Merging r261441, r261447, and r261546:

[oota-llvm.git] / lib / Target / PowerPC / PPCFrameLowering.h

diff --git a/lib/Target/PowerPC/PPCFrameLowering.h b/lib/Target/PowerPC/PPCFrameLowering.h
index 28d074ecd79d8347482f0568ab5bc42447b72efe..f1f3f0b831a70b000587cf2806657f3ee5cc1c98 100644 (file)
--- a/lib/Target/PowerPC/PPCFrameLowering.h
+++ b/lib/Target/PowerPC/PPCFrameLowering.h
@@ -29,6 +29,43 @@ class PPCFrameLowering: public TargetFrameLowering {
   const unsigned LinkageSize;
   const unsigned BasePointerSaveOffset;
 
+  /**
+   * \brief Find register[s] that can be used in function prologue and epilogue
+   *
+   * Find register[s] that can be use as scratch register[s] in function
+   * prologue and epilogue to save various registers (Link Register, Base
+   * Pointer, etc.). Prefer R0/R12, if available. Otherwise choose whatever
+   * register[s] are available.
+   *
+   * This method will return true if it is able to find enough unique scratch
+   * registers (1 or 2 depending on the requirement). If it is unable to find
+   * enough available registers in the block, it will return false and set
+   * any passed output parameter that corresponds to a required unique register
+   * to PPC::NoRegister.
+   *
+   * \param[in] MBB The machine basic block to find an available register for
+   * \param[in] UseAtEnd Specify whether the scratch register will be used at
+   *                     the end of the basic block (i.e., will the scratch
+   *                     register kill a register defined in the basic block)
+   * \param[in] TwoUniqueRegsRequired Specify whether this basic block will
+   *                                  require two unique scratch registers.
+   * \param[out] SR1 The scratch register to use
+   * \param[out] SR2 The second scratch register. If this pointer is not null
+   *                 the function will attempt to set it to an available
+   *                 register regardless of whether there is a hard requirement
+   *                 for two unique scratch registers.
+   * \return true if the required number of registers was found.
+   *         false if the required number of scratch register weren't available.
+   *         If either output parameter refers to a required scratch register
+   *         that isn't available, it will be set to an invalid value.
+   */
+  bool findScratchRegister(MachineBasicBlock *MBB,
+                           bool UseAtEnd,
+                           bool TwoUniqueRegsRequired = false,
+                           unsigned *SR1 = nullptr,
+                           unsigned *SR2 = nullptr) const;
+  bool twoUniqueScratchRegsRequired(MachineBasicBlock *MBB) const;
+
 public:
   PPCFrameLowering(const PPCSubtarget &STI);
 
@@ -45,8 +82,8 @@ public:
   bool needsFP(const MachineFunction &MF) const;
   void replaceFPWithRealFP(MachineFunction &MF) const;
 
-  void processFunctionBeforeCalleeSavedScan(MachineFunction &MF,
-                                     RegScavenger *RS = nullptr) const override;
+  void determineCalleeSaves(MachineFunction &MF, BitVector &SavedRegs,
+                            RegScavenger *RS = nullptr) const override;
   void processFunctionBeforeFrameFinalized(MachineFunction &MF,
                                      RegScavenger *RS = nullptr) const override;
   void addScavengingSpillSlot(MachineFunction &MF, RegScavenger *RS) const;
@@ -92,6 +129,13 @@ public:
 
   const SpillSlot *
   getCalleeSavedSpillSlots(unsigned &NumEntries) const override;
+
+  bool enableShrinkWrapping(const MachineFunction &MF) const override;
+
+  /// Methods used by shrink wrapping to determine if MBB can be used for the
+  /// function prologue/epilogue.
+  bool canUseAsPrologue(const MachineBasicBlock &MBB) const override;
+  bool canUseAsEpilogue(const MachineBasicBlock &MBB) const override;
 };
 } // End llvm namespace