Problems with latest VM

[Lee Salzman]

Try turning off global optimization in the function PSObjectHeap_pinCards and see
if things work. Please let us know ASAP!

Lee

On Sun, Aug 08, 2004 at 02:39:11PM +0200, Jaco van der Merwe wrote:
> Hi all,
> 
> I've just downloaded the latest VM and slate sources. I compiled the VM with
> Visual C++. I made both a debug and a release build. The debug build VM
> seems to work (at least it loads the image without problems). However, the
> release build fails fairly early while loading the image with an unhandled
> signal message, after which the VM exits.
> 
> The fact that the debug and release builds behave differently still
> indicates to me that the VM code accesses memory somewhere that is
> uninitialised, or not intended to be accessed. Therefore, although the debug
> build seems to run, it may be hiding the problem or just postponing it to
> many instructions later. I'm not sure how to proceed with debugging the
> unhandled signal case mostly because I don't understand the underlying
> mechanisms used in the vm. I'll appreciate it if someone can explain it to
> me. Then, maybe I'll be able to debug this case.
> 
> Also, when compiling the sources the compiler generates the following
> warning which seems suspicious to me:
> 
>    vm.c(3021) : warning C4047: '=' : 'ObjectPointer *' differs in levels of
> indirection from 'ObjectPointer (*)[]'
> 
> The offending line of code is as follows:
> 
>    vars = &lexicalContext->variables;
> 
> where vars and lexicalContext are defined as follows:
> 
>    ObjectPointer * vars;
>    struct LexicalContext * lexicalContext;
> 
> and LexicalContext is as follows:
> 
>    struct LexicalContext {
>       struct ObjectHeader header;
>       struct Map * map;
>       ObjectPointer traits;
>       ObjectPointer unwindBlock;
>       ObjectPointer variables[0];
>    };
> 
> This does not seem correct to me. Shouldn't the offending line of code read
> as follows?
> 
>    vars = lexicalContext->variables;
> 
> Also, the following suspicious warning still remains. This has previously
> been reported by me and other people.
> 
>    file.c(136) : warning C4146: unary minus operator applied to unsigned
> type, result still unsigned
> 
> The offending line of code is:
> 
>    PSObjectHeap_adjustAllOopsBy_ (CurrentMemory, - (unsigned)
> CurrentMemory -> memory);
> 
> where the function signature is:
> 
>    unsigned long int PSObjectHeap_adjustAllOopsBy_(struct ObjectHeap * h,
> unsigned long int shiftAmountInBytes)
> 
> Why give an explicit negative argument to a formal argument that is
> unsigned?
> 
> Regards
> 
> Jaco van der Merwe
>