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Diffstat (limited to 'clang-r353983e/include/llvm/CodeGen/MachineJumpTableInfo.h')
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1 files changed, 139 insertions, 0 deletions
diff --git a/clang-r353983e/include/llvm/CodeGen/MachineJumpTableInfo.h b/clang-r353983e/include/llvm/CodeGen/MachineJumpTableInfo.h new file mode 100644 index 00000000..11781145 --- /dev/null +++ b/clang-r353983e/include/llvm/CodeGen/MachineJumpTableInfo.h @@ -0,0 +1,139 @@ +//===-- 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 |
