[NFC] Header cleanup

Removed some unused headers, replaced some headers with forward class declarations.

Found using simple scripts like this one:
clear && ack --cpp -l '#include "llvm/ADT/IndexedMap.h"' | xargs grep -L 'IndexedMap[<]' | xargs grep -n --color=auto 'IndexedMap'

Patch by Eugene Kosov <claprix@yandex.ru>

Differential Revision: http://reviews.llvm.org/D19219

From: Mehdi Amini <mehdi.amini@apple.com>
llvm-svn: 266595

llvm/include/llvm/ADT/Hashing.h

@@ -52,7 +52,6 @@
 #include <algorithm>
 #include <cassert>
 #include <cstring>
-#include <iterator>
 #include <string>
 #include <utility>
 

llvm/include/llvm/Analysis/AliasAnalysis.h

@@ -38,7 +38,6 @@
 #ifndef LLVM_ANALYSIS_ALIASANALYSIS_H
 #define LLVM_ANALYSIS_ALIASANALYSIS_H
 
-#include "llvm/ADT/DenseMap.h"
 #include "llvm/IR/CallSite.h"
 #include "llvm/IR/Metadata.h"
 #include "llvm/IR/PassManager.h"

llvm/include/llvm/Analysis/DependenceAnalysis.h

@@ -41,12 +41,12 @@
 #define LLVM_ANALYSIS_DEPENDENCEANALYSIS_H
 
 #include "llvm/ADT/SmallBitVector.h"
-#include "llvm/ADT/ArrayRef.h"
 #include "llvm/Analysis/AliasAnalysis.h"
 #include "llvm/IR/Instructions.h"
 #include "llvm/Pass.h"
 
 namespace llvm {
+template <typename T> class ArrayRef;
   class Loop;
   class LoopInfo;
   class ScalarEvolution;

llvm/include/llvm/Analysis/IteratedDominanceFrontier.h

@@ -24,7 +24,6 @@
 #ifndef LLVM_ANALYSIS_IDF_H
 #define LLVM_ANALYSIS_IDF_H
 
-#include "llvm/ADT/ArrayRef.h"
 #include "llvm/ADT/DenseMap.h"
 #include "llvm/ADT/SmallPtrSet.h"
 #include "llvm/ADT/SmallVector.h"

llvm/include/llvm/Analysis/MemoryLocation.h

@@ -16,7 +16,7 @@
 #ifndef LLVM_ANALYSIS_MEMORYLOCATION_H
 #define LLVM_ANALYSIS_MEMORYLOCATION_H
 
-#include "llvm/ADT/DenseMap.h"
+#include "llvm/ADT/DenseMapInfo.h"
 #include "llvm/IR/CallSite.h"
 #include "llvm/IR/Metadata.h"
 

llvm/include/llvm/Analysis/RegionInfoImpl.h

@@ -18,7 +18,6 @@
 #include "llvm/Analysis/PostDominators.h"
 #include "llvm/Analysis/RegionInfo.h"
 #include "llvm/Analysis/RegionIterator.h"
-#include "llvm/Support/CommandLine.h"
 #include "llvm/Support/Debug.h"
 #include "llvm/Support/ErrorHandling.h"
 #include <algorithm>

llvm/include/llvm/Analysis/ScalarEvolution.h

@@ -26,7 +26,6 @@
 #include "llvm/ADT/SetVector.h"
 #include "llvm/Analysis/LoopInfo.h"
 #include "llvm/IR/ConstantRange.h"
-#include "llvm/IR/Function.h"
 #include "llvm/IR/Instructions.h"
 #include "llvm/IR/Operator.h"
 #include "llvm/IR/PassManager.h"
@@ -35,7 +34,6 @@
 #include "llvm/Pass.h"
 #include "llvm/Support/Allocator.h"
 #include "llvm/Support/DataTypes.h"
-#include <map>
 
 namespace llvm {
   class APInt;
@@ -55,6 +53,7 @@ namespace llvm {
   class SCEVExpander;
   class SCEVPredicate;
   class SCEVUnknown;
+  class Function;
 
   template <> struct FoldingSetTrait<SCEV>;
   template <> struct FoldingSetTrait<SCEVPredicate>;

llvm/include/llvm/Analysis/TargetLibraryInfo.h

@@ -11,7 +11,6 @@
 #define LLVM_ANALYSIS_TARGETLIBRARYINFO_H
 
 #include "llvm/ADT/DenseMap.h"
-#include "llvm/ADT/ArrayRef.h"
 #include "llvm/ADT/Optional.h"
 #include "llvm/ADT/Triple.h"
 #include "llvm/IR/Function.h"
@@ -20,6 +19,8 @@
 #include "llvm/Pass.h"
 
 namespace llvm {
+template <typename T> class ArrayRef;
+
 /// Describes a possible vectorization of a function.
 /// Function 'VectorFnName' is equivalent to 'ScalarFnName' vectorized
 /// by a factor 'VectorizationFactor'.

llvm/include/llvm/Analysis/ValueTracking.h

@@ -15,12 +15,12 @@
 #ifndef LLVM_ANALYSIS_VALUETRACKING_H
 #define LLVM_ANALYSIS_VALUETRACKING_H
 
-#include "llvm/ADT/ArrayRef.h"
 #include "llvm/IR/ConstantRange.h"
 #include "llvm/IR/Instruction.h"
 #include "llvm/Support/DataTypes.h"
 
 namespace llvm {
+template <typename T> class ArrayRef;
   class APInt;
   class AddOperator;
   class AssumptionCache;

llvm/include/llvm/Analysis/VectorUtils.h

@@ -14,7 +14,6 @@
 #ifndef LLVM_TRANSFORMS_UTILS_VECTORUTILS_H
 #define LLVM_TRANSFORMS_UTILS_VECTORUTILS_H
 
-#include "llvm/ADT/ArrayRef.h"
 #include "llvm/ADT/MapVector.h"
 #include "llvm/Analysis/TargetLibraryInfo.h"
 #include "llvm/IR/IntrinsicInst.h"
@@ -22,6 +21,7 @@
 
 namespace llvm {
 
+template <typename T> class ArrayRef;
 struct DemandedBits;
 class GetElementPtrInst;
 class Loop;

llvm/include/llvm/CodeGen/DIE.h

@@ -20,7 +20,6 @@
 #include "llvm/ADT/SmallVector.h"
 #include "llvm/CodeGen/DwarfStringPoolEntry.h"
 #include "llvm/Support/Dwarf.h"
-#include <vector>
 
 namespace llvm {
 class AsmPrinter;

llvm/include/llvm/CodeGen/FaultMaps.h

@@ -10,7 +10,6 @@
 #ifndef LLVM_CODEGEN_FAULTMAPS_H
 #define LLVM_CODEGEN_FAULTMAPS_H
 
-#include "llvm/ADT/DenseMap.h"
 #include "llvm/MC/MCSymbol.h"
 #include "llvm/Support/Endian.h"
 #include "llvm/Support/Format.h"

llvm/include/llvm/CodeGen/GlobalISel/Types.h

@@ -16,7 +16,6 @@
 #define LLVM_CODEGEN_GLOBALISEL_TYPES_H
 
 #include "llvm/ADT/DenseMap.h"
-#include "llvm/ADT/SmallVector.h"
 #include "llvm/IR/Value.h"
 
 namespace llvm {

llvm/include/llvm/CodeGen/LiveIntervalAnalysis.h

@@ -31,7 +31,6 @@
 #include "llvm/Support/CommandLine.h"
 #include "llvm/Target/TargetRegisterInfo.h"
 #include <cmath>
-#include <iterator>
 
 namespace llvm {
 

llvm/include/llvm/CodeGen/MIRParser/MIRParser.h

@@ -18,7 +18,6 @@
 #ifndef LLVM_CODEGEN_MIRPARSER_MIRPARSER_H
 #define LLVM_CODEGEN_MIRPARSER_MIRPARSER_H
 
-#include "llvm/ADT/StringRef.h"
 #include "llvm/CodeGen/MachineFunctionInitializer.h"
 #include "llvm/IR/Module.h"
 #include "llvm/Support/MemoryBuffer.h"
@@ -26,6 +25,7 @@
 
 namespace llvm {
 
+class StringRef;
 class MIRParserImpl;
 class SMDiagnostic;
 

llvm/include/llvm/CodeGen/MachineInstr.h

@@ -16,10 +16,8 @@
 #ifndef LLVM_CODEGEN_MACHINEINSTR_H
 #define LLVM_CODEGEN_MACHINEINSTR_H
 
-#include "llvm/ADT/ArrayRef.h"
 #include "llvm/ADT/DenseMapInfo.h"
 #include "llvm/ADT/STLExtras.h"
-#include "llvm/ADT/StringRef.h"
 #include "llvm/ADT/ilist.h"
 #include "llvm/ADT/ilist_node.h"
 #include "llvm/ADT/iterator_range.h"
@@ -33,6 +31,8 @@
 
 namespace llvm {
 
+class StringRef;
+template <typename T> class ArrayRef;
 template <typename T> class SmallVectorImpl;
 class DILocalVariable;
 class DIExpression;

llvm/include/llvm/CodeGen/MachineSSAUpdater.h

@@ -14,7 +14,6 @@
 #ifndef LLVM_CODEGEN_MACHINESSAUPDATER_H
 #define LLVM_CODEGEN_MACHINESSAUPDATER_H
 
-#include "llvm/Support/Allocator.h"
 #include "llvm/Support/Compiler.h"
 
 namespace llvm {

llvm/include/llvm/CodeGen/PBQP/Graph.h

@@ -15,12 +15,7 @@
 #ifndef LLVM_CODEGEN_PBQP_GRAPH_H
 #define LLVM_CODEGEN_PBQP_GRAPH_H
 
-#include "llvm/ADT/ilist.h"
-#include "llvm/ADT/ilist_node.h"
 #include "llvm/Support/Debug.h"
-#include <list>
-#include <map>
-#include <set>
 #include <vector>
 
 namespace llvm {

llvm/include/llvm/CodeGen/ParallelCG.h

@@ -14,7 +14,6 @@
 #ifndef LLVM_CODEGEN_PARALLELCG_H
 #define LLVM_CODEGEN_PARALLELCG_H
 
-#include "llvm/ADT/ArrayRef.h"
 #include "llvm/Support/CodeGen.h"
 #include "llvm/Target/TargetMachine.h"
 
@@ -22,6 +21,7 @@
 
 namespace llvm {
 
+template <typename T> class ArrayRef;
 class Module;
 class TargetOptions;
 class raw_pwrite_stream;

llvm/include/llvm/CodeGen/RegAllocPBQP.h

@@ -21,6 +21,7 @@
 #include "llvm/CodeGen/PBQP/ReductionRules.h"
 #include "llvm/CodeGen/PBQPRAConstraint.h"
 #include "llvm/Support/ErrorHandling.h"
+#include <set>
 
 namespace llvm {
 

llvm/include/llvm/CodeGen/StackMaps.h

@@ -14,8 +14,6 @@
 #include "llvm/ADT/SmallVector.h"
 #include "llvm/CodeGen/MachineInstr.h"
 #include "llvm/MC/MCSymbol.h"
-#include "llvm/Support/Debug.h"
-#include <map>
 #include <vector>
 
 namespace llvm {

llvm/include/llvm/CodeGen/TargetLoweringObjectFileImpl.h

@@ -15,7 +15,6 @@
 #ifndef LLVM_CODEGEN_TARGETLOWERINGOBJECTFILEIMPL_H
 #define LLVM_CODEGEN_TARGETLOWERINGOBJECTFILEIMPL_H
 
-#include "llvm/ADT/StringRef.h"
 #include "llvm/MC/SectionKind.h"
 #include "llvm/Target/TargetLoweringObjectFile.h"
 

llvm/include/llvm/DebugInfo/CodeView/TypeSymbolEmitter.h

@@ -10,11 +10,12 @@
 #ifndef LLVM_DEBUGINFO_CODEVIEW_TYPESYMBOLEMITTER_H
 #define LLVM_DEBUGINFO_CODEVIEW_TYPESYMBOLEMITTER_H
 
-#include "llvm/ADT/StringRef.h"
 #include "llvm/DebugInfo/CodeView/CodeView.h"
 #include "llvm/DebugInfo/CodeView/TypeIndex.h"
 
 namespace llvm {
+class StringRef;
+
 namespace codeview {
 
 class TypeSymbolEmitter {

llvm/include/llvm/DebugInfo/CodeView/TypeTableBuilder.h

@@ -10,13 +10,15 @@
 #ifndef LLVM_DEBUGINFO_CODEVIEW_TYPETABLEBUILDER_H
 #define LLVM_DEBUGINFO_CODEVIEW_TYPETABLEBUILDER_H
 
-#include "llvm/ADT/StringRef.h"
 #include "llvm/DebugInfo/CodeView/CodeView.h"
 #include "llvm/DebugInfo/CodeView/TypeIndex.h"
 #include "llvm/DebugInfo/CodeView/TypeRecord.h"
 #include "llvm/Support/Compiler.h"
 
 namespace llvm {
+
+class StringRef;
+
 namespace codeview {
 
 class FieldListRecordBuilder;

llvm/include/llvm/DebugInfo/DIContext.h

@@ -15,7 +15,6 @@
 #ifndef LLVM_DEBUGINFO_DICONTEXT_H
 #define LLVM_DEBUGINFO_DICONTEXT_H
 
-#include "llvm/ADT/DenseMap.h"
 #include "llvm/ADT/SmallVector.h"
 #include "llvm/Object/ObjectFile.h"
 #include "llvm/Object/RelocVisitor.h"

llvm/include/llvm/DebugInfo/DWARF/DWARFContext.h

@@ -22,7 +22,6 @@
 #include "llvm/DebugInfo/DWARF/DWARFDebugRangeList.h"
 #include "llvm/DebugInfo/DWARF/DWARFSection.h"
 #include "llvm/DebugInfo/DWARF/DWARFTypeUnit.h"
-#include <vector>
 
 namespace llvm {
 

llvm/include/llvm/DebugInfo/DWARF/DWARFDebugAbbrev.h

@@ -11,7 +11,6 @@
 #define LLVM_LIB_DEBUGINFO_DWARFDEBUGABBREV_H
 
 #include "llvm/DebugInfo/DWARF/DWARFAbbreviationDeclaration.h"
-#include <list>
 #include <map>
 #include <vector>
 

llvm/include/llvm/DebugInfo/DWARF/DWARFDebugMacro.h

@@ -11,7 +11,6 @@
 #define LLVM_DEBUGINFO_DWARF_DWARFDEBUGMACRO_H
 
 #include "llvm/ADT/SmallVector.h"
-#include "llvm/ADT/StringRef.h"
 #include "llvm/Support/DataExtractor.h"
 #include "llvm/Support/Dwarf.h"
 

llvm/include/llvm/DebugInfo/DWARF/DWARFFormValue.h

@@ -10,12 +10,12 @@
 #ifndef LLVM_DEBUGINFO_DWARFFORMVALUE_H
 #define LLVM_DEBUGINFO_DWARFFORMVALUE_H
 
-#include "llvm/ADT/ArrayRef.h"
 #include "llvm/ADT/Optional.h"
 #include "llvm/Support/DataExtractor.h"
 
 namespace llvm {
 
+template <typename T> class ArrayRef;
 class DWARFUnit;
 class raw_ostream;
 

llvm/include/llvm/DebugInfo/PDB/DIA/DIASession.h

@@ -11,10 +11,11 @@
 #define LLVM_DEBUGINFO_PDB_DIA_DIASESSION_H
 
 #include "DIASupport.h"
-#include "llvm/ADT/StringRef.h"
 #include "llvm/DebugInfo/PDB/IPDBSession.h"
 
 namespace llvm {
+class StringRef;
+
 class DIASession : public IPDBSession {
 public:
   explicit DIASession(CComPtr<IDiaSession> DiaSession);

llvm/include/llvm/DebugInfo/PDB/PDBSymbol.h

@@ -15,9 +15,7 @@
 #include "PDBExtras.h"
 #include "PDBTypes.h"
 #include "llvm/ADT/STLExtras.h"
-#include "llvm/ADT/StringRef.h"
 #include "llvm/Support/Casting.h"
-#include <unordered_map>
 
 #define FORWARD_SYMBOL_METHOD(MethodName)                                      \
   auto MethodName() const->decltype(RawSymbol->MethodName()) {                 \
@@ -26,6 +24,7 @@
 
 namespace llvm {
 
+class StringRef;
 class IPDBRawSymbol;
 class raw_ostream;
 

llvm/include/llvm/DebugInfo/PDB/PDBSymbolAnnotation.h

@@ -11,7 +11,6 @@
 
 #include "PDBSymbol.h"
 #include "PDBTypes.h"
-#include <string>
 
 namespace llvm {
 

llvm/include/llvm/DebugInfo/PDB/PDBSymbolBlock.h

@@ -11,7 +11,6 @@
 
 #include "PDBSymbol.h"
 #include "PDBTypes.h"
-#include <string>
 
 namespace llvm {
 

llvm/include/llvm/DebugInfo/PDB/PDBSymbolExe.h

@@ -12,7 +12,6 @@
 
 #include "PDBSymbol.h"
 #include "PDBTypes.h"
-#include <string>
 
 namespace llvm {
 

llvm/include/llvm/DebugInfo/PDB/PDBSymbolThunk.h

@@ -12,7 +12,6 @@
 
 #include "PDBSymbol.h"
 #include "PDBTypes.h"
-#include <string>
 
 namespace llvm {
 

llvm/include/llvm/DebugInfo/Symbolize/SymbolizableModule.h

@@ -14,8 +14,6 @@
 #define LLVM_DEBUGINFO_SYMBOLIZE_SYMBOLIZABLEMODULE_H
 
 #include "llvm/DebugInfo/DIContext.h"
-#include <memory>
-#include <string>
 
 namespace llvm {
 namespace object {

llvm/include/llvm/ExecutionEngine/Orc/IndirectionUtils.h

@@ -16,14 +16,12 @@
 
 #include "JITSymbol.h"
 #include "LambdaResolver.h"
-#include "llvm/ADT/DenseSet.h"
 #include "llvm/ExecutionEngine/RuntimeDyld.h"
 #include "llvm/IR/IRBuilder.h"
 #include "llvm/IR/Mangler.h"
 #include "llvm/IR/Module.h"
-#include "llvm/Transforms/Utils/ValueMapper.h"
 #include "llvm/Support/Process.h"
-#include <sstream>
+#include "llvm/Transforms/Utils/ValueMapper.h"
 
 namespace llvm {
 namespace orc {

llvm/include/llvm/ExecutionEngine/Orc/LambdaResolver.h

@@ -18,7 +18,6 @@
 #include "llvm/ADT/STLExtras.h"
 #include "llvm/ExecutionEngine/RuntimeDyld.h"
 #include <memory>
-#include <vector>
 
 namespace llvm {
 namespace orc {

llvm/include/llvm/ExecutionEngine/RTDyldMemoryManager.h

@@ -16,7 +16,6 @@
 
 #include "RuntimeDyld.h"
 #include "llvm-c/ExecutionEngine.h"
-#include "llvm/ADT/StringRef.h"
 #include "llvm/Support/CBindingWrapping.h"
 #include "llvm/Support/Memory.h"
 

llvm/include/llvm/ExecutionEngine/RuntimeDyld.h

@@ -16,15 +16,16 @@
 
 #include "JITSymbolFlags.h"
 #include "llvm/ADT/STLExtras.h"
-#include "llvm/ADT/StringRef.h"
+#include "llvm/DebugInfo/DIContext.h"
 #include "llvm/Object/ObjectFile.h"
 #include "llvm/Support/Memory.h"
-#include "llvm/DebugInfo/DIContext.h"
 #include <map>
 #include <memory>
 
 namespace llvm {
 
+class StringRef;
+
 namespace object {
   class ObjectFile;
   template <typename T> class OwningBinary;

llvm/include/llvm/ExecutionEngine/RuntimeDyldChecker.h

@@ -10,11 +10,11 @@
 #ifndef LLVM_EXECUTIONENGINE_RUNTIMEDYLDCHECKER_H
 #define LLVM_EXECUTIONENGINE_RUNTIMEDYLDCHECKER_H
 
-#include "llvm/ADT/StringRef.h"
 #include <memory>
 
 namespace llvm {
 
+class StringRef;
 class MCDisassembler;
 class MemoryBuffer;
 class MCInstPrinter;

llvm/include/llvm/IR/IRBuilder.h

@@ -16,7 +16,6 @@
 #define LLVM_IR_IRBUILDER_H
 
 #include "llvm/ADT/ArrayRef.h"
-#include "llvm/ADT/StringRef.h"
 #include "llvm/ADT/Twine.h"
 #include "llvm/IR/BasicBlock.h"
 #include "llvm/IR/ConstantFolder.h"
@@ -31,6 +30,7 @@
 #include "llvm/Support/CBindingWrapping.h"
 
 namespace llvm {
+class StringRef;
 class MDNode;
 
 /// \brief This provides the default implementation of the IRBuilder

llvm/include/llvm/IR/LegacyPassManagers.h

@@ -19,7 +19,6 @@
 #include "llvm/ADT/SmallPtrSet.h"
 #include "llvm/ADT/SmallVector.h"
 #include "llvm/Pass.h"
-#include <map>
 #include <vector>
 
 //===----------------------------------------------------------------------===//

llvm/include/llvm/IR/Use.h

@@ -28,7 +28,6 @@
 #include "llvm/ADT/PointerIntPair.h"
 #include "llvm/Support/CBindingWrapping.h"
 #include <cstddef>
-#include <iterator>
 
 namespace llvm {
 

llvm/include/llvm/IRReader/IRReader.h

@@ -15,11 +15,12 @@
 #ifndef LLVM_IRREADER_IRREADER_H
 #define LLVM_IRREADER_IRREADER_H
 
-#include "llvm/Support/MemoryBuffer.h"
-#include <string>
+#include <memory>
 
 namespace llvm {
 
+class StringRef;
+class MemoryBufferRef;
 class Module;
 class SMDiagnostic;
 class LLVMContext;

llvm/include/llvm/LTO/LTOCodeGenerator.h

@@ -36,7 +36,6 @@
 #define LLVM_LTO_LTOCODEGENERATOR_H
 
 #include "llvm-c/lto.h"
-#include "llvm/ADT/ArrayRef.h"
 #include "llvm/ADT/SmallPtrSet.h"
 #include "llvm/ADT/StringMap.h"
 #include "llvm/ADT/StringSet.h"
@@ -48,6 +47,7 @@
 #include <vector>
 
 namespace llvm {
+template <typename T> class ArrayRef;
   class LLVMContext;
   class DiagnosticInfo;
   class Linker;

llvm/include/llvm/LTO/ThinLTOCodeGenerator.h

@@ -17,7 +17,6 @@
 #define LLVM_LTO_THINLTOCODEGENERATOR_H
 
 #include "llvm-c/lto.h"
-#include "llvm/ADT/StringRef.h"
 #include "llvm/ADT/StringSet.h"
 #include "llvm/ADT/Triple.h"
 #include "llvm/Support/CodeGen.h"
@@ -27,6 +26,7 @@
 #include <string>
 
 namespace llvm {
+class StringRef;
 class ModuleSummaryIndex;
 class LLVMContext;
 class TargetMachine;

llvm/include/llvm/LibDriver/LibDriver.h

@@ -15,12 +15,10 @@
 #ifndef LLVM_LIBDRIVER_LIBDRIVER_H
 #define LLVM_LIBDRIVER_LIBDRIVER_H
 
-#include "llvm/ADT/ArrayRef.h"
-
 namespace llvm {
+template <typename T> class ArrayRef;
 
-int libDriverMain(llvm::ArrayRef<const char*> ARgs);
-
+int libDriverMain(ArrayRef<const char *> ARgs);
 }
 
 #endif

llvm/include/llvm/MC/MCAsmBackend.h

@@ -29,7 +29,7 @@ class MCRelaxableFragment;
 class MCObjectWriter;
 class MCSection;
 class MCValue;
-class raw_ostream;
+class raw_pwrite_stream;
 
 /// Generic interface to target specific assembler backends.
 class MCAsmBackend {

llvm/include/llvm/MC/MCDisassembler/MCDisassembler.h

@@ -10,12 +10,12 @@
 #define LLVM_MC_MCDISASSEMBLER_MCDISASSEMBLER_H
 
 #include "llvm-c/Disassembler.h"
-#include "llvm/ADT/ArrayRef.h"
 #include "llvm/MC/MCDisassembler/MCSymbolizer.h"
 #include "llvm/Support/DataTypes.h"
 
 namespace llvm {
 
+template <typename T> class ArrayRef;
 class MCInst;
 class MCSubtargetInfo;
 class raw_ostream;

llvm/include/llvm/MC/MCDwarf.h

@@ -15,20 +15,18 @@
 #ifndef LLVM_MC_MCDWARF_H
 #define LLVM_MC_MCDWARF_H
 
-#include "llvm/ADT/ArrayRef.h"
 #include "llvm/ADT/MapVector.h"
 #include "llvm/ADT/StringMap.h"
 #include "llvm/ADT/StringRef.h"
 #include "llvm/MC/MCSection.h"
-#include "llvm/Support/Compiler.h"
 #include "llvm/Support/Dwarf.h"
-#include "llvm/Support/raw_ostream.h"
-#include <map>
 #include <string>
 #include <utility>
 #include <vector>
 
 namespace llvm {
+template <typename T> class ArrayRef;
+class raw_ostream;
 class MCAsmBackend;
 class MCContext;
 class MCObjectStreamer;

llvm/include/llvm/MC/MCELFStreamer.h

@@ -15,7 +15,6 @@
 #include "llvm/MC/MCObjectStreamer.h"
 #include "llvm/MC/SectionKind.h"
 #include "llvm/Support/DataTypes.h"
-#include <vector>
 
 namespace llvm {
 class MCAsmBackend;

llvm/include/llvm/MC/MCInstPrinter.h

@@ -10,11 +10,11 @@
 #ifndef LLVM_MC_MCINSTPRINTER_H
 #define LLVM_MC_MCINSTPRINTER_H
 
-#include "llvm/ADT/ArrayRef.h"
 #include "llvm/Support/DataTypes.h"
 #include "llvm/Support/Format.h"
 
 namespace llvm {
+template <typename T> class ArrayRef;
 class MCInst;
 class raw_ostream;
 class MCAsmInfo;

llvm/include/llvm/MC/MCMachObjectWriter.h

@@ -11,7 +11,6 @@
 #define LLVM_MC_MCMACHOBJECTWRITER_H
 
 #include "llvm/ADT/DenseMap.h"
-#include "llvm/ADT/SmallString.h"
 #include "llvm/MC/MCExpr.h"
 #include "llvm/MC/MCSection.h"
 #include "llvm/MC/MCObjectWriter.h"

llvm/include/llvm/MC/MCSection.h

@@ -15,7 +15,6 @@
 #define LLVM_MC_MCSECTION_H
 
 #include "llvm/ADT/SmallVector.h"
-#include "llvm/ADT/StringRef.h"
 #include "llvm/ADT/ilist.h"
 #include "llvm/ADT/ilist_node.h"
 #include "llvm/MC/MCFragment.h"

llvm/include/llvm/MC/MCSubtargetInfo.h

@@ -14,6 +14,7 @@
 #ifndef LLVM_MC_MCSUBTARGETINFO_H
 #define LLVM_MC_MCSUBTARGETINFO_H
 
+#include "llvm/ADT/ArrayRef.h"
 #include "llvm/MC/MCInstrItineraries.h"
 #include "llvm/MC/SubtargetFeature.h"
 #include <string>

llvm/include/llvm/MC/MCWin64EH.h

@@ -17,7 +17,6 @@
 
 #include "llvm/MC/MCWinEH.h"
 #include "llvm/Support/Win64EH.h"
-#include <vector>
 
 namespace llvm {
 class MCStreamer;

llvm/include/llvm/MC/SubtargetFeature.h

@@ -18,12 +18,13 @@
 #ifndef LLVM_MC_SUBTARGETFEATURE_H
 #define LLVM_MC_SUBTARGETFEATURE_H
 
-#include "llvm/ADT/ArrayRef.h"
 #include "llvm/ADT/Triple.h"
 #include "llvm/Support/DataTypes.h"
 #include <bitset>
+#include <vector>
 
 namespace llvm {
+template <typename T> class ArrayRef;
   class raw_ostream;
   class StringRef;
 

llvm/include/llvm/Object/ELFObjectFile.h

@@ -14,10 +14,7 @@
 #ifndef LLVM_OBJECT_ELFOBJECTFILE_H
 #define LLVM_OBJECT_ELFOBJECTFILE_H
 
-#include "llvm/ADT/DenseMap.h"
-#include "llvm/ADT/PointerIntPair.h"
 #include "llvm/ADT/SmallVector.h"
-#include "llvm/ADT/StringSwitch.h"
 #include "llvm/ADT/Triple.h"
 #include "llvm/Object/ELF.h"
 #include "llvm/Object/ObjectFile.h"
@@ -26,10 +23,8 @@
 #include "llvm/Support/Endian.h"
 #include "llvm/Support/ErrorHandling.h"
 #include "llvm/Support/MemoryBuffer.h"
-#include "llvm/Support/raw_ostream.h"
 #include <algorithm>
 #include <cctype>
-#include <limits>
 #include <utility>
 
 namespace llvm {

llvm/include/llvm/Object/MachOUniversal.h

@@ -14,7 +14,6 @@
 #ifndef LLVM_OBJECT_MACHOUNIVERSAL_H
 #define LLVM_OBJECT_MACHOUNIVERSAL_H
 
-#include "llvm/ADT/StringRef.h"
 #include "llvm/ADT/Triple.h"
 #include "llvm/ADT/iterator_range.h"
 #include "llvm/Object/Archive.h"
@@ -24,6 +23,8 @@
 #include "llvm/Support/MachO.h"
 
 namespace llvm {
+class StringRef;
+
 namespace object {
 
 class MachOUniversalBinary : public Binary {

llvm/include/llvm/Object/ObjectFile.h

@@ -21,7 +21,6 @@
 #include "llvm/Support/FileSystem.h"
 #include "llvm/Support/MemoryBuffer.h"
 #include <cstring>
-#include <vector>
 
 namespace llvm {
 namespace object {

llvm/include/llvm/Object/RelocVisitor.h

@@ -16,7 +16,6 @@
 #ifndef LLVM_OBJECT_RELOCVISITOR_H
 #define LLVM_OBJECT_RELOCVISITOR_H
 
-#include "llvm/ADT/StringRef.h"
 #include "llvm/Object/COFF.h"
 #include "llvm/Object/ELFObjectFile.h"
 #include "llvm/Object/MachO.h"

llvm/include/llvm/Object/StackMapParser.h

@@ -11,9 +11,7 @@
 #define LLVM_CODEGEN_STACKMAPPARSER_H
 
 #include "llvm/ADT/ArrayRef.h"
-#include "llvm/Support/Debug.h"
 #include "llvm/Support/Endian.h"
-#include <map>
 #include <vector>
 
 namespace llvm {

llvm/include/llvm/PassAnalysisSupport.h

@@ -20,11 +20,11 @@
 #define LLVM_PASSANALYSISSUPPORT_H
 
 #include "llvm/ADT/SmallVector.h"
-#include "llvm/ADT/StringRef.h"
 #include "llvm/Pass.h"
 #include <vector>
 
 namespace llvm {
+class StringRef;
 
 //===----------------------------------------------------------------------===//
 /// Represent the analysis usage information of a pass.  This tracks analyses

llvm/include/llvm/PassRegistry.h

@@ -20,7 +20,6 @@
 #include "llvm/ADT/DenseMap.h"
 #include "llvm/ADT/SmallPtrSet.h"
 #include "llvm/ADT/StringMap.h"
-#include "llvm/ADT/StringRef.h"
 #include "llvm/PassInfo.h"
 #include "llvm/Support/CBindingWrapping.h"
 #include "llvm/Support/RWMutex.h"
@@ -28,6 +27,7 @@
 
 namespace llvm {
 
+class StringRef;
 class PassInfo;
 struct PassRegistrationListener;
 

llvm/include/llvm/PassSupport.h

@@ -26,8 +26,6 @@
 #include "llvm/PassInfo.h"
 #include "llvm/PassRegistry.h"
 #include "llvm/Support/Atomic.h"
-#include "llvm/Support/Compiler.h"
-#include <vector>
 
 namespace llvm {
 

llvm/include/llvm/Passes/PassBuilder.h

@@ -16,12 +16,12 @@
 #ifndef LLVM_PASSES_PASSBUILDER_H
 #define LLVM_PASSES_PASSBUILDER_H
 
-#include "llvm/ADT/StringRef.h"
 #include "llvm/Analysis/CGSCCPassManager.h"
 #include "llvm/Analysis/LoopPassManager.h"
 #include "llvm/IR/PassManager.h"
 
 namespace llvm {
+class StringRef;
 class AAManager;
 class TargetMachine;
 

llvm/include/llvm/ProfileData/InstrProf.h

@@ -30,7 +30,6 @@
 #include "llvm/Support/MathExtras.h"
 #include <cstdint>
 #include <list>
-#include <map>
 #include <system_error>
 #include <vector>
 

llvm/include/llvm/ProfileData/ProfileCommon.h

@@ -15,7 +15,6 @@
 #ifndef LLVM_PROFILEDATA_PROFILE_COMMON_H
 #define LLVM_PROFILEDATA_PROFILE_COMMON_H
 
-#include "llvm/ADT/APInt.h"
 #include <cstdint>
 #include <functional>
 #include <map>

llvm/include/llvm/Support/ConvertUTF.h

@@ -180,10 +180,13 @@ unsigned getNumBytesForUTF8(UTF8 firstByte);
 /*************************************************************************/
 /* Below are LLVM-specific wrappers of the functions above. */
 
-#include "llvm/ADT/ArrayRef.h"
-#include "llvm/ADT/StringRef.h"
+#include <string>
+#include <cstddef>
 
 namespace llvm {
+template <typename T> class ArrayRef;
+template <typename T> class SmallVectorImpl;
+class StringRef;
 
 /**
  * Convert an UTF8 StringRef to UTF8, UTF16, or UTF32 depending on

llvm/include/llvm/Support/CrashRecoveryContext.h

@@ -11,7 +11,6 @@
 #define LLVM_SUPPORT_CRASHRECOVERYCONTEXT_H
 
 #include "llvm/ADT/STLExtras.h"
-#include <string>
 
 namespace llvm {
 class CrashRecoveryContextCleanup;

llvm/include/llvm/Support/Dwarf.h

@@ -20,11 +20,11 @@
 #ifndef LLVM_SUPPORT_DWARF_H
 #define LLVM_SUPPORT_DWARF_H
 
-#include "llvm/ADT/StringRef.h"
 #include "llvm/Support/Compiler.h"
 #include "llvm/Support/DataTypes.h"
 
 namespace llvm {
+class StringRef;
 
 namespace dwarf {
 

llvm/include/llvm/Support/ErrorHandling.h

@@ -15,11 +15,11 @@
 #ifndef LLVM_SUPPORT_ERRORHANDLING_H
 #define LLVM_SUPPORT_ERRORHANDLING_H
 
-#include "llvm/ADT/StringRef.h"
 #include "llvm/Support/Compiler.h"
 #include <string>
 
 namespace llvm {
+class StringRef;
   class Twine;
 
   /// An error handler callback.

llvm/include/llvm/Support/JamCRC.h

@@ -27,10 +27,11 @@
 #ifndef LLVM_SUPPORT_JAMCRC_H
 #define LLVM_SUPPORT_JAMCRC_H
 
-#include "llvm/ADT/ArrayRef.h"
 #include "llvm/Support/DataTypes.h"
 
 namespace llvm {
+template <typename T> class ArrayRef;
+
 class JamCRC {
 public:
   JamCRC(uint32_t Init = 0xFFFFFFFFU) : CRC(Init) {}

llvm/include/llvm/Support/Locale.h

@@ -1,9 +1,9 @@
 #ifndef LLVM_SUPPORT_LOCALE_H
 #define LLVM_SUPPORT_LOCALE_H
 
-#include "llvm/ADT/StringRef.h"
-
 namespace llvm {
+class StringRef;
+
 namespace sys {
 namespace locale {
 

llvm/include/llvm/Support/LockFileManager.h

@@ -11,11 +11,12 @@
 
 #include "llvm/ADT/Optional.h"
 #include "llvm/ADT/SmallString.h"
-#include "llvm/ADT/StringRef.h"
 #include <system_error>
 #include <utility> // for std::pair
 
 namespace llvm {
+class StringRef;
+
 /// \brief Class that manages the creation of a lock file to aid
 /// implicit coordination between different processes.
 ///

llvm/include/llvm/Support/MD5.h

@@ -28,12 +28,12 @@
 #ifndef LLVM_SUPPORT_MD5_H
 #define LLVM_SUPPORT_MD5_H
 
-#include "llvm/ADT/ArrayRef.h"
 #include "llvm/ADT/SmallString.h"
 #include "llvm/Support/DataTypes.h"
 #include "llvm/Support/Endian.h"
 
 namespace llvm {
+template <typename T> class ArrayRef;
 
 class MD5 {
   // Any 32-bit or wider unsigned integer data type will do.

llvm/include/llvm/Support/MathExtras.h

@@ -19,6 +19,7 @@
 #include <cassert>
 #include <cstring>
 #include <type_traits>
+#include <limits>
 
 #ifdef _MSC_VER
 #include <intrin.h>

llvm/include/llvm/Support/Path.h

@@ -16,7 +16,6 @@
 #ifndef LLVM_SUPPORT_PATH_H
 #define LLVM_SUPPORT_PATH_H
 
-#include "llvm/ADT/SmallString.h"
 #include "llvm/ADT/Twine.h"
 #include "llvm/Support/DataTypes.h"
 #include <iterator>

llvm/include/llvm/Support/Process.h

@@ -25,7 +25,6 @@
 #ifndef LLVM_SUPPORT_PROCESS_H
 #define LLVM_SUPPORT_PROCESS_H
 
-#include "llvm/ADT/ArrayRef.h"
 #include "llvm/ADT/Optional.h"
 #include "llvm/Config/llvm-config.h"
 #include "llvm/Support/Allocator.h"
@@ -34,6 +33,7 @@
 #include <system_error>
 
 namespace llvm {
+template <typename T> class ArrayRef;
 class StringRef;
 
 namespace sys {

llvm/include/llvm/Support/RandomNumberGenerator.h

@@ -16,12 +16,12 @@
 #ifndef LLVM_SUPPORT_RANDOMNUMBERGENERATOR_H_
 #define LLVM_SUPPORT_RANDOMNUMBERGENERATOR_H_
 
-#include "llvm/ADT/StringRef.h"
 #include "llvm/Support/Compiler.h"
 #include "llvm/Support/DataTypes.h" // Needed for uint64_t on Windows.
 #include <random>
 
 namespace llvm {
+class StringRef;
 
 /// A random number generator.
 ///

llvm/include/llvm/Support/SHA1.h

@@ -16,12 +16,11 @@
 #ifndef LLVM_SUPPORT_SHA1_H
 #define LLVM_SUPPORT_SHA1_H
 
-#include "llvm/ADT/ArrayRef.h"
-#include "llvm/ADT/StringRef.h"
-
 #include <cstdint>
 
 namespace llvm {
+template <typename T> class ArrayRef;
+class StringRef;
 
 /// A class that wrap the SHA1 algorithm.
 class SHA1 {

llvm/include/llvm/Support/SwapByteOrder.h

@@ -18,7 +18,6 @@
 #include "llvm/Support/Compiler.h"
 #include "llvm/Support/DataTypes.h"
 #include <cstddef>
-#include <limits>
 
 namespace llvm {
 namespace sys {

llvm/include/llvm/Support/Unicode.h

@@ -15,9 +15,9 @@
 #ifndef LLVM_SUPPORT_UNICODE_H
 #define LLVM_SUPPORT_UNICODE_H
 
-#include "llvm/ADT/StringRef.h"
-
 namespace llvm {
+class StringRef;
+
 namespace sys {
 namespace unicode {
 

llvm/include/llvm/Support/YAMLParser.h

@@ -41,7 +41,6 @@
 #include "llvm/ADT/StringRef.h"
 #include "llvm/Support/Allocator.h"
 #include "llvm/Support/SMLoc.h"
-#include <limits>
 #include <map>
 #include <utility>
 

llvm/include/llvm/Support/YAMLTraits.h

@@ -10,8 +10,6 @@
 #ifndef LLVM_SUPPORT_YAMLTRAITS_H
 #define LLVM_SUPPORT_YAMLTRAITS_H
 
-#include "llvm/ADT/DenseMap.h"
-#include "llvm/ADT/DenseMapInfo.h"
 #include "llvm/ADT/Optional.h"
 #include "llvm/ADT/SmallVector.h"
 #include "llvm/ADT/StringMap.h"

llvm/include/llvm/Support/raw_sha1_ostream.h

@@ -16,6 +16,7 @@
 
 #include "llvm/Support/raw_ostream.h"
 #include "llvm/Support/SHA1.h"
+#include "llvm/ADT/ArrayRef.h"
 
 namespace llvm {
 

llvm/include/llvm/Target/TargetCallingConv.h

@@ -17,7 +17,6 @@
 #include "llvm/CodeGen/ValueTypes.h"
 #include "llvm/Support/DataTypes.h"
 #include "llvm/Support/MathExtras.h"
-#include <string>
 #include <climits>
 
 namespace llvm {

llvm/include/llvm/Target/TargetOptions.h

@@ -17,7 +17,6 @@
 
 #include "llvm/Target/TargetRecip.h"
 #include "llvm/MC/MCTargetOptions.h"
-#include <string>
 
 namespace llvm {
   class MachineFunction;

llvm/include/llvm/Target/TargetRegisterInfo.h

@@ -21,7 +21,6 @@
 #include "llvm/CodeGen/MachineValueType.h"
 #include "llvm/IR/CallingConv.h"
 #include "llvm/MC/MCRegisterInfo.h"
-#include "llvm/Support/CommandLine.h"
 #include "llvm/Support/Printable.h"
 #include <cassert>
 #include <functional>

llvm/include/llvm/Transforms/IPO.h

@@ -15,14 +15,12 @@
 #ifndef LLVM_TRANSFORMS_IPO_H
 #define LLVM_TRANSFORMS_IPO_H
 
-#include "llvm/ADT/ArrayRef.h"
-#include "llvm/ADT/StringRef.h"
-#include "llvm/ADT/StringSet.h"
-
 #include <functional>
+#include <vector>
 
 namespace llvm {
 
+class StringRef;
 class ModuleSummaryIndex;
 class ModulePass;
 class Pass;

llvm/include/llvm/Transforms/IPO/WholeProgramDevirt.h

@@ -15,7 +15,6 @@
 #ifndef LLVM_TRANSFORMS_IPO_WHOLEPROGRAMDEVIRT_H
 #define LLVM_TRANSFORMS_IPO_WHOLEPROGRAMDEVIRT_H
 
-#include "llvm/ADT/ArrayRef.h"
 #include <cassert>
 #include <cstdint>
 #include <utility>
@@ -23,6 +22,8 @@
 
 namespace llvm {
 
+template <typename T> class ArrayRef;
+template <typename T> class MutableArrayRef;
 class Function;
 class GlobalVariable;
 

llvm/include/llvm/Transforms/Scalar.h

@@ -15,7 +15,6 @@
 #ifndef LLVM_TRANSFORMS_SCALAR_H
 #define LLVM_TRANSFORMS_SCALAR_H
 
-#include "llvm/ADT/StringRef.h"
 #include <functional>
 
 namespace llvm {

llvm/include/llvm/Transforms/Utils/CodeExtractor.h

@@ -15,10 +15,10 @@
 #ifndef LLVM_TRANSFORMS_UTILS_CODEEXTRACTOR_H
 #define LLVM_TRANSFORMS_UTILS_CODEEXTRACTOR_H
 
-#include "llvm/ADT/ArrayRef.h"
 #include "llvm/ADT/SetVector.h"
 
 namespace llvm {
+template <typename T> class ArrayRef;
   class BasicBlock;
   class DominatorTree;
   class Function;

llvm/include/llvm/Transforms/Utils/ModuleUtils.h

@@ -14,12 +14,12 @@
 #ifndef LLVM_TRANSFORMS_UTILS_MODULEUTILS_H
 #define LLVM_TRANSFORMS_UTILS_MODULEUTILS_H
 
-#include "llvm/ADT/ArrayRef.h"
 #include "llvm/ADT/StringRef.h"
 #include <utility> // for std::pair
 
 namespace llvm {
 
+template <typename T> class ArrayRef;
 class Module;
 class Function;
 class GlobalValue;

llvm/include/llvm/Transforms/Utils/PromoteMemToReg.h

@@ -15,10 +15,9 @@
 #ifndef LLVM_TRANSFORMS_UTILS_PROMOTEMEMTOREG_H
 #define LLVM_TRANSFORMS_UTILS_PROMOTEMEMTOREG_H
 
-#include "llvm/ADT/ArrayRef.h"
-
 namespace llvm {
 
+template <typename T> class ArrayRef;
 class AllocaInst;
 class DominatorTree;
 class AliasSetTracker;

llvm/include/llvm/Transforms/Utils/SSAUpdater.h

@@ -14,7 +14,6 @@
 #ifndef LLVM_TRANSFORMS_UTILS_SSAUPDATER_H
 #define LLVM_TRANSFORMS_UTILS_SSAUPDATER_H
 
-#include "llvm/ADT/ArrayRef.h"
 #include "llvm/ADT/StringRef.h"
 #include "llvm/Support/Compiler.h"
 
@@ -22,8 +21,9 @@ namespace llvm {
   class BasicBlock;
   class Instruction;
   class LoadInst;
-  template<typename T> class SmallVectorImpl;
-  template<typename T> class SSAUpdaterTraits;
+  template <typename T> class ArrayRef;
+  template <typename T> class SmallVectorImpl;
+  template <typename T> class SSAUpdaterTraits;
   class PHINode;
   class Type;
   class Use;

llvm/include/llvm/Transforms/Utils/SimplifyIndVar.h

@@ -17,7 +17,6 @@
 #define LLVM_TRANSFORMS_UTILS_SIMPLIFYINDVAR_H
 
 #include "llvm/IR/ValueHandle.h"
-#include "llvm/Support/CommandLine.h"
 
 namespace llvm {
 

llvm/include/llvm/Transforms/Utils/SimplifyLibCalls.h

@@ -16,11 +16,11 @@
 #define LLVM_TRANSFORMS_UTILS_SIMPLIFYLIBCALLS_H
 
 #include "llvm/ADT/STLExtras.h"
-#include "llvm/ADT/StringRef.h"
 #include "llvm/Analysis/TargetLibraryInfo.h"
 #include "llvm/IR/IRBuilder.h"
 
 namespace llvm {
+class StringRef;
 class Value;
 class CallInst;
 class DataLayout;

llvm/include/llvm/Transforms/Utils/UnrollLoop.h

@@ -16,10 +16,10 @@
 #ifndef LLVM_TRANSFORMS_UTILS_UNROLLLOOP_H
 #define LLVM_TRANSFORMS_UTILS_UNROLLLOOP_H
 
-#include "llvm/ADT/StringRef.h"
 
 namespace llvm {
 
+class StringRef;
 class AssumptionCache;
 class DominatorTree;
 class Loop;