//go:build go1.16 && !go1.18
// +build go1.16,!go1.18
/*
* Copyright 2021 ByteDance Inc.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package loader
import (
`encoding`
`os`
`unsafe`
`github.com/bytedance/sonic/internal/rt`
)
const (
_Magic uint32 = 0xfffffffa
)
type pcHeader struct {
magic uint32 // 0xFFFFFFF0
pad1, pad2 uint8 // 0,0
minLC uint8 // min instruction size
ptrSize uint8 // size of a ptr in bytes
nfunc int // number of functions in the module
nfiles uint // number of entries in the file tab
funcnameOffset uintptr // offset to the funcnametab variable from pcHeader
cuOffset uintptr // offset to the cutab variable from pcHeader
filetabOffset uintptr // offset to the filetab variable from pcHeader
pctabOffset uintptr // offset to the pctab variable from pcHeader
pclnOffset uintptr // offset to the pclntab variable from pcHeader
}
type moduledata struct {
pcHeader *pcHeader
funcnametab []byte
cutab []uint32
filetab []byte
pctab []byte
pclntable []byte
ftab []funcTab
findfunctab uintptr
minpc, maxpc uintptr // first func address, last func address + last func size
text, etext uintptr // start/end of text, (etext-text) must be greater than MIN_FUNC
noptrdata, enoptrdata uintptr
data, edata uintptr
bss, ebss uintptr
noptrbss, enoptrbss uintptr
end, gcdata, gcbss uintptr
types, etypes uintptr
textsectmap []textSection // see runtime/symtab.go: textAddr()
typelinks []int32 // offsets from types
itablinks []*rt.GoItab
ptab []ptabEntry
pluginpath string
pkghashes []modulehash
modulename string
modulehashes []modulehash
hasmain uint8 // 1 if module contains the main function, 0 otherwise
gcdatamask, gcbssmask bitVector
typemap map[int32]*rt.GoType // offset to *_rtype in previous module
bad bool // module failed to load and should be ignored
next *moduledata
}
type _func struct {
entry uintptr // start pc, as offset from moduledata.text/pcHeader.textStart
nameOff int32 // function name, as index into moduledata.funcnametab.
args int32 // in/out args size
deferreturn uint32 // offset of start of a deferreturn call instruction from entry, if any.
pcsp uint32
pcfile uint32
pcln uint32
npcdata uint32
cuOffset uint32 // runtime.cutab offset of this function's CU
funcID uint8 // set for certain special runtime functions
_ [2]byte // pad
nfuncdata uint8 //
// The end of the struct is followed immediately by two variable-length
// arrays that reference the pcdata and funcdata locations for this
// function.
// pcdata contains the offset into moduledata.pctab for the start of
// that index's table. e.g.,
// &moduledata.pctab[_func.pcdata[_PCDATA_UnsafePoint]] is the start of
// the unsafe point table.
//
// An offset of 0 indicates that there is no table.
//
// pcdata [npcdata]uint32
// funcdata contains the offset past moduledata.gofunc which contains a
// pointer to that index's funcdata. e.g.,
// *(moduledata.gofunc + _func.funcdata[_FUNCDATA_ArgsPointerMaps]) is
// the argument pointer map.
//
// An offset of ^uint32(0) indicates that there is no entry.
//
// funcdata [nfuncdata]uint32
}
type funcTab struct {
entry uintptr
funcoff uintptr
}
type bitVector struct {
n int32 // # of bits
bytedata *uint8
}
type ptabEntry struct {
name int32
typ int32
}
type textSection struct {
vaddr uintptr // prelinked section vaddr
end uintptr // vaddr + section length
baseaddr uintptr // relocated section address
}
type modulehash struct {
modulename string
linktimehash string
runtimehash *string
}
// findfuncbucket is an array of these structures.
// Each bucket represents 4096 bytes of the text segment.
// Each subbucket represents 256 bytes of the text segment.
// To find a function given a pc, locate the bucket and subbucket for
// that pc. Add together the idx and subbucket value to obtain a
// function index. Then scan the functab array starting at that
// index to find the target function.
// This table uses 20 bytes for every 4096 bytes of code, or ~0.5% overhead.
type findfuncbucket struct {
idx uint32
_SUBBUCKETS [16]byte
}
type compilationUnit struct {
fileNames []string
}
// func name table format:
// nameOff[0] -> namePartA namePartB namePartC \x00
// nameOff[1] -> namePartA namePartB namePartC \x00
// ...
func makeFuncnameTab(funcs []Func) (tab []byte, offs []int32) {
offs = make([]int32, len(funcs))
offset := 0
for i, f := range funcs {
offs[i] = int32(offset)
a, b, c := funcNameParts(f.Name)
tab = append(tab, a...)
tab = append(tab, b...)
tab = append(tab, c...)
tab = append(tab, 0)
offset += len(a) + len(b) + len(c) + 1
}
return
}
// CU table format:
// cuOffsets[0] -> filetabOffset[0] filetabOffset[1] ... filetabOffset[len(CUs[0].fileNames)-1]
// cuOffsets[1] -> filetabOffset[len(CUs[0].fileNames)] ... filetabOffset[len(CUs[0].fileNames) + len(CUs[1].fileNames)-1]
// ...
//
// file name table format:
// filetabOffset[0] -> CUs[0].fileNames[0] \x00
// ...
// filetabOffset[len(CUs[0]-1)] -> CUs[0].fileNames[len(CUs[0].fileNames)-1] \x00
// ...
// filetabOffset[SUM(CUs,fileNames)-1] -> CUs[len(CU)-1].fileNames[len(CUs[len(CU)-1].fileNames)-1] \x00
func makeFilenametab(cus []compilationUnit) (cutab []uint32, filetab []byte, cuOffsets []uint32) {
cuOffsets = make([]uint32, len(cus))
cuOffset := 0
fileOffset := 0
for i, cu := range cus {
cuOffsets[i] = uint32(cuOffset)
for _, name := range cu.fileNames {
cutab = append(cutab, uint32(fileOffset))
fileOffset += len(name) + 1
filetab = append(filetab, name...)
filetab = append(filetab, 0)
}
cuOffset += len(cu.fileNames)
}
return
}
func writeFuncdata(out *[]byte, funcs []Func) (fstart int, funcdataOffs [][]uint32) {
fstart = len(*out)
*out = append(*out, byte(0))
offs := uint32(1)
funcdataOffs = make([][]uint32, len(funcs))
for i, f := range funcs {
var writer = func(fd encoding.BinaryMarshaler) {
var ab []byte
var err error
if fd != nil {
ab, err = fd.MarshalBinary()
if err != nil {
panic(err)
}
funcdataOffs[i] = append(funcdataOffs[i], offs)
} else {
ab = []byte{0}
funcdataOffs[i] = append(funcdataOffs[i], _INVALID_FUNCDATA_OFFSET)
}
*out = append(*out, ab...)
offs += uint32(len(ab))
}
writer(f.ArgsPointerMaps)
writer(f.LocalsPointerMaps)
writer(f.StackObjects)
writer(f.InlTree)
writer(f.OpenCodedDeferInfo)
writer(f.ArgInfo)
writer(f.ArgLiveInfo)
writer(f.WrapInfo)
}
return
}
func makeFtab(funcs []_func, lastFuncSize uint32) (ftab []funcTab, pclntabSize int64, startLocations []uint32) {
// Allocate space for the pc->func table. This structure consists of a pc offset
// and an offset to the func structure. After that, we have a single pc
// value that marks the end of the last function in the binary.
pclntabSize = int64(len(funcs)*2*int(_PtrSize) + int(_PtrSize))
startLocations = make([]uint32, len(funcs))
for i, f := range funcs {
pclntabSize = rnd(pclntabSize, int64(_PtrSize))
//writePCToFunc
startLocations[i] = uint32(pclntabSize)
pclntabSize += int64(uint8(_FUNC_SIZE) + f.nfuncdata*_PtrSize + uint8(f.npcdata)*4)
}
ftab = make([]funcTab, 0, len(funcs)+1)
// write a map of pc->func info offsets
for i, f := range funcs {
ftab = append(ftab, funcTab{uintptr(f.entry), uintptr(startLocations[i])})
}
// Final entry of table is just end pc offset.
lastFunc := funcs[len(funcs)-1]
ftab = append(ftab, funcTab{lastFunc.entry + uintptr(lastFuncSize), 0})
return
}
// Pcln table format: [...]funcTab + [...]_Func
func makePclntable(size int64, startLocations []uint32, funcs []_func, lastFuncSize uint32, pcdataOffs [][]uint32, funcdataAddr uintptr, funcdataOffs [][]uint32) (pclntab []byte) {
pclntab = make([]byte, size, size)
// write a map of pc->func info offsets
offs := 0
for i, f := range funcs {
byteOrder.PutUint64(pclntab[offs:offs+8], uint64(f.entry))
byteOrder.PutUint64(pclntab[offs+8:offs+16], uint64(startLocations[i]))
offs += 16
}
// Final entry of table is just end pc offset.
lastFunc := funcs[len(funcs)-1]
byteOrder.PutUint64(pclntab[offs:offs+8], uint64(lastFunc.entry)+uint64(lastFuncSize))
offs += 8
// write func info table
for i, f := range funcs {
off := startLocations[i]
// write _func structure to pclntab
byteOrder.PutUint64(pclntab[off:off+8], uint64(f.entry))
off += 8
byteOrder.PutUint32(pclntab[off:off+4], uint32(f.nameOff))
off += 4
byteOrder.PutUint32(pclntab[off:off+4], uint32(f.args))
off += 4
byteOrder.PutUint32(pclntab[off:off+4], uint32(f.deferreturn))
off += 4
byteOrder.PutUint32(pclntab[off:off+4], uint32(f.pcsp))
off += 4
byteOrder.PutUint32(pclntab[off:off+4], uint32(f.pcfile))
off += 4
byteOrder.PutUint32(pclntab[off:off+4], uint32(f.pcln))
off += 4
byteOrder.PutUint32(pclntab[off:off+4], uint32(f.npcdata))
off += 4
byteOrder.PutUint32(pclntab[off:off+4], uint32(f.cuOffset))
off += 4
pclntab[off] = f.funcID
// NOTICE: _[2]byte alignment
off += 3
pclntab[off] = f.nfuncdata
off += 1
// NOTICE: _func.pcdata always starts from PcUnsafePoint, which is index 3
for j := 3; j < len(pcdataOffs[i]); j++ {
byteOrder.PutUint32(pclntab[off:off+4], uint32(pcdataOffs[i][j]))
off += 4
}
off = uint32(rnd(int64(off), int64(_PtrSize)))
// funcdata refs as offsets from gofunc
for _, funcdata := range funcdataOffs[i] {
if funcdata == _INVALID_FUNCDATA_OFFSET {
byteOrder.PutUint64(pclntab[off:off+8], 0)
} else {
byteOrder.PutUint64(pclntab[off:off+8], uint64(funcdataAddr)+uint64(funcdata))
}
off += 8
}
}
return
}
// findfunc table used to map pc to belonging func,
// returns the index in the func table.
//
// All text section are divided into buckets sized _BUCKETSIZE(4K):
// every bucket is divided into _SUBBUCKETS sized _SUB_BUCKETSIZE(64),
// and it has a base idx to plus the offset stored in jth subbucket.
// see findfunc() in runtime/symtab.go
func writeFindfunctab(out *[]byte, ftab []funcTab) (start int) {
start = len(*out)
max := ftab[len(ftab)-1].entry
min := ftab[0].entry
nbuckets := (max - min + _BUCKETSIZE - 1) / _BUCKETSIZE
n := (max - min + _SUB_BUCKETSIZE - 1) / _SUB_BUCKETSIZE
tab := make([]findfuncbucket, 0, nbuckets)
var s, e = 0, 0
for i := 0; i<int(nbuckets); i++ {
var pc = min + uintptr((i+1)*_BUCKETSIZE)
// find the end func of the bucket
for ; e < len(ftab)-1 && ftab[e+1].entry <= pc; e++ {}
// store the start func of the bucket
var fb = findfuncbucket{idx: uint32(s)}
for j := 0; j<_SUBBUCKETS && (i*_SUBBUCKETS+j)<int(n); j++ {
pc = min + uintptr(i*_BUCKETSIZE) + uintptr((j+1)*_SUB_BUCKETSIZE)
var ss = s
// find the end func of the subbucket
for ; ss < len(ftab)-1 && ftab[ss+1].entry <= pc; ss++ {}
// store the start func of the subbucket
fb._SUBBUCKETS[j] = byte(uint32(s) - fb.idx)
s = ss
}
s = e
tab = append(tab, fb)
}
// write findfuncbucket
if len(tab) > 0 {
size := int(unsafe.Sizeof(findfuncbucket{}))*len(tab)
*out = append(*out, rt.BytesFrom(unsafe.Pointer(&tab[0]), size, size)...)
}
return
}
func makeModuledata(name string, filenames []string, funcs []Func, text []byte) (mod *moduledata) {
mod = new(moduledata)
mod.modulename = name
// make filename table
cu := make([]string, 0, len(filenames))
for _, f := range filenames {
cu = append(cu, f)
}
cutab, filetab, cuOffs := makeFilenametab([]compilationUnit{{cu}})
mod.cutab = cutab
mod.filetab = filetab
// make funcname table
funcnametab, nameOffs := makeFuncnameTab(funcs)
mod.funcnametab = funcnametab
// mmap() text and funcdata segements
p := os.Getpagesize()
size := int(rnd(int64(len(text)), int64(p)))
addr := mmap(size)
// copy the machine code
s := rt.BytesFrom(unsafe.Pointer(addr), len(text), size)
copy(s, text)
// make it executable
mprotect(addr, size)
// make pcdata table
// NOTICE: _func only use offset to index pcdata, thus no need mmap() pcdata
pctab, pcdataOffs, _funcs := makePctab(funcs, addr, cuOffs, nameOffs)
mod.pctab = pctab
// write func data
// NOTICE: _func use mod.gofunc+offset to directly point funcdata, thus need cache funcdata
// TODO: estimate accurate capacity
cache := make([]byte, 0, len(funcs)*int(_PtrSize))
fstart, funcdataOffs := writeFuncdata(&cache, funcs)
// make pc->func (binary search) func table
lastFuncsize := funcs[len(funcs)-1].TextSize
ftab, pclntSize, startLocations := makeFtab(_funcs, lastFuncsize)
mod.ftab = ftab
// write pc->func (modmap) findfunc table
ffstart := writeFindfunctab(&cache, ftab)
// cache funcdata and findfuncbucket
moduleCache.Lock()
moduleCache.m[mod] = cache
moduleCache.Unlock()
mod.findfunctab = uintptr(rt.IndexByte(cache, ffstart))
funcdataAddr := uintptr(rt.IndexByte(cache, fstart))
// make pclnt table
pclntab := makePclntable(pclntSize, startLocations, _funcs, lastFuncsize, pcdataOffs, funcdataAddr, funcdataOffs)
mod.pclntable = pclntab
// assign addresses
mod.text = addr
mod.etext = addr + uintptr(size)
mod.minpc = addr
mod.maxpc = addr + uintptr(len(text))
// make pc header
mod.pcHeader = &pcHeader {
magic : _Magic,
minLC : _MinLC,
ptrSize : _PtrSize,
nfunc : len(funcs),
nfiles: uint(len(cu)),
funcnameOffset: getOffsetOf(moduledata{}, "funcnametab"),
cuOffset: getOffsetOf(moduledata{}, "cutab"),
filetabOffset: getOffsetOf(moduledata{}, "filetab"),
pctabOffset: getOffsetOf(moduledata{}, "pctab"),
pclnOffset: getOffsetOf(moduledata{}, "pclntable"),
}
// sepecial case: gcdata and gcbss must by non-empty
mod.gcdata = uintptr(unsafe.Pointer(&emptyByte))
mod.gcbss = uintptr(unsafe.Pointer(&emptyByte))
return
}
// makePctab generates pcdelta->valuedelta tables for functions,
// and returns the table and the entry offset of every kind pcdata in the table.
func makePctab(funcs []Func, addr uintptr, cuOffset []uint32, nameOffset []int32) (pctab []byte, pcdataOffs [][]uint32, _funcs []_func) {
_funcs = make([]_func, len(funcs))
// Pctab offsets of 0 are considered invalid in the runtime. We respect
// that by just padding a single byte at the beginning of runtime.pctab,
// that way no real offsets can be zero.
pctab = make([]byte, 1, 12*len(funcs)+1)
pcdataOffs = make([][]uint32, len(funcs))
for i, f := range funcs {
_f := &_funcs[i]
var writer = func(pc *Pcdata) {
var ab []byte
var err error
if pc != nil {
ab, err = pc.MarshalBinary()
if err != nil {
panic(err)
}
pcdataOffs[i] = append(pcdataOffs[i], uint32(len(pctab)))
} else {
ab = []byte{0}
pcdataOffs[i] = append(pcdataOffs[i], _PCDATA_INVALID_OFFSET)
}
pctab = append(pctab, ab...)
}
if f.Pcsp != nil {
_f.pcsp = uint32(len(pctab))
}
writer(f.Pcsp)
if f.Pcfile != nil {
_f.pcfile = uint32(len(pctab))
}
writer(f.Pcfile)
if f.Pcline != nil {
_f.pcln = uint32(len(pctab))
}
writer(f.Pcline)
writer(f.PcUnsafePoint)
writer(f.PcStackMapIndex)
writer(f.PcInlTreeIndex)
writer(f.PcArgLiveIndex)
_f.entry = addr + uintptr(f.EntryOff)
_f.nameOff = nameOffset[i]
_f.args = f.ArgsSize
_f.deferreturn = f.DeferReturn
// NOTICE: _func.pcdata is always as [PCDATA_UnsafePoint(0) : PCDATA_ArgLiveIndex(3)]
_f.npcdata = uint32(_N_PCDATA)
_f.cuOffset = cuOffset[i]
_f.funcID = f.ID
_f.nfuncdata = uint8(_N_FUNCDATA)
}
return
}
func registerFunction(name string, pc uintptr, textSize uintptr, fp int, args int, size uintptr, argptrs uintptr, localptrs uintptr) {}