Demangler: Save state to allow reentrant demangling.

include/swift/Demangling/Demangler.h

@@ -447,7 +447,21 @@ class Demangler : public NodeFactory {
     return popNode();
   }
 
-  void init(StringRef MangledName);
+  /// This class handles preparing the initial state for a demangle job in a reentrant way, pushing the
+  /// existing state back when a demangle job is completed.
+  class DemangleInitRAII {
+    Demangler &Dem;
+    Vector<NodePointer> NodeStack;
+    Vector<NodePointer> Substitutions;
+    int NumWords;
+    StringRef Text;
+    size_t Pos;
+
+  public:
+    DemangleInitRAII(Demangler &Dem, StringRef MangledName);
+    ~DemangleInitRAII();
+  };
+  friend DemangleInitRAII;
 
   void addSubstitution(NodePointer Nd) {
     if (Nd)

lib/Demangling/Demangler.cpp

@@ -492,16 +492,32 @@ void Demangler::clear() {
   NodeFactory::clear();
 }
 
-void Demangler::init(StringRef MangledName) {
-  NodeStack.init(*this, 16);
-  Substitutions.init(*this, 16);
-  NumWords = 0;
-  Text = MangledName;
-  Pos = 0;
+Demangler::DemangleInitRAII::DemangleInitRAII(Demangler &Dem,
+                                              StringRef MangledName)
+// Save the current demangler state so we can restore it.
+  : Dem(Dem),
+    NodeStack(Dem.NodeStack), Substitutions(Dem.Substitutions),
+    NumWords(Dem.NumWords), Text(Dem.Text), Pos(Dem.Pos)
+{
+  // Reset the demangler state for a nested job.
+  Dem.NodeStack.init(Dem, 16);
+  Dem.Substitutions.init(Dem, 16);
+  Dem.NumWords = 0;
+  Dem.Text = MangledName;
+  Dem.Pos = 0;
+}
+
+Demangler::DemangleInitRAII::~DemangleInitRAII() {
+  // Restore the saved state.
+  Dem.NodeStack = NodeStack;
+  Dem.Substitutions = Substitutions;
+  Dem.NumWords = NumWords;
+  Dem.Text = Text;
+  Dem.Pos = Pos;
 }
-  
+
 NodePointer Demangler::demangleSymbol(StringRef MangledName) {
-  init(MangledName);
+  DemangleInitRAII state(*this, MangledName);
 
   // Demangle old-style class and protocol names, which are still used in the
   // ObjC metadata.
@@ -546,7 +562,7 @@ NodePointer Demangler::demangleSymbol(StringRef MangledName) {
 }
 
 NodePointer Demangler::demangleType(StringRef MangledName) {
-  init(MangledName);
+  DemangleInitRAII state(*this, MangledName);
 
   parseAndPushNodes();
 

lib/SILOptimizer/Utils/SpecializationMangler.cpp

@@ -33,7 +33,7 @@ class AttributeDemangler : public Demangle::Demangler {
 public:
   void demangleAndAddAsChildren(StringRef MangledSpecialization,
                                 NodePointer Parent) {
-    init(MangledSpecialization);
+    DemangleInitRAII state(*this, MangledSpecialization);
     if (!parseAndPushNodes()) {
       llvm::errs() << "Can't demangle: " << MangledSpecialization << '\n';
       abort();

test/Reflection/Inputs/ConcreteTypes.swift

@@ -63,3 +63,11 @@ public struct References {
   public unowned var unownedRef: C
   public unowned(unsafe) var unownedUnsafeRef: C
 }
+
+private struct PrivateStructField {
+  var x: Int16
+}
+
+public struct HasArrayOfPrivateStructField {
+  private var x: [PrivateStructField]
+}

test/Reflection/typeref_decoding.swift

@@ -1,6 +1,6 @@
 // REQUIRES: no_asan
 // RUN: %empty-directory(%t)
-// RUN: %target-build-swift %S/Inputs/ConcreteTypes.swift %S/Inputs/GenericTypes.swift %S/Inputs/Protocols.swift %S/Inputs/Extensions.swift %S/Inputs/Closures.swift -parse-as-library -emit-module -emit-library -module-name TypesToReflect -o %t/%target-library-name(TypesToReflect)
+// RUN: %target-build-swift -Xfrontend -enable-anonymous-context-mangled-names %S/Inputs/ConcreteTypes.swift %S/Inputs/GenericTypes.swift %S/Inputs/Protocols.swift %S/Inputs/Extensions.swift %S/Inputs/Closures.swift -parse-as-library -emit-module -emit-library -module-name TypesToReflect -o %t/%target-library-name(TypesToReflect)
 // RUN: %target-swift-reflection-dump -binary-filename %t/%target-library-name(TypesToReflect) | %FileCheck %s
 
 // CHECK: FIELDS:
@@ -201,6 +201,13 @@
 // CHECK: (unmanaged_storage
 // CHECK:   (class TypesToReflect.C))
 
+// CHECK: TypesToReflect.(PrivateStructField
+// CHECK: ----------------------------------
+
+// CHECK: TypesToReflect.HasArrayOfPrivateStructField
+// CHECK: -------------------------------------------
+// CHECK: x: Swift.Array<TypesToReflect.(PrivateStructField{{.*}})>
+
 // CHECK: TypesToReflect.C1
 // CHECK: -----------------
 // CHECK: aClass: TypesToReflect.C1<A>
@@ -652,14 +659,14 @@
 // CHECK: TypesToReflect.ClassBoundP
 // CHECK: --------------------------
 
-// CHECK: TypesToReflect.(FileprivateProtocol in _{{[0-9a-fA-F]+}})
+// CHECK: TypesToReflect.(FileprivateProtocol in {{.*}})
 // CHECK: -------------------------------------------------------------------------
 
 // CHECK: TypesToReflect.HasFileprivateProtocol
 // CHECK: -------------------------------------
-// CHECK: x: TypesToReflect.(FileprivateProtocol in ${{[0-9a-fA-F]+}})
+// CHECK: x: TypesToReflect.(FileprivateProtocol in {{.*}})
 // CHECK: (protocol_composition
-// CHECK-NEXT: (protocol TypesToReflect.(FileprivateProtocol in ${{[0-9a-fA-F]+}})))
+// CHECK-NEXT: (protocol TypesToReflect.(FileprivateProtocol in {{.*}})))
 
 // CHECK: ASSOCIATED TYPES:
 // CHECK: =================