diff --git a/lib/AsmParser/LLParser.cpp b/lib/AsmParser/LLParser.cpp
index f887372060b..ee634505581 100644
--- a/lib/AsmParser/LLParser.cpp
+++ b/lib/AsmParser/LLParser.cpp
@@ -7519,7 +7519,7 @@ bool LLParser::ParseArgs(std::vector<uint64_t> &Args) {
   return false;
 }
 
-auto FwdVIRef = (GlobalValueSummaryMapTy::value_type *)-8;
+static const auto FwdVIRef = (GlobalValueSummaryMapTy::value_type *)-8;
 
 static void resolveFwdRef(ValueInfo *Fwd, ValueInfo &Resolved) {
   bool ReadOnly = Fwd->isReadOnly();
diff --git a/lib/CodeGen/AsmPrinter/DwarfDebug.cpp b/lib/CodeGen/AsmPrinter/DwarfDebug.cpp
index 151cf3c4247..1de2ffb6cfa 100644
--- a/lib/CodeGen/AsmPrinter/DwarfDebug.cpp
+++ b/lib/CodeGen/AsmPrinter/DwarfDebug.cpp
@@ -2376,8 +2376,8 @@ static void emitRangeList(DwarfDebug &DD, AsmPrinter *Asm,
   }
 }
 
-void emitDebugRangesImpl(DwarfDebug &DD, AsmPrinter *Asm,
-                         const DwarfFile &Holder, MCSymbol *TableEnd) {
+static void emitDebugRangesImpl(DwarfDebug &DD, AsmPrinter *Asm,
+                                const DwarfFile &Holder, MCSymbol *TableEnd) {
   for (const RangeSpanList &List : Holder.getRangeLists())
     emitRangeList(DD, Asm, List);
 
diff --git a/lib/CodeGen/GlobalISel/IRTranslator.cpp b/lib/CodeGen/GlobalISel/IRTranslator.cpp
index 4feb624673d..4db5d1c2ea1 100644
--- a/lib/CodeGen/GlobalISel/IRTranslator.cpp
+++ b/lib/CodeGen/GlobalISel/IRTranslator.cpp
@@ -105,6 +105,7 @@ IRTranslator::IRTranslator() : MachineFunctionPass(ID) {
 }
 
 #ifndef NDEBUG
+namespace {
 /// Verify that every instruction created has the same DILocation as the
 /// instruction being translated.
 class DILocationVerifier : MachineFunction::Delegate {
@@ -131,6 +132,7 @@ public:
   }
   void MF_HandleRemoval(const MachineInstr &MI) override {}
 };
+} // namespace
 #endif // ifndef NDEBUG
 
 
diff --git a/lib/CodeGen/GlobalISel/Legalizer.cpp b/lib/CodeGen/GlobalISel/Legalizer.cpp
index df2dcace421..8f8280a21da 100644
--- a/lib/CodeGen/GlobalISel/Legalizer.cpp
+++ b/lib/CodeGen/GlobalISel/Legalizer.cpp
@@ -73,6 +73,7 @@ static bool isArtifact(const MachineInstr &MI) {
 using InstListTy = GISelWorkList<256>;
 using ArtifactListTy = GISelWorkList<128>;
 
+namespace {
 class LegalizerWorkListManager : public GISelChangeObserver {
   InstListTy &InstList;
   ArtifactListTy &ArtifactList;
@@ -111,6 +112,7 @@ public:
     createdInstr(MI);
   }
 };
+} // namespace
 
 bool Legalizer::runOnMachineFunction(MachineFunction &MF) {
   // If the ISel pipeline failed, do not bother running that pass.
diff --git a/lib/Transforms/IPO/HotColdSplitting.cpp b/lib/Transforms/IPO/HotColdSplitting.cpp
index 5d989a40f65..924a7d5fbd9 100644
--- a/lib/Transforms/IPO/HotColdSplitting.cpp
+++ b/lib/Transforms/IPO/HotColdSplitting.cpp
@@ -295,6 +295,7 @@ Function *HotColdSplitting::extractColdRegion(const BlockSequence &Region,
 /// A pair of (basic block, score).
 using BlockTy = std::pair<BasicBlock *, unsigned>;
 
+namespace {
 /// A maximal outlining region. This contains all blocks post-dominated by a
 /// sink block, the sink block itself, and all blocks dominated by the sink.
 class OutliningRegion {
@@ -458,6 +459,7 @@ public:
     return SubRegion;
   }
 };
+} // namespace
 
 bool HotColdSplitting::outlineColdRegions(Function &F, ProfileSummaryInfo &PSI,
                                           BlockFrequencyInfo *BFI,
diff --git a/lib/Transforms/Instrumentation/GCOVProfiling.cpp b/lib/Transforms/Instrumentation/GCOVProfiling.cpp
index 829123911c6..9af64ed332c 100644
--- a/lib/Transforms/Instrumentation/GCOVProfiling.cpp
+++ b/lib/Transforms/Instrumentation/GCOVProfiling.cpp
@@ -185,7 +185,7 @@ static StringRef getFunctionName(const DISubprogram *SP) {
 /// Prefer relative paths in the coverage notes. Clang also may split
 /// up absolute paths into a directory and filename component. When
 /// the relative path doesn't exist, reconstruct the absolute path.
-SmallString<128> getFilename(const DISubprogram *SP) {
+static SmallString<128> getFilename(const DISubprogram *SP) {
   SmallString<128> Path;
   StringRef RelPath = SP->getFilename();
   if (sys::fs::exists(RelPath))
diff --git a/lib/Transforms/Scalar/LICM.cpp b/lib/Transforms/Scalar/LICM.cpp
index 44ef6ea73ff..d204654c391 100644
--- a/lib/Transforms/Scalar/LICM.cpp
+++ b/lib/Transforms/Scalar/LICM.cpp
@@ -480,6 +480,7 @@ bool llvm::sinkRegion(DomTreeNode *N, AliasAnalysis *AA, LoopInfo *LI,
   return Changed;
 }
 
+namespace {
 // This is a helper class for hoistRegion to make it able to hoist control flow
 // in order to be able to hoist phis. The way this works is that we initially
 // start hoisting to the loop preheader, and when we see a loop invariant branch
@@ -706,6 +707,7 @@ public:
     return HoistDestinationMap[BB];
   }
 };
+} // namespace
 
 /// Walk the specified region of the CFG (defined by all blocks dominated by
 /// the specified block, and that are in the current loop) in depth first
diff --git a/lib/Transforms/Scalar/LoopSimplifyCFG.cpp b/lib/Transforms/Scalar/LoopSimplifyCFG.cpp
index c8461655770..2e5927f9a06 100644
--- a/lib/Transforms/Scalar/LoopSimplifyCFG.cpp
+++ b/lib/Transforms/Scalar/LoopSimplifyCFG.cpp
@@ -80,6 +80,7 @@ static BasicBlock *getOnlyLiveSuccessor(BasicBlock *BB) {
   return nullptr;
 }
 
+namespace {
 /// Helper class that can turn branches and switches with constant conditions
 /// into unconditional branches.
 class ConstantTerminatorFoldingImpl {
@@ -538,6 +539,7 @@ public:
     return true;
   }
 };
+} // namespace
 
 /// Turn branches and switches with known constant conditions into unconditional
 /// branches.