4179 - experiment: rip out memory reclamation

I have a plan for a way to avoid use-after-free errors without all the
overheads of maintaining refcounts. Has the nice side-effect of
requiring manual memory management. The Mu way is to leak memory by
default and build tools to help decide when and where to expend effort
plugging memory leaks. Arguably programs should be distributed with
summaries of their resource use characteristics.

Eliminating refcount maintenance reduces time to run tests by 30% for
`mu edit`:

              this commit                 parent
  mu test:         3.9s                        4.5s
  mu test edit:  2:38                        3:48

Open questions:
  - making reclamation easier; some sort of support for destructors
  - reclaiming local scopes (which are allocated on the heap)
    - should we support automatically reclaiming allocations inside them?

1 files changed, 0 insertions, 3 deletions

diff --git a/072recipe.cc b/072recipe.cc
index e76db812..fc53df09 100644
--- a/072recipe.cc
+++ b/072recipe.cc
@@ -97,9 +97,6 @@ case CALL: {
   Current_routine->calls.push_front(call(ingredients.at(0).at(0)));
   ingredients.erase(ingredients.begin());  // drop the callee
   finish_call_housekeeping(call_instruction, ingredients);
-  Num_refcount_updates[caller_frame.running_recipe][caller_frame.running_step_index]
-      += (Total_refcount_updates - initial_num_refcount_updates);
-  initial_num_refcount_updates = Total_refcount_updates;
   // not done with caller
   write_products = false;
   fall_through_to_next_instruction = false;