vendor/llvm/llvm-trunk-r178860

1 files changed, 67 insertions, 26 deletions

diff --git a/include/llvm/CodeGen/RegisterScavenging.h b/include/llvm/CodeGen/RegisterScavenging.h
index 08d316992ec5..95bf29167c20 100644
--- a/include/llvm/CodeGen/RegisterScavenging.h
+++ b/include/llvm/CodeGen/RegisterScavenging.h
@@ -14,12 +14,12 @@
 //
 //===----------------------------------------------------------------------===//
 
-#ifndef LLVM_CODEGEN_REGISTER_SCAVENGING_H
-#define LLVM_CODEGEN_REGISTER_SCAVENGING_H
+#ifndef LLVM_CODEGEN_REGISTERSCAVENGING_H
+#define LLVM_CODEGEN_REGISTERSCAVENGING_H
 
+#include "llvm/ADT/BitVector.h"
 #include "llvm/CodeGen/MachineBasicBlock.h"
 #include "llvm/CodeGen/MachineRegisterInfo.h"
-#include "llvm/ADT/BitVector.h"
 
 namespace llvm {
 
@@ -40,21 +40,23 @@ class RegScavenger {
   /// registers.
   bool Tracking;
 
-  /// ScavengingFrameIndex - Special spill slot used for scavenging a register
-  /// post register allocation.
-  int ScavengingFrameIndex;
+  /// Information on scavenged registers (held in a spill slot).
+  struct ScavengedInfo {
+    ScavengedInfo(int FI = -1) : FrameIndex(FI), Reg(0), Restore(NULL) {}
 
-  /// ScavengedReg - If none zero, the specific register is currently being
-  /// scavenged. That is, it is spilled to the special scavenging stack slot.
-  unsigned ScavengedReg;
+    /// A spill slot used for scavenging a register post register allocation.
+    int FrameIndex;
 
-  /// ScavengedRC - Register class of the scavenged register.
-  ///
-  const TargetRegisterClass *ScavengedRC;
+    /// If non-zero, the specific register is currently being
+    /// scavenged. That is, it is spilled to this scavenging stack slot.
+    unsigned Reg;
 
-  /// ScavengeRestore - Instruction that restores the scavenged register from
-  /// stack.
-  const MachineInstr *ScavengeRestore;
+    /// The instruction that restores the scavenged register from stack.
+    const MachineInstr *Restore;
+  };
+
+  /// A vector of information on scavenged registers.
+  SmallVector<ScavengedInfo, 2> Scavenged;
 
   /// CalleeSavedrRegs - A bitvector of callee saved registers for the target.
   ///
@@ -71,8 +73,7 @@ class RegScavenger {
 
 public:
   RegScavenger()
-    : MBB(NULL), NumPhysRegs(0), Tracking(false),
-      ScavengingFrameIndex(-1), ScavengedReg(0), ScavengedRC(NULL) {}
+    : MBB(NULL), NumPhysRegs(0), Tracking(false) {}
 
   /// enterBasicBlock - Start tracking liveness from the begin of the specific
   /// basic block.
@@ -92,9 +93,25 @@ public:
     while (MBBI != I) forward();
   }
 
+  /// Invert the behavior of forward() on the current instruction (undo the
+  /// changes to the available registers made by forward()).
+  void unprocess();
+
+  /// Unprocess instructions until you reach the provided iterator.
+  void unprocess(MachineBasicBlock::iterator I) {
+    while (MBBI != I) unprocess();
+  }
+
   /// skipTo - Move the internal MBB iterator but do not update register states.
-  ///
-  void skipTo(MachineBasicBlock::iterator I) { MBBI = I; }
+  void skipTo(MachineBasicBlock::iterator I) {
+    if (I == MachineBasicBlock::iterator(NULL))
+      Tracking = false;
+    MBBI = I;
+  }
+
+  MachineBasicBlock::iterator getCurrentPosition() const {
+    return MBBI;
+  }
 
   /// getRegsUsed - return all registers currently in use in used.
   void getRegsUsed(BitVector &used, bool includeReserved);
@@ -107,10 +124,28 @@ public:
   /// Return 0 if none is found.
   unsigned FindUnusedReg(const TargetRegisterClass *RegClass) const;
 
-  /// setScavengingFrameIndex / getScavengingFrameIndex - accessor and setter of
-  /// ScavengingFrameIndex.
-  void setScavengingFrameIndex(int FI) { ScavengingFrameIndex = FI; }
-  int getScavengingFrameIndex() const { return ScavengingFrameIndex; }
+  /// Add a scavenging frame index.
+  void addScavengingFrameIndex(int FI) {
+    Scavenged.push_back(ScavengedInfo(FI));
+  }
+
+  /// Query whether a frame index is a scavenging frame index.
+  bool isScavengingFrameIndex(int FI) const {
+    for (SmallVector<ScavengedInfo, 2>::const_iterator I = Scavenged.begin(),
+         IE = Scavenged.end(); I != IE; ++I)
+      if (I->FrameIndex == FI)
+        return true;
+
+    return false;
+  }
+
+  /// Get an array of scavenging frame indices.
+  void getScavengingFrameIndices(SmallVectorImpl<int> &A) const {
+    for (SmallVector<ScavengedInfo, 2>::const_iterator I = Scavenged.begin(),
+         IE = Scavenged.end(); I != IE; ++I)
+      if (I->FrameIndex >= 0)
+        A.push_back(I->FrameIndex);
+  }
 
   /// scavengeRegister - Make a register of the specific register class
   /// available and do the appropriate bookkeeping. SPAdj is the stack
@@ -129,10 +164,12 @@ private:
   /// isReserved - Returns true if a register is reserved. It is never "unused".
   bool isReserved(unsigned Reg) const { return MRI->isReserved(Reg); }
 
-  /// isUsed / isUnused - Test if a register is currently being used.
+  /// isUsed - Test if a register is currently being used.  When called by the
+  /// isAliasUsed function, we only check isReserved if this is the original
+  /// register, not an alias register.
   ///
-  bool isUsed(unsigned Reg) const   {
-    return !RegsAvailable.test(Reg) || isReserved(Reg);
+  bool isUsed(unsigned Reg, bool CheckReserved = true) const   {
+    return !RegsAvailable.test(Reg) || (CheckReserved && isReserved(Reg));
   }
 
   /// isAliasUsed - Is Reg or an alias currently in use?
@@ -147,6 +184,10 @@ private:
     RegsAvailable |= Regs;
   }
 
+  /// Processes the current instruction and fill the KillRegs and DefRegs bit
+  /// vectors.
+  void determineKillsAndDefs();
+
   /// Add Reg and all its sub-registers to BV.
   void addRegWithSubRegs(BitVector &BV, unsigned Reg);