X-Git-Url: http://plrg.eecs.uci.edu/git/?a=blobdiff_plain;f=lib%2FCodeGen%2FSpillPlacement.h;h=03dd58d6e9a978a52f13d03f5eb2112af5b4d36e;hb=844145720c0895226ab7cc4124af8ea19da57a5b;hp=a67785ddf9b0e20c5044af0179d7117956cfcab4;hpb=70d4370b47cdd375bbea98e50452789fe4f1af04;p=oota-llvm.git

diff --git a/lib/CodeGen/SpillPlacement.h b/lib/CodeGen/SpillPlacement.h
index a67785ddf9b..03dd58d6e9a 100644
--- a/lib/CodeGen/SpillPlacement.h
+++ b/lib/CodeGen/SpillPlacement.h
@@ -24,12 +24,13 @@
 //
 //===----------------------------------------------------------------------===//
 
-#ifndef LLVM_CODEGEN_SPILLPLACEMENT_H
-#define LLVM_CODEGEN_SPILLPLACEMENT_H
+#ifndef LLVM_LIB_CODEGEN_SPILLPLACEMENT_H
+#define LLVM_LIB_CODEGEN_SPILLPLACEMENT_H
 
 #include "llvm/ADT/ArrayRef.h"
 #include "llvm/ADT/SmallVector.h"
 #include "llvm/CodeGen/MachineFunctionPass.h"
+#include "llvm/Support/BlockFrequency.h"
 
 namespace llvm {
 
@@ -37,29 +38,39 @@ class BitVector;
 class EdgeBundles;
 class MachineBasicBlock;
 class MachineLoopInfo;
+class MachineBlockFrequencyInfo;
 
-class SpillPlacement  : public MachineFunctionPass {
+class SpillPlacement : public MachineFunctionPass {
   struct Node;
   const MachineFunction *MF;
   const EdgeBundles *bundles;
   const MachineLoopInfo *loops;
+  const MachineBlockFrequencyInfo *MBFI;
   Node *nodes;
 
   // Nodes that are active in the current computation. Owned by the prepare()
   // caller.
   BitVector *ActiveNodes;
 
-  // The number of active nodes with a positive bias.
-  unsigned PositiveNodes;
+  // Nodes with active links. Populated by scanActiveBundles.
+  SmallVector<unsigned, 8> Linked;
+
+  // Nodes that went positive during the last call to scanActiveBundles or
+  // iterate.
+  SmallVector<unsigned, 8> RecentPositive;
 
   // Block frequencies are computed once. Indexed by block number.
-  SmallVector<float, 4> BlockFrequency;
+  SmallVector<BlockFrequency, 8> BlockFrequencies;
+
+  /// Decision threshold. A node gets the output value 0 if the weighted sum of
+  /// its inputs falls in the open interval (-Threshold;Threshold).
+  BlockFrequency Threshold;
 
 public:
   static char ID; // Pass identification, replacement for typeid.
 
-  SpillPlacement() : MachineFunctionPass(ID), nodes(0) {}
-  ~SpillPlacement() { releaseMemory(); }
+  SpillPlacement() : MachineFunctionPass(ID), nodes(nullptr) {}
+  ~SpillPlacement() override { releaseMemory(); }
 
   /// BorderConstraint - A basic block has separate constraints for entry and
   /// exit.
@@ -67,6 +78,7 @@ public:
     DontCare,  ///< Block doesn't care / variable not live.
     PrefReg,   ///< Block entry/exit prefers a register.
     PrefSpill, ///< Block entry/exit prefers a stack slot.
+    PrefBoth,  ///< Block entry prefers both register and stack.
     MustSpill  ///< A register is impossible, variable must be spilled.
   };
 
@@ -75,6 +87,11 @@ public:
     unsigned Number;            ///< Basic block number (from MBB::getNumber()).
     BorderConstraint Entry : 8; ///< Constraint on block entry.
     BorderConstraint Exit : 8;  ///< Constraint on block exit.
+
+    /// True when this block changes the value of the live range. This means
+    /// the block has a non-PHI def.  When this is false, a live-in value on
+    /// the stack can be live-out on the stack without inserting a spill.
+    bool ChangesValue;
   };
 
   /// prepare - Reset state and prepare for a new spill placement computation.
@@ -89,14 +106,34 @@ public:
   /// addConstraints - Add constraints and biases. This method may be called
   /// more than once to accumulate constraints.
   /// @param LiveBlocks Constraints for blocks that have the variable live in or
-  ///                   live out. DontCare/DontCare means the variable is live
-  ///                   through the block. DontCare/X means the variable is live
-  ///                   out, but not live in.
+  ///                   live out.
   void addConstraints(ArrayRef<BlockConstraint> LiveBlocks);
 
-  /// getPositiveNodes - Return the total number of graph nodes with a positive
-  /// bias after adding constraints.
-  unsigned getPositiveNodes() const { return PositiveNodes; }
+  /// addPrefSpill - Add PrefSpill constraints to all blocks listed.  This is
+  /// equivalent to calling addConstraint with identical BlockConstraints with
+  /// Entry = Exit = PrefSpill, and ChangesValue = false.
+  ///
+  /// @param Blocks Array of block numbers that prefer to spill in and out.
+  /// @param Strong When true, double the negative bias for these blocks.
+  void addPrefSpill(ArrayRef<unsigned> Blocks, bool Strong);
+
+  /// addLinks - Add transparent blocks with the given numbers.
+  void addLinks(ArrayRef<unsigned> Links);
+
+  /// scanActiveBundles - Perform an initial scan of all bundles activated by
+  /// addConstraints and addLinks, updating their state. Add all the bundles
+  /// that now prefer a register to RecentPositive.
+  /// Prepare internal data structures for iterate.
+  /// Return true is there are any positive nodes.
+  bool scanActiveBundles();
+
+  /// iterate - Update the network iteratively until convergence, or new bundles
+  /// are found.
+  void iterate();
+
+  /// getRecentPositive - Return an array of bundles that became positive during
+  /// the previous call to scanActiveBundles or iterate.
+  ArrayRef<unsigned> getRecentPositive() { return RecentPositive; }
 
   /// finish - Compute the optimal spill code placement given the
   /// constraints. No MustSpill constraints will be violated, and the smallest
@@ -109,17 +146,17 @@ public:
 
   /// getBlockFrequency - Return the estimated block execution frequency per
   /// function invocation.
-  float getBlockFrequency(unsigned Number) const {
-    return BlockFrequency[Number];
+  BlockFrequency getBlockFrequency(unsigned Number) const {
+    return BlockFrequencies[Number];
   }
 
 private:
-  virtual bool runOnMachineFunction(MachineFunction&);
-  virtual void getAnalysisUsage(AnalysisUsage&) const;
-  virtual void releaseMemory();
+  bool runOnMachineFunction(MachineFunction&) override;
+  void getAnalysisUsage(AnalysisUsage&) const override;
+  void releaseMemory() override;
 
   void activate(unsigned);
-  void iterate(const SmallVectorImpl<unsigned>&);
+  void setThreshold(const BlockFrequency &Entry);
 };
 
 } // end namespace llvm