cmd/link: don't record interpreter in flagInterpreter

Keep flagInterpreter unchanged after flag parsing. This lets us replace
flagInterpreterSet with flagInterpreter != "".

Change-Id: Ifd2edbb2ce0011e97276ca18281b8ffbabde1c50
Reviewed-on: https://go-review.googlesource.com/27563
Run-TryBot: Ian Lance Taylor <iant@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>

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

@@ -2205,29 +2205,29 @@ func Asmbelf(ctxt *Link, symo int64) {
 		sh.type_ = SHT_PROGBITS
 		sh.flags = SHF_ALLOC
 		sh.addralign = 1
-		if *flagInterpreter == "" {
+		if interpreter == "" {
 			switch HEADTYPE {
 			case obj.Hlinux:
-				*flagInterpreter = Thearch.Linuxdynld
+				interpreter = Thearch.Linuxdynld
 
 			case obj.Hfreebsd:
-				*flagInterpreter = Thearch.Freebsddynld
+				interpreter = Thearch.Freebsddynld
 
 			case obj.Hnetbsd:
-				*flagInterpreter = Thearch.Netbsddynld
+				interpreter = Thearch.Netbsddynld
 
 			case obj.Hopenbsd:
-				*flagInterpreter = Thearch.Openbsddynld
+				interpreter = Thearch.Openbsddynld
 
 			case obj.Hdragonfly:
-				*flagInterpreter = Thearch.Dragonflydynld
+				interpreter = Thearch.Dragonflydynld
 
 			case obj.Hsolaris:
-				*flagInterpreter = Thearch.Solarisdynld
+				interpreter = Thearch.Solarisdynld
 			}
 		}
 
-		resoff -= int64(elfinterp(sh, uint64(startva), uint64(resoff), *flagInterpreter))
+		resoff -= int64(elfinterp(sh, uint64(startva), uint64(resoff), interpreter))
 
 		ph := newElfPhdr(ctxt)
 		ph.type_ = PT_INTERP

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

@@ -267,14 +267,14 @@ func loadcgo(ctxt *Link, file string, pkg string, p string) {
 				goto err
 			}
 
-			if !flagInterpreterSet {
-				if *flagInterpreter != "" && *flagInterpreter != f[1] {
-					fmt.Fprintf(os.Stderr, "%s: conflict dynlinker: %s and %s\n", os.Args[0], *flagInterpreter, f[1])
+			if *flagInterpreter == "" {
+				if interpreter != "" && interpreter != f[1] {
+					fmt.Fprintf(os.Stderr, "%s: conflict dynlinker: %s and %s\n", os.Args[0], interpreter, f[1])
 					nerrors++
 					return
 				}
 
-				*flagInterpreter = f[1]
+				interpreter = f[1]
 			}
 
 			continue

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

@@ -179,6 +179,7 @@ var (
 	Funcalign       int
 	iscgo           bool
 	elfglobalsymndx int
+	interpreter     string
 
 	debug_s  bool // backup old value of debug['s']
 	HEADR    int32

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

@@ -73,20 +73,18 @@ var (
 	flagExtldflags = flag.String("extldflags", "", "pass `flags` to external linker")
 	flagExtar      = flag.String("extar", "", "archive program for buildmode=c-archive")
 
-	flagA = flag.Bool("a", false, "disassemble output")
-	FlagC = flag.Bool("c", false, "dump call graph")
-	FlagD = flag.Bool("d", false, "disable dynamic executable")
-	flagF = flag.Bool("f", false, "ignore version mismatch")
-	flagG = flag.Bool("g", false, "disable go package data checks")
-	flagH = flag.Bool("h", false, "halt on error")
-	flagN = flag.Bool("n", false, "dump symbol table")
-	FlagS = flag.Bool("s", false, "disable symbol table")
-	flagU = flag.Bool("u", false, "reject unsafe packages")
-	FlagW = flag.Bool("w", false, "disable DWARF generation")
-	Flag8 bool // use 64-bit addresses in symbol table
-
-	flagInterpreter    = flag.String("I", "", "use `linker` as ELF dynamic linker")
-	flagInterpreterSet bool
+	flagA           = flag.Bool("a", false, "disassemble output")
+	FlagC           = flag.Bool("c", false, "dump call graph")
+	FlagD           = flag.Bool("d", false, "disable dynamic executable")
+	flagF           = flag.Bool("f", false, "ignore version mismatch")
+	flagG           = flag.Bool("g", false, "disable go package data checks")
+	flagH           = flag.Bool("h", false, "halt on error")
+	flagN           = flag.Bool("n", false, "dump symbol table")
+	FlagS           = flag.Bool("s", false, "disable symbol table")
+	flagU           = flag.Bool("u", false, "reject unsafe packages")
+	FlagW           = flag.Bool("w", false, "disable DWARF generation")
+	Flag8           bool // use 64-bit addresses in symbol table
+	flagInterpreter = flag.String("I", "", "use `linker` as ELF dynamic linker")
 
 	FlagRound       = flag.Int("R", -1, "set address rounding `quantum`")
 	FlagTextAddr    = flag.Int64("T", -1, "set text segment `address`")
@@ -133,7 +131,6 @@ func Main() {
 	}
 
 	obj.Flagparse(usage)
-	flagInterpreterSet = *flagInterpreter != ""
 
 	startProfile()
 	ctxt.Bso = ctxt.Bso
@@ -159,6 +156,8 @@ func Main() {
 		}
 	}
 
+	interpreter = *flagInterpreter
+
 	libinit(ctxt) // creates outfile
 
 	if HEADTYPE == -1 {