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Source file src/cmd/link/internal/arm64/asm.go

Documentation: cmd/link/internal/arm64

  // Inferno utils/5l/asm.c
  // https://bitbucket.org/inferno-os/inferno-os/src/default/utils/5l/asm.c
  //
  //	Copyright © 1994-1999 Lucent Technologies Inc.  All rights reserved.
  //	Portions Copyright © 1995-1997 C H Forsyth (forsyth@terzarima.net)
  //	Portions Copyright © 1997-1999 Vita Nuova Limited
  //	Portions Copyright © 2000-2007 Vita Nuova Holdings Limited (www.vitanuova.com)
  //	Portions Copyright © 2004,2006 Bruce Ellis
  //	Portions Copyright © 2005-2007 C H Forsyth (forsyth@terzarima.net)
  //	Revisions Copyright © 2000-2007 Lucent Technologies Inc. and others
  //	Portions Copyright © 2009 The Go Authors. All rights reserved.
  //
  // Permission is hereby granted, free of charge, to any person obtaining a copy
  // of this software and associated documentation files (the "Software"), to deal
  // in the Software without restriction, including without limitation the rights
  // to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
  // copies of the Software, and to permit persons to whom the Software is
  // furnished to do so, subject to the following conditions:
  //
  // The above copyright notice and this permission notice shall be included in
  // all copies or substantial portions of the Software.
  //
  // THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  // IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  // FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL THE
  // AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  // LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
  // OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
  // THE SOFTWARE.
  
  package arm64
  
  import (
  	"cmd/internal/objabi"
  	"cmd/link/internal/ld"
  	"encoding/binary"
  	"fmt"
  	"log"
  )
  
  func gentext(ctxt *ld.Link) {
  	if !ctxt.DynlinkingGo() {
  		return
  	}
  	addmoduledata := ctxt.Syms.Lookup("runtime.addmoduledata", 0)
  	if addmoduledata.Type == ld.STEXT {
  		// we're linking a module containing the runtime -> no need for
  		// an init function
  		return
  	}
  	addmoduledata.Attr |= ld.AttrReachable
  	initfunc := ctxt.Syms.Lookup("go.link.addmoduledata", 0)
  	initfunc.Type = ld.STEXT
  	initfunc.Attr |= ld.AttrLocal
  	initfunc.Attr |= ld.AttrReachable
  	o := func(op uint32) {
  		ld.Adduint32(ctxt, initfunc, op)
  	}
  	// 0000000000000000 <local.dso_init>:
  	// 0:	90000000 	adrp	x0, 0 <runtime.firstmoduledata>
  	// 	0: R_AARCH64_ADR_PREL_PG_HI21	local.moduledata
  	// 4:	91000000 	add	x0, x0, #0x0
  	// 	4: R_AARCH64_ADD_ABS_LO12_NC	local.moduledata
  	o(0x90000000)
  	o(0x91000000)
  	rel := ld.Addrel(initfunc)
  	rel.Off = 0
  	rel.Siz = 8
  	rel.Sym = ctxt.Moduledata
  	rel.Type = objabi.R_ADDRARM64
  
  	// 8:	14000000 	bl	0 <runtime.addmoduledata>
  	// 	8: R_AARCH64_CALL26	runtime.addmoduledata
  	o(0x14000000)
  	rel = ld.Addrel(initfunc)
  	rel.Off = 8
  	rel.Siz = 4
  	rel.Sym = ctxt.Syms.Lookup("runtime.addmoduledata", 0)
  	rel.Type = objabi.R_CALLARM64 // Really should be R_AARCH64_JUMP26 but doesn't seem to make any difference
  
  	ctxt.Textp = append(ctxt.Textp, initfunc)
  	initarray_entry := ctxt.Syms.Lookup("go.link.addmoduledatainit", 0)
  	initarray_entry.Attr |= ld.AttrReachable
  	initarray_entry.Attr |= ld.AttrLocal
  	initarray_entry.Type = ld.SINITARR
  	ld.Addaddr(ctxt, initarray_entry, initfunc)
  }
  
  func adddynrel(ctxt *ld.Link, s *ld.Symbol, r *ld.Reloc) bool {
  	log.Fatalf("adddynrel not implemented")
  	return false
  }
  
  func elfreloc1(ctxt *ld.Link, r *ld.Reloc, sectoff int64) int {
  	ld.Thearch.Vput(uint64(sectoff))
  
  	elfsym := r.Xsym.ElfsymForReloc()
  	switch r.Type {
  	default:
  		return -1
  
  	case objabi.R_ADDR:
  		switch r.Siz {
  		case 4:
  			ld.Thearch.Vput(ld.R_AARCH64_ABS32 | uint64(elfsym)<<32)
  		case 8:
  			ld.Thearch.Vput(ld.R_AARCH64_ABS64 | uint64(elfsym)<<32)
  		default:
  			return -1
  		}
  
  	case objabi.R_ADDRARM64:
  		// two relocations: R_AARCH64_ADR_PREL_PG_HI21 and R_AARCH64_ADD_ABS_LO12_NC
  		ld.Thearch.Vput(ld.R_AARCH64_ADR_PREL_PG_HI21 | uint64(elfsym)<<32)
  		ld.Thearch.Vput(uint64(r.Xadd))
  		ld.Thearch.Vput(uint64(sectoff + 4))
  		ld.Thearch.Vput(ld.R_AARCH64_ADD_ABS_LO12_NC | uint64(elfsym)<<32)
  
  	case objabi.R_ARM64_TLS_LE:
  		ld.Thearch.Vput(ld.R_AARCH64_TLSLE_MOVW_TPREL_G0 | uint64(elfsym)<<32)
  
  	case objabi.R_ARM64_TLS_IE:
  		ld.Thearch.Vput(ld.R_AARCH64_TLSIE_ADR_GOTTPREL_PAGE21 | uint64(elfsym)<<32)
  		ld.Thearch.Vput(uint64(r.Xadd))
  		ld.Thearch.Vput(uint64(sectoff + 4))
  		ld.Thearch.Vput(ld.R_AARCH64_TLSIE_LD64_GOTTPREL_LO12_NC | uint64(elfsym)<<32)
  
  	case objabi.R_ARM64_GOTPCREL:
  		ld.Thearch.Vput(ld.R_AARCH64_ADR_GOT_PAGE | uint64(elfsym)<<32)
  		ld.Thearch.Vput(uint64(r.Xadd))
  		ld.Thearch.Vput(uint64(sectoff + 4))
  		ld.Thearch.Vput(ld.R_AARCH64_LD64_GOT_LO12_NC | uint64(elfsym)<<32)
  
  	case objabi.R_CALLARM64:
  		if r.Siz != 4 {
  			return -1
  		}
  		ld.Thearch.Vput(ld.R_AARCH64_CALL26 | uint64(elfsym)<<32)
  
  	}
  	ld.Thearch.Vput(uint64(r.Xadd))
  
  	return 0
  }
  
  func elfsetupplt(ctxt *ld.Link) {
  	// TODO(aram)
  	return
  }
  
  func machoreloc1(s *ld.Symbol, r *ld.Reloc, sectoff int64) int {
  	var v uint32
  
  	rs := r.Xsym
  
  	// ld64 has a bug handling MACHO_ARM64_RELOC_UNSIGNED with !extern relocation.
  	// see cmd/internal/ld/data.go for details. The workaround is that don't use !extern
  	// UNSIGNED relocation at all.
  	if rs.Type == ld.SHOSTOBJ || r.Type == objabi.R_CALLARM64 || r.Type == objabi.R_ADDRARM64 || r.Type == objabi.R_ADDR {
  		if rs.Dynid < 0 {
  			ld.Errorf(s, "reloc %d to non-macho symbol %s type=%d", r.Type, rs.Name, rs.Type)
  			return -1
  		}
  
  		v = uint32(rs.Dynid)
  		v |= 1 << 27 // external relocation
  	} else {
  		v = uint32(rs.Sect.Extnum)
  		if v == 0 {
  			ld.Errorf(s, "reloc %d to symbol %s in non-macho section %s type=%d", r.Type, rs.Name, rs.Sect.Name, rs.Type)
  			return -1
  		}
  	}
  
  	switch r.Type {
  	default:
  		return -1
  
  	case objabi.R_ADDR:
  		v |= ld.MACHO_ARM64_RELOC_UNSIGNED << 28
  
  	case objabi.R_CALLARM64:
  		if r.Xadd != 0 {
  			ld.Errorf(s, "ld64 doesn't allow BR26 reloc with non-zero addend: %s+%d", rs.Name, r.Xadd)
  		}
  
  		v |= 1 << 24 // pc-relative bit
  		v |= ld.MACHO_ARM64_RELOC_BRANCH26 << 28
  
  	case objabi.R_ADDRARM64:
  		r.Siz = 4
  		// Two relocation entries: MACHO_ARM64_RELOC_PAGEOFF12 MACHO_ARM64_RELOC_PAGE21
  		// if r.Xadd is non-zero, add two MACHO_ARM64_RELOC_ADDEND.
  		if r.Xadd != 0 {
  			ld.Thearch.Lput(uint32(sectoff + 4))
  			ld.Thearch.Lput((ld.MACHO_ARM64_RELOC_ADDEND << 28) | (2 << 25) | uint32(r.Xadd&0xffffff))
  		}
  		ld.Thearch.Lput(uint32(sectoff + 4))
  		ld.Thearch.Lput(v | (ld.MACHO_ARM64_RELOC_PAGEOFF12 << 28) | (2 << 25))
  		if r.Xadd != 0 {
  			ld.Thearch.Lput(uint32(sectoff))
  			ld.Thearch.Lput((ld.MACHO_ARM64_RELOC_ADDEND << 28) | (2 << 25) | uint32(r.Xadd&0xffffff))
  		}
  		v |= 1 << 24 // pc-relative bit
  		v |= ld.MACHO_ARM64_RELOC_PAGE21 << 28
  	}
  
  	switch r.Siz {
  	default:
  		return -1
  
  	case 1:
  		v |= 0 << 25
  
  	case 2:
  		v |= 1 << 25
  
  	case 4:
  		v |= 2 << 25
  
  	case 8:
  		v |= 3 << 25
  	}
  
  	ld.Thearch.Lput(uint32(sectoff))
  	ld.Thearch.Lput(v)
  	return 0
  }
  
  func archreloc(ctxt *ld.Link, r *ld.Reloc, s *ld.Symbol, val *int64) int {
  	if ld.Linkmode == ld.LinkExternal {
  		switch r.Type {
  		default:
  			return -1
  
  		case objabi.R_ARM64_GOTPCREL:
  			var o1, o2 uint32
  			if ctxt.Arch.ByteOrder == binary.BigEndian {
  				o1 = uint32(*val >> 32)
  				o2 = uint32(*val)
  			} else {
  				o1 = uint32(*val)
  				o2 = uint32(*val >> 32)
  			}
  			// Any relocation against a function symbol is redirected to
  			// be against a local symbol instead (see putelfsym in
  			// symtab.go) but unfortunately the system linker was buggy
  			// when confronted with a R_AARCH64_ADR_GOT_PAGE relocation
  			// against a local symbol until May 2015
  			// (https://sourceware.org/bugzilla/show_bug.cgi?id=18270). So
  			// we convert the adrp; ld64 + R_ARM64_GOTPCREL into adrp;
  			// add + R_ADDRARM64.
  			if !(r.Sym.Version != 0 || (r.Sym.Type&ld.SHIDDEN != 0) || r.Sym.Attr.Local()) && r.Sym.Type == ld.STEXT && ctxt.DynlinkingGo() {
  				if o2&0xffc00000 != 0xf9400000 {
  					ld.Errorf(s, "R_ARM64_GOTPCREL against unexpected instruction %x", o2)
  				}
  				o2 = 0x91000000 | (o2 & 0x000003ff)
  				r.Type = objabi.R_ADDRARM64
  			}
  			if ctxt.Arch.ByteOrder == binary.BigEndian {
  				*val = int64(o1)<<32 | int64(o2)
  			} else {
  				*val = int64(o2)<<32 | int64(o1)
  			}
  			fallthrough
  
  		case objabi.R_ADDRARM64:
  			r.Done = 0
  
  			// set up addend for eventual relocation via outer symbol.
  			rs := r.Sym
  			r.Xadd = r.Add
  			for rs.Outer != nil {
  				r.Xadd += ld.Symaddr(rs) - ld.Symaddr(rs.Outer)
  				rs = rs.Outer
  			}
  
  			if rs.Type != ld.SHOSTOBJ && rs.Type != ld.SDYNIMPORT && rs.Sect == nil {
  				ld.Errorf(s, "missing section for %s", rs.Name)
  			}
  			r.Xsym = rs
  
  			// Note: ld64 currently has a bug that any non-zero addend for BR26 relocation
  			// will make the linking fail because it thinks the code is not PIC even though
  			// the BR26 relocation should be fully resolved at link time.
  			// That is the reason why the next if block is disabled. When the bug in ld64
  			// is fixed, we can enable this block and also enable duff's device in cmd/7g.
  			if false && ld.Headtype == objabi.Hdarwin {
  				var o0, o1 uint32
  
  				if ctxt.Arch.ByteOrder == binary.BigEndian {
  					o0 = uint32(*val >> 32)
  					o1 = uint32(*val)
  				} else {
  					o0 = uint32(*val)
  					o1 = uint32(*val >> 32)
  				}
  				// Mach-O wants the addend to be encoded in the instruction
  				// Note that although Mach-O supports ARM64_RELOC_ADDEND, it
  				// can only encode 24-bit of signed addend, but the instructions
  				// supports 33-bit of signed addend, so we always encode the
  				// addend in place.
  				o0 |= (uint32((r.Xadd>>12)&3) << 29) | (uint32((r.Xadd>>12>>2)&0x7ffff) << 5)
  				o1 |= uint32(r.Xadd&0xfff) << 10
  				r.Xadd = 0
  
  				// when laid out, the instruction order must always be o1, o2.
  				if ctxt.Arch.ByteOrder == binary.BigEndian {
  					*val = int64(o0)<<32 | int64(o1)
  				} else {
  					*val = int64(o1)<<32 | int64(o0)
  				}
  			}
  
  			return 0
  
  		case objabi.R_CALLARM64,
  			objabi.R_ARM64_TLS_LE,
  			objabi.R_ARM64_TLS_IE:
  			r.Done = 0
  			r.Xsym = r.Sym
  			r.Xadd = r.Add
  			return 0
  		}
  	}
  
  	switch r.Type {
  	case objabi.R_CONST:
  		*val = r.Add
  		return 0
  
  	case objabi.R_GOTOFF:
  		*val = ld.Symaddr(r.Sym) + r.Add - ld.Symaddr(ctxt.Syms.Lookup(".got", 0))
  		return 0
  
  	case objabi.R_ADDRARM64:
  		t := ld.Symaddr(r.Sym) + r.Add - ((s.Value + int64(r.Off)) &^ 0xfff)
  		if t >= 1<<32 || t < -1<<32 {
  			ld.Errorf(s, "program too large, address relocation distance = %d", t)
  		}
  
  		var o0, o1 uint32
  
  		if ctxt.Arch.ByteOrder == binary.BigEndian {
  			o0 = uint32(*val >> 32)
  			o1 = uint32(*val)
  		} else {
  			o0 = uint32(*val)
  			o1 = uint32(*val >> 32)
  		}
  
  		o0 |= (uint32((t>>12)&3) << 29) | (uint32((t>>12>>2)&0x7ffff) << 5)
  		o1 |= uint32(t&0xfff) << 10
  
  		// when laid out, the instruction order must always be o1, o2.
  		if ctxt.Arch.ByteOrder == binary.BigEndian {
  			*val = int64(o0)<<32 | int64(o1)
  		} else {
  			*val = int64(o1)<<32 | int64(o0)
  		}
  		return 0
  
  	case objabi.R_ARM64_TLS_LE:
  		r.Done = 0
  		if ld.Headtype != objabi.Hlinux {
  			ld.Errorf(s, "TLS reloc on unsupported OS %v", ld.Headtype)
  		}
  		// The TCB is two pointers. This is not documented anywhere, but is
  		// de facto part of the ABI.
  		v := r.Sym.Value + int64(2*ld.SysArch.PtrSize)
  		if v < 0 || v >= 32678 {
  			ld.Errorf(s, "TLS offset out of range %d", v)
  		}
  		*val |= v << 5
  		return 0
  
  	case objabi.R_CALLARM64:
  		t := (ld.Symaddr(r.Sym) + r.Add) - (s.Value + int64(r.Off))
  		if t >= 1<<27 || t < -1<<27 {
  			ld.Errorf(s, "program too large, call relocation distance = %d", t)
  		}
  		*val |= (t >> 2) & 0x03ffffff
  		return 0
  	}
  
  	return -1
  }
  
  func archrelocvariant(ctxt *ld.Link, r *ld.Reloc, s *ld.Symbol, t int64) int64 {
  	log.Fatalf("unexpected relocation variant")
  	return -1
  }
  
  func asmb(ctxt *ld.Link) {
  	if ctxt.Debugvlog != 0 {
  		ctxt.Logf("%5.2f asmb\n", ld.Cputime())
  	}
  
  	if ld.Iself {
  		ld.Asmbelfsetup()
  	}
  
  	sect := ld.Segtext.Sections[0]
  	ld.Cseek(int64(sect.Vaddr - ld.Segtext.Vaddr + ld.Segtext.Fileoff))
  	ld.Codeblk(ctxt, int64(sect.Vaddr), int64(sect.Length))
  	for _, sect = range ld.Segtext.Sections[1:] {
  		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", ld.Cputime())
  		}
  		ld.Cseek(int64(ld.Segrodata.Fileoff))
  		ld.Datblk(ctxt, int64(ld.Segrodata.Vaddr), int64(ld.Segrodata.Filelen))
  	}
  	if ld.Segrelrodata.Filelen > 0 {
  		if ctxt.Debugvlog != 0 {
  			ctxt.Logf("%5.2f relrodatblk\n", ld.Cputime())
  		}
  		ld.Cseek(int64(ld.Segrelrodata.Fileoff))
  		ld.Datblk(ctxt, int64(ld.Segrelrodata.Vaddr), int64(ld.Segrelrodata.Filelen))
  	}
  
  	if ctxt.Debugvlog != 0 {
  		ctxt.Logf("%5.2f datblk\n", ld.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))
  
  	machlink := uint32(0)
  	if ld.Headtype == objabi.Hdarwin {
  		machlink = uint32(ld.Domacholink(ctxt))
  	}
  
  	/* 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", ld.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 objabi.Hplan9:
  			symo = uint32(ld.Segdata.Fileoff + ld.Segdata.Filelen)
  
  		case objabi.Hdarwin:
  			symo = uint32(ld.Segdwarf.Fileoff + uint64(ld.Rnd(int64(ld.Segdwarf.Filelen), int64(*ld.FlagRound))) + uint64(machlink))
  		}
  
  		ld.Cseek(int64(symo))
  		switch ld.Headtype {
  		default:
  			if ld.Iself {
  				if ctxt.Debugvlog != 0 {
  					ctxt.Logf("%5.2f elfsym\n", ld.Cputime())
  				}
  				ld.Asmelfsym(ctxt)
  				ld.Cflush()
  				ld.Cwrite(ld.Elfstrdat)
  
  				if ld.Linkmode == ld.LinkExternal {
  					ld.Elfemitreloc(ctxt)
  				}
  			}
  
  		case objabi.Hplan9:
  			ld.Asmplan9sym(ctxt)
  			ld.Cflush()
  
  			sym := ctxt.Syms.Lookup("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 objabi.Hdarwin:
  			if ld.Linkmode == ld.LinkExternal {
  				ld.Machoemitreloc(ctxt)
  			}
  		}
  	}
  
  	if ctxt.Debugvlog != 0 {
  		ctxt.Logf("%5.2f header\n", ld.Cputime())
  	}
  	ld.Cseek(0)
  	switch ld.Headtype {
  	default:
  	case objabi.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(ctxt))) /* va of entry */
  		ld.Thearch.Lput(0)
  		ld.Thearch.Lput(uint32(ld.Lcsize))
  
  	case objabi.Hlinux,
  		objabi.Hfreebsd,
  		objabi.Hnetbsd,
  		objabi.Hopenbsd,
  		objabi.Hnacl:
  		ld.Asmbelf(ctxt, int64(symo))
  
  	case objabi.Hdarwin:
  		ld.Asmbmacho(ctxt)
  	}
  
  	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))
  	}
  }
  

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