b[4:]
137		return x
138	}
139	inl.Parent = int32(readUint32())
140	inl.File = CUFileIndex(readUint32())
141	inl.Line = int32(readUint32())
142	inl.Func = SymRef{readUint32(), readUint32()}
143	inl.ParentPC = int32(readUint32())
144	return b
145}
146