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Consumed.h
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1 //===- Consumed.h -----------------------------------------------*- C++ -*-===//
2 //
3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4 // See https://llvm.org/LICENSE.txt for license information.
5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6 //
7 //===----------------------------------------------------------------------===//
8 //
9 // A intra-procedural analysis for checking consumed properties. This is based,
10 // in part, on research on linear types.
11 //
12 //===----------------------------------------------------------------------===//
13 
14 #ifndef LLVM_CLANG_ANALYSIS_ANALYSES_CONSUMED_H
15 #define LLVM_CLANG_ANALYSIS_ANALYSES_CONSUMED_H
16 
18 #include "clang/Analysis/CFG.h"
19 #include "clang/Basic/LLVM.h"
22 #include "llvm/ADT/DenseMap.h"
23 #include "llvm/ADT/SmallVector.h"
24 #include "llvm/ADT/StringRef.h"
25 #include <list>
26 #include <memory>
27 #include <utility>
28 #include <vector>
29 
30 namespace clang {
31 
32 class AnalysisDeclContext;
33 class CXXBindTemporaryExpr;
34 class FunctionDecl;
35 class PostOrderCFGView;
36 class Stmt;
37 class VarDecl;
38 
39 namespace consumed {
40 
41  class ConsumedStmtVisitor;
42 
44  // No state information for the given variable.
46 
50  };
51 
53  using DelayedDiag = std::pair<PartialDiagnosticAt, OptionalNotes>;
54  using DiagList = std::list<DelayedDiag>;
55 
57  public:
59 
60  /// Emit the warnings and notes left by the analysis.
61  virtual void emitDiagnostics() {}
62 
63  /// Warn that a variable's state doesn't match at the entry and exit
64  /// of a loop.
65  ///
66  /// \param Loc -- The location of the end of the loop.
67  ///
68  /// \param VariableName -- The name of the variable that has a mismatched
69  /// state.
71  StringRef VariableName) {}
72 
73  /// Warn about parameter typestate mismatches upon return.
74  ///
75  /// \param Loc -- The SourceLocation of the return statement.
76  ///
77  /// \param ExpectedState -- The state the return value was expected to be
78  /// in.
79  ///
80  /// \param ObservedState -- The state the return value was observed to be
81  /// in.
83  StringRef VariableName,
84  StringRef ExpectedState,
85  StringRef ObservedState) {}
86 
87  // FIXME: Add documentation.
89  StringRef ExpectedState,
90  StringRef ObservedState) {}
91 
92  // FIXME: This can be removed when the attr propagation fix for templated
93  // classes lands.
94  /// Warn about return typestates set for unconsumable types.
95  ///
96  /// \param Loc -- The location of the attributes.
97  ///
98  /// \param TypeName -- The name of the unconsumable type.
100  StringRef TypeName) {}
101 
102  /// Warn about return typestate mismatches.
103  ///
104  /// \param Loc -- The SourceLocation of the return statement.
105  ///
106  /// \param ExpectedState -- The state the return value was expected to be
107  /// in.
108  ///
109  /// \param ObservedState -- The state the return value was observed to be
110  /// in.
112  StringRef ExpectedState,
113  StringRef ObservedState) {}
114 
115  /// Warn about use-while-consumed errors.
116  /// \param MethodName -- The name of the method that was incorrectly
117  /// invoked.
118  ///
119  /// \param State -- The state the object was used in.
120  ///
121  /// \param Loc -- The SourceLocation of the method invocation.
122  virtual void warnUseOfTempInInvalidState(StringRef MethodName,
123  StringRef State,
124  SourceLocation Loc) {}
125 
126  /// Warn about use-while-consumed errors.
127  /// \param MethodName -- The name of the method that was incorrectly
128  /// invoked.
129  ///
130  /// \param State -- The state the object was used in.
131  ///
132  /// \param VariableName -- The name of the variable that holds the unique
133  /// value.
134  ///
135  /// \param Loc -- The SourceLocation of the method invocation.
136  virtual void warnUseInInvalidState(StringRef MethodName,
137  StringRef VariableName,
138  StringRef State,
139  SourceLocation Loc) {}
140  };
141 
143  using VarMapType = llvm::DenseMap<const VarDecl *, ConsumedState>;
144  using TmpMapType =
145  llvm::DenseMap<const CXXBindTemporaryExpr *, ConsumedState>;
146 
147  protected:
148  bool Reachable = true;
149  const Stmt *From = nullptr;
150  VarMapType VarMap;
151  TmpMapType TmpMap;
152 
153  public:
154  ConsumedStateMap() = default;
156  : Reachable(Other.Reachable), From(Other.From), VarMap(Other.VarMap),
157  TmpMap() {}
158 
159  /// Warn if any of the parameters being tracked are not in the state
160  /// they were declared to be in upon return from a function.
161  void checkParamsForReturnTypestate(SourceLocation BlameLoc,
162  ConsumedWarningsHandlerBase &WarningsHandler) const;
163 
164  /// Clear the TmpMap.
165  void clearTemporaries();
166 
167  /// Get the consumed state of a given variable.
168  ConsumedState getState(const VarDecl *Var) const;
169 
170  /// Get the consumed state of a given temporary value.
171  ConsumedState getState(const CXXBindTemporaryExpr *Tmp) const;
172 
173  /// Merge this state map with another map.
174  void intersect(const ConsumedStateMap &Other);
175 
176  void intersectAtLoopHead(const CFGBlock *LoopHead, const CFGBlock *LoopBack,
177  const ConsumedStateMap *LoopBackStates,
178  ConsumedWarningsHandlerBase &WarningsHandler);
179 
180  /// Return true if this block is reachable.
181  bool isReachable() const { return Reachable; }
182 
183  /// Mark the block as unreachable.
184  void markUnreachable();
185 
186  /// Set the source for a decision about the branching of states.
187  /// \param Source -- The statement that was the origin of a branching
188  /// decision.
189  void setSource(const Stmt *Source) { this->From = Source; }
190 
191  /// Set the consumed state of a given variable.
192  void setState(const VarDecl *Var, ConsumedState State);
193 
194  /// Set the consumed state of a given temporary value.
195  void setState(const CXXBindTemporaryExpr *Tmp, ConsumedState State);
196 
197  /// Remove the temporary value from our state map.
198  void remove(const CXXBindTemporaryExpr *Tmp);
199 
200  /// Tests to see if there is a mismatch in the states stored in two
201  /// maps.
202  ///
203  /// \param Other -- The second map to compare against.
204  bool operator!=(const ConsumedStateMap *Other) const;
205  };
206 
208  std::vector<std::unique_ptr<ConsumedStateMap>> StateMapsArray;
209  std::vector<unsigned int> VisitOrder;
210 
211  public:
212  ConsumedBlockInfo() = default;
213 
214  ConsumedBlockInfo(unsigned int NumBlocks, PostOrderCFGView *SortedGraph)
215  : StateMapsArray(NumBlocks), VisitOrder(NumBlocks, 0) {
216  unsigned int VisitOrderCounter = 0;
217  for (const auto BI : *SortedGraph)
218  VisitOrder[BI->getBlockID()] = VisitOrderCounter++;
219  }
220 
221  bool allBackEdgesVisited(const CFGBlock *CurrBlock,
222  const CFGBlock *TargetBlock);
223 
224  void addInfo(const CFGBlock *Block, ConsumedStateMap *StateMap,
225  std::unique_ptr<ConsumedStateMap> &OwnedStateMap);
226  void addInfo(const CFGBlock *Block,
227  std::unique_ptr<ConsumedStateMap> StateMap);
228 
229  ConsumedStateMap* borrowInfo(const CFGBlock *Block);
230 
231  void discardInfo(const CFGBlock *Block);
232 
233  std::unique_ptr<ConsumedStateMap> getInfo(const CFGBlock *Block);
234 
235  bool isBackEdge(const CFGBlock *From, const CFGBlock *To);
236  bool isBackEdgeTarget(const CFGBlock *Block);
237  };
238 
239  /// A class that handles the analysis of uniqueness violations.
241  ConsumedBlockInfo BlockInfo;
242  std::unique_ptr<ConsumedStateMap> CurrStates;
243 
244  ConsumedState ExpectedReturnState;
245 
246  void determineExpectedReturnState(AnalysisDeclContext &AC,
247  const FunctionDecl *D);
248  bool splitState(const CFGBlock *CurrBlock,
249  const ConsumedStmtVisitor &Visitor);
250 
251  public:
253 
255  : WarningsHandler(WarningsHandler) {}
256 
257  ConsumedState getExpectedReturnState() const { return ExpectedReturnState; }
258 
259  /// Check a function's CFG for consumed violations.
260  ///
261  /// We traverse the blocks in the CFG, keeping track of the state of each
262  /// value who's type has uniquness annotations. If methods are invoked in
263  /// the wrong state a warning is issued. Each block in the CFG is traversed
264  /// exactly once.
265  void run(AnalysisDeclContext &AC);
266  };
267 
268 } // namespace consumed
269 
270 } // namespace clang
271 
272 #endif // LLVM_CLANG_ANALYSIS_ANALYSES_CONSUMED_H
Represents a function declaration or definition.
Definition: Decl.h:1748
virtual void warnReturnTypestateForUnconsumableType(SourceLocation Loc, StringRef TypeName)
Warn about return typestates set for unconsumable types.
Definition: Consumed.h:99
Stmt - This represents one statement.
Definition: Stmt.h:66
virtual void warnParamReturnTypestateMismatch(SourceLocation Loc, StringRef VariableName, StringRef ExpectedState, StringRef ObservedState)
Warn about parameter typestate mismatches upon return.
Definition: Consumed.h:82
virtual void warnUseInInvalidState(StringRef MethodName, StringRef VariableName, StringRef State, SourceLocation Loc)
Warn about use-while-consumed errors.
Definition: Consumed.h:136
Represents a variable declaration or definition.
Definition: Decl.h:812
ConsumedState getExpectedReturnState() const
Definition: Consumed.h:257
LineState State
AnalysisDeclContext contains the context data for the function or method under analysis.
Forward-declares and imports various common LLVM datatypes that clang wants to use unqualified...
std::list< DelayedDiag > DiagList
Definition: Consumed.h:54
Represents binding an expression to a temporary.
Definition: ExprCXX.h:1277
Represents a single basic block in a source-level CFG.
Definition: CFG.h:570
virtual void warnLoopStateMismatch(SourceLocation Loc, StringRef VariableName)
Warn that a variable&#39;s state doesn&#39;t match at the entry and exit of a loop.
Definition: Consumed.h:70
bool isReachable() const
Return true if this block is reachable.
Definition: Consumed.h:181
std::pair< PartialDiagnosticAt, OptionalNotes > DelayedDiag
Definition: Consumed.h:53
virtual void emitDiagnostics()
Emit the warnings and notes left by the analysis.
Definition: Consumed.h:61
Encodes a location in the source.
virtual void warnParamTypestateMismatch(SourceLocation LOC, StringRef ExpectedState, StringRef ObservedState)
Definition: Consumed.h:88
virtual void warnReturnTypestateMismatch(SourceLocation Loc, StringRef ExpectedState, StringRef ObservedState)
Warn about return typestate mismatches.
Definition: Consumed.h:111
ConsumedAnalyzer(ConsumedWarningsHandlerBase &WarningsHandler)
Definition: Consumed.h:254
Dataflow Directional Tag Classes.
A class that handles the analysis of uniqueness violations.
Definition: Consumed.h:240
ConsumedBlockInfo(unsigned int NumBlocks, PostOrderCFGView *SortedGraph)
Definition: Consumed.h:214
ConsumedWarningsHandlerBase & WarningsHandler
Definition: Consumed.h:252
static const TypeInfo & getInfo(unsigned id)
Definition: Types.cpp:33
ConsumedStateMap(const ConsumedStateMap &Other)
Definition: Consumed.h:155
Implements a partial diagnostic that can be emitted anwyhere in a DiagnosticBuilder stream...
void setSource(const Stmt *Source)
Set the source for a decision about the branching of states.
Definition: Consumed.h:189
Defines the clang::SourceLocation class and associated facilities.
bool operator!=(CanQual< T > x, CanQual< U > y)
virtual void warnUseOfTempInInvalidState(StringRef MethodName, StringRef State, SourceLocation Loc)
Warn about use-while-consumed errors.
Definition: Consumed.h:122