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# What's changed? - Record the location of properties for table types (closes #802) - Implement stricter UTF-8 validations as per the RFC (https://github.com/luau-lang/rfcs/pull/1) - Implement `buffer` as a new type in both the old and new solvers. - Changed errors produced by some `buffer` builtins to be a bit more generic to avoid platform-dependent error messages. - Fixed a bug where `Unifier` would copy some persistent types, tripping some internal assertions. - Type checking rules on relational operators is now a little bit more lax. - Improve dead code elimination for some `if` statements with complex always-false conditions ## New type solver - Dataflow analysis now generates phi nodes on exit of branches. - Dataflow analysis avoids producing a new definition for locals or properties that are not owned by that loop. - If a function parameter has been constrained to `never`, report errors at all uses of that parameter within that function. - Switch to using the new `Luau::Set` to replace `std::unordered_set` to alleviate some poor allocation characteristics which was negatively affecting overall performance. - Subtyping can now report many failing reasons instead of just the first one that we happened to find during the test. - Subtyping now also report reasons for type pack mismatches. - When visiting `if` statements or expressions, the resulting context are the common terms in both branches. ## Native codegen - Implement support for `buffer` builtins to its IR for x64 and A64. - Optimized `table.insert` by not inserting a table barrier if it is fastcalled with a constant. ## Internal Contributors Co-authored-by: Aaron Weiss <aaronweiss@roblox.com> Co-authored-by: Alexander McCord <amccord@roblox.com> Co-authored-by: Andy Friesen <afriesen@roblox.com> Co-authored-by: Arseny Kapoulkine <arseny@roblox.com> Co-authored-by: Aviral Goel <agoel@roblox.com> Co-authored-by: Lily Brown <lbrown@roblox.com> Co-authored-by: Vyacheslav Egorov <vegorov@roblox.com>
85 lines
2.3 KiB
C++
85 lines
2.3 KiB
C++
// This file is part of the Luau programming language and is licensed under MIT License; see LICENSE.txt for details
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#pragma once
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#include "Luau/NotNull.h"
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#include "Luau/TypedAllocator.h"
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#include "Luau/Variant.h"
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#include <string>
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#include <optional>
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namespace Luau
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{
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struct Def;
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using DefId = NotNull<const Def>;
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/**
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* A cell is a "single-object" value.
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*
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* Leaky implementation note: sometimes "multiple-object" values, but none of which were interesting enough to warrant creating a phi node instead.
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* That can happen because there's no point in creating a phi node that points to either resultant in `if math.random() > 0.5 then 5 else "hello"`.
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* This might become of utmost importance if we wanted to do some backward reasoning, e.g. if `5` is taken, then `cond` must be `truthy`.
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*/
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struct Cell
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{
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bool subscripted = false;
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};
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/**
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* A phi node is a union of cells.
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*
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* We need this because we're statically evaluating a program, and sometimes a place may be assigned with
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* different cells, and when that happens, we need a special data type that merges in all the cells
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* that will flow into that specific place. For example, consider this simple program:
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*
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* ```
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* x-1
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* if cond() then
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* x-2 = 5
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* else
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* x-3 = "hello"
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* end
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* x-4 : {x-2, x-3}
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* ```
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*
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* At x-4, we know for a fact statically that either `5` or `"hello"` can flow into the variable `x` after the branch, but
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* we cannot make any definitive decisions about which one, so we just take in both.
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*/
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struct Phi
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{
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std::vector<DefId> operands;
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};
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/**
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* We statically approximate a value at runtime using a symbolic value, which we call a Def.
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*
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* DataFlowGraphBuilder will allocate these defs as a stand-in for some Luau values, and bind them to places that
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* can hold a Luau value, and then observes how those defs will commute as it statically evaluate the program.
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*
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* It must also be noted that defs are a cyclic graph, so it is not safe to recursively traverse into it expecting it to terminate.
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*/
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struct Def
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{
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using V = Variant<struct Cell, struct Phi>;
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V v;
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};
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template<typename T>
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const T* get(DefId def)
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{
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return get_if<T>(&def->v);
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}
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bool containsSubscriptedDefinition(DefId def);
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struct DefArena
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{
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TypedAllocator<Def> allocator;
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DefId freshCell(bool subscripted = false);
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DefId phi(DefId a, DefId b);
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};
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} // namespace Luau
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