mirror of
https://github.com/luau-lang/luau.git
synced 2024-12-13 21:40:43 +00:00
2173938eb0
This change adds support for tagged lightuserdata and optional custom typenames for lightuserdata. Background: Lightuserdata is an efficient representation for many kinds of unmanaged handles and resources in a game engine. However, currently the VM only supports one kind of lightuserdata, which makes it problematic in practice. For example, it's not possible to distinguish between different kinds of lightuserdata in Lua bindings, which can lead to unsafe practices and even crashes when a wrong kind of lightuserdata is passed to a binding function. Tagged lightuserdata work similarly to tagged userdata, i.e. they allow checking the tag quickly using lua_tolightuserdatatagged (or lua_lightuserdatatag). The tag is stored in the 'extra' field of TValue so it will add no cost to the (untagged) lightuserdata type. Alternatives would be to use full userdata values or use bitpacking to embed type information into lightuserdata on application level. Unfortunately these options are not that great in practice: full userdata have major performance implications and bitpacking fails in cases where full 64 bits are already used (e.g. pointers or 64-bit hashes). Lightuserdata names are not strictly necessary but they are rather convenient when debugging Lua code. More precise error messages and tostring returning more specific typename are useful to have in practice (e.g. "resource" or "entity" instead of the more generic "userdata"). Impl note: I did not add support for renaming tags in lua_setlightuserdataname as I'm not sure if it's possible to free fixed strings. If it's simple enough, maybe we should allow renaming (although I can't think of a specific need for it)? --------- Co-authored-by: Petri Häkkinen <petrih@rmd.remedy.fi>
150 lines
4.7 KiB
C
150 lines
4.7 KiB
C
// This file is part of the Luau programming language and is licensed under MIT License; see LICENSE.txt for details
|
|
// This code is based on Lua 5.x implementation licensed under MIT License; see lua_LICENSE.txt for details
|
|
#pragma once
|
|
|
|
// When debugging complex issues, consider enabling one of these:
|
|
// This will reallocate the stack very aggressively at every opportunity; use this with asan to catch stale stack pointers
|
|
// #define HARDSTACKTESTS 1
|
|
// This will call GC validation very aggressively at every incremental GC step; use this with caution as it's SLOW
|
|
// #define HARDMEMTESTS 1
|
|
// This will call GC validation very aggressively at every GC opportunity; use this with caution as it's VERY SLOW
|
|
// #define HARDMEMTESTS 2
|
|
|
|
// To force MSVC2017+ to generate SSE2 code for some stdlib functions we need to locally enable /fp:fast
|
|
// Note that /fp:fast changes the semantics of floating point comparisons so this is only safe to do for functions without ones
|
|
#if defined(_MSC_VER) && !defined(__clang__)
|
|
#define LUAU_FASTMATH_BEGIN __pragma(float_control(precise, off, push))
|
|
#define LUAU_FASTMATH_END __pragma(float_control(pop))
|
|
#else
|
|
#define LUAU_FASTMATH_BEGIN
|
|
#define LUAU_FASTMATH_END
|
|
#endif
|
|
|
|
// Some functions like floor/ceil have SSE4.1 equivalents but we currently support systems without SSE4.1
|
|
// Note that we only need to do this when SSE4.1 support is not guaranteed by compiler settings, as otherwise compiler will optimize these for us.
|
|
#if (defined(__x86_64__) || defined(_M_X64)) && !defined(__SSE4_1__) && !defined(__AVX__)
|
|
#if defined(_MSC_VER) && !defined(__clang__)
|
|
#define LUAU_TARGET_SSE41
|
|
#elif defined(__GNUC__) && defined(__has_attribute)
|
|
#if __has_attribute(target)
|
|
#define LUAU_TARGET_SSE41 __attribute__((target("sse4.1")))
|
|
#endif
|
|
#endif
|
|
#endif
|
|
|
|
// Used on functions that have a printf-like interface to validate them statically
|
|
#if defined(__GNUC__)
|
|
#define LUA_PRINTF_ATTR(fmt, arg) __attribute__((format(printf, fmt, arg)))
|
|
#else
|
|
#define LUA_PRINTF_ATTR(fmt, arg)
|
|
#endif
|
|
|
|
#ifdef _MSC_VER
|
|
#define LUA_NORETURN __declspec(noreturn)
|
|
#else
|
|
#define LUA_NORETURN __attribute__((__noreturn__))
|
|
#endif
|
|
|
|
// Can be used to reconfigure visibility/exports for public APIs
|
|
#ifndef LUA_API
|
|
#define LUA_API extern
|
|
#endif
|
|
|
|
#define LUALIB_API LUA_API
|
|
|
|
// Can be used to reconfigure visibility for internal APIs
|
|
#if defined(__GNUC__)
|
|
#define LUAI_FUNC __attribute__((visibility("hidden"))) extern
|
|
#define LUAI_DATA LUAI_FUNC
|
|
#else
|
|
#define LUAI_FUNC extern
|
|
#define LUAI_DATA extern
|
|
#endif
|
|
|
|
// Can be used to reconfigure internal error handling to use longjmp instead of C++ EH
|
|
#ifndef LUA_USE_LONGJMP
|
|
#define LUA_USE_LONGJMP 0
|
|
#endif
|
|
|
|
// LUA_IDSIZE gives the maximum size for the description of the source
|
|
#ifndef LUA_IDSIZE
|
|
#define LUA_IDSIZE 256
|
|
#endif
|
|
|
|
// LUA_MINSTACK is the guaranteed number of Lua stack slots available to a C function
|
|
#ifndef LUA_MINSTACK
|
|
#define LUA_MINSTACK 20
|
|
#endif
|
|
|
|
// LUAI_MAXCSTACK limits the number of Lua stack slots that a C function can use
|
|
#ifndef LUAI_MAXCSTACK
|
|
#define LUAI_MAXCSTACK 8000
|
|
#endif
|
|
|
|
// LUAI_MAXCALLS limits the number of nested calls
|
|
#ifndef LUAI_MAXCALLS
|
|
#define LUAI_MAXCALLS 20000
|
|
#endif
|
|
|
|
// LUAI_MAXCCALLS is the maximum depth for nested C calls; this limit depends on native stack size
|
|
#ifndef LUAI_MAXCCALLS
|
|
#define LUAI_MAXCCALLS 200
|
|
#endif
|
|
|
|
// buffer size used for on-stack string operations; this limit depends on native stack size
|
|
#ifndef LUA_BUFFERSIZE
|
|
#define LUA_BUFFERSIZE 512
|
|
#endif
|
|
|
|
// number of valid Lua userdata tags
|
|
#ifndef LUA_UTAG_LIMIT
|
|
#define LUA_UTAG_LIMIT 128
|
|
#endif
|
|
|
|
// number of valid Lua lightuserdata tags
|
|
#ifndef LUA_LUTAG_LIMIT
|
|
#define LUA_LUTAG_LIMIT 128
|
|
#endif
|
|
|
|
// upper bound for number of size classes used by page allocator
|
|
#ifndef LUA_SIZECLASSES
|
|
#define LUA_SIZECLASSES 32
|
|
#endif
|
|
|
|
// available number of separate memory categories
|
|
#ifndef LUA_MEMORY_CATEGORIES
|
|
#define LUA_MEMORY_CATEGORIES 256
|
|
#endif
|
|
|
|
// minimum size for the string table (must be power of 2)
|
|
#ifndef LUA_MINSTRTABSIZE
|
|
#define LUA_MINSTRTABSIZE 32
|
|
#endif
|
|
|
|
// maximum number of captures supported by pattern matching
|
|
#ifndef LUA_MAXCAPTURES
|
|
#define LUA_MAXCAPTURES 32
|
|
#endif
|
|
|
|
// }==================================================================
|
|
|
|
/*
|
|
@@ LUAI_USER_ALIGNMENT_T is a type that requires maximum alignment.
|
|
** CHANGE it if your system requires alignments larger than double. (For
|
|
** instance, if your system supports long doubles and they must be
|
|
** aligned in 16-byte boundaries, then you should add long double in the
|
|
** union.) Probably you do not need to change this.
|
|
*/
|
|
#define LUAI_USER_ALIGNMENT_T \
|
|
union \
|
|
{ \
|
|
double u; \
|
|
void* s; \
|
|
long l; \
|
|
}
|
|
|
|
#ifndef LUA_VECTOR_SIZE
|
|
#define LUA_VECTOR_SIZE 3 // must be 3 or 4
|
|
#endif
|
|
|
|
#define LUA_EXTRA_SIZE (LUA_VECTOR_SIZE - 2)
|