Revert r247218: "Fix Clang-tidy misc-use-override warnings, other minor fixes"

Seems it broke the Polly build.
From http://lab.llvm.org:8011/builders/perf-x86_64-penryn-O3-polly-fast/builds/11687/steps/compile/logs/stdio:

In file included from /home/grosser/buildslave/perf-x86_64-penryn-O3-polly-fast/llvm.src/lib/TableGen/Record.cpp:14:0:
/home/grosser/buildslave/perf-x86_64-penryn-O3-polly-fast/llvm.src/include/llvm/TableGen/Record.h:369:3: error: looser throw specifier for 'virtual llvm::TypedInit::~TypedInit()'
/home/grosser/buildslave/perf-x86_64-penryn-O3-polly-fast/llvm.src/include/llvm/TableGen/Record.h:270:11: error:   overriding 'virtual llvm::Init::~Init() noexcept (true)'

llvm-svn: 247222

clang/lib/CodeGen/ObjectFilePCHContainerOperations.cpp

@@ -30,7 +30,6 @@
 #include "llvm/Object/ObjectFile.h"
 #include "llvm/Support/TargetRegistry.h"
 #include <memory>
-
 using namespace clang;
 
 #define DEBUG_TYPE "pchcontainer"
@@ -140,7 +139,7 @@ public:
     CodeGenOpts.SplitDwarfFile = OutputFileName;
   }
 
-  ~PCHContainerGenerator() override = default;
+  virtual ~PCHContainerGenerator() {}
 
   void Initialize(ASTContext &Context) override {
     assert(!Ctx && "initialized multiple times");
@@ -255,7 +254,7 @@ public:
   }
 };
 
-} // anonymous namespace
+} // namespace
 
 std::unique_ptr<ASTConsumer>
 ObjectFilePCHContainerWriter::CreatePCHContainerGenerator(
@@ -291,4 +290,5 @@ void ObjectFilePCHContainerReader::ExtractPCH(
   // As a fallback, treat the buffer as a raw AST.
   StreamFile.init((const unsigned char *)Buffer.getBufferStart(),
                   (const unsigned char *)Buffer.getBufferEnd());
+  return;
 }