When warning about unsafe uses of dispatch_once, specially handle the

crazy case where dispatch_once gets redefined as a macro that calls
_dispatch_once (which calls the real dispatch_once).  Users want to
see the warning in their own code.

Fixes <rdar://problem/11617767>

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@163816 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 13 insertions, 1 deletions

diff --git a/lib/StaticAnalyzer/Checkers/MacOSXAPIChecker.cpp b/lib/StaticAnalyzer/Checkers/MacOSXAPIChecker.cpp
index cfdb55df73..97bb80c9e1 100644
--- a/lib/StaticAnalyzer/Checkers/MacOSXAPIChecker.cpp
+++ b/lib/StaticAnalyzer/Checkers/MacOSXAPIChecker.cpp
@@ -70,6 +70,16 @@ void MacOSXAPIChecker::CheckDispatchOnce(CheckerContext &C, const CallExpr *CE,
     BT_dispatchOnce.reset(new BugType("Improper use of 'dispatch_once'",
                                       "Mac OS X API"));
 
+  // Handle _dispatch_once, which in some versions of the OS X SDK that
+  // dispatch_once is a macro that wraps a call to _dispatch_once, which
+  // then calls the real dispatch_once.  Users do not care; they just
+  // want the warning at the top-level call.
+  if (CE->getLocStart().isMacroID()) {
+    StringRef TrimmedFName = FName.ltrim("_");
+    if (TrimmedFName != FName)
+      FName = TrimmedFName;
+  }
+  
   SmallString<256> S;
   llvm::raw_svector_ostream os(S);
   os << "Call to '" << FName << "' uses";
@@ -99,7 +109,9 @@ void MacOSXAPIChecker::checkPreStmt(const CallExpr *CE,
 
   SubChecker SC =
     llvm::StringSwitch<SubChecker>(Name)
-      .Cases("dispatch_once", "dispatch_once_f",
+      .Cases("dispatch_once",
+             "_dispatch_once",
+             "dispatch_once_f",
              &MacOSXAPIChecker::CheckDispatchOnce)
       .Default(NULL);