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223 lines
12 KiB
Python
223 lines
12 KiB
Python
"""
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Programming Language for 6502/6510 microprocessors, codename 'Sick'
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This is the part of the compiler/optimizer that simplifies expressions by doing
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'constant folding' - replacing expressions with constant, compile-time precomputed values.
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Written by Irmen de Jong (irmen@razorvine.net) - license: GNU GPL 3.0
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"""
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import sys
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from .plylex import SourceRef
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from .datatypes import VarType
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from .plyparse import *
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def handle_internal_error(exc: Exception, msg: str = "") -> None:
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out = sys.stdout
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if out.isatty():
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print("\x1b[1m", file=out)
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print("\nERROR: internal parser/optimizer error: ", exc, file=out)
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if msg:
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print(" Message:", msg, end="\n\n")
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if out.isatty():
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print("\x1b[0m", file=out, end="", flush=True)
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raise exc
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class ConstantFold:
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def __init__(self, mod: Module) -> None:
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self.num_warnings = 0
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self.module = mod
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self.optimizations_performed = False
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def fold_constants(self, once: bool=False) -> None:
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self.num_warnings = 0
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if once:
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self._constant_folding()
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else:
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self.optimizations_performed = True
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# keep optimizing as long as there were changes made
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while self.optimizations_performed:
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self.optimizations_performed = False
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self._constant_folding()
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def _constant_folding(self) -> None:
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for expression in self.module.all_nodes(Expression):
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if expression.parent is None or expression.parent.parent is None:
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# stale expression node (was part of an expression that was constant-folded away)
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continue
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if isinstance(expression, LiteralValue):
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continue
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try:
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evaluated = self._process_expression(expression) # type: ignore
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if evaluated is not expression:
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# replace the node with the newly evaluated result
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parent = expression.parent
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parent.replace_node(expression, evaluated)
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self.optimizations_performed = True
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except ParseError:
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raise
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except Exception as x:
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handle_internal_error(x, "process_expressions of node {}".format(expression))
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def _process_expression(self, expr: Expression) -> Expression:
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# process/simplify all expressions (constant folding etc)
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if expr.is_lhs:
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if isinstance(expr, (Register, SymbolName, Dereference)):
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return expr
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raise ParseError("invalid lhs expression type", expr.sourceref)
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result = None # type: Expression
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if expr.is_compiletime_const():
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result = self._process_constant_expression(expr, expr.sourceref)
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else:
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result = self._process_dynamic_expression(expr, expr.sourceref)
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result.parent = expr.parent
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return result
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def _process_constant_expression(self, expr: Expression, sourceref: SourceRef) -> LiteralValue:
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# the expression must result in a single (constant) value (int, float, whatever) wrapped as LiteralValue.
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if isinstance(expr, LiteralValue):
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return expr
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try:
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return LiteralValue(value=expr.const_value(), sourceref=sourceref) # type: ignore
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except NotCompiletimeConstantError:
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pass
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if isinstance(expr, SymbolName):
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value = check_symbol_definition(expr.name, expr.my_scope(), expr.sourceref)
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if isinstance(value, VarDef):
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if value.vartype == VarType.MEMORY:
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raise ExpressionEvaluationError("can't take a memory value, must be a constant", expr.sourceref)
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value = value.value
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if isinstance(value, ExpressionWithOperator):
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raise ExpressionEvaluationError("circular reference?", expr.sourceref)
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elif isinstance(value, LiteralValue):
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return value
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elif isinstance(value, (int, float, str, bool)):
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raise TypeError("symbol value node should not be a python primitive value", expr)
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else:
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raise ExpressionEvaluationError("constant symbol required, not {}".format(value.__class__.__name__), expr.sourceref)
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elif isinstance(expr, AddressOf):
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assert isinstance(expr.name, str)
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value = check_symbol_definition(expr.name, expr.my_scope(), expr.sourceref)
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if isinstance(value, VarDef):
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if value.vartype == VarType.MEMORY:
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if isinstance(value.value, LiteralValue):
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return value.value
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else:
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raise ExpressionEvaluationError("constant literal value required", value.sourceref)
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if value.vartype == VarType.CONST:
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raise ExpressionEvaluationError("can't take the address of a constant", expr.sourceref)
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raise ExpressionEvaluationError("address-of this {} isn't a compile-time constant"
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.format(value.__class__.__name__), expr.sourceref)
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else:
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raise ExpressionEvaluationError("constant address required, not {}"
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.format(value.__class__.__name__), expr.sourceref)
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elif isinstance(expr, SubCall):
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if isinstance(expr.target, SymbolName): # 'function(1,2,3)'
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funcname = expr.target.name
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if funcname in math_functions or funcname in builtin_functions:
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func_args = []
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for a in (self._process_constant_expression(callarg.value, sourceref) for callarg in list(expr.arguments.nodes)):
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if isinstance(a, LiteralValue):
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func_args.append(a.value)
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else:
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func_args.append(a)
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func = math_functions.get(funcname, builtin_functions.get(funcname))
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try:
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return LiteralValue(value=func(*func_args), sourceref=expr.arguments.sourceref) # type: ignore
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except Exception as x:
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raise ExpressionEvaluationError(str(x), expr.sourceref)
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else:
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raise ExpressionEvaluationError("can only use math- or builtin function", expr.sourceref)
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elif isinstance(expr.target, Dereference): # '[...](1,2,3)'
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raise ExpressionEvaluationError("dereferenced value call is not a constant value", expr.sourceref)
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elif isinstance(expr.target, LiteralValue) and type(expr.target.value) is int: # '64738()'
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raise ExpressionEvaluationError("immediate address call is not a constant value", expr.sourceref)
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else:
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raise NotImplementedError("weird call target", expr.target)
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elif isinstance(expr, ExpressionWithOperator):
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if expr.unary:
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left_sourceref = expr.left.sourceref if isinstance(expr.left, AstNode) else sourceref
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expr.left = self._process_constant_expression(expr.left, left_sourceref)
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expr.left.parent = expr
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if isinstance(expr.left, LiteralValue) and type(expr.left.value) in (int, float):
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try:
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if expr.operator == '-':
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return LiteralValue(value=-expr.left.value, sourceref=expr.left.sourceref) # type: ignore
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elif expr.operator == '~':
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return LiteralValue(value=~expr.left.value, sourceref=expr.left.sourceref) # type: ignore
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elif expr.operator in ("++", "--"):
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raise ValueError("incr/decr should not be an expression")
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raise ValueError("invalid unary operator", expr.operator)
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except TypeError as x:
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raise ParseError(str(x), expr.sourceref) from None
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raise ValueError("invalid operand type for unary operator", expr.left, expr.operator)
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else:
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left_sourceref = expr.left.sourceref if isinstance(expr.left, AstNode) else sourceref
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expr.left = self._process_constant_expression(expr.left, left_sourceref)
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expr.left.parent = expr
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right_sourceref = expr.right.sourceref if isinstance(expr.right, AstNode) else sourceref
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expr.right = self._process_constant_expression(expr.right, right_sourceref)
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expr.right.parent = expr
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if isinstance(expr.left, LiteralValue):
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if isinstance(expr.right, LiteralValue):
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return expr.evaluate_primitive_constants(expr.right.sourceref)
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else:
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raise ExpressionEvaluationError("constant literal value required on right, not {}"
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.format(expr.right.__class__.__name__), right_sourceref)
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else:
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raise ExpressionEvaluationError("constant literal value required on left, not {}"
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.format(expr.left.__class__.__name__), left_sourceref)
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else:
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raise ExpressionEvaluationError("constant value required, not {}".format(expr.__class__.__name__), expr.sourceref)
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def _process_dynamic_expression(self, expr: Expression, sourceref: SourceRef) -> Expression:
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# constant-fold a dynamic expression
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if isinstance(expr, LiteralValue):
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return expr
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try:
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return LiteralValue(value=expr.const_value(), sourceref=sourceref) # type: ignore
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except NotCompiletimeConstantError:
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pass
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if isinstance(expr, SymbolName):
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try:
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return self._process_constant_expression(expr, sourceref)
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except (ExpressionEvaluationError, NotCompiletimeConstantError):
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return expr
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elif isinstance(expr, AddressOf):
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try:
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return self._process_constant_expression(expr, sourceref)
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except (ExpressionEvaluationError, NotCompiletimeConstantError):
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return expr
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elif isinstance(expr, SubCall):
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try:
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return self._process_constant_expression(expr, sourceref)
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except (ExpressionEvaluationError, NotCompiletimeConstantError):
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if isinstance(expr.target, SymbolName):
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check_symbol_definition(expr.target.name, expr.my_scope(), expr.target.sourceref)
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return expr
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elif isinstance(expr, (Register, Dereference)):
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return expr
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elif isinstance(expr, ExpressionWithOperator):
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if expr.unary:
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left_sourceref = expr.left.sourceref if isinstance(expr.left, AstNode) else sourceref
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expr.left = self._process_dynamic_expression(expr.left, left_sourceref)
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expr.left.parent = expr
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try:
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return self._process_constant_expression(expr, sourceref)
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except (ExpressionEvaluationError, NotCompiletimeConstantError):
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return expr
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else:
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left_sourceref = expr.left.sourceref if isinstance(expr.left, AstNode) else sourceref
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expr.left = self._process_dynamic_expression(expr.left, left_sourceref)
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expr.left.parent = expr
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right_sourceref = expr.right.sourceref if isinstance(expr.right, AstNode) else sourceref
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expr.right = self._process_dynamic_expression(expr.right, right_sourceref)
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expr.right.parent = expr
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try:
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return self._process_constant_expression(expr, sourceref)
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except (ExpressionEvaluationError, NotCompiletimeConstantError):
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return expr
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else:
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raise ParseError("expression required, not {}".format(expr.__class__.__name__), expr.sourceref)
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