# IR-Structures:


def dumpgv(m, outf):
    print('digraph G ', file=outf)
    print('{', file=outf)
    for f in m.Functions:
     print('{} [label="{}" shape=box3d]'.format(id(f), f),file=outf)
     for bb in f.Blocks:
        contents = str(bb) + '\n'
        contents += '\n'.join([str(i) for i in bb.Instructions])
        outf.write('{0} [shape=note label="{1}"];\n'.format(id(bb), contents))
        for successor in bb.Successors:
           print('"{}" -> "{}"\n'.format(id(bb), id(successor)), file=outf)

     outf.write('"{}" -> "{}" [label="entry"]\n'.format(id(f), id(f.entry)))
    print('}', file=outf)


class Module:
    """ Main container of variables and functions. """
    def __init__(self, name):
      self.name = name
      self.funcs = []
      self.variables = []

    def __repr__(self):
        return 'IR-module [{0}]'.format(self.name)

    def addFunc(self, f):
        self.funcs.append(f)

    addFunction = addFunc

    def addVariable(self, v):
        self.variables.append(v)

    def getVariables(self):
        return self.variables

    Variables = property(getVariables)

    def getFunctions(self):
        return self.funcs

    Functions = property(getFunctions)

    def findFunction(self, name):
        for f in self.funcs:
            if f.name == name:
                return f
        raise KeyError(name)

    getFunction = findFunction

    def dump(self):
        print(self)
        indent = '   '
        for v in self.Variables:
            print(indent, v)
        for fn in self.Functions:
            print(fn)
            for bb in fn.Blocks:
                print(indent+str(bb))
                for ins in bb.Instructions:
                    print(indent * 2 + str(ins))

    # Analysis functions:
    def check(self):
        """ Perform sanity check on module """
        for f in self.Functions:
            f.check()


class Function:
    """
      Function definition. Contains an entry block.
    """
    def __init__(self, name):
        self.name = name
        self.entry = Block('{}_entry'.format(name))
        self.epiloog = Block('{}_epilog'.format(name))
        self.epiloog.addInstruction(Terminator())
        self.arguments = []

    def __repr__(self):
        args = ','.join(str(a) for a in self.arguments)
        return 'Function {}({})'.format(self.name, args)

    def addBB(self, bb):
        self.bbs.append(bb)
        bb.parent = self
    addBlock = addBB

    def removeBasicBlock(self, bb):
        self.bbs.remove(bb)
        bb.parent = None

    def getBBs(self):
        bbs = [self.entry]
        worklist = [self.entry]
        while worklist:
            b = worklist.pop()
            for sb in b.Successors:
                if sb not in bbs:
                    bbs.append(sb)
                    worklist.append(sb)
        bbs.remove(self.entry)
        if self.epiloog in bbs:
            bbs.remove(self.epiloog)
        bbs.insert(0, self.entry)
        bbs.append(self.epiloog)
        return bbs

    def findBasicBlock(self, name):
        for bb in self.bbs:
            if bb.name == name:
                return bb
        raise KeyError(name)

    Blocks = property(getBBs)

    @property
    def Entry(self):
        return self.entry

    def check(self):
        for b in self.Blocks:
            b.check()

    def addParameter(self, pname):
        self.arguments.append(pname)

    def call(self, *args):
        varmap = {}
        bb = self.Entry
        ip = 0
        while True:
            i = bb.Instructions[ip]
            ip += 1
            return


class Block:
    """ 
        Uninterrupted sequence of instructions with a label at the start.
    """
    def __init__(self, name):
        self.name = name
        self.instructions = []

    def __repr__(self):
        return 'Block {0}'.format(self.name)

    def addInstruction(self, i):
        i.parent = self
        assert not isinstance(self.LastInstruction, LastStatement)
        self.instructions.append(i)

    def replaceInstruction(self, i1, i2):
        idx = self.instructions.index(i1)
        i1.parent = None
        i1.delete()
        i2.parent = self
        self.instructions[idx] = i2

    def removeInstruction(self, i):
        i.parent = None
        i.delete()
        self.instructions.remove(i)

    def getInstructions(self):
        return self.instructions
    Instructions = property(getInstructions)

    def getLastIns(self):
        if not self.Empty:
            return self.instructions[-1]
    LastInstruction = property(getLastIns)

    @property
    def Empty(self):
        return len(self.instructions) == 0

    @property
    def FirstInstruction(self):
        return self.instructions[0]

    def getSuccessors(self):
        if not self.Empty:
            return self.LastInstruction.Targets
        return []
    Successors = property(getSuccessors)

    def getPredecessors(self):
        preds = []
        for bb in self.parent.BasicBlocks:
            if self in bb.Successors:
                preds.append(bb)
        return preds
    Predecessors = property(getPredecessors)

    def precedes(self, other):
        raise NotImplementedError()

    def check(self):
        assert isinstance(self.LastInstruction, LastStatement)
        for i in self.instructions[:-1]:
            assert not isinstance(i, LastStatement)


# Instructions:

class Expression:
    pass


class Const(Expression):
    def __init__(self, value):
        self.value = value

    def __repr__(self):
        return 'Constant {}'.format(self.value)


# Function calling:
class Call(Expression):
    def __init__(self, f, arguments):
        self.f = f
        assert type(f) is Function
        self.arguments = arguments

    def __repr__(self):
        args = ','.join([str(arg) for arg in self.arguments])
        return '{}({})'.format(self.f.name, args)


# Data operations
class Binop(Expression):
    ops = ['+', '-', '*', '/', '|', '&', '<<', '>>']
    def __init__(self, value1, operation, value2):
        assert operation in Binop.ops
        self.value1 = value1
        self.value2 = value2
        self.operation = operation

    def __repr__(self):
        a, b = self.value1, self.value2
        return '({} {} {})'.format(a, self.operation, b)


def Add(a, b):
    """ Convenience call """
    return Binop(a, '+', b)


class Alloc(Expression):
    """ Allocates space on the stack """
    def __init__(self):
        super().__init__()

    def __repr__(self):
        return 'Alloc'


class Variable(Expression):
    def __init__(self, name):
        self.name = name

    def __repr__(self):
        return 'Var {}'.format(self.name)


class LocalVariable(Variable):
    pass


class GlobalVariable(Variable):
    pass


class Parameter(Variable):
    def __repr__(self):
        return 'Param {}'.format(self.name)


class Temp(Expression):
    """ Temporary storage, same as register """
    def __init__(self, name):
        self.name = name

    def __repr__(self):
        return 'T_{}_'.format(self.name)


class Mem(Expression):
    def __init__(self, e):
        self.e = e

    def __repr__(self):
        return '[{}]'.format(self.e)


class Statement:
    """ Base class for all instructions. """
    pass


class Move(Statement):
    def __init__(self, dst, src):
        self.dst = dst
        self.src = src

    def __repr__(self):
        return '{} = {}'.format(self.dst, self.src)


class Exp(Statement):
    def __init__(self, e):
        self.e = e


class Label(Statement):
    def __init__(self, name):
        self.name = name
        self.statements = []

    def __repr__(self):
        return 'LABEL {}:'.format(self.name)


# Branching:
class LastStatement(Statement):
    pass


class Terminator(LastStatement):
    """ Instruction that terminates the terminal block """
    Targets = []
    def __repr__(self):
        return 'Terminator'


class Jump(LastStatement):
    def __init__(self, target):
        self.target = target
        self.Targets = [target]

    def __repr__(self):
        return 'BRANCH {}'.format(self.target.name)


class CJump(LastStatement):
    def __init__(self, a, cond, b, lab_yes, lab_no):
        assert cond in ['==', '<', '>', '>=', '<=', '!=']
        self.a = a
        self.cond = cond
        self.b = b
        self.lab_yes = lab_yes
        self.lab_no = lab_no
        self.Targets = [lab_yes, lab_no]

    def __repr__(self):
        return 'IF {} {} {} THEN {} ELSE {}'.format(self.a, self.cond, self.b, self.lab_yes, self.lab_no)