cmd/link: various cleanups using tools

* remove unnecessary explicit types
* remove dead assignments
* remove unused fields
* unindent code using early continues
* remove some unnecessary type conversions
* remove some unused func parameters

Change-Id: I202c67e92940beacbd80fc2dc179f9556dc5d9e5
Reviewed-on: https://go-review.googlesource.com/69118
Run-TryBot: Daniel Martí <mvdan@mvdan.cc>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: David Crawshaw <crawshaw@golang.org>

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

@@ -266,7 +266,7 @@ func reverselist(list **dwarf.DWDie) {
 	curr := *list
 	var prev *dwarf.DWDie
 	for curr != nil {
-		var next *dwarf.DWDie = curr.Link
+		next := curr.Link
 		curr.Link = prev
 		prev = curr
 		curr = next
@@ -1077,7 +1077,6 @@ func writelines(ctxt *Link, syms []*sym.Symbol) ([]*sym.Symbol, []*sym.Symbol) {
 			continue
 		}
 
-		epc = s.Value + s.Size
 		epcs = s
 
 		dsym := ctxt.Syms.Lookup(dwarf.InfoPrefix+s.Name, int(s.Version))

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

@@ -810,7 +810,6 @@ type ElfShdr struct {
 	addralign uint64
 	entsize   uint64
 	shnum     int
-	secsym    *sym.Symbol
 }
 
 /*
@@ -888,7 +887,7 @@ const (
 var (
 	Iself bool
 
-	Nelfsym int = 1
+	Nelfsym = 1
 
 	elf64 bool
 	// Either ".rel" or ".rela" depending on which type of relocation the
@@ -1611,16 +1610,17 @@ func elfphrelro(seg *sym.Segment) {
 
 func elfshname(name string) *ElfShdr {
 	for i := 0; i < nelfstr; i++ {
-		if name == elfstr[i].s {
-			off := elfstr[i].off
-			for i = 0; i < int(ehdr.shnum); i++ {
-				sh := shdr[i]
-				if sh.name == uint32(off) {
-					return sh
-				}
-			}
-			return newElfShdr(int64(off))
+		if name != elfstr[i].s {
+			continue
 		}
+		off := elfstr[i].off
+		for i = 0; i < int(ehdr.shnum); i++ {
+			sh := shdr[i]
+			if sh.name == uint32(off) {
+				return sh
+			}
+		}
+		return newElfShdr(int64(off))
 	}
 	Exitf("cannot find elf name %s", name)
 	return nil

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

@@ -279,7 +279,6 @@ type ElfObj struct {
 	e         binary.ByteOrder
 	sect      []ElfSect
 	nsect     uint
-	shstrtab  string
 	nsymtab   int
 	symtab    *ElfSect
 	symstr    *ElfSect
@@ -426,19 +425,20 @@ func parseArmAttributes(ctxt *Link, e binary.ByteOrder, data []byte) {
 			subsectiondata := sectiondata[sz+4 : subsectionsize]
 			sectiondata = sectiondata[subsectionsize:]
 
-			if subsectiontag == TagFile {
-				attrList := elfAttributeList{data: subsectiondata}
-				for !attrList.done() {
-					attr := attrList.armAttr()
-					if attr.tag == TagABIVFPArgs && attr.ival == 1 {
-						ehdr.flags = 0x5000402 // has entry point, Version5 EABI, hard-float ABI
-					}
-				}
-				if attrList.err != nil {
-					// TODO(dfc) should this be ctxt.Diag ?
-					ctxt.Logf("could not parse .ARM.attributes\n")
+			if subsectiontag != TagFile {
+				continue
+			}
+			attrList := elfAttributeList{data: subsectiondata}
+			for !attrList.done() {
+				attr := attrList.armAttr()
+				if attr.tag == TagABIVFPArgs && attr.ival == 1 {
+					ehdr.flags = 0x5000402 // has entry point, Version5 EABI, hard-float ABI
 				}
 			}
+			if attrList.err != nil {
+				// TODO(dfc) should this be ctxt.Diag ?
+				ctxt.Logf("could not parse .ARM.attributes\n")
+			}
 		}
 	}
 }

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

@@ -574,7 +574,7 @@ func (ctxt *Link) loadlib() {
 	if typeSymbolMangling(ctxt) {
 		*FlagW = true // disable DWARF generation
 		for _, s := range ctxt.Syms.Allsym {
-			newName := typeSymbolMangle(ctxt.Syms, s.Name)
+			newName := typeSymbolMangle(s.Name)
 			if newName != s.Name {
 				ctxt.Syms.Rename(s.Name, newName, int(s.Version))
 			}
@@ -657,7 +657,7 @@ func typeSymbolMangling(ctxt *Link) bool {
 }
 
 // typeSymbolMangle mangles the given symbol name into something shorter.
-func typeSymbolMangle(syms *sym.Symbols, name string) string {
+func typeSymbolMangle(name string) string {
 	if !strings.HasPrefix(name, "type.") {
 		return name
 	}

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

@@ -96,9 +96,9 @@ func (ctxt *Link) FixedFrameSize() int64 {
 	}
 }
 
-func (l *Link) Logf(format string, args ...interface{}) {
-	fmt.Fprintf(l.Bso, format, args...)
-	l.Bso.Flush()
+func (ctxt *Link) Logf(format string, args ...interface{}) {
+	fmt.Fprintf(ctxt.Bso, format, args...)
+	ctxt.Bso.Flush()
 }
 
 func addImports(ctxt *Link, l *sym.Library, pn string) {

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

@@ -180,7 +180,7 @@ var nsortsym int
 // "big enough" header size. The initial header is
 // one page, the non-dynamic library stuff takes
 // up about 1300 bytes; we overestimate that as 2k.
-var loadBudget int = INITIAL_MACHO_HEADR - 2*1024
+var loadBudget = INITIAL_MACHO_HEADR - 2*1024
 
 func getMachoHdr() *MachoHdr {
 	return &machohdr

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

@@ -17,7 +17,7 @@ import (
 
 var realdwarf, linkseg *macho.Segment
 var dwarfstart, linkstart int64
-var dwarfaddr, linkaddr int64
+var dwarfaddr int64
 var linkoffset uint32
 
 const (

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

@@ -73,7 +73,7 @@ func putelfsyment(out *OutBuf, off int, addr int64, size int64, info int, shndx
 	}
 }
 
-var numelfsym int = 1 // 0 is reserved
+var numelfsym = 1 // 0 is reserved
 
 var elfbind int
 
@@ -592,7 +592,7 @@ func (ctxt *Link) symtab() {
 			// pkghashes[i].name
 			addgostring(ctxt, pkghashes, fmt.Sprintf("go.link.pkgname.%d", i), l.Pkg)
 			// pkghashes[i].linktimehash
-			addgostring(ctxt, pkghashes, fmt.Sprintf("go.link.pkglinkhash.%d", i), string(l.Hash))
+			addgostring(ctxt, pkghashes, fmt.Sprintf("go.link.pkglinkhash.%d", i), l.Hash)
 			// pkghashes[i].runtimehash
 			hash := ctxt.Syms.ROLookup("go.link.pkghash."+l.Pkg, 0)
 			pkghashes.AddAddr(ctxt.Arch, hash)