cmd/cc, cmd/gc: update compilers, assemblers for liblink changes

- add buffered stdout to all tools and provide to link ctxt.
- avoid extra \n before ! in .6 files written by assemblers
  (makes them match the C compilers).
- use linkwriteobj instead of linkouthist+linkwritefuncs.
- in assemblers and C compilers, record pc explicitly in Prog,
  for use by liblink.
- in C compilers, preserve jump target links.
- in Go compilers (gsubr.c) attach gotype directly to
  corresponding LSym* instead of rederiving from instruction stream.
- in Go compilers, emit just one definition for runtime.zerovalue
  from each compilation.

This CL consists entirely of small adjustments.
The heavy lifting is in CL 39680043.
Each depends on the other.

R=golang-dev, dave, iant
CC=golang-dev
https://codereview.appspot.com/37030045

1 files changed, 9 insertions, 4 deletions

diff --git a/src/cmd/gc/obj.c b/src/cmd/gc/obj.c
index c26b6619c..37d3a0326 100644
--- a/src/cmd/gc/obj.c
+++ b/src/cmd/gc/obj.c
@@ -16,6 +16,7 @@ void
 dumpobj(void)
 {
 	NodeList *externs, *tmp;
+	Sym *zero;
 
 	bout = Bopen(outfile, OWRITE);
 	if(bout == nil) {
@@ -30,8 +31,6 @@ dumpobj(void)
 	dumpexport();
 	Bprint(bout, "\n!\n");
 
-	linkouthist(ctxt, bout);
-
 	externs = nil;
 	if(externdcl != nil)
 		externs = externdcl->end;
@@ -46,8 +45,11 @@ dumpobj(void)
 	dumpglobls();
 	externdcl = tmp;
 
+	zero = pkglookup("zerovalue", runtimepkg);
+	ggloblsym(zero, zerosize, 1, 1);
+
 	dumpdata();
-	linkwritefuncs(ctxt, bout);
+	linkwriteobj(ctxt, bout);
 
 	Bterm(bout);
 }
@@ -74,12 +76,15 @@ dumpglobls(void)
 
 		ggloblnod(n);
 	}
-
+	
 	for(l=funcsyms; l; l=l->next) {
 		n = l->n;
 		dsymptr(n->sym, 0, n->sym->def->shortname->sym, 0);
 		ggloblsym(n->sym, widthptr, 1, 1);
 	}
+	
+	// Do not reprocess funcsyms on next dumpglobls call.
+	funcsyms = nil;
 }
 
 void