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(); }
106 iterator begin() { return Insts.begin(); }
107 const_iterator begin() const { return Insts.begin(); }
108 iterator end() { return Insts.end(); }
109 const_iterator end() const { return Insts.end(); }
110 reverse_iterator rbegin() { return Insts.rbegin(); }
111 const_reverse_iterator rbegin() const { return Insts.rbegin(); }
112 reverse_iterator rend () { return Insts.rend(); }
113 const_reverse_iterator rend () const { return Insts.rend(); }
115 // Machine-CFG iterators
116 typedef std::vector<MachineBasicBlock *>::iterator pred_iterator;
117 typedef std::vector<MachineBasicBlock *>::const_iterator const_pred_iterator;
118 typedef std::vector<MachineBasicBlock *>::iterator succ_iterator;
119 typedef std::vector<MachineBasicBlock *>::const_iterator const_succ_iterator;
120 typedef std::vector<MachineBasicBlock *>::reverse_iterator
121 pred_reverse_iterator;
122 typedef std::vector<MachineBasicBlock *>::const_reverse_iterator
123 const_pred_reverse_iterator;
124 typedef std::vector<MachineBasicBlock *>::reverse_iterator
125 succ_reverse_iterator;
126 typedef std::vector<MachineBasicBlock *>::const_reverse_iterator
127 const_succ_reverse_iterator;
129 pred_iterator pred_begin() { return Predecessors.begin(); }
130 const_pred_iterator pred_begin() const { return Predecessors.begin(); }
131 pred_iterator pred_end() { return Predecessors.end(); }
132 const_pred_iterator pred_end() const { return Predecessors.end(); }
133 pred_reverse_iterator pred_rbegin()
134 { return Predecessors.rbegin();}
135 const_pred_reverse_iterator pred_rbegin() const
136 { return Predecessors.rbegin();}
137 pred_reverse_iterator pred_rend()
138 { return Predecessors.rend(); }
139 const_pred_reverse_iterator pred_rend() const
140 { return Predecessors.rend(); }
141 unsigned pred_size() const {
142 return (unsigned)Predecessors.size();
144 bool pred_empty() const { return Predecessors.empty(); }
145 succ_iterator succ_begin() { return Successors.begin(); }
146 const_succ_iterator succ_begin() const { return Successors.begin(); }
147 succ_iterator succ_end() { return Successors.end(); }
148 const_succ_iterator succ_end() const { return Successors.end(); }
149 succ_reverse_iterator succ_rbegin()
150 { return Successors.rbegin(); }
151 const_succ_reverse_iterator succ_rbegin() const
152 { return Successors.rbegin(); }
153 succ_reverse_iterator succ_rend()
154 { return Successors.rend(); }
155 const_succ_reverse_iterator succ_rend() const
156 { return Successors.rend(); }
157 unsigned succ_size() const {
158 return (unsigned)Successors.size();
160 bool succ_empty() const { return Successors.empty(); }
162 // LiveIn management methods.
164 /// addLiveIn - Add the specified register as a live in. Note that it
165 /// is an error to add the same register to the same set more than once.
166 void addLiveIn(unsigned Reg) { LiveIns.push_back(Reg); }
168 /// removeLiveIn - Remove the specified register from the live in set.
170 void removeLiveIn(unsigned Reg);
172 /// isLiveIn - Return true if the specified register is in the live in set.
174 bool isLiveIn(unsigned Reg) const;
176 // Iteration support for live in sets. These sets are kept in sorted
177 // order by their register number.
178 typedef std::vector<unsigned>::iterator livein_iterator;
179 typedef std::vector<unsigned>::const_iterator const_livein_iterator;
180 livein_iterator livein_begin() { return LiveIns.begin(); }
181 const_livein_iterator livein_begin() const { return LiveIns.begin(); }
182 livein_iterator livein_end() { return LiveIns.end(); }
183 const_livein_iterator livein_end() const { return LiveIns.end(); }
184 bool livein_empty() const { return LiveIns.empty(); }
186 /// getAlignment - Return alignment of the basic block.
188 unsigned getAlignment() const { return Alignment; }
190 /// setAlignment - Set alignment of the basic block.
192 void setAlignment(unsigned Align) { Alignment = Align; }
194 /// isLandingPad - Returns true if the block is a landing pad. That is
195 /// this basic block is entered via an exception handler.
196 bool isLandingPad() const { return IsLandingPad; }
198 /// setIsLandingPad - Indicates the block is a landing pad. That is
199 /// this basic block is entered via an exception handler.
200 void setIsLandingPad() { IsLandingPad = true; }
202 // Code Layout methods.
204 /// moveBefore/moveAfter - move 'this' block before or after the specified
205 /// block. This only moves the block, it does not modify the CFG or adjust
206 /// potential fall-throughs at the end of the block.
207 void moveBefore(MachineBasicBlock *NewAfter);
208 void moveAfter(MachineBasicBlock *NewBefore);
210 // Machine-CFG mutators
212 /// addSuccessor - Add succ as a successor of this MachineBasicBlock.
213 /// The Predecessors list of succ is automatically updated.
215 void addSuccessor(MachineBasicBlock *succ);
217 /// removeSuccessor - Remove successor from the successors list of this
218 /// MachineBasicBlock. The Predecessors list of succ is automatically updated.
220 void removeSuccessor(MachineBasicBlock *succ);
222 /// removeSuccessor - Remove specified successor from the successors list of
223 /// this MachineBasicBlock. The Predecessors list of succ is automatically
224 /// updated. Return the iterator to the element after the one removed.
226 succ_iterator removeSuccessor(succ_iterator I);
228 /// transferSuccessors - Transfers all the successors from MBB to this
229 /// machine basic block (i.e., copies all the successors fromMBB and
230 /// remove all the successors fromBB).
231 void transferSuccessors(MachineBasicBlock *fromMBB);
233 /// isSuccessor - Return true if the specified MBB is a successor of this
235 bool isSuccessor(MachineBasicBlock *MBB) const;
237 /// isLayoutSuccessor - Return true if the specified MBB will be emitted
238 /// immediately after this block, such that if this block exits by
239 /// falling through, control will transfer to the specified MBB. Note
240 /// that MBB need not be a successor at all, for example if this block
241 /// ends with an unconditional branch to some other block.
242 bool isLayoutSuccessor(MachineBasicBlock *MBB) const;
244 /// getFirstTerminator - returns an iterator to the first terminator
245 /// instruction of this basic block. If a terminator does not exist,
247 iterator getFirstTerminator();
249 void pop_front() { Insts.pop_front(); }
250 void pop_back() { Insts.pop_back(); }
251 void push_back(MachineInstr *MI) { Insts.push_back(MI); }
252 template<typename IT>
253 void insert(iterator I, IT S, IT E) { Insts.insert(I, S, E); }
254 iterator insert(iterator I, MachineInstr *M) { return Insts.insert(I, M); }
256 // erase - Remove the specified element or range from the instruction list.
257 // These functions delete any instructions removed.
259 iterator erase(iterator I) { return Insts.erase(I); }
260 iterator erase(iterator I, iterator E) { return Insts.erase(I, E); }
261 MachineInstr *remove(MachineInstr *I) { return Insts.remove(I); }
262 void clear() { Insts.clear(); }
264 /// splice - Take a block of instructions from MBB 'Other' in the range [From,
265 /// To), and insert them into this MBB right before 'where'.
266 void splice(iterator where, MachineBasicBlock *Other, iterator From,
268 Insts.splice(where, Other->Insts, From, To);
271 /// removeFromParent - This method unlinks 'this' from the containing
272 /// function, and returns it, but does not delete it.
273 MachineBasicBlock *removeFromParent();
275 /// eraseFromParent - This method unlinks 'this' from the containing
276 /// function and deletes it.
277 void eraseFromParent();
279 /// ReplaceUsesOfBlockWith - Given a machine basic block that branched to
280 /// 'Old', change the code and CFG so that it branches to 'New' instead.
281 void ReplaceUsesOfBlockWith(MachineBasicBlock *Old, MachineBasicBlock *New);
283 /// CorrectExtraCFGEdges - Various pieces of code can cause excess edges in
284 /// the CFG to be inserted. If we have proven that MBB can only branch to
285 /// DestA and DestB, remove any other MBB successors from the CFG. DestA and
286 /// DestB can be null. Besides DestA and DestB, retain other edges leading
287 /// to LandingPads (currently there can be only one; we don't check or require
288 /// that here). Note it is possible that DestA and/or DestB are LandingPads.
289 bool CorrectExtraCFGEdges(MachineBasicBlock *DestA,
290 MachineBasicBlock *DestB,
293 // Debugging methods.
295 void print(std::ostream &OS) const;
296 void print(std::ostream *OS) const { if (OS) print(*OS); }
298 /// getNumber - MachineBasicBlocks are uniquely numbered at the function
299 /// level, unless they're not in a MachineFunction yet, in which case this
302 int getNumber() const { return Number; }
303 void setNumber(int N) { Number = N; }
305 private: // Methods used to maintain doubly linked list of blocks...
306 friend struct ilist_traits<MachineBasicBlock>;
308 // Machine-CFG mutators
310 /// addPredecessor - Remove pred as a predecessor of this MachineBasicBlock.
311 /// Don't do this unless you know what you're doing, because it doesn't
312 /// update pred's successors list. Use pred->addSuccessor instead.
314 void addPredecessor(MachineBasicBlock *pred);
316 /// removePredecessor - Remove pred as a predecessor of this
317 /// MachineBasicBlock. Don't do this unless you know what you're
318 /// doing, because it doesn't update pred's successors list. Use
319 /// pred->removeSuccessor instead.
321 void removePredecessor(MachineBasicBlock *pred);
324 std::ostream& operator<<(std::ostream &OS, const MachineBasicBlock &MBB);
326 //===--------------------------------------------------------------------===//
327 // GraphTraits specializations for machine basic block graphs (machine-CFGs)
328 //===--------------------------------------------------------------------===//
330 // Provide specializations of GraphTraits to be able to treat a
331 // MachineFunction as a graph of MachineBasicBlocks...
334 template <> struct GraphTraits<MachineBasicBlock *> {
335 typedef MachineBasicBlock NodeType;
336 typedef MachineBasicBlock::succ_iterator ChildIteratorType;
338 static NodeType *getEntryNode(MachineBasicBlock *BB) { return BB; }
339 static inline ChildIteratorType child_begin(NodeType *N) {
340 return N->succ_begin();
342 static inline ChildIteratorType child_end(NodeType *N) {
343 return N->succ_end();
347 template <> struct GraphTraits<const MachineBasicBlock *> {
348 typedef const MachineBasicBlock NodeType;
349 typedef MachineBasicBlock::const_succ_iterator ChildIteratorType;
351 static NodeType *getEntryNode(const MachineBasicBlock *BB) { return BB; }
352 static inline ChildIteratorType child_begin(NodeType *N) {
353 return N->succ_begin();
355 static inline ChildIteratorType child_end(NodeType *N) {
356 return N->succ_end();
360 // Provide specializations of GraphTraits to be able to treat a
361 // MachineFunction as a graph of MachineBasicBlocks... and to walk it
362 // in inverse order. Inverse order for a function is considered
363 // to be when traversing the predecessor edges of a MBB
364 // instead of the successor edges.
366 template <> struct GraphTraits<Inverse<MachineBasicBlock*> > {
367 typedef MachineBasicBlock NodeType;
368 typedef MachineBasicBlock::pred_iterator ChildIteratorType;
369 static NodeType *getEntryNode(Inverse<MachineBasicBlock *> G) {
372 static inline ChildIteratorType child_begin(NodeType *N) {
373 return N->pred_begin();
375 static inline ChildIteratorType child_end(NodeType *N) {
376 return N->pred_end();
380 template <> struct GraphTraits<Inverse<const MachineBasicBlock*> > {
381 typedef const MachineBasicBlock NodeType;
382 typedef MachineBasicBlock::const_pred_iterator ChildIteratorType;
383 static NodeType *getEntryNode(Inverse<const MachineBasicBlock*> G) {
386 static inline ChildIteratorType child_begin(NodeType *N) {
387 return N->pred_begin();
389 static inline ChildIteratorType child_end(NodeType *N) {
390 return N->pred_end();
394 } // End llvm namespace