Add the `pass_object_size` attribute to clang.

`pass_object_size` is our way of enabling `__builtin_object_size` to
produce high quality results without requiring inlining to happen
everywhere.

A link to the design doc for this attribute is available at the
Differential review link below.

Differential Revision: http://reviews.llvm.org/D13263

llvm-svn: 254554

1 files changed, 6 insertions, 0 deletions

diff --git a/clang/lib/Sema/SemaLambda.cpp b/clang/lib/Sema/SemaLambda.cpp
index 80d497f4e50..3b81df4ef63 100644
--- a/clang/lib/Sema/SemaLambda.cpp
+++ b/clang/lib/Sema/SemaLambda.cpp
@@ -1141,6 +1141,12 @@ static void addFunctionPointerConversion(Sema &S,
                                          SourceRange IntroducerRange,
                                          CXXRecordDecl *Class,
                                          CXXMethodDecl *CallOperator) {
+  // This conversion is explicitly disabled if the lambda's function has
+  // pass_object_size attributes on any of its parameters.
+  if (std::any_of(CallOperator->param_begin(), CallOperator->param_end(),
+                  std::mem_fn(&ParmVarDecl::hasAttr<PassObjectSizeAttr>)))
+    return;
+
   // Add the conversion to function pointer.
   const FunctionProtoType *CallOpProto = 
       CallOperator->getType()->getAs<FunctionProtoType>();