Index: lit/SymbolFile/NativePDB/Inputs/ast-types.lldbinit
===================================================================
--- lit/SymbolFile/NativePDB/Inputs/ast-types.lldbinit
+++ lit/SymbolFile/NativePDB/Inputs/ast-types.lldbinit
@@ -10,11 +10,16 @@
 target variable AC0
 target variable ACNeg1
 
+target variable AC1D
 target variable AC0D
 target variable ACNeg1D
 target variable AD
 target variable ADE
 
+target variable AnonInt
+target variable AnonABCVoid
+target variable AnonABCVoidD
+
 target modules dump ast
 
 quit
Index: lit/SymbolFile/NativePDB/ast-types.cpp
===================================================================
--- lit/SymbolFile/NativePDB/ast-types.cpp
+++ lit/SymbolFile/NativePDB/ast-types.cpp
@@ -72,15 +72,18 @@
 A::C<0> AC0;
 A::C<-1> ACNeg1;
 
+// FIXME: The type `D` is located now at the level of the translation unit.
+// FIXME: Should be located in the namespace `A`, in the struct `C<1>`.
+A::C<1>::D AC1D;
+
 A::C<0>::D AC0D;
 A::C<-1>::D ACNeg1D;
 A::D AD;
 A::D::E ADE;
 
-// FIXME: Anonymous namespaces aren't working correctly.
 Anonymous<int> AnonInt;
 Anonymous<A::B::C<void>> AnonABCVoid;
-Anonymous<A::B::C<int>>::D AnonABCVoidD;
+Anonymous<A::B::C<void>>::D AnonABCVoidD;
 
 // FIXME: Enum size isn't being correctly determined.
 // FIXME: Can't read memory for variable values.
@@ -98,6 +101,9 @@
 // CHECK: (A::C<-1>::D) ACNeg1D = (ACDMember = 0, CPtr = 0x{{0+}})
 // CHECK: (A::D) AD = {}
 // CHECK: (A::D::E) ADE = (ADDMember = 0)
+// CHECK: ((anonymous namespace)::Anonymous<int>) AnonInt = (AnonymousMember = 0)
+// CHECK: ((anonymous namespace)::Anonymous<A::B::C<void>>) AnonABCVoid = (AnonymousMember = 0)
+// CHECK: ((anonymous namespace)::Anonymous<A::B::C<void>>::D) AnonABCVoidD = (AnonymousDMember = 0)
 // CHECK: Dumping clang ast for 1 modules.
 // CHECK: TranslationUnitDecl {{.*}}
 // CHECK: |-CXXRecordDecl {{.*}} class TrivialC definition
@@ -125,7 +131,18 @@
 // CHECK: | `-CXXRecordDecl {{.*}} struct D definition
 // CHECK: |   `-CXXRecordDecl {{.*}} struct E definition
 // CHECK: |     `-FieldDecl {{.*}} ADDMember 'int'
+// CHECK: |-NamespaceDecl
+// CHECK: | |-CXXRecordDecl {{.*}} struct Anonymous<int> definition
+// CHECK: | | `-FieldDecl {{.*}} AnonymousMember 'int'
+// CHECK: | `-CXXRecordDecl {{.*}} struct Anonymous<A::B::C<void>> definition
+// CHECK: |   |-FieldDecl {{.*}} AnonymousMember 'int'
+// CHECK: |   `-CXXRecordDecl {{.*}} struct D definition
+// CHECK: |     `-FieldDecl {{.*}} AnonymousDMember 'int'
 
 int main(int argc, char **argv) {
+  AnonInt.AnonymousMember = 1;
+  AnonABCVoid.AnonymousMember = 2;
+  AnonABCVoidD.AnonymousDMember = 3;
+
   return 0;
 }
Index: lit/SymbolFile/NativePDB/typedefs.cpp
===================================================================
--- lit/SymbolFile/NativePDB/typedefs.cpp
+++ lit/SymbolFile/NativePDB/typedefs.cpp
@@ -54,7 +54,7 @@
 }
 
 
-// CHECK:      namespace `anonymous namespace' {
+// CHECK:      namespace  {
 // CHECK-NEXT:     typedef bool AnonNamespaceTypedef;
 // CHECK-NEXT: }
 // CHECK-NEXT: typedef unsigned long ULongArrayTypedef[10];
Index: lit/SymbolFile/PDB/ast-restore.test
===================================================================
--- lit/SymbolFile/PDB/ast-restore.test
+++ lit/SymbolFile/PDB/ast-restore.test
@@ -1,6 +1,7 @@
 REQUIRES: system-windows, msvc
 RUN: %build --compiler=msvc --nodefaultlib --output=%t.exe %S/Inputs/AstRestoreTest.cpp
-RUN: lldb-test symbols -dump-ast %t.exe | FileCheck --check-prefix=ENUM %s
+RUN: env LLDB_USE_NATIVE_PDB_READER=0 lldb-test symbols -dump-ast %t.exe | FileCheck --check-prefix=ENUM %s
+RUN: env LLDB_USE_NATIVE_PDB_READER=1 lldb-test symbols -dump-ast %t.exe | FileCheck --check-prefix=ENUM %s
 RUN: lldb-test symbols -dump-ast %t.exe | FileCheck --check-prefix=GLOBAL %s
 RUN: lldb-test symbols -dump-ast %t.exe | FileCheck --check-prefix=BASE %s
 RUN: lldb-test symbols -dump-ast %t.exe | FileCheck --check-prefix=CLASS %s
Index: source/Plugins/SymbolFile/NativePDB/PdbAstBuilder.cpp
===================================================================
--- source/Plugins/SymbolFile/NativePDB/PdbAstBuilder.cpp
+++ source/Plugins/SymbolFile/NativePDB/PdbAstBuilder.cpp
@@ -205,6 +205,10 @@
   return std::move(child);
 }
 
+static bool IsAnonymousNamespaceName(llvm::StringRef name) {
+  return name == "`anonymous namespace'" || name == "`anonymous-namespace'";
+}
+
 PdbAstBuilder::PdbAstBuilder(ObjectFile &obj, PdbIndex &index)
     : m_index(index), m_clang(GetClangASTContext(obj)) {
   BuildParentMap();
@@ -256,7 +260,7 @@
     for (llvm::ms_demangle::Node *scope : scopes) {
       auto *nii = static_cast<llvm::ms_demangle::NamedIdentifierNode *>(scope);
       std::string str = nii->toString();
-      context = m_clang.GetUniqueNamespaceDeclaration(str.c_str(), context);
+      context = GetOrCreateNamespaceDecl(str.c_str(), *context);
     }
     return {context, uname};
   }
@@ -525,7 +529,7 @@
   // If that fails, treat it as a series of namespaces.
   for (const MSVCUndecoratedNameSpecifier &spec : specs) {
     std::string ns_name = spec.GetBaseName().str();
-    context = m_clang.GetUniqueNamespaceDeclaration(ns_name.c_str(), context);
+    context = GetOrCreateNamespaceDecl(ns_name.c_str(), *context);
   }
   return {context, uname};
 }
@@ -568,7 +572,7 @@
   clang::DeclContext *context = &GetTranslationUnitDecl();
   while (!name_components.empty()) {
     std::string ns = name_components.front()->toString();
-    context = m_clang.GetUniqueNamespaceDeclaration(ns.c_str(), context);
+    context = GetOrCreateNamespaceDecl(ns.c_str(), *context);
     name_components = name_components.drop_front();
   }
   return context;
@@ -807,7 +811,8 @@
 clang::NamespaceDecl *
 PdbAstBuilder::GetOrCreateNamespaceDecl(llvm::StringRef name,
                                         clang::DeclContext &context) {
-  return m_clang.GetUniqueNamespaceDeclaration(name.str().c_str(), &context);
+  return m_clang.GetUniqueNamespaceDeclaration(
+      IsAnonymousNamespaceName(name) ? nullptr : name.str().c_str(), &context);
 }
 
 clang::BlockDecl *