[ms-cxxabi] Elide dtor access checks for pass-by-val objects in callees

The ABI requires the destructor to be invoked in the callee, but the
standard does not require access checks here so we avoid doing direct
access checks on the destructor.

If we end up needing to define an implicit destructor, we don't skip
access checks for the base class, etc. Those checks are effectively part
of generating the destructor definition, and aren't affected by which TU
the check is performed in.

Differential Revision: http://llvm-reviews.chandlerc.com/D2409

llvm-svn: 199120

1 files changed, 12 insertions, 3 deletions

diff --git a/clang/lib/Sema/SemaChecking.cpp b/clang/lib/Sema/SemaChecking.cpp
index 82b3da6c2e1..0e2b1f64d60 100644
--- a/clang/lib/Sema/SemaChecking.cpp
+++ b/clang/lib/Sema/SemaChecking.cpp
@@ -6241,12 +6241,21 @@ bool Sema::CheckParmsForFunctionDef(ParmVarDecl *const *P,
 
     // MSVC destroys objects passed by value in the callee.  Therefore a
     // function definition which takes such a parameter must be able to call the
-    // object's destructor.
+    // object's destructor.  However, we don't perform any direct access check
+    // on the dtor.
     if (getLangOpts().CPlusPlus && Context.getTargetInfo()
                                        .getCXXABI()
                                        .areArgsDestroyedLeftToRightInCallee()) {
-      if (const RecordType *RT = Param->getType()->getAs<RecordType>())
-        FinalizeVarWithDestructor(Param, RT);
+      if (const RecordType *RT = Param->getType()->getAs<RecordType>()) {
+        CXXRecordDecl *ClassDecl = cast<CXXRecordDecl>(RT->getDecl());
+        if (!ClassDecl->isInvalidDecl() &&
+            !ClassDecl->hasIrrelevantDestructor() &&
+            !ClassDecl->isDependentContext()) {
+          CXXDestructorDecl *Destructor = LookupDestructor(ClassDecl);
+          MarkFunctionReferenced(Param->getLocation(), Destructor);
+          DiagnoseUseOfDecl(Destructor, Param->getLocation());
+        }
+      }
     }
   }