4987 - support `browse_trace` tool in SubX

I've extracted it into a separate binary, independent of my Mu prototype.

I also cleaned up my tracing layer to be a little nicer. Major improvements:

- Realized that incremental tracing really ought to be the default.
  And to minimize printing traces to screen.

- Finally figured out how to combine layers and call stack frames in a
  single dimension of depth. The answer: optimize for the experience of
  `browse_trace`. Instructions occupy a range of depths based on their call
  stack frame, and minor details of an instruction lie one level deeper
  in each case.

Other than that, I spent some time adjusting levels everywhere to make
`browse_trace` useful.

1 files changed, 3 insertions, 3 deletions

diff --git a/036abandon.cc b/036abandon.cc
index c2b9125e..4dcf572f 100644
--- a/036abandon.cc
+++ b/036abandon.cc
@@ -67,7 +67,7 @@ void abandon(int address, int payload_size) {
   for (int curr = address+1;  curr < address+payload_size;  ++curr)
     put(Memory, curr, 0);
   // append existing free list to address
-  trace("abandon") << "saving " << address << " in free-list of size " << payload_size << end();
+  trace(Callstack_depth+1, "abandon") << "saving " << address << " in free-list of size " << payload_size << end();
   put(Memory, address+/*skip invalid alloc-id*/1, get_or_insert(Current_routine->free_list, payload_size));
   put(Current_routine->free_list, payload_size, address);
 }
@@ -80,9 +80,9 @@ int payload_size(reagent/*copy*/ x) {
 
 :(after "Allocate Special-cases")
 if (get_or_insert(Current_routine->free_list, size)) {
-  trace("abandon") << "picking up space from free-list of size " << size << end();
+  trace(Callstack_depth+1, "abandon") << "picking up space from free-list of size " << size << end();
   int result = get_or_insert(Current_routine->free_list, size);
-  trace("mem") << "new alloc from free list: " << result << end();
+  trace(Callstack_depth+1, "mem") << "new alloc from free list: " << result << end();
   put(Current_routine->free_list, size, get_or_insert(Memory, result+/*skip alloc id*/1));
   // clear 'deleted' tag
   put(Memory, result, 0);