add profiling support

2 files changed, 184 insertions, 0 deletions

diff --git a/init.moon b/init.moon
index 638ef97..1c0f5ef 100644
--- a/init.moon
+++ b/init.moon
@@ -1,6 +1,7 @@
 import Input from require 'input'
 import State from require 'state'
 import Session, Script from require 'session'
+profile = require 'profile'
 
 export ^
 
@@ -13,8 +14,16 @@ for k, v in pairs require 'api'
   _G[k] = v
 
 love.draw = ->
+  p = INPUT\key_down 'p'
+  if p
+    profile.reset!
+    profile.start!
   SESSION\frame!
   INPUT\frame!
+  if p
+    profile.stop!
+    print love.timer.getFPS!
+    print profile.report 20
 love.keypressed    = INPUT\keypressed
 love.keyreleased   = INPUT\keyreleased
 love.mousemoved    = INPUT\mousemoved
diff --git a/profile.lua b/profile.lua
new file mode 100644
index 0000000..4609d3f
--- /dev/null
+++ b/profile.lua
@@ -0,0 +1,175 @@
+local clock = os.clock
+
+local profile = {}
+
+-- function labels
+local _labeled = {}
+-- function definitions
+local _defined = {}
+-- time of last call
+local _tcalled = {}
+-- total execution time
+local _telapsed = {}
+-- number of calls
+local _ncalls = {}
+-- list of internal profiler functions
+local _internal = {}
+
+function profile.hooker(event, line, info)
+  info = info or debug.getinfo(2, 'fnS')
+  local f = info.func
+  -- ignore the profiler itself
+  if _internal[f] or info.what ~= "Lua" then
+    return
+  end
+  -- get the function name if available
+  if info.name then
+    _labeled[f] = info.name
+  end
+  -- find the line definition
+  if not _defined[f] then
+    _defined[f] = info.short_src..":"..info.linedefined
+    _ncalls[f] = 0
+    _telapsed[f] = 0
+  end
+  if _tcalled[f] then
+    local dt = clock() - _tcalled[f]
+    _telapsed[f] = _telapsed[f] + dt
+    _tcalled[f] = nil
+  end
+  if event == "tail call" then
+    local prev = debug.getinfo(3, 'fnS')
+    profile.hooker("return", line, prev)
+    profile.hooker("call", line, info)
+  elseif event == 'call' then
+    _tcalled[f] = clock()
+  else
+    _ncalls[f] = _ncalls[f] + 1
+  end
+end
+
+--- Sets a clock function to be used by the profiler.
+-- @param f Clock function that returns a number
+function profile.setclock(f)
+  assert(type(f) == "function", "clock must be a function")
+  clock = f
+end
+
+--- Starts collecting data.
+function profile.start()
+  if rawget(_G, 'jit') then
+    jit.off()
+    jit.flush()
+  end
+  debug.sethook(profile.hooker, "cr")
+end
+
+--- Stops collecting data.
+function profile.stop()
+  debug.sethook()
+  for f in pairs(_tcalled) do
+    local dt = clock() - _tcalled[f]
+    _telapsed[f] = _telapsed[f] + dt
+    _tcalled[f] = nil
+  end
+  -- merge closures
+  local lookup = {}
+  for f, d in pairs(_defined) do
+    local id = (_labeled[f] or '?')..d
+    local f2 = lookup[id]
+    if f2 then
+      _ncalls[f2] = _ncalls[f2] + (_ncalls[f] or 0)
+      _telapsed[f2] = _telapsed[f2] + (_telapsed[f] or 0)
+      _defined[f], _labeled[f] = nil, nil
+      _ncalls[f], _telapsed[f] = nil, nil
+    else
+      lookup[id] = f
+    end
+  end
+  collectgarbage('collect')
+end
+
+--- Resets all collected data.
+function profile.reset()
+  for f in pairs(_ncalls) do
+    _ncalls[f] = 0
+  end
+  for f in pairs(_telapsed) do
+    _telapsed[f] = 0
+  end
+  for f in pairs(_tcalled) do
+    _tcalled[f] = nil
+  end
+  collectgarbage('collect')
+end
+
+function profile.comp(a, b)
+  local dt = _telapsed[b] - _telapsed[a]
+  if dt == 0 then
+    return _ncalls[b] < _ncalls[a]
+  end
+  return dt < 0
+end
+
+--- Iterates all functions that have been called since the profile was started.
+-- @param n Number of results (optional)
+function profile.query(limit)
+  local t = {}
+  for f, n in pairs(_ncalls) do
+    if n > 0 then
+      t[#t + 1] = f
+    end
+  end
+  table.sort(t, profile.comp)
+  if limit then
+    while #t > limit do
+      table.remove(t)
+    end
+  end
+  for i, f in ipairs(t) do
+    local dt = 0
+    if _tcalled[f] then
+      dt = clock() - _tcalled[f]
+    end
+    t[i] = { i, _labeled[f] or '?', _ncalls[f], _telapsed[f] + dt, _defined[f] }
+  end
+  return t
+end
+
+local cols = { 3, 29, 11, 24, 32 }
+function profile.report(n)
+  local out = {}
+  local report = profile.query(n)
+  for i, row in ipairs(report) do
+    for j = 1, 5 do
+      local s = row[j]
+      local l2 = cols[j]
+      s = tostring(s)
+      local l1 = s:len()
+      if l1 < l2 then
+        s = s..(' '):rep(l2-l1)
+      elseif l1 > l2 then
+        s = s:sub(l1 - l2 + 1, l1)
+      end
+      row[j] = s
+    end
+    out[i] = table.concat(row, ' | ')
+  end
+
+  local row = " +-----+-------------------------------+-------------+--------------------------+----------------------------------+ \n"
+  local col = " | #   | Function                      | Calls       | Time                     | Code                             | \n"
+  local sz = row..col..row
+  if #out > 0 then
+    sz = sz..' | '..table.concat(out, ' | \n | ')..' | \n'
+  end
+  return '\n'..sz..row
+end
+
+-- store all internal profiler functions
+for k, v in pairs(profile) do
+  if type(v) == "function" then
+    _internal[v] = true
+  end
+end
+
+return profile