luau/Analysis/include/Luau/Unifier2.h
Andy Friesen 0b2755f964
Sync to upstream/release/589 (#1000)
* Progress toward a diffing algorithm for types. We hope that this will
be useful for writing clearer error messages.
* Add a missing recursion limiter in `Unifier::tryUnifyTables`. This was
causing a crash in certain situations.
* Luau heap graph enumeration improvements:
    * Weak references are not reported
    * Added tag as a fallback name of non-string table links
* Included top Luau function information in thread name to understand
where thread might be suspended
* Constant folding for `math.pi` and `math.huge` at -O2
* Optimize `string.format` and `%*`
* This change makes string interpolation 1.5x-2x faster depending on the
number and type of formatted components, assuming a few are using
primitive types, and reduces associated GC pressure.

New type checker:

* Initial work toward tracking the upper and lower bounds of types
accurately.

Native code generation (JIT):

* Add IrCmd::CHECK_TRUTHY for improved assert fast-calls
* Do not compute type map for modules without types
* Capture metatable+readonly state for NEW_TABLE IR instructions
* Replace JUMP_CMP_ANY with CMP_ANY and existing JUMP_EQ_INT
* Add support for exits to VM with reentry lock in VmExit

---------

Co-authored-by: Arseny Kapoulkine <arseny.kapoulkine@gmail.com>
Co-authored-by: Vyacheslav Egorov <vegorov@roblox.com>
2023-08-04 12:18:54 -07:00

75 lines
2 KiB
C++

// This file is part of the Luau programming language and is licensed under MIT License; see LICENSE.txt for details
#pragma once
#include "Luau/DenseHash.h"
#include "Luau/NotNull.h"
#include <optional>
#include <vector>
#include <utility>
namespace Luau
{
using TypeId = const struct Type*;
using TypePackId = const struct TypePackVar*;
struct BuiltinTypes;
struct InternalErrorReporter;
struct Scope;
struct TypeArena;
enum class OccursCheckResult
{
Pass,
Fail
};
struct Unifier2
{
NotNull<TypeArena> arena;
NotNull<BuiltinTypes> builtinTypes;
NotNull<InternalErrorReporter> ice;
int recursionCount = 0;
int recursionLimit = 0;
Unifier2(NotNull<TypeArena> arena, NotNull<BuiltinTypes> builtinTypes, NotNull<InternalErrorReporter> ice);
/** Attempt to commit the subtype relation subTy <: superTy to the type
* graph.
*
* @returns true if successful.
*
* Note that incoherent types can and will successfully be unified. We stop
* when we *cannot know* how to relate the provided types, not when doing so
* would narrow something down to never or broaden it to unknown.
*
* Presently, the only way unification can fail is if we attempt to bind one
* free TypePack to another and encounter an occurs check violation.
*/
bool unify(TypeId subTy, TypeId superTy);
// TODO think about this one carefully. We don't do unions or intersections of type packs
bool unify(TypePackId subTp, TypePackId superTp);
std::optional<TypeId> generalize(NotNull<Scope> scope, TypeId ty);
private:
/**
* @returns simplify(left | right)
*/
TypeId mkUnion(TypeId left, TypeId right);
/**
* @returns simplify(left & right)
*/
TypeId mkIntersection(TypeId left, TypeId right);
// Returns true if needle occurs within haystack already. ie if we bound
// needle to haystack, would a cyclic TypePack result?
OccursCheckResult occursCheck(DenseHashSet<TypePackId>& seen, TypePackId needle, TypePackId haystack);
};
}