Example #1
0
func reloc() {
	if Debug['v'] != 0 {
		fmt.Fprintf(&Bso, "%5.2f reloc\n", obj.Cputime())
	}
	Bflush(&Bso)

	for s := Ctxt.Textp; s != nil; s = s.Next {
		relocsym(s)
	}
	for s := datap; s != nil; s = s.Next {
		relocsym(s)
	}
}
Example #2
0
func dynreloc() {
	// -d suppresses dynamic loader format, so we may as well not
	// compute these sections or mark their symbols as reachable.
	if Debug['d'] != 0 && HEADTYPE != Hwindows {
		return
	}
	if Debug['v'] != 0 {
		fmt.Fprintf(&Bso, "%5.2f reloc\n", obj.Cputime())
	}
	Bflush(&Bso)

	for s := Ctxt.Textp; s != nil; s = s.Next {
		dynrelocsym(s)
	}
	for s := datap; s != nil; s = s.Next {
		dynrelocsym(s)
	}
	if Iself {
		elfdynhash()
	}
}
Example #3
0
File: pobj.go Project: korli/go
func Ldmain() {
	Ctxt = linknew(Thelinkarch)
	Ctxt.Thechar = int32(Thearch.Thechar)
	Ctxt.Thestring = Thestring
	Ctxt.Diag = Diag
	Ctxt.Bso = &Bso

	Bso = *obj.Binitw(os.Stdout)
	Debug = [128]int{}
	nerrors = 0
	outfile = ""
	HEADTYPE = -1
	INITTEXT = -1
	INITDAT = -1
	INITRND = -1
	INITENTRY = ""
	Linkmode = LinkAuto

	// For testing behavior of go command when tools crash silently.
	// Undocumented, not in standard flag parser to avoid
	// exposing in usage message.
	for _, arg := range os.Args {
		if arg == "-crash_for_testing" {
			os.Exit(2)
		}
	}

	if Thearch.Thechar == '6' && obj.Getgoos() == "plan9" {
		obj.Flagcount("8", "use 64-bit addresses in symbol table", &Debug['8'])
	}
	obj.Flagfn1("B", "add an ELF NT_GNU_BUILD_ID `note` when using ELF", addbuildinfo)
	obj.Flagcount("C", "check Go calls to C code", &Debug['C'])
	obj.Flagint64("D", "set data segment `address`", &INITDAT)
	obj.Flagstr("E", "set `entry` symbol name", &INITENTRY)
	obj.Flagfn1("I", "use `linker` as ELF dynamic linker", setinterp)
	obj.Flagfn1("L", "add specified `directory` to library path", Lflag)
	obj.Flagfn1("H", "set header `type`", setheadtype)
	obj.Flagint32("R", "set address rounding `quantum`", &INITRND)
	obj.Flagint64("T", "set text segment `address`", &INITTEXT)
	obj.Flagfn0("V", "print version and exit", doversion)
	obj.Flagcount("W", "disassemble input", &Debug['W'])
	obj.Flagfn1("X", "add string value `definition` of the form importpath.name=value", addstrdata1)
	obj.Flagcount("a", "disassemble output", &Debug['a'])
	obj.Flagstr("buildid", "record `id` as Go toolchain build id", &buildid)
	flag.Var(&Buildmode, "buildmode", "set build `mode`")
	obj.Flagcount("c", "dump call graph", &Debug['c'])
	obj.Flagcount("d", "disable dynamic executable", &Debug['d'])
	obj.Flagstr("extld", "use `linker` when linking in external mode", &extld)
	obj.Flagstr("extldflags", "pass `flags` to external linker", &extldflags)
	obj.Flagcount("f", "ignore version mismatch", &Debug['f'])
	obj.Flagcount("g", "disable go package data checks", &Debug['g'])
	obj.Flagcount("h", "halt on error", &Debug['h'])
	obj.Flagstr("installsuffix", "set package directory `suffix`", &flag_installsuffix)
	obj.Flagstr("k", "set field tracking `symbol`", &tracksym)
	obj.Flagfn1("linkmode", "set link `mode` (internal, external, auto)", setlinkmode)
	flag.BoolVar(&Linkshared, "linkshared", false, "link against installed Go shared libraries")
	obj.Flagcount("n", "dump symbol table", &Debug['n'])
	obj.Flagstr("o", "write output to `file`", &outfile)
	flag.Var(&rpath, "r", "set the ELF dynamic linker search `path` to dir1:dir2:...")
	obj.Flagcount("race", "enable race detector", &flag_race)
	obj.Flagcount("s", "disable symbol table", &Debug['s'])
	var flagShared int
	if Thearch.Thechar == '5' || Thearch.Thechar == '6' {
		obj.Flagcount("shared", "generate shared object (implies -linkmode external)", &flagShared)
	}
	obj.Flagstr("tmpdir", "use `directory` for temporary files", &tmpdir)
	obj.Flagcount("u", "reject unsafe packages", &Debug['u'])
	obj.Flagcount("v", "print link trace", &Debug['v'])
	obj.Flagcount("w", "disable DWARF generation", &Debug['w'])

	obj.Flagstr("cpuprofile", "write cpu profile to `file`", &cpuprofile)
	obj.Flagstr("memprofile", "write memory profile to `file`", &memprofile)
	obj.Flagint64("memprofilerate", "set runtime.MemProfileRate to `rate`", &memprofilerate)

	// Clumsy hack to preserve old two-argument -X name val syntax for old scripts.
	// Rewrite that syntax into new syntax -X name=val.
	// TODO(rsc): Delete this hack in Go 1.6 or later.
	var args []string
	for i := 0; i < len(os.Args); i++ {
		arg := os.Args[i]
		if (arg == "-X" || arg == "--X") && i+2 < len(os.Args) && !strings.Contains(os.Args[i+1], "=") {
			fmt.Fprintf(os.Stderr, "link: warning: option %s %s %s may not work in future releases; use %s %s=%s\n",
				arg, os.Args[i+1], os.Args[i+2],
				arg, os.Args[i+1], os.Args[i+2])
			args = append(args, arg)
			args = append(args, os.Args[i+1]+"="+os.Args[i+2])
			i += 2
			continue
		}
		if (strings.HasPrefix(arg, "-X=") || strings.HasPrefix(arg, "--X=")) && i+1 < len(os.Args) && strings.Count(arg, "=") == 1 {
			fmt.Fprintf(os.Stderr, "link: warning: option %s %s may not work in future releases; use %s=%s\n",
				arg, os.Args[i+1],
				arg, os.Args[i+1])
			args = append(args, arg+"="+os.Args[i+1])
			i++
			continue
		}
		args = append(args, arg)
	}
	os.Args = args

	obj.Flagparse(usage)

	startProfile()
	Ctxt.Bso = &Bso
	Ctxt.Debugvlog = int32(Debug['v'])
	if flagShared != 0 {
		if Buildmode == BuildmodeUnset {
			Buildmode = BuildmodeCShared
		} else if Buildmode != BuildmodeCShared {
			Exitf("-shared and -buildmode=%s are incompatible", Buildmode.String())
		}
	}
	if Buildmode == BuildmodeUnset {
		Buildmode = BuildmodeExe
	}

	if Buildmode != BuildmodeShared && flag.NArg() != 1 {
		usage()
	}

	if outfile == "" {
		outfile = "a.out"
		if HEADTYPE == obj.Hwindows {
			outfile += ".exe"
		}
	}

	libinit() // creates outfile

	if HEADTYPE == -1 {
		HEADTYPE = int32(headtype(goos))
	}
	Ctxt.Headtype = int(HEADTYPE)
	if headstring == "" {
		headstring = Headstr(int(HEADTYPE))
	}
	if HEADTYPE == obj.Hhaiku {
		Linkmode = LinkExternal
	}

	Thearch.Archinit()

	if Linkshared && !Iself {
		Exitf("-linkshared can only be used on elf systems")
	}

	if Debug['v'] != 0 {
		fmt.Fprintf(&Bso, "HEADER = -H%d -T0x%x -D0x%x -R0x%x\n", HEADTYPE, uint64(INITTEXT), uint64(INITDAT), uint32(INITRND))
	}
	Bso.Flush()

	if Buildmode == BuildmodeShared {
		for i := 0; i < flag.NArg(); i++ {
			arg := flag.Arg(i)
			parts := strings.SplitN(arg, "=", 2)
			var pkgpath, file string
			if len(parts) == 1 {
				pkgpath, file = "main", arg
			} else {
				pkgpath, file = parts[0], parts[1]
			}
			pkglistfornote = append(pkglistfornote, pkgpath...)
			pkglistfornote = append(pkglistfornote, '\n')
			addlibpath(Ctxt, "command line", "command line", file, pkgpath, "")
		}
	} else {
		addlibpath(Ctxt, "command line", "command line", flag.Arg(0), "main", "")
	}
	loadlib()

	if Thearch.Thechar == '5' {
		// mark some functions that are only referenced after linker code editing
		if Ctxt.Goarm == 5 {
			mark(Linkrlookup(Ctxt, "_sfloat", 0))
		}
		mark(Linklookup(Ctxt, "runtime.read_tls_fallback", 0))
	}

	checkgo()
	checkstrdata()
	deadcode()
	callgraph()

	doelf()
	if HEADTYPE == obj.Hdarwin {
		domacho()
	}
	dostkcheck()
	if HEADTYPE == obj.Hwindows {
		dope()
	}
	addexport()
	Thearch.Gentext() // trampolines, call stubs, etc.
	textbuildid()
	textaddress()
	pclntab()
	findfunctab()
	symtab()
	dodata()
	address()
	doweak()
	reloc()
	Thearch.Asmb()
	undef()
	hostlink()
	archive()
	if Debug['v'] != 0 {
		fmt.Fprintf(&Bso, "%5.2f cpu time\n", obj.Cputime())
		fmt.Fprintf(&Bso, "%d symbols\n", Ctxt.Nsymbol)
		fmt.Fprintf(&Bso, "%d liveness data\n", liveness)
	}

	Bso.Flush()

	errorexit()
}
Example #4
0
File: obj0.go Project: Harvey-OS/go
func preprocess(ctxt *obj.Link, cursym *obj.LSym) {
	// TODO(minux): add morestack short-cuts with small fixed frame-size.
	ctxt.Cursym = cursym

	// a switch for enabling/disabling instruction scheduling
	nosched := true

	if cursym.Text == nil || cursym.Text.Link == nil {
		return
	}

	p := cursym.Text
	textstksiz := p.To.Offset

	cursym.Args = p.To.Val.(int32)
	cursym.Locals = int32(textstksiz)

	/*
	 * find leaf subroutines
	 * strip NOPs
	 * expand RET
	 * expand BECOME pseudo
	 */
	if ctxt.Debugvlog != 0 {
		ctxt.Logf("%5.2f noops\n", obj.Cputime())
	}

	var q *obj.Prog
	var q1 *obj.Prog
	for p := cursym.Text; p != nil; p = p.Link {
		switch p.As {
		/* too hard, just leave alone */
		case obj.ATEXT:
			q = p

			p.Mark |= LABEL | LEAF | SYNC
			if p.Link != nil {
				p.Link.Mark |= LABEL
			}

		/* too hard, just leave alone */
		case AMOVW,
			AMOVV:
			q = p
			if p.To.Type == obj.TYPE_REG && p.To.Reg >= REG_SPECIAL {
				p.Mark |= LABEL | SYNC
				break
			}
			if p.From.Type == obj.TYPE_REG && p.From.Reg >= REG_SPECIAL {
				p.Mark |= LABEL | SYNC
			}

		/* too hard, just leave alone */
		case ASYSCALL,
			AWORD,
			ATLBWR,
			ATLBWI,
			ATLBP,
			ATLBR:
			q = p
			p.Mark |= LABEL | SYNC

		case ANOR:
			q = p
			if p.To.Type == obj.TYPE_REG {
				if p.To.Reg == REGZERO {
					p.Mark |= LABEL | SYNC
				}
			}

		case ABGEZAL,
			ABLTZAL,
			AJAL,
			obj.ADUFFZERO,
			obj.ADUFFCOPY:
			cursym.Text.Mark &^= LEAF
			fallthrough

		case AJMP,
			ABEQ,
			ABGEZ,
			ABGTZ,
			ABLEZ,
			ABLTZ,
			ABNE,
			ABFPT, ABFPF:
			if p.As == ABFPT || p.As == ABFPF {
				// We don't treat ABFPT and ABFPF as branches here,
				// so that we will always fill nop (0x0) in their
				// delay slot during assembly.
				// This is to workaround a kernel FPU emulator bug
				// where it uses the user stack to simulate the
				// instruction in the delay slot if it's not 0x0,
				// and somehow that leads to SIGSEGV when the kernel
				// jump to the stack.
				p.Mark |= SYNC
			} else {
				p.Mark |= BRANCH
			}
			q = p
			q1 = p.Pcond
			if q1 != nil {
				for q1.As == obj.ANOP {
					q1 = q1.Link
					p.Pcond = q1
				}

				if q1.Mark&LEAF == 0 {
					q1.Mark |= LABEL
				}
			}
			//else {
			//	p.Mark |= LABEL
			//}
			q1 = p.Link
			if q1 != nil {
				q1.Mark |= LABEL
			}
			continue

		case ARET:
			q = p
			if p.Link != nil {
				p.Link.Mark |= LABEL
			}
			continue

		case obj.ANOP:
			q1 = p.Link
			q.Link = q1 /* q is non-nop */
			q1.Mark |= p.Mark
			continue

		default:
			q = p
			continue
		}
	}

	var mov, add obj.As
	if ctxt.Mode&Mips64 != 0 {
		add = AADDV
		mov = AMOVV
	} else {
		add = AADDU
		mov = AMOVW
	}

	autosize := int32(0)
	var p1 *obj.Prog
	var p2 *obj.Prog
	for p := cursym.Text; p != nil; p = p.Link {
		o := p.As
		switch o {
		case obj.ATEXT:
			autosize = int32(textstksiz + ctxt.FixedFrameSize())
			if (p.Mark&LEAF != 0) && autosize <= int32(ctxt.FixedFrameSize()) {
				autosize = 0
			} else if autosize&4 != 0 && ctxt.Mode&Mips64 != 0 {
				autosize += 4
			}

			p.To.Offset = int64(autosize) - ctxt.FixedFrameSize()

			if p.From3.Offset&obj.NOSPLIT == 0 {
				p = stacksplit(ctxt, p, autosize) // emit split check
			}

			q = p

			if autosize != 0 {
				// Make sure to save link register for non-empty frame, even if
				// it is a leaf function, so that traceback works.
				// Store link register before decrement SP, so if a signal comes
				// during the execution of the function prologue, the traceback
				// code will not see a half-updated stack frame.
				q = obj.Appendp(ctxt, q)
				q.As = mov
				q.Lineno = p.Lineno
				q.From.Type = obj.TYPE_REG
				q.From.Reg = REGLINK
				q.To.Type = obj.TYPE_MEM
				q.To.Offset = int64(-autosize)
				q.To.Reg = REGSP

				q = obj.Appendp(ctxt, q)
				q.As = add
				q.Lineno = p.Lineno
				q.From.Type = obj.TYPE_CONST
				q.From.Offset = int64(-autosize)
				q.To.Type = obj.TYPE_REG
				q.To.Reg = REGSP
				q.Spadj = +autosize
			} else if cursym.Text.Mark&LEAF == 0 {
				if cursym.Text.From3.Offset&obj.NOSPLIT != 0 {
					if ctxt.Debugvlog != 0 {
						ctxt.Logf("save suppressed in: %s\n", cursym.Name)
					}

					cursym.Text.Mark |= LEAF
				}
			}

			if cursym.Text.Mark&LEAF != 0 {
				cursym.Set(obj.AttrLeaf, true)
				break
			}

			if cursym.Text.From3.Offset&obj.WRAPPER != 0 {
				// if(g->panic != nil && g->panic->argp == FP) g->panic->argp = bottom-of-frame
				//
				//	MOV	g_panic(g), R1
				//	BEQ	R1, end
				//	MOV	panic_argp(R1), R2
				//	ADD	$(autosize+FIXED_FRAME), R29, R3
				//	BNE	R2, R3, end
				//	ADD	$FIXED_FRAME, R29, R2
				//	MOV	R2, panic_argp(R1)
				// end:
				//	NOP
				//
				// The NOP is needed to give the jumps somewhere to land.
				// It is a liblink NOP, not an mips NOP: it encodes to 0 instruction bytes.

				q = obj.Appendp(ctxt, q)

				q.As = mov
				q.From.Type = obj.TYPE_MEM
				q.From.Reg = REGG
				q.From.Offset = 4 * int64(ctxt.Arch.PtrSize) // G.panic
				q.To.Type = obj.TYPE_REG
				q.To.Reg = REG_R1

				q = obj.Appendp(ctxt, q)
				q.As = ABEQ
				q.From.Type = obj.TYPE_REG
				q.From.Reg = REG_R1
				q.To.Type = obj.TYPE_BRANCH
				q.Mark |= BRANCH
				p1 = q

				q = obj.Appendp(ctxt, q)
				q.As = mov
				q.From.Type = obj.TYPE_MEM
				q.From.Reg = REG_R1
				q.From.Offset = 0 // Panic.argp
				q.To.Type = obj.TYPE_REG
				q.To.Reg = REG_R2

				q = obj.Appendp(ctxt, q)
				q.As = add
				q.From.Type = obj.TYPE_CONST
				q.From.Offset = int64(autosize) + ctxt.FixedFrameSize()
				q.Reg = REGSP
				q.To.Type = obj.TYPE_REG
				q.To.Reg = REG_R3

				q = obj.Appendp(ctxt, q)
				q.As = ABNE
				q.From.Type = obj.TYPE_REG
				q.From.Reg = REG_R2
				q.Reg = REG_R3
				q.To.Type = obj.TYPE_BRANCH
				q.Mark |= BRANCH
				p2 = q

				q = obj.Appendp(ctxt, q)
				q.As = add
				q.From.Type = obj.TYPE_CONST
				q.From.Offset = ctxt.FixedFrameSize()
				q.Reg = REGSP
				q.To.Type = obj.TYPE_REG
				q.To.Reg = REG_R2

				q = obj.Appendp(ctxt, q)
				q.As = mov
				q.From.Type = obj.TYPE_REG
				q.From.Reg = REG_R2
				q.To.Type = obj.TYPE_MEM
				q.To.Reg = REG_R1
				q.To.Offset = 0 // Panic.argp

				q = obj.Appendp(ctxt, q)

				q.As = obj.ANOP
				p1.Pcond = q
				p2.Pcond = q
			}

		case ARET:
			if p.From.Type == obj.TYPE_CONST {
				ctxt.Diag("using BECOME (%v) is not supported!", p)
				break
			}

			retSym := p.To.Sym
			p.To.Name = obj.NAME_NONE // clear fields as we may modify p to other instruction
			p.To.Sym = nil

			if cursym.Text.Mark&LEAF != 0 {
				if autosize == 0 {
					p.As = AJMP
					p.From = obj.Addr{}
					if retSym != nil { // retjmp
						p.To.Type = obj.TYPE_BRANCH
						p.To.Name = obj.NAME_EXTERN
						p.To.Sym = retSym
					} else {
						p.To.Type = obj.TYPE_MEM
						p.To.Reg = REGLINK
						p.To.Offset = 0
					}
					p.Mark |= BRANCH
					break
				}

				p.As = add
				p.From.Type = obj.TYPE_CONST
				p.From.Offset = int64(autosize)
				p.To.Type = obj.TYPE_REG
				p.To.Reg = REGSP
				p.Spadj = -autosize

				q = ctxt.NewProg()
				q.As = AJMP
				q.Lineno = p.Lineno
				q.To.Type = obj.TYPE_MEM
				q.To.Offset = 0
				q.To.Reg = REGLINK
				q.Mark |= BRANCH
				q.Spadj = +autosize

				q.Link = p.Link
				p.Link = q
				break
			}

			p.As = mov
			p.From.Type = obj.TYPE_MEM
			p.From.Offset = 0
			p.From.Reg = REGSP
			p.To.Type = obj.TYPE_REG
			p.To.Reg = REG_R4
			if retSym != nil { // retjmp from non-leaf, need to restore LINK register
				p.To.Reg = REGLINK
			}

			if autosize != 0 {
				q = ctxt.NewProg()
				q.As = add
				q.Lineno = p.Lineno
				q.From.Type = obj.TYPE_CONST
				q.From.Offset = int64(autosize)
				q.To.Type = obj.TYPE_REG
				q.To.Reg = REGSP
				q.Spadj = -autosize

				q.Link = p.Link
				p.Link = q
			}

			q1 = ctxt.NewProg()
			q1.As = AJMP
			q1.Lineno = p.Lineno
			if retSym != nil { // retjmp
				q1.To.Type = obj.TYPE_BRANCH
				q1.To.Name = obj.NAME_EXTERN
				q1.To.Sym = retSym
			} else {
				q1.To.Type = obj.TYPE_MEM
				q1.To.Offset = 0
				q1.To.Reg = REG_R4
			}
			q1.Mark |= BRANCH
			q1.Spadj = +autosize

			q1.Link = q.Link
			q.Link = q1

		case AADD,
			AADDU,
			AADDV,
			AADDVU:
			if p.To.Type == obj.TYPE_REG && p.To.Reg == REGSP && p.From.Type == obj.TYPE_CONST {
				p.Spadj = int32(-p.From.Offset)
			}
		}
	}

	if nosched {
		// if we don't do instruction scheduling, simply add
		// NOP after each branch instruction.
		for p = cursym.Text; p != nil; p = p.Link {
			if p.Mark&BRANCH != 0 {
				addnop(ctxt, p)
			}
		}
		return
	}

	// instruction scheduling
	q = nil          // p - 1
	q1 = cursym.Text // top of block
	o := 0           // count of instructions
	for p = cursym.Text; p != nil; p = p1 {
		p1 = p.Link
		o++
		if p.Mark&NOSCHED != 0 {
			if q1 != p {
				sched(ctxt, q1, q)
			}
			for ; p != nil; p = p.Link {
				if p.Mark&NOSCHED == 0 {
					break
				}
				q = p
			}
			p1 = p
			q1 = p
			o = 0
			continue
		}
		if p.Mark&(LABEL|SYNC) != 0 {
			if q1 != p {
				sched(ctxt, q1, q)
			}
			q1 = p
			o = 1
		}
		if p.Mark&(BRANCH|SYNC) != 0 {
			sched(ctxt, q1, p)
			q1 = p1
			o = 0
		}
		if o >= NSCHED {
			sched(ctxt, q1, p)
			q1 = p1
			o = 0
		}
		q = p
	}
}
Example #5
0
File: ldelf.go Project: achanda/go
func ldelf(ctxt *Link, f *bio.Reader, pkg string, length int64, pn string) {
	if ctxt.Debugvlog != 0 {
		ctxt.Logf("%5.2f ldelf %s\n", obj.Cputime(), pn)
	}

	localSymVersion := ctxt.Syms.IncVersion()
	base := f.Offset()

	var add uint64
	var e binary.ByteOrder
	var elfobj *ElfObj
	var err error
	var flag int
	var hdr *ElfHdrBytes
	var hdrbuf [64]uint8
	var info uint64
	var is64 int
	var j int
	var n int
	var name string
	var p []byte
	var r []Reloc
	var rela int
	var rp *Reloc
	var rsect *ElfSect
	var s *Symbol
	var sect *ElfSect
	var sym ElfSym
	var symbols []*Symbol
	if _, err := io.ReadFull(f, hdrbuf[:]); err != nil {
		goto bad
	}
	hdr = new(ElfHdrBytes)
	binary.Read(bytes.NewReader(hdrbuf[:]), binary.BigEndian, hdr) // only byte arrays; byte order doesn't matter
	if string(hdr.Ident[:4]) != "\x7FELF" {
		goto bad
	}
	switch hdr.Ident[5] {
	case ElfDataLsb:
		e = binary.LittleEndian

	case ElfDataMsb:
		e = binary.BigEndian

	default:
		goto bad
	}

	// read header
	elfobj = new(ElfObj)

	elfobj.e = e
	elfobj.f = f
	elfobj.base = base
	elfobj.length = length
	elfobj.name = pn

	is64 = 0
	if hdr.Ident[4] == ElfClass64 {
		is64 = 1
		hdr := new(ElfHdrBytes64)
		binary.Read(bytes.NewReader(hdrbuf[:]), binary.BigEndian, hdr) // only byte arrays; byte order doesn't matter
		elfobj.type_ = uint32(e.Uint16(hdr.Type[:]))
		elfobj.machine = uint32(e.Uint16(hdr.Machine[:]))
		elfobj.version = e.Uint32(hdr.Version[:])
		elfobj.phoff = e.Uint64(hdr.Phoff[:])
		elfobj.shoff = e.Uint64(hdr.Shoff[:])
		elfobj.flags = e.Uint32(hdr.Flags[:])
		elfobj.ehsize = uint32(e.Uint16(hdr.Ehsize[:]))
		elfobj.phentsize = uint32(e.Uint16(hdr.Phentsize[:]))
		elfobj.phnum = uint32(e.Uint16(hdr.Phnum[:]))
		elfobj.shentsize = uint32(e.Uint16(hdr.Shentsize[:]))
		elfobj.shnum = uint32(e.Uint16(hdr.Shnum[:]))
		elfobj.shstrndx = uint32(e.Uint16(hdr.Shstrndx[:]))
	} else {
		elfobj.type_ = uint32(e.Uint16(hdr.Type[:]))
		elfobj.machine = uint32(e.Uint16(hdr.Machine[:]))
		elfobj.version = e.Uint32(hdr.Version[:])
		elfobj.entry = uint64(e.Uint32(hdr.Entry[:]))
		elfobj.phoff = uint64(e.Uint32(hdr.Phoff[:]))
		elfobj.shoff = uint64(e.Uint32(hdr.Shoff[:]))
		elfobj.flags = e.Uint32(hdr.Flags[:])
		elfobj.ehsize = uint32(e.Uint16(hdr.Ehsize[:]))
		elfobj.phentsize = uint32(e.Uint16(hdr.Phentsize[:]))
		elfobj.phnum = uint32(e.Uint16(hdr.Phnum[:]))
		elfobj.shentsize = uint32(e.Uint16(hdr.Shentsize[:]))
		elfobj.shnum = uint32(e.Uint16(hdr.Shnum[:]))
		elfobj.shstrndx = uint32(e.Uint16(hdr.Shstrndx[:]))
	}

	elfobj.is64 = is64

	if uint32(hdr.Ident[6]) != elfobj.version {
		goto bad
	}

	if e.Uint16(hdr.Type[:]) != ElfTypeRelocatable {
		Errorf(nil, "%s: elf but not elf relocatable object", pn)
		return
	}

	switch SysArch.Family {
	default:
		Errorf(nil, "%s: elf %s unimplemented", pn, SysArch.Name)
		return

	case sys.MIPS64:
		if elfobj.machine != ElfMachMips || hdr.Ident[4] != ElfClass64 {
			Errorf(nil, "%s: elf object but not mips64", pn)
			return
		}

	case sys.ARM:
		if e != binary.LittleEndian || elfobj.machine != ElfMachArm || hdr.Ident[4] != ElfClass32 {
			Errorf(nil, "%s: elf object but not arm", pn)
			return
		}

	case sys.AMD64:
		if e != binary.LittleEndian || elfobj.machine != ElfMachAmd64 || hdr.Ident[4] != ElfClass64 {
			Errorf(nil, "%s: elf object but not amd64", pn)
			return
		}

	case sys.ARM64:
		if e != binary.LittleEndian || elfobj.machine != ElfMachArm64 || hdr.Ident[4] != ElfClass64 {
			Errorf(nil, "%s: elf object but not arm64", pn)
			return
		}

	case sys.I386:
		if e != binary.LittleEndian || elfobj.machine != ElfMach386 || hdr.Ident[4] != ElfClass32 {
			Errorf(nil, "%s: elf object but not 386", pn)
			return
		}

	case sys.PPC64:
		if elfobj.machine != ElfMachPower64 || hdr.Ident[4] != ElfClass64 {
			Errorf(nil, "%s: elf object but not ppc64", pn)
			return
		}

	case sys.S390X:
		if elfobj.machine != ElfMachS390 || hdr.Ident[4] != ElfClass64 {
			Errorf(nil, "%s: elf object but not s390x", pn)
			return
		}
	}

	// load section list into memory.
	elfobj.sect = make([]ElfSect, elfobj.shnum)

	elfobj.nsect = uint(elfobj.shnum)
	for i := 0; uint(i) < elfobj.nsect; i++ {
		if f.Seek(int64(uint64(base)+elfobj.shoff+uint64(int64(i)*int64(elfobj.shentsize))), 0) < 0 {
			goto bad
		}
		sect = &elfobj.sect[i]
		if is64 != 0 {
			var b ElfSectBytes64

			if err = binary.Read(f, e, &b); err != nil {
				goto bad
			}

			sect.nameoff = e.Uint32(b.Name[:])
			sect.type_ = e.Uint32(b.Type[:])
			sect.flags = e.Uint64(b.Flags[:])
			sect.addr = e.Uint64(b.Addr[:])
			sect.off = e.Uint64(b.Off[:])
			sect.size = e.Uint64(b.Size[:])
			sect.link = e.Uint32(b.Link[:])
			sect.info = e.Uint32(b.Info[:])
			sect.align = e.Uint64(b.Align[:])
			sect.entsize = e.Uint64(b.Entsize[:])
		} else {
			var b ElfSectBytes

			if err = binary.Read(f, e, &b); err != nil {
				goto bad
			}

			sect.nameoff = e.Uint32(b.Name[:])
			sect.type_ = e.Uint32(b.Type[:])
			sect.flags = uint64(e.Uint32(b.Flags[:]))
			sect.addr = uint64(e.Uint32(b.Addr[:]))
			sect.off = uint64(e.Uint32(b.Off[:]))
			sect.size = uint64(e.Uint32(b.Size[:]))
			sect.link = e.Uint32(b.Link[:])
			sect.info = e.Uint32(b.Info[:])
			sect.align = uint64(e.Uint32(b.Align[:]))
			sect.entsize = uint64(e.Uint32(b.Entsize[:]))
		}
	}

	// read section string table and translate names
	if elfobj.shstrndx >= uint32(elfobj.nsect) {
		err = fmt.Errorf("shstrndx out of range %d >= %d", elfobj.shstrndx, elfobj.nsect)
		goto bad
	}

	sect = &elfobj.sect[elfobj.shstrndx]
	if err = elfmap(elfobj, sect); err != nil {
		goto bad
	}
	for i := 0; uint(i) < elfobj.nsect; i++ {
		if elfobj.sect[i].nameoff != 0 {
			elfobj.sect[i].name = cstring(sect.base[elfobj.sect[i].nameoff:])
		}
	}

	// load string table for symbols into memory.
	elfobj.symtab = section(elfobj, ".symtab")

	if elfobj.symtab == nil {
		// our work is done here - no symbols means nothing can refer to this file
		return
	}

	if elfobj.symtab.link <= 0 || elfobj.symtab.link >= uint32(elfobj.nsect) {
		Errorf(nil, "%s: elf object has symbol table with invalid string table link", pn)
		return
	}

	elfobj.symstr = &elfobj.sect[elfobj.symtab.link]
	if is64 != 0 {
		elfobj.nsymtab = int(elfobj.symtab.size / ELF64SYMSIZE)
	} else {
		elfobj.nsymtab = int(elfobj.symtab.size / ELF32SYMSIZE)
	}

	if err = elfmap(elfobj, elfobj.symtab); err != nil {
		goto bad
	}
	if err = elfmap(elfobj, elfobj.symstr); err != nil {
		goto bad
	}

	// load text and data segments into memory.
	// they are not as small as the section lists, but we'll need
	// the memory anyway for the symbol images, so we might
	// as well use one large chunk.

	// create symbols for elfmapped sections
	for i := 0; uint(i) < elfobj.nsect; i++ {
		sect = &elfobj.sect[i]
		if sect.type_ == SHT_ARM_ATTRIBUTES && sect.name == ".ARM.attributes" {
			if err = elfmap(elfobj, sect); err != nil {
				goto bad
			}
			parseArmAttributes(ctxt, e, sect.base[:sect.size])
		}
		if (sect.type_ != ElfSectProgbits && sect.type_ != ElfSectNobits) || sect.flags&ElfSectFlagAlloc == 0 {
			continue
		}
		if sect.type_ != ElfSectNobits {
			if err = elfmap(elfobj, sect); err != nil {
				goto bad
			}
		}

		name = fmt.Sprintf("%s(%s)", pkg, sect.name)
		s = ctxt.Syms.Lookup(name, localSymVersion)

		switch int(sect.flags) & (ElfSectFlagAlloc | ElfSectFlagWrite | ElfSectFlagExec) {
		default:
			err = fmt.Errorf("unexpected flags for ELF section %s", sect.name)
			goto bad

		case ElfSectFlagAlloc:
			s.Type = obj.SRODATA

		case ElfSectFlagAlloc + ElfSectFlagWrite:
			if sect.type_ == ElfSectNobits {
				s.Type = obj.SNOPTRBSS
			} else {
				s.Type = obj.SNOPTRDATA
			}

		case ElfSectFlagAlloc + ElfSectFlagExec:
			s.Type = obj.STEXT
		}

		if sect.name == ".got" || sect.name == ".toc" {
			s.Type = obj.SELFGOT
		}
		if sect.type_ == ElfSectProgbits {
			s.P = sect.base
			s.P = s.P[:sect.size]
		}

		s.Size = int64(sect.size)
		s.Align = int32(sect.align)
		sect.sym = s
	}

	// enter sub-symbols into symbol table.
	// symbol 0 is the null symbol.
	symbols = make([]*Symbol, elfobj.nsymtab)

	for i := 1; i < elfobj.nsymtab; i++ {
		if err = readelfsym(ctxt, elfobj, i, &sym, 1, localSymVersion); err != nil {
			goto bad
		}
		symbols[i] = sym.sym
		if sym.type_ != ElfSymTypeFunc && sym.type_ != ElfSymTypeObject && sym.type_ != ElfSymTypeNone {
			continue
		}
		if sym.shndx == ElfSymShnCommon {
			s = sym.sym
			if uint64(s.Size) < sym.size {
				s.Size = int64(sym.size)
			}
			if s.Type == 0 || s.Type == obj.SXREF {
				s.Type = obj.SNOPTRBSS
			}
			continue
		}

		if uint(sym.shndx) >= elfobj.nsect || sym.shndx == 0 {
			continue
		}

		// even when we pass needSym == 1 to readelfsym, it might still return nil to skip some unwanted symbols
		if sym.sym == nil {
			continue
		}
		sect = &elfobj.sect[sym.shndx]
		if sect.sym == nil {
			if strings.HasPrefix(sym.name, ".Linfo_string") { // clang does this
				continue
			}

			if sym.name == "" && sym.type_ == 0 && sect.name == ".debug_str" {
				// This reportedly happens with clang 3.7 on ARM.
				// See issue 13139.
				continue
			}

			if strings.HasPrefix(sym.name, ".LASF") { // gcc on s390x does this
				continue
			}
			Errorf(sym.sym, "%s: sym#%d: ignoring symbol in section %d (type %d)", pn, i, sym.shndx, sym.type_)
			continue
		}

		s = sym.sym
		if s.Outer != nil {
			if s.Attr.DuplicateOK() {
				continue
			}
			Exitf("%s: duplicate symbol reference: %s in both %s and %s", pn, s.Name, s.Outer.Name, sect.sym.Name)
		}

		s.Sub = sect.sym.Sub
		sect.sym.Sub = s
		s.Type = sect.sym.Type | s.Type&^obj.SMASK | obj.SSUB
		if !s.Attr.CgoExportDynamic() {
			s.Dynimplib = "" // satisfy dynimport
		}
		s.Value = int64(sym.value)
		s.Size = int64(sym.size)
		s.Outer = sect.sym
		if sect.sym.Type == obj.STEXT {
			if s.Attr.External() && !s.Attr.DuplicateOK() {
				Errorf(s, "%s: duplicate symbol definition", pn)
			}
			s.Attr |= AttrExternal
		}

		if elfobj.machine == ElfMachPower64 {
			flag = int(sym.other) >> 5
			if 2 <= flag && flag <= 6 {
				s.Localentry = 1 << uint(flag-2)
			} else if flag == 7 {
				Errorf(s, "%s: invalid sym.other 0x%x", pn, sym.other)
			}
		}
	}

	// Sort outer lists by address, adding to textp.
	// This keeps textp in increasing address order.
	for i := 0; uint(i) < elfobj.nsect; i++ {
		s = elfobj.sect[i].sym
		if s == nil {
			continue
		}
		if s.Sub != nil {
			s.Sub = listsort(s.Sub)
		}
		if s.Type == obj.STEXT {
			if s.Attr.OnList() {
				log.Fatalf("symbol %s listed multiple times", s.Name)
			}
			s.Attr |= AttrOnList
			ctxt.Textp = append(ctxt.Textp, s)
			for s = s.Sub; s != nil; s = s.Sub {
				if s.Attr.OnList() {
					log.Fatalf("symbol %s listed multiple times", s.Name)
				}
				s.Attr |= AttrOnList
				ctxt.Textp = append(ctxt.Textp, s)
			}
		}
	}

	// load relocations
	for i := 0; uint(i) < elfobj.nsect; i++ {
		rsect = &elfobj.sect[i]
		if rsect.type_ != ElfSectRela && rsect.type_ != ElfSectRel {
			continue
		}
		if rsect.info >= uint32(elfobj.nsect) || elfobj.sect[rsect.info].base == nil {
			continue
		}
		sect = &elfobj.sect[rsect.info]
		if err = elfmap(elfobj, rsect); err != nil {
			goto bad
		}
		rela = 0
		if rsect.type_ == ElfSectRela {
			rela = 1
		}
		n = int(rsect.size / uint64(4+4*is64) / uint64(2+rela))
		r = make([]Reloc, n)
		p = rsect.base
		for j = 0; j < n; j++ {
			add = 0
			rp = &r[j]
			if is64 != 0 {
				// 64-bit rel/rela
				rp.Off = int32(e.Uint64(p))

				p = p[8:]
				info = e.Uint64(p)
				p = p[8:]
				if rela != 0 {
					add = e.Uint64(p)
					p = p[8:]
				}
			} else {
				// 32-bit rel/rela
				rp.Off = int32(e.Uint32(p))

				p = p[4:]
				info = uint64(e.Uint32(p))
				info = info>>8<<32 | info&0xff // convert to 64-bit info
				p = p[4:]
				if rela != 0 {
					add = uint64(e.Uint32(p))
					p = p[4:]
				}
			}

			if info&0xffffffff == 0 { // skip R_*_NONE relocation
				j--
				n--
				continue
			}

			if info>>32 == 0 { // absolute relocation, don't bother reading the null symbol
				rp.Sym = nil
			} else {
				if err = readelfsym(ctxt, elfobj, int(info>>32), &sym, 0, 0); err != nil {
					goto bad
				}
				sym.sym = symbols[info>>32]
				if sym.sym == nil {
					err = fmt.Errorf("%s#%d: reloc of invalid sym #%d %s shndx=%d type=%d", sect.sym.Name, j, int(info>>32), sym.name, sym.shndx, sym.type_)
					goto bad
				}

				rp.Sym = sym.sym
			}

			rp.Type = 256 + obj.RelocType(info)
			rp.Siz = relSize(ctxt, pn, uint32(info))
			if rela != 0 {
				rp.Add = int64(add)
			} else {
				// load addend from image
				if rp.Siz == 4 {
					rp.Add = int64(e.Uint32(sect.base[rp.Off:]))
				} else if rp.Siz == 8 {
					rp.Add = int64(e.Uint64(sect.base[rp.Off:]))
				} else {
					Errorf(nil, "invalid rela size %d", rp.Siz)
				}
			}

			if rp.Siz == 2 {
				rp.Add = int64(int16(rp.Add))
			}
			if rp.Siz == 4 {
				rp.Add = int64(int32(rp.Add))
			}
		}

		//print("rel %s %d %d %s %#llx\n", sect->sym->name, rp->type, rp->siz, rp->sym->name, rp->add);
		sort.Sort(rbyoff(r[:n]))
		// just in case

		s = sect.sym
		s.R = r
		s.R = s.R[:n]
	}

	return

bad:
	Errorf(nil, "%s: malformed elf file: %v", pn, err)
}
Example #6
0
File: main.go Project: hurkgu/go
// Main is the main entry point for the linker code.
func Main() {
	ctxt := linknew(SysArch)
	ctxt.Bso = bufio.NewWriter(os.Stdout)

	nerrors = 0
	HEADTYPE = -1
	Linkmode = LinkAuto

	// For testing behavior of go command when tools crash silently.
	// Undocumented, not in standard flag parser to avoid
	// exposing in usage message.
	for _, arg := range os.Args {
		if arg == "-crash_for_testing" {
			os.Exit(2)
		}
	}

	// TODO(matloob): define these above and then check flag values here
	if SysArch.Family == sys.AMD64 && obj.Getgoos() == "plan9" {
		flag.BoolVar(&Flag8, "8", false, "use 64-bit addresses in symbol table")
	}
	obj.Flagfn1("B", "add an ELF NT_GNU_BUILD_ID `note` when using ELF", addbuildinfo)
	obj.Flagfn1("L", "add specified `directory` to library path", func(a string) { Lflag(ctxt, a) })
	obj.Flagfn1("H", "set header `type`", setheadtype)
	obj.Flagfn0("V", "print version and exit", doversion)
	obj.Flagfn1("X", "add string value `definition` of the form importpath.name=value", func(s string) { addstrdata1(ctxt, s) })
	obj.Flagcount("v", "print link trace", &ctxt.Debugvlog)
	obj.Flagfn1("linkmode", "set link `mode` (internal, external, auto)", setlinkmode)
	var flagShared bool
	if SysArch.InFamily(sys.ARM, sys.AMD64) {
		flag.BoolVar(&flagShared, "shared", false, "generate shared object (implies -linkmode external)")
	}

	obj.Flagparse(usage)

	startProfile()
	if flagShared {
		if Buildmode == BuildmodeUnset {
			Buildmode = BuildmodeCShared
		} else if Buildmode != BuildmodeCShared {
			Exitf("-shared and -buildmode=%s are incompatible", Buildmode.String())
		}
	}
	if Buildmode == BuildmodeUnset {
		Buildmode = BuildmodeExe
	}

	if Buildmode != BuildmodeShared && flag.NArg() != 1 {
		usage()
	}

	if *flagOutfile == "" {
		*flagOutfile = "a.out"
		if HEADTYPE == obj.Hwindows {
			*flagOutfile += ".exe"
		}
	}

	interpreter = *flagInterpreter

	libinit(ctxt) // creates outfile

	if HEADTYPE == -1 {
		HEADTYPE = int32(headtype(goos))
	}
	ctxt.Headtype = int(HEADTYPE)
	if headstring == "" {
		headstring = Headstr(int(HEADTYPE))
	}

	Thearch.Archinit(ctxt)

	if *FlagLinkshared && !Iself {
		Exitf("-linkshared can only be used on elf systems")
	}

	if ctxt.Debugvlog != 0 {
		ctxt.Logf("HEADER = -H%d -T0x%x -D0x%x -R0x%x\n", HEADTYPE, uint64(*FlagTextAddr), uint64(*FlagDataAddr), uint32(*FlagRound))
	}

	if Buildmode == BuildmodeShared {
		for i := 0; i < flag.NArg(); i++ {
			arg := flag.Arg(i)
			parts := strings.SplitN(arg, "=", 2)
			var pkgpath, file string
			if len(parts) == 1 {
				pkgpath, file = "main", arg
			} else {
				pkgpath, file = parts[0], parts[1]
			}
			pkglistfornote = append(pkglistfornote, pkgpath...)
			pkglistfornote = append(pkglistfornote, '\n')
			addlibpath(ctxt, "command line", "command line", file, pkgpath, "")
		}
	} else {
		addlibpath(ctxt, "command line", "command line", flag.Arg(0), "main", "")
	}
	ctxt.loadlib()

	ctxt.checkstrdata()
	deadcode(ctxt)
	fieldtrack(ctxt)
	ctxt.callgraph()

	ctxt.doelf()
	if HEADTYPE == obj.Hdarwin {
		ctxt.domacho()
	}
	ctxt.dostkcheck()
	if HEADTYPE == obj.Hwindows {
		ctxt.dope()
	}
	ctxt.addexport()
	Thearch.Gentext(ctxt) // trampolines, call stubs, etc.
	ctxt.textbuildid()
	ctxt.textaddress()
	ctxt.pclntab()
	ctxt.findfunctab()
	ctxt.symtab()
	ctxt.dodata()
	ctxt.address()
	ctxt.reloc()
	Thearch.Asmb(ctxt)
	ctxt.undef()
	ctxt.hostlink()
	ctxt.archive()
	if ctxt.Debugvlog != 0 {
		ctxt.Logf("%5.2f cpu time\n", obj.Cputime())
		ctxt.Logf("%d symbols\n", len(ctxt.Allsym))
		ctxt.Logf("%d liveness data\n", liveness)
	}

	ctxt.Bso.Flush()

	errorexit()
}
Example #7
0
File: asm0.go Project: danny8002/go
func span0(ctxt *obj.Link, cursym *obj.LSym) {
	p := cursym.Text
	if p == nil || p.Link == nil { // handle external functions and ELF section symbols
		return
	}
	ctxt.Cursym = cursym
	ctxt.Autosize = int32(p.To.Offset + 8)

	if oprange[AOR&obj.AMask].start == nil {
		buildop(ctxt)
	}

	c := int64(0)
	p.Pc = c

	var m int
	var o *Optab
	for p = p.Link; p != nil; p = p.Link {
		ctxt.Curp = p
		p.Pc = c
		o = oplook(ctxt, p)
		m = int(o.size)
		if m == 0 {
			if p.As != obj.ANOP && p.As != obj.AFUNCDATA && p.As != obj.APCDATA && p.As != obj.AUSEFIELD {
				ctxt.Diag("zero-width instruction\n%v", p)
			}
			continue
		}

		c += int64(m)
	}

	cursym.Size = c

	/*
	 * if any procedure is large enough to
	 * generate a large SBRA branch, then
	 * generate extra passes putting branches
	 * around jmps to fix. this is rare.
	 */
	bflag := 1

	var otxt int64
	var q *obj.Prog
	for bflag != 0 {
		if ctxt.Debugvlog != 0 {
			fmt.Fprintf(ctxt.Bso, "%5.2f span1\n", obj.Cputime())
		}
		bflag = 0
		c = 0
		for p = cursym.Text.Link; p != nil; p = p.Link {
			p.Pc = c
			o = oplook(ctxt, p)

			// very large conditional branches
			if o.type_ == 6 && p.Pcond != nil {
				otxt = p.Pcond.Pc - c
				if otxt < -(1<<17)+10 || otxt >= (1<<17)-10 {
					q = ctxt.NewProg()
					q.Link = p.Link
					p.Link = q
					q.As = AJMP
					q.Lineno = p.Lineno
					q.To.Type = obj.TYPE_BRANCH
					q.Pcond = p.Pcond
					p.Pcond = q
					q = ctxt.NewProg()
					q.Link = p.Link
					p.Link = q
					q.As = AJMP
					q.Lineno = p.Lineno
					q.To.Type = obj.TYPE_BRANCH
					q.Pcond = q.Link.Link

					addnop(ctxt, p.Link)
					addnop(ctxt, p)
					bflag = 1
				}
			}

			m = int(o.size)
			if m == 0 {
				if p.As != obj.ANOP && p.As != obj.AFUNCDATA && p.As != obj.APCDATA && p.As != obj.AUSEFIELD {
					ctxt.Diag("zero-width instruction\n%v", p)
				}
				continue
			}

			c += int64(m)
		}

		cursym.Size = c
	}

	c += -c & (FuncAlign - 1)
	cursym.Size = c

	/*
	 * lay out the code, emitting code and data relocations.
	 */

	obj.Symgrow(ctxt, cursym, cursym.Size)

	bp := cursym.P
	var i int32
	var out [4]uint32
	for p := cursym.Text.Link; p != nil; p = p.Link {
		ctxt.Pc = p.Pc
		ctxt.Curp = p
		o = oplook(ctxt, p)
		if int(o.size) > 4*len(out) {
			log.Fatalf("out array in span0 is too small, need at least %d for %v", o.size/4, p)
		}
		asmout(ctxt, p, o, out[:])
		for i = 0; i < int32(o.size/4); i++ {
			ctxt.Arch.ByteOrder.PutUint32(bp, out[i])
			bp = bp[4:]
		}
	}
}
Example #8
0
File: main.go Project: achanda/go
// Main is the main entry point for the linker code.
func Main() {
	ctxt := linknew(SysArch)
	ctxt.Bso = bufio.NewWriter(os.Stdout)

	// For testing behavior of go command when tools crash silently.
	// Undocumented, not in standard flag parser to avoid
	// exposing in usage message.
	for _, arg := range os.Args {
		if arg == "-crash_for_testing" {
			os.Exit(2)
		}
	}

	// TODO(matloob): define these above and then check flag values here
	if SysArch.Family == sys.AMD64 && obj.GOOS == "plan9" {
		flag.BoolVar(&Flag8, "8", false, "use 64-bit addresses in symbol table")
	}
	obj.Flagfn1("B", "add an ELF NT_GNU_BUILD_ID `note` when using ELF", addbuildinfo)
	obj.Flagfn1("L", "add specified `directory` to library path", func(a string) { Lflag(ctxt, a) })
	obj.Flagfn0("V", "print version and exit", doversion)
	obj.Flagfn1("X", "add string value `definition` of the form importpath.name=value", func(s string) { addstrdata1(ctxt, s) })
	obj.Flagcount("v", "print link trace", &ctxt.Debugvlog)

	obj.Flagparse(usage)

	startProfile()
	if Buildmode == BuildmodeUnset {
		Buildmode = BuildmodeExe
	}

	if Buildmode != BuildmodeShared && flag.NArg() != 1 {
		usage()
	}

	if *flagOutfile == "" {
		*flagOutfile = "a.out"
		if Headtype == obj.Hwindows || Headtype == obj.Hwindowsgui {
			*flagOutfile += ".exe"
		}
	}

	interpreter = *flagInterpreter

	libinit(ctxt) // creates outfile

	if Headtype == obj.Hunknown {
		Headtype.Set(obj.GOOS)
	}

	ctxt.computeTLSOffset()
	Thearch.Archinit(ctxt)

	if *FlagLinkshared && !Iself {
		Exitf("-linkshared can only be used on elf systems")
	}

	if ctxt.Debugvlog != 0 {
		ctxt.Logf("HEADER = -H%d -T0x%x -D0x%x -R0x%x\n", Headtype, uint64(*FlagTextAddr), uint64(*FlagDataAddr), uint32(*FlagRound))
	}

	switch Buildmode {
	case BuildmodeShared:
		for i := 0; i < flag.NArg(); i++ {
			arg := flag.Arg(i)
			parts := strings.SplitN(arg, "=", 2)
			var pkgpath, file string
			if len(parts) == 1 {
				pkgpath, file = "main", arg
			} else {
				pkgpath, file = parts[0], parts[1]
			}
			pkglistfornote = append(pkglistfornote, pkgpath...)
			pkglistfornote = append(pkglistfornote, '\n')
			addlibpath(ctxt, "command line", "command line", file, pkgpath, "")
		}
	case BuildmodePlugin:
		pluginName := strings.TrimSuffix(filepath.Base(flag.Arg(0)), ".a")
		addlibpath(ctxt, "command line", "command line", flag.Arg(0), pluginName, "")
	default:
		addlibpath(ctxt, "command line", "command line", flag.Arg(0), "main", "")
	}
	ctxt.loadlib()

	ctxt.checkstrdata()
	deadcode(ctxt)
	fieldtrack(ctxt)
	ctxt.callgraph()

	ctxt.doelf()
	if Headtype == obj.Hdarwin {
		ctxt.domacho()
	}
	ctxt.dostkcheck()
	if Headtype == obj.Hwindows || Headtype == obj.Hwindowsgui {
		ctxt.dope()
	}
	ctxt.addexport()
	Thearch.Gentext(ctxt) // trampolines, call stubs, etc.
	ctxt.textbuildid()
	ctxt.textaddress()
	ctxt.pclntab()
	ctxt.findfunctab()
	ctxt.typelink()
	ctxt.symtab()
	ctxt.dodata()
	ctxt.address()
	ctxt.reloc()
	Thearch.Asmb(ctxt)
	ctxt.undef()
	ctxt.hostlink()
	ctxt.archive()
	if ctxt.Debugvlog != 0 {
		ctxt.Logf("%5.2f cpu time\n", obj.Cputime())
		ctxt.Logf("%d symbols\n", len(ctxt.Syms.Allsym))
		ctxt.Logf("%d liveness data\n", liveness)
	}

	ctxt.Bso.Flush()

	errorexit()
}
Example #9
0
func ldshlibsyms(shlib string) {
	libpath := findshlib(shlib)
	if libpath == "" {
		return
	}
	for _, processedlib := range Ctxt.Shlibs {
		if processedlib.Path == libpath {
			return
		}
	}
	if Ctxt.Debugvlog > 1 && Ctxt.Bso != nil {
		fmt.Fprintf(Ctxt.Bso, "%5.2f ldshlibsyms: found library with name %s at %s\n", obj.Cputime(), shlib, libpath)
		Ctxt.Bso.Flush()
	}

	f, err := elf.Open(libpath)
	if err != nil {
		Diag("cannot open shared library: %s", libpath)
		return
	}

	hash, err := readnote(f, ELF_NOTE_GO_NAME, ELF_NOTE_GOABIHASH_TAG)
	if err != nil {
		Diag("cannot read ABI hash from shared library %s: %v", libpath, err)
		return
	}

	depsbytes, err := readnote(f, ELF_NOTE_GO_NAME, ELF_NOTE_GODEPS_TAG)
	if err != nil {
		Diag("cannot read dep list from shared library %s: %v", libpath, err)
		return
	}
	deps := strings.Split(string(depsbytes), "\n")

	syms, err := f.DynamicSymbols()
	if err != nil {
		Diag("cannot read symbols from shared library: %s", libpath)
		return
	}
	for _, elfsym := range syms {
		if elf.ST_TYPE(elfsym.Info) == elf.STT_NOTYPE || elf.ST_TYPE(elfsym.Info) == elf.STT_SECTION {
			continue
		}
		lsym := Linklookup(Ctxt, elfsym.Name, 0)
		if lsym.Type != 0 && lsym.Type != obj.SDYNIMPORT && lsym.Dupok == 0 {
			if (lsym.Type != obj.SBSS && lsym.Type != obj.SNOPTRBSS) || len(lsym.R) != 0 || len(lsym.P) != 0 || f.Sections[elfsym.Section].Type != elf.SHT_NOBITS {
				Diag("Found duplicate symbol %s reading from %s, first found in %s", elfsym.Name, shlib, lsym.File)
			}
			if lsym.Size > int64(elfsym.Size) {
				// If the existing symbol is a BSS value that is
				// larger than the one read from the shared library,
				// keep references to that.  Conversely, if the
				// version from the shared libray is larger, we want
				// to make all references be to that.
				continue
			}
		}
		lsym.Type = obj.SDYNIMPORT
		lsym.ElfType = elf.ST_TYPE(elfsym.Info)
		lsym.Size = int64(elfsym.Size)
		if elfsym.Section != elf.SHN_UNDEF {
			// Set .File for the library that actually defines the symbol.
			lsym.File = libpath
			// The decodetype_* functions in decodetype.go need access to
			// the type data.
			if strings.HasPrefix(lsym.Name, "type.") && !strings.HasPrefix(lsym.Name, "type..") {
				lsym.P = readelfsymboldata(f, &elfsym)
			}
		}
	}

	// We might have overwritten some functions above (this tends to happen for the
	// autogenerated type equality/hashing functions) and we don't want to generated
	// pcln table entries for these any more so unstitch them from the Textp linked
	// list.
	var last *LSym

	for s := Ctxt.Textp; s != nil; s = s.Next {
		if s.Type == obj.SDYNIMPORT {
			continue
		}

		if last == nil {
			Ctxt.Textp = s
		} else {
			last.Next = s
		}
		last = s
	}

	if last == nil {
		Ctxt.Textp = nil
		Ctxt.Etextp = nil
	} else {
		last.Next = nil
		Ctxt.Etextp = last
	}

	Ctxt.Shlibs = append(Ctxt.Shlibs, Shlib{Path: libpath, Hash: hash, Deps: deps, File: f})
}
Example #10
0
File: obj9.go Project: gmwu/go
func preprocess(ctxt *obj.Link, cursym *obj.LSym) {
	// TODO(minux): add morestack short-cuts with small fixed frame-size.
	ctxt.Cursym = cursym

	if cursym.Text == nil || cursym.Text.Link == nil {
		return
	}

	p := cursym.Text
	textstksiz := p.To.Offset
	if textstksiz == -8 {
		// Compatibility hack.
		p.From3.Offset |= obj.NOFRAME
		textstksiz = 0
	}
	if textstksiz%8 != 0 {
		ctxt.Diag("frame size %d not a multiple of 8", textstksiz)
	}
	if p.From3.Offset&obj.NOFRAME != 0 {
		if textstksiz != 0 {
			ctxt.Diag("NOFRAME functions must have a frame size of 0, not %d", textstksiz)
		}
	}

	cursym.Args = p.To.Val.(int32)
	cursym.Locals = int32(textstksiz)

	/*
	 * find leaf subroutines
	 * strip NOPs
	 * expand RET
	 * expand BECOME pseudo
	 */
	if ctxt.Debugvlog != 0 {
		fmt.Fprintf(ctxt.Bso, "%5.2f noops\n", obj.Cputime())
	}
	ctxt.Bso.Flush()

	var q *obj.Prog
	var q1 *obj.Prog
	for p := cursym.Text; p != nil; p = p.Link {
		switch p.As {
		/* too hard, just leave alone */
		case obj.ATEXT:
			q = p

			p.Mark |= LABEL | LEAF | SYNC
			if p.Link != nil {
				p.Link.Mark |= LABEL
			}

		case ANOR:
			q = p
			if p.To.Type == obj.TYPE_REG {
				if p.To.Reg == REGZERO {
					p.Mark |= LABEL | SYNC
				}
			}

		case ALWAR,
			ASTWCCC,
			AECIWX,
			AECOWX,
			AEIEIO,
			AICBI,
			AISYNC,
			ATLBIE,
			ATLBIEL,
			ASLBIA,
			ASLBIE,
			ASLBMFEE,
			ASLBMFEV,
			ASLBMTE,
			ADCBF,
			ADCBI,
			ADCBST,
			ADCBT,
			ADCBTST,
			ADCBZ,
			ASYNC,
			ATLBSYNC,
			APTESYNC,
			ATW,
			AWORD,
			ARFI,
			ARFCI,
			ARFID,
			AHRFID:
			q = p
			p.Mark |= LABEL | SYNC
			continue

		case AMOVW, AMOVWZ, AMOVD:
			q = p
			if p.From.Reg >= REG_SPECIAL || p.To.Reg >= REG_SPECIAL {
				p.Mark |= LABEL | SYNC
			}
			continue

		case AFABS,
			AFABSCC,
			AFADD,
			AFADDCC,
			AFCTIW,
			AFCTIWCC,
			AFCTIWZ,
			AFCTIWZCC,
			AFDIV,
			AFDIVCC,
			AFMADD,
			AFMADDCC,
			AFMOVD,
			AFMOVDU,
			/* case AFMOVDS: */
			AFMOVS,
			AFMOVSU,

			/* case AFMOVSD: */
			AFMSUB,
			AFMSUBCC,
			AFMUL,
			AFMULCC,
			AFNABS,
			AFNABSCC,
			AFNEG,
			AFNEGCC,
			AFNMADD,
			AFNMADDCC,
			AFNMSUB,
			AFNMSUBCC,
			AFRSP,
			AFRSPCC,
			AFSUB,
			AFSUBCC:
			q = p

			p.Mark |= FLOAT
			continue

		case ABL,
			ABCL,
			obj.ADUFFZERO,
			obj.ADUFFCOPY:
			cursym.Text.Mark &^= LEAF
			fallthrough

		case ABC,
			ABEQ,
			ABGE,
			ABGT,
			ABLE,
			ABLT,
			ABNE,
			ABR,
			ABVC,
			ABVS:
			p.Mark |= BRANCH
			q = p
			q1 = p.Pcond
			if q1 != nil {
				for q1.As == obj.ANOP {
					q1 = q1.Link
					p.Pcond = q1
				}

				if q1.Mark&LEAF == 0 {
					q1.Mark |= LABEL
				}
			} else {
				p.Mark |= LABEL
			}
			q1 = p.Link
			if q1 != nil {
				q1.Mark |= LABEL
			}
			continue

		case AFCMPO, AFCMPU:
			q = p
			p.Mark |= FCMP | FLOAT
			continue

		case obj.ARET:
			q = p
			if p.Link != nil {
				p.Link.Mark |= LABEL
			}
			continue

		case obj.ANOP:
			q1 = p.Link
			q.Link = q1 /* q is non-nop */
			q1.Mark |= p.Mark
			continue

		default:
			q = p
			continue
		}
	}

	autosize := int32(0)
	var aoffset int
	var mov int
	var o int
	var p1 *obj.Prog
	var p2 *obj.Prog
	for p := cursym.Text; p != nil; p = p.Link {
		o = int(p.As)
		switch o {
		case obj.ATEXT:
			mov = AMOVD
			aoffset = 0
			autosize = int32(textstksiz)

			if p.Mark&LEAF != 0 && autosize == 0 && p.From3.Offset&obj.NOFRAME == 0 {
				// A leaf function with no locals has no frame.
				p.From3.Offset |= obj.NOFRAME
			}

			if p.From3.Offset&obj.NOFRAME == 0 {
				// If there is a stack frame at all, it includes
				// space to save the LR.
				autosize += int32(ctxt.FixedFrameSize())
			}

			p.To.Offset = int64(autosize)

			q = p

			if ctxt.Flag_shared != 0 && cursym.Name != "runtime.duffzero" && cursym.Name != "runtime.duffcopy" {
				// When compiling Go into PIC, all functions must start
				// with instructions to load the TOC pointer into r2:
				//
				//	addis r2, r12, .TOC.-func@ha
				//	addi r2, r2, .TOC.-func@l+4
				//
				// We could probably skip this prologue in some situations
				// but it's a bit subtle. However, it is both safe and
				// necessary to leave the prologue off duffzero and
				// duffcopy as we rely on being able to jump to a specific
				// instruction offset for them.
				//
				// These are AWORDS because there is no (afaict) way to
				// generate the addis instruction except as part of the
				// load of a large constant, and in that case there is no
				// way to use r12 as the source.
				q = obj.Appendp(ctxt, q)
				q.As = AWORD
				q.Lineno = p.Lineno
				q.From.Type = obj.TYPE_CONST
				q.From.Offset = 0x3c4c0000
				q = obj.Appendp(ctxt, q)
				q.As = AWORD
				q.Lineno = p.Lineno
				q.From.Type = obj.TYPE_CONST
				q.From.Offset = 0x38420000
				rel := obj.Addrel(ctxt.Cursym)
				rel.Off = 0
				rel.Siz = 8
				rel.Sym = obj.Linklookup(ctxt, ".TOC.", 0)
				rel.Type = obj.R_ADDRPOWER_PCREL
			}

			if cursym.Text.From3.Offset&obj.NOSPLIT == 0 {
				q = stacksplit(ctxt, q, autosize) // emit split check
			}

			if autosize != 0 {
				/* use MOVDU to adjust R1 when saving R31, if autosize is small */
				if cursym.Text.Mark&LEAF == 0 && autosize >= -BIG && autosize <= BIG {
					mov = AMOVDU
					aoffset = int(-autosize)
				} else {
					q = obj.Appendp(ctxt, q)
					q.As = AADD
					q.Lineno = p.Lineno
					q.From.Type = obj.TYPE_CONST
					q.From.Offset = int64(-autosize)
					q.To.Type = obj.TYPE_REG
					q.To.Reg = REGSP
					q.Spadj = +autosize
				}
			} else if cursym.Text.Mark&LEAF == 0 {
				// A very few functions that do not return to their caller
				// (e.g. gogo) are not identified as leaves but still have
				// no frame.
				cursym.Text.Mark |= LEAF
			}

			if cursym.Text.Mark&LEAF != 0 {
				cursym.Leaf = 1
				break
			}

			q = obj.Appendp(ctxt, q)
			q.As = AMOVD
			q.Lineno = p.Lineno
			q.From.Type = obj.TYPE_REG
			q.From.Reg = REG_LR
			q.To.Type = obj.TYPE_REG
			q.To.Reg = REGTMP

			q = obj.Appendp(ctxt, q)
			q.As = int16(mov)
			q.Lineno = p.Lineno
			q.From.Type = obj.TYPE_REG
			q.From.Reg = REGTMP
			q.To.Type = obj.TYPE_MEM
			q.To.Offset = int64(aoffset)
			q.To.Reg = REGSP
			if q.As == AMOVDU {
				q.Spadj = int32(-aoffset)
			}

			if ctxt.Flag_shared != 0 {
				q = obj.Appendp(ctxt, q)
				q.As = AMOVD
				q.Lineno = p.Lineno
				q.From.Type = obj.TYPE_REG
				q.From.Reg = REG_R2
				q.To.Type = obj.TYPE_MEM
				q.To.Reg = REGSP
				q.To.Offset = 24
			}

			if cursym.Text.From3.Offset&obj.WRAPPER != 0 {
				// if(g->panic != nil && g->panic->argp == FP) g->panic->argp = bottom-of-frame
				//
				//	MOVD g_panic(g), R3
				//	CMP R0, R3
				//	BEQ end
				//	MOVD panic_argp(R3), R4
				//	ADD $(autosize+8), R1, R5
				//	CMP R4, R5
				//	BNE end
				//	ADD $8, R1, R6
				//	MOVD R6, panic_argp(R3)
				// end:
				//	NOP
				//
				// The NOP is needed to give the jumps somewhere to land.
				// It is a liblink NOP, not a ppc64 NOP: it encodes to 0 instruction bytes.

				q = obj.Appendp(ctxt, q)

				q.As = AMOVD
				q.From.Type = obj.TYPE_MEM
				q.From.Reg = REGG
				q.From.Offset = 4 * int64(ctxt.Arch.Ptrsize) // G.panic
				q.To.Type = obj.TYPE_REG
				q.To.Reg = REG_R3

				q = obj.Appendp(ctxt, q)
				q.As = ACMP
				q.From.Type = obj.TYPE_REG
				q.From.Reg = REG_R0
				q.To.Type = obj.TYPE_REG
				q.To.Reg = REG_R3

				q = obj.Appendp(ctxt, q)
				q.As = ABEQ
				q.To.Type = obj.TYPE_BRANCH
				p1 = q

				q = obj.Appendp(ctxt, q)
				q.As = AMOVD
				q.From.Type = obj.TYPE_MEM
				q.From.Reg = REG_R3
				q.From.Offset = 0 // Panic.argp
				q.To.Type = obj.TYPE_REG
				q.To.Reg = REG_R4

				q = obj.Appendp(ctxt, q)
				q.As = AADD
				q.From.Type = obj.TYPE_CONST
				q.From.Offset = int64(autosize) + ctxt.FixedFrameSize()
				q.Reg = REGSP
				q.To.Type = obj.TYPE_REG
				q.To.Reg = REG_R5

				q = obj.Appendp(ctxt, q)
				q.As = ACMP
				q.From.Type = obj.TYPE_REG
				q.From.Reg = REG_R4
				q.To.Type = obj.TYPE_REG
				q.To.Reg = REG_R5

				q = obj.Appendp(ctxt, q)
				q.As = ABNE
				q.To.Type = obj.TYPE_BRANCH
				p2 = q

				q = obj.Appendp(ctxt, q)
				q.As = AADD
				q.From.Type = obj.TYPE_CONST
				q.From.Offset = ctxt.FixedFrameSize()
				q.Reg = REGSP
				q.To.Type = obj.TYPE_REG
				q.To.Reg = REG_R6

				q = obj.Appendp(ctxt, q)
				q.As = AMOVD
				q.From.Type = obj.TYPE_REG
				q.From.Reg = REG_R6
				q.To.Type = obj.TYPE_MEM
				q.To.Reg = REG_R3
				q.To.Offset = 0 // Panic.argp

				q = obj.Appendp(ctxt, q)

				q.As = obj.ANOP
				p1.Pcond = q
				p2.Pcond = q
			}

		case obj.ARET:
			if p.From.Type == obj.TYPE_CONST {
				ctxt.Diag("using BECOME (%v) is not supported!", p)
				break
			}

			retTarget := p.To.Sym

			if cursym.Text.Mark&LEAF != 0 {
				if autosize == 0 {
					p.As = ABR
					p.From = obj.Addr{}
					if retTarget == nil {
						p.To.Type = obj.TYPE_REG
						p.To.Reg = REG_LR
					} else {
						p.To.Type = obj.TYPE_BRANCH
						p.To.Sym = retTarget
					}
					p.Mark |= BRANCH
					break
				}

				p.As = AADD
				p.From.Type = obj.TYPE_CONST
				p.From.Offset = int64(autosize)
				p.To.Type = obj.TYPE_REG
				p.To.Reg = REGSP
				p.Spadj = -autosize

				q = ctxt.NewProg()
				q.As = ABR
				q.Lineno = p.Lineno
				q.To.Type = obj.TYPE_REG
				q.To.Reg = REG_LR
				q.Mark |= BRANCH
				q.Spadj = +autosize

				q.Link = p.Link
				p.Link = q
				break
			}

			p.As = AMOVD
			p.From.Type = obj.TYPE_MEM
			p.From.Offset = 0
			p.From.Reg = REGSP
			p.To.Type = obj.TYPE_REG
			p.To.Reg = REGTMP

			q = ctxt.NewProg()
			q.As = AMOVD
			q.Lineno = p.Lineno
			q.From.Type = obj.TYPE_REG
			q.From.Reg = REGTMP
			q.To.Type = obj.TYPE_REG
			q.To.Reg = REG_LR

			q.Link = p.Link
			p.Link = q
			p = q

			if false {
				// Debug bad returns
				q = ctxt.NewProg()

				q.As = AMOVD
				q.Lineno = p.Lineno
				q.From.Type = obj.TYPE_MEM
				q.From.Offset = 0
				q.From.Reg = REGTMP
				q.To.Type = obj.TYPE_REG
				q.To.Reg = REGTMP

				q.Link = p.Link
				p.Link = q
				p = q
			}

			if autosize != 0 {
				q = ctxt.NewProg()
				q.As = AADD
				q.Lineno = p.Lineno
				q.From.Type = obj.TYPE_CONST
				q.From.Offset = int64(autosize)
				q.To.Type = obj.TYPE_REG
				q.To.Reg = REGSP
				q.Spadj = -autosize

				q.Link = p.Link
				p.Link = q
			}

			q1 = ctxt.NewProg()
			q1.As = ABR
			q1.Lineno = p.Lineno
			if retTarget == nil {
				q1.To.Type = obj.TYPE_REG
				q1.To.Reg = REG_LR
			} else {
				q1.To.Type = obj.TYPE_BRANCH
				q1.To.Sym = retTarget
			}
			q1.Mark |= BRANCH
			q1.Spadj = +autosize

			q1.Link = q.Link
			q.Link = q1
		case AADD:
			if p.To.Type == obj.TYPE_REG && p.To.Reg == REGSP && p.From.Type == obj.TYPE_CONST {
				p.Spadj = int32(-p.From.Offset)
			}
		}
	}
}
Example #11
0
File: asm.go Project: sreis/go
func asmb() {
	if ld.Debug['v'] != 0 {
		fmt.Fprintf(&ld.Bso, "%5.2f asmb\n", obj.Cputime())
	}
	ld.Bso.Flush()

	if ld.Debug['v'] != 0 {
		fmt.Fprintf(&ld.Bso, "%5.2f codeblk\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))

	machlink := int64(0)
	if ld.HEADTYPE == obj.Hdarwin {
		if ld.Debug['v'] != 0 {
			fmt.Fprintf(&ld.Bso, "%5.2f dwarf\n", obj.Cputime())
		}

		dwarfoff := ld.Rnd(int64(uint64(ld.HEADR)+ld.Segtext.Length), int64(ld.INITRND)) + ld.Rnd(int64(ld.Segdata.Filelen), int64(ld.INITRND))
		ld.Cseek(dwarfoff)

		ld.Segdwarf.Fileoff = uint64(ld.Cpos())
		ld.Dwarfemitdebugsections()
		ld.Segdwarf.Filelen = uint64(ld.Cpos()) - ld.Segdwarf.Fileoff

		machlink = ld.Domacholink()
	}

	switch ld.HEADTYPE {
	default:
		ld.Diag("unknown header type %d", ld.HEADTYPE)
		fallthrough

	case obj.Hplan9,
		obj.Helf:
		break

	case obj.Hdarwin:
		ld.Debug['8'] = 1 /* 64-bit addresses */

	case obj.Hlinux,
		obj.Hfreebsd,
		obj.Hnetbsd,
		obj.Hopenbsd,
		obj.Hdragonfly,
		obj.Hsolaris:
		ld.Debug['8'] = 1 /* 64-bit addresses */

	case obj.Hnacl,
		obj.Hwindows:
		break
	}

	ld.Symsize = 0
	ld.Spsize = 0
	ld.Lcsize = 0
	symo := int64(0)
	if ld.Debug['s'] == 0 {
		if ld.Debug['v'] != 0 {
			fmt.Fprintf(&ld.Bso, "%5.2f sym\n", obj.Cputime())
		}
		ld.Bso.Flush()
		switch ld.HEADTYPE {
		default:
		case obj.Hplan9,
			obj.Helf:
			ld.Debug['s'] = 1
			symo = int64(ld.Segdata.Fileoff + ld.Segdata.Filelen)

		case obj.Hdarwin:
			symo = int64(ld.Segdwarf.Fileoff + uint64(ld.Rnd(int64(ld.Segdwarf.Filelen), int64(ld.INITRND))) + uint64(machlink))

		case obj.Hlinux,
			obj.Hfreebsd,
			obj.Hnetbsd,
			obj.Hopenbsd,
			obj.Hdragonfly,
			obj.Hsolaris,
			obj.Hnacl:
			symo = int64(ld.Segdata.Fileoff + ld.Segdata.Filelen)
			symo = ld.Rnd(symo, int64(ld.INITRND))

		case obj.Hwindows:
			symo = int64(ld.Segdata.Fileoff + ld.Segdata.Filelen)
			symo = ld.Rnd(symo, ld.PEFILEALIGN)
		}

		ld.Cseek(symo)
		switch ld.HEADTYPE {
		default:
			if ld.Iself {
				ld.Cseek(symo)
				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()
			}

		case obj.Hwindows:
			if ld.Debug['v'] != 0 {
				fmt.Fprintf(&ld.Bso, "%5.2f dwarf\n", obj.Cputime())
			}

			ld.Dwarfemitdebugsections()

		case obj.Hdarwin:
			if ld.Linkmode == ld.LinkExternal {
				ld.Machoemitreloc()
			}
		}
	}

	if ld.Debug['v'] != 0 {
		fmt.Fprintf(&ld.Bso, "%5.2f headr\n", obj.Cputime())
	}
	ld.Bso.Flush()
	ld.Cseek(0)
	switch ld.HEADTYPE {
	default:
	case obj.Hplan9: /* plan9 */
		magic := int32(4*26*26 + 7)

		magic |= 0x00008000                  /* fat header */
		ld.Lputb(uint32(magic))              /* magic */
		ld.Lputb(uint32(ld.Segtext.Filelen)) /* sizes */
		ld.Lputb(uint32(ld.Segdata.Filelen))
		ld.Lputb(uint32(ld.Segdata.Length - ld.Segdata.Filelen))
		ld.Lputb(uint32(ld.Symsize)) /* nsyms */
		vl := ld.Entryvalue()
		ld.Lputb(PADDR(uint32(vl))) /* va of entry */
		ld.Lputb(uint32(ld.Spsize)) /* sp offsets */
		ld.Lputb(uint32(ld.Lcsize)) /* line offsets */
		ld.Vputb(uint64(vl))        /* va of entry */

	case obj.Hdarwin:
		ld.Asmbmacho()

	case obj.Hlinux,
		obj.Hfreebsd,
		obj.Hnetbsd,
		obj.Hopenbsd,
		obj.Hdragonfly,
		obj.Hsolaris,
		obj.Hnacl:
		ld.Asmbelf(symo)

	case obj.Hwindows:
		ld.Asmbpe()
	}

	ld.Cflush()
}
Example #12
0
File: asm.go Project: SpiderOak/go
func asmb(ctxt *ld.Link) {
	if ctxt.Debugvlog != 0 {
		fmt.Fprintf(ctxt.Bso, "%5.2f asmb\n", obj.Cputime())
	}
	ctxt.Bso.Flush()

	if ld.Iself {
		ld.Asmbelfsetup(ctxt)
	}

	sect := ld.Segtext.Sect
	ld.Cseek(int64(sect.Vaddr - ld.Segtext.Vaddr + ld.Segtext.Fileoff))
	// 0xCC is INT $3 - breakpoint instruction
	ld.CodeblkPad(ctxt, int64(sect.Vaddr), int64(sect.Length), []byte{0xCC})
	for sect = sect.Next; sect != nil; sect = sect.Next {
		ld.Cseek(int64(sect.Vaddr - ld.Segtext.Vaddr + ld.Segtext.Fileoff))
		ld.Datblk(ctxt, int64(sect.Vaddr), int64(sect.Length))
	}

	if ld.Segrodata.Filelen > 0 {
		if ctxt.Debugvlog != 0 {
			fmt.Fprintf(ctxt.Bso, "%5.2f rodatblk\n", obj.Cputime())
		}
		ctxt.Bso.Flush()

		ld.Cseek(int64(ld.Segrodata.Fileoff))
		ld.Datblk(ctxt, int64(ld.Segrodata.Vaddr), int64(ld.Segrodata.Filelen))
	}

	if ctxt.Debugvlog != 0 {
		fmt.Fprintf(ctxt.Bso, "%5.2f datblk\n", obj.Cputime())
	}
	ctxt.Bso.Flush()

	ld.Cseek(int64(ld.Segdata.Fileoff))
	ld.Datblk(ctxt, int64(ld.Segdata.Vaddr), int64(ld.Segdata.Filelen))

	ld.Cseek(int64(ld.Segdwarf.Fileoff))
	ld.Dwarfblk(ctxt, int64(ld.Segdwarf.Vaddr), int64(ld.Segdwarf.Filelen))

	machlink := uint32(0)
	if ld.HEADTYPE == obj.Hdarwin {
		machlink = uint32(ld.Domacholink(ctxt))
	}

	ld.Symsize = 0
	ld.Spsize = 0
	ld.Lcsize = 0
	symo := uint32(0)
	if !*ld.FlagS {
		// TODO: rationalize
		if ctxt.Debugvlog != 0 {
			fmt.Fprintf(ctxt.Bso, "%5.2f sym\n", obj.Cputime())
		}
		ctxt.Bso.Flush()
		switch ld.HEADTYPE {
		default:
			if ld.Iself {
				symo = uint32(ld.Segdwarf.Fileoff + ld.Segdwarf.Filelen)
				symo = uint32(ld.Rnd(int64(symo), int64(*ld.FlagRound)))
			}

		case obj.Hplan9:
			symo = uint32(ld.Segdata.Fileoff + ld.Segdata.Filelen)

		case obj.Hdarwin:
			symo = uint32(ld.Segdwarf.Fileoff + uint64(ld.Rnd(int64(ld.Segdwarf.Filelen), int64(*ld.FlagRound))) + uint64(machlink))

		case obj.Hwindows:
			symo = uint32(ld.Segdwarf.Fileoff + ld.Segdwarf.Filelen)
			symo = uint32(ld.Rnd(int64(symo), ld.PEFILEALIGN))
		}

		ld.Cseek(int64(symo))
		switch ld.HEADTYPE {
		default:
			if ld.Iself {
				if ctxt.Debugvlog != 0 {
					fmt.Fprintf(ctxt.Bso, "%5.2f elfsym\n", obj.Cputime())
				}
				ld.Asmelfsym(ctxt)
				ld.Cflush()
				ld.Cwrite(ld.Elfstrdat)

				if ld.Linkmode == ld.LinkExternal {
					ld.Elfemitreloc(ctxt)
				}
			}

		case obj.Hplan9:
			ld.Asmplan9sym(ctxt)
			ld.Cflush()

			sym := ld.Linklookup(ctxt, "pclntab", 0)
			if sym != nil {
				ld.Lcsize = int32(len(sym.P))
				for i := 0; int32(i) < ld.Lcsize; i++ {
					ld.Cput(sym.P[i])
				}

				ld.Cflush()
			}

		case obj.Hwindows:
			if ctxt.Debugvlog != 0 {
				fmt.Fprintf(ctxt.Bso, "%5.2f dwarf\n", obj.Cputime())
			}

		case obj.Hdarwin:
			if ld.Linkmode == ld.LinkExternal {
				ld.Machoemitreloc(ctxt)
			}
		}
	}

	if ctxt.Debugvlog != 0 {
		fmt.Fprintf(ctxt.Bso, "%5.2f headr\n", obj.Cputime())
	}
	ctxt.Bso.Flush()
	ld.Cseek(0)
	switch ld.HEADTYPE {
	default:
	case obj.Hplan9: /* plan9 */
		magic := int32(4*11*11 + 7)

		ld.Lputb(uint32(magic))              /* magic */
		ld.Lputb(uint32(ld.Segtext.Filelen)) /* sizes */
		ld.Lputb(uint32(ld.Segdata.Filelen))
		ld.Lputb(uint32(ld.Segdata.Length - ld.Segdata.Filelen))
		ld.Lputb(uint32(ld.Symsize))          /* nsyms */
		ld.Lputb(uint32(ld.Entryvalue(ctxt))) /* va of entry */
		ld.Lputb(uint32(ld.Spsize))           /* sp offsets */
		ld.Lputb(uint32(ld.Lcsize))           /* line offsets */

	case obj.Hdarwin:
		ld.Asmbmacho(ctxt)

	case obj.Hlinux,
		obj.Hfreebsd,
		obj.Hnetbsd,
		obj.Hopenbsd,
		obj.Hnacl:
		ld.Asmbelf(ctxt, int64(symo))

	case obj.Hwindows:
		ld.Asmbpe(ctxt)
	}

	ld.Cflush()
}
Example #13
0
func ldshlibsyms(shlib string) {
	found := false
	libpath := ""
	for _, libdir := range Ctxt.Libdir {
		libpath = filepath.Join(libdir, shlib)
		if _, err := os.Stat(libpath); err == nil {
			found = true
			break
		}
	}
	if !found {
		Diag("cannot find shared library: %s", shlib)
		return
	}
	for _, processedname := range Ctxt.Shlibs {
		if processedname == libpath {
			return
		}
	}
	if Ctxt.Debugvlog > 1 && Ctxt.Bso != nil {
		fmt.Fprintf(Ctxt.Bso, "%5.2f ldshlibsyms: found library with name %s at %s\n", obj.Cputime(), shlib, libpath)
		Bflush(Ctxt.Bso)
	}

	f, err := elf.Open(libpath)
	if err != nil {
		Diag("cannot open shared library: %s", libpath)
		return
	}
	defer f.Close()
	syms, err := f.DynamicSymbols()
	if err != nil {
		Diag("cannot read symbols from shared library: %s", libpath)
		return
	}
	for _, s := range syms {
		if elf.ST_TYPE(s.Info) == elf.STT_NOTYPE || elf.ST_TYPE(s.Info) == elf.STT_SECTION {
			continue
		}
		if s.Section == elf.SHN_UNDEF {
			continue
		}
		if strings.HasPrefix(s.Name, "_") {
			continue
		}
		lsym := Linklookup(Ctxt, s.Name, 0)
		if lsym.Type != 0 && lsym.Dupok == 0 {
			Diag(
				"Found duplicate symbol %s reading from %s, first found in %s",
				s.Name, shlib, lsym.File)
		}
		lsym.Type = SDYNIMPORT
		lsym.File = libpath
	}

	// We might have overwritten some functions above (this tends to happen for the
	// autogenerated type equality/hashing functions) and we don't want to generated
	// pcln table entries for these any more so unstitch them from the Textp linked
	// list.
	var last *LSym

	for s := Ctxt.Textp; s != nil; s = s.Next {
		if s.Type == SDYNIMPORT {
			continue
		}

		if last == nil {
			Ctxt.Textp = s
		} else {
			last.Next = s
		}
		last = s
	}

	if last == nil {
		Ctxt.Textp = nil
		Ctxt.Etextp = nil
	} else {
		last.Next = nil
		Ctxt.Etextp = last
	}

	Ctxt.Shlibs = append(Ctxt.Shlibs, libpath)
}
Example #14
0
File: pcln.go Project: danny8002/go
func pclntab() {
	funcdata_bytes := int64(0)
	ftab := Linklookup(Ctxt, "runtime.pclntab", 0)
	ftab.Type = obj.SPCLNTAB
	ftab.Reachable = true

	// See golang.org/s/go12symtab for the format. Briefly:
	//	8-byte header
	//	nfunc [thearch.ptrsize bytes]
	//	function table, alternating PC and offset to func struct [each entry thearch.ptrsize bytes]
	//	end PC [thearch.ptrsize bytes]
	//	offset to file table [4 bytes]
	nfunc := int32(0)

	// Find container symbols, mark them with SCONTAINER
	for Ctxt.Cursym = Ctxt.Textp; Ctxt.Cursym != nil; Ctxt.Cursym = Ctxt.Cursym.Next {
		if Ctxt.Cursym.Outer != nil {
			Ctxt.Cursym.Outer.Type |= obj.SCONTAINER
		}
	}

	for Ctxt.Cursym = Ctxt.Textp; Ctxt.Cursym != nil; Ctxt.Cursym = Ctxt.Cursym.Next {
		if container(Ctxt.Cursym) == 0 {
			nfunc++
		}
	}

	pclntabNfunc = nfunc
	Symgrow(Ctxt, ftab, 8+int64(Thearch.Ptrsize)+int64(nfunc)*2*int64(Thearch.Ptrsize)+int64(Thearch.Ptrsize)+4)
	setuint32(Ctxt, ftab, 0, 0xfffffffb)
	setuint8(Ctxt, ftab, 6, uint8(Thearch.Minlc))
	setuint8(Ctxt, ftab, 7, uint8(Thearch.Ptrsize))
	setuintxx(Ctxt, ftab, 8, uint64(nfunc), int64(Thearch.Ptrsize))
	pclntabPclntabOffset = int32(8 + Thearch.Ptrsize)

	nfunc = 0
	var last *LSym
	var end int32
	var funcstart int32
	var i int32
	var it Pciter
	var off int32
	var pcln *Pcln
	for Ctxt.Cursym = Ctxt.Textp; Ctxt.Cursym != nil; Ctxt.Cursym = Ctxt.Cursym.Next {
		last = Ctxt.Cursym
		if container(Ctxt.Cursym) != 0 {
			continue
		}
		pcln = Ctxt.Cursym.Pcln
		if pcln == nil {
			pcln = &pclntab_zpcln
		}

		if pclntabFirstFunc == nil {
			pclntabFirstFunc = Ctxt.Cursym
		}

		funcstart = int32(len(ftab.P))
		funcstart += int32(-len(ftab.P)) & (int32(Thearch.Ptrsize) - 1)

		setaddr(Ctxt, ftab, 8+int64(Thearch.Ptrsize)+int64(nfunc)*2*int64(Thearch.Ptrsize), Ctxt.Cursym)
		setuintxx(Ctxt, ftab, 8+int64(Thearch.Ptrsize)+int64(nfunc)*2*int64(Thearch.Ptrsize)+int64(Thearch.Ptrsize), uint64(funcstart), int64(Thearch.Ptrsize))

		// 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 += 4
		}
		Symgrow(Ctxt, ftab, int64(end))

		// entry uintptr
		off = int32(setaddr(Ctxt, ftab, int64(off), Ctxt.Cursym))

		// name int32
		off = int32(setuint32(Ctxt, ftab, int64(off), uint32(ftabaddstring(ftab, Ctxt.Cursym.Name))))

		// args int32
		// TODO: Move into funcinfo.
		off = int32(setuint32(Ctxt, ftab, int64(off), uint32(Ctxt.Cursym.Args)))

		// frame int32
		// This has been removed (it was never set quite correctly anyway).
		// Nothing should use it.
		// Leave an obviously incorrect value.
		// TODO: Remove entirely.
		off = int32(setuint32(Ctxt, ftab, int64(off), 0x1234567))

		if pcln != &pclntab_zpcln {
			renumberfiles(Ctxt, pcln.File, &pcln.Pcfile)
			if false {
				// Sanity check the new numbering
				for pciterinit(Ctxt, &it, &pcln.Pcfile); it.done == 0; pciternext(&it) {
					if it.value < 1 || it.value > Ctxt.Nhistfile {
						Diag("bad file number in pcfile: %d not in range [1, %d]\n", it.value, Ctxt.Nhistfile)
						errorexit()
					}
				}
			}
		}

		// pcdata
		off = addpctab(ftab, off, &pcln.Pcsp)

		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 = 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 off&int32(Thearch.Ptrsize-1) != 0 {
				off += 4
			}
			for i = 0; i < int32(pcln.Nfuncdata); i++ {
				if pcln.Funcdata[i] == nil {
					setuintxx(Ctxt, ftab, int64(off)+int64(Thearch.Ptrsize)*int64(i), uint64(pcln.Funcdataoff[i]), int64(Thearch.Ptrsize))
				} else {
					// TODO: Dedup.
					funcdata_bytes += pcln.Funcdata[i].Size

					setaddrplus(Ctxt, ftab, int64(off)+int64(Thearch.Ptrsize)*int64(i), pcln.Funcdata[i], pcln.Funcdataoff[i])
				}
			}

			off += int32(pcln.Nfuncdata) * 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)
			errorexit()
		}

		nfunc++
	}

	pclntabLastFunc = last
	// Final entry of table is just end pc.
	setaddrplus(Ctxt, ftab, 8+int64(Thearch.Ptrsize)+int64(nfunc)*2*int64(Thearch.Ptrsize), last, last.Size)

	// Start file table.
	start := int32(len(ftab.P))

	start += int32(-len(ftab.P)) & (int32(Thearch.Ptrsize) - 1)
	pclntabFiletabOffset = start
	setuint32(Ctxt, ftab, 8+int64(Thearch.Ptrsize)+int64(nfunc)*2*int64(Thearch.Ptrsize)+int64(Thearch.Ptrsize), uint32(start))

	Symgrow(Ctxt, ftab, int64(start)+(int64(Ctxt.Nhistfile)+1)*4)
	setuint32(Ctxt, ftab, int64(start), uint32(Ctxt.Nhistfile))
	for s := Ctxt.Filesyms; s != nil; s = s.Next {
		setuint32(Ctxt, ftab, int64(start)+s.Value*4, uint32(ftabaddstring(ftab, s.Name)))
	}

	ftab.Size = int64(len(ftab.P))

	if Debug['v'] != 0 {
		fmt.Fprintf(&Bso, "%5.2f pclntab=%d bytes, funcdata total %d bytes\n", obj.Cputime(), int64(ftab.Size), int64(funcdata_bytes))
	}
}
Example #15
0
/*
 * This is the main entry point for generating dwarf.  After emitting
 * the mandatory debug_abbrev section, it calls writelines() to set up
 * the per-compilation unit part of the DIE tree, while simultaneously
 * emitting the debug_line section.  When the final tree contains
 * forward references, it will write the debug_info section in 2
 * passes.
 *
 */
func dwarfgeneratedebugsyms(ctxt *Link) {
	if *FlagW { // disable dwarf
		return
	}
	if *FlagS && HEADTYPE != obj.Hdarwin {
		return
	}
	if HEADTYPE == obj.Hplan9 {
		return
	}

	if Linkmode == LinkExternal {
		if !Iself && HEADTYPE != obj.Hdarwin {
			return
		}
	}

	if ctxt.Debugvlog != 0 {
		fmt.Fprintf(ctxt.Bso, "%5.2f dwarf\n", obj.Cputime())
	}

	// Forctxt.Diagnostic messages.
	newattr(&dwtypes, dwarf.DW_AT_name, dwarf.DW_CLS_STRING, int64(len("dwtypes")), "dwtypes")

	// Some types that must exist to define other ones.
	newdie(ctxt, &dwtypes, dwarf.DW_ABRV_NULLTYPE, "<unspecified>", 0)

	newdie(ctxt, &dwtypes, dwarf.DW_ABRV_NULLTYPE, "void", 0)
	newdie(ctxt, &dwtypes, dwarf.DW_ABRV_BARE_PTRTYPE, "unsafe.Pointer", 0)

	die := newdie(ctxt, &dwtypes, dwarf.DW_ABRV_BASETYPE, "uintptr", 0) // needed for array size
	newattr(die, dwarf.DW_AT_encoding, dwarf.DW_CLS_CONSTANT, dwarf.DW_ATE_unsigned, 0)
	newattr(die, dwarf.DW_AT_byte_size, dwarf.DW_CLS_CONSTANT, int64(SysArch.PtrSize), 0)
	newattr(die, dwarf.DW_AT_go_kind, dwarf.DW_CLS_CONSTANT, obj.KindUintptr, 0)

	// Prototypes needed for type synthesis.
	prototypedies = map[string]*dwarf.DWDie{
		"type.runtime.stringStructDWARF": nil,
		"type.runtime.slice":             nil,
		"type.runtime.hmap":              nil,
		"type.runtime.bmap":              nil,
		"type.runtime.sudog":             nil,
		"type.runtime.waitq":             nil,
		"type.runtime.hchan":             nil,
	}

	// Needed by the prettyprinter code for interface inspection.
	defgotype(ctxt, lookup_or_diag(ctxt, "type.runtime._type"))

	defgotype(ctxt, lookup_or_diag(ctxt, "type.runtime.interfacetype"))
	defgotype(ctxt, lookup_or_diag(ctxt, "type.runtime.itab"))

	genasmsym(ctxt, defdwsymb)

	syms := writeabbrev(ctxt, nil)
	syms, funcs := writelines(ctxt, syms)
	syms = writeframes(ctxt, syms)

	synthesizestringtypes(ctxt, dwtypes.Child)
	synthesizeslicetypes(ctxt, dwtypes.Child)
	synthesizemaptypes(ctxt, dwtypes.Child)
	synthesizechantypes(ctxt, dwtypes.Child)

	reversetree(&dwroot.Child)
	reversetree(&dwtypes.Child)
	reversetree(&dwglobals.Child)

	movetomodule(&dwtypes)
	movetomodule(&dwglobals)

	// Need to reorder symbols so SDWARFINFO is after all SDWARFSECT
	// (but we need to generate dies before writepub)
	infosyms := writeinfo(ctxt, nil, funcs)

	syms = writepub(ctxt, ".debug_pubnames", ispubname, syms)
	syms = writepub(ctxt, ".debug_pubtypes", ispubtype, syms)
	syms = writearanges(ctxt, syms)
	syms = writegdbscript(ctxt, syms)
	syms = append(syms, infosyms...)
	dwarfp = syms
}
Example #16
0
File: asm.go Project: hurkgu/go
func asmb(ctxt *ld.Link) {
	if ctxt.Debugvlog != 0 {
		ctxt.Logf("%5.2f asmb\n", obj.Cputime())
	}

	if ld.Iself {
		ld.Asmbelfsetup(ctxt)
	}

	sect := ld.Segtext.Sect
	ld.Cseek(int64(sect.Vaddr - ld.Segtext.Vaddr + ld.Segtext.Fileoff))
	ld.Codeblk(ctxt, 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(ctxt, int64(sect.Vaddr), int64(sect.Length))
	}

	if ld.Segrodata.Filelen > 0 {
		if ctxt.Debugvlog != 0 {
			ctxt.Logf("%5.2f rodatblk\n", obj.Cputime())
		}

		ld.Cseek(int64(ld.Segrodata.Fileoff))
		ld.Datblk(ctxt, int64(ld.Segrodata.Vaddr), int64(ld.Segrodata.Filelen))
	}

	if ctxt.Debugvlog != 0 {
		ctxt.Logf("%5.2f datblk\n", obj.Cputime())
	}

	ld.Cseek(int64(ld.Segdata.Fileoff))
	ld.Datblk(ctxt, int64(ld.Segdata.Vaddr), int64(ld.Segdata.Filelen))

	ld.Cseek(int64(ld.Segdwarf.Fileoff))
	ld.Dwarfblk(ctxt, int64(ld.Segdwarf.Vaddr), int64(ld.Segdwarf.Filelen))

	/* output symbol table */
	ld.Symsize = 0

	ld.Lcsize = 0
	symo := uint32(0)
	if !*ld.FlagS {
		if !ld.Iself {
			ctxt.Diag("unsupported executable format")
		}
		if ctxt.Debugvlog != 0 {
			ctxt.Logf("%5.2f sym\n", obj.Cputime())
		}
		symo = uint32(ld.Segdwarf.Fileoff + ld.Segdwarf.Filelen)
		symo = uint32(ld.Rnd(int64(symo), int64(*ld.FlagRound)))

		ld.Cseek(int64(symo))
		if ctxt.Debugvlog != 0 {
			ctxt.Logf("%5.2f elfsym\n", obj.Cputime())
		}
		ld.Asmelfsym(ctxt)
		ld.Cflush()
		ld.Cwrite(ld.Elfstrdat)

		if ctxt.Debugvlog != 0 {
			ctxt.Logf("%5.2f dwarf\n", obj.Cputime())
		}

		if ld.Linkmode == ld.LinkExternal {
			ld.Elfemitreloc(ctxt)
		}
	}

	ctxt.Cursym = nil
	if ctxt.Debugvlog != 0 {
		ctxt.Logf("%5.2f header\n", obj.Cputime())
	}
	ld.Cseek(0)
	switch ld.HEADTYPE {
	default:
		ctxt.Diag("unsupported operating system")
	case obj.Hlinux:
		ld.Asmbelf(ctxt, int64(symo))
	}

	ld.Cflush()
	if *ld.FlagC {
		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))
	}
}
Example #17
0
// deadcode marks all reachable symbols.
//
// The basis of the dead code elimination is a flood fill of symbols,
// following their relocations, beginning at INITENTRY.
//
// This flood fill is wrapped in logic for pruning unused methods.
// All methods are mentioned by relocations on their receiver's *rtype.
// These relocations are specially defined as R_METHODOFF by the compiler
// so we can detect and manipulated them here.
//
// There are three ways a method of a reachable type can be invoked:
//
//	1. direct call
//	2. through a reachable interface type
//	3. reflect.Value.Call, .Method, or reflect.Method.Func
//
// The first case is handled by the flood fill, a directly called method
// is marked as reachable.
//
// The second case is handled by decomposing all reachable interface
// types into method signatures. Each encountered method is compared
// against the interface method signatures, if it matches it is marked
// as reachable. This is extremely conservative, but easy and correct.
//
// The third case is handled by looking to see if any of:
//	- reflect.Value.Call is reachable
//	- reflect.Value.Method is reachable
// 	- reflect.Type.Method or MethodByName is called.
// If any of these happen, all bets are off and all exported methods
// of reachable types are marked reachable.
//
// Any unreached text symbols are removed from ctxt.Textp.
func deadcode(ctxt *Link) {
	if Debug['v'] != 0 {
		fmt.Fprintf(ctxt.Bso, "%5.2f deadcode\n", obj.Cputime())
	}

	d := &deadcodepass{
		ctxt:        ctxt,
		ifaceMethod: make(map[methodsig]bool),
	}

	// First, flood fill any symbols directly reachable in the call
	// graph from INITENTRY. Ignore all methods not directly called.
	d.init()
	d.flood()

	callSym := Linkrlookup(ctxt, "reflect.Value.Call", 0)
	methSym := Linkrlookup(ctxt, "reflect.Value.Method", 0)
	reflectSeen := false

	if DynlinkingGo() {
		// Exported methods may satisfy interfaces we don't know
		// about yet when dynamically linking.
		reflectSeen = true
	}

	for {
		if !reflectSeen {
			if d.reflectMethod || (callSym != nil && callSym.Attr.Reachable()) || (methSym != nil && methSym.Attr.Reachable()) {
				// Methods might be called via reflection. Give up on
				// static analysis, mark all exported methods of
				// all reachable types as reachable.
				reflectSeen = true
			}
		}

		// Mark all methods that could satisfy a discovered
		// interface as reachable. We recheck old marked interfaces
		// as new types (with new methods) may have been discovered
		// in the last pass.
		var rem []methodref
		for _, m := range d.markableMethods {
			if (reflectSeen && m.isExported()) || d.ifaceMethod[m.m] {
				d.markMethod(m)
			} else {
				rem = append(rem, m)
			}
		}
		d.markableMethods = rem

		if len(d.markQueue) == 0 {
			// No new work was discovered. Done.
			break
		}
		d.flood()
	}

	// Remove all remaining unreached R_METHODOFF relocations.
	for _, m := range d.markableMethods {
		for _, r := range m.r {
			d.cleanupReloc(r)
		}
	}

	if Buildmode != BuildmodeShared {
		// Keep a typelink or itablink if the symbol it points at is being kept.
		// (When BuildmodeShared, always keep typelinks and itablinks.)
		for _, s := range ctxt.Allsym {
			if strings.HasPrefix(s.Name, "go.typelink.") ||
				strings.HasPrefix(s.Name, "go.itablink.") {
				s.Attr.Set(AttrReachable, len(s.R) == 1 && s.R[0].Sym.Attr.Reachable())
			}
		}
	}

	// Remove dead text but keep file information (z symbols).
	textp := make([]*LSym, 0, len(ctxt.Textp))
	for _, s := range ctxt.Textp {
		if s.Attr.Reachable() {
			textp = append(textp, s)
		}
	}
	ctxt.Textp = textp
}
Example #18
0
func dodata() {
	if Debug['v'] != 0 {
		fmt.Fprintf(&Bso, "%5.2f dodata\n", obj.Cputime())
	}
	Bflush(&Bso)

	var last *LSym
	datap = nil

	for s := Ctxt.Allsym; s != nil; s = s.Allsym {
		if !s.Reachable || s.Special != 0 {
			continue
		}
		if STEXT < s.Type && s.Type < SXREF {
			if s.Onlist != 0 {
				log.Fatalf("symbol %s listed multiple times", s.Name)
			}
			s.Onlist = 1
			if last == nil {
				datap = s
			} else {
				last.Next = s
			}
			s.Next = nil
			last = s
		}
	}

	for s := datap; s != nil; s = s.Next {
		if int64(len(s.P)) > s.Size {
			Diag("%s: initialize bounds (%d < %d)", s.Name, int64(s.Size), len(s.P))
		}
	}

	/*
	 * now that we have the datap list, but before we start
	 * to assign addresses, record all the necessary
	 * dynamic relocations.  these will grow the relocation
	 * symbol, which is itself data.
	 *
	 * on darwin, we need the symbol table numbers for dynreloc.
	 */
	if HEADTYPE == Hdarwin {
		machosymorder()
	}
	dynreloc()

	/* some symbols may no longer belong in datap (Mach-O) */
	var l **LSym
	var s *LSym
	for l = &datap; ; {
		s = *l
		if s == nil {
			break
		}

		if s.Type <= STEXT || SXREF <= s.Type {
			*l = s.Next
		} else {
			l = &s.Next
		}
	}

	*l = nil

	datap = listsort(datap, datcmp, listnextp)

	/*
	 * allocate sections.  list is sorted by type,
	 * so we can just walk it for each piece we want to emit.
	 * segdata is processed before segtext, because we need
	 * to see all symbols in the .data and .bss sections in order
	 * to generate garbage collection information.
	 */

	/* begin segdata */

	/* skip symbols belonging to segtext */
	s = datap

	for ; s != nil && s.Type < SELFSECT; s = s.Next {
	}

	/* writable ELF sections */
	datsize := int64(0)

	var sect *Section
	for ; s != nil && s.Type < SELFGOT; s = s.Next {
		sect = addsection(&Segdata, s.Name, 06)
		sect.Align = symalign(s)
		datsize = Rnd(datsize, int64(sect.Align))
		sect.Vaddr = uint64(datsize)
		s.Sect = sect
		s.Type = SDATA
		s.Value = int64(uint64(datsize) - sect.Vaddr)
		growdatsize(&datsize, s)
		sect.Length = uint64(datsize) - sect.Vaddr
	}

	/* .got (and .toc on ppc64) */
	if s.Type == SELFGOT {
		sect := addsection(&Segdata, ".got", 06)
		sect.Align = maxalign(s, SELFGOT)
		datsize = Rnd(datsize, int64(sect.Align))
		sect.Vaddr = uint64(datsize)
		var toc *LSym
		for ; s != nil && s.Type == SELFGOT; s = s.Next {
			datsize = aligndatsize(datsize, s)
			s.Sect = sect
			s.Type = SDATA
			s.Value = int64(uint64(datsize) - sect.Vaddr)

			// Resolve .TOC. symbol for this object file (ppc64)
			toc = Linkrlookup(Ctxt, ".TOC.", int(s.Version))

			if toc != nil {
				toc.Sect = sect
				toc.Outer = s
				toc.Sub = s.Sub
				s.Sub = toc

				toc.Value = 0x8000
			}

			growdatsize(&datsize, s)
		}

		sect.Length = uint64(datsize) - sect.Vaddr
	}

	/* pointer-free data */
	sect = addsection(&Segdata, ".noptrdata", 06)

	sect.Align = maxalign(s, SINITARR-1)
	datsize = Rnd(datsize, int64(sect.Align))
	sect.Vaddr = uint64(datsize)
	Linklookup(Ctxt, "runtime.noptrdata", 0).Sect = sect
	Linklookup(Ctxt, "runtime.enoptrdata", 0).Sect = sect
	for ; s != nil && s.Type < SINITARR; s = s.Next {
		datsize = aligndatsize(datsize, s)
		s.Sect = sect
		s.Type = SDATA
		s.Value = int64(uint64(datsize) - sect.Vaddr)
		growdatsize(&datsize, s)
	}

	sect.Length = uint64(datsize) - sect.Vaddr

	hasinitarr := Linkshared

	/* shared library initializer */
	switch Buildmode {
	case BuildmodeCArchive, BuildmodeCShared, BuildmodeShared:
		hasinitarr = true
	}

	if hasinitarr {
		sect := addsection(&Segdata, ".init_array", 06)
		sect.Align = maxalign(s, SINITARR)
		datsize = Rnd(datsize, int64(sect.Align))
		sect.Vaddr = uint64(datsize)
		for ; s != nil && s.Type == SINITARR; s = s.Next {
			datsize = aligndatsize(datsize, s)
			s.Sect = sect
			s.Value = int64(uint64(datsize) - sect.Vaddr)
			growdatsize(&datsize, s)
		}

		sect.Length = uint64(datsize) - sect.Vaddr
	}

	/* data */
	sect = addsection(&Segdata, ".data", 06)

	sect.Align = maxalign(s, SBSS-1)
	datsize = Rnd(datsize, int64(sect.Align))
	sect.Vaddr = uint64(datsize)
	Linklookup(Ctxt, "runtime.data", 0).Sect = sect
	Linklookup(Ctxt, "runtime.edata", 0).Sect = sect
	gcdata := Linklookup(Ctxt, "runtime.gcdata", 0)
	var gen ProgGen
	proggeninit(&gen, gcdata)
	for ; s != nil && s.Type < SBSS; s = s.Next {
		if s.Type == SINITARR {
			Ctxt.Cursym = s
			Diag("unexpected symbol type %d", s.Type)
		}

		s.Sect = sect
		s.Type = SDATA
		datsize = aligndatsize(datsize, s)
		s.Value = int64(uint64(datsize) - sect.Vaddr)
		proggenaddsym(&gen, s) // gc
		growdatsize(&datsize, s)
	}

	sect.Length = uint64(datsize) - sect.Vaddr
	proggenfini(&gen, int64(sect.Length)) // gc

	/* bss */
	sect = addsection(&Segdata, ".bss", 06)

	sect.Align = maxalign(s, SNOPTRBSS-1)
	datsize = Rnd(datsize, int64(sect.Align))
	sect.Vaddr = uint64(datsize)
	Linklookup(Ctxt, "runtime.bss", 0).Sect = sect
	Linklookup(Ctxt, "runtime.ebss", 0).Sect = sect
	gcbss := Linklookup(Ctxt, "runtime.gcbss", 0)
	proggeninit(&gen, gcbss)
	for ; s != nil && s.Type < SNOPTRBSS; s = s.Next {
		s.Sect = sect
		datsize = aligndatsize(datsize, s)
		s.Value = int64(uint64(datsize) - sect.Vaddr)
		proggenaddsym(&gen, s) // gc
		growdatsize(&datsize, s)
	}

	sect.Length = uint64(datsize) - sect.Vaddr
	proggenfini(&gen, int64(sect.Length)) // gc

	/* pointer-free bss */
	sect = addsection(&Segdata, ".noptrbss", 06)

	sect.Align = maxalign(s, SNOPTRBSS)
	datsize = Rnd(datsize, int64(sect.Align))
	sect.Vaddr = uint64(datsize)
	Linklookup(Ctxt, "runtime.noptrbss", 0).Sect = sect
	Linklookup(Ctxt, "runtime.enoptrbss", 0).Sect = sect
	for ; s != nil && s.Type == SNOPTRBSS; s = s.Next {
		datsize = aligndatsize(datsize, s)
		s.Sect = sect
		s.Value = int64(uint64(datsize) - sect.Vaddr)
		growdatsize(&datsize, s)
	}

	sect.Length = uint64(datsize) - sect.Vaddr
	Linklookup(Ctxt, "runtime.end", 0).Sect = sect

	// 6g uses 4-byte relocation offsets, so the entire segment must fit in 32 bits.
	if datsize != int64(uint32(datsize)) {
		Diag("data or bss segment too large")
	}

	if Iself && Linkmode == LinkExternal && s != nil && s.Type == STLSBSS && HEADTYPE != Hopenbsd {
		sect := addsection(&Segdata, ".tbss", 06)
		sect.Align = int32(Thearch.Ptrsize)
		sect.Vaddr = 0
		datsize = 0
		for ; s != nil && s.Type == STLSBSS; s = s.Next {
			datsize = aligndatsize(datsize, s)
			s.Sect = sect
			s.Value = int64(uint64(datsize) - sect.Vaddr)
			growdatsize(&datsize, s)
		}

		sect.Length = uint64(datsize)
	} else {
		// Might be internal linking but still using cgo.
		// In that case, the only possible STLSBSS symbol is runtime.tlsg.
		// Give it offset 0, because it's the only thing here.
		if s != nil && s.Type == STLSBSS && s.Name == "runtime.tlsg" {
			s.Value = 0
			s = s.Next
		}
	}

	if s != nil {
		Ctxt.Cursym = nil
		Diag("unexpected symbol type %d for %s", s.Type, s.Name)
	}

	/*
	 * We finished data, begin read-only data.
	 * Not all systems support a separate read-only non-executable data section.
	 * ELF systems do.
	 * OS X and Plan 9 do not.
	 * Windows PE may, but if so we have not implemented it.
	 * And if we're using external linking mode, the point is moot,
	 * since it's not our decision; that code expects the sections in
	 * segtext.
	 */
	var segro *Segment
	if Iself && Linkmode == LinkInternal {
		segro = &Segrodata
	} else {
		segro = &Segtext
	}

	s = datap

	datsize = 0

	/* read-only executable ELF, Mach-O sections */
	for ; s != nil && s.Type < STYPE; s = s.Next {
		sect = addsection(&Segtext, s.Name, 04)
		sect.Align = symalign(s)
		datsize = Rnd(datsize, int64(sect.Align))
		sect.Vaddr = uint64(datsize)
		s.Sect = sect
		s.Type = SRODATA
		s.Value = int64(uint64(datsize) - sect.Vaddr)
		growdatsize(&datsize, s)
		sect.Length = uint64(datsize) - sect.Vaddr
	}

	/* read-only data */
	sect = addsection(segro, ".rodata", 04)

	sect.Align = maxalign(s, STYPELINK-1)
	datsize = Rnd(datsize, int64(sect.Align))
	sect.Vaddr = 0
	Linklookup(Ctxt, "runtime.rodata", 0).Sect = sect
	Linklookup(Ctxt, "runtime.erodata", 0).Sect = sect
	for ; s != nil && s.Type < STYPELINK; s = s.Next {
		datsize = aligndatsize(datsize, s)
		s.Sect = sect
		s.Type = SRODATA
		s.Value = int64(uint64(datsize) - sect.Vaddr)
		growdatsize(&datsize, s)
	}

	sect.Length = uint64(datsize) - sect.Vaddr

	/* typelink */
	sect = addsection(segro, ".typelink", 04)

	sect.Align = maxalign(s, STYPELINK)
	datsize = Rnd(datsize, int64(sect.Align))
	sect.Vaddr = uint64(datsize)
	Linklookup(Ctxt, "runtime.typelink", 0).Sect = sect
	Linklookup(Ctxt, "runtime.etypelink", 0).Sect = sect
	for ; s != nil && s.Type == STYPELINK; s = s.Next {
		datsize = aligndatsize(datsize, s)
		s.Sect = sect
		s.Type = SRODATA
		s.Value = int64(uint64(datsize) - sect.Vaddr)
		growdatsize(&datsize, s)
	}

	sect.Length = uint64(datsize) - sect.Vaddr

	/* gosymtab */
	sect = addsection(segro, ".gosymtab", 04)

	sect.Align = maxalign(s, SPCLNTAB-1)
	datsize = Rnd(datsize, int64(sect.Align))
	sect.Vaddr = uint64(datsize)
	Linklookup(Ctxt, "runtime.symtab", 0).Sect = sect
	Linklookup(Ctxt, "runtime.esymtab", 0).Sect = sect
	for ; s != nil && s.Type < SPCLNTAB; s = s.Next {
		datsize = aligndatsize(datsize, s)
		s.Sect = sect
		s.Type = SRODATA
		s.Value = int64(uint64(datsize) - sect.Vaddr)
		growdatsize(&datsize, s)
	}

	sect.Length = uint64(datsize) - sect.Vaddr

	/* gopclntab */
	sect = addsection(segro, ".gopclntab", 04)

	sect.Align = maxalign(s, SELFROSECT-1)
	datsize = Rnd(datsize, int64(sect.Align))
	sect.Vaddr = uint64(datsize)
	Linklookup(Ctxt, "runtime.pclntab", 0).Sect = sect
	Linklookup(Ctxt, "runtime.epclntab", 0).Sect = sect
	for ; s != nil && s.Type < SELFROSECT; s = s.Next {
		datsize = aligndatsize(datsize, s)
		s.Sect = sect
		s.Type = SRODATA
		s.Value = int64(uint64(datsize) - sect.Vaddr)
		growdatsize(&datsize, s)
	}

	sect.Length = uint64(datsize) - sect.Vaddr

	/* read-only ELF, Mach-O sections */
	for ; s != nil && s.Type < SELFSECT; s = s.Next {
		sect = addsection(segro, s.Name, 04)
		sect.Align = symalign(s)
		datsize = Rnd(datsize, int64(sect.Align))
		sect.Vaddr = uint64(datsize)
		s.Sect = sect
		s.Type = SRODATA
		s.Value = int64(uint64(datsize) - sect.Vaddr)
		growdatsize(&datsize, s)
		sect.Length = uint64(datsize) - sect.Vaddr
	}

	// 6g uses 4-byte relocation offsets, so the entire segment must fit in 32 bits.
	if datsize != int64(uint32(datsize)) {
		Diag("read-only data segment too large")
	}

	/* number the sections */
	n := int32(1)

	for sect := Segtext.Sect; sect != nil; sect = sect.Next {
		sect.Extnum = int16(n)
		n++
	}
	for sect := Segrodata.Sect; sect != nil; sect = sect.Next {
		sect.Extnum = int16(n)
		n++
	}
	for sect := Segdata.Sect; sect != nil; sect = sect.Next {
		sect.Extnum = int16(n)
		n++
	}
}
Example #19
0
File: asm.go Project: hurkgu/go
func asmb(ctxt *ld.Link) {
	if ctxt.Debugvlog != 0 {
		ctxt.Logf("%5.2f asmb\n", obj.Cputime())
	}

	if ld.Iself {
		ld.Asmbelfsetup(ctxt)
	}

	sect := ld.Segtext.Sect
	ld.Cseek(int64(sect.Vaddr - ld.Segtext.Vaddr + ld.Segtext.Fileoff))
	ld.Codeblk(ctxt, 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(ctxt, int64(sect.Vaddr), int64(sect.Length))
	}

	if ld.Segrodata.Filelen > 0 {
		if ctxt.Debugvlog != 0 {
			ctxt.Logf("%5.2f rodatblk\n", obj.Cputime())
		}

		ld.Cseek(int64(ld.Segrodata.Fileoff))
		ld.Datblk(ctxt, int64(ld.Segrodata.Vaddr), int64(ld.Segrodata.Filelen))
	}

	if ctxt.Debugvlog != 0 {
		ctxt.Logf("%5.2f datblk\n", obj.Cputime())
	}

	ld.Cseek(int64(ld.Segdata.Fileoff))
	ld.Datblk(ctxt, int64(ld.Segdata.Vaddr), int64(ld.Segdata.Filelen))

	ld.Cseek(int64(ld.Segdwarf.Fileoff))
	ld.Dwarfblk(ctxt, int64(ld.Segdwarf.Vaddr), int64(ld.Segdwarf.Filelen))

	/* output symbol table */
	ld.Symsize = 0

	ld.Lcsize = 0
	symo := uint32(0)
	if !*ld.FlagS {
		// TODO: rationalize
		if ctxt.Debugvlog != 0 {
			ctxt.Logf("%5.2f sym\n", obj.Cputime())
		}
		switch ld.HEADTYPE {
		default:
			if ld.Iself {
				symo = uint32(ld.Segdwarf.Fileoff + ld.Segdwarf.Filelen)
				symo = uint32(ld.Rnd(int64(symo), int64(*ld.FlagRound)))
			}

		case obj.Hplan9:
			symo = uint32(ld.Segdata.Fileoff + ld.Segdata.Filelen)
		}

		ld.Cseek(int64(symo))
		switch ld.HEADTYPE {
		default:
			if ld.Iself {
				if ctxt.Debugvlog != 0 {
					ctxt.Logf("%5.2f elfsym\n", obj.Cputime())
				}
				ld.Asmelfsym(ctxt)
				ld.Cflush()
				ld.Cwrite(ld.Elfstrdat)

				if ld.Linkmode == ld.LinkExternal {
					ld.Elfemitreloc(ctxt)
				}
			}

		case obj.Hplan9:
			ld.Asmplan9sym(ctxt)
			ld.Cflush()

			sym := ld.Linklookup(ctxt, "pclntab", 0)
			if sym != nil {
				ld.Lcsize = int32(len(sym.P))
				for i := 0; int32(i) < ld.Lcsize; i++ {
					ld.Cput(sym.P[i])
				}

				ld.Cflush()
			}
		}
	}

	ctxt.Cursym = nil
	if ctxt.Debugvlog != 0 {
		ctxt.Logf("%5.2f header\n", obj.Cputime())
	}
	ld.Cseek(0)
	switch ld.HEADTYPE {
	default:
	case obj.Hplan9: /* plan 9 */
		magic := uint32(4*18*18 + 7)
		if ld.SysArch == sys.ArchMIPS64LE {
			magic = uint32(4*26*26 + 7)
		}
		ld.Thearch.Lput(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(ctxt))) /* 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(ctxt, int64(symo))
	}

	ld.Cflush()
	if *ld.FlagC {
		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))
	}
}
Example #20
0
func genasmsym(put func(*LSym, string, int, int64, int64, int, *LSym)) {
	// These symbols won't show up in the first loop below because we
	// skip STEXT symbols. Normal STEXT symbols are emitted by walking textp.
	s := Linklookup(Ctxt, "runtime.text", 0)

	if s.Type == obj.STEXT {
		put(s, s.Name, 'T', s.Value, s.Size, int(s.Version), nil)
	}
	s = Linklookup(Ctxt, "runtime.etext", 0)
	if s.Type == obj.STEXT {
		put(s, s.Name, 'T', s.Value, s.Size, int(s.Version), nil)
	}

	for s := Ctxt.Allsym; s != nil; s = s.Allsym {
		if s.Hide != 0 || (s.Name[0] == '.' && s.Version == 0 && s.Name != ".rathole") {
			continue
		}
		switch s.Type & obj.SMASK {
		case obj.SCONST,
			obj.SRODATA,
			obj.SSYMTAB,
			obj.SPCLNTAB,
			obj.SINITARR,
			obj.SDATA,
			obj.SNOPTRDATA,
			obj.SELFROSECT,
			obj.SMACHOGOT,
			obj.STYPE,
			obj.SSTRING,
			obj.SGOSTRING,
			obj.SGOFUNC,
			obj.SWINDOWS:
			if !s.Reachable {
				continue
			}
			put(s, s.Name, 'D', Symaddr(s), s.Size, int(s.Version), s.Gotype)

		case obj.SBSS, obj.SNOPTRBSS:
			if !s.Reachable {
				continue
			}
			if len(s.P) > 0 {
				Diag("%s should not be bss (size=%d type=%d special=%d)", s.Name, int(len(s.P)), s.Type, s.Special)
			}
			put(s, s.Name, 'B', Symaddr(s), s.Size, int(s.Version), s.Gotype)

		case obj.SFILE:
			put(nil, s.Name, 'f', s.Value, 0, int(s.Version), nil)

		case obj.SHOSTOBJ:
			if HEADTYPE == obj.Hwindows || Iself {
				put(s, s.Name, 'U', s.Value, 0, int(s.Version), nil)
			}

		case obj.SDYNIMPORT:
			if !s.Reachable {
				continue
			}
			put(s, s.Extname, 'U', 0, 0, int(s.Version), nil)

		case obj.STLSBSS:
			if Linkmode == LinkExternal && HEADTYPE != obj.Hopenbsd {
				var type_ int
				if goos == "android" {
					type_ = 'B'
				} else {
					type_ = 't'
				}
				put(s, s.Name, type_, Symaddr(s), s.Size, int(s.Version), s.Gotype)
			}
		}
	}

	var a *Auto
	var off int32
	for s := Ctxt.Textp; s != nil; s = s.Next {
		put(s, s.Name, 'T', s.Value, s.Size, int(s.Version), s.Gotype)

		// NOTE(ality): acid can't produce a stack trace without .frame symbols
		put(nil, ".frame", 'm', int64(s.Locals)+int64(Thearch.Ptrsize), 0, 0, nil)

		for a = s.Autom; a != nil; a = a.Link {
			// Emit a or p according to actual offset, even if label is wrong.
			// This avoids negative offsets, which cannot be encoded.
			if a.Name != obj.A_AUTO && a.Name != obj.A_PARAM {
				continue
			}

			// compute offset relative to FP
			if a.Name == obj.A_PARAM {
				off = a.Aoffset
			} else {
				off = a.Aoffset - int32(Thearch.Ptrsize)
			}

			// FP
			if off >= 0 {
				put(nil, a.Asym.Name, 'p', int64(off), 0, 0, a.Gotype)
				continue
			}

			// SP
			if off <= int32(-Thearch.Ptrsize) {
				put(nil, a.Asym.Name, 'a', -(int64(off) + int64(Thearch.Ptrsize)), 0, 0, a.Gotype)
				continue
			}
		}
	}

	// Otherwise, off is addressing the saved program counter.
	// Something underhanded is going on. Say nothing.
	if Debug['v'] != 0 || Debug['n'] != 0 {
		fmt.Fprintf(&Bso, "%5.2f symsize = %d\n", obj.Cputime(), uint32(Symsize))
	}
	Bso.Flush()
}
Example #21
0
File: asm.go Project: Mokolea/go
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))

	ld.Cseek(int64(ld.Segdwarf.Fileoff))
	ld.Dwarfblk(int64(ld.Segdwarf.Vaddr), int64(ld.Segdwarf.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.Segdwarf.Fileoff + ld.Segdwarf.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.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(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 */
		ld.Thearch.Lput(0x647)                      /* 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))
	}
}
Example #22
0
func objfile(lib *Library) {
	pkg := pathtoprefix(lib.Pkg)

	if Debug['v'] > 1 {
		fmt.Fprintf(&Bso, "%5.2f ldobj: %s (%s)\n", obj.Cputime(), lib.File, pkg)
	}
	Bso.Flush()
	var err error
	var f *obj.Biobuf
	f, err = obj.Bopenr(lib.File)
	if err != nil {
		Exitf("cannot open file %s: %v", lib.File, err)
	}

	magbuf := make([]byte, len(ARMAG))
	if obj.Bread(f, magbuf) != len(magbuf) || !strings.HasPrefix(string(magbuf), ARMAG) {
		/* load it as a regular file */
		l := obj.Bseek(f, 0, 2)

		obj.Bseek(f, 0, 0)
		ldobj(f, pkg, l, lib.File, lib.File, FileObj)
		obj.Bterm(f)

		return
	}

	/* skip over optional __.GOSYMDEF and process __.PKGDEF */
	off := obj.Boffset(f)

	var arhdr ArHdr
	l := nextar(f, off, &arhdr)
	var pname string
	if l <= 0 {
		Diag("%s: short read on archive file symbol header", lib.File)
		goto out
	}

	if strings.HasPrefix(arhdr.name, symname) {
		off += l
		l = nextar(f, off, &arhdr)
		if l <= 0 {
			Diag("%s: short read on archive file symbol header", lib.File)
			goto out
		}
	}

	if !strings.HasPrefix(arhdr.name, pkgname) {
		Diag("%s: cannot find package header", lib.File)
		goto out
	}

	if Buildmode == BuildmodeShared {
		before := obj.Boffset(f)
		pkgdefBytes := make([]byte, atolwhex(arhdr.size))
		obj.Bread(f, pkgdefBytes)
		hash := sha1.Sum(pkgdefBytes)
		lib.hash = hash[:]
		obj.Bseek(f, before, 0)
	}

	off += l

	if Debug['u'] != 0 {
		ldpkg(f, pkg, atolwhex(arhdr.size), lib.File, Pkgdef)
	}

	/*
	 * load all the object files from the archive now.
	 * this gives us sequential file access and keeps us
	 * from needing to come back later to pick up more
	 * objects.  it breaks the usual C archive model, but
	 * this is Go, not C.  the common case in Go is that
	 * we need to load all the objects, and then we throw away
	 * the individual symbols that are unused.
	 *
	 * loading every object will also make it possible to
	 * load foreign objects not referenced by __.GOSYMDEF.
	 */
	for {
		l = nextar(f, off, &arhdr)
		if l == 0 {
			break
		}
		if l < 0 {
			Exitf("%s: malformed archive", lib.File)
		}

		off += l

		pname = fmt.Sprintf("%s(%s)", lib.File, arhdr.name)
		l = atolwhex(arhdr.size)
		ldobj(f, pkg, l, pname, lib.File, ArchiveObj)
	}

out:
	obj.Bterm(f)
}
Example #23
0
func ldshlibsyms(shlib string) {
	found := false
	libpath := ""
	for _, libdir := range Ctxt.Libdir {
		libpath = filepath.Join(libdir, shlib)
		if _, err := os.Stat(libpath); err == nil {
			found = true
			break
		}
	}
	if !found {
		Diag("cannot find shared library: %s", shlib)
		return
	}
	for _, processedlib := range Ctxt.Shlibs {
		if processedlib.Path == libpath {
			return
		}
	}
	if Ctxt.Debugvlog > 1 && Ctxt.Bso != nil {
		fmt.Fprintf(Ctxt.Bso, "%5.2f ldshlibsyms: found library with name %s at %s\n", obj.Cputime(), shlib, libpath)
		Ctxt.Bso.Flush()
	}

	f, err := elf.Open(libpath)
	if err != nil {
		Diag("cannot open shared library: %s", libpath)
		return
	}
	defer f.Close()
	syms, err := f.Symbols()
	if err != nil {
		Diag("cannot read symbols from shared library: %s", libpath)
		return
	}
	// If a package has a global variable of a type defined in another shared
	// library, we need to know the gcmask used by the type, if any.  To support
	// this, we read all the runtime.gcbits.* symbols, keep a map of address to
	// gcmask, and after we're read all the symbols, read the addresses of the
	// gcmasks symbols out of the type data to look up the gcmask for each type.
	// This depends on the fact that the runtime.gcbits.* symbols are local (so
	// the address is actually present in the type data and we don't have to
	// search all relocations to find the ones which correspond to gcmasks) and
	// also that the shared library we are linking against has not had the symbol
	// table removed.
	gcmasks := make(map[uint64][]byte)
	types := []*LSym{}
	var hash []byte
	for _, s := range syms {
		if elf.ST_TYPE(s.Info) == elf.STT_NOTYPE || elf.ST_TYPE(s.Info) == elf.STT_SECTION {
			continue
		}
		if s.Section == elf.SHN_UNDEF {
			continue
		}
		if strings.HasPrefix(s.Name, "_") {
			continue
		}
		if strings.HasPrefix(s.Name, "runtime.gcbits.") {
			gcmasks[s.Value] = readelfsymboldata(f, &s)
		}
		if s.Name == "go.link.abihashbytes" {
			hash = readelfsymboldata(f, &s)
		}
		if elf.ST_BIND(s.Info) != elf.STB_GLOBAL {
			continue
		}
		lsym := Linklookup(Ctxt, s.Name, 0)
		if lsym.Type != 0 && lsym.Dupok == 0 {
			Diag(
				"Found duplicate symbol %s reading from %s, first found in %s",
				s.Name, shlib, lsym.File)
		}
		lsym.Type = obj.SDYNIMPORT
		lsym.ElfType = elf.ST_TYPE(s.Info)
		lsym.File = libpath
		if strings.HasPrefix(lsym.Name, "type.") {
			if f.Sections[s.Section].Type == elf.SHT_PROGBITS {
				lsym.P = readelfsymboldata(f, &s)
			}
			if !strings.HasPrefix(lsym.Name, "type..") {
				types = append(types, lsym)
			}
		}
	}

	for _, t := range types {
		if decodetype_noptr(t) != 0 || decodetype_usegcprog(t) != 0 {
			continue
		}
		addr := decodetype_gcprog_shlib(t)
		tgcmask, ok := gcmasks[addr]
		if !ok {
			Diag("bits not found for %s at %d", t.Name, addr)
		}
		t.gcmask = tgcmask
	}

	// We might have overwritten some functions above (this tends to happen for the
	// autogenerated type equality/hashing functions) and we don't want to generated
	// pcln table entries for these any more so unstitch them from the Textp linked
	// list.
	var last *LSym

	for s := Ctxt.Textp; s != nil; s = s.Next {
		if s.Type == obj.SDYNIMPORT {
			continue
		}

		if last == nil {
			Ctxt.Textp = s
		} else {
			last.Next = s
		}
		last = s
	}

	if last == nil {
		Ctxt.Textp = nil
		Ctxt.Etextp = nil
	} else {
		last.Next = nil
		Ctxt.Etextp = last
	}

	Ctxt.Shlibs = append(Ctxt.Shlibs, Shlib{Path: libpath, Hash: hash})
}
Example #24
0
func deadcode() {
	if Debug['v'] != 0 {
		fmt.Fprintf(&Bso, "%5.2f deadcode\n", obj.Cputime())
	}

	mark(Linklookup(Ctxt, INITENTRY, 0))
	for i := 0; i < len(markextra); i++ {
		mark(Linklookup(Ctxt, markextra[i], 0))
	}

	for i := 0; i < len(dynexp); i++ {
		mark(dynexp[i])
	}

	markflood()

	// keep each beginning with 'typelink.' if the symbol it points at is being kept.
	for s := Ctxt.Allsym; s != nil; s = s.Allsym {
		if strings.HasPrefix(s.Name, "go.typelink.") {
			s.Reachable = len(s.R) == 1 && s.R[0].Sym.Reachable
		}
	}

	// remove dead text but keep file information (z symbols).
	var last *LSym

	for s := Ctxt.Textp; s != nil; s = s.Next {
		if !s.Reachable {
			continue
		}

		// NOTE: Removing s from old textp and adding to new, shorter textp.
		if last == nil {
			Ctxt.Textp = s
		} else {
			last.Next = s
		}
		last = s
	}

	if last == nil {
		Ctxt.Textp = nil
	} else {
		last.Next = nil
	}

	for s := Ctxt.Allsym; s != nil; s = s.Allsym {
		if strings.HasPrefix(s.Name, "go.weak.") {
			s.Special = 1 // do not lay out in data segment
			s.Reachable = true
			s.Hide = 1
		}
	}

	// record field tracking references
	var buf bytes.Buffer
	var p *LSym
	for s := Ctxt.Allsym; s != nil; s = s.Allsym {
		if strings.HasPrefix(s.Name, "go.track.") {
			s.Special = 1 // do not lay out in data segment
			s.Hide = 1
			if s.Reachable {
				buf.WriteString(s.Name[9:])
				for p = s.Reachparent; p != nil; p = p.Reachparent {
					buf.WriteString("\t")
					buf.WriteString(p.Name)
				}
				buf.WriteString("\n")
			}

			s.Type = SCONST
			s.Value = 0
		}
	}

	if tracksym == "" {
		return
	}
	s := Linklookup(Ctxt, tracksym, 0)
	if !s.Reachable {
		return
	}
	addstrdata(tracksym, buf.String())
}
Example #25
0
func loadlib() {
	switch Buildmode {
	case BuildmodeCShared:
		s := Linklookup(Ctxt, "runtime.islibrary", 0)
		s.Dupok = 1
		Adduint8(Ctxt, s, 1)
	case BuildmodeCArchive:
		s := Linklookup(Ctxt, "runtime.isarchive", 0)
		s.Dupok = 1
		Adduint8(Ctxt, s, 1)
	}

	loadinternal("runtime")
	if Thearch.Thechar == '5' {
		loadinternal("math")
	}
	if flag_race != 0 {
		loadinternal("runtime/race")
	}

	var i int
	for i = 0; i < len(Ctxt.Library); i++ {
		if Debug['v'] > 1 {
			fmt.Fprintf(&Bso, "%5.2f autolib: %s (from %s)\n", obj.Cputime(), Ctxt.Library[i].File, Ctxt.Library[i].Objref)
		}
		iscgo = iscgo || Ctxt.Library[i].Pkg == "runtime/cgo"
		if Ctxt.Library[i].Shlib != "" {
			ldshlibsyms(Ctxt.Library[i].Shlib)
		} else {
			objfile(Ctxt.Library[i])
		}
	}

	if Linkmode == LinkAuto {
		if iscgo && externalobj {
			Linkmode = LinkExternal
		} else {
			Linkmode = LinkInternal
		}

		// Force external linking for android.
		if goos == "android" {
			Linkmode = LinkExternal
		}

		// cgo on Darwin must use external linking
		// we can always use external linking, but then there will be circular
		// dependency problems when compiling natively (external linking requires
		// runtime/cgo, runtime/cgo requires cmd/cgo, but cmd/cgo needs to be
		// compiled using external linking.)
		if (Thearch.Thechar == '5' || Thearch.Thechar == '7') && HEADTYPE == obj.Hdarwin && iscgo {
			Linkmode = LinkExternal
		}
	}

	// cmd/7l doesn't support cgo internal linking
	// This is https://golang.org/issue/10373.
	if iscgo && goarch == "arm64" {
		Linkmode = LinkExternal
	}

	if Linkmode == LinkExternal && !iscgo {
		// This indicates a user requested -linkmode=external.
		// The startup code uses an import of runtime/cgo to decide
		// whether to initialize the TLS.  So give it one.  This could
		// be handled differently but it's an unusual case.
		loadinternal("runtime/cgo")

		if i < len(Ctxt.Library) {
			if Ctxt.Library[i].Shlib != "" {
				ldshlibsyms(Ctxt.Library[i].Shlib)
			} else {
				if DynlinkingGo() {
					Exitf("cannot implicitly include runtime/cgo in a shared library")
				}
				objfile(Ctxt.Library[i])
			}
		}
	}

	if Linkmode == LinkInternal {
		// Drop all the cgo_import_static declarations.
		// Turns out we won't be needing them.
		for s := Ctxt.Allsym; s != nil; s = s.Allsym {
			if s.Type == obj.SHOSTOBJ {
				// If a symbol was marked both
				// cgo_import_static and cgo_import_dynamic,
				// then we want to make it cgo_import_dynamic
				// now.
				if s.Extname != "" && s.Dynimplib != "" && s.Cgoexport == 0 {
					s.Type = obj.SDYNIMPORT
				} else {
					s.Type = 0
				}
			}
		}
	}

	tlsg := Linklookup(Ctxt, "runtime.tlsg", 0)

	// For most ports, runtime.tlsg is a placeholder symbol for TLS
	// relocation. However, the Android and Darwin arm ports need it
	// to be a real variable.
	//
	// TODO(crawshaw): android should require leaving the tlsg->type
	// alone (as the runtime-provided SNOPTRBSS) just like darwin/arm.
	// But some other part of the linker is expecting STLSBSS.
	if tlsg.Type != obj.SDYNIMPORT && (goos != "darwin" || Thearch.Thechar != '5') {
		tlsg.Type = obj.STLSBSS
	}
	tlsg.Size = int64(Thearch.Ptrsize)
	tlsg.Reachable = true
	Ctxt.Tlsg = tlsg

	// Now that we know the link mode, trim the dynexp list.
	x := CgoExportDynamic

	if Linkmode == LinkExternal {
		x = CgoExportStatic
	}
	w := 0
	for i := 0; i < len(dynexp); i++ {
		if int(dynexp[i].Cgoexport)&x != 0 {
			dynexp[w] = dynexp[i]
			w++
		}
	}
	dynexp = dynexp[:w]

	// In internal link mode, read the host object files.
	if Linkmode == LinkInternal {
		hostobjs()
	} else {
		hostlinksetup()
	}

	// We've loaded all the code now.
	// If there are no dynamic libraries needed, gcc disables dynamic linking.
	// Because of this, glibc's dynamic ELF loader occasionally (like in version 2.13)
	// assumes that a dynamic binary always refers to at least one dynamic library.
	// Rather than be a source of test cases for glibc, disable dynamic linking
	// the same way that gcc would.
	//
	// Exception: on OS X, programs such as Shark only work with dynamic
	// binaries, so leave it enabled on OS X (Mach-O) binaries.
	// Also leave it enabled on Solaris which doesn't support
	// statically linked binaries.
	if Buildmode == BuildmodeExe && havedynamic == 0 && HEADTYPE != obj.Hdarwin && HEADTYPE != obj.Hsolaris {
		Debug['d'] = 1
	}

	importcycles()
}
Example #26
0
File: ldpe.go Project: achanda/go
func ldpeError(ctxt *Link, input *bio.Reader, pkg string, length int64, pn string) error {
	if ctxt.Debugvlog != 0 {
		ctxt.Logf("%5.2f ldpe %s\n", obj.Cputime(), pn)
	}

	localSymVersion := ctxt.Syms.IncVersion()

	sectsyms := make(map[*pe.Section]*Symbol)
	sectdata := make(map[*pe.Section][]byte)

	// Some input files are archives containing multiple of
	// object files, and pe.NewFile seeks to the start of
	// input file and get confused. Create section reader
	// to stop pe.NewFile looking before current position.
	sr := io.NewSectionReader((*peBiobuf)(input), input.Offset(), 1<<63-1)

	// TODO: replace pe.NewFile with pe.Load (grep for "add Load function" in debug/pe for details)
	f, err := pe.NewFile(sr)
	if err != nil {
		return err
	}
	defer f.Close()

	// TODO return error if found .cormeta

	// create symbols for mapped sections
	for _, sect := range f.Sections {
		if sect.Characteristics&IMAGE_SCN_MEM_DISCARDABLE != 0 {
			continue
		}

		if sect.Characteristics&(IMAGE_SCN_CNT_CODE|IMAGE_SCN_CNT_INITIALIZED_DATA|IMAGE_SCN_CNT_UNINITIALIZED_DATA) == 0 {
			// This has been seen for .idata sections, which we
			// want to ignore. See issues 5106 and 5273.
			continue
		}

		data, err := sect.Data()
		if err != nil {
			return err
		}
		sectdata[sect] = data

		name := fmt.Sprintf("%s(%s)", pkg, sect.Name)
		s := ctxt.Syms.Lookup(name, localSymVersion)

		switch sect.Characteristics & (IMAGE_SCN_CNT_UNINITIALIZED_DATA | IMAGE_SCN_CNT_INITIALIZED_DATA | IMAGE_SCN_MEM_READ | IMAGE_SCN_MEM_WRITE | IMAGE_SCN_CNT_CODE | IMAGE_SCN_MEM_EXECUTE) {
		case IMAGE_SCN_CNT_INITIALIZED_DATA | IMAGE_SCN_MEM_READ: //.rdata
			s.Type = obj.SRODATA

		case IMAGE_SCN_CNT_UNINITIALIZED_DATA | IMAGE_SCN_MEM_READ | IMAGE_SCN_MEM_WRITE: //.bss
			s.Type = obj.SNOPTRBSS

		case IMAGE_SCN_CNT_INITIALIZED_DATA | IMAGE_SCN_MEM_READ | IMAGE_SCN_MEM_WRITE: //.data
			s.Type = obj.SNOPTRDATA

		case IMAGE_SCN_CNT_CODE | IMAGE_SCN_MEM_EXECUTE | IMAGE_SCN_MEM_READ: //.text
			s.Type = obj.STEXT

		default:
			return fmt.Errorf("unexpected flags %#06x for PE section %s", sect.Characteristics, sect.Name)
		}

		s.P = data
		s.Size = int64(len(data))
		sectsyms[sect] = s
		if sect.Name == ".rsrc" {
			setpersrc(ctxt, s)
		}
	}

	// load relocations
	for _, rsect := range f.Sections {
		if _, found := sectsyms[rsect]; !found {
			continue
		}
		if rsect.NumberOfRelocations == 0 {
			continue
		}
		if rsect.Characteristics&IMAGE_SCN_MEM_DISCARDABLE != 0 {
			continue
		}
		if rsect.Characteristics&(IMAGE_SCN_CNT_CODE|IMAGE_SCN_CNT_INITIALIZED_DATA|IMAGE_SCN_CNT_UNINITIALIZED_DATA) == 0 {
			// This has been seen for .idata sections, which we
			// want to ignore. See issues 5106 and 5273.
			continue
		}

		rs := make([]Reloc, rsect.NumberOfRelocations)
		for j, r := range rsect.Relocs {
			rp := &rs[j]
			if int(r.SymbolTableIndex) >= len(f.COFFSymbols) {
				return fmt.Errorf("relocation number %d symbol index idx=%d cannot be large then number of symbols %d", j, r.SymbolTableIndex, len(f.COFFSymbols))
			}
			pesym := &f.COFFSymbols[r.SymbolTableIndex]
			gosym, err := readpesym(ctxt, f, pesym, sectsyms, localSymVersion)
			if err != nil {
				return err
			}
			if gosym == nil {
				name, err := pesym.FullName(f.StringTable)
				if err != nil {
					name = string(pesym.Name[:])
				}
				return fmt.Errorf("reloc of invalid sym %s idx=%d type=%d", name, r.SymbolTableIndex, pesym.Type)
			}

			rp.Sym = gosym
			rp.Siz = 4
			rp.Off = int32(r.VirtualAddress)
			switch r.Type {
			default:
				Errorf(sectsyms[rsect], "%s: unknown relocation type %d;", pn, r.Type)
				fallthrough

			case IMAGE_REL_I386_REL32, IMAGE_REL_AMD64_REL32,
				IMAGE_REL_AMD64_ADDR32, // R_X86_64_PC32
				IMAGE_REL_AMD64_ADDR32NB:
				rp.Type = obj.R_PCREL

				rp.Add = int64(int32(Le32(sectdata[rsect][rp.Off:])))

			case IMAGE_REL_I386_DIR32NB, IMAGE_REL_I386_DIR32:
				rp.Type = obj.R_ADDR

				// load addend from image
				rp.Add = int64(int32(Le32(sectdata[rsect][rp.Off:])))

			case IMAGE_REL_AMD64_ADDR64: // R_X86_64_64
				rp.Siz = 8

				rp.Type = obj.R_ADDR

				// load addend from image
				rp.Add = int64(Le64(sectdata[rsect][rp.Off:]))
			}

			// ld -r could generate multiple section symbols for the
			// same section but with different values, we have to take
			// that into account
			if issect(pesym) {
				rp.Add += int64(pesym.Value)
			}
		}

		sort.Sort(rbyoff(rs[:rsect.NumberOfRelocations]))

		s := sectsyms[rsect]
		s.R = rs
		s.R = s.R[:rsect.NumberOfRelocations]
	}

	// enter sub-symbols into symbol table.
	for i, numaux := 0, 0; i < len(f.COFFSymbols); i += numaux + 1 {
		pesym := &f.COFFSymbols[i]

		numaux = int(pesym.NumberOfAuxSymbols)

		name, err := pesym.FullName(f.StringTable)
		if err != nil {
			return err
		}
		if name == "" {
			continue
		}
		if issect(pesym) {
			continue
		}
		if int(pesym.SectionNumber) > len(f.Sections) {
			continue
		}
		if pesym.SectionNumber == IMAGE_SYM_DEBUG {
			continue
		}
		var sect *pe.Section
		if pesym.SectionNumber > 0 {
			sect = f.Sections[pesym.SectionNumber-1]
			if _, found := sectsyms[sect]; !found {
				continue
			}
		}

		s, err := readpesym(ctxt, f, pesym, sectsyms, localSymVersion)
		if err != nil {
			return err
		}

		if pesym.SectionNumber == 0 { // extern
			if s.Type == obj.SDYNIMPORT {
				s.Plt = -2 // flag for dynimport in PE object files.
			}
			if s.Type == obj.SXREF && pesym.Value > 0 { // global data
				s.Type = obj.SNOPTRDATA
				s.Size = int64(pesym.Value)
			}

			continue
		} else if pesym.SectionNumber > 0 && int(pesym.SectionNumber) <= len(f.Sections) {
			sect = f.Sections[pesym.SectionNumber-1]
			if _, found := sectsyms[sect]; !found {
				Errorf(s, "%s: missing sect.sym", pn)
			}
		} else {
			Errorf(s, "%s: sectnum < 0!", pn)
		}

		if sect == nil {
			return nil
		}

		if s.Outer != nil {
			if s.Attr.DuplicateOK() {
				continue
			}
			Exitf("%s: duplicate symbol reference: %s in both %s and %s", pn, s.Name, s.Outer.Name, sectsyms[sect].Name)
		}

		sectsym := sectsyms[sect]
		s.Sub = sectsym.Sub
		sectsym.Sub = s
		s.Type = sectsym.Type | obj.SSUB
		s.Value = int64(pesym.Value)
		s.Size = 4
		s.Outer = sectsym
		if sectsym.Type == obj.STEXT {
			if s.Attr.External() && !s.Attr.DuplicateOK() {
				Errorf(s, "%s: duplicate symbol definition", pn)
			}
			s.Attr |= AttrExternal
		}
	}

	// Sort outer lists by address, adding to textp.
	// This keeps textp in increasing address order.
	for _, sect := range f.Sections {
		s := sectsyms[sect]
		if s == nil {
			continue
		}
		if s.Sub != nil {
			s.Sub = listsort(s.Sub)
		}
		if s.Type == obj.STEXT {
			if s.Attr.OnList() {
				log.Fatalf("symbol %s listed multiple times", s.Name)
			}
			s.Attr |= AttrOnList
			ctxt.Textp = append(ctxt.Textp, s)
			for s = s.Sub; s != nil; s = s.Sub {
				if s.Attr.OnList() {
					log.Fatalf("symbol %s listed multiple times", s.Name)
				}
				s.Attr |= AttrOnList
				ctxt.Textp = append(ctxt.Textp, s)
			}
		}
	}

	return nil
}
Example #27
0
func ldelf(f *Biobuf, pkg string, length int64, pn string) {
	if Debug['v'] != 0 {
		fmt.Fprintf(&Bso, "%5.2f ldelf %s\n", obj.Cputime(), pn)
	}

	Ctxt.Version++
	base := int32(Boffset(f))

	var add uint64
	var e binary.ByteOrder
	var elfobj *ElfObj
	var err error
	var flag int
	var hdr *ElfHdrBytes
	var hdrbuf [64]uint8
	var info uint64
	var is64 int
	var j int
	var n int
	var name string
	var p []byte
	var r []Reloc
	var rela int
	var rp *Reloc
	var rsect *ElfSect
	var s *LSym
	var sect *ElfSect
	var sym ElfSym
	var symbols []*LSym
	if Bread(f, hdrbuf[:]) != len(hdrbuf) {
		goto bad
	}
	hdr = new(ElfHdrBytes)
	binary.Read(bytes.NewReader(hdrbuf[:]), binary.BigEndian, hdr) // only byte arrays; byte order doesn't matter
	if string(hdr.Ident[:4]) != "\x7FELF" {
		goto bad
	}
	switch hdr.Ident[5] {
	case ElfDataLsb:
		e = binary.LittleEndian

	case ElfDataMsb:
		e = binary.BigEndian

	default:
		goto bad
	}

	// read header
	elfobj = new(ElfObj)

	elfobj.e = e
	elfobj.f = f
	elfobj.base = int64(base)
	elfobj.length = length
	elfobj.name = pn

	is64 = 0
	if hdr.Ident[4] == ElfClass64 {
		is64 = 1
		hdr := new(ElfHdrBytes64)
		binary.Read(bytes.NewReader(hdrbuf[:]), binary.BigEndian, hdr) // only byte arrays; byte order doesn't matter
		elfobj.type_ = uint32(e.Uint16(hdr.Type[:]))
		elfobj.machine = uint32(e.Uint16(hdr.Machine[:]))
		elfobj.version = e.Uint32(hdr.Version[:])
		elfobj.phoff = e.Uint64(hdr.Phoff[:])
		elfobj.shoff = e.Uint64(hdr.Shoff[:])
		elfobj.flags = e.Uint32(hdr.Flags[:])
		elfobj.ehsize = uint32(e.Uint16(hdr.Ehsize[:]))
		elfobj.phentsize = uint32(e.Uint16(hdr.Phentsize[:]))
		elfobj.phnum = uint32(e.Uint16(hdr.Phnum[:]))
		elfobj.shentsize = uint32(e.Uint16(hdr.Shentsize[:]))
		elfobj.shnum = uint32(e.Uint16(hdr.Shnum[:]))
		elfobj.shstrndx = uint32(e.Uint16(hdr.Shstrndx[:]))
	} else {
		elfobj.type_ = uint32(e.Uint16(hdr.Type[:]))
		elfobj.machine = uint32(e.Uint16(hdr.Machine[:]))
		elfobj.version = e.Uint32(hdr.Version[:])
		elfobj.entry = uint64(e.Uint32(hdr.Entry[:]))
		elfobj.phoff = uint64(e.Uint32(hdr.Phoff[:]))
		elfobj.shoff = uint64(e.Uint32(hdr.Shoff[:]))
		elfobj.flags = e.Uint32(hdr.Flags[:])
		elfobj.ehsize = uint32(e.Uint16(hdr.Ehsize[:]))
		elfobj.phentsize = uint32(e.Uint16(hdr.Phentsize[:]))
		elfobj.phnum = uint32(e.Uint16(hdr.Phnum[:]))
		elfobj.shentsize = uint32(e.Uint16(hdr.Shentsize[:]))
		elfobj.shnum = uint32(e.Uint16(hdr.Shnum[:]))
		elfobj.shstrndx = uint32(e.Uint16(hdr.Shstrndx[:]))
	}

	elfobj.is64 = is64

	if uint32(hdr.Ident[6]) != elfobj.version {
		goto bad
	}

	if e.Uint16(hdr.Type[:]) != ElfTypeRelocatable {
		Diag("%s: elf but not elf relocatable object", pn)
		return
	}

	switch Thearch.Thechar {
	default:
		Diag("%s: elf %s unimplemented", pn, Thestring)
		return

	case '5':
		if e != binary.LittleEndian || elfobj.machine != ElfMachArm || hdr.Ident[4] != ElfClass32 {
			Diag("%s: elf object but not arm", pn)
			return
		}

	case '6':
		if e != binary.LittleEndian || elfobj.machine != ElfMachAmd64 || hdr.Ident[4] != ElfClass64 {
			Diag("%s: elf object but not amd64", pn)
			return
		}

	case '7':
		if e != binary.LittleEndian || elfobj.machine != ElfMachArm64 || hdr.Ident[4] != ElfClass64 {
			Diag("%s: elf object but not arm64", pn)
			return
		}

	case '8':
		if e != binary.LittleEndian || elfobj.machine != ElfMach386 || hdr.Ident[4] != ElfClass32 {
			Diag("%s: elf object but not 386", pn)
			return
		}

	case '9':
		if elfobj.machine != ElfMachPower64 || hdr.Ident[4] != ElfClass64 {
			Diag("%s: elf object but not ppc64", pn)
			return
		}
	}

	// load section list into memory.
	elfobj.sect = make([]ElfSect, elfobj.shnum)

	elfobj.nsect = uint(elfobj.shnum)
	for i := 0; uint(i) < elfobj.nsect; i++ {
		if Bseek(f, int64(uint64(base)+elfobj.shoff+uint64(int64(i)*int64(elfobj.shentsize))), 0) < 0 {
			goto bad
		}
		sect = &elfobj.sect[i]
		if is64 != 0 {
			var b ElfSectBytes64

			if err = binary.Read(f, e, &b); err != nil {
				goto bad
			}

			sect.nameoff = uint32(e.Uint32(b.Name[:]))
			sect.type_ = e.Uint32(b.Type[:])
			sect.flags = e.Uint64(b.Flags[:])
			sect.addr = e.Uint64(b.Addr[:])
			sect.off = e.Uint64(b.Off[:])
			sect.size = e.Uint64(b.Size[:])
			sect.link = e.Uint32(b.Link[:])
			sect.info = e.Uint32(b.Info[:])
			sect.align = e.Uint64(b.Align[:])
			sect.entsize = e.Uint64(b.Entsize[:])
		} else {
			var b ElfSectBytes

			if err = binary.Read(f, e, &b); err != nil {
				goto bad
			}

			sect.nameoff = uint32(e.Uint32(b.Name[:]))
			sect.type_ = e.Uint32(b.Type[:])
			sect.flags = uint64(e.Uint32(b.Flags[:]))
			sect.addr = uint64(e.Uint32(b.Addr[:]))
			sect.off = uint64(e.Uint32(b.Off[:]))
			sect.size = uint64(e.Uint32(b.Size[:]))
			sect.link = e.Uint32(b.Link[:])
			sect.info = e.Uint32(b.Info[:])
			sect.align = uint64(e.Uint32(b.Align[:]))
			sect.entsize = uint64(e.Uint32(b.Entsize[:]))
		}
	}

	// read section string table and translate names
	if elfobj.shstrndx >= uint32(elfobj.nsect) {
		err = fmt.Errorf("shstrndx out of range %d >= %d", elfobj.shstrndx, elfobj.nsect)
		goto bad
	}

	sect = &elfobj.sect[elfobj.shstrndx]
	if err = elfmap(elfobj, sect); err != nil {
		goto bad
	}
	for i := 0; uint(i) < elfobj.nsect; i++ {
		if elfobj.sect[i].nameoff != 0 {
			elfobj.sect[i].name = cstring(sect.base[elfobj.sect[i].nameoff:])
		}
	}

	// load string table for symbols into memory.
	elfobj.symtab = section(elfobj, ".symtab")

	if elfobj.symtab == nil {
		// our work is done here - no symbols means nothing can refer to this file
		return
	}

	if elfobj.symtab.link <= 0 || elfobj.symtab.link >= uint32(elfobj.nsect) {
		Diag("%s: elf object has symbol table with invalid string table link", pn)
		return
	}

	elfobj.symstr = &elfobj.sect[elfobj.symtab.link]
	if is64 != 0 {
		elfobj.nsymtab = int(elfobj.symtab.size / ELF64SYMSIZE)
	} else {
		elfobj.nsymtab = int(elfobj.symtab.size / ELF32SYMSIZE)
	}

	if err = elfmap(elfobj, elfobj.symtab); err != nil {
		goto bad
	}
	if err = elfmap(elfobj, elfobj.symstr); err != nil {
		goto bad
	}

	// load text and data segments into memory.
	// they are not as small as the section lists, but we'll need
	// the memory anyway for the symbol images, so we might
	// as well use one large chunk.

	// create symbols for elfmapped sections
	for i := 0; uint(i) < elfobj.nsect; i++ {
		sect = &elfobj.sect[i]
		if (sect.type_ != ElfSectProgbits && sect.type_ != ElfSectNobits) || sect.flags&ElfSectFlagAlloc == 0 {
			continue
		}
		if sect.type_ != ElfSectNobits {
			if err = elfmap(elfobj, sect); err != nil {
				goto bad
			}
		}

		name = fmt.Sprintf("%s(%s)", pkg, sect.name)
		s = Linklookup(Ctxt, name, Ctxt.Version)

		switch int(sect.flags) & (ElfSectFlagAlloc | ElfSectFlagWrite | ElfSectFlagExec) {
		default:
			err = fmt.Errorf("unexpected flags for ELF section %s", sect.name)
			goto bad

		case ElfSectFlagAlloc:
			s.Type = SRODATA

		case ElfSectFlagAlloc + ElfSectFlagWrite:
			if sect.type_ == ElfSectNobits {
				s.Type = SNOPTRBSS
			} else {
				s.Type = SNOPTRDATA
			}

		case ElfSectFlagAlloc + ElfSectFlagExec:
			s.Type = STEXT
		}

		if sect.name == ".got" || sect.name == ".toc" {
			s.Type = SELFGOT
		}
		if sect.type_ == ElfSectProgbits {
			s.P = sect.base
			s.P = s.P[:sect.size]
		}

		s.Size = int64(sect.size)
		s.Align = int32(sect.align)
		sect.sym = s
	}

	// enter sub-symbols into symbol table.
	// symbol 0 is the null symbol.
	symbols = make([]*LSym, elfobj.nsymtab)

	if symbols == nil {
		Diag("out of memory")
		Errorexit()
	}

	for i := 1; i < elfobj.nsymtab; i++ {
		if err = readelfsym(elfobj, i, &sym, 1); err != nil {
			goto bad
		}
		symbols[i] = sym.sym
		if sym.type_ != ElfSymTypeFunc && sym.type_ != ElfSymTypeObject && sym.type_ != ElfSymTypeNone {
			continue
		}
		if sym.shndx == ElfSymShnCommon {
			s = sym.sym
			if uint64(s.Size) < sym.size {
				s.Size = int64(sym.size)
			}
			if s.Type == 0 || s.Type == SXREF {
				s.Type = SNOPTRBSS
			}
			continue
		}

		if uint(sym.shndx) >= elfobj.nsect || sym.shndx == 0 {
			continue
		}

		// even when we pass needSym == 1 to readelfsym, it might still return nil to skip some unwanted symbols
		if sym.sym == nil {
			continue
		}
		sect = &elfobj.sect[sym.shndx:][0]
		if sect.sym == nil {
			if strings.HasPrefix(sym.name, ".Linfo_string") { // clang does this
				continue
			}
			Diag("%s: sym#%d: ignoring %s in section %d (type %d)", pn, i, sym.name, sym.shndx, sym.type_)
			continue
		}

		s = sym.sym
		if s.Outer != nil {
			if s.Dupok != 0 {
				continue
			}
			Diag("%s: duplicate symbol reference: %s in both %s and %s", pn, s.Name, s.Outer.Name, sect.sym.Name)
			Errorexit()
		}

		s.Sub = sect.sym.Sub
		sect.sym.Sub = s
		s.Type = sect.sym.Type | s.Type&^SMASK | SSUB
		if s.Cgoexport&CgoExportDynamic == 0 {
			s.Dynimplib = "" // satisfy dynimport
		}
		s.Value = int64(sym.value)
		s.Size = int64(sym.size)
		s.Outer = sect.sym
		if sect.sym.Type == STEXT {
			if s.External != 0 && s.Dupok == 0 {
				Diag("%s: duplicate definition of %s", pn, s.Name)
			}
			s.External = 1
		}

		if elfobj.machine == ElfMachPower64 {
			flag = int(sym.other) >> 5
			if 2 <= flag && flag <= 6 {
				s.Localentry = 1 << uint(flag-2)
			} else if flag == 7 {
				Diag("%s: invalid sym.other 0x%x for %s", pn, sym.other, s.Name)
			}
		}
	}

	// Sort outer lists by address, adding to textp.
	// This keeps textp in increasing address order.
	for i := 0; uint(i) < elfobj.nsect; i++ {
		s = elfobj.sect[i].sym
		if s == nil {
			continue
		}
		if s.Sub != nil {
			s.Sub = listsort(s.Sub, valuecmp, listsubp)
		}
		if s.Type == STEXT {
			if s.Onlist != 0 {
				log.Fatalf("symbol %s listed multiple times", s.Name)
			}
			s.Onlist = 1
			if Ctxt.Etextp != nil {
				Ctxt.Etextp.Next = s
			} else {
				Ctxt.Textp = s
			}
			Ctxt.Etextp = s
			for s = s.Sub; s != nil; s = s.Sub {
				if s.Onlist != 0 {
					log.Fatalf("symbol %s listed multiple times", s.Name)
				}
				s.Onlist = 1
				Ctxt.Etextp.Next = s
				Ctxt.Etextp = s
			}
		}
	}

	// load relocations
	for i := 0; uint(i) < elfobj.nsect; i++ {
		rsect = &elfobj.sect[i]
		if rsect.type_ != ElfSectRela && rsect.type_ != ElfSectRel {
			continue
		}
		if rsect.info >= uint32(elfobj.nsect) || elfobj.sect[rsect.info].base == nil {
			continue
		}
		sect = &elfobj.sect[rsect.info]
		if err = elfmap(elfobj, rsect); err != nil {
			goto bad
		}
		rela = 0
		if rsect.type_ == ElfSectRela {
			rela = 1
		}
		n = int(rsect.size / uint64(4+4*is64) / uint64(2+rela))
		r = make([]Reloc, n)
		p = rsect.base
		for j = 0; j < n; j++ {
			add = 0
			rp = &r[j]
			if is64 != 0 {
				// 64-bit rel/rela
				rp.Off = int32(e.Uint64(p))

				p = p[8:]
				info = e.Uint64(p)
				p = p[8:]
				if rela != 0 {
					add = e.Uint64(p)
					p = p[8:]
				}
			} else {
				// 32-bit rel/rela
				rp.Off = int32(e.Uint32(p))

				p = p[4:]
				info = uint64(e.Uint32(p))
				info = info>>8<<32 | info&0xff // convert to 64-bit info
				p = p[4:]
				if rela != 0 {
					add = uint64(e.Uint32(p))
					p = p[4:]
				}
			}

			if info&0xffffffff == 0 { // skip R_*_NONE relocation
				j--
				n--
				continue
			}

			if info>>32 == 0 { // absolute relocation, don't bother reading the null symbol
				rp.Sym = nil
			} else {
				if err = readelfsym(elfobj, int(info>>32), &sym, 0); err != nil {
					goto bad
				}
				sym.sym = symbols[info>>32]
				if sym.sym == nil {
					err = fmt.Errorf("%s#%d: reloc of invalid sym #%d %s shndx=%d type=%d", sect.sym.Name, j, int(info>>32), sym.name, sym.shndx, sym.type_)
					goto bad
				}

				rp.Sym = sym.sym
			}

			rp.Type = int32(reltype(pn, int(uint32(info)), &rp.Siz))
			if rela != 0 {
				rp.Add = int64(add)
			} else {
				// load addend from image
				if rp.Siz == 4 {
					rp.Add = int64(e.Uint32(sect.base[rp.Off:]))
				} else if rp.Siz == 8 {
					rp.Add = int64(e.Uint64(sect.base[rp.Off:]))
				} else {
					Diag("invalid rela size %d", rp.Siz)
				}
			}

			if rp.Siz == 2 {
				rp.Add = int64(int16(rp.Add))
			}
			if rp.Siz == 4 {
				rp.Add = int64(int32(rp.Add))
			}
		}

		//print("rel %s %d %d %s %#llx\n", sect->sym->name, rp->type, rp->siz, rp->sym->name, rp->add);
		sort.Sort(rbyoff(r[:n]))
		// just in case

		s = sect.sym
		s.R = r
		s.R = s.R[:n]
	}

	return

bad:
	Diag("%s: malformed elf file: %v", pn, err)
}
Example #28
0
File: ldpe.go Project: 4ad/go
func ldpe(f *obj.Biobuf, pkg string, length int64, pn string) {
	if Debug['v'] != 0 {
		fmt.Fprintf(&Bso, "%5.2f ldpe %s\n", obj.Cputime(), pn)
	}

	var sect *PeSect
	Ctxt.Version++
	base := int32(obj.Boffset(f))

	peobj := new(PeObj)
	peobj.f = f
	peobj.base = uint32(base)
	peobj.name = pn

	// read header
	var err error
	var j int
	var l uint32
	var name string
	var numaux int
	var r []Reloc
	var rp *Reloc
	var rsect *PeSect
	var s *LSym
	var sym *PeSym
	var symbuf [18]uint8
	if err = binary.Read(f, binary.LittleEndian, &peobj.fh); err != nil {
		goto bad
	}

	// load section list
	peobj.sect = make([]PeSect, peobj.fh.NumberOfSections)

	peobj.nsect = uint(peobj.fh.NumberOfSections)
	for i := 0; i < int(peobj.fh.NumberOfSections); i++ {
		if err = binary.Read(f, binary.LittleEndian, &peobj.sect[i].sh); err != nil {
			goto bad
		}
		peobj.sect[i].size = uint64(peobj.sect[i].sh.SizeOfRawData)
		peobj.sect[i].name = cstring(peobj.sect[i].sh.Name[:])
	}

	// TODO return error if found .cormeta

	// load string table
	obj.Bseek(f, int64(base)+int64(peobj.fh.PointerToSymbolTable)+int64(len(symbuf))*int64(peobj.fh.NumberOfSymbols), 0)

	if obj.Bread(f, symbuf[:4]) != 4 {
		goto bad
	}
	l = Le32(symbuf[:])
	peobj.snames = make([]byte, l)
	obj.Bseek(f, int64(base)+int64(peobj.fh.PointerToSymbolTable)+int64(len(symbuf))*int64(peobj.fh.NumberOfSymbols), 0)
	if obj.Bread(f, peobj.snames) != len(peobj.snames) {
		goto bad
	}

	// rewrite section names if they start with /
	for i := 0; i < int(peobj.fh.NumberOfSections); i++ {
		if peobj.sect[i].name == "" {
			continue
		}
		if peobj.sect[i].name[0] != '/' {
			continue
		}
		n, _ := strconv.Atoi(peobj.sect[i].name[1:])
		peobj.sect[i].name = cstring(peobj.snames[n:])
	}

	// read symbols
	peobj.pesym = make([]PeSym, peobj.fh.NumberOfSymbols)

	peobj.npesym = uint(peobj.fh.NumberOfSymbols)
	obj.Bseek(f, int64(base)+int64(peobj.fh.PointerToSymbolTable), 0)
	for i := 0; uint32(i) < peobj.fh.NumberOfSymbols; i += numaux + 1 {
		obj.Bseek(f, int64(base)+int64(peobj.fh.PointerToSymbolTable)+int64(len(symbuf))*int64(i), 0)
		if obj.Bread(f, symbuf[:]) != len(symbuf) {
			goto bad
		}

		if (symbuf[0] == 0) && (symbuf[1] == 0) && (symbuf[2] == 0) && (symbuf[3] == 0) {
			l = Le32(symbuf[4:])
			peobj.pesym[i].name = cstring(peobj.snames[l:]) // sym name length <= 8
		} else {
			peobj.pesym[i].name = cstring(symbuf[:8])
		}

		peobj.pesym[i].value = Le32(symbuf[8:])
		peobj.pesym[i].sectnum = Le16(symbuf[12:])
		peobj.pesym[i].sclass = symbuf[16]
		peobj.pesym[i].aux = symbuf[17]
		peobj.pesym[i].type_ = Le16(symbuf[14:])
		numaux = int(peobj.pesym[i].aux)
		if numaux < 0 {
			numaux = 0
		}
	}

	// create symbols for mapped sections
	for i := 0; uint(i) < peobj.nsect; i++ {
		sect = &peobj.sect[i]
		if sect.sh.Characteristics&IMAGE_SCN_MEM_DISCARDABLE != 0 {
			continue
		}

		if sect.sh.Characteristics&(IMAGE_SCN_CNT_CODE|IMAGE_SCN_CNT_INITIALIZED_DATA|IMAGE_SCN_CNT_UNINITIALIZED_DATA) == 0 {
			// This has been seen for .idata sections, which we
			// want to ignore. See issues 5106 and 5273.
			continue
		}

		if pemap(peobj, sect) < 0 {
			goto bad
		}

		name = fmt.Sprintf("%s(%s)", pkg, sect.name)
		s = Linklookup(Ctxt, name, Ctxt.Version)

		switch sect.sh.Characteristics & (IMAGE_SCN_CNT_UNINITIALIZED_DATA | IMAGE_SCN_CNT_INITIALIZED_DATA | IMAGE_SCN_MEM_READ | IMAGE_SCN_MEM_WRITE | IMAGE_SCN_CNT_CODE | IMAGE_SCN_MEM_EXECUTE) {
		case IMAGE_SCN_CNT_INITIALIZED_DATA | IMAGE_SCN_MEM_READ: //.rdata
			s.Type = obj.SRODATA

		case IMAGE_SCN_CNT_UNINITIALIZED_DATA | IMAGE_SCN_MEM_READ | IMAGE_SCN_MEM_WRITE: //.bss
			s.Type = obj.SNOPTRBSS

		case IMAGE_SCN_CNT_INITIALIZED_DATA | IMAGE_SCN_MEM_READ | IMAGE_SCN_MEM_WRITE: //.data
			s.Type = obj.SNOPTRDATA

		case IMAGE_SCN_CNT_CODE | IMAGE_SCN_MEM_EXECUTE | IMAGE_SCN_MEM_READ: //.text
			s.Type = obj.STEXT

		default:
			err = fmt.Errorf("unexpected flags %#06x for PE section %s", sect.sh.Characteristics, sect.name)
			goto bad
		}

		s.P = sect.base
		s.P = s.P[:sect.size]
		s.Size = int64(sect.size)
		sect.sym = s
		if sect.name == ".rsrc" {
			setpersrc(sect.sym)
		}
	}

	// load relocations
	for i := 0; uint(i) < peobj.nsect; i++ {
		rsect = &peobj.sect[i]
		if rsect.sym == nil || rsect.sh.NumberOfRelocations == 0 {
			continue
		}
		if rsect.sh.Characteristics&IMAGE_SCN_MEM_DISCARDABLE != 0 {
			continue
		}
		if sect.sh.Characteristics&(IMAGE_SCN_CNT_CODE|IMAGE_SCN_CNT_INITIALIZED_DATA|IMAGE_SCN_CNT_UNINITIALIZED_DATA) == 0 {
			// This has been seen for .idata sections, which we
			// want to ignore. See issues 5106 and 5273.
			continue
		}

		r = make([]Reloc, rsect.sh.NumberOfRelocations)
		obj.Bseek(f, int64(peobj.base)+int64(rsect.sh.PointerToRelocations), 0)
		for j = 0; j < int(rsect.sh.NumberOfRelocations); j++ {
			rp = &r[j]
			if obj.Bread(f, symbuf[:10]) != 10 {
				goto bad
			}
			rva := Le32(symbuf[0:])
			symindex := Le32(symbuf[4:])
			type_ := Le16(symbuf[8:])
			if err = readpesym(peobj, int(symindex), &sym); err != nil {
				goto bad
			}
			if sym.sym == nil {
				err = fmt.Errorf("reloc of invalid sym %s idx=%d type=%d", sym.name, symindex, sym.type_)
				goto bad
			}

			rp.Sym = sym.sym
			rp.Siz = 4
			rp.Off = int32(rva)
			switch type_ {
			default:
				Diag("%s: unknown relocation type %d;", pn, type_)
				fallthrough

			case IMAGE_REL_I386_REL32, IMAGE_REL_AMD64_REL32,
				IMAGE_REL_AMD64_ADDR32, // R_X86_64_PC32
				IMAGE_REL_AMD64_ADDR32NB:
				rp.Type = obj.R_PCREL

				rp.Add = int64(int32(Le32(rsect.base[rp.Off:])))

			case IMAGE_REL_I386_DIR32NB, IMAGE_REL_I386_DIR32:
				rp.Type = obj.R_ADDR

				// load addend from image
				rp.Add = int64(int32(Le32(rsect.base[rp.Off:])))

			case IMAGE_REL_AMD64_ADDR64: // R_X86_64_64
				rp.Siz = 8

				rp.Type = obj.R_ADDR

				// load addend from image
				rp.Add = int64(Le64(rsect.base[rp.Off:]))
			}

			// ld -r could generate multiple section symbols for the
			// same section but with different values, we have to take
			// that into account
			if issect(&peobj.pesym[symindex]) {
				rp.Add += int64(peobj.pesym[symindex].value)
			}
		}

		sort.Sort(rbyoff(r[:rsect.sh.NumberOfRelocations]))

		s = rsect.sym
		s.R = r
		s.R = s.R[:rsect.sh.NumberOfRelocations]
	}

	// enter sub-symbols into symbol table.
	for i := 0; uint(i) < peobj.npesym; i++ {
		if peobj.pesym[i].name == "" {
			continue
		}
		if issect(&peobj.pesym[i]) {
			continue
		}
		if uint(peobj.pesym[i].sectnum) > peobj.nsect {
			continue
		}
		if peobj.pesym[i].sectnum > 0 {
			sect = &peobj.sect[peobj.pesym[i].sectnum-1]
			if sect.sym == nil {
				continue
			}
		}

		if err = readpesym(peobj, i, &sym); err != nil {
			goto bad
		}

		s = sym.sym
		if sym.sectnum == 0 { // extern
			if s.Type == obj.SDYNIMPORT {
				s.Plt = -2 // flag for dynimport in PE object files.
			}
			if s.Type == obj.SXREF && sym.value > 0 { // global data
				s.Type = obj.SNOPTRDATA
				s.Size = int64(sym.value)
			}

			continue
		} else if sym.sectnum > 0 && uint(sym.sectnum) <= peobj.nsect {
			sect = &peobj.sect[sym.sectnum-1]
			if sect.sym == nil {
				Diag("%s: %s sym == 0!", pn, s.Name)
			}
		} else {
			Diag("%s: %s sectnum < 0!", pn, s.Name)
		}

		if sect == nil {
			return
		}

		if s.Outer != nil {
			if s.Attr.DuplicateOK() {
				continue
			}
			Exitf("%s: duplicate symbol reference: %s in both %s and %s", pn, s.Name, s.Outer.Name, sect.sym.Name)
		}

		s.Sub = sect.sym.Sub
		sect.sym.Sub = s
		s.Type = sect.sym.Type | obj.SSUB
		s.Value = int64(sym.value)
		s.Size = 4
		s.Outer = sect.sym
		if sect.sym.Type == obj.STEXT {
			if s.Attr.External() && !s.Attr.DuplicateOK() {
				Diag("%s: duplicate definition of %s", pn, s.Name)
			}
			s.Attr |= AttrExternal
		}
	}

	// Sort outer lists by address, adding to textp.
	// This keeps textp in increasing address order.
	for i := 0; uint(i) < peobj.nsect; i++ {
		s = peobj.sect[i].sym
		if s == nil {
			continue
		}
		if s.Sub != nil {
			s.Sub = listsort(s.Sub, valuecmp, listsubp)
		}
		if s.Type == obj.STEXT {
			if s.Attr.OnList() {
				log.Fatalf("symbol %s listed multiple times", s.Name)
			}
			s.Attr |= AttrOnList
			if Ctxt.Etextp != nil {
				Ctxt.Etextp.Next = s
			} else {
				Ctxt.Textp = s
			}
			Ctxt.Etextp = s
			for s = s.Sub; s != nil; s = s.Sub {
				if s.Attr.OnList() {
					log.Fatalf("symbol %s listed multiple times", s.Name)
				}
				s.Attr |= AttrOnList
				Ctxt.Etextp.Next = s
				Ctxt.Etextp = s
			}
		}
	}

	return

bad:
	Diag("%s: malformed pe file: %v", pn, err)
}
Example #29
0
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))

	machlink := uint32(0)
	if ld.HEADTYPE == obj.Hdarwin {
		if ld.Debug['v'] != 0 {
			fmt.Fprintf(&ld.Bso, "%5.2f dwarf\n", obj.Cputime())
		}

		dwarfoff := uint32(ld.Rnd(int64(uint64(ld.HEADR)+ld.Segtext.Length), int64(ld.INITRND)) + ld.Rnd(int64(ld.Segdata.Filelen), int64(ld.INITRND)))
		ld.Cseek(int64(dwarfoff))

		ld.Segdwarf.Fileoff = uint64(ld.Cpos())
		ld.Dwarfemitdebugsections()
		ld.Segdwarf.Filelen = uint64(ld.Cpos()) - ld.Segdwarf.Fileoff

		machlink = uint32(ld.Domacholink())
	}

	ld.Symsize = 0
	ld.Spsize = 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)

		case obj.Hdarwin:
			symo = uint32(ld.Segdwarf.Fileoff + uint64(ld.Rnd(int64(ld.Segdwarf.Filelen), int64(ld.INITRND))) + uint64(machlink))

		case obj.Hwindows:
			symo = uint32(ld.Segdata.Fileoff + ld.Segdata.Filelen)
			symo = uint32(ld.Rnd(int64(symo), ld.PEFILEALIGN))
		}

		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()
			}

		case obj.Hwindows:
			if ld.Debug['v'] != 0 {
				fmt.Fprintf(&ld.Bso, "%5.2f dwarf\n", obj.Cputime())
			}
			ld.Dwarfemitdebugsections()

		case obj.Hdarwin:
			if ld.Linkmode == ld.LinkExternal {
				ld.Machoemitreloc()
			}
		}
	}

	if ld.Debug['v'] != 0 {
		fmt.Fprintf(&ld.Bso, "%5.2f headr\n", obj.Cputime())
	}
	ld.Bso.Flush()
	ld.Cseek(0)
	switch ld.HEADTYPE {
	default:
	case obj.Hplan9: /* plan9 */
		magic := int32(4*11*11 + 7)

		ld.Lputb(uint32(magic))              /* magic */
		ld.Lputb(uint32(ld.Segtext.Filelen)) /* sizes */
		ld.Lputb(uint32(ld.Segdata.Filelen))
		ld.Lputb(uint32(ld.Segdata.Length - ld.Segdata.Filelen))
		ld.Lputb(uint32(ld.Symsize))      /* nsyms */
		ld.Lputb(uint32(ld.Entryvalue())) /* va of entry */
		ld.Lputb(uint32(ld.Spsize))       /* sp offsets */
		ld.Lputb(uint32(ld.Lcsize))       /* line offsets */

	case obj.Hdarwin:
		ld.Asmbmacho()

	case obj.Hlinux,
		obj.Hfreebsd,
		obj.Hnetbsd,
		obj.Hopenbsd,
		obj.Hnacl:
		ld.Asmbelf(int64(symo))

	case obj.Hwindows:
		ld.Asmbpe()
	}

	ld.Cflush()
}
Example #30
0
File: data.go Project: danny8002/go
func dodata() {
	if Debug['v'] != 0 {
		fmt.Fprintf(&Bso, "%5.2f dodata\n", obj.Cputime())
	}
	Bso.Flush()

	var last *LSym
	datap = nil

	for s := Ctxt.Allsym; s != nil; s = s.Allsym {
		if !s.Reachable || s.Special != 0 {
			continue
		}
		if obj.STEXT < s.Type && s.Type < obj.SXREF {
			if s.Onlist != 0 {
				log.Fatalf("symbol %s listed multiple times", s.Name)
			}
			s.Onlist = 1
			if last == nil {
				datap = s
			} else {
				last.Next = s
			}
			s.Next = nil
			last = s
		}
	}

	for s := datap; s != nil; s = s.Next {
		if int64(len(s.P)) > s.Size {
			Diag("%s: initialize bounds (%d < %d)", s.Name, int64(s.Size), len(s.P))
		}
	}

	/*
	 * now that we have the datap list, but before we start
	 * to assign addresses, record all the necessary
	 * dynamic relocations.  these will grow the relocation
	 * symbol, which is itself data.
	 *
	 * on darwin, we need the symbol table numbers for dynreloc.
	 */
	if HEADTYPE == obj.Hdarwin {
		machosymorder()
	}
	dynreloc()

	/* some symbols may no longer belong in datap (Mach-O) */
	var l **LSym
	var s *LSym
	for l = &datap; ; {
		s = *l
		if s == nil {
			break
		}

		if s.Type <= obj.STEXT || obj.SXREF <= s.Type {
			*l = s.Next
		} else {
			l = &s.Next
		}
	}

	*l = nil

	if UseRelro() {
		// "read only" data with relocations needs to go in its own section
		// when building a shared library. We do this by boosting objects of
		// type SXXX with relocations to type SXXXRELRO.
		for s := datap; s != nil; s = s.Next {
			if (s.Type >= obj.STYPE && s.Type <= obj.SFUNCTAB && len(s.R) > 0) || s.Type == obj.SGOSTRING {
				s.Type += (obj.STYPERELRO - obj.STYPE)
				if s.Outer != nil {
					s.Outer.Type = s.Type
				}
			}
		}
		// Check that we haven't made two symbols with the same .Outer into
		// different types (because references two symbols with non-nil Outer
		// become references to the outer symbol + offset it's vital that the
		// symbol and the outer end up in the same section).
		for s := datap; s != nil; s = s.Next {
			if s.Outer != nil && s.Outer.Type != s.Type {
				Diag("inconsistent types for %s and its Outer %s (%d != %d)",
					s.Name, s.Outer.Name, s.Type, s.Outer.Type)
			}
		}

	}

	datap = listsort(datap, datcmp, listnextp)

	if Iself {
		// Make .rela and .rela.plt contiguous, the ELF ABI requires this
		// and Solaris actually cares.
		var relplt *LSym
		for l = &datap; *l != nil; l = &(*l).Next {
			if (*l).Name == ".rel.plt" || (*l).Name == ".rela.plt" {
				relplt = (*l)
				*l = (*l).Next
				break
			}
		}
		if relplt != nil {
			for s = datap; s != nil; s = s.Next {
				if s.Name == ".rel" || s.Name == ".rela" {
					relplt.Next = s.Next
					s.Next = relplt
				}
			}
		}
	}

	/*
	 * allocate sections.  list is sorted by type,
	 * so we can just walk it for each piece we want to emit.
	 * segdata is processed before segtext, because we need
	 * to see all symbols in the .data and .bss sections in order
	 * to generate garbage collection information.
	 */

	/* begin segdata */

	/* skip symbols belonging to segtext */
	s = datap

	for ; s != nil && s.Type < obj.SELFSECT; s = s.Next {
	}

	/* writable ELF sections */
	datsize := int64(0)

	var sect *Section
	for ; s != nil && s.Type < obj.SELFGOT; s = s.Next {
		sect = addsection(&Segdata, s.Name, 06)
		sect.Align = symalign(s)
		datsize = Rnd(datsize, int64(sect.Align))
		sect.Vaddr = uint64(datsize)
		s.Sect = sect
		s.Type = obj.SDATA
		s.Value = int64(uint64(datsize) - sect.Vaddr)
		growdatsize(&datsize, s)
		sect.Length = uint64(datsize) - sect.Vaddr
	}

	/* .got (and .toc on ppc64) */
	if s.Type == obj.SELFGOT {
		sect := addsection(&Segdata, ".got", 06)
		sect.Align = maxalign(s, obj.SELFGOT)
		datsize = Rnd(datsize, int64(sect.Align))
		sect.Vaddr = uint64(datsize)
		var toc *LSym
		for ; s != nil && s.Type == obj.SELFGOT; s = s.Next {
			datsize = aligndatsize(datsize, s)
			s.Sect = sect
			s.Type = obj.SDATA
			s.Value = int64(uint64(datsize) - sect.Vaddr)

			// Resolve .TOC. symbol for this object file (ppc64)
			toc = Linkrlookup(Ctxt, ".TOC.", int(s.Version))

			if toc != nil {
				toc.Sect = sect
				toc.Outer = s
				toc.Sub = s.Sub
				s.Sub = toc

				toc.Value = 0x8000
			}

			growdatsize(&datsize, s)
		}

		sect.Length = uint64(datsize) - sect.Vaddr
	}

	/* pointer-free data */
	sect = addsection(&Segdata, ".noptrdata", 06)

	sect.Align = maxalign(s, obj.SINITARR-1)
	datsize = Rnd(datsize, int64(sect.Align))
	sect.Vaddr = uint64(datsize)
	Linklookup(Ctxt, "runtime.noptrdata", 0).Sect = sect
	Linklookup(Ctxt, "runtime.enoptrdata", 0).Sect = sect
	for ; s != nil && s.Type < obj.SINITARR; s = s.Next {
		datsize = aligndatsize(datsize, s)
		s.Sect = sect
		s.Type = obj.SDATA
		s.Value = int64(uint64(datsize) - sect.Vaddr)
		growdatsize(&datsize, s)
	}

	sect.Length = uint64(datsize) - sect.Vaddr

	hasinitarr := Linkshared

	/* shared library initializer */
	switch Buildmode {
	case BuildmodeCArchive, BuildmodeCShared, BuildmodeShared:
		hasinitarr = true
	}

	if hasinitarr {
		sect := addsection(&Segdata, ".init_array", 06)
		sect.Align = maxalign(s, obj.SINITARR)
		datsize = Rnd(datsize, int64(sect.Align))
		sect.Vaddr = uint64(datsize)
		for ; s != nil && s.Type == obj.SINITARR; s = s.Next {
			datsize = aligndatsize(datsize, s)
			s.Sect = sect
			s.Value = int64(uint64(datsize) - sect.Vaddr)
			growdatsize(&datsize, s)
		}

		sect.Length = uint64(datsize) - sect.Vaddr
	}

	/* data */
	sect = addsection(&Segdata, ".data", 06)
	sect.Align = maxalign(s, obj.SBSS-1)
	datsize = Rnd(datsize, int64(sect.Align))
	sect.Vaddr = uint64(datsize)
	Linklookup(Ctxt, "runtime.data", 0).Sect = sect
	Linklookup(Ctxt, "runtime.edata", 0).Sect = sect
	var gc GCProg
	gc.Init("runtime.gcdata")
	for ; s != nil && s.Type < obj.SBSS; s = s.Next {
		if s.Type == obj.SINITARR {
			Ctxt.Cursym = s
			Diag("unexpected symbol type %d", s.Type)
		}

		s.Sect = sect
		s.Type = obj.SDATA
		datsize = aligndatsize(datsize, s)
		s.Value = int64(uint64(datsize) - sect.Vaddr)
		gc.AddSym(s)
		growdatsize(&datsize, s)
	}
	sect.Length = uint64(datsize) - sect.Vaddr
	gc.End(int64(sect.Length))

	/* bss */
	sect = addsection(&Segdata, ".bss", 06)
	sect.Align = maxalign(s, obj.SNOPTRBSS-1)
	datsize = Rnd(datsize, int64(sect.Align))
	sect.Vaddr = uint64(datsize)
	Linklookup(Ctxt, "runtime.bss", 0).Sect = sect
	Linklookup(Ctxt, "runtime.ebss", 0).Sect = sect
	gc = GCProg{}
	gc.Init("runtime.gcbss")
	for ; s != nil && s.Type < obj.SNOPTRBSS; s = s.Next {
		s.Sect = sect
		datsize = aligndatsize(datsize, s)
		s.Value = int64(uint64(datsize) - sect.Vaddr)
		gc.AddSym(s)
		growdatsize(&datsize, s)
	}
	sect.Length = uint64(datsize) - sect.Vaddr
	gc.End(int64(sect.Length))

	/* pointer-free bss */
	sect = addsection(&Segdata, ".noptrbss", 06)

	sect.Align = maxalign(s, obj.SNOPTRBSS)
	datsize = Rnd(datsize, int64(sect.Align))
	sect.Vaddr = uint64(datsize)
	Linklookup(Ctxt, "runtime.noptrbss", 0).Sect = sect
	Linklookup(Ctxt, "runtime.enoptrbss", 0).Sect = sect
	for ; s != nil && s.Type == obj.SNOPTRBSS; s = s.Next {
		datsize = aligndatsize(datsize, s)
		s.Sect = sect
		s.Value = int64(uint64(datsize) - sect.Vaddr)
		growdatsize(&datsize, s)
	}

	sect.Length = uint64(datsize) - sect.Vaddr
	Linklookup(Ctxt, "runtime.end", 0).Sect = sect

	// 6g uses 4-byte relocation offsets, so the entire segment must fit in 32 bits.
	if datsize != int64(uint32(datsize)) {
		Diag("data or bss segment too large")
	}

	if s != nil && s.Type == obj.STLSBSS {
		if Iself && (Linkmode == LinkExternal || Debug['d'] == 0) && HEADTYPE != obj.Hopenbsd {
			sect = addsection(&Segdata, ".tbss", 06)
			sect.Align = int32(Thearch.Ptrsize)
			sect.Vaddr = 0
		} else {
			sect = nil
		}
		datsize = 0

		for ; s != nil && s.Type == obj.STLSBSS; s = s.Next {
			datsize = aligndatsize(datsize, s)
			s.Sect = sect
			s.Value = datsize
			growdatsize(&datsize, s)
		}

		if sect != nil {
			sect.Length = uint64(datsize)
		}
	}

	if s != nil {
		Ctxt.Cursym = nil
		Diag("unexpected symbol type %d for %s", s.Type, s.Name)
	}

	/*
	 * We finished data, begin read-only data.
	 * Not all systems support a separate read-only non-executable data section.
	 * ELF systems do.
	 * OS X and Plan 9 do not.
	 * Windows PE may, but if so we have not implemented it.
	 * And if we're using external linking mode, the point is moot,
	 * since it's not our decision; that code expects the sections in
	 * segtext.
	 */
	var segro *Segment
	if Iself && Linkmode == LinkInternal {
		segro = &Segrodata
	} else {
		segro = &Segtext
	}

	s = datap

	datsize = 0

	/* read-only executable ELF, Mach-O sections */
	for ; s != nil && s.Type < obj.STYPE; s = s.Next {
		sect = addsection(&Segtext, s.Name, 04)
		sect.Align = symalign(s)
		datsize = Rnd(datsize, int64(sect.Align))
		sect.Vaddr = uint64(datsize)
		s.Sect = sect
		s.Type = obj.SRODATA
		s.Value = int64(uint64(datsize) - sect.Vaddr)
		growdatsize(&datsize, s)
		sect.Length = uint64(datsize) - sect.Vaddr
	}

	/* read-only data */
	sect = addsection(segro, ".rodata", 04)

	sect.Align = maxalign(s, obj.STYPERELRO-1)
	datsize = Rnd(datsize, int64(sect.Align))
	sect.Vaddr = 0
	Linklookup(Ctxt, "runtime.rodata", 0).Sect = sect
	Linklookup(Ctxt, "runtime.erodata", 0).Sect = sect
	for ; s != nil && s.Type < obj.STYPERELRO; s = s.Next {
		datsize = aligndatsize(datsize, s)
		s.Sect = sect
		s.Type = obj.SRODATA
		s.Value = int64(uint64(datsize) - sect.Vaddr)
		growdatsize(&datsize, s)
	}

	sect.Length = uint64(datsize) - sect.Vaddr

	// There is some data that are conceptually read-only but are written to by
	// relocations. On GNU systems, we can arrange for the dynamic linker to
	// mprotect sections after relocations are applied by giving them write
	// permissions in the object file and calling them ".data.rel.ro.FOO". We
	// divide the .rodata section between actual .rodata and .data.rel.ro.rodata,
	// but for the other sections that this applies to, we just write a read-only
	// .FOO section or a read-write .data.rel.ro.FOO section depending on the
	// situation.
	// TODO(mwhudson): It would make sense to do this more widely, but it makes
	// the system linker segfault on darwin.
	relro_perms := 04
	relro_prefix := ""

	if UseRelro() {
		relro_perms = 06
		relro_prefix = ".data.rel.ro"
		/* data only written by relocations */
		sect = addsection(segro, ".data.rel.ro", 06)

		sect.Align = maxalign(s, obj.STYPELINK-1)
		datsize = Rnd(datsize, int64(sect.Align))
		sect.Vaddr = 0
		for ; s != nil && s.Type < obj.STYPELINK; s = s.Next {
			datsize = aligndatsize(datsize, s)
			if s.Outer != nil && s.Outer.Sect != nil && s.Outer.Sect != sect {
				Diag("s.Outer (%s) in different section from s (%s)", s.Outer.Name, s.Name)
			}
			s.Sect = sect
			s.Type = obj.SRODATA
			s.Value = int64(uint64(datsize) - sect.Vaddr)
			growdatsize(&datsize, s)
		}

		sect.Length = uint64(datsize) - sect.Vaddr

	}

	/* typelink */
	sect = addsection(segro, relro_prefix+".typelink", relro_perms)

	sect.Align = maxalign(s, obj.STYPELINK)
	datsize = Rnd(datsize, int64(sect.Align))
	sect.Vaddr = uint64(datsize)
	Linklookup(Ctxt, "runtime.typelink", 0).Sect = sect
	Linklookup(Ctxt, "runtime.etypelink", 0).Sect = sect
	for ; s != nil && s.Type == obj.STYPELINK; s = s.Next {
		datsize = aligndatsize(datsize, s)
		s.Sect = sect
		s.Type = obj.SRODATA
		s.Value = int64(uint64(datsize) - sect.Vaddr)
		growdatsize(&datsize, s)
	}

	sect.Length = uint64(datsize) - sect.Vaddr

	/* gosymtab */
	sect = addsection(segro, relro_prefix+".gosymtab", relro_perms)

	sect.Align = maxalign(s, obj.SPCLNTAB-1)
	datsize = Rnd(datsize, int64(sect.Align))
	sect.Vaddr = uint64(datsize)
	Linklookup(Ctxt, "runtime.symtab", 0).Sect = sect
	Linklookup(Ctxt, "runtime.esymtab", 0).Sect = sect
	for ; s != nil && s.Type < obj.SPCLNTAB; s = s.Next {
		datsize = aligndatsize(datsize, s)
		s.Sect = sect
		s.Type = obj.SRODATA
		s.Value = int64(uint64(datsize) - sect.Vaddr)
		growdatsize(&datsize, s)
	}

	sect.Length = uint64(datsize) - sect.Vaddr

	/* gopclntab */
	sect = addsection(segro, relro_prefix+".gopclntab", relro_perms)

	sect.Align = maxalign(s, obj.SELFROSECT-1)
	datsize = Rnd(datsize, int64(sect.Align))
	sect.Vaddr = uint64(datsize)
	Linklookup(Ctxt, "runtime.pclntab", 0).Sect = sect
	Linklookup(Ctxt, "runtime.epclntab", 0).Sect = sect
	for ; s != nil && s.Type < obj.SELFROSECT; s = s.Next {
		datsize = aligndatsize(datsize, s)
		s.Sect = sect
		s.Type = obj.SRODATA
		s.Value = int64(uint64(datsize) - sect.Vaddr)
		growdatsize(&datsize, s)
	}

	sect.Length = uint64(datsize) - sect.Vaddr

	/* read-only ELF, Mach-O sections */
	for ; s != nil && s.Type < obj.SELFSECT; s = s.Next {
		sect = addsection(segro, s.Name, 04)
		sect.Align = symalign(s)
		datsize = Rnd(datsize, int64(sect.Align))
		sect.Vaddr = uint64(datsize)
		s.Sect = sect
		s.Type = obj.SRODATA
		s.Value = int64(uint64(datsize) - sect.Vaddr)
		growdatsize(&datsize, s)
		sect.Length = uint64(datsize) - sect.Vaddr
	}

	// 6g uses 4-byte relocation offsets, so the entire segment must fit in 32 bits.
	if datsize != int64(uint32(datsize)) {
		Diag("read-only data segment too large")
	}

	/* number the sections */
	n := int32(1)

	for sect := Segtext.Sect; sect != nil; sect = sect.Next {
		sect.Extnum = int16(n)
		n++
	}
	for sect := Segrodata.Sect; sect != nil; sect = sect.Next {
		sect.Extnum = int16(n)
		n++
	}
	for sect := Segdata.Sect; sect != nil; sect = sect.Next {
		sect.Extnum = int16(n)
		n++
	}
}