Merge fixed alloca stack adjustments into the prolog

src/IceTargetLowering.h

Index: src/IceTargetLowering.h
diff --git a/src/IceTargetLowering.h b/src/IceTargetLowering.h
index aff423c44428e5d1ad489b370cba5564b13d290a..c613d99d072b7d45b338c381cc34ea11a63681a8 100644
--- a/src/IceTargetLowering.h
+++ b/src/IceTargetLowering.h
@@ -203,9 +203,12 @@ public:
   virtual bool hasFramePointer() const { return false; }
   virtual void setHasFramePointer() = 0;
   virtual SizeT getStackReg() const = 0;
+  virtual SizeT getFrameReg() const = 0;
   virtual SizeT getFrameOrStackReg() const = 0;
   virtual size_t typeWidthInBytesOnStack(Type Ty) const = 0;
   virtual uint32_t getStackAlignment() const = 0;
+  virtual void reserveFixedAllocaArea(size_t Size, size_t Align) = 0;
+  virtual int32_t getFrameFixedAllocaOffset() const = 0;
 
   /// Return whether a 64-bit Variable should be split into a Variable64On32.
   virtual bool shouldSplitToVariable64On32(Type Ty) const = 0;