mirror of
https://github.com/superseriousbusiness/gotosocial.git
synced 2024-12-05 18:12:46 +00:00
414 lines
12 KiB
Go
414 lines
12 KiB
Go
// Copyright 2013 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 obj
|
|
|
|
import (
|
|
"github.com/twitchyliquid64/golang-asm/goobj"
|
|
"encoding/binary"
|
|
"log"
|
|
)
|
|
|
|
// funcpctab writes to dst a pc-value table mapping the code in func to the values
|
|
// returned by valfunc parameterized by arg. The invocation of valfunc to update the
|
|
// current value is, for each p,
|
|
//
|
|
// val = valfunc(func, val, p, 0, arg);
|
|
// record val as value at p->pc;
|
|
// val = valfunc(func, val, p, 1, arg);
|
|
//
|
|
// where func is the function, val is the current value, p is the instruction being
|
|
// considered, and arg can be used to further parameterize valfunc.
|
|
func funcpctab(ctxt *Link, dst *Pcdata, func_ *LSym, desc string, valfunc func(*Link, *LSym, int32, *Prog, int32, interface{}) int32, arg interface{}) {
|
|
dbg := desc == ctxt.Debugpcln
|
|
|
|
dst.P = dst.P[:0]
|
|
|
|
if dbg {
|
|
ctxt.Logf("funcpctab %s [valfunc=%s]\n", func_.Name, desc)
|
|
}
|
|
|
|
val := int32(-1)
|
|
oldval := val
|
|
if func_.Func.Text == nil {
|
|
return
|
|
}
|
|
|
|
pc := func_.Func.Text.Pc
|
|
|
|
if dbg {
|
|
ctxt.Logf("%6x %6d %v\n", uint64(pc), val, func_.Func.Text)
|
|
}
|
|
|
|
buf := make([]byte, binary.MaxVarintLen32)
|
|
started := false
|
|
for p := func_.Func.Text; p != nil; p = p.Link {
|
|
// Update val. If it's not changing, keep going.
|
|
val = valfunc(ctxt, func_, val, p, 0, arg)
|
|
|
|
if val == oldval && started {
|
|
val = valfunc(ctxt, func_, val, p, 1, arg)
|
|
if dbg {
|
|
ctxt.Logf("%6x %6s %v\n", uint64(p.Pc), "", p)
|
|
}
|
|
continue
|
|
}
|
|
|
|
// If the pc of the next instruction is the same as the
|
|
// pc of this instruction, this instruction is not a real
|
|
// instruction. Keep going, so that we only emit a delta
|
|
// for a true instruction boundary in the program.
|
|
if p.Link != nil && p.Link.Pc == p.Pc {
|
|
val = valfunc(ctxt, func_, val, p, 1, arg)
|
|
if dbg {
|
|
ctxt.Logf("%6x %6s %v\n", uint64(p.Pc), "", p)
|
|
}
|
|
continue
|
|
}
|
|
|
|
// The table is a sequence of (value, pc) pairs, where each
|
|
// pair states that the given value is in effect from the current position
|
|
// up to the given pc, which becomes the new current position.
|
|
// To generate the table as we scan over the program instructions,
|
|
// we emit a "(value" when pc == func->value, and then
|
|
// each time we observe a change in value we emit ", pc) (value".
|
|
// When the scan is over, we emit the closing ", pc)".
|
|
//
|
|
// The table is delta-encoded. The value deltas are signed and
|
|
// transmitted in zig-zag form, where a complement bit is placed in bit 0,
|
|
// and the pc deltas are unsigned. Both kinds of deltas are sent
|
|
// as variable-length little-endian base-128 integers,
|
|
// where the 0x80 bit indicates that the integer continues.
|
|
|
|
if dbg {
|
|
ctxt.Logf("%6x %6d %v\n", uint64(p.Pc), val, p)
|
|
}
|
|
|
|
if started {
|
|
pcdelta := (p.Pc - pc) / int64(ctxt.Arch.MinLC)
|
|
n := binary.PutUvarint(buf, uint64(pcdelta))
|
|
dst.P = append(dst.P, buf[:n]...)
|
|
pc = p.Pc
|
|
}
|
|
|
|
delta := val - oldval
|
|
n := binary.PutVarint(buf, int64(delta))
|
|
dst.P = append(dst.P, buf[:n]...)
|
|
oldval = val
|
|
started = true
|
|
val = valfunc(ctxt, func_, val, p, 1, arg)
|
|
}
|
|
|
|
if started {
|
|
if dbg {
|
|
ctxt.Logf("%6x done\n", uint64(func_.Func.Text.Pc+func_.Size))
|
|
}
|
|
v := (func_.Size - pc) / int64(ctxt.Arch.MinLC)
|
|
if v < 0 {
|
|
ctxt.Diag("negative pc offset: %v", v)
|
|
}
|
|
n := binary.PutUvarint(buf, uint64(v))
|
|
dst.P = append(dst.P, buf[:n]...)
|
|
// add terminating varint-encoded 0, which is just 0
|
|
dst.P = append(dst.P, 0)
|
|
}
|
|
|
|
if dbg {
|
|
ctxt.Logf("wrote %d bytes to %p\n", len(dst.P), dst)
|
|
for _, p := range dst.P {
|
|
ctxt.Logf(" %02x", p)
|
|
}
|
|
ctxt.Logf("\n")
|
|
}
|
|
}
|
|
|
|
// pctofileline computes either the file number (arg == 0)
|
|
// or the line number (arg == 1) to use at p.
|
|
// Because p.Pos applies to p, phase == 0 (before p)
|
|
// takes care of the update.
|
|
func pctofileline(ctxt *Link, sym *LSym, oldval int32, p *Prog, phase int32, arg interface{}) int32 {
|
|
if p.As == ATEXT || p.As == ANOP || p.Pos.Line() == 0 || phase == 1 {
|
|
return oldval
|
|
}
|
|
f, l := getFileIndexAndLine(ctxt, p.Pos)
|
|
if arg == nil {
|
|
return l
|
|
}
|
|
pcln := arg.(*Pcln)
|
|
pcln.UsedFiles[goobj.CUFileIndex(f)] = struct{}{}
|
|
return int32(f)
|
|
}
|
|
|
|
// pcinlineState holds the state used to create a function's inlining
|
|
// tree and the PC-value table that maps PCs to nodes in that tree.
|
|
type pcinlineState struct {
|
|
globalToLocal map[int]int
|
|
localTree InlTree
|
|
}
|
|
|
|
// addBranch adds a branch from the global inlining tree in ctxt to
|
|
// the function's local inlining tree, returning the index in the local tree.
|
|
func (s *pcinlineState) addBranch(ctxt *Link, globalIndex int) int {
|
|
if globalIndex < 0 {
|
|
return -1
|
|
}
|
|
|
|
localIndex, ok := s.globalToLocal[globalIndex]
|
|
if ok {
|
|
return localIndex
|
|
}
|
|
|
|
// Since tracebacks don't include column information, we could
|
|
// use one node for multiple calls of the same function on the
|
|
// same line (e.g., f(x) + f(y)). For now, we use one node for
|
|
// each inlined call.
|
|
call := ctxt.InlTree.nodes[globalIndex]
|
|
call.Parent = s.addBranch(ctxt, call.Parent)
|
|
localIndex = len(s.localTree.nodes)
|
|
s.localTree.nodes = append(s.localTree.nodes, call)
|
|
s.globalToLocal[globalIndex] = localIndex
|
|
return localIndex
|
|
}
|
|
|
|
func (s *pcinlineState) setParentPC(ctxt *Link, globalIndex int, pc int32) {
|
|
localIndex, ok := s.globalToLocal[globalIndex]
|
|
if !ok {
|
|
// We know where to unwind to when we need to unwind a body identified
|
|
// by globalIndex. But there may be no instructions generated by that
|
|
// body (it's empty, or its instructions were CSEd with other things, etc.).
|
|
// In that case, we don't need an unwind entry.
|
|
// TODO: is this really right? Seems to happen a whole lot...
|
|
return
|
|
}
|
|
s.localTree.setParentPC(localIndex, pc)
|
|
}
|
|
|
|
// pctoinline computes the index into the local inlining tree to use at p.
|
|
// If p is not the result of inlining, pctoinline returns -1. Because p.Pos
|
|
// applies to p, phase == 0 (before p) takes care of the update.
|
|
func (s *pcinlineState) pctoinline(ctxt *Link, sym *LSym, oldval int32, p *Prog, phase int32, arg interface{}) int32 {
|
|
if phase == 1 {
|
|
return oldval
|
|
}
|
|
|
|
posBase := ctxt.PosTable.Pos(p.Pos).Base()
|
|
if posBase == nil {
|
|
return -1
|
|
}
|
|
|
|
globalIndex := posBase.InliningIndex()
|
|
if globalIndex < 0 {
|
|
return -1
|
|
}
|
|
|
|
if s.globalToLocal == nil {
|
|
s.globalToLocal = make(map[int]int)
|
|
}
|
|
|
|
return int32(s.addBranch(ctxt, globalIndex))
|
|
}
|
|
|
|
// pctospadj computes the sp adjustment in effect.
|
|
// It is oldval plus any adjustment made by p itself.
|
|
// The adjustment by p takes effect only after p, so we
|
|
// apply the change during phase == 1.
|
|
func pctospadj(ctxt *Link, sym *LSym, oldval int32, p *Prog, phase int32, arg interface{}) int32 {
|
|
if oldval == -1 { // starting
|
|
oldval = 0
|
|
}
|
|
if phase == 0 {
|
|
return oldval
|
|
}
|
|
if oldval+p.Spadj < -10000 || oldval+p.Spadj > 1100000000 {
|
|
ctxt.Diag("overflow in spadj: %d + %d = %d", oldval, p.Spadj, oldval+p.Spadj)
|
|
ctxt.DiagFlush()
|
|
log.Fatalf("bad code")
|
|
}
|
|
|
|
return oldval + p.Spadj
|
|
}
|
|
|
|
// pctopcdata computes the pcdata value in effect at p.
|
|
// A PCDATA instruction sets the value in effect at future
|
|
// non-PCDATA instructions.
|
|
// Since PCDATA instructions have no width in the final code,
|
|
// it does not matter which phase we use for the update.
|
|
func pctopcdata(ctxt *Link, sym *LSym, oldval int32, p *Prog, phase int32, arg interface{}) int32 {
|
|
if phase == 0 || p.As != APCDATA || p.From.Offset != int64(arg.(uint32)) {
|
|
return oldval
|
|
}
|
|
if int64(int32(p.To.Offset)) != p.To.Offset {
|
|
ctxt.Diag("overflow in PCDATA instruction: %v", p)
|
|
ctxt.DiagFlush()
|
|
log.Fatalf("bad code")
|
|
}
|
|
|
|
return int32(p.To.Offset)
|
|
}
|
|
|
|
func linkpcln(ctxt *Link, cursym *LSym) {
|
|
pcln := &cursym.Func.Pcln
|
|
pcln.UsedFiles = make(map[goobj.CUFileIndex]struct{})
|
|
|
|
npcdata := 0
|
|
nfuncdata := 0
|
|
for p := cursym.Func.Text; p != nil; p = p.Link {
|
|
// Find the highest ID of any used PCDATA table. This ignores PCDATA table
|
|
// that consist entirely of "-1", since that's the assumed default value.
|
|
// From.Offset is table ID
|
|
// To.Offset is data
|
|
if p.As == APCDATA && p.From.Offset >= int64(npcdata) && p.To.Offset != -1 { // ignore -1 as we start at -1, if we only see -1, nothing changed
|
|
npcdata = int(p.From.Offset + 1)
|
|
}
|
|
// Find the highest ID of any FUNCDATA table.
|
|
// From.Offset is table ID
|
|
if p.As == AFUNCDATA && p.From.Offset >= int64(nfuncdata) {
|
|
nfuncdata = int(p.From.Offset + 1)
|
|
}
|
|
}
|
|
|
|
pcln.Pcdata = make([]Pcdata, npcdata)
|
|
pcln.Pcdata = pcln.Pcdata[:npcdata]
|
|
pcln.Funcdata = make([]*LSym, nfuncdata)
|
|
pcln.Funcdataoff = make([]int64, nfuncdata)
|
|
pcln.Funcdataoff = pcln.Funcdataoff[:nfuncdata]
|
|
|
|
funcpctab(ctxt, &pcln.Pcsp, cursym, "pctospadj", pctospadj, nil)
|
|
funcpctab(ctxt, &pcln.Pcfile, cursym, "pctofile", pctofileline, pcln)
|
|
funcpctab(ctxt, &pcln.Pcline, cursym, "pctoline", pctofileline, nil)
|
|
|
|
// Check that all the Progs used as inline markers are still reachable.
|
|
// See issue #40473.
|
|
inlMarkProgs := make(map[*Prog]struct{}, len(cursym.Func.InlMarks))
|
|
for _, inlMark := range cursym.Func.InlMarks {
|
|
inlMarkProgs[inlMark.p] = struct{}{}
|
|
}
|
|
for p := cursym.Func.Text; p != nil; p = p.Link {
|
|
if _, ok := inlMarkProgs[p]; ok {
|
|
delete(inlMarkProgs, p)
|
|
}
|
|
}
|
|
if len(inlMarkProgs) > 0 {
|
|
ctxt.Diag("one or more instructions used as inline markers are no longer reachable")
|
|
}
|
|
|
|
pcinlineState := new(pcinlineState)
|
|
funcpctab(ctxt, &pcln.Pcinline, cursym, "pctoinline", pcinlineState.pctoinline, nil)
|
|
for _, inlMark := range cursym.Func.InlMarks {
|
|
pcinlineState.setParentPC(ctxt, int(inlMark.id), int32(inlMark.p.Pc))
|
|
}
|
|
pcln.InlTree = pcinlineState.localTree
|
|
if ctxt.Debugpcln == "pctoinline" && len(pcln.InlTree.nodes) > 0 {
|
|
ctxt.Logf("-- inlining tree for %s:\n", cursym)
|
|
dumpInlTree(ctxt, pcln.InlTree)
|
|
ctxt.Logf("--\n")
|
|
}
|
|
|
|
// tabulate which pc and func data we have.
|
|
havepc := make([]uint32, (npcdata+31)/32)
|
|
havefunc := make([]uint32, (nfuncdata+31)/32)
|
|
for p := cursym.Func.Text; p != nil; p = p.Link {
|
|
if p.As == AFUNCDATA {
|
|
if (havefunc[p.From.Offset/32]>>uint64(p.From.Offset%32))&1 != 0 {
|
|
ctxt.Diag("multiple definitions for FUNCDATA $%d", p.From.Offset)
|
|
}
|
|
havefunc[p.From.Offset/32] |= 1 << uint64(p.From.Offset%32)
|
|
}
|
|
|
|
if p.As == APCDATA && p.To.Offset != -1 {
|
|
havepc[p.From.Offset/32] |= 1 << uint64(p.From.Offset%32)
|
|
}
|
|
}
|
|
|
|
// pcdata.
|
|
for i := 0; i < npcdata; i++ {
|
|
if (havepc[i/32]>>uint(i%32))&1 == 0 {
|
|
continue
|
|
}
|
|
funcpctab(ctxt, &pcln.Pcdata[i], cursym, "pctopcdata", pctopcdata, interface{}(uint32(i)))
|
|
}
|
|
|
|
// funcdata
|
|
if nfuncdata > 0 {
|
|
for p := cursym.Func.Text; p != nil; p = p.Link {
|
|
if p.As != AFUNCDATA {
|
|
continue
|
|
}
|
|
i := int(p.From.Offset)
|
|
pcln.Funcdataoff[i] = p.To.Offset
|
|
if p.To.Type != TYPE_CONST {
|
|
// TODO: Dedup.
|
|
//funcdata_bytes += p->to.sym->size;
|
|
pcln.Funcdata[i] = p.To.Sym
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
// PCIter iterates over encoded pcdata tables.
|
|
type PCIter struct {
|
|
p []byte
|
|
PC uint32
|
|
NextPC uint32
|
|
PCScale uint32
|
|
Value int32
|
|
start bool
|
|
Done bool
|
|
}
|
|
|
|
// newPCIter creates a PCIter with a scale factor for the PC step size.
|
|
func NewPCIter(pcScale uint32) *PCIter {
|
|
it := new(PCIter)
|
|
it.PCScale = pcScale
|
|
return it
|
|
}
|
|
|
|
// Next advances it to the Next pc.
|
|
func (it *PCIter) Next() {
|
|
it.PC = it.NextPC
|
|
if it.Done {
|
|
return
|
|
}
|
|
if len(it.p) == 0 {
|
|
it.Done = true
|
|
return
|
|
}
|
|
|
|
// Value delta
|
|
val, n := binary.Varint(it.p)
|
|
if n <= 0 {
|
|
log.Fatalf("bad Value varint in pciterNext: read %v", n)
|
|
}
|
|
it.p = it.p[n:]
|
|
|
|
if val == 0 && !it.start {
|
|
it.Done = true
|
|
return
|
|
}
|
|
|
|
it.start = false
|
|
it.Value += int32(val)
|
|
|
|
// pc delta
|
|
pc, n := binary.Uvarint(it.p)
|
|
if n <= 0 {
|
|
log.Fatalf("bad pc varint in pciterNext: read %v", n)
|
|
}
|
|
it.p = it.p[n:]
|
|
|
|
it.NextPC = it.PC + uint32(pc)*it.PCScale
|
|
}
|
|
|
|
// init prepares it to iterate over p,
|
|
// and advances it to the first pc.
|
|
func (it *PCIter) Init(p []byte) {
|
|
it.p = p
|
|
it.PC = 0
|
|
it.NextPC = 0
|
|
it.Value = -1
|
|
it.start = true
|
|
it.Done = false
|
|
it.Next()
|
|
}
|