//
// The LLVM Compiler Infrastructure
//
-// This file was developed by the LLVM research group and is distributed under
-// the University of Illinois Open Source License. See LICENSE.TXT for details.
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
-// 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/DenseSet.h"
+#include "llvm/MC/SectionKind.h"
+#include <cassert>
+#include <climits>
#include <vector>
namespace llvm {
class Constant;
+class FoldingSetNodeID;
+class DataLayout;
+class TargetMachine;
+class Type;
+class MachineConstantPool;
+class raw_ostream;
+
+/// Abstract base class for all machine specific constantpool value subclasses.
+///
+class MachineConstantPoolValue {
+ virtual void anchor();
+ Type *Ty;
-class MachineConstantPool {
- std::vector<Constant*> Constants;
public:
+ explicit MachineConstantPoolValue(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;
+ Type *getType() const { return Ty; }
+
+ /// getRelocationInfo - This method classifies the entry according to
+ /// whether or not it may generate a relocation entry. This must be
+ /// conservative, so if it might codegen to a relocatable entry, it should say
+ /// so. The return values are the same as Constant::getRelocationInfo().
+ virtual unsigned getRelocationInfo() const = 0;
+
+ virtual int getExistingMachineCPValue(MachineConstantPool *CP,
+ unsigned Alignment) = 0;
+
+ virtual void addSelectionDAGCSEId(FoldingSetNodeID &ID) = 0;
+
+ /// print - Implement operator<<
+ virtual void print(raw_ostream &O) const = 0;
+};
+
+inline raw_ostream &operator<<(raw_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 {
+ const Constant *ConstVal;
+ MachineConstantPoolValue *MachineCPVal;
+ } Val;
+
+ /// The required alignment for this entry. The top bit is set when Val is
+ /// a target specific MachineConstantPoolValue.
+ unsigned Alignment;
+
+ MachineConstantPoolEntry(const Constant *V, unsigned A)
+ : Alignment(A) {
+ Val.ConstVal = V;
+ }
+ MachineConstantPoolEntry(MachineConstantPoolValue *V, unsigned A)
+ : Alignment(A) {
+ Val.MachineCPVal = V;
+ Alignment |= 1U << (sizeof(unsigned)*CHAR_BIT-1);
+ }
+
+ /// isMachineConstantPoolEntry - Return true if the MachineConstantPoolEntry
+ /// is indeed a target specific constantpool entry, not a wrapper over a
+ /// Constant.
+ bool isMachineConstantPoolEntry() const {
+ return (int)Alignment < 0;
+ }
+
+ int getAlignment() const {
+ return Alignment & ~(1 << (sizeof(unsigned)*CHAR_BIT-1));
}
+ Type *getType() const;
+
+ /// getRelocationInfo - This method classifies the entry according to
+ /// whether or not it may generate a relocation entry. This must be
+ /// conservative, so if it might codegen to a relocatable entry, it should say
+ /// so. The return values are:
+ ///
+ /// 0: This constant pool entry is guaranteed to never have a relocation
+ /// applied to it (because it holds a simple constant like '4').
+ /// 1: This entry has relocations, but the entries are guaranteed to be
+ /// resolvable by the static linker, so the dynamic linker will never see
+ /// them.
+ /// 2: This entry may have arbitrary relocations.
+ unsigned getRelocationInfo() const;
+
+ SectionKind getSectionKind(const DataLayout *DL) 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 {
+ unsigned PoolAlignment; ///< The alignment for the pool.
+ std::vector<MachineConstantPoolEntry> Constants; ///< The pool of constants.
+ /// MachineConstantPoolValues that use an existing MachineConstantPoolEntry.
+ DenseSet<MachineConstantPoolValue*> MachineCPVsSharingEntries;
+ const DataLayout &DL;
+
+ const DataLayout &getDataLayout() const { return DL; }
+
+public:
+ /// @brief The only constructor.
+ explicit MachineConstantPool(const DataLayout &DL)
+ : PoolAlignment(1), DL(DL) {}
+ ~MachineConstantPool();
+
+ /// getConstantPoolAlignment - Return 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 the minimum required alignment for
+ /// the object.
+ unsigned getConstantPoolIndex(const 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(raw_ostream &OS) const;
- /// dump - Call print(std::cerr) to be called from the debugger.
+ /// dump - Call print(cerr) to be called from the debugger.
void dump() const;
};
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