cmd/ld, cmd/6l: part 2 of solaris/amd64 linker changes.

Second part of the solaris/amd64 linker changes: relocation and symbol table.

LGTM=iant
R=golang-codereviews, iant
CC=golang-codereviews
https://golang.org/cl/61330043

src/cmd/6l/asm.c

@@ -207,6 +207,15 @@ adddynrel(LSym *s, Reloc *r)
 		return;
 	
 	case D_ADDR:
+		if(s->type == STEXT && iself) {
+			// The code is asking for the address of an external
+			// function.  We provide it with the address of the
+			// correspondent GOT symbol.
+			addgotsym(targ);
+			r->sym = linklookup(ctxt, ".got", 0);
+			r->add += targ->got;
+			return;
+		}
 		if(s->type != SDATA)
 			break;
 		if(iself) {
@@ -273,9 +282,12 @@ elfreloc1(Reloc *r, vlong sectoff)
 		break;
 
 	case D_PCREL:
-		if(r->siz == 4)
-			VPUT(R_X86_64_PC32 | (uint64)elfsym<<32);
-		else
+		if(r->siz == 4) {
+			if(r->xsym->type == SDYNIMPORT)
+				VPUT(R_X86_64_GOTPCREL | (uint64)elfsym<<32);
+			else
+				VPUT(R_X86_64_PC32 | (uint64)elfsym<<32);
+		} else
 			return -1;
 		break;
 	

src/cmd/ld/data.c

@@ -154,9 +154,9 @@ relocsym(LSym *s)
 		if(r->type >= 256)
 			continue;
 
-		if(r->sym != S && r->sym->type == SDYNIMPORT)
+		// Solaris needs the ability to reference dynimport symbols.
+		if(HEADTYPE != Hsolaris && r->sym != S && r->sym->type == SDYNIMPORT)
 			diag("unhandled relocation for %s (type %d rtype %d)", r->sym->name, r->sym->type, r->type);
-
 		if(r->sym != S && r->sym->type != STLSBSS && !r->sym->reachable)
 			diag("unreachable sym in relocation: %s %s", s->name, r->sym->name);
 
@@ -194,7 +194,7 @@ relocsym(LSym *s)
 					r->xadd += symaddr(rs) - symaddr(rs->outer);
 					rs = rs->outer;
 				}
-				if(rs->type != SHOSTOBJ && rs->sect == nil)
+				if(rs->type != SHOSTOBJ && rs->type != SDYNIMPORT && rs->sect == nil)
 					diag("missing section for %s", rs->name);
 				r->xsym = rs;
 
@@ -225,7 +225,7 @@ relocsym(LSym *s)
 					rs = rs->outer;
 				}
 				r->xadd -= r->siz; // relative to address after the relocated chunk
-				if(rs->type != SHOSTOBJ && rs->sect == nil)
+				if(rs->type != SHOSTOBJ && rs->type != SDYNIMPORT && rs->sect == nil)
 					diag("missing section for %s", rs->name);
 				r->xsym = rs;
 

src/cmd/ld/symtab.c

@@ -171,6 +171,7 @@ void
 asmelfsym(void)
 {
 	LSym *s;
+	char *name;
 
 	// the first symbol entry is reserved
 	putelfsyment(0, 0, 0, (STB_LOCAL<<4)|STT_NOTYPE, 0, 0);
@@ -196,9 +197,13 @@ asmelfsym(void)
 	genasmsym(putelfsym);
 	
 	for(s=ctxt->allsym; s!=S; s=s->allsym) {
-		if(s->type != SHOSTOBJ)
+		if(s->type != SHOSTOBJ && s->type != SDYNIMPORT)
 			continue;
-		putelfsyment(putelfstr(s->name), 0, 0, (STB_GLOBAL<<4)|STT_NOTYPE, 0, 0);
+		if(s->type == SDYNIMPORT)
+			name = s->extname;
+		else
+			name = s->name;
+		putelfsyment(putelfstr(name), 0, 0, (STB_GLOBAL<<4)|STT_NOTYPE, 0, 0);
 		s->elfsym = numelfsym++;
 	}
 }