ASTDemangler: Implement types in generic local context

If we nest a type inside a local context inside a generic type,
we have to look through the local context(s) to find the outer
generic type when stripping off generic arguments.

We don't support nominal types inside generic local context
right now, but this can happen with type aliases.

Author: slavapestov

include/swift/Demangling/TypeDecoder.h

@@ -28,11 +28,6 @@
 namespace swift {
 namespace Demangle {
 
-/// Strip generic arguments from the "spine" of a context node, producing a
-/// bare context to be used in (e.g.) forming nominal type descriptors.
-NodePointer stripGenericArgsFromContextNode(NodePointer node,
-                                            NodeFactory &factory);
-
 /// Describe a function parameter, parameterized on the type
 /// representation.
 template <typename BuiltType>
@@ -611,8 +606,7 @@ class TypeDecoder {
         parent = decodeMangledType(parentContext);
         // Remove any generic arguments from the context node, producing a
         // node that references the nominal type declaration.
-        declNode =
-          stripGenericArgsFromContextNode(node, Builder.getNodeFactory());
+        declNode = Demangle::getUnspecialized(node, Builder.getNodeFactory());
         break;
       }
     }

lib/Demangling/CMakeLists.txt

@@ -9,7 +9,6 @@ add_swift_host_library(swiftDemangling
                     OldRemangler.cpp
                     Punycode.cpp
                     Remangler.cpp
-                    TypeDecoder.cpp
                   C_COMPILE_FLAGS
                     -DLLVM_DISABLE_ABI_BREAKING_CHECKS_ENFORCING=1)
 

lib/Demangling/TypeDecoder.cpp

@@ -9,8 +9,7 @@ set(swiftReflection_SOURCES
   "${SWIFT_SOURCE_DIR}/lib/Demangling/NodePrinter.cpp"
   "${SWIFT_SOURCE_DIR}/lib/Demangling/ManglingUtils.cpp"
   "${SWIFT_SOURCE_DIR}/lib/Demangling/Punycode.cpp"
-  "${SWIFT_SOURCE_DIR}/lib/Demangling/Remangler.cpp"
-  "${SWIFT_SOURCE_DIR}/lib/Demangling/TypeDecoder.cpp")
+  "${SWIFT_SOURCE_DIR}/lib/Demangling/Remangler.cpp")
 
 # When we're building with assertions, include the demangle node dumper to aid
 # in debugging.

stdlib/public/Reflection/CMakeLists.txt

@@ -26,7 +26,6 @@ set(swift_runtime_objc_sources
     ObjCRuntimeGetImageNameFromClass.mm
     "${SWIFT_SOURCE_DIR}/lib/Demangling/OldRemangler.cpp"
     "${SWIFT_SOURCE_DIR}/lib/Demangling/Remangler.cpp"
-    "${SWIFT_SOURCE_DIR}/lib/Demangling/TypeDecoder.cpp"
     )
 
 set(swift_runtime_sources

stdlib/public/runtime/CMakeLists.txt

@@ -246,7 +246,7 @@ _findExtendedTypeContextDescriptor(const ExtensionContextDescriptor *extension,
       return nullptr;
     node = node->getChild(0);
   }
-  node = stripGenericArgsFromContextNode(node, demangler);
+  node = Demangle::getUnspecialized(node, demangler);
 
   return _findNominalTypeDescriptor(node, demangler);
 }

stdlib/public/runtime/MetadataLookup.cpp

@@ -0,0 +1,155 @@
+// RUN: %empty-directory(%t)
+
+// RUN: %target-build-swift -emit-executable %s -g -o %t/generic_local_types -emit-module
+// RUN: sed -ne '/\/\/ *DEMANGLE: /s/\/\/ *DEMANGLE: *//p' < %s > %t/input
+// RUN: %lldb-moduleimport-test %t/generic_local_types -type-from-mangled=%t/input | %FileCheck %s
+
+func blackHole(_: Any...) {}
+
+class Generic<T> {
+  // Initializer -> closure
+  var x1: Int = {
+    typealias Alias1 = Int
+    let a: Alias1 = 0
+    return a
+  }()
+
+  // Implicit getter
+  var x2: Int {
+    typealias Alias2 = Int
+    let a: Alias2 = 0
+    return a
+  }
+
+  // Observers
+  var x3: Int = 0 {
+    didSet {
+      typealias Alias3 = Int
+      let a: Alias3 = 0
+      blackHole(a)
+    }
+    willSet {
+      typealias Alias4 = Int
+      let a: Alias4 = 0
+      blackHole(a)
+    }
+  }
+
+  // Getter and setter
+  var x4: Int {
+    get {
+      typealias Alias5 = Int
+      let a: Alias5 = 0
+      return a
+    }
+    set {
+      typealias Alias6 = Int
+      let a: Alias6 = 0
+      blackHole(a)
+    }
+  }
+
+  // Read and modify
+  var x5: Int {
+    _read {
+      typealias Alias7 = Int
+      let a: Alias7 = 0
+      yield a
+    }
+    _modify {
+      typealias Alias8 = Int
+      var a: Alias8 = 0
+      yield &a
+    }
+  }
+
+  // Subscript implicit getter
+  subscript(x x: Int) -> Int {
+    typealias Alias9 = Int
+    let a: Alias9 = 0
+    return a
+  }
+
+  // Subscript getter and setter
+  subscript(y y: Int) -> Int {
+    get {
+      typealias Alias10 = Int
+      let a: Alias10 = 0
+      return a
+    }
+    set {
+      typealias Alias11 = Int
+      let a: Alias11 = 0
+      blackHole(a)
+    }
+  }
+
+  // Function -> default argument -> closure
+  func method(_: Int = {
+    typealias Alias12 = Int
+    let a: Alias12 = 0
+    return a
+  }()) {
+    // Function
+    typealias Alias13 = Int
+    let a: Alias13 = 0
+
+    blackHole(a)
+
+    // Function -> function
+    func nested() {
+      typealias Alias = Int
+      let a: Alias = 0
+
+      blackHole(a)
+    }
+  }
+
+  // Constructor
+  init() {
+    typealias Alias14 = Int
+    let a: Alias14 = 0
+
+    blackHole(a)
+  }
+
+  // Destructor
+  deinit {
+    typealias Alias15 = Int
+    let a: Alias15 = 0
+
+    blackHole(a)
+  }
+}
+
+// DEMANGLE: $s19generic_local_types7GenericC2x1SivpfiSiyXEfU_6Alias1L_ayx_GD
+// DEMANGLE: $s19generic_local_types7GenericC2x2Sivg6Alias2L_ayx__GD
+// DEMANGLE: $s19generic_local_types7GenericC2x3SivW6Alias3L_ayx__GD
+// DEMANGLE: $s19generic_local_types7GenericC2x3Sivw6Alias4L_ayx__GD
+// DEMANGLE: $s19generic_local_types7GenericC2x4Sivg6Alias5L_ayx__GD
+// DEMANGLE: $s19generic_local_types7GenericC2x4Sivs6Alias6L_ayx__GD
+// DEMANGLE: $s19generic_local_types7GenericC2x5Sivr6Alias7L_ayx__GD
+// DEMANGLE: $s19generic_local_types7GenericC2x5SivM6Alias8L_ayx__GD
+// DEMANGLE: $s19generic_local_types7GenericC1xS2i_tcig6Alias9L_ayx__GD
+// DEMANGLE: $s19generic_local_types7GenericC1yS2i_tcig7Alias10L_ayx__GD
+// DEMANGLE: $s19generic_local_types7GenericC1yS2i_tcis7Alias11L_ayx__GD
+// DEMANGLE: $s19generic_local_types7GenericC6methodyySiFfA_SiycfU_7Alias12L_ayx__GD
+// DEMANGLE: $s19generic_local_types7GenericC6methodyySiF7Alias13L_ayx__GD
+// DEMANGLE: $s19generic_local_types7GenericCACyxGycfc7Alias14L_ayx__GD
+// DEMANGLE: $s19generic_local_types7GenericCfd7Alias15L_ayx__GD
+
+// CHECK: Alias1
+// CHECK: Alias2
+// CHECK: Alias3
+// CHECK: Alias4
+// CHECK: Alias5
+// CHECK: Alias6
+// CHECK: Alias7
+// CHECK: Alias8
+// CHECK: Alias9
+// CHECK: Alias10
+// CHECK: Alias11
+// CHECK: Alias12
+// CHECK: Alias13
+// CHECK: Alias14
+// CHECK: Alias15