Also devirtualize calls to a member functions where the containing class has been marked final.

llvm-svn: 117445

clang/lib/CodeGen/CGExprCXX.cpp

@@ -59,10 +59,15 @@ static bool canDevirtualizeMemberFunctionCalls(const Expr *Base,
                                                const CXXMethodDecl *MD) {
   
   // If the member function has the "final" attribute, we know that it can't be
-  // overridden and can therefor devirtualize it.
+  // overridden and can therefore devirtualize it.
   if (MD->hasAttr<FinalAttr>())
     return true;
-  
+
+  // Similarly, if the class itself has the "final" attribute it can't be
+  // overridden and we can therefore devirtualize the member function call.
+  if (MD->getParent()->hasAttr<FinalAttr>())
+    return true;
+
   if (const DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(Base)) {
     if (const VarDecl *VD = dyn_cast<VarDecl>(DRE->getDecl())) {
       // This is a record decl. We know the type and can devirtualize it.

clang/test/CodeGenCXX/attr-final-devirtualize-virtual-function-calls.cpp

@@ -6,7 +6,19 @@ namespace Test1 {
   };
 
   // CHECK: define i32 @_ZN5Test11fEPNS_1AE
-  int f(A* a) {
+  int f(A *a) {
+    // CHECK: ret i32 1
+    return a->f();
+  }
+}
+
+namespace Test2 {
+  struct __attribute__((final)) A {
+    virtual int f() { return 1; }
+  };
+
+  // CHECK: define i32 @_ZN5Test21fEPNS_1AE
+  int f(A *a) {
     // CHECK: ret i32 1
     return a->f();
   }