runtime: remove use of swift/LLVM.h (NFC)

Rather than using the forward declaration for the LLVMSupport types,
expect to be able to use the full declaration.  Because these are
references in the implementation, there is no reason to use a forward
declaration as the full types need to be declared for use.  The LLVM
headers will provide the declaration and definition for the types.  This
is motivated by the desire to ensure that the LLVMSupport symbols are
properly namespaced to avoid ODR violations in the runtime.

Author: compnerd

stdlib/public/runtime/Casting.cpp

@@ -21,7 +21,6 @@
 #include "ExistentialMetadataImpl.h"
 #include "Private.h"
 #include "SwiftHashableSupport.h"
-#include "swift/Basic/LLVM.h"
 #include "swift/Basic/Lazy.h"
 #include "swift/Demangling/Demangler.h"
 #include "swift/Runtime/Config.h"

stdlib/public/runtime/Errors.cpp

@@ -40,7 +40,6 @@
 #include "swift/Runtime/Debug.h"
 #include "swift/Runtime/Mutex.h"
 #include "swift/Demangling/Demangle.h"
-#include "swift/Basic/LLVM.h"
 #include "llvm/ADT/StringRef.h"
 
 #if defined(_MSC_VER)
@@ -150,7 +149,7 @@ void swift::dumpStackTraceEntry(unsigned index, void *framePC,
   // library name here. Avoid using StringRef::rsplit because its definition
   // is not provided in the header so that it requires linking with
   // libSupport.a.
-  StringRef libraryName = StringRef(syminfo.fileName);
+  llvm::StringRef libraryName{syminfo.fileName};
   libraryName = libraryName.substr(libraryName.rfind('/')).substr(1);
 
   // Next we get the symbol name that we are going to use in our backtrace.

stdlib/public/runtime/Metadata.cpp

@@ -16,7 +16,6 @@
 
 #include "swift/Runtime/Metadata.h"
 #include "MetadataCache.h"
-#include "swift/Basic/LLVM.h"
 #include "swift/Basic/Lazy.h"
 #include "swift/Basic/Range.h"
 #include "swift/Demangling/Demangler.h"

stdlib/public/runtime/MetadataLookup.cpp

@@ -14,7 +14,6 @@
 //
 //===----------------------------------------------------------------------===//
 
-#include "swift/Basic/LLVM.h"
 #include "swift/Basic/Lazy.h"
 #include "swift/Demangling/Demangler.h"
 #include "swift/Demangling/TypeDecoder.h"

stdlib/public/runtime/ProtocolConformance.cpp

@@ -14,7 +14,6 @@
 //
 //===----------------------------------------------------------------------===//
 
-#include "swift/Basic/LLVM.h"
 #include "swift/Basic/Lazy.h"
 #include "swift/Demangling/Demangle.h"
 #include "swift/Runtime/Casting.h"

stdlib/public/runtime/SwiftObject.mm

@@ -24,7 +24,6 @@
 #include <objc/objc.h>
 #endif
 #include "llvm/ADT/StringRef.h"
-#include "swift/Basic/LLVM.h"
 #include "swift/Basic/Lazy.h"
 #include "swift/Runtime/Casting.h"
 #include "swift/Runtime/Heap.h"

stdlib/public/stubs/OptionalBridgingHelper.mm

@@ -14,7 +14,6 @@
 
 #if SWIFT_OBJC_INTEROP
 #include "swift/Basic/Lazy.h"
-#include "swift/Basic/LLVM.h"
 #include "swift/Runtime/Metadata.h"
 #include "swift/Runtime/Mutex.h"
 #include "swift/Runtime/ObjCBridge.h"