Subzero, MIPS32: Atomic intrinsics fixes

src/IceTargetLowering.h

 //===- subzero/src/IceTargetLowering.h - Lowering interface -----*- C++ -*-===//
 //
 //                        The Subzero Code Generator
 //
 // This file is distributed under the University of Illinois Open Source
 // License. See LICENSE.TXT for details.
 //
 //===----------------------------------------------------------------------===//
 ///
 /// \file
@@ skipping 235 matching lines @@
   virtual bool hasFramePointer() const { return false; }
   virtual void setHasFramePointer() = 0;
   virtual RegNumT getStackReg() const = 0;
   virtual RegNumT getFrameReg() const = 0;
   virtual RegNumT 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;
   virtual uint32_t maxOutArgsSizeBytes() const { return 0; }
-
+  // Addressing relative to frame pointer differs in MIPS compared to X86/ARM
+  // since MIPS decrements its stack pointer prior to saving it in the frame
+  // pointer register.
+  virtual uint32_t getFramePointerOffset(uint32_t CurrentOffset,
+                                         uint32_t Size) const {
+    return -(CurrentOffset + Size);
+  }
   /// Return whether a 64-bit Variable should be split into a Variable64On32.
   virtual bool shouldSplitToVariable64On32(Type Ty) const = 0;
 
   /// Return whether a Vector Variable should be split into a VariableVecOn32.
   virtual bool shouldSplitToVariableVecOn32(Type Ty) const {
     (void)Ty;
     return false;
   }
 
   bool hasComputedFrame() const { return HasComputedFrame; }
@@ skipping 380 matching lines @@
   virtual void lower() {}
 
 protected:
   explicit TargetHeaderLowering(GlobalContext *Ctx) : Ctx(Ctx) {}
   GlobalContext *Ctx;
 };
 
 } // end of namespace Ice
 
 #endif // SUBZERO_SRC_ICETARGETLOWERING_H