| //===-- CodeGen/MachineJumpTableInfo.h - Abstract Jump Tables --*- C++ -*-===// |
| // |
| // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. |
| // See https://llvm.org/LICENSE.txt for license information. |
| // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception |
| // |
| //===----------------------------------------------------------------------===// |
| // |
| // 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 "llvm/Support/Printable.h" |
| #include <cassert> |
| #include <vector> |
| |
| namespace llvm { |
| |
| class MachineBasicBlock; |
| class DataLayout; |
| 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_GPRel64BlockAddress - Each entry is an address of block, encoded |
| /// with a relocation as gp-relative, e.g.: |
| /// .gpdword LBB123 |
| EK_GPRel64BlockAddress, |
| |
| /// 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 DataLayout &TD) const; |
| /// getEntryAlignment - Return the alignment of each entry in the jump table. |
| unsigned getEntryAlignment(const DataLayout &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; |
| }; |
| |
| |
| /// Prints a jump table entry reference. |
| /// |
| /// The format is: |
| /// %jump-table.5 - a jump table entry with index == 5. |
| /// |
| /// Usage: OS << printJumpTableEntryReference(Idx) << '\n'; |
| Printable printJumpTableEntryReference(unsigned Idx); |
| |
| } // End llvm namespace |
| |
| #endif |