Adding upstream version 1.16.10.upstream/1.16.10upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

3 files changed, 651 insertions, 0 deletions

diff --git a/src/cmd/link/internal/x86/asm.go b/src/cmd/link/internal/x86/asm.go
new file mode 100644
index 0000000..af0ce11
--- /dev/null
+++ b/src/cmd/link/internal/x86/asm.go
@@ -0,0 +1,492 @@
+// Inferno utils/8l/asm.c
+// https://bitbucket.org/inferno-os/inferno-os/src/master/utils/8l/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 x86
+
+import (
+	"cmd/internal/objabi"
+	"cmd/internal/sys"
+	"cmd/link/internal/ld"
+	"cmd/link/internal/loader"
+	"cmd/link/internal/sym"
+	"debug/elf"
+	"log"
+)
+
+func gentext(ctxt *ld.Link, ldr *loader.Loader) {
+	if ctxt.DynlinkingGo() {
+		// We need get_pc_thunk.
+	} else {
+		switch ctxt.BuildMode {
+		case ld.BuildModeCArchive:
+			if !ctxt.IsELF {
+				return
+			}
+		case ld.BuildModePIE, ld.BuildModeCShared, ld.BuildModePlugin:
+			// We need get_pc_thunk.
+		default:
+			return
+		}
+	}
+
+	// Generate little thunks that load the PC of the next instruction into a register.
+	thunks := make([]loader.Sym, 0, 7+len(ctxt.Textp))
+	for _, r := range [...]struct {
+		name string
+		num  uint8
+	}{
+		{"ax", 0},
+		{"cx", 1},
+		{"dx", 2},
+		{"bx", 3},
+		// sp
+		{"bp", 5},
+		{"si", 6},
+		{"di", 7},
+	} {
+		thunkfunc := ldr.CreateSymForUpdate("__x86.get_pc_thunk."+r.name, 0)
+		thunkfunc.SetType(sym.STEXT)
+		ldr.SetAttrLocal(thunkfunc.Sym(), true)
+		o := func(op ...uint8) {
+			for _, op1 := range op {
+				thunkfunc.AddUint8(op1)
+			}
+		}
+		// 8b 04 24	mov    (%esp),%eax
+		// Destination register is in bits 3-5 of the middle byte, so add that in.
+		o(0x8b, 0x04+r.num<<3, 0x24)
+		// c3		ret
+		o(0xc3)
+
+		thunks = append(thunks, thunkfunc.Sym())
+	}
+	ctxt.Textp = append(thunks, ctxt.Textp...) // keep Textp in dependency order
+
+	initfunc, addmoduledata := ld.PrepareAddmoduledata(ctxt)
+	if initfunc == nil {
+		return
+	}
+
+	o := func(op ...uint8) {
+		for _, op1 := range op {
+			initfunc.AddUint8(op1)
+		}
+	}
+
+	// go.link.addmoduledata:
+	//      53                      push %ebx
+	//      e8 00 00 00 00          call __x86.get_pc_thunk.cx + R_CALL __x86.get_pc_thunk.cx
+	//      8d 81 00 00 00 00       lea 0x0(%ecx), %eax + R_PCREL ctxt.Moduledata
+	//      8d 99 00 00 00 00       lea 0x0(%ecx), %ebx + R_GOTPC _GLOBAL_OFFSET_TABLE_
+	//      e8 00 00 00 00          call runtime.addmoduledata@plt + R_CALL runtime.addmoduledata
+	//      5b                      pop %ebx
+	//      c3                      ret
+
+	o(0x53)
+
+	o(0xe8)
+	initfunc.AddSymRef(ctxt.Arch, ldr.Lookup("__x86.get_pc_thunk.cx", 0), 0, objabi.R_CALL, 4)
+
+	o(0x8d, 0x81)
+	initfunc.AddPCRelPlus(ctxt.Arch, ctxt.Moduledata, 6)
+
+	o(0x8d, 0x99)
+	gotsym := ldr.LookupOrCreateSym("_GLOBAL_OFFSET_TABLE_", 0)
+	initfunc.AddSymRef(ctxt.Arch, gotsym, 12, objabi.R_PCREL, 4)
+	o(0xe8)
+	initfunc.AddSymRef(ctxt.Arch, addmoduledata, 0, objabi.R_CALL, 4)
+
+	o(0x5b)
+
+	o(0xc3)
+}
+
+func adddynrel(target *ld.Target, ldr *loader.Loader, syms *ld.ArchSyms, s loader.Sym, r loader.Reloc, rIdx int) bool {
+	targ := r.Sym()
+	var targType sym.SymKind
+	if targ != 0 {
+		targType = ldr.SymType(targ)
+	}
+
+	switch r.Type() {
+	default:
+		if r.Type() >= objabi.ElfRelocOffset {
+			ldr.Errorf(s, "unexpected relocation type %d (%s)", r.Type(), sym.RelocName(target.Arch, r.Type()))
+			return false
+		}
+
+		// Handle relocations found in ELF object files.
+	case objabi.ElfRelocOffset + objabi.RelocType(elf.R_386_PC32):
+		if targType == sym.SDYNIMPORT {
+			ldr.Errorf(s, "unexpected R_386_PC32 relocation for dynamic symbol %s", ldr.SymName(targ))
+		}
+		// TODO(mwhudson): the test of VisibilityHidden here probably doesn't make
+		// sense and should be removed when someone has thought about it properly.
+		if (targType == 0 || targType == sym.SXREF) && !ldr.AttrVisibilityHidden(targ) {
+			ldr.Errorf(s, "unknown symbol %s in pcrel", ldr.SymName(targ))
+		}
+		su := ldr.MakeSymbolUpdater(s)
+		su.SetRelocType(rIdx, objabi.R_PCREL)
+		su.SetRelocAdd(rIdx, r.Add()+4)
+		return true
+
+	case objabi.ElfRelocOffset + objabi.RelocType(elf.R_386_PLT32):
+		su := ldr.MakeSymbolUpdater(s)
+		su.SetRelocType(rIdx, objabi.R_PCREL)
+		su.SetRelocAdd(rIdx, r.Add()+4)
+		if targType == sym.SDYNIMPORT {
+			addpltsym(target, ldr, syms, targ)
+			su.SetRelocSym(rIdx, syms.PLT)
+			su.SetRelocAdd(rIdx, r.Add()+int64(ldr.SymPlt(targ)))
+		}
+
+		return true
+
+	case objabi.ElfRelocOffset + objabi.RelocType(elf.R_386_GOT32),
+		objabi.ElfRelocOffset + objabi.RelocType(elf.R_386_GOT32X):
+		su := ldr.MakeSymbolUpdater(s)
+		if targType != sym.SDYNIMPORT {
+			// have symbol
+			sData := ldr.Data(s)
+
+			if r.Off() >= 2 && sData[r.Off()-2] == 0x8b {
+				su.MakeWritable()
+
+				// turn MOVL of GOT entry into LEAL of symbol address, relative to GOT.
+				writeableData := su.Data()
+				writeableData[r.Off()-2] = 0x8d
+				su.SetRelocType(rIdx, objabi.R_GOTOFF)
+				return true
+			}
+
+			if r.Off() >= 2 && sData[r.Off()-2] == 0xff && sData[r.Off()-1] == 0xb3 {
+				su.MakeWritable()
+				// turn PUSHL of GOT entry into PUSHL of symbol itself.
+				// use unnecessary SS prefix to keep instruction same length.
+				writeableData := su.Data()
+				writeableData[r.Off()-2] = 0x36
+				writeableData[r.Off()-1] = 0x68
+				su.SetRelocType(rIdx, objabi.R_ADDR)
+				return true
+			}
+
+			ldr.Errorf(s, "unexpected GOT reloc for non-dynamic symbol %s", ldr.SymName(targ))
+			return false
+		}
+
+		ld.AddGotSym(target, ldr, syms, targ, uint32(elf.R_386_GLOB_DAT))
+		su.SetRelocType(rIdx, objabi.R_CONST) // write r->add during relocsym
+		su.SetRelocSym(rIdx, 0)
+		su.SetRelocAdd(rIdx, r.Add()+int64(ldr.SymGot(targ)))
+		return true
+
+	case objabi.ElfRelocOffset + objabi.RelocType(elf.R_386_GOTOFF):
+		su := ldr.MakeSymbolUpdater(s)
+		su.SetRelocType(rIdx, objabi.R_GOTOFF)
+		return true
+
+	case objabi.ElfRelocOffset + objabi.RelocType(elf.R_386_GOTPC):
+		su := ldr.MakeSymbolUpdater(s)
+		su.SetRelocType(rIdx, objabi.R_PCREL)
+		su.SetRelocSym(rIdx, syms.GOT)
+		su.SetRelocAdd(rIdx, r.Add()+4)
+		return true
+
+	case objabi.ElfRelocOffset + objabi.RelocType(elf.R_386_32):
+		if targType == sym.SDYNIMPORT {
+			ldr.Errorf(s, "unexpected R_386_32 relocation for dynamic symbol %s", ldr.SymName(targ))
+		}
+		su := ldr.MakeSymbolUpdater(s)
+		su.SetRelocType(rIdx, objabi.R_ADDR)
+		return true
+
+	case objabi.MachoRelocOffset + ld.MACHO_GENERIC_RELOC_VANILLA*2 + 0:
+		su := ldr.MakeSymbolUpdater(s)
+		su.SetRelocType(rIdx, objabi.R_ADDR)
+		if targType == sym.SDYNIMPORT {
+			ldr.Errorf(s, "unexpected reloc for dynamic symbol %s", ldr.SymName(targ))
+		}
+		return true
+
+	case objabi.MachoRelocOffset + ld.MACHO_GENERIC_RELOC_VANILLA*2 + 1:
+		su := ldr.MakeSymbolUpdater(s)
+		if targType == sym.SDYNIMPORT {
+			addpltsym(target, ldr, syms, targ)
+			su.SetRelocSym(rIdx, syms.PLT)
+			su.SetRelocAdd(rIdx, int64(ldr.SymPlt(targ)))
+			su.SetRelocType(rIdx, objabi.R_PCREL)
+			return true
+		}
+
+		su.SetRelocType(rIdx, objabi.R_PCREL)
+		return true
+
+	case objabi.MachoRelocOffset + ld.MACHO_FAKE_GOTPCREL:
+		su := ldr.MakeSymbolUpdater(s)
+		if targType != sym.SDYNIMPORT {
+			// have symbol
+			// turn MOVL of GOT entry into LEAL of symbol itself
+			sData := ldr.Data(s)
+			if r.Off() < 2 || sData[r.Off()-2] != 0x8b {
+				ldr.Errorf(s, "unexpected GOT reloc for non-dynamic symbol %s", ldr.SymName(targ))
+				return false
+			}
+
+			su.MakeWritable()
+			writeableData := su.Data()
+			writeableData[r.Off()-2] = 0x8d
+			su.SetRelocType(rIdx, objabi.R_PCREL)
+			return true
+		}
+
+		ld.AddGotSym(target, ldr, syms, targ, uint32(elf.R_386_GLOB_DAT))
+		su.SetRelocSym(rIdx, syms.GOT)
+		su.SetRelocAdd(rIdx, r.Add()+int64(ldr.SymGot(targ)))
+		su.SetRelocType(rIdx, objabi.R_PCREL)
+		return true
+	}
+
+	// Handle references to ELF symbols from our own object files.
+	if targType != sym.SDYNIMPORT {
+		return true
+	}
+
+	// Reread the reloc to incorporate any changes in type above.
+	relocs := ldr.Relocs(s)
+	r = relocs.At(rIdx)
+
+	switch r.Type() {
+	case objabi.R_CALL,
+		objabi.R_PCREL:
+		if target.IsExternal() {
+			// External linker will do this relocation.
+			return true
+		}
+		addpltsym(target, ldr, syms, targ)
+		su := ldr.MakeSymbolUpdater(s)
+		su.SetRelocSym(rIdx, syms.PLT)
+		su.SetRelocAdd(rIdx, int64(ldr.SymPlt(targ)))
+		return true
+
+	case objabi.R_ADDR:
+		if ldr.SymType(s) != sym.SDATA {
+			break
+		}
+		if target.IsElf() {
+			ld.Adddynsym(ldr, target, syms, targ)
+			rel := ldr.MakeSymbolUpdater(syms.Rel)
+			rel.AddAddrPlus(target.Arch, s, int64(r.Off()))
+			rel.AddUint32(target.Arch, elf.R_INFO32(uint32(ldr.SymDynid(targ)), uint32(elf.R_386_32)))
+			su := ldr.MakeSymbolUpdater(s)
+			su.SetRelocType(rIdx, objabi.R_CONST) // write r->add during relocsym
+			su.SetRelocSym(rIdx, 0)
+			return true
+		}
+	}
+
+	return false
+}
+
+func elfreloc1(ctxt *ld.Link, out *ld.OutBuf, ldr *loader.Loader, s loader.Sym, r loader.ExtReloc, ri int, sectoff int64) bool {
+	out.Write32(uint32(sectoff))
+
+	elfsym := ld.ElfSymForReloc(ctxt, r.Xsym)
+	siz := r.Size
+	switch r.Type {
+	default:
+		return false
+	case objabi.R_ADDR, objabi.R_DWARFSECREF:
+		if siz == 4 {
+			out.Write32(uint32(elf.R_386_32) | uint32(elfsym)<<8)
+		} else {
+			return false
+		}
+	case objabi.R_GOTPCREL:
+		if siz == 4 {
+			out.Write32(uint32(elf.R_386_GOTPC))
+			if ldr.SymName(r.Xsym) != "_GLOBAL_OFFSET_TABLE_" {
+				out.Write32(uint32(sectoff))
+				out.Write32(uint32(elf.R_386_GOT32) | uint32(elfsym)<<8)
+			}
+		} else {
+			return false
+		}
+	case objabi.R_CALL:
+		if siz == 4 {
+			if ldr.SymType(r.Xsym) == sym.SDYNIMPORT {
+				out.Write32(uint32(elf.R_386_PLT32) | uint32(elfsym)<<8)
+			} else {
+				out.Write32(uint32(elf.R_386_PC32) | uint32(elfsym)<<8)
+			}
+		} else {
+			return false
+		}
+	case objabi.R_PCREL:
+		if siz == 4 {
+			out.Write32(uint32(elf.R_386_PC32) | uint32(elfsym)<<8)
+		} else {
+			return false
+		}
+	case objabi.R_TLS_LE:
+		if siz == 4 {
+			out.Write32(uint32(elf.R_386_TLS_LE) | uint32(elfsym)<<8)
+		} else {
+			return false
+		}
+	case objabi.R_TLS_IE:
+		if siz == 4 {
+			out.Write32(uint32(elf.R_386_GOTPC))
+			out.Write32(uint32(sectoff))
+			out.Write32(uint32(elf.R_386_TLS_GOTIE) | uint32(elfsym)<<8)
+		} else {
+			return false
+		}
+	}
+
+	return true
+}
+
+func machoreloc1(*sys.Arch, *ld.OutBuf, *loader.Loader, loader.Sym, loader.ExtReloc, int64) bool {
+	return false
+}
+
+func pereloc1(arch *sys.Arch, out *ld.OutBuf, ldr *loader.Loader, s loader.Sym, r loader.ExtReloc, sectoff int64) bool {
+	var v uint32
+
+	rs := r.Xsym
+	rt := r.Type
+
+	if ldr.SymDynid(rs) < 0 {
+		ldr.Errorf(s, "reloc %d (%s) to non-coff symbol %s type=%d (%s)", rt, sym.RelocName(arch, rt), ldr.SymName(rs), ldr.SymType(rs), ldr.SymType(rs))
+		return false
+	}
+
+	out.Write32(uint32(sectoff))
+	out.Write32(uint32(ldr.SymDynid(rs)))
+
+	switch rt {
+	default:
+		return false
+
+	case objabi.R_DWARFSECREF:
+		v = ld.IMAGE_REL_I386_SECREL
+
+	case objabi.R_ADDR:
+		v = ld.IMAGE_REL_I386_DIR32
+
+	case objabi.R_CALL,
+		objabi.R_PCREL:
+		v = ld.IMAGE_REL_I386_REL32
+	}
+
+	out.Write16(uint16(v))
+
+	return true
+}
+
+func archreloc(*ld.Target, *loader.Loader, *ld.ArchSyms, loader.Reloc, loader.Sym, int64) (int64, int, bool) {
+	return -1, 0, false
+}
+
+func archrelocvariant(*ld.Target, *loader.Loader, loader.Reloc, sym.RelocVariant, loader.Sym, int64) int64 {
+	log.Fatalf("unexpected relocation variant")
+	return -1
+}
+
+func elfsetupplt(ctxt *ld.Link, plt, got *loader.SymbolBuilder, dynamic loader.Sym) {
+	if plt.Size() == 0 {
+		// pushl got+4
+		plt.AddUint8(0xff)
+
+		plt.AddUint8(0x35)
+		plt.AddAddrPlus(ctxt.Arch, got.Sym(), 4)
+
+		// jmp *got+8
+		plt.AddUint8(0xff)
+
+		plt.AddUint8(0x25)
+		plt.AddAddrPlus(ctxt.Arch, got.Sym(), 8)
+
+		// zero pad
+		plt.AddUint32(ctxt.Arch, 0)
+
+		// assume got->size == 0 too
+		got.AddAddrPlus(ctxt.Arch, dynamic, 0)
+
+		got.AddUint32(ctxt.Arch, 0)
+		got.AddUint32(ctxt.Arch, 0)
+	}
+}
+
+func addpltsym(target *ld.Target, ldr *loader.Loader, syms *ld.ArchSyms, s loader.Sym) {
+	if ldr.SymPlt(s) >= 0 {
+		return
+	}
+
+	ld.Adddynsym(ldr, target, syms, s)
+
+	if target.IsElf() {
+		plt := ldr.MakeSymbolUpdater(syms.PLT)
+		got := ldr.MakeSymbolUpdater(syms.GOTPLT)
+		rel := ldr.MakeSymbolUpdater(syms.RelPLT)
+		if plt.Size() == 0 {
+			panic("plt is not set up")
+		}
+
+		// jmpq *got+size
+		plt.AddUint8(0xff)
+
+		plt.AddUint8(0x25)
+		plt.AddAddrPlus(target.Arch, got.Sym(), got.Size())
+
+		// add to got: pointer to current pos in plt
+		got.AddAddrPlus(target.Arch, plt.Sym(), plt.Size())
+
+		// pushl $x
+		plt.AddUint8(0x68)
+
+		plt.AddUint32(target.Arch, uint32(rel.Size()))
+
+		// jmp .plt
+		plt.AddUint8(0xe9)
+
+		plt.AddUint32(target.Arch, uint32(-(plt.Size() + 4)))
+
+		// rel
+		rel.AddAddrPlus(target.Arch, got.Sym(), got.Size()-4)
+
+		sDynid := ldr.SymDynid(s)
+		rel.AddUint32(target.Arch, elf.R_INFO32(uint32(sDynid), uint32(elf.R_386_JMP_SLOT)))
+
+		ldr.SetPlt(s, int32(plt.Size()-16))
+	} else {
+		ldr.Errorf(s, "addpltsym: unsupported binary format")
+	}
+}
diff --git a/src/cmd/link/internal/x86/l.go b/src/cmd/link/internal/x86/l.go
new file mode 100644
index 0000000..5875d45
--- /dev/null
+++ b/src/cmd/link/internal/x86/l.go
@@ -0,0 +1,43 @@
+// Inferno utils/8l/l.h
+// https://bitbucket.org/inferno-os/inferno-os/src/master/utils/8l/l.h
+//
+//	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 x86
+
+const (
+	maxAlign  = 32 // max data alignment
+	minAlign  = 1  // min data alignment
+	funcAlign = 16
+)
+
+/* Used by ../internal/ld/dwarf.go */
+const (
+	dwarfRegSP = 4
+	dwarfRegLR = 8
+)
diff --git a/src/cmd/link/internal/x86/obj.go b/src/cmd/link/internal/x86/obj.go
new file mode 100644
index 0000000..a19437d
--- /dev/null
+++ b/src/cmd/link/internal/x86/obj.go
@@ -0,0 +1,116 @@
+// Inferno utils/8l/obj.c
+// https://bitbucket.org/inferno-os/inferno-os/src/master/utils/8l/obj.c
+//
+//	Copyright © 1994-1999 Lucent Technologies Inc.  All rights reserved.
+//	Portions Copyright © 1995-1997 C H Forsyth (forsyth@terzarima.net)
+//	Portions Copyright © 1997-1999 Vita Nuova Limited
+//	Portions Copyright © 2000-2007 Vita Nuova Holdings Limited (www.vitanuova.com)
+//	Portions Copyright © 2004,2006 Bruce Ellis
+//	Portions Copyright © 2005-2007 C H Forsyth (forsyth@terzarima.net)
+//	Revisions Copyright © 2000-2007 Lucent Technologies Inc. and others
+//	Portions Copyright © 2009 The Go Authors. All rights reserved.
+//
+// Permission is hereby granted, free of charge, to any person obtaining a copy
+// of this software and associated documentation files (the "Software"), to deal
+// in the Software without restriction, including without limitation the rights
+// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+// copies of the Software, and to permit persons to whom the Software is
+// furnished to do so, subject to the following conditions:
+//
+// The above copyright notice and this permission notice shall be included in
+// all copies or substantial portions of the Software.
+//
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL THE
+// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+// THE SOFTWARE.
+
+package x86
+
+import (
+	"cmd/internal/objabi"
+	"cmd/internal/sys"
+	"cmd/link/internal/ld"
+)
+
+func Init() (*sys.Arch, ld.Arch) {
+	arch := sys.Arch386
+
+	theArch := ld.Arch{
+		Funcalign:  funcAlign,
+		Maxalign:   maxAlign,
+		Minalign:   minAlign,
+		Dwarfregsp: dwarfRegSP,
+		Dwarfreglr: dwarfRegLR,
+		// 0xCC is INT $3 - breakpoint instruction
+		CodePad: []byte{0xCC},
+
+		Plan9Magic: uint32(4*11*11 + 7),
+
+		Adddynrel:        adddynrel,
+		Archinit:         archinit,
+		Archreloc:        archreloc,
+		Archrelocvariant: archrelocvariant,
+		Elfreloc1:        elfreloc1,
+		ElfrelocSize:     8,
+		Elfsetupplt:      elfsetupplt,
+		Gentext:          gentext,
+		Machoreloc1:      machoreloc1,
+		PEreloc1:         pereloc1,
+
+		Linuxdynld:   "/lib/ld-linux.so.2",
+		Freebsddynld: "/usr/libexec/ld-elf.so.1",
+		Openbsddynld: "/usr/libexec/ld.so",
+		Netbsddynld:  "/usr/libexec/ld.elf_so",
+		Solarisdynld: "/lib/ld.so.1",
+	}
+
+	return arch, theArch
+}
+
+func archinit(ctxt *ld.Link) {
+	switch ctxt.HeadType {
+	default:
+		ld.Exitf("unknown -H option: %v", ctxt.HeadType)
+
+	case objabi.Hplan9: /* plan 9 */
+		ld.HEADR = 32
+
+		if *ld.FlagTextAddr == -1 {
+			*ld.FlagTextAddr = 4096 + int64(ld.HEADR)
+		}
+		if *ld.FlagRound == -1 {
+			*ld.FlagRound = 4096
+		}
+
+	case objabi.Hdarwin: /* apple MACH */
+		ld.HEADR = ld.INITIAL_MACHO_HEADR
+		if *ld.FlagTextAddr == -1 {
+			*ld.FlagTextAddr = 4096 + int64(ld.HEADR)
+		}
+		if *ld.FlagRound == -1 {
+			*ld.FlagRound = 4096
+		}
+
+	case objabi.Hlinux, /* elf32 executable */
+		objabi.Hfreebsd,
+		objabi.Hnetbsd,
+		objabi.Hopenbsd:
+		ld.Elfinit(ctxt)
+
+		ld.HEADR = ld.ELFRESERVE
+		if *ld.FlagTextAddr == -1 {
+			*ld.FlagTextAddr = 0x08048000 + int64(ld.HEADR)
+		}
+		if *ld.FlagRound == -1 {
+			*ld.FlagRound = 4096
+		}
+
+	case objabi.Hwindows: /* PE executable */
+		// ld.HEADR, ld.FlagTextAddr, ld.FlagRound are set in ld.Peinit
+		return
+	}
+}