From de39c3462e8b2b1dff58639e7ce64fa5b02bd7a7 Mon Sep 17 00:00:00 2001
From: Jordan Rupprecht <rupprecht@google.com>
Date: Fri, 12 Jul 2019 00:32:08 +0000
Subject: [PATCH] Re-Revert Devirtualize destructor of final class.

This reverts r365509 (git commit d088720edad9c29ee0d622b5d69092e18a9ac0bd)

This is a second revert[1] due to failures in internal test cases (shared offline) found during more thorough testing.

[1] Original patch commited as r364100, reverted as r364359, recommitted as r365509

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@365850 91177308-0d34-0410-b5e6-96231b3b80d8
---
 lib/CodeGen/CGExprCXX.cpp                   | 30 +++------------------
 test/CodeGenCXX/devirtualize-dtor-final.cpp | 23 ----------------
 2 files changed, 3 insertions(+), 50 deletions(-)
 delete mode 100644 test/CodeGenCXX/devirtualize-dtor-final.cpp

diff --git a/lib/CodeGen/CGExprCXX.cpp b/lib/CodeGen/CGExprCXX.cpp
index fdca769988..25b0abbc03 100644
--- a/lib/CodeGen/CGExprCXX.cpp
+++ b/lib/CodeGen/CGExprCXX.cpp
@@ -1865,33 +1865,9 @@ static void EmitObjectDelete(CodeGenFunction &CGF,
       Dtor = RD->getDestructor();
 
       if (Dtor->isVirtual()) {
-        bool UseVirtualCall = true;
-        const Expr *Base = DE->getArgument();
-        if (auto *DevirtualizedDtor =
-                dyn_cast_or_null<const CXXDestructorDecl>(
-                    Dtor->getDevirtualizedMethod(
-                        Base, CGF.CGM.getLangOpts().AppleKext))) {
-          UseVirtualCall = false;
-          const CXXRecordDecl *DevirtualizedClass =
-              DevirtualizedDtor->getParent();
-          if (declaresSameEntity(getCXXRecord(Base), DevirtualizedClass)) {
-            // Devirtualized to the class of the base type (the type of the
-            // whole expression).
-            Dtor = DevirtualizedDtor;
-          } else {
-            // Devirtualized to some other type. Would need to cast the this
-            // pointer to that type but we don't have support for that yet, so
-            // do a virtual call. FIXME: handle the case where it is
-            // devirtualized to the derived type (the type of the inner
-            // expression) as in EmitCXXMemberOrOperatorMemberCallExpr.
-            UseVirtualCall = true;
-          }
-        }
-        if (UseVirtualCall) {
-          CGF.CGM.getCXXABI().emitVirtualObjectDelete(CGF, DE, Ptr, ElementType,
-                                                      Dtor);
-          return;
-        }
+        CGF.CGM.getCXXABI().emitVirtualObjectDelete(CGF, DE, Ptr, ElementType,
+                                                    Dtor);
+        return;
       }
     }
   }
diff --git a/test/CodeGenCXX/devirtualize-dtor-final.cpp b/test/CodeGenCXX/devirtualize-dtor-final.cpp
deleted file mode 100644
index ea11be773f..0000000000
--- a/test/CodeGenCXX/devirtualize-dtor-final.cpp
+++ /dev/null
@@ -1,23 +0,0 @@
-// RUN: %clang_cc1 -triple i386-unknown-unknown -std=c++11 %s -emit-llvm -o - | FileCheck %s
-
-namespace Test1 {
-  struct A { virtual ~A() {} };
-  struct B final : A {};
-  struct C : A { virtual ~C() final {} };
-  struct D { virtual ~D() final = 0; };
-  // CHECK-LABEL: define void @_ZN5Test13fooEPNS_1BE
-  void foo(B *b) {
-    // CHECK: call void @_ZN5Test11BD1Ev
-    delete b;
-  }
-  // CHECK-LABEL: define void @_ZN5Test14foo2EPNS_1CE
-  void foo2(C *c) {
-    // CHECK: call void @_ZN5Test11CD1Ev
-    delete c;
-  }
-  // CHECK-LABEL: define void @_ZN5Test14evilEPNS_1DE
-  void evil(D *p) {
-    // CHECK-NOT: call void @_ZN5Test11DD1Ev
-    delete p;
-  }
-}
-- 
2.40.0