From ee9991adbd13a5e82b217cecbd6f2de8e1637c66 Mon Sep 17 00:00:00 2001
From: helixhorned <helixhorned@1a8010ca-5511-0410-912e-c29ae57300e0>
Date: Fri, 20 Jul 2012 21:57:34 +0000
Subject: [PATCH] Lunatic: more bitop profiling; make undeclared-var reads
 forbidden in modules

git-svn-id: https://svn.eduke32.com/eduke32@2839 1a8010ca-5511-0410-912e-c29ae57300e0
---
 polymer/eduke32/source/lunatic/bittest.lua | 50 +++++++++++++++++++++-
 polymer/eduke32/source/lunatic/defs.ilua   | 16 +++++--
 2 files changed, 62 insertions(+), 4 deletions(-)
 mode change 100644 => 100755 polymer/eduke32/source/lunatic/bittest.lua

diff --git a/polymer/eduke32/source/lunatic/bittest.lua b/polymer/eduke32/source/lunatic/bittest.lua
old mode 100644
new mode 100755
index 7efe1e7f6..64de2317d
--- a/polymer/eduke32/source/lunatic/bittest.lua
+++ b/polymer/eduke32/source/lunatic/bittest.lua
@@ -1,3 +1,4 @@
+#!/usr/bin/env luajit
 
 local string = require "string"
 
@@ -24,16 +25,62 @@ end
 local band, bxor = bit.band, bit.bxor
 local rshift, rol = bit.rshift, bit.rol
 
-local m = 1000000
+local m = string.dump and arg[1] or 1e7
 
 function sieve()
     local count = 0
     local p = {}
 
+    if (string.dump) then
+        -- stand-alone using unchecked int32_t array instead of table:
+        -- on x86_64 approx. 100 vs. 160 ms for m = 1e7
+        -- (enabling bound checking makes it be around 170 ms)
+        local ffi = require "ffi"
+        local pp = ffi.new("int32_t [?]", (m+31)/32 + 1)
+
+        p = pp
+--[[
+        local mt = {
+            __index = function(tab,idx)
+                if (idx >= 0 and idx <= (m+31)/32) then
+                    return pp[idx]
+                end
+            end,
+
+            __newindex = function(tab,idx,val)
+                if (idx >= 0 and idx <= (m+31)/32) then
+                    pp[idx] = val
+                end
+            end,
+        }
+
+        p = setmetatable({}, mt)
+--]]
+    end
+
     for i=0,(m+31)/32 do p[i] = -1 end
 
     local t = getticks()
 
+    -- See http://luajit.org/ext_ffi_tutorial.html,
+    -- "To Cache or Not to Cache"
+    -- bit. - qualified version: with m=1e7 ond x86_64:
+    -- 165 ms embedded, 100 ms stand-alone
+---[[
+    for i=2,m do
+        if bit.band(bit.rshift(p[bit.rshift(i, 5)], i), 1) ~= 0 then
+            count = count + 1
+            for j=i+i,m,i do
+                local jx = bit.rshift(j, 5)
+                p[jx] = bit.band(p[jx], bit.rol(-2, j))
+            end
+        end
+    end
+--]]
+
+    -- local var version: with m=1e7 on x86_64:
+    -- 205 ms embedded, 90 ms stand-alone
+--[[
     for i=2,m do
         if band(rshift(p[rshift(i, 5)], i), 1) ~= 0 then
             count = count + 1
@@ -43,6 +90,7 @@ function sieve()
             end
         end
     end
+--]]
 
     print(string.format("Found %d primes up to %d (%.02f ms)", count, m,
                         getticks()-t))
diff --git a/polymer/eduke32/source/lunatic/defs.ilua b/polymer/eduke32/source/lunatic/defs.ilua
index bf423c8c5..b1beb6a08 100644
--- a/polymer/eduke32/source/lunatic/defs.ilua
+++ b/polymer/eduke32/source/lunatic/defs.ilua
@@ -626,11 +626,17 @@ local G_ = {}  -- our soon-to-be global environment
 -- this table, since user code could later do pairs=nil.
 local oG = _G
 
+local module_mt = {
+    __index = function (_, n)
+        error("attempt to read undeclared variable '"..n.."'", 2)
+    end,
+}
+
 -- replacement for "module"
 local function our_module(modname)
     check_valid_modname(modname)
 
-    local M = {}
+    local M = oG.setmetatable({}, module_mt)
     package_loaded[modname] = M
     -- change the environment of the function which called us:
     oG.setfenv(2, M)
@@ -911,11 +917,15 @@ local gamevarNames = {}
 -- based on 14.2 of PiL
 function gamevar(name, initval)  -- aka 'declare'
     if (type(name) ~= "string") then
-        error("First argument to 'gamevar' must be a string", 2);
+        error("First argument to 'gamevar' must be a string", 2)
     end
 
     if (not string.match(name, "^[%a_][%w_]*$")) then
-        error("First argument to 'gamevar' must be a valid identifier", 2);
+        error("First argument to 'gamevar' must be a valid identifier", 2)
+    end
+
+    if (string.match(name, "^_")) then
+        error("Identifier names starting with an underscore are reserved", 2)
     end
 
     if (gamevarNames[name]) then