diff --git a/src/cmd/compile/internal/dwarfgen/dwinl.go b/src/cmd/compile/internal/dwarfgen/dwinl.go
index 08544fef6f..92f339d3c6 100644
--- a/src/cmd/compile/internal/dwarfgen/dwinl.go
+++ b/src/cmd/compile/internal/dwarfgen/dwinl.go
@@ -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,
 	}
diff --git a/src/cmd/internal/dwarf/dwarf.go b/src/cmd/internal/dwarf/dwarf.go
index 86bc9e6823..c48b576fa0 100644
--- a/src/cmd/internal/dwarf/dwarf.go
+++ b/src/cmd/internal/dwarf/dwarf.go
@@ -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 {
diff --git a/src/cmd/internal/obj/dwarf.go b/src/cmd/internal/obj/dwarf.go
index 825f0133f1..f5caa08f0a 100644
--- a/src/cmd/internal/obj/dwarf.go
+++ b/src/cmd/internal/obj/dwarf.go
@@ -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,
diff --git a/src/cmd/internal/obj/line.go b/src/cmd/internal/obj/line.go
index 20f03d9853..988640f6a4 100644
--- a/src/cmd/internal/obj/line.go
+++ b/src/cmd/internal/obj/line.go
@@ -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())
 }
diff --git a/src/cmd/internal/obj/line_test.go b/src/cmd/internal/obj/line_test.go
index d3bb4e2639..de7ef1a22e 100644
--- a/src/cmd/internal/obj/line_test.go
+++ b/src/cmd/internal/obj/line_test.go
@@ -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)
 		}
 	}
diff --git a/src/cmd/internal/obj/plist.go b/src/cmd/internal/obj/plist.go
index cd6e2313ad..9cf6a20bdb 100644
--- a/src/cmd/internal/obj/plist.go
+++ b/src/cmd/internal/obj/plist.go
@@ -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)
diff --git a/src/cmd/internal/obj/sym.go b/src/cmd/internal/obj/sym.go
index 63d7d22e33..f27d4ef4fc 100644
--- a/src/cmd/internal/obj/sym.go
+++ b/src/cmd/internal/obj/sym.go
@@ -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}
diff --git a/src/cmd/internal/src/pos.go b/src/cmd/internal/src/pos.go
index 6f1c7dddbc..4d71c8190a 100644
--- a/src/cmd/internal/src/pos.go
+++ b/src/cmd/internal/src/pos.go
@@ -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.
diff --git a/src/cmd/internal/src/xpos.go b/src/cmd/internal/src/xpos.go
index 867d0ab069..a74505997d 100644
--- a/src/cmd/internal/src/xpos.go
+++ b/src/cmd/internal/src/xpos.go
@@ -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
diff --git a/src/cmd/internal/src/xpos_test.go b/src/cmd/internal/src/xpos_test.go
index a17ba63d2a..f76de9dbc2 100644
--- a/src/cmd/internal/src/xpos_test.go
+++ b/src/cmd/internal/src/xpos_test.go
@@ -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
diff --git a/src/cmd/link/internal/ld/dwarf.go b/src/cmd/link/internal/ld/dwarf.go
index 23285de2e1..36e11cc0d2 100644
--- a/src/cmd/link/internal/ld/dwarf.go
+++ b/src/cmd/link/internal/ld/dwarf.go
@@ -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")
 }