Maintain PS4 ABI compatibility

[dyung]

Summary

In r331136, a change was made to the compiler to fix a problem with how clang applied the packed attribute to classes. This is an ABI breaking change for the PS4 target, so this change maintains the broken behavior for the PS4 target.

cfe/trunk/lib/AST/RecordLayoutBuilder.cpp

if (Base->IsVirtual)
       HasExternalLayout = External.getExternalNVBaseOffset(Base->Class, Offset);
     else
       HasExternalLayout = External.getExternalVBaseOffset(Base->Class, Offset);
   }
   
   // Clang <= 6 incorrectly applied the 'packed' attribute to base classes.
   // Per GCC's documentation, it only applies to non-static data members.
   CharUnits UnpackedBaseAlign = Layout.getNonVirtualAlignment();
-  CharUnits BaseAlign = (Packed && Context.getLangOpts().getClangABICompat() <=
-                                       LangOptions::ClangABI::Ver6)
-                            ? CharUnits::One()
-                            : UnpackedBaseAlign;
+  CharUnits BaseAlign =
+      (Packed && ((Context.getLangOpts().getClangABICompat() <=
+                   LangOptions::ClangABI::Ver6) ||
+                  Context.getTargetInfo().getTriple().isPS4()))
 
   // If we have an empty base class, try to place it at offset 0.
   if (Base->Class->isEmpty() &&
       (!HasExternalLayout || Offset == CharUnits::Zero()) &&
       EmptySubobjects->CanPlaceBaseAtOffset(Base, CharUnits::Zero())) {
     setSize(std::max(getSize(), Layout.getSize()));
     UpdateAlignment(BaseAlign, UnpackedBaseAlign);
 

cfe/trunk/test/CodeGenCXX/alignment.cpp

 // RUN: %clang_cc1 %s -emit-llvm -o - -triple=x86_64-apple-darwin10 | FileCheck %s --check-prefix=CHECK --check-prefix=CHECK-NOCOMPAT
 // RUN: %clang_cc1 %s -emit-llvm -o - -triple=x86_64-apple-darwin10 -fclang-abi-compat=6.0 | FileCheck %s --check-prefix=CHECK --check-prefix=CHECK-V6COMPAT
+// RUN: %clang_cc1 %s -emit-llvm -o - -triple=x86_64-scei-ps4 | FileCheck %s --check-prefix=CHECK --check-prefix=CHECK-V6COMPAT
 
 extern int int_source();
 extern void int_sink(int x);
 
 namespace test0 {
   struct A {
     int aField;
     int bField;