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532c116cd2db02adcb6dbf32f19d5c438fd3585b
sdk/runtime/vm/class_finalizer.cc
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Daco Harkes 532c116cd2 [vm] Implement NativeFinalizer 
This CL implements `NativeFinalizer` in the GC.

`FinalizerEntry`s are extended to track `external_size` and in which
`Heap::Space` the finalizable value is.

On attaching a native finalizer, the external size is added to the
relevant heap. When the finalizable value is promoted from new to old
space, the external size is promoted as well. And when a native
finalizer is run or is detached, the external size is removed from the
relevant heap again.

In contrast to Dart `Finalizer`s, `NativeFinalizer`s are run on isolate
shutdown.

When the `NativeFinalizer`s themselves are collected, the finalizers are
not run. Users should stick the native finalizer in a global variable to
ensure finalization. We will revisit this design when we add send and
exit support, because there is a design space to explore what to do in
that case. This current solution promises the least to users.

In this implementation native finalizers have a Dart entry to clean up
the entries from the `all_entries` field of the finalizer. We should
consider using another data structure that avoids the need for this Dart
entry. See the TODO left in the code.

Bug: https://github.com/dart-lang/sdk/issues/47777

TEST=runtime/tests/vm/dart(_2)/isolates/fast_object_copy_test.dart
TEST=runtime/vm/object_test.cc
TEST=tests/ffi(_2)/vmspecific_native_finalizer_*

Change-Id: I8f594c80c3c344ad83e1f2de10de028eb8456121
Cq-Include-Trybots: luci.dart.try:vm-kernel-reload-rollback-linux-debug-x64-try,vm-kernel-reload-linux-debug-x64-try,vm-ffi-android-debug-arm64c-try,dart-sdk-mac-arm64-try,vm-kernel-mac-release-arm64-try,pkg-mac-release-arm64-try,vm-kernel-precomp-nnbd-mac-release-arm64-try,vm-kernel-win-debug-x64c-try,vm-kernel-win-debug-x64-try,vm-kernel-precomp-win-debug-x64c-try,vm-kernel-nnbd-win-release-ia32-try,vm-ffi-android-debug-arm-try,vm-precomp-ffi-qemu-linux-release-arm-try,vm-kernel-mac-debug-x64-try,vm-kernel-nnbd-mac-debug-x64-try,vm-kernel-nnbd-linux-debug-ia32-try,benchmark-linux-try,flutter-frontend-try,pkg-linux-debug-try,vm-kernel-asan-linux-release-x64-try,vm-kernel-gcc-linux-try,vm-kernel-optcounter-threshold-linux-release-x64-try,vm-kernel-precomp-linux-debug-simarm_x64-try,vm-kernel-precomp-obfuscate-linux-release-x64-try,vm-kernel-precomp-linux-debug-x64-try,vm-kernel-precomp-linux-debug-x64c-try
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/236320
Reviewed-by: Martin Kustermann <kustermann@google.com>
Reviewed-by: Slava Egorov <vegorov@google.com>
Commit-Queue: Daco Harkes <dacoharkes@google.com>
2022-03-26 09:41:21 +00:00

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// Copyright (c) 2013, the Dart project authors. Please see the AUTHORS file
// for details. All rights reserved. Use of this source code is governed by a
// BSD-style license that can be found in the LICENSE file.
#include <memory>
#include <utility>
#include "vm/class_finalizer.h"
#include "vm/canonical_tables.h"
#include "vm/compiler/jit/compiler.h"
#include "vm/flags.h"
#include "vm/hash_table.h"
#include "vm/heap/heap.h"
#include "vm/isolate.h"
#include "vm/kernel_loader.h"
#include "vm/log.h"
#include "vm/longjump.h"
#include "vm/object_store.h"
#include "vm/program_visitor.h"
#include "vm/runtime_entry.h"
#include "vm/symbols.h"
#include "vm/timeline.h"
#include "vm/type_testing_stubs.h"
namespace dart {
DEFINE_FLAG(bool, print_classes, false, "Prints details about loaded classes.");
DEFINE_FLAG(bool, trace_class_finalization, false, "Trace class finalization.");
DEFINE_FLAG(bool, trace_type_finalization, false, "Trace type finalization.");
bool ClassFinalizer::AllClassesFinalized() {
ObjectStore* object_store = IsolateGroup::Current()->object_store();
const GrowableObjectArray& classes =
GrowableObjectArray::Handle(object_store->pending_classes());
return classes.Length() == 0;
}
#if defined(DART_PRECOMPILED_RUNTIME)
bool ClassFinalizer::ProcessPendingClasses() {
ASSERT(AllClassesFinalized());
return true;
}
#else
// Removes optimized code once we load more classes, since CHA based
// optimizations may have become invalid.
// Only methods which owner classes where subclasses can be invalid.
// TODO(srdjan): Be even more precise by recording the exact CHA optimization.
static void RemoveCHAOptimizedCode(
const Class& subclass,
const GrowableArray<intptr_t>& added_subclass_to_cids) {
ASSERT(FLAG_use_cha_deopt);
if (added_subclass_to_cids.is_empty()) {
return;
}
// Switch all functions' code to unoptimized.
const ClassTable& class_table = *IsolateGroup::Current()->class_table();
Class& cls = Class::Handle();
for (intptr_t i = 0; i < added_subclass_to_cids.length(); i++) {
intptr_t cid = added_subclass_to_cids[i];
cls = class_table.At(cid);
ASSERT(!cls.IsNull());
cls.DisableCHAOptimizedCode(subclass);
}
}
static void AddSuperType(const AbstractType& type,
GrowableArray<intptr_t>* finalized_super_classes) {
ASSERT(type.HasTypeClass());
ASSERT(!type.IsDynamicType());
if (type.IsObjectType()) {
return;
}
const Class& cls = Class::Handle(type.type_class());
ASSERT(cls.is_finalized());
const intptr_t cid = cls.id();
for (intptr_t i = 0; i < finalized_super_classes->length(); i++) {
if ((*finalized_super_classes)[i] == cid) {
// Already added.
return;
}
}
finalized_super_classes->Add(cid);
const AbstractType& super_type = AbstractType::Handle(cls.super_type());
AddSuperType(super_type, finalized_super_classes);
}
// Use array instead of set since we expect very few subclassed classes
// to occur.
static void CollectFinalizedSuperClasses(
const Class& cls_,
GrowableArray<intptr_t>* finalized_super_classes) {
Class& cls = Class::Handle(cls_.ptr());
AbstractType& super_type = Type::Handle();
super_type = cls.super_type();
if (!super_type.IsNull()) {
if (super_type.HasTypeClass()) {
cls = super_type.type_class();
if (cls.is_finalized()) {
AddSuperType(super_type, finalized_super_classes);
}
}
}
}
class InterfaceFinder {
public:
InterfaceFinder(Zone* zone,
ClassTable* class_table,
GrowableArray<intptr_t>* cids)
: class_table_(class_table),
array_handles_(zone),
class_handles_(zone),
type_handles_(zone),
cids_(cids) {}
void FindAllInterfaces(const Class& klass) {
// The class is implementing its own interface.
cids_->Add(klass.id());
ScopedHandle<Array> array(&array_handles_);
ScopedHandle<Class> interface_class(&class_handles_);
ScopedHandle<Class> current_class(&class_handles_);
ScopedHandle<AbstractType> type(&type_handles_);
*current_class = klass.ptr();
while (true) {
// We don't care about top types.
const intptr_t cid = current_class->id();
if (cid == kObjectCid || cid == kDynamicCid || cid == kVoidCid) {
break;
}
// The class is implementing its directly declared implemented interfaces.
*array = klass.interfaces();
if (!array->IsNull()) {
for (intptr_t i = 0; i < array->Length(); ++i) {
*type ^= array->At(i);
*interface_class = class_table_->At(type->type_class_id());
FindAllInterfaces(*interface_class);
}
}
// The class is implementing its super type's interfaces.
*type = current_class->super_type();
if (type->IsNull()) break;
*current_class = class_table_->At(type->type_class_id());
}
}
private:
ClassTable* class_table_;
ReusableHandleStack<Array> array_handles_;
ReusableHandleStack<Class> class_handles_;
ReusableHandleStack<AbstractType> type_handles_;
GrowableArray<intptr_t>* cids_;
};
static void CollectImmediateSuperInterfaces(const Class& cls,
GrowableArray<intptr_t>* cids) {
const Array& interfaces = Array::Handle(cls.interfaces());
Class& ifc = Class::Handle();
AbstractType& type = AbstractType::Handle();
for (intptr_t i = 0; i < interfaces.Length(); ++i) {
type ^= interfaces.At(i);
if (!type.HasTypeClass()) continue;
ifc = type.type_class();
for (intptr_t j = 0; j < cids->length(); ++j) {
if ((*cids)[j] == ifc.id()) {
// Already added.
return;
}
}
cids->Add(ifc.id());
}
}
// Processing ObjectStore::pending_classes_ occurs:
// a) when bootstrap process completes (VerifyBootstrapClasses).
// b) after the user classes are loaded (dart_api).
bool ClassFinalizer::ProcessPendingClasses() {
Thread* thread = Thread::Current();
TIMELINE_DURATION(thread, Isolate, "ProcessPendingClasses");
auto isolate_group = thread->isolate_group();
ASSERT(isolate_group != nullptr);
HANDLESCOPE(thread);
ObjectStore* object_store = isolate_group->object_store();
const Error& error = Error::Handle(thread->zone(), thread->sticky_error());
if (!error.IsNull()) {
return false;
}
if (AllClassesFinalized()) {
return true;
}
LongJumpScope jump;
if (setjmp(*jump.Set()) == 0) {
GrowableObjectArray& class_array = GrowableObjectArray::Handle();
class_array = object_store->pending_classes();
ASSERT(!class_array.IsNull());
Class& cls = Class::Handle();
#if defined(DEBUG)
for (intptr_t i = 0; i < class_array.Length(); i++) {
cls ^= class_array.At(i);
// Recognized a new class, but forgot to add @pragma('vm:entrypoint')?
ASSERT(cls.is_declaration_loaded());
}
#endif
// Finalize types in all classes.
for (intptr_t i = 0; i < class_array.Length(); i++) {
cls ^= class_array.At(i);
FinalizeTypesInClass(cls);
}
// Clear pending classes array.
class_array = GrowableObjectArray::New();
object_store->set_pending_classes(class_array);
VerifyImplicitFieldOffsets(); // Verification after an error may fail.
return true;
} else {
return false;
}
UNREACHABLE();
return true;
}
void ClassFinalizer::VerifyBootstrapClasses() {
if (FLAG_trace_class_finalization) {
OS::PrintErr("VerifyBootstrapClasses START.\n");
}
ObjectStore* object_store = IsolateGroup::Current()->object_store();
Class& cls = Class::Handle();
#if defined(DEBUG)
// Basic checking.
cls = object_store->object_class();
ASSERT_EQUAL(Instance::InstanceSize(), cls.host_instance_size());
cls = object_store->integer_implementation_class();
ASSERT_EQUAL(Integer::InstanceSize(), cls.host_instance_size());
cls = object_store->smi_class();
ASSERT_EQUAL(Smi::InstanceSize(), cls.host_instance_size());
cls = object_store->mint_class();
ASSERT_EQUAL(Mint::InstanceSize(), cls.host_instance_size());
cls = object_store->one_byte_string_class();
ASSERT_EQUAL(OneByteString::InstanceSize(), cls.host_instance_size());
cls = object_store->two_byte_string_class();
ASSERT_EQUAL(TwoByteString::InstanceSize(), cls.host_instance_size());
cls = object_store->external_one_byte_string_class();
ASSERT_EQUAL(ExternalOneByteString::InstanceSize(), cls.host_instance_size());
cls = object_store->external_two_byte_string_class();
ASSERT_EQUAL(ExternalTwoByteString::InstanceSize(), cls.host_instance_size());
cls = object_store->double_class();
ASSERT_EQUAL(Double::InstanceSize(), cls.host_instance_size());
cls = object_store->bool_class();
ASSERT_EQUAL(Bool::InstanceSize(), cls.host_instance_size());
cls = object_store->array_class();
ASSERT_EQUAL(Array::InstanceSize(), cls.host_instance_size());
cls = object_store->immutable_array_class();
ASSERT_EQUAL(ImmutableArray::InstanceSize(), cls.host_instance_size());
cls = object_store->weak_property_class();
ASSERT_EQUAL(WeakProperty::InstanceSize(), cls.host_instance_size());
cls = object_store->weak_reference_class();
ASSERT_EQUAL(WeakReference::InstanceSize(), cls.host_instance_size());
cls = object_store->finalizer_class();
ASSERT_EQUAL(Finalizer::InstanceSize(), cls.host_instance_size());
cls = object_store->finalizer_entry_class();
ASSERT_EQUAL(FinalizerEntry::InstanceSize(), cls.host_instance_size());
cls = object_store->linked_hash_map_class();
ASSERT_EQUAL(LinkedHashMap::InstanceSize(), cls.host_instance_size());
cls = object_store->immutable_linked_hash_map_class();
ASSERT_EQUAL(LinkedHashMap::InstanceSize(), cls.host_instance_size());
cls = object_store->linked_hash_set_class();
ASSERT_EQUAL(LinkedHashSet::InstanceSize(), cls.host_instance_size());
cls = object_store->immutable_linked_hash_set_class();
ASSERT_EQUAL(LinkedHashSet::InstanceSize(), cls.host_instance_size());
#endif // defined(DEBUG)
// Remember the currently pending classes.
const GrowableObjectArray& class_array =
GrowableObjectArray::Handle(object_store->pending_classes());
for (intptr_t i = 0; i < class_array.Length(); i++) {
// TODO(iposva): Add real checks.
cls ^= class_array.At(i);
if (cls.is_finalized() || cls.is_prefinalized()) {
// Pre-finalized bootstrap classes must not define any fields.
ASSERT(!cls.HasInstanceFields());
}
}
// Finalize type hierarchy for types that aren't pre-finalized
// by Object::Init().
if (!ProcessPendingClasses()) {
// TODO(srdjan): Exit like a real VM instead.
const Error& err = Error::Handle(Thread::Current()->sticky_error());
OS::PrintErr("Could not verify bootstrap classes : %s\n",
err.ToErrorCString());
OS::Exit(255);
}
if (FLAG_trace_class_finalization) {
OS::PrintErr("VerifyBootstrapClasses END.\n");
}
IsolateGroup::Current()->heap()->Verify();
}
#endif // defined(DART_PRECOMPILED_RUNTIME)
void ClassFinalizer::FinalizeTypeParameters(Zone* zone,
const Class& cls,
const FunctionType& signature,
FinalizationKind finalization,
PendingTypes* pending_types) {
if (FLAG_trace_type_finalization) {
THR_Print(
"%s type parameters of %s '%s'\n",
finalization == kFinalize ? "Finalizing" : "Canonicalizing",
!cls.IsNull() ? "class" : "signature",
String::Handle(zone, !cls.IsNull() ? cls.Name() : signature.Name())
.ToCString());
}
const TypeParameters& type_params =
TypeParameters::Handle(zone, !cls.IsNull() ? cls.type_parameters()
: signature.type_parameters());
if (!type_params.IsNull()) {
TypeArguments& type_args = TypeArguments::Handle(zone);
type_args = type_params.bounds();
type_args =
FinalizeTypeArguments(zone, type_args, finalization, pending_types);
type_params.set_bounds(type_args);
type_args = type_params.defaults();
type_args =
FinalizeTypeArguments(zone, type_args, finalization, pending_types);
type_params.set_defaults(type_args);
type_params.OptimizeFlags();
}
}
// This function reports a compilation error if the recursive 'type' T being
// finalized is a non-contractive type, i.e. if the induced type set S of P is
// not finite, where P is the instantiation of T with its own type parameters.
// The induced type set S consists of the super types of any type in S as well
// as the type arguments of any parameterized type in S.
// The Dart Language Specification does not disallow the declaration and use of
// non-contractive types (this may change). They are nevertheless disallowed
// as an implementation restriction in the VM since they cause divergence.
// A non-contractive type can be detected by looking at the queue of types
// pending finalization that are mutually recursive with the checked type.
void ClassFinalizer::CheckRecursiveType(const AbstractType& type,
PendingTypes* pending_types) {
ASSERT(!type.IsFunctionType());
ASSERT(pending_types != NULL);
Zone* zone = Thread::Current()->zone();
if (FLAG_trace_type_finalization) {
THR_Print("Checking recursive type '%s': %s\n",
String::Handle(type.Name()).ToCString(), type.ToCString());
}
const Class& type_cls = Class::Handle(zone, type.type_class());
const TypeArguments& arguments =
TypeArguments::Handle(zone, type.arguments());
// A type can only be recursive via its type arguments.
ASSERT(!arguments.IsNull());
const intptr_t num_type_args = arguments.Length();
ASSERT(num_type_args > 0);
ASSERT(num_type_args == type_cls.NumTypeArguments());
const intptr_t num_type_params = type_cls.NumTypeParameters();
const intptr_t first_type_param = num_type_args - num_type_params;
// If the type is not generic (num_type_params == 0) or if its type parameters
// are instantiated, no divergence can occur. Note that if the type parameters
// are null, i.e. if the generic type is raw, they are considered
// instantiated and no divergence can occur.
if ((num_type_params == 0) ||
arguments.IsSubvectorInstantiated(first_type_param, num_type_params)) {
return;
}
// Consider mutually recursive and uninstantiated types pending finalization
// with the same type class and report an error if they are not equal in their
// raw form, i.e. where each class type parameter is substituted with dynamic.
// This test eliminates divergent types without restricting recursive types
// typically found in the wild.
TypeArguments& pending_arguments = TypeArguments::Handle(zone);
const intptr_t num_pending_types = pending_types->length();
for (intptr_t i = num_pending_types - 1; i >= 0; i--) {
const AbstractType& pending_type = pending_types->At(i);
if (FLAG_trace_type_finalization) {
THR_Print(" Comparing with pending type '%s': %s\n",
String::Handle(pending_type.Name()).ToCString(),
pending_type.ToCString());
}
if ((pending_type.ptr() != type.ptr()) && pending_type.IsType() &&
(pending_type.type_class() == type_cls.ptr())) {
pending_arguments = pending_type.arguments();
// By using TypeEquality::kInSubtypeTest, we throw a wider net than
// using canonical or syntactical equality and may reject more
// problematic declarations.
if (!pending_arguments.IsSubvectorEquivalent(
arguments, first_type_param, num_type_params,
TypeEquality::kInSubtypeTest) &&
!pending_arguments.IsSubvectorInstantiated(first_type_param,
num_type_params)) {
const TypeArguments& instantiated_arguments = TypeArguments::Handle(
zone, arguments.InstantiateFrom(Object::null_type_arguments(),
Object::null_type_arguments(),
kNoneFree, Heap::kNew));
const TypeArguments& instantiated_pending_arguments =
TypeArguments::Handle(zone, pending_arguments.InstantiateFrom(
Object::null_type_arguments(),
Object::null_type_arguments(),
kNoneFree, Heap::kNew));
// By using TypeEquality::kInSubtypeTest, we throw a wider net than
// using canonical or syntactical equality and may reject more
// problematic declarations.
if (!instantiated_pending_arguments.IsSubvectorEquivalent(
instantiated_arguments, first_type_param, num_type_params,
TypeEquality::kInSubtypeTest)) {
const String& type_name = String::Handle(zone, type.Name());
ReportError("illegal recursive type '%s'", type_name.ToCString());
}
}
}
}
}
// Expand the type arguments of the given type and finalize its full type
// argument vector. Return the number of type arguments (0 for a raw type).
intptr_t ClassFinalizer::ExpandAndFinalizeTypeArguments(
Zone* zone,
const AbstractType& type,
PendingTypes* pending_types) {
// The type class does not need to be finalized in order to finalize the type.
// Also, the type parameters of the type class must be finalized.
Class& type_class = Class::Handle(zone, type.type_class());
type_class.EnsureDeclarationLoaded();
// The finalized type argument vector needs num_type_arguments types.
const intptr_t num_type_arguments = type_class.NumTypeArguments();
// The class has num_type_parameters type parameters.
const intptr_t num_type_parameters = type_class.NumTypeParameters();
// Initialize the type argument vector.
// A null type argument vector indicates a raw type.
TypeArguments& arguments = TypeArguments::Handle(zone, type.arguments());
ASSERT(arguments.IsNull() || (arguments.Length() == num_type_parameters));
// The full type argument vector consists of the type arguments of the
// super types of type_class, which are initialized from the parsed
// type arguments, followed by the parsed type arguments.
TypeArguments& full_arguments = TypeArguments::Handle(zone);
if (num_type_arguments > 0) {
// If no type arguments were parsed and if the super types do not prepend
// type arguments to the vector, we can leave the vector as null.
if (!arguments.IsNull() || (num_type_arguments > num_type_parameters)) {
full_arguments = TypeArguments::New(num_type_arguments);
// Copy the parsed type arguments at the correct offset in the full type
// argument vector.
const intptr_t offset = num_type_arguments - num_type_parameters;
AbstractType& type_arg = AbstractType::Handle(zone, Type::DynamicType());
// Leave the temporary type arguments at indices [0..offset[ as null.
for (intptr_t i = 0; i < num_type_parameters; i++) {
// If no type parameters were provided, a raw type is desired, so we
// create a vector of dynamic.
if (!arguments.IsNull()) {
type_arg = arguments.TypeAt(i);
// The parsed type_arg may or may not be finalized.
if (type_arg.IsTypeRef()) {
// Dereferencing the TypeRef 'rotates' the cycle in the recursive
// type argument, so that the top level type arguments of the type
// do not start with a TypeRef, for better readability and possibly
// fewer later dereferences in various type traversal routines.
// This rotation is not required for correctness.
// The cycle containing TypeRefs always involves type arguments of
// the super class in the flatten argument vector, so it is safe to
// remove TypeRefs from type arguments corresponding to the type
// parameters of the type class.
// Such TypeRefs may appear after instantiation of types at runtime.
type_arg = TypeRef::Cast(type_arg).type();
}
}
full_arguments.SetTypeAt(offset + i, type_arg);
}
// Replace the compile-time argument vector (of length zero or
// num_type_parameters) of this type being finalized with the still
// unfinalized run-time argument vector (of length num_type_arguments).
// This type being finalized may be recursively reached via bounds
// checking or type arguments of its super type.
type.set_arguments(full_arguments);
// Finalize the current type arguments of the type, which are still the
// parsed type arguments.
if (!arguments.IsNull()) {
for (intptr_t i = 0; i < num_type_parameters; i++) {
type_arg = full_arguments.TypeAt(offset + i);
if (!type_arg.IsBeingFinalized()) {
type_arg = FinalizeType(type_arg, kFinalize, pending_types);
} else {
ASSERT(type_arg.IsTypeParameter());
// The bound of the type parameter is still being finalized.
}
full_arguments.SetTypeAt(offset + i, type_arg);
}
}
if (offset > 0) {
TrailPtr trail = new Trail(zone, 4);
FillAndFinalizeTypeArguments(zone, type_class, full_arguments, offset,
pending_types, trail);
}
if (full_arguments.IsRaw(0, num_type_arguments)) {
// The parameterized_type is raw. Set its argument vector to null, which
// is more efficient in type tests.
full_arguments = TypeArguments::null();
}
type.set_arguments(full_arguments);
} else {
ASSERT(full_arguments.IsNull()); // Use null vector for raw type.
}
}
ASSERT(full_arguments.IsNull() ||
!full_arguments.IsRaw(0, num_type_arguments));
return full_arguments.IsNull() ? 0 : full_arguments.Length();
}
// Finalize the type argument vector 'arguments' of the type defined by the
// class 'cls' parameterized with the type arguments 'cls_args'.
// The vector 'cls_args' is already initialized as a subvector at the correct
// position in the passed in 'arguments' vector.
// The subvector 'cls_args' has length cls.NumTypeParameters() and starts at
// offset cls.NumTypeArguments() - cls.NumTypeParameters() of the 'arguments'
// vector.
// The type argument vector of cls may overlap the type argument vector of its
// super class. In case of an overlap, the overlapped type arguments of the
// super class are already initialized. The still uninitialized ones have an
// offset smaller than 'num_uninitialized_arguments'.
// Example 1 (without overlap):
// Declared: class C<K, V> extends B<V> { ... }
// class B<T> extends A<int> { ... }
// Input: C<String, double> expressed as
// cls = C, arguments = [dynamic, dynamic, String, double],
// num_uninitialized_arguments = 2,
// i.e. cls_args = [String, double], offset = 2, length = 2.
// Output: arguments = [int, double, String, double]
// Example 2 (with overlap):
// Declared: class C<K, V> extends B<K> { ... }
// class B<T> extends A<int> { ... }
// Input: C<String, double> expressed as
// cls = C, arguments = [dynamic, String, double],
// num_uninitialized_arguments = 1,
// i.e. cls_args = [String, double], offset = 1, length = 2.
// Output: arguments = [int, String, double]
//
// It is too early to canonicalize the type arguments of the vector, because
// several type argument vectors may be mutually recursive and finalized at the
// same time. Canonicalization happens when pending types are processed.
// The trail is required to correctly instantiate a recursive type argument
// of the super type.
void ClassFinalizer::FillAndFinalizeTypeArguments(
Zone* zone,
const Class& cls,
const TypeArguments& arguments,
intptr_t num_uninitialized_arguments,
PendingTypes* pending_types,
TrailPtr trail) {
ASSERT(arguments.Length() >= cls.NumTypeArguments());
if (!cls.is_type_finalized()) {
#if defined(DART_PRECOMPILED_RUNTIME)
UNREACHABLE();
#else
FinalizeTypeParameters(zone, cls, Object::null_function_type(), kFinalize);
#endif // defined(DART_PRECOMPILED_RUNTIME)
}
AbstractType& super_type = AbstractType::Handle(zone, cls.super_type());
if (!super_type.IsNull()) {
const Class& super_class = Class::Handle(zone, super_type.type_class());
const intptr_t num_super_type_params = super_class.NumTypeParameters();
const intptr_t num_super_type_args = super_class.NumTypeArguments();
if (!super_type.IsFinalized() && !super_type.IsBeingFinalized()) {
super_type = FinalizeType(super_type, kFinalize, pending_types);
cls.set_super_type(super_type);
}
TypeArguments& super_type_args =
TypeArguments::Handle(zone, super_type.arguments());
// Offset of super type's type parameters in cls' type argument vector.
const intptr_t super_offset = num_super_type_args - num_super_type_params;
// If the super type is raw (i.e. super_type_args is null), set to dynamic.
AbstractType& super_type_arg =
AbstractType::Handle(zone, Type::DynamicType());
for (intptr_t i = super_offset; i < num_uninitialized_arguments; i++) {
if (!super_type_args.IsNull()) {
super_type_arg = super_type_args.TypeAt(i);
if (!super_type_arg.IsTypeRef()) {
if (super_type_arg.IsBeingFinalized()) {
// A type parameter being finalized indicates an unfinalized bound,
// but the bound is not relevant here. Its index is finalized.
if (!super_type_arg.IsTypeParameter()) {
if (super_type_arg.IsType()) {
CheckRecursiveType(super_type_arg, pending_types);
} else {
// The spec prohibits a typedef-declared function type to refer
// to itself. However, self-reference can occur via type
// arguments of the base class,
// e.g. `class Derived extends Base<TypeDef<Derived>> {}`.
ASSERT(super_type_arg.IsFunctionType());
}
if (FLAG_trace_type_finalization) {
THR_Print(
"Creating TypeRef '%s': '%s'\n",
String::Handle(zone, super_type_arg.Name()).ToCString(),
super_type_arg.ToCString());
}
super_type_arg = TypeRef::New(super_type_arg);
}
super_type_args.SetTypeAt(i, super_type_arg);
} else {
if (!super_type_arg.IsFinalized()) {
super_type_arg =
FinalizeType(super_type_arg, kFinalize, pending_types);
super_type_args.SetTypeAt(i, super_type_arg);
// Note that super_type_arg may still not be finalized here, in
// which case it is a TypeRef to a legal recursive type.
}
}
}
// Instantiate super_type_arg with the current argument vector.
if (!super_type_arg.IsInstantiated()) {
if (FLAG_trace_type_finalization && super_type_arg.IsTypeRef()) {
AbstractType& ref_type = AbstractType::Handle(
zone, TypeRef::Cast(super_type_arg).type());
THR_Print(
"Instantiating TypeRef '%s': '%s'\n"
" instantiator: '%s'\n",
String::Handle(zone, super_type_arg.Name()).ToCString(),
ref_type.ToCString(), arguments.ToCString());
}
// In the typical case of an F-bounded type, the instantiation of the
// super_type_arg from arguments is a fixpoint. Take the shortcut.
// Example: class B<T>; class D<T> extends B<D<T>>;
// While finalizing D<T>, the super type arg D<T> (a typeref) gets
// instantiated from vector [T], yielding itself.
if (super_type_arg.IsTypeRef() &&
(super_type_arg.arguments() == arguments.ptr())) {
ASSERT(super_type_arg.IsBeingFinalized());
arguments.SetTypeAt(i, super_type_arg);
continue;
}
super_type_arg = super_type_arg.InstantiateFrom(
arguments, Object::null_type_arguments(), kNoneFree, Heap::kOld,
trail);
if (super_type_arg.IsBeingFinalized() &&
!super_type_arg.IsTypeParameter()) {
// The super_type_arg was instantiated from a type being finalized.
// We need to finish finalizing its type arguments, unless it is a
// type parameter, in which case there is nothing more to do.
AbstractType& unfinalized_type = AbstractType::Handle(zone);
if (super_type_arg.IsTypeRef()) {
unfinalized_type = TypeRef::Cast(super_type_arg).type();
} else {
ASSERT(super_type_arg.IsType());
unfinalized_type = super_type_arg.ptr();
}
if (FLAG_trace_type_finalization) {
THR_Print(
"Instantiated unfinalized '%s': '%s'\n",
String::Handle(zone, unfinalized_type.Name()).ToCString(),
unfinalized_type.ToCString());
}
if (unfinalized_type.IsType()) {
CheckRecursiveType(unfinalized_type, pending_types);
pending_types->Add(unfinalized_type);
}
const Class& super_cls =
Class::Handle(zone, unfinalized_type.type_class());
const TypeArguments& super_args =
TypeArguments::Handle(zone, unfinalized_type.arguments());
// Mark as finalized before finalizing to avoid cycles.
unfinalized_type.SetIsFinalized();
// Although the instantiator is different between cls and super_cls,
// we still need to pass the current instantiation trail as to avoid
// divergence. Finalizing the type arguments of super_cls may indeed
// recursively require instantiating the same type_refs already
// present in the trail (see issue #29949).
FillAndFinalizeTypeArguments(
zone, super_cls, super_args,
super_cls.NumTypeArguments() - super_cls.NumTypeParameters(),
pending_types, trail);
if (FLAG_trace_type_finalization) {
THR_Print(
"Finalized instantiated '%s': '%s'\n",
String::Handle(zone, unfinalized_type.Name()).ToCString(),
unfinalized_type.ToCString());
}
}
}
}
arguments.SetTypeAt(i, super_type_arg);
}
FillAndFinalizeTypeArguments(zone, super_class, arguments, super_offset,
pending_types, trail);
}
}
TypeArgumentsPtr ClassFinalizer::FinalizeTypeArguments(
Zone* zone,
const TypeArguments& type_args,
FinalizationKind finalization,
PendingTypes* pending_types) {
if (type_args.IsNull()) return TypeArguments::null();
ASSERT(type_args.ptr() != Object::empty_type_arguments().ptr());
const intptr_t len = type_args.Length();
AbstractType& type = AbstractType::Handle(zone);
AbstractType& finalized_type = AbstractType::Handle(zone);
for (intptr_t i = 0; i < len; i++) {
type = type_args.TypeAt(i);
if (type.IsBeingFinalized()) {
ASSERT(finalization < kCanonicalize);
continue;
}
finalized_type = FinalizeType(type, kFinalize, pending_types);
if (type.ptr() != finalized_type.ptr()) {
type_args.SetTypeAt(i, finalized_type);
}
}
if (finalization >= kCanonicalize) {
return type_args.Canonicalize(Thread::Current(), nullptr);
}
return type_args.ptr();
}
AbstractTypePtr ClassFinalizer::FinalizeType(const AbstractType& type,
FinalizationKind finalization,
PendingTypes* pending_types) {
// Only the 'root' type of the graph can be canonicalized, after all depending
// types have been bound checked.
ASSERT((pending_types == NULL) || (finalization < kCanonicalize));
if (type.IsFinalized()) {
// Ensure type is canonical if canonicalization is requested.
if ((finalization >= kCanonicalize) && !type.IsCanonical() &&
!type.IsBeingFinalized()) {
return type.Canonicalize(Thread::Current(), nullptr);
}
return type.ptr();
}
Thread* thread = Thread::Current();
Zone* zone = thread->zone();
if (type.IsTypeRef()) {
if (type.IsBeingFinalized()) {
// The referenced type will be finalized later by the code that set the
// is_being_finalized mark bit.
return type.ptr();
}
AbstractType& ref_type =
AbstractType::Handle(zone, TypeRef::Cast(type).type());
ref_type = FinalizeType(ref_type, finalization, pending_types);
TypeRef::Cast(type).set_type(ref_type);
return type.ptr();
}
// Recursive types must be processed in FillAndFinalizeTypeArguments() and
// cannot be encountered here.
ASSERT(!type.IsBeingFinalized());
// Mark the type as being finalized in order to detect self reference.
type.SetIsBeingFinalized();
if (FLAG_trace_type_finalization) {
THR_Print("Finalizing type '%s'\n",
String::Handle(zone, type.Name()).ToCString());
}
if (type.IsTypeParameter()) {
const TypeParameter& type_parameter = TypeParameter::Cast(type);
const Class& parameterized_class =
Class::Handle(zone, type_parameter.parameterized_class());
// The base and index of a function type parameter are eagerly calculated
// upon loading and do not require adjustment here.
if (!parameterized_class.IsNull()) {
// The index must reflect the position of this type parameter in the type
// arguments vector of its parameterized class. The offset to add is the
// number of type arguments in the super type, which is equal to the
// difference in number of type arguments and type parameters of the
// parameterized class.
const intptr_t offset = parameterized_class.NumTypeArguments() -
parameterized_class.NumTypeParameters();
type_parameter.set_base(offset); // Informative, but not needed.
type_parameter.set_index(type_parameter.index() + offset);
// Remove the reference to the parameterized class.
type_parameter.set_parameterized_class_id(kClassCid);
}
type_parameter.SetIsFinalized();
AbstractType& upper_bound = AbstractType::Handle(zone);
upper_bound = type_parameter.bound();
if (!upper_bound.IsBeingFinalized()) {
upper_bound = FinalizeType(upper_bound, kFinalize);
type_parameter.set_bound(upper_bound);
}
if (FLAG_trace_type_finalization) {
THR_Print("Done finalizing type parameter at index %" Pd "\n",
type_parameter.index());
}
if (finalization >= kCanonicalize) {
return type_parameter.Canonicalize(thread, nullptr);
}
return type_parameter.ptr();
}
// If the type is a function type, we also need to finalize the types in its
// signature, i.e. finalize the result type and parameter types of the
// signature function of this function type.
if (type.IsFunctionType()) {
return FinalizeSignature(zone, FunctionType::Cast(type), finalization,
pending_types);
}
// This type is the root type of the type graph if no pending types queue is
// allocated yet. A function type is a collection of types, but not a root.
const bool is_root_type = pending_types == NULL;
if (is_root_type) {
pending_types = new PendingTypes(zone, 4);
}
// At this point, we can only have a Type.
ASSERT(type.IsType());
pending_types->Add(type);
const intptr_t num_expanded_type_arguments =
ExpandAndFinalizeTypeArguments(zone, type, pending_types);
// Self referencing types may get finalized indirectly.
if (!type.IsFinalized()) {
if (FLAG_trace_type_finalization) {
THR_Print("Marking type '%s' as finalized\n",
String::Handle(zone, type.Name()).ToCString());
}
// Mark the type as finalized.
type.SetIsFinalized();
}
if (FLAG_trace_type_finalization) {
THR_Print("Done finalizing type '%s' with %" Pd " type args: %s\n",
String::Handle(zone, type.Name()).ToCString(),
num_expanded_type_arguments, type.ToCString());
}
if (finalization >= kCanonicalize) {
if (FLAG_trace_type_finalization) {
THR_Print("Canonicalizing type '%s'\n",
String::Handle(zone, type.Name()).ToCString());
AbstractType& canonical_type =
AbstractType::Handle(zone, type.Canonicalize(thread, nullptr));
THR_Print("Done canonicalizing type '%s'\n",
String::Handle(zone, canonical_type.Name()).ToCString());
return canonical_type.ptr();
}
return type.Canonicalize(thread, nullptr);
} else {
return type.ptr();
}
}
AbstractTypePtr ClassFinalizer::FinalizeSignature(Zone* zone,
const FunctionType& signature,
FinalizationKind finalization,
PendingTypes* pending_types) {
// Finalize signature type parameter upper bounds and default args.
FinalizeTypeParameters(zone, Object::null_class(), signature, finalization,
pending_types);
AbstractType& type = AbstractType::Handle(zone);
AbstractType& finalized_type = AbstractType::Handle(zone);
// Finalize result type.
type = signature.result_type();
finalized_type = FinalizeType(type, kFinalize, pending_types);
if (finalized_type.ptr() != type.ptr()) {
signature.set_result_type(finalized_type);
}
// Finalize formal parameter types.
const intptr_t num_parameters = signature.NumParameters();
for (intptr_t i = 0; i < num_parameters; i++) {
type = signature.ParameterTypeAt(i);
finalized_type = FinalizeType(type, kFinalize, pending_types);
if (type.ptr() != finalized_type.ptr()) {
signature.SetParameterTypeAt(i, finalized_type);
}
}
if (FLAG_trace_type_finalization) {
THR_Print("Marking function type '%s' as finalized\n",
String::Handle(zone, signature.Name()).ToCString());
}
signature.SetIsFinalized();
if (finalization >= kCanonicalize) {
return signature.Canonicalize(Thread::Current(), nullptr);
}
return signature.ptr();
}
#if !defined(DART_PRECOMPILED_RUNTIME)
#if defined(TARGET_ARCH_X64)
static bool IsPotentialExactGeneric(const AbstractType& type) {
// TODO(dartbug.com/34170) Investigate supporting this for fields with types
// that depend on type parameters of the enclosing class.
if (type.IsType() && !type.IsDartFunctionType() && type.IsInstantiated() &&
!type.IsFutureOrType()) {
const Class& cls = Class::Handle(type.type_class());
return cls.IsGeneric();
}
return false;
}
#else
// TODO(dartbug.com/34170) Support other architectures.
static bool IsPotentialExactGeneric(const AbstractType& type) {
return false;
}
#endif
void ClassFinalizer::FinalizeMemberTypes(const Class& cls) {
// Note that getters and setters are explicitly listed as such in the list of
// functions of a class, so we do not need to consider fields as implicitly
// generating getters and setters.
// Most overriding conflicts are only static warnings, i.e. they are not
// reported as compile-time errors by the vm.
// Static warning examples are:
// - a static getter 'v' conflicting with an inherited instance setter 'v='.
// - a static setter 'v=' conflicting with an inherited instance member 'v'.
// - an instance member 'v' conflicting with an accessible static member 'v'
// or 'v=' of a super class (except that an instance method 'v' does not
// conflict with an accessible static setter 'v=' of a super class).
// The compile-time errors we report are:
// - a static member 'v' conflicting with an inherited instance member 'v'.
// - a static setter 'v=' conflicting with an inherited instance setter 'v='.
// - an instance method conflicting with an inherited instance field or
// instance getter.
// - an instance field or instance getter conflicting with an inherited
// instance method.
// Finalize type of fields and check for conflicts in super classes.
auto isolate_group = IsolateGroup::Current();
Zone* zone = Thread::Current()->zone();
Array& array = Array::Handle(zone, cls.fields());
Field& field = Field::Handle(zone);
AbstractType& type = AbstractType::Handle(zone);
Function& function = Function::Handle(zone);
FunctionType& signature = FunctionType::Handle(zone);
const intptr_t num_fields = array.Length();
const bool track_exactness = isolate_group->use_field_guards();
for (intptr_t i = 0; i < num_fields; i++) {
field ^= array.At(i);
type = field.type();
type = FinalizeType(type);
field.SetFieldType(type);
if (track_exactness && IsPotentialExactGeneric(type)) {
field.set_static_type_exactness_state(
StaticTypeExactnessState::Uninitialized());
}
function = field.InitializerFunction();
if (!function.IsNull()) {
// TODO(regis): It looks like the initializer is never set at this point.
// Remove this finalization code?
signature = function.signature();
signature ^= FinalizeType(signature);
function.SetSignature(signature);
}
}
// Finalize function signatures and check for conflicts in super classes and
// interfaces.
array = cls.current_functions();
const intptr_t num_functions = array.Length();
for (intptr_t i = 0; i < num_functions; i++) {
function ^= array.At(i);
signature = function.signature();
signature ^= FinalizeType(signature);
function.SetSignature(signature);
if (function.IsSetterFunction() || function.IsImplicitSetterFunction()) {
continue;
}
}
}
// For a class used as an interface marks this class and all its superclasses
// implemented.
//
// Does not mark its interfaces implemented because those would already be
// marked as such.
static void MarkImplemented(Zone* zone, const Class& iface) {
if (iface.is_implemented()) {
return;
}
Class& cls = Class::Handle(zone, iface.ptr());
AbstractType& type = AbstractType::Handle(zone);
while (!cls.is_implemented()) {
cls.set_is_implemented();
type = cls.super_type();
if (type.IsNull() || type.IsObjectType()) {
break;
}
cls = type.type_class();
}
}
#endif // !defined(DART_PRECOMPILED_RUNTIME)
void ClassFinalizer::FinalizeTypesInClass(const Class& cls) {
Thread* thread = Thread::Current();
HANDLESCOPE(thread);
cls.EnsureDeclarationLoaded();
if (cls.is_type_finalized()) {
return;
}
#if defined(DART_PRECOMPILED_RUNTIME)
UNREACHABLE();
#else
Zone* zone = thread->zone();
SafepointWriteRwLocker ml(thread, thread->isolate_group()->program_lock());
if (cls.is_type_finalized()) {
return;
}
if (FLAG_trace_class_finalization) {
THR_Print("Finalize types in %s\n", cls.ToCString());
}
bool implements_finalizable =
cls.Name() == Symbols::Finalizable().ptr() &&
Library::UrlOf(cls.library()) == Symbols::DartFfi().ptr();
// Finalize super class.
Class& super_class = Class::Handle(zone, cls.SuperClass());
if (!super_class.IsNull()) {
FinalizeTypesInClass(super_class);
}
// Finalize type parameters before finalizing the super type.
FinalizeTypeParameters(zone, cls, Object::null_function_type(),
kCanonicalize);
ASSERT(super_class.ptr() == cls.SuperClass()); // Not modified.
ASSERT(super_class.IsNull() || super_class.is_type_finalized());
// Finalize super type.
AbstractType& super_type = AbstractType::Handle(zone, cls.super_type());
if (!super_type.IsNull()) {
super_type = FinalizeType(super_type);
cls.set_super_type(super_type);
implements_finalizable |=
Class::ImplementsFinalizable(super_type.type_class());
}
// Finalize interface types (but not necessarily interface classes).
const auto& interface_types = Array::Handle(zone, cls.interfaces());
auto& interface_type = AbstractType::Handle(zone);
auto& interface_class = Class::Handle(zone);
for (intptr_t i = 0; i < interface_types.Length(); i++) {
interface_type ^= interface_types.At(i);
interface_type = FinalizeType(interface_type);
interface_class = interface_type.type_class();
ASSERT(!interface_class.IsNull());
FinalizeTypesInClass(interface_class);
interface_types.SetAt(i, interface_type);
implements_finalizable |=
Class::ImplementsFinalizable(interface_type.type_class());
}
cls.set_implements_finalizable(implements_finalizable);
cls.set_is_type_finalized();
RegisterClassInHierarchy(thread->zone(), cls);
#endif // defined(DART_PRECOMPILED_RUNTIME)
}
#if !defined(DART_PRECOMPILED_RUNTIME)
void ClassFinalizer::RegisterClassInHierarchy(Zone* zone, const Class& cls) {
auto& type = AbstractType::Handle(zone, cls.super_type());
auto& other_cls = Class::Handle(zone);
// Add this class to the direct subclasses of the superclass, unless the
// superclass is Object.
if (!type.IsNull() && !type.IsObjectType()) {
other_cls = cls.SuperClass();
ASSERT(!other_cls.IsNull());
other_cls.AddDirectSubclass(cls);
}
// Add this class as an implementor to the implemented interface's type
// classes.
const auto& interfaces = Array::Handle(zone, cls.interfaces());
const intptr_t mixin_index =
cls.is_transformed_mixin_application() ? interfaces.Length() - 1 : -1;
for (intptr_t i = 0; i < interfaces.Length(); ++i) {
type ^= interfaces.At(i);
other_cls = type.type_class();
MarkImplemented(zone, other_cls);
other_cls.AddDirectImplementor(cls, /* is_mixin = */ i == mixin_index);
}
}
#endif // defined(DART_PRECOMPILED_RUNTIME)
void ClassFinalizer::FinalizeClass(const Class& cls) {
ASSERT(cls.is_type_finalized());
if (cls.is_finalized()) {
return;
}
#if defined(DART_PRECOMPILED_RUNTIME)
UNREACHABLE();
#else
Thread* thread = Thread::Current();
HANDLESCOPE(thread);
if (FLAG_trace_class_finalization) {
THR_Print("Finalize %s\n", cls.ToCString());
}
#if defined(SUPPORT_TIMELINE)
TimelineBeginEndScope tbes(thread, Timeline::GetCompilerStream(),
"FinalizeClass");
if (tbes.enabled()) {
tbes.SetNumArguments(1);
tbes.CopyArgument(0, "class", cls.ToCString());
}
#endif // defined(SUPPORT_TIMELINE)
// If loading from a kernel, make sure that the class is fully loaded.
ASSERT(cls.IsTopLevel() || (cls.kernel_offset() > 0));
if (!cls.is_loaded()) {
kernel::KernelLoader::FinishLoading(cls);
if (cls.is_finalized()) {
return;
}
}
// Ensure super class is finalized.
const Class& super = Class::Handle(cls.SuperClass());
if (!super.IsNull()) {
FinalizeClass(super);
if (cls.is_finalized()) {
return;
}
}
// Mark as loaded and finalized.
cls.Finalize();
if (FLAG_print_classes) {
PrintClassInformation(cls);
}
FinalizeMemberTypes(cls);
if (cls.is_enum_class() && !FLAG_precompiled_mode) {
AllocateEnumValues(cls);
}
// The rest of finalization for non-top-level class has to be done with
// stopped mutators. It will be done by AllocateFinalizeClass. before new
// instance of a class is created in GetAllocationStubForClass.
if (cls.IsTopLevel()) {
cls.set_is_allocate_finalized();
}
#endif // defined(DART_PRECOMPILED_RUNTIME)
}
#if !defined(DART_PRECOMPILED_RUNTIME)
ErrorPtr ClassFinalizer::AllocateFinalizeClass(const Class& cls) {
ASSERT(IsolateGroup::Current()->program_lock()->IsCurrentThreadWriter());
ASSERT(cls.is_finalized());
ASSERT(!cls.is_allocate_finalized());
Thread* thread = Thread::Current();
HANDLESCOPE(thread);
if (FLAG_trace_class_finalization) {
THR_Print("Allocate finalize %s\n", cls.ToCString());
}
#if defined(SUPPORT_TIMELINE)
TimelineBeginEndScope tbes(thread, Timeline::GetCompilerStream(),
"AllocateFinalizeClass");
if (tbes.enabled()) {
tbes.SetNumArguments(1);
tbes.CopyArgument(0, "class", cls.ToCString());
}
#endif // defined(SUPPORT_TIMELINE)
// Run additional checks after all types are finalized.
if (FLAG_use_cha_deopt && !cls.IsTopLevel()) {
{
GrowableArray<intptr_t> cids;
CollectFinalizedSuperClasses(cls, &cids);
CollectImmediateSuperInterfaces(cls, &cids);
RemoveCHAOptimizedCode(cls, cids);
}
Zone* zone = thread->zone();
ClassTable* class_table = thread->isolate_group()->class_table();
auto& interface_class = Class::Handle(zone);
// We scan every interface this [cls] implements and invalidate all CHA
// code which depends on knowing the implementors of that interface.
{
GrowableArray<intptr_t> cids;
InterfaceFinder finder(zone, class_table, &cids);
finder.FindAllInterfaces(cls);
for (intptr_t j = 0; j < cids.length(); ++j) {
interface_class = class_table->At(cids[j]);
interface_class.DisableCHAImplementorUsers();
}
}
}
cls.set_is_allocate_finalized();
return Error::null();
}
ErrorPtr ClassFinalizer::LoadClassMembers(const Class& cls) {
ASSERT(IsolateGroup::Current()->program_lock()->IsCurrentThreadWriter());
ASSERT(!cls.is_finalized());
LongJumpScope jump;
if (setjmp(*jump.Set()) == 0) {
#if !defined(DART_PRECOMPILED_RUNTIME)
cls.EnsureDeclarationLoaded();
#endif
ASSERT(cls.is_type_finalized());
ClassFinalizer::FinalizeClass(cls);
return Error::null();
} else {
return Thread::Current()->StealStickyError();
}
}
// Eagerly allocate instances for enumeration values by evaluating
// static const field 'values'. Also, pre-allocate
// deleted sentinel value. This is needed to correctly
// migrate enumeration values in case of hot reload.
void ClassFinalizer::AllocateEnumValues(const Class& enum_cls) {
Thread* thread = Thread::Current();
Zone* zone = thread->zone();
ObjectStore* object_store = thread->isolate_group()->object_store();
const auto& values_field =
Field::Handle(zone, enum_cls.LookupStaticField(Symbols::Values()));
if (!values_field.IsNull()) {
ASSERT(values_field.is_static() && values_field.is_const());
const auto& values =
Object::Handle(zone, values_field.StaticConstFieldValue());
if (values.IsError()) {
ReportError(Error::Cast(values));
}
ASSERT(values.IsArray());
}
const auto& index_field =
Field::Handle(zone, object_store->enum_index_field());
ASSERT(!index_field.IsNull());
const auto& name_field = Field::Handle(zone, object_store->enum_name_field());
ASSERT(!name_field.IsNull());
const auto& enum_name = String::Handle(zone, enum_cls.ScrubbedName());
const auto& sentinel_ident = String::Handle(
zone,
Symbols::FromConcat(thread, Symbols::_DeletedEnumPrefix(), enum_name));
auto& sentinel_value =
Instance::Handle(zone, Instance::New(enum_cls, Heap::kOld));
sentinel_value.SetField(index_field, Smi::Handle(zone, Smi::New(-1)));
sentinel_value.SetField(name_field, sentinel_ident);
sentinel_value = sentinel_value.Canonicalize(thread);
ASSERT(!sentinel_value.IsNull());
ASSERT(sentinel_value.IsCanonical());
const auto& sentinel_field = Field::Handle(
zone, enum_cls.LookupStaticField(Symbols::_DeletedEnumSentinel()));
ASSERT(!sentinel_field.IsNull());
// The static const field contains `Object::null()` instead of
// `Object::sentinel()` - so it's not considered an initializing store.
sentinel_field.SetStaticConstFieldValue(sentinel_value,
/*assert_initializing_store*/ false);
}
void ClassFinalizer::PrintClassInformation(const Class& cls) {
Thread* thread = Thread::Current();
HANDLESCOPE(thread);
const String& class_name = String::Handle(cls.Name());
THR_Print("class '%s'", class_name.ToCString());
const Library& library = Library::Handle(cls.library());
if (!library.IsNull()) {
THR_Print(" library '%s%s':\n", String::Handle(library.url()).ToCString(),
String::Handle(library.private_key()).ToCString());
} else {
THR_Print(" (null library):\n");
}
const AbstractType& super_type = AbstractType::Handle(cls.super_type());
if (super_type.IsNull()) {
THR_Print(" Super: NULL");
} else {
const String& super_name = String::Handle(super_type.Name());
THR_Print(" Super: %s", super_name.ToCString());
}
const Array& interfaces_array = Array::Handle(cls.interfaces());
if (interfaces_array.Length() > 0) {
THR_Print("; interfaces: ");
AbstractType& interface = AbstractType::Handle();
intptr_t len = interfaces_array.Length();
for (intptr_t i = 0; i < len; i++) {
interface ^= interfaces_array.At(i);
THR_Print(" %s ", interface.ToCString());
}
}
THR_Print("\n");
const Array& functions_array = Array::Handle(cls.current_functions());
Function& function = Function::Handle();
intptr_t len = functions_array.Length();
for (intptr_t i = 0; i < len; i++) {
function ^= functions_array.At(i);
THR_Print(" %s\n", function.ToCString());
}
const Array& fields_array = Array::Handle(cls.fields());
Field& field = Field::Handle();
len = fields_array.Length();
for (intptr_t i = 0; i < len; i++) {
field ^= fields_array.At(i);
THR_Print(" %s\n", field.ToCString());
}
}
#endif // !defined(DART_PRECOMPILED_RUNTIME)
void ClassFinalizer::ReportError(const Error& error) {
Report::LongJump(error);
UNREACHABLE();
}
void ClassFinalizer::ReportError(const char* format, ...) {
va_list args;
va_start(args, format);
const Script& null_script = Script::Handle();
Report::MessageV(Report::kError, null_script, TokenPosition::kNoSource,
Report::AtLocation, format, args);
va_end(args);
UNREACHABLE();
}
#if !defined(DART_PRECOMPILED_RUNTIME)
void ClassFinalizer::VerifyImplicitFieldOffsets() {
#ifdef DEBUG
Thread* thread = Thread::Current();
auto isolate_group = thread->isolate_group();
if (isolate_group->obfuscate()) {
// Field names are obfuscated.
return;
}
Zone* zone = thread->zone();
const ClassTable& class_table = *(isolate_group->class_table());
Class& cls = Class::Handle(zone);
Array& fields_array = Array::Handle(zone);
Field& field = Field::Handle(zone);
String& name = String::Handle(zone);
String& expected_name = String::Handle(zone);
Error& error = Error::Handle(zone);
TypeParameter& type_param = TypeParameter::Handle(zone);
// Now verify field offsets of '_ByteBuffer' class.
cls = class_table.At(kByteBufferCid);
error = cls.EnsureIsFinalized(thread);
ASSERT(error.IsNull());
fields_array ^= cls.fields();
ASSERT(fields_array.Length() == ByteBuffer::NumberOfFields());
field ^= fields_array.At(0);
ASSERT(field.HostOffset() == ByteBuffer::data_offset());
name ^= field.name();
expected_name ^= String::New("_data");
ASSERT(String::EqualsIgnoringPrivateKey(name, expected_name));
// Now verify field offsets of 'Pointer' class.
cls = class_table.At(kPointerCid);
error = cls.EnsureIsFinalized(thread);
ASSERT(error.IsNull());
ASSERT(cls.NumTypeParameters() == 1);
type_param = cls.TypeParameterAt(0);
ASSERT(Pointer::kNativeTypeArgPos == type_param.index());
#endif
}
void ClassFinalizer::SortClasses() {
auto T = Thread::Current();
StackZone stack_zone(T);
auto Z = T->zone();
auto IG = T->isolate_group();
// Prevent background compiler from adding deferred classes or canonicalizing
// new types while classes are being sorted and type hashes are modified.
NoBackgroundCompilerScope no_bg_compiler(T);
SafepointWriteRwLocker ml(T, T->isolate_group()->program_lock());
ClassTable* table = IG->class_table();
intptr_t num_cids = table->NumCids();
std::unique_ptr<intptr_t[]> old_to_new_cid(new intptr_t[num_cids]);
for (intptr_t cid = 0; cid < kNumPredefinedCids; cid++) {
old_to_new_cid[cid] = cid; // The predefined classes cannot change cids.
}
for (intptr_t cid = kNumPredefinedCids; cid < num_cids; cid++) {
old_to_new_cid[cid] = -1;
}
intptr_t next_new_cid = kNumPredefinedCids;
GrowableArray<intptr_t> dfs_stack;
Class& cls = Class::Handle(Z);
GrowableObjectArray& subclasses = GrowableObjectArray::Handle(Z);
// Object doesn't use its subclasses list.
for (intptr_t cid = kNumPredefinedCids; cid < num_cids; cid++) {
if (!table->HasValidClassAt(cid)) {
continue;
}
cls = table->At(cid);
if (!cls.is_declaration_loaded()) {
continue;
}
if (cls.SuperClass() == IG->object_store()->object_class()) {
dfs_stack.Add(cid);
}
}
while (dfs_stack.length() > 0) {
intptr_t cid = dfs_stack.RemoveLast();
ASSERT(table->HasValidClassAt(cid));
cls = table->At(cid);
ASSERT(!cls.IsNull());
if (old_to_new_cid[cid] == -1) {
old_to_new_cid[cid] = next_new_cid++;
if (FLAG_trace_class_finalization) {
THR_Print("%" Pd ": %s, was %" Pd "\n", old_to_new_cid[cid],
cls.ToCString(), cid);
}
}
subclasses = cls.direct_subclasses();
if (!subclasses.IsNull()) {
for (intptr_t i = 0; i < subclasses.Length(); i++) {
cls ^= subclasses.At(i);
ASSERT(!cls.IsNull());
dfs_stack.Add(cls.id());
}
}
}
// Top-level classes, typedefs, patch classes, etc.
for (intptr_t cid = kNumPredefinedCids; cid < num_cids; cid++) {
if (old_to_new_cid[cid] == -1) {
old_to_new_cid[cid] = next_new_cid++;
if (FLAG_trace_class_finalization && table->HasValidClassAt(cid)) {
cls = table->At(cid);
THR_Print("%" Pd ": %s, was %" Pd "\n", old_to_new_cid[cid],
cls.ToCString(), cid);
}
}
}
ASSERT(next_new_cid == num_cids);
RemapClassIds(old_to_new_cid.get());
RehashTypes(); // Types use cid's as part of their hashes.
IG->RehashConstants(); // Const objects use cid's as part of their hashes.
}
class CidRewriteVisitor : public ObjectVisitor {
public:
explicit CidRewriteVisitor(intptr_t* old_to_new_cids)
: old_to_new_cids_(old_to_new_cids) {}
intptr_t Map(intptr_t cid) {
ASSERT(cid != -1);
return old_to_new_cids_[cid];
}
void VisitObject(ObjectPtr obj) {
if (obj->IsClass()) {
ClassPtr cls = Class::RawCast(obj);
const classid_t old_cid = cls->untag()->id_;
if (ClassTable::IsTopLevelCid(old_cid)) {
// We don't remap cids of top level classes.
return;
}
cls->untag()->id_ = Map(old_cid);
} else if (obj->IsField()) {
FieldPtr field = Field::RawCast(obj);
field->untag()->guarded_cid_ = Map(field->untag()->guarded_cid_);
field->untag()->is_nullable_ = Map(field->untag()->is_nullable_);
} else if (obj->IsTypeParameter()) {
TypeParameterPtr param = TypeParameter::RawCast(obj);
param->untag()->parameterized_class_id_ =
Map(param->untag()->parameterized_class_id_);
} else if (obj->IsType()) {
TypePtr type = Type::RawCast(obj);
type->untag()->type_class_id_ = Map(type->untag()->type_class_id_);
} else {
intptr_t old_cid = obj->GetClassId();
intptr_t new_cid = Map(old_cid);
if (old_cid != new_cid) {
// Don't touch objects that are unchanged. In particular, Instructions,
// which are write-protected.
obj->untag()->SetClassIdUnsynchronized(new_cid);
}
}
}
private:
intptr_t* old_to_new_cids_;
};
void ClassFinalizer::RemapClassIds(intptr_t* old_to_new_cid) {
Thread* T = Thread::Current();
IsolateGroup* IG = T->isolate_group();
// Code, ICData, allocation stubs have now-invalid cids.
ClearAllCode();
{
// The [HeapIterationScope] also safepoints all threads.
HeapIterationScope his(T);
IG->shared_class_table()->Remap(old_to_new_cid);
IG->set_remapping_cids(true);
// Update the class table. Do it before rewriting cids in headers, as
// the heap walkers load an object's size *after* calling the visitor.
IG->class_table()->Remap(old_to_new_cid);
// Rewrite cids in headers and cids in Classes, Fields, Types and
// TypeParameters.
{
CidRewriteVisitor visitor(old_to_new_cid);
IG->heap()->VisitObjects(&visitor);
}
IG->set_remapping_cids(false);
#if defined(DEBUG)
IG->class_table()->Validate();
#endif
}
#if defined(DEBUG)
IG->heap()->Verify();
#endif
}
// Clears the cached canonicalized hash codes for all instances which directly
// (or indirectly) depend on class ids.
//
// In the Dart VM heap the following instances directly use cids for the
// computation of canonical hash codes:
//
// * TypePtr (due to UntaggedType::type_class_id_)
// * TypeParameterPtr (due to UntaggedTypeParameter::parameterized_class_id_)
//
// The following instances use cids for the computation of canonical hash codes
// indirectly:
//
// * TypeRefPtr (due to UntaggedTypeRef::type_->type_class_id)
// * TypePtr (due to type arguments)
// * FunctionTypePtr (due to the result and parameter types)
// * TypeArgumentsPtr (due to type references)
// * InstancePtr (due to instance fields)
// * ArrayPtr (due to type arguments & array entries)
//
// Caching of the canonical hash codes happens for:
//
// * UntaggedType::hash_
// * UntaggedFunctionType::hash_
// * UntaggedTypeParameter::hash_
// * UntaggedTypeArguments::hash_
// * InstancePtr (weak table)
// * ArrayPtr (weak table)
//
// No caching of canonical hash codes (i.e. it gets re-computed every time)
// happens for:
//
// * TypeRefPtr (computed via UntaggedTypeRef::type_->type_class_id)
//
// Usages of canonical hash codes are:
//
// * ObjectStore::canonical_types()
// * ObjectStore::canonical_function_types()
// * ObjectStore::canonical_type_parameters()
// * ObjectStore::canonical_type_arguments()
// * Class::constants()
//
class ClearTypeHashVisitor : public ObjectVisitor {
public:
explicit ClearTypeHashVisitor(Zone* zone)
: type_param_(TypeParameter::Handle(zone)),
type_(Type::Handle(zone)),
function_type_(FunctionType::Handle(zone)),
type_args_(TypeArguments::Handle(zone)) {}
void VisitObject(ObjectPtr obj) {
if (obj->IsTypeParameter()) {
type_param_ ^= obj;
type_param_.SetHash(0);
} else if (obj->IsType()) {
type_ ^= obj;
type_.SetHash(0);
} else if (obj->IsFunctionType()) {
function_type_ ^= obj;
function_type_.SetHash(0);
} else if (obj->IsTypeArguments()) {
type_args_ ^= obj;
type_args_.SetHash(0);
}
}
private:
TypeParameter& type_param_;
Type& type_;
FunctionType& function_type_;
TypeArguments& type_args_;
};
void ClassFinalizer::RehashTypes() {
auto T = Thread::Current();
auto Z = T->zone();
auto IG = T->isolate_group();
// Clear all cached hash values.
{
HeapIterationScope his(T);
ClearTypeHashVisitor visitor(Z);
IG->heap()->VisitObjects(&visitor);
}
// Rehash the canonical Types table.
ObjectStore* object_store = IG->object_store();
Array& types = Array::Handle(Z);
Type& type = Type::Handle(Z);
{
CanonicalTypeSet types_table(Z, object_store->canonical_types());
types = HashTables::ToArray(types_table, false);
types_table.Release();
}
intptr_t dict_size = Utils::RoundUpToPowerOfTwo(types.Length() * 4 / 3);
CanonicalTypeSet types_table(
Z, HashTables::New<CanonicalTypeSet>(dict_size, Heap::kOld));
for (intptr_t i = 0; i < types.Length(); i++) {
type ^= types.At(i);
bool present = types_table.Insert(type);
// Two recursive types with different topology (and hashes) may be equal.
ASSERT(!present || type.IsRecursive());
}
object_store->set_canonical_types(types_table.Release());
// Rehash the canonical FunctionTypes table.
Array& function_types = Array::Handle(Z);
FunctionType& function_type = FunctionType::Handle(Z);
{
CanonicalFunctionTypeSet function_types_table(
Z, object_store->canonical_function_types());
function_types = HashTables::ToArray(function_types_table, false);
function_types_table.Release();
}
dict_size = Utils::RoundUpToPowerOfTwo(function_types.Length() * 4 / 3);
CanonicalFunctionTypeSet function_types_table(
Z, HashTables::New<CanonicalFunctionTypeSet>(dict_size, Heap::kOld));
for (intptr_t i = 0; i < function_types.Length(); i++) {
function_type ^= function_types.At(i);
bool present = function_types_table.Insert(function_type);
// Two recursive types with different topology (and hashes) may be equal.
ASSERT(!present || function_type.IsRecursive());
}
object_store->set_canonical_function_types(function_types_table.Release());
// Rehash the canonical TypeParameters table.
Array& typeparams = Array::Handle(Z);
TypeParameter& typeparam = TypeParameter::Handle(Z);
{
CanonicalTypeParameterSet typeparams_table(
Z, object_store->canonical_type_parameters());
typeparams = HashTables::ToArray(typeparams_table, false);
typeparams_table.Release();
}
dict_size = Utils::RoundUpToPowerOfTwo(typeparams.Length() * 4 / 3);
CanonicalTypeParameterSet typeparams_table(
Z, HashTables::New<CanonicalTypeParameterSet>(dict_size, Heap::kOld));
for (intptr_t i = 0; i < typeparams.Length(); i++) {
typeparam ^= typeparams.At(i);
bool present = typeparams_table.Insert(typeparam);
// Two recursive types with different topology (and hashes) may be equal.
ASSERT(!present || typeparam.IsRecursive());
}
object_store->set_canonical_type_parameters(typeparams_table.Release());
// Rehash the canonical TypeArguments table.
Array& typeargs = Array::Handle(Z);
TypeArguments& typearg = TypeArguments::Handle(Z);
{
CanonicalTypeArgumentsSet typeargs_table(
Z, object_store->canonical_type_arguments());
typeargs = HashTables::ToArray(typeargs_table, false);
typeargs_table.Release();
}
// The canonical constant tables use canonical hashcodes which can change
// due to cid-renumbering.
IG->RehashConstants();
dict_size = Utils::RoundUpToPowerOfTwo(typeargs.Length() * 4 / 3);
CanonicalTypeArgumentsSet typeargs_table(
Z, HashTables::New<CanonicalTypeArgumentsSet>(dict_size, Heap::kOld));
for (intptr_t i = 0; i < typeargs.Length(); i++) {
typearg ^= typeargs.At(i);
bool present = typeargs_table.Insert(typearg);
// Two recursive types with different topology (and hashes) may be equal.
ASSERT(!present || typearg.IsRecursive());
}
object_store->set_canonical_type_arguments(typeargs_table.Release());
}
void ClassFinalizer::ClearAllCode(bool including_nonchanging_cids) {
auto const thread = Thread::Current();
auto const isolate_group = thread->isolate_group();
SafepointWriteRwLocker ml(thread, isolate_group->program_lock());
StackZone stack_zone(thread);
auto const zone = thread->zone();
class ClearCodeVisitor : public FunctionVisitor {
public:
ClearCodeVisitor(Zone* zone, bool force)
: force_(force),
pool_(ObjectPool::Handle(zone)),
entry_(Object::Handle(zone)) {}
void VisitClass(const Class& cls) {
if (force_ || cls.id() >= kNumPredefinedCids) {
cls.DisableAllocationStub();
}
}
void VisitFunction(const Function& function) {
function.ClearCode();
function.ClearICDataArray();
}
private:
const bool force_;
ObjectPool& pool_;
Object& entry_;
};
ClearCodeVisitor visitor(zone, including_nonchanging_cids);
ProgramVisitor::WalkProgram(zone, isolate_group, &visitor);
// Apart from normal function code and allocation stubs we have two global
// code objects to clear.
if (including_nonchanging_cids) {
auto object_store = isolate_group->object_store();
auto& null_code = Code::Handle(zone);
object_store->set_build_generic_method_extractor_code(null_code);
object_store->set_build_nongeneric_method_extractor_code(null_code);
}
}
#endif // !defined(DART_PRECOMPILED_RUNTIME)
} // namespace dart
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