LLVM  6.0.0svn
SparsePropagation.h
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1 //===- SparsePropagation.h - Sparse Conditional Property Propagation ------===//
2 //
3 // The LLVM Compiler Infrastructure
4 //
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
7 //
8 //===----------------------------------------------------------------------===//
9 //
10 // This file implements an abstract sparse conditional propagation algorithm,
11 // modeled after SCCP, but with a customizable lattice function.
12 //
13 //===----------------------------------------------------------------------===//
14 
15 #ifndef LLVM_ANALYSIS_SPARSEPROPAGATION_H
16 #define LLVM_ANALYSIS_SPARSEPROPAGATION_H
17 
18 #include "llvm/IR/Instructions.h"
19 #include "llvm/Support/Debug.h"
20 #include <set>
21 
22 #define DEBUG_TYPE "sparseprop"
23 
24 namespace llvm {
25 
26 /// A template for translating between LLVM Values and LatticeKeys. Clients must
27 /// provide a specialization of LatticeKeyInfo for their LatticeKey type.
28 template <class LatticeKey> struct LatticeKeyInfo {
29  // static inline Value *getValueFromLatticeKey(LatticeKey Key);
30  // static inline LatticeKey getLatticeKeyFromValue(Value *V);
31 };
32 
33 template <class LatticeKey, class LatticeVal,
34  class KeyInfo = LatticeKeyInfo<LatticeKey>>
36 
37 /// AbstractLatticeFunction - This class is implemented by the dataflow instance
38 /// to specify what the lattice values are and how they handle merges etc. This
39 /// gives the client the power to compute lattice values from instructions,
40 /// constants, etc. The current requirement is that lattice values must be
41 /// copyable. At the moment, nothing tries to avoid copying. Additionally,
42 /// lattice keys must be able to be used as keys of a mapping data structure.
43 /// Internally, the generic solver currently uses a DenseMap to map lattice keys
44 /// to lattice values. If the lattice key is a non-standard type, a
45 /// specialization of DenseMapInfo must be provided.
46 template <class LatticeKey, class LatticeVal> class AbstractLatticeFunction {
47 private:
48  LatticeVal UndefVal, OverdefinedVal, UntrackedVal;
49 
50 public:
51  AbstractLatticeFunction(LatticeVal undefVal, LatticeVal overdefinedVal,
52  LatticeVal untrackedVal) {
53  UndefVal = undefVal;
54  OverdefinedVal = overdefinedVal;
55  UntrackedVal = untrackedVal;
56  }
57 
58  virtual ~AbstractLatticeFunction() = default;
59 
60  LatticeVal getUndefVal() const { return UndefVal; }
61  LatticeVal getOverdefinedVal() const { return OverdefinedVal; }
62  LatticeVal getUntrackedVal() const { return UntrackedVal; }
63 
64  /// IsUntrackedValue - If the specified LatticeKey is obviously uninteresting
65  /// to the analysis (i.e., it would always return UntrackedVal), this
66  /// function can return true to avoid pointless work.
67  virtual bool IsUntrackedValue(LatticeKey Key) { return false; }
68 
69  /// ComputeLatticeVal - Compute and return a LatticeVal corresponding to the
70  /// given LatticeKey.
71  virtual LatticeVal ComputeLatticeVal(LatticeKey Key) {
72  return getOverdefinedVal();
73  }
74 
75  /// IsSpecialCasedPHI - Given a PHI node, determine whether this PHI node is
76  /// one that the we want to handle through ComputeInstructionState.
77  virtual bool IsSpecialCasedPHI(PHINode *PN) { return false; }
78 
79  /// MergeValues - Compute and return the merge of the two specified lattice
80  /// values. Merging should only move one direction down the lattice to
81  /// guarantee convergence (toward overdefined).
82  virtual LatticeVal MergeValues(LatticeVal X, LatticeVal Y) {
83  return getOverdefinedVal(); // always safe, never useful.
84  }
85 
86  /// ComputeInstructionState - Compute the LatticeKeys that change as a result
87  /// of executing instruction \p I. Their associated LatticeVals are store in
88  /// \p ChangedValues.
89  virtual void
90  ComputeInstructionState(Instruction &I,
91  DenseMap<LatticeKey, LatticeVal> &ChangedValues,
93 
94  /// PrintLatticeVal - Render the given LatticeVal to the specified stream.
95  virtual void PrintLatticeVal(LatticeVal LV, raw_ostream &OS);
96 
97  /// PrintLatticeKey - Render the given LatticeKey to the specified stream.
98  virtual void PrintLatticeKey(LatticeKey Key, raw_ostream &OS);
99 
100  /// GetValueFromLatticeVal - If the given LatticeVal is representable as an
101  /// LLVM value, return it; otherwise, return nullptr. If a type is given, the
102  /// returned value must have the same type. This function is used by the
103  /// generic solver in attempting to resolve branch and switch conditions.
104  virtual Value *GetValueFromLatticeVal(LatticeVal LV, Type *Ty = nullptr) {
105  return nullptr;
106  }
107 };
108 
109 /// SparseSolver - This class is a general purpose solver for Sparse Conditional
110 /// Propagation with a programmable lattice function.
111 template <class LatticeKey, class LatticeVal, class KeyInfo>
112 class SparseSolver {
113 
114  /// LatticeFunc - This is the object that knows the lattice and how to
115  /// compute transfer functions.
117 
118  /// ValueState - Holds the LatticeVals associated with LatticeKeys.
120 
121  /// BBExecutable - Holds the basic blocks that are executable.
122  SmallPtrSet<BasicBlock *, 16> BBExecutable;
123 
124  /// ValueWorkList - Holds values that should be processed.
125  SmallVector<Value *, 64> ValueWorkList;
126 
127  /// BBWorkList - Holds basic blocks that should be processed.
129 
130  using Edge = std::pair<BasicBlock *, BasicBlock *>;
131 
132  /// KnownFeasibleEdges - Entries in this set are edges which have already had
133  /// PHI nodes retriggered.
134  std::set<Edge> KnownFeasibleEdges;
135 
136 public:
137  explicit SparseSolver(
139  : LatticeFunc(Lattice) {}
140  SparseSolver(const SparseSolver &) = delete;
141  SparseSolver &operator=(const SparseSolver &) = delete;
142 
143  /// Solve - Solve for constants and executable blocks.
144  void Solve();
145 
146  void Print(raw_ostream &OS) const;
147 
148  /// getExistingValueState - Return the LatticeVal object corresponding to the
149  /// given value from the ValueState map. If the value is not in the map,
150  /// UntrackedVal is returned, unlike the getValueState method.
151  LatticeVal getExistingValueState(LatticeKey Key) const {
152  auto I = ValueState.find(Key);
153  return I != ValueState.end() ? I->second : LatticeFunc->getUntrackedVal();
154  }
155 
156  /// getValueState - Return the LatticeVal object corresponding to the given
157  /// value from the ValueState map. If the value is not in the map, its state
158  /// is initialized.
159  LatticeVal getValueState(LatticeKey Key);
160 
161  /// isEdgeFeasible - Return true if the control flow edge from the 'From'
162  /// basic block to the 'To' basic block is currently feasible. If
163  /// AggressiveUndef is true, then this treats values with unknown lattice
164  /// values as undefined. This is generally only useful when solving the
165  /// lattice, not when querying it.
166  bool isEdgeFeasible(BasicBlock *From, BasicBlock *To,
167  bool AggressiveUndef = false);
168 
169  /// isBlockExecutable - Return true if there are any known feasible
170  /// edges into the basic block. This is generally only useful when
171  /// querying the lattice.
172  bool isBlockExecutable(BasicBlock *BB) const {
173  return BBExecutable.count(BB);
174  }
175 
176  /// MarkBlockExecutable - This method can be used by clients to mark all of
177  /// the blocks that are known to be intrinsically live in the processed unit.
178  void MarkBlockExecutable(BasicBlock *BB);
179 
180 private:
181  /// UpdateState - When the state of some LatticeKey is potentially updated to
182  /// the given LatticeVal, this function notices and adds the LLVM value
183  /// corresponding the key to the work list, if needed.
184  void UpdateState(LatticeKey Key, LatticeVal LV);
185 
186  /// markEdgeExecutable - Mark a basic block as executable, adding it to the BB
187  /// work list if it is not already executable.
188  void markEdgeExecutable(BasicBlock *Source, BasicBlock *Dest);
189 
190  /// getFeasibleSuccessors - Return a vector of booleans to indicate which
191  /// successors are reachable from a given terminator instruction.
192  void getFeasibleSuccessors(TerminatorInst &TI, SmallVectorImpl<bool> &Succs,
193  bool AggressiveUndef);
194 
195  void visitInst(Instruction &I);
196  void visitPHINode(PHINode &I);
197  void visitTerminatorInst(TerminatorInst &TI);
198 };
199 
200 //===----------------------------------------------------------------------===//
201 // AbstractLatticeFunction Implementation
202 //===----------------------------------------------------------------------===//
203 
204 template <class LatticeKey, class LatticeVal>
206  LatticeVal V, raw_ostream &OS) {
207  if (V == UndefVal)
208  OS << "undefined";
209  else if (V == OverdefinedVal)
210  OS << "overdefined";
211  else if (V == UntrackedVal)
212  OS << "untracked";
213  else
214  OS << "unknown lattice value";
215 }
216 
217 template <class LatticeKey, class LatticeVal>
219  LatticeKey Key, raw_ostream &OS) {
220  OS << "unknown lattice key";
221 }
222 
223 //===----------------------------------------------------------------------===//
224 // SparseSolver Implementation
225 //===----------------------------------------------------------------------===//
226 
227 template <class LatticeKey, class LatticeVal, class KeyInfo>
228 LatticeVal
230  auto I = ValueState.find(Key);
231  if (I != ValueState.end())
232  return I->second; // Common case, in the map
233 
234  if (LatticeFunc->IsUntrackedValue(Key))
235  return LatticeFunc->getUntrackedVal();
236  LatticeVal LV = LatticeFunc->ComputeLatticeVal(Key);
237 
238  // If this value is untracked, don't add it to the map.
239  if (LV == LatticeFunc->getUntrackedVal())
240  return LV;
241  return ValueState[Key] = LV;
242 }
243 
244 template <class LatticeKey, class LatticeVal, class KeyInfo>
246  LatticeVal LV) {
247  auto I = ValueState.find(Key);
248  if (I != ValueState.end() && I->second == LV)
249  return; // No change.
250 
251  // Update the state of the given LatticeKey and add its corresponding LLVM
252  // value to the work list.
253  ValueState[Key] = LV;
254  if (Value *V = KeyInfo::getValueFromLatticeKey(Key))
255  ValueWorkList.push_back(V);
256 }
257 
258 template <class LatticeKey, class LatticeVal, class KeyInfo>
260  BasicBlock *BB) {
261  if (!BBExecutable.insert(BB).second)
262  return;
263  DEBUG(dbgs() << "Marking Block Executable: " << BB->getName() << "\n");
264  BBWorkList.push_back(BB); // Add the block to the work list!
265 }
266 
267 template <class LatticeKey, class LatticeVal, class KeyInfo>
269  BasicBlock *Source, BasicBlock *Dest) {
270  if (!KnownFeasibleEdges.insert(Edge(Source, Dest)).second)
271  return; // This edge is already known to be executable!
272 
273  DEBUG(dbgs() << "Marking Edge Executable: " << Source->getName() << " -> "
274  << Dest->getName() << "\n");
275 
276  if (BBExecutable.count(Dest)) {
277  // The destination is already executable, but we just made an edge
278  // feasible that wasn't before. Revisit the PHI nodes in the block
279  // because they have potentially new operands.
280  for (BasicBlock::iterator I = Dest->begin(); isa<PHINode>(I); ++I)
281  visitPHINode(*cast<PHINode>(I));
282  } else {
283  MarkBlockExecutable(Dest);
284  }
285 }
286 
287 template <class LatticeKey, class LatticeVal, class KeyInfo>
289  TerminatorInst &TI, SmallVectorImpl<bool> &Succs, bool AggressiveUndef) {
290  Succs.resize(TI.getNumSuccessors());
291  if (TI.getNumSuccessors() == 0)
292  return;
293 
294  if (BranchInst *BI = dyn_cast<BranchInst>(&TI)) {
295  if (BI->isUnconditional()) {
296  Succs[0] = true;
297  return;
298  }
299 
300  LatticeVal BCValue;
301  if (AggressiveUndef)
302  BCValue =
303  getValueState(KeyInfo::getLatticeKeyFromValue(BI->getCondition()));
304  else
305  BCValue = getExistingValueState(
306  KeyInfo::getLatticeKeyFromValue(BI->getCondition()));
307 
308  if (BCValue == LatticeFunc->getOverdefinedVal() ||
309  BCValue == LatticeFunc->getUntrackedVal()) {
310  // Overdefined condition variables can branch either way.
311  Succs[0] = Succs[1] = true;
312  return;
313  }
314 
315  // If undefined, neither is feasible yet.
316  if (BCValue == LatticeFunc->getUndefVal())
317  return;
318 
319  Constant *C =
320  dyn_cast_or_null<Constant>(LatticeFunc->GetValueFromLatticeVal(
321  BCValue, BI->getCondition()->getType()));
322  if (!C || !isa<ConstantInt>(C)) {
323  // Non-constant values can go either way.
324  Succs[0] = Succs[1] = true;
325  return;
326  }
327 
328  // Constant condition variables mean the branch can only go a single way
329  Succs[C->isNullValue()] = true;
330  return;
331  }
332 
333  if (TI.isExceptional()) {
334  Succs.assign(Succs.size(), true);
335  return;
336  }
337 
338  if (isa<IndirectBrInst>(TI)) {
339  Succs.assign(Succs.size(), true);
340  return;
341  }
342 
343  SwitchInst &SI = cast<SwitchInst>(TI);
344  LatticeVal SCValue;
345  if (AggressiveUndef)
346  SCValue = getValueState(KeyInfo::getLatticeKeyFromValue(SI.getCondition()));
347  else
348  SCValue = getExistingValueState(
349  KeyInfo::getLatticeKeyFromValue(SI.getCondition()));
350 
351  if (SCValue == LatticeFunc->getOverdefinedVal() ||
352  SCValue == LatticeFunc->getUntrackedVal()) {
353  // All destinations are executable!
354  Succs.assign(TI.getNumSuccessors(), true);
355  return;
356  }
357 
358  // If undefined, neither is feasible yet.
359  if (SCValue == LatticeFunc->getUndefVal())
360  return;
361 
362  Constant *C = dyn_cast_or_null<Constant>(LatticeFunc->GetValueFromLatticeVal(
363  SCValue, SI.getCondition()->getType()));
364  if (!C || !isa<ConstantInt>(C)) {
365  // All destinations are executable!
366  Succs.assign(TI.getNumSuccessors(), true);
367  return;
368  }
369  SwitchInst::CaseHandle Case = *SI.findCaseValue(cast<ConstantInt>(C));
370  Succs[Case.getSuccessorIndex()] = true;
371 }
372 
373 template <class LatticeKey, class LatticeVal, class KeyInfo>
375  BasicBlock *From, BasicBlock *To, bool AggressiveUndef) {
376  SmallVector<bool, 16> SuccFeasible;
377  TerminatorInst *TI = From->getTerminator();
378  getFeasibleSuccessors(*TI, SuccFeasible, AggressiveUndef);
379 
380  for (unsigned i = 0, e = TI->getNumSuccessors(); i != e; ++i)
381  if (TI->getSuccessor(i) == To && SuccFeasible[i])
382  return true;
383 
384  return false;
385 }
386 
387 template <class LatticeKey, class LatticeVal, class KeyInfo>
389  TerminatorInst &TI) {
390  SmallVector<bool, 16> SuccFeasible;
391  getFeasibleSuccessors(TI, SuccFeasible, true);
392 
393  BasicBlock *BB = TI.getParent();
394 
395  // Mark all feasible successors executable...
396  for (unsigned i = 0, e = SuccFeasible.size(); i != e; ++i)
397  if (SuccFeasible[i])
398  markEdgeExecutable(BB, TI.getSuccessor(i));
399 }
400 
401 template <class LatticeKey, class LatticeVal, class KeyInfo>
403  // The lattice function may store more information on a PHINode than could be
404  // computed from its incoming values. For example, SSI form stores its sigma
405  // functions as PHINodes with a single incoming value.
406  if (LatticeFunc->IsSpecialCasedPHI(&PN)) {
407  DenseMap<LatticeKey, LatticeVal> ChangedValues;
408  LatticeFunc->ComputeInstructionState(PN, ChangedValues, *this);
409  for (auto &ChangedValue : ChangedValues)
410  if (ChangedValue.second != LatticeFunc->getUntrackedVal())
411  UpdateState(ChangedValue.first, ChangedValue.second);
412  return;
413  }
414 
415  LatticeKey Key = KeyInfo::getLatticeKeyFromValue(&PN);
416  LatticeVal PNIV = getValueState(Key);
417  LatticeVal Overdefined = LatticeFunc->getOverdefinedVal();
418 
419  // If this value is already overdefined (common) just return.
420  if (PNIV == Overdefined || PNIV == LatticeFunc->getUntrackedVal())
421  return; // Quick exit
422 
423  // Super-extra-high-degree PHI nodes are unlikely to ever be interesting,
424  // and slow us down a lot. Just mark them overdefined.
425  if (PN.getNumIncomingValues() > 64) {
426  UpdateState(Key, Overdefined);
427  return;
428  }
429 
430  // Look at all of the executable operands of the PHI node. If any of them
431  // are overdefined, the PHI becomes overdefined as well. Otherwise, ask the
432  // transfer function to give us the merge of the incoming values.
433  for (unsigned i = 0, e = PN.getNumIncomingValues(); i != e; ++i) {
434  // If the edge is not yet known to be feasible, it doesn't impact the PHI.
435  if (!isEdgeFeasible(PN.getIncomingBlock(i), PN.getParent(), true))
436  continue;
437 
438  // Merge in this value.
439  LatticeVal OpVal =
440  getValueState(KeyInfo::getLatticeKeyFromValue(PN.getIncomingValue(i)));
441  if (OpVal != PNIV)
442  PNIV = LatticeFunc->MergeValues(PNIV, OpVal);
443 
444  if (PNIV == Overdefined)
445  break; // Rest of input values don't matter.
446  }
447 
448  // Update the PHI with the compute value, which is the merge of the inputs.
449  UpdateState(Key, PNIV);
450 }
451 
452 template <class LatticeKey, class LatticeVal, class KeyInfo>
454  // PHIs are handled by the propagation logic, they are never passed into the
455  // transfer functions.
456  if (PHINode *PN = dyn_cast<PHINode>(&I))
457  return visitPHINode(*PN);
458 
459  // Otherwise, ask the transfer function what the result is. If this is
460  // something that we care about, remember it.
461  DenseMap<LatticeKey, LatticeVal> ChangedValues;
462  LatticeFunc->ComputeInstructionState(I, ChangedValues, *this);
463  for (auto &ChangedValue : ChangedValues)
464  if (ChangedValue.second != LatticeFunc->getUntrackedVal())
465  UpdateState(ChangedValue.first, ChangedValue.second);
466 
467  if (TerminatorInst *TI = dyn_cast<TerminatorInst>(&I))
468  visitTerminatorInst(*TI);
469 }
470 
471 template <class LatticeKey, class LatticeVal, class KeyInfo>
473  // Process the work lists until they are empty!
474  while (!BBWorkList.empty() || !ValueWorkList.empty()) {
475  // Process the value work list.
476  while (!ValueWorkList.empty()) {
477  Value *V = ValueWorkList.back();
478  ValueWorkList.pop_back();
479 
480  DEBUG(dbgs() << "\nPopped off V-WL: " << *V << "\n");
481 
482  // "V" got into the work list because it made a transition. See if any
483  // users are both live and in need of updating.
484  for (User *U : V->users())
485  if (Instruction *Inst = dyn_cast<Instruction>(U))
486  if (BBExecutable.count(Inst->getParent())) // Inst is executable?
487  visitInst(*Inst);
488  }
489 
490  // Process the basic block work list.
491  while (!BBWorkList.empty()) {
492  BasicBlock *BB = BBWorkList.back();
493  BBWorkList.pop_back();
494 
495  DEBUG(dbgs() << "\nPopped off BBWL: " << *BB);
496 
497  // Notify all instructions in this basic block that they are newly
498  // executable.
499  for (Instruction &I : *BB)
500  visitInst(I);
501  }
502  }
503 }
504 
505 template <class LatticeKey, class LatticeVal, class KeyInfo>
507  raw_ostream &OS) const {
508  if (ValueState.empty())
509  return;
510 
511  LatticeKey Key;
512  LatticeVal LV;
513 
514  OS << "ValueState:\n";
515  for (auto &Entry : ValueState) {
516  std::tie(Key, LV) = Entry;
517  if (LV == LatticeFunc->getUntrackedVal())
518  continue;
519  OS << "\t";
520  LatticeFunc->PrintLatticeVal(LV, OS);
521  OS << ": ";
522  LatticeFunc->PrintLatticeKey(Key, OS);
523  OS << "\n";
524  }
525 }
526 } // end namespace llvm
527 
528 #undef DEBUG_TYPE
529 
530 #endif // LLVM_ANALYSIS_SPARSEPROPAGATION_H
uint64_t CallInst * C
void Print(raw_ostream &OS) const
static GCMetadataPrinterRegistry::Add< ErlangGCPrinter > X("erlang", "erlang-compatible garbage collector")
virtual LatticeVal MergeValues(LatticeVal X, LatticeVal Y)
MergeValues - Compute and return the merge of the two specified lattice values.
SparseSolver(AbstractLatticeFunction< LatticeKey, LatticeVal > *Lattice)
Compute iterated dominance frontiers using a linear time algorithm.
Definition: AllocatorList.h:24
virtual void PrintLatticeVal(LatticeVal LV, raw_ostream &OS)
PrintLatticeVal - Render the given LatticeVal to the specified stream.
BasicBlock * getSuccessor(unsigned idx) const
Return the specified successor.
LLVM_ATTRIBUTE_ALWAYS_INLINE size_type size() const
Definition: SmallVector.h:136
Value * getCondition() const
virtual Value * GetValueFromLatticeVal(LatticeVal LV, Type *Ty=nullptr)
GetValueFromLatticeVal - If the given LatticeVal is representable as an LLVM value, return it; otherwise, return nullptr.
iterator begin()
Instruction iterator methods.
Definition: BasicBlock.h:252
static GCMetadataPrinterRegistry::Add< OcamlGCMetadataPrinter > Y("ocaml", "ocaml 3.10-compatible collector")
void assign(size_type NumElts, const T &Elt)
Definition: SmallVector.h:427
Key
PAL metadata keys.
bool isNullValue() const
Return true if this is the value that would be returned by getNullValue.
Definition: Constants.cpp:86
void Solve()
Solve - Solve for constants and executable blocks.
Type * getType() const
All values are typed, get the type of this value.
Definition: Value.h:245
iterator find(const_arg_type_t< KeyT > Val)
Definition: DenseMap.h:146
virtual void PrintLatticeKey(LatticeKey Key, raw_ostream &OS)
PrintLatticeKey - Render the given LatticeKey to the specified stream.
Subclasses of this class are all able to terminate a basic block.
Definition: InstrTypes.h:54
* if(!EatIfPresent(lltok::kw_thread_local)) return false
ParseOptionalThreadLocal := /*empty.
LLVM Basic Block Representation.
Definition: BasicBlock.h:59
The instances of the Type class are immutable: once they are created, they are never changed...
Definition: Type.h:46
Conditional or Unconditional Branch instruction.
This is an important base class in LLVM.
Definition: Constant.h:42
LatticeVal getUntrackedVal() const
const Instruction & back() const
Definition: BasicBlock.h:266
size_type count(ConstPtrType Ptr) const
count - Return 1 if the specified pointer is in the set, 0 otherwise.
Definition: SmallPtrSet.h:382
SparseSolver - This class is a general purpose solver for Sparse Conditional Propagation with a progr...
Value * getIncomingValue(unsigned i) const
Return incoming value number x.
AbstractLatticeFunction - This class is implemented by the dataflow instance to specify what the latt...
LatticeVal getExistingValueState(LatticeKey Key) const
getExistingValueState - Return the LatticeVal object corresponding to the given value from the ValueS...
SmallPtrSet - This class implements a set which is optimized for holding SmallSize or less elements...
Definition: SmallPtrSet.h:418
bool isExceptional() const
Definition: InstrTypes.h:84
This is a &#39;vector&#39; (really, a variable-sized array), optimized for the case when the array is small...
Definition: SmallVector.h:864
bool isEdgeFeasible(BasicBlock *From, BasicBlock *To, bool AggressiveUndef=false)
isEdgeFeasible - Return true if the control flow edge from the &#39;From&#39; basic block to the &#39;To&#39; basic b...
unsigned getNumIncomingValues() const
Return the number of incoming edges.
CaseIt findCaseValue(const ConstantInt *C)
Search all of the case values for the specified constant.
raw_ostream & dbgs()
dbgs() - This returns a reference to a raw_ostream for debugging messages.
Definition: Debug.cpp:132
LatticeVal getValueState(LatticeKey Key)
getValueState - Return the LatticeVal object corresponding to the given value from the ValueState map...
iterator_range< user_iterator > users()
Definition: Value.h:401
InstListType::iterator iterator
Instruction iterators...
Definition: BasicBlock.h:91
unsigned getSuccessorIndex() const
Returns TerminatorInst&#39;s successor index for current case successor.
virtual bool IsSpecialCasedPHI(PHINode *PN)
IsSpecialCasedPHI - Given a PHI node, determine whether this PHI node is one that the we want to hand...
AbstractLatticeFunction(LatticeVal undefVal, LatticeVal overdefinedVal, LatticeVal untrackedVal)
bool isBlockExecutable(BasicBlock *BB) const
isBlockExecutable - Return true if there are any known feasible edges into the basic block...
virtual bool IsUntrackedValue(LatticeKey Key)
IsUntrackedValue - If the specified LatticeKey is obviously uninteresting to the analysis (i...
StringRef getName() const
Return a constant reference to the value&#39;s name.
Definition: Value.cpp:220
BasicBlock * getIncomingBlock(unsigned i) const
Return incoming basic block number i.
LatticeVal getOverdefinedVal() const
#define I(x, y, z)
Definition: MD5.cpp:58
iterator end()
Definition: DenseMap.h:79
Multiway switch.
unsigned getNumSuccessors() const
Return the number of successors that this terminator has.
void MarkBlockExecutable(BasicBlock *BB)
MarkBlockExecutable - This method can be used by clients to mark all of the blocks that are known to ...
LLVM Value Representation.
Definition: Value.h:73
This class implements an extremely fast bulk output stream that can only output to a stream...
Definition: raw_ostream.h:44
#define DEBUG(X)
Definition: Debug.h:118
const TerminatorInst * getTerminator() const LLVM_READONLY
Returns the terminator instruction if the block is well formed or null if the block is not well forme...
Definition: BasicBlock.cpp:120
virtual LatticeVal ComputeLatticeVal(LatticeKey Key)
ComputeLatticeVal - Compute and return a LatticeVal corresponding to the given LatticeKey.
const BasicBlock * getParent() const
Definition: Instruction.h:66
void resize(size_type N)
Definition: SmallVector.h:355
A template for translating between LLVM Values and LatticeKeys.