include, linlink, cmd/6l, cmd/ld: part 1 of solaris/amd64 linker changes.

rsc suggested that we split the whole linker changes into three parts.
This is the first one, mostly dealing with adding Hsolaris.

LGTM=iant
R=golang-codereviews, iant, dave
CC=golang-codereviews
https://golang.org/cl/54210050

include/link.h

@@ -451,6 +451,7 @@ enum {
 	Hnetbsd,
 	Hopenbsd,
 	Hplan9,
+	Hsolaris,
 	Hwindows,
 };
 

src/cmd/5l/asm.c

@@ -41,6 +41,7 @@ char freebsddynld[] = "/usr/libexec/ld-elf.so.1";
 char openbsddynld[] = "XXX";
 char netbsddynld[] = "/libexec/ld.elf_so";
 char dragonflydynld[] = "XXX";
+char solarisdynld[] = "XXX";
 
 static int
 needlib(char *name)

src/cmd/6l/asm.c

@@ -44,6 +44,7 @@ char freebsddynld[] = "/libexec/ld-elf.so.1";
 char openbsddynld[] = "/usr/libexec/ld.so";
 char netbsddynld[] = "/libexec/ld.elf_so";
 char dragonflydynld[] = "/usr/libexec/ld-elf.so.2";
+char solarisdynld[] = "/lib/amd64/ld.so.1";
 
 char	zeroes[32];
 
@@ -645,6 +646,7 @@ asmb(void)
 	case Hnetbsd:
 	case Hopenbsd:
 	case Hdragonfly:
+	case Hsolaris:
 		debug['8'] = 1;	/* 64-bit addresses */
 		break;
 	case Hwindows:
@@ -674,6 +676,7 @@ asmb(void)
 		case Hnetbsd:
 		case Hopenbsd:
 		case Hdragonfly:
+		case Hsolaris:
 			symo = rnd(HEADR+segtext.len, INITRND)+rnd(segrodata.len, INITRND)+segdata.filelen;
 			symo = rnd(symo, INITRND);
 			break;
@@ -754,6 +757,7 @@ asmb(void)
 	case Hnetbsd:
 	case Hopenbsd:
 	case Hdragonfly:
+	case Hsolaris:
 		asmbelf(symo);
 		break;
 	case Hwindows:

src/cmd/6l/obj.c

@@ -65,6 +65,7 @@ archinit(void)
 	case Hlinux:
 	case Hnetbsd:
 	case Hopenbsd:
+	case Hsolaris:
 		break;
 	}
 	ctxt->linkmode = linkmode;
@@ -106,6 +107,7 @@ archinit(void)
 	case Hnetbsd:		/* netbsd */
 	case Hopenbsd:		/* openbsd */
 	case Hdragonfly:	/* dragonfly */
+	case Hsolaris:		/* solaris */
 		elfinit();
 		HEADR = ELFRESERVE;
 		if(INITTEXT == -1)

src/cmd/8l/asm.c

@@ -42,6 +42,7 @@ char freebsddynld[] = "/usr/libexec/ld-elf.so.1";
 char openbsddynld[] = "/usr/libexec/ld.so";
 char netbsddynld[] = "/usr/libexec/ld.elf_so";
 char dragonflydynld[] = "/usr/libexec/ld-elf.so.2";
+char solarisdynld[] = "/lib/ld.so.1";
 
 static int
 needlib(char *name)

src/cmd/ld/doc.go

@@ -43,6 +43,8 @@ Options new in this version:
 		Write NetBSD ELF binaries (default when $GOOS is netbsd)
 	-H openbsd    (only in 6l/8l)
 		Write OpenBSD ELF binaries (default when $GOOS is openbsd)
+	-H solaris    (only in 6l)
+		Write Solaris ELF binaries (default when $GOOS is solaris)
 	-H windows    (only in 6l/8l)
 		Write Windows PE32+ Console binaries (default when $GOOS is windows)
 	-H windowsgui (only in 6l/8l)

src/cmd/ld/elf.c

@@ -677,6 +677,23 @@ elfdynhash(void)
 		elfwritedynent(s, DT_VERNEEDNUM, nfile);
 		elfwritedynentsym(s, DT_VERSYM, linklookup(ctxt, ".gnu.version", 0));
 	}
+
+	if(thechar == '6') {
+		sy = linklookup(ctxt, ".rela.plt", 0);
+		if(sy->size > 0) {
+			elfwritedynent(s, DT_PLTREL, DT_RELA);
+			elfwritedynentsymsize(s, DT_PLTRELSZ, sy);
+			elfwritedynentsym(s, DT_JMPREL, sy);
+		}
+	} else {
+		sy = linklookup(ctxt, ".rel.plt", 0);
+		if(sy->size > 0) {
+			elfwritedynent(s, DT_PLTREL, DT_REL);
+			elfwritedynentsymsize(s, DT_PLTRELSZ, sy);
+			elfwritedynentsym(s, DT_JMPREL, sy);
+		}
+	}
+
 	elfwritedynent(s, DT_NULL, 0);
 }
 
@@ -1058,16 +1075,10 @@ doelf(void)
 		
 		elfwritedynentsym(s, DT_PLTGOT, linklookup(ctxt, ".got.plt", 0));
 
-		if(thechar == '6') {
-			elfwritedynent(s, DT_PLTREL, DT_RELA);
-			elfwritedynentsymsize(s, DT_PLTRELSZ, linklookup(ctxt, ".rela.plt", 0));
-			elfwritedynentsym(s, DT_JMPREL, linklookup(ctxt, ".rela.plt", 0));
-		} else {
-			elfwritedynent(s, DT_PLTREL, DT_REL);
-			elfwritedynentsymsize(s, DT_PLTRELSZ, linklookup(ctxt, ".rel.plt", 0));
-			elfwritedynentsym(s, DT_JMPREL, linklookup(ctxt, ".rel.plt", 0));
-		}
-		
+		// Solaris dynamic linker can't handle an empty .rela.plt if
+		// DT_JMPREL is emitted so we have to defer generation of DT_PLTREL,
+		// DT_PLTRELSZ, and DT_JMPREL dynamic entries until after we know the
+		// size of .rel(a).plt section.
 		elfwritedynent(s, DT_DEBUG, 0);
 
 		// Do not write DT_NULL.  elfdynhash will finish it.
@@ -1192,6 +1203,9 @@ asmbelf(vlong symo)
 			case Hdragonfly:
 				interpreter = dragonflydynld;
 				break;
+			case Hsolaris:
+				interpreter = solarisdynld;
+				break;
 			}
 		}
 		resoff -= elfinterp(sh, startva, resoff, interpreter);

src/cmd/ld/elf.h

@@ -1010,6 +1010,7 @@ extern char freebsddynld[];
 extern char netbsddynld[];
 extern char openbsddynld[];
 extern char dragonflydynld[];
+extern char solarisdynld[];
 int	elfreloc1(Reloc*, vlong sectoff);
 void	putelfsectionsyms(void);
 

src/cmd/ld/lib.c

@@ -259,7 +259,9 @@ loadlib(void)
 	//
 	// Exception: on OS X, programs such as Shark only work with dynamic
 	// binaries, so leave it enabled on OS X (Mach-O) binaries.
-	if(!flag_shared && !havedynamic && HEADTYPE != Hdarwin)
+	// Also leave it enabled on Solaris which doesn't support
+	// statically linked binaries.
+	if(!flag_shared && !havedynamic && HEADTYPE != Hdarwin && HEADTYPE != Hsolaris)
 		debug['d'] = 1;
 	
 	importcycles();

src/liblink/obj6.c

@@ -137,7 +137,8 @@ progedit(Link *ctxt, Prog *p)
 	}
 	if(ctxt->headtype == Hlinux || ctxt->headtype == Hfreebsd
 	|| ctxt->headtype == Hopenbsd || ctxt->headtype == Hnetbsd
-	|| ctxt->headtype == Hplan9 || ctxt->headtype == Hdragonfly) {
+	|| ctxt->headtype == Hplan9 || ctxt->headtype == Hdragonfly
+	|| ctxt->headtype == Hsolaris) {
 		// ELF uses FS instead of GS.
 		if(p->from.type == D_INDIR+D_GS)
 			p->from.type = D_INDIR+D_FS;
@@ -577,7 +578,8 @@ load_g_cx(Link *ctxt, Prog *p)
 	p->as = AMOVQ;
 	if(ctxt->headtype == Hlinux || ctxt->headtype == Hfreebsd
 	|| ctxt->headtype == Hopenbsd || ctxt->headtype == Hnetbsd
-	|| ctxt->headtype == Hplan9 || ctxt->headtype == Hdragonfly)
+	|| ctxt->headtype == Hplan9 || ctxt->headtype == Hdragonfly
+	|| ctxt->headtype == Hsolaris)
 		// ELF uses FS
 		p->from.type = D_INDIR+D_FS;
 	else

src/liblink/sym.c

@@ -52,6 +52,7 @@ static struct {
 	"netbsd",	Hnetbsd,
 	"openbsd",	Hopenbsd,
 	"plan9",	Hplan9,
+	"solaris",	Hsolaris,
 	"windows",	Hwindows,
 	"windowsgui",	Hwindows,
 	0, 0
@@ -129,6 +130,7 @@ linknew(LinkArch *arch)
 	case Hnetbsd:
 	case Hopenbsd:
 	case Hdragonfly:
+	case Hsolaris:
 		/*
 		 * ELF uses TLS offset negative from FS.
 		 * Translate 0(FS) and 8(FS) into -16(FS) and -8(FS).