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Bug 162

Summary: GDC unable to de-virtualise method calls
Product: GDC Reporter: Iain Buclaw <ibuclaw>
Component: gdcAssignee: Iain Buclaw <ibuclaw>
Status: NEW ---    
Severity: enhancement    
Priority: ---    
Version: development   
Hardware: All   
OS: All   

Description Iain Buclaw 2014-10-26 10:37:29 CET 
Currently we emit method calls as the following:

  *(c->__vptr + 40) (c, 1, 2, 3);

Which translate directly into the following trees:

  indirect_ref(pointer_plus(component_ref(c, __vptr), 40))


GCC provides a more simplistic tree code called obj_type_ref, which represents a virtual method lookup, and given the binfo structure we already pass to the backed, this would give a chance for the optimiser passes to statically determine the dynamic type of the object and devirtualise the call.

  obj_type_ref(component_ref(c, __vptr), c, 40)