[dev.link] debug/gosym: fix file mappings
CL 246497 introduced bugs in gosym that the long tests caught. These two
bugs were:
1) In 1.16, 0 is now a valid file number from pcfile tables.
2) Also, in 1.16, when we scan all functions looking for a pc/file pair,
the values returned from pcfile are no longer the direct offset into
the file table. Rather, the values from pcfile are the offset into
the cu->file look-up table.
This CL fixes those two issues.
Change-Id: I0cd280bdcaeda89faaf9fac41809abdb87734499
Reviewed-on: https://go-review.googlesource.com/c/go/+/248317
Reviewed-by: Cherry Zhang <cherryyz@google.com>
Reviewed-by: Austin Clements <austin@google.com>
Reviewed-by: Than McIntosh <thanm@google.com>
diff --git a/src/debug/gosym/pclntab.go b/src/debug/gosym/pclntab.go
index e383ea4..21edddd 100644
--- a/src/debug/gosym/pclntab.go
+++ b/src/debug/gosym/pclntab.go
@@ -59,9 +59,12 @@
nfunctab uint32
filetab []byte
nfiletab uint32
- fileMap map[string]uint32
funcNames map[uint32]string // cache the function names
strings map[uint32]string // interned substrings of Data, keyed by offset
+ // fileMap varies depending on the version of the object file.
+ // For ver12, it maps the name to the index in the file table.
+ // For ver116, it maps the name to the offset in filetab.
+ fileMap map[string]uint32
}
// NOTE(rsc): This is wrong for GOARCH=arm, which uses a quantum of 4,
@@ -388,7 +391,7 @@
// to file number. Since most functions come from a single file, these
// are usually short and quick to scan. If a file match is found, then the
// code goes to the expense of looking for a simultaneous line number match.
-func (t *LineTable) findFileLine(entry uint64, filetab, linetab uint32, filenum, line int32) uint64 {
+func (t *LineTable) findFileLine(entry uint64, filetab, linetab uint32, filenum, line int32, cutab []byte) uint64 {
if filetab == 0 || linetab == 0 {
return 0
}
@@ -401,8 +404,12 @@
linePC := entry
fileStartPC := filePC
for t.step(&fp, &filePC, &fileVal, filePC == entry) {
- if fileVal == filenum && fileStartPC < filePC {
- // fileVal is in effect starting at fileStartPC up to
+ fileIndex := fileVal
+ if t.version == ver116 {
+ fileIndex = int32(t.binary.Uint32(cutab[fileVal*4:]))
+ }
+ if fileIndex == filenum && fileStartPC < filePC {
+ // fileIndex is in effect starting at fileStartPC up to
// but not including filePC, and it's the file we want.
// Run the PC table looking for a matching line number
// or until we reach filePC.
@@ -457,13 +464,16 @@
entry := t.uintptr(f)
filetab := t.binary.Uint32(f[t.ptrsize+4*4:])
fno := t.pcvalue(filetab, entry, pc)
- if fno <= 0 {
- return ""
- }
if t.version == ver12 {
+ if fno <= 0 {
+ return ""
+ }
return t.string(t.binary.Uint32(t.filetab[4*fno:]))
}
// Go ≥ 1.16
+ if fno < 0 { // 0 is valid for ≥ 1.16
+ return ""
+ }
cuoff := t.binary.Uint32(f[t.ptrsize+7*4:])
if fnoff := t.binary.Uint32(t.cutab[(cuoff+uint32(fno))*4:]); fnoff != ^uint32(0) {
return t.stringFrom(t.filetab, fnoff)
@@ -471,7 +481,7 @@
return ""
}
-// go12LineToPC maps a (file, line) pair to a program counter for the Go 1.2 pcln table.
+// go12LineToPC maps a (file, line) pair to a program counter for the Go 1.2/1.16 pcln table.
func (t *LineTable) go12LineToPC(file string, line int) (pc uint64) {
defer func() {
if recover() != nil {
@@ -480,20 +490,25 @@
}()
t.initFileMap()
- filenum := t.fileMap[file]
- if filenum == 0 {
+ filenum, ok := t.fileMap[file]
+ if !ok {
return 0
}
// Scan all functions.
// If this turns out to be a bottleneck, we could build a map[int32][]int32
// mapping file number to a list of functions with code from that file.
+ var cutab []byte
for i := uint32(0); i < t.nfunctab; i++ {
f := t.funcdata[t.uintptr(t.functab[2*t.ptrsize*i+t.ptrsize:]):]
entry := t.uintptr(f)
filetab := t.binary.Uint32(f[t.ptrsize+4*4:])
linetab := t.binary.Uint32(f[t.ptrsize+5*4:])
- pc := t.findFileLine(entry, filetab, linetab, int32(filenum), int32(line))
+ if t.version == ver116 {
+ cuoff := t.binary.Uint32(f[t.ptrsize+7*4:]) * 4
+ cutab = t.cutab[cuoff:]
+ }
+ pc := t.findFileLine(entry, filetab, linetab, int32(filenum), int32(line), cutab)
if pc != 0 {
return pc
}
@@ -518,10 +533,10 @@
}
} else {
var pos uint32
- for i := uint32(1); i < t.nfiletab; i++ {
+ for i := uint32(0); i < t.nfiletab; i++ {
s := t.stringFrom(t.filetab, pos)
+ m[s] = pos
pos += uint32(len(s) + 1)
- m[s] = i
}
}
t.fileMap = m
