+StgClosure *stmReadTVar(Capability *cap,
+ StgTRecHeader *trec,
+ StgTVar *tvar) {
+ StgTRecHeader *entry_in;
+ StgClosure *result = NULL;
+ TRecEntry *entry = NULL;
+ TRACE("%p : stmReadTVar(%p)\n", trec, tvar);
+ ASSERT (trec != NO_TREC);
+ ASSERT (trec -> state == TREC_ACTIVE ||
+ trec -> state == TREC_CONDEMNED);
+
+ entry = get_entry_for(trec, tvar, &entry_in);
+
+ if (entry != NULL) {
+ if (entry_in == trec) {
+ // Entry found in our trec
+ result = entry -> new_value;
+ } else {
+ // Entry found in another trec
+ TRecEntry *new_entry = get_new_entry(cap, trec);
+ new_entry -> tvar = tvar;
+ new_entry -> expected_value = entry -> expected_value;
+ new_entry -> new_value = entry -> new_value;
+ result = new_entry -> new_value;
+ }
+ } else {
+ // No entry found
+ StgClosure *current_value = read_current_value(trec, tvar);
+ TRecEntry *new_entry = get_new_entry(cap, trec);
+ new_entry -> tvar = tvar;
+ new_entry -> expected_value = current_value;
+ new_entry -> new_value = current_value;
+ result = current_value;
+ }
+
+ TRACE("%p : stmReadTVar(%p)=%p\n", trec, tvar, result);