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//== 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/RecursiveASTVisitor.h"
#include "clang/AST/StmtVisitor.h"
#include "llvm/Support/GraphWriter.h"
using namespace clang;
/// Determine if a declaration should be included in the graph.
static bool 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;
}
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 (includeInGraph(CalleeDecl)) {
CallGraphNode *CalleeNode = G->getOrInsertFunction(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);
}
};
/// A helper class which walks the AST declarations.
// TODO: We might want to specialize the visitor to shrink the call graph.
// For example, we might not want to include the inline methods from header
// files.
class CGDeclVisitor : public RecursiveASTVisitor<CGDeclVisitor> {
CallGraph *CG;
public:
CGDeclVisitor(CallGraph * InCG) : CG(InCG) {}
bool VisitFunctionDecl(FunctionDecl *FD) {
// We skip function template definitions, as their semantics is
// only determined when they are instantiated.
if (includeInGraph(FD))
// If this function has external linkage, anything could call it.
// Note, we are not precise here. For example, the function could have
// its address taken.
CG->addToCallGraph(FD, FD->isGlobal());
return true;
}
bool VisitObjCMethodDecl(ObjCMethodDecl *MD) {
if (includeInGraph(MD))
CG->addToCallGraph(MD, true);
return true;
}
};
} // end anonymous namespace
CallGraph::CallGraph() {
Root = getOrInsertFunction(0);
}
CallGraph::~CallGraph() {
if (!FunctionMap.empty()) {
for (FunctionMapTy::iterator I = FunctionMap.begin(), E = FunctionMap.end();
I != E; ++I)
delete I->second;
FunctionMap.clear();
}
}
void CallGraph::addToCallGraph(Decl* D, bool IsGlobal) {
assert(D);
CallGraphNode *Node = getOrInsertFunction(D);
if (IsGlobal)
Root->addCallee(Node, this);
// Process all the calls by this function as well.
CGBuilder builder(this, D, Node);
builder.Visit(D->getBody());
}
void CallGraph::addToCallGraph(TranslationUnitDecl *TU) {
CGDeclVisitor(this).TraverseDecl(TU);
}
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::getOrInsertFunction(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();
}
};
}