mirror of
https://github.com/cwinfo/matterbridge.git
synced 2024-11-27 07:41:36 +00:00
282 lines
8.0 KiB
Go
282 lines
8.0 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 "log"
|
|
|
|
func addvarint(ctxt *Link, d *Pcdata, val uint32) {
|
|
var v uint32
|
|
for v = val; v >= 0x80; v >>= 7 {
|
|
d.P = append(d.P, uint8(v|0x80))
|
|
}
|
|
d.P = append(d.P, uint8(v))
|
|
}
|
|
|
|
// 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{}) {
|
|
// To debug a specific function, uncomment lines and change name.
|
|
dbg := 0
|
|
|
|
//if func_.Name == "main.main" || desc == "pctospadj" {
|
|
// dbg = 1
|
|
//}
|
|
|
|
ctxt.Debugpcln += int32(dbg)
|
|
|
|
dst.P = dst.P[:0]
|
|
|
|
if ctxt.Debugpcln != 0 {
|
|
ctxt.Logf("funcpctab %s [valfunc=%s]\n", func_.Name, desc)
|
|
}
|
|
|
|
val := int32(-1)
|
|
oldval := val
|
|
if func_.Text == nil {
|
|
ctxt.Debugpcln -= int32(dbg)
|
|
return
|
|
}
|
|
|
|
pc := func_.Text.Pc
|
|
|
|
if ctxt.Debugpcln != 0 {
|
|
ctxt.Logf("%6x %6d %v\n", uint64(pc), val, func_.Text)
|
|
}
|
|
|
|
started := int32(0)
|
|
var delta uint32
|
|
for p := 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 != 0 {
|
|
val = valfunc(ctxt, func_, val, p, 1, arg)
|
|
if ctxt.Debugpcln != 0 {
|
|
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 ctxt.Debugpcln != 0 {
|
|
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 ctxt.Debugpcln != 0 {
|
|
ctxt.Logf("%6x %6d %v\n", uint64(p.Pc), val, p)
|
|
}
|
|
|
|
if started != 0 {
|
|
addvarint(ctxt, dst, uint32((p.Pc-pc)/int64(ctxt.Arch.MinLC)))
|
|
pc = p.Pc
|
|
}
|
|
|
|
delta = uint32(val) - uint32(oldval)
|
|
if delta>>31 != 0 {
|
|
delta = 1 | ^(delta << 1)
|
|
} else {
|
|
delta <<= 1
|
|
}
|
|
addvarint(ctxt, dst, delta)
|
|
oldval = val
|
|
started = 1
|
|
val = valfunc(ctxt, func_, val, p, 1, arg)
|
|
}
|
|
|
|
if started != 0 {
|
|
if ctxt.Debugpcln != 0 {
|
|
ctxt.Logf("%6x done\n", uint64(func_.Text.Pc+func_.Size))
|
|
}
|
|
addvarint(ctxt, dst, uint32((func_.Size-pc)/int64(ctxt.Arch.MinLC)))
|
|
addvarint(ctxt, dst, 0) // terminator
|
|
}
|
|
|
|
if ctxt.Debugpcln != 0 {
|
|
ctxt.Logf("wrote %d bytes to %p\n", len(dst.P), dst)
|
|
for i := 0; i < len(dst.P); i++ {
|
|
ctxt.Logf(" %02x", dst.P[i])
|
|
}
|
|
ctxt.Logf("\n")
|
|
}
|
|
|
|
ctxt.Debugpcln -= int32(dbg)
|
|
}
|
|
|
|
// pctofileline computes either the file number (arg == 0)
|
|
// or the line number (arg == 1) to use at p.
|
|
// Because p->lineno 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.As == AUSEFIELD || p.Lineno == 0 || phase == 1 {
|
|
return oldval
|
|
}
|
|
f, l := linkgetline(ctxt, p.Lineno)
|
|
if f == nil {
|
|
// print("getline failed for %s %v\n", ctxt->cursym->name, p);
|
|
return oldval
|
|
}
|
|
|
|
if arg == nil {
|
|
return l
|
|
}
|
|
pcln := arg.(*Pcln)
|
|
|
|
if f == pcln.Lastfile {
|
|
return int32(pcln.Lastindex)
|
|
}
|
|
|
|
for i, file := range pcln.File {
|
|
if file == f {
|
|
pcln.Lastfile = f
|
|
pcln.Lastindex = i
|
|
return int32(i)
|
|
}
|
|
}
|
|
i := len(pcln.File)
|
|
pcln.File = append(pcln.File, f)
|
|
pcln.Lastfile = f
|
|
pcln.Lastindex = i
|
|
return int32(i)
|
|
}
|
|
|
|
// 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)
|
|
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)
|
|
log.Fatalf("bad code")
|
|
}
|
|
|
|
return int32(p.To.Offset)
|
|
}
|
|
|
|
func linkpcln(ctxt *Link, cursym *LSym) {
|
|
ctxt.Cursym = cursym
|
|
|
|
pcln := new(Pcln)
|
|
cursym.Pcln = pcln
|
|
|
|
npcdata := 0
|
|
nfuncdata := 0
|
|
for p := cursym.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)
|
|
|
|
// tabulate which pc and func data we have.
|
|
havepc := make([]uint32, (npcdata+31)/32)
|
|
havefunc := make([]uint32, (nfuncdata+31)/32)
|
|
for p := cursym.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 {
|
|
var i int
|
|
for p := cursym.Text; p != nil; p = p.Link {
|
|
if p.As == AFUNCDATA {
|
|
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
|
|
}
|
|
}
|
|
}
|
|
}
|
|
}
|