icode: new IEscapeMark class to bind ISeq and IEscape

[nit.git] / src / icode / icode_base.nit

# This file is part of NIT ( http://www.nitlanguage.org ).
#
# Copyright 2009 Jean Privat <jean@pryen.org>
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
#     http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.

# Base classes for Nit intermediate code representation
package icode_base

import metamodel
import mmloader

## UTILITY CLASSES ##

# Register store local variable and intermediate results
class IRegister
        # The static type
        readable var _stype: MMType
        init(s: MMType)
        do
                _stype = s
        end
end

# A mark used to associate IEscapes to ISeqs
class IEscapeMark
end

# A Closure declaration
class IClosureDecl
        # The associated closure definition
        readable var _closure: MMClosure

        # The default implementation
        readable writable var _default: nullable IRoutine

        init(c: MMClosure) do _closure = c
end

# A routine is a sequence of icodes with entry iregisters (params) and an exit iregister (result)
class IRoutine
        # The parameters of the routine
        readable var _params: Sequence[IRegister]

        # The closure declared
        readable writable var _closure_decls: nullable Sequence[IClosureDecl] = null

        # The local variables (excluding params and result)
        readable var _registers: Set[IRegister] = new ArraySet[IRegister]

        # The result of the routine
        readable var _result: nullable IRegister

        # The local escapes marks of the routine
        readable var _escape_marks: Set[IEscapeMark] = new ArraySet[IEscapeMark]

        # The sequence of icode
        readable var _body: ISeq = new ISeq

        # The location of the iroutine (if any)
        readable writable var _location: nullable Location = null

        init(p: Sequence[IRegister], r: nullable IRegister)
        do
                _params = p.to_a
                _result = r
        end
end

# A closure definition in a iroutine body
class IClosureDef
special IRoutine
        init(p: Array[IRegister], r: nullable IRegister)
        do
                super(p, r)
        end
end

## INTERMEDIATE CODE ##

# The root of the intermediate code representation
abstract class ICode
        # The number of registers used by the icode
        fun arity: Int is abstract

        # The result of the icode (if any)
        readable writable var _result: nullable IRegister = null

        # The location of the icode (if any)
        readable writable var _location: nullable Location = null

        # Is the icode side effect free?
        fun is_pure: Bool do return false
end

# An icode that uses no registers (no args)
abstract class ICode0
special ICode
        redef fun arity do return 0
end

# An icode that uses a single register (1 arg)
abstract class ICode1
special ICode
        redef fun arity do return 1

        # The single argument
        readable var _expr: IRegister

        init(e: IRegister) do _expr = e
end

# An icode that uses two single registers (2 args)
abstract class ICode2
special ICode
        redef fun arity do return 2

        # The first argument
        readable var _expr1: IRegister

        # The second argument
        readable var _expr2: IRegister

        init(e1, e2: IRegister)
        do
                _expr1 = e1
                _expr2 = e2
        end
end

# An icode that uses a variable number of registers (n args) and a variable number of closure definitions
abstract class ICodeN
special ICode
        redef fun arity do return _exprs.length

        # All arguments
        readable var _exprs: Sequence[IRegister]

        # All closure definition
        readable writable var _closure_defs: nullable Sequence[nullable IClosureDef]

        init(e: nullable Sequence[IRegister])
        do
                if e == null then
                        _exprs = new Array[IRegister]
                else
                        _exprs = e
                end
        end
end

#################################################

# A linear sequence of ICode
class ISeq
special ICode0
        # The sequence of icode
        readable var _icodes: List[ICode] = new List[ICode]

        # The associated iescape_mark (if any)
        readable writable var _iescape_mark: nullable IEscapeMark

        init do end
end

# An infinite loop of ICode
# Use IEscape to exit
class ILoop
special ISeq
        init do end
end

# A Condidianal if-then-else statement
# expr is the condition
class IIf
special ICode1
        # The 'then' sequence of icode
        readable var _then_seq: ISeq = new ISeq
        # The 'else' sequence of icode
        readable var _else_seq: ISeq = new ISeq
        init(e: IRegister) do super
end

# Escape to to end of a parent sequence
class IEscape
special ICode0
        # The seqeuence to escape
        # The control flow continues at the next icode after the associated sequence
        readable var _iescape_mark: IEscapeMark
        init(mark: IEscapeMark) do _iescape_mark = mark
end

# An abort statement
class IAbort
special ICode0
        # The reason the abort occured
        # tests.first is the format
        readable var _texts: Array[String]
        # The module that has the abort
        readable var _module_location: MMModule
        init(t: Array[String], ml: MMModule)
        do
                _texts = t
                _module_location = ml
        end
end

#################################################

# The root of all method invocations
abstract class IAbsCall
special ICodeN
        # The called method
        readable var _property: MMMethod

        init(p: MMMethod, e: Sequence[IRegister])
        do
                super(e)
                _property = p
        end
end

# A simple procedure or function call
# exprs.first is the reciever, other are arguments
class ICall
special IAbsCall
        init(p, e) do super
end

# A super method call
# exprs.first is the reciever, other are arguments
class ISuper
special IAbsCall
        init(p, e) do super
end

# An instantiation
# no reciever, all exprs are arguments
# Will call in order:
# - IAllocateInstance
# - IInitAttributes
# - IStaticCall -> target Initializer
# - ICheckInstance
class INew
special IAbsCall
        # The type to instantiate
        readable var _stype: MMType
        init(t: MMType, p: MMMethod, a: Sequence[IRegister])
        do
                super(p, a)
                _stype = t
        end
end

# An allocation of a new object
# No receivers, returns a new object of type 't'
# Will allocate memory and ensure dynamic type and object identity
class IAllocateInstance
special ICode0
        # The type to allocate
        readable var _stype: MMType
        init(t: MMType)
        do
                _stype = t
        end
end

# A static call to a specific method
class IStaticCall
special IAbsCall
        init(p: MMMethod, a: Sequence[IRegister]) do super
end

# A validation of a newly constructed instance
class ICheckInstance
special ICode1
        # The type to allocate
        readable var _stype: MMType
        init(t: MMType, e: IRegister)
        do
                super(e)
                _stype = t
        end
end

# Initialisation of default attributes of a new instance
class IInitAttributes
special ICode1
        # The type to initialize
        readable var _stype: MMType
        init(t: MMType, e: IRegister)
        do
                super(e)
                _stype = t
        end
end

# A closure call
# exprs are the arguments
class IClosCall
special ICodeN
        # The called closure
        readable var _closure_decl: IClosureDecl

        # The !break sequence (if any)
        readable writable var _break_seq: nullable ISeq = null

        init(c: IClosureDecl, e: Sequence[IRegister])
        do
                super(e)
                _closure_decl = c
        end
end

# A native C code
# Mainly used to implements things that do not have a specific ICode yet
# expr are the arguments
class INative
special ICodeN
        # The native C code
        # Special character sequence '@@@' will be substitued in order with the arguments
        readable var _code: String

        init(c: String, e: nullable Sequence[IRegister])
        do
                super(e)
                _code = c
        end

        redef readable writable var _is_pure: Bool = false
end

# A register assigment
# expr is the assigned value
# result is the register assigned
class IMove
special ICode1
        init(r: IRegister, e: IRegister)
        do
                super(e)
                _result = r
        end

        redef fun is_pure do return true
end

# An attribute read access
# expr is the reciever
class IAttrRead
special ICode1
        # The accessed attribute
        readable var _property: MMAttribute

        init(p: MMAttribute, r: IRegister)
        do
                super(r)
                _property = p
        end

        redef fun is_pure do return true
end

# An attribute assignment
# expr1 is the receiver, expr2 is the assigned value
class IAttrWrite
special ICode2
        # The accessed attribute
        readable var _property: MMAttribute

        init(p: MMAttribute, r: IRegister, v: IRegister)
        do
                super(r, v)
                _property = p
        end
end


# An attribute is_set check
# expr is the reciever
class IAttrIsset
special ICode1
        # The accessed attribute
        readable var _property: MMAttribute

        init(p: MMAttribute, r: IRegister)
        do
                super(r)
                _property = p
        end

        redef fun is_pure do return true
end

# A type check
# expr is the expression checked
class ITypeCheck
special ICode1
        # The static type checkes to
        readable var _stype: MMType

        init(e: IRegister, t: MMType)
        do
                super(e)
                _stype = t
        end

        redef fun is_pure do return true
end

# The 'is' operator
# expr1 and expr2 are both operands
class IIs
special ICode2
        init(e1, e2: IRegister)
        do
                super
        end

        redef fun is_pure do return true
end

# The unary 'not' operation
# expr is the operand
class INot
special ICode1
        init(e: IRegister)
        do
                super
        end

        redef fun is_pure do return true
end

# Evaluate body once them return the same value again and again
# if result is not null, then it must also be assigned in the body
class IOnce
special ICode0
        readable var _body: ISeq = new ISeq
        init do end
end

# Is a closure given as a parameter?
class IHasClos
special ICode0
        # The called closure
        readable var _closure_decl: IClosureDecl

        init(c: IClosureDecl)
        do
                _closure_decl = c
        end

        redef fun is_pure do return true
end

#################################################

redef class MMAttribute
        # The attached initialisation iroutine if any
        # To call between the allocate-instance and the initialize-instance
        fun iroutine: nullable IRoutine is abstract
end

redef class MMMethod
        # The attached body iroutine if any
        fun iroutine: nullable IRoutine is abstract
end