mirror of
https://github.com/Sei-Lisa/LSL-PyOptimizer
synced 2025-07-01 23:58:20 +00:00
1111 lines
48 KiB
Python
1111 lines
48 KiB
Python
# (C) Copyright 2015 Sei Lisa. All rights reserved.
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#
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# This file is part of LSL PyOptimizer.
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#
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# LSL PyOptimizer is free software: you can redistribute it and/or
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# modify it under the terms of the GNU General Public License as
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# published by the Free Software Foundation, either version 3 of the
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# License, or (at your option) any later version.
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#
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# LSL PyOptimizer is distributed in the hope that it will be useful,
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# but WITHOUT ANY WARRANTY; without even the implied warranty of
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# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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# GNU General Public License for more details.
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#
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# You should have received a copy of the GNU General Public License
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# along with LSL PyOptimizer. If not, see <http://www.gnu.org/licenses/>.
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# Constant folding and simplification of expressions and statements.
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import lslfuncs
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import math
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from lslparse import warning
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class foldconst(object):
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def isLocalVar(self, node):
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name = node['name']
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scope = node['scope']
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return self.symtab[scope][name]['Kind'] == 'v' \
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and 'Loc' not in self.symtab[scope][name]
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def FoldAndRemoveEmptyStmts(self, lst):
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"""Utility function for elimination of useless expressions in FOR"""
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idx = 0
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while idx < len(lst):
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self.FoldTree(lst, idx)
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self.FoldStmt(lst, idx)
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# If eliminated, it must be totally removed. A ';' won't do.
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if lst[idx]['nt'] == ';':
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del lst[idx]
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else:
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idx += 1
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def FoldStmt(self, parent, index):
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"""Simplify a statement."""
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node = parent[index]
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if node['nt'] == 'EXPR':
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node = node['ch'][0]
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# If the statement is side-effect-free, remove it as it does nothing.
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if 'SEF' in node:
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# Side-effect free means that a statement does nothing except
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# wasting CPU, and can thus be removed without affecting the
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# program. But side effect freedom is propagated from the
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# constituents of the statement, e.g. function calls in expressions
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# or substatements in FOR, or even individual variables.
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#
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# Many library functions like llSameGroup or llGetVel() are
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# side-effect free. Many other functions like llSleep() or
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# llSetScale() are not. User functions may or may not be.
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#
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# Assignments do have side effects, except those of the form x = x.
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# Pre- and post-increment and decrement also have side effects.
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# Type casts do not add side effects. Neither do binary operators.
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parent[index] = {'nt':';', 't':None, 'SEF': True}
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return
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# Post-increments take more space than pre-increments.
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if node['nt'] in ('V++', 'V--'):
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node['nt'] = '++V' if node['nt'] == 'V++' else '--V';
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# Function calls are SEF if both the function and the args are SEF.
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# If the statement is a function call and the function is marked as SEF
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# at this point, it means the arguments are not SEF. Replace the node
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# in that case with a block.
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if node['nt'] == 'FNCALL' and 'SEF' in self.symtab[0][node['name']] and 'Loc' in self.symtab[0][node['name']]:
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parent[index] = {'nt':'{}', 't':None, 'ch':
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[{'nt':'EXPR','t':x['t'],'ch':[x]} for x in node['ch']]}
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self.FoldTree(parent, index)
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return
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def IsBool(self, node):
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"""Some operators return 0 or 1, and that allows simplification of
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boolean expressions. This function returns whether we know for sure
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that the result is boolean.
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"""
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return False # TODO: implement IsBool
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# Ideas include some functions like llSameGroup and llDetectedGroup.
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def FoldCond(self, parent, index):
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"""When we know that the parent is interested only in the truth value
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of the node, we can perform further optimizations. This function deals
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with them.
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"""
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node = parent[index]
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nt = node['nt']
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if nt in ('CONST', 'IDENT', 'FLD'):
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if node['nt'] == 'CONST':
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node['t'] = 'integer'
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node['value'] = -1 if lslfuncs.cond(node['value']) else 0
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return # Nothing to do if it's already simplified.
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child = node['ch'] if 'ch' in node else None
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if nt == '!' and child[0]['nt'] == '!':
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# bool(!!a) equals bool(a)
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parent[index] = child[0]['ch'][0]
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return
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if nt == 'NEG':
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# bool(-a) equals bool(a)
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parent[index] = child[0]
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return
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if nt in self.binary_ops and child[0]['t'] == child[1]['t'] == 'integer':
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if nt == '!=':
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if child[0]['nt'] == 'CONST' and child[0]['value'] == 1 \
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or child[1]['nt'] == 'CONST' and child[1]['value'] == 1:
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# a != 1 -> a - 1 (which FoldTree will transform to ~-a)
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node['nt'] = '-'
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else:
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# This converts != to ^; FoldTree will simplify ^-1 to ~
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# and optimize out ^0.
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node['nt'] = '^'
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self.FoldTree(parent, index)
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elif nt == '==':
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if child[0]['nt'] == 'CONST' and -1 <= child[0]['value'] <= 1 \
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or child[1]['nt'] == 'CONST' and -1 <= child[1]['value'] <= 1:
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# Transform a==b into !(a-b) if either a or b are in [-1, 1]
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parent[index] = {'nt':'!', 't':'integer', 'ch':[node]}
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node['nt'] = '-'
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self.FoldTree(parent, index)
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if nt == '|':
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# In a boolean context, the operands count as booleans.
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self.FoldCond(child, 0)
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self.FoldCond(child, 1)
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a, b = 0, 1
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if child[a]['nt'] == 'CONST':
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a, b = 1, 0
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if child[b]['nt'] == 'CONST' and child[b]['value'] and 'SEF' in child[a]:
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parent[index] = child[b]
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child[b]['value'] = 1
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return
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# TODO: on bitwise OR, detect if both operands are negated.
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# If so treat it as an AND, checking if the operands are boolean
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# to try to simplify them to an expression of the form !(a&b)
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# when possible. Or if one is bool and the other is not, to an
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# expression of the form !(a&-b) (if b is bool).
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# TODO: Convert bool(x < 0) to bool(x & 0x80000000)
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def CopyNode(self, node):
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# This is mainly for simple_expr so no need to go deeper than 1 level.
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ret = node.copy()
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if 'ch' in ret:
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new = []
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for subnode in ret['ch']:
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new.append(self.CopyNode(subnode))
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ret['ch'] = new
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return ret
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def FoldTree(self, parent, index):
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"""Recursively traverse the tree to fold constants, changing it in
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place.
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Also optimizes away IF, WHILE, etc.
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"""
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node = parent[index]
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nt = node['nt']
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child = node['ch'] if 'ch' in node else None
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if nt == 'CONST':
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# Job already done. But mark as side-effect free.
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node['SEF'] = True
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return
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if nt == 'CAST':
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self.FoldTree(child, 0)
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if 'SEF' in child[0]:
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node['SEF'] = True
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if child[0]['nt'] == 'CONST':
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# Enable key constants. We'll typecast them back on output, but
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# this enables some optimizations.
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#if node['t'] != 'key': # key constants not possible
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parent[index] = {'nt':'CONST', 't':node['t'], 'SEF':True,
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'value':lslfuncs.typecast(
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child[0]['value'], self.LSL2PythonType[node['t']])}
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return
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if nt == 'NEG':
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self.FoldTree(child, 0)
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if child[0]['nt'] == 'NEG':
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# Double negation: - - expr --> expr
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node = parent[index] = child[0]['ch'][0]
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child = node['ch'] if 'ch' in node else None
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elif child[0]['nt'] == 'CONST':
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node = parent[index] = child[0]
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node['value'] = lslfuncs.neg(node['value'])
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child = None
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elif 'SEF' in child[0]:
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# propagate Side Effect Free flag
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node['SEF'] = True
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if child and node['nt'] == 'NEG' and child[0]['nt'] == '~':
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track = child[0]['ch'][0]
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const = 1
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while track['nt'] == 'NEG' and track['ch'][0]['nt'] == '~':
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const += 1
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track = track['ch'][0]['ch'][0]
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if const > 2:
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# -~-~-~expr -> expr+3
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node = {'nt':'CONST', 't':'integer', 'SEF':True, 'value':const}
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node = {'nt':'+', 't':'integer', 'ch':[node, track]}
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if 'SEF' in track:
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node['SEF'] = True
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parent[index] = node
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return
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if nt == '!':
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self.FoldTree(child, 0)
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self.FoldCond(child, 0)
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# !! does *not* cancel out (unless in cond), but !!! can be simplified to !
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subexpr = child[0]
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if 'SEF' in subexpr:
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node['SEF'] = True
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if subexpr['nt'] == '!' and subexpr['ch'][0]['nt'] == '!':
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# Simplify !!! to !
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subexpr = child[0] = subexpr['ch'][0]['ch'][0]
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if subexpr['nt'] == 'CONST':
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node = parent[index] = subexpr
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node['value'] = int(not node['value'])
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# TODO: !(i>const) to i<(const+1) if no overflow (4 variants)
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return
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if nt == '~':
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self.FoldTree(child, 0)
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subexpr = child[0]
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if 'SEF' in subexpr:
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node['SEF'] = True
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if subexpr['nt'] == '~':
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# Double negation: ~~expr
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parent[index] = subexpr['ch'][0]
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elif subexpr['nt'] == 'CONST':
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node = parent[index] = child[0]
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node['value'] = ~node['value']
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return
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if nt in self.binary_ops:
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# RTL evaluation
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self.FoldTree(child, 1)
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self.FoldTree(child, 0)
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if 'SEF' in child[0] and 'SEF' in child[1]:
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# Propagate SEF flag if both sides are side-effect free.
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node['SEF'] = True
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optype = node['t']
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lval = child[0]
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ltype = lval['t']
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lnt = lval['nt']
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rval = child[1]
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rtype = rval['t']
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rnt = rval['nt']
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if lnt == rnt == 'CONST':
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op1 = lval['value']
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op2 = rval['value']
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if nt == '+':
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if ltype == rtype == 'string' and not self.addstrings:
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return
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result = lslfuncs.add(op1, op2)
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elif nt == '-':
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result = lslfuncs.sub(op1, op2)
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elif nt == '*':
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result = lslfuncs.mul(op1, op2)
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elif nt == '/':
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try:
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result = lslfuncs.div(op1, op2)
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except lslfuncs.ELSLMathError:
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return
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elif nt == '%':
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try:
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result = lslfuncs.mod(op1, op2)
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except lslfuncs.ELSLMathError:
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return
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elif nt == '<<':
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result = lslfuncs.S32(op1 << (op2 & 31))
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elif nt == '>>':
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result = lslfuncs.S32(op1 >> (op2 & 31))
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elif nt == '==' or nt == '!=':
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result = lslfuncs.compare(op1, op2, Eq = (nt == '=='))
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elif nt in ('<', '<=', '>', '>='):
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if nt in ('>', '<='):
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result = lslfuncs.less(op2, op1)
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else:
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result = lslfuncs.less(op1, op2)
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if nt in ('>=', '<='):
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result = 1-result
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elif nt == '|':
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result = op1 | op2
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elif nt == '^':
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result = op1 ^ op2
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elif nt == '&':
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result = op1 & op2
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elif nt == '||':
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result = int(bool(op1) or bool(op2))
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elif nt == '&&':
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result = int(bool(op1) and bool(op2))
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else:
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assert False, 'Internal error: Operator not found: ' + nt # pragma: no cover
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parent[index] = {'nt':'CONST', 't':node['t'], 'SEF':True, 'value':result}
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return
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# Simplifications for particular operands
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if nt == '-':
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if optype in ('vector', 'rotation'):
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if lnt == 'CONST' and all(component == 0 for component in lval['value']):
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# Change <0,0,0[,0]>-expr -> -expr
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parent[index] = {'nt':'NEG', 't':node['t'], 'ch':[rval]}
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if 'SEF' in rval:
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parent[index]['SEF'] = True
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elif rnt == 'CONST' and all(component == 0 for component in rval['value']):
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# Change expr-<0,0,0[,0]> -> expr
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parent[index] = lval
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return
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# Change - to + - for int/float
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nt = node['nt'] = '+'
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if child[1]['nt'] == 'CONST':
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rval['value'] = lslfuncs.neg(rval['value'])
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else:
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rnt = 'NEG'
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RSEF = 'SEF' in rval
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rval = child[1] = {'nt':rnt, 't':rval['t'], 'ch':[rval]}
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if RSEF:
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rval['SEF'] = True
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# rtype unchanged
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# Fall through to simplify it as '+'
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if nt == '+':
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# Tough one. Remove neutral elements for the diverse types,
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# and more.
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# Addition of integers, strings, and lists is associative.
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# Addition of floats, vectors and rotations would be, except
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# for FP precision.
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# TODO: associative addition of lists
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# Associative lists are trickier, because unlike the others,
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# the types of the operands may not be lists
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# so e.g. list+(integer+integer) != (list+integer)+integer.
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if optype == 'integer' or optype == 'string' and self.addstrings:
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if lnt == '+' and rnt == 'CONST' and lval['ch'][1]['nt'] == 'CONST':
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# (var + ct1) + ct2 -> var + (ct1 + ct2)
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child[1] = {'nt': '+', 't': optype, 'ch':[lval['ch'][1], rval], 'SEF':True}
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lval = child[0] = lval['ch'][0]
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lnt = lval['nt']
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ltype = lval['t']
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rtype = optype
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# Fold the RHS again now that we have it constant
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self.FoldTree(child, 1)
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rval = child[1]
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rnt = rval['nt']
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if optype == 'list' and not (ltype == rtype == 'list'):
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if lnt == 'CONST' and not lval['value']:
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# [] + nonlist -> (list)nonlist
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parent[index] = self.Cast(rval, optype)
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return
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if optype in ('vector', 'rotation'):
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# not much to do with vectors or quaternions either
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if lnt == 'CONST' and all(x == 0 for x in lval['value']):
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# Change <0,0,0[,0]>+expr -> expr
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parent[index] = rval
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elif rnt == 'CONST' and all(x == 0 for x in rval['value']):
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# Change expr+<0,0,0[,0]> -> expr
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parent[index] = lval
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return
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# Can't be key, as no combo of addition operands returns key
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# All these types evaluate to boolean False when they are
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# the neutral addition element.
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if optype in ('string', 'float', 'list'):
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if lnt == 'CONST' and not lval['value']:
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# 0. + expr -> expr
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# "" + expr -> expr
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# [] + expr -> expr
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parent[index] = self.Cast(rval, optype)
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elif rnt == 'CONST' and not rval['value']:
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# expr + 0. -> expr
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# expr + "" -> expr
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# expr + [] -> expr
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parent[index] = self.Cast(lval, optype)
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return
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# Must be two integers. This allows for a number of
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# optimizations. First the most obvious ones.
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if lnt == 'CONST' and lval['value'] == 0:
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parent[index] = rval
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return
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if rnt == 'CONST' and rval['value'] == 0:
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parent[index] = lval
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return
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if lnt != 'CONST' != rnt:
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# Neither is const. Two chances to optimize.
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# 1. -expr + -expr -> -(expr + expr) (saves 1 byte)
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# 2. lvalue + -lvalue -> 0
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# There may be other possibilities for optimization,
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# e.g. (type)ident + -(type)ident but we only do lvalues
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# here. Note these are integers, no NaN involved.
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# TODO: Compare the subtrees if they are SEF. If they are
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# the same subtree, they can cancel out.
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if lnt == rnt == 'NEG':
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node = {'nt':'+', 't':optype, 'ch':[lval['ch'][0], rval['ch'][0]]}
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SEF = 'SEF' in lval['ch'][0] and 'SEF' in rval['ch'][0]
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if SEF:
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node['SEF'] = True
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node = {'nt':'NEG', 't':optype, 'ch':[node]}
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if SEF:
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node['SEF'] = True
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parent[index] = node
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return
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if lnt == 'NEG':
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# Swap to treat always as expr + -expr for simplicity.
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lnt, lval, rnt, rval = rnt, rval, lnt, lval
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if lnt == 'IDENT' and rnt == 'NEG' and rval['ch'][0]['nt'] == 'IDENT' \
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and lval['name'] == rval['ch'][0]['name']:
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# Replace with 0
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parent[index] = {'nt':'CONST', 'SEF': True, 't':optype, 'value':0}
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return
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if lnt == '+' and (lval['ch'][0]['nt'] == 'CONST'
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or lval['ch'][1]['nt'] == 'CONST'):
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# We have expr + const + const or const + expr + const.
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# Addition of integers mod 2^32 is associative and
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# commutative, so constants can be merged.
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if lval['ch'][0]['nt'] == 'CONST':
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rval['value'] = lslfuncs.S32(rval['value'] + lval['ch'][0]['value'])
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lval = child[0] = lval['ch'][1]
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else:
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rval['value'] = lslfuncs.S32(rval['value'] + lval['ch'][1]['value'])
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lval = child[0] = lval['ch'][0]
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lnt = lval['nt']
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if rnt == '+' and (rval['ch'][0]['nt'] == 'CONST'
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or rval['ch'][1]['nt'] == 'CONST'):
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# const + (expr + const) or const + (const + expr)
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# same as above, join them
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|
# FIXME: Isn't this covered by the associative sum above?
|
|
|
|
pass # TODO: implement const + (expr + const) or const + (const + expr)
|
|
|
|
if rnt == 'CONST':
|
|
# Swap the vars to deal with const in lval always
|
|
lval, lnt, rval, rnt = rval, rnt, lval, lnt
|
|
RSEF = 'SEF' in rval
|
|
|
|
if lval['value'] == -1 or lval['value'] == -2:
|
|
if rnt == 'NEG': # Cancel the NEG
|
|
node = {'nt':'~', 't':optype, 'ch':rval['ch']}
|
|
if RSEF:
|
|
node['SEF'] = True
|
|
else: # Add the NEG
|
|
node = {'nt':'NEG', 't':optype, 'ch':[rval]}
|
|
if RSEF:
|
|
node['SEF'] = True
|
|
node = {'nt':'~', 't':optype, 'ch':[node]}
|
|
if RSEF:
|
|
node['SEF'] = True
|
|
if lval['value'] == -2:
|
|
node = {'nt':'NEG', 't':optype, 'ch':[node]}
|
|
if RSEF:
|
|
node['SEF'] = True
|
|
node = {'nt':'~', 't':optype, 'ch':[node]}
|
|
if RSEF:
|
|
node['SEF'] = True
|
|
parent[index] = node
|
|
return
|
|
|
|
if lval['value'] == 1 or lval['value'] == 2:
|
|
if rnt == '~': # Cancel the ~
|
|
node = {'nt':'NEG', 't':optype, 'ch':rval['ch']}
|
|
if RSEF:
|
|
node['SEF'] = True
|
|
else:
|
|
node = {'nt':'~', 't':optype, 'ch':[rval]}
|
|
if RSEF:
|
|
node['SEF'] = True
|
|
node = {'nt':'NEG', 't':optype, 'ch':[node]}
|
|
if RSEF:
|
|
node['SEF'] = True
|
|
if lval ['value'] == 2:
|
|
node = {'nt':'~', 't':optype, 'ch':[node]}
|
|
if RSEF:
|
|
node['SEF'] = True
|
|
node = {'nt':'NEG', 't':optype, 'ch':[node]}
|
|
if RSEF:
|
|
node['SEF'] = True
|
|
parent[index] = node
|
|
return
|
|
|
|
# More than 2 becomes counter-productive.
|
|
|
|
return
|
|
|
|
if nt == '<<' and child[1]['nt'] == 'CONST':
|
|
# Transforming << into multiply saves some bytes.
|
|
if child[1]['value'] & 31:
|
|
# x << 3 --> x * 8
|
|
|
|
# we have {<<, something, {CONST n}}
|
|
# we transform it into {*, something, {CONST n}}
|
|
nt = node['nt'] = '*'
|
|
child[1]['value'] = 1 << (child[1]['value'] & 31)
|
|
|
|
# Fall through to optimize product
|
|
|
|
else: # x << 0 --> x
|
|
parent[index] = child[0]
|
|
return
|
|
|
|
if nt == '%' \
|
|
and child[1]['nt'] == 'CONST' \
|
|
and child[1]['t'] == 'integer' \
|
|
and abs(child[1]['value']) == 1:
|
|
# a%1 -> a&0
|
|
# a%-1 -> a&0
|
|
# (SEF analysis performed below)
|
|
nt = node['nt'] = '&'
|
|
child[1]['value'] = 0
|
|
|
|
|
|
if nt in ('*', '/'):
|
|
# Extract signs outside
|
|
if child[0]['nt'] == 'NEG' or child[1]['nt'] == 'NEG':
|
|
a, b = 0, 1
|
|
if child[b]['nt'] == 'NEG':
|
|
a, b = 1, 0
|
|
child[a] = child[a]['ch'][0]
|
|
parent[index] = node = {'nt':'NEG', 't':node['t'], 'ch':[node]}
|
|
if 'SEF' in node['ch'][0]:
|
|
node['SEF'] = True
|
|
# Fold the new expression
|
|
self.FoldTree(parent, index)
|
|
return
|
|
|
|
# Deal with operands in any order
|
|
a, b = 0, 1
|
|
if child[a]['nt'] == 'CONST' and child[a]['t'] in ('float', 'integer'):
|
|
a, b = 1, 0
|
|
|
|
if child[b]['nt'] == 'CONST':
|
|
val = child[b]['value']
|
|
|
|
# Optimize out signs if possible.
|
|
# Note that (-intvar)*floatconst needs cornermath because
|
|
# -intvar could equal intvar if intvar = -2147483648,
|
|
# so the sign is a no-op and pushing it to floatconst would
|
|
# make the result be different.
|
|
if child[a]['nt'] == 'NEG' \
|
|
and (self.cornermath
|
|
or child[a]['t'] != 'integer'
|
|
or child[b]['t'] != 'float'
|
|
):
|
|
# Expression is of the form (-float)*const or (-float)/const or const/(-float)
|
|
if val != -2147483648 or child[a]['t'] == 'integer': # can't be optimized otherwise
|
|
child[a] = child[a]['ch'][0] # remove NEG
|
|
child[b]['value'] = val = -val
|
|
|
|
# Five optimizations corresponding to -2, -1, 0, 1, 2
|
|
# for product, and two for division:
|
|
# expr * 1 -> expr
|
|
# expr * 0 -> 0 if side-effect free
|
|
# expr * -1 -> -expr
|
|
# ident * 2 -> ident + ident (only if ident is local)
|
|
# ident * -2 -> -(ident + ident) (only if ident is local)
|
|
# expr/1 -> expr
|
|
# expr/-1 -> -expr
|
|
if nt == '*' and child[b]['t'] in ('float', 'integer') \
|
|
and val in (-2, -1, 0, 1, 2) \
|
|
or nt == '/' and b == 1 and val in (-1, 1):
|
|
if val == 1:
|
|
parent[index] = child[a]
|
|
return
|
|
if val == 0:
|
|
if 'SEF' in child[a]:
|
|
parent[index] = child[b]
|
|
return
|
|
if val == -1:
|
|
# Note 0.0*-1 equals -0.0 in LSL, so this is safe
|
|
node = parent[index] = {'nt':'NEG', 't':node['t'], 'ch':[child[a]]}
|
|
if 'SEF' in child[a]:
|
|
node['SEF'] = True
|
|
return
|
|
# only -2, 2 remain
|
|
if child[a]['nt'] == 'IDENT' and self.isLocalVar(child[a]):
|
|
child[b] = child[a].copy()
|
|
node['nt'] = '+'
|
|
if val == -2:
|
|
parent[index] = {'nt':'NEG', 't':node['t'], 'ch':[node]}
|
|
if 'SEF' in node:
|
|
parent[index]['SEF'] = True
|
|
return
|
|
return
|
|
|
|
if nt in ('<=', '>=') or nt == '!=' \
|
|
and child[0]['t'] in ('float', 'integer') \
|
|
and child[1]['t'] in ('float', 'integer'):
|
|
SEF = 'SEF' in node
|
|
node['nt'] = {'<=':'>', '>=':'<', '!=':'=='}[nt]
|
|
node = parent[index] = {'nt':'!', 't':node['t'], 'ch':[node]}
|
|
if SEF:
|
|
node['SEF'] = True
|
|
# Fold the new node
|
|
self.FoldTree(parent, index)
|
|
return
|
|
|
|
if nt in ('<', '>'):
|
|
# TODO: If function domain is -1..INT_MAX, treat <0 as !=-1
|
|
|
|
# i>2147483647 to FALSE if SEF, otherwise convert to a&0
|
|
# i<-2147483648 to FALSE if SEF, otherwise convert to a&0
|
|
a, b = 0, 1
|
|
if child[a]['nt'] == 'CONST':
|
|
a,b = 1,0
|
|
if child[b]['nt'] == 'CONST' and child[a]['t'] == child[b]['t'] == 'integer' \
|
|
and (nt == '>' and child[b]['value'] == 2147483647
|
|
or nt == '<' and child[b]['value'] == -2147483648):
|
|
if 'SEF' in child[a]:
|
|
parent[index] = node = child[b]
|
|
node['value'] = 0
|
|
return
|
|
nt = node['nt'] = '&'
|
|
child[b]['value'] = 0
|
|
# fall through to check for '&'
|
|
|
|
if nt in ('&', '|'):
|
|
# Deal with operands in any order
|
|
a, b = 0, 1
|
|
if child[a]['nt'] == 'CONST' and child[a]['t'] in ('float', 'integer'):
|
|
a, b = 1, 0
|
|
|
|
if child[b]['nt'] == 'CONST':
|
|
val = child[b]['value']
|
|
if val == 0 and nt == '|' or val == -1 and nt == '&':
|
|
# a|0 -> a
|
|
# a&-1 -> a
|
|
parent[index] = child[a]
|
|
return
|
|
if val == -1 and nt == '|' or val == 0 and nt == '&':
|
|
# a|-1 -> -1 if a is SEF
|
|
# a&0 -> 0 if a is SEF
|
|
if 'SEF' in child[a]:
|
|
parent[index] = child[b]
|
|
return
|
|
|
|
if nt == '^':
|
|
a, b = 0, 1
|
|
if child[a]['nt'] == 'CONST':
|
|
a, b = 1, 0
|
|
if child[b]['nt'] == 'CONST' and child[b]['value'] in (0, -1):
|
|
if child[b]['value'] == 0:
|
|
parent[index] = child[a]
|
|
else:
|
|
node['nt'] = '~'
|
|
node['ch'] = [child[a]]
|
|
return
|
|
|
|
if nt == '&&' or nt == '||':
|
|
SEF = 'SEF' in node
|
|
if nt == '||':
|
|
parent[index] = node = {'nt':'!', 't':'integer', 'ch':[
|
|
{'nt':'!', 't':'integer', 'ch':[
|
|
{'nt':'|', 't':'integer', 'ch':[child[0], child[1]]}
|
|
]}]}
|
|
if SEF:
|
|
node['SEF'] = node['ch'][0]['SEF'] = node['ch'][0]['ch'][0]['SEF'] = True
|
|
else:
|
|
parent[index] = node = {'nt':'!', 't':'integer', 'ch':[
|
|
{'nt':'|', 't':'integer', 'ch':[
|
|
{'nt':'!', 't':'integer', 'ch':[child[0]]}
|
|
,
|
|
{'nt':'!', 't':'integer', 'ch':[child[1]]}
|
|
]}]}
|
|
if SEF:
|
|
node['SEF'] = node['ch'][0]['SEF'] = True
|
|
if 'SEF' in node['ch'][0]['ch'][0]['ch'][0]:
|
|
node['ch'][0]['ch'][0]['SEF'] = True
|
|
if 'SEF' in node['ch'][0]['ch'][1]['ch'][0]:
|
|
node['ch'][0]['ch'][1]['SEF'] = True
|
|
# Make another pass with the substitution
|
|
self.FoldTree(parent, index)
|
|
return
|
|
|
|
return
|
|
|
|
if nt in self.assign_ops:
|
|
# Transform the whole thing into a regular assignment, as there are
|
|
# no gains and it simplifies the optimization.
|
|
|
|
# An assignment has no side effects only if it's of the form x = x.
|
|
|
|
if nt != '=':
|
|
# Replace the node with the expression alone
|
|
# e.g. a += b -> a + b
|
|
node['nt'] = nt[:-1]
|
|
|
|
# Linden Craziness: int *= float; is valid (but no other
|
|
# int op= float is). It's actually performed as
|
|
# i = (integer)(i + (f));
|
|
# This breaks equivalence of x op= y as x = x op (y) so we add
|
|
# the explicit type cast here.
|
|
if nt == '*=' and child[0]['t'] == 'integer' and child[1]['t'] == 'float':
|
|
node['t'] = 'float' # Addition shall return float.
|
|
node = self.Cast(node, 'integer')
|
|
|
|
# And wrap it in an assignment.
|
|
child = [child[0].copy(), node]
|
|
node = parent[index] = {'nt':'=', 't':child[0]['t'], 'ch':child}
|
|
|
|
# We have a regular assignment either way now. Simplify the RHS.
|
|
self.FoldTree(node['ch'], 1)
|
|
if child[0]['nt'] == child[1]['nt'] == 'IDENT' \
|
|
and child[1]['name'] == child[0]['name'] \
|
|
and child[1]['scope'] == child[0]['scope'] \
|
|
or child[0]['nt'] == child[1]['nt'] == 'FLD' \
|
|
and child[1]['ch'][0]['name'] == child[0]['ch'][0]['name'] \
|
|
and child[1]['ch'][0]['scope'] == child[0]['ch'][0]['scope'] \
|
|
and child[1]['fld'] == child[0]['fld']:
|
|
node['SEF'] = True
|
|
self.FoldStmt(parent, index)
|
|
return
|
|
|
|
if nt == 'IDENT' or nt == 'FLD':
|
|
node['SEF'] = True
|
|
if self.globalmode:
|
|
ident = child[0] if nt == 'FLD' else node
|
|
# Resolve constant values so they can be optimized
|
|
sym = self.symtab[ident['scope']][ident['name']]
|
|
|
|
defn = self.tree[sym['Loc']]
|
|
assert defn['name'] == ident['name']
|
|
|
|
# Assume we already were there
|
|
if 'ch' in defn:
|
|
val = defn['ch'][0]
|
|
if val['nt'] != 'CONST' or ident['t'] == 'key':
|
|
return
|
|
val = val.copy()
|
|
else:
|
|
val = {'nt':'CONST', 't':defn['t'],
|
|
'value':self.DefaultValues[defn['t']]}
|
|
if nt == 'FLD':
|
|
val = {'nt':'CONST', 't':'float',
|
|
'value':val['value']['xyzs'.index(node['fld'])]}
|
|
parent[index] = val
|
|
return
|
|
|
|
if nt == 'FNCALL':
|
|
SEFargs = True
|
|
CONSTargs = True
|
|
for idx in xrange(len(child)-1, -1, -1):
|
|
self.FoldTree(child, idx)
|
|
# Function is not SEF if any argument is not SEF
|
|
if 'SEF' not in child[idx]:
|
|
SEFargs = False
|
|
# Function is not a constant if any argument is not a constant
|
|
if child[idx]['nt'] != 'CONST':
|
|
CONSTargs = False
|
|
|
|
# TODO: Find some way to convert keys to "" e.g. llListen("", NULL_KEY, "")
|
|
# TODO: Find some way to convert PI to 4 in llSensor[Repeat]
|
|
if 'Fn' in self.symtab[0][node['name']]:
|
|
# Guaranteed to be side-effect free if the children are.
|
|
if SEFargs:
|
|
node['SEF'] = True
|
|
if CONSTargs:
|
|
# Call it
|
|
fn = self.symtab[0][node['name']]['Fn']
|
|
try:
|
|
if node['name'][:10] == 'llDetected':
|
|
value = fn(*tuple(arg['value'] for arg in child),
|
|
event=self.CurEvent)
|
|
else:
|
|
value = fn(*tuple(arg['value'] for arg in child))
|
|
if not self.foldtabs and isinstance(value, unicode) and '\t' in value:
|
|
warning('Tab in function result and foldtabs option not used.')
|
|
return
|
|
parent[index] = {'nt':'CONST', 't':node['t'], 'value':value}
|
|
except lslfuncs.ELSLCantCompute:
|
|
# Don't transform the tree if function is not computable
|
|
pass
|
|
elif node['name'] == 'llGetListLength' and child[0]['nt'] == 'IDENT':
|
|
# Convert llGetListLength(ident) to (ident != [])
|
|
node = {'nt':'CONST', 't':'list', 'value':[]}
|
|
parent[index] = node = {'nt':'!=', 't':'list', 'ch':[child[0], node]}
|
|
elif SEFargs and 'SEF' in self.symtab[0][node['name']]:
|
|
# The function is marked as SEF in the symbol table, and the
|
|
# arguments are all side-effect-free. The result is SEF.
|
|
node['SEF'] = True
|
|
return
|
|
|
|
if nt == 'PRINT':
|
|
self.FoldTree(child, 0)
|
|
# PRINT is considered to have side effects. If it's there, assume
|
|
# there's a reason.
|
|
return
|
|
|
|
if nt == 'EXPR':
|
|
self.FoldTree(child, 0)
|
|
if 'SEF' in child[0]:
|
|
node['SEF'] = True
|
|
return
|
|
|
|
if nt == 'FNDEF':
|
|
# used when folding llDetected* function calls
|
|
if 'scope' in node:
|
|
# function definition
|
|
self.CurEvent = None
|
|
else:
|
|
# event definition
|
|
self.CurEvent = node['name']
|
|
self.FoldTree(child, 0)
|
|
# TODO: This works, but analysis of code paths is DCR's thing
|
|
# and this is incomplete, e.g. x(){{return;}} is not detected.
|
|
while 'ch' in child[0] and child[0]['ch']:
|
|
last = child[0]['ch'][-1]
|
|
if last['nt'] != 'RETURN' or 'ch' in last:
|
|
break
|
|
del child[0]['ch'][-1]
|
|
if 'SEF' in child[0]:
|
|
node['SEF'] = True
|
|
if node['name'] in self.symtab[0]:
|
|
# Mark the symbol table entry if it's not an event.
|
|
self.symtab[0][node['name']]['SEF'] = True
|
|
return
|
|
|
|
if nt in ('VECTOR', 'ROTATION', 'LIST'):
|
|
isconst = True
|
|
issef = True
|
|
for idx in xrange(len(child)-1, -1, -1):
|
|
self.FoldTree(child, idx)
|
|
if child[idx]['nt'] != 'CONST':
|
|
isconst = False
|
|
if 'SEF' not in child[idx]:
|
|
issef = False
|
|
if isconst:
|
|
value = [elem['value'] for elem in child]
|
|
if nt == 'VECTOR':
|
|
value = lslfuncs.Vector([lslfuncs.ff(x) for x in value])
|
|
elif nt == 'ROTATION':
|
|
value = lslfuncs.Quaternion([lslfuncs.ff(x) for x in value])
|
|
parent[index] = {'nt':'CONST', 'SEF':True, 't':node['t'],
|
|
'value':value}
|
|
return
|
|
if issef:
|
|
node['SEF'] = True
|
|
return
|
|
|
|
if nt == 'STDEF':
|
|
for idx in xrange(len(child)):
|
|
self.FoldTree(child, idx)
|
|
return
|
|
|
|
if nt == '{}':
|
|
idx = 0
|
|
issef = True
|
|
while idx < len(child):
|
|
self.FoldTree(child, idx)
|
|
self.FoldStmt(child, idx)
|
|
if 'SEF' not in child[idx]:
|
|
issef = False
|
|
if child[idx]['nt'] == ';' \
|
|
or child[idx]['nt'] == '{}' and not child[idx]['ch']:
|
|
del child[idx]
|
|
else:
|
|
if 'StSw' in child[idx]:
|
|
node['StSw'] = True
|
|
idx += 1
|
|
if issef:
|
|
node['SEF'] = True
|
|
return
|
|
|
|
if nt == 'IF':
|
|
# TODO: Swap IF/ELSE if both present and cond starts with !
|
|
self.FoldTree(child, 0)
|
|
self.FoldCond(child, 0)
|
|
if child[0]['nt'] == 'CONST':
|
|
# We might be able to remove one of the branches.
|
|
if child[0]['value']:
|
|
self.FoldTree(child, 1)
|
|
# If it has a state switch, the if() must be preserved
|
|
# (but the else branch may be removed).
|
|
if 'StSw' in child[1]:
|
|
# TODO: Get rid of StSw craziness and make another pass
|
|
# to put them under conditionals if present (if bald
|
|
# state switches are present, it means they are the
|
|
# result of optimization so they must be wrapped in an
|
|
# IF statement). The current approach leaves unnecessary
|
|
# IFs behind.
|
|
if len(child) == 3:
|
|
del child[2] # Delete ELSE if present
|
|
return
|
|
else:
|
|
self.FoldStmt(child, 1)
|
|
parent[index] = child[1]
|
|
return
|
|
elif len(child) == 3:
|
|
self.FoldTree(child, 2)
|
|
self.FoldStmt(child, 2)
|
|
parent[index] = child[2]
|
|
return
|
|
else:
|
|
# No ELSE branch, replace the statement with an empty one.
|
|
parent[index] = {'nt':';', 't':None, 'SEF':True}
|
|
return
|
|
else:
|
|
self.FoldTree(child, 1)
|
|
self.FoldStmt(child, 1)
|
|
if len(child) > 2:
|
|
self.FoldTree(child, 2)
|
|
self.FoldStmt(child, 2)
|
|
if child[2]['nt'] == ';' \
|
|
or child[2]['nt'] == '{}' and not child[2]['ch']:
|
|
# no point in "... else ;" - remove else branch
|
|
del child[2]
|
|
if all('SEF' in subnode for subnode in child):
|
|
node['SEF'] = True
|
|
return
|
|
|
|
if nt == 'WHILE':
|
|
# Loops are not considered side-effect free. If the expression is
|
|
# TRUE, it's definitely not SEF. If it's FALSE, it will be optimized
|
|
# anyway. Otherwise we just don't know if it may be infinite, even
|
|
# if every component is SEF.
|
|
|
|
self.FoldTree(child, 0)
|
|
self.FoldCond(child, 0)
|
|
if child[0]['nt'] == 'CONST':
|
|
# See if the whole WHILE can be eliminated.
|
|
if child[0]['value']:
|
|
# Endless loop which must be kept.
|
|
# Recurse on the statement.
|
|
self.FoldTree(child, 1)
|
|
self.FoldStmt(child, 1)
|
|
else:
|
|
# Can be removed.
|
|
parent[index] = {'nt':';', 't':None, 'SEF':True}
|
|
return
|
|
else:
|
|
self.FoldTree(child, 1)
|
|
self.FoldStmt(child, 1)
|
|
return
|
|
|
|
if nt == 'DO':
|
|
self.FoldTree(child, 0) # This one is always executed.
|
|
self.FoldStmt(child, 0)
|
|
self.FoldTree(child, 1)
|
|
self.FoldCond(child, 1)
|
|
# See if the latest part is a constant.
|
|
if child[1]['nt'] == 'CONST':
|
|
if not child[1]['value']:
|
|
# Only one go. Replace with the statement(s).
|
|
parent[index] = child[0]
|
|
return
|
|
|
|
if nt == 'FOR':
|
|
assert child[0]['nt'] == 'EXPRLIST'
|
|
assert child[2]['nt'] == 'EXPRLIST'
|
|
self.FoldAndRemoveEmptyStmts(child[0]['ch'])
|
|
|
|
self.FoldTree(child, 1) # Condition.
|
|
self.FoldCond(child, 1)
|
|
if child[1]['nt'] == 'CONST':
|
|
# FOR is delicate. It can have multiple expressions at start.
|
|
# And if there is more than one, these expressions will need a
|
|
# new block, which means new scope, which is dangerous.
|
|
# They are expressions, no declarations or labels allowed, thus
|
|
# no new identifiers, but it still feels uneasy.
|
|
if child[1]['value']:
|
|
# Endless loop. Traverse the loop and the iterator.
|
|
self.FoldTree(child, 3)
|
|
self.FoldStmt(child, 3)
|
|
self.FoldAndRemoveEmptyStmts(child[2]['ch'])
|
|
else:
|
|
# Convert expression list to code block.
|
|
exprlist = []
|
|
for expr in child[0]['ch']:
|
|
# Fold into expression statements.
|
|
exprlist.append({'nt':'EXPR', 't':expr['t'], 'ch':[expr]})
|
|
# returns type None, as FOR does
|
|
if exprlist:
|
|
# We're in the case where there are expressions. If any
|
|
# remain, they are not SEF (or they would have been
|
|
# removed earlier) so don't mark this node as SEF.
|
|
parent[index] = {'nt':'{}', 't':None, 'ch':exprlist}
|
|
else:
|
|
parent[index] = {'nt':';', 't':None, 'SEF': True}
|
|
return
|
|
else:
|
|
self.FoldTree(child, 3)
|
|
self.FoldStmt(child, 3)
|
|
self.FoldAndRemoveEmptyStmts(child[2]['ch'])
|
|
return
|
|
|
|
if nt == 'RETURN':
|
|
if child:
|
|
self.FoldTree(child, 0)
|
|
return
|
|
|
|
if nt == 'DECL':
|
|
if child:
|
|
# Check if child is a simple_expr. If it is, then we keep the
|
|
# original attached to the folded node to use it in the output.
|
|
if child[0].pop('Simple', False):
|
|
orig = self.CopyNode(child[0])
|
|
self.FoldTree(child, 0)
|
|
child[0]['orig'] = orig
|
|
else:
|
|
self.FoldTree(child, 0)
|
|
# Remove assignment if integer zero.
|
|
if node['t'] == 'integer' and child[0]['nt'] == 'CONST' \
|
|
and not child[0]['value']:
|
|
del node['ch']
|
|
child = None
|
|
return
|
|
else:
|
|
# Add assignment if vector, rotation or float.
|
|
if node['t'] in ('float', 'vector', 'rotation'):
|
|
typ = node['t']
|
|
node['ch'] = [{'nt':'CONST', 't':typ, 'SEF': True,
|
|
'value': 0.0 if typ == 'float' else
|
|
lslfuncs.ZERO_VECTOR if typ == 'vector' else
|
|
lslfuncs.ZERO_ROTATION}]
|
|
# Declarations always have side effects.
|
|
return
|
|
|
|
if nt == 'STSW':
|
|
# State switch always has side effects.
|
|
node['StSw'] = True
|
|
return
|
|
|
|
if nt == 'SUBIDX':
|
|
# Recurse to every child. It's SEF if all children are.
|
|
idx = 0
|
|
issef = True
|
|
while idx < len(child):
|
|
self.FoldTree(child, idx)
|
|
if 'SEF' not in child[idx]:
|
|
issef = False
|
|
idx += 1
|
|
if issef:
|
|
node['SEF'] = True
|
|
return
|
|
|
|
if nt == ';':
|
|
node['SEF'] = True
|
|
return
|
|
|
|
if nt in ('JUMP', '@', 'V++', 'V--', '--V', '++V', 'LAMBDA'):
|
|
# Except LAMBDA, these all have side effects, as in, can't be
|
|
# eliminated as statements.
|
|
# LAMBDA can't be eliminated without scrolling Loc's.
|
|
return
|
|
|
|
assert False, 'Internal error: This should not happen, node type = ' \
|
|
+ nt # pragma: no cover
|
|
|
|
def IsValidGlobalIdOrConst(self, node):
|
|
# inf and nan can't be represented as a simple constant
|
|
return not (node['nt'] == 'CONST' and node['t'] == 'float'
|
|
and (math.isinf(node['value'])
|
|
or math.isnan(node['value'])))
|
|
|
|
def IsValidGlobalConstant(self, decl):
|
|
if 'ch' not in decl:
|
|
return True
|
|
expr = decl['ch'][0]
|
|
if expr['nt'] in ('CONST', 'IDENT'):
|
|
return self.IsValidGlobalIdOrConst(expr)
|
|
if expr['nt'] not in ('VECTOR', 'ROTATION', 'LIST'):
|
|
return False
|
|
return all(elem['nt'] in ('CONST', 'IDENT')
|
|
and self.IsValidGlobalIdOrConst(elem)
|
|
for elem in expr['ch'])
|
|
|
|
def FoldScript(self, warningpass = True):
|
|
"""Optimize the symbolic table symtab in place. Requires a table of
|
|
predefined functions for folding constants.
|
|
"""
|
|
self.globalmode = False
|
|
|
|
tree = self.tree
|
|
self.CurEvent = None
|
|
|
|
# Constant folding pass. It does some other optimizations along the way.
|
|
for idx in xrange(len(tree)):
|
|
if tree[idx]['nt'] == 'DECL':
|
|
self.globalmode = True
|
|
self.FoldTree(tree, idx)
|
|
self.globalmode = False
|
|
if warningpass and not self.IsValidGlobalConstant(tree[idx]):
|
|
warning('Expression does not resolve to a simple constant.')
|
|
else:
|
|
self.FoldTree(tree, idx)
|