* `table.sort` was improved further. It now guarentees N*log(N) time
complexity in the worst case.
* Fix https://github.com/Roblox/luau/issues/880
We are also working on fixing final bugs and crashes in the new type
solver.
On the CodeGen front we have a few things going on:
* We have a smarter register allocator for the x86 JIT
* We lower more instructions on arm64
* The vector constructor builtin is now translated to IR
---------
Co-authored-by: Arseny Kapoulkine <arseny.kapoulkine@gmail.com>
Co-authored-by: Vyacheslav Egorov <vegorov@roblox.com>
Once again, all of our changes this week are for new type solver and the
JIT.
In the new type solver, we fixed cyclic type alias handling and multiple
stability issues.
In the JIT, our main progress was for arm64, where, after lowering 36%
of instructions, we start seeing first Luau functions executing
natively.
For x64, we performed code cleanup and refactoring to allow for future
optimizations.
* A small subset of control-flow refinements have been added to
recognize type options that are unreachable after a
conditional/unconditional code block. (Fixes
https://github.com/Roblox/luau/issues/356).
Some examples:
```lua
local function f(x: string?)
if not x then return end
-- x is 'string' here
end
```
Throwing calls like `error` or `assert(false)` instead of 'return' are
also recognized.
Existing complex refinements like type/typeof and tagged union checks
are expected to work, among others.
To enable this feature, `LuauTinyControlFlowAnalysis` exclusion has to
be removed from `ExperimentalFlags.h`.
If will become enabled unconditionally in the near future.
* Linter has been integrated into the typechecker analysis so that
type-aware lint warnings can work in any mode
`Frontend::lint` methods were deprecated, `Frontend::check` has to be
used instead with `runLintChecks` option set.
Resulting lint warning are located inside `CheckResult`.
* Fixed large performance drop and increased memory consumption when
array is filled at an offset (Fixes
https://github.com/Roblox/luau/issues/590)
* Part of [Type error suppression
RFC](https://github.com/Roblox/luau/blob/master/rfcs/type-error-suppression.md)
was implemented making subtyping checks with `any` type transitive.
---
In our work on the new type-solver:
* `--!nocheck` mode no longer reports type errors
* New solver will not be used for `--!nonstrict` modules until all
issues with strict mode typechecking are fixed
* Added control-flow aware type refinements mentioned earlier
In native code generation:
* `LOP_NAMECALL` has been translated to IR
* `type` and `typeof` builtin fastcalls have been translated to
IR/assembly
* Additional steps were taken towards arm64 support
* Fix#817
* Fix#850
* Optimize math.floor/ceil/round with SSE4.1
* Results in a ~7-9% speedup on the math-cordic benchmark.
* Optimized table.sort.
* table.sort is now ~4.1x faster (when not using a predicate) and ~2.1x
faster when using a simple predicate. Performance may improve further in
the future.
* Reorganize the memory ownership of builtin type definitions.
* This is a small initial step toward affording parallel typechecking.
The new type solver is coming along nicely. We are working on fixing
crashes and bugs.
A few major changes to native codegen landed this week:
* Fixed lowering of Luau IR mod instruction when first argument is a
constant
* Added VM register data-flow/capture analysis
* Fixed issues with optimizations in unreachable blocks
---------
Co-authored-by: Arseny Kapoulkine <arseny.kapoulkine@gmail.com>
Co-authored-by: Vyacheslav Egorov <vegorov@roblox.com>
* Fixed incorrect lexeme generated for string parts in the middle of an
interpolated string (Fixes https://github.com/Roblox/luau/issues/744)
* DeprecatedApi lint can report some issues without type inference
information
* Fixed performance of autocomplete requests when suggestions have large
intersection types (Solves
https://github.com/Roblox/luau/discussions/847)
* Marked `table.getn`/`foreach`/`foreachi` as deprecated ([RFC:
Deprecate
table.getn/foreach/foreachi](https://github.com/Roblox/luau/blob/master/rfcs/deprecate-table-getn-foreach.md))
* With -O2 optimization level, we now optimize builtin calls based on
known argument/return count.
Note that this change can be observable if `getfenv/setfenv` is used to
substitute a builtin, especially if arity is different.
Fastcall heavy tests show a 1-2% improvement.
* Luau can now be built with clang-cl (Fixes
https://github.com/Roblox/luau/issues/736)
We also made many improvements to our experimental components.
For our new type solver:
* Overhauled data flow analysis system, fixed issues with 'repeat'
loops, global variables and type annotations
* Type refinements now work on generic table indexing with a string
literal
* Type refinements will properly track potentially 'nil' values (like
t[x] for a missing key) and their further refinements
* Internal top table type is now isomorphic to `{}` which fixes issues
when `typeof(v) == 'table'` type refinement is handled
* References to non-existent types in type annotations no longer resolve
to 'error' type like in old solver
* Improved handling of class unions in property access expressions
* Fixed default type packs
* Unsealed tables can now have metatables
* Restored expected types for function arguments
And for native code generation:
* Added min and max IR instructions mapping to vminsd/vmaxsd on x64
* We now speculatively extract direct execution fast-paths based on
expected types of expressions which provides better optimization
opportunities inside a single basic block
* Translated existing math fastcalls to IR form to improve tag guard
removal and constant propagation
* Fix a bug where reading a property from an unsealed table caused
inference to improperly infer the existence of that property.
* Fix#827
We have also made a lot of progress on the new solver and the JIT. Both
projects are still in the process of being built out. Neither are ready
for general use yet.
We are mostly working to tighten up how the new solver handles
refinements and updates to unsealed tables to bring it up to the same
level as the old solver.
---------
Co-authored-by: Arseny Kapoulkine <arseny.kapoulkine@gmail.com>
Co-authored-by: Vyacheslav Egorov <vegorov@roblox.com>
* For autocomplete, additional information is included in Scope for type
alias name locations and names of imported modules
* Improved autocomplete suggestions in 'for' and 'while' loop headers
* String match functions return types are now optional strings and
numbers because match is not guaranteed at runtime
* Fixed build issue on gcc 11 and up (Fixes
https://github.com/Roblox/luau/issues/806)
* Fixed garbage data in module scopes when type graph is not retained
* LOP_MOVE with the same source and target registers is no longer
generated (Fixes https://github.com/Roblox/luau/issues/793)
* Fixed unions of `nil` types displaying as `?`
* Internal normalization now handles class types which can make
previously failing (incorrectly) sub-typing checks to succeed
* 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
* Type inference of `a and b` and `a or b` has been improved (Fixes
https://github.com/Roblox/luau/issues/730)
* Improved error message when `for ... in x` loop iterates over a value
that could be 'nil'
* Return type of `next` not includes 'nil' (Fixes
https://github.com/Roblox/luau/issues/706)
* Improved type inference of `string` type
* Luau library table type names are now reported as `typeof(string)`/etc
instead of just `string` which was misleading
* Added parsing error when optional type alias type parameter wasn't
provided after `=` token
* Improved tagged union type refinement in conditional expressions, type
in `else` branch should no longer include previously handled union
options
* 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
}```
* 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
- 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
Implements the string interpolation RFC (#165).
Adds the string interpolation as per the RFC.
```lua
local name = "world"
print(`Hello {name}!`) -- Hello world!
```
Co-authored-by: Arseny Kapoulkine <arseny.kapoulkine@gmail.com>
Co-authored-by: Alexander McCord <11488393+alexmccord@users.noreply.github.com>
* 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
- Improve refinement support for unions, in particular it's now possible to implement tagged unions as a union of tables where individual branches use a string literal type for one of the fields.
- Fix `string.split` type information
- Optimize `select(_, ...)` to run in constant time (~2.7x faster on VariadicSelect benchmark)
- Improve debug line information for multi-line assignments
- Improve compilation of table literals when table keys are constant expressions/variables
- Use forward GC barrier for `setmetatable` which slightly accelerates GC progress
- TableOperations lint now includes a warning for table.create(N, {}) (which is likely a mistake since the table is shared by all entries)
- Type checker now type checks #v when v is a union
- Parser now rejects sources that consists of a single unfinished long comment
- Work around significant MSVC 2022 performance regression, bringing it more or less in line with MSVC 2019
- Compiler now predicts array size for newly allocated tables when the table is filled in a short loop
- Small improvements in compilation throughput (~2% faster)
- Implement paged sweeper for GC which improves sweep throughput 2-3x and reduces memory consumption by 8 bytes per object (once it is stabilized we will see additional 8 bytes per object of savings)
- Improve Repl Tab completion
- Repl now supports -i (interactive mode to run code in context of a script's environment) and -On (to control optimization flags)
- Rework transaction log used for type checking which should result in more robust type checking internals with fewer bugs
- Reduce the amount of memory consumed by type checker on large module graphs
- Type checker now errors on attempts to change the type of imported module fields
- The return type of newproxy is now any (fixes#296)
- Implement new number printing algorithm (Schubfach) which makes tostring() produce precise (round-trippable) and short decimal output up to 10x faster
- Fix lua_Debug::linedefined to point to the line with the function definition instead of the first statement (fixes#265)
- Fix minor bugs in Tab completion in Repl
- Repl now saves/restores command history in ~/.luau_history
This doesn't contain all changes for 507 yet but we might want to do the
Luau 0.507 release a bit earlier to end the year sooner.
Changes:
- Type ascription (::) now permits casts between related types in both directions, allowing to refine or loosen the type (RFC #56)
- Fix type definition for tonumber to return number? since the input string isn't guaranteed to contain a valid number
- Fix type refinements for field access via []
- Many stability fixes for type checker
- Provide extra information in error messages for type mismatches in more cases
- Improve performance of type checking for large unions when union members are string literals
- Add coverage reporting support to Repl (--coverage command line argument) and lua_getcoverage C API
- Work around code signing issues during Makefile builds on macOS
- Improve performance of truthiness checks in some cases, particularly on Apple M1, resulting in 10-25% perf gains on qsort benchmark depending on the CPU/compiler
- Fix support for little-endian systems; IBM s390x here we go!
- Fix some cases where type checking would overflow the native stack
- Improve autocomplete behavior when assigning a partially written function call (not currently exposed through command line tools)
- Improve autocomplete type inference feedback for some expressions where previously the type would not be known
- Improve quantification performance during type checking for large types
- Improve type checking for table literals when the expected type of the table is known because of a type annotation
- Fix type checking errors in cases where required module has errors in the resulting type
- Fix debug line information for multi-line chained call sequences (Add function name information for "attempt to call a nil value" #255)
- lua_newuserdata now takes 2 arguments to match Lua/LuaJIT APIs better; lua_newuserdatatagged should be used if the third argument was non-0.
- lua_ref can no longer be used with LUA_REGISTRYINDEX to prevent mistakes when migrating Lua FFI (Inconsistency with lua_ref #247)
- Fix assertions and possible crashes when executing script code indirectly via metatable dispatch from lua_equal/lua_lessthan/lua_getfield/etc. (Hitting a crash in an assert after lua_equal is called. #259)
- Fix flamegraph scripts to run under Python 2
- Improve error recovery during type checking
- Initial (not fully complete) implementation for singleton types (RFC RFC: Singleton types #37)
- Implement a C-friendly interface for compiler (luacode.h)
- Remove C++ features from lua.h (removed default arguments from luau_load and lua_pushcfunction)
- Fix lua_breakpoint behavior when enabled=false
- Implement coroutine.close (RFC RFC: coroutine.close #88)
Note, this introduces small breaking changes in lua.h:
- luau_load env argument is now required, pass an extra 0
- lua_pushcfunction now must be called with 3 arguments; if you were calling it with 2 arguments, pass an extra NULL; if you were calling it with 4, use lua_pushcclosure.
These changes are necessary to make sure lua.h can be used from pure C - the future release will make it possible by adding an option to luaconf.h to change function name mangling to be C-compatible. We don't anticipate breaking the FFI interface in the future, but this change was necessary to restore C compatibility.
Closes#121Fixes#213
- Type mismatch errors now show detailed information for compound types, highlighting the mismatching component
- Fix string.pack bug on ARM when packing negative numbers using unsigned formats
- Implement bit32.countlz/countrz (RFC RFC: bit32.countlz/countrz #89)
- Minor compiler throughput optimization (~2% faster compilation)
- Improve transpiler behavior for edge cases and better test coverage (not exposed through CLI at the moment)
- Improve error recovery when parsing invalid assignments
- Build fixes for fuzzing targets
- A series of major optimizations to type checking performance on complex
programs/types (up to two orders of magnitude speedup for programs
involving huge tagged unions)
- Fix a few issues encountered by UBSAN (and maybe fix s390x builds)
- Fix gcc-11 test builds
- Fix a rare corner case where luau_load wouldn't wake inactive threads
which could result in a use-after-free due to GC
- Fix CLI crash when error object that's not a string escapes to top level
- Fix Makefile suffixes on macOS
Co-authored-by: Rodactor <rodactor@roblox.com>
Changes:
- Support for time tracing for analysis/compiler (not currently exposed
through CLI)
- Support for type pack arguments in type aliases (#83)
- Basic support for require(path) in luau-analyze
- Add a lint warning for table.move with 0 index as part of
TableOperation lint
- Remove last STL dependency from Luau.VM
- Minor VS2022 performance tuning
Co-authored-by: Rodactor <rodactor@roblox.com>
Andy Friesen