Merge pull request #2050 from adrian-prantl/tuple-elem-next

Add a TypeSystemSwiftTypeRef::GetTupleElementName() method.

Author: adrian-prantl

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

@@ -203,6 +203,30 @@ ResolveTypeAlias(SwiftASTContext *module_holder,
   return {n, {}};
 }
 
+std::string
+TypeSystemSwiftTypeRef::GetTupleElementName(lldb::opaque_compiler_type_t type,
+                                            size_t idx) {
+  using namespace swift::Demangle;
+  Demangler dem;
+  NodePointer node = TypeSystemSwiftTypeRef::DemangleCanonicalType(dem, type);
+  if (!node || node->getKind() != Node::Kind::Tuple)
+    return "";
+  if (node->getNumChildren() < idx)
+    return "";
+  NodePointer child = node->getChild(idx);
+  if (child->getNumChildren() != 1 &&
+      child->getKind() != Node::Kind::TupleElement)
+    return "";
+  for (NodePointer name : *child) {
+    if (name->getKind() != Node::Kind::TupleElementName)
+      continue;
+    return name->getText().str();
+  }
+  std::string name;
+  llvm::raw_string_ostream(name) << idx;
+  return name;
+}
+
 swift::Demangle::NodePointer TypeSystemSwiftTypeRef::Transform(
     swift::Demangle::Demangler &dem, swift::Demangle::NodePointer node,
     std::function<swift::Demangle::NodePointer(swift::Demangle::NodePointer)>

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

@@ -257,6 +257,10 @@ class TypeSystemSwiftTypeRef : public TypeSystemSwift {
       bool print_help_if_available, bool print_extensions_if_available,
       lldb::DescriptionLevel level = lldb::eDescriptionLevelFull) override;
 
+  /// Return the nth tuple element's name, if it has one.
+  std::string GetTupleElementName(lldb::opaque_compiler_type_t type,
+                                  size_t idx);
+
   /// Recursively transform the demangle tree starting a \p node by
   /// doing a post-order traversal and replacing each node with
   /// fn(node).

lldb/unittests/Symbol/TestTypeSystemSwiftTypeRef.cpp

@@ -402,6 +402,20 @@ TEST_F(TestTypeSystemSwiftTypeRef, Tuple) {
     ASSERT_EQ(float_int_tuple.GetMangledTypeName(),
               "$ss0019BuiltinFPIEEE_CJEEdV1f_s0016BuiltinInt_gCJAcV1itD");
   }
+  {
+    NodePointer n = b.GlobalType(
+        b.Node(Node::Kind::Tuple,
+               b.Node(Node::Kind::TupleElement,
+                      b.Node(Node::Kind::TupleElementName, "x"), b.IntType()),
+               b.Node(Node::Kind::TupleElement, b.IntType()),
+               b.Node(Node::Kind::TupleElement,
+                      b.Node(Node::Kind::TupleElementName, "z"), b.IntType())));
+    CompilerType t = GetCompilerType(b.Mangle(n));
+    lldb::opaque_compiler_type_t o = t.GetOpaqueQualType();
+    ASSERT_EQ(m_swift_ts.GetTupleElementName(o, 0), "x");
+    ASSERT_EQ(m_swift_ts.GetTupleElementName(o, 1), "1");
+    ASSERT_EQ(m_swift_ts.GetTupleElementName(o, 2), "z");
+  }
 }
 
 TEST_F(TestTypeSystemSwiftTypeRef, TypeClass) {