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cmd/link, cmd/internal/obj: use encoding/binary for varint

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This code was written before the c2go toolchain conversion.
Replace the handwritten varint encoding routines
and the handwritten unsigned-to-signed conversions
with calls to encoding/binary.

Passes toolstash-check.

Change-Id: I30d7f408cde3772ee98a3825e83075c4e1ec96d8
Reviewed-on: https://go-review.googlesource.com/c/go/+/171769
Run-TryBot: Josh Bleecher Snyder <josharian@gmail.com>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
This commit is contained in:
Josh Bleecher Snyder 2019-04-12 09:29:43 -07:00
parent c70a7849af
commit 134ef176f0
2 changed files with 40 additions and 66 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

34
src/cmd/internal/obj/pcln.go
View File

@ -6,6 +6,7 @@ package obj
import (
"cmd/internal/src"
"encoding/binary"
"log"
)
@ -14,13 +15,6 @@ const (
EpilogueBegin // overload "is_stmt" to include epilogue_end
)
func addvarint(d *Pcdata, v uint32) {
for ; 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,
@ -52,8 +46,8 @@ func funcpctab(ctxt *Link, dst *Pcdata, func_ *LSym, desc string, valfunc func(*
ctxt.Logf("%6x %6d %v\n", uint64(pc), val, func_.Func.Text)
}
buf := make([]byte, binary.MaxVarintLen32)
started := false
var delta uint32
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)
@ -97,17 +91,15 @@ func funcpctab(ctxt *Link, dst *Pcdata, func_ *LSym, desc string, valfunc func(*
}
if started {
addvarint(dst, uint32((p.Pc-pc)/int64(ctxt.Arch.MinLC)))
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 = uint32(val) - uint32(oldval)
if delta>>31 != 0 {
delta = 1 | ^(delta << 1)
} else {
delta <<= 1
}
addvarint(dst, delta)
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)
@ -117,8 +109,14 @@ func funcpctab(ctxt *Link, dst *Pcdata, func_ *LSym, desc string, valfunc func(*
if dbg {
ctxt.Logf("%6x done\n", uint64(func_.Func.Text.Pc+func_.Size))
}
addvarint(dst, uint32((func_.Size-pc)/int64(ctxt.Arch.MinLC)))
addvarint(dst, 0) // terminator
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 {

72
src/cmd/link/internal/ld/pcln.go
View File

@ -9,6 +9,7 @@ import (
"cmd/internal/src"
"cmd/internal/sys"
"cmd/link/internal/sym"
"encoding/binary"
"log"
"os"
"path/filepath"
@ -17,22 +18,6 @@ import (
// iteration over encoded pcdata tables.
func getvarint(pp *[]byte) uint32 {
v := uint32(0)
p := *pp
for shift := 0; ; shift += 7 {
v |= uint32(p[0]&0x7F) << uint(shift)
tmp4 := p
p = p[1:]
if tmp4[0]&0x80 == 0 {
break
}
}
*pp = p
return v
}
func pciternext(it *Pciter) {
it.pc = it.nextpc
if it.done != 0 {
@ -44,21 +29,28 @@ func pciternext(it *Pciter) {
}
// value delta
v := getvarint(&it.p)
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 v == 0 && it.start == 0 {
if val == 0 && it.start == 0 {
it.done = 1
return
}
it.start = 0
dv := int32(v>>1) ^ (int32(v<<31) >> 31)
it.value += dv
it.value += int32(val)
// pc delta
v = getvarint(&it.p)
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 + v*it.pcscale
it.nextpc = it.pc + uint32(pc)*it.pcscale
}
func pciterinit(ctxt *Link, it *Pciter, d *sym.Pcdata) {
@ -73,28 +65,6 @@ func pciterinit(ctxt *Link, it *Pciter, d *sym.Pcdata) {
pciternext(it)
}
func addvarint(d *sym.Pcdata, val uint32) {
n := int32(0)
for v := val; v >= 0x80; v >>= 7 {
n++
}
n++
old := len(d.P)
for cap(d.P) < len(d.P)+int(n) {
d.P = append(d.P[:cap(d.P)], 0)
}
d.P = d.P[:old+int(n)]
p := d.P[old:]
var v uint32
for v = val; v >= 0x80; v >>= 7 {
p[0] = byte(v | 0x80)
p = p[1:]
}
p[0] = byte(v)
}
func addpctab(ctxt *Link, ftab *sym.Symbol, off int32, d *sym.Pcdata) int32 {
var start int32
if len(d.P) > 0 {
@ -128,6 +98,7 @@ func renumberfiles(ctxt *Link, files []*sym.Symbol, d *sym.Pcdata) {
numberfile(ctxt, f)
}
buf := make([]byte, binary.MaxVarintLen32)
newval := int32(-1)
var out sym.Pcdata
var it Pciter
@ -147,15 +118,20 @@ func renumberfiles(ctxt *Link, files []*sym.Symbol, d *sym.Pcdata) {
dv := val - newval
newval = val
v := (uint32(dv) << 1) ^ uint32(dv>>31)
addvarint(&out, v)
// value
n := binary.PutVarint(buf, int64(dv))
out.P = append(out.P, buf[:n]...)
// pc delta
addvarint(&out, (it.nextpc-it.pc)/it.pcscale)
pc := (it.nextpc - it.pc) / it.pcscale
n = binary.PutUvarint(buf, uint64(pc))
out.P = append(out.P, buf[:n]...)
}
// terminating value delta
addvarint(&out, 0)
// we want to write varint-encoded 0, which is just 0
out.P = append(out.P, 0)
*d = out
}