Remove some more unused headers from MachineFunction.h and friends.

[echristo]

Summary

Versus some of the earlier attempts here this is a little more difficult since most of these headers are still getting here transitively - but some grepping in the file convinced me that none of the things I think are here are here.

[dblaikie]

Sounds good to me.
How'd you test that the MachineMemOperand.h changes were OK? Looks like it doesn't have an implementation file, so I'm not sure it's included first in any file - which means it's harder to tell if removing headers from it is valid/keeps it standalone (since its inclusion context might be allowing it to get away without including necessary headers)

[echristo]

In D60741#1467705, @dblaikie wrote:

Sounds good to me.
How'd you test that the MachineMemOperand.h changes were OK? Looks like it doesn't have an implementation file, so I'm not sure it's included first in any file - which means it's harder to tell if removing headers from it is valid/keeps it standalone (since its inclusion context might be allowing it to get away without including necessary headers)

Basically grepping for Metadata and Inst things in the file itself. It's pretty short and I just read it. Always a possibility I missed something that's being gotten via transitive include though.

llvm/include/llvm/CodeGen/MachineFunction.h

 #include "llvm/ADT/SmallVector.h"
 #include "llvm/ADT/StringRef.h"
 #include "llvm/ADT/ilist.h"
 #include "llvm/ADT/iterator.h"
 #include "llvm/Analysis/EHPersonalities.h"
 #include "llvm/CodeGen/MachineBasicBlock.h"
 #include "llvm/CodeGen/MachineInstr.h"
 #include "llvm/CodeGen/MachineMemOperand.h"
-#include "llvm/IR/DebugLoc.h"
-#include "llvm/IR/Instructions.h"
-#include "llvm/IR/Metadata.h"
-#include "llvm/MC/MCSymbol.h"
 #include "llvm/Support/Allocator.h"
 #include "llvm/Support/ArrayRecycler.h"
 #include "llvm/Support/AtomicOrdering.h"
 #include "llvm/Support/Compiler.h"
 #include "llvm/Support/ErrorHandling.h"
 #include "llvm/Support/Recycler.h"
 #include <cassert>
 #include <cstdint>
 #include <memory>
 #include <utility>
 #include <vector>
 
 namespace llvm {
 
 class BasicBlock;
 class BlockAddress;
 class DataLayout;
+class DebugLoc;
 class DIExpression;
 class DILocalVariable;
 class DILocation;
 class Function;
 class GlobalValue;
 class LLVMTargetMachine;
 class MachineConstantPool;
 class MachineFrameInfo;
 class MachineFunction;
 class MachineJumpTableInfo;
 class MachineModuleInfo;
 class MachineRegisterInfo;
 class MCContext;
 class MCInstrDesc;
+class MCSymbol;
 class Pass;
 class PseudoSourceValueManager;
 class raw_ostream;
 class SlotIndexes;
 class TargetRegisterClass;
 class TargetSubtargetInfo;
 struct WasmEHFuncInfo;
 struct WinEHFuncInfo;

llvm/include/llvm/CodeGen/MachineMemOperand.h

 //===----------------------------------------------------------------------===//
 
 #ifndef LLVM_CODEGEN_MACHINEMEMOPERAND_H
 #define LLVM_CODEGEN_MACHINEMEMOPERAND_H
 
 #include "llvm/ADT/BitmaskEnum.h"
 #include "llvm/ADT/PointerUnion.h"
 #include "llvm/CodeGen/PseudoSourceValue.h"
-#include "llvm/IR/Instructions.h"
-#include "llvm/IR/Metadata.h"
 #include "llvm/IR/Value.h" // PointerLikeTypeTraits<Value*>
 #include "llvm/Support/AtomicOrdering.h"
 #include "llvm/Support/DataTypes.h"
 
 namespace llvm {
 
 class FoldingSetNodeID;
 class MDNode;

llvm/include/llvm/CodeGen/PseudoSourceValue.h

 //
 //===----------------------------------------------------------------------===//
 
 #ifndef LLVM_CODEGEN_PSEUDOSOURCEVALUE_H
 #define LLVM_CODEGEN_PSEUDOSOURCEVALUE_H
 
 #include "llvm/ADT/StringMap.h"
 #include "llvm/IR/GlobalValue.h"
-#include "llvm/IR/Value.h"
 #include "llvm/IR/ValueMap.h"
 #include <map>
 
 namespace llvm {
 
 class MachineFrameInfo;
 class MachineMemOperand;
 class raw_ostream;