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, 83 insertions, 0 deletions

diff --git a/browse_trace/build b/browse_trace/build
new file mode 100755
index 00000000..6047cc2b
--- /dev/null
+++ b/browse_trace/build
@@ -0,0 +1,83 @@
+#!/bin/sh
+# For details on the basic form of this script, see https://notabug.org/akkartik/basic-build.
+
+set -e  # stop immediately on error
+
+# Some environment variables that can be passed in. For example, to turn off
+# optimization:
+#   $ CFLAGS=-g ./build2
+test "$CXX" || export CXX=c++
+test "$CC" || export CC=cc
+test "$CFLAGS" || export CFLAGS="-g -O2"
+export CFLAGS="$CFLAGS -Wall -Wextra -ftrapv -fno-strict-aliasing"
+
+# there's two mechanisms for fast builds here:
+# - if a command is quick to run, always run it but update the result only on any change
+# - otherwise run it only if the output is 'older_than' the inputs
+#
+# avoid combining both mechanisms for a single file
+# otherwise you'll see spurious messages about files being updated
+# risk: a file may unnecessarily update without changes, causing unnecessary work downstream
+
+# return 1 if $1 is older than _any_ of the remaining args
+older_than() {
+  local target=$1
+  shift
+  if [ ! -e $target ]
+  then
+#?     echo "$target doesn't exist"
+    echo "updating $target" >&2
+    return 0  # success
+  fi
+  local f
+  for f in $*
+  do
+    if [ $f -nt $target ]
+    then
+      echo "updating $target" >&2
+      return 0  # success
+    fi
+  done
+  return 1  # failure
+}
+
+# redirect to $1, unless it's already identical
+update() {
+  if [ ! -e $1 ]
+  then
+    cat > $1
+  else
+    cat > $1.tmp
+    diff -q $1 $1.tmp >/dev/null  &&  rm $1.tmp  ||  mv $1.tmp $1
+  fi
+}
+
+noisy_cd() {
+  cd $1
+  echo "-- `pwd`" >&2
+}
+
+older_than browse_trace_bin browse_trace.cc *_list ../termbox/*  &&  {
+  # missing some deps here
+  noisy_cd ../termbox
+    older_than ../termbox/libtermbox.a ../termbox/*.c  &&  {
+      older_than utf8.o utf8.c && {
+        $CC $CFLAGS -c utf8.c
+      }
+      older_than termbox.o termbox.c termbox.h input.inl output.inl bytebuffer.inl && {
+        $CC $CFLAGS -c termbox.c
+      }
+      older_than libtermbox.a *.o && {
+        ar rcs libtermbox.a *.o
+      }
+    }
+  noisy_cd ../browse_trace
+
+  grep -h "^[^[:space:]#].*) {$" browse_trace.cc  |grep -v ":.*("  |sed 's/ {.*/;/'  |update function_list
+  # auto-generate list of tests to run
+  grep -h "^\s*void test_" browse_trace.cc  |sed 's/^\s*void \(.*\)() {.*/\1,/'  |update test_list
+  grep -h "^\s*void test_" browse_trace.cc  |sed 's/^\s*void \(.*\)() {.*/"\1",/'  |update test_name_list
+  $CXX $CFLAGS browse_trace.cc ../termbox/libtermbox.a -o browse_trace_bin
+}
+
+exit 0