//
//===----------------------------------------------------------------------===//
//
-// 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;
};
projects / oota-llvm.git / blobdiff