dfg/DFGStructureRegistrationPhase.h

   1 /*
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  25
  26 #ifndef DFGStructureRegistrationPhase_h
  27 #define DFGStructureRegistrationPhase_h
  28
  29 #if ENABLE(DFG_JIT)
  30
  31 namespace JSC { namespace DFG {
  32
  33 class Graph;
  34
  35 // Registers any structures we know about as weak references, and sets watchpoints on any
  36 // such structures that we know of that are currently watchable. It's somewhat
  37 // counterintuitive, but this ends up being the cleanest and most effective way of reducing
  38 // structure checks on terminal structures:
  39 //
  40 // - We used to only set watchpoints on watchable structures if we knew that this would
  41 //   remove a structure check. Experiments show that switching from that, to blindly
  42 //   setting watchpoints on all watchable structures, was not a regression.
  43 //
  44 // - It makes abstract interpretation a whole lot easier. We just assume that watchable
  45 //   structures are unclobberable without having to do any other logic.
  46
  47 bool performStructureRegistration(Graph&);
  48
  49 } } // namespace JSC::DFG
  50
  51 #endif // ENABLE(DFG_JIT)
  52
  53 #endif // DFGStructureRegistrationPhase_h
  54