cmd/gc: do not generate dead value maps yet

We are not clearing dead values in the garbage collector so it
is not worth the RSS cost to materialize the data and write it
out to the binary.

R=golang-dev, iant, cshapiro
CC=golang-dev
https://golang.org/cl/38650043

diff --git a/src/cmd/gc/pgen.c b/src/cmd/gc/pgen.c
index c9ba893977e8a6d19e6e5e6f27913af1e7ee9348..aec785bcd0e549dde45476e0d2ac35905e664a1f 100644 (file)
--- a/src/cmd/gc/pgen.c
+++ b/src/cmd/gc/pgen.c
@@ -153,7 +153,15 @@ compile(Node *fn)
 
        gcargs = makefuncdatasym("gcargs·%d", FUNCDATA_ArgsPointerMaps);
        gclocals = makefuncdatasym("gclocals·%d", FUNCDATA_LocalsPointerMaps);
-       gcdead = makefuncdatasym("gcdead·%d", FUNCDATA_DeadPointerMaps);
+       // TODO(cshapiro): emit the dead value map when the garbage collector
+       // pre-verification pass is checked in.  It is otherwise harmless to
+       // emit this information if it is not used but it does cost RSS at
+       // compile time.  At present, the amount of additional RSS is
+       // substantial enough to affect our smallest build machines.
+       if(0)
+               gcdead = makefuncdatasym("gcdead·%d", FUNCDATA_DeadPointerMaps);
+       else
+               gcdead = nil;
 
        for(t=curfn->paramfld; t; t=t->down)
                gtrack(tracksym(t->type));