Author: george.karpenkov Date: Mon Mar 19 18:16:46 2018 New Revision: 327935
URL: http://llvm.org/viewvc/llvm-project?rev=327935&view=rev Log: [analyzer] Improve performance of NoStoreFuncVisitor Compute modifying frames lazily on demand. Differential Revision: https://reviews.llvm.org/D44503 Modified: cfe/trunk/lib/StaticAnalyzer/Core/BugReporterVisitors.cpp Modified: cfe/trunk/lib/StaticAnalyzer/Core/BugReporterVisitors.cpp URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/StaticAnalyzer/Core/BugReporterVisitors.cpp?rev=327935&r1=327934&r2=327935&view=diff ============================================================================== --- cfe/trunk/lib/StaticAnalyzer/Core/BugReporterVisitors.cpp (original) +++ cfe/trunk/lib/StaticAnalyzer/Core/BugReporterVisitors.cpp Mon Mar 19 18:16:46 2018 @@ -226,7 +226,6 @@ class NoStoreFuncVisitor final const SubRegion *RegionOfInterest; static constexpr const char *DiagnosticsMsg = "Returning without writing to '"; - bool Initialized = false; /// Frames writing into \c RegionOfInterest. /// This visitor generates a note only if a function does not write into @@ -234,10 +233,10 @@ class NoStoreFuncVisitor final /// by looking at the node associated with the exit from the function /// (usually the return statement). To avoid recomputing the same information /// many times (going up the path for each node and checking whether the - /// region was written into) we instead pre-compute and store all - /// stack frames along the path which write into the region of interest - /// on the first \c VisitNode invocation. + /// region was written into) we instead lazily compute the + /// stack frames along the path which write into the region of interest. llvm::SmallPtrSet<const StackFrameContext *, 32> FramesModifyingRegion; + llvm::SmallPtrSet<const StackFrameContext *, 32> FramesModifyingCalculated; public: NoStoreFuncVisitor(const SubRegion *R) : RegionOfInterest(R) {} @@ -251,10 +250,6 @@ public: const ExplodedNode *PrevN, BugReporterContext &BRC, BugReport &BR) override { - if (!Initialized) { - findModifyingFrames(N); - Initialized = true; - } const LocationContext *Ctx = N->getLocationContext(); const StackFrameContext *SCtx = Ctx->getCurrentStackFrame(); @@ -262,7 +257,7 @@ public: auto CallExitLoc = N->getLocationAs<CallExitBegin>(); // No diagnostic if region was modified inside the frame. - if (!CallExitLoc || FramesModifyingRegion.count(SCtx)) + if (!CallExitLoc) return nullptr; CallEventRef<> Call = @@ -272,8 +267,9 @@ public: const SourceManager &SM = BRC.getSourceManager(); if (const auto *CCall = dyn_cast<CXXConstructorCall>(Call)) { const MemRegion *ThisRegion = CCall->getCXXThisVal().getAsRegion(); - if (RegionOfInterest->isSubRegionOf(ThisRegion) && - !CCall->getDecl()->isImplicit()) + if (RegionOfInterest->isSubRegionOf(ThisRegion) + && !CCall->getDecl()->isImplicit() + && !isRegionOfInterestModifiedInFrame(N)) return notModifiedInConstructorDiagnostics(Ctx, SM, PP, *CallExitLoc, CCall, ThisRegion); } @@ -285,10 +281,15 @@ public: unsigned IndirectionLevel = 1; QualType T = PVD->getType(); while (const MemRegion *R = S.getAsRegion()) { - if (RegionOfInterest->isSubRegionOf(R) && - !isPointerToConst(PVD->getType())) + if (RegionOfInterest->isSubRegionOf(R) + && !isPointerToConst(PVD->getType())) { + + if (isRegionOfInterestModifiedInFrame(N)) + return nullptr; + return notModifiedDiagnostics( Ctx, SM, PP, *CallExitLoc, Call, PVD, R, IndirectionLevel); + } QualType PT = T->getPointeeType(); if (PT.isNull() || PT->isVoidType()) break; S = State->getSVal(R, PT); @@ -301,18 +302,39 @@ public: } private: + /// Check and lazily calculate whether the region of interest is + /// modified in the stack frame to which \p N belongs. + /// The calculation is cached in FramesModifyingRegion. + bool isRegionOfInterestModifiedInFrame(const ExplodedNode *N) { + const LocationContext *Ctx = N->getLocationContext(); + const StackFrameContext *SCtx = Ctx->getCurrentStackFrame(); + if (!FramesModifyingCalculated.count(SCtx)) + findModifyingFrames(N); + return FramesModifyingRegion.count(SCtx); + } + + /// Write to \c FramesModifyingRegion all stack frames along - /// the path which modify \c RegionOfInterest. + /// the path in the current stack frame which modify \c RegionOfInterest. void findModifyingFrames(const ExplodedNode *N) { - ProgramStateRef LastReturnState; + assert(N->getLocationAs<CallExitBegin>()); + ProgramStateRef LastReturnState = N->getState(); + SVal ValueAtReturn = LastReturnState->getSVal(RegionOfInterest); + const LocationContext *Ctx = N->getLocationContext(); + const StackFrameContext *OriginalSCtx = Ctx->getCurrentStackFrame(); + do { ProgramStateRef State = N->getState(); auto CallExitLoc = N->getLocationAs<CallExitBegin>(); if (CallExitLoc) { LastReturnState = State; + ValueAtReturn = LastReturnState->getSVal(RegionOfInterest); } - if (LastReturnState && - wasRegionOfInterestModifiedAt(N, LastReturnState)) { + + FramesModifyingCalculated.insert( + N->getLocationContext()->getCurrentStackFrame()); + + if (wasRegionOfInterestModifiedAt(N, LastReturnState, ValueAtReturn)) { const StackFrameContext *SCtx = N->getLocationContext()->getCurrentStackFrame(); while (!SCtx->inTopFrame()) { @@ -323,6 +345,11 @@ private: } } + // Stop calculation at the call to the current function. + if (auto CE = N->getLocationAs<CallEnter>()) + if (CE->getCalleeContext() == OriginalSCtx) + break; + N = N->getFirstPred(); } while (N); } @@ -331,8 +358,12 @@ private: /// where \p ReturnState is a state associated with the return /// from the current frame. bool wasRegionOfInterestModifiedAt(const ExplodedNode *N, - ProgramStateRef ReturnState) { - SVal ValueAtReturn = ReturnState->getSVal(RegionOfInterest); + ProgramStateRef ReturnState, + SVal ValueAtReturn) { + if (!N->getLocationAs<PostStore>() + && !N->getLocationAs<PostInitializer>() + && !N->getLocationAs<PostStmt>()) + return false; // Writing into region of interest. if (auto PS = N->getLocationAs<PostStmt>()) _______________________________________________ cfe-commits mailing list cfe-commits@lists.llvm.org http://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
