cmd/link: add AIX operating system

This commit adds AIX operating system to cmd/link package for ppc64
architecture.

Updates: #25893

Change-Id: I349e0a2658c31919b72117b62c4c9935c9af07c0
Reviewed-on: https://go-review.googlesource.com/c/138730
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>

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

@@ -314,6 +314,18 @@ func relocsym(ctxt *Link, s *sym.Symbol) {
 
 				break
 			}
+			// On AIX, if a relocated symbol is in .data, a second relocation
+			// must be done by the loader, as the section .data will be moved.
+			// The "default" symbol address is still needed by the loader so
+			// the current relocation can't be skipped.
+			// runtime.algarray is different because it will end up in .rodata section
+			if ctxt.HeadType == objabi.Haix && r.Sym.Sect.Seg == &Segdata && r.Sym.Name != "runtime.algarray" {
+				// It's not possible to make a loader relocation to a DWARF section.
+				// FIXME
+				if s.Sect.Seg != &Segdwarf {
+					xcoffaddloaderreloc(ctxt, s, r)
+				}
+			}
 
 			o = Symaddr(r.Sym) + r.Add
 
@@ -606,6 +618,7 @@ func dynrelocsym(ctxt *Link, s *sym.Symbol) {
 			thearch.Adddynrel(ctxt, s, r)
 			continue
 		}
+
 		if r.Sym != nil && r.Sym.Type == sym.SDYNIMPORT || r.Type >= 256 {
 			if r.Sym != nil && !r.Sym.Attr.Reachable() {
 				Errorf(s, "dynamic relocation to unreachable symbol %s", r.Sym.Name)
@@ -1329,6 +1342,14 @@ func (ctxt *Link) dodata() {
 		gc.AddSym(s)
 		datsize += s.Size
 	}
+	// On AIX, TOC entries must be the last of .data
+	for _, s := range data[sym.SXCOFFTOC] {
+		s.Sect = sect
+		s.Type = sym.SDATA
+		datsize = aligndatsize(datsize, s)
+		s.Value = int64(uint64(datsize) - sect.Vaddr)
+		datsize += s.Size
+	}
 	checkdatsize(ctxt, datsize, sym.SDATA)
 	sect.Length = uint64(datsize) - sect.Vaddr
 	gc.End(int64(sect.Length))
@@ -1688,6 +1709,10 @@ func (ctxt *Link) dodata() {
 	}
 	for _, sect := range Segdata.Sections {
 		sect.Extnum = int16(n)
+		if ctxt.HeadType == objabi.Haix && (sect.Name == ".noptrdata" || sect.Name == ".bss") {
+			// On AIX, "noptr" sections are merged with their "ptr" section
+			continue
+		}
 		n++
 	}
 	for _, sect := range Segdwarf.Sections {

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

@@ -163,6 +163,10 @@ func loadcgo(ctxt *Link, file string, pkg string, p string) {
 				}
 				havedynamic = 1
 			}
+			if ctxt.HeadType == objabi.Haix {
+				xcoffadddynimpsym(ctxt, s)
+			}
+
 			continue
 
 		case "cgo_import_static":
@@ -317,7 +321,8 @@ func fieldtrack(ctxt *Link) {
 }
 
 func (ctxt *Link) addexport() {
-	if ctxt.HeadType == objabi.Hdarwin {
+	// TODO(aix)
+	if ctxt.HeadType == objabi.Hdarwin || ctxt.HeadType == objabi.Haix {
 		return
 	}
 

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

@@ -39,6 +39,7 @@ import (
 	"cmd/link/internal/loadelf"
 	"cmd/link/internal/loadmacho"
 	"cmd/link/internal/loadpe"
+	"cmd/link/internal/loadxcoff"
 	"cmd/link/internal/objfile"
 	"cmd/link/internal/sym"
 	"crypto/sha1"
@@ -1517,6 +1518,18 @@ func ldobj(ctxt *Link, f *bio.Reader, lib *sym.Library, length int64, pn string,
 		return ldhostobj(ldpe, ctxt.HeadType, f, pkg, length, pn, file)
 	}
 
+	if c1 == 0x01 && (c2 == 0xD7 || c2 == 0xF7) {
+		ldxcoff := func(ctxt *Link, f *bio.Reader, pkg string, length int64, pn string) {
+			textp, err := loadxcoff.Load(ctxt.Arch, ctxt.Syms, f, pkg, length, pn)
+			if err != nil {
+				Errorf(nil, "%v", err)
+				return
+			}
+			ctxt.Textp = append(ctxt.Textp, textp...)
+		}
+		return ldhostobj(ldxcoff, ctxt.HeadType, f, pkg, length, pn, file)
+	}
+
 	/* check the header */
 	line, err := f.ReadString('\n')
 	if err != nil {
@@ -2243,7 +2256,7 @@ func Entryvalue(ctxt *Link) int64 {
 	if s.Type == 0 {
 		return *FlagTextAddr
 	}
-	if s.Type != sym.STEXT {
+	if ctxt.HeadType != objabi.Haix && s.Type != sym.STEXT {
 		Errorf(s, "entry not text")
 	}
 	return s.Value

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

@@ -224,6 +224,10 @@ func Main(arch *sys.Arch, theArch Arch) {
 		ctxt.dope()
 		ctxt.windynrelocsyms()
 	}
+	if ctxt.HeadType == objabi.Haix {
+		ctxt.doxcoff()
+	}
+
 	ctxt.addexport()
 	thearch.Gentext(ctxt) // trampolines, call stubs, etc.
 	ctxt.textbuildid()

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

@@ -66,7 +66,7 @@ func (ctxt *Link) computeTLSOffset() {
 	default:
 		log.Fatalf("unknown thread-local storage offset for %v", ctxt.HeadType)
 
-	case objabi.Hplan9, objabi.Hwindows, objabi.Hjs:
+	case objabi.Hplan9, objabi.Hwindows, objabi.Hjs, objabi.Haix:
 		break
 
 		/*

src/cmd/link/internal/ppc64/asm.go

@@ -692,6 +692,11 @@ func archreloc(ctxt *ld.Link, r *sym.Reloc, s *sym.Symbol, val int64) (int64, bo
 		// Runtime Handling" of "Power Architecture 64-Bit ELF V2 ABI
 		// Specification".
 		v := r.Sym.Value - 0x7000
+		if ctxt.HeadType == objabi.Haix {
+			// On AIX, the thread pointer points 0x7800 bytes after
+			// the TLS.
+			v -= 0x800
+		}
 		if int64(int16(v)) != v {
 			ld.Errorf(s, "TLS offset out of range %d", v)
 		}
@@ -941,6 +946,13 @@ func asmb(ctxt *ld.Link) {
 	ctxt.Out.SeekSet(int64(ld.Segdwarf.Fileoff))
 	ld.Dwarfblk(ctxt, int64(ld.Segdwarf.Vaddr), int64(ld.Segdwarf.Filelen))
 
+	loadersize := uint64(0)
+	if ctxt.HeadType == objabi.Haix && ctxt.BuildMode == ld.BuildModeExe {
+		loadero := uint64(ld.Rnd(int64(ld.Segdwarf.Fileoff+ld.Segdwarf.Filelen), int64(*ld.FlagRound)))
+		ctxt.Out.SeekSet(int64(loadero))
+		loadersize = ld.Loaderblk(ctxt, loadero)
+	}
+
 	/* output symbol table */
 	ld.Symsize = 0
 
@@ -960,6 +972,16 @@ func asmb(ctxt *ld.Link) {
 
 		case objabi.Hplan9:
 			symo = uint32(ld.Segdata.Fileoff + ld.Segdata.Filelen)
+
+		case objabi.Haix:
+			symo = uint32(ld.Segdwarf.Fileoff + ld.Segdwarf.Filelen)
+
+			// Add loader size if needed
+			if ctxt.BuildMode == ld.BuildModeExe {
+				symo = uint32(ld.Rnd(int64(symo), int64(*ld.FlagRound)))
+				symo += uint32(loadersize)
+			}
+			symo = uint32(ld.Rnd(int64(symo), int64(*ld.FlagRound)))
 		}
 
 		ctxt.Out.SeekSet(int64(symo))
@@ -988,6 +1010,10 @@ func asmb(ctxt *ld.Link) {
 				ctxt.Out.Write(sym.P)
 				ctxt.Out.Flush()
 			}
+
+		case objabi.Haix:
+			ld.Asmaixsym(ctxt)
+			ctxt.Out.Flush()
 		}
 	}
 
@@ -1013,6 +1039,9 @@ func asmb(ctxt *ld.Link) {
 		objabi.Hopenbsd,
 		objabi.Hnacl:
 		ld.Asmbelf(ctxt, int64(symo))
+
+	case objabi.Haix:
+		ld.Asmbxcoff(ctxt)
 	}
 
 	ctxt.Out.Flush()

src/cmd/link/internal/ppc64/obj.go

@@ -121,6 +121,10 @@ func archinit(ctxt *ld.Link) {
 		if *ld.FlagRound == -1 {
 			*ld.FlagRound = 0x10000
 		}
+
+	case objabi.Haix:
+		ld.Xcoffinit(ctxt)
+
 	}
 
 	if *ld.FlagDataAddr != 0 && *ld.FlagRound != 0 {