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v8/src/types.h
jarin@chromium.org c7685a59f0 [turbofan] Use range types to type and lower arithmetic ops. 
This is based on Georg's work on typing arithmetic operations (https://codereview.chromium.org/658743002/).

Instead of weakening to bitset types, we weaken to the closest 2^n
limit if we see that we are re-typing a node with a range type (which
means that the node can be part of a cycle, so we might need
to speed up the fixpoint there).

BUG=
R=rossberg@chromium.org

Review URL: https://codereview.chromium.org/636283009

git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@24848 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
2014-10-23 14:40:43 +00:00

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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.
#ifndef V8_TYPES_H_
#define V8_TYPES_H_
#include "src/conversions.h"
#include "src/factory.h"
#include "src/handles.h"
#include "src/ostreams.h"
namespace v8 {
namespace internal {
// SUMMARY
//
// A simple type system for compiler-internal use. It is based entirely on
// union types, and all subtyping hence amounts to set inclusion. Besides the
// obvious primitive types and some predefined unions, the type language also
// can express class types (a.k.a. specific maps) and singleton types (i.e.,
// concrete constants).
//
// Types consist of two dimensions: semantic (value range) and representation.
// Both are related through subtyping.
//
//
// SEMANTIC DIMENSION
//
// The following equations and inequations hold for the semantic axis:
//
// None <= T
// T <= Any
//
// Number = Signed32 \/ Unsigned32 \/ Double
// Smi <= Signed32
// Name = String \/ Symbol
// UniqueName = InternalizedString \/ Symbol
// InternalizedString < String
//
// Receiver = Object \/ Proxy
// Array < Object
// Function < Object
// RegExp < Object
// Undetectable < Object
// Detectable = Receiver \/ Number \/ Name - Undetectable
//
// Class(map) < T iff instance_type(map) < T
// Constant(x) < T iff instance_type(map(x)) < T
// Array(T) < Array
// Function(R, S, T0, T1, ...) < Function
// Context(T) < Internal
//
// Both structural Array and Function types are invariant in all parameters;
// relaxing this would make Union and Intersect operations more involved.
// There is no subtyping relation between Array, Function, or Context types
// and respective Constant types, since these types cannot be reconstructed
// for arbitrary heap values.
// Note also that Constant(x) < Class(map(x)) does _not_ hold, since x's map can
// change! (Its instance type cannot, however.)
// TODO(rossberg): the latter is not currently true for proxies, because of fix,
// but will hold once we implement direct proxies.
// However, we also define a 'temporal' variant of the subtyping relation that
// considers the _current_ state only, i.e., Constant(x) <_now Class(map(x)).
//
//
// REPRESENTATIONAL DIMENSION
//
// For the representation axis, the following holds:
//
// None <= R
// R <= Any
//
// UntaggedInt = UntaggedInt1 \/ UntaggedInt8 \/
// UntaggedInt16 \/ UntaggedInt32
// UntaggedFloat = UntaggedFloat32 \/ UntaggedFloat64
// UntaggedNumber = UntaggedInt \/ UntaggedFloat
// Untagged = UntaggedNumber \/ UntaggedPtr
// Tagged = TaggedInt \/ TaggedPtr
//
// Subtyping relates the two dimensions, for example:
//
// Number <= Tagged \/ UntaggedNumber
// Object <= TaggedPtr \/ UntaggedPtr
//
// That holds because the semantic type constructors defined by the API create
// types that allow for all possible representations, and dually, the ones for
// representation types initially include all semantic ranges. Representations
// can then e.g. be narrowed for a given semantic type using intersection:
//
// SignedSmall /\ TaggedInt (a 'smi')
// Number /\ TaggedPtr (a heap number)
//
//
// RANGE TYPES
//
// A range type represents a continuous integer interval by its minimum and
// maximum value. Either value might be an infinity.
//
// Constant(v) is considered a subtype of Range(x..y) if v happens to be an
// integer between x and y.
//
//
// PREDICATES
//
// There are two main functions for testing types:
//
// T1->Is(T2) -- tests whether T1 is included in T2 (i.e., T1 <= T2)
// T1->Maybe(T2) -- tests whether T1 and T2 overlap (i.e., T1 /\ T2 =/= 0)
//
// Typically, the former is to be used to select representations (e.g., via
// T->Is(SignedSmall())), and the latter to check whether a specific case needs
// handling (e.g., via T->Maybe(Number())).
//
// There is no functionality to discover whether a type is a leaf in the
// lattice. That is intentional. It should always be possible to refine the
// lattice (e.g., splitting up number types further) without invalidating any
// existing assumptions or tests.
// Consequently, do not normally use Equals for type tests, always use Is!
//
// The NowIs operator implements state-sensitive subtying, as described above.
// Any compilation decision based on such temporary properties requires runtime
// guarding!
//
//
// PROPERTIES
//
// Various formal properties hold for constructors, operators, and predicates
// over types. For example, constructors are injective and subtyping is a
// complete partial order.
//
// See test/cctest/test-types.cc for a comprehensive executable specification,
// especially with respect to the properties of the more exotic 'temporal'
// constructors and predicates (those prefixed 'Now').
//
//
// IMPLEMENTATION
//
// Internally, all 'primitive' types, and their unions, are represented as
// bitsets. Bit 0 is reserved for tagging. Class is a heap pointer to the
// respective map. Only structured types require allocation.
// Note that the bitset representation is closed under both Union and Intersect.
//
// There are two type representations, using different allocation:
//
// - class Type (zone-allocated, for compiler and concurrent compilation)
// - class HeapType (heap-allocated, for persistent types)
//
// Both provide the same API, and the Convert method can be used to interconvert
// them. For zone types, no query method touches the heap, only constructors do.
// -----------------------------------------------------------------------------
// Values for bitset types
#define MASK_BITSET_TYPE_LIST(V) \
V(Representation, 0xff800000u) \
V(Semantic, 0x007ffffeu)
#define REPRESENTATION(k) ((k) & BitsetType::kRepresentation)
#define SEMANTIC(k) ((k) & BitsetType::kSemantic)
#define REPRESENTATION_BITSET_TYPE_LIST(V) \
V(None, 0) \
V(UntaggedInt1, 1u << 23 | kSemantic) \
V(UntaggedInt8, 1u << 24 | kSemantic) \
V(UntaggedInt16, 1u << 25 | kSemantic) \
V(UntaggedInt32, 1u << 26 | kSemantic) \
V(UntaggedFloat32, 1u << 27 | kSemantic) \
V(UntaggedFloat64, 1u << 28 | kSemantic) \
V(UntaggedPtr, 1u << 29 | kSemantic) \
V(TaggedInt, 1u << 30 | kSemantic) \
V(TaggedPtr, 1u << 31 | kSemantic) \
\
V(UntaggedInt, kUntaggedInt1 | kUntaggedInt8 | \
kUntaggedInt16 | kUntaggedInt32) \
V(UntaggedFloat, kUntaggedFloat32 | kUntaggedFloat64) \
V(UntaggedNumber, kUntaggedInt | kUntaggedFloat) \
V(Untagged, kUntaggedNumber | kUntaggedPtr) \
V(Tagged, kTaggedInt | kTaggedPtr)
#define SEMANTIC_BITSET_TYPE_LIST(V) \
V(Null, 1u << 1 | REPRESENTATION(kTaggedPtr)) \
V(Undefined, 1u << 2 | REPRESENTATION(kTaggedPtr)) \
V(Boolean, 1u << 3 | REPRESENTATION(kTaggedPtr)) \
V(UnsignedSmall, 1u << 4 | REPRESENTATION(kTagged | kUntaggedNumber)) \
V(OtherSignedSmall, 1u << 5 | REPRESENTATION(kTagged | kUntaggedNumber)) \
V(OtherUnsigned31, 1u << 6 | REPRESENTATION(kTagged | kUntaggedNumber)) \
V(OtherUnsigned32, 1u << 7 | REPRESENTATION(kTagged | kUntaggedNumber)) \
V(OtherSigned32, 1u << 8 | REPRESENTATION(kTagged | kUntaggedNumber)) \
V(MinusZero, 1u << 9 | REPRESENTATION(kTagged | kUntaggedNumber)) \
V(NaN, 1u << 10 | REPRESENTATION(kTagged | kUntaggedNumber)) \
V(OtherNumber, 1u << 11 | REPRESENTATION(kTagged | kUntaggedNumber)) \
V(Symbol, 1u << 12 | REPRESENTATION(kTaggedPtr)) \
V(InternalizedString, 1u << 13 | REPRESENTATION(kTaggedPtr)) \
V(OtherString, 1u << 14 | REPRESENTATION(kTaggedPtr)) \
V(Undetectable, 1u << 15 | REPRESENTATION(kTaggedPtr)) \
V(Array, 1u << 16 | REPRESENTATION(kTaggedPtr)) \
V(Buffer, 1u << 17 | REPRESENTATION(kTaggedPtr)) \
V(Function, 1u << 18 | REPRESENTATION(kTaggedPtr)) \
V(RegExp, 1u << 19 | REPRESENTATION(kTaggedPtr)) \
V(OtherObject, 1u << 20 | REPRESENTATION(kTaggedPtr)) \
V(Proxy, 1u << 21 | REPRESENTATION(kTaggedPtr)) \
V(Internal, 1u << 22 | REPRESENTATION(kTagged | kUntagged)) \
\
V(SignedSmall, kUnsignedSmall | kOtherSignedSmall) \
V(Signed32, kSignedSmall | kOtherUnsigned31 | kOtherSigned32) \
V(Unsigned32, kUnsignedSmall | kOtherUnsigned31 | kOtherUnsigned32) \
V(Integral32, kSigned32 | kUnsigned32) \
V(OrderedNumber, kIntegral32 | kMinusZero | kOtherNumber) \
V(Number, kOrderedNumber | kNaN) \
V(String, kInternalizedString | kOtherString) \
V(UniqueName, kSymbol | kInternalizedString) \
V(Name, kSymbol | kString) \
V(NumberOrString, kNumber | kString) \
V(Primitive, kNumber | kName | kBoolean | kNull | kUndefined) \
V(DetectableObject, kArray | kFunction | kRegExp | kOtherObject) \
V(DetectableReceiver, kDetectableObject | kProxy) \
V(Detectable, kDetectableReceiver | kNumber | kName) \
V(Object, kDetectableObject | kUndetectable) \
V(Receiver, kObject | kProxy) \
V(Unique, kBoolean | kUniqueName | kNull | kUndefined | \
kReceiver) \
V(NonNumber, kUnique | kString | kInternal) \
V(Any, 0xfffffffeu)
/*
* The following diagrams show how integers (in the mathematical sense) are
* divided among the different atomic numerical types.
*
* If SmiValuesAre31Bits():
*
* ON OS32 OSS US OU31 OU32 ON
* ______[_______[_______[_______[_______[_______[_______
* -2^31 -2^30 0 2^30 2^31 2^32
*
* Otherwise:
*
* ON OSS US OU32 ON
* ______[_______________[_______________[_______[_______
* -2^31 0 2^31 2^32
*
*
* E.g., OtherUnsigned32 (OU32) covers all integers from 2^31 to 2^32-1.
*
* NOTE: OtherSigned32 (OS32) and OU31 (OtherUnsigned31) are empty if Smis are
* 32-bit wide. They should thus never be used directly, only indirectly
* via e.g. Number.
*/
#define PROPER_BITSET_TYPE_LIST(V) \
REPRESENTATION_BITSET_TYPE_LIST(V) \
SEMANTIC_BITSET_TYPE_LIST(V)
#define BITSET_TYPE_LIST(V) \
MASK_BITSET_TYPE_LIST(V) \
PROPER_BITSET_TYPE_LIST(V)
// -----------------------------------------------------------------------------
// The abstract Type class, parameterized over the low-level representation.
// struct Config {
// typedef TypeImpl<Config> Type;
// typedef Base;
// typedef Struct;
// typedef Region;
// template<class> struct Handle { typedef type; } // No template typedefs...
// template<class T> static Handle<T>::type null_handle();
// template<class T> static Handle<T>::type handle(T* t); // !is_bitset(t)
// template<class T> static Handle<T>::type cast(Handle<Type>::type);
// static bool is_bitset(Type*);
// static bool is_class(Type*);
// static bool is_struct(Type*, int tag);
// static bitset as_bitset(Type*);
// static i::Handle<i::Map> as_class(Type*);
// static Handle<Struct>::type as_struct(Type*);
// static Type* from_bitset(bitset);
// static Handle<Type>::type from_bitset(bitset, Region*);
// static Handle<Type>::type from_class(i::Handle<Map>, Region*);
// static Handle<Type>::type from_struct(Handle<Struct>::type, int tag);
// static Handle<Struct>::type struct_create(int tag, int length, Region*);
// static void struct_shrink(Handle<Struct>::type, int length);
// static int struct_tag(Handle<Struct>::type);
// static int struct_length(Handle<Struct>::type);
// static Handle<Type>::type struct_get(Handle<Struct>::type, int);
// static void struct_set(Handle<Struct>::type, int, Handle<Type>::type);
// template<class V>
// static i::Handle<V> struct_get_value(Handle<Struct>::type, int);
// template<class V>
// static void struct_set_value(Handle<Struct>::type, int, i::Handle<V>);
// }
template<class Config>
class TypeImpl : public Config::Base {
public:
// Auxiliary types.
typedef uint32_t bitset; // Internal
class BitsetType; // Internal
class StructuralType; // Internal
class UnionType; // Internal
class ClassType;
class ConstantType;
class RangeType;
class ContextType;
class ArrayType;
class FunctionType;
typedef typename Config::template Handle<TypeImpl>::type TypeHandle;
typedef typename Config::template Handle<ClassType>::type ClassHandle;
typedef typename Config::template Handle<ConstantType>::type ConstantHandle;
typedef typename Config::template Handle<RangeType>::type RangeHandle;
typedef typename Config::template Handle<ContextType>::type ContextHandle;
typedef typename Config::template Handle<ArrayType>::type ArrayHandle;
typedef typename Config::template Handle<FunctionType>::type FunctionHandle;
typedef typename Config::template Handle<UnionType>::type UnionHandle;
typedef typename Config::Region Region;
// Constructors.
#define DEFINE_TYPE_CONSTRUCTOR(type, value) \
static TypeImpl* type() { \
return BitsetType::New(BitsetType::k##type); \
} \
static TypeHandle type(Region* region) { \
return BitsetType::New(BitsetType::k##type, region); \
}
PROPER_BITSET_TYPE_LIST(DEFINE_TYPE_CONSTRUCTOR)
#undef DEFINE_TYPE_CONSTRUCTOR
static TypeHandle Class(i::Handle<i::Map> map, Region* region) {
return ClassType::New(map, region);
}
static TypeHandle Constant(i::Handle<i::Object> value, Region* region) {
return ConstantType::New(value, region);
}
static TypeHandle Range(
i::Handle<i::Object> min, i::Handle<i::Object> max, Region* region) {
return RangeType::New(min, max, region);
}
static TypeHandle Context(TypeHandle outer, Region* region) {
return ContextType::New(outer, region);
}
static TypeHandle Array(TypeHandle element, Region* region) {
return ArrayType::New(element, region);
}
static FunctionHandle Function(
TypeHandle result, TypeHandle receiver, int arity, Region* region) {
return FunctionType::New(result, receiver, arity, region);
}
static TypeHandle Function(TypeHandle result, Region* region) {
return Function(result, Any(region), 0, region);
}
static TypeHandle Function(
TypeHandle result, TypeHandle param0, Region* region) {
FunctionHandle function = Function(result, Any(region), 1, region);
function->InitParameter(0, param0);
return function;
}
static TypeHandle Function(
TypeHandle result, TypeHandle param0, TypeHandle param1, Region* region) {
FunctionHandle function = Function(result, Any(region), 2, region);
function->InitParameter(0, param0);
function->InitParameter(1, param1);
return function;
}
static TypeHandle Function(
TypeHandle result, TypeHandle param0, TypeHandle param1,
TypeHandle param2, Region* region) {
FunctionHandle function = Function(result, Any(region), 3, region);
function->InitParameter(0, param0);
function->InitParameter(1, param1);
function->InitParameter(2, param2);
return function;
}
static TypeHandle Union(TypeHandle type1, TypeHandle type2, Region* reg);
static TypeHandle Intersect(TypeHandle type1, TypeHandle type2, Region* reg);
static TypeImpl* Union(TypeImpl* type1, TypeImpl* type2) {
return BitsetType::New(type1->AsBitset() | type2->AsBitset());
}
static TypeImpl* Intersect(TypeImpl* type1, TypeImpl* type2) {
return BitsetType::New(type1->AsBitset() & type2->AsBitset());
}
static TypeHandle Of(double value, Region* region) {
return Config::from_bitset(BitsetType::Lub(value), region);
}
static TypeHandle Of(i::Object* value, Region* region) {
return Config::from_bitset(BitsetType::Lub(value), region);
}
static TypeHandle Of(i::Handle<i::Object> value, Region* region) {
return Of(*value, region);
}
// Predicates.
bool IsInhabited() { return BitsetType::IsInhabited(this->BitsetLub()); }
bool Is(TypeImpl* that) { return this == that || this->SlowIs(that); }
template<class TypeHandle>
bool Is(TypeHandle that) { return this->Is(*that); }
bool Maybe(TypeImpl* that);
template<class TypeHandle>
bool Maybe(TypeHandle that) { return this->Maybe(*that); }
bool Equals(TypeImpl* that) { return this->Is(that) && that->Is(this); }
template<class TypeHandle>
bool Equals(TypeHandle that) { return this->Equals(*that); }
// Equivalent to Constant(val)->Is(this), but avoiding allocation.
bool Contains(i::Object* val);
bool Contains(i::Handle<i::Object> val) { return this->Contains(*val); }
// State-dependent versions of the above that consider subtyping between
// a constant and its map class.
inline static TypeHandle NowOf(i::Object* value, Region* region);
static TypeHandle NowOf(i::Handle<i::Object> value, Region* region) {
return NowOf(*value, region);
}
bool NowIs(TypeImpl* that);
template<class TypeHandle>
bool NowIs(TypeHandle that) { return this->NowIs(*that); }
inline bool NowContains(i::Object* val);
bool NowContains(i::Handle<i::Object> val) { return this->NowContains(*val); }
bool NowStable();
// Inspection.
bool IsClass() {
return Config::is_class(this)
|| Config::is_struct(this, StructuralType::kClassTag);
}
bool IsConstant() {
return Config::is_struct(this, StructuralType::kConstantTag);
}
bool IsRange() {
return Config::is_struct(this, StructuralType::kRangeTag);
}
bool IsContext() {
return Config::is_struct(this, StructuralType::kContextTag);
}
bool IsArray() {
return Config::is_struct(this, StructuralType::kArrayTag);
}
bool IsFunction() {
return Config::is_struct(this, StructuralType::kFunctionTag);
}
ClassType* AsClass() { return ClassType::cast(this); }
ConstantType* AsConstant() { return ConstantType::cast(this); }
RangeType* AsRange() { return RangeType::cast(this); }
ContextType* AsContext() { return ContextType::cast(this); }
ArrayType* AsArray() { return ArrayType::cast(this); }
FunctionType* AsFunction() { return FunctionType::cast(this); }
// Minimum and maximum of a numeric type.
// These functions do not distinguish between -0 and +0. If the type equals
// kNaN, they return NaN; otherwise kNaN is ignored. Only call these
// functions on subtypes of Number.
double Min();
double Max();
int NumClasses();
int NumConstants();
template<class T> class Iterator;
Iterator<i::Map> Classes() {
if (this->IsBitset()) return Iterator<i::Map>();
return Iterator<i::Map>(Config::handle(this));
}
Iterator<i::Object> Constants() {
if (this->IsBitset()) return Iterator<i::Object>();
return Iterator<i::Object>(Config::handle(this));
}
// Casting and conversion.
static inline TypeImpl* cast(typename Config::Base* object);
template<class OtherTypeImpl>
static TypeHandle Convert(
typename OtherTypeImpl::TypeHandle type, Region* region);
// Printing.
enum PrintDimension { BOTH_DIMS, SEMANTIC_DIM, REPRESENTATION_DIM };
void PrintTo(std::ostream& os, PrintDimension dim = BOTH_DIMS); // NOLINT
#ifdef DEBUG
void Print();
#endif
protected:
// Friends.
template<class> friend class Iterator;
template<class> friend class TypeImpl;
// Handle conversion.
template<class T>
static typename Config::template Handle<T>::type handle(T* type) {
return Config::handle(type);
}
TypeImpl* unhandle() { return this; }
// Internal inspection.
bool IsNone() { return this == None(); }
bool IsAny() { return this == Any(); }
bool IsBitset() { return Config::is_bitset(this); }
bool IsUnion() { return Config::is_struct(this, StructuralType::kUnionTag); }
bitset AsBitset() {
DCHECK(this->IsBitset());
return static_cast<BitsetType*>(this)->Bitset();
}
UnionType* AsUnion() { return UnionType::cast(this); }
// Auxiliary functions.
bitset BitsetGlb() { return BitsetType::Glb(this); }
bitset BitsetLub() { return BitsetType::Lub(this); }
bool SlowIs(TypeImpl* that);
static bool IsInteger(double x) {
return nearbyint(x) == x && !i::IsMinusZero(x); // Allows for infinities.
}
static bool IsInteger(i::Object* x) {
return x->IsNumber() && IsInteger(x->Number());
}
struct Limits {
i::Handle<i::Object> min;
i::Handle<i::Object> max;
Limits(i::Handle<i::Object> min, i::Handle<i::Object> max) :
min(min), max(max) {}
explicit Limits(RangeType* range) :
min(range->Min()), max(range->Max()) {}
};
static Limits Intersect(Limits lhs, Limits rhs);
static Limits Union(Limits lhs, Limits rhs);
static bool Overlap(RangeType* lhs, RangeType* rhs);
static bool Contains(RangeType* lhs, RangeType* rhs);
static bool Contains(RangeType* range, i::Object* val);
RangeType* GetRange();
static int UpdateRange(
RangeHandle type, UnionHandle result, int size, Region* region);
bool SimplyEquals(TypeImpl* that);
template<class TypeHandle>
bool SimplyEquals(TypeHandle that) { return this->SimplyEquals(*that); }
static int AddToUnion(
TypeHandle type, UnionHandle result, int size, Region* region);
static int IntersectAux(
TypeHandle type, TypeHandle other,
UnionHandle result, int size, Region* region);
static TypeHandle NormalizeUnion(UnionHandle unioned, int size);
};
// -----------------------------------------------------------------------------
// Bitset types (internal).
template<class Config>
class TypeImpl<Config>::BitsetType : public TypeImpl<Config> {
protected:
friend class TypeImpl<Config>;
enum {
#define DECLARE_TYPE(type, value) k##type = (value),
BITSET_TYPE_LIST(DECLARE_TYPE)
#undef DECLARE_TYPE
kUnusedEOL = 0
};
bitset Bitset() { return Config::as_bitset(this); }
static TypeImpl* New(bitset bits) {
DCHECK(bits == kNone || IsInhabited(bits));
return Config::from_bitset(bits);
}
static TypeHandle New(bitset bits, Region* region) {
DCHECK(bits == kNone || IsInhabited(bits));
return Config::from_bitset(bits, region);
}
// TODO(neis): Eventually allow again for types with empty semantics
// part and modify intersection and possibly subtyping accordingly.
static bool IsInhabited(bitset bits) {
return bits & kSemantic;
}
static bool Is(bitset bits1, bitset bits2) {
return (bits1 | bits2) == bits2;
}
static double Min(bitset);
static double Max(bitset);
static bitset Glb(TypeImpl* type); // greatest lower bound that's a bitset
static bitset Lub(TypeImpl* type); // least upper bound that's a bitset
static bitset Lub(i::Map* map);
static bitset Lub(i::Object* value);
static bitset Lub(double value);
static bitset Lub(double min, double max);
static const char* Name(bitset);
static void Print(std::ostream& os, bitset); // NOLINT
#ifdef DEBUG
static void Print(bitset);
#endif
private:
struct BitsetMin{
bitset bits;
double min;
};
static const BitsetMin BitsetMins31[];
static const BitsetMin BitsetMins32[];
static const BitsetMin* BitsetMins() {
return i::SmiValuesAre31Bits() ? BitsetMins31 : BitsetMins32;
}
static size_t BitsetMinsSize() {
return i::SmiValuesAre31Bits() ? 7 : 5;
/* arraysize(BitsetMins31) : arraysize(BitsetMins32); */
// Using arraysize here doesn't compile on Windows.
}
};
// -----------------------------------------------------------------------------
// Superclass for non-bitset types (internal).
// Contains a tag and a variable number of type or value fields.
template<class Config>
class TypeImpl<Config>::StructuralType : public TypeImpl<Config> {
protected:
template<class> friend class TypeImpl;
friend struct ZoneTypeConfig; // For tags.
friend struct HeapTypeConfig;
enum Tag {
kClassTag,
kConstantTag,
kRangeTag,
kContextTag,
kArrayTag,
kFunctionTag,
kUnionTag
};
int Length() {
return Config::struct_length(Config::as_struct(this));
}
TypeHandle Get(int i) {
DCHECK(0 <= i && i < this->Length());
return Config::struct_get(Config::as_struct(this), i);
}
void Set(int i, TypeHandle type) {
DCHECK(0 <= i && i < this->Length());
Config::struct_set(Config::as_struct(this), i, type);
}
void Shrink(int length) {
DCHECK(2 <= length && length <= this->Length());
Config::struct_shrink(Config::as_struct(this), length);
}
template<class V> i::Handle<V> GetValue(int i) {
DCHECK(0 <= i && i < this->Length());
return Config::template struct_get_value<V>(Config::as_struct(this), i);
}
template<class V> void SetValue(int i, i::Handle<V> x) {
DCHECK(0 <= i && i < this->Length());
Config::struct_set_value(Config::as_struct(this), i, x);
}
static TypeHandle New(Tag tag, int length, Region* region) {
DCHECK(1 <= length);
return Config::from_struct(Config::struct_create(tag, length, region));
}
};
// -----------------------------------------------------------------------------
// Union types (internal).
// A union is a structured type with the following invariants:
// - its length is at least 2
// - at most one field is a bitset, and it must go into index 0
// - no field is a union
// - no field is a subtype of any other field
template<class Config>
class TypeImpl<Config>::UnionType : public StructuralType {
public:
static UnionHandle New(int length, Region* region) {
return Config::template cast<UnionType>(
StructuralType::New(StructuralType::kUnionTag, length, region));
}
static UnionType* cast(TypeImpl* type) {
DCHECK(type->IsUnion());
return static_cast<UnionType*>(type);
}
bool Wellformed();
};
// -----------------------------------------------------------------------------
// Class types.
template<class Config>
class TypeImpl<Config>::ClassType : public StructuralType {
public:
TypeHandle Bound(Region* region) {
return Config::is_class(this) ?
BitsetType::New(BitsetType::Lub(*Config::as_class(this)), region) :
this->Get(0);
}
i::Handle<i::Map> Map() {
return Config::is_class(this) ? Config::as_class(this) :
this->template GetValue<i::Map>(1);
}
static ClassHandle New(i::Handle<i::Map> map, Region* region) {
ClassHandle type =
Config::template cast<ClassType>(Config::from_class(map, region));
if (!type->IsClass()) {
type = Config::template cast<ClassType>(
StructuralType::New(StructuralType::kClassTag, 2, region));
type->Set(0, BitsetType::New(BitsetType::Lub(*map), region));
type->SetValue(1, map);
}
return type;
}
static ClassType* cast(TypeImpl* type) {
DCHECK(type->IsClass());
return static_cast<ClassType*>(type);
}
};
// -----------------------------------------------------------------------------
// Constant types.
template<class Config>
class TypeImpl<Config>::ConstantType : public StructuralType {
public:
TypeHandle Bound() { return this->Get(0); }
i::Handle<i::Object> Value() { return this->template GetValue<i::Object>(1); }
static ConstantHandle New(i::Handle<i::Object> value, Region* region) {
ConstantHandle type = Config::template cast<ConstantType>(
StructuralType::New(StructuralType::kConstantTag, 2, region));
type->Set(0, BitsetType::New(BitsetType::Lub(*value), region));
type->SetValue(1, value);
return type;
}
static ConstantType* cast(TypeImpl* type) {
DCHECK(type->IsConstant());
return static_cast<ConstantType*>(type);
}
};
// TODO(neis): Also cache value if numerical.
// TODO(neis): Allow restricting the representation.
// -----------------------------------------------------------------------------
// Range types.
template<class Config>
class TypeImpl<Config>::RangeType : public StructuralType {
public:
int BitsetLub() { return this->Get(0)->AsBitset(); }
i::Handle<i::Object> Min() { return this->template GetValue<i::Object>(1); }
i::Handle<i::Object> Max() { return this->template GetValue<i::Object>(2); }
static RangeHandle New(
i::Handle<i::Object> min, i::Handle<i::Object> max, Region* region) {
DCHECK(IsInteger(min->Number()) && IsInteger(max->Number()));
DCHECK(min->Number() <= max->Number());
RangeHandle type = Config::template cast<RangeType>(
StructuralType::New(StructuralType::kRangeTag, 3, region));
type->Set(0, BitsetType::New(
BitsetType::Lub(min->Number(), max->Number()), region));
type->SetValue(1, min);
type->SetValue(2, max);
return type;
}
static RangeHandle New(Limits lim, Region* region) {
return New(lim.min, lim.max, region);
}
static RangeType* cast(TypeImpl* type) {
DCHECK(type->IsRange());
return static_cast<RangeType*>(type);
}
};
// TODO(neis): Also cache min and max values.
// TODO(neis): Allow restricting the representation.
// -----------------------------------------------------------------------------
// Context types.
template<class Config>
class TypeImpl<Config>::ContextType : public StructuralType {
public:
TypeHandle Outer() { return this->Get(0); }
static ContextHandle New(TypeHandle outer, Region* region) {
ContextHandle type = Config::template cast<ContextType>(
StructuralType::New(StructuralType::kContextTag, 1, region));
type->Set(0, outer);
return type;
}
static ContextType* cast(TypeImpl* type) {
DCHECK(type->IsContext());
return static_cast<ContextType*>(type);
}
};
// -----------------------------------------------------------------------------
// Array types.
template<class Config>
class TypeImpl<Config>::ArrayType : public StructuralType {
public:
TypeHandle Element() { return this->Get(0); }
static ArrayHandle New(TypeHandle element, Region* region) {
ArrayHandle type = Config::template cast<ArrayType>(
StructuralType::New(StructuralType::kArrayTag, 1, region));
type->Set(0, element);
return type;
}
static ArrayType* cast(TypeImpl* type) {
DCHECK(type->IsArray());
return static_cast<ArrayType*>(type);
}
};
// -----------------------------------------------------------------------------
// Function types.
template<class Config>
class TypeImpl<Config>::FunctionType : public StructuralType {
public:
int Arity() { return this->Length() - 2; }
TypeHandle Result() { return this->Get(0); }
TypeHandle Receiver() { return this->Get(1); }
TypeHandle Parameter(int i) { return this->Get(2 + i); }
void InitParameter(int i, TypeHandle type) { this->Set(2 + i, type); }
static FunctionHandle New(
TypeHandle result, TypeHandle receiver, int arity, Region* region) {
FunctionHandle type = Config::template cast<FunctionType>(
StructuralType::New(StructuralType::kFunctionTag, 2 + arity, region));
type->Set(0, result);
type->Set(1, receiver);
return type;
}
static FunctionType* cast(TypeImpl* type) {
DCHECK(type->IsFunction());
return static_cast<FunctionType*>(type);
}
};
// -----------------------------------------------------------------------------
// Type iterators.
template<class Config> template<class T>
class TypeImpl<Config>::Iterator {
public:
bool Done() const { return index_ < 0; }
i::Handle<T> Current();
void Advance();
private:
template<class> friend class TypeImpl;
Iterator() : index_(-1) {}
explicit Iterator(TypeHandle type) : type_(type), index_(-1) {
Advance();
}
inline bool matches(TypeHandle type);
inline TypeHandle get_type();
TypeHandle type_;
int index_;
};
// -----------------------------------------------------------------------------
// Zone-allocated types; they are either (odd) integers to represent bitsets, or
// (even) pointers to structures for everything else.
struct ZoneTypeConfig {
typedef TypeImpl<ZoneTypeConfig> Type;
class Base {};
typedef void* Struct;
typedef i::Zone Region;
template<class T> struct Handle { typedef T* type; };
template<class T> static inline T* null_handle();
template<class T> static inline T* handle(T* type);
template<class T> static inline T* cast(Type* type);
static inline bool is_bitset(Type* type);
static inline bool is_class(Type* type);
static inline bool is_struct(Type* type, int tag);
static inline Type::bitset as_bitset(Type* type);
static inline i::Handle<i::Map> as_class(Type* type);
static inline Struct* as_struct(Type* type);
static inline Type* from_bitset(Type::bitset);
static inline Type* from_bitset(Type::bitset, Zone* zone);
static inline Type* from_class(i::Handle<i::Map> map, Zone* zone);
static inline Type* from_struct(Struct* structured);
static inline Struct* struct_create(int tag, int length, Zone* zone);
static inline void struct_shrink(Struct* structure, int length);
static inline int struct_tag(Struct* structure);
static inline int struct_length(Struct* structure);
static inline Type* struct_get(Struct* structure, int i);
static inline void struct_set(Struct* structure, int i, Type* type);
template<class V>
static inline i::Handle<V> struct_get_value(Struct* structure, int i);
template<class V> static inline void struct_set_value(
Struct* structure, int i, i::Handle<V> x);
};
typedef TypeImpl<ZoneTypeConfig> Type;
// -----------------------------------------------------------------------------
// Heap-allocated types; either smis for bitsets, maps for classes, boxes for
// constants, or fixed arrays for unions.
struct HeapTypeConfig {
typedef TypeImpl<HeapTypeConfig> Type;
typedef i::Object Base;
typedef i::FixedArray Struct;
typedef i::Isolate Region;
template<class T> struct Handle { typedef i::Handle<T> type; };
template<class T> static inline i::Handle<T> null_handle();
template<class T> static inline i::Handle<T> handle(T* type);
template<class T> static inline i::Handle<T> cast(i::Handle<Type> type);
static inline bool is_bitset(Type* type);
static inline bool is_class(Type* type);
static inline bool is_struct(Type* type, int tag);
static inline Type::bitset as_bitset(Type* type);
static inline i::Handle<i::Map> as_class(Type* type);
static inline i::Handle<Struct> as_struct(Type* type);
static inline Type* from_bitset(Type::bitset);
static inline i::Handle<Type> from_bitset(Type::bitset, Isolate* isolate);
static inline i::Handle<Type> from_class(
i::Handle<i::Map> map, Isolate* isolate);
static inline i::Handle<Type> from_struct(i::Handle<Struct> structure);
static inline i::Handle<Struct> struct_create(
int tag, int length, Isolate* isolate);
static inline void struct_shrink(i::Handle<Struct> structure, int length);
static inline int struct_tag(i::Handle<Struct> structure);
static inline int struct_length(i::Handle<Struct> structure);
static inline i::Handle<Type> struct_get(i::Handle<Struct> structure, int i);
static inline void struct_set(
i::Handle<Struct> structure, int i, i::Handle<Type> type);
template<class V>
static inline i::Handle<V> struct_get_value(
i::Handle<Struct> structure, int i);
template<class V>
static inline void struct_set_value(
i::Handle<Struct> structure, int i, i::Handle<V> x);
};
typedef TypeImpl<HeapTypeConfig> HeapType;
// -----------------------------------------------------------------------------
// Type bounds. A simple struct to represent a pair of lower/upper types.
template<class Config>
struct BoundsImpl {
typedef TypeImpl<Config> Type;
typedef typename Type::TypeHandle TypeHandle;
typedef typename Type::Region Region;
TypeHandle lower;
TypeHandle upper;
BoundsImpl() : // Make sure accessing uninitialized bounds crashes big-time.
lower(Config::template null_handle<Type>()),
upper(Config::template null_handle<Type>()) {}
explicit BoundsImpl(TypeHandle t) : lower(t), upper(t) {}
BoundsImpl(TypeHandle l, TypeHandle u) : lower(l), upper(u) {
DCHECK(lower->Is(upper));
}
// Unrestricted bounds.
static BoundsImpl Unbounded(Region* region) {
return BoundsImpl(Type::None(region), Type::Any(region));
}
// Meet: both b1 and b2 are known to hold.
static BoundsImpl Both(BoundsImpl b1, BoundsImpl b2, Region* region) {
TypeHandle lower = Type::Union(b1.lower, b2.lower, region);
TypeHandle upper = Type::Intersect(b1.upper, b2.upper, region);
// Lower bounds are considered approximate, correct as necessary.
lower = Type::Intersect(lower, upper, region);
return BoundsImpl(lower, upper);
}
// Join: either b1 or b2 is known to hold.
static BoundsImpl Either(BoundsImpl b1, BoundsImpl b2, Region* region) {
TypeHandle lower = Type::Intersect(b1.lower, b2.lower, region);
TypeHandle upper = Type::Union(b1.upper, b2.upper, region);
return BoundsImpl(lower, upper);
}
static BoundsImpl NarrowLower(BoundsImpl b, TypeHandle t, Region* region) {
// Lower bounds are considered approximate, correct as necessary.
t = Type::Intersect(t, b.upper, region);
TypeHandle lower = Type::Union(b.lower, t, region);
return BoundsImpl(lower, b.upper);
}
static BoundsImpl NarrowUpper(BoundsImpl b, TypeHandle t, Region* region) {
TypeHandle lower = Type::Intersect(b.lower, t, region);
TypeHandle upper = Type::Intersect(b.upper, t, region);
return BoundsImpl(lower, upper);
}
bool Narrows(BoundsImpl that) {
return that.lower->Is(this->lower) && this->upper->Is(that.upper);
}
};
typedef BoundsImpl<ZoneTypeConfig> Bounds;
} } // namespace v8::internal
#endif // V8_TYPES_H_
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