#flushCache with MethoWrappers in CogVM

Hi Eliot. I am implementing some kind of MethodWrappes/ObjectsAsMethod, whihc basically use the #run:with:in trick.
My question is that I am not sure how to implement #flushCache in my wrappers. This method is called by MethodDictionary>>#at:put:  when I want to put back the original CompiledMethod.

MyClass methodDict at: #foo put: MyWrapper withMethod: (MyClass>>#foo).
...
MyClass methodDict at: #foo put:  wrapper wrappedMethod
->  here it sends #flushCache to my wrapper instance.

In the StandardVM, I realised that at that moment, there is an entry in the cache that has selector: #foo, method:  my wrapped instance, class: MyClass, etc...

So, to flush this, I have to options:

MyWrappers>>flushCache
self wrappedMethod selector flushCache

or....

MyWrappers>>flushCache
  <primitive: 116>

this is because "self" will be found in the entry as "method" in the cache table...

So, first, are my assumptions correct?

Now, in cog I am not sure if both solutions are still valid. If I see CoInterpreterPrimitives>> primitiveFlushCacheByMethod

you do at the end:

(self methodHasCogMethod: oldMethod) ifTrue:
        [cogit unlinkSendsTo: (self cogMethodOf: oldMethod)]

and

methodHasCogMethod: aMethodOop
    <api>
    self assert: (objectMemory isNonIntegerObject: aMethodOop).
    ^self isCogMethodReference: (self rawHeaderOf: aMethodOop)


So, it is not safe if the method is something different than a compiled method.

Is that correct? should I flush the cache entering by selector instead?  which is the safe way to clean the cache in this case?

thanks

Mariano

 
Hi Mariano,

    VMMaker-oscog.52 is uploading:

primitiveFlushCacheByMethod

"The receiver is a compiledMethod.  Clear all entries in the method lookup cache that

refer to this method, presumably because it has been redefined, overridden or removed.

Override to flush appropriate machine code caches also."

| probe oldMethod primIdx |

oldMethod := self stackTop.

probe := 0.

1 to: MethodCacheEntries do:

[:i |

(methodCache at: probe + MethodCacheMethod) = oldMethod ifTrue:

[methodCache at: probe + MethodCacheSelector put: 0].

probe := probe + MethodCacheEntrySize].

(objectMemory isOopCompiledMethod: oldMethod) ifTrue:

[primIdx := self primitiveIndexOf: oldMethod.

primIdx = PrimitiveExternalCallIndex ifTrue:

["It's primitiveExternalCall"

self flushExternalPrimitiveOf: oldMethod].

(self methodHasCogMethod: oldMethod) ifTrue:

[cogit unlinkSendsTo: (self cogMethodOf: oldMethod)]]

On Wed, Mar 16, 2011 at 3:20 AM, Mariano Martinez Peck <[hidden email]> wrote:

 
Hi Eliot. I am implementing some kind of MethodWrappes/ObjectsAsMethod, whihc basically use the #run:with:in trick.
My question is that I am not sure how to implement #flushCache in my wrappers. This method is called by MethodDictionary>>#at:put:  when I want to put back the original CompiledMethod.

MyClass methodDict at: #foo put: MyWrapper withMethod: (MyClass>>#foo).
...
MyClass methodDict at: #foo put:  wrapper wrappedMethod
->  here it sends #flushCache to my wrapper instance.

In the StandardVM, I realised that at that moment, there is an entry in the cache that has selector: #foo, method:  my wrapped instance, class: MyClass, etc...

So, to flush this, I have to options:

MyWrappers>>flushCache
self wrappedMethod selector flushCache

or....

MyWrappers>>flushCache
  <primitive: 116>

this is because "self" will be found in the entry as "method" in the cache table...

So, first, are my assumptions correct?

Now, in cog I am not sure if both solutions are still valid. If I see CoInterpreterPrimitives>> primitiveFlushCacheByMethod

you do at the end:

(self methodHasCogMethod: oldMethod) ifTrue:
        [cogit unlinkSendsTo: (self cogMethodOf: oldMethod)]

and

methodHasCogMethod: aMethodOop
    <api>
    self assert: (objectMemory isNonIntegerObject: aMethodOop).
    ^self isCogMethodReference: (self rawHeaderOf: aMethodOop)


So, it is not safe if the method is something different than a compiled method.

Is that correct? should I flush the cache entering by selector instead?  which is the safe way to clean the cache in this case?

thanks

Mariano

Thanks Eliot. So I assume that the correcet way to implement #flushCache  in my object as method is this:

MyObjectAsMethod>>flushCache
  <primitive: 116>

thanks Eliot

Mariano

On Sun, Mar 20, 2011 at 5:32 PM, Eliot Miranda <[hidden email]> wrote:

 
Hi Mariano,

    VMMaker-oscog.52 is uploading:

primitiveFlushCacheByMethod

"The receiver is a compiledMethod.  Clear all entries in the method lookup cache that

refer to this method, presumably because it has been redefined, overridden or removed.

Override to flush appropriate machine code caches also."

| probe oldMethod primIdx |

oldMethod := self stackTop.

probe := 0.

1 to: MethodCacheEntries do:

[:i |

(methodCache at: probe + MethodCacheMethod) = oldMethod ifTrue:

[methodCache at: probe + MethodCacheSelector put: 0].

probe := probe + MethodCacheEntrySize].

(objectMemory isOopCompiledMethod: oldMethod) ifTrue:

[primIdx := self primitiveIndexOf: oldMethod.

primIdx = PrimitiveExternalCallIndex ifTrue:

["It's primitiveExternalCall"

self flushExternalPrimitiveOf: oldMethod].

(self methodHasCogMethod: oldMethod) ifTrue:

[cogit unlinkSendsTo: (self cogMethodOf: oldMethod)]]

On Wed, Mar 16, 2011 at 3:20 AM, Mariano Martinez Peck <[hidden email]> wrote:

 
Hi Eliot. I am implementing some kind of MethodWrappes/ObjectsAsMethod, whihc basically use the #run:with:in trick.
My question is that I am not sure how to implement #flushCache in my wrappers. This method is called by MethodDictionary>>#at:put:  when I want to put back the original CompiledMethod.

MyClass methodDict at: #foo put: MyWrapper withMethod: (MyClass>>#foo).
...
MyClass methodDict at: #foo put:  wrapper wrappedMethod
->  here it sends #flushCache to my wrapper instance.

In the StandardVM, I realised that at that moment, there is an entry in the cache that has selector: #foo, method:  my wrapped instance, class: MyClass, etc...

So, to flush this, I have to options:

MyWrappers>>flushCache
self wrappedMethod selector flushCache

or....

MyWrappers>>flushCache
  <primitive: 116>

this is because "self" will be found in the entry as "method" in the cache table...

So, first, are my assumptions correct?

Now, in cog I am not sure if both solutions are still valid. If I see CoInterpreterPrimitives>> primitiveFlushCacheByMethod

you do at the end:

(self methodHasCogMethod: oldMethod) ifTrue:
        [cogit unlinkSendsTo: (self cogMethodOf: oldMethod)]

and

methodHasCogMethod: aMethodOop
    <api>
    self assert: (objectMemory isNonIntegerObject: aMethodOop).
    ^self isCogMethodReference: (self rawHeaderOf: aMethodOop)


So, it is not safe if the method is something different than a compiled method.

Is that correct? should I flush the cache entering by selector instead?  which is the safe way to clean the cache in this case?

thanks

Mariano