How to copy a CompiledMethod?
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How to copy a CompiledMethod?
 
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Hi
I am trying to make a complete duplicate of a CompiledMethod. I started with CompiledMethod>>#copyWithTrailerBytes: but I think that this way still leaves some things to copy. It duplicates all the literals, but I think that it doesn't duplicate a Pragma if for example, the method has one. Is there a proper way to completely make deep copy of a CompiledMethod? I mean, without writing my own. If there is a way to do it, I don't want to duplicate it. Thanks in advance. Gabriel |
Re: How to copy a CompiledMethod?
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On 25 November 2010 20:44, Gabriel Hernán Barbuto <[hidden email]> wrote:
> Hi > > I am trying to make a complete duplicate of a CompiledMethod. I > started with CompiledMethod>>#copyWithTrailerBytes: but I think that > this way still leaves some things to copy. It duplicates all the > literals, but I think that it doesn't duplicate a Pragma if for > example, the method has one. > AFAIR, pragmas are stored as one of literals. So, it actually should also make a copy of pragmas. > Is there a proper way to completely make deep copy of a > CompiledMethod? I mean, without writing my own. If there is a way to > do it, I don't want to duplicate it. > if you tell more, why #copy is not enough for you. > Thanks in advance. > Gabriel > > -- Best regards, Igor Stasenko AKA sig. |
Re: How to copy a CompiledMethod?
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Hi Igor
Thanks for your response. I am quite a new to all this low level stuff. So please bear with me if I am missing something obvious. I need to make a deep copy of a method dictionary. I was using copy but CompiledMethod does not define copy, and so it inherits it from Object. Object's copy does a shallowCopy followed by a postCopy. None of these methods is defined by CompiledMethod. So if I use that I will only get a shallow copy of the CompiledMethod instead of a deep copy. For example, if I try the following code snippet: | source copy | source := Object methodDict at: #at:. copy := source copy. Transcript show: 'Equals: '; show: source = copy; cr. Transcript show: 'Same: '; show: source == copy; cr. Transcript show: 'Literal at: '; show: source numLiterals - 1; show: ' '. Transcript show: (source literalAt: source numLiterals - 1); cr. Transcript show: 'Same AdditionalMethodState: '; show: (source literalAt: source numLiterals - 1) == (copy literalAt: copy numLiterals -1); cr. I get the following results on Transcript: Equals: true Same: false Literal at: 8 an AdditionalMethodState Same AdditionalMethodState: true Here the literal in position 8, an AdditionalMethodState is not being duplicated. Of course, I selected number 8 because that is the one I am interested in, but any literal besides symbols will do. If I replace copy with veryDeepCopy in the snippet above I get the following results: Equals: true Same: true Literal at: 8 an AdditionalMethodState Same AdditionalMethodState: true which are odd since I would not expect them to be the same. With respect to Pragmas. Please, inspect Object>>#at: and you will see that there is no pragma in the literals. The pragma is referenced by the AdditionalMethodState literal. So I am still looking for the correct, if there is one, way to completely duplicate a CompiledMethod. Maybe I should take a look at veryDeepCopy and see why it gives the results it gives and not what I expect. Any ideas are welcome. Best regards Gabriel The problem was that I was still getting references from outside and I was wondering why. On Thu, Nov 25, 2010 at 10:14 PM, Igor Stasenko <[hidden email]> wrote: > On 25 November 2010 20:44, Gabriel Hernán Barbuto <[hidden email]> wrote: >> Hi >> >> I am trying to make a complete duplicate of a CompiledMethod. I >> started with CompiledMethod>>#copyWithTrailerBytes: but I think that >> this way still leaves some things to copy. It duplicates all the >> literals, but I think that it doesn't duplicate a Pragma if for >> example, the method has one. >> > AFAIR, pragmas are stored as one of literals. > So, it actually should also make a copy of pragmas. > >> Is there a proper way to completely make deep copy of a >> CompiledMethod? I mean, without writing my own. If there is a way to >> do it, I don't want to duplicate it. >> > if you tell more, why #copy is not enough for you. > >> Thanks in advance. >> Gabriel >> >> > > > > -- > Best regards, > Igor Stasenko AKA sig. > > |
Re: How to copy a CompiledMethod?
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In reply to this post by Igor Stasenko
May be you should try to define a postCopy method on compiledMethod.
Now I do not know if the system relies on assumption that copy = shallowcopy for compiledMethods. Did you check the senders of verydeepcopy? Stef On Nov 25, 2010, at 11:57 PM, Gabriel Hernán Barbuto wrote: > Hi Igor > > Thanks for your response. I am quite a new to all this low level > stuff. So please bear with me if I am missing something obvious. > > I need to make a deep copy of a method dictionary. I was using copy > but CompiledMethod does not define copy, and so it inherits it from > Object. Object's copy does a shallowCopy followed by a postCopy. None > of these methods is defined by CompiledMethod. So if I use that I will > only get a shallow copy of the CompiledMethod instead of a deep copy. > > For example, if I try the following code snippet: > > | source copy | > source := Object methodDict at: #at:. > copy := source copy. > Transcript show: 'Equals: '; show: source = copy; cr. > Transcript show: 'Same: '; show: source == copy; cr. > Transcript show: 'Literal at: '; show: source numLiterals - 1; show: ' '. > Transcript show: (source literalAt: source numLiterals - 1); cr. > Transcript show: 'Same AdditionalMethodState: '; > show: (source literalAt: source numLiterals - 1) == (copy literalAt: > copy numLiterals -1); cr. > > I get the following results on Transcript: > > Equals: true > Same: false > Literal at: 8 an AdditionalMethodState > Same AdditionalMethodState: true > > Here the literal in position 8, an AdditionalMethodState is not being > duplicated. Of course, I selected number 8 because that is the one I > am interested in, but any literal besides symbols will do. > > If I replace copy with veryDeepCopy in the snippet above I get the > following results: > > Equals: true > Same: true > Literal at: 8 an AdditionalMethodState > Same AdditionalMethodState: true > > which are odd since I would not expect them to be the same. > > With respect to Pragmas. Please, inspect Object>>#at: and you will see > that there is no pragma in the literals. The pragma is referenced by > the AdditionalMethodState literal. > > So I am still looking for the correct, if there is one, way to > completely duplicate a CompiledMethod. Maybe I should take a look at > veryDeepCopy and see why it gives the results it gives and not what I > expect. > > Any ideas are welcome. > > Best regards > Gabriel > > The problem was that I was still getting references from outside and > I was wondering why. > > On Thu, Nov 25, 2010 at 10:14 PM, Igor Stasenko <[hidden email]> wrote: >> On 25 November 2010 20:44, Gabriel Hernán Barbuto <[hidden email]> wrote: >>> Hi >>> >>> I am trying to make a complete duplicate of a CompiledMethod. I >>> started with CompiledMethod>>#copyWithTrailerBytes: but I think that >>> this way still leaves some things to copy. It duplicates all the >>> literals, but I think that it doesn't duplicate a Pragma if for >>> example, the method has one. >>> >> AFAIR, pragmas are stored as one of literals. >> So, it actually should also make a copy of pragmas. >> >>> Is there a proper way to completely make deep copy of a >>> CompiledMethod? I mean, without writing my own. If there is a way to >>> do it, I don't want to duplicate it. >>> >> if you tell more, why #copy is not enough for you. >> >>> Thanks in advance. >>> Gabriel >>> >>> >> >> >> >> -- >> Best regards, >> Igor Stasenko AKA sig. >> >> > |
Re: How to copy a CompiledMethod?
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No. I did something even more simpler. I looked at CompiledMethod's
veryDeepCopy and that explains the behavior. The comment states: "Return self. I am always shared. Do not record me. Only use this for blocks. Normally methodDictionaries should not be copied this way." So, I wonder in which way should method dictionaries be copied. Bests Gabriel On Fri, Nov 26, 2010 at 10:09 AM, Stéphane Ducasse <[hidden email]> wrote: > May be you should try to define a postCopy method on compiledMethod. > Now I do not know if the system relies on assumption that copy = shallowcopy for compiledMethods. > > Did you check the senders of verydeepcopy? > > Stef > On Nov 25, 2010, at 11:57 PM, Gabriel Hernán Barbuto wrote: > >> Hi Igor >> >> Thanks for your response. I am quite a new to all this low level >> stuff. So please bear with me if I am missing something obvious. >> >> I need to make a deep copy of a method dictionary. I was using copy >> but CompiledMethod does not define copy, and so it inherits it from >> Object. Object's copy does a shallowCopy followed by a postCopy. None >> of these methods is defined by CompiledMethod. So if I use that I will >> only get a shallow copy of the CompiledMethod instead of a deep copy. >> >> For example, if I try the following code snippet: >> >> | source copy | >> source := Object methodDict at: #at:. >> copy := source copy. >> Transcript show: 'Equals: '; show: source = copy; cr. >> Transcript show: 'Same: '; show: source == copy; cr. >> Transcript show: 'Literal at: '; show: source numLiterals - 1; show: ' '. >> Transcript show: (source literalAt: source numLiterals - 1); cr. >> Transcript show: 'Same AdditionalMethodState: '; >> show: (source literalAt: source numLiterals - 1) == (copy literalAt: >> copy numLiterals -1); cr. >> >> I get the following results on Transcript: >> >> Equals: true >> Same: false >> Literal at: 8 an AdditionalMethodState >> Same AdditionalMethodState: true >> >> Here the literal in position 8, an AdditionalMethodState is not being >> duplicated. Of course, I selected number 8 because that is the one I >> am interested in, but any literal besides symbols will do. >> >> If I replace copy with veryDeepCopy in the snippet above I get the >> following results: >> >> Equals: true >> Same: true >> Literal at: 8 an AdditionalMethodState >> Same AdditionalMethodState: true >> >> which are odd since I would not expect them to be the same. >> >> With respect to Pragmas. Please, inspect Object>>#at: and you will see >> that there is no pragma in the literals. The pragma is referenced by >> the AdditionalMethodState literal. >> >> So I am still looking for the correct, if there is one, way to >> completely duplicate a CompiledMethod. Maybe I should take a look at >> veryDeepCopy and see why it gives the results it gives and not what I >> expect. >> >> Any ideas are welcome. >> >> Best regards >> Gabriel >> >> The problem was that I was still getting references from outside and >> I was wondering why. >> >> On Thu, Nov 25, 2010 at 10:14 PM, Igor Stasenko <[hidden email]> wrote: >>> On 25 November 2010 20:44, Gabriel Hernán Barbuto <[hidden email]> wrote: >>>> Hi >>>> >>>> I am trying to make a complete duplicate of a CompiledMethod. I >>>> started with CompiledMethod>>#copyWithTrailerBytes: but I think that >>>> this way still leaves some things to copy. It duplicates all the >>>> literals, but I think that it doesn't duplicate a Pragma if for >>>> example, the method has one. >>>> >>> AFAIR, pragmas are stored as one of literals. >>> So, it actually should also make a copy of pragmas. >>> >>>> Is there a proper way to completely make deep copy of a >>>> CompiledMethod? I mean, without writing my own. If there is a way to >>>> do it, I don't want to duplicate it. >>>> >>> if you tell more, why #copy is not enough for you. >>> >>>> Thanks in advance. >>>> Gabriel >>>> >>>> >>> >>> >>> >>> -- >>> Best regards, >>> Igor Stasenko AKA sig. >>> >>> >> > > > |
Re: How to copy a CompiledMethod?
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In reply to this post by Igor Stasenko
On Thu, Nov 25, 2010 at 1:14 PM, Igor Stasenko <[hidden email]> wrote:
Yes. pragmas are effectively referenced from literals. If a method needs ti the penultimate literal (which otherwise is the method;s selector) holds an AdditionalMethodState which refers back to its method. This needs to be copied if one is copying a method, since the backpointer needs to refer to the owning method, not the method form which the copy was made.
If literals are read-only (and Array/ByteArray/String/Float literals are conceptually read-only but not actually) you don't need to make a deep copy. You only need to copy the AdditionalMethodState, if present, and the class association, if you want to install the method somewhere else.
best Eliot
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Re: How to copy a CompiledMethod?
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Eliot
Thanks for your response. On Fri, Nov 26, 2010 at 5:49 PM, Eliot Miranda <[hidden email]> wrote: > > > On Thu, Nov 25, 2010 at 1:14 PM, Igor Stasenko <[hidden email]> wrote: >> >> On 25 November 2010 20:44, Gabriel Hernán Barbuto <[hidden email]> >> wrote: >> > Hi >> > >> > I am trying to make a complete duplicate of a CompiledMethod. I >> > started with CompiledMethod>>#copyWithTrailerBytes: but I think that >> > this way still leaves some things to copy. It duplicates all the >> > literals, but I think that it doesn't duplicate a Pragma if for >> > example, the method has one. >> > >> AFAIR, pragmas are stored as one of literals. >> So, it actually should also make a copy of pragmas. > > Yes. pragmas are effectively referenced from literals. If a method needs ti > the penultimate literal (which otherwise is the method;s selector) holds an > AdditionalMethodState which refers back to its method. This needs to be > copied if one is copying a method, since the backpointer needs to refer to > the owning method, not the method form which the copy was made. >> >> > Is there a proper way to completely make deep copy of a >> > CompiledMethod? I mean, without writing my own. If there is a way to >> > do it, I don't want to duplicate it. >> > >> if you tell more, why #copy is not enough for you. > > If literals are read-only (and Array/ByteArray/String/Float literals are > conceptually read-only but not actually) you don't need to make a deep copy. > You only need to copy the AdditionalMethodState, if present, and the class > association, if you want to install the method somewhere else. Yes that was exactly what I did. I handle both Association and AdditionalMethodState in a special way and just send copy to all the other literals. I was not sure what I could encounter in the literals so I opted to send copy to them. Maybe they will just return themselves or make an unnecessary duplicate. I have also taken care of copying the Pragmas referenced from any AdditionalMethodState. Igor mentioned that there could be Pragmas directly on the literals but I am not sure about that. I will have to get all the CompiledMethods and check if anyone has a Pragma among its literals, but that is not enough, maybe my image doesn't have any. I understand that all the literals are conceptually read only, and that copying anything besides the Associations, AdditionalMethodStates and Pragmas can waste memory and CPU cycles, but I am not interested in speed nor memory consumption right now. But I will take a note, in case some day I need to improve the copy. After copying all the Associations, AdditionalMethodStates and Pragmas that I've found I fix the references of both AdditionalMethodStates and Pragmas to the new method in order to break all references to objects in the current image that I don't want to show up in the new image. Thanks again. Best Gabriel > best > Eliot >> >> > Thanks in advance. >> > Gabriel >> > >> > >> >> >> >> -- >> Best regards, >> Igor Stasenko AKA sig. >> > > |
Re: How to copy a CompiledMethod?
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In reply to this post by Eliot Miranda-2
gabriel
veryDeepCopy should be replaced by copy and postCopy. So could you publish a version of postCopy with a couple of tests? Because this would be good to make progress from this side. Stef On Nov 26, 2010, at 6:14 PM, Gabriel Hernán Barbuto wrote: > Eliot > > Thanks for your response. > > On Fri, Nov 26, 2010 at 5:49 PM, Eliot Miranda <[hidden email]> wrote: >> >> >> On Thu, Nov 25, 2010 at 1:14 PM, Igor Stasenko <[hidden email]> wrote: >>> >>> On 25 November 2010 20:44, Gabriel Hernán Barbuto <[hidden email]> >>> wrote: >>>> Hi >>>> >>>> I am trying to make a complete duplicate of a CompiledMethod. I >>>> started with CompiledMethod>>#copyWithTrailerBytes: but I think that >>>> this way still leaves some things to copy. It duplicates all the >>>> literals, but I think that it doesn't duplicate a Pragma if for >>>> example, the method has one. >>>> >>> AFAIR, pragmas are stored as one of literals. >>> So, it actually should also make a copy of pragmas. >> >> Yes. pragmas are effectively referenced from literals. If a method needs ti >> the penultimate literal (which otherwise is the method;s selector) holds an >> AdditionalMethodState which refers back to its method. This needs to be >> copied if one is copying a method, since the backpointer needs to refer to >> the owning method, not the method form which the copy was made. >>> >>>> Is there a proper way to completely make deep copy of a >>>> CompiledMethod? I mean, without writing my own. If there is a way to >>>> do it, I don't want to duplicate it. >>>> >>> if you tell more, why #copy is not enough for you. >> >> If literals are read-only (and Array/ByteArray/String/Float literals are >> conceptually read-only but not actually) you don't need to make a deep copy. >> You only need to copy the AdditionalMethodState, if present, and the class >> association, if you want to install the method somewhere else. > > Yes that was exactly what I did. I handle both Association and > AdditionalMethodState in a special way and just send copy to all the > other literals. I was not sure what I could encounter in the literals > so I opted to send copy to them. Maybe they will just return > themselves or make an unnecessary duplicate. > > I have also taken care of copying the Pragmas referenced from any > AdditionalMethodState. Igor mentioned that there could be Pragmas > directly on the literals but I am not sure about that. I will have to > get all the CompiledMethods and check if anyone has a Pragma among its > literals, but that is not enough, maybe my image doesn't have any. > > I understand that all the literals are conceptually read only, and > that copying anything besides the Associations, AdditionalMethodStates > and Pragmas can waste memory and CPU cycles, but I am not interested > in speed nor memory consumption right now. But I will take a note, in > case some day I need to improve the copy. > > After copying all the Associations, AdditionalMethodStates and Pragmas > that I've found I fix the references of both AdditionalMethodStates > and Pragmas to the new method in order to break all references to > objects in the current image that I don't want to show up in the new > image. > > Thanks again. > > Best > Gabriel > >> best >> Eliot >>> >>>> Thanks in advance. >>>> Gabriel >>>> >>>> >>> >>> >>> >>> -- >>> Best regards, >>> Igor Stasenko AKA sig. >>> >> >> > |
Re: How to copy a CompiledMethod?
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In reply to this post by Gabriel Hernán Barbuto
Gabriel, I am also interested in being able to completly copy a CompiledMethod. Do you have in mind to open a ticket and integrate it to Pharo?
thanks mariano On Fri, Nov 26, 2010 at 6:14 PM, Gabriel Hernán Barbuto <[hidden email]> wrote: Eliot |
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