cmd/link: Clean up Pcln struct

Removes unnecessary fields from Pcln.

Change-Id: I175049ca749b510eedaf65162355bc4d7a93315e
Reviewed-on: https://go-review.googlesource.com/21041Reviewed-by: David Crawshaw <crawshaw@golang.org>

src/cmd/link/internal/ld/deadcode.go

@@ -344,7 +344,7 @@ func (d *deadcodepass) flood() {
 		}
 
 		if s.Pcln != nil {
-			for i := 0; i < s.Pcln.Nfuncdata; i++ {
+			for i := range s.Pcln.Funcdata {
 				d.mark(s.Pcln.Funcdata[i], s)
 			}
 		}

src/cmd/link/internal/ld/dwarf.go

@@ -1367,7 +1367,7 @@ func finddebugruntimepath(s *LSym) {
 		return
 	}
 
-	for i := 0; i < s.Pcln.Nfile; i++ {
+	for i := range s.Pcln.File {
 		f := s.Pcln.File[i]
 		if i := strings.Index(f.Name, "runtime/runtime.go"); i >= 0 {
 			gdbscript = f.Name[:i] + "runtime/runtime-gdb.py"

src/cmd/link/internal/ld/link.go

@@ -235,13 +235,9 @@ type Pcln struct {
 	Pcfile      Pcdata
 	Pcline      Pcdata
 	Pcdata      []Pcdata
-	Npcdata     int
 	Funcdata    []*LSym
 	Funcdataoff []int64
-	Nfuncdata   int
 	File        []*LSym
-	Nfile       int
-	Mfile       int
 	Lastfile    *LSym
 	Lastindex   int
 }

src/cmd/link/internal/ld/objfile.go

@@ -282,14 +282,12 @@ overwrite:
 		pc.Pcline.P = rddata(f, buf)
 		n = rdint(f)
 		pc.Pcdata = make([]Pcdata, n)
-		pc.Npcdata = n
 		for i := 0; i < n; i++ {
 			pc.Pcdata[i].P = rddata(f, buf)
 		}
 		n = rdint(f)
 		pc.Funcdata = make([]*LSym, n)
 		pc.Funcdataoff = make([]int64, n)
-		pc.Nfuncdata = n
 		for i := 0; i < n; i++ {
 			pc.Funcdata[i] = rdsym(ctxt, f, pkg)
 		}
@@ -298,7 +296,6 @@ overwrite:
 		}
 		n = rdint(f)
 		pc.File = make([]*LSym, n)
-		pc.Nfile = n
 		for i := 0; i < n; i++ {
 			pc.File[i] = rdsym(ctxt, f, pkg)
 		}

src/cmd/link/internal/ld/pcln.go

@@ -280,8 +280,8 @@ func pclntab() {
 		// fixed size of struct, checked below
 		off = funcstart
 
-		end = funcstart + int32(Thearch.Ptrsize) + 3*4 + 5*4 + int32(pcln.Npcdata)*4 + int32(pcln.Nfuncdata)*int32(Thearch.Ptrsize)
-		if pcln.Nfuncdata > 0 && (end&int32(Thearch.Ptrsize-1) != 0) {
+		end = funcstart + int32(Thearch.Ptrsize) + 3*4 + 5*4 + int32(len(pcln.Pcdata))*4 + int32(len(pcln.Funcdata))*int32(Thearch.Ptrsize)
+		if len(pcln.Funcdata) > 0 && (end&int32(Thearch.Ptrsize-1) != 0) {
 			end += 4
 		}
 		Symgrow(Ctxt, ftab, int64(end))
@@ -321,19 +321,19 @@ func pclntab() {
 
 		off = addpctab(ftab, off, &pcln.Pcfile)
 		off = addpctab(ftab, off, &pcln.Pcline)
-		off = int32(setuint32(Ctxt, ftab, int64(off), uint32(pcln.Npcdata)))
-		off = int32(setuint32(Ctxt, ftab, int64(off), uint32(pcln.Nfuncdata)))
-		for i = 0; i < int32(pcln.Npcdata); i++ {
+		off = int32(setuint32(Ctxt, ftab, int64(off), uint32(len(pcln.Pcdata))))
+		off = int32(setuint32(Ctxt, ftab, int64(off), uint32(len(pcln.Funcdata))))
+		for i = 0; i < int32(len(pcln.Pcdata)); i++ {
 			off = addpctab(ftab, off, &pcln.Pcdata[i])
 		}
 
 		// funcdata, must be pointer-aligned and we're only int32-aligned.
 		// Missing funcdata will be 0 (nil pointer).
-		if pcln.Nfuncdata > 0 {
+		if len(pcln.Funcdata) > 0 {
 			if off&int32(Thearch.Ptrsize-1) != 0 {
 				off += 4
 			}
-			for i = 0; i < int32(pcln.Nfuncdata); i++ {
+			for i = 0; i < int32(len(pcln.Funcdata)); i++ {
 				if pcln.Funcdata[i] == nil {
 					setuintxx(Ctxt, ftab, int64(off)+int64(Thearch.Ptrsize)*int64(i), uint64(pcln.Funcdataoff[i]), int64(Thearch.Ptrsize))
 				} else {
@@ -344,11 +344,11 @@ func pclntab() {
 				}
 			}
 
-			off += int32(pcln.Nfuncdata) * int32(Thearch.Ptrsize)
+			off += int32(len(pcln.Funcdata)) * int32(Thearch.Ptrsize)
 		}
 
 		if off != end {
-			Diag("bad math in functab: funcstart=%d off=%d but end=%d (npcdata=%d nfuncdata=%d ptrsize=%d)", funcstart, off, end, pcln.Npcdata, pcln.Nfuncdata, Thearch.Ptrsize)
+			Diag("bad math in functab: funcstart=%d off=%d but end=%d (npcdata=%d nfuncdata=%d ptrsize=%d)", funcstart, off, end, len(pcln.Pcdata), len(pcln.Funcdata), Thearch.Ptrsize)
 			errorexit()
 		}