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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/StmtVisitor.h"
#include "llvm/ADT/PostOrderIterator.h"
#include "llvm/ADT/Statistic.h"
#include "llvm/Support/GraphWriter.h"
using namespace clang;
#define DEBUG_TYPE "CallGraph"
STATISTIC(NumObjCCallEdges, "Number of Objective-C method call edges");
STATISTIC(NumBlockCallEdges, "Number of block call edges");
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;
CallGraphNode *CallerNode;
public:
CGBuilder(CallGraph *g, CallGraphNode *N)
: G(g), CallerNode(N) {}
void VisitStmt(Stmt *S) { VisitChildren(S); }
Decl *getDeclFromCall(CallExpr *CE) {
if (FunctionDecl *CalleeDecl = CE->getDirectCallee())
return CalleeDecl;
// Simple detection of a call through a block.
Expr *CEE = CE->getCallee()->IgnoreParenImpCasts();
if (BlockExpr *Block = dyn_cast<BlockExpr>(CEE)) {
NumBlockCallEdges++;
return Block->getBlockDecl();
}
return 0;
}
void addCalledDecl(Decl *D) {
if (G->includeInGraph(D)) {
CallGraphNode *CalleeNode = G->getOrInsertNode(D);
CallerNode->addCallee(CalleeNode, G);
}
}
void VisitCallExpr(CallExpr *CE) {
if (Decl *D = getDeclFromCall(CE))
addCalledDecl(D);
}
// Adds may-call edges for the ObjC message sends.
void VisitObjCMessageExpr(ObjCMessageExpr *ME) {
if (ObjCInterfaceDecl *IDecl = ME->getReceiverInterface()) {
Selector Sel = ME->getSelector();
// Find the callee definition within the same translation unit.
Decl *D = 0;
if (ME->isInstanceMessage())
D = IDecl->lookupPrivateMethod(Sel);
else
D = IDecl->lookupPrivateClassMethod(Sel);
if (D) {
addCalledDecl(D);
NumObjCCallEdges++;
}
}
}
void VisitChildren(Stmt *S) {
for (Stmt::child_range I = S->children(); I; ++I)
if (*I)
static_cast<CGBuilder*>(this)->Visit(*I);
}
};
} // end anonymous namespace
void CallGraph::addNodesForBlocks(DeclContext *D) {
if (BlockDecl *BD = dyn_cast<BlockDecl>(D))
addNodeForDecl(BD, true);
for (auto *I : D->decls())
if (auto *DC = dyn_cast<DeclContext>(I))
addNodesForBlocks(DC);
}
CallGraph::CallGraph() {
Root = getOrInsertNode(0);
}
CallGraph::~CallGraph() {
llvm::DeleteContainerSeconds(FunctionMap);
}
bool CallGraph::includeInGraph(const Decl *D) {
assert(D);
if (!D->getBody())
return false;
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);
// Allocate a new node, mark it as root, and process it's calls.
CallGraphNode *Node = getOrInsertNode(D);
// Process all the calls by this function as well.
CGBuilder builder(this, 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);
// Make Root node a parent of all functions to make sure all are reachable.
if (F != 0)
Root->addCallee(Node, this);
return Node;
}
void CallGraph::print(raw_ostream &OS) const {
OS << " --- Call graph Dump --- \n";
// We are going to print the graph in reverse post order, partially, to make
// sure the output is deterministic.
llvm::ReversePostOrderTraversal<const clang::CallGraph*> RPOT(this);
for (llvm::ReversePostOrderTraversal<const clang::CallGraph*>::rpo_iterator
I = RPOT.begin(), E = RPOT.end(); I != E; ++I) {
const CallGraphNode *N = *I;
OS << " Function: ";
if (N == Root)
OS << "< root >";
else
N->print(OS);
OS << " calls: ";
for (CallGraphNode::const_iterator CI = N->begin(),
CE = N->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");
}
void CallGraphNode::print(raw_ostream &os) const {
if (const NamedDecl *ND = dyn_cast_or_null<NamedDecl>(FD))
return ND->printName(os);
os << "< >";
}
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 >";
}
if (const NamedDecl *ND = dyn_cast_or_null<NamedDecl>(Node->getDecl()))
return ND->getNameAsString();
else
return "< >";
}
};
}