diff options
Diffstat (limited to '076continuation.cc')
| -rw-r--r-- | 076continuation.cc | 52 |
1 files changed, 46 insertions, 6 deletions
diff --git a/076continuation.cc b/076continuation.cc index 8cfda4a3..4b938c62 100644 --- a/076continuation.cc +++ b/076continuation.cc @@ -140,8 +140,14 @@ case CALL_WITH_CONTINUATION_MARK: { //: save the slice of current call stack until the 'call-with-continuation-mark' //: call, and return it as the result. //: todo: implement delimited continuations in Mu's memory +:(before "End Types") +struct delimited_continuation { + call_stack frames; + int nrefs; + delimited_continuation(call_stack::iterator begin, call_stack::iterator end) :frames(call_stack(begin, end)), nrefs(0) {} +}; :(before "End Globals") -map<long long int, call_stack> Delimited_continuation; +map<long long int, delimited_continuation> Delimited_continuation; long long int Next_delimited_continuation_id = 1; // 0 is null just like an address :(before "End Reset") Delimited_continuation.clear(); @@ -172,7 +178,7 @@ case RETURN_CONTINUATION_UNTIL_MARK: { break; } trace("run") << "creating continuation " << Next_delimited_continuation_id << end(); - put(Delimited_continuation, Next_delimited_continuation_id, call_stack(Current_routine->calls.begin(), base)); + put(Delimited_continuation, Next_delimited_continuation_id, delimited_continuation(Current_routine->calls.begin(), base)); while (Current_routine->calls.begin() != base) { if (Trace_stream) { --Trace_stream->callstack_depth; @@ -204,7 +210,7 @@ if (is_mu_continuation(current_instruction().ingredients.at(0))) { trace("run") << "calling continuation " << ingredients.at(0).at(0) << end(); if (!contains_key(Delimited_continuation, ingredients.at(0).at(0))) raise << maybe(current_recipe_name()) << "no such delimited continuation " << current_instruction().ingredients.at(0).original_string << '\n' << end(); - const call_stack& new_frames = get(Delimited_continuation, ingredients.at(0).at(0)); + const call_stack& new_frames = get(Delimited_continuation, ingredients.at(0).at(0)).frames; const call& caller = (SIZE(new_frames) > 1) ? *++new_frames.begin() : Current_routine->calls.front(); for (call_stack::const_reverse_iterator p = new_frames.rbegin(); p != new_frames.rend(); ++p) { Current_routine->calls.push_front(*p); @@ -296,19 +302,38 @@ def g [ # finally the alloc for main is abandoned +mem: automatically abandoning 1000 +:(before "End Increment Refcounts(canonized_x)") +if (is_mu_continuation(canonized_x)) { + int continuation_id = data.at(0); + if (continuation_id == 0) return; + if (!contains_key(Delimited_continuation, continuation_id)) { + raise << maybe(current_recipe_name()) << "missing delimited continuation: " << canonized_x.name << '\n'; + return; + } + delimited_continuation& curr = get(Delimited_continuation, continuation_id); + trace("run") << "incrementing refcount of continuation " << continuation_id << ": " << curr.nrefs << " -> " << 1+curr.nrefs << end(); + ++curr.nrefs; + return; +} + :(before "End Decrement Refcounts(canonized_x)") if (is_mu_continuation(canonized_x)) { int continuation_id = get_or_insert(Memory, canonized_x.value); - trace("run") << "reclaiming continuation " << continuation_id << end(); if (continuation_id == 0) return; - const call_stack& continuation_frames = get(Delimited_continuation, continuation_id); + delimited_continuation& curr = get(Delimited_continuation, continuation_id); + assert(curr.nrefs > 0); + --curr.nrefs; + trace("run") << "decrementing refcount of continuation " << continuation_id << ": " << 1+curr.nrefs << " -> " << curr.nrefs << end(); + if (curr.nrefs > 0) return; + trace("run") << "reclaiming continuation " << continuation_id << end(); // temporarily push the stack frames for the continuation to the call stack before reclaiming their spaces // (because reclaim_default_space() relies on the default-space being reclaimed being at the top of the stack) - for (call_stack::const_iterator p = continuation_frames.begin(); p != continuation_frames.end(); ++p) { + for (call_stack::const_iterator p = curr.frames.begin(); p != curr.frames.end(); ++p) { Current_routine->calls.push_front(*p); reclaim_default_space(); Current_routine->calls.pop_front(); } + Delimited_continuation.erase(continuation_id); return; } @@ -317,3 +342,18 @@ bool is_mu_continuation(reagent/*copy*/ x) { canonize_type(x); return x.type && x.type->atom && x.type->value == get(Type_ordinal, "continuation"); } + +:(scenario continuations_can_be_copied) +def main [ + local-scope + k:continuation <- call-with-continuation-mark f + k2:continuation <- copy k + # reclaiming k and k2 shouldn't delete f's local scope twice +] +def f [ + local-scope + load-ingredients + return-continuation-until-mark + return 0 +] +$error: 0 |