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+//=======- VirtualCallChecker.cpp --------------------------------*- 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 a checker that checks virtual function calls during
+// construction or destruction of C++ objects.
+//
+//===----------------------------------------------------------------------===//
+
+#include "ClangSACheckers.h"
+#include "clang/AST/DeclCXX.h"
+#include "clang/AST/StmtVisitor.h"
+#include "llvm/Support/SaveAndRestore.h"
+#include "clang/StaticAnalyzer/Core/PathSensitive/AnalysisManager.h"
+#include "clang/StaticAnalyzer/Core/Checker.h"
+#include "clang/StaticAnalyzer/Core/BugReporter/BugReporter.h"
+#include "llvm/ADT/SmallString.h"
+
+using namespace clang;
+using namespace ento;
+
+namespace {
+
+class WalkAST : public StmtVisitor<WalkAST> {
+ BugReporter &BR;
+ AnalysisDeclContext *AC;
+
+ typedef const CallExpr * WorkListUnit;
+ typedef SmallVector<WorkListUnit, 20> DFSWorkList;
+
+ /// A vector representing the worklist which has a chain of CallExprs.
+ DFSWorkList WList;
+
+ // PreVisited : A CallExpr to this FunctionDecl is in the worklist, but the
+ // body has not been visited yet.
+ // PostVisited : A CallExpr to this FunctionDecl is in the worklist, and the
+ // body has been visited.
+ enum Kind { NotVisited,
+ PreVisited, /**< A CallExpr to this FunctionDecl is in the
+ worklist, but the body has not yet been
+ visited. */
+ PostVisited /**< A CallExpr to this FunctionDecl is in the
+ worklist, and the body has been visited. */
+ } K;
+
+ /// A DenseMap that records visited states of FunctionDecls.
+ llvm::DenseMap<const FunctionDecl *, Kind> VisitedFunctions;
+
+ /// The CallExpr whose body is currently being visited. This is used for
+ /// generating bug reports. This is null while visiting the body of a
+ /// constructor or destructor.
+ const CallExpr *visitingCallExpr;
+
+public:
+ WalkAST(BugReporter &br, AnalysisDeclContext *ac)
+ : BR(br),
+ AC(ac),
+ visitingCallExpr(0) {}
+
+ bool hasWork() const { return !WList.empty(); }
+
+ /// This method adds a CallExpr to the worklist and marks the callee as
+ /// being PreVisited.
+ void Enqueue(WorkListUnit WLUnit) {
+ const FunctionDecl *FD = WLUnit->getDirectCallee();
+ if (!FD || !FD->getBody())
+ return;
+ Kind &K = VisitedFunctions[FD];
+ if (K != NotVisited)
+ return;
+ K = PreVisited;
+ WList.push_back(WLUnit);
+ }
+
+ /// This method returns an item from the worklist without removing it.
+ WorkListUnit Dequeue() {
+ assert(!WList.empty());
+ return WList.back();
+ }
+
+ void Execute() {
+ while (hasWork()) {
+ WorkListUnit WLUnit = Dequeue();
+ const FunctionDecl *FD = WLUnit->getDirectCallee();
+ assert(FD && FD->getBody());
+
+ if (VisitedFunctions[FD] == PreVisited) {
+ // If the callee is PreVisited, walk its body.
+ // Visit the body.
+ SaveAndRestore<const CallExpr *> SaveCall(visitingCallExpr, WLUnit);
+ Visit(FD->getBody());
+
+ // Mark the function as being PostVisited to indicate we have
+ // scanned the body.
+ VisitedFunctions[FD] = PostVisited;
+ continue;
+ }
+
+ // Otherwise, the callee is PostVisited.
+ // Remove it from the worklist.
+ assert(VisitedFunctions[FD] == PostVisited);
+ WList.pop_back();
+ }
+ }
+
+ // Stmt visitor methods.
+ void VisitCallExpr(CallExpr *CE);
+ void VisitCXXMemberCallExpr(CallExpr *CE);
+ void VisitStmt(Stmt *S) { VisitChildren(S); }
+ void VisitChildren(Stmt *S);
+
+ void ReportVirtualCall(const CallExpr *CE, bool isPure);
+
+};
+} // end anonymous namespace
+
+//===----------------------------------------------------------------------===//
+// AST walking.
+//===----------------------------------------------------------------------===//
+
+void WalkAST::VisitChildren(Stmt *S) {
+ for (Stmt::child_iterator I = S->child_begin(), E = S->child_end(); I!=E; ++I)
+ if (Stmt *child = *I)
+ Visit(child);
+}
+
+void WalkAST::VisitCallExpr(CallExpr *CE) {
+ VisitChildren(CE);
+ Enqueue(CE);
+}
+
+void WalkAST::VisitCXXMemberCallExpr(CallExpr *CE) {
+ VisitChildren(CE);
+ bool callIsNonVirtual = false;
+
+ // Several situations to elide for checking.
+ if (MemberExpr *CME = dyn_cast<MemberExpr>(CE->getCallee())) {
+ // If the member access is fully qualified (i.e., X::F), then treat
+ // this as a non-virtual call and do not warn.
+ if (CME->getQualifier())
+ callIsNonVirtual = true;
+
+ // Elide analyzing the call entirely if the base pointer is not 'this'.
+ if (Expr *base = CME->getBase()->IgnoreImpCasts())
+ if (!isa<CXXThisExpr>(base))
+ return;
+ }
+
+ // Get the callee.
+ const CXXMethodDecl *MD = dyn_cast<CXXMethodDecl>(CE->getDirectCallee());
+ if (MD && MD->isVirtual() && !callIsNonVirtual)
+ ReportVirtualCall(CE, MD->isPure());
+
+ Enqueue(CE);
+}
+
+void WalkAST::ReportVirtualCall(const CallExpr *CE, bool isPure) {
+ SmallString<100> buf;
+ llvm::raw_svector_ostream os(buf);
+
+ os << "Call Path : ";
+ // Name of current visiting CallExpr.
+ os << *CE->getDirectCallee();
+
+ // Name of the CallExpr whose body is current walking.
+ if (visitingCallExpr)
+ os << " <-- " << *visitingCallExpr->getDirectCallee();
+ // Names of FunctionDecls in worklist with state PostVisited.
+ for (SmallVectorImpl<const CallExpr *>::iterator I = WList.end(),
+ E = WList.begin(); I != E; --I) {
+ const FunctionDecl *FD = (*(I-1))->getDirectCallee();
+ assert(FD);
+ if (VisitedFunctions[FD] == PostVisited)
+ os << " <-- " << *FD;
+ }
+
+ PathDiagnosticLocation CELoc =
+ PathDiagnosticLocation::createBegin(CE, BR.getSourceManager(), AC);
+ SourceRange R = CE->getCallee()->getSourceRange();
+
+ if (isPure) {
+ os << "\n" << "Call pure virtual functions during construction or "
+ << "destruction may leads undefined behaviour";
+ BR.EmitBasicReport(AC->getDecl(),
+ "Call pure virtual function during construction or "
+ "Destruction",
+ "Cplusplus",
+ os.str(), CELoc, &R, 1);
+ return;
+ }
+ else {
+ os << "\n" << "Call virtual functions during construction or "
+ << "destruction will never go to a more derived class";
+ BR.EmitBasicReport(AC->getDecl(),
+ "Call virtual function during construction or "
+ "Destruction",
+ "Cplusplus",
+ os.str(), CELoc, &R, 1);
+ return;
+ }
+}
+
+//===----------------------------------------------------------------------===//
+// VirtualCallChecker
+//===----------------------------------------------------------------------===//
+
+namespace {
+class VirtualCallChecker : public Checker<check::ASTDecl<CXXRecordDecl> > {
+public:
+ void checkASTDecl(const CXXRecordDecl *RD, AnalysisManager& mgr,
+ BugReporter &BR) const {
+ WalkAST walker(BR, mgr.getAnalysisDeclContext(RD));
+
+ // Check the constructors.
+ for (CXXRecordDecl::ctor_iterator I = RD->ctor_begin(), E = RD->ctor_end();
+ I != E; ++I) {
+ if (!I->isCopyOrMoveConstructor())
+ if (Stmt *Body = I->getBody()) {
+ walker.Visit(Body);
+ walker.Execute();
+ }
+ }
+
+ // Check the destructor.
+ if (CXXDestructorDecl *DD = RD->getDestructor())
+ if (Stmt *Body = DD->getBody()) {
+ walker.Visit(Body);
+ walker.Execute();
+ }
+ }
+};
+}
+
+void ento::registerVirtualCallChecker(CheckerManager &mgr) {
+ mgr.registerChecker<VirtualCallChecker>();
+}