diff --git a/llvm/lib/Analysis/Lint.cpp b/llvm/lib/Analysis/Lint.cpp
index cf055b182786..f9a7a5bdf434 100644
--- a/llvm/lib/Analysis/Lint.cpp
+++ b/llvm/lib/Analysis/Lint.cpp
@@ -715,6 +715,7 @@ PreservedAnalyses LintPass::run(Function &F, FunctionAnalysisManager &AM) {
   return PreservedAnalyses::all();
 }
 
+namespace {
 class LintLegacyPass : public FunctionPass {
 public:
   static char ID; // Pass identification, replacement for typeid
@@ -733,6 +734,7 @@ public:
   }
   void print(raw_ostream &O, const Module *M) const override {}
 };
+} // namespace
 
 char LintLegacyPass::ID = 0;
 INITIALIZE_PASS_BEGIN(LintLegacyPass, "lint", "Statically lint-checks LLVM IR",
diff --git a/llvm/lib/CodeGen/LiveDebugValues/LiveDebugValues.cpp b/llvm/lib/CodeGen/LiveDebugValues/LiveDebugValues.cpp
index fe9eb6dd6e9e..691977dc34e6 100644
--- a/llvm/lib/CodeGen/LiveDebugValues/LiveDebugValues.cpp
+++ b/llvm/lib/CodeGen/LiveDebugValues/LiveDebugValues.cpp
@@ -52,6 +52,7 @@ static cl::opt<unsigned> InputDbgValueLimit(
         "Maximum input DBG_VALUE insts supported by debug range extension"),
     cl::init(50000), cl::Hidden);
 
+namespace {
 /// Generic LiveDebugValues pass. Calls through to VarLocBasedLDV or
 /// InstrRefBasedLDV to perform location propagation, via the LDVImpl
 /// base class.
@@ -81,6 +82,7 @@ private:
   TargetPassConfig *TPC;
   MachineDominatorTree MDT;
 };
+} // namespace
 
 char LiveDebugValues::ID = 0;
 
diff --git a/llvm/lib/Support/VirtualFileSystem.cpp b/llvm/lib/Support/VirtualFileSystem.cpp
index 433b07183246..c1adf57d1c9f 100644
--- a/llvm/lib/Support/VirtualFileSystem.cpp
+++ b/llvm/lib/Support/VirtualFileSystem.cpp
@@ -1117,6 +1117,7 @@ public:
   }
 };
 
+namespace {
 /// Directory iterator implementation for \c RedirectingFileSystem's
 /// directory remap entries that maps the paths reported by the external
 /// file system's directory iterator back to the virtual directory's path.
@@ -1155,6 +1156,7 @@ public:
     return EC;
   }
 };
+} // namespace
 
 llvm::ErrorOr<std::string>
 RedirectingFileSystem::getCurrentWorkingDirectory() const {
diff --git a/llvm/lib/Target/AMDGPU/AMDGPUAttributor.cpp b/llvm/lib/Target/AMDGPU/AMDGPUAttributor.cpp
index c3b2f9462ce7..f0aadab3302f 100644
--- a/llvm/lib/Target/AMDGPU/AMDGPUAttributor.cpp
+++ b/llvm/lib/Target/AMDGPU/AMDGPUAttributor.cpp
@@ -112,6 +112,7 @@ static bool isDSAddress(const Constant *C) {
   return AS == AMDGPUAS::LOCAL_ADDRESS || AS == AMDGPUAS::REGION_ADDRESS;
 }
 
+namespace {
 class AMDGPUInformationCache : public InformationCache {
 public:
   AMDGPUInformationCache(const Module &M, AnalysisGetter &AG,
@@ -643,6 +644,7 @@ public:
   TargetMachine *TM;
   static char ID;
 };
+} // namespace
 
 char AMDGPUAttributor::ID = 0;
 
diff --git a/llvm/lib/Target/Mips/MipsCallLowering.cpp b/llvm/lib/Target/Mips/MipsCallLowering.cpp
index 97062cf619a2..f6ec34c7f403 100644
--- a/llvm/lib/Target/Mips/MipsCallLowering.cpp
+++ b/llvm/lib/Target/Mips/MipsCallLowering.cpp
@@ -24,6 +24,7 @@ using namespace llvm;
 MipsCallLowering::MipsCallLowering(const MipsTargetLowering &TLI)
     : CallLowering(&TLI) {}
 
+namespace {
 struct MipsOutgoingValueAssigner : public CallLowering::OutgoingValueAssigner {
   /// This is the name of the function being called
   /// FIXME: Relying on this is unsound
@@ -80,7 +81,6 @@ struct MipsIncomingValueAssigner : public CallLowering::IncomingValueAssigner {
   }
 };
 
-namespace {
 class MipsIncomingValueHandler : public CallLowering::IncomingValueHandler {
   const MipsSubtarget &STI;
 
diff --git a/llvm/lib/Target/X86/X86LowerAMXIntrinsics.cpp b/llvm/lib/Target/X86/X86LowerAMXIntrinsics.cpp
index 08cf86b45440..243ae213d665 100644
--- a/llvm/lib/Target/X86/X86LowerAMXIntrinsics.cpp
+++ b/llvm/lib/Target/X86/X86LowerAMXIntrinsics.cpp
@@ -630,6 +630,7 @@ bool X86LowerAMXIntrinsics::visit() {
   return C;
 }
 
+namespace {
 class X86LowerAMXIntrinsicsLegacyPass : public FunctionPass {
 public:
   static char ID;
@@ -664,6 +665,7 @@ public:
     AU.addRequired<TargetPassConfig>();
   }
 };
+} // namespace
 
 static const char PassName[] = "Lower AMX intrinsics";
 char X86LowerAMXIntrinsicsLegacyPass::ID = 0;
diff --git a/llvm/lib/Transforms/IPO/AttributorAttributes.cpp b/llvm/lib/Transforms/IPO/AttributorAttributes.cpp
index badb118ec2a4..cd1d0f3163fd 100644
--- a/llvm/lib/Transforms/IPO/AttributorAttributes.cpp
+++ b/llvm/lib/Transforms/IPO/AttributorAttributes.cpp
@@ -483,6 +483,7 @@ static void clampReturnedValueStates(
     S ^= *T;
 }
 
+namespace {
 /// Helper class for generic deduction: return value -> returned position.
 template <typename AAType, typename BaseType,
           typename StateType = typename BaseType::StateType,
@@ -641,6 +642,7 @@ struct AACallSiteReturnedFromReturned : public BaseType {
     return clampStateAndIndicateChange(S, AA.getState());
   }
 };
+} // namespace
 
 /// Helper function to accumulate uses.
 template <class AAType, typename StateType = typename AAType::StateType>
@@ -1031,6 +1033,7 @@ private:
   BooleanState BS;
 };
 
+namespace {
 struct AAPointerInfoImpl
     : public StateWrapper<AA::PointerInfo::State, AAPointerInfo> {
   using BaseTy = StateWrapper<AA::PointerInfo::State, AAPointerInfo>;
@@ -5074,6 +5077,7 @@ struct AANoCaptureCallSiteReturned final : AANoCaptureImpl {
     STATS_DECLTRACK_CSRET_ATTR(nocapture)
   }
 };
+} // namespace
 
 /// ------------------ Value Simplify Attribute ----------------------------
 
@@ -5094,6 +5098,7 @@ bool ValueSimplifyStateType::unionAssumed(Optional<Value *> Other) {
   return true;
 }
 
+namespace {
 struct AAValueSimplifyImpl : AAValueSimplify {
   AAValueSimplifyImpl(const IRPosition &IRP, Attributor &A)
       : AAValueSimplify(IRP, A) {}
@@ -7373,6 +7378,7 @@ void AAMemoryBehaviorFloating::analyzeUseIn(Attributor &A, const Use &U,
   if (UserI->mayWriteToMemory())
     removeAssumedBits(NO_WRITES);
 }
+} // namespace
 
 /// -------------------- Memory Locations Attributes ---------------------------
 /// Includes read-none, argmemonly, inaccessiblememonly,
diff --git a/llvm/lib/Transforms/IPO/FunctionSpecialization.cpp b/llvm/lib/Transforms/IPO/FunctionSpecialization.cpp
index fdb240d58125..fbd083bb9bbf 100644
--- a/llvm/lib/Transforms/IPO/FunctionSpecialization.cpp
+++ b/llvm/lib/Transforms/IPO/FunctionSpecialization.cpp
@@ -229,6 +229,7 @@ static void removeSSACopy(Module &M) {
     removeSSACopy(F);
 }
 
+namespace {
 class FunctionSpecializer {
 
   /// The IPSCCP Solver.
@@ -737,6 +738,7 @@ private:
     }
   }
 };
+} // namespace
 
 bool llvm::runFunctionSpecialization(
     Module &M, const DataLayout &DL,
diff --git a/llvm/lib/Transforms/IPO/IROutliner.cpp b/llvm/lib/Transforms/IPO/IROutliner.cpp
index bd3012c576dd..b8a314c54f18 100644
--- a/llvm/lib/Transforms/IPO/IROutliner.cpp
+++ b/llvm/lib/Transforms/IPO/IROutliner.cpp
@@ -2206,6 +2206,7 @@ bool IROutliner::run(Module &M) {
 }
 
 // Pass Manager Boilerplate
+namespace {
 class IROutlinerLegacyPass : public ModulePass {
 public:
   static char ID;
@@ -2221,6 +2222,7 @@ public:
 
   bool runOnModule(Module &M) override;
 };
+} // namespace
 
 bool IROutlinerLegacyPass::runOnModule(Module &M) {
   if (skipModule(M))
diff --git a/llvm/lib/Transforms/IPO/SCCP.cpp b/llvm/lib/Transforms/IPO/SCCP.cpp
index 081398a390fa..5779553ee732 100644
--- a/llvm/lib/Transforms/IPO/SCCP.cpp
+++ b/llvm/lib/Transforms/IPO/SCCP.cpp
@@ -135,6 +135,7 @@ PreservedAnalyses FunctionSpecializationPass::run(Module &M,
   return PA;
 }
 
+namespace {
 struct FunctionSpecializationLegacyPass : public ModulePass {
   static char ID; // Pass identification, replacement for typeid
   FunctionSpecializationLegacyPass() : ModulePass(ID) {}
@@ -175,6 +176,7 @@ struct FunctionSpecializationLegacyPass : public ModulePass {
     return runFunctionSpecialization(M, DL, GetTLI, GetTTI, GetAC, GetAnalysis);
   }
 };
+} // namespace
 
 char FunctionSpecializationLegacyPass::ID = 0;
 
diff --git a/llvm/lib/Transforms/Scalar/LoopInterchange.cpp b/llvm/lib/Transforms/Scalar/LoopInterchange.cpp
index 1d09bb1d5ced..9f605b4ac4ad 100644
--- a/llvm/lib/Transforms/Scalar/LoopInterchange.cpp
+++ b/llvm/lib/Transforms/Scalar/LoopInterchange.cpp
@@ -1763,6 +1763,7 @@ bool LoopInterchangeTransform::adjustLoopLinks() {
   return Changed;
 }
 
+namespace {
 /// Main LoopInterchange Pass.
 struct LoopInterchangeLegacyPass : public LoopPass {
   static char ID;
@@ -1791,6 +1792,7 @@ struct LoopInterchangeLegacyPass : public LoopPass {
     return LoopInterchange(SE, LI, DI, DT, ORE).run(L);
   }
 };
+} // namespace
 
 char LoopInterchangeLegacyPass::ID = 0;
 
diff --git a/llvm/lib/Transforms/Scalar/LoopStrengthReduce.cpp b/llvm/lib/Transforms/Scalar/LoopStrengthReduce.cpp
index 10b47c3585a9..4ffcdba1ae1e 100644
--- a/llvm/lib/Transforms/Scalar/LoopStrengthReduce.cpp
+++ b/llvm/lib/Transforms/Scalar/LoopStrengthReduce.cpp
@@ -5868,6 +5868,7 @@ void LoopStrengthReduce::getAnalysisUsage(AnalysisUsage &AU) const {
   AU.addPreserved<MemorySSAWrapperPass>();
 }
 
+namespace {
 struct SCEVDbgValueBuilder {
   SCEVDbgValueBuilder() = default;
   SCEVDbgValueBuilder(const SCEVDbgValueBuilder &Base) {
@@ -6115,6 +6116,7 @@ struct DVIRecoveryRec {
   Metadata *LocationOp;
   const llvm::SCEV *SCEV;
 };
+} // namespace
 
 static void RewriteDVIUsingIterCount(DVIRecoveryRec CachedDVI,
                                      const SCEVDbgValueBuilder &IterationCount,
diff --git a/llvm/lib/Transforms/Utils/InlineFunction.cpp b/llvm/lib/Transforms/Utils/InlineFunction.cpp
index 7cbfcc3703b6..01594a8ac90e 100644
--- a/llvm/lib/Transforms/Utils/InlineFunction.cpp
+++ b/llvm/lib/Transforms/Utils/InlineFunction.cpp
@@ -828,6 +828,7 @@ static void PropagateCallSiteMetadata(CallBase &CB, Function::iterator FStart,
   }
 }
 
+namespace {
 /// Utility for cloning !noalias and !alias.scope metadata. When a code region
 /// using scoped alias metadata is inlined, the aliasing relationships may not
 /// hold between the two version. It is necessary to create a deep clone of the
@@ -849,6 +850,7 @@ public:
   /// metadata.
   void remap(Function::iterator FStart, Function::iterator FEnd);
 };
+} // namespace
 
 ScopedAliasMetadataDeepCloner::ScopedAliasMetadataDeepCloner(
     const Function *F) {
diff --git a/llvm/lib/Transforms/Utils/SimplifyIndVar.cpp b/llvm/lib/Transforms/Utils/SimplifyIndVar.cpp
index bd30be011472..5b7fd4349c6c 100644
--- a/llvm/lib/Transforms/Utils/SimplifyIndVar.cpp
+++ b/llvm/lib/Transforms/Utils/SimplifyIndVar.cpp
@@ -942,6 +942,7 @@ bool simplifyLoopIVs(Loop *L, ScalarEvolution *SE, DominatorTree *DT,
 
 } // namespace llvm
 
+namespace {
 //===----------------------------------------------------------------------===//
 // Widen Induction Variables - Extend the width of an IV to cover its
 // widest uses.
@@ -1072,7 +1073,7 @@ protected:
 private:
   SmallVector<NarrowIVDefUse, 8> NarrowIVUsers;
 };
-
+} // namespace
 
 /// Determine the insertion point for this user. By default, insert immediately
 /// before the user. SCEVExpander or LICM will hoist loop invariants out of the