clang  8.0.0
CallGraph.h
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1 //===- CallGraph.h - AST-based Call graph -----------------------*- C++ -*-===//
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 declares the AST-based CallGraph.
11 //
12 // A call graph for functions whose definitions/bodies are available in the
13 // current translation unit. The graph has a "virtual" root node that contains
14 // edges to all externally available functions.
15 //
16 //===----------------------------------------------------------------------===//
17 
18 #ifndef LLVM_CLANG_ANALYSIS_CALLGRAPH_H
19 #define LLVM_CLANG_ANALYSIS_CALLGRAPH_H
20 
21 #include "clang/AST/Decl.h"
23 #include "llvm/ADT/DenseMap.h"
24 #include "llvm/ADT/GraphTraits.h"
25 #include "llvm/ADT/STLExtras.h"
26 #include "llvm/ADT/SetVector.h"
27 #include "llvm/ADT/SmallVector.h"
28 #include <memory>
29 
30 namespace clang {
31 
32 class CallGraphNode;
33 class Decl;
34 class DeclContext;
35 class Stmt;
36 
37 /// The AST-based call graph.
38 ///
39 /// The call graph extends itself with the given declarations by implementing
40 /// the recursive AST visitor, which constructs the graph by visiting the given
41 /// declarations.
42 class CallGraph : public RecursiveASTVisitor<CallGraph> {
43  friend class CallGraphNode;
44 
45  using FunctionMapTy =
46  llvm::DenseMap<const Decl *, std::unique_ptr<CallGraphNode>>;
47 
48  /// FunctionMap owns all CallGraphNodes.
49  FunctionMapTy FunctionMap;
50 
51  /// This is a virtual root node that has edges to all the functions.
52  CallGraphNode *Root;
53 
54 public:
55  CallGraph();
56  ~CallGraph();
57 
58  /// Populate the call graph with the functions in the given
59  /// declaration.
60  ///
61  /// Recursively walks the declaration to find all the dependent Decls as well.
62  void addToCallGraph(Decl *D) {
63  TraverseDecl(D);
64  }
65 
66  /// Determine if a declaration should be included in the graph.
67  static bool includeInGraph(const Decl *D);
68 
69  /// Lookup the node for the given declaration.
70  CallGraphNode *getNode(const Decl *) const;
71 
72  /// Lookup the node for the given declaration. If none found, insert
73  /// one into the graph.
75 
76  using iterator = FunctionMapTy::iterator;
77  using const_iterator = FunctionMapTy::const_iterator;
78 
79  /// Iterators through all the elements in the graph. Note, this gives
80  /// non-deterministic order.
81  iterator begin() { return FunctionMap.begin(); }
82  iterator end() { return FunctionMap.end(); }
83  const_iterator begin() const { return FunctionMap.begin(); }
84  const_iterator end() const { return FunctionMap.end(); }
85 
86  /// Get the number of nodes in the graph.
87  unsigned size() const { return FunctionMap.size(); }
88 
89  /// \ brief Get the virtual root of the graph, all the functions available
90  /// externally are represented as callees of the node.
91  CallGraphNode *getRoot() const { return Root; }
92 
93  /// Iterators through all the nodes of the graph that have no parent. These
94  /// are the unreachable nodes, which are either unused or are due to us
95  /// failing to add a call edge due to the analysis imprecision.
96  using nodes_iterator = llvm::SetVector<CallGraphNode *>::iterator;
97  using const_nodes_iterator = llvm::SetVector<CallGraphNode *>::const_iterator;
98 
99  void print(raw_ostream &os) const;
100  void dump() const;
101  void viewGraph() const;
102 
104 
105  /// Part of recursive declaration visitation. We recursively visit all the
106  /// declarations to collect the root functions.
108  // We skip function template definitions, as their semantics is
109  // only determined when they are instantiated.
110  if (includeInGraph(FD) && FD->isThisDeclarationADefinition()) {
111  // Add all blocks declared inside this function to the graph.
112  addNodesForBlocks(FD);
113  // If this function has external linkage, anything could call it.
114  // Note, we are not precise here. For example, the function could have
115  // its address taken.
116  addNodeForDecl(FD, FD->isGlobal());
117  }
118  return true;
119  }
120 
121  /// Part of recursive declaration visitation.
123  if (includeInGraph(MD)) {
124  addNodesForBlocks(MD);
125  addNodeForDecl(MD, true);
126  }
127  return true;
128  }
129 
130  // We are only collecting the declarations, so do not step into the bodies.
131  bool TraverseStmt(Stmt *S) { return true; }
132 
133  bool shouldWalkTypesOfTypeLocs() const { return false; }
134  bool shouldVisitTemplateInstantiations() const { return true; }
135 
136 private:
137  /// Add the given declaration to the call graph.
138  void addNodeForDecl(Decl *D, bool IsGlobal);
139 
140  /// Allocate a new node in the graph.
141  CallGraphNode *allocateNewNode(Decl *);
142 };
143 
145 public:
147 
148 private:
149  /// The function/method declaration.
150  Decl *FD;
151 
152  /// The list of functions called from this node.
153  SmallVector<CallRecord, 5> CalledFunctions;
154 
155 public:
156  CallGraphNode(Decl *D) : FD(D) {}
157 
160 
161  /// Iterators through all the callees/children of the node.
162  iterator begin() { return CalledFunctions.begin(); }
163  iterator end() { return CalledFunctions.end(); }
164  const_iterator begin() const { return CalledFunctions.begin(); }
165  const_iterator end() const { return CalledFunctions.end(); }
166 
167  bool empty() const { return CalledFunctions.empty(); }
168  unsigned size() const { return CalledFunctions.size(); }
169 
171  CalledFunctions.push_back(N);
172  }
173 
174  Decl *getDecl() const { return FD; }
175 
176  void print(raw_ostream &os) const;
177  void dump() const;
178 };
179 
180 } // namespace clang
181 
182 // Graph traits for iteration, viewing.
183 namespace llvm {
184 
185 template <> struct GraphTraits<clang::CallGraphNode*> {
189 
190  static NodeType *getEntryNode(clang::CallGraphNode *CGN) { return CGN; }
191  static ChildIteratorType child_begin(NodeType *N) { return N->begin(); }
192  static ChildIteratorType child_end(NodeType *N) { return N->end(); }
193 };
194 
195 template <> struct GraphTraits<const clang::CallGraphNode*> {
197  using NodeRef = const clang::CallGraphNode *;
199 
200  static NodeType *getEntryNode(const clang::CallGraphNode *CGN) { return CGN; }
201  static ChildIteratorType child_begin(NodeType *N) { return N->begin();}
202  static ChildIteratorType child_end(NodeType *N) { return N->end(); }
203 };
204 
205 template <> struct GraphTraits<clang::CallGraph*>
206  : public GraphTraits<clang::CallGraphNode*> {
207  static NodeType *getEntryNode(clang::CallGraph *CGN) {
208  return CGN->getRoot(); // Start at the external node!
209  }
210 
211  static clang::CallGraphNode *
212  CGGetValue(clang::CallGraph::const_iterator::value_type &P) {
213  return P.second.get();
214  }
215 
216  // nodes_iterator/begin/end - Allow iteration over all nodes in the graph
217  using nodes_iterator =
218  mapped_iterator<clang::CallGraph::iterator, decltype(&CGGetValue)>;
219 
221  return nodes_iterator(CG->begin(), &CGGetValue);
222  }
223 
225  return nodes_iterator(CG->end(), &CGGetValue);
226  }
227 
228  static unsigned size(clang::CallGraph *CG) { return CG->size(); }
229 };
230 
231 template <> struct GraphTraits<const clang::CallGraph*> :
232  public GraphTraits<const clang::CallGraphNode*> {
233  static NodeType *getEntryNode(const clang::CallGraph *CGN) {
234  return CGN->getRoot();
235  }
236 
237  static clang::CallGraphNode *
238  CGGetValue(clang::CallGraph::const_iterator::value_type &P) {
239  return P.second.get();
240  }
241 
242  // nodes_iterator/begin/end - Allow iteration over all nodes in the graph
243  using nodes_iterator =
244  mapped_iterator<clang::CallGraph::const_iterator, decltype(&CGGetValue)>;
245 
247  return nodes_iterator(CG->begin(), &CGGetValue);
248  }
249 
251  return nodes_iterator(CG->end(), &CGGetValue);
252  }
253 
254  static unsigned size(const clang::CallGraph *CG) { return CG->size(); }
255 };
256 
257 } // namespace llvm
258 
259 #endif // LLVM_CLANG_ANALYSIS_CALLGRAPH_H
The AST-based call graph.
Definition: CallGraph.h:42
Represents a function declaration or definition.
Definition: Decl.h:1738
void dump() const
Definition: CallGraph.cpp:205
llvm::SetVector< CallGraphNode * >::iterator nodes_iterator
Iterators through all the nodes of the graph that have no parent.
Definition: CallGraph.h:96
DominatorTree GraphTraits specialization so the DominatorTree can be iterable by generic graph iterat...
Definition: Dominators.h:30
Stmt - This represents one statement.
Definition: Stmt.h:66
Decl - This represents one declaration (or definition), e.g.
Definition: DeclBase.h:87
StringRef P
The l-value was an access to a declared entity or something equivalently strong, like the address of ...
const_iterator begin() const
Definition: CallGraph.h:83
SmallVectorImpl< CallRecord >::const_iterator const_iterator
Definition: CallGraph.h:159
llvm::SetVector< CallGraphNode * >::const_iterator const_nodes_iterator
Definition: CallGraph.h:97
ObjCMethodDecl - Represents an instance or class method declaration.
Definition: DeclObjC.h:139
CallGraphNode * getOrInsertNode(Decl *)
Lookup the node for the given declaration.
Definition: CallGraph.cpp:162
static ChildIteratorType child_end(NodeType *N)
Definition: CallGraph.h:202
void addCallee(CallGraphNode *N)
Definition: CallGraph.h:170
bool TraverseDecl(Decl *D)
Recursively visit a declaration, by dispatching to Traverse*Decl() based on the argument&#39;s dynamic ty...
mapped_iterator< clang::CallGraph::const_iterator, decltype(&CGGetValue)> nodes_iterator
Definition: CallGraph.h:244
static unsigned size(const clang::CallGraph *CG)
Definition: CallGraph.h:254
FunctionMapTy::iterator iterator
Definition: CallGraph.h:76
static NodeType * getEntryNode(const clang::CallGraph *CGN)
Definition: CallGraph.h:233
bool shouldWalkTypesOfTypeLocs() const
Definition: CallGraph.h:133
static nodes_iterator nodes_begin(clang::CallGraph *CG)
Definition: CallGraph.h:220
const_iterator begin() const
Definition: CallGraph.h:164
void addNodesForBlocks(DeclContext *D)
Definition: CallGraph.cpp:110
static NodeType * getEntryNode(const clang::CallGraphNode *CGN)
Definition: CallGraph.h:200
static nodes_iterator nodes_begin(const clang::CallGraph *CG)
Definition: CallGraph.h:246
A class that does preorder or postorder depth-first traversal on the entire Clang AST and visits each...
Decl * getDecl() const
Definition: CallGraph.h:174
CallGraphNode(Decl *D)
Definition: CallGraph.h:156
FunctionMapTy::const_iterator const_iterator
Definition: CallGraph.h:77
friend class CallGraphNode
Definition: CallGraph.h:43
bool isThisDeclarationADefinition() const
Returns whether this specific declaration of the function is also a definition that does not contain ...
Definition: Decl.h:1983
SmallVectorImpl< CallRecord >::iterator iterator
Definition: CallGraph.h:158
static clang::CallGraphNode * CGGetValue(clang::CallGraph::const_iterator::value_type &P)
Definition: CallGraph.h:238
static ChildIteratorType child_end(NodeType *N)
Definition: CallGraph.h:192
void print(raw_ostream &os) const
Definition: CallGraph.cpp:177
static ChildIteratorType child_begin(NodeType *N)
Definition: CallGraph.h:201
bool VisitFunctionDecl(FunctionDecl *FD)
Part of recursive declaration visitation.
Definition: CallGraph.h:107
unsigned size() const
Definition: CallGraph.h:168
mapped_iterator< clang::CallGraph::iterator, decltype(&CGGetValue)> nodes_iterator
Definition: CallGraph.h:218
static nodes_iterator nodes_end(clang::CallGraph *CG)
Definition: CallGraph.h:224
bool TraverseStmt(Stmt *S)
Definition: CallGraph.h:131
static ChildIteratorType child_begin(NodeType *N)
Definition: CallGraph.h:191
static bool includeInGraph(const Decl *D)
Determine if a declaration should be included in the graph.
Definition: CallGraph.cpp:125
const_iterator end() const
Definition: CallGraph.h:84
static nodes_iterator nodes_end(const clang::CallGraph *CG)
Definition: CallGraph.h:250
void viewGraph() const
Definition: CallGraph.cpp:209
Dataflow Directional Tag Classes.
DeclContext - This is used only as base class of specific decl types that can act as declaration cont...
Definition: DeclBase.h:1262
static NodeType * getEntryNode(clang::CallGraphNode *CGN)
Definition: CallGraph.h:190
CallGraphNode * getNode(const Decl *) const
Lookup the node for the given declaration.
Definition: CallGraph.cpp:156
CallGraphNode * getRoot() const
\ brief Get the virtual root of the graph, all the functions available externally are represented as ...
Definition: CallGraph.h:91
static NodeType * getEntryNode(clang::CallGraph *CGN)
Definition: CallGraph.h:207
iterator begin()
Iterators through all the callees/children of the node.
Definition: CallGraph.h:162
static clang::CallGraphNode * CGGetValue(clang::CallGraph::const_iterator::value_type &P)
Definition: CallGraph.h:212
static unsigned size(clang::CallGraph *CG)
Definition: CallGraph.h:228
const_iterator end() const
Definition: CallGraph.h:165
void addToCallGraph(Decl *D)
Populate the call graph with the functions in the given declaration.
Definition: CallGraph.h:62
iterator end()
Definition: CallGraph.h:82
unsigned size() const
Get the number of nodes in the graph.
Definition: CallGraph.h:87
bool empty() const
Definition: CallGraph.h:167
bool VisitObjCMethodDecl(ObjCMethodDecl *MD)
Part of recursive declaration visitation.
Definition: CallGraph.h:122
iterator begin()
Iterators through all the elements in the graph.
Definition: CallGraph.h:81
bool isGlobal() const
Determines whether this is a global function.
Definition: Decl.cpp:2914
bool shouldVisitTemplateInstantiations() const
Definition: CallGraph.h:134