I spent more time tracking down the segfaults in Tcl (specifically the one
with an invalid string passed to string_equals()). The problem appears to be
in thawing bytecode, specifically in the ParrotInterpreter PMC and its
thawfinish().
The code there attempts to reconstruct specific bytecode elements which
represent .HLL directives -- what's the particular namespace, which op and
PMC libraries to load if any, and which dynpmc types map to builtins.
When IMCC encounters these directives, it calls functions in src/hll.c, which
fill in a PMC-based data structure which hangs off of interpreter->HLL_info.
This is a constant array full of constant PMCs. (They're constant so that
the garbage collector won't eat them.)
IMCC knows nothing about PBC though, so reconstructing a program from its PBC
doesn't go through IMCC. That's fine... except that the thawfinish() I
mentioned doesn't use the functions in src/hll.c. Worse, the thaw replaces
the top-level constant array PMC stuck in interpreter->HLL_info. (It's
constant, so it will hang out in memory. Yay for leaks.)
After tracing back from the segfault and annotating the source a little while,
I see some really weird garbage in the array, and only after thawing PBC
with .HLL directives.
Here's a patch which cleans up the issue somewhat, but doesn't fix up the
typemaps. I wonder if adding logic to iterate through any typemap PMC and
register types for the appropriate HLL id would fix everything else.
Certainly this breaks PBCs spectacularly, but I think it's closer to correct.
Is anyone sufficiently more familiar with the thawing code willing to look at
the code?
-- c
=== src/pmc/parrotinterpreter.pmc
==================================================================
--- src/pmc/parrotinterpreter.pmc (revision 5223)
+++ src/pmc/parrotinterpreter.pmc (local)
@@ -605,50 +605,48 @@
}
void thawfinish(visit_info *info) {
- INTVAL i, n, m;
- PMC *hll_info, *entry, *lib_pmc, *new_info, *ns_hash;
- STRING *lib_name, *hll_name;
+ PMC *hll_info = INTERP->HLL_info;
+ PMC *new_info = PMC_pmc_val(SELF);
+ INTVAL n = VTABLE_elements(INTERP, hll_info);
+ INTVAL m = VTABLE_elements(INTERP, new_info);
- hll_info = INTERP->HLL_info;
- n = VTABLE_elements(INTERP, hll_info);
- new_info = PMC_pmc_val(SELF);
+ INTVAL i;
+
PMC_pmc_val(SELF) = NULL;
- m = VTABLE_elements(INTERP, new_info);
/* merge new_info */
/* TODO compare old entries */
+
for (i = n; i < m; ++i) {
- entry = VTABLE_get_pmc_keyed_int(INTERP, new_info, i);
- lib_pmc = VTABLE_get_pmc_keyed_int(INTERP, entry, 1);
+ PMC *entry = VTABLE_get_pmc_keyed_int(INTERP, new_info, i);
+ PMC *lib_pmc = VTABLE_get_pmc_keyed_int(INTERP, entry, e_HLL_lib);
+ PMC *name_pmc = VTABLE_get_pmc_keyed_int(INTERP, entry, e_HLL_name);
+
+ STRING *lib_name = NULL;
+ STRING *hll_name = NULL;
+
if (!PMC_IS_NULL(lib_pmc)) {
lib_name = VTABLE_get_string(INTERP, lib_pmc);
- if (lib_name->strlen)
- Parrot_load_lib(INTERP, lib_name, NULL);
+ PObj_constant_SET(lib_name);
}
- entry = VTABLE_get_pmc_keyed_int(INTERP, entry, 0);
- if (!PMC_IS_NULL(entry)) {
+
+ if (!PMC_IS_NULL(name_pmc)) {
hll_name = VTABLE_get_string(INTERP, entry);
- /* create HLL namespace */
- hll_name = string_downcase(INTERP, hll_name);
+ PObj_constant_SET(hll_name);
+ }
- /* HLL type mappings aren't yet created, we can't create
- * a namespace in HLL's flavor yet - maybe promote the
- * ns_hash to another type later, if mappings provide one?
- * XXX - FIXME
- */
- ns_hash =
- Parrot_make_namespace_keyed_str(interp,
- interp->root_namespace,
- hll_name);
+ if (hll_name || lib_name) {
+ INTVAL id = Parrot_register_HLL(INTERP, hll_name, lib_name);
+ PMC *typemap =
+ VTABLE_get_pmc_keyed_int(INTERP, entry, e_HLL_typemap);
+ PMC *hll_info =
+ VTABLE_get_pmc_keyed_int(INTERP, INTERP->HLL_info, id);
- /* cache HLLs toplevel namespace */
- VTABLE_set_pmc_keyed_int(INTERP,
- INTERP->HLL_namespace, i, ns_hash);
+ fprintf( stderr, "Storing typemap for HLL %d\n", id );
+ dod_register_pmc(INTERP, typemap);
+ VTABLE_set_pmc_keyed_int(INTERP, hll_info, e_HLL_typemap,
+ typemap);
}
}
-
- /* TODO destruct old HLL_info are constants */
- if (m > n)
- INTERP->HLL_info = new_info;
}
METHOD void run_gc() {
