Re: Lua "amalgamation" for 5-10% speed improvement and ease of use

[dcharno <dcharno@...>]

> I was reading the following page related to the SQLite project: http://www.sqlite.org/cvstrac/wiki?p=TheAmalgamation
> and found this:
> "In addition to making SQLite easier to incorporate into other projects, the amalgamation also makes it run faster. Many compilers are able to do additional optimizations on code when it is contained with in a single translation unit such as it is in the amalgamation. We have measured performance improvements of between 5 and 10% when we use the amalgamation to compile SQLite rather than individual source files."

This is an old thread, but ...

After using SQLite in a number of projects I really came to appreciate 
the convenience of the amalgamation approach. etc/all.c helps quite a 
bit, but it is nice dealing with fewer files.

The attached script makes amalgamated C and header files based upon 
all.c. To use them in a project, just build in am-lua.c and include 
am-lua.h.  Maybe someone else finds it useful


--
-- Copy inputs to output, inlining any Lua #include once
--

local PREFIX = "am-"
local SRC_PATH = "../src/"

function CreateAmalgamation(ofilename, files)

  local out = assert(io.open(ofilename, "w"))
  local headers = { ["lua.c"]=true }

  function CopyWithInline(filename)
  if headers[filename] == nil then
    headers[filename] = true

    local inp = assert(io.open(SRC_PATH .. filename, "r"))
      for l in inp:lines() do
        local inc = l:match('#include "([^"]+)"')
        if inc and (inc ~= "luaconf.h") then
          CopyWithInline(inc)
        else
          out:write(l .. "\n")
        end
      end
    end
  end

  for _, file in ipairs(files) do
    CopyWithInline(file)
  end

end

CreateAmalgamation(PREFIX.."lua.c", {"../etc/all.c"})
CreateAmalgamation(PREFIX.."lua.h", { "lua.h", "lauxlib.h", "lualib.h"})