| //===- CallGraph.cpp - AST-based Call graph -------------------------------===// |
| // |
| // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. |
| // See https://llvm.org/LICENSE.txt for license information. |
| // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception |
| // |
| //===----------------------------------------------------------------------===// |
| // |
| // This file defines the AST-based CallGraph. |
| // |
| //===----------------------------------------------------------------------===// |
| |
| #include "clang/Analysis/CallGraph.h" |
| #include "clang/AST/Decl.h" |
| #include "clang/AST/DeclBase.h" |
| #include "clang/AST/DeclObjC.h" |
| #include "clang/AST/Expr.h" |
| #include "clang/AST/ExprObjC.h" |
| #include "clang/AST/Stmt.h" |
| #include "clang/AST/StmtVisitor.h" |
| #include "clang/Basic/IdentifierTable.h" |
| #include "clang/Basic/LLVM.h" |
| #include "llvm/ADT/PostOrderIterator.h" |
| #include "llvm/ADT/STLExtras.h" |
| #include "llvm/ADT/Statistic.h" |
| #include "llvm/Support/Casting.h" |
| #include "llvm/Support/Compiler.h" |
| #include "llvm/Support/DOTGraphTraits.h" |
| #include "llvm/Support/GraphWriter.h" |
| #include "llvm/Support/raw_ostream.h" |
| #include <cassert> |
| #include <memory> |
| #include <string> |
| |
| 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 nullptr; |
| } |
| |
| void addCalledDecl(Decl *D, Expr *CallExpr) { |
| if (G->includeCalleeInGraph(D)) { |
| CallGraphNode *CalleeNode = G->getOrInsertNode(D); |
| CallerNode->addCallee({CalleeNode, CallExpr}); |
| } |
| } |
| |
| void VisitCallExpr(CallExpr *CE) { |
| if (Decl *D = getDeclFromCall(CE)) |
| addCalledDecl(D, CE); |
| VisitChildren(CE); |
| } |
| |
| void VisitLambdaExpr(LambdaExpr *LE) { |
| if (FunctionTemplateDecl *FTD = LE->getDependentCallOperator()) |
| for (FunctionDecl *FD : FTD->specializations()) |
| G->VisitFunctionDecl(FD); |
| else if (CXXMethodDecl *MD = LE->getCallOperator()) |
| G->VisitFunctionDecl(MD); |
| } |
| |
| void VisitCXXNewExpr(CXXNewExpr *E) { |
| if (FunctionDecl *FD = E->getOperatorNew()) |
| addCalledDecl(FD, E); |
| VisitChildren(E); |
| } |
| |
| void VisitCXXConstructExpr(CXXConstructExpr *E) { |
| CXXConstructorDecl *Ctor = E->getConstructor(); |
| if (FunctionDecl *Def = Ctor->getDefinition()) |
| addCalledDecl(Def, E); |
| VisitChildren(E); |
| } |
| |
| // Include the evaluation of the default argument. |
| void VisitCXXDefaultArgExpr(CXXDefaultArgExpr *E) { |
| Visit(E->getExpr()); |
| } |
| |
| // Include the evaluation of the default initializers in a class. |
| void VisitCXXDefaultInitExpr(CXXDefaultInitExpr *E) { |
| Visit(E->getExpr()); |
| } |
| |
| // 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 = nullptr; |
| if (ME->isInstanceMessage()) |
| D = IDecl->lookupPrivateMethod(Sel); |
| else |
| D = IDecl->lookupPrivateClassMethod(Sel); |
| if (D) { |
| addCalledDecl(D, ME); |
| NumObjCCallEdges++; |
| } |
| } |
| } |
| |
| void VisitChildren(Stmt *S) { |
| for (Stmt *SubStmt : S->children()) |
| if (SubStmt) |
| this->Visit(SubStmt); |
| } |
| }; |
| |
| } // 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(nullptr); |
| } |
| |
| CallGraph::~CallGraph() = default; |
| |
| bool CallGraph::includeInGraph(const Decl *D) { |
| assert(D); |
| if (!D->hasBody()) |
| return false; |
| |
| return includeCalleeInGraph(D); |
| } |
| |
| bool CallGraph::includeCalleeInGraph(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->isDependentContext()) |
| return false; |
| |
| IdentifierInfo *II = FD->getIdentifier(); |
| if (II && II->getName().startswith("__inline")) |
| return false; |
| } |
| |
| return true; |
| } |
| |
| void CallGraph::addNodeForDecl(Decl* D, bool IsGlobal) { |
| assert(D); |
| |
| // Allocate a new node, mark it as root, and process its 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); |
| |
| // Include C++ constructor member initializers. |
| if (auto constructor = dyn_cast<CXXConstructorDecl>(D)) { |
| for (CXXCtorInitializer *init : constructor->inits()) { |
| builder.Visit(init->getInit()); |
| } |
| } |
| } |
| |
| CallGraphNode *CallGraph::getNode(const Decl *F) const { |
| FunctionMapTy::const_iterator I = FunctionMap.find(F); |
| if (I == FunctionMap.end()) return nullptr; |
| return I->second.get(); |
| } |
| |
| CallGraphNode *CallGraph::getOrInsertNode(Decl *F) { |
| if (F && !isa<ObjCMethodDecl>(F)) |
| F = F->getCanonicalDecl(); |
| |
| std::unique_ptr<CallGraphNode> &Node = FunctionMap[F]; |
| if (Node) |
| return Node.get(); |
| |
| Node = std::make_unique<CallGraphNode>(F); |
| // Make Root node a parent of all functions to make sure all are reachable. |
| if (F) |
| Root->addCallee({Node.get(), /*Call=*/nullptr}); |
| return Node.get(); |
| } |
| |
| 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 CallGraph *> RPOT(this); |
| for (llvm::ReversePostOrderTraversal<const 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->Callee != Root && "No one can call the root node."); |
| CI->Callee->print(OS); |
| OS << " "; |
| } |
| OS << '\n'; |
| } |
| OS.flush(); |
| } |
| |
| LLVM_DUMP_METHOD 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->printQualifiedName(os); |
| os << "< >"; |
| } |
| |
| LLVM_DUMP_METHOD 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 "< >"; |
| } |
| }; |
| |
| } // namespace llvm |