X-Git-Url: http://demsky.eecs.uci.edu/git/?a=blobdiff_plain;f=include%2Fllvm%2FCodeGen%2FMachineConstantPool.h;h=f05a540d38e5b992a1ea9a009929c7a62098cdf7;hb=80a75bfae980df96f969f1c05b0c4a80ce975240;hp=47148e8dd1118e3698d50fff8d7d68c96c3d1263;hpb=1ed38fb9a71150343dc9625e1808836b7f86d8f6;p=oota-llvm.git

diff --git a/include/llvm/CodeGen/MachineConstantPool.h b/include/llvm/CodeGen/MachineConstantPool.h
index 47148e8dd11..f05a540d38e 100644
--- a/include/llvm/CodeGen/MachineConstantPool.h
+++ b/include/llvm/CodeGen/MachineConstantPool.h
@@ -7,57 +7,141 @@
 //
 //===----------------------------------------------------------------------===//
 //
-// The MachineConstantPool class keeps track of constants referenced by a
-// function which must be spilled to memory.  This is used for constants which
-// are unable to be used directly as operands to instructions, which typically
-// include floating point and large integer constants.
-//
-// Instructions reference the address of these constant pool constants through
-// the use of MO_ConstantPoolIndex values.  When emitting assembly or machine
-// code, these virtual address references are converted to refer to the
-// address of the function constant pool values.
+/// @file This file declares the MachineConstantPool class which is an abstract
+/// constant pool to keep track of constants referenced by a function.
 //
 //===----------------------------------------------------------------------===//
 
 #ifndef LLVM_CODEGEN_MACHINECONSTANTPOOL_H
 #define LLVM_CODEGEN_MACHINECONSTANTPOOL_H
 
+#include "llvm/ADT/FoldingSet.h"
+#include "llvm/CodeGen/SelectionDAGNodes.h"
+#include "llvm/Support/Streams.h"
 #include <vector>
+#include <iosfwd>
 
 namespace llvm {
 
+class AsmPrinter;
 class Constant;
+class TargetData;
+class TargetMachine;
+class MachineConstantPool;
+
+/// Abstract base class for all machine specific constantpool value subclasses.
+///
+class MachineConstantPoolValue {
+  const Type *Ty;
 
-class MachineConstantPool {
-  std::vector<Constant*> Constants;
 public:
+  explicit MachineConstantPoolValue(const Type *ty) : Ty(ty) {}
+  virtual ~MachineConstantPoolValue() {}
 
-  /// getConstantPoolIndex - Create a new entry in the constant pool or return
-  /// an existing one.
+  /// getType - get type of this MachineConstantPoolValue.
   ///
-  unsigned getConstantPoolIndex(Constant *C) {
-    // Check to see if we already have this constant.
-    //
-    // FIXME, this could be made much more efficient for large constant pools.
-    for (unsigned i = 0, e = Constants.size(); i != e; ++i)
-      if (Constants[i] == C)
-        return i;
-    Constants.push_back(C);
-    return Constants.size()-1;
+  inline const Type *getType() const { return Ty; }
+
+  virtual int getExistingMachineCPValue(MachineConstantPool *CP,
+                                        unsigned Alignment) = 0;
+
+  virtual void AddSelectionDAGCSEId(FoldingSetNodeID &ID) = 0;
+
+  /// print - Implement operator<<...
+  ///
+  virtual void print(std::ostream &O) const = 0;
+  void print(std::ostream *O) const { if (O) print(*O); }
+};
+
+inline std::ostream &operator<<(std::ostream &OS,
+                                const MachineConstantPoolValue &V) {
+  V.print(OS);
+  return OS;
+}
+
+/// This class is a data container for one entry in a MachineConstantPool.
+/// It contains a pointer to the value and an offset from the start of
+/// the constant pool.
+/// @brief An entry in a MachineConstantPool
+class MachineConstantPoolEntry {
+public:
+  /// The constant itself.
+  union {
+    Constant *ConstVal;
+    MachineConstantPoolValue *MachineCPVal;
+  } Val;
+
+  /// The offset of the constant from the start of the pool. The top bit is set
+  /// when Val is a MachineConstantPoolValue.
+  unsigned Offset;
+
+  MachineConstantPoolEntry(Constant *V, unsigned O)
+    : Offset(O) {
+    assert((int)Offset >= 0 && "Offset is too large");
+    Val.ConstVal = V;
+  }
+  MachineConstantPoolEntry(MachineConstantPoolValue *V, unsigned O)
+    : Offset(O){
+    assert((int)Offset >= 0 && "Offset is too large");
+    Val.MachineCPVal = V; 
+    Offset |= 1 << (sizeof(unsigned)*8-1);
+  }
+
+  bool isMachineConstantPoolEntry() const {
+    return (int)Offset < 0;
   }
 
+  int getOffset() const { 
+    return Offset & ~(1 << (sizeof(unsigned)*8-1));
+  }
+
+  const Type *getType() const;
+};
+  
+/// The MachineConstantPool class keeps track of constants referenced by a
+/// function which must be spilled to memory.  This is used for constants which
+/// are unable to be used directly as operands to instructions, which typically
+/// include floating point and large integer constants.
+///
+/// Instructions reference the address of these constant pool constants through
+/// the use of MO_ConstantPoolIndex values.  When emitting assembly or machine
+/// code, these virtual address references are converted to refer to the
+/// address of the function constant pool values.
+/// @brief The machine constant pool.
+class MachineConstantPool {
+  const TargetData *TD;   ///< The machine's TargetData.
+  unsigned PoolAlignment; ///< The alignment for the pool.
+  std::vector<MachineConstantPoolEntry> Constants; ///< The pool of constants.
+public:
+  /// @brief The only constructor.
+  explicit MachineConstantPool(const TargetData *td)
+    : TD(td), PoolAlignment(1) {}
+  ~MachineConstantPool();
+    
+  /// getConstantPoolAlignment - Return the log2 of the alignment required by
+  /// the whole constant pool, of which the first element must be aligned.
+  unsigned getConstantPoolAlignment() const { return PoolAlignment; }
+  
+  /// getConstantPoolIndex - Create a new entry in the constant pool or return
+  /// an existing one.  User must specify an alignment in bytes for the object.
+  unsigned getConstantPoolIndex(Constant *C, unsigned Alignment);
+  unsigned getConstantPoolIndex(MachineConstantPoolValue *V,unsigned Alignment);
+  
   /// isEmpty - Return true if this constant pool contains no constants.
-  ///
   bool isEmpty() const { return Constants.empty(); }
 
-  const std::vector<Constant*> &getConstants() const { return Constants; }
+  const std::vector<MachineConstantPoolEntry> &getConstants() const {
+    return Constants;
+  }
 
   /// print - Used by the MachineFunction printer to print information about
-  /// stack objects.  Implemented in MachineFunction.cpp
+  /// constant pool objects.  Implemented in MachineFunction.cpp
   ///
   void print(std::ostream &OS) const;
+  void print(std::ostream *OS) const { if (OS) print(*OS); }
 
   /// dump - Call print(std::cerr) to be called from the debugger.
+  ///
   void dump() const;
 };