src/third_party/v8/test/cctest/test-debug-helper.cc - cobalt - Git at Google

 // Copyright 2018 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.

 #include "src/api/api-inl.h"
 #include "src/execution/frames-inl.h"
 #include "src/flags/flags.h"
 #include "src/heap/read-only-spaces.h"
 #include "src/heap/spaces.h"
 #include "test/cctest/cctest.h"
 #include "tools/debug_helper/debug-helper.h"

 namespace v8 {
 namespace internal {

 namespace {

 namespace d = v8::debug_helper;

 uintptr_t memory_fail_start = 0;
 uintptr_t memory_fail_end = 0;

 class MemoryFailureRegion {
  public:
   MemoryFailureRegion(uintptr_t start, uintptr_t end) {
     memory_fail_start = start;
     memory_fail_end = end;
   }
   ~MemoryFailureRegion() {
     memory_fail_start = 0;
     memory_fail_end = 0;
   }
 };

 // Implement the memory-reading callback. This one just fetches memory from the
 // current process, but a real implementation for a debugging extension would
 // fetch memory from the debuggee process or crash dump.
 d::MemoryAccessResult ReadMemory(uintptr_t address, void* destination,
                                  size_t byte_count) {
   if (address >= memory_fail_start && address <= memory_fail_end) {
     // Simulate failure to read debuggee memory.
     return d::MemoryAccessResult::kAddressValidButInaccessible;
   }
   memcpy(destination, reinterpret_cast<void*>(address), byte_count);
   return d::MemoryAccessResult::kOk;
 }

 void CheckPropBase(const d::PropertyBase& property, const char* expected_type,
                    const char* expected_name) {
   CHECK(property.type == std::string("v8::internal::TaggedValue") ||
         property.type == std::string(expected_type));
   CHECK(property.decompressed_type == std::string(expected_type));
   CHECK(property.name == std::string(expected_name));
 }

 void CheckProp(const d::ObjectProperty& property, const char* expected_type,
                const char* expected_name,
                d::PropertyKind expected_kind = d::PropertyKind::kSingle,
                size_t expected_num_values = 1) {
   CheckPropBase(property, expected_type, expected_name);
   CHECK_EQ(property.num_values, expected_num_values);
   CHECK(property.kind == expected_kind);
 }

 template <typename TValue>
 void CheckProp(const d::ObjectProperty& property, const char* expected_type,
                const char* expected_name, TValue expected_value) {
   CheckProp(property, expected_type, expected_name);
   CHECK(*reinterpret_cast<TValue*>(property.address) == expected_value);
 }

 bool StartsWith(const std::string& full_string, const std::string& prefix) {
   return full_string.substr(0, prefix.size()) == prefix;
 }

 bool Contains(const std::string& full_string, const std::string& substr) {
   return full_string.find(substr) != std::string::npos;
 }

 void CheckStructProp(const d::StructProperty& property,
                      const char* expected_type, const char* expected_name,
                      size_t expected_offset, uint8_t expected_num_bits = 0,
                      uint8_t expected_shift_bits = 0) {
   CheckPropBase(property, expected_type, expected_name);
   CHECK_EQ(property.offset, expected_offset);
   CHECK_EQ(property.num_bits, expected_num_bits);
   CHECK_EQ(property.shift_bits, expected_shift_bits);
 }

 const d::ObjectProperty& FindProp(const d::ObjectPropertiesResult& props,
                                   std::string name) {
   for (size_t i = 0; i < props.num_properties; ++i) {
     if (name == props.properties[i]->name) {
       return *props.properties[i];
     }
   }
   CHECK_WITH_MSG(false, ("property '" + name + "' not found").c_str());
   UNREACHABLE();
 }

 template <typename TValue>
 TValue ReadProp(const d::ObjectPropertiesResult& props, std::string name) {
   const d::ObjectProperty& prop = FindProp(props, name);
   return *reinterpret_cast<TValue*>(prop.address);
 }

 // A simple implementation of ExternalStringResource that lets us control the
 // result of IsCacheable().
 class StringResource : public v8::String::ExternalStringResource {
  public:
   explicit StringResource(bool cacheable) : cacheable_(cacheable) {}
   const uint16_t* data() const override {
     return reinterpret_cast<const uint16_t*>(u"abcde");
   }
   size_t length() const override { return 5; }
   bool IsCacheable() const override { return cacheable_; }

  private:
   bool cacheable_;
 };

 }  // namespace

 TEST(GetObjectProperties) {
   CcTest::InitializeVM();
   v8::Isolate* isolate = CcTest::isolate();
   i::Isolate* i_isolate = reinterpret_cast<i::Isolate*>(isolate);
   v8::HandleScope scope(isolate);
   LocalContext context;
   // Claim we don't know anything about the heap layout.
   d::HeapAddresses heap_addresses{0, 0, 0, 0};

   v8::Local<v8::Value> v = CompileRun("42");
   Handle<Object> o = v8::Utils::OpenHandle(*v);
   d::ObjectPropertiesResultPtr props =
       d::GetObjectProperties(o->ptr(), &ReadMemory, heap_addresses);
   CHECK(props->type_check_result == d::TypeCheckResult::kSmi);
   CHECK(props->brief == std::string("42 (0x2a)"));
   CHECK(props->type == std::string("v8::internal::Smi"));
   CHECK_EQ(props->num_properties, 0);

   v = CompileRun("[\"a\", \"bc\"]");
   o = v8::Utils::OpenHandle(*v);
   props = d::GetObjectProperties(o->ptr(), &ReadMemory, heap_addresses);
   CHECK(props->type_check_result == d::TypeCheckResult::kUsedMap);
   CHECK(props->type == std::string("v8::internal::JSArray"));
   CHECK_EQ(props->num_properties, 4);
   CheckProp(*props->properties[0], "v8::internal::Map", "map");
   CheckProp(*props->properties[1], "v8::internal::Object",
             "properties_or_hash");
   CheckProp(*props->properties[2], "v8::internal::FixedArrayBase", "elements");
   CheckProp(*props->properties[3], "v8::internal::Object", "length",
             static_cast<i::Tagged_t>(IntToSmi(2)));

   // We need to supply some valid address for decompression before reading the
   // elements from the JSArray.
   heap_addresses.any_heap_pointer = o->ptr();

   i::Tagged_t properties_or_hash =
       *reinterpret_cast<i::Tagged_t*>(props->properties[1]->address);
   i::Tagged_t elements =
       *reinterpret_cast<i::Tagged_t*>(props->properties[2]->address);

   // The properties_or_hash_code field should be an empty fixed array. Since
   // that is at a known offset, we should be able to detect it even without
   // any ability to read memory.
   {
     MemoryFailureRegion failure(0, UINTPTR_MAX);
     props =
         d::GetObjectProperties(properties_or_hash, &ReadMemory, heap_addresses);
     CHECK(props->type_check_result ==
           d::TypeCheckResult::kObjectPointerValidButInaccessible);
     CHECK(props->type == std::string("v8::internal::HeapObject"));
     CHECK_EQ(props->num_properties, 1);
     CheckProp(*props->properties[0], "v8::internal::Map", "map");
     // "maybe" prefix indicates that GetObjectProperties recognized the offset
     // within the page as matching a known object, but didn't know whether the
     // object is on the right page. This response can only happen in builds
     // without pointer compression, because otherwise heap addresses would be at
     // deterministic locations within the heap reservation.
     CHECK(COMPRESS_POINTERS_BOOL
               ? StartsWith(props->brief, "EmptyFixedArray")
               : Contains(props->brief, "maybe EmptyFixedArray"));

     // Provide a heap first page so the API can be more sure.
     heap_addresses.read_only_space_first_page =
         i_isolate->heap()->read_only_space()->FirstPageAddress();
     props =
         d::GetObjectProperties(properties_or_hash, &ReadMemory, heap_addresses);
     CHECK(props->type_check_result ==
           d::TypeCheckResult::kObjectPointerValidButInaccessible);
     CHECK(props->type == std::string("v8::internal::HeapObject"));
     CHECK_EQ(props->num_properties, 1);
     CheckProp(*props->properties[0], "v8::internal::Map", "map");
     CHECK(StartsWith(props->brief, "EmptyFixedArray"));
   }

   props = d::GetObjectProperties(elements, &ReadMemory, heap_addresses);
   CHECK(props->type_check_result == d::TypeCheckResult::kUsedMap);
   CHECK(props->type == std::string("v8::internal::FixedArray"));
   CHECK_EQ(props->num_properties, 3);
   CheckProp(*props->properties[0], "v8::internal::Map", "map");
   CheckProp(*props->properties[1], "v8::internal::Object", "length",
             static_cast<i::Tagged_t>(IntToSmi(2)));
   CheckProp(*props->properties[2], "v8::internal::Object", "objects",
             d::PropertyKind::kArrayOfKnownSize, 2);

   // Get the second string value from the FixedArray.
   i::Tagged_t second_string_address =
       reinterpret_cast<i::Tagged_t*>(props->properties[2]->address)[1];
   props = d::GetObjectProperties(second_string_address, &ReadMemory,
                                  heap_addresses);
   CHECK(props->type_check_result == d::TypeCheckResult::kUsedMap);
   CHECK(props->type == std::string("v8::internal::SeqOneByteString"));
   CHECK_EQ(props->num_properties, 4);
   CheckProp(*props->properties[0], "v8::internal::Map", "map");
   CheckProp(*props->properties[1], "uint32_t", "hash_field");
   CheckProp(*props->properties[2], "int32_t", "length", 2);
   CheckProp(*props->properties[3], "char", "chars",
             d::PropertyKind::kArrayOfKnownSize, 2);
   CHECK_EQ(
       strncmp("bc",
               reinterpret_cast<const char*>(props->properties[3]->address), 2),
       0);

   // Read the second string again, using a type hint instead of the map. All of
   // its properties should match what we read last time.
   d::ObjectPropertiesResultPtr props2;
   {
     heap_addresses.read_only_space_first_page = 0;
     uintptr_t map_address =
         d::GetObjectProperties(
             *reinterpret_cast<i::Tagged_t*>(props->properties[0]->address),
             &ReadMemory, heap_addresses)
             ->properties[0]
             ->address;
     MemoryFailureRegion failure(map_address, map_address + i::Map::kSize);
     props2 = d::GetObjectProperties(second_string_address, &ReadMemory,
                                     heap_addresses, "v8::internal::String");
     if (COMPRESS_POINTERS_BOOL) {
       // The first page of each heap space can be automatically detected when
       // pointer compression is active, so we expect to use known maps instead
       // of the type hint.
       CHECK_EQ(props2->type_check_result, d::TypeCheckResult::kKnownMapPointer);
       CHECK(props2->type == std::string("v8::internal::SeqOneByteString"));
       CHECK_EQ(props2->num_properties, 4);
       CheckProp(*props2->properties[3], "char", "chars",
                 d::PropertyKind::kArrayOfKnownSize, 2);
       CHECK_EQ(props2->num_guessed_types, 0);
     } else {
       CHECK_EQ(props2->type_check_result, d::TypeCheckResult::kUsedTypeHint);
       CHECK(props2->type == std::string("v8::internal::String"));
       CHECK_EQ(props2->num_properties, 3);

       // The type hint we provided was the abstract class String, but
       // GetObjectProperties should have recognized that the Map pointer looked
       // like the right value for a SeqOneByteString.
       CHECK_EQ(props2->num_guessed_types, 1);
       CHECK(std::string(props2->guessed_types[0]) ==
             std::string("v8::internal::SeqOneByteString"));
     }
     CheckProp(*props2->properties[0], "v8::internal::Map", "map",
               *reinterpret_cast<i::Tagged_t*>(props->properties[0]->address));
     CheckProp(*props2->properties[1], "uint32_t", "hash_field",
               *reinterpret_cast<int32_t*>(props->properties[1]->address));
     CheckProp(*props2->properties[2], "int32_t", "length", 2);
   }

   // Try a weak reference.
   props2 = d::GetObjectProperties(second_string_address | kWeakHeapObjectMask,
                                   &ReadMemory, heap_addresses);
   std::string weak_ref_prefix = "weak ref to ";
   CHECK(weak_ref_prefix + props->brief == props2->brief);
   CHECK(props2->type_check_result == d::TypeCheckResult::kUsedMap);
   CHECK(props2->type == std::string("v8::internal::SeqOneByteString"));
   CHECK_EQ(props2->num_properties, 4);
   CheckProp(*props2->properties[0], "v8::internal::Map", "map",
             *reinterpret_cast<i::Tagged_t*>(props->properties[0]->address));
   CheckProp(*props2->properties[1], "uint32_t", "hash_field",
             *reinterpret_cast<i::Tagged_t*>(props->properties[1]->address));
   CheckProp(*props2->properties[2], "int32_t", "length", 2);

   // Build a complicated string (multi-level cons with slices inside) to test
   // string printing.
   v = CompileRun(R"(
     const alphabet = "abcdefghijklmnopqrstuvwxyz";
     alphabet.substr(3,20) + alphabet.toUpperCase().substr(5,15) + "7")");
   o = v8::Utils::OpenHandle(*v);
   props = d::GetObjectProperties(o->ptr(), &ReadMemory, heap_addresses);
   CHECK(Contains(props->brief, "\"defghijklmnopqrstuvwFGHIJKLMNOPQRST7\""));

   // Cause a failure when reading the "second" pointer within the top-level
   // ConsString.
   {
     CheckProp(*props->properties[4], "v8::internal::String", "second");
     uintptr_t second_address = props->properties[4]->address;
     MemoryFailureRegion failure(second_address, second_address + 4);
     props = d::GetObjectProperties(o->ptr(), &ReadMemory, heap_addresses);
     CHECK(Contains(props->brief, "\"defghijklmnopqrstuvwFGHIJKLMNOPQRST...\""));
   }

   // Build a very long string.
   v = CompileRun("'a'.repeat(1000)");
   o = v8::Utils::OpenHandle(*v);
   props = d::GetObjectProperties(o->ptr(), &ReadMemory, heap_addresses);
   CHECK(Contains(props->brief, "\"" + std::string(80, 'a') + "...\""));

   // GetObjectProperties can read cacheable external strings.
   auto external_string =
       v8::String::NewExternalTwoByte(isolate, new StringResource(true));
   o = v8::Utils::OpenHandle(*external_string.ToLocalChecked());
   props = d::GetObjectProperties(o->ptr(), &ReadMemory, heap_addresses);
   CHECK(Contains(props->brief, "\"abcde\""));
   // GetObjectProperties cannot read uncacheable external strings.
   external_string =
       v8::String::NewExternalTwoByte(isolate, new StringResource(false));
   o = v8::Utils::OpenHandle(*external_string.ToLocalChecked());
   props = d::GetObjectProperties(o->ptr(), &ReadMemory, heap_addresses);
   CHECK_EQ(std::string(props->brief).find("\""), std::string::npos);

   // Build a basic JS object and get its properties.
   v = CompileRun("({a: 1, b: 2})");
   o = v8::Utils::OpenHandle(*v);
   props = d::GetObjectProperties(o->ptr(), &ReadMemory, heap_addresses);

   // Objects constructed from literals get their properties placed inline, so
   // the GetObjectProperties response should include an array.
   const d::ObjectProperty& prop = FindProp(*props, "in-object properties");
   CheckProp(prop, "v8::internal::Object", "in-object properties",
             d::PropertyKind::kArrayOfKnownSize, 2);
   // The second item in that array is the SMI value 2 from the object literal.
   props2 =
       d::GetObjectProperties(reinterpret_cast<i::Tagged_t*>(prop.address)[1],
                              &ReadMemory, heap_addresses);
   CHECK(props2->brief == std::string("2 (0x2)"));

   // Verify the result for a heap object field which is itself a struct: the
   // "descriptors" field on a DescriptorArray.
   // Start by getting the object's map and the map's descriptor array.
   props = d::GetObjectProperties(ReadProp<i::Tagged_t>(*props, "map"),
                                  &ReadMemory, heap_addresses);
   props = d::GetObjectProperties(
       ReadProp<i::Tagged_t>(*props, "instance_descriptors"), &ReadMemory,
       heap_addresses);
   // It should have at least two descriptors (possibly plus slack).
   CheckProp(*props->properties[1], "uint16_t", "number_of_all_descriptors");
   uint16_t number_of_all_descriptors =
       *reinterpret_cast<uint16_t*>(props->properties[1]->address);
   CHECK_GE(number_of_all_descriptors, 2);
   // The "descriptors" property should describe the struct layout for each
   // element in the array.
   const d::ObjectProperty& descriptors = *props->properties[6];
   // No C++ type is reported directly because there may not be an actual C++
   // struct with this layout, hence the empty string in this check.
   CheckProp(descriptors, /*type=*/"", "descriptors",
             d::PropertyKind::kArrayOfKnownSize, number_of_all_descriptors);
   CHECK_EQ(descriptors.size, 3 * i::kTaggedSize);
   CHECK_EQ(descriptors.num_struct_fields, 3);
   CheckStructProp(*descriptors.struct_fields[0],
                   "v8::internal::PrimitiveHeapObject", "key",
                   0 * i::kTaggedSize);
   CheckStructProp(*descriptors.struct_fields[1], "v8::internal::Object",
                   "details", 1 * i::kTaggedSize);
   CheckStructProp(*descriptors.struct_fields[2], "v8::internal::Object",
                   "value", 2 * i::kTaggedSize);

   // Build a basic JS function and get its properties. This will allow us to
   // exercise bitfield functionality.
   v = CompileRun("(function () {})");
   o = v8::Utils::OpenHandle(*v);
   props = d::GetObjectProperties(o->ptr(), &ReadMemory, heap_addresses);
   props = d::GetObjectProperties(
       ReadProp<i::Tagged_t>(*props, "shared_function_info"), &ReadMemory,
       heap_addresses);
   const d::ObjectProperty& flags = FindProp(*props, "flags");
   CHECK_GE(flags.num_struct_fields, 3);
   CheckStructProp(*flags.struct_fields[0], "FunctionKind", "function_kind", 0,
                   5, 0);
   CheckStructProp(*flags.struct_fields[1], "bool", "is_native", 0, 1, 5);
   CheckStructProp(*flags.struct_fields[2], "bool", "is_strict", 0, 1, 6);

   // Get data about a different bitfield struct which is contained within a smi.
   Handle<i::JSFunction> function = Handle<i::JSFunction>::cast(o);
   Handle<i::SharedFunctionInfo> shared(function->shared(), i_isolate);
   Handle<i::DebugInfo> debug_info =
       i_isolate->debug()->GetOrCreateDebugInfo(shared);
   props =
       d::GetObjectProperties(debug_info->ptr(), &ReadMemory, heap_addresses);
   const d::ObjectProperty& debug_flags = FindProp(*props, "flags");
   CHECK_GE(debug_flags.num_struct_fields, 5);
   CheckStructProp(*debug_flags.struct_fields[0], "bool", "has_break_info", 0, 1,
                   i::kSmiTagSize + i::kSmiShiftSize);
   CheckStructProp(*debug_flags.struct_fields[4], "bool", "can_break_at_entry",
                   0, 1, i::kSmiTagSize + i::kSmiShiftSize + 4);
 }

 TEST(ListObjectClasses) {
   CcTest::InitializeVM();

   // The ListObjectClasses result will change as classes are added, removed, or
   // renamed. Just check that a few expected classes are included in the list,
   // and that there are no duplicates.
   const d::ClassList* class_list = d::ListObjectClasses();
   std::unordered_set<std::string> class_set;
   for (size_t i = 0; i < class_list->num_class_names; ++i) {
     CHECK_WITH_MSG(class_set.insert(class_list->class_names[i]).second,
                    "there should be no duplicate entries");
   }
   CHECK_NE(class_set.find("v8::internal::HeapObject"), class_set.end());
   CHECK_NE(class_set.find("v8::internal::String"), class_set.end());
   CHECK_NE(class_set.find("v8::internal::JSRegExp"), class_set.end());
 }

 static void FrameIterationCheck(
     v8::Local<v8::String> name,
     const v8::PropertyCallbackInfo<v8::Value>& info) {
   i::StackFrameIterator iter(reinterpret_cast<i::Isolate*>(info.GetIsolate()));
   for (int i = 0; !iter.done(); i++) {
     i::StackFrame* frame = iter.frame();
     CHECK(i != 0 || (frame->type() == i::StackFrame::EXIT));
     d::StackFrameResultPtr props = d::GetStackFrame(frame->fp(), &ReadMemory);
     if (frame->is_java_script()) {
       JavaScriptFrame* js_frame = JavaScriptFrame::cast(frame);
       CHECK_EQ(props->num_properties, 1);
       CheckProp(*props->properties[0], "v8::internal::JSFunction",
                 "currently_executing_jsfunction", js_frame->function().ptr());
     } else {
       CHECK_EQ(props->num_properties, 0);
     }
     iter.Advance();
   }
 }

 THREADED_TEST(GetFrameStack) {
   LocalContext env;
   v8::Isolate* isolate = env->GetIsolate();
   v8::HandleScope scope(isolate);
   v8::Local<v8::ObjectTemplate> obj = v8::ObjectTemplate::New(isolate);
   obj->SetAccessor(v8_str("xxx"), FrameIterationCheck);
   CHECK(env->Global()
             ->Set(env.local(), v8_str("obj"),
                   obj->NewInstance(env.local()).ToLocalChecked())
             .FromJust());
   v8::Script::Compile(env.local(), v8_str("function foo() {"
                                           "  return obj.xxx;"
                                           "}"
                                           "foo();"))
       .ToLocalChecked()
       ->Run(env.local())
       .ToLocalChecked();
 }

 }  // namespace internal
 }  // namespace v8
	// Copyright 2018 the V8 project authors. All rights reserved.
	// Use of this source code is governed by a BSD-style license that can be
	// found in the LICENSE file.

	#include "src/api/api-inl.h"
	#include "src/execution/frames-inl.h"
	#include "src/flags/flags.h"
	#include "src/heap/read-only-spaces.h"
	#include "src/heap/spaces.h"
	#include "test/cctest/cctest.h"
	#include "tools/debug_helper/debug-helper.h"

	namespace v8 {
	namespace internal {

	namespace {

	namespace d = v8::debug_helper;

	uintptr_t memory_fail_start = 0;
	uintptr_t memory_fail_end = 0;

	class MemoryFailureRegion {
	public:
	MemoryFailureRegion(uintptr_t start, uintptr_t end) {
	memory_fail_start = start;
	memory_fail_end = end;
	}
	~MemoryFailureRegion() {
	memory_fail_start = 0;
	memory_fail_end = 0;
	}
	};

	// Implement the memory-reading callback. This one just fetches memory from the
	// current process, but a real implementation for a debugging extension would
	// fetch memory from the debuggee process or crash dump.
	d::MemoryAccessResult ReadMemory(uintptr_t address, void* destination,
	size_t byte_count) {
	if (address >= memory_fail_start && address <= memory_fail_end) {
	// Simulate failure to read debuggee memory.
	return d::MemoryAccessResult::kAddressValidButInaccessible;
	}
	memcpy(destination, reinterpret_cast<void*>(address), byte_count);
	return d::MemoryAccessResult::kOk;
	}

	void CheckPropBase(const d::PropertyBase& property, const char* expected_type,
	const char* expected_name) {
	CHECK(property.type == std::string("v8::internal::TaggedValue") \|\|
	property.type == std::string(expected_type));
	CHECK(property.decompressed_type == std::string(expected_type));
	CHECK(property.name == std::string(expected_name));
	}

	void CheckProp(const d::ObjectProperty& property, const char* expected_type,
	const char* expected_name,
	d::PropertyKind expected_kind = d::PropertyKind::kSingle,
	size_t expected_num_values = 1) {
	CheckPropBase(property, expected_type, expected_name);
	CHECK_EQ(property.num_values, expected_num_values);
	CHECK(property.kind == expected_kind);
	}

	template <typename TValue>
	void CheckProp(const d::ObjectProperty& property, const char* expected_type,
	const char* expected_name, TValue expected_value) {
	CheckProp(property, expected_type, expected_name);
	CHECK(reinterpret_cast<TValue>(property.address) == expected_value);
	}

	bool StartsWith(const std::string& full_string, const std::string& prefix) {
	return full_string.substr(0, prefix.size()) == prefix;
	}

	bool Contains(const std::string& full_string, const std::string& substr) {
	return full_string.find(substr) != std::string::npos;
	}

	void CheckStructProp(const d::StructProperty& property,
	const char* expected_type, const char* expected_name,
	size_t expected_offset, uint8_t expected_num_bits = 0,
	uint8_t expected_shift_bits = 0) {
	CheckPropBase(property, expected_type, expected_name);
	CHECK_EQ(property.offset, expected_offset);
	CHECK_EQ(property.num_bits, expected_num_bits);
	CHECK_EQ(property.shift_bits, expected_shift_bits);
	}

	const d::ObjectProperty& FindProp(const d::ObjectPropertiesResult& props,
	std::string name) {
	for (size_t i = 0; i < props.num_properties; ++i) {
	if (name == props.properties[i]->name) {
	return *props.properties[i];
	}
	}
	CHECK_WITH_MSG(false, ("property '" + name + "' not found").c_str());
	UNREACHABLE();
	}

	template <typename TValue>
	TValue ReadProp(const d::ObjectPropertiesResult& props, std::string name) {
	const d::ObjectProperty& prop = FindProp(props, name);
	return reinterpret_cast<TValue>(prop.address);
	}

	// A simple implementation of ExternalStringResource that lets us control the
	// result of IsCacheable().
	class StringResource : public v8::String::ExternalStringResource {
	public:
	explicit StringResource(bool cacheable) : cacheable_(cacheable) {}
	const uint16_t* data() const override {
	return reinterpret_cast<const uint16_t*>(u"abcde");
	}
	size_t length() const override { return 5; }
	bool IsCacheable() const override { return cacheable_; }

	private:
	bool cacheable_;
	};

	} // namespace

	TEST(GetObjectProperties) {
	CcTest::InitializeVM();
	v8::Isolate* isolate = CcTest::isolate();
	i::Isolate* i_isolate = reinterpret_cast<i::Isolate*>(isolate);
	v8::HandleScope scope(isolate);
	LocalContext context;
	// Claim we don't know anything about the heap layout.
	d::HeapAddresses heap_addresses{0, 0, 0, 0};

	v8::Local<v8::Value> v = CompileRun("42");
	Handle<Object> o = v8::Utils::OpenHandle(*v);
	d::ObjectPropertiesResultPtr props =
	d::GetObjectProperties(o->ptr(), &ReadMemory, heap_addresses);
	CHECK(props->type_check_result == d::TypeCheckResult::kSmi);
	CHECK(props->brief == std::string("42 (0x2a)"));
	CHECK(props->type == std::string("v8::internal::Smi"));
	CHECK_EQ(props->num_properties, 0);

	v = CompileRun("[\"a\", \"bc\"]");
	o = v8::Utils::OpenHandle(*v);
	props = d::GetObjectProperties(o->ptr(), &ReadMemory, heap_addresses);
	CHECK(props->type_check_result == d::TypeCheckResult::kUsedMap);
	CHECK(props->type == std::string("v8::internal::JSArray"));
	CHECK_EQ(props->num_properties, 4);
	CheckProp(*props->properties[0], "v8::internal::Map", "map");
	CheckProp(*props->properties[1], "v8::internal::Object",
	"properties_or_hash");
	CheckProp(*props->properties[2], "v8::internal::FixedArrayBase", "elements");
	CheckProp(*props->properties[3], "v8::internal::Object", "length",
	static_cast<i::Tagged_t>(IntToSmi(2)));

	// We need to supply some valid address for decompression before reading the
	// elements from the JSArray.
	heap_addresses.any_heap_pointer = o->ptr();

	i::Tagged_t properties_or_hash =
	reinterpret_cast<i::Tagged_t>(props->properties[1]->address);
	i::Tagged_t elements =
	reinterpret_cast<i::Tagged_t>(props->properties[2]->address);

	// The properties_or_hash_code field should be an empty fixed array. Since
	// that is at a known offset, we should be able to detect it even without
	// any ability to read memory.
	{
	MemoryFailureRegion failure(0, UINTPTR_MAX);
	props =
	d::GetObjectProperties(properties_or_hash, &ReadMemory, heap_addresses);
	CHECK(props->type_check_result ==
	d::TypeCheckResult::kObjectPointerValidButInaccessible);
	CHECK(props->type == std::string("v8::internal::HeapObject"));
	CHECK_EQ(props->num_properties, 1);
	CheckProp(*props->properties[0], "v8::internal::Map", "map");
	// "maybe" prefix indicates that GetObjectProperties recognized the offset
	// within the page as matching a known object, but didn't know whether the
	// object is on the right page. This response can only happen in builds
	// without pointer compression, because otherwise heap addresses would be at
	// deterministic locations within the heap reservation.
	CHECK(COMPRESS_POINTERS_BOOL
	? StartsWith(props->brief, "EmptyFixedArray")
	: Contains(props->brief, "maybe EmptyFixedArray"));

	// Provide a heap first page so the API can be more sure.
	heap_addresses.read_only_space_first_page =
	i_isolate->heap()->read_only_space()->FirstPageAddress();
	props =
	d::GetObjectProperties(properties_or_hash, &ReadMemory, heap_addresses);
	CHECK(props->type_check_result ==
	d::TypeCheckResult::kObjectPointerValidButInaccessible);
	CHECK(props->type == std::string("v8::internal::HeapObject"));
	CHECK_EQ(props->num_properties, 1);
	CheckProp(*props->properties[0], "v8::internal::Map", "map");
	CHECK(StartsWith(props->brief, "EmptyFixedArray"));
	}

	props = d::GetObjectProperties(elements, &ReadMemory, heap_addresses);
	CHECK(props->type_check_result == d::TypeCheckResult::kUsedMap);
	CHECK(props->type == std::string("v8::internal::FixedArray"));
	CHECK_EQ(props->num_properties, 3);
	CheckProp(*props->properties[0], "v8::internal::Map", "map");
	CheckProp(*props->properties[1], "v8::internal::Object", "length",
	static_cast<i::Tagged_t>(IntToSmi(2)));
	CheckProp(*props->properties[2], "v8::internal::Object", "objects",
	d::PropertyKind::kArrayOfKnownSize, 2);

	// Get the second string value from the FixedArray.
	i::Tagged_t second_string_address =
	reinterpret_cast<i::Tagged_t*>(props->properties[2]->address)[1];
	props = d::GetObjectProperties(second_string_address, &ReadMemory,
	heap_addresses);
	CHECK(props->type_check_result == d::TypeCheckResult::kUsedMap);
	CHECK(props->type == std::string("v8::internal::SeqOneByteString"));
	CHECK_EQ(props->num_properties, 4);
	CheckProp(*props->properties[0], "v8::internal::Map", "map");
	CheckProp(*props->properties[1], "uint32_t", "hash_field");
	CheckProp(*props->properties[2], "int32_t", "length", 2);
	CheckProp(*props->properties[3], "char", "chars",
	d::PropertyKind::kArrayOfKnownSize, 2);
	CHECK_EQ(
	strncmp("bc",
	reinterpret_cast<const char*>(props->properties[3]->address), 2),
	0);

	// Read the second string again, using a type hint instead of the map. All of
	// its properties should match what we read last time.
	d::ObjectPropertiesResultPtr props2;
	{
	heap_addresses.read_only_space_first_page = 0;
	uintptr_t map_address =
	d::GetObjectProperties(
	reinterpret_cast<i::Tagged_t>(props->properties[0]->address),
	&ReadMemory, heap_addresses)
	->properties[0]
	->address;
	MemoryFailureRegion failure(map_address, map_address + i::Map::kSize);
	props2 = d::GetObjectProperties(second_string_address, &ReadMemory,
	heap_addresses, "v8::internal::String");
	if (COMPRESS_POINTERS_BOOL) {
	// The first page of each heap space can be automatically detected when
	// pointer compression is active, so we expect to use known maps instead
	// of the type hint.
	CHECK_EQ(props2->type_check_result, d::TypeCheckResult::kKnownMapPointer);
	CHECK(props2->type == std::string("v8::internal::SeqOneByteString"));
	CHECK_EQ(props2->num_properties, 4);
	CheckProp(*props2->properties[3], "char", "chars",
	d::PropertyKind::kArrayOfKnownSize, 2);
	CHECK_EQ(props2->num_guessed_types, 0);
	} else {
	CHECK_EQ(props2->type_check_result, d::TypeCheckResult::kUsedTypeHint);
	CHECK(props2->type == std::string("v8::internal::String"));
	CHECK_EQ(props2->num_properties, 3);

	// The type hint we provided was the abstract class String, but
	// GetObjectProperties should have recognized that the Map pointer looked
	// like the right value for a SeqOneByteString.
	CHECK_EQ(props2->num_guessed_types, 1);
	CHECK(std::string(props2->guessed_types[0]) ==
	std::string("v8::internal::SeqOneByteString"));
	}
	CheckProp(*props2->properties[0], "v8::internal::Map", "map",
	reinterpret_cast<i::Tagged_t>(props->properties[0]->address));
	CheckProp(*props2->properties[1], "uint32_t", "hash_field",
	reinterpret_cast<int32_t>(props->properties[1]->address));
	CheckProp(*props2->properties[2], "int32_t", "length", 2);
	}

	// Try a weak reference.
	props2 = d::GetObjectProperties(second_string_address \| kWeakHeapObjectMask,
	&ReadMemory, heap_addresses);
	std::string weak_ref_prefix = "weak ref to ";
	CHECK(weak_ref_prefix + props->brief == props2->brief);
	CHECK(props2->type_check_result == d::TypeCheckResult::kUsedMap);
	CHECK(props2->type == std::string("v8::internal::SeqOneByteString"));
	CHECK_EQ(props2->num_properties, 4);
	CheckProp(*props2->properties[0], "v8::internal::Map", "map",
	reinterpret_cast<i::Tagged_t>(props->properties[0]->address));
	CheckProp(*props2->properties[1], "uint32_t", "hash_field",
	reinterpret_cast<i::Tagged_t>(props->properties[1]->address));
	CheckProp(*props2->properties[2], "int32_t", "length", 2);

	// Build a complicated string (multi-level cons with slices inside) to test
	// string printing.
	v = CompileRun(R"(
	const alphabet = "abcdefghijklmnopqrstuvwxyz";
	alphabet.substr(3,20) + alphabet.toUpperCase().substr(5,15) + "7")");
	o = v8::Utils::OpenHandle(*v);
	props = d::GetObjectProperties(o->ptr(), &ReadMemory, heap_addresses);
	CHECK(Contains(props->brief, "\"defghijklmnopqrstuvwFGHIJKLMNOPQRST7\""));

	// Cause a failure when reading the "second" pointer within the top-level
	// ConsString.
	{
	CheckProp(*props->properties[4], "v8::internal::String", "second");
	uintptr_t second_address = props->properties[4]->address;
	MemoryFailureRegion failure(second_address, second_address + 4);
	props = d::GetObjectProperties(o->ptr(), &ReadMemory, heap_addresses);
	CHECK(Contains(props->brief, "\"defghijklmnopqrstuvwFGHIJKLMNOPQRST...\""));
	}

	// Build a very long string.
	v = CompileRun("'a'.repeat(1000)");
	o = v8::Utils::OpenHandle(*v);
	props = d::GetObjectProperties(o->ptr(), &ReadMemory, heap_addresses);
	CHECK(Contains(props->brief, "\"" + std::string(80, 'a') + "...\""));

	// GetObjectProperties can read cacheable external strings.
	auto external_string =
	v8::String::NewExternalTwoByte(isolate, new StringResource(true));
	o = v8::Utils::OpenHandle(*external_string.ToLocalChecked());
	props = d::GetObjectProperties(o->ptr(), &ReadMemory, heap_addresses);
	CHECK(Contains(props->brief, "\"abcde\""));
	// GetObjectProperties cannot read uncacheable external strings.
	external_string =
	v8::String::NewExternalTwoByte(isolate, new StringResource(false));
	o = v8::Utils::OpenHandle(*external_string.ToLocalChecked());
	props = d::GetObjectProperties(o->ptr(), &ReadMemory, heap_addresses);
	CHECK_EQ(std::string(props->brief).find("\""), std::string::npos);

	// Build a basic JS object and get its properties.
	v = CompileRun("({a: 1, b: 2})");
	o = v8::Utils::OpenHandle(*v);
	props = d::GetObjectProperties(o->ptr(), &ReadMemory, heap_addresses);

	// Objects constructed from literals get their properties placed inline, so
	// the GetObjectProperties response should include an array.
	const d::ObjectProperty& prop = FindProp(*props, "in-object properties");
	CheckProp(prop, "v8::internal::Object", "in-object properties",
	d::PropertyKind::kArrayOfKnownSize, 2);
	// The second item in that array is the SMI value 2 from the object literal.
	props2 =
	d::GetObjectProperties(reinterpret_cast<i::Tagged_t*>(prop.address)[1],
	&ReadMemory, heap_addresses);
	CHECK(props2->brief == std::string("2 (0x2)"));

	// Verify the result for a heap object field which is itself a struct: the
	// "descriptors" field on a DescriptorArray.
	// Start by getting the object's map and the map's descriptor array.
	props = d::GetObjectProperties(ReadProp<i::Tagged_t>(*props, "map"),
	&ReadMemory, heap_addresses);
	props = d::GetObjectProperties(
	ReadProp<i::Tagged_t>(*props, "instance_descriptors"), &ReadMemory,
	heap_addresses);
	// It should have at least two descriptors (possibly plus slack).
	CheckProp(*props->properties[1], "uint16_t", "number_of_all_descriptors");
	uint16_t number_of_all_descriptors =
	reinterpret_cast<uint16_t>(props->properties[1]->address);
	CHECK_GE(number_of_all_descriptors, 2);
	// The "descriptors" property should describe the struct layout for each
	// element in the array.
	const d::ObjectProperty& descriptors = *props->properties[6];
	// No C++ type is reported directly because there may not be an actual C++
	// struct with this layout, hence the empty string in this check.
	CheckProp(descriptors, /type=/"", "descriptors",
	d::PropertyKind::kArrayOfKnownSize, number_of_all_descriptors);
	CHECK_EQ(descriptors.size, 3 * i::kTaggedSize);
	CHECK_EQ(descriptors.num_struct_fields, 3);
	CheckStructProp(*descriptors.struct_fields[0],
	"v8::internal::PrimitiveHeapObject", "key",
	0 * i::kTaggedSize);
	CheckStructProp(*descriptors.struct_fields[1], "v8::internal::Object",
	"details", 1 * i::kTaggedSize);
	CheckStructProp(*descriptors.struct_fields[2], "v8::internal::Object",
	"value", 2 * i::kTaggedSize);

	// Build a basic JS function and get its properties. This will allow us to
	// exercise bitfield functionality.
	v = CompileRun("(function () {})");
	o = v8::Utils::OpenHandle(*v);
	props = d::GetObjectProperties(o->ptr(), &ReadMemory, heap_addresses);
	props = d::GetObjectProperties(
	ReadProp<i::Tagged_t>(*props, "shared_function_info"), &ReadMemory,
	heap_addresses);
	const d::ObjectProperty& flags = FindProp(*props, "flags");
	CHECK_GE(flags.num_struct_fields, 3);
	CheckStructProp(*flags.struct_fields[0], "FunctionKind", "function_kind", 0,
	5, 0);
	CheckStructProp(*flags.struct_fields[1], "bool", "is_native", 0, 1, 5);
	CheckStructProp(*flags.struct_fields[2], "bool", "is_strict", 0, 1, 6);

	// Get data about a different bitfield struct which is contained within a smi.
	Handle<i::JSFunction> function = Handle<i::JSFunction>::cast(o);
	Handle<i::SharedFunctionInfo> shared(function->shared(), i_isolate);
	Handle<i::DebugInfo> debug_info =
	i_isolate->debug()->GetOrCreateDebugInfo(shared);
	props =
	d::GetObjectProperties(debug_info->ptr(), &ReadMemory, heap_addresses);
	const d::ObjectProperty& debug_flags = FindProp(*props, "flags");
	CHECK_GE(debug_flags.num_struct_fields, 5);
	CheckStructProp(*debug_flags.struct_fields[0], "bool", "has_break_info", 0, 1,
	i::kSmiTagSize + i::kSmiShiftSize);
	CheckStructProp(*debug_flags.struct_fields[4], "bool", "can_break_at_entry",
	0, 1, i::kSmiTagSize + i::kSmiShiftSize + 4);
	}

	TEST(ListObjectClasses) {
	CcTest::InitializeVM();

	// The ListObjectClasses result will change as classes are added, removed, or
	// renamed. Just check that a few expected classes are included in the list,
	// and that there are no duplicates.
	const d::ClassList* class_list = d::ListObjectClasses();
	std::unordered_set<std::string> class_set;
	for (size_t i = 0; i < class_list->num_class_names; ++i) {
	CHECK_WITH_MSG(class_set.insert(class_list->class_names[i]).second,
	"there should be no duplicate entries");
	}
	CHECK_NE(class_set.find("v8::internal::HeapObject"), class_set.end());
	CHECK_NE(class_set.find("v8::internal::String"), class_set.end());
	CHECK_NE(class_set.find("v8::internal::JSRegExp"), class_set.end());
	}

	static void FrameIterationCheck(
	v8::Local<v8::String> name,
	const v8::PropertyCallbackInfo<v8::Value>& info) {
	i::StackFrameIterator iter(reinterpret_cast<i::Isolate*>(info.GetIsolate()));
	for (int i = 0; !iter.done(); i++) {
	i::StackFrame* frame = iter.frame();
	CHECK(i != 0 \|\| (frame->type() == i::StackFrame::EXIT));
	d::StackFrameResultPtr props = d::GetStackFrame(frame->fp(), &ReadMemory);
	if (frame->is_java_script()) {
	JavaScriptFrame* js_frame = JavaScriptFrame::cast(frame);
	CHECK_EQ(props->num_properties, 1);
	CheckProp(*props->properties[0], "v8::internal::JSFunction",
	"currently_executing_jsfunction", js_frame->function().ptr());
	} else {
	CHECK_EQ(props->num_properties, 0);
	}
	iter.Advance();
	}
	}

	THREADED_TEST(GetFrameStack) {
	LocalContext env;
	v8::Isolate* isolate = env->GetIsolate();
	v8::HandleScope scope(isolate);
	v8::Local<v8::ObjectTemplate> obj = v8::ObjectTemplate::New(isolate);
	obj->SetAccessor(v8_str("xxx"), FrameIterationCheck);
	CHECK(env->Global()
	->Set(env.local(), v8_str("obj"),
	obj->NewInstance(env.local()).ToLocalChecked())
	.FromJust());
	v8::Script::Compile(env.local(), v8_str("function foo() {"
	" return obj.xxx;"
	"}"
	"foo();"))
	.ToLocalChecked()
	->Run(env.local())
	.ToLocalChecked();
	}

	} // namespace internal
	} // namespace v8