summaryrefslogtreecommitdiff
path: root/clang/lib/Analysis/CallGraph.cpp
blob: 96a16c3afe05b37b34c8277a4dd1ead41e00335d (about) (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
//== CallGraph.cpp - AST-based Call graph  ----------------------*- C++ -*--==//
//
//                     The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
//  This file defines the AST-based CallGraph.
//
//===----------------------------------------------------------------------===//
#include "clang/Analysis/CallGraph.h"

#include "clang/AST/ASTContext.h"
#include "clang/AST/Decl.h"
#include "clang/AST/StmtVisitor.h"

#include "llvm/Support/GraphWriter.h"

using namespace clang;

namespace {
/// A helper class, which walks the AST and locates all the call sites in the
/// given function body.
class CGBuilder : public StmtVisitor<CGBuilder> {
  CallGraph *G;
  const Decl *FD;
  CallGraphNode *CallerNode;

public:
  CGBuilder(CallGraph *g, const Decl *D, CallGraphNode *N)
    : G(g), FD(D), CallerNode(N) {}

  void VisitStmt(Stmt *S) { VisitChildren(S); }

  void VisitCallExpr(CallExpr *CE) {
    // TODO: We need to handle ObjC method calls as well.
    if (FunctionDecl *CalleeDecl = CE->getDirectCallee())
      if (G->includeInGraph(CalleeDecl)) {
        CallGraphNode *CalleeNode = G->getOrInsertNode(CalleeDecl);
        CallerNode->addCallee(CalleeNode, G);
      }
  }

  void VisitChildren(Stmt *S) {
    for (Stmt::child_range I = S->children(); I; ++I)
      if (*I)
        static_cast<CGBuilder*>(this)->Visit(*I);
  }
};

} // end anonymous namespace

CallGraph::CallGraph() {
  Root = getOrInsertNode(0);
}

CallGraph::~CallGraph() {
  if (!FunctionMap.empty()) {
    for (FunctionMapTy::iterator I = FunctionMap.begin(), E = FunctionMap.end();
        I != E; ++I)
      delete I->second;
    FunctionMap.clear();
  }
}

bool CallGraph::includeInGraph(const Decl *D) {
  if (const FunctionDecl *FD = dyn_cast<FunctionDecl>(D)) {
    // We skip function template definitions, as their semantics is
    // only determined when they are instantiated.
    if (!FD->isThisDeclarationADefinition() ||
        FD->isDependentContext())
      return false;

    IdentifierInfo *II = FD->getIdentifier();
    if (II && II->getName().startswith("__inline"))
      return false;
  }

  if (const ObjCMethodDecl *ID = dyn_cast<ObjCMethodDecl>(D)) {
    if (!ID->isThisDeclarationADefinition())
      return false;
  }

  return true;
}

void CallGraph::addNodeForDecl(Decl* D, bool IsGlobal) {
  assert(D);

  // Do nothing if the node already exists.
  if (FunctionMap.find(D) != FunctionMap.end())
    return;

  // Allocate a new node, mark it as root, and process it's calls.
  CallGraphNode *Node = getOrInsertNode(D);
  if (IsGlobal)
    Root->addCallee(Node, this);

  // Process all the calls by this function as well.
  CGBuilder builder(this, D, Node);
  if (Stmt *Body = D->getBody())
    builder.Visit(Body);
}

CallGraphNode *CallGraph::getNode(const Decl *F) const {
  FunctionMapTy::const_iterator I = FunctionMap.find(F);
  if (I == FunctionMap.end()) return 0;
  return I->second;
}

CallGraphNode *CallGraph::getOrInsertNode(Decl *F) {
  CallGraphNode *&Node = FunctionMap[F];
  if (Node)
    return Node;

  Node = new CallGraphNode(F);
  // If not root, add to the parentless list.
  if (F != 0)
    ParentlessNodes.insert(Node);
  return Node;
}

void CallGraph::print(raw_ostream &OS) const {
  OS << " --- Call graph Dump --- \n";
  for (const_iterator I = begin(), E = end(); I != E; ++I) {
    OS << "  Function: ";
    if (I->second == Root)
      OS << "< root >";
    else
      I->second->print(OS);
    OS << " calls: ";
    for (CallGraphNode::iterator CI = I->second->begin(),
        CE = I->second->end(); CI != CE; ++CI) {
      assert(*CI != Root && "No one can call the root node.");
      (*CI)->print(OS);
      OS << " ";
    }
    OS << '\n';
  }
  OS.flush();
}

void CallGraph::dump() const {
  print(llvm::errs());
}

void CallGraph::viewGraph() const {
  llvm::ViewGraph(this, "CallGraph");
}

StringRef CallGraphNode::getName() const {
  if (const FunctionDecl *D = dyn_cast_or_null<FunctionDecl>(FD))
    if (const IdentifierInfo *II = D->getIdentifier())
      return II->getName();
    return "< >";
}

void CallGraphNode::print(raw_ostream &os) const {
  os << getName();
}

void CallGraphNode::dump() const {
  print(llvm::errs());
}

namespace llvm {

template <>
struct DOTGraphTraits<const CallGraph*> : public DefaultDOTGraphTraits {

  DOTGraphTraits (bool isSimple=false) : DefaultDOTGraphTraits(isSimple) {}

  static std::string getNodeLabel(const CallGraphNode *Node,
                                  const CallGraph *CG) {
    if (CG->getRoot() == Node) {
      return "< root >";
    }
    return Node->getName();
  }

};
}