//===-- 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 <cassert> namespace llvm { class MachineBasicBlock; class TargetData; class raw_ostream; /// 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 { public: /// JTEntryKind - This enum indicates how each entry of the jump table is /// represented and emitted. enum JTEntryKind { /// EK_BlockAddress - Each entry is a plain address of block, e.g.: /// .word LBB123 EK_BlockAddress, /// EK_GPRel32BlockAddress - Each entry is an address of block, encoded /// with a relocation as gp-relative, e.g.: /// .gprel32 LBB123 EK_GPRel32BlockAddress, /// EK_LabelDifference32 - Each entry is the address of the block minus /// the address of the jump table. This is used for PIC jump tables where /// gprel32 is not supported. e.g.: /// .word LBB123 - LJTI1_2 /// If the .set directive is supported, this is emitted as: /// .set L4_5_set_123, LBB123 - LJTI1_2 /// .word L4_5_set_123 EK_LabelDifference32, /// EK_Inline - Jump table entries are emitted inline at their point of /// use. It is the responsibility of the target to emit the entries. EK_Inline, /// EK_Custom32 - Each entry is a 32-bit value that is custom lowered by the /// TargetLowering::LowerCustomJumpTableEntry hook. EK_Custom32 }; private: JTEntryKind EntryKind; std::vector<MachineJumpTableEntry> JumpTables; public: explicit MachineJumpTableInfo(JTEntryKind Kind): EntryKind(Kind) {} JTEntryKind getEntryKind() const { return EntryKind; } /// getEntrySize - Return the size of each entry in the jump table. unsigned getEntrySize(const TargetData &TD) const; /// getEntryAlignment - Return the alignment of each entry in the jump table. unsigned getEntryAlignment(const TargetData &TD) const; /// createJumpTableIndex - Create a new jump table. /// unsigned createJumpTableIndex(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 /// prevent it from being 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); /// ReplaceMBBInJumpTable - If Old is a target of the jump tables, update /// the jump table to branch to New instead. bool ReplaceMBBInJumpTable(unsigned Idx, MachineBasicBlock *Old, MachineBasicBlock *New); /// print - Used by the MachineFunction printer to print information about /// jump tables. Implemented in MachineFunction.cpp /// void print(raw_ostream &OS) const; /// dump - Call to stderr. /// void dump() const; }; } // End llvm namespace #endif