Generalize statepoint lowering to use ImmutableStatepoint. Move statepoint lowering into a separate function 'LowerStatepoint' which uses ImmutableStatepoint instead of a CallInst. Also related utility functions are changed to receive ImmutableCallSite.

Differential Revision: http://reviews.llvm.org/D7756 

llvm-svn: 230017
diff --git a/llvm/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.h b/llvm/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.h
index 30cc125..ad7411f 100644
--- a/llvm/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.h
+++ b/llvm/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.h
@@ -20,6 +20,7 @@
 #include "llvm/CodeGen/SelectionDAG.h"
 #include "llvm/CodeGen/SelectionDAGNodes.h"
 #include "llvm/IR/CallSite.h"
+#include "llvm/IR/Statepoint.h"
 #include "llvm/IR/Constants.h"
 #include "llvm/Support/ErrorHandling.h"
 #include "llvm/Target/TargetLowering.h"
@@ -660,6 +661,8 @@
   /// references that need to refer to the last resulting block.
   void UpdateSplitBlock(MachineBasicBlock *First, MachineBasicBlock *Last);
 
+  // This function is responsible for the whole statepoint lowering process.
+  void LowerStatepoint(ImmutableStatepoint Statepoint);
 private:
   std::pair<SDValue, SDValue> lowerInvokable(
           TargetLowering::CallLoweringInfo &CLI,