# New Type Solver
- Implement bidirectional type inference for higher order functions so
that we can provide a more precise type improving the autocomplete's
human factors.
- We seal all tables, so we changed the stringification to make it a
little lighter on users.
- Fixed a case of array-out-of-bound access.
- Type families no longer depends on `TxnLog` and `Unifier`.
- Type refinements now waits until the free types are sufficiently
solved.
# Native Code Generation
- Remove cached slot lookup for `executeSETTABLEKS` function because it
is a fallback in the event of a cache miss, making the cached slot
lookup redundant.
- Optimized repeated array lookups, e.g. `a[3]` in `a[3] = a[3] / 2` is
done once.
# Misc
- On some platforms, it is necessary to use `gmtime_s` with the
arguments reversed to get the current time. You can now define
`DOCTEST_CONFIG_USE_GMTIME_S` to build and run unit tests on those
platforms.
---------
Co-authored-by: Arseny Kapoulkine <arseny.kapoulkine@gmail.com>
Co-authored-by: Vyacheslav Egorov <vegorov@roblox.com>
Co-authored-by: Andy Friesen <afriesen@roblox.com>
Co-authored-by: Lily Brown <lbrown@roblox.com>
Co-authored-by: Aaron Weiss <aaronweiss@roblox.com>
- Cleaned up `FFlag::FixFindBindingAtFunctionName`,
`FFlag::LuauNormalizeBlockedTypes`, `FFlag::LuauPCallDebuggerFix`
- Added support for break and continue into control flow analysis
- The old type unification engine will now report a more fine-grained
error at times, indicating that type normalization in particular failed
# New Type Solver
- Refactor of Unifier2, the new unification implementation for Luau
- Completed MVP of new unification implementation
- Dramatically simplified overload selection logic
- Type family reduction can now apply sooner to free types that have
been solved
- Subtyping now supports table indexers
- Generalization now replaces bad generics with unknown
# Native Code Generation
- Reduce stack spills caused by FINDUPVAL and STORE_TAG
- Improve Generate SHL/SHR/SAR/rotates with immediate operands in X64
- Removed redundant case re-check in table lookup fallback
---------
Co-authored-by: Arseny Kapoulkine <arseny.kapoulkine@gmail.com>
Co-authored-by: Vyacheslav Egorov <vegorov@roblox.com>
Co-authored-by: Andy Friesen <afriesen@roblox.com>
Co-authored-by: Lily Brown <lbrown@roblox.com>
Fixes: https://github.com/Roblox/luau/issues/913
This PR adds support for type refinements around guard clauses that use
`break` and `continue` statements inside a loop, similar to how guard
clauses with `return` is supported.
I had some free time today, so I figure I'd give a shot at a naïve fix
for this at the very least.
---
## Resulting Change:
Luau now supports type refinements within loops where a `continue` or
`break` guard clause was used.
For example:
```lua
for _, object in objects :: {{value: string?}} do
if not object.value then
continue
end
local x: string = object.value -- OK; Used to emit "Type 'string?' could not be converted into 'string'"
end
```
---------
Co-authored-by: Alexander McCord <amccord@roblox.com>
* Rerun clang-format on the code
* Fix the variance on indexer result subtyping. This fixes some issues
with inconsistent error reporting.
* Fix a bug in the normalization logic for intersections of strings
New Type Solver
* New overload selection logic
* Subtype tests now correctly treat a generic as its upper bound within
that generic's scope
* Semantic subtyping for negation types
* Semantic subtyping between strings and compatible table types like
`{lower: (string) -> string}`
* Further work toward finalizing our new subtype test
* Correctly generalize module-scope symbols
Native Codegen
* Lowering statistics for assembly
* Make executable allocation size/limit configurable without a rebuild.
Use `FInt::LuauCodeGenBlockSize` and `FInt::LuauCodeGenMaxTotalSize`.
---------
Co-authored-by: Arseny Kapoulkine <arseny.kapoulkine@gmail.com>
Co-authored-by: Vyacheslav Egorov <vegorov@roblox.com>
Co-authored-by: Lily Brown <lbrown@roblox.com>
* Fixed `Frontend::markDirty` not working on modules that were not
typechecked yet
* Fixed generic variadic function unification succeeding when it should
have reported an error
New Type Solver:
* Implemented semantic subtyping check for function types
Native Code Generation:
* Improved performance of numerical loops with a constant step
* Simplified IR for `bit32.extract` calls extracting first/last bits
* Improved performance of NaN checks
CLI/Reduce.cpp:
Never worked under MinGW as-is. Add check for MinGW as they're defined.
VM/src/lmem.cpp:
MinGW layout follows more closely MSVC. Checks before were only correct
for 32-bit gcc / clang in non-Windows.
NOTES:
__MINGW32__ is defined on both 32-bit and 64-bit, __MINGW64__ is 64-bit
only. 32-bit MinGW compilers (both Clang & GCC) have a floating point
test error on math.noise, specifically math.lua:258. All other test
cases / unit tests pass modulo stack size issues (so requires optimized build).
---------
Co-authored-by: jdp_ <42700985+jdpatdiscord@users.noreply.github.com>
- Updated Roblox copyright to 2023
- Floor division operator `//` (implements #832)
- Autocomplete now shows `end` within `do` blocks
- Restore BraceType when using `Lexer::lookahead` (fixes#1019)
# New typechecker
- Subtyping tests between metatables and tables
- Subtyping tests between string singletons and tables
- Subtyping tests for class types
# Native codegen
- Fixed macOS test failure (wrong spill restore offset)
- Fixed clobbering of non-volatile xmm registers on Windows
- Fixed wrong storage location of SSA reg spills
- Implemented A64 support for add/sub extended
- Eliminated zextReg from A64 lowering
- Remove identical table slot lookups
- Propagate values from predecessor into the linear block
- Disabled reuse slot optimization
- Keep `LuaNode::val` check for nil when optimizing `CHECK_SLOT_MATCH`
- Implemented IR translation of `table.insert` builtin
- Fixed mmap error handling on macOS/Linux
# Tooling
- Used `|` as a column separator instead of `+` in `bench.py`
- Added a `table.sort` micro-benchmark
- Switched `libprotobuf-mutator` to a less problematic version
* AST queries at position where function name is will now return
AstExprLocal
* Lexer performance has been slightly improved
* Fixed incorrect string singleton autocomplete suggestions (fixes#858)
* Improved parsing error messages
* Fixed crash on null pointer access in unification (fixes#1017)
* Native code support is enabled by default and `native=1`
(make)/`LUAU_NATIVE` (CMake)/`-DLUA_CUSTOM_EXECUTION` configuration is
no longer required
New typechecker:
* New subtyping check can now handle generic functions and tables
(including those that contain cycles)
Native code generation:
* Loops with non-numeric parameters are now handled by VM to streamline
native code
* Array size check can be optimized away in SETLIST
* On failure, CodeGen::compile returns a reason
* Fixed clobbering of non-volatile xmm registers on Windows
* Fix a use-after-free bug in the new type cloning algorithm
* Tighten up the type of `coroutine.wrap`. It is now `<A..., R...>(f:
(A...) -> R...) -> ((A...) -> R...)`
* Break `.luaurc` out into a separate library target `Luau.Config`. This
makes it easier for applications to reason about config files without
also depending on the type inference engine.
* Move typechecking limits into `FrontendOptions`. This allows embedders
more finely-grained control over autocomplete's internal time limits.
* Fix stability issue with debugger onprotectederror callback allowing
break in non-yieldable contexts
New solver:
* Initial work toward [Local Type
Inference](0e1082108f/rfcs/local-type-inference.md)
* Introduce a new subtyping test. This will be much nicer than the old
test because it is completely separate both from actual type inference
and from error reporting.
Native code generation:
* Added function to compute iterated dominance frontier
* Optimize barriers in SET_UPVALUE when tag is known
* Cache lua_State::global in a register on A64
* Optimize constant stores in A64 lowering
* Track table array size state to optimize array size checks
* Add split tag/value store into a VM register
* Check that spills can outlive the block only in specific conditions
---------
Co-authored-by: Arseny Kapoulkine <arseny.kapoulkine@gmail.com>
Co-authored-by: Vyacheslav Egorov <vegorov@roblox.com>
* Better indentation in multi-line type mismatch error messages
* Error message clone can no longer cause a stack overflow (when
typechecking with retainFullTypeGraphs set to false); fixes
https://github.com/Roblox/luau/issues/975
* `string.format` with %s is now ~2x faster on strings smaller than 100
characters
Native code generation:
* All VM side exits will block return to the native execution of the
current function to preserve correctness
* Fixed executable page allocation on Apple platforms when using
hardened runtime
* Added statistics for code generation (no. of functions compiler,
memory used for different areas)
* Fixed issue with function entry type checks performed more that once
in some functions
Nobody is maintaining this and we haven't really used it and are
unlikely to start due to a high degree of noise and lack of dedicated
machines for this setup. Callgrind has worked for us well enough, with
additional profiling performed locally by engineers - this is not
perfect but it doesn't look like we have a path to making this better.
* 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>
Type checker/autocomplete:
* `Luau::autocomplete` no longer performs typechecking internally, make
sure to run `Frontend::check` before performing autocomplete requests
* Autocomplete string suggestions without "" are now only suggested
inside the ""
* Autocomplete suggestions now include `function (anonymous autofilled)`
key with a full suggestion for the function expression (with arguments
included) stored in `AutocompleteEntry::insertText`
* `AutocompleteEntry::indexedWithSelf` is provided for function call
suggestions made with `:`
* Cyclic modules now see each other type exports as `any` to prevent
memory use-after-free (similar to module return type)
Runtime:
* Updated inline/loop unroll cost model to better handle assignments
(Fixes https://github.com/Roblox/luau/issues/978)
* `math.noise` speed was improved by ~30%
* `table.concat` speed was improved by ~5-7%
* `tonumber` and `tostring` now have fastcall paths that execute ~1.5x
and ~2.5x faster respectively (fixes#777)
* Fixed crash in `luaL_typename` when index refers to a non-existing
value
* Fixed potential out of memory scenario when using `string.sub` or
`string.char` in a loop
* Fixed behavior of some fastcall builtins when called without arguments
under -O2 to match original functions
* Support for native code execution in VM is now enabled by default
(note: native code still has to be generated explicitly)
* `Codegen::compile` now accepts `CodeGen_OnlyNativeModules` flag. When
set, only modules that have a `--!native` hot-comment at the top will be
compiled to native code
In our new typechecker:
* Generic type packs are no longer considered to be variadic during
unification
* Timeout and cancellation now works in new solver
* Fixed false positive errors around 'table' and 'function' type
refinements
* Table literals now use covariant unification rules. This is sound
since literal has no type specified and has no aliases
* Fixed issues with blocked types escaping the constraint solver
* Fixed more places where error messages that should've been suppressed
were still reported
* Fixed errors when iterating over a top table type
In our native code generation (jit):
* 'DebugLuauAbortingChecks' flag is now supported on A64
* LOP_NEWCLOSURE has been translated to IR
Gentoo recently added Luau to their official overlay (the term they use
to describe their package repository) and it would only be appropriate
to include that detail here.
It may as well also be the first distribution to *officially* package
it, given the maintainer is one of Gentoo's own.
Signed-off-by: Sebastian France <MagelessMayhem@protonmail.com>
* Added support for async typechecking cancellation using a token passed
through frontend options
* Added luaC_enumheap for building debug tools that need a graph of Luau
heap
In our new typechecker:
* Errors or now suppressed when checking property lookup of
error-suppressing unions
In our native code generation (jit):
* Fixed unhandled value type in NOT_ANY lowering
* Fast-call tag checks will exit to VM on failure, instead of relying on
a native fallback
* Added vector type to the type information
* Eliminated redundant direct jumps across dead blocks
* Debugger APIs are now disabled for call frames executing natively
* Implemented support for unwind registration on macOS 14
* Fixed indexing table intersections using `x["prop"]` syntax:
https://github.com/Roblox/luau/pull/971
* Add console output codepage for Windows:
https://github.com/Roblox/luau/pull/967
* Added `Frontend::parse` for a fast source graph preparation
* luau_load should check GC
* Work toward a type-diff system for nicer error messages
New Solver
* Correctly suppress errors in more cases
* Further improvements to typechecking of function calls and return
statements
* Crash fixes
* Propagate refinements drawn from the condition of a while loop into
the loop body
JIT
* Fix accidental bailout for math.frexp/modf/sign in A64
* Work toward bringing type annotation info in
* Do not propagate Luau IR constants of wrong type into load
instructions
* CHECK_SAFEENV exits to VM on failure
* Implement error handling in A64 reg allocator
* Inline the string.len builtin
* Do not enter native code of a function if arguments don’t match
---------
Co-authored-by: Arseny Kapoulkine <arseny.kapoulkine@gmail.com>
Co-authored-by: Vyacheslav Egorov <vegorov@roblox.com>
Previously unicode codepoints would be incorrectly shown in windows
terminals, such as with u2503(┃):
```ps
❯ "print('\u{2503}')" | luau.exe
Γöâ
```
This change fixes the issue by setting the console's codepage on
windows, resulting in fixed behaviour:
```ps
❯ "print('\u{2503}')" | luau.exe
┃
```
Right now, you can index an intersection of tables fine when using
`x.prop` syntax, but not when using `x["prop"]` syntax.
This fixes it for the latter case
```lua
type Foo = {
Bar: string,
} & { Baz: number }
local x: Foo = { Bar = "1", Baz = 2 }
local y = x["Bar"] -- TypeError: Expected type table, got '{| Bar: string |} & {| Baz: number |}' instead
```
Part of a fix to
https://github.com/Roblox/luau/issues/533#issuecomment-1291779353
* Optimized operations like instantiation and module export for very
large types
In our new typechecker:
* Typechecking of function calls was rewritten to handle more cases
correctly
* Fixed a crash that can happen after self-referential type is exported
from a module
* Fixed a false positive error in string comparison
* Added handling of `for...in` variable type annotations and fixed
issues with the iterator call inside
* Self-referential 'hasProp' and 'setProp' constraints are now handled
correctly
In our native code generation (jit):
* Added '--target' argument to luau-compile to test multiple
architectures different from host architecture
* GC barrier tag check is skipped if type is already known to be
GC-collectable
* Added GET_TYPE/GET_TYPEOF instructions for type/typeof fast-calls
* Improved code size of interrupt handlers on X64
* Definition files can now ascribe indexers to class types.
(https://github.com/Roblox/luau/pull/949)
* Remove --compile support from the REPL. You can just use luau-compile
instead.
* When an exception is thrown during parallel typechecking (usually an
ICE), we now gracefully stop typechecking and drain active workers
before rethrowing the exception.
New solver
* Include more source location information when we hit an internal
compiler error
* Improve the logic that simplifies intersections of tables
JIT
* Save testable type annotations to bytecode
* Improve block placement for linearized blocks
* Add support for lea reg, [rip+offset] for labels
* Unify X64 and A64 codegen for RETURN
* Outline interrupt handlers for X64
* Remove global rArgN in favor of build.abi
* Change A64 INTERRUPT lowering to match X64
---------
Co-authored-by: Arseny Kapoulkine <arseny.kapoulkine@gmail.com>
Co-authored-by: Vyacheslav Egorov <vegorov@roblox.com>
The existing instruction is incorrect, the luau package exists on the
Arch Linux User Repository (AUR), not at the official repository.
Feel free to suggest edits if something is wrong/missing, thanks!
(I also have a pkgbuild that builds every executable possible excluding
tests (repl, analyze, ast, reduce), however I did not include this since
releases only include repl and analyze)
* Added luau-compile executable target to build/test compilation without
having full REPL included.
In our new typechecker:
* Fixed the order in which constraints are checked to get more
deterministic errors in different environments
* Fixed `isNumber`/`isString` checks to fix false positive errors in
binary comparisons
* CannotCallNonFunction error is reported when calling an intersection
type of non-functions
In our native code generation (jit):
* Outlined X64 return instruction code to improve code size
* Improved performance of return instruction on A64
* Added construction of a dominator tree for future optimizations
We haven't updated this document in a while and yet there was a fair
amount of performance work, some of which can be documented here.
Note that this is not fully comprehensive in that it excludes a lot of
internal tuning that is difficult to describe other than with "we made
things faster".
Fixes#935:
* String literals that include `\z` escape sequence followed by newline
characters are now correctly highlighted.
* Unescaped backslash (`\`) character at the end of the line no longer
acts like the `\z` escape sequence inside string literals when
highlighting.
A pretty small changelist this week:
* When type inference fails to find any matching overload for a
function, we were declining to commit any changes to the type graph at
all. This was resulting in confusing type errors in certain cases. Now,
when a matching overload cannot be found, we always commit to the first
overload we tried.
JIT
* Fix missing variadic register invalidation in FALLBACK_GETVARARGS
* Add a missing null pointer check for the result of luaT_gettm
---------
Co-authored-by: Arseny Kapoulkine <arseny.kapoulkine@gmail.com>
Co-authored-by: Vyacheslav Egorov <vegorov@roblox.com>
* Fixed gcc warning about uninitialized `std::optional`
* Fixed inlining of functions when they are used to compute their own
arguments
In the new type solver:
* Type families that are not part of a function signature cannot be
resolved at instantiation time and will now produce an error. This will
be relaxed in the future when we get constraint clauses on function
signatures (internally)
* `never` type is now comparable
* Improved typechecking of `for..in` statements
* Fixed checks for number type in `Add` type family
* Performance was improved, with particularly large gains on large
projects
And in native code generation (jit):
* We eliminated the call instruction overhead when native code support
is enabled in the VM
* Small optimizations to arm64 lowering
* Reworked LOP_GETIMPORT handling to reduce assembly code size
* Fixed non-deterministic binary output
* Fixed bad code generation caused by incorrect SSA to VM register links
invalidation
---------
Co-authored-by: Arseny Kapoulkine <arseny.kapoulkine@gmail.com>
Co-authored-by: Andy Friesen <afriesen@roblox.com>
Lots of things going on this week:
* Fix a crash that could occur in the presence of a cyclic union. We
shouldn't be creating cyclic unions, but we shouldn't be crashing when
they arise either.
* Minor cleanup of `luau_precall`
* Internal change to make L->top handling slightly more uniform
* Optimize SETGLOBAL & GETGLOBAL fallback C functions.
* https://github.com/Roblox/luau/pull/929
* The syntax to the `luau-reduce` commandline tool has changed. It now
accepts a script, a command to execute, and an error to search for. It
no longer automatically passes the script to the command which makes it
a lot more flexible. Also be warned that it edits the script it is
passed **in place**. Do not point it at something that is not in source
control!
New solver
* Switch to a greedier but more fallible algorithm for simplifying union
and intersection types that are created as part of refinement
calculation. This has much better and more predictable performance.
* Fix a constraint cycle in recursive function calls.
* Much improved inference of binary addition. Functions like `function
add(x, y) return x + y end` can now be inferred without annotations. We
also accurately typecheck calls to functions like this.
* Many small bugfixes surrounding things like table indexers
* Add support for indexers on class types. This was previously added to
the old solver; we now add it to the new one for feature parity.
JIT
* https://github.com/Roblox/luau/pull/931
* Fuse key.value and key.tt loads for CEHCK_SLOT_MATCH in A64
* Implement remaining aliases of BFM for A64
* Implement new callinfo flag for A64
* Add instruction simplification for int->num->int conversion chains
* Don't even load execdata for X64 calls
* Treat opcode fallbacks the same as manually written fallbacks
---------
Co-authored-by: Arseny Kapoulkine <arseny.kapoulkine@gmail.com>
Co-authored-by: Vyacheslav Egorov <vegorov@roblox.com>
