CommandFlags.h - remove unnecessary includes. NFC.

Replace with forward declarations and move necessary includes down to source files.

Exposes an implicit dependency on TargetMachine.h in llvm-opt-fuzzer.cpp

include/llvm/CodeGen/CommandFlags.h

@@ -16,18 +16,16 @@
 #include "llvm/ADT/StringExtras.h"
 #include "llvm/IR/Instructions.h"
 #include "llvm/IR/Intrinsics.h"
-#include "llvm/IR/Module.h"
 #include "llvm/MC/MCTargetOptionsCommandFlags.h"
-#include "llvm/MC/SubtargetFeature.h"
 #include "llvm/Support/CodeGen.h"
-#include "llvm/Support/CommandLine.h"
-#include "llvm/Support/Host.h"
-#include "llvm/Target/TargetMachine.h"
 #include "llvm/Target/TargetOptions.h"
 #include <string>
+#include <vector>
 
 namespace llvm {
 
+class Module;
+
 namespace codegen {
 
 std::string getMArch();

lib/CodeGen/CommandFlags.cpp

@@ -13,6 +13,10 @@
 //===----------------------------------------------------------------------===//
 
 #include "llvm/CodeGen/CommandFlags.h"
+#include "llvm/IR/Module.h"
+#include "llvm/MC/SubtargetFeature.h"
+#include "llvm/Support/CommandLine.h"
+#include "llvm/Support/Host.h"
 
 using namespace llvm;
 

tools/llvm-opt-fuzzer/llvm-opt-fuzzer.cpp

@@ -21,6 +21,7 @@
 #include "llvm/Support/SourceMgr.h"
 #include "llvm/Support/TargetRegistry.h"
 #include "llvm/Support/TargetSelect.h"
+#include "llvm/Target/TargetMachine.h"
 
 using namespace llvm;