contrib, build: bundle LuaSrcDiet and make it available in build targets

1 files changed, 564 insertions, 0 deletions

diff --git a/contrib/luasrcdiet/lua/optparser.lua b/contrib/luasrcdiet/lua/optparser.lua
new file mode 100644
index 0000000000..cfe6cc1013
--- /dev/null
+++ b/contrib/luasrcdiet/lua/optparser.lua
@@ -0,0 +1,564 @@
+--[[--------------------------------------------------------------------
+
+  optparser.lua: does parser-based optimizations
+  This file is part of LuaSrcDiet.
+
+  Copyright (c) 2008 Kein-Hong Man <khman@users.sf.net>
+  The COPYRIGHT file describes the conditions
+  under which this software may be distributed.
+
+  See the ChangeLog for more information.
+
+----------------------------------------------------------------------]]
+
+--[[--------------------------------------------------------------------
+-- NOTES:
+-- * For more parser-based optimization ideas, see the TODO items or
+--   look at technotes.txt.
+-- * The processing load is quite significant, but since this is an
+--   off-line text processor, I believe we can wait a few seconds.
+-- * TODO: might process "local a,a,a" wrongly... need tests!
+-- * TODO: remove position handling if overlapped locals (rem < 0)
+--   needs more study, to check behaviour
+-- * TODO: there are probably better ways to do allocation, e.g. by
+--   choosing better methods to sort and pick locals...
+-- * TODO: we don't need 53*63 two-letter identifiers; we can make
+--   do with significantly less depending on how many that are really
+--   needed and improve entropy; e.g. 13 needed -> choose 4*4 instead
+----------------------------------------------------------------------]]
+
+local base = _G
+local string = require "string"
+local table = require "table"
+module "optparser"
+
+----------------------------------------------------------------------
+-- Letter frequencies for reducing symbol entropy (fixed version)
+-- * Might help a wee bit when the output file is compressed
+-- * See Wikipedia: http://en.wikipedia.org/wiki/Letter_frequencies
+-- * We use letter frequencies according to a Linotype keyboard, plus
+--   the underscore, and both lower case and upper case letters.
+-- * The arrangement below (LC, underscore, %d, UC) is arbitrary.
+-- * This is certainly not optimal, but is quick-and-dirty and the
+--   process has no significant overhead
+----------------------------------------------------------------------
+
+local LETTERS = "etaoinshrdlucmfwypvbgkqjxz_ETAOINSHRDLUCMFWYPVBGKQJXZ"
+local ALPHANUM = "etaoinshrdlucmfwypvbgkqjxz_0123456789ETAOINSHRDLUCMFWYPVBGKQJXZ"
+
+-- names or identifiers that must be skipped
+-- * the first two lines are for keywords
+local SKIP_NAME = {}
+for v in string.gmatch([[
+and break do else elseif end false for function if in
+local nil not or repeat return then true until while
+self]], "%S+") do
+  SKIP_NAME[v] = true
+end
+
+------------------------------------------------------------------------
+-- variables and data structures
+------------------------------------------------------------------------
+
+local toklist, seminfolist,             -- token lists
+      globalinfo, localinfo,            -- variable information tables
+      globaluniq, localuniq,            -- unique name tables
+      var_new,                          -- index of new variable names
+      varlist                           -- list of output variables
+
+----------------------------------------------------------------------
+-- preprocess information table to get lists of unique names
+----------------------------------------------------------------------
+
+local function preprocess(infotable)
+  local uniqtable = {}
+  for i = 1, #infotable do              -- enumerate info table
+    local obj = infotable[i]
+    local name = obj.name
+    --------------------------------------------------------------------
+    if not uniqtable[name] then         -- not found, start an entry
+      uniqtable[name] = {
+        decl = 0, token = 0, size = 0,
+      }
+    end
+    --------------------------------------------------------------------
+    local uniq = uniqtable[name]        -- count declarations, tokens, size
+    uniq.decl = uniq.decl + 1
+    local xref = obj.xref
+    local xcount = #xref
+    uniq.token = uniq.token + xcount
+    uniq.size = uniq.size + xcount * #name
+    --------------------------------------------------------------------
+    if obj.decl then            -- if local table, create first,last pairs
+      obj.id = i
+      obj.xcount = xcount
+      if xcount > 1 then        -- if ==1, means local never accessed
+        obj.first = xref[2]
+        obj.last = xref[xcount]
+      end
+    --------------------------------------------------------------------
+    else                        -- if global table, add a back ref
+      uniq.id = i
+    end
+    --------------------------------------------------------------------
+  end--for
+  return uniqtable
+end
+
+----------------------------------------------------------------------
+-- calculate actual symbol frequencies, in order to reduce entropy
+-- * this may help further reduce the size of compressed sources
+-- * note that since parsing optimizations is put before lexing
+--   optimizations, the frequency table is not exact!
+-- * yes, this will miss --keep block comments too...
+----------------------------------------------------------------------
+
+local function recalc_for_entropy(option)
+  local byte = string.byte
+  local char = string.char
+  -- table of token classes to accept in calculating symbol frequency
+  local ACCEPT = {
+    TK_KEYWORD = true, TK_NAME = true, TK_NUMBER = true,
+    TK_STRING = true, TK_LSTRING = true,
+  }
+  if not option["opt-comments"] then
+    ACCEPT.TK_COMMENT = true
+    ACCEPT.TK_LCOMMENT = true
+  end
+  --------------------------------------------------------------------
+  -- create a new table and remove any original locals by filtering
+  --------------------------------------------------------------------
+  local filtered = {}
+  for i = 1, #toklist do
+    filtered[i] = seminfolist[i]
+  end
+  for i = 1, #localinfo do              -- enumerate local info table
+    local obj = localinfo[i]
+    local xref = obj.xref
+    for j = 1, obj.xcount do
+      local p = xref[j]
+      filtered[p] = ""                  -- remove locals
+    end
+  end
+  --------------------------------------------------------------------
+  local freq = {}                       -- reset symbol frequency table
+  for i = 0, 255 do freq[i] = 0 end
+  for i = 1, #toklist do                -- gather symbol frequency
+    local tok, info = toklist[i], filtered[i]
+    if ACCEPT[tok] then
+      for j = 1, #info do
+        local c = byte(info, j)
+        freq[c] = freq[c] + 1
+      end
+    end--if
+  end--for
+  --------------------------------------------------------------------
+  -- function to re-sort symbols according to actual frequencies
+  --------------------------------------------------------------------
+  local function resort(symbols)
+    local symlist = {}
+    for i = 1, #symbols do              -- prepare table to sort
+      local c = byte(symbols, i)
+      symlist[i] = { c = c, freq = freq[c], }
+    end
+    table.sort(symlist,                 -- sort selected symbols
+      function(v1, v2)
+        return v1.freq > v2.freq
+      end
+    )
+    local charlist = {}                 -- reconstitute the string
+    for i = 1, #symlist do
+      charlist[i] = char(symlist[i].c)
+    end
+    return table.concat(charlist)
+  end
+  --------------------------------------------------------------------
+  LETTERS = resort(LETTERS)             -- change letter arrangement
+  ALPHANUM = resort(ALPHANUM)
+end
+
+----------------------------------------------------------------------
+-- returns a string containing a new local variable name to use, and
+-- a flag indicating whether it collides with a global variable
+-- * trapping keywords and other names like 'self' is done elsewhere
+----------------------------------------------------------------------
+
+local function new_var_name()
+  local var
+  local cletters, calphanum = #LETTERS, #ALPHANUM
+  local v = var_new
+  if v < cletters then                  -- single char
+    v = v + 1
+    var = string.sub(LETTERS, v, v)
+  else                                  -- longer names
+    local range, sz = cletters, 1       -- calculate # chars fit
+    repeat
+      v = v - range
+      range = range * calphanum
+      sz = sz + 1
+    until range > v
+    local n = v % cletters              -- left side cycles faster
+    v = (v - n) / cletters              -- do first char first
+    n = n + 1
+    var = string.sub(LETTERS, n, n)
+    while sz > 1 do
+      local m = v % calphanum
+      v = (v - m) / calphanum
+      m = m + 1
+      var = var..string.sub(ALPHANUM, m, m)
+      sz = sz - 1
+    end
+  end
+  var_new = var_new + 1
+  return var, globaluniq[var] ~= nil
+end
+
+----------------------------------------------------------------------
+-- calculate and print some statistics
+-- * probably better in main source, put here for now
+----------------------------------------------------------------------
+
+local function stats_summary(globaluniq, localuniq, afteruniq, option)
+  local print = print or base.print
+  local fmt = string.format
+  local opt_details = option.DETAILS
+  local uniq_g , uniq_li, uniq_lo, uniq_ti, uniq_to,  -- stats needed
+        decl_g, decl_li, decl_lo, decl_ti, decl_to,
+        token_g, token_li, token_lo, token_ti, token_to,
+        size_g, size_li, size_lo, size_ti, size_to
+    = 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
+      0, 0, 0, 0, 0, 0, 0, 0, 0, 0
+  local function avg(c, l)              -- safe average function
+    if c == 0 then return 0 end
+    return l / c
+  end
+  --------------------------------------------------------------------
+  -- collect statistics (note: globals do not have declarations!)
+  --------------------------------------------------------------------
+  for name, uniq in base.pairs(globaluniq) do
+    uniq_g = uniq_g + 1
+    token_g = token_g + uniq.token
+    size_g = size_g + uniq.size
+  end
+  for name, uniq in base.pairs(localuniq) do
+    uniq_li = uniq_li + 1
+    decl_li = decl_li + uniq.decl
+    token_li = token_li + uniq.token
+    size_li = size_li + uniq.size
+  end
+  for name, uniq in base.pairs(afteruniq) do
+    uniq_lo = uniq_lo + 1
+    decl_lo = decl_lo + uniq.decl
+    token_lo = token_lo + uniq.token
+    size_lo = size_lo + uniq.size
+  end
+  uniq_ti = uniq_g + uniq_li
+  decl_ti = decl_g + decl_li
+  token_ti = token_g + token_li
+  size_ti = size_g + size_li
+  uniq_to = uniq_g + uniq_lo
+  decl_to = decl_g + decl_lo
+  token_to = token_g + token_lo
+  size_to = size_g + size_lo
+  --------------------------------------------------------------------
+  -- detailed stats: global list
+  --------------------------------------------------------------------
+  if opt_details then
+    local sorted = {} -- sort table of unique global names by size
+    for name, uniq in base.pairs(globaluniq) do
+      uniq.name = name
+      sorted[#sorted + 1] = uniq
+    end
+    table.sort(sorted,
+      function(v1, v2)
+        return v1.size > v2.size
+      end
+    )
+    local tabf1, tabf2 = "%8s%8s%10s  %s", "%8d%8d%10.2f  %s"
+    local hl = string.rep("-", 44)
+    print("*** global variable list (sorted by size) ***\n"..hl)
+    print(fmt(tabf1, "Token",  "Input", "Input", "Global"))
+    print(fmt(tabf1, "Count", "Bytes", "Average", "Name"))
+    print(hl)
+    for i = 1, #sorted do
+      local uniq = sorted[i]
+      print(fmt(tabf2, uniq.token, uniq.size, avg(uniq.token, uniq.size), uniq.name))
+    end
+    print(hl)
+    print(fmt(tabf2, token_g, size_g, avg(token_g, size_g), "TOTAL"))
+    print(hl.."\n")
+  --------------------------------------------------------------------
+  -- detailed stats: local list
+  --------------------------------------------------------------------
+    local tabf1, tabf2 = "%8s%8s%8s%10s%8s%10s  %s", "%8d%8d%8d%10.2f%8d%10.2f  %s"
+    local hl = string.rep("-", 70)
+    print("*** local variable list (sorted by allocation order) ***\n"..hl)
+    print(fmt(tabf1, "Decl.", "Token",  "Input", "Input", "Output", "Output", "Global"))
+    print(fmt(tabf1, "Count", "Count", "Bytes", "Average", "Bytes", "Average", "Name"))
+    print(hl)
+    for i = 1, #varlist do  -- iterate according to order assigned
+      local name = varlist[i]
+      local uniq = afteruniq[name]
+      local old_t, old_s = 0, 0
+      for j = 1, #localinfo do  -- find corresponding old names and calculate
+        local obj = localinfo[j]
+        if obj.name == name then
+          old_t = old_t + obj.xcount
+          old_s = old_s + obj.xcount * #obj.oldname
+        end
+      end
+      print(fmt(tabf2, uniq.decl, uniq.token, old_s, avg(old_t, old_s),
+                uniq.size, avg(uniq.token, uniq.size), name))
+    end
+    print(hl)
+    print(fmt(tabf2, decl_lo, token_lo, size_li, avg(token_li, size_li),
+              size_lo, avg(token_lo, size_lo), "TOTAL"))
+    print(hl.."\n")
+  end--if opt_details
+  --------------------------------------------------------------------
+  -- display output
+  --------------------------------------------------------------------
+  local tabf1, tabf2 = "%-16s%8s%8s%8s%8s%10s", "%-16s%8d%8d%8d%8d%10.2f"
+  local hl = string.rep("-", 58)
+  print("*** local variable optimization summary ***\n"..hl)
+  print(fmt(tabf1, "Variable",  "Unique", "Decl.", "Token", "Size", "Average"))
+  print(fmt(tabf1, "Types", "Names", "Count", "Count", "Bytes", "Bytes"))
+  print(hl)
+  print(fmt(tabf2, "Global", uniq_g, decl_g, token_g, size_g, avg(token_g, size_g)))
+  print(hl)
+  print(fmt(tabf2, "Local (in)", uniq_li, decl_li, token_li, size_li, avg(token_li, size_li)))
+  print(fmt(tabf2, "TOTAL (in)", uniq_ti, decl_ti, token_ti, size_ti, avg(token_ti, size_ti)))
+  print(hl)
+  print(fmt(tabf2, "Local (out)", uniq_lo, decl_lo, token_lo, size_lo, avg(token_lo, size_lo)))
+  print(fmt(tabf2, "TOTAL (out)", uniq_to, decl_to, token_to, size_to, avg(token_to, size_to)))
+  print(hl.."\n")
+end
+
+----------------------------------------------------------------------
+-- main entry point
+-- * does only local variable optimization for now
+----------------------------------------------------------------------
+
+function optimize(option, _toklist, _seminfolist, _globalinfo, _localinfo)
+  -- set tables
+  toklist, seminfolist, globalinfo, localinfo
+    = _toklist, _seminfolist, _globalinfo, _localinfo
+  var_new = 0                           -- reset variable name allocator
+  varlist = {}
+  ------------------------------------------------------------------
+  -- preprocess global/local tables, handle entropy reduction
+  ------------------------------------------------------------------
+  globaluniq = preprocess(globalinfo)
+  localuniq = preprocess(localinfo)
+  if option["opt-entropy"] then         -- for entropy improvement
+    recalc_for_entropy(option)
+  end
+  ------------------------------------------------------------------
+  -- build initial declared object table, then sort according to
+  -- token count, this might help assign more tokens to more common
+  -- variable names such as 'e' thus possibly reducing entropy
+  -- * an object knows its localinfo index via its 'id' field
+  -- * special handling for "self" special local (parameter) here
+  ------------------------------------------------------------------
+  local object = {}
+  for i = 1, #localinfo do
+    object[i] = localinfo[i]
+  end
+  table.sort(object,                    -- sort largest first
+    function(v1, v2)
+      return v1.xcount > v2.xcount
+    end
+  )
+  ------------------------------------------------------------------
+  -- the special "self" function parameters must be preserved
+  -- * the allocator below will never use "self", so it is safe to
+  --   keep those implicit declarations as-is
+  ------------------------------------------------------------------
+  local temp, j, gotself = {}, 1, false
+  for i = 1, #object do
+    local obj = object[i]
+    if not obj.isself then
+      temp[j] = obj
+      j = j + 1
+    else
+      gotself = true
+    end
+  end
+  object = temp
+  ------------------------------------------------------------------
+  -- a simple first-come first-served heuristic name allocator,
+  -- note that this is in no way optimal...
+  -- * each object is a local variable declaration plus existence
+  -- * the aim is to assign short names to as many tokens as possible,
+  --   so the following tries to maximize name reuse
+  -- * note that we preserve sort order
+  ------------------------------------------------------------------
+  local nobject = #object
+  while nobject > 0 do
+    local varname, gcollide
+    repeat
+      varname, gcollide = new_var_name()  -- collect a variable name
+    until not SKIP_NAME[varname]          -- skip all special names
+    varlist[#varlist + 1] = varname       -- keep a list
+    local oleft = nobject
+    ------------------------------------------------------------------
+    -- if variable name collides with an existing global, the name
+    -- cannot be used by a local when the name is accessed as a global
+    -- during which the local is alive (between 'act' to 'rem'), so
+    -- we drop objects that collides with the corresponding global
+    ------------------------------------------------------------------
+    if gcollide then
+      -- find the xref table of the global
+      local gref = globalinfo[globaluniq[varname].id].xref
+      local ngref = #gref
+      -- enumerate for all current objects; all are valid at this point
+      for i = 1, nobject do
+        local obj = object[i]
+        local act, rem = obj.act, obj.rem  -- 'live' range of local
+        -- if rem < 0, it is a -id to a local that had the same name
+        -- so follow rem to extend it; does this make sense?
+        while rem < 0 do
+          rem = localinfo[-rem].rem
+        end
+        local drop
+        for j = 1, ngref do
+          local p = gref[j]
+          if p >= act and p <= rem then drop = true end  -- in range?
+        end
+        if drop then
+          obj.skip = true
+          oleft = oleft - 1
+        end
+      end--for
+    end--if gcollide
+    ------------------------------------------------------------------
+    -- now the first unassigned local (since it's sorted) will be the
+    -- one with the most tokens to rename, so we set this one and then
+    -- eliminate all others that collides, then any locals that left
+    -- can then reuse the same variable name; this is repeated until
+    -- all local declaration that can use this name is assigned
+    -- * the criteria for local-local reuse/collision is:
+    --   A is the local with a name already assigned
+    --   B is the unassigned local under consideration
+    --   => anytime A is accessed, it cannot be when B is 'live'
+    --   => to speed up things, we have first/last accesses noted
+    ------------------------------------------------------------------
+    while oleft > 0 do
+      local i = 1
+      while object[i].skip do  -- scan for first object
+        i = i + 1
+      end
+      ------------------------------------------------------------------
+      -- first object is free for assignment of the variable name
+      -- [first,last] gives the access range for collision checking
+      ------------------------------------------------------------------
+      oleft = oleft - 1
+      local obja = object[i]
+      i = i + 1
+      obja.newname = varname
+      obja.skip = true
+      obja.done = true
+      local first, last = obja.first, obja.last
+      local xref = obja.xref
+      ------------------------------------------------------------------
+      -- then, scan all the rest and drop those colliding
+      -- if A was never accessed then it'll never collide with anything
+      -- otherwise trivial skip if:
+      -- * B was activated after A's last access (last < act)
+      -- * B was removed before A's first access (first > rem)
+      -- if not, see detailed skip below...
+      ------------------------------------------------------------------
+      if first and oleft > 0 then  -- must have at least 1 access
+        local scanleft = oleft
+        while scanleft > 0 do
+          while object[i].skip do  -- next valid object
+            i = i + 1
+          end
+          scanleft = scanleft - 1
+          local objb = object[i]
+          i = i + 1
+          local act, rem = objb.act, objb.rem  -- live range of B
+          -- if rem < 0, extend range of rem thru' following local
+          while rem < 0 do
+            rem = localinfo[-rem].rem
+          end
+          --------------------------------------------------------
+          if not(last < act or first > rem) then  -- possible collision
+            --------------------------------------------------------
+            -- B is activated later than A or at the same statement,
+            -- this means for no collision, A cannot be accessed when B
+            -- is alive, since B overrides A (or is a peer)
+            --------------------------------------------------------
+            if act >= obja.act then
+              for j = 1, obja.xcount do  -- ... then check every access
+                local p = xref[j]
+                if p >= act and p <= rem then  -- A accessed when B live!
+                  oleft = oleft - 1
+                  objb.skip = true
+                  break
+                end
+              end--for
+            --------------------------------------------------------
+            -- A is activated later than B, this means for no collision,
+            -- A's access is okay since it overrides B, but B's last
+            -- access need to be earlier than A's activation time
+            --------------------------------------------------------
+            else
+              if objb.last and objb.last >= obja.act then
+                oleft = oleft - 1
+                objb.skip = true
+              end
+            end
+          end
+          --------------------------------------------------------
+          if oleft == 0 then break end
+        end
+      end--if first
+      ------------------------------------------------------------------
+    end--while
+    ------------------------------------------------------------------
+    -- after assigning all possible locals to one variable name, the
+    -- unassigned locals/objects have the skip field reset and the table
+    -- is compacted, to hopefully reduce iteration time
+    ------------------------------------------------------------------
+    local temp, j = {}, 1
+    for i = 1, nobject do
+      local obj = object[i]
+      if not obj.done then
+        obj.skip = false
+        temp[j] = obj
+        j = j + 1
+      end
+    end
+    object = temp  -- new compacted object table
+    nobject = #object  -- objects left to process
+    ------------------------------------------------------------------
+  end--while
+  ------------------------------------------------------------------
+  -- after assigning all locals with new variable names, we can
+  -- patch in the new names, and reprocess to get 'after' stats
+  ------------------------------------------------------------------
+  for i = 1, #localinfo do  -- enumerate all locals
+    local obj = localinfo[i]
+    local xref = obj.xref
+    if obj.newname then                 -- if got new name, patch it in
+      for j = 1, obj.xcount do
+        local p = xref[j]               -- xrefs indexes the token list
+        seminfolist[p] = obj.newname
+      end
+      obj.name, obj.oldname             -- adjust names
+        = obj.newname, obj.name
+    else
+      obj.oldname = obj.name            -- for cases like 'self'
+    end
+  end
+  ------------------------------------------------------------------
+  -- deal with statistics output
+  ------------------------------------------------------------------
+  if gotself then  -- add 'self' to end of list
+    varlist[#varlist + 1] = "self"
+  end
+  local afteruniq = preprocess(localinfo)
+  stats_summary(globaluniq, localuniq, afteruniq, option)
+  ------------------------------------------------------------------
+end