[dev.inline] cmd/internal/obj: remove vestiges of LineHist - not used anymore

Change-Id: I9d3fcdd5b002953fa9d2f001bf7a834073443794
Reviewed-on: https://go-review.googlesource.com/34722
TryBot-Result: Gobot Gobot <gobot@golang.org>
Run-TryBot: Robert Griesemer <gri@golang.org>
Reviewed-by: Austin Clements <austin@google.com>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

src/cmd/compile/internal/gc/main.go

@@ -778,7 +778,8 @@ func importfile(f *Val, indent []byte) {
 	defer impf.Close()
 	imp := bufio.NewReader(impf)
 
-	if strings.HasSuffix(file, ".a") {
+	const pkgSuffix = ".a"
+	if strings.HasSuffix(file, pkgSuffix) {
 		if !skiptopkgdef(imp) {
 			yyerror("import %s: not a package file", file)
 			errorexit()
@@ -826,9 +827,9 @@ func importfile(f *Val, indent []byte) {
 		yyerror("cannot import unsafe package %q", importpkg.Path)
 	}
 
-	// assume files move (get installed)
+	// assume files move (get installed) so don't record the full path
-	// so don't record the full path.
+	// (e.g., for file "/Users/foo/go/pkg/darwin_amd64/math.a" record "math.a")
-	linehistpragma(file[len(file)-len(path_)-2:]) // acts as #pragma lib
+	Ctxt.AddImport(file[len(file)-len(path_)-len(pkgSuffix):])
 
 	// In the importfile, if we find:
 	// $$\n  (textual format): not supported anymore

src/cmd/compile/internal/gc/subr.go

@@ -180,14 +180,6 @@ func Fatalf(fmt_ string, args ...interface{}) {
 	errorexit()
 }
 
-// TODO(gri) rename this function
-func linehistpragma(file string) {
-	// if Debug['i'] != 0 {
-	// 	fmt.Printf("pragma %s at line %v\n", file, linestr(lexlineno))
-	// }
-	Ctxt.AddImport(file)
-}
-
 func setlineno(n *Node) src.XPos {
 	lno := lineno
 	if n != nil {

src/cmd/internal/obj/line.go

@@ -6,86 +6,9 @@ package obj
 
 import (
 	"cmd/internal/src"
-	"fmt"
 	"path/filepath"
-	"sort"
-	"strings"
 )
 
-// LineHists are not used anymore. This code is only here for reference during a transition period.
-// TODO(gri) remove this eventually (we still need the LineHist independent functions, though).
-
-// A LineHist records the history of the file input stack, which maps the virtual line number,
-// an incrementing count of lines processed in any input file and typically named lineno,
-// to a stack of file:line pairs showing the path of inclusions that led to that position.
-// The first line directive (//line in Go, #line in assembly) is treated as pushing
-// a new entry on the stack, so that errors can report both the actual and translated
-// line number.
-//
-// In typical use, the virtual lineno begins at 1, and file line numbers also begin at 1,
-// but the only requirements placed upon the numbers by this code are:
-//	- calls to Push, Update, and Pop must be monotonically increasing in lineno
-//	- except as specified by those methods, virtual and file line number increase
-//	  together, so that given (only) calls Push(10, "x.go", 1) and Pop(15),
-//	  virtual line 12 corresponds to x.go line 3.
-type LineHist struct {
-	Top               *LineStack  // current top of stack
-	Ranges            []LineRange // ranges for lookup
-	Dir               string      // directory to qualify relative paths
-	TrimPathPrefix    string      // remove leading TrimPath from recorded file names
-	PrintFilenameOnly bool        // ignore path when pretty-printing a line; internal use only
-	GOROOT            string      // current GOROOT
-}
-
-// A LineStack is an entry in the recorded line history.
-// Although the history at any given line number is a stack,
-// the record for all line processed forms a tree, with common
-// stack prefixes acting as parents.
-type LineStack struct {
-	Parent    *LineStack // parent in inclusion stack
-	Lineno    int        // virtual line number where this entry takes effect
-	File      string     // file name used to open source file, for error messages
-	AbsFile   string     // absolute file name, for pcln tables
-	FileLine  int        // line number in file at Lineno
-	Directive bool
-	Sym       *LSym // for linkgetline - TODO(rsc): remove
-}
-
-func (stk *LineStack) fileLineAt(lineno int) int {
-	return stk.FileLine + lineno - stk.Lineno
-}
-
-// The span of valid linenos in the recorded line history can be broken
-// into a set of ranges, each with a particular stack.
-// A LineRange records one such range.
-type LineRange struct {
-	Start int        // starting lineno
-	Stack *LineStack // top of stack for this range
-}
-
-// startRange starts a new range with the given top of stack.
-func (h *LineHist) startRange(lineno int, top *LineStack) {
-	h.Top = top
-	h.Ranges = append(h.Ranges, LineRange{top.Lineno, top})
-}
-
-// setFile sets stk.File = file and also derives stk.AbsFile.
-func (h *LineHist) setFile(stk *LineStack, file string) {
-	// Note: The exclusion of stk.Directive may be wrong but matches what we've done before.
-	// The check for < avoids putting a path prefix on "<autogenerated>".
-	dir := h.Dir
-	if stk.Directive || strings.HasPrefix(file, "<") {
-		dir = ""
-	}
-
-	stk.AbsFile = AbsFile(dir, file, h.TrimPathPrefix)
-
-	if file == "" {
-		file = "??"
-	}
-	stk.File = file
-}
-
 // AbsFile returns the absolute filename for file in the given directory.
 // It also removes a leading pathPrefix, or else rewrites a leading $GOROOT
 // prefix to the literal "$GOROOT".
@@ -146,161 +69,11 @@ func hasPathPrefix(s string, t string) bool {
 	return i >= len(s) || s[i] == '/' || s[i] == '\\'
 }
 
-// Push records that at that lineno a new file with the given name was pushed onto the input stack.
-func (h *LineHist) Push(lineno int, file string) {
-	stk := &LineStack{
-		Parent:   h.Top,
-		Lineno:   lineno,
-		FileLine: 1,
-	}
-	h.setFile(stk, file)
-	h.startRange(lineno, stk)
-}
-
-// Pop records that at lineno the current file was popped from the input stack.
-func (h *LineHist) Pop(lineno int) {
-	top := h.Top
-	if top == nil {
-		return
-	}
-	if top.Directive && top.Parent != nil { // pop #line level too
-		top = top.Parent
-	}
-	next := top.Parent
-	if next == nil {
-		h.Top = nil
-		h.Ranges = append(h.Ranges, LineRange{lineno, nil})
-		return
-	}
-
-	// Popping included file. Update parent offset to account for
-	// the virtual line number range taken by the included file.
-	// Cannot modify the LineStack directly, or else lookups
-	// for the earlier line numbers will get the wrong answers,
-	// so make a new one.
-	stk := new(LineStack)
-	*stk = *next
-	stk.Lineno = lineno
-	stk.FileLine = next.fileLineAt(top.Lineno)
-	h.startRange(lineno, stk)
-}
-
-// Update records that at lineno the file name and line number were changed using
-// a line directive (//line in Go, #line in assembly).
-func (h *LineHist) Update(lineno int, file string, line int) {
-	top := h.Top
-	if top == nil {
-		return // shouldn't happen
-	}
-	var stk *LineStack
-	if top.Directive {
-		// Update existing entry, except make copy to avoid changing earlier history.
-		stk = new(LineStack)
-		*stk = *top
-	} else {
-		// Push new entry.
-		stk = &LineStack{
-			Parent:    top,
-			Directive: true,
-		}
-	}
-	stk.Lineno = lineno
-	if stk.File != file {
-		h.setFile(stk, file) // only retain string if needed
-	}
-	stk.FileLine = line
-	h.startRange(lineno, stk)
-}
-
 // AddImport adds a package to the list of imported packages.
 func (ctxt *Link) AddImport(pkg string) {
 	ctxt.Imports = append(ctxt.Imports, pkg)
 }
 
-// At returns the input stack in effect at lineno.
-func (h *LineHist) At(lineno int) *LineStack {
-	i := sort.Search(len(h.Ranges), func(i int) bool {
-		return h.Ranges[i].Start > lineno
-	})
-	// Found first entry beyond lineno.
-	if i == 0 {
-		return nil
-	}
-	return h.Ranges[i-1].Stack
-}
-
-// LineString returns a string giving the file and line number
-// corresponding to lineno, for use in error messages.
-func (h *LineHist) LineString(lineno int) string {
-	stk := h.At(lineno)
-	if stk == nil {
-		return "<unknown line number>"
-	}
-
-	filename := stk.File
-	if h.PrintFilenameOnly {
-		filename = filepath.Base(filename)
-	}
-	text := fmt.Sprintf("%s:%d", filename, stk.fileLineAt(lineno))
-	if stk.Directive && stk.Parent != nil {
-		stk = stk.Parent
-		filename = stk.File
-		if h.PrintFilenameOnly {
-			filename = filepath.Base(filename)
-		}
-		text += fmt.Sprintf("[%s:%d]", filename, stk.fileLineAt(lineno))
-	}
-	const showFullStack = false // was used by old C compilers
-	if showFullStack {
-		for stk.Parent != nil {
-			lineno = stk.Lineno - 1
-			stk = stk.Parent
-			text += fmt.Sprintf(" %s:%d", filename, stk.fileLineAt(lineno))
-			if stk.Directive && stk.Parent != nil {
-				stk = stk.Parent
-				text += fmt.Sprintf("[%s:%d]", filename, stk.fileLineAt(lineno))
-			}
-		}
-	}
-	return text
-}
-
-// FileLine returns the file name and line number
-// at the top of the stack for the given lineno.
-func (h *LineHist) FileLine(lineno int) (file string, line int) {
-	stk := h.At(lineno)
-	if stk == nil {
-		return "??", 0
-	}
-	return stk.File, stk.fileLineAt(lineno)
-}
-
-// AbsFileLine returns the absolute file name and line number
-// at the top of the stack for the given lineno.
-func (h *LineHist) AbsFileLine(lineno int) (file string, line int) {
-	stk := h.At(lineno)
-	if stk == nil {
-		return "??", 0
-	}
-	return stk.AbsFile, stk.fileLineAt(lineno)
-}
-
-// This is a simplified copy of linklinefmt above.
-// It doesn't allow printing the full stack, and it returns the file name and line number separately.
-// TODO: Unify with linklinefmt somehow.
-func linkgetline(ctxt *Link, lineno int32) (f *LSym, l int32) {
-	panic("defunct")
-	// stk := ctxt.LineHist.At(int(lineno))
-	// if stk == nil || stk.AbsFile == "" {
-	// 	return Linklookup(ctxt, "??", HistVersion), 0
-	// }
-	// if stk.Sym == nil {
-	// 	stk.Sym = Linklookup(ctxt, stk.AbsFile, HistVersion)
-	// }
-	// return stk.Sym, int32(stk.fileLineAt(int(lineno)))
-}
-
-// This is modified copy of linkgetline to work from src.Pos.
 func linkgetlineFromPos(ctxt *Link, xpos src.XPos) (f *LSym, l int32) {
 	pos := ctxt.PosTable.Pos(xpos)
 	filename := pos.AbsFilename()
@@ -311,11 +84,6 @@ func linkgetlineFromPos(ctxt *Link, xpos src.XPos) (f *LSym, l int32) {
 	return Linklookup(ctxt, filename, HistVersion), int32(pos.RelLine())
 }
 
-func Linkprfile(ctxt *Link, line int) {
-	panic("defunct")
-	// fmt.Printf("%s ", ctxt.LineHist.LineString(line))
-}
-
 func fieldtrack(ctxt *Link, cursym *LSym) {
 	p := cursym.Text
 	if p == nil || p.Link == nil { // handle external functions and ELF section symbols

src/cmd/internal/obj/link.go

@@ -222,8 +222,8 @@ const (
 // The Progs for a given function are arranged in a list linked through the Link field.
 //
 // Each Prog is charged to a specific source line in the debug information,
-// specified by Pos.Line(), an index into the line history (see LineHist).
+// specified by Pos.Line().
-// Every Prog has a Ctxt field that defines various context, including the current LineHist.
+// Every Prog has a Ctxt field that defines its context.
 // Progs should be allocated using ctxt.NewProg(), not new(Prog).
 //
 // The other fields not yet mentioned are for use by the back ends and should

src/cmd/internal/obj/sym.go

@@ -56,10 +56,6 @@ func Linknew(arch *LinkArch) *Link {
 	ctxt.Version = HistVersion
 	ctxt.Pathname = WorkingDir()
 
-	// LineHist is not used anymore
-	// ctxt.LineHist.GOROOT = GOROOT
-	// ctxt.LineHist.Dir = ctxt.Pathname
-
 	ctxt.Headtype.Set(GOOS)
 	if ctxt.Headtype < 0 {
 		log.Fatalf("unknown goos %s", GOOS)