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from back.tac import *
from back.generator import Register
import sys
class Node(object):
labels = 0
def newlabel(self):
Node.labels += 1
return Node.labels
def emitlabel(self, i):
TACList().add(Label("L%d" % i))
def emit(self, op, arg1=None, arg2=None):
self.debug("emit(): op = %s, arg = %s, arg2 = %s" % (op, arg1, arg2))
TACList().add(TAC(op, arg1, arg2))
def debug(self, msg):
#sys.stdout.write("DEBUG: " + msg + "\n")
#sys.stdout.flush()
return
class Program(Node):
def __init__(self, functions, lineno = -1):
self.functions = functions
self.lineno = lineno
def generate(self):
self.debug("Program.generate(): %s" % repr(self))
self.emit(Op.JMP, "main")
for function in self.functions:
function.generate()
def __repr__(self):
return "<Program: %s>" % self.functions
class Function(Node):
def __init__(self, name, params, statement, lineno = -1):
self.name = name
self.params = params
self.statement = statement
self.lineno = lineno
def emit_prologue(self, name):
TACList().add(FunctionPrologue(name))
def emit_epilogue(self, name):
TACList().add(FunctionEpilogue(name))
def generate(self):
self.debug("Function.generate(): %s" % repr(self))
self.emit_prologue(self.name)
Register().set_function(self.name)
begin = self.newlabel()
after = self.newlabel()
self.emitlabel(begin)
self.statement.generate(begin, after, after)
self.emit(Op.RETURN, 0, after)
self.emitlabel(after)
self.emit_epilogue(self.name)
def __repr__(self):
return "<Function: %s(%s) at line %d: %s>" % (self.name, str(self.params), self.lineno, str(self.statement))
class Statement(Node):
pass
class Expression(Node):
pass
class Sequence(Statement):
def __init__(self, s1, s2, lineno = -1):
self.s1 = s1
self.s2 = s2
self.lineno = lineno
def generate(self, before, after, last):
self.debug("Sequence.generate(before = %d, after = %d): %s" % (before, after, repr(self)))
if not self.s1:
self.s2.generate(before, after, last)
elif not self.s2:
self.s1.generate(before, after, last)
else:
label = self.newlabel()
self.s1.generate(before, label, last)
self.emitlabel(label)
self.s2.generate(label, after, last)
def __repr__(self):
return "<Sequence at line %d: %s, %s>" % (self.lineno, self.s1, self.s2)
class IfStatement(Statement):
def __init__(self, expression, true_statement, false_statement, lineno = -1):
self.expression = expression
self.true_statement = true_statement
self.false_statement = false_statement
self.lineno = lineno
def generate(self, before, after, last):
self.debug("IfStatement.generate(before = %d, after = %d): %s" % (before, after, repr(self)))
x = self.expression.reduce()
if self.false_statement:
true_label = self.newlabel()
false_label = self.newlabel()
self.emit(Op.BEZ, x, "L%d" % false_label)
self.emitlabel(true_label)
self.true_statement.generate(true_label, after, last)
self.emit(Op.JMP, "L%d" % after)
self.emitlabel(false_label)
self.false_statement.generate(false_label, after, last)
else:
true_label = self.newlabel()
self.emit(Op.BEZ, x, "L%d" % after)
self.emitlabel(true_label)
self.true_statement.generate(true_label, after, last)
def __repr__(self):
return "<IfStatement at line %d>" % self.lineno
class WhileStatement(Statement):
def __init__(self, expression, statement, lineno = -1):
self.expression = expression
self.statement = statement
self.lineno = lineno
def generate(self, before, after, last):
self.debug("WhileStatement.generate(before = %d, after = %d): %s" % (before, after, repr(self)))
self.emit(Op.BEZ, self.expression.reduce(), "L%d" % after)
label = self.newlabel()
self.emitlabel(label)
self.statement.generate(label, before, last)
self.emit(Op.JMP, "L%d" % before)
def __repr__(self):
return "<WhileStatement at line %d>" % self.lineno
class ReturnStatement(Statement):
def __init__(self, expression, lineno = -1):
self.expression = expression
self.lineno = lineno
def generate(self, before, after, last):
self.debug("ReturnStatement.generate(before = %d, after = %d): %s" % (before, after, repr(self)))
self.emit(Op.RETURN, self.expression.reduce(), last)
def __repr__(self):
return "<ReturnStatement at line %d>" % self.lineno
class PrintStatement(Statement):
def __init__(self, expression, lineno = -1):
self.expression = expression
self.lineno = lineno
def generate(self, before, after, last):
self.debug("PrintStatement.generate(before = %d, after = %d): %s" % (before, after, repr(self)))
self.emit(Op.PRINT, self.expression.reduce(), last)
def __repr__(self):
return "<PrintStatement at line %d>" % self.lineno
class AssignStatement(Statement):
def __init__(self, ident, expression, lineno = -1):
self.ident = ident
self.expression = expression
self.lineno = lineno
def generate(self, before, after, last):
self.debug("AssignStatement.generate(before = %d, after = %d): %s" % (before, after, repr(self)))
self.emit(Op.STORE, self.ident, self.expression.reduce())
def __repr__(self):
return "<AssignStatement for %s at line %d>" % (self.ident, self.lineno)
class FunctionCall(Statement, Expression):
def __init__(self, ident, arguments = [], lineno = -1):
self.ident = ident
self.arguments = arguments
self.lineno = lineno
def push_params(self):
self.arguments.reverse()
for argument in self.arguments:
self.emit(Op.PUSH, argument.reduce())
self.arguments.reverse()
def pop_params(self):
for argument in self.arguments:
self.emit(Op.POP, 0)
def generate(self, before, after, last):
self.debug("FunctionCall.generate(): %s" % (repr(self)))
self.push_params()
self.emit(Op.CALL, self.ident, 0)
self.pop_params()
def reduce(self):
self.debug("FunctionCall.reduce(): %s" % repr(self))
self.push_params()
r = Register().new()
self.emit(Op.CALL, self.ident, r)
self.pop_params()
return r
def __repr__(self):
return "<FunctionCall for %s(%s) at line %d>" % (self.ident, self.arguments, self.lineno)
class Operation(Expression):
def __init__(self, op, lineno = -1):
self.op = op
self.lineno = -1
def __repr__(self):
return "<Operation at line %d>" % self.lineno
class UnaryExpression(Operation):
""" Unary expressions are !x or -x ..."""
def __init__(self, op, right, lineno = -1):
super(UnaryExpression, self).__init__(op, lineno)
self.right = right
def reduce(self):
self.debug("UnaryExpression.generate(): %s" % repr(self))
op = {
"!": Op.NOT,
"-": Op.MINUS,
}[self.op]
r = self.right.reduce()
self.emit(op, r)
return r
def __repr__(self):
return "<UnaryExpression: %s(%s) at line %d>" % (self.op, self.right, self.lineno)
class BinaryExpression(Operation):
""" Biary expression are x+y, x-y, ... """
def __init__(self, left, op, right, lineno = -1):
super(BinaryExpression, self).__init__(op, lineno)
self.left = left
self.right = right
def reduce(self):
self.debug("BinaryExpression.reduce(): %s" % repr(self))
arith_op = {
"+": Op.ADD,
"-": Op.SUB,
"*": Op.MUL,
"/": Op.DIV,
"%": Op.MOD,
}
logic_op = {
"==": Op.EQ,
"!=": Op.NE,
"<": Op.LT,
"<=": Op.LE,
">=": Op.GE,
">": Op.GT,
}
try:
op = arith_op[self.op]
r = self.left.reduce()
self.emit(op, r, self.right.reduce())
except KeyError:
op = logic_op[self.op]
r = Register().new()
self.emit(Op.CMP, self.left.reduce(), self.right.reduce())
self.emit(op, r)
return r
def __repr__(self):
return "<BinaryExpression: %s(%s, %s) at line %d>" % (self.op, self.left, self.right, self.lineno)
class Variable(Expression):
def __init__(self, name, lineno = -1):
self.name = name
self.lineno = lineno
def reduce(self):
self.debug("Variable.reduce(): %s" % repr(self))
r = Register().new()
self.emit(Op.LOAD, self.name, r)
return r
def __repr__(self):
return "<Variable: %s at line %d>" %(self.name, self.lineno)
class Constant(Expression):
def __init__(self, value, lineno = -1):
self.value = value
self.lineno = lineno
def reduce(self):
self.debug("Constant.reduce(): %s" % repr(self))
r = Register().new()
self.emit(Op.MOV, r, self.value)
return r
def __repr__(self):
return "<Constant: %d at line %d>" %(self.value, self.lineno)
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