Garbage Collection, pointers and scope in D - garbage-collection

Question

Apologies in advance about the long post - I'm having a problem I think might be related to garbage collection.
I have a class that wraps DMDScript like this:
/**
* Wrapper class for the DMDScript
*/
class ScriptingHost
{
protected static CallContext *cc ; // Call Context for interaction with the script.
protected static Program prg ; // Reference to program object (this is where the script buffer gets parsed)
static this()
{
// create our program instance
prg = new Program();
// create reference to call Context
cc = prg.callcontext;
Stdout( "cc.global: " )( cc.global ).newline ;
// add some built-in functions, like trace() and trigger()
DnativeFunction dnfTrace = new DnativeFunction( &jsTrace, "trace", 0, Dfunction.getPrototype() ) ;
DnativeFunction dnfTrigger = new DnativeFunction( &jsTrigger, "trigger", 0, Dfunction.getPrototype() ) ;
// add it to the call context
cc.global.Put("trace", dnfTrace , 0);
cc.global.Put("trigger", dnfTrigger , 0);
}
/***********************************************************************
* Helper functions for D<-->JS interaction
************************************************************************/
/**
* Trace (output)
*/
protected static void* jsTrace( Dobject pthis, CallContext* cc, Dobject othis, Value* ret, Value[] arglist)
{
Stdout( "<<" )( arglist ).newline ;
return null;
}
/**
* Trigger
*/
protected static void* jsTrigger( Dobject pthis, CallContext* cc, Dobject othis, Value* ret, Value[] arglist)
{
Stdout( "<<" )( arglist ).newline ;
return null;
}
}
So far, everything is fine and I can run the code with no errors.
Output:
cc.global: dmdscript_tango.dglobal.Dglobal
I also added a method to ScriptingHost that traced the cc.global object:
public static void testGlobal()
{
Stdout( "testGlobal: " )( cc.global ).newline.flush ;
}
...which also works fine - The problem arises when I try accessing it from outside the class ala:
int main()
{
Stdout( "DMDScriptTest" ).newline ;
ScriptingHost.testGlobal() ;
Stdout( "global: " )( ScriptingHost.global() ).newline.flush ;
ScriptingHost.testGlobal() ;
}
Then I get the following error:
cc.global: dmdscript_tango.dglobal.Dglobal
DMDScriptTest
testGlobal: dmdscript_tango.dglobal.Dglobal
object.Exception: Illegal Instruction
----------------
[ 5fd264] 0+0 ??? #0+1975211 :0
[ 404e05] 0+0 tango.text.convert.Layout.Layout!(char).Layout.parse.process #0+29 c:\dmd\dmd\bin\..\import\tango\text\convert\Layout.d:595
[ 404875] 0+0 tango.text.convert.Layout.Layout!(char).Layout.parse #0+65 c:\dmd\dmd\bin\..\import\tango\text\convert\Layout.d:603
[ 40463b] 0+0 tango.text.convert.Layout.Layout!(char).Layout.convert #0+34 c:\dmd\dmd\bin\..\import\tango\text\convert\Layout.d:347
[ 40418e] 0+0 tango.io.stream.Format.FormatOutput!(char).FormatOutput.print #0+67 c:\dmd\dmd\bin\..\import\tango\io\stream\Format.d:172
[ 40206c] 0+0 __Dmain #0+45 test2.d:87
[ 4380b5] 0+0 rt.compiler.dmd.rt.dmain2.main.runMain #0+119292 :0
[ 43800b] 0+0 rt.compiler.dmd.rt.dmain2.main.tryExec #0+119122 :0
[ 4380f3] 0+0 rt.compiler.dmd.rt.dmain2.main.runAll #0+119354 :0
[ 43800b] 0+0 rt.compiler.dmd.rt.dmain2.main.tryExec #0+119122 :0
[ 437fc3] 0+0 _main #0+119050 :0
[ 44c980] 0+0 _mainCRTStartup #0+203463 :0
[75e133c8] 0+0 ??? #0+1973388559 :0
[76f49ed0] 0+0 ??? #0+1991438359 :0
[76f49ea0] 0+0 ??? #0+1991438311 :0
global: unittest start
unittest end
Is anyone able to shed some light on the issue here - and perhaps how to work around it, please? :)
edit: I am using a windows D1-Tango setup. The version I'm using is the 0.99.9 Tango/DMD 1.056 Kai bundle .
thanks,

Answer 1

First of all, which operating system are you using? Based on the error I'm guessing windows? Which version of dmd/tango are you using? 32 bit or 64 bit? Try running your application through a disassembler and looking what instruction is listed at 5fd264 (search through the output). We should be able to help more with some of the information above.

Answer 2

What version of DMD are you using? If you're still using 1.067, are compiling in 64-bit mode and are using sufficiently ancient hardware, you may have a problem. 1.067 was the first version with 64-bit support and had a bug that would use the LAHF and SAHF instructions, which weren't supported on very old 64-bit CPUs.