During codegen of a virtual call we would extract any casts in the expression

to see if we had an underlying final class or method, but we would then
use the cast type to do the call, resulting in a direct call to the wrong
method.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@159212 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 16 insertions, 0 deletions

diff --git a/lib/Sema/SemaExpr.cpp b/lib/Sema/SemaExpr.cpp
index 07f3c1d6c7..4dd6f0b552 100644
--- a/lib/Sema/SemaExpr.cpp
+++ b/lib/Sema/SemaExpr.cpp
@@ -10844,6 +10844,22 @@ static void MarkExprReferenced(Sema &SemaRef, SourceLocation Loc,
   }
 
   SemaRef.MarkAnyDeclReferenced(Loc, D);
+
+  // If this is a call to a method via a cast, also mark the method in the
+  // derived class used in case codegen can devirtualize the call.
+  const MemberExpr *ME = dyn_cast<MemberExpr>(E);
+  if (!ME)
+    return;
+  CXXMethodDecl *MD = dyn_cast<CXXMethodDecl>(ME->getMemberDecl());
+  if (!MD)
+    return;
+  const Expr *Base = ME->getBase();
+  const CXXRecordDecl *MostDerivedClassDecl
+    = Base->getMostDerivedClassDeclForType();
+  if (!MostDerivedClassDecl)
+    return;
+  CXXMethodDecl *DM = MD->getCorrespondingMethodInClass(MostDerivedClassDecl);
+  SemaRef.MarkAnyDeclReferenced(Loc, DM);
 } 
 
 /// \brief Perform reference-marking and odr-use handling for a DeclRefExpr.