"

 COPYRIGHT (c) 1994 by Claus Gittinger

	      All Rights Reserved

 This software is furnished under a license and may be used

 only in accordance with the terms of that license and with the

 inclusion of the above copyright notice.   This software may not

 be provided or otherwise made available to, or used by, any

 other person.  No title to or ownership of the software is

 hereby transferred.

"

Object subclass:#ExecutableFunction

	instanceVariableNames:'code*'

	classVariableNames:'ExecutionErrorSignal InvalidCodeSignal'

	poolDictionaries:''

	category:'Kernel-Methods'

!

!ExecutableFunction class methodsFor:'documentation'!

copyright

"

 COPYRIGHT (c) 1994 by Claus Gittinger

	      All Rights Reserved

 This software is furnished under a license and may be used

 only in accordance with the terms of that license and with the

 inclusion of the above copyright notice.   This software may not

 be provided or otherwise made available to, or used by, any

 other person.  No title to or ownership of the software is

 hereby transferred.

"

!

documentation

"

    This is an abstract class, to merge common attributes of all kinds of

    executable code objects; i.e. non-ST functions, Blocks and Methods

    and whatever there might be in the future.

    Instances of ExecutableCode are not meant to be created by user code -

    the compilers create instances of Method & Block, while compiling.

    (the VM would not even know what to do with such an instance, and triggered

     and exception, if ever encountered during block/method execution).

    NOTICE: layout known by runtime system and compiler - do not change

    [Instance variables:]

      code        <not_an_object>   the function pointer to the machine code.

                                    Not accessable from smalltalk code.

                                    (notice the '*' in the instVarNames definition)

    [Class variables:]

      ExecutionErrorSignal          parent of all execution errors

                                    (not raised itself)

      InvalidCodeSignal             codeObject is not executable

    [author:]

        Claus Gittinger

"

! !

!ExecutableFunction class methodsFor:'initialization'!

initialize

    "create signals raised by various errors"

    InvalidCodeSignal isNil ifTrue:[

        ExecutionErrorSignal := ErrorSignal newSignalMayProceed:true.

        ExecutionErrorSignal nameClass:self message:#executionErrorSignal.

        ExecutionErrorSignal notifierString:'execution error'.

        InvalidCodeSignal := ExecutionErrorSignal newSignalMayProceed:true.

        InvalidCodeSignal nameClass:self message:#invalidCodeSignal.

        InvalidCodeSignal notifierString:'invalid code-object - not executable'.

    ]

    "Modified: 22.4.1996 / 16:34:13 / cg"

! !

!ExecutableFunction class methodsFor:'Signal constants'!

executionErrorSignal

    "return the parent-signal of all execution errors"

    ^ ExecutionErrorSignal

! !

!ExecutableFunction class methodsFor:'queries'!

isBuiltInClass

    "return true if this class is known by the run-time-system.

     Here, true is returned for myself, false for subclasses."

    ^ self == ExecutableFunction

    "Modified: 23.1.1997 / 13:47:58 / cg"

! !

!ExecutableFunction methodsFor:'accessing'!

code

    "return the code field. This is not an object but the address of the machine instructions. 

     Therefore an integer representing the code-address is returned"

%{  /* NOCONTEXT */

    unsigned addr;

    if (__INST(code_) != nil) {

	addr = (int)__INST(code_);

	if (addr <= _MAX_INT) {

	    RETURN ( __MKSMALLINT(addr) );

	}

	RETURN ( __MKUINT(addr));

    }

%}.

    ^ nil

!

instVarAt:index

    "have to catch instVar access to code - since its no object"

    (index == 1) ifTrue:[^ self code].

    ^ super instVarAt:index

!

instVarAt:index put:value

    "have to catch instVar access to code - since its no object"

    (index == 1) ifTrue:[^ self code:value].

    ^ super instVarAt:index put:value

! !

!ExecutableFunction methodsFor:'binary storage'!

readBinaryContentsFrom: stream manager: manager

    "make certain, that no invalid function addresses are created."

    super readBinaryContentsFrom: stream manager: manager.

    self code:nil.

! !

!ExecutableFunction methodsFor:'error handling'!

invalidCode

    "{ Pragma: +optSpace }"

    "this error is triggered by the interpreter when something is wrong

     with the code object (any error not handled by Method-signals).

     In this case, the VM sends this to the bad method/block (the receiver).

     Can only happen when the Compiler/runtime system is broken or

     someone played around."

    ^ InvalidCodeSignal raise.

    "Modified: 4.11.1996 / 22:47:21 / cg"

! !

!ExecutableFunction methodsFor:'printing & storing'!

printOn:aStream

    "append a printed representation of the receiver to aStream"

    |addr|

    addr := self code.

    addr isNil ifTrue:[^ super printOn:aStream].

    aStream nextPutAll:self class name; nextPutAll:'(address: 0x';

            nextPutAll:(addr printStringRadix:16); nextPutAll:')'

    "Modified: 22.4.1996 / 16:36:05 / cg"

!

printStringForBrowserWithSelector:selector

    "return a printString to represent myself to the user in a browser."

    ^ selector

    "Modified: 22.4.1996 / 16:36:18 / cg"

! !

!ExecutableFunction methodsFor:'private accessing'!

code:anAddress

    "set the code field - DANGER ALERT. 

     This is not an object but the address of the machine instructions.

     Therefore the argument must be an integer representing this address.

     You can crash Smalltalk very badly when playing around here ...

     This method is for compiler support and very special cases (debugging) only

     - do not use"

%{  /* NOCONTEXT */

    if (__isSmallInteger(anAddress))

	__INST(code_) = (OBJ)(__intVal(anAddress));

    else {

	__INST(code_) = (OBJ)(__longIntVal(anAddress));

    }

%}

! !

!ExecutableFunction methodsFor:'queries'!

category

    "return the category of this codeObject.

     Return nil here, to alow alien codeObjects to be handled by the

     browsers."

    ^ nil

    "Created: 16.4.1996 / 16:31:15 / cg"

!

isExecutable

    "return true, if this codeObject is executable."

    self isInvalid ifTrue:[^ false].

    ^ self code notNil

    "Created: 16.4.1996 / 20:13:32 / cg"

!

isInvalid

    "return true, if this codeObject is invalidated.

     Return false here, to alow alien codeObjects to be handled by the

     browsers."

    ^ false

    "Created: 16.4.1996 / 16:31:42 / cg"

!

isLazyMethod

    "return true, if this is a lazy method.

     False is returned here - this method is redefined in LazyMethod"

    ^ false

    "Created: 16.4.1996 / 16:32:11 / cg"

    "Modified: 16.4.1996 / 16:32:36 / cg"

!

isUnloaded

    "return true, if the objects machine code has been unloaded

     from the system (i.e. it is not executable)."

    ^ self code isNil

    "Created: 16.4.1996 / 20:15:52 / cg"

!

isWrapped

    "return true, if this is a wrapper method.

     False is returned here - this method is redefined in WrappedMethod"

    ^ false

    "Created: 16.4.1996 / 16:33:24 / cg"

!

privacy

    "return a symbol describing the methods access rights (privacy);

     Currently, this is one of #private, #protected, #public or #ignored.

     Here we unconditionally return #public, to allow alien code objects

     to be handled by the browsers."

    ^ #public

    "Created: 16.4.1996 / 16:35:18 / cg"

!

referencesGlobal:aGlobalSymbol

    "return true, if this method references the global

     bound to aGlobalSymbol.

     Return false (we dont know) here, to allow alien code objects to be

     handled by the browsers."

     ^ false

    "Created: 16.4.1996 / 16:37:48 / cg"

!

sends:aSelectorSymbol

    "return true, if this method contains a message-send

     with aSelectorSymbol as selector. 

     - due to the simple check in the literal array, also simple uses 

       of aSelectorSymbol as symbol will return true.

       Should ask compiler, if there is really a send."

    ^ self referencesGlobal:aSelectorSymbol

    "Created: 16.4.1996 / 16:35:53 / cg"

! !

!ExecutableFunction class methodsFor:'documentation'!

version

! !

ExecutableFunction initialize!