| //===-- CodeGen/MachineJumpTableInfo.h - Abstract Jump Tables --*- C++ -*-===// |
| // |
| // The LLVM Compiler Infrastructure |
| // |
| // This file is distributed under the University of Illinois Open Source |
| // License. See LICENSE.TXT for details. |
| // |
| //===----------------------------------------------------------------------===// |
| // |
| // The MachineJumpTableInfo class keeps track of jump tables referenced by |
| // lowered switch instructions in the MachineFunction. |
| // |
| // Instructions reference the address of these jump tables through the use of |
| // MO_JumpTableIndex values. When emitting assembly or machine code, these |
| // virtual address references are converted to refer to the address of the |
| // function jump tables. |
| // |
| //===----------------------------------------------------------------------===// |
| |
| #ifndef LLVM_CODEGEN_MACHINEJUMPTABLEINFO_H |
| #define LLVM_CODEGEN_MACHINEJUMPTABLEINFO_H |
| |
| #include <vector> |
| #include <iosfwd> |
| #include <cassert> |
| |
| namespace llvm { |
| |
| class MachineBasicBlock; |
| class TargetData; |
| |
| /// MachineJumpTableEntry - One jump table in the jump table info. |
| /// |
| struct MachineJumpTableEntry { |
| /// MBBs - The vector of basic blocks from which to create the jump table. |
| std::vector<MachineBasicBlock*> MBBs; |
| |
| explicit MachineJumpTableEntry(const std::vector<MachineBasicBlock*> &M) |
| : MBBs(M) {} |
| }; |
| |
| class MachineJumpTableInfo { |
| unsigned EntrySize; |
| unsigned Alignment; |
| std::vector<MachineJumpTableEntry> JumpTables; |
| public: |
| MachineJumpTableInfo(unsigned Size, unsigned Align) |
| : EntrySize(Size), Alignment(Align) {} |
| |
| /// getJumpTableIndex - Create a new jump table or return an existing one. |
| /// |
| unsigned getJumpTableIndex(const std::vector<MachineBasicBlock*> &DestBBs); |
| |
| /// isEmpty - Return true if there are no jump tables. |
| /// |
| bool isEmpty() const { return JumpTables.empty(); } |
| |
| const std::vector<MachineJumpTableEntry> &getJumpTables() const { |
| return JumpTables; |
| } |
| |
| /// RemoveJumpTable - Mark the specific index as being dead. This will cause |
| /// it to not be emitted. |
| void RemoveJumpTable(unsigned Idx) { |
| JumpTables[Idx].MBBs.clear(); |
| } |
| |
| /// ReplaceMBBInJumpTables - If Old is the target of any jump tables, update |
| /// the jump tables to branch to New instead. |
| bool ReplaceMBBInJumpTables(MachineBasicBlock *Old, MachineBasicBlock *New) { |
| assert(Old != New && "Not making a change?"); |
| bool MadeChange = false; |
| for (unsigned i = 0, e = JumpTables.size(); i != e; ++i) { |
| MachineJumpTableEntry &JTE = JumpTables[i]; |
| for (unsigned j = 0, e = JTE.MBBs.size(); j != e; ++j) |
| if (JTE.MBBs[j] == Old) { |
| JTE.MBBs[j] = New; |
| MadeChange = true; |
| } |
| } |
| return MadeChange; |
| } |
| |
| /// getEntrySize - Returns the size of an individual field in a jump table. |
| /// |
| unsigned getEntrySize() const { return EntrySize; } |
| |
| /// getAlignment - returns the target's preferred alignment for jump tables |
| unsigned getAlignment() const { return Alignment; } |
| |
| /// print - Used by the MachineFunction printer to print information about |
| /// jump tables. 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; |
| }; |
| |
| } // End llvm namespace |
| |
| #endif |