compiler: don't export bodies for functions marked "go:noinline"

    
    The current Mark_inline_candidates helper looks only at budget when
    deciding to mark a function or method as inline (with the proviso that
    IR constructs not yet supported by the inliner are given artificially
    high cost). This patch changes the helper to also look at whether a
    function has the "go:noinline" pragma; if it does have the pragma
    there is no point putting it into the export data (it will just make
    the export data bigger).
    
    Reviewed-on: https://go-review.googlesource.com/c/gofrontend/+/186923

From-SVN: r273611

gcc/go/gofrontend/MERGE

-4df7c8d7af894ee93f50c3a50debdcf4e369a2c6
+e242929304e7a524ced56dc94605bbf6d83e6489
 
 The first line of this file holds the git revision number of the last
 merge done from the gofrontend repository.

gcc/go/gofrontend/gogo.cc

@@ -5109,6 +5109,8 @@ int
 Mark_inline_candidates::function(Named_object* no)
 {
   Function* func = no->func_value();
+  if ((func->pragmas() & GOPRAGMA_NOINLINE) != 0)
+    return TRAVERSE_CONTINUE;
   int budget = budget_heuristic;
   Inline_within_budget iwb(&budget);
   func->block()->traverse(&iwb);
@@ -5138,6 +5140,8 @@ Mark_inline_candidates::type(Type* t)
       Named_object* no = *p;
       go_assert(no->is_function());
       Function *func = no->func_value();
+      if ((func->pragmas() & GOPRAGMA_NOINLINE) != 0)
+        continue;
       int budget = budget_heuristic;
       Inline_within_budget iwb(&budget);
       func->block()->traverse(&iwb);