dfg/DFGLoopPreHeaderCreationPhase.h

   1 /*
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  25
  26 #ifndef DFGLoopPreHeaderCreationPhase_h
  27 #define DFGLoopPreHeaderCreationPhase_h
  28
  29 #if ENABLE(DFG_JIT)
  30
  31 namespace JSC { namespace DFG {
  32
  33 class BlockInsertionSet;
  34 class Graph;
  35 struct BasicBlock;
  36
  37 // Inserts dummy basic blocks before any loop headers that don't already have
  38 // a single non-loop predecessor.
  39
  40 bool performLoopPreHeaderCreation(Graph&);
  41
  42 // Creates a new basic block (a pre-header) that jumps to the given block. All
  43 // predecessors of the given block that aren't dominated by it are rerouted to
  44 // the pre-header.
  45 //
  46 // This function is used internally and it's used in a surgical fashion by
  47 // OSREntrypointCreationPhase.
  48 //
  49 // Note that executing this function requires having an intact dominators
  50 // analysis. You should run that analysis before doing damage to the CFG, even
  51 // if said damage is done before you call this.
  52 BasicBlock* createPreHeader(Graph&, BlockInsertionSet&, BasicBlock*);
  53
  54 } } // namespace JSC::DFG
  55
  56 #endif // ENABLE(DFG_JIT)
  57
  58 #endif // DFGLoopPreHeaderCreationPhase_h
  59