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cmd/internal/obj: simplify filename handling

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The old Go object file format used linker symbols like "gofile..foo"
to record references to the filename "foo". But the current object
file format has a dedicated section for file names, so we don't need
these useless prefixes anymore.

Also, change DWARF generation to pass around the src.Pos directly,
rather than the old file symbols, which it just turned back into a
file index before writing out anyway.

Finally, directly record the FileIndex into src.PosBase, so that we
can skip the map lookups.

Change-Id: Ia4a5ebfa95da271f2522e45befdb9f137c16d373
Reviewed-on: https://go-review.googlesource.com/c/go/+/523378
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
Reviewed-by: Cherry Mui <cherryyz@google.com>
Auto-Submit: Matthew Dempsky <mdempsky@google.com>
This commit is contained in:
Matthew Dempsky 2023-08-28 05:13:03 -07:00 committed by Gopher Robot
parent 06f420fc19
commit c9bb7ce2d7
11 changed files with 103 additions and 121 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

6
src/cmd/compile/internal/dwarfgen/dwinl.go
View File

@ -273,13 +273,11 @@ func insertInlCall(dwcalls *dwarf.InlCalls, inlIdx int, imap map[int]int) int {
// Create new entry for this inline
inlinedFn := base.Ctxt.InlTree.InlinedFunction(inlIdx)
callXPos := base.Ctxt.InlTree.CallPos(inlIdx)
callPos := base.Ctxt.PosTable.Pos(callXPos)
callFileSym := base.Ctxt.Lookup(callPos.Base().SymFilename())
callPos := base.Ctxt.InnermostPos(callXPos)
absFnSym := base.Ctxt.DwFixups.AbsFuncDwarfSym(inlinedFn)
ic := dwarf.InlCall{
InlIndex: inlIdx,
CallFile: callFileSym,
CallLine: uint32(callPos.RelLine()),
CallPos: callPos,
AbsFunSym: absFnSym,
Root: parCallIdx == -1,
}

23
src/cmd/internal/dwarf/dwarf.go
View File

@ -9,6 +9,7 @@ package dwarf
import (
"bytes"
"cmd/internal/src"
"errors"
"fmt"
"internal/buildcfg"
@ -85,13 +86,12 @@ type Range struct {
type FnState struct {
Name string
Info Sym
Filesym Sym
Loc Sym
Ranges Sym
Absfn Sym
StartPC Sym
StartPos src.Pos
Size int64
StartLine int32
External bool
Scopes []Scope
InlCalls InlCalls
@ -166,11 +166,8 @@ type InlCall struct {
// index into ctx.InlTree describing the call inlined here
InlIndex int
// Symbol of file containing inlined call site (really *obj.LSym).
CallFile Sym
// Line number of inlined call site.
CallLine uint32
// Position of the inlined call site.
CallPos src.Pos
// Dwarf abstract subroutine symbol (really *obj.LSym).
AbsFunSym Sym
@ -202,7 +199,6 @@ type Context interface {
RecordDclReference(from Sym, to Sym, dclIdx int, inlIndex int)
RecordChildDieOffsets(s Sym, vars []*Var, offsets []int32)
AddString(s Sym, v string)
AddFileRef(s Sym, f interface{})
Logf(format string, args ...interface{})
}
@ -1246,7 +1242,8 @@ func PutAbstractFunc(ctxt Context, s *FnState) error {
// DW_AT_inlined value
putattr(ctxt, s.Absfn, abbrev, DW_FORM_data1, DW_CLS_CONSTANT, int64(DW_INL_inlined), nil)
putattr(ctxt, s.Absfn, abbrev, DW_FORM_udata, DW_CLS_CONSTANT, int64(s.StartLine), nil)
// TODO(mdempsky): Shouldn't we write out StartPos.FileIndex() too?
putattr(ctxt, s.Absfn, abbrev, DW_FORM_udata, DW_CLS_CONSTANT, int64(s.StartPos.RelLine()), nil)
var ev int64
if s.External {
@ -1335,9 +1332,9 @@ func putInlinedFunc(ctxt Context, s *FnState, callIdx int) error {
}
// Emit call file, line attrs.
ctxt.AddFileRef(s.Info, ic.CallFile)
putattr(ctxt, s.Info, abbrev, DW_FORM_data4, DW_CLS_CONSTANT, int64(1+ic.CallPos.FileIndex()), nil) // 1-based file table
form := int(expandPseudoForm(DW_FORM_udata_pseudo))
putattr(ctxt, s.Info, abbrev, form, DW_CLS_CONSTANT, int64(ic.CallLine), nil)
putattr(ctxt, s.Info, abbrev, form, DW_CLS_CONSTANT, int64(ic.CallPos.RelLine()), nil)
// Variables associated with this inlined routine instance.
vars := ic.InlVars
@ -1438,8 +1435,8 @@ func PutDefaultFunc(ctxt Context, s *FnState, isWrapper bool) error {
if isWrapper {
putattr(ctxt, s.Info, abbrev, DW_FORM_flag, DW_CLS_FLAG, int64(1), 0)
} else {
ctxt.AddFileRef(s.Info, s.Filesym)
putattr(ctxt, s.Info, abbrev, DW_FORM_udata, DW_CLS_CONSTANT, int64(s.StartLine), nil)
putattr(ctxt, s.Info, abbrev, DW_FORM_data4, DW_CLS_CONSTANT, int64(1+s.StartPos.FileIndex()), nil) // 1-based file index
putattr(ctxt, s.Info, abbrev, DW_FORM_udata, DW_CLS_CONSTANT, int64(s.StartPos.RelLine()), nil)
var ev int64
if s.External {

49
src/cmd/internal/obj/dwarf.go
View File

@ -48,7 +48,7 @@ func (ctxt *Link) generateDebugLinesSymbol(s, lines *LSym) {
line := int64(1)
pc := s.Func().Text.Pc
var lastpc int64 // last PC written to line table, not last PC in func
name := ""
fileIndex := 1
prologue, wrotePrologue := false, false
// Walk the progs, generating the DWARF table.
for p := s.Func().Text; p != nil; p = p.Link {
@ -58,15 +58,15 @@ func (ctxt *Link) generateDebugLinesSymbol(s, lines *LSym) {
continue
}
newStmt := p.Pos.IsStmt() != src.PosNotStmt
newName, newLine := ctxt.getFileSymbolAndLine(p.Pos)
newFileIndex, newLine := ctxt.getFileIndexAndLine(p.Pos)
newFileIndex++ // 1 indexing for the table
// Output debug info.
wrote := false
if name != newName {
newFile := ctxt.PosTable.FileIndex(newName) + 1 // 1 indexing for the table.
if newFileIndex != fileIndex {
dctxt.AddUint8(lines, dwarf.DW_LNS_set_file)
dwarf.Uleb128put(dctxt, lines, int64(newFile))
name = newName
dwarf.Uleb128put(dctxt, lines, int64(newFileIndex))
fileIndex = newFileIndex
wrote = true
}
if prologue && !wrotePrologue {
@ -258,16 +258,6 @@ func (c dwCtxt) AddDWARFAddrSectionOffset(s dwarf.Sym, t interface{}, ofs int64)
r.Type = objabi.R_DWARFSECREF
}
func (c dwCtxt) AddFileRef(s dwarf.Sym, f interface{}) {
ls := s.(*LSym)
rsym := f.(*LSym)
fidx := c.Link.PosTable.FileIndex(rsym.Name)
// Note the +1 here -- the value we're writing is going to be an
// index into the DWARF line table file section, whose entries
// are numbered starting at 1, not 0.
ls.WriteInt(c.Link, ls.Size, 4, int64(fidx+1))
}
func (c dwCtxt) CurrentOffset(s dwarf.Sym) int64 {
ls := s.(*LSym)
return ls.Size
@ -329,17 +319,13 @@ func (s *LSym) Length(dwarfContext interface{}) int64 {
return s.Size
}
// fileSymbol returns a symbol corresponding to the source file of the
// first instruction (prog) of the specified function. This will
// presumably be the file in which the function is defined.
func (ctxt *Link) fileSymbol(fn *LSym) *LSym {
p := fn.Func().Text
if p != nil {
f, _ := ctxt.getFileSymbolAndLine(p.Pos)
fsym := ctxt.Lookup(f)
return fsym
// textPos returns the source position of the first instruction (prog)
// of the specified function.
func textPos(fn *LSym) src.XPos {
if p := fn.Func().Text; p != nil {
return p.Pos
}
return nil
return src.NoXPos
}
// populateDWARF fills in the DWARF Debugging Information Entries for
@ -362,17 +348,19 @@ func (ctxt *Link) populateDWARF(curfn Func, s *LSym) {
}
var err error
dwctxt := dwCtxt{ctxt}
filesym := ctxt.fileSymbol(s)
startPos := ctxt.InnermostPos(textPos(s))
if !startPos.IsKnown() || startPos.RelLine() != uint(s.Func().StartLine) {
panic("bad startPos")
}
fnstate := &dwarf.FnState{
Name: s.Name,
Info: info,
Filesym: filesym,
Loc: loc,
Ranges: ranges,
Absfn: absfunc,
StartPC: s,
Size: s.Size,
StartLine: s.Func().StartLine,
StartPos: startPos,
External: !s.Static(),
Scopes: scopes,
InlCalls: inlcalls,
@ -434,13 +422,12 @@ func (ctxt *Link) DwarfAbstractFunc(curfn Func, s *LSym) {
s.NewFuncInfo()
}
scopes, _ := ctxt.DebugInfo(s, absfn, curfn)
_, startLine := ctxt.getFileSymbolAndLine(curfn.Pos())
dwctxt := dwCtxt{ctxt}
fnstate := dwarf.FnState{
Name: s.Name,
Info: absfn,
Absfn: absfn,
StartLine: startLine,
StartPos: ctxt.InnermostPos(curfn.Pos()),
External: !s.Static(),
Scopes: scopes,
UseBASEntries: ctxt.UseBASEntries,

18
src/cmd/internal/obj/line.go
View File

@ -14,22 +14,14 @@ func (ctxt *Link) AddImport(pkg string, fingerprint goobj.FingerprintType) {
ctxt.Imports = append(ctxt.Imports, goobj.ImportedPkg{Pkg: pkg, Fingerprint: fingerprint})
}
// getFileSymbolAndLine returns the relative file symbol and relative line
// number for a position (i.e., as adjusted by a //line directive). This is the
// file/line visible in the final binary (pcfile, pcln, etc).
func (ctxt *Link) getFileSymbolAndLine(xpos src.XPos) (f string, l int32) {
pos := ctxt.InnermostPos(xpos)
if !pos.IsKnown() {
pos = src.Pos{}
}
return pos.SymFilename(), int32(pos.RelLine())
}
// getFileIndexAndLine returns the relative file index (local to the CU), and
// the relative line number for a position (i.e., as adjusted by a //line
// directive). This is the file/line visible in the final binary (pcfile, pcln,
// etc).
func (ctxt *Link) getFileIndexAndLine(xpos src.XPos) (int, int32) {
f, l := ctxt.getFileSymbolAndLine(xpos)
return ctxt.PosTable.FileIndex(f), l
pos := ctxt.InnermostPos(xpos)
if !pos.IsKnown() {
pos = src.Pos{}
}
return pos.FileIndex(), int32(pos.RelLine())
}

12
src/cmd/internal/obj/line_test.go
View File

@ -31,9 +31,15 @@ func TestGetFileSymbolAndLine(t *testing.T) {
}
for _, test := range tests {
f, l := ctxt.getFileSymbolAndLine(ctxt.PosTable.XPos(test.pos))
got := fmt.Sprintf("%s:%d", f, l)
if got != src.FileSymPrefix+test.want {
fileIndex, line := ctxt.getFileIndexAndLine(ctxt.PosTable.XPos(test.pos))
file := "??"
if fileIndex >= 0 {
file = ctxt.PosTable.FileTable()[fileIndex]
}
got := fmt.Sprintf("%s:%d", file, line)
if got != test.want {
t.Errorf("ctxt.getFileSymbolAndLine(%v) = %q, want %q", test.pos, got, test.want)
}
}

2
src/cmd/internal/obj/plist.go
View File

@ -198,7 +198,7 @@ func (ctxt *Link) InitTextSym(s *LSym, flag int, start src.XPos) {
// startLine should be the same line number that would be displayed via
// pcln, etc for the declaration (i.e., relative line number, as
// adjusted by //line).
_, startLine := ctxt.getFileSymbolAndLine(start)
_, startLine := ctxt.getFileIndexAndLine(start)
s.Func().FuncID = objabi.GetFuncID(s.Name, flag&WRAPPER != 0 || flag&ABIWRAPPER != 0)
s.Func().FuncFlag = ctxt.toFuncFlag(flag)

4
src/cmd/internal/obj/sym.go
View File

@ -449,10 +449,6 @@ func (ctxt *Link) traverseFuncAux(flag traverseFlag, fsym *LSym, fn func(parent
if call.Func != nil {
fn(fsym, call.Func)
}
f, _ := ctxt.getFileSymbolAndLine(call.Pos)
if filesym := ctxt.Lookup(f); filesym != nil {
fn(fsym, filesym)
}
}
auxsyms := []*LSym{fninfo.dwarfRangesSym, fninfo.dwarfLocSym, fninfo.dwarfDebugLinesSym, fninfo.dwarfInfoSym, fninfo.WasmImportSym, fninfo.sehUnwindInfoSym}

51
src/cmd/internal/src/pos.go
View File

@ -116,9 +116,9 @@ func (p Pos) RelCol() uint {
// AbsFilename() returns the absolute filename recorded with the position's base.
func (p Pos) AbsFilename() string { return p.base.AbsFilename() }
// SymFilename() returns the absolute filename recorded with the position's base,
// prefixed by FileSymPrefix to make it appropriate for use as a linker symbol.
func (p Pos) SymFilename() string { return p.base.SymFilename() }
// FileIndex returns the file index of the position's base's absolute
// filename within the PosTable that it was registered.
func (p Pos) FileIndex() int { return p.base.FileIndex() }
func (p Pos) String() string {
return p.Format(true, true)
@ -193,9 +193,9 @@ type PosBase struct {
pos Pos // position at which the relative position is (line, col)
filename string // file name used to open source file, for error messages
absFilename string // absolute file name, for PC-Line tables
symFilename string // cached symbol file name, to avoid repeated string concatenation
line, col uint // relative line, column number at pos
inl int // inlining index (see cmd/internal/obj/inl.go)
fileIndex int // index of absFilename within PosTable.FileTable
}
// NewFileBase returns a new *PosBase for a file with the given (relative and
@ -204,10 +204,10 @@ func NewFileBase(filename, absFilename string) *PosBase {
base := &PosBase{
filename: filename,
absFilename: absFilename,
symFilename: FileSymPrefix + absFilename,
line: 1,
col: 1,
inl: -1,
fileIndex: -1,
}
base.pos = MakePos(base, 1, 1)
return base
@ -220,24 +220,22 @@ func NewFileBase(filename, absFilename string) *PosBase {
//
// at position pos.
func NewLinePragmaBase(pos Pos, filename, absFilename string, line, col uint) *PosBase {
return &PosBase{pos, filename, absFilename, FileSymPrefix + absFilename, line, col, -1}
return &PosBase{pos, filename, absFilename, line, col, -1, -1}
}
// NewInliningBase returns a copy of the old PosBase with the given inlining
// index. If old == nil, the resulting PosBase has no filename.
func NewInliningBase(old *PosBase, inlTreeIndex int) *PosBase {
if old == nil {
base := &PosBase{line: 1, col: 1, inl: inlTreeIndex}
base.pos = MakePos(base, 1, 1)
return base
// NewInliningBase returns a copy of the orig PosBase with the given inlining
// index. If orig == nil, NewInliningBase panics.
func NewInliningBase(orig *PosBase, inlTreeIndex int) *PosBase {
if orig == nil {
panic("no old PosBase")
}
copy := *old
base := &copy
base := *orig
base.inl = inlTreeIndex
if old == old.pos.base {
base.pos.base = base
base.fileIndex = -1
if orig == orig.pos.base {
base.pos.base = &base
}
return base
return &base
}
var noPos Pos
@ -269,16 +267,21 @@ func (b *PosBase) AbsFilename() string {
return ""
}
// FileSymPrefix is the linker symbol prefix that used to be used for
// linker pseudo-symbols representing file names.
const FileSymPrefix = "gofile.."
// SymFilename returns the absolute filename recorded with the base,
// prefixed by FileSymPrefix to make it appropriate for use as a linker symbol.
// If b is nil, SymFilename returns FileSymPrefix + "??".
func (b *PosBase) SymFilename() string {
// FileIndex returns the index of the base's absolute filename within
// its PosTable's FileTable. It panics if it hasn't been registered
// with a PosTable. If b == nil, the result is -1.
func (b *PosBase) FileIndex() int {
if b != nil {
return b.symFilename
if b.fileIndex < 0 {
panic("PosBase has no file index")
}
return b.fileIndex
}
return FileSymPrefix + "??"
return -1
}
// Line returns the line number recorded with the base.

51
src/cmd/internal/src/xpos.go
View File

@ -124,25 +124,40 @@ type PosTable struct {
// XPos returns the corresponding XPos for the given pos,
// adding pos to t if necessary.
func (t *PosTable) XPos(pos Pos) XPos {
m := t.indexMap
if m == nil {
// Create new list and map and populate with nil
// base so that NoPos always gets index 0.
return XPos{t.baseIndex(pos.base), pos.lico}
}
func (t *PosTable) baseIndex(base *PosBase) int32 {
if base == nil {
return 0
}
if i, ok := t.indexMap[base]; ok {
return int32(i)
}
if base.fileIndex >= 0 {
panic("PosBase already registered with a PosTable")
}
if t.indexMap == nil {
t.baseList = append(t.baseList, nil)
m = map[*PosBase]int{nil: 0}
t.indexMap = m
t.indexMap = make(map[*PosBase]int)
t.nameMap = make(map[string]int)
}
i, ok := m[pos.base]
i := len(t.baseList)
t.indexMap[base] = i
t.baseList = append(t.baseList, base)
fileIndex, ok := t.nameMap[base.absFilename]
if !ok {
i = len(t.baseList)
t.baseList = append(t.baseList, pos.base)
t.indexMap[pos.base] = i
if _, ok := t.nameMap[pos.base.symFilename]; !ok {
t.nameMap[pos.base.symFilename] = len(t.nameMap)
}
fileIndex = len(t.nameMap)
t.nameMap[base.absFilename] = fileIndex
}
return XPos{int32(i), pos.lico}
base.fileIndex = fileIndex
return int32(i)
}
// Pos returns the corresponding Pos for the given p.
@ -155,14 +170,6 @@ func (t *PosTable) Pos(p XPos) Pos {
return Pos{base, p.lico}
}
// FileIndex returns the index of the given filename(symbol) in the PosTable, or -1 if not found.
func (t *PosTable) FileIndex(filename string) int {
if v, ok := t.nameMap[filename]; ok {
return v
}
return -1
}
// FileTable returns a slice of all files used to build this package.
func (t *PosTable) FileTable() []string {
// Create a LUT of the global package level file indices. This table is what

4
src/cmd/internal/src/xpos_test.go
View File

@ -62,8 +62,8 @@ func TestConversion(t *testing.T) {
}
}
if len(tab.baseList) != len(tab.indexMap) {
t.Errorf("table length discrepancy: %d != %d", len(tab.baseList), len(tab.indexMap))
if len(tab.baseList) != 1+len(tab.indexMap) { // indexMap omits nil
t.Errorf("table length discrepancy: %d != 1+%d", len(tab.baseList), len(tab.indexMap))
}
const wantLen = 4

4
src/cmd/link/internal/ld/dwarf.go
View File

@ -154,10 +154,6 @@ func (c dwctxt) Logf(format string, args ...interface{}) {
// At the moment these interfaces are only used in the compiler.
func (c dwctxt) AddFileRef(s dwarf.Sym, f interface{}) {
panic("should be used only in the compiler")
}
func (c dwctxt) CurrentOffset(s dwarf.Sym) int64 {
panic("should be used only in the compiler")
}