[lldb] Add missing recursion when desugaring a type

The type canonicalization would early-exit when desugaring of an outer
node was successful, which means that GetCanonicalNode() would behave
like DemangleCanonicalOutermostType() for types like sugared Optionals.

rdar://149273756

Author: adrian-prantl

lldb/source/Plugins/TypeSystem/Swift/TypeSystemSwiftTypeRef.cpp

@@ -1295,9 +1295,7 @@ TypeSystemSwiftTypeRef::GetCanonicalNode(swift::Demangle::Demangler &dem,
   // SomeAlias<WhatSomeOtherAliasResolvesTo> because it tries to
   // preserve all sugar.
   using namespace swift::Demangle;
-  NodePointer transformed = Canonicalize(dem, node, flavor);
-  if (node != transformed)
-    return transformed;
+  node = Canonicalize(dem, node, flavor);
 
   llvm::SmallVector<NodePointer, 2> children;
   bool changed = false;

lldb/source/Plugins/TypeSystem/Swift/TypeSystemSwiftTypeRef.h

@@ -67,7 +67,10 @@ class TypeSystemSwiftTypeRef : public TypeSystemSwift {
   /// \}
 
   /// Provided only for unit tests.
+  /// \{
+  friend struct TestTypeSystemSwiftTypeRef;
   TypeSystemSwiftTypeRef();
+  /// \}
   ~TypeSystemSwiftTypeRef();
   TypeSystemSwiftTypeRef(Module &module);
   /// Get the corresponding SwiftASTContext, and create one if necessary.

lldb/test/API/lang/swift/clangimporter/objc_optional_dict/Makefile

@@ -0,0 +1,3 @@
+SWIFT_SOURCES := main.swift
+
+include Makefile.rules

lldb/test/API/lang/swift/clangimporter/objc_optional_dict/TestSwiftObjCOptionalDict.py

@@ -0,0 +1,17 @@
+import lldb
+from lldbsuite.test.lldbtest import *
+from lldbsuite.test.decorators import *
+import lldbsuite.test.lldbutil as lldbutil
+
+class TestSwiftObjCOptionalDict(TestBase):
+    @skipUnlessDarwin
+    @swiftTest
+    def test(self):
+        self.build()
+        lldbutil.run_to_source_breakpoint(
+            self, 'break here', lldb.SBFileSpec('main.swift'))
+
+        # This should from DWRAF, without loading a Swift module.
+        self.expect("settings set symbols.swift-typesystem-compiler-fallback false")
+        d = self.frame().FindVariable("dict")
+        lldbutil.check_variable(self, d, summary='0 key/value pairs', value='some')

lldb/test/API/lang/swift/clangimporter/objc_optional_dict/main.swift

@@ -0,0 +1,7 @@
+import Foundation
+func f() {
+  var dict : [NSKeyValueChangeKey : Any]? = [:]
+  print("break here")
+}
+
+f()

lldb/unittests/Symbol/TestTypeSystemSwiftTypeRef.cpp

@@ -23,6 +23,7 @@ using namespace lldb;
 using namespace lldb_private;
 using namespace llvm;
 
+namespace lldb_private {
 struct TestTypeSystemSwiftTypeRef : public testing::Test {
   std::shared_ptr<TypeSystemSwiftTypeRef> m_swift_ts;
 
@@ -32,7 +33,13 @@ struct TestTypeSystemSwiftTypeRef : public testing::Test {
     ConstString internalized(mangled_name);
     return m_swift_ts->GetTypeFromMangledTypename(internalized);
   }
+  swift::Demangle::NodePointer
+  DemangleCanonicalOutermostType(swift::Demangle::Demangler &dem,
+                                 lldb::opaque_compiler_type_t type) {
+    return m_swift_ts->DemangleCanonicalOutermostType(dem, type);
+  }
 };
+} // namespace lldb_private
 
 /// Helper class to conveniently construct demangle tree hierarchies.
 class NodeBuilder {
@@ -79,6 +86,15 @@ class NodeBuilder {
              Node(Node::Kind::Module, swift::STDLIB_NAME),
              Node(Node::Kind::Identifier, swift::BUILTIN_TYPE_NAME_FLOAT)));
   }
+  NodePointer DesugaredOptionalType(NodePointer type) {
+    return Node(Node::Kind::Type,
+                Node(Node::Kind::BoundGenericEnum,
+                     Node(Node::Kind::Type,
+                          Node(Node::Kind::Enum,
+                               Node(Node::Kind::Module, swift::STDLIB_NAME),
+                               Node(Node::Kind::Identifier, "Optional"))),
+                     Node(Node::Kind::TypeList, type)));
+  }
   NodePointer GlobalTypeMangling(NodePointer type) {
     assert(type && type->getKind() == Node::Kind::Type);
     return Node(Node::Kind::Global, Node(Node::Kind::TypeMangling, type));
@@ -1025,3 +1041,42 @@ TEST_F(TestTypeSystemSwiftTypeRef, Error) {
     ASSERT_TRUE(m_swift_ts->ContainsError(opaque));
   }
 }
+
+TEST_F(TestTypeSystemSwiftTypeRef, Canonicalize) {
+  using namespace swift::Demangle;
+  Demangler dem;
+  NodeBuilder b(dem);
+  {
+    {
+      NodePointer n0 =
+          b.GlobalType(b.Node(Node::Kind::SugaredOptional, b.IntType()));
+      NodePointer n1 =
+          b.GlobalTypeMangling(b.DesugaredOptionalType(b.IntType()));
+      CompilerType sugared = GetCompilerType(b.Mangle(n0));
+      CompilerType desugared = GetCompilerType(b.Mangle(n1));
+      ASSERT_EQ(sugared.GetCanonicalType().GetMangledTypeName(),
+                desugared.GetMangledTypeName());
+    }
+    {
+      NodePointer n0 = b.GlobalType(
+          b.Node(Node::Kind::SugaredOptional,
+                 b.Node(Node::Kind::Type,
+                        b.Node(Node::Kind::SugaredOptional, b.IntType()))));
+      NodePointer n1 = b.GlobalTypeMangling(
+          b.DesugaredOptionalType(b.DesugaredOptionalType(b.IntType())));
+      CompilerType sugared = GetCompilerType(b.Mangle(n0));
+      CompilerType desugared = GetCompilerType(b.Mangle(n1));
+      ASSERT_EQ(sugared.GetCanonicalType().GetMangledTypeName(),
+                desugared.GetMangledTypeName());
+
+      NodePointer n2 = b.GlobalType(
+          DemangleCanonicalOutermostType(dem, sugared.GetOpaqueQualType()));
+      NodePointer n3 = b.GlobalTypeMangling(b.DesugaredOptionalType(
+          b.Node(Node::Kind::SugaredOptional, b.IntType())));
+      CompilerType single_desugared2 = GetCompilerType(b.Mangle(n2));
+      CompilerType single_desugared3 = GetCompilerType(b.Mangle(n3));
+      ASSERT_EQ(single_desugared2.GetMangledTypeName(),
+                single_desugared3.GetMangledTypeName());
+    }
+  }
+}