Author: dcoughlin Date: Fri Nov 11 15:31:38 2016 New Revision: 286633 URL: http://llvm.org/viewvc/llvm-project?rev=286633&view=rev Log: [analyzer] Teach RetainCountChecker about VTCompressionSessionEncodeFrame()
The context argument passed to VideoToolbox's VTCompressionSessionEncodeFrame() function is ultimately passed to a callback supplied when creating the compression session and so may be freed by that callback. To suppress false positives in this case, teach the retain count checker to stop tracking that argument. This isn't suppressed by the usual callback context mechanism because the call to VTCompressionSessionEncodeFrame() doesn't include the callback itself. rdar://problem/27685213 Modified: cfe/trunk/lib/StaticAnalyzer/Checkers/RetainCountChecker.cpp cfe/trunk/test/Analysis/retain-release.m Modified: cfe/trunk/lib/StaticAnalyzer/Checkers/RetainCountChecker.cpp URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/StaticAnalyzer/Checkers/RetainCountChecker.cpp?rev=286633&r1=286632&r2=286633&view=diff ============================================================================== --- cfe/trunk/lib/StaticAnalyzer/Checkers/RetainCountChecker.cpp (original) +++ cfe/trunk/lib/StaticAnalyzer/Checkers/RetainCountChecker.cpp Fri Nov 11 15:31:38 2016 @@ -1126,6 +1126,14 @@ RetainSummaryManager::getFunctionSummary // correctly. ScratchArgs = AF.add(ScratchArgs, 12, StopTracking); S = getPersistentSummary(RetEffect::MakeNoRet(), DoNothing, DoNothing); + } else if (FName == "VTCompressionSessionEncodeFrame") { + // The context argument passed to VTCompressionSessionEncodeFrame() + // is passed to the callback specified when creating the session + // (e.g. with VTCompressionSessionCreate()) which can release it. + // To account for this possibility, conservatively stop tracking + // the context. + ScratchArgs = AF.add(ScratchArgs, 5, StopTracking); + S = getPersistentSummary(RetEffect::MakeNoRet(), DoNothing, DoNothing); } else if (FName == "dispatch_set_context" || FName == "xpc_connection_set_context") { // <rdar://problem/11059275> - The analyzer currently doesn't have Modified: cfe/trunk/test/Analysis/retain-release.m URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/test/Analysis/retain-release.m?rev=286633&r1=286632&r2=286633&view=diff ============================================================================== --- cfe/trunk/test/Analysis/retain-release.m (original) +++ cfe/trunk/test/Analysis/retain-release.m Fri Nov 11 15:31:38 2016 @@ -1267,6 +1267,88 @@ void testCVPrefixRetain(CMSampleBufferRe CVBufferRelease(pixelBufAlias); // no-warning } +typedef signed long SInt32; +typedef SInt32 OSStatus; +typedef FourCharCode CMVideoCodecType; + + +typedef UInt32 VTEncodeInfoFlags; enum { + kVTEncodeInfo_Asynchronous = 1UL << 0, + kVTEncodeInfo_FrameDropped = 1UL << 1, +}; +typedef struct +{ + int ignore; +} CMTime; + + +typedef void (*VTCompressionOutputCallback)( + void * _Nullable outputCallbackRefCon, + void * _Nullable sourceFrameRefCon, + OSStatus status, + VTEncodeInfoFlags infoFlags, + _Nullable CMSampleBufferRef sampleBuffer ); + +typedef struct OpaqueVTCompressionSession* VTCompressionSessionRef; + +extern OSStatus +VTCompressionSessionCreate(_Nullable CFAllocatorRef allocator, + int32_t width, + int32_t height, + CMVideoCodecType codecType, + _Nullable CFDictionaryRef encoderSpecification, + _Nullable CFDictionaryRef sourceImageBufferAttributes, + _Nullable CFAllocatorRef compressedDataAllocator, + _Nullable VTCompressionOutputCallback outputCallback, + void * _Nullable outputCallbackRefCon, + CF_RETURNS_RETAINED _Nullable VTCompressionSessionRef * _Nonnull compressionSessionOut); + +extern OSStatus +VTCompressionSessionEncodeFrame( + _Nonnull VTCompressionSessionRef session, + _Nonnull CVImageBufferRef imageBuffer, + CMTime presentationTimeStamp, + CMTime duration, + _Nullable CFDictionaryRef frameProperties, + void * _Nullable sourceFrameRefCon, + VTEncodeInfoFlags * _Nullable infoFlagsOut); + +OSStatus test_VTCompressionSessionCreateAndEncode_CallbackReleases( + _Nullable CFAllocatorRef allocator, + int32_t width, + int32_t height, + CMVideoCodecType codecType, + _Nullable CFDictionaryRef encoderSpecification, + _Nullable CFDictionaryRef sourceImageBufferAttributes, + _Nullable CFAllocatorRef compressedDataAllocator, + _Nullable VTCompressionOutputCallback outputCallback, + + _Nonnull CVImageBufferRef imageBuffer, + CMTime presentationTimeStamp, + CMTime duration, + _Nullable CFDictionaryRef frameProperties +) { + + // The outputCallback is passed both contexts and so can release either. + NSNumber *contextForCreate = [[NSNumber alloc] initWithInt:5]; // no-warning + NSNumber *contextForEncode = [[NSNumber alloc] initWithInt:6]; // no-warning + + VTCompressionSessionRef session = 0; + OSStatus status = VTCompressionSessionCreate(allocator, + width, height, codecType, encoderSpecification, + sourceImageBufferAttributes, + compressedDataAllocator, outputCallback, contextForCreate, + &session); + + VTEncodeInfoFlags encodeInfoFlags; + + status = VTCompressionSessionEncodeFrame(session, imageBuffer, + presentationTimeStamp, duration, frameProperties, contextForEncode, + &encodeInfoFlags); + + return status; +} + //===----------------------------------------------------------------------===// // <rdar://problem/7358899> False leak associated with // CGBitmapContextCreateWithData _______________________________________________ cfe-commits mailing list cfe-commits@lists.llvm.org http://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits