lib/Index/CallGraph.cpp

   1 //== CallGraph.cpp - Call graph building ------------------------*- 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 defined the CallGraph and CGBuilder classes.
  11 //
  12 //===----------------------------------------------------------------------===//
  13
  14 #include "clang/Index/CallGraph.h"
  15
  16 #include "clang/AST/ASTContext.h"
  17 #include "clang/AST/StmtVisitor.h"
  18
  19 #include "llvm/Support/GraphWriter.h"
  20
  21 using namespace clang;
  22 using namespace idx;
  23
  24 namespace {
  25 class CGBuilder : public StmtVisitor<CGBuilder> {
  26
  27   CallGraph &G;
  28   FunctionDecl *FD;
  29
  30   Entity CallerEnt;
  31
  32   CallGraphNode *CallerNode;
  33
  34 public:
  35   CGBuilder(CallGraph &g, FunctionDecl *fd, Entity E, CallGraphNode *N)
  36     : G(g), FD(fd), CallerEnt(E), CallerNode(N) {}
  37
  38   void VisitStmt(Stmt *S) { VisitChildren(S); }
  39
  40   void VisitCallExpr(CallExpr *CE);
  41
  42   void VisitChildren(Stmt *S) {
  43     for (Stmt::child_iterator I=S->child_begin(), E=S->child_end(); I != E;++I)
  44       if (*I)
  45         static_cast<CGBuilder*>(this)->Visit(*I);
  46   }
  47 };
  48 }
  49
  50 void CGBuilder::VisitCallExpr(CallExpr *CE) {
  51   if (FunctionDecl *CalleeDecl = CE->getDirectCallee()) {
  52     Entity Ent = Entity::get(CalleeDecl, G.getProgram());
  53     CallGraphNode *CalleeNode = G.getOrInsertFunction(Ent);
  54     CallerNode->addCallee(ASTLocation(FD, CE), CalleeNode);
  55   }
  56 }
  57
  58 CallGraph::CallGraph(Program &P) : Prog(P), Root(0) {
  59   ExternalCallingNode = getOrInsertFunction(Entity());
  60 }
  61
  62 CallGraph::~CallGraph() {
  63   if (!FunctionMap.empty()) {
  64     for (FunctionMapTy::iterator I = FunctionMap.begin(), E = FunctionMap.end();
  65         I != E; ++I)
  66       delete I->second;
  67     FunctionMap.clear();
  68   }
  69 }
  70
  71 void CallGraph::addTU(ASTContext& Ctx) {
  72   DeclContext *DC = Ctx.getTranslationUnitDecl();
  73   for (DeclContext::decl_iterator I = DC->decls_begin(), E = DC->decls_end();
  74        I != E; ++I) {
  75
  76     if (FunctionDecl *FD = dyn_cast<FunctionDecl>(*I)) {
  77       if (FD->isThisDeclarationADefinition()) {
  78         // Set caller's ASTContext.
  79         Entity Ent = Entity::get(FD, Prog);
  80         CallGraphNode *Node = getOrInsertFunction(Ent);
  81         CallerCtx[Node] = &Ctx;
  82
  83         // If this function has external linkage, anything could call it.
  84         if (FD->isGlobal())
  85           ExternalCallingNode->addCallee(idx::ASTLocation(), Node);
  86
  87         // Set root node to 'main' function.
  88         if (FD->getNameAsString() == "main")
  89           Root = Node;
  90
  91         CGBuilder builder(*this, FD, Ent, Node);
  92         builder.Visit(FD->getBody());
  93       }
  94     }
  95   }
  96 }
  97
  98 CallGraphNode *CallGraph::getOrInsertFunction(Entity F) {
  99   CallGraphNode *&Node = FunctionMap[F];
 100   if (Node)
 101     return Node;
 102
 103   return Node = new CallGraphNode(F);
 104 }
 105
 106 Decl *CallGraph::getDecl(CallGraphNode *Node) {
 107   // Get the function's context.
 108   ASTContext *Ctx = CallerCtx[Node];
 109
 110   return Node->getDecl(*Ctx);
 111 }
 112
 113 void CallGraph::print(llvm::raw_ostream &os) {
 114   for (iterator I = begin(), E = end(); I != E; ++I) {
 115     if (I->second->hasCallee()) {
 116       os << "function: " << I->first.getPrintableName()
 117          << " calls:\n";
 118       for (CallGraphNode::iterator CI = I->second->begin(),
 119              CE = I->second->end(); CI != CE; ++CI) {
 120         os << "    " << CI->second->getName();
 121       }
 122       os << '\n';
 123     }
 124   }
 125 }
 126
 127 void CallGraph::dump() {
 128   print(llvm::errs());
 129 }
 130
 131 void CallGraph::ViewCallGraph() const {
 132   llvm::ViewGraph(*this, "CallGraph");
 133 }
 134
 135 namespace llvm {
 136
 137 template <>
 138 struct DOTGraphTraits<CallGraph> : public DefaultDOTGraphTraits {
 139
 140   DOTGraphTraits (bool isSimple=false) : DefaultDOTGraphTraits(isSimple) {}
 141
 142   static std::string getNodeLabel(const CallGraphNode *Node,
 143                                   const CallGraph &CG) {
 144     return Node->getName();
 145
 146   }
 147
 148 };
 149
 150 }