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elua/mkfs.py
Bogdan Marinescu d54659b572 RAM optimizations: pseudo RO strings, functions in Flash
This patch adds more RAM optimizations to eLua:

- direct file memory mapping: files in ROMFS will be read directly from Flash,
  without allocating any additional buffers. This doesn't help with RAM
  consumption in itself, but enables the set of optimizations below.

- pseudo read-only strings. These are still TStrings, but the actual string
  content can point directly to Flash. Original Lua strings are kept in
  TStrings structures (lobject.h):

  typedef union TString {
    L_Umaxalign dummy;  /* ensures maximum alignment for strings */
    struct {
      CommonHeader;
      lu_byte reserved;
      unsigned int hash;
      size_t len;
    } tsv;
  } TString;

  The actual string content comes right after the union TString above.
  Pseudo RO strings have the same header, but instead of having the string
  content after TString, they have a pointer that points to the actual
  string content (which should exist in a RO memory (Flash) that is directly
  accesbile from the MCU bus (like its internal Flash memory)). lua_newlstr
  detects automatically if it should create a regular string or a pseudo RO
  string by checking if the string pointer comes from the Flash region of the
  MCU. This optimization works for both precompiled (.lc) files that exist in
  ROMFS and for internal Lua strings (C code).

- functions in Flash: for precompiled (.lc) files that exist in ROMFS, the code
  of the functions and a part of the debug information will be read directly
  from Flash.

- ROMFS was changed to support files that are larger than 2**16 bytes and it
  aligns all its files to an offset which is a multiple of 4 in order to prevent
  data alignment issues with precompiled Lua code.

- the Lua bytecode dumper was changed to align all the instructions in a Lua
  function and a part of the debug information to an offset which is a multiple
  of 4. This might slightly increase the size of the precompiled Lua file.

These changes were succesfully checked against the Lua 5.1 test suite.
These changes were tested in eLua on LM3S and AVR32.
2012-05-10 00:39:42 +03:00

143 lines
4.4 KiB
Python

# A script to convert an entire directory to a C array, in the "romfs" format
import os, sys
import re
import struct
_crtline = ' '
_numdata = 0
_bytecnt = 0
_fcnt = 0
maxlen = 30
alignment = 4
# Line output function
def _add_data( data, outfile, moredata = True ):
global _crtline, _numdata, _bytecnt, _fcnt
_bytecnt = _bytecnt + 1
_fcnt = _fcnt + 1
if moredata:
_crtline = _crtline + "0x%02X, " % data
else:
_crtline = _crtline + "0x%02X" % data
_numdata = _numdata + 1
if _numdata == 16 or not moredata:
outfile.write( _crtline + '\n' )
_crtline = ' '
_numdata = 0
# dirname - the directory where the files are located.
# outname - the name of the C output
# flist - list of files
# mode - preprocess the file system:
# "verbatim" - copy the files directly to the FS as they are
# "compile" - precompile all files to Lua bytecode and then copy them
# "compress" - keep the source code, but compress it with LuaSrcDiet
# compcmd - the command to use for compiling if "mode" is "compile"
# Returns True for OK, False for error
def mkfs( dirname, outname, flist, mode, compcmd ):
# Try to create the output files
outfname = outname + ".h"
try:
outfile = file( outfname, "wb" )
except:
print "Unable to create output file"
return False
global _crtline, _numdata, _bytecnt, _fcnt
_crtline = ' '
_numdata = 0
_bytecnt = 0
# Generate headers
outfile.write( "// Generated by mkfs.py\n// DO NOT MODIFY\n\n" )
outfile.write( "#ifndef __%s_H__\n#define __%s_H__\n\n" % ( outname.upper(), outname.upper() ) )
outfile.write( "const unsigned char %s_fs[] = \n{\n" % ( outname.lower() ) )
# Process all files
for fname in flist:
if len( fname ) > maxlen:
print "Skipping %s (name longer than %d chars)" % ( fname, maxlen )
continue
# Get actual file name
realname = os.path.join( dirname, fname )
# Ensure it actually is a file
if not os.path.isfile( realname ):
print "Skipping %s ... (not found or not a regular file)" % fname
continue
# Try to open and read the file
try:
crtfile = file( realname, "rb" )
except:
outfile.close()
os.remove( outfname )
print "Unable to read %s" % fname
return False
# Do we need to process the file?
fextpart = ''
if mode == "compile" or mode == "compress":
fnamepart, fextpart = os.path.splitext( realname )
if mode == "compress":
newext = ".lua.tmp"
else:
newext = ".lc"
if fextpart == ".lua":
newname = fnamepart + newext
if mode == "compress":
print "Compressing %s to %s ..." % ( realname, newname )
else:
print "Cross compiling %s to %s ..." % ( realname, newname )
os.system( compcmd % ( newname, realname ) )
# TODO: this assumes that the cross compiler ended OK
crtfile.close()
try:
crtfile = file( newname, "rb" )
except:
outfile.close()
os.remove( outfname )
print "Unable to read %s" % newname
return False
if mode == "compile":
fnamepart, fextpart = os.path.splitext( fname )
fname = fnamepart + ".lc"
filedata = crtfile.read()
crtfile.close()
if fextpart == ".lua" and mode != "verbatim":
os.remove( newname )
# Write name, size, id, numpars
_fcnt = 0
for c in fname:
_add_data( ord( c ), outfile )
_add_data( 0, outfile ) # ASCIIZ
size_ll = len( filedata ) & 0xFF
size_lh = ( len( filedata ) >> 8 ) & 0xFF
size_hl = ( len( filedata ) >> 16 ) & 0xFF
size_hh = ( len( filedata ) >> 24 ) & 0xFF
_add_data( size_ll, outfile )
_add_data( size_lh, outfile )
_add_data( size_hl, outfile )
_add_data( size_hh, outfile )
# Round to a multiple of 4
actual = len( filedata )
while _bytecnt & ( alignment - 1 ) != 0:
_add_data( 0, outfile )
actual = actual + 1
# Then write the rest of the file
for c in filedata:
_add_data( ord( c ), outfile )
# Report
print "Encoded file %s (%d bytes real size, %d bytes after rounding, %d bytes total)" % ( fname, len( filedata ), actual, _fcnt )
# All done, write the final "0" (terminator)
_add_data( 0, outfile, False )
outfile.write( "};\n\n#endif\n" );
outfile.close()
print "Done, total size is %d bytes" % _bytecnt
return True