v8/src/types.cc

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// Copyright 2014 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 "types.h"
#include "string-stream.h"
#include "types-inl.h"
namespace v8 {
namespace internal {
template<class Config>
int TypeImpl<Config>::NumClasses() {
if (this->IsClass()) {
return 1;
} else if (this->IsUnion()) {
StructHandle unioned = this->AsUnion();
int result = 0;
for (int i = 0; i < Config::struct_length(unioned); ++i) {
if (Config::struct_get(unioned, i)->IsClass()) ++result;
}
return result;
} else {
return 0;
}
}
template<class Config>
int TypeImpl<Config>::NumConstants() {
if (this->IsConstant()) {
return 1;
} else if (this->IsUnion()) {
StructHandle unioned = this->AsUnion();
int result = 0;
for (int i = 0; i < Config::struct_length(unioned); ++i) {
if (Config::struct_get(unioned, i)->IsConstant()) ++result;
}
return result;
} else {
return 0;
}
}
template<class Config> template<class T>
typename TypeImpl<Config>::TypeHandle
TypeImpl<Config>::Iterator<T>::get_type() {
ASSERT(!Done());
return type_->IsUnion()
? Config::struct_get(type_->AsUnion(), index_) : type_;
}
// C++ cannot specialise nested templates, so we have to go through this
// contortion with an auxiliary template to simulate it.
template<class Config, class T>
struct TypeImplIteratorAux {
static bool matches(typename TypeImpl<Config>::TypeHandle type);
static i::Handle<T> current(typename TypeImpl<Config>::TypeHandle type);
};
template<class Config>
struct TypeImplIteratorAux<Config, i::Map> {
static bool matches(typename TypeImpl<Config>::TypeHandle type) {
return type->IsClass();
}
static i::Handle<i::Map> current(typename TypeImpl<Config>::TypeHandle type) {
return type->AsClass();
}
};
template<class Config>
struct TypeImplIteratorAux<Config, i::Object> {
static bool matches(typename TypeImpl<Config>::TypeHandle type) {
return type->IsConstant();
}
static i::Handle<i::Object> current(
typename TypeImpl<Config>::TypeHandle type) {
return type->AsConstant();
}
};
template<class Config> template<class T>
bool TypeImpl<Config>::Iterator<T>::matches(TypeHandle type) {
return TypeImplIteratorAux<Config, T>::matches(type);
}
template<class Config> template<class T>
i::Handle<T> TypeImpl<Config>::Iterator<T>::Current() {
return TypeImplIteratorAux<Config, T>::current(get_type());
}
template<class Config> template<class T>
void TypeImpl<Config>::Iterator<T>::Advance() {
++index_;
if (type_->IsUnion()) {
StructHandle unioned = type_->AsUnion();
for (; index_ < Config::struct_length(unioned); ++index_) {
if (matches(Config::struct_get(unioned, index_))) return;
}
} else if (index_ == 0 && matches(type_)) {
return;
}
index_ = -1;
}
// Get the smallest bitset subsuming this type.
template<class Config>
int TypeImpl<Config>::LubBitset() {
if (this->IsBitset()) {
return this->AsBitset();
} else if (this->IsUnion()) {
StructHandle unioned = this->AsUnion();
int bitset = kNone;
for (int i = 0; i < Config::struct_length(unioned); ++i) {
bitset |= Config::struct_get(unioned, i)->LubBitset();
}
return bitset;
} else if (this->IsClass()) {
int bitset = Config::lub_bitset(this);
return bitset ? bitset : LubBitset(*this->AsClass());
} else {
int bitset = Config::lub_bitset(this);
return bitset ? bitset : LubBitset(*this->AsConstant());
}
}
template<class Config>
int TypeImpl<Config>::LubBitset(i::Object* value) {
if (value->IsSmi()) return kSignedSmall & kTaggedInt;
i::Map* map = i::HeapObject::cast(value)->map();
if (map->instance_type() == HEAP_NUMBER_TYPE) {
int32_t i;
uint32_t u;
return kTaggedPtr & (
value->ToInt32(&i) ? (Smi::IsValid(i) ? kSignedSmall : kOtherSigned32) :
value->ToUint32(&u) ? kUnsigned32 : kFloat);
}
return LubBitset(map);
}
template<class Config>
int TypeImpl<Config>::LubBitset(i::Map* map) {
switch (map->instance_type()) {
case STRING_TYPE:
case ASCII_STRING_TYPE:
case CONS_STRING_TYPE:
case CONS_ASCII_STRING_TYPE:
case SLICED_STRING_TYPE:
case SLICED_ASCII_STRING_TYPE:
case EXTERNAL_STRING_TYPE:
case EXTERNAL_ASCII_STRING_TYPE:
case EXTERNAL_STRING_WITH_ONE_BYTE_DATA_TYPE:
case SHORT_EXTERNAL_STRING_TYPE:
case SHORT_EXTERNAL_ASCII_STRING_TYPE:
case SHORT_EXTERNAL_STRING_WITH_ONE_BYTE_DATA_TYPE:
case INTERNALIZED_STRING_TYPE:
case ASCII_INTERNALIZED_STRING_TYPE:
case EXTERNAL_INTERNALIZED_STRING_TYPE:
case EXTERNAL_ASCII_INTERNALIZED_STRING_TYPE:
case EXTERNAL_INTERNALIZED_STRING_WITH_ONE_BYTE_DATA_TYPE:
case SHORT_EXTERNAL_INTERNALIZED_STRING_TYPE:
case SHORT_EXTERNAL_ASCII_INTERNALIZED_STRING_TYPE:
case SHORT_EXTERNAL_INTERNALIZED_STRING_WITH_ONE_BYTE_DATA_TYPE:
return kString;
case SYMBOL_TYPE:
return kSymbol;
case ODDBALL_TYPE: {
Heap* heap = map->GetHeap();
if (map == heap->undefined_map()) return kUndefined;
if (map == heap->the_hole_map()) return kAny; // TODO(rossberg): kNone?
if (map == heap->null_map()) return kNull;
if (map == heap->boolean_map()) return kBoolean;
ASSERT(map == heap->uninitialized_map() ||
map == heap->no_interceptor_result_sentinel_map() ||
map == heap->termination_exception_map() ||
map == heap->arguments_marker_map());
return kInternal & kTaggedPtr;
}
case HEAP_NUMBER_TYPE:
return kFloat & kTaggedPtr;
case JS_VALUE_TYPE:
case JS_DATE_TYPE:
case JS_OBJECT_TYPE:
case JS_CONTEXT_EXTENSION_OBJECT_TYPE:
case JS_GENERATOR_OBJECT_TYPE:
case JS_MODULE_TYPE:
case JS_GLOBAL_OBJECT_TYPE:
case JS_BUILTINS_OBJECT_TYPE:
case JS_GLOBAL_PROXY_TYPE:
case JS_ARRAY_BUFFER_TYPE:
case JS_TYPED_ARRAY_TYPE:
case JS_DATA_VIEW_TYPE:
case JS_SET_TYPE:
case JS_MAP_TYPE:
case JS_WEAK_MAP_TYPE:
case JS_WEAK_SET_TYPE:
if (map->is_undetectable()) return kUndetectable;
return kOtherObject;
case JS_ARRAY_TYPE:
return kArray;
case JS_FUNCTION_TYPE:
return kFunction;
case JS_REGEXP_TYPE:
return kRegExp;
case JS_PROXY_TYPE:
case JS_FUNCTION_PROXY_TYPE:
return kProxy;
case MAP_TYPE:
// When compiling stub templates, the meta map is used as a place holder
// for the actual map with which the template is later instantiated.
// We treat it as a kind of type variable whose upper bound is Any.
// TODO(rossberg): for caching of CompareNilIC stubs to work correctly,
// we must exclude Undetectable here. This makes no sense, really,
// because it means that the template isn't actually parametric.
// Also, it doesn't apply elsewhere. 8-(
// We ought to find a cleaner solution for compiling stubs parameterised
// over type or class variables, esp ones with bounds...
return kDetectable;
case DECLARED_ACCESSOR_INFO_TYPE:
case EXECUTABLE_ACCESSOR_INFO_TYPE:
case ACCESSOR_PAIR_TYPE:
case FIXED_ARRAY_TYPE:
return kInternal & kTaggedPtr;
default:
UNREACHABLE();
return kNone;
}
}
// Get the largest bitset subsumed by this type.
template<class Config>
int TypeImpl<Config>::GlbBitset() {
if (this->IsBitset()) {
return this->AsBitset();
} else if (this->IsUnion()) {
// All but the first are non-bitsets and thus would yield kNone anyway.
return Config::struct_get(this->AsUnion(), 0)->GlbBitset();
} else {
return kNone;
}
}
// Most precise _current_ type of a value (usually its class).
template<class Config>
typename TypeImpl<Config>::TypeHandle TypeImpl<Config>::NowOf(
i::Object* value, Region* region) {
if (value->IsSmi() ||
i::HeapObject::cast(value)->map()->instance_type() == HEAP_NUMBER_TYPE) {
return Of(value, region);
}
return Class(i::handle(i::HeapObject::cast(value)->map()), region);
}
// Check this <= that.
template<class Config>
bool TypeImpl<Config>::SlowIs(TypeImpl* that) {
// Fast path for bitsets.
if (this->IsNone()) return true;
if (that->IsBitset()) {
return (this->LubBitset() | that->AsBitset()) == that->AsBitset();
}
if (that->IsClass()) {
return this->IsClass() && *this->AsClass() == *that->AsClass();
}
if (that->IsConstant()) {
return this->IsConstant() && *this->AsConstant() == *that->AsConstant();
}
// (T1 \/ ... \/ Tn) <= T <=> (T1 <= T) /\ ... /\ (Tn <= T)
if (this->IsUnion()) {
StructHandle unioned = this->AsUnion();
for (int i = 0; i < Config::struct_length(unioned); ++i) {
TypeHandle this_i = Config::struct_get(unioned, i);
if (!this_i->Is(that)) return false;
}
return true;
}
// T <= (T1 \/ ... \/ Tn) <=> (T <= T1) \/ ... \/ (T <= Tn)
// (iff T is not a union)
ASSERT(!this->IsUnion());
if (that->IsUnion()) {
StructHandle unioned = that->AsUnion();
for (int i = 0; i < Config::struct_length(unioned); ++i) {
TypeHandle that_i = Config::struct_get(unioned, i);
if (this->Is(that_i)) return true;
if (this->IsBitset()) break; // Fast fail, only first field is a bitset.
}
return false;
}
return false;
}
template<class Config>
bool TypeImpl<Config>::NowIs(TypeImpl* that) {
DisallowHeapAllocation no_allocation;
if (this->IsConstant()) {
i::Object* object = *this->AsConstant();
if (object->IsHeapObject()) {
i::Map* map = i::HeapObject::cast(object)->map();
for (Iterator<i::Map> it = that->Classes(); !it.Done(); it.Advance()) {
if (*it.Current() == map) return true;
}
}
}
return this->Is(that);
}
// Check this overlaps that.
template<class Config>
bool TypeImpl<Config>::Maybe(TypeImpl* that) {
// (T1 \/ ... \/ Tn) overlaps T <=> (T1 overlaps T) \/ ... \/ (Tn overlaps T)
if (this->IsUnion()) {
StructHandle unioned = this->AsUnion();
for (int i = 0; i < Config::struct_length(unioned); ++i) {
TypeHandle this_i = Config::struct_get(unioned, i);
if (this_i->Maybe(that)) return true;
}
return false;
}
// T overlaps (T1 \/ ... \/ Tn) <=> (T overlaps T1) \/ ... \/ (T overlaps Tn)
if (that->IsUnion()) {
StructHandle unioned = that->AsUnion();
for (int i = 0; i < Config::struct_length(unioned); ++i) {
TypeHandle that_i = Config::struct_get(unioned, i);
if (this->Maybe(that_i)) return true;
}
return false;
}
ASSERT(!this->IsUnion() && !that->IsUnion());
if (this->IsBitset()) {
return IsInhabited(this->AsBitset() & that->LubBitset());
}
if (that->IsBitset()) {
return IsInhabited(this->LubBitset() & that->AsBitset());
}
if (this->IsClass()) {
return that->IsClass() && *this->AsClass() == *that->AsClass();
}
if (this->IsConstant()) {
return that->IsConstant() && *this->AsConstant() == *that->AsConstant();
}
return false;
}
template<class Config>
bool TypeImpl<Config>::Contains(i::Object* value) {
for (Iterator<i::Object> it = this->Constants(); !it.Done(); it.Advance()) {
if (*it.Current() == value) return true;
}
return Config::from_bitset(LubBitset(value))->Is(this);
}
template<class Config>
bool TypeImpl<Config>::InUnion(StructHandle unioned, int current_size) {
ASSERT(!this->IsUnion());
for (int i = 0; i < current_size; ++i) {
TypeHandle type = Config::struct_get(unioned, i);
if (this->Is(type)) return true;
}
return false;
}
// Get non-bitsets from this which are not subsumed by union, store at result,
// starting at index. Returns updated index.
template<class Config>
int TypeImpl<Config>::ExtendUnion(
StructHandle result, TypeHandle type, int current_size) {
int old_size = current_size;
if (type->IsClass() || type->IsConstant()) {
if (!type->InUnion(result, old_size)) {
Config::struct_set(result, current_size++, type);
}
} else if (type->IsUnion()) {
StructHandle unioned = type->AsUnion();
for (int i = 0; i < Config::struct_length(unioned); ++i) {
TypeHandle type = Config::struct_get(unioned, i);
ASSERT(i == 0 ||
!(type->IsBitset() || type->Is(Config::struct_get(unioned, 0))));
if (!type->IsBitset() && !type->InUnion(result, old_size)) {
Config::struct_set(result, current_size++, type);
}
}
}
return current_size;
}
// Union is O(1) on simple bit unions, but O(n*m) on structured unions.
template<class Config>
typename TypeImpl<Config>::TypeHandle TypeImpl<Config>::Union(
TypeHandle type1, TypeHandle type2, Region* region) {
// Fast case: bit sets.
if (type1->IsBitset() && type2->IsBitset()) {
return Config::from_bitset(type1->AsBitset() | type2->AsBitset(), region);
}
// Fast case: top or bottom types.
if (type1->IsAny() || type2->IsNone()) return type1;
if (type2->IsAny() || type1->IsNone()) return type2;
// Semi-fast case: Unioned objects are neither involved nor produced.
if (!(type1->IsUnion() || type2->IsUnion())) {
if (type1->Is(type2)) return type2;
if (type2->Is(type1)) return type1;
}
// Slow case: may need to produce a Unioned object.
int size = 0;
if (!type1->IsBitset()) {
size += (type1->IsUnion() ? Config::struct_length(type1->AsUnion()) : 1);
}
if (!type2->IsBitset()) {
size += (type2->IsUnion() ? Config::struct_length(type2->AsUnion()) : 1);
}
int bitset = type1->GlbBitset() | type2->GlbBitset();
if (IsInhabited(bitset)) ++size;
ASSERT(size >= 1);
StructHandle unioned = Config::struct_create(kUnionTag, size, region);
size = 0;
if (IsInhabited(bitset)) {
Config::struct_set(unioned, size++, Config::from_bitset(bitset, region));
}
size = ExtendUnion(unioned, type1, size);
size = ExtendUnion(unioned, type2, size);
if (size == 1) {
return Config::struct_get(unioned, 0);
} else {
Config::struct_shrink(unioned, size);
return Config::from_struct(unioned);
}
}
// Get non-bitsets from type which are also in other, store at result,
// starting at index. Returns updated index.
template<class Config>
int TypeImpl<Config>::ExtendIntersection(
StructHandle result, TypeHandle type, TypeHandle other, int current_size) {
int old_size = current_size;
if (type->IsClass() || type->IsConstant()) {
if (type->Is(other) && !type->InUnion(result, old_size)) {
Config::struct_set(result, current_size++, type);
}
} else if (type->IsUnion()) {
StructHandle unioned = type->AsUnion();
for (int i = 0; i < Config::struct_length(unioned); ++i) {
TypeHandle type = Config::struct_get(unioned, i);
ASSERT(i == 0 ||
!(type->IsBitset() || type->Is(Config::struct_get(unioned, 0))));
if (!type->IsBitset() && type->Is(other) &&
!type->InUnion(result, old_size)) {
Config::struct_set(result, current_size++, type);
}
}
}
return current_size;
}
// Intersection is O(1) on simple bit unions, but O(n*m) on structured unions.
// TODO(rossberg): Should we use object sets somehow? Is it worth it?
template<class Config>
typename TypeImpl<Config>::TypeHandle TypeImpl<Config>::Intersect(
TypeHandle type1, TypeHandle type2, Region* region) {
// Fast case: bit sets.
if (type1->IsBitset() && type2->IsBitset()) {
return Config::from_bitset(type1->AsBitset() & type2->AsBitset(), region);
}
// Fast case: top or bottom types.
if (type1->IsNone() || type2->IsAny()) return type1;
if (type2->IsNone() || type1->IsAny()) return type2;
// Semi-fast case: Unioned objects are neither involved nor produced.
if (!(type1->IsUnion() || type2->IsUnion())) {
if (type1->Is(type2)) return type1;
if (type2->Is(type1)) return type2;
}
// Slow case: may need to produce a Unioned object.
int size = INT_MAX;
if (!type1->IsBitset()) {
size = (type1->IsUnion() ? Config::struct_length(type1->AsUnion()) : 1);
}
if (!type2->IsBitset()) {
size = Min(size,
type2->IsUnion() ? Config::struct_length(type2->AsUnion()) : 1);
}
int bitset = type1->GlbBitset() & type2->GlbBitset();
if (IsInhabited(bitset)) ++size;
ASSERT(size >= 1);
StructHandle unioned = Config::struct_create(kUnionTag, size, region);
size = 0;
if (IsInhabited(bitset)) {
Config::struct_set(unioned, size++, Config::from_bitset(bitset, region));
}
size = ExtendIntersection(unioned, type1, type2, size);
size = ExtendIntersection(unioned, type2, type1, size);
if (size == 0) {
return None(region);
} else if (size == 1) {
return Config::struct_get(unioned, 0);
} else {
Config::struct_shrink(unioned, size);
return Config::from_struct(unioned);
}
}
template<class Config>
template<class OtherType>
typename TypeImpl<Config>::TypeHandle TypeImpl<Config>::Convert(
typename OtherType::TypeHandle type, Region* region) {
if (type->IsBitset()) {
return Config::from_bitset(type->AsBitset(), region);
} else if (type->IsClass()) {
return Config::from_class(type->AsClass(), type->LubBitset(), region);
} else if (type->IsConstant()) {
return Config::from_constant(type->AsConstant(), type->LubBitset(), region);
} else {
ASSERT(type->IsUnion());
typename OtherType::StructHandle unioned = type->AsUnion();
int length = OtherType::StructLength(unioned);
StructHandle new_unioned = Config::struct_create(kUnionTag, length, region);
for (int i = 0; i < length; ++i) {
Config::struct_set(new_unioned, i,
Convert<OtherType>(OtherType::StructGet(unioned, i), region));
}
return Config::from_struct(new_unioned);
}
}
// TODO(rossberg): this does not belong here.
Representation Representation::FromType(Type* type) {
if (type->Is(Type::None())) return Representation::None();
if (type->Is(Type::SignedSmall())) return Representation::Smi();
if (type->Is(Type::Signed32())) return Representation::Integer32();
if (type->Is(Type::Number())) return Representation::Double();
return Representation::Tagged();
}
template<class Config>
void TypeImpl<Config>::TypePrint(PrintDimension dim) {
TypePrint(stdout, dim);
PrintF(stdout, "\n");
Flush(stdout);
}
template<class Config>
const char* TypeImpl<Config>::bitset_name(int bitset) {
switch (bitset) {
case kAny & kRepresentation: return "Any";
#define PRINT_COMPOSED_TYPE(type, value) \
case k##type & kRepresentation: return #type;
REPRESENTATION_BITSET_TYPE_LIST(PRINT_COMPOSED_TYPE)
#undef PRINT_COMPOSED_TYPE
#define PRINT_COMPOSED_TYPE(type, value) \
case k##type & kSemantic: return #type;
SEMANTIC_BITSET_TYPE_LIST(PRINT_COMPOSED_TYPE)
#undef PRINT_COMPOSED_TYPE
default:
return NULL;
}
}
template<class Config>
void TypeImpl<Config>::BitsetTypePrint(FILE* out, int bitset) {
const char* name = bitset_name(bitset);
if (name != NULL) {
PrintF(out, "%s", name);
} else {
static const int named_bitsets[] = {
#define BITSET_CONSTANT(type, value) k##type & kRepresentation,
REPRESENTATION_BITSET_TYPE_LIST(BITSET_CONSTANT)
#undef BITSET_CONSTANT
#define BITSET_CONSTANT(type, value) k##type & kSemantic,
SEMANTIC_BITSET_TYPE_LIST(BITSET_CONSTANT)
#undef BITSET_CONSTANT
};
bool is_first = true;
PrintF(out, "(");
for (int i(ARRAY_SIZE(named_bitsets) - 1); bitset != 0 && i >= 0; --i) {
int subset = named_bitsets[i];
if ((bitset & subset) == subset) {
if (!is_first) PrintF(out, " | ");
is_first = false;
PrintF(out, "%s", bitset_name(subset));
bitset -= subset;
}
}
ASSERT(bitset == 0);
PrintF(out, ")");
}
}
template<class Config>
void TypeImpl<Config>::TypePrint(FILE* out, PrintDimension dim) {
if (this->IsBitset()) {
int bitset = this->AsBitset();
switch (dim) {
case BOTH_DIMS:
BitsetTypePrint(out, bitset & kSemantic);
PrintF(out, "/");
BitsetTypePrint(out, bitset & kRepresentation);
break;
case SEMANTIC_DIM:
BitsetTypePrint(out, bitset & kSemantic);
break;
case REPRESENTATION_DIM:
BitsetTypePrint(out, bitset & kRepresentation);
break;
}
} else if (this->IsConstant()) {
PrintF(out, "Constant(%p : ", static_cast<void*>(*this->AsConstant()));
Config::from_bitset(this->LubBitset())->TypePrint(out, dim);
PrintF(out, ")");
} else if (this->IsClass()) {
PrintF(out, "Class(%p < ", static_cast<void*>(*this->AsClass()));
Config::from_bitset(this->LubBitset())->TypePrint(out, dim);
PrintF(out, ")");
} else if (this->IsUnion()) {
PrintF(out, "(");
StructHandle unioned = this->AsUnion();
for (int i = 0; i < Config::struct_length(unioned); ++i) {
TypeHandle type_i = Config::struct_get(unioned, i);
if (i > 0) PrintF(out, " | ");
type_i->TypePrint(out, dim);
}
PrintF(out, ")");
}
}
template class TypeImpl<ZoneTypeConfig>;
template class TypeImpl<ZoneTypeConfig>::Iterator<i::Map>;
template class TypeImpl<ZoneTypeConfig>::Iterator<i::Object>;
template class TypeImpl<HeapTypeConfig>;
template class TypeImpl<HeapTypeConfig>::Iterator<i::Map>;
template class TypeImpl<HeapTypeConfig>::Iterator<i::Object>;
template TypeImpl<ZoneTypeConfig>::TypeHandle
TypeImpl<ZoneTypeConfig>::Convert<HeapType>(
TypeImpl<HeapTypeConfig>::TypeHandle, TypeImpl<ZoneTypeConfig>::Region*);
template TypeImpl<HeapTypeConfig>::TypeHandle
TypeImpl<HeapTypeConfig>::Convert<Type>(
TypeImpl<ZoneTypeConfig>::TypeHandle, TypeImpl<HeapTypeConfig>::Region*);
} } // namespace v8::internal