1 //===-- llvm/CodeGen/MachineBasicBlock.h ------------------------*- C++ -*-===//
3 // The LLVM Compiler Infrastructure
5 // This file is distributed under the University of Illinois Open Source
6 // 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/Support/Streams.h"
24 class MachineFunction;
27 struct ilist_traits<MachineInstr> : public ilist_default_traits<MachineInstr> {
29 mutable MachineInstr Sentinel;
31 // this is only set by the MachineBasicBlock owning the LiveList
32 friend class MachineBasicBlock;
33 MachineBasicBlock* Parent;
36 MachineInstr *createSentinel() const { return &Sentinel; }
37 void destroySentinel(MachineInstr *) const {}
39 void addNodeToList(MachineInstr* N);
40 void removeNodeFromList(MachineInstr* N);
41 void transferNodesFromList(ilist_traits &SrcTraits,
42 ilist_iterator<MachineInstr> first,
43 ilist_iterator<MachineInstr> last);
44 void deleteNode(MachineInstr *N);
46 void createNode(const MachineInstr &);
49 class MachineBasicBlock : public ilist_node<MachineBasicBlock> {
50 typedef ilist<MachineInstr> Instructions;
54 MachineFunction *xParent;
56 /// Predecessors/Successors - Keep track of the predecessor / successor
58 std::vector<MachineBasicBlock *> Predecessors;
59 std::vector<MachineBasicBlock *> Successors;
61 /// LiveIns - Keep track of the physical registers that are livein of
63 std::vector<unsigned> LiveIns;
65 /// Alignment - Alignment of the basic block. Zero if the basic block does
66 /// not need to be aligned.
69 /// IsLandingPad - Indicate that this basic block is entered via an
70 /// exception handler.
73 // Intrusive list support
74 friend struct ilist_sentinel_traits<MachineBasicBlock>;
75 MachineBasicBlock() {}
77 explicit MachineBasicBlock(MachineFunction &mf, const BasicBlock *bb);
81 // MachineBasicBlocks are allocated and owned by MachineFunction.
82 friend class MachineFunction;
85 /// getBasicBlock - Return the LLVM basic block that this instance
86 /// corresponded to originally.
88 const BasicBlock *getBasicBlock() const { return BB; }
90 /// getParent - Return the MachineFunction containing this basic block.
92 const MachineFunction *getParent() const { return xParent; }
93 MachineFunction *getParent() { return xParent; }
95 typedef Instructions::iterator iterator;
96 typedef Instructions::const_iterator const_iterator;
97 typedef std::reverse_iterator<const_iterator> const_reverse_iterator;
98 typedef std::reverse_iterator<iterator> reverse_iterator;
100 unsigned size() const { return (unsigned)Insts.size(); }
101 bool empty() const { return Insts.empty(); }
103 MachineInstr& front() { return Insts.front(); }
104 MachineInstr& back() { return Insts.back(); }
105 const MachineInstr& front() const { return Insts.front(); }
106 const MachineInstr& back() const { return Insts.back(); }
108 iterator begin() { return Insts.begin(); }
109 const_iterator begin() const { return Insts.begin(); }
110 iterator end() { return Insts.end(); }
111 const_iterator end() const { return Insts.end(); }
112 reverse_iterator rbegin() { return Insts.rbegin(); }
113 const_reverse_iterator rbegin() const { return Insts.rbegin(); }
114 reverse_iterator rend () { return Insts.rend(); }
115 const_reverse_iterator rend () const { return Insts.rend(); }
117 // Machine-CFG iterators
118 typedef std::vector<MachineBasicBlock *>::iterator pred_iterator;
119 typedef std::vector<MachineBasicBlock *>::const_iterator const_pred_iterator;
120 typedef std::vector<MachineBasicBlock *>::iterator succ_iterator;
121 typedef std::vector<MachineBasicBlock *>::const_iterator const_succ_iterator;
122 typedef std::vector<MachineBasicBlock *>::reverse_iterator
123 pred_reverse_iterator;
124 typedef std::vector<MachineBasicBlock *>::const_reverse_iterator
125 const_pred_reverse_iterator;
126 typedef std::vector<MachineBasicBlock *>::reverse_iterator
127 succ_reverse_iterator;
128 typedef std::vector<MachineBasicBlock *>::const_reverse_iterator
129 const_succ_reverse_iterator;
131 pred_iterator pred_begin() { return Predecessors.begin(); }
132 const_pred_iterator pred_begin() const { return Predecessors.begin(); }
133 pred_iterator pred_end() { return Predecessors.end(); }
134 const_pred_iterator pred_end() const { return Predecessors.end(); }
135 pred_reverse_iterator pred_rbegin()
136 { return Predecessors.rbegin();}
137 const_pred_reverse_iterator pred_rbegin() const
138 { return Predecessors.rbegin();}
139 pred_reverse_iterator pred_rend()
140 { return Predecessors.rend(); }
141 const_pred_reverse_iterator pred_rend() const
142 { return Predecessors.rend(); }
143 unsigned pred_size() const {
144 return (unsigned)Predecessors.size();
146 bool pred_empty() const { return Predecessors.empty(); }
147 succ_iterator succ_begin() { return Successors.begin(); }
148 const_succ_iterator succ_begin() const { return Successors.begin(); }
149 succ_iterator succ_end() { return Successors.end(); }
150 const_succ_iterator succ_end() const { return Successors.end(); }
151 succ_reverse_iterator succ_rbegin()
152 { return Successors.rbegin(); }
153 const_succ_reverse_iterator succ_rbegin() const
154 { return Successors.rbegin(); }
155 succ_reverse_iterator succ_rend()
156 { return Successors.rend(); }
157 const_succ_reverse_iterator succ_rend() const
158 { return Successors.rend(); }
159 unsigned succ_size() const {
160 return (unsigned)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 /// isLiveIn - Return true if the specified register is in the live in set.
176 bool isLiveIn(unsigned Reg) const;
178 // Iteration support for live in sets. These sets are kept in sorted
179 // order by their register number.
180 typedef std::vector<unsigned>::iterator livein_iterator;
181 typedef std::vector<unsigned>::const_iterator const_livein_iterator;
182 livein_iterator livein_begin() { return LiveIns.begin(); }
183 const_livein_iterator livein_begin() const { return LiveIns.begin(); }
184 livein_iterator livein_end() { return LiveIns.end(); }
185 const_livein_iterator livein_end() const { return LiveIns.end(); }
186 bool livein_empty() const { return LiveIns.empty(); }
188 /// getAlignment - Return alignment of the basic block.
190 unsigned getAlignment() const { return Alignment; }
192 /// setAlignment - Set alignment of the basic block.
194 void setAlignment(unsigned Align) { Alignment = Align; }
196 /// isLandingPad - Returns true if the block is a landing pad. That is
197 /// this basic block is entered via an exception handler.
198 bool isLandingPad() const { return IsLandingPad; }
200 /// setIsLandingPad - Indicates the block is a landing pad. That is
201 /// this basic block is entered via an exception handler.
202 void setIsLandingPad() { IsLandingPad = true; }
204 // Code Layout methods.
206 /// moveBefore/moveAfter - move 'this' block before or after the specified
207 /// block. This only moves the block, it does not modify the CFG or adjust
208 /// potential fall-throughs at the end of the block.
209 void moveBefore(MachineBasicBlock *NewAfter);
210 void moveAfter(MachineBasicBlock *NewBefore);
212 // Machine-CFG mutators
214 /// addSuccessor - Add succ as a successor of this MachineBasicBlock.
215 /// The Predecessors list of succ is automatically updated.
217 void addSuccessor(MachineBasicBlock *succ);
219 /// removeSuccessor - Remove successor from the successors list of this
220 /// MachineBasicBlock. The Predecessors list of succ is automatically updated.
222 void removeSuccessor(MachineBasicBlock *succ);
224 /// removeSuccessor - Remove specified successor from the successors list of
225 /// this MachineBasicBlock. The Predecessors list of succ is automatically
226 /// updated. Return the iterator to the element after the one removed.
228 succ_iterator removeSuccessor(succ_iterator I);
230 /// transferSuccessors - Transfers all the successors from MBB to this
231 /// machine basic block (i.e., copies all the successors fromMBB and
232 /// remove all the successors fromBB).
233 void transferSuccessors(MachineBasicBlock *fromMBB);
235 /// isSuccessor - Return true if the specified MBB is a successor of this
237 bool isSuccessor(MachineBasicBlock *MBB) const;
239 /// isLayoutSuccessor - Return true if the specified MBB will be emitted
240 /// immediately after this block, such that if this block exits by
241 /// falling through, control will transfer to the specified MBB. Note
242 /// that MBB need not be a successor at all, for example if this block
243 /// ends with an unconditional branch to some other block.
244 bool isLayoutSuccessor(MachineBasicBlock *MBB) const;
246 /// getFirstTerminator - returns an iterator to the first terminator
247 /// instruction of this basic block. If a terminator does not exist,
249 iterator getFirstTerminator();
251 void pop_front() { Insts.pop_front(); }
252 void pop_back() { Insts.pop_back(); }
253 void push_back(MachineInstr *MI) { Insts.push_back(MI); }
254 template<typename IT>
255 void insert(iterator I, IT S, IT E) { Insts.insert(I, S, E); }
256 iterator insert(iterator I, MachineInstr *M) { return Insts.insert(I, M); }
258 // erase - Remove the specified element or range from the instruction list.
259 // These functions delete any instructions removed.
261 iterator erase(iterator I) { return Insts.erase(I); }
262 iterator erase(iterator I, iterator E) { return Insts.erase(I, E); }
263 MachineInstr *remove(MachineInstr *I) { return Insts.remove(I); }
264 void clear() { Insts.clear(); }
266 /// splice - Take a block of instructions from MBB 'Other' in the range [From,
267 /// To), and insert them into this MBB right before 'where'.
268 void splice(iterator where, MachineBasicBlock *Other, iterator From,
270 Insts.splice(where, Other->Insts, From, To);
273 /// removeFromParent - This method unlinks 'this' from the containing
274 /// function, and returns it, but does not delete it.
275 MachineBasicBlock *removeFromParent();
277 /// eraseFromParent - This method unlinks 'this' from the containing
278 /// function and deletes it.
279 void eraseFromParent();
281 /// ReplaceUsesOfBlockWith - Given a machine basic block that branched to
282 /// 'Old', change the code and CFG so that it branches to 'New' instead.
283 void ReplaceUsesOfBlockWith(MachineBasicBlock *Old, MachineBasicBlock *New);
285 /// CorrectExtraCFGEdges - Various pieces of code can cause excess edges in
286 /// the CFG to be inserted. If we have proven that MBB can only branch to
287 /// DestA and DestB, remove any other MBB successors from the CFG. DestA and
288 /// DestB can be null. Besides DestA and DestB, retain other edges leading
289 /// to LandingPads (currently there can be only one; we don't check or require
290 /// that here). Note it is possible that DestA and/or DestB are LandingPads.
291 bool CorrectExtraCFGEdges(MachineBasicBlock *DestA,
292 MachineBasicBlock *DestB,
295 // Debugging methods.
297 void print(std::ostream &OS) const;
298 void print(std::ostream *OS) const { if (OS) print(*OS); }
300 /// getNumber - MachineBasicBlocks are uniquely numbered at the function
301 /// level, unless they're not in a MachineFunction yet, in which case this
304 int getNumber() const { return Number; }
305 void setNumber(int N) { Number = N; }
307 private: // Methods used to maintain doubly linked list of blocks...
308 friend struct ilist_traits<MachineBasicBlock>;
310 // Machine-CFG mutators
312 /// addPredecessor - Remove pred as a predecessor of this MachineBasicBlock.
313 /// Don't do this unless you know what you're doing, because it doesn't
314 /// update pred's successors list. Use pred->addSuccessor instead.
316 void addPredecessor(MachineBasicBlock *pred);
318 /// removePredecessor - Remove pred as a predecessor of this
319 /// MachineBasicBlock. Don't do this unless you know what you're
320 /// doing, because it doesn't update pred's successors list. Use
321 /// pred->removeSuccessor instead.
323 void removePredecessor(MachineBasicBlock *pred);
326 std::ostream& operator<<(std::ostream &OS, const MachineBasicBlock &MBB);
328 //===--------------------------------------------------------------------===//
329 // GraphTraits specializations for machine basic block graphs (machine-CFGs)
330 //===--------------------------------------------------------------------===//
332 // Provide specializations of GraphTraits to be able to treat a
333 // MachineFunction as a graph of MachineBasicBlocks...
336 template <> struct GraphTraits<MachineBasicBlock *> {
337 typedef MachineBasicBlock NodeType;
338 typedef MachineBasicBlock::succ_iterator ChildIteratorType;
340 static NodeType *getEntryNode(MachineBasicBlock *BB) { return BB; }
341 static inline ChildIteratorType child_begin(NodeType *N) {
342 return N->succ_begin();
344 static inline ChildIteratorType child_end(NodeType *N) {
345 return N->succ_end();
349 template <> struct GraphTraits<const MachineBasicBlock *> {
350 typedef const MachineBasicBlock NodeType;
351 typedef MachineBasicBlock::const_succ_iterator ChildIteratorType;
353 static NodeType *getEntryNode(const MachineBasicBlock *BB) { return BB; }
354 static inline ChildIteratorType child_begin(NodeType *N) {
355 return N->succ_begin();
357 static inline ChildIteratorType child_end(NodeType *N) {
358 return N->succ_end();
362 // Provide specializations of GraphTraits to be able to treat a
363 // MachineFunction as a graph of MachineBasicBlocks... and to walk it
364 // in inverse order. Inverse order for a function is considered
365 // to be when traversing the predecessor edges of a MBB
366 // instead of the successor edges.
368 template <> struct GraphTraits<Inverse<MachineBasicBlock*> > {
369 typedef MachineBasicBlock NodeType;
370 typedef MachineBasicBlock::pred_iterator ChildIteratorType;
371 static NodeType *getEntryNode(Inverse<MachineBasicBlock *> G) {
374 static inline ChildIteratorType child_begin(NodeType *N) {
375 return N->pred_begin();
377 static inline ChildIteratorType child_end(NodeType *N) {
378 return N->pred_end();
382 template <> struct GraphTraits<Inverse<const MachineBasicBlock*> > {
383 typedef const MachineBasicBlock NodeType;
384 typedef MachineBasicBlock::const_pred_iterator ChildIteratorType;
385 static NodeType *getEntryNode(Inverse<const MachineBasicBlock*> G) {
388 static inline ChildIteratorType child_begin(NodeType *N) {
389 return N->pred_begin();
391 static inline ChildIteratorType child_end(NodeType *N) {
392 return N->pred_end();
396 } // End llvm namespace