* Fixed rare use-after-free in analysis during table unification
A lot of work these past months went into two new Luau components:
* A near full rewrite of the typechecker using a new deferred constraint
resolution system
* Native code generation for AoT/JiT compilation of VM bytecode into x64
(avx)/arm64 instructions
Both of these components are far from finished and we don't provide
documentation on building and using them at this point.
However, curious community members expressed interest in learning about
changes that go into these components each week, so we are now listing
them here in the 'sync' pull request descriptions.
---
New typechecker can be enabled by setting
DebugLuauDeferredConstraintResolution flag to 'true'.
It is considered unstable right now, so try it at your own risk.
Even though it already provides better type inference than the current
one in some cases, our main goal right now is to reach feature parity
with current typechecker.
Features which improve over the capabilities of the current typechecker
are marked as '(NEW)'.
Changes to new typechecker:
* Regular for loop index and parameters are now typechecked
* Invalid type annotations on local variables are ignored to improve
autocomplete
* Fixed missing autocomplete type suggestions for function arguments
* Type reduction is now performed to produce simpler types to be
presented to the user (error messages, custom LSPs)
* Internally, complex types like '((number | string) & ~(false?)) |
string' can be produced, which is just 'string | number' when simplified
* Fixed spots where support for unknown and never types was missing
* (NEW) Length operator '#' is now valid to use on top table type, this
type comes up when doing typeof(x) == "table" guards and isn't available
in current typechecker
---
Changes to native code generation:
* Additional math library fast calls are now lowered to x64: math.ldexp,
math.round, math.frexp, math.modf, math.sign and math.clamp
`lua_getupvalue()` and `lua_setupvalue()` don't behave as expected when
working with Lua closure whose `Proto` has no debug info. The code
currently uses `sizeupvalues` to do bounds checking of upvalue indices,
but that's the size of the upvalue _names_ array. It will always be `0`
if the `Proto` doesn't have debug info.
This uses `nups` instead, and just returns `""` as the upvalue name if
we don't have one, same as for C closures.
Co-authored-by: Harold Cindy <HaroldCindy@users.noreply.github.com>
* Fix autocompletion of if-then-else expressions
* Fix a potential crash surrounding improper use of `%*` in a string
format specifier
* All Python scripts now invoke Python via `python3` rather than
`python`.
* Improved error handling for string interpolation with too many
arguments.
Co-authored-by: Arseny Kapoulkine <arseny.kapoulkine@gmail.com>
Co-authored-by: Vyacheslav Egorov <vegorov@roblox.com>
This is useful in particular if redefine `LUAI_MAXCSTACK` to a higher
value than the current one (8000).
Ie. passing `-D LUAI_MAXCSTACK=1000000` would not work as overlaps with
`LUA_REGISTRYINDEX` and below.
* Type mismatch errors now mention if unification failed in covariant or
invariant context, to explain why sometimes derived class can't be
converted to base class or why `T` can't be converted into `T?` and so
on
* Class type indexing is no longer an error in non-strict mode (still an
error in strict mode)
* Fixed cyclic type packs not being displayed in the type
* Added an error when unrelated types are compared with `==`/`~=`
* Fixed false positive errors involving sub-type tests an `never` type
* Fixed miscompilation of multiple assignment statements (Fixes
https://github.com/Roblox/luau/issues/754)
* Type inference stability improvements
* Reduce the stack utilization of type checking.
* Improve the error message that's reported when a delimiting comma is
missing from a table literal. eg
```lua
local t = {
first = 1
second = 2
}```
* https://github.com/Roblox/luau/pull/719
* Improved `Failed to unify type packs` error message to be reported as
`Type pack 'X' could not be converted into 'Y'`
* https://github.com/Roblox/luau/pull/722
* 1% reduction in executed instruction count by removing a check in fast
call dispatch
* Additional fixes to reported error location of OOM errors in VM
* Improve `math.sqrt`, `math.floor` and `math.ceil` performance on
additional compilers and platforms (1-2% geomean improvement including
8-9% on math-cordic)
* All thrown exceptions by Luau analysis are derived from
`Luau::InternalCompilerError`
* When a call site has fewer arguments than required, error now reports
the location of the function name instead of the argument to the
function
* https://github.com/Roblox/luau/pull/724
* Fixed https://github.com/Roblox/luau/issues/725
Co-authored-by: Arseny Kapoulkine <arseny.kapoulkine@gmail.com>
Co-authored-by: Andy Friesen <afriesen@roblox.com>
* Support `["prop"]` syntax on class definitions in definition files.
(#704)
* Improve type checking performance for complex overloaded functions
* Fix rare cases of incorrect stack traces for out of memory errors at
runtime
* Reoptimized math.min/max/bit32 builtins assuming at least 2 arguments are used (1-2% lift on some benchmarks)
* Type errors that mention function types no longer have redundant parenthesis around return type
* Luau REPL now supports --compile=remarks which displays the source code with optimization remarks embedded as comments
* Builtin calls are slightly faster when called with 1-2 arguments (~1% improvement in some benchmarks)
- Fix rare type checking bugs with invalid generic types escaping the
module scope
- Fix type checking of variadic type packs in certain cases
- Implement type normalization, which resolves a large set of various
issues with unions/intersections in type checker
- Improve parse errors for trailing commas in function calls and type
lists
- Reduce profiling skew when using --profile with very high frequencies
- Improve performance of `lua_getinfo` (`debug.info`, `debug.traceback`
and profiling overhead are now 20% faster/smaller)
- Improve performance of polymorphic comparisons (1-2% lift on some
benchmarks)
- Improve performance of closure creation (1-2% lift on some benchmarks)
- Improve string comparison performance (4% lift on string sorting)
- Type aliases can no longer override primitive types; attempts to do
that will result in a type error
- Fix misleading type error messages for mismatches in expression list
length during assignment
- Fix incorrect type name display in certain cases
- setmetatable/getmetatable are now ~2x faster
- tools/perfstat.py can be used to display statistics about profiles
captured via --profile switch
To my understanding lua_cleartable does not need GC barriers because
it's only removing elements and not modifying the stack. But I'm not a
GC expert so please correct if I'm wrong.
resolves#672
Co-authored-by: Petri Häkkinen <petrih@rmd.remedy.fi>
- Improve type error messages for argument count mismatch in certain
cases
- Fix type checking variadic returns when the type is incompatible which
type checked in certain cases
- Reduce size of upvalue objects by 8 bytes on 64-bit platforms
- Reduce I$ footprint of interpreter by 1.5KB
- Reduce GC pause during atomic stage for programs with a lot of threads
- Remove support for bytecode v2
Luau currently has the following functions in the C API for dealing with
tables without invoking metamethods:
lua_rawgetfield
lua_rawget
lua_rawgeti
lua_rawset
lua_rawseti
This change adds the missing function lua_rawsetfield for consistency
and because it's more efficient to use it in place of plain lua_rawset
which requires pushing the key and value separately.
Co-authored-by: Petri Häkkinen <petrih@rmd.remedy.fi>
- Remove type definitions of
`utf8.nfcnormalize`/`nfdnormalize`/`graphemes` that aren't supported by
standalone Luau library
- Add `lua_costatus` to retrieve extended thread status (similar to
`coroutine.status`)
- Improve GC sweeping performance (2-10% improvement on allocation-heavy
benchmarks)
- Improve ComparisonPrecedence lint suggestions for three-way comparisons (X < Y < Z)
- Improve type checking stability
- Improve location information for errors when parsing invalid type annotations
- Compiler now generates bytecode version 3 in all configurations
- Improve performance of comparisons against numeric constants on AArch64
- Fix DeprecatedGlobal warning text in cases when the global is deprecated without a suggested alternative
- Fix an off-by-one error in type error text for incorrect use of string.format
- Reduce stack consumption further during parsing, hopefully eliminating stack overflows during parsing/compilation for good
- Mark interpolated string support as experimental (requires --fflags=LuauInterpolatedStringBaseSupport to enable)
- Simplify garbage collection treatment of upvalues, reducing cache misses during sweeping stage and reducing the cost of upvalue assignment (SETUPVAL); supersedes #643
- Simplify garbage collection treatment of sleeping threads
- Simplify sweeping of alive threads, reducing cache misses during sweeping stage
- Simplify management of string buffers, removing redundant linked list operations
- Fix autocomplete not suggesting globals defined after the cursor (fixes#622)
- Improve type checker stability
- Reduce parser C stack consumption which fixes some stack overflow crashes on deeply nested sources
- Improve performance of bit32.extract/replace when width is implied (~3% faster chess)
- Improve performance of bit32.extract when field/width are constants (~10% faster base64)
- Heap dump now annotates thread stacks with local variable/function names
In case a large userdata size is passed to lua_newuserdatadtor it might overflow the size resulting in luaU_newudata actually allocating the object without a memory error. This will then result in overwriting part of the metatable pointer of the userdata.
This PR fixes this issue by checking for the overflow and in such cases pass a size value which will cause a memory error in luaU_newudata.
* Fix free Luau type being fully overwritten by 'any' and causing UAF
* Fix lua_clonefunction implementation replacing top instead of pushing
* Falsey values other than false can now narrow refinements
* Fix lua_getmetatable, lua_getfenv not waking thread up
* FIx a case where lua_objlen could push a new string without thread wakeup or GC
* Moved Luau math and bit32 definitions to definition file
* Improve Luau parse recovery of incorrect return type token
* Run clang-format
* Contains a preliminary implementation of deferred constraint resolution
* Reduce stack usage by some recursive functions
* Fix a bug when smartCloning a BoundTypeVar
* Remove some GC related flags from VM
* Adds a currently unused x86-64 assembler as a prerequisite for possible future JIT compilation
* Fix a bug in table iteration (closes Possible table iteration bug #504)
* Improved warning method when function is used as a type
* Fix a bug with unsandboxed iteration with pairs()
* Type of coroutine.status() is now a union of value types
* Bytecode output for tests/debugging now has labels
* Improvements to loop unrolling cost estimation
* Report errors when the key obviously doesn't exist in the table
