Add low-overhead profiler. Part 2: low-level Lua API.

src/jit/zone.lua

@@ -0,0 +1,41 @@
+----------------------------------------------------------------------------
+-- LuaJIT profiler zones.
+--
+-- Copyright (C) 2005-2013 Mike Pall. All rights reserved.
+-- Released under the MIT license. See Copyright Notice in luajit.h
+----------------------------------------------------------------------------
+--
+-- This module implements a simple hierarchical zone model.
+--
+-- Example usage:
+--
+--   local zone = require("jit.zone")
+--   zone("AI")
+--   ...
+--     zone("A*")
+--     ...
+--     print(zone:get()) --> "A*"
+--     ...
+--     zone()
+--   ...
+--   print(zone:get()) --> "AI"
+--   ...
+--   zone()
+--
+----------------------------------------------------------------------------
+
+local remove = table.remove
+
+return setmetatable({
+  flush = function(t)
+    for i=#t,1,-1 do t[i] = nil end
+  end,
+  get = function(t)
+    return t[#t]
+  end
+}, {
+  __call = function(t, zone)
+    if zone then t[#t+1] = zone else return assert(remove(t)) end
+  end
+})
+