Current File : //usr/local/go119/src/cmd/internal/goobj/funcinfo.go
// Copyright 2019 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.
package goobj
import (
"bytes"
"cmd/internal/objabi"
"encoding/binary"
)
// CUFileIndex is used to index the filenames that are stored in the
// per-package/per-CU FileList.
type CUFileIndex uint32
// FuncInfo is serialized as a symbol (aux symbol). The symbol data is
// the binary encoding of the struct below.
type FuncInfo struct {
Args uint32
Locals uint32
FuncID objabi.FuncID
FuncFlag objabi.FuncFlag
File []CUFileIndex
InlTree []InlTreeNode
}
func (a *FuncInfo) Write(w *bytes.Buffer) {
writeUint8 := func(x uint8) {
w.WriteByte(x)
}
var b [4]byte
writeUint32 := func(x uint32) {
binary.LittleEndian.PutUint32(b[:], x)
w.Write(b[:])
}
writeUint32(a.Args)
writeUint32(a.Locals)
writeUint8(uint8(a.FuncID))
writeUint8(uint8(a.FuncFlag))
writeUint8(0) // pad to uint32 boundary
writeUint8(0)
writeUint32(uint32(len(a.File)))
for _, f := range a.File {
writeUint32(uint32(f))
}
writeUint32(uint32(len(a.InlTree)))
for i := range a.InlTree {
a.InlTree[i].Write(w)
}
}
// FuncInfoLengths is a cache containing a roadmap of offsets and
// lengths for things within a serialized FuncInfo. Each length field
// stores the number of items (e.g. files, inltree nodes, etc), and the
// corresponding "off" field stores the byte offset of the start of
// the items in question.
type FuncInfoLengths struct {
NumFile uint32
FileOff uint32
NumInlTree uint32
InlTreeOff uint32
Initialized bool
}
func (*FuncInfo) ReadFuncInfoLengths(b []byte) FuncInfoLengths {
var result FuncInfoLengths
// Offset to the number of the file table. This value is determined by counting
// the number of bytes until we write funcdataoff to the file.
const numfileOff = 12
result.NumFile = binary.LittleEndian.Uint32(b[numfileOff:])
result.FileOff = numfileOff + 4
numinltreeOff := result.FileOff + 4*result.NumFile
result.NumInlTree = binary.LittleEndian.Uint32(b[numinltreeOff:])
result.InlTreeOff = numinltreeOff + 4
result.Initialized = true
return result
}
func (*FuncInfo) ReadArgs(b []byte) uint32 { return binary.LittleEndian.Uint32(b) }
func (*FuncInfo) ReadLocals(b []byte) uint32 { return binary.LittleEndian.Uint32(b[4:]) }
func (*FuncInfo) ReadFuncID(b []byte) objabi.FuncID { return objabi.FuncID(b[8]) }
func (*FuncInfo) ReadFuncFlag(b []byte) objabi.FuncFlag { return objabi.FuncFlag(b[9]) }
func (*FuncInfo) ReadFile(b []byte, filesoff uint32, k uint32) CUFileIndex {
return CUFileIndex(binary.LittleEndian.Uint32(b[filesoff+4*k:]))
}
func (*FuncInfo) ReadInlTree(b []byte, inltreeoff uint32, k uint32) InlTreeNode {
const inlTreeNodeSize = 4 * 6
var result InlTreeNode
result.Read(b[inltreeoff+k*inlTreeNodeSize:])
return result
}
// InlTreeNode is the serialized form of FileInfo.InlTree.
type InlTreeNode struct {
Parent int32
File CUFileIndex
Line int32
Func SymRef
ParentPC int32
}
func (inl *InlTreeNode) Write(w *bytes.Buffer) {
var b [4]byte
writeUint32 := func(x uint32) {
binary.LittleEndian.PutUint32(b[:], x)
w.Write(b[:])
}
writeUint32(uint32(inl.Parent))
writeUint32(uint32(inl.File))
writeUint32(uint32(inl.Line))
writeUint32(inl.Func.PkgIdx)
writeUint32(inl.Func.SymIdx)
writeUint32(uint32(inl.ParentPC))
}
// Read an InlTreeNode from b, return the remaining bytes.
func (inl *InlTreeNode) Read(b []byte) []byte {
readUint32 := func() uint32 {
x := binary.LittleEndian.Uint32(b)
b = b[4:]
return x
}
inl.Parent = int32(readUint32())
inl.File = CUFileIndex(readUint32())
inl.Line = int32(readUint32())
inl.Func = SymRef{readUint32(), readUint32()}
inl.ParentPC = int32(readUint32())
return b
}
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