Subzero, MIPS32: Handling floating point instructions fadd, fsub, fmul, fdiv

src/IceTargetLoweringMIPS32.h

Index: src/IceTargetLoweringMIPS32.h
diff --git a/src/IceTargetLoweringMIPS32.h b/src/IceTargetLoweringMIPS32.h
index 3366dcea677cec844f82fdebbc75e05d8250ee9f..cfbaa6f2d4b5f56af050441e23b2bfdf2105499d 100644
--- a/src/IceTargetLoweringMIPS32.h
+++ b/src/IceTargetLoweringMIPS32.h
@@ -447,6 +447,11 @@ public:
   static Type stackSlotType();
   Variable *copyToReg(Operand *Src, RegNumT RegNum = RegNumT());
 
+  // Iterates over the CFG and determines the maximum outgoing stack arguments
+  // bytes. This information is later used during addProlog() to pre-allocate
+  // the outargs area
+  void findMaxStackOutArgsSize();
+
   void addProlog(CfgNode *Node) override;
   void addEpilog(CfgNode *Node) override;
 
@@ -457,8 +462,48 @@ public:
   Operand *loOperand(Operand *Operand);
   Operand *hiOperand(Operand *Operand);
 
+  void finishArgumentLowering(Variable *Arg, Variable *FramePtr,
+                              size_t BasicFrameOffset, size_t *InArgsSizeBytes);
+
   Operand *legalizeUndef(Operand *From, RegNumT RegNum = RegNumT());
 
+  /// Helper class that understands the Calling Convention and register
+  /// assignments as per MIPS O32 abi.
+  class CallingConv {
+    CallingConv(const CallingConv &) = delete;
+    CallingConv &operator=(const CallingConv &) = delete;
+
+  public:
+    CallingConv();
+    ~CallingConv() = default;
+
+    /// argInReg returns true if there is a Register available for the requested
+    /// type, and false otherwise. If it returns true, Reg is set to the
+    /// appropriate register number. Note that, when Ty == IceType_i64, Reg will
+    /// be an I64 register pair.
+    bool argInReg(Type Ty, uint32_t ArgNo, RegNumT *Reg);
+
+  private:
+    // argInGPR is used to find if any GPR register is available for argument of
+    // type Ty
+    bool argInGPR(Type Ty, RegNumT *Reg);
+    /// argInVFP is to floating-point/vector types what argInGPR is for integer
+    /// types.
+    bool argInVFP(Type Ty, RegNumT *Reg);
+    inline void discardNextGPRAndItsAliases(CfgVector<RegNumT> *Regs);
+    void discardUnavailableGPRsAndTheirAliases(CfgVector<RegNumT> *Regs);
+    SmallBitVector GPRegsUsed;
+    CfgVector<RegNumT> GPRArgs;
+    CfgVector<RegNumT> I64Args;
+
+    void discardUnavailableVFPRegsAndTheirAliases(CfgVector<RegNumT> *Regs);
+    SmallBitVector VFPRegsUsed;
+    CfgVector<RegNumT> FP32Args;
+    CfgVector<RegNumT> FP64Args;
+    // UseFPRegs is a flag indicating if FP registers can be used
+    bool UseFPRegs = false;
+  };
+
 protected:
   explicit TargetMIPS32(Cfg *Func);
 
@@ -506,13 +551,18 @@ protected:
 
   bool UsesFramePointer = false;
   bool NeedsStackAlignment = false;
+  bool MaybeLeafFunc = true;
+  bool PrologEmitsFixedAllocas = false;
+  uint32_t MaxOutArgsSizeBytes = 0;
   static SmallBitVector TypeToRegisterSet[RCMIPS32_NUM];
   static SmallBitVector TypeToRegisterSetUnfiltered[RCMIPS32_NUM];
   static SmallBitVector RegisterAliases[RegMIPS32::Reg_NUM];
   SmallBitVector RegsUsed;
   VarList PhysicalRegisters[IceType_NUM];
+  VarList PreservedGPRs;
   static constexpr uint32_t CHAR_BITS = 8;
   static constexpr uint32_t INT32_BITS = 32;
+  size_t SpillAreaSizeBytes = 0;
 
 private:
   ENABLE_MAKE_UNIQUE;