[analyzer] Improve misleading RetainCountChcker diagnostic under ARC

Under automated reference counting the analyzer treats a methods -- even those
starting with  'copy' and friends -- as returning an unowned value. This is
because ownership of CoreFoundation objects must be transferred to ARC
with __bridge_transfer or CFBridgingRelease() before being returned as
ARC-managed bridged objects.

Unfortunately this could lead to a poor diagnostic inside copy methods under
ARC where the analyzer would complain about a leak of a returned CF value inside
a method "whose name does not start with 'copy'" -- even though the name did
start with 'copy'.

This commit improves the diagnostic under ARC to say inside a method "returned
from a method managed by Automated Reference Counting".

rdar://problem/28849667

llvm-svn: 286694

1 files changed, 9 insertions, 4 deletions

diff --git a/clang/lib/StaticAnalyzer/Checkers/RetainCountChecker.cpp b/clang/lib/StaticAnalyzer/Checkers/RetainCountChecker.cpp
index 26026dd9a26..7c31cbaf51e 100644
--- a/clang/lib/StaticAnalyzer/Checkers/RetainCountChecker.cpp
+++ b/clang/lib/StaticAnalyzer/Checkers/RetainCountChecker.cpp
@@ -2367,10 +2367,15 @@ CFRefLeakReportVisitor::getEndPath(BugReporterContext &BRC,
       os << "that is annotated as NS_RETURNS_NOT_RETAINED";
     else {
       if (const ObjCMethodDecl *MD = dyn_cast<ObjCMethodDecl>(D)) {
-        os << "whose name ('" << MD->getSelector().getAsString()
-           << "') does not start with 'copy', 'mutableCopy', 'alloc' or 'new'."
-              "  This violates the naming convention rules"
-              " given in the Memory Management Guide for Cocoa";
+        if (BRC.getASTContext().getLangOpts().ObjCAutoRefCount) {
+          os << "managed by Automated Reference Counting";
+        } else {
+          os << "whose name ('" << MD->getSelector().getAsString()
+             << "') does not start with "
+                "'copy', 'mutableCopy', 'alloc' or 'new'."
+                "  This violates the naming convention rules"
+                " given in the Memory Management Guide for Cocoa";
+        }
       }
       else {
         const FunctionDecl *FD = cast<FunctionDecl>(D);