[analyzer] Teach RetainCountChecker about CVFooRetain

Change the retain count checker to treat CoreFoundation-style "CV"-prefixed
reference types from CoreVideo similarly to CoreGraphics types. With this
change, we treat CVFooRetain() on a CVFooRef type as a retain. CVFooRelease()
APIs are annotated as consuming their parameter, so this change prevents false
positives about incorrect decrements of reference counts.

<rdar://problem/27116090>

llvm-svn: 278382

diff --git a/clang/lib/StaticAnalyzer/Checkers/RetainCountChecker.cpp b/clang/lib/StaticAnalyzer/Checkers/RetainCountChecker.cpp
index b646127..6bb0727 100644 (file)
--- a/clang/lib/StaticAnalyzer/Checkers/RetainCountChecker.cpp
+++ b/clang/lib/StaticAnalyzer/Checkers/RetainCountChecker.cpp
@@ -1171,8 +1171,9 @@ RetainSummaryManager::getFunctionSummary(const FunctionDecl *FD) {
         break;
       }
 
-      // For CoreGraphics ('CG') types.
-      if (cocoa::isRefType(RetTy, "CG", FName)) {
+      // For CoreGraphics ('CG') and CoreVideo ('CV') types.
+      if (cocoa::isRefType(RetTy, "CG", FName) ||
+          cocoa::isRefType(RetTy, "CV", FName)) {
         if (isRetain(FD, FName))
           S = getUnarySummary(FT, cfretain);
         else
@@ -3372,12 +3373,13 @@ bool RetainCountChecker::evalCall(const CallExpr *CE, CheckerContext &C) const {
     // Handle: id NSMakeCollectable(CFTypeRef)
     canEval = II->isStr("NSMakeCollectable");
   } else if (ResultTy->isPointerType()) {
-    // Handle: (CF|CG)Retain
+    // Handle: (CF|CG|CV)Retain
     //         CFAutorelease
     //         CFMakeCollectable
     // It's okay to be a little sloppy here (CGMakeCollectable doesn't exist).
     if (cocoa::isRefType(ResultTy, "CF", FName) ||
-        cocoa::isRefType(ResultTy, "CG", FName)) {
+        cocoa::isRefType(ResultTy, "CG", FName) ||
+        cocoa::isRefType(ResultTy, "CV", FName)) {
       canEval = isRetain(FD, FName) || isAutorelease(FD, FName) ||
                 isMakeCollectable(FD, FName);
     }

diff --git a/clang/test/Analysis/retain-release.m b/clang/test/Analysis/retain-release.m
index f0d91e3..3acf86c 100644 (file)
--- a/clang/test/Analysis/retain-release.m
+++ b/clang/test/Analysis/retain-release.m
@@ -1247,6 +1247,26 @@ CVReturn rdar_7283567_2(CFAllocatorRef allocator, size_t width, size_t height,
               pixelBufferAttributes, pixelBufferOut) ;
 }
 
+#pragma clang arc_cf_code_audited begin
+typedef struct SomeOpaqueStruct *CMSampleBufferRef;
+CVImageBufferRef _Nonnull CMSampleBufferGetImageBuffer(CMSampleBufferRef _Nonnull sbuf);
+#pragma clang arc_cf_code_audited end
+
+CVBufferRef _Nullable CVBufferRetain(CVBufferRef _Nullable buffer);
+void CVBufferRelease(CF_CONSUMED CVBufferRef _Nullable buffer);
+
+void testCVPrefixRetain(CMSampleBufferRef sbuf) {
+  // Make sure RetainCountChecker treats CVFooRetain() as a CF-style retain.
+  CVPixelBufferRef pixelBuf = CMSampleBufferGetImageBuffer(sbuf);
+  CVBufferRetain(pixelBuf);
+  CVBufferRelease(pixelBuf); // no-warning
+
+
+  // Make sure result of CVFooRetain() is the same as its argument.
+  CVPixelBufferRef pixelBufAlias = CVBufferRetain(pixelBuf);
+  CVBufferRelease(pixelBufAlias); // no-warning
+}
+
 //===----------------------------------------------------------------------===//
 // <rdar://problem/7358899> False leak associated with 
 //  CGBitmapContextCreateWithData