v8/src/types.cc

539 lines
17 KiB
C++

// Copyright 2013 the V8 project authors. All rights reserved.
// Redistribution and use in source and binary forms, with or without
// modification, are permitted provided that the following conditions are
// met:
//
// * Redistributions of source code must retain the above copyright
// notice, this list of conditions and the following disclaimer.
// * Redistributions in binary form must reproduce the above
// copyright notice, this list of conditions and the following
// disclaimer in the documentation and/or other materials provided
// with the distribution.
// * Neither the name of Google Inc. nor the names of its
// contributors may be used to endorse or promote products derived
// from this software without specific prior written permission.
//
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
#include "types.h"
#include "string-stream.h"
namespace v8 {
namespace internal {
int Type::NumClasses() {
if (is_class()) {
return 1;
} else if (is_union()) {
Handle<Unioned> unioned = as_union();
int result = 0;
for (int i = 0; i < unioned->length(); ++i) {
if (union_get(unioned, i)->is_class()) ++result;
}
return result;
} else {
return 0;
}
}
int Type::NumConstants() {
if (is_constant()) {
return 1;
} else if (is_union()) {
Handle<Unioned> unioned = as_union();
int result = 0;
for (int i = 0; i < unioned->length(); ++i) {
if (union_get(unioned, i)->is_constant()) ++result;
}
return result;
} else {
return 0;
}
}
template<class T>
Handle<Type> Type::Iterator<T>::get_type() {
ASSERT(!Done());
return type_->is_union() ? union_get(type_->as_union(), index_) : type_;
}
template<>
Handle<Map> Type::Iterator<Map>::Current() {
return get_type()->as_class();
}
template<>
Handle<v8::internal::Object> Type::Iterator<v8::internal::Object>::Current() {
return get_type()->as_constant();
}
template<>
bool Type::Iterator<Map>::matches(Handle<Type> type) {
return type->is_class();
}
template<>
bool Type::Iterator<v8::internal::Object>::matches(Handle<Type> type) {
return type->is_constant();
}
template<class T>
void Type::Iterator<T>::Advance() {
++index_;
if (type_->is_union()) {
Handle<Unioned> unioned = type_->as_union();
for (; index_ < unioned->length(); ++index_) {
if (matches(union_get(unioned, index_))) return;
}
} else if (index_ == 0 && matches(type_)) {
return;
}
index_ = -1;
}
template class Type::Iterator<Map>;
template class Type::Iterator<v8::internal::Object>;
// Get the smallest bitset subsuming this type.
int Type::LubBitset() {
if (this->is_bitset()) {
return this->as_bitset();
} else if (this->is_union()) {
Handle<Unioned> unioned = this->as_union();
int bitset = kNone;
for (int i = 0; i < unioned->length(); ++i) {
bitset |= union_get(unioned, i)->LubBitset();
}
return bitset;
} else {
Map* map = NULL;
if (this->is_class()) {
map = *this->as_class();
} else {
Handle<v8::internal::Object> value = this->as_constant();
if (value->IsSmi()) return kSmi;
map = HeapObject::cast(*value)->map();
if (map->instance_type() == ODDBALL_TYPE) {
if (value->IsUndefined()) return kUndefined;
if (value->IsNull()) return kNull;
if (value->IsTrue() || value->IsFalse()) return kBoolean;
if (value->IsTheHole()) return kAny;
}
}
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 CONS_INTERNALIZED_STRING_TYPE:
case CONS_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:
return kOddball;
case HEAP_NUMBER_TYPE:
return kDouble;
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;
default:
UNREACHABLE();
return kNone;
}
}
}
// Get the largest bitset subsumed by this type.
int Type::GlbBitset() {
if (this->is_bitset()) {
return this->as_bitset();
} else if (this->is_union()) {
// All but the first are non-bitsets and thus would yield kNone anyway.
return union_get(this->as_union(), 0)->GlbBitset();
} else {
return kNone;
}
}
// Check this <= that.
bool Type::IsSlowCase(Type* that) {
// Fast path for bitsets.
if (that->is_bitset()) {
return (this->LubBitset() | that->as_bitset()) == that->as_bitset();
}
if (that->is_class()) {
return this->is_class() && *this->as_class() == *that->as_class();
}
if (that->is_constant()) {
return this->is_constant() && *this->as_constant() == *that->as_constant();
}
// (T1 \/ ... \/ Tn) <= T <=> (T1 <= T) /\ ... /\ (Tn <= T)
if (this->is_union()) {
Handle<Unioned> unioned = this->as_union();
for (int i = 0; i < unioned->length(); ++i) {
Handle<Type> this_i = union_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->is_union());
if (that->is_union()) {
Handle<Unioned> unioned = that->as_union();
for (int i = 0; i < unioned->length(); ++i) {
Handle<Type> that_i = union_get(unioned, i);
if (this->Is(that_i)) return true;
if (this->is_bitset()) break; // Fast fail, no other field is a bitset.
}
return false;
}
return false;
}
// Check this overlaps that.
bool Type::Maybe(Type* that) {
// Fast path for bitsets.
if (this->is_bitset()) {
return (this->as_bitset() & that->LubBitset()) != 0;
}
if (that->is_bitset()) {
return (this->LubBitset() & that->as_bitset()) != 0;
}
// (T1 \/ ... \/ Tn) overlaps T <=> (T1 overlaps T) \/ ... \/ (Tn overlaps T)
if (this->is_union()) {
Handle<Unioned> unioned = this->as_union();
for (int i = 0; i < unioned->length(); ++i) {
Handle<Type> this_i = union_get(unioned, i);
if (this_i->Maybe(that)) return true;
}
return false;
}
// T overlaps (T1 \/ ... \/ Tn) <=> (T overlaps T1) \/ ... \/ (T overlaps Tn)
if (that->is_union()) {
Handle<Unioned> unioned = that->as_union();
for (int i = 0; i < unioned->length(); ++i) {
Handle<Type> that_i = union_get(unioned, i);
if (this->Maybe(that_i)) return true;
}
return false;
}
ASSERT(!that->is_union());
if (this->is_class()) {
return that->is_class() && *this->as_class() == *that->as_class();
}
if (this->is_constant()) {
return that->is_constant() && *this->as_constant() == *that->as_constant();
}
return false;
}
bool Type::InUnion(Handle<Unioned> unioned, int current_size) {
ASSERT(!this->is_union());
for (int i = 0; i < current_size; ++i) {
Handle<Type> type = union_get(unioned, i);
if (this->Is(type)) return true;
}
return false;
}
// Get non-bitsets from this which are not subsumed by union, store at unioned,
// starting at index. Returns updated index.
int Type::ExtendUnion(Handle<Unioned> result, int current_size) {
int old_size = current_size;
if (this->is_class() || this->is_constant()) {
if (!this->InUnion(result, old_size)) result->set(current_size++, this);
} else if (this->is_union()) {
Handle<Unioned> unioned = this->as_union();
for (int i = 0; i < unioned->length(); ++i) {
Handle<Type> type = union_get(unioned, i);
ASSERT(i == 0 || !(type->is_bitset() || type->Is(union_get(unioned, 0))));
if (type->is_bitset()) continue;
if (!type->InUnion(result, old_size)) result->set(current_size++, *type);
}
}
return current_size;
}
// Union 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?
Type* Type::Union(Handle<Type> type1, Handle<Type> type2) {
// Fast case: bit sets.
if (type1->is_bitset() && type2->is_bitset()) {
return from_bitset(type1->as_bitset() | type2->as_bitset());
}
// Fast case: top or bottom types.
if (type1->SameValue(Type::Any())) return *type1;
if (type2->SameValue(Type::Any())) return *type2;
if (type1->SameValue(Type::None())) return *type2;
if (type2->SameValue(Type::None())) return *type1;
// Semi-fast case: Unioned objects are neither involved nor produced.
if (!(type1->is_union() || type2->is_union())) {
if (type1->Is(type2)) return *type2;
if (type2->Is(type1)) return *type1;
}
// Slow case: may need to produce a Unioned object.
Isolate* isolate = NULL;
int size = type1->is_bitset() || type2->is_bitset() ? 1 : 0;
if (!type1->is_bitset()) {
isolate = HeapObject::cast(*type1)->GetIsolate();
size += (type1->is_union() ? type1->as_union()->length() : 1);
}
if (!type2->is_bitset()) {
isolate = HeapObject::cast(*type2)->GetIsolate();
size += (type2->is_union() ? type2->as_union()->length() : 1);
}
ASSERT(isolate != NULL);
ASSERT(size >= 2);
Handle<Unioned> unioned = isolate->factory()->NewFixedArray(size);
size = 0;
int bitset = type1->GlbBitset() | type2->GlbBitset();
if (bitset != kNone) unioned->set(size++, from_bitset(bitset));
size = type1->ExtendUnion(unioned, size);
size = type2->ExtendUnion(unioned, size);
if (size == 1) {
return *union_get(unioned, 0);
} else if (size == unioned->length()) {
return from_handle(unioned);
}
// There was an overlap. Copy to smaller union.
Handle<Unioned> result = isolate->factory()->NewFixedArray(size);
for (int i = 0; i < size; ++i) result->set(i, unioned->get(i));
return from_handle(result);
}
// Get non-bitsets from this which are also in that, store at unioned,
// starting at index. Returns updated index.
int Type::ExtendIntersection(
Handle<Unioned> result, Handle<Type> that, int current_size) {
int old_size = current_size;
if (this->is_class() || this->is_constant()) {
if (this->Is(that) && !this->InUnion(result, old_size))
result->set(current_size++, this);
} else if (this->is_union()) {
Handle<Unioned> unioned = this->as_union();
for (int i = 0; i < unioned->length(); ++i) {
Handle<Type> type = union_get(unioned, i);
ASSERT(i == 0 || !(type->is_bitset() || type->Is(union_get(unioned, 0))));
if (type->is_bitset()) continue;
if (type->Is(that) && !type->InUnion(result, old_size))
result->set(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?
Type* Type::Intersect(Handle<Type> type1, Handle<Type> type2) {
// Fast case: bit sets.
if (type1->is_bitset() && type2->is_bitset()) {
return from_bitset(type1->as_bitset() & type2->as_bitset());
}
// Fast case: top or bottom types.
if (type1->SameValue(Type::None())) return *type1;
if (type2->SameValue(Type::None())) return *type2;
if (type1->SameValue(Type::Any())) return *type2;
if (type2->SameValue(Type::Any())) return *type1;
// Semi-fast case: Unioned objects are neither involved nor produced.
if (!(type1->is_union() || type2->is_union())) {
if (type1->Is(type2)) return *type1;
if (type2->Is(type1)) return *type2;
}
// Slow case: may need to produce a Unioned object.
Isolate* isolate = NULL;
int size = 0;
if (!type1->is_bitset()) {
isolate = HeapObject::cast(*type1)->GetIsolate();
size = (type1->is_union() ? type1->as_union()->length() : 2);
}
if (!type2->is_bitset()) {
isolate = HeapObject::cast(*type2)->GetIsolate();
int size2 = (type2->is_union() ? type2->as_union()->length() : 2);
size = (size == 0 ? size2 : Min(size, size2));
}
ASSERT(isolate != NULL);
ASSERT(size >= 2);
Handle<Unioned> unioned = isolate->factory()->NewFixedArray(size);
size = 0;
int bitset = type1->GlbBitset() & type2->GlbBitset();
if (bitset != kNone) unioned->set(size++, from_bitset(bitset));
size = type1->ExtendIntersection(unioned, type2, size);
size = type2->ExtendIntersection(unioned, type1, size);
if (size == 0) {
return None();
} else if (size == 1) {
return *union_get(unioned, 0);
} else if (size == unioned->length()) {
return from_handle(unioned);
}
// There were dropped cases. Copy to smaller union.
Handle<Unioned> result = isolate->factory()->NewFixedArray(size);
for (int i = 0; i < size; ++i) result->set(i, unioned->get(i));
return from_handle(result);
}
Type* Type::Optional(Handle<Type> type) {
return type->is_bitset()
? from_bitset(type->as_bitset() | kUndefined)
: Union(type, Undefined()->handle_via_isolate_of(*type));
}
Representation Representation::FromType(Handle<Type> type) {
if (type->Is(Type::None())) return Representation::None();
if (type->Is(Type::Smi())) return Representation::Smi();
if (type->Is(Type::Signed32())) return Representation::Integer32();
if (type->Is(Type::Number())) return Representation::Double();
return Representation::Tagged();
}
#ifdef OBJECT_PRINT
void Type::TypePrint() {
TypePrint(stdout);
PrintF(stdout, "\n");
Flush(stdout);
}
void Type::TypePrint(FILE* out) {
if (is_bitset()) {
int val = as_bitset();
const char* composed_name = GetComposedName(val);
if (composed_name != NULL) {
PrintF(out, "%s", composed_name);
return;
}
bool first_entry = true;
PrintF(out, "{");
for (unsigned i = 0; i < sizeof(val)*8; ++i) {
int mask = (1 << i);
if ((val & mask) != 0) {
if (!first_entry) PrintF(out, ",");
first_entry = false;
PrintF(out, "%s", GetPrimitiveName(mask));
}
}
PrintF(out, "}");
} else if (is_constant()) {
PrintF(out, "Constant(%p)", static_cast<void*>(*as_constant()));
} else if (is_class()) {
PrintF(out, "Class(%p)", static_cast<void*>(*as_class()));
} else if (is_union()) {
PrintF(out, "{");
Handle<Unioned> unioned = as_union();
for (int i = 0; i < unioned->length(); ++i) {
Handle<Type> type_i = union_get(unioned, i);
if (i > 0) PrintF(out, ",");
type_i->TypePrint(out);
}
PrintF(out, "}");
}
}
#endif
} } // namespace v8::internal