cmd/link: make DynlinkingGo a method

This will allow it to depend on whether plugin.Open is a symbol to be
linked in.

Change-Id: Ie9aa4216f2510fe8b10bc4665c8b19622b7122ea
Reviewed-on: https://go-review.googlesource.com/27819Reviewed-by: Ian Lance Taylor <iant@golang.org>
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>

src/cmd/link/internal/amd64/asm.go

@@ -55,7 +55,7 @@ func Addcall(ctxt *ld.Link, s *ld.Symbol, t *ld.Symbol) int64 {
 }
 
 func gentext(ctxt *ld.Link) {
-	if !ld.DynlinkingGo() {
+	if !ctxt.DynlinkingGo() {
 		return
 	}
 	addmoduledata := ld.Linklookup(ctxt, "runtime.addmoduledata", 0)
@@ -342,7 +342,7 @@ func elfreloc1(ctxt *ld.Link, r *ld.Reloc, sectoff int64) int {
 	case obj.R_CALL:
 		if r.Siz == 4 {
 			if r.Xsym.Type == obj.SDYNIMPORT {
-				if ld.DynlinkingGo() {
+				if ctxt.DynlinkingGo() {
 					ld.Thearch.Vput(ld.R_X86_64_PLT32 | uint64(elfsym)<<32)
 				} else {
 					ld.Thearch.Vput(ld.R_X86_64_GOTPCREL | uint64(elfsym)<<32)

src/cmd/link/internal/amd64/obj.go

@@ -89,7 +89,7 @@ func archinit(ctxt *ld.Link) {
 		ld.Linkmode = ld.LinkInternal
 	}
 
-	if ld.Buildmode == ld.BuildmodeCArchive || ld.Buildmode == ld.BuildmodeCShared || ld.DynlinkingGo() {
+	if ld.Buildmode == ld.BuildmodeCArchive || ld.Buildmode == ld.BuildmodeCShared || ctxt.DynlinkingGo() {
 		ld.Linkmode = ld.LinkExternal
 	}
 

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

@@ -59,7 +59,7 @@ import (
 //                      c: R_ARM_GOT_PREL       local.moduledata
 
 func gentext(ctxt *ld.Link) {
-	if !ld.DynlinkingGo() {
+	if !ctxt.DynlinkingGo() {
 		return
 	}
 	addmoduledata := ld.Linklookup(ctxt, "runtime.addmoduledata", 0)

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

@@ -85,7 +85,7 @@ func archinit(ctxt *ld.Link) {
 		ld.Linkmode = ld.LinkInternal
 	}
 
-	if ld.Buildmode == ld.BuildmodeCArchive || ld.Buildmode == ld.BuildmodeCShared || ld.DynlinkingGo() {
+	if ld.Buildmode == ld.BuildmodeCArchive || ld.Buildmode == ld.BuildmodeCShared || ctxt.DynlinkingGo() {
 		ld.Linkmode = ld.LinkExternal
 	}
 

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

@@ -39,7 +39,7 @@ import (
 )
 
 func gentext(ctxt *ld.Link) {
-	if !ld.DynlinkingGo() {
+	if !ctxt.DynlinkingGo() {
 		return
 	}
 	addmoduledata := ld.Linklookup(ctxt, "runtime.addmoduledata", 0)
@@ -249,7 +249,7 @@ func archreloc(ctxt *ld.Link, r *ld.Reloc, s *ld.Symbol, val *int64) int {
 			// (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&obj.SHIDDEN != 0) || r.Sym.Attr.Local()) && r.Sym.Type == obj.STEXT && ld.DynlinkingGo() {
+			if !(r.Sym.Version != 0 || (r.Sym.Type&obj.SHIDDEN != 0) || r.Sym.Attr.Local()) && r.Sym.Type == obj.STEXT && ctxt.DynlinkingGo() {
 				if o2&0xffc00000 != 0xf9400000 {
 					ctxt.Diag("R_ARM64_GOTPCREL against unexpected instruction %x", o2)
 				}

src/cmd/link/internal/arm64/obj.go

@@ -103,7 +103,7 @@ func archinit(ctxt *ld.Link) {
 		break
 	}
 
-	if ld.Buildmode == ld.BuildmodeCShared || ld.DynlinkingGo() {
+	if ld.Buildmode == ld.BuildmodeCShared || ctxt.DynlinkingGo() {
 		ld.Linkmode = ld.LinkExternal
 	}
 

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

@@ -360,7 +360,7 @@ func relocsym(ctxt *Link, s *Symbol) {
 
 		// We need to be able to reference dynimport symbols when linking against
 		// shared libraries, and Solaris needs it always
-		if HEADTYPE != obj.Hsolaris && r.Sym != nil && r.Sym.Type == obj.SDYNIMPORT && !DynlinkingGo() {
+		if HEADTYPE != obj.Hsolaris && r.Sym != nil && r.Sym.Type == obj.SDYNIMPORT && !ctxt.DynlinkingGo() {
 			if !(SysArch.Family == sys.PPC64 && Linkmode == LinkExternal && r.Sym.Name == ".TOC.") {
 				ctxt.Diag("unhandled relocation for %s (type %d rtype %d)", r.Sym.Name, r.Sym.Type, r.Type)
 			}

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

@@ -63,7 +63,7 @@ func deadcode(ctxt *Link) {
 	methSym := Linkrlookup(ctxt, "reflect.Value.Method", 0)
 	reflectSeen := false
 
-	if DynlinkingGo() {
+	if ctxt.DynlinkingGo() {
 		// Exported methods may satisfy interfaces we don't know
 		// about yet when dynamically linking.
 		reflectSeen = true

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

@@ -155,7 +155,7 @@ type Section struct {
 
 // DynlinkingGo returns whether we are producing Go code that can live
 // in separate shared libraries linked together at runtime.
-func DynlinkingGo() bool {
+func (ctxt *Link) DynlinkingGo() bool {
 	return Buildmode == BuildmodeShared || *FlagLinkshared
 }
 
@@ -307,7 +307,7 @@ func libinit(ctxt *Link) {
 		}
 	}
 
-	if !DynlinkingGo() {
+	if !ctxt.DynlinkingGo() {
 		Linklookup(ctxt, *flagEntrySymbol, 0).Type = obj.SXREF
 	}
 }
@@ -466,7 +466,7 @@ func (ctxt *Link) loadlib() {
 			if ctxt.Library[i].Shlib != "" {
 				ldshlibsyms(ctxt, ctxt.Library[i].Shlib)
 			} else {
-				if DynlinkingGo() {
+				if ctxt.DynlinkingGo() {
 					Exitf("cannot implicitly include runtime/cgo in a shared library")
 				}
 				objfile(ctxt, ctxt.Library[i])
@@ -998,7 +998,7 @@ func (l *Link) hostlink() {
 		argv = append(argv, "-shared")
 	}
 
-	if Iself && DynlinkingGo() {
+	if Iself && l.DynlinkingGo() {
 		// We force all symbol resolution to be done at program startup
 		// because lazy PLT resolution can use large amounts of stack at
 		// times we cannot allow it to do so.
@@ -1639,7 +1639,7 @@ func stkcheck(ctxt *Link, up *chain, depth int) int {
 		// should never be called directly.
 		// onlyctxt.Diagnose the direct caller.
 		// TODO(mwhudson): actually think about this.
-		if depth == 1 && s.Type != obj.SXREF && !DynlinkingGo() &&
+		if depth == 1 && s.Type != obj.SXREF && !ctxt.DynlinkingGo() &&
 			Buildmode != BuildmodeCArchive && Buildmode != BuildmodePIE && Buildmode != BuildmodeCShared {
 			ctxt.Diag("call to external function %s", s.Name)
 		}

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

@@ -585,7 +585,7 @@ func (r *objReader) readSymName() string {
 			}
 			r.rdBuf = adjName[:0] // in case 2*n wasn't enough
 
-			if DynlinkingGo() {
+			if r.ctxt.DynlinkingGo() {
 				// These types are included in the symbol
 				// table when dynamically linking. To keep
 				// binary size down, we replace the names

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

@@ -46,14 +46,6 @@ func putelfstr(s string) int {
 		putelfstr("")
 	}
 
-	// When dynamically linking, we create Symbols by reading the names from
-	// the symbol tables of the shared libraries and so the names need to
-	// match exactly. Tools like DTrace will have to wait for now.
-	if !DynlinkingGo() {
-		// Rewrite · to . for ASCII-only tools like DTrace (sigh)
-		s = strings.Replace(s, "·", ".", -1)
-	}
-
 	off := len(Elfstrdat)
 	Elfstrdat = append(Elfstrdat, s...)
 	Elfstrdat = append(Elfstrdat, 0)
@@ -144,7 +136,7 @@ func putelfsym(ctxt *Link, x *Symbol, s string, t int, addr int64, size int64, v
 	// To avoid filling the dynamic table with lots of unnecessary symbols,
 	// mark all Go symbols local (not global) in the final executable.
 	// But when we're dynamically linking, we need all those global symbols.
-	if !DynlinkingGo() && Linkmode == LinkExternal && !x.Attr.CgoExportStatic() && elfshnum != SHN_UNDEF {
+	if !ctxt.DynlinkingGo() && Linkmode == LinkExternal && !x.Attr.CgoExportStatic() && elfshnum != SHN_UNDEF {
 		bind = STB_LOCAL
 	}
 
@@ -155,14 +147,22 @@ func putelfsym(ctxt *Link, x *Symbol, s string, t int, addr int64, size int64, v
 	if x.Type&obj.SHIDDEN != 0 {
 		other = STV_HIDDEN
 	}
-	if (Buildmode == BuildmodeCArchive || Buildmode == BuildmodePIE || DynlinkingGo()) && SysArch.Family == sys.PPC64 && type_ == STT_FUNC && x.Name != "runtime.duffzero" && x.Name != "runtime.duffcopy" {
+	if (Buildmode == BuildmodeCArchive || Buildmode == BuildmodePIE || ctxt.DynlinkingGo()) && SysArch.Family == sys.PPC64 && type_ == STT_FUNC && x.Name != "runtime.duffzero" && x.Name != "runtime.duffcopy" {
 		// On ppc64 the top three bits of the st_other field indicate how
 		// many instructions separate the global and local entry points. In
 		// our case it is two instructions, indicated by the value 3.
 		other |= 3 << 5
 	}
 
-	if DynlinkingGo() && bind == STB_GLOBAL && elfbind == STB_LOCAL && x.Type == obj.STEXT {
+	// When dynamically linking, we create Symbols by reading the names from
+	// the symbol tables of the shared libraries and so the names need to
+	// match exactly. Tools like DTrace will have to wait for now.
+	if !ctxt.DynlinkingGo() {
+		// Rewrite · to . for ASCII-only tools like DTrace (sigh)
+		s = strings.Replace(s, "·", ".", -1)
+	}
+
+	if ctxt.DynlinkingGo() && bind == STB_GLOBAL && elfbind == STB_LOCAL && x.Type == obj.STEXT {
 		// When dynamically linking, we want references to functions defined
 		// in this module to always be to the function object, not to the
 		// PLT. We force this by writing an additional local symbol for every
@@ -376,7 +376,7 @@ func (ctxt *Link) symtab() {
 		s.Size = 0
 		s.Attr |= AttrReachable
 		symtyperel = s
-	} else if !DynlinkingGo() {
+	} else if !ctxt.DynlinkingGo() {
 		s = Linklookup(ctxt, "type.*", 0)
 
 		s.Type = obj.STYPE
@@ -401,7 +401,7 @@ func (ctxt *Link) symtab() {
 	)
 
 	var symgofuncrel *Symbol
-	if !DynlinkingGo() {
+	if !ctxt.DynlinkingGo() {
 		if UseRelro() {
 			symgofuncrel = groupSym("go.funcrel.*", obj.SGOFUNCRELRO)
 		} else {
@@ -435,7 +435,7 @@ func (ctxt *Link) symtab() {
 
 		switch {
 		case strings.HasPrefix(s.Name, "type."):
-			if !DynlinkingGo() {
+			if !ctxt.DynlinkingGo() {
 				s.Attr |= AttrHidden
 			}
 			if UseRelro() {
@@ -478,7 +478,7 @@ func (ctxt *Link) symtab() {
 			s.Outer = symgcbits
 
 		case strings.HasSuffix(s.Name, "·f"):
-			if !DynlinkingGo() {
+			if !ctxt.DynlinkingGo() {
 				s.Attr |= AttrHidden
 			}
 			if UseRelro() {

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

@@ -185,7 +185,7 @@ func genaddmoduledata(ctxt *ld.Link) {
 }
 
 func gentext(ctxt *ld.Link) {
-	if ld.DynlinkingGo() {
+	if ctxt.DynlinkingGo() {
 		genaddmoduledata(ctxt)
 	}
 

src/cmd/link/internal/s390x/asm.go

@@ -48,7 +48,7 @@ import (
 //
 // The job of appending the moduledata is delegated to runtime.addmoduledata.
 func gentext(ctxt *ld.Link) {
-	if !ld.DynlinkingGo() {
+	if !ctxt.DynlinkingGo() {
 		return
 	}
 	addmoduledata := ld.Linklookup(ctxt, "runtime.addmoduledata", 0)

src/cmd/link/internal/s390x/obj.go

@@ -86,7 +86,7 @@ func archinit(ctxt *ld.Link) {
 		ld.Linkmode = ld.LinkInternal
 	}
 
-	if ld.Buildmode == ld.BuildmodeCArchive || ld.Buildmode == ld.BuildmodeCShared || ld.DynlinkingGo() {
+	if ld.Buildmode == ld.BuildmodeCArchive || ld.Buildmode == ld.BuildmodeCShared || ctxt.DynlinkingGo() {
 		ld.Linkmode = ld.LinkExternal
 	}
 

src/cmd/link/internal/x86/asm.go

@@ -50,7 +50,7 @@ func addcall(ctxt *ld.Link, s *ld.Symbol, t *ld.Symbol) {
 }
 
 func gentext(ctxt *ld.Link) {
-	if ld.DynlinkingGo() {
+	if ctxt.DynlinkingGo() {
 		// We need get_pc_thunk.
 	} else {
 		switch ld.Buildmode {

src/cmd/link/internal/x86/obj.go

@@ -85,7 +85,7 @@ func archinit(ctxt *ld.Link) {
 		ld.Linkmode = ld.LinkInternal
 	}
 
-	if (ld.Buildmode == ld.BuildmodeCArchive && ld.Iself) || ld.Buildmode == ld.BuildmodeCShared || ld.Buildmode == ld.BuildmodePIE || ld.DynlinkingGo() {
+	if (ld.Buildmode == ld.BuildmodeCArchive && ld.Iself) || ld.Buildmode == ld.BuildmodeCShared || ld.Buildmode == ld.BuildmodePIE || ctxt.DynlinkingGo() {
 		ld.Linkmode = ld.LinkExternal
 		got := ld.Linklookup(ctxt, "_GLOBAL_OFFSET_TABLE_", 0)
 		got.Type = obj.SDYNIMPORT