641036 - Add ASSERT to catch incorrect declaration of GCMember

Status: RESOLVED FIXED

(Tamarin Graveyard :: Garbage Collection (mmGC), defect, P2)

Description

[Brent Getlin]

Within the scope of a GC defined object (GCRoot, GCObject, GCFinalizedObject) method it's possible to declare a GCMember on the stack.  


void MyGCObject::MyFoo()
{

    //  This will likely cause crash as it attempts to add a write barrier to the stack 
    GCMember<GCObject> crash;

}


Solve it with a check on construction of the GCMember to see if the memory address is on the stack:

#ifdef DEBUG
        
        static bool IsAddressOnStack(void *address)
        {
                
                uintptr_t stackBase = VMPI_getThreadStackBase();
                char stackTop;
                return ((uintptr_t)address > (uintptr_t)&stackTop && (uintptr_t)address < stackBase);
                
        }
#endif

Comment 1

[Tommy Reilly]

Attachment: MErge GCMember-inlines.h and GCMemberBase-inlines and apply assert to all GCMember ctors

Comment 2

[Lars T Hansen]

Comment on attachment 526290 [details] [diff] [review]
MErge GCMember-inlines.h and GCMemberBase-inlines and apply assert to all GCMember ctors

Not clear to me why you're checking "&(this->t)" and not simply "this".

Comment 3

[Tommy Reilly]

(In reply to comment #2)
> Not clear to me why you're checking "&(this->t)" and not simply "this".

Me neither.

Comment 4

[Tommy Reilly]

http://hg.mozilla.org/tamarin-redux/rev/57bcf95e5583