LSL-PyOptimizer/lslopt/lslrenamer.py
Sei Lisa d03de9a6be Add --blacklist, to blacklist constants; defauls to NAK,JSON_*
Closes #30, but not the general problem of control characters in the source.
2024-05-28 20:19:10 +02:00

219 lines
9.7 KiB
Python

# (C) Copyright 2015-2024 Sei Lisa. All rights reserved.
#
# This file is part of LSL PyOptimizer.
#
# LSL PyOptimizer is free software: you can redistribute it and/or
# modify it under the terms of the GNU General Public License as
# published by the Free Software Foundation, either version 3 of the
# License, or (at your option) any later version.
#
# LSL PyOptimizer is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with LSL PyOptimizer. If not, see <http://www.gnu.org/licenses/>.
# This module renames all kinds of variables. Global variables, user functions,
# state names, event names and function/event parameters all take memory space,
# so shrinking the identifiers as much as possible, when possible (i.e. not for
# events or the default state), ensures their memory usage will be minimized.
# It also reuses some preexisting names. Locals are renamed also so that they
# don't stand in the way of globals.
#
# A side effect of this change is that the script becomes unreadable gibberish.
from strutil import xrange
class renamer(object):
CharSet1 = '_ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz'
CharSet2 = '0123456789_ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz'
# As a special case, 'Pop' is not a keyword, but it's one of the predefined
# identifiers, therefore it must not be generated by GetNextShortest
# because it's already in the list of identifiers available from the start.
Kws = frozenset({'do', 'if', 'PI',
'for', 'key', 'EOF', 'Pop',
'jump', 'else', 'list', 'TRUE', 'LOOP', 'case'
})
def GetNextShortest(self):
"""Generate the next shortest possible identifier"""
while True:
ret = self.CharSet1[self.WordFirstChar]
for idx in self.WordRestOfChars:
ret += self.CharSet2[idx]
self.WordFirstChar += 1
if self.WordFirstChar >= len(self.CharSet1):
self.WordFirstChar = 0
for idx in xrange(len(self.WordRestOfChars)):
if self.WordRestOfChars[idx] < len(self.CharSet2)-1:
self.WordRestOfChars[idx] += 1
break
self.WordRestOfChars[idx] = 0
else:
self.WordRestOfChars.append(0)
if ret not in self.Kws and ret not in self.UsedNames:
return ret
def ShrinkNames(self, UsableAsGlobals = None, UsableAsParams = None):
"""Implements the shrinknames option."""
self.WordFirstChar = 0
self.WordRestOfChars = []
# Names that can be reused without penalty. This initial set is there
# since the beginning. Others are created depending on the code
# (e.g. Key when there are keys), but we don't take too many risks.
ReusableNames = set(['LslLibrary', 'Library', 'LslUserScript',
'System', 'UThread', 'UThreadStackFrame', 'Pop',
'IsRestoring', 'IsSaveDue', 'ResumeVoid',
])
if UsableAsGlobals is not None:
ReusableNames |= UsableAsGlobals
# Names from ReusableNames that have already been used
self.UsedNames = set()
# Make a preliminary pass to separate the symbols into three categories
globalvars = []
states = []
functions = []
globaldefs = self.symtab[0]
for name in globaldefs:
if name == -1: continue
kind = globaldefs[name]['Kind']
if kind == 's':
states.append(name)
elif kind == 'f':
if 'Loc' in globaldefs[name]:
functions.append(name)
elif kind == 'v':
globalvars.append(name)
elif kind == 'c':
pass
else:
assert False, 'Invalid kind at this scope: ' \
+ kind # pragma: no cover
# We make four passes, one for states, then function names, then
# global names, then parameter names and locals, in that order.
# State names are usable as short identifiers for parameters.
stateNames = []
for name in states:
# States have top priority. Here's why. An internal event function
# name is made by concatenating an 'e', then the state name, then
# the event name, e.g. edefaultstate_entry. Since a new identifier
# having part of the state name is created for every event in that
# state, the shorter the state name, the lesser bytes it will use.
# Furthermore, a state switch instruction also adds a Unicode
# string (all other identifier names use one-byte strings), which
# is the more reason to shorten it as much as possible.
#
# Unfortunately, there isn't much that can be done about 'default'.
#
# The good side is that we get to reuse these names for variables
# without using extra space and without wasting single or double
# letter identifiers.
entry = globaldefs[name]
if name != 'default':
name = entry['NewName'] = self.GetNextShortest()
stateNames.append(name)
# Find also the event names it uses, to add them for reuse.
for node in self.tree[entry['Loc']].ch:
assert node.nt == 'FNDEF'
event_name = node.name
# These events have their names translated.
if event_name == 'on_rez':
event_name = 'rez'
if event_name == 'listen':
event_name = 'chat'
if event_name == 'run_time_permissions':
# LSO internally translates run_time_permissions to 'chat'.
# But it doesn't include identifiers in the object anyway,
# so this is here for documentation purposes only.
#if lslcommon.LSO:
# event_name = 'chat'
#else:
event_name = 'run_time_perms'
if event_name == 'remote_data':
event_name = 'remote_event'
ReusableNames.add('e' + name + event_name)
del states
for name in functions:
# Assign a new name. Internally, function names get a 'g' prepended
# to them, so these are candidates for reuse too.
# Unfortunately, we won't find any reusable name starting with 'g'
# this early, so no point in searching.
short = globaldefs[name]['NewName'] = self.GetNextShortest()
ReusableNames.add('g' + short)
del functions
for name in globalvars:
# First, check if we have reusable names available.
if ReusableNames:
short = ReusableNames.pop()
self.UsedNames.add(short)
else:
short = self.GetNextShortest()
globaldefs[name]['NewName'] = short
# Do the same for function and event parameter names. Pure locals get
# long distinct names.
if UsableAsParams is not None:
ReusableNames |= UsableAsParams
First = True
restart = self.WordFirstChar
restartReusable = ReusableNames
ReusableNames = restartReusable.copy()
restartState = stateNames;
stateNames = restartState[:]
restartUsed = self.UsedNames;
self.UsedNames = restartUsed.copy()
for table in self.symtab:
if First:
First = False
# Skip globals
continue
InParams = False
for name,sym in table.items():
if name == -1: continue
if sym['Kind'] != 'v':
assert sym['Kind'] == 'l'
name = name # trick python to not optimize out the jump
continue
if 'Param' in sym:
if not InParams:
# Restart at every new parameter table.
# Parameter tables are isolated from each other.
InParams = True
self.WordFirstChar = restart
ReusableNames = restartReusable.copy()
stateNames = restartState[:]
self.UsedNames = restartUsed.copy()
# Same procedure as for global vars
if ReusableNames:
short = ReusableNames.pop()
self.UsedNames.add(short)
elif stateNames:
short = stateNames.pop()
# No need to add it to UsedNames because
# GetNextShortest will always start past it anyway.
else:
short = self.GetNextShortest()
table[name]['NewName'] = short
else:
# Generate new identifier, by prepending the four character
# string 'loc_'. This generates identifiers with five chars
# or more. We assume that is enough for them to stay safe
# from name collisions with globals and parameter names.
# Four letters allow for more than 1.4 million identifiers.
unique = 'loc_' + name
table[name]['NewName'] = unique
del globalvars