[lldb][Test] Add C++ tests for DumpValueObjectOptions and enums (#93158)

DumpValueObjectOptions can only be created and modified from C++. This
means it's currently only testable from Python by calling some command
that happens to use one, and even so, you can't pick which options get
chosen.

So we have decent coverage for the major options that way, but I want to
add more niche options that will be harder to test from Python (register
field options).

So this change adds some "unit tests", though it's stretching the
definition to the point it's more "test written in C++". So we can test
future options in isolation.

Since I want to add options specific to enums, that's all it covers.
There is a test class that sets up the type system so it will be easy to
test other types in future (e.g. structs, which register fields also
use).

lldb/unittests/CMakeLists.txt

@@ -73,6 +73,7 @@ add_subdirectory(tools)
 add_subdirectory(UnwindAssembly)
 add_subdirectory(Utility)
 add_subdirectory(Thread)
+add_subdirectory(ValueObject)
 
 if(LLDB_CAN_USE_DEBUGSERVER AND LLDB_TOOL_DEBUGSERVER_BUILD AND NOT LLDB_USE_SYSTEM_DEBUGSERVER)
   add_subdirectory(debugserver)

lldb/unittests/ValueObject/CMakeLists.txt

@@ -0,0 +1,10 @@
+add_lldb_unittest(LLDBValueObjectTests
+  DumpValueObjectOptionsTests.cpp
+
+  LINK_LIBS
+    lldbPluginPlatformLinux
+    lldbPluginScriptInterpreterNone
+
+  LINK_COMPONENTS
+    Support
+  )

lldb/unittests/ValueObject/DumpValueObjectOptionsTests.cpp

@@ -0,0 +1,176 @@
+//===-- DumpValueObjectOptionsTests.cpp -----------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#include "Plugins/Platform/Linux/PlatformLinux.h"
+#include "Plugins/ScriptInterpreter/None/ScriptInterpreterNone.h"
+#include "Plugins/TypeSystem/Clang/TypeSystemClang.h"
+#include "TestingSupport/SubsystemRAII.h"
+#include "TestingSupport/Symbol/ClangTestUtils.h"
+#include "lldb/Core/Debugger.h"
+#include "lldb/Core/ValueObject.h"
+#include "lldb/Core/ValueObjectConstResult.h"
+#include "lldb/DataFormatters/DumpValueObjectOptions.h"
+
+#include "gtest/gtest.h"
+
+using namespace lldb;
+using namespace lldb_private;
+
+struct MockProcess : Process {
+  MockProcess(lldb::TargetSP target_sp, lldb::ListenerSP listener_sp)
+      : Process(target_sp, listener_sp) {}
+
+  llvm::StringRef GetPluginName() override { return "mock process"; }
+
+  bool CanDebug(lldb::TargetSP target, bool plugin_specified_by_name) override {
+    return false;
+  };
+
+  Status DoDestroy() override { return {}; }
+
+  void RefreshStateAfterStop() override {}
+
+  bool DoUpdateThreadList(ThreadList &old_thread_list,
+                          ThreadList &new_thread_list) override {
+    return false;
+  };
+
+  size_t DoReadMemory(lldb::addr_t vm_addr, void *buf, size_t size,
+                      Status &error) override {
+    // No need to read memory in these tests.
+    return size;
+  }
+};
+
+class ValueObjectMockProcessTest : public ::testing::Test {
+public:
+  void SetUp() override {
+    ArchSpec arch("i386-pc-linux");
+    Platform::SetHostPlatform(
+        platform_linux::PlatformLinux::CreateInstance(true, &arch));
+    m_debugger_sp = Debugger::CreateInstance();
+    ASSERT_TRUE(m_debugger_sp);
+    m_debugger_sp->GetTargetList().CreateTarget(*m_debugger_sp, "", arch,
+                                                eLoadDependentsNo,
+                                                m_platform_sp, m_target_sp);
+    ASSERT_TRUE(m_target_sp);
+    ASSERT_TRUE(m_target_sp->GetArchitecture().IsValid());
+    ASSERT_TRUE(m_platform_sp);
+    m_listener_sp = Listener::MakeListener("dummy");
+    m_process_sp = std::make_shared<MockProcess>(m_target_sp, m_listener_sp);
+    ASSERT_TRUE(m_process_sp);
+    m_exe_ctx = ExecutionContext(m_process_sp);
+
+    m_holder = std::make_unique<clang_utils::TypeSystemClangHolder>("test");
+    m_type_system = m_holder->GetAST();
+  }
+
+  CompilerType
+  MakeEnumType(const std::vector<std::pair<const char *, int>> enumerators) {
+    CompilerType uint_type = m_type_system->GetBuiltinTypeForEncodingAndBitSize(
+        lldb::eEncodingUint, 32);
+    CompilerType enum_type = m_type_system->CreateEnumerationType(
+        "TestEnum", m_type_system->GetTranslationUnitDecl(),
+        OptionalClangModuleID(), Declaration(), uint_type, false);
+
+    m_type_system->StartTagDeclarationDefinition(enum_type);
+    Declaration decl;
+    for (auto [name, value] : enumerators)
+      m_type_system->AddEnumerationValueToEnumerationType(enum_type, decl, name,
+                                                          value, 32);
+    m_type_system->CompleteTagDeclarationDefinition(enum_type);
+
+    return enum_type;
+  }
+
+  void TestDumpValueObject(
+      CompilerType enum_type,
+      const std::vector<
+          std::tuple<uint32_t, DumpValueObjectOptions, const char *>> &tests) {
+    StreamString strm;
+    ConstString var_name("test_var");
+    ByteOrder endian = endian::InlHostByteOrder();
+    ExecutionContextScope *exe_scope = m_exe_ctx.GetBestExecutionContextScope();
+    for (auto [value, options, expected] : tests) {
+      DataExtractor data_extractor{&value, sizeof(value), endian, 4};
+      ValueObjectConstResult::Create(exe_scope, enum_type, var_name,
+                                     data_extractor)
+          ->Dump(strm, options);
+      ASSERT_STREQ(strm.GetString().str().c_str(), expected);
+      strm.Clear();
+    }
+  }
+
+  ExecutionContext m_exe_ctx;
+  TypeSystemClang *m_type_system;
+
+private:
+  SubsystemRAII<FileSystem, HostInfo, platform_linux::PlatformLinux,
+                ScriptInterpreterNone>
+      m_subsystems;
+
+  std::unique_ptr<clang_utils::TypeSystemClangHolder> m_holder;
+  lldb::DebuggerSP m_debugger_sp;
+  lldb::TargetSP m_target_sp;
+  lldb::PlatformSP m_platform_sp;
+  lldb::ListenerSP m_listener_sp;
+  lldb::ProcessSP m_process_sp;
+};
+
+TEST_F(ValueObjectMockProcessTest, Enum) {
+  // This is not a bitfield-like enum, so values are printed as decimal by
+  // default. Also we only show the enumerator name if the value is an
+  // exact match.
+  TestDumpValueObject(
+      MakeEnumType({{"test_2", 2}, {"test_3", 3}}),
+      {{0, {}, "(TestEnum) test_var = 0\n"},
+       {1, {}, "(TestEnum) test_var = 1\n"},
+       {2, {}, "(TestEnum) test_var = test_2\n"},
+       {3, {}, "(TestEnum) test_var = test_3\n"},
+       {4, {}, "(TestEnum) test_var = 4\n"},
+       {5, {}, "(TestEnum) test_var = 5\n"},
+       {1, DumpValueObjectOptions().SetHideRootName(true), "(TestEnum) 1\n"},
+       {1, DumpValueObjectOptions().SetHideRootType(true), "test_var = 1\n"},
+       {1, DumpValueObjectOptions().SetHideRootName(true).SetHideRootType(true),
+        "1\n"},
+       {1, DumpValueObjectOptions().SetHideName(true), "(TestEnum) 1\n"},
+       {1, DumpValueObjectOptions().SetHideValue(true),
+        "(TestEnum) test_var =\n"},
+       {1, DumpValueObjectOptions().SetHideName(true).SetHideValue(true),
+        "(TestEnum) \n"}});
+}
+
+TEST_F(ValueObjectMockProcessTest, BitFieldLikeEnum) {
+  // These enumerators set individual bits in the value, as if it were a flag
+  // set. lldb treats this as a "bitfield like enum". This means we show values
+  // as hex, a value of 0 shows nothing, and values with no exact enumerator are
+  // shown as combinations of the other values.
+  TestDumpValueObject(
+      MakeEnumType({{"test_2", 2}, {"test_4", 4}}),
+      {
+          {0, {}, "(TestEnum) test_var =\n"},
+          {1, {}, "(TestEnum) test_var = 0x1\n"},
+          {2, {}, "(TestEnum) test_var = test_2\n"},
+          {4, {}, "(TestEnum) test_var = test_4\n"},
+          {6, {}, "(TestEnum) test_var = test_2 | test_4\n"},
+          {7, {}, "(TestEnum) test_var = test_2 | test_4 | 0x1\n"},
+          {8, {}, "(TestEnum) test_var = 0x8\n"},
+          {1, DumpValueObjectOptions().SetHideRootName(true),
+           "(TestEnum) 0x1\n"},
+          {1, DumpValueObjectOptions().SetHideRootType(true),
+           "test_var = 0x1\n"},
+          {1,
+           DumpValueObjectOptions().SetHideRootName(true).SetHideRootType(true),
+           "0x1\n"},
+          {1, DumpValueObjectOptions().SetHideName(true), "(TestEnum) 0x1\n"},
+          {1, DumpValueObjectOptions().SetHideValue(true),
+           "(TestEnum) test_var =\n"},
+          {1, DumpValueObjectOptions().SetHideName(true).SetHideValue(true),
+           "(TestEnum) \n"},
+      });
+}