diff --git a/llvm/include/llvm/CodeGen/MachineInstr.h b/llvm/include/llvm/CodeGen/MachineInstr.h
index 102b1eb07358e..a5d41733085de 100644
--- a/llvm/include/llvm/CodeGen/MachineInstr.h
+++ b/llvm/include/llvm/CodeGen/MachineInstr.h
@@ -612,26 +612,12 @@ class MachineInstr
 
   /// Returns a range of all of the operands that correspond to a debug use of
   /// \p Reg.
-  template <typename Operand, typename Instruction>
-  static iterator_range<
-      filter_iterator<Operand *, std::function<bool(Operand &Op)>>>
-  getDebugOperandsForReg(Instruction *MI, Register Reg) {
-    std::function<bool(Operand & Op)> OpUsesReg(
-        [Reg](Operand &Op) { return Op.isReg() && Op.getReg() == Reg; });
-    return make_filter_range(MI->debug_operands(), OpUsesReg);
-  }
   iterator_range<filter_iterator<const MachineOperand *,
                                  std::function<bool(const MachineOperand &Op)>>>
-  getDebugOperandsForReg(Register Reg) const {
-    return MachineInstr::getDebugOperandsForReg<const MachineOperand,
-                                                const MachineInstr>(this, Reg);
-  }
+  getDebugOperandsForReg(Register Reg) const;
   iterator_range<filter_iterator<MachineOperand *,
                                  std::function<bool(MachineOperand &Op)>>>
-  getDebugOperandsForReg(Register Reg) {
-    return MachineInstr::getDebugOperandsForReg<MachineOperand, MachineInstr>(
-        this, Reg);
-  }
+  getDebugOperandsForReg(Register Reg);
 
   bool isDebugOperand(const MachineOperand *Op) const {
     return Op >= adl_begin(debug_operands()) && Op <= adl_end(debug_operands());
diff --git a/llvm/include/llvm/CodeGen/TargetLowering.h b/llvm/include/llvm/CodeGen/TargetLowering.h
index 4f2f202f94841..0a36975f4f625 100644
--- a/llvm/include/llvm/CodeGen/TargetLowering.h
+++ b/llvm/include/llvm/CodeGen/TargetLowering.h
@@ -329,9 +329,6 @@ class TargetLoweringBase {
   };
   using ArgListTy = std::vector<ArgListEntry>;
 
-  virtual void markLibCallAttributes(MachineFunction *MF, unsigned CC,
-                                     ArgListTy &Args) const {};
-
   static ISD::NodeType getExtendForContent(BooleanContent Content) {
     switch (Content) {
     case UndefinedBooleanContent:
@@ -350,7 +347,7 @@ class TargetLoweringBase {
   explicit TargetLoweringBase(const TargetMachine &TM);
   TargetLoweringBase(const TargetLoweringBase &) = delete;
   TargetLoweringBase &operator=(const TargetLoweringBase &) = delete;
-  virtual ~TargetLoweringBase() = default;
+  virtual ~TargetLoweringBase();
 
   /// Return true if the target support strict float operation
   bool isStrictFPEnabled() const {
@@ -3866,6 +3863,7 @@ class TargetLowering : public TargetLoweringBase {
   TargetLowering &operator=(const TargetLowering &) = delete;
 
   explicit TargetLowering(const TargetMachine &TM);
+  ~TargetLowering() override;
 
   bool isPositionIndependent() const;
 
@@ -4592,6 +4590,9 @@ class TargetLowering : public TargetLoweringBase {
     llvm_unreachable("Not Implemented");
   }
 
+  virtual void markLibCallAttributes(MachineFunction *MF, unsigned CC,
+                                     ArgListTy &Args) const {}
+
   /// This structure contains the information necessary for lowering
   /// pointer-authenticating indirect calls.  It is equivalent to the "ptrauth"
   /// operand bundle found on the call instruction, if any.
diff --git a/llvm/include/llvm/Target/TargetMachine.h b/llvm/include/llvm/Target/TargetMachine.h
index 27eeb415ed644..5a16c9cafcd7a 100644
--- a/llvm/include/llvm/Target/TargetMachine.h
+++ b/llvm/include/llvm/Target/TargetMachine.h
@@ -16,7 +16,6 @@
 #include "llvm/ADT/StringRef.h"
 #include "llvm/IR/DataLayout.h"
 #include "llvm/IR/PassManager.h"
-#include "llvm/MC/MCStreamer.h"
 #include "llvm/Support/Allocator.h"
 #include "llvm/Support/CodeGen.h"
 #include "llvm/Support/CommandLine.h"
@@ -45,6 +44,7 @@ class MCAsmInfo;
 class MCContext;
 class MCInstrInfo;
 class MCRegisterInfo;
+class MCStreamer;
 class MCSubtargetInfo;
 class MCSymbol;
 class raw_pwrite_stream;
@@ -490,9 +490,7 @@ class TargetMachine {
 
   virtual Expected<std::unique_ptr<MCStreamer>>
   createMCStreamer(raw_pwrite_stream &Out, raw_pwrite_stream *DwoOut,
-                   CodeGenFileType FileType, MCContext &Ctx) {
-    return nullptr;
-  }
+                   CodeGenFileType FileType, MCContext &Ctx);
 
   /// True if the target uses physical regs (as nearly all targets do). False
   /// for stack machines such as WebAssembly and other virtual-register
diff --git a/llvm/lib/CodeGen/MachineInstr.cpp b/llvm/lib/CodeGen/MachineInstr.cpp
index 2409e601ceb46..7e4a32f67fe6a 100644
--- a/llvm/lib/CodeGen/MachineInstr.cpp
+++ b/llvm/lib/CodeGen/MachineInstr.cpp
@@ -794,6 +794,28 @@ bool MachineInstr::shouldUpdateAdditionalCallInfo() const {
   return isCandidateForAdditionalCallInfo();
 }
 
+template <typename Operand, typename Instruction>
+static iterator_range<
+    filter_iterator<Operand *, std::function<bool(Operand &Op)>>>
+getDebugOperandsForRegHelper(Instruction *MI, Register Reg) {
+  std::function<bool(Operand & Op)> OpUsesReg(
+      [Reg](Operand &Op) { return Op.isReg() && Op.getReg() == Reg; });
+  return make_filter_range(MI->debug_operands(), OpUsesReg);
+}
+
+iterator_range<filter_iterator<const MachineOperand *,
+                               std::function<bool(const MachineOperand &Op)>>>
+MachineInstr::getDebugOperandsForReg(Register Reg) const {
+  return getDebugOperandsForRegHelper<const MachineOperand, const MachineInstr>(
+      this, Reg);
+}
+
+iterator_range<
+    filter_iterator<MachineOperand *, std::function<bool(MachineOperand &Op)>>>
+MachineInstr::getDebugOperandsForReg(Register Reg) {
+  return getDebugOperandsForRegHelper<MachineOperand, MachineInstr>(this, Reg);
+}
+
 unsigned MachineInstr::getNumExplicitOperands() const {
   unsigned NumOperands = MCID->getNumOperands();
   if (!MCID->isVariadic())
diff --git a/llvm/lib/CodeGen/SelectionDAG/TargetLowering.cpp b/llvm/lib/CodeGen/SelectionDAG/TargetLowering.cpp
index 89f806d8b1c30..5308593b5c988 100644
--- a/llvm/lib/CodeGen/SelectionDAG/TargetLowering.cpp
+++ b/llvm/lib/CodeGen/SelectionDAG/TargetLowering.cpp
@@ -41,6 +41,9 @@ using namespace llvm;
 TargetLowering::TargetLowering(const TargetMachine &tm)
     : TargetLoweringBase(tm) {}
 
+// Define the virtual destructor out-of-line for build efficiency.
+TargetLowering::~TargetLowering() = default;
+
 const char *TargetLowering::getTargetNodeName(unsigned Opcode) const {
   return nullptr;
 }
diff --git a/llvm/lib/CodeGen/TargetLoweringBase.cpp b/llvm/lib/CodeGen/TargetLoweringBase.cpp
index 91ae9040581ee..483e52d16d537 100644
--- a/llvm/lib/CodeGen/TargetLoweringBase.cpp
+++ b/llvm/lib/CodeGen/TargetLoweringBase.cpp
@@ -668,6 +668,10 @@ TargetLoweringBase::TargetLoweringBase(const TargetMachine &tm)
   RTLIB::initCmpLibcallCCs(CmpLibcallCCs);
 }
 
+// Define the virtual destructor out-of-line to act as a key method to anchor
+// debug info (see coding standards).
+TargetLoweringBase::~TargetLoweringBase() = default;
+
 void TargetLoweringBase::initActions() {
   // All operations default to being supported.
   memset(OpActions, 0, sizeof(OpActions));
diff --git a/llvm/lib/Target/TargetMachine.cpp b/llvm/lib/Target/TargetMachine.cpp
index 027ae62007a72..439e735e9d66e 100644
--- a/llvm/lib/Target/TargetMachine.cpp
+++ b/llvm/lib/Target/TargetMachine.cpp
@@ -21,6 +21,7 @@
 #include "llvm/MC/MCContext.h"
 #include "llvm/MC/MCInstrInfo.h"
 #include "llvm/MC/MCRegisterInfo.h"
+#include "llvm/MC/MCStreamer.h"
 #include "llvm/MC/MCSubtargetInfo.h"
 #include "llvm/Support/CodeGen.h"
 #include "llvm/Target/TargetLoweringObjectFile.h"
@@ -45,6 +46,13 @@ TargetMachine::TargetMachine(const Target &T, StringRef DataLayoutString,
 
 TargetMachine::~TargetMachine() = default;
 
+Expected<std::unique_ptr<MCStreamer>>
+TargetMachine::createMCStreamer(raw_pwrite_stream &Out,
+                                raw_pwrite_stream *DwoOut,
+                                CodeGenFileType FileType, MCContext &Ctx) {
+  return nullptr;
+}
+
 bool TargetMachine::isLargeGlobalValue(const GlobalValue *GVal) const {
   if (getTargetTriple().getArch() != Triple::x86_64)
     return false;
diff --git a/llvm/lib/Target/X86/X86Subtarget.cpp b/llvm/lib/Target/X86/X86Subtarget.cpp
index b563f6ebce34e..81bfe4b28be8e 100644
--- a/llvm/lib/Target/X86/X86Subtarget.cpp
+++ b/llvm/lib/Target/X86/X86Subtarget.cpp
@@ -361,6 +361,9 @@ X86Subtarget::X86Subtarget(const Triple &TT, StringRef CPU, StringRef TuneCPU,
   InstSelector.reset(createX86InstructionSelector(TM, *this, *RBI));
 }
 
+// Define the virtual destructor out-of-line for build efficiency.
+X86Subtarget::~X86Subtarget() = default;
+
 const CallLowering *X86Subtarget::getCallLowering() const {
   return CallLoweringInfo.get();
 }
diff --git a/llvm/lib/Target/X86/X86Subtarget.h b/llvm/lib/Target/X86/X86Subtarget.h
index 8f2d326a69398..b53350efc85f5 100644
--- a/llvm/lib/Target/X86/X86Subtarget.h
+++ b/llvm/lib/Target/X86/X86Subtarget.h
@@ -17,7 +17,6 @@
 #include "X86ISelLowering.h"
 #include "X86InstrInfo.h"
 #include "X86SelectionDAGInfo.h"
-#include "llvm/CodeGen/GlobalISel/LegalizerInfo.h"
 #include "llvm/CodeGen/TargetSubtargetInfo.h"
 #include "llvm/IR/CallingConv.h"
 #include "llvm/TargetParser/Triple.h"
@@ -114,6 +113,7 @@ class X86Subtarget final : public X86GenSubtargetInfo {
                const X86TargetMachine &TM, MaybeAlign StackAlignOverride,
                unsigned PreferVectorWidthOverride,
                unsigned RequiredVectorWidth);
+  ~X86Subtarget() override;
 
   const X86TargetLowering *getTargetLowering() const override {
     return &TLInfo;
diff --git a/llvm/lib/Target/X86/X86TargetTransformInfo.cpp b/llvm/lib/Target/X86/X86TargetTransformInfo.cpp
index 7d168d33bb3e9..41e437a47ba29 100644
--- a/llvm/lib/Target/X86/X86TargetTransformInfo.cpp
+++ b/llvm/lib/Target/X86/X86TargetTransformInfo.cpp
@@ -49,6 +49,7 @@
 //===----------------------------------------------------------------------===//
 
 #include "X86TargetTransformInfo.h"
+#include "llvm/ADT/SmallBitVector.h"
 #include "llvm/Analysis/TargetTransformInfo.h"
 #include "llvm/CodeGen/BasicTTIImpl.h"
 #include "llvm/CodeGen/CostTable.h"