[Vm-dev] BUG? A problem with callbacks that shows up in 64bits (but is on 32bits too)

[Eliot Miranda]

Hi Esteban,

   turns out it is a Slang bug affecting the Cogit, specifically
pc-mapping.  The generateMapAt:start: method was being wrongly generated
with the following types:

    unsigned char annotation;
    usqIntptr_t delta;
    sqInt i;
    AbstractInstruction *instruction;
    sqInt length;
    usqIntptr_t location;
    usqIntptr_t mapEntry;
    sqInt maxDelta;
    usqIntptr_t mcpc;

whereas they should be

    unsigned char annotation;
    sqInt delta;
    sqInt i;
    AbstractInstruction *instruction;
    sqInt length;
    usqInt location;
    sqInt mapEntry;
    sqInt maxDelta;
    usqIntptr_t mcpc;

Specifically Slang was getting the type of unsigned - unsigned wrong,
answering unsigned instead of signed.  This is the operative expression:

      delta := mcpc - location / backEnd codeGranularity

where both mclc and location are unsigned.  I'm fixing this but now because
it is in Slang, and hence will very probably cause pervasive changes
throughout the generated source, I need to take care and not rush to a
fix.  I'll keep you posted.



On Fri, Mar 10, 2017 at 7:35 AM, Esteban Lorenzano <estebanlm at gmail.com>
wrote:

>
> Hi,
>
> I’m tumbling into an error in Pharo, because we use callbacks intensively,
> in Athens(cairo)-to-World conversion in particular, and people is sending
> always their crash reports… we made the whole conversion a lot more robust
> since problems started to arise, but now I hit a wall I cannot solve: I
> think problem is in something in callbacks.
>
> And problem is showing very easy on 64bits (while in 32bits it takes time
> and is more random).
>
> Here is the easiest way to reproduce it (in mac):
>
> wget files.pharo.org/get-files/60/pharo64-mac-latest.zip
> wget files.pharo.org/get-files/60/pharo64.zip
> wget files.pharo.org/get-files/60/sources.zip
> unzip pharo64-mac-latest.zip
> unzip pharo64.zip
> unzip sources.zip
> ./Pharo.app/Contents/MacOS/Pharo ./Pharo64-60438.image eval "VGTigerDemo
> runDemo"
>
> eventually (like 5-6 seconds after, if not immediately), you will have a
> stack like this:
>
> SmallInteger(Object)>>primitiveFailed:
> SmallInteger(Object)>>primitiveFailed
> SmallInteger(VMCallbackContext64)>>primSignal:andReturnAs:fromContext:
> GrafPort>>copyBits
> GrafPort>>image:at:sourceRect:rule:
> FormCanvas>>image:at:sourceRect:rule:
> FormCanvas(Canvas)>>drawImage:at:sourceRect:
> FormCanvas(Canvas)>>drawImage:at:
> VGTigerDemo>>runDemo
> VGTigerDemo class>>runDemo
> UndefinedObject>>DoIt
> OpalCompiler>>evaluate
> OpalCompiler(AbstractCompiler)>>evaluate:
> [ result := Smalltalk compiler evaluate: aStream.
> self hasSessionChanged
>         ifFalse: [ self stdout
>                         print: result;
>                         lf ] ] in EvaluateCommandLineHandler>>evaluate:
> in Block: [ result := Smalltalk compiler evaluate: aStream....
> BlockClosure>>on:do:
> EvaluateCommandLineHandler>>evaluate:
> EvaluateCommandLineHandler>>evaluateArguments
> EvaluateCommandLineHandler>>activate
> EvaluateCommandLineHandler class(CommandLineHandler class)>>activateWith:
> [ aCommandLinehandler activateWith: commandLine ] in
> PharoCommandLineHandler(BasicCommandLineHandler)>>activateSubCommand: in
> Block: [ aCommandLinehandler activateWith: commandLine ]
> BlockClosure>>on:do:
> PharoCommandLineHandler(BasicCommandLineHandler)>>activateSubCommand:
> PharoCommandLineHandler(BasicCommandLineHandler)>>handleSubcommand
> PharoCommandLineHandler(BasicCommandLineHandler)>>handleArgument:
> [ self
>         handleArgument:
>                 (self arguments
>                         ifEmpty: [ '' ]
>                         ifNotEmpty: [ :arguments | arguments first ]) ] in
> PharoCommandLineHandler(BasicCommandLineHandler)>>activate in Block: [
> self...
> BlockClosure>>on:do:
> PharoCommandLineHandler(BasicCommandLineHandler)>>activate
> PharoCommandLineHandler>>activate
> PharoCommandLineHandler class(CommandLineHandler class)>>activateWith:
> [ super activateWith: aCommandLine ] in PharoCommandLineHandler
> class>>activateWith: in Block: [ super activateWith: aCommandLine ]
>
> Any idea?
>
> thanks!
> Esteban




-- 
_,,,^..^,,,_
best, Eliot
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