1 //===-- CodeGen/MachineJumpTableInfo.h - Abstract Jump Tables --*- C++ -*-===//
3 // The LLVM Compiler Infrastructure
5 // This file was developed by Nate Begeman and is distributed under the
6 // University of Illinois Open Source License. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
10 // The MachineJumpTableInfo class keeps track of jump tables referenced by
11 // lowered switch instructions in the MachineFunction.
13 // Instructions reference the address of these jump tables through the use of
14 // MO_JumpTableIndex values. When emitting assembly or machine code, these
15 // virtual address references are converted to refer to the address of the
16 // function jump tables.
18 //===----------------------------------------------------------------------===//
20 #ifndef LLVM_CODEGEN_MACHINEJUMPTABLEINFO_H
21 #define LLVM_CODEGEN_MACHINEJUMPTABLEINFO_H
28 class MachineBasicBlock;
31 /// MachineJumpTableEntry - One jump table in the jump table info.
33 struct MachineJumpTableEntry {
34 /// MBBs - The vector of basic blocks from which to create the jump table.
35 std::vector<MachineBasicBlock*> MBBs;
37 MachineJumpTableEntry(const std::vector<MachineBasicBlock*> &M) : MBBs(M) {}
40 class MachineJumpTableInfo {
43 std::vector<MachineJumpTableEntry> JumpTables;
45 MachineJumpTableInfo(unsigned Size, unsigned Align)
46 : EntrySize(Size), Alignment(Align) {}
48 /// getJumpTableIndex - Create a new jump table or return an existing one.
50 unsigned getJumpTableIndex(const std::vector<MachineBasicBlock*> &DestBBs);
52 /// isEmpty - Return true if there are no jump tables.
54 bool isEmpty() const { return JumpTables.empty(); }
56 const std::vector<MachineJumpTableEntry> &getJumpTables() const {
60 /// RemoveJumpTable - Mark the specific index as being dead. This will cause
61 /// it to not be emitted.
62 void RemoveJumpTable(unsigned Idx) {
63 JumpTables[Idx].MBBs.clear();
66 /// ReplaceMBBInJumpTables - If Old is the target of any jump tables, update
67 /// the jump tables to branch to New instead.
68 bool ReplaceMBBInJumpTables(MachineBasicBlock *Old, MachineBasicBlock *New) {
69 assert(Old != New && "Not making a change?");
70 bool MadeChange = false;
71 for (unsigned i = 0, e = JumpTables.size(); i != e; ++i) {
72 MachineJumpTableEntry &JTE = JumpTables[i];
73 for (unsigned j = 0, e = JTE.MBBs.size(); j != e; ++j)
74 if (JTE.MBBs[j] == Old) {
82 /// getEntrySize - Returns the size of an individual field in a jump table.
84 unsigned getEntrySize() const { return EntrySize; }
86 /// getAlignment - returns the target's preferred alignment for jump tables
87 unsigned getAlignment() const { return Alignment; }
89 /// print - Used by the MachineFunction printer to print information about
90 /// jump tables. Implemented in MachineFunction.cpp
92 void print(std::ostream &OS) const;
94 /// dump - Call print(std::cerr) to be called from the debugger.
99 } // End llvm namespace