1 //===-- llvm/CodeGen/MachineBasicBlock.h ------------------------*- C++ -*-===//
3 // The LLVM Compiler Infrastructure
5 // This file was developed by the LLVM research group and is distributed under
6 // the University of Illinois Open Source License. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
10 // Collect the sequence of machine instructions for a basic block.
12 //===----------------------------------------------------------------------===//
14 #ifndef LLVM_CODEGEN_MACHINEBASICBLOCK_H
15 #define LLVM_CODEGEN_MACHINEBASICBLOCK_H
17 #include "llvm/CodeGen/MachineInstr.h"
18 #include "llvm/ADT/GraphTraits.h"
19 #include "llvm/ADT/ilist"
20 #include "llvm/Support/Streams.h"
23 class MachineFunction;
27 struct ilist_traits<MachineInstr> {
29 // this is only set by the MachineBasicBlock owning the ilist
30 friend class MachineBasicBlock;
31 MachineBasicBlock* parent;
34 ilist_traits<MachineInstr>() : parent(0) { }
36 static MachineInstr* getPrev(MachineInstr* N) { return N->prev; }
37 static MachineInstr* getNext(MachineInstr* N) { return N->next; }
39 static const MachineInstr*
40 getPrev(const MachineInstr* N) { return N->prev; }
42 static const MachineInstr*
43 getNext(const MachineInstr* N) { return N->next; }
45 static void setPrev(MachineInstr* N, MachineInstr* prev) { N->prev = prev; }
46 static void setNext(MachineInstr* N, MachineInstr* next) { N->next = next; }
48 static MachineInstr* createSentinel();
49 static void destroySentinel(MachineInstr *MI) { delete MI; }
50 void addNodeToList(MachineInstr* N);
51 void removeNodeFromList(MachineInstr* N);
52 void transferNodesFromList(
53 iplist<MachineInstr, ilist_traits<MachineInstr> >& toList,
54 ilist_iterator<MachineInstr> first,
55 ilist_iterator<MachineInstr> last);
60 class MachineBasicBlock {
61 typedef ilist<MachineInstr> Instructions;
63 MachineBasicBlock *Prev, *Next;
66 MachineFunction *Parent;
68 /// Predecessors/Successors - Keep track of the predecessor / successor
70 std::vector<MachineBasicBlock *> Predecessors;
71 std::vector<MachineBasicBlock *> Successors;
73 /// LiveIns - Keep track of the physical registers that are livein of
75 std::vector<unsigned> LiveIns;
77 /// IsLandingPad - Indicate that this basic block is entered via an
78 /// exception handler.
82 explicit MachineBasicBlock(const BasicBlock *bb = 0) : Prev(0), Next(0),
91 /// getBasicBlock - Return the LLVM basic block that this instance
92 /// corresponded to originally.
94 const BasicBlock *getBasicBlock() const { return BB; }
96 /// getParent - Return the MachineFunction containing this basic block.
98 const MachineFunction *getParent() const { return Parent; }
99 MachineFunction *getParent() { return Parent; }
101 typedef ilist<MachineInstr>::iterator iterator;
102 typedef ilist<MachineInstr>::const_iterator const_iterator;
103 typedef std::reverse_iterator<const_iterator> const_reverse_iterator;
104 typedef std::reverse_iterator<iterator> reverse_iterator;
106 unsigned size() const { return Insts.size(); }
107 bool empty() const { return Insts.empty(); }
109 MachineInstr& front() { return Insts.front(); }
110 MachineInstr& back() { return Insts.back(); }
112 iterator begin() { return Insts.begin(); }
113 const_iterator begin() const { return Insts.begin(); }
114 iterator end() { return Insts.end(); }
115 const_iterator end() const { return Insts.end(); }
116 reverse_iterator rbegin() { return Insts.rbegin(); }
117 const_reverse_iterator rbegin() const { return Insts.rbegin(); }
118 reverse_iterator rend () { return Insts.rend(); }
119 const_reverse_iterator rend () const { return Insts.rend(); }
121 // Machine-CFG iterators
122 typedef std::vector<MachineBasicBlock *>::iterator pred_iterator;
123 typedef std::vector<MachineBasicBlock *>::const_iterator const_pred_iterator;
124 typedef std::vector<MachineBasicBlock *>::iterator succ_iterator;
125 typedef std::vector<MachineBasicBlock *>::const_iterator const_succ_iterator;
126 typedef std::vector<MachineBasicBlock *>::reverse_iterator
127 pred_reverse_iterator;
128 typedef std::vector<MachineBasicBlock *>::const_reverse_iterator
129 const_pred_reverse_iterator;
130 typedef std::vector<MachineBasicBlock *>::reverse_iterator
131 succ_reverse_iterator;
132 typedef std::vector<MachineBasicBlock *>::const_reverse_iterator
133 const_succ_reverse_iterator;
135 pred_iterator pred_begin() { return Predecessors.begin(); }
136 const_pred_iterator pred_begin() const { return Predecessors.begin(); }
137 pred_iterator pred_end() { return Predecessors.end(); }
138 const_pred_iterator pred_end() const { return Predecessors.end(); }
139 pred_reverse_iterator pred_rbegin()
140 { return Predecessors.rbegin();}
141 const_pred_reverse_iterator pred_rbegin() const
142 { return Predecessors.rbegin();}
143 pred_reverse_iterator pred_rend()
144 { return Predecessors.rend(); }
145 const_pred_reverse_iterator pred_rend() const
146 { return Predecessors.rend(); }
147 unsigned pred_size() const { return Predecessors.size(); }
148 bool pred_empty() const { return Predecessors.empty(); }
149 succ_iterator succ_begin() { return Successors.begin(); }
150 const_succ_iterator succ_begin() const { return Successors.begin(); }
151 succ_iterator succ_end() { return Successors.end(); }
152 const_succ_iterator succ_end() const { return Successors.end(); }
153 succ_reverse_iterator succ_rbegin()
154 { return Successors.rbegin(); }
155 const_succ_reverse_iterator succ_rbegin() const
156 { return Successors.rbegin(); }
157 succ_reverse_iterator succ_rend()
158 { return Successors.rend(); }
159 const_succ_reverse_iterator succ_rend() const
160 { return Successors.rend(); }
161 unsigned succ_size() const { return Successors.size(); }
162 bool succ_empty() const { return Successors.empty(); }
164 // LiveIn management methods.
166 /// addLiveIn - Add the specified register as a live in. Note that it
167 /// is an error to add the same register to the same set more than once.
168 void addLiveIn(unsigned Reg) { LiveIns.push_back(Reg); }
170 /// removeLiveIn - Remove the specified register from the live in set.
172 void removeLiveIn(unsigned Reg);
174 // Iteration support for live in sets. These sets are kept in sorted
175 // order by their register number.
176 typedef std::vector<unsigned>::iterator livein_iterator;
177 typedef std::vector<unsigned>::const_iterator const_livein_iterator;
178 livein_iterator livein_begin() { return LiveIns.begin(); }
179 const_livein_iterator livein_begin() const { return LiveIns.begin(); }
180 livein_iterator livein_end() { return LiveIns.end(); }
181 const_livein_iterator livein_end() const { return LiveIns.end(); }
182 bool livein_empty() const { return LiveIns.empty(); }
184 /// isLandingPad - Returns true if the block is a landing pad. That is
185 /// this basic block is entered via an exception handler.
186 bool isLandingPad() const { return IsLandingPad; }
188 /// setIsLandingPad - Indicates the block is a landing pad. That is
189 /// this basic block is entered via an exception handler.
190 void setIsLandingPad() { IsLandingPad = true; }
192 // Code Layout methods.
194 /// moveBefore/moveAfter - move 'this' block before or after the specified
195 /// block. This only moves the block, it does not modify the CFG or adjust
196 /// potential fall-throughs at the end of the block.
197 void moveBefore(MachineBasicBlock *NewAfter);
198 void moveAfter(MachineBasicBlock *NewBefore);
200 // Machine-CFG mutators
202 /// addSuccessor - Add succ as a successor of this MachineBasicBlock.
203 /// The Predecessors list of succ is automatically updated.
205 void addSuccessor(MachineBasicBlock *succ);
207 /// removeSuccessor - Remove successor from the successors list of this
208 /// MachineBasicBlock. The Predecessors list of succ is automatically updated.
210 void removeSuccessor(MachineBasicBlock *succ);
212 /// removeSuccessor - Remove specified successor from the successors list of
213 /// this MachineBasicBlock. The Predecessors list of succ is automatically
214 /// updated. Return the iterator to the element after the one removed.
216 succ_iterator removeSuccessor(succ_iterator I);
218 /// isSuccessor - Return true if the specified MBB is a successor of this
220 bool isSuccessor(MachineBasicBlock *MBB) const;
222 /// getFirstTerminator - returns an iterator to the first terminator
223 /// instruction of this basic block. If a terminator does not exist,
225 iterator getFirstTerminator();
227 void pop_front() { Insts.pop_front(); }
228 void pop_back() { Insts.pop_back(); }
229 void push_back(MachineInstr *MI) { Insts.push_back(MI); }
230 template<typename IT>
231 void insert(iterator I, IT S, IT E) { Insts.insert(I, S, E); }
232 iterator insert(iterator I, MachineInstr *M) { return Insts.insert(I, M); }
234 // erase - Remove the specified element or range from the instruction list.
235 // These functions delete any instructions removed.
237 iterator erase(iterator I) { return Insts.erase(I); }
238 iterator erase(iterator I, iterator E) { return Insts.erase(I, E); }
239 MachineInstr *remove(MachineInstr *I) { return Insts.remove(I); }
240 void clear() { Insts.clear(); }
242 /// splice - Take a block of instructions from MBB 'Other' in the range [From,
243 /// To), and insert them into this MBB right before 'where'.
244 void splice(iterator where, MachineBasicBlock *Other, iterator From,
246 Insts.splice(where, Other->Insts, From, To);
249 /// ReplaceUsesOfBlockWith - Given a machine basic block that branched to
250 /// 'Old', change the code and CFG so that it branches to 'New' instead.
251 void ReplaceUsesOfBlockWith(MachineBasicBlock *Old, MachineBasicBlock *New);
253 /// CorrectExtraCFGEdges - Various pieces of code can cause excess edges in
254 /// the CFG to be inserted. If we have proven that MBB can only branch to
255 /// DestA and DestB, remove any other MBB successors from the CFG. DestA and
256 /// DestB can be null. Besides DestA and DestB, retain other edges leading
257 /// to LandingPads (currently there can be only one; we don't check or require
258 /// that here). Note it is possible that DestA and/or DestB are LandingPads.
259 bool CorrectExtraCFGEdges(MachineBasicBlock *DestA,
260 MachineBasicBlock *DestB,
263 // Debugging methods.
265 void print(std::ostream &OS) const;
266 void print(std::ostream *OS) const { if (OS) print(*OS); }
268 /// getNumber - MachineBasicBlocks are uniquely numbered at the function
269 /// level, unless they're not in a MachineFunction yet, in which case this
272 int getNumber() const { return Number; }
273 void setNumber(int N) { Number = N; }
275 private: // Methods used to maintain doubly linked list of blocks...
276 friend struct ilist_traits<MachineBasicBlock>;
278 MachineBasicBlock *getPrev() const { return Prev; }
279 MachineBasicBlock *getNext() const { return Next; }
280 void setPrev(MachineBasicBlock *P) { Prev = P; }
281 void setNext(MachineBasicBlock *N) { Next = N; }
283 // Machine-CFG mutators
285 /// addPredecessor - Remove pred as a predecessor of this MachineBasicBlock.
286 /// Don't do this unless you know what you're doing, because it doesn't
287 /// update pred's successors list. Use pred->addSuccessor instead.
289 void addPredecessor(MachineBasicBlock *pred);
291 /// removePredecessor - Remove pred as a predecessor of this
292 /// MachineBasicBlock. Don't do this unless you know what you're
293 /// doing, because it doesn't update pred's successors list. Use
294 /// pred->removeSuccessor instead.
296 void removePredecessor(MachineBasicBlock *pred);
299 std::ostream& operator<<(std::ostream &OS, const MachineBasicBlock &MBB);
301 //===--------------------------------------------------------------------===//
302 // GraphTraits specializations for machine basic block graphs (machine-CFGs)
303 //===--------------------------------------------------------------------===//
305 // Provide specializations of GraphTraits to be able to treat a
306 // MachineFunction as a graph of MachineBasicBlocks...
309 template <> struct GraphTraits<MachineBasicBlock *> {
310 typedef MachineBasicBlock NodeType;
311 typedef MachineBasicBlock::succ_iterator ChildIteratorType;
313 static NodeType *getEntryNode(MachineBasicBlock *BB) { return BB; }
314 static inline ChildIteratorType child_begin(NodeType *N) {
315 return N->succ_begin();
317 static inline ChildIteratorType child_end(NodeType *N) {
318 return N->succ_end();
322 template <> struct GraphTraits<const MachineBasicBlock *> {
323 typedef const MachineBasicBlock NodeType;
324 typedef MachineBasicBlock::const_succ_iterator ChildIteratorType;
326 static NodeType *getEntryNode(const MachineBasicBlock *BB) { return BB; }
327 static inline ChildIteratorType child_begin(NodeType *N) {
328 return N->succ_begin();
330 static inline ChildIteratorType child_end(NodeType *N) {
331 return N->succ_end();
335 // Provide specializations of GraphTraits to be able to treat a
336 // MachineFunction as a graph of MachineBasicBlocks... and to walk it
337 // in inverse order. Inverse order for a function is considered
338 // to be when traversing the predecessor edges of a MBB
339 // instead of the successor edges.
341 template <> struct GraphTraits<Inverse<MachineBasicBlock*> > {
342 typedef MachineBasicBlock NodeType;
343 typedef MachineBasicBlock::pred_iterator ChildIteratorType;
344 static NodeType *getEntryNode(Inverse<MachineBasicBlock *> G) {
347 static inline ChildIteratorType child_begin(NodeType *N) {
348 return N->pred_begin();
350 static inline ChildIteratorType child_end(NodeType *N) {
351 return N->pred_end();
355 template <> struct GraphTraits<Inverse<const MachineBasicBlock*> > {
356 typedef const MachineBasicBlock NodeType;
357 typedef MachineBasicBlock::const_pred_iterator ChildIteratorType;
358 static NodeType *getEntryNode(Inverse<const MachineBasicBlock*> G) {
361 static inline ChildIteratorType child_begin(NodeType *N) {
362 return N->pred_begin();
364 static inline ChildIteratorType child_end(NodeType *N) {
365 return N->pred_end();
369 } // End llvm namespace