Forward declare Optional<T> in STLExtras.h

WIP stats

include/llvm/ADT/STLExtras.h

@@ -16,8 +16,6 @@
 #ifndef LLVM_ADT_STLEXTRAS_H
 #define LLVM_ADT_STLEXTRAS_H
 
-#include "llvm/ADT/Optional.h"
-#include "llvm/ADT/SmallVector.h"
 #include "llvm/ADT/iterator.h"
 #include "llvm/ADT/iterator_range.h"
 #include "llvm/Config/abi-breaking.h"
@@ -42,6 +40,9 @@
 
 namespace llvm {
 
+template <typename T> class Optional;
+template <typename T, unsigned N> class SmallVector;
+
 // Only used by compiler if both template types are the same.  Useful when
 // using SFINAE to test for the existence of member functions.
 template <typename T, T> struct SameType;

include/llvm/ADT/StringSwitch.h

@@ -12,6 +12,7 @@
 #ifndef LLVM_ADT_STRINGSWITCH_H
 #define LLVM_ADT_STRINGSWITCH_H
 
+#include "llvm/ADT/Optional.h"
 #include "llvm/ADT/StringRef.h"
 #include "llvm/Support/Compiler.h"
 #include <cassert>

include/llvm/DebugInfo/DWARF/DWARFDebugFrame.h

@@ -10,9 +10,10 @@
 #define LLVM_DEBUGINFO_DWARF_DWARFDEBUGFRAME_H
 
 #include "llvm/ADT/ArrayRef.h"
-#include "llvm/ADT/iterator.h"
+#include "llvm/ADT/Optional.h"
 #include "llvm/ADT/SmallString.h"
 #include "llvm/ADT/Triple.h"
+#include "llvm/ADT/iterator.h"
 #include "llvm/DebugInfo/DWARF/DWARFDataExtractor.h"
 #include "llvm/DebugInfo/DWARF/DWARFExpression.h"
 #include "llvm/Support/Error.h"

include/llvm/Support/CachePruning.h

@@ -14,6 +14,7 @@
 #ifndef LLVM_SUPPORT_CACHE_PRUNING_H
 #define LLVM_SUPPORT_CACHE_PRUNING_H
 
+#include "llvm/ADT/Optional.h"
 #include "llvm/ADT/StringRef.h"
 #include <chrono>
 

include/llvm/Support/Error.h

@@ -14,6 +14,7 @@
 #define LLVM_SUPPORT_ERROR_H
 
 #include "llvm-c/Error.h"
+#include "llvm/ADT/Optional.h"
 #include "llvm/ADT/STLExtras.h"
 #include "llvm/ADT/SmallVector.h"
 #include "llvm/ADT/StringExtras.h"

include/llvm/Support/Format.h

@@ -23,6 +23,7 @@
 #define LLVM_SUPPORT_FORMAT_H
 
 #include "llvm/ADT/ArrayRef.h"
+#include "llvm/ADT/Optional.h"
 #include "llvm/ADT/STLExtras.h"
 #include "llvm/ADT/StringRef.h"
 #include "llvm/Support/DataTypes.h"

include/llvm/Support/Threading.h

@@ -15,6 +15,7 @@
 #define LLVM_SUPPORT_THREADING_H
 
 #include "llvm/ADT/FunctionExtras.h"
+#include "llvm/ADT/Optional.h"
 #include "llvm/ADT/SmallVector.h"
 #include "llvm/Config/llvm-config.h" // for LLVM_ON_UNIX
 #include "llvm/Support/Compiler.h"

lib/MC/MCInstrAnalysis.cpp

@@ -7,8 +7,8 @@
 //===----------------------------------------------------------------------===//
 
 #include "llvm/MC/MCInstrAnalysis.h"
-
 #include "llvm/ADT/APInt.h"
+#include "llvm/ADT/Optional.h"
 #include "llvm/MC/MCInst.h"
 #include "llvm/MC/MCInstrDesc.h"
 #include "llvm/MC/MCInstrInfo.h"

lib/Support/CrashRecoveryContext.cpp

@@ -7,6 +7,7 @@
 //===----------------------------------------------------------------------===//
 
 #include "llvm/Support/CrashRecoveryContext.h"
+#include "llvm/ADT/Optional.h"
 #include "llvm/Config/llvm-config.h"
 #include "llvm/Support/ErrorHandling.h"
 #include "llvm/Support/ManagedStatic.h"

lib/Support/DJB.cpp

@@ -12,6 +12,7 @@
 
 #include "llvm/Support/DJB.h"
 #include "llvm/ADT/ArrayRef.h"
+#include "llvm/ADT/Optional.h"
 #include "llvm/Support/Compiler.h"
 #include "llvm/Support/ConvertUTF.h"
 #include "llvm/Support/Unicode.h"