4421

Clean up the rat's nest that all my trace management globals had
gradually turned into.

  a) Get rid of 'Start_tracing'. Horryibly named, I don't know how I
  missed that until now.

  b) Never use START_TRACING_UNTIL_END_OF_SCOPE in main(). It's
  confusing to combine it with atexit(delete Trace_stream), because the
  atexit() never has to run. Instead we'll just manually initialize
  Trace_stream and let atexit() clean up.

  c) If we run tests we only want a trace for the test run itself. So
  delete the Trace_stream that was initialized at the top of main --
  once it's clear we had no load-time errors.

  d) Clean up horribly "Load Recipes" waypoints, combine them with the better
  name, "Mu Prelude".

Putting these together, we have the following manual tests:

  - CFLAGS=-g mu x.mu

    Should not create last_run.

  - CFLAGS=-g mu --trace x.mu

    Should create last_run.
    Should write it out exactly once.

  - CFLAGS=-g mu --trace x.mu  # when x.mu has an error

    Should create last_run.
    Should write it out exactly once.

  - CFLAGS=-g mu --trace test copy_literal  # C test

    Should create last_run.
    Should write it out exactly once.

  - CFLAGS=-g mu --trace test recipe_with_header  # Mu test

    Should create last_run.
    Should write it out exactly once.

I don't know how to automate these scenarios yet. We need a way to run
our build toolchain atop our stack.

1 files changed, 23 insertions, 0 deletions

diff --git a/003trace.cc b/003trace.cc
index 57604ee0..8fe3ebb0 100644
--- a/003trace.cc
+++ b/003trace.cc
@@ -85,6 +85,28 @@ Hide_errors = false;
 Dump_trace = false;
 Dump_label = "";
 
+//: Support for tracing an entire run.
+//: Traces can have a lot of overhead, so only turn them on when asked.
+:(before "End Commandline Options(*arg)")
+else if (is_equal(*arg, "--trace")) {
+  Save_trace = true;
+}
+:(before "End Commandline Parsing")
+if (Save_trace) {
+  cerr << "initializing trace\n";
+  Trace_stream = new trace_stream;
+}
+:(code)
+void cleanup_main() {
+  if (!Trace_stream) return;
+  if (Save_trace)
+    Trace_stream->save();
+  delete Trace_stream;
+  Trace_stream = NULL;
+}
+:(before "End One-time Setup")
+atexit(cleanup_main);
+
 :(before "End Types")
 // Pre-define some global constants that trace_stream needs to know about.
 // Since they're in the Types section, they'll be included in any cleaved
@@ -118,6 +140,7 @@ struct trace_stream {
   }
 
   void save() {
+    cerr << "saving trace to last_run\n";
     ofstream fout("last_run");
     fout << readable_contents("");
     fout.close();