TargetLowering.h - remove unnecessary TargetMachine.h include. NFC

Replace with forward declaration and move dependency down to source files that actually need it.

Both TargetLowering.h and TargetMachine.h are 2 of the most expensive headers (top 10) in the ClangBuildAnalyzer report when building llc.

llvm/include/llvm/CodeGen/TargetLowering.h

@@ -50,7 +50,6 @@
 #include "llvm/Support/Casting.h"
 #include "llvm/Support/ErrorHandling.h"
 #include "llvm/Support/MachineValueType.h"
-#include "llvm/Target/TargetMachine.h"
 #include <algorithm>
 #include <cassert>
 #include <climits>
@@ -86,6 +85,7 @@ class MCExpr;
 class Module;
 class ProfileSummaryInfo;
 class TargetLibraryInfo;
+class TargetMachine;
 class TargetRegisterClass;
 class TargetRegisterInfo;
 class TargetTransformInfo;

llvm/lib/CodeGen/Analysis.cpp

@@ -25,6 +25,7 @@
 #include "llvm/IR/Module.h"
 #include "llvm/Support/ErrorHandling.h"
 #include "llvm/Support/MathExtras.h"
+#include "llvm/Target/TargetMachine.h"
 #include "llvm/Transforms/Utils/GlobalStatus.h"
 
 using namespace llvm;

llvm/lib/CodeGen/AsmPrinter/WinException.cpp

@@ -34,6 +34,7 @@
 #include "llvm/Support/ErrorHandling.h"
 #include "llvm/Support/FormattedStream.h"
 #include "llvm/Target/TargetLoweringObjectFile.h"
+#include "llvm/Target/TargetMachine.h"
 #include "llvm/Target/TargetOptions.h"
 using namespace llvm;
 

llvm/lib/CodeGen/ExpandMemCmp.cpp

@@ -25,6 +25,7 @@
 #include "llvm/InitializePasses.h"
 #include "llvm/Transforms/Utils/Local.h"
 #include "llvm/Transforms/Utils/SizeOpts.h"
+#include "llvm/Target/TargetMachine.h"
 
 using namespace llvm;
 

llvm/lib/CodeGen/GlobalISel/CallLowering.cpp

@@ -22,6 +22,7 @@
 #include "llvm/IR/Instructions.h"
 #include "llvm/IR/LLVMContext.h"
 #include "llvm/IR/Module.h"
+#include "llvm/Target/TargetMachine.h"
 
 #define DEBUG_TYPE "call-lowering"
 

llvm/lib/CodeGen/GlobalISel/InstructionSelect.cpp

@@ -29,6 +29,7 @@
 #include "llvm/Support/CommandLine.h"
 #include "llvm/Support/Debug.h"
 #include "llvm/Support/TargetRegistry.h"
+#include "llvm/Target/TargetMachine.h"
 
 #define DEBUG_TYPE "instruction-select"
 

llvm/lib/CodeGen/LiveDebugValues.cpp

@@ -64,6 +64,7 @@
 #include "llvm/Support/Compiler.h"
 #include "llvm/Support/Debug.h"
 #include "llvm/Support/raw_ostream.h"
+#include "llvm/Target/TargetMachine.h"
 #include <algorithm>
 #include <cassert>
 #include <cstdint>

llvm/lib/CodeGen/LowerEmuTLS.cpp

@@ -21,6 +21,7 @@
 #include "llvm/IR/Module.h"
 #include "llvm/InitializePasses.h"
 #include "llvm/Pass.h"
+#include "llvm/Target/TargetMachine.h"
 
 using namespace llvm;
 

llvm/lib/CodeGen/SelectionDAG/InstrEmitter.cpp

@@ -29,6 +29,7 @@
 #include "llvm/Support/Debug.h"
 #include "llvm/Support/ErrorHandling.h"
 #include "llvm/Support/MathExtras.h"
+#include "llvm/Target/TargetMachine.h"
 using namespace llvm;
 
 #define DEBUG_TYPE "instr-emitter"

llvm/lib/CodeGen/SelectionDAG/ScheduleDAGSDNodes.cpp

@@ -31,6 +31,7 @@
 #include "llvm/Support/CommandLine.h"
 #include "llvm/Support/Debug.h"
 #include "llvm/Support/raw_ostream.h"
+#include "llvm/Target/TargetMachine.h"
 using namespace llvm;
 
 #define DEBUG_TYPE "pre-RA-sched"

llvm/lib/CodeGen/SwitchLoweringUtils.cpp

@@ -13,6 +13,7 @@
 
 #include "llvm/CodeGen/MachineJumpTableInfo.h"
 #include "llvm/CodeGen/SwitchLoweringUtils.h"
+#include "llvm/Target/TargetMachine.h"
 
 using namespace llvm;
 using namespace SwitchCG;

llvm/lib/CodeGen/TypePromotion.cpp

@@ -40,6 +40,7 @@
 #include "llvm/Pass.h"
 #include "llvm/Support/Casting.h"
 #include "llvm/Support/CommandLine.h"
+#include "llvm/Target/TargetMachine.h"
 
 #define DEBUG_TYPE "type-promotion"
 #define PASS_NAME "Type Promotion"

llvm/lib/LTO/UpdateCompilerUsed.cpp

@@ -17,6 +17,7 @@
 #include "llvm/IR/LegacyPassManager.h"
 #include "llvm/IR/Mangler.h"
 #include "llvm/Transforms/Utils/ModuleUtils.h"
+#include "llvm/Target/TargetMachine.h"
 
 using namespace llvm;
 

llvm/lib/Target/ARM/ARMSubtarget.h

@@ -28,6 +28,7 @@
 #include "llvm/CodeGen/TargetSubtargetInfo.h"
 #include "llvm/MC/MCInstrItineraries.h"
 #include "llvm/MC/MCSchedule.h"
+#include "llvm/Target/TargetMachine.h"
 #include "llvm/Target/TargetOptions.h"
 #include <memory>
 #include <string>

llvm/lib/Target/Sparc/SparcTargetObjectFile.cpp

@@ -11,6 +11,7 @@
 #include "llvm/BinaryFormat/Dwarf.h"
 #include "llvm/CodeGen/MachineModuleInfoImpls.h"
 #include "llvm/CodeGen/TargetLowering.h"
+#include "llvm/Target/TargetMachine.h"
 
 using namespace llvm;
 

llvm/lib/Target/SystemZ/SystemZFrameLowering.cpp

@@ -17,6 +17,7 @@
 #include "llvm/CodeGen/MachineRegisterInfo.h"
 #include "llvm/CodeGen/RegisterScavenging.h"
 #include "llvm/IR/Function.h"
+#include "llvm/Target/TargetMachine.h"
 
 using namespace llvm;
 

llvm/lib/Target/SystemZ/SystemZSubtarget.cpp

@@ -9,6 +9,7 @@
 #include "SystemZSubtarget.h"
 #include "MCTargetDesc/SystemZMCTargetDesc.h"
 #include "llvm/IR/GlobalValue.h"
+#include "llvm/Target/TargetMachine.h"
 
 using namespace llvm;
 

llvm/lib/Target/SystemZ/SystemZTDC.cpp

@@ -55,6 +55,7 @@
 #include "llvm/IR/IntrinsicsS390.h"
 #include "llvm/IR/LegacyPassManager.h"
 #include "llvm/IR/Module.h"
+#include "llvm/Target/TargetMachine.h"
 #include <deque>
 #include <set>
 

llvm/lib/Target/WebAssembly/WebAssemblyCFGStackify.cpp

@@ -31,6 +31,7 @@
 #include "llvm/CodeGen/MachineInstrBuilder.h"
 #include "llvm/CodeGen/MachineLoopInfo.h"
 #include "llvm/MC/MCAsmInfo.h"
+#include "llvm/Target/TargetMachine.h"
 using namespace llvm;
 
 #define DEBUG_TYPE "wasm-cfg-stackify"

llvm/lib/Target/WebAssembly/WebAssemblyLateEHPrepare.cpp

@@ -20,6 +20,7 @@
 #include "llvm/CodeGen/WasmEHFuncInfo.h"
 #include "llvm/MC/MCAsmInfo.h"
 #include "llvm/Support/Debug.h"
+#include "llvm/Target/TargetMachine.h"
 using namespace llvm;
 
 #define DEBUG_TYPE "wasm-late-eh-prepare"

llvm/lib/Target/WebAssembly/WebAssemblyMachineFunctionInfo.cpp

@@ -16,6 +16,7 @@
 #include "WebAssemblyISelLowering.h"
 #include "WebAssemblySubtarget.h"
 #include "llvm/CodeGen/Analysis.h"
+#include "llvm/Target/TargetMachine.h"
 using namespace llvm;
 
 WebAssemblyFunctionInfo::~WebAssemblyFunctionInfo() = default; // anchor.

llvm/lib/Target/X86/X86Subtarget.h

@@ -20,6 +20,7 @@
 #include "llvm/ADT/Triple.h"
 #include "llvm/CodeGen/TargetSubtargetInfo.h"
 #include "llvm/IR/CallingConv.h"
+#include "llvm/Target/TargetMachine.h"
 #include <climits>
 #include <memory>
 
@@ -34,7 +35,6 @@ class InstructionSelector;
 class LegalizerInfo;
 class RegisterBankInfo;
 class StringRef;
-class TargetMachine;
 
 /// The X86 backend supports a number of different styles of PIC.
 ///

llvm/lib/Target/X86/X86TargetObjectFile.cpp

@@ -18,6 +18,7 @@
 #include "llvm/MC/MCSectionCOFF.h"
 #include "llvm/MC/MCSectionELF.h"
 #include "llvm/MC/MCValue.h"
+#include "llvm/Target/TargetMachine.h"
 
 using namespace llvm;
 using namespace dwarf;