luau/Analysis/include/Luau/Def.h
Andy Friesen 74c532053f
Sync to upstream/release/604 (#1106)
New Solver

* New algorithm for inferring the types of locals that have no
annotations. This
algorithm is very conservative by default, but is augmented with some
control
  flow awareness to handle most common scenarios.
* Fix bugs in type inference of tables
* Improve performance of by switching out standard C++ containers for
`DenseHashMap`
* Infrastructure to support clearer error messages in strict mode

Native Code Generation

* Fix a lowering issue with buffer.writeu8 and 0x80-0xff values: A
constant
  argument wasn't truncated to the target type range and that causes an
  assertion failure in `build.mov`.
* Store full lightuserdata value in loop iteration protocol lowering
* Add analysis to compute function bytecode distribution
* This includes a class to analyze the bytecode operator distribution
per
function and a CLI tool that produces a JSON report. See the new cmake
      target `Luau.Bytecode.CLI`

---------

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: Aviral Goel <agoel@roblox.com>
Co-authored-by: Lily Brown <lbrown@roblox.com>
Co-authored-by: Vyacheslav Egorov <vegorov@roblox.com>
2023-11-17 10:46:18 -08:00

87 lines
2.4 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/NotNull.h"
#include "Luau/TypedAllocator.h"
#include "Luau/Variant.h"
#include <string>
#include <optional>
namespace Luau
{
struct Def;
using DefId = NotNull<const Def>;
/**
* A cell is a "single-object" value.
*
* Leaky implementation note: sometimes "multiple-object" values, but none of which were interesting enough to warrant creating a phi node instead.
* 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"`.
* 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`.
*/
struct Cell
{
bool subscripted = false;
};
/**
* A phi node is a union of cells.
*
* We need this because we're statically evaluating a program, and sometimes a place may be assigned with
* different cells, and when that happens, we need a special data type that merges in all the cells
* that will flow into that specific place. For example, consider this simple program:
*
* ```
* x-1
* if cond() then
* x-2 = 5
* else
* x-3 = "hello"
* end
* x-4 : {x-2, x-3}
* ```
*
* At x-4, we know for a fact statically that either `5` or `"hello"` can flow into the variable `x` after the branch, but
* we cannot make any definitive decisions about which one, so we just take in both.
*/
struct Phi
{
std::vector<DefId> operands;
};
/**
* We statically approximate a value at runtime using a symbolic value, which we call a Def.
*
* DataFlowGraphBuilder will allocate these defs as a stand-in for some Luau values, and bind them to places that
* can hold a Luau value, and then observes how those defs will commute as it statically evaluate the program.
*
* 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.
*/
struct Def
{
using V = Variant<struct Cell, struct Phi>;
V v;
};
template<typename T>
const T* get(DefId def)
{
return get_if<T>(&def->v);
}
bool containsSubscriptedDefinition(DefId def);
struct DefArena
{
TypedAllocator<Def> allocator;
DefId freshCell(bool subscripted = false);
DefId phi(DefId a, DefId b);
DefId phi(const std::vector<DefId>& defs);
};
} // namespace Luau