MachineBasicBlock.h revision 30b8e51addc23fb317c03d093a25828d3d5be45a 
1//===-- llvm/CodeGen/MachineBasicBlock.h ------------------------*- C++ -*-===//
2//
3//                     The LLVM Compiler Infrastructure
4//
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.
7//
8//===----------------------------------------------------------------------===//
9//
10// Collect the sequence of machine instructions for a basic block.
11//
12//===----------------------------------------------------------------------===//
13
14#ifndef LLVM_CODEGEN_MACHINEBASICBLOCK_H
15#define LLVM_CODEGEN_MACHINEBASICBLOCK_H
16
17#include "llvm/CodeGen/MachineInstr.h"
18#include "llvm/ADT/GraphTraits.h"
19#include "llvm/ADT/ilist"
20#include "llvm/Support/Streams.h"
21
22namespace llvm {
23  class MachineFunction;
24
25// ilist_traits
26template <>
27struct ilist_traits<MachineInstr> {
28protected:
29  // this is only set by the MachineBasicBlock owning the ilist
30  friend class MachineBasicBlock;
31  MachineBasicBlock* parent;
32
33public:
34  ilist_traits<MachineInstr>() : parent(0) { }
35
36  static MachineInstr* getPrev(MachineInstr* N) { return N->prev; }
37  static MachineInstr* getNext(MachineInstr* N) { return N->next; }
38
39  static const MachineInstr*
40  getPrev(const MachineInstr* N) { return N->prev; }
41
42  static const MachineInstr*
43  getNext(const MachineInstr* N) { return N->next; }
44
45  static void setPrev(MachineInstr* N, MachineInstr* prev) { N->prev = prev; }
46  static void setNext(MachineInstr* N, MachineInstr* next) { N->next = next; }
47
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);
56};
57
58class BasicBlock;
59
60class MachineBasicBlock {
61public:
62  typedef ilist<MachineInstr> Instructions;
63  Instructions Insts;
64  MachineBasicBlock *Prev, *Next;
65  const BasicBlock *BB;
66  int Number;
67  MachineFunction *Parent;
68
69  /// Predecessors/Successors - Keep track of the predecessor / successor
70  /// basicblocks.
71  std::vector<MachineBasicBlock *> Predecessors;
72  std::vector<MachineBasicBlock *> Successors;
73
74  /// LiveIns - Keep track of the physical registers that are livein of
75  /// the basicblock.
76  std::vector<unsigned> LiveIns;
77
78  /// IsLandingPad - Indicate that this basic block is entered via an
79  /// exception handler.
80  bool IsLandingPad;
81
82public:
83  MachineBasicBlock(const BasicBlock *bb = 0) : Prev(0), Next(0), BB(bb),
84                                                Number(-1), Parent(0),
85                                                IsLandingPad(false) {
86    Insts.parent = this;
87  }
88
89  ~MachineBasicBlock();
90
91  /// getBasicBlock - Return the LLVM basic block that this instance
92  /// corresponded to originally.
93  ///
94  const BasicBlock *getBasicBlock() const { return BB; }
95
96  /// getParent - Return the MachineFunction containing this basic block.
97  ///
98  const MachineFunction *getParent() const { return Parent; }
99  MachineFunction *getParent() { return Parent; }
100
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;
105
106  unsigned size() const { return Insts.size(); }
107  bool empty() const { return Insts.empty(); }
108
109  MachineInstr& front() { return Insts.front(); }
110  MachineInstr& back()  { return Insts.back(); }
111
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();   }
120
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
127  pred_iterator        pred_begin()       { return Predecessors.begin(); }
128  const_pred_iterator  pred_begin() const { return Predecessors.begin(); }
129  pred_iterator        pred_end()         { return Predecessors.end();   }
130  const_pred_iterator  pred_end()   const { return Predecessors.end();   }
131  unsigned             pred_size()  const { return Predecessors.size();  }
132  bool                 pred_empty() const { return Predecessors.empty(); }
133  succ_iterator        succ_begin()       { return Successors.begin();   }
134  const_succ_iterator  succ_begin() const { return Successors.begin();   }
135  succ_iterator        succ_end()         { return Successors.end();     }
136  const_succ_iterator  succ_end()   const { return Successors.end();     }
137  unsigned             succ_size()  const { return Successors.size();    }
138  bool                 succ_empty() const { return Successors.empty();   }
139
140  // LiveIn management methods.
141
142  /// addLiveIn - Add the specified register as a live in.  Note that it
143  /// is an error to add the same register to the same set more than once.
144  void addLiveIn(unsigned Reg)  { LiveIns.push_back(Reg); }
145
146  /// removeLiveIn - Remove the specified register from the live in set.
147  ///
148  void removeLiveIn(unsigned Reg);
149
150  // Iteration support for live in sets.  These sets are kept in sorted
151  // order by their register number.
152  typedef std::vector<unsigned>::iterator       livein_iterator;
153  typedef std::vector<unsigned>::const_iterator const_livein_iterator;
154  livein_iterator       livein_begin()       { return LiveIns.begin(); }
155  const_livein_iterator livein_begin() const { return LiveIns.begin(); }
156  livein_iterator       livein_end()         { return LiveIns.end(); }
157  const_livein_iterator livein_end()   const { return LiveIns.end(); }
158  bool            livein_empty() const { return LiveIns.empty(); }
159
160  /// isLandingPad - Returns true if the block is a landing pad. That is
161  /// this basic block is entered via an exception handler.
162  bool isLandingPad() const { return IsLandingPad; }
163
164  /// setIsLandingPad - Indicates the block is a landing pad.  That is
165  /// this basic block is entered via an exception handler.
166  void setIsLandingPad() { IsLandingPad = true; }
167
168  /// isAccessable - Returns true if the block is alive.  That is, if it has
169  /// predecessors or is an eh landing pad.
170  bool isAccessable() const { return !pred_empty() || isLandingPad(); }
171
172  // Code Layout methods.
173
174  /// moveBefore/moveAfter - move 'this' block before or after the specified
175  /// block.  This only moves the block, it does not modify the CFG or adjust
176  /// potential fall-throughs at the end of the block.
177  void moveBefore(MachineBasicBlock *NewAfter);
178  void moveAfter(MachineBasicBlock *NewBefore);
179
180  // Machine-CFG mutators
181
182  /// addSuccessor - Add succ as a successor of this MachineBasicBlock.
183  /// The Predecessors list of succ is automatically updated.
184  ///
185  void addSuccessor(MachineBasicBlock *succ);
186
187  /// removeSuccessor - Remove successor from the successors list of this
188  /// MachineBasicBlock. The Predecessors list of succ is automatically updated.
189  ///
190  void removeSuccessor(MachineBasicBlock *succ);
191
192  /// removeSuccessor - Remove specified successor from the successors list of
193  /// this MachineBasicBlock. The Predecessors list of succ is automatically
194  /// updated.
195  ///
196  void removeSuccessor(succ_iterator I);
197
198  /// isSuccessor - Return true if the specified MBB is a successor of this
199  /// block.
200  bool isSuccessor(MachineBasicBlock *MBB) const {
201    for (const_succ_iterator I = succ_begin(), E = succ_end(); I != E; ++I)
202      if (*I == MBB)
203        return true;
204    return false;
205  }
206
207  /// getFirstTerminator - returns an iterator to the first terminator
208  /// instruction of this basic block. If a terminator does not exist,
209  /// it returns end()
210  iterator getFirstTerminator();
211
212  void pop_front() { Insts.pop_front(); }
213  void pop_back() { Insts.pop_back(); }
214  void push_back(MachineInstr *MI) { Insts.push_back(MI); }
215  template<typename IT>
216  void insert(iterator I, IT S, IT E) { Insts.insert(I, S, E); }
217  iterator insert(iterator I, MachineInstr *M) { return Insts.insert(I, M); }
218
219  // erase - Remove the specified element or range from the instruction list.
220  // These functions delete any instructions removed.
221  //
222  iterator erase(iterator I)             { return Insts.erase(I); }
223  iterator erase(iterator I, iterator E) { return Insts.erase(I, E); }
224  MachineInstr *remove(MachineInstr *I)  { return Insts.remove(I); }
225  void clear()                           { Insts.clear(); }
226
227  /// splice - Take a block of instructions from MBB 'Other' in the range [From,
228  /// To), and insert them into this MBB right before 'where'.
229  void splice(iterator where, MachineBasicBlock *Other, iterator From,
230              iterator To) {
231    Insts.splice(where, Other->Insts, From, To);
232  }
233
234  // Debugging methods.
235  void dump() const;
236  void print(std::ostream &OS) const;
237  void print(std::ostream *OS) const { if (OS) print(*OS); }
238
239  /// getNumber - MachineBasicBlocks are uniquely numbered at the function
240  /// level, unless they're not in a MachineFunction yet, in which case this
241  /// will return -1.
242  ///
243  int getNumber() const { return Number; }
244  void setNumber(int N) { Number = N; }
245
246private:   // Methods used to maintain doubly linked list of blocks...
247  friend struct ilist_traits<MachineBasicBlock>;
248
249  MachineBasicBlock *getPrev() const { return Prev; }
250  MachineBasicBlock *getNext() const { return Next; }
251  void setPrev(MachineBasicBlock *P) { Prev = P; }
252  void setNext(MachineBasicBlock *N) { Next = N; }
253
254  // Machine-CFG mutators
255
256  /// addPredecessor - Remove pred as a predecessor of this MachineBasicBlock.
257  /// Don't do this unless you know what you're doing, because it doesn't
258  /// update pred's successors list. Use pred->addSuccessor instead.
259  ///
260  void addPredecessor(MachineBasicBlock *pred);
261
262  /// removePredecessor - Remove pred as a predecessor of this
263  /// MachineBasicBlock. Don't do this unless you know what you're
264  /// doing, because it doesn't update pred's successors list. Use
265  /// pred->removeSuccessor instead.
266  ///
267  void removePredecessor(MachineBasicBlock *pred);
268};
269
270std::ostream& operator<<(std::ostream &OS, const MachineBasicBlock &MBB);
271
272//===--------------------------------------------------------------------===//
273// GraphTraits specializations for machine basic block graphs (machine-CFGs)
274//===--------------------------------------------------------------------===//
275
276// Provide specializations of GraphTraits to be able to treat a
277// MachineFunction as a graph of MachineBasicBlocks...
278//
279
280template <> struct GraphTraits<MachineBasicBlock *> {
281  typedef MachineBasicBlock NodeType;
282  typedef MachineBasicBlock::succ_iterator ChildIteratorType;
283
284  static NodeType *getEntryNode(MachineBasicBlock *BB) { return BB; }
285  static inline ChildIteratorType child_begin(NodeType *N) {
286    return N->succ_begin();
287  }
288  static inline ChildIteratorType child_end(NodeType *N) {
289    return N->succ_end();
290  }
291};
292
293template <> struct GraphTraits<const MachineBasicBlock *> {
294  typedef const MachineBasicBlock NodeType;
295  typedef MachineBasicBlock::const_succ_iterator ChildIteratorType;
296
297  static NodeType *getEntryNode(const MachineBasicBlock *BB) { return BB; }
298  static inline ChildIteratorType child_begin(NodeType *N) {
299    return N->succ_begin();
300  }
301  static inline ChildIteratorType child_end(NodeType *N) {
302    return N->succ_end();
303  }
304};
305
306// Provide specializations of GraphTraits to be able to treat a
307// MachineFunction as a graph of MachineBasicBlocks... and to walk it
308// in inverse order.  Inverse order for a function is considered
309// to be when traversing the predecessor edges of a MBB
310// instead of the successor edges.
311//
312template <> struct GraphTraits<Inverse<MachineBasicBlock*> > {
313  typedef MachineBasicBlock NodeType;
314  typedef MachineBasicBlock::pred_iterator ChildIteratorType;
315  static NodeType *getEntryNode(Inverse<MachineBasicBlock *> G) {
316    return G.Graph;
317  }
318  static inline ChildIteratorType child_begin(NodeType *N) {
319    return N->pred_begin();
320  }
321  static inline ChildIteratorType child_end(NodeType *N) {
322    return N->pred_end();
323  }
324};
325
326template <> struct GraphTraits<Inverse<const MachineBasicBlock*> > {
327  typedef const MachineBasicBlock NodeType;
328  typedef MachineBasicBlock::const_pred_iterator ChildIteratorType;
329  static NodeType *getEntryNode(Inverse<const MachineBasicBlock*> G) {
330    return G.Graph;
331  }
332  static inline ChildIteratorType child_begin(NodeType *N) {
333    return N->pred_begin();
334  }
335  static inline ChildIteratorType child_end(NodeType *N) {
336    return N->pred_end();
337  }
338};
339
340} // End llvm namespace
341
342#endif
343