cmd/link: added support for mips64{,le}

Only internal linking without cgo is supported for now.

Change-Id: Ie6074a8ff3ec13605b72028f2d60758034f87185
Reviewed-on: https://go-review.googlesource.com/14444
Reviewed-by: Minux Ma <minux@golang.org>

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

@@ -68,3 +68,21 @@ var Linkppc64le = LinkArch{
 	Ptrsize:   8,
 	Regsize:   8,
 }
+
+var Linkmips64 = LinkArch{
+	ByteOrder: binary.BigEndian,
+	Name:      "mips64",
+	Thechar:   '0',
+	Minlc:     4,
+	Ptrsize:   8,
+	Regsize:   8,
+}
+
+var Linkmips64le = LinkArch{
+	ByteOrder: binary.LittleEndian,
+	Name:      "mips64le",
+	Thechar:   '0',
+	Minlc:     4,
+	Ptrsize:   8,
+	Regsize:   8,
+}

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

@@ -2309,7 +2309,7 @@ func dwarfaddshstrings(shstrtab *LSym) {
 	elfstrdbg[ElfStrGDBScripts] = Addstring(shstrtab, ".debug_gdb_scripts")
 	if Linkmode == LinkExternal {
 		switch Thearch.Thechar {
-		case '6', '7', '9':
+		case '0', '6', '7', '9':
 			elfstrdbg[ElfStrRelDebugInfo] = Addstring(shstrtab, ".rela.debug_info")
 			elfstrdbg[ElfStrRelDebugAranges] = Addstring(shstrtab, ".rela.debug_aranges")
 			elfstrdbg[ElfStrRelDebugLine] = Addstring(shstrtab, ".rela.debug_line")
@@ -2362,7 +2362,7 @@ func dwarfaddelfsectionsyms() {
 func dwarfaddelfrelocheader(elfstr int, shdata *ElfShdr, off int64, size int64) {
 	sh := newElfShdr(elfstrdbg[elfstr])
 	switch Thearch.Thechar {
-	case '6', '7', '9':
+	case '0', '6', '7', '9':
 		sh.type_ = SHT_RELA
 	default:
 		sh.type_ = SHT_REL

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

@@ -804,7 +804,10 @@ func Elfinit() {
 		}
 		fallthrough
 
-	case '6', '7':
+	case '0', '6', '7':
+		if Thearch.Thechar == '0' {
+			ehdr.flags = 0x20000000 /* MIPS 3 */
+		}
 		elf64 = true
 
 		ehdr.phoff = ELF64HDRSIZE      /* Must be be ELF64HDRSIZE: first PHdr must follow ELF header */
@@ -1434,7 +1437,7 @@ func elfdynhash() {
 	}
 
 	switch Thearch.Thechar {
-	case '6', '7', '9':
+	case '0', '6', '7', '9':
 		sy := Linklookup(Ctxt, ".rela.plt", 0)
 		if sy.Size > 0 {
 			Elfwritedynent(s, DT_PLTREL, DT_RELA)
@@ -1574,7 +1577,7 @@ func elfshreloc(sect *Section) *ElfShdr {
 	var prefix string
 	var typ int
 	switch Thearch.Thechar {
-	case '6', '7', '9':
+	case '0', '6', '7', '9':
 		prefix = ".rela"
 		typ = SHT_RELA
 	default:
@@ -1747,7 +1750,7 @@ func doelf() {
 		Debug['d'] = 1
 
 		switch Thearch.Thechar {
-		case '6', '7', '9':
+		case '0', '6', '7', '9':
 			Addstring(shstrtab, ".rela.text")
 			Addstring(shstrtab, ".rela.rodata")
 			Addstring(shstrtab, ".rela"+relro_prefix+".typelink")
@@ -1793,7 +1796,7 @@ func doelf() {
 	if hasinitarr {
 		Addstring(shstrtab, ".init_array")
 		switch Thearch.Thechar {
-		case '6', '7', '9':
+		case '0', '6', '7', '9':
 			Addstring(shstrtab, ".rela.init_array")
 		default:
 			Addstring(shstrtab, ".rel.init_array")
@@ -1820,7 +1823,7 @@ func doelf() {
 		Addstring(shstrtab, ".dynsym")
 		Addstring(shstrtab, ".dynstr")
 		switch Thearch.Thechar {
-		case '6', '7', '9':
+		case '0', '6', '7', '9':
 			Addstring(shstrtab, ".rela")
 			Addstring(shstrtab, ".rela.plt")
 		default:
@@ -1838,7 +1841,7 @@ func doelf() {
 		s.Type = obj.SELFROSECT
 		s.Reachable = true
 		switch Thearch.Thechar {
-		case '6', '7', '9':
+		case '0', '6', '7', '9':
 			s.Size += ELF64SYMSIZE
 		default:
 			s.Size += ELF32SYMSIZE
@@ -1856,7 +1859,7 @@ func doelf() {
 
 		/* relocation table */
 		switch Thearch.Thechar {
-		case '6', '7', '9':
+		case '0', '6', '7', '9':
 			s = Linklookup(Ctxt, ".rela", 0)
 		default:
 			s = Linklookup(Ctxt, ".rel", 0)
@@ -1901,7 +1904,7 @@ func doelf() {
 		Thearch.Elfsetupplt()
 
 		switch Thearch.Thechar {
-		case '6', '7', '9':
+		case '0', '6', '7', '9':
 			s = Linklookup(Ctxt, ".rela.plt", 0)
 		default:
 			s = Linklookup(Ctxt, ".rel.plt", 0)
@@ -1930,7 +1933,7 @@ func doelf() {
 
 		elfwritedynentsym(s, DT_SYMTAB, Linklookup(Ctxt, ".dynsym", 0))
 		switch Thearch.Thechar {
-		case '6', '7', '9':
+		case '0', '6', '7', '9':
 			Elfwritedynent(s, DT_SYMENT, ELF64SYMSIZE)
 		default:
 			Elfwritedynent(s, DT_SYMENT, ELF32SYMSIZE)
@@ -1938,7 +1941,7 @@ func doelf() {
 		elfwritedynentsym(s, DT_STRTAB, Linklookup(Ctxt, ".dynstr", 0))
 		elfwritedynentsymsize(s, DT_STRSZ, Linklookup(Ctxt, ".dynstr", 0))
 		switch Thearch.Thechar {
-		case '6', '7', '9':
+		case '0', '6', '7', '9':
 			elfwritedynentsym(s, DT_RELA, Linklookup(Ctxt, ".rela", 0))
 			elfwritedynentsymsize(s, DT_RELASZ, Linklookup(Ctxt, ".rela", 0))
 			Elfwritedynent(s, DT_RELAENT, ELF64RELASIZE)
@@ -2037,6 +2040,8 @@ func Asmbelf(symo int64) {
 	switch Thearch.Thechar {
 	default:
 		Exitf("unknown architecture in asmbelf: %v", Thearch.Thechar)
+	case '0':
+		eh.machine = EM_MIPS
 	case '5':
 		eh.machine = EM_ARM
 	case '6':

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

@@ -551,6 +551,12 @@ func ldelf(f *obj.Biobuf, pkg string, length int64, pn string) {
 		Diag("%s: elf %s unimplemented", pn, Thestring)
 		return
 
+	case '0':
+		if elfobj.machine != ElfMachMips || hdr.Ident[4] != ElfClass64 {
+			Diag("%s: elf object but not mips64", pn)
+			return
+		}
+
 	case '5':
 		if e != binary.LittleEndian || elfobj.machine != ElfMachArm || hdr.Ident[4] != ElfClass32 {
 			Diag("%s: elf object but not arm", pn)

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

@@ -1706,7 +1706,7 @@ func stkcheck(up *Chain, depth int) int {
 			r = &s.R[ri]
 			switch r.Type {
 			// Direct call.
-			case obj.R_CALL, obj.R_CALLARM, obj.R_CALLARM64, obj.R_CALLPOWER:
+			case obj.R_CALL, obj.R_CALLARM, obj.R_CALLARM64, obj.R_CALLPOWER, obj.R_CALLMIPS:
 				ch.limit = int(int32(limit) - pcsp.value - int32(callsize()))
 				ch.sym = r.Sym
 				if stkcheck(&ch, depth+1) < 0 {
@@ -2028,7 +2028,7 @@ func callgraph() {
 			if r.Sym == nil {
 				continue
 			}
-			if (r.Type == obj.R_CALL || r.Type == obj.R_CALLARM || r.Type == obj.R_CALLPOWER) && r.Sym.Type == obj.STEXT {
+			if (r.Type == obj.R_CALL || r.Type == obj.R_CALLARM || r.Type == obj.R_CALLPOWER || r.Type == obj.R_CALLMIPS) && r.Sym.Type == obj.STEXT {
 				fmt.Fprintf(&Bso, "%s calls %s\n", s.Name, r.Sym.Name)
 			}
 		}

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

@@ -67,7 +67,7 @@ func putelfstr(s string) int {
 
 func putelfsyment(off int, addr int64, size int64, info int, shndx int, other int) {
 	switch Thearch.Thechar {
-	case '6', '7', '9':
+	case '0', '6', '7', '9':
 		Thearch.Lput(uint32(off))
 		Cput(uint8(info))
 		Cput(uint8(other))

src/cmd/link/internal/mips64/asm.go

@@ -0,0 +1,248 @@
+// Inferno utils/5l/asm.c
+// http://code.google.com/p/inferno-os/source/browse/utils/5l/asm.c
+//
+//	Copyright © 1994-1999 Lucent Technologies Inc.  All rights reserved.
+//	Portions Copyright © 1995-1997 C H Forsyth (forsyth@terzarima.net)
+//	Portions Copyright © 1997-1999 Vita Nuova Limited
+//	Portions Copyright © 2000-2007 Vita Nuova Holdings Limited (www.vitanuova.com)
+//	Portions Copyright © 2004,2006 Bruce Ellis
+//	Portions Copyright © 2005-2007 C H Forsyth (forsyth@terzarima.net)
+//	Revisions Copyright © 2000-2007 Lucent Technologies Inc. and others
+//	Portions Copyright © 2009 The Go Authors.  All rights reserved.
+//
+// Permission is hereby granted, free of charge, to any person obtaining a copy
+// of this software and associated documentation files (the "Software"), to deal
+// in the Software without restriction, including without limitation the rights
+// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+// copies of the Software, and to permit persons to whom the Software is
+// furnished to do so, subject to the following conditions:
+//
+// The above copyright notice and this permission notice shall be included in
+// all copies or substantial portions of the Software.
+//
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL THE
+// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+// THE SOFTWARE.
+
+package mips64
+
+import (
+	"cmd/internal/obj"
+	"cmd/link/internal/ld"
+	"encoding/binary"
+	"fmt"
+	"log"
+)
+
+func gentext() {}
+
+func adddynrela(rel *ld.LSym, s *ld.LSym, r *ld.Reloc) {
+	log.Fatalf("adddynrela not implemented")
+}
+
+func adddynrel(s *ld.LSym, r *ld.Reloc) {
+	log.Fatalf("adddynrel not implemented")
+}
+
+func elfreloc1(r *ld.Reloc, sectoff int64) int {
+	return -1
+}
+
+func elfsetupplt() {
+	return
+}
+
+func machoreloc1(r *ld.Reloc, sectoff int64) int {
+	return -1
+}
+
+func archreloc(r *ld.Reloc, s *ld.LSym, val *int64) int {
+	if ld.Linkmode == ld.LinkExternal {
+		return -1
+	}
+
+	switch r.Type {
+	case obj.R_CONST:
+		*val = r.Add
+		return 0
+
+	case obj.R_GOTOFF:
+		*val = ld.Symaddr(r.Sym) + r.Add - ld.Symaddr(ld.Linklookup(ld.Ctxt, ".got", 0))
+		return 0
+
+	case obj.R_ADDRMIPS:
+		t := ld.Symaddr(r.Sym) + r.Add
+		if t >= 1<<32 || t < -1<<32 {
+			ld.Diag("program too large, address relocation = %v", t)
+		}
+
+		// the first instruction is always at the lower address, this is endian neutral;
+		// but note that o1 and o2 should still use the target endian.
+		o1 := ld.Thelinkarch.ByteOrder.Uint32(s.P[r.Off:])
+		o2 := ld.Thelinkarch.ByteOrder.Uint32(s.P[r.Off+4:])
+		o1 = o1&0xffff0000 | uint32(t>>16)&0xffff
+		o2 = o2&0xffff0000 | uint32(t)&0xffff
+
+		// when laid out, the instruction order must always be o1, o2.
+		if ld.Ctxt.Arch.ByteOrder == binary.BigEndian {
+			*val = int64(o1)<<32 | int64(o2)
+		} else {
+			*val = int64(o2)<<32 | int64(o1)
+		}
+		return 0
+
+	case obj.R_CALLMIPS,
+		obj.R_JMPMIPS:
+		// Low 26 bits = (S + A) >> 2
+		t := ld.Symaddr(r.Sym) + r.Add
+		o1 := ld.Thelinkarch.ByteOrder.Uint32(s.P[r.Off:])
+		*val = int64(o1&0xfc000000 | uint32(t>>2)&^0xfc000000)
+		return 0
+	}
+
+	return -1
+}
+
+func archrelocvariant(r *ld.Reloc, s *ld.LSym, t int64) int64 {
+	return -1
+}
+
+func asmb() {
+	if ld.Debug['v'] != 0 {
+		fmt.Fprintf(&ld.Bso, "%5.2f asmb\n", obj.Cputime())
+	}
+	ld.Bso.Flush()
+
+	if ld.Iself {
+		ld.Asmbelfsetup()
+	}
+
+	sect := ld.Segtext.Sect
+	ld.Cseek(int64(sect.Vaddr - ld.Segtext.Vaddr + ld.Segtext.Fileoff))
+	ld.Codeblk(int64(sect.Vaddr), int64(sect.Length))
+	for sect = sect.Next; sect != nil; sect = sect.Next {
+		ld.Cseek(int64(sect.Vaddr - ld.Segtext.Vaddr + ld.Segtext.Fileoff))
+		ld.Datblk(int64(sect.Vaddr), int64(sect.Length))
+	}
+
+	if ld.Segrodata.Filelen > 0 {
+		if ld.Debug['v'] != 0 {
+			fmt.Fprintf(&ld.Bso, "%5.2f rodatblk\n", obj.Cputime())
+		}
+		ld.Bso.Flush()
+
+		ld.Cseek(int64(ld.Segrodata.Fileoff))
+		ld.Datblk(int64(ld.Segrodata.Vaddr), int64(ld.Segrodata.Filelen))
+	}
+
+	if ld.Debug['v'] != 0 {
+		fmt.Fprintf(&ld.Bso, "%5.2f datblk\n", obj.Cputime())
+	}
+	ld.Bso.Flush()
+
+	ld.Cseek(int64(ld.Segdata.Fileoff))
+	ld.Datblk(int64(ld.Segdata.Vaddr), int64(ld.Segdata.Filelen))
+
+	/* output symbol table */
+	ld.Symsize = 0
+
+	ld.Lcsize = 0
+	symo := uint32(0)
+	if ld.Debug['s'] == 0 {
+		// TODO: rationalize
+		if ld.Debug['v'] != 0 {
+			fmt.Fprintf(&ld.Bso, "%5.2f sym\n", obj.Cputime())
+		}
+		ld.Bso.Flush()
+		switch ld.HEADTYPE {
+		default:
+			if ld.Iself {
+				symo = uint32(ld.Segdata.Fileoff + ld.Segdata.Filelen)
+				symo = uint32(ld.Rnd(int64(symo), int64(ld.INITRND)))
+			}
+
+		case obj.Hplan9:
+			symo = uint32(ld.Segdata.Fileoff + ld.Segdata.Filelen)
+		}
+
+		ld.Cseek(int64(symo))
+		switch ld.HEADTYPE {
+		default:
+			if ld.Iself {
+				if ld.Debug['v'] != 0 {
+					fmt.Fprintf(&ld.Bso, "%5.2f elfsym\n", obj.Cputime())
+				}
+				ld.Asmelfsym()
+				ld.Cflush()
+				ld.Cwrite(ld.Elfstrdat)
+
+				if ld.Debug['v'] != 0 {
+					fmt.Fprintf(&ld.Bso, "%5.2f dwarf\n", obj.Cputime())
+				}
+				ld.Dwarfemitdebugsections()
+
+				if ld.Linkmode == ld.LinkExternal {
+					ld.Elfemitreloc()
+				}
+			}
+
+		case obj.Hplan9:
+			ld.Asmplan9sym()
+			ld.Cflush()
+
+			sym := ld.Linklookup(ld.Ctxt, "pclntab", 0)
+			if sym != nil {
+				ld.Lcsize = int32(len(sym.P))
+				for i := 0; int32(i) < ld.Lcsize; i++ {
+					ld.Cput(uint8(sym.P[i]))
+				}
+
+				ld.Cflush()
+			}
+		}
+	}
+
+	ld.Ctxt.Cursym = nil
+	if ld.Debug['v'] != 0 {
+		fmt.Fprintf(&ld.Bso, "%5.2f header\n", obj.Cputime())
+	}
+	ld.Bso.Flush()
+	ld.Cseek(0)
+	switch ld.HEADTYPE {
+	default:
+	case obj.Hplan9: /* plan 9 */
+		magic := uint32(4*18*18 + 7)
+		if ld.Thestring == "mips64le" {
+			magic = uint32(4*26*26 + 7)
+		}
+		ld.Thearch.Lput(uint32(magic))              /* magic */
+		ld.Thearch.Lput(uint32(ld.Segtext.Filelen)) /* sizes */
+		ld.Thearch.Lput(uint32(ld.Segdata.Filelen))
+		ld.Thearch.Lput(uint32(ld.Segdata.Length - ld.Segdata.Filelen))
+		ld.Thearch.Lput(uint32(ld.Symsize))      /* nsyms */
+		ld.Thearch.Lput(uint32(ld.Entryvalue())) /* va of entry */
+		ld.Thearch.Lput(0)
+		ld.Thearch.Lput(uint32(ld.Lcsize))
+
+	case obj.Hlinux,
+		obj.Hfreebsd,
+		obj.Hnetbsd,
+		obj.Hopenbsd,
+		obj.Hnacl:
+		ld.Asmbelf(int64(symo))
+	}
+
+	ld.Cflush()
+	if ld.Debug['c'] != 0 {
+		fmt.Printf("textsize=%d\n", ld.Segtext.Filelen)
+		fmt.Printf("datsize=%d\n", ld.Segdata.Filelen)
+		fmt.Printf("bsssize=%d\n", ld.Segdata.Length-ld.Segdata.Filelen)
+		fmt.Printf("symsize=%d\n", ld.Symsize)
+		fmt.Printf("lcsize=%d\n", ld.Lcsize)
+		fmt.Printf("total=%d\n", ld.Segtext.Filelen+ld.Segdata.Length+uint64(ld.Symsize)+uint64(ld.Lcsize))
+	}
+}

src/cmd/link/internal/mips64/l.go

@@ -0,0 +1,75 @@
+// Inferno utils/5l/asm.c
+// http://code.google.com/p/inferno-os/source/browse/utils/5l/asm.c
+//
+//	Copyright © 1994-1999 Lucent Technologies Inc.  All rights reserved.
+//	Portions Copyright © 1995-1997 C H Forsyth (forsyth@terzarima.net)
+//	Portions Copyright © 1997-1999 Vita Nuova Limited
+//	Portions Copyright © 2000-2007 Vita Nuova Holdings Limited (www.vitanuova.com)
+//	Portions Copyright © 2004,2006 Bruce Ellis
+//	Portions Copyright © 2005-2007 C H Forsyth (forsyth@terzarima.net)
+//	Revisions Copyright © 2000-2007 Lucent Technologies Inc. and others
+//	Portions Copyright © 2009 The Go Authors.  All rights reserved.
+//
+// Permission is hereby granted, free of charge, to any person obtaining a copy
+// of this software and associated documentation files (the "Software"), to deal
+// in the Software without restriction, including without limitation the rights
+// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+// copies of the Software, and to permit persons to whom the Software is
+// furnished to do so, subject to the following conditions:
+//
+// The above copyright notice and this permission notice shall be included in
+// all copies or substantial portions of the Software.
+//
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL THE
+// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+// THE SOFTWARE.
+
+package mips64
+
+// Writing object files.
+
+// cmd/9l/l.h from Vita Nuova.
+//
+//	Copyright © 1994-1999 Lucent Technologies Inc.  All rights reserved.
+//	Portions Copyright © 1995-1997 C H Forsyth (forsyth@terzarima.net)
+//	Portions Copyright © 1997-1999 Vita Nuova Limited
+//	Portions Copyright © 2000-2008 Vita Nuova Holdings Limited (www.vitanuova.com)
+//	Portions Copyright © 2004,2006 Bruce Ellis
+//	Portions Copyright © 2005-2007 C H Forsyth (forsyth@terzarima.net)
+//	Revisions Copyright © 2000-2008 Lucent Technologies Inc. and others
+//	Portions Copyright © 2009 The Go Authors.  All rights reserved.
+//
+// Permission is hereby granted, free of charge, to any person obtaining a copy
+// of this software and associated documentation files (the "Software"), to deal
+// in the Software without restriction, including without limitation the rights
+// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+// copies of the Software, and to permit persons to whom the Software is
+// furnished to do so, subject to the following conditions:
+//
+// The above copyright notice and this permission notice shall be included in
+// all copies or substantial portions of the Software.
+//
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL THE
+// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+// THE SOFTWARE.
+
+const (
+	thechar   = '0'
+	MaxAlign  = 32 // max data alignment
+	FuncAlign = 8
+	MINLC     = 4
+)
+
+/* Used by ../internal/ld/dwarf.go */
+const (
+	DWARFREGSP = 29
+	DWARFREGLR = 31
+)

src/cmd/link/internal/mips64/obj.go

@@ -0,0 +1,158 @@
+// Inferno utils/5l/obj.c
+// http://code.google.com/p/inferno-os/source/browse/utils/5l/obj.c
+//
+//	Copyright © 1994-1999 Lucent Technologies Inc.  All rights reserved.
+//	Portions Copyright © 1995-1997 C H Forsyth (forsyth@terzarima.net)
+//	Portions Copyright © 1997-1999 Vita Nuova Limited
+//	Portions Copyright © 2000-2007 Vita Nuova Holdings Limited (www.vitanuova.com)
+//	Portions Copyright © 2004,2006 Bruce Ellis
+//	Portions Copyright © 2005-2007 C H Forsyth (forsyth@terzarima.net)
+//	Revisions Copyright © 2000-2007 Lucent Technologies Inc. and others
+//	Portions Copyright © 2009 The Go Authors.  All rights reserved.
+//
+// Permission is hereby granted, free of charge, to any person obtaining a copy
+// of this software and associated documentation files (the "Software"), to deal
+// in the Software without restriction, including without limitation the rights
+// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+// copies of the Software, and to permit persons to whom the Software is
+// furnished to do so, subject to the following conditions:
+//
+// The above copyright notice and this permission notice shall be included in
+// all copies or substantial portions of the Software.
+//
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL THE
+// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+// THE SOFTWARE.
+
+package mips64
+
+import (
+	"cmd/internal/obj"
+	"cmd/link/internal/ld"
+	"fmt"
+	"log"
+)
+
+// Reading object files.
+
+func Main() {
+	linkarchinit()
+	ld.Ldmain()
+}
+
+func linkarchinit() {
+	ld.Thestring = obj.Getgoarch()
+	if ld.Thestring == "mips64le" {
+		ld.Thelinkarch = &ld.Linkmips64le
+	} else {
+		ld.Thelinkarch = &ld.Linkmips64
+	}
+
+	ld.Thearch.Thechar = thechar
+	ld.Thearch.Ptrsize = ld.Thelinkarch.Ptrsize
+	ld.Thearch.Intsize = ld.Thelinkarch.Ptrsize
+	ld.Thearch.Regsize = ld.Thelinkarch.Regsize
+	ld.Thearch.Funcalign = FuncAlign
+	ld.Thearch.Maxalign = MaxAlign
+	ld.Thearch.Minlc = MINLC
+	ld.Thearch.Dwarfregsp = DWARFREGSP
+	ld.Thearch.Dwarfreglr = DWARFREGLR
+
+	ld.Thearch.Adddynrel = adddynrel
+	ld.Thearch.Archinit = archinit
+	ld.Thearch.Archreloc = archreloc
+	ld.Thearch.Archrelocvariant = archrelocvariant
+	ld.Thearch.Asmb = asmb
+	ld.Thearch.Elfreloc1 = elfreloc1
+	ld.Thearch.Elfsetupplt = elfsetupplt
+	ld.Thearch.Gentext = gentext
+	ld.Thearch.Machoreloc1 = machoreloc1
+	if ld.Thelinkarch == &ld.Linkmips64le {
+		ld.Thearch.Lput = ld.Lputl
+		ld.Thearch.Wput = ld.Wputl
+		ld.Thearch.Vput = ld.Vputl
+	} else {
+		ld.Thearch.Lput = ld.Lputb
+		ld.Thearch.Wput = ld.Wputb
+		ld.Thearch.Vput = ld.Vputb
+	}
+
+	ld.Thearch.Linuxdynld = "/lib64/ld64.so.1"
+
+	ld.Thearch.Freebsddynld = "XXX"
+	ld.Thearch.Openbsddynld = "XXX"
+	ld.Thearch.Netbsddynld = "XXX"
+	ld.Thearch.Dragonflydynld = "XXX"
+	ld.Thearch.Solarisdynld = "XXX"
+}
+
+func archinit() {
+	// getgoextlinkenabled is based on GO_EXTLINK_ENABLED when
+	// Go was built; see ../../make.bash.
+	if ld.Linkmode == ld.LinkAuto && obj.Getgoextlinkenabled() == "0" {
+		ld.Linkmode = ld.LinkInternal
+	}
+
+	switch ld.HEADTYPE {
+	default:
+		if ld.Linkmode == ld.LinkAuto {
+			ld.Linkmode = ld.LinkInternal
+		}
+		if ld.Linkmode == ld.LinkExternal && obj.Getgoextlinkenabled() != "1" {
+			log.Fatalf("cannot use -linkmode=external with -H %s", ld.Headstr(int(ld.HEADTYPE)))
+		}
+	}
+
+	switch ld.HEADTYPE {
+	default:
+		ld.Exitf("unknown -H option: %v", ld.HEADTYPE)
+
+	case obj.Hplan9: /* plan 9 */
+		ld.HEADR = 32
+
+		if ld.INITTEXT == -1 {
+			ld.INITTEXT = 16*1024 + int64(ld.HEADR)
+		}
+		if ld.INITDAT == -1 {
+			ld.INITDAT = 0
+		}
+		if ld.INITRND == -1 {
+			ld.INITRND = 16 * 1024
+		}
+
+	case obj.Hlinux: /* mips64 elf */
+		ld.Elfinit()
+		ld.HEADR = ld.ELFRESERVE
+		if ld.INITTEXT == -1 {
+			ld.INITTEXT = 0x10000 + int64(ld.HEADR)
+		}
+		if ld.INITDAT == -1 {
+			ld.INITDAT = 0
+		}
+		if ld.INITRND == -1 {
+			ld.INITRND = 0x10000
+		}
+
+	case obj.Hnacl:
+		ld.Elfinit()
+		ld.HEADR = 0x10000
+		ld.Funcalign = 16
+		if ld.INITTEXT == -1 {
+			ld.INITTEXT = 0x20000
+		}
+		if ld.INITDAT == -1 {
+			ld.INITDAT = 0
+		}
+		if ld.INITRND == -1 {
+			ld.INITRND = 0x10000
+		}
+	}
+
+	if ld.INITDAT != 0 && ld.INITRND != 0 {
+		fmt.Printf("warning: -D0x%x is ignored because of -R0x%x\n", uint64(ld.INITDAT), uint32(ld.INITRND))
+	}
+}

src/cmd/link/main.go

@@ -9,6 +9,7 @@ import (
 	"cmd/link/internal/amd64"
 	"cmd/link/internal/arm"
 	"cmd/link/internal/arm64"
+	"cmd/link/internal/mips64"
 	"cmd/link/internal/ppc64"
 	"cmd/link/internal/x86"
 	"fmt"
@@ -28,6 +29,8 @@ func main() {
 		arm.Main()
 	case "arm64":
 		arm64.Main()
+	case "mips64", "mips64le":
+		mips64.Main()
 	case "ppc64", "ppc64le":
 		ppc64.Main()
 	}