r327935 - [analyzer] Improve performance of NoStoreFuncVisitor
George Karpenkov via cfe-commits
cfe-commits at lists.llvm.org
Mon Mar 19 18:16:46 PDT 2018
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>())
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