[lldb][Formatter] Consolidate libstdc++ and libc++ unique_ptr formatter tests into generic test

The libc++ test was a subset of the tests in libstdc++. This test moves
the libc++ test into `generic` and somne additional test-cases from `libstdc++`
(specifically the recursive unique_ptr case). It turns out the libstdc++
formatter supports dereferencing using the "object" or "obj" names. We
could either drop those from the tests or support the same for libc++. I
took the latter approach but don't have strong opinions on this.

Split out from #146740

Author: Michael137

lldb/source/Plugins/Language/CPlusPlus/LibCxx.cpp

@@ -399,7 +399,7 @@ lldb_private::formatters::LibcxxUniquePtrSyntheticFrontEnd::
     return 0;
   if (name == "deleter")
     return 1;
-  if (name == "$$dereference$$")
+  if (name == "obj" || name == "object" || name == "$$dereference$$")
     return 2;
   return llvm::createStringError("Type has no child named '%s'",
                                  name.AsCString());

lldb/test/API/functionalities/data-formatter/data-formatter-stl/libcxx/unique_ptr/Makefile renamed to lldb/test/API/functionalities/data-formatter/data-formatter-stl/generic/unique_ptr/Makefile

@@ -1,7 +1,5 @@
 CXX_SOURCES := main.cpp
 
-USE_LIBCPP := 1
-
 # We need debug info tuning for lldb in order to emit the preferred name for
 # std::string. See https://reviews.llvm.org/D145803.
 CXXFLAGS_EXTRAS := -std=c++14 -glldb

lldb/test/API/functionalities/data-formatter/data-formatter-stl/libcxx/unique_ptr/TestDataFormatterLibcxxUniquePtr.py renamed to lldb/test/API/functionalities/data-formatter/data-formatter-stl/generic/unique_ptr/TestDataFormatterStdUniquePtr.py

@@ -1,8 +1,7 @@
 """
-Test lldb data formatter for libc++ std::unique_ptr.
+Test lldb data formatter for std::unique_ptr.
 """
 
-
 import lldb
 from lldbsuite.test.decorators import *
 from lldbsuite.test.lldbtest import *
@@ -32,10 +31,8 @@ def make_expected_basic_string_ptr(self) -> str:
                 "std::default_delete<std::basic_string<char, std::char_traits<char>, std::allocator<char> > > >"
             )
 
-    @add_test_categories(["libc++"])
-    def test_unique_ptr_variables(self):
+    def do_test(self):
         """Test `frame variable` output for `std::unique_ptr` types."""
-        self.build()
 
         lldbutil.run_to_source_breakpoint(
             self, "// break here", lldb.SBFileSpec("main.cpp")
@@ -121,3 +118,67 @@ def test_unique_ptr_variables(self):
         self.expect_var_path("ptr_node->next->value", value="2")
         self.expect_var_path("(*ptr_node).value", value="1")
         self.expect_var_path("(*(*ptr_node).next).value", value="2")
+
+    @add_test_categories(["libstdcxx"])
+    def test_libstdcxx(self):
+        self.build(dictionary={"USE_LIBSTDCPP": 1})
+        self.do_test()
+
+    @add_test_categories(["libc++"])
+    def test_libcxx(self):
+        self.build(dictionary={"USE_LIBCPP": 1})
+        self.do_test()
+
+    def do_test_recursive_unique_ptr(self):
+        # Tests that LLDB can handle when we have a loop in the unique_ptr
+        # reference chain and that it correctly handles the different options
+        # for the frame variable command in this case.
+        self.runCmd("file " + self.getBuildArtifact("a.out"), CURRENT_EXECUTABLE_SET)
+
+        lldbutil.run_break_set_by_source_regexp(self, "Set break point at this line.")
+        self.runCmd("run", RUN_SUCCEEDED)
+        self.expect(
+            "thread list",
+            STOPPED_DUE_TO_BREAKPOINT,
+            substrs=["stopped", "stop reason = breakpoint"],
+        )
+
+        self.expect("frame variable f1->next", substrs=["next = NodeU @"])
+        self.expect(
+            "frame variable --ptr-depth=1 f1->next",
+            substrs=["next = NodeU @", "value = 2"],
+        )
+        self.expect(
+            "frame variable --ptr-depth=2 f1->next",
+            substrs=["next = NodeU @", "value = 1", "value = 2"],
+        )
+
+        frame = self.frame()
+        self.assertTrue(frame.IsValid())
+        self.assertEqual(
+            2,
+            frame.GetValueForVariablePath("f1->next.object.value").GetValueAsUnsigned(),
+        )
+        self.assertEqual(
+            2, frame.GetValueForVariablePath("f1->next->value").GetValueAsUnsigned()
+        )
+        self.assertEqual(
+            1,
+            frame.GetValueForVariablePath(
+                "f1->next.object.next.obj.value"
+            ).GetValueAsUnsigned(),
+        )
+        self.assertEqual(
+            1,
+            frame.GetValueForVariablePath("f1->next->next->value").GetValueAsUnsigned(),
+        )
+
+    @add_test_categories(["libstdcxx"])
+    def test_recursive_unique_ptr_libstdcxx(self):
+        self.build(dictionary={"USE_LIBSTDCPP": 1})
+        self.do_test_recursive_unique_ptr()
+
+    @add_test_categories(["libc++"])
+    def test_recursive_unique_ptr_libcxx(self):
+        self.build(dictionary={"USE_LIBCPP": 1})
+        self.do_test_recursive_unique_ptr()

lldb/test/API/functionalities/data-formatter/data-formatter-stl/libcxx/unique_ptr/main.cpp renamed to lldb/test/API/functionalities/data-formatter/data-formatter-stl/generic/unique_ptr/main.cpp

@@ -15,11 +15,20 @@ struct NodeU {
 // representation when the type of the second element is an empty class. So
 // we need a deleter class with a dummy data member to trigger the other path.
 struct NonEmptyIntDeleter {
-  void operator()(int* ptr) { delete ptr; }
+  void operator()(int *ptr) { delete ptr; }
 
   int dummy_ = 9999;
 };
 
+static void recursive() {
+  // Set up a structure where we have a loop in the unique_ptr chain.
+  NodeU *f1 = new NodeU{nullptr, 1};
+  NodeU *f2 = new NodeU{nullptr, 2};
+  f1->next.reset(f2);
+  f2->next.reset(f1);
+  std::puts("Set break point at this line.");
+}
+
 int main() {
   std::unique_ptr<int> up_empty;
   std::unique_ptr<int> up_int = std::make_unique<int>(10);
@@ -33,5 +42,9 @@ int main() {
       std::unique_ptr<NodeU>(new NodeU{nullptr, 2});
   ptr_node = std::unique_ptr<NodeU>(new NodeU{std::move(ptr_node), 1});
 
-  return 0; // break here
+  std::puts("// break here");
+
+  recursive();
+
+  return 0;
 }