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D.gnu - [Bug 162] New: GDC unable to de-virtualise method calls

Date: Sun, 26 Oct 2014 10:37:29 +0000
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http://bugzilla.gdcproject.org/show_bug.cgi?id=162

            Bug ID: 162
           Summary: GDC unable to de-virtualise method calls
           Product: GDC
           Version: development
          Hardware: All
                OS: All
            Status: NEW
          Severity: enhancement
          Priority: Normal
         Component: gdc
          Assignee: ibuclaw gdcproject.org
          Reporter: ibuclaw gdcproject.org

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)

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Oct 26 2014