More fixes when calling an empty const Sub from :immediate #1024

Throw on NULL PMC arguments also for CallContext (sub args)
with "CallContext: Empty PMC argument"
Closes GH #1024, t/compilers/imcc/syn/const.t test 41

ChangeLog

@@ -9,6 +9,7 @@
         + Fix cmod_p_p_n* math dynops for NaN and Inf #1147
         + Fix floor, ceil and complex, integer math ops for NaN and Inf #422
         + Optimize printing of single numbers #828
+        + More fixes when calling an empty const Sub from :immediate #1024
     - Build
         + Extend auto::infnan probe to other --floatval #1146
         + Warn in Configure on experimental flags intval, floatval and gc #1148

src/call/args.c

@@ -403,6 +403,10 @@ Parrot_pcc_build_sig_object_from_op(PARROT_INTERP, ARGIN_NULLOK(PMC *signature),
                         ? Parrot_pcc_get_pmc_constant(interp, ctx, raw_index)
                         : CTX_REG_PMC(interp, ctx, raw_index);
 
+                if (!pmc_value)
+                    Parrot_ex_throw_from_c_noargs(interp,
+                        EXCEPTION_INVALID_OPERATION,
+                        "CallContext: Empty PMC argument");
                 if (arg_flags & PARROT_ARG_FLATTEN) {
                     dissect_aggregate_arg(interp, call_object, pmc_value);
                 }

src/call/context_accessors.c

@@ -1,5 +1,5 @@
 /*
-Copyright (C) 2009-2011, Parrot Foundation.
+Copyright (C) 2009-2014, Parrot Foundation.
 
 =head1 NAME
 

src/pmc/callcontext.pmc

@@ -1067,6 +1067,8 @@ return current Namespace
         Pcc_cell *cells;
         INTVAL    num_pos, allocated_positionals;
 
+        PARROT_ASSERT(value
+                || !"Push empty object into CallContext");
         PARROT_ASSERT(!PObj_on_free_list_TEST(value)
                 || !"Push dead object into CallContext");
 

t/compilers/imcc/syn/const.t

@@ -658,7 +658,7 @@ CODE
 /wrong .const value/
 OUT
 
-pir_exit_code_is( <<'CODE', 1, "missing const Sub should not SEGV [GH #1024]", todo => "dubious");
+pir_exit_code_is( <<'CODE', 1, "missing const Sub should not SEGV [GH #1024]");
 .sub baz :immediate :anon
   .const "Sub" foo = "foo"
   $P1 = foo."new"()