ld: fix dwarf decoding of strings for struct's fieldnames

Moved Sym printing to Yconv.
Fixed warning in data.c

R=rsc
CC=golang-dev
https://golang.org/cl/4378052

src/cmd/ld/data.c

@@ -722,7 +722,7 @@ addsize(Sym *s, Sym *t)
 void
 dodata(void)
 {
-	int32 h, t, datsize;
+	int32 t, datsize;
 	Section *sect;
 	Sym *s, *last, **l;
 

src/cmd/ld/dwarf.c

@@ -6,7 +6,6 @@
 //   - eliminate DW_CLS_ if not used
 //   - package info in compilation units
 //   - assign global variables and types to their packages
-//   - (upstream) type info for C parts of runtime
 //   - gdb uses c syntax, meaning clumsy quoting is needed for go identifiers. eg
 //     ptype struct '[]uint8' and qualifiers need to be quoted away
 //   - lexical scoping is lost, so gdb gets confused as to which 'main.i' you mean.
@@ -943,14 +942,16 @@ enum {
 static char*
 decodetype_structfieldname(Sym *s, int i)
 {
+	Reloc *r;
+
 	// go.string."foo"  0x28 / 0x40
 	s = decode_reloc_sym(s, CommonSize + PtrSize + 2*4 + i*StructFieldSize);
 	if (s == nil)			// embedded structs have a nil name.
 		return nil;
-	s = decode_reloc_sym(s, 0);	// string."foo"
-	if (s == nil)			// shouldn't happen.
+	r = decode_reloc(s, 0);		// s has a pointer to the string data at offset 0
+	if (r == nil)			// shouldn't happen.
 		return nil;
-	return (char*)s->p;		// the c-string
+	return (char*) r->sym->p + r->add;	// the c-string
 }
 
 static Sym*
@@ -1021,22 +1022,8 @@ defgotype(Sym *gotype)
 	if (die != nil)
 		return die;
 
-	if (0 && debug['v'] > 2) {
-		print("new type: %s @0x%08x [%d]", gotype->name, gotype->value, gotype->size);
-		for (i = 0; i < gotype->size; i++) {
-			if (!(i%8)) print("\n\t%04x ", i);
-			print("%02x ", gotype->p[i]);
-		}
-		print("\n");
-		for (i = 0; i < gotype->nr; i++) {
-			print("\t0x%02x[%x] %d %s[%llx]\n",
-			      gotype->r[i].off,
-			      gotype->r[i].siz,
-			      gotype->r[i].type,
-			      gotype->r[i].sym->name,
-			      (vlong)gotype->r[i].add);
-		}
-	}
+	if (0 && debug['v'] > 2)
+		print("new type: %Y\n", gotype);
 
 	kind = decodetype_kind(gotype);
 	bytesize = decodetype_size(gotype);
@@ -2321,7 +2308,7 @@ dwarfemitdebugsections(void)
 {
 	vlong infoe;
 	DWDie* die;
-return;
+
 	// For diagnostic messages.
 	newattr(&dwtypes, DW_AT_name, DW_CLS_STRING, strlen("dwtypes"), "dwtypes");
 

src/cmd/ld/lib.c

@@ -61,6 +61,7 @@ void
 libinit(void)
 {
 	fmtinstall('i', iconv);
+	fmtinstall('Y', Yconv);
 	mywhatsys();	// get goroot, goarch, goos
 	if(strcmp(goarch, thestring) != 0)
 		print("goarch is not known: %s\n", goarch);
@@ -1307,3 +1308,38 @@ undef(void)
 		if(s->type == SXREF)
 			diag("%s(%d): not defined", s->name, s->version);
 }
+
+int
+Yconv(Fmt *fp)
+{
+	Sym *s;
+	Fmt fmt;
+	int i;
+	char *str;
+
+	s = va_arg(fp->args, Sym*);
+	if (s == S) {
+		fmtprint(fp, "<nil>");
+	} else {
+		fmtstrinit(&fmt);
+		fmtprint(&fmt, "%s @0x%08x [%d]", s->name, s->value, s->size);
+		for (i = 0; i < s->size; i++) {
+			if (!(i%8)) fmtprint(&fmt,  "\n\t0x%04x ", i);
+			fmtprint(&fmt, "%02x ", s->p[i]);
+		}
+		fmtprint(&fmt, "\n");
+		for (i = 0; i < s->nr; i++) {
+			fmtprint(&fmt, "\t0x%04x[%x] %d %s[%llx]\n",
+			      s->r[i].off,
+			      s->r[i].siz,
+			      s->r[i].type,
+			      s->r[i].sym->name,
+			      (vlong)s->r[i].add);
+		}
+		str = fmtstrflush(&fmt);
+		fmtstrcpy(fp, str);
+		free(str);
+	}
+
+	return 0;
+}

src/cmd/ld/lib.h

@@ -274,3 +274,6 @@ EXTERN	char*	headstring;
 extern	Header	headers[];
 
 int	headtype(char*);
+
+int	Yconv(Fmt*);
+#pragma	varargck	type	"Y"	Sym*