[dev.link] all: merge branch 'master' into dev.linkdev.link

Clean merge.

Change-Id: Ia7b2808bc649790198d34c226a61d9e569084dc5

1 files changed, 37 insertions, 18 deletions

diff --git a/src/cmd/link/internal/ld/lib.go b/src/cmd/link/internal/ld/lib.go
index f5d41a0b4a..73e0b35bc0 100644
--- a/src/cmd/link/internal/ld/lib.go
+++ b/src/cmd/link/internal/ld/lib.go
@@ -247,12 +247,16 @@ type Arch struct {
 	Elfreloc1      func(*Link, *OutBuf, *loader.Loader, loader.Sym, loader.ExtReloc, int, int64) bool
 	ElfrelocSize   uint32 // size of an ELF relocation record, must match Elfreloc1.
 	Elfsetupplt    func(ctxt *Link, plt, gotplt *loader.SymbolBuilder, dynamic loader.Sym)
-	Gentext        func(*Link, *loader.Loader)
+	Gentext        func(*Link, *loader.Loader) // Generate text before addressing has been performed.
 	Machoreloc1    func(*sys.Arch, *OutBuf, *loader.Loader, loader.Sym, loader.ExtReloc, int64) bool
 	MachorelocSize uint32 // size of an Mach-O relocation record, must match Machoreloc1.
 	PEreloc1       func(*sys.Arch, *OutBuf, *loader.Loader, loader.Sym, loader.ExtReloc, int64) bool
 	Xcoffreloc1    func(*sys.Arch, *OutBuf, *loader.Loader, loader.Sym, loader.ExtReloc, int64) bool
 
+	// Generate additional symbols for the native symbol table just prior to
+	// code generation.
+	GenSymsLate func(*Link, *loader.Loader)
+
 	// TLSIEtoLE converts a TLS Initial Executable relocation to
 	// a TLS Local Executable relocation.
 	//
@@ -1254,7 +1258,9 @@ func (ctxt *Link) hostlink() {
 			// -headerpad is incompatible with -fembed-bitcode.
 			argv = append(argv, "-Wl,-headerpad,1144")
 		}
-		if ctxt.DynlinkingGo() && !ctxt.Arch.InFamily(sys.ARM, sys.ARM64) {
+		if ctxt.DynlinkingGo() && objabi.GOOS != "ios" {
+			// -flat_namespace is deprecated on iOS.
+			// It is useful for supporting plugins. We don't support plugins on iOS.
 			argv = append(argv, "-Wl,-flat_namespace")
 		}
 		if !combineDwarf {
@@ -1290,6 +1296,17 @@ func (ctxt *Link) hostlink() {
 		argv = append(argv, "-Wl,-bbigtoc")
 	}
 
+	// Enable ASLR on Windows.
+	addASLRargs := func(argv []string) []string {
+		// Enable ASLR.
+		argv = append(argv, "-Wl,--dynamicbase")
+		// enable high-entropy ASLR on 64-bit.
+		if ctxt.Arch.PtrSize >= 8 {
+			argv = append(argv, "-Wl,--high-entropy-va")
+		}
+		return argv
+	}
+
 	switch ctxt.BuildMode {
 	case BuildModeExe:
 		if ctxt.HeadType == objabi.Hdarwin {
@@ -1302,12 +1319,7 @@ func (ctxt *Link) hostlink() {
 		switch ctxt.HeadType {
 		case objabi.Hdarwin, objabi.Haix:
 		case objabi.Hwindows:
-			// Enable ASLR.
-			argv = append(argv, "-Wl,--dynamicbase")
-			// enable high-entropy ASLR on 64-bit.
-			if ctxt.Arch.PtrSize >= 8 {
-				argv = append(argv, "-Wl,--high-entropy-va")
-			}
+			argv = addASLRargs(argv)
 			// Work around binutils limitation that strips relocation table for dynamicbase.
 			// See https://sourceware.org/bugzilla/show_bug.cgi?id=19011
 			argv = append(argv, "-Wl,--export-all-symbols")
@@ -1321,9 +1333,6 @@ func (ctxt *Link) hostlink() {
 	case BuildModeCShared:
 		if ctxt.HeadType == objabi.Hdarwin {
 			argv = append(argv, "-dynamiclib")
-			if ctxt.Arch.Family != sys.AMD64 {
-				argv = append(argv, "-Wl,-read_only_relocs,suppress")
-			}
 		} else {
 			// ELF.
 			argv = append(argv, "-Wl,-Bsymbolic")
@@ -1331,7 +1340,11 @@ func (ctxt *Link) hostlink() {
 				argv = append(argv, "-Wl,-z,relro")
 			}
 			argv = append(argv, "-shared")
-			if ctxt.HeadType != objabi.Hwindows {
+			if ctxt.HeadType == objabi.Hwindows {
+				if *flagAslr {
+					argv = addASLRargs(argv)
+				}
+			} else {
 				// Pass -z nodelete to mark the shared library as
 				// non-closeable: a dlclose will do nothing.
 				argv = append(argv, "-Wl,-z,nodelete")
@@ -1601,12 +1614,12 @@ func (ctxt *Link) hostlink() {
 
 	if combineDwarf {
 		dsym := filepath.Join(*flagTmpdir, "go.dwarf")
-		if out, err := exec.Command("dsymutil", "-f", *flagOutfile, "-o", dsym).CombinedOutput(); err != nil {
+		if out, err := exec.Command("xcrun", "dsymutil", "-f", *flagOutfile, "-o", dsym).CombinedOutput(); err != nil {
 			Exitf("%s: running dsymutil failed: %v\n%s", os.Args[0], err, out)
 		}
 		// Remove STAB (symbolic debugging) symbols after we are done with them (by dsymutil).
 		// They contain temporary file paths and make the build not reproducible.
-		if out, err := exec.Command("strip", "-S", *flagOutfile).CombinedOutput(); err != nil {
+		if out, err := exec.Command("xcrun", "strip", "-S", *flagOutfile).CombinedOutput(); err != nil {
 			Exitf("%s: running strip failed: %v\n%s", os.Args[0], err, out)
 		}
 		// Skip combining if `dsymutil` didn't generate a file. See #11994.
@@ -1757,12 +1770,12 @@ func ldobj(ctxt *Link, f *bio.Reader, lib *sym.Library, length int64, pn string,
 	magic := uint32(c1)<<24 | uint32(c2)<<16 | uint32(c3)<<8 | uint32(c4)
 	if magic == 0x7f454c46 { // \x7F E L F
 		ldelf := func(ctxt *Link, f *bio.Reader, pkg string, length int64, pn string) {
-			textp, flags, err := loadelf.Load(ctxt.loader, ctxt.Arch, ctxt.IncVersion(), f, pkg, length, pn, ehdr.flags)
+			textp, flags, err := loadelf.Load(ctxt.loader, ctxt.Arch, ctxt.IncVersion(), f, pkg, length, pn, ehdr.Flags)
 			if err != nil {
 				Errorf(nil, "%v", err)
 				return
 			}
-			ehdr.flags = flags
+			ehdr.Flags = flags
 			ctxt.Textp = append(ctxt.Textp, textp...)
 		}
 		return ldhostobj(ldelf, ctxt.HeadType, f, pkg, length, pn, file)
@@ -2507,16 +2520,22 @@ func AddGotSym(target *Target, ldr *loader.Loader, syms *ArchSyms, s loader.Sym,
 		if target.Arch.PtrSize == 8 {
 			rela := ldr.MakeSymbolUpdater(syms.Rela)
 			rela.AddAddrPlus(target.Arch, got.Sym(), int64(ldr.SymGot(s)))
-			rela.AddUint64(target.Arch, ELF64_R_INFO(uint32(ldr.SymDynid(s)), elfRelocTyp))
+			rela.AddUint64(target.Arch, elf.R_INFO(uint32(ldr.SymDynid(s)), elfRelocTyp))
 			rela.AddUint64(target.Arch, 0)
 		} else {
 			rel := ldr.MakeSymbolUpdater(syms.Rel)
 			rel.AddAddrPlus(target.Arch, got.Sym(), int64(ldr.SymGot(s)))
-			rel.AddUint32(target.Arch, ELF32_R_INFO(uint32(ldr.SymDynid(s)), elfRelocTyp))
+			rel.AddUint32(target.Arch, elf.R_INFO32(uint32(ldr.SymDynid(s)), elfRelocTyp))
 		}
 	} else if target.IsDarwin() {
 		leg := ldr.MakeSymbolUpdater(syms.LinkEditGOT)
 		leg.AddUint32(target.Arch, uint32(ldr.SymDynid(s)))
+		if target.IsPIE() && target.IsInternal() {
+			// Mach-O relocations are a royal pain to lay out.
+			// They use a compact stateful bytecode representation.
+			// Here we record what are needed and encode them later.
+			MachoAddBind(int64(ldr.SymGot(s)), s)
+		}
 	} else {
 		ldr.Errorf(s, "addgotsym: unsupported binary format")
 	}