LuaJIT Change History

-This is a list of changes between the released versions of LuaJIT.
-The current development version is LuaJIT 2.0.0-beta9.
-The current stable version is LuaJIT 1.1.7. -

-Please check the -» Online Change History -to see whether newer versions are available. -

- -

LuaJIT 2.0.0-beta9 — 2011-12-14

New features: -
- PPC port of LuaJIT is complete. Default is the dual-number port -(usually faster). Single-number port selectable via src/Makefile -at build time.
- Add FFI callback support.
- Extend -b to generate .c, .h or .obj/.o -files with embedded bytecode.
- Allow loading embedded bytecode with require().
- From Lua 5.2: Change to '\z' escape. Reject undefined escape -sequences.
Correctness and completeness: -
- Fix OSX 10.7 build. Fix install_name and versioning on OSX.
- Fix iOS build.
- Install dis_arm.lua, too.
- Mark installed shared library as executable.
- Add debug option to msvcbuild.bat and improve error handling.
- Fix data-flow analysis for iterators.
- Fix forced unwinding triggered by external unwinder.
- Record missing for loop slot loads (return to lower frame).
- Always use ANSI variants of Windows system functions.
- Fix GC barrier for multi-result table constructor (TSETM).
- Fix/add various FOLD rules.
- Add potential PHI for number conversions due to type instability.
- Do not eliminate PHIs only referenced from other PHIs.
- Correctly anchor implicit number to string conversions in Lua/C API.
- Fix various stack limit checks.
- x64: Use thread-safe exceptions for external unwinding (GCC platforms).
- x64: Fix result type of cdata index conversions.
- x64: Fix math.random() and bit.bswap() code generation.
- x64: Fix lightuserdata comparisons.
- x64: Always extend stack-passed arguments to pointer size.
- ARM: Many fixes to code generation backend.
- PPC/e500: Fix dispatch for binop metamethods.
- PPC/e500: Save/restore condition registers when entering/leaving the VM.
- PPC/e500: Fix write barrier in stores of strings to upvalues.
FFI library: -
- Fix C comment parsing.
- Fix snapshot optimization for cdata comparisons.
- Fix recording of const/enum lookups in namespaces.
- Fix call argument and return handling for I8/U8/I16/U16 types.
- Fix unfused loads of float fields.
- Fix ffi.string() recording.
- Save GetLastError() around ffi.load() and symbol -resolving, too.
- Improve ld script detection in ffi.load().
- Record loads/stores to external variables in namespaces.
- Compile calls to stdcall, fastcall and vararg functions.
- Treat function ctypes like pointers in comparisons.
- Resolve __call metamethod for pointers, too.
- Record C function calls with bool return values.
- Record ffi.errno().
- x86: Fix number to uint32_t conversion rounding.
- x86: Fix 64 bit arithmetic in assembler backend.
- x64: Fix struct-by-value calling conventions.
- ARM: Ensure invocation of SPLIT pass for float conversions.
Structural and performance enhancements: -
- Display trace types with -jv and -jdump.
- Record isolated calls. But prefer recording loops over calls.
- Specialize to prototype for non-monomorphic functions. Solves the -trace-explosion problem for closure-heavy programming styles.
- Always generate a portable vmdef.lua. Easier for distros.

- -

LuaJIT 2.0.0-beta8 — 2011-06-23

New features: -
- Soft-float ARM port of LuaJIT is complete.
- Add support for bytecode loading/saving and -b command line -option.
- From Lua 5.2: __len metamethod for tables -(disabled by default).
Correctness and completeness: -
- ARM: Misc. fixes for interpreter.
- x86/x64: Fix bit.* argument checking in interpreter.
- Catch early out-of-memory in memory allocator initialization.
- Fix data-flow analysis for paths leading to an upvalue close.
- Fix check for missing arguments in string.format().
- Fix Solaris/x86 build (note: not a supported target).
- Fix recording of loops with instable directions in side traces.
- x86/x64: Fix fusion of comparisons with u8/u16 -XLOAD.
- x86/x64: Fix register allocation for variable shifts.
FFI library: -
- Add ffi.errno(). Save errno/GetLastError() -around allocations etc.
- Fix __gc for VLA/VLS cdata objects.
- Fix recording of casts from 32 bit cdata pointers to integers.
- tonumber(cdata) returns nil for non-numbers.
- Show address pointed to for tostring(pointer).
- Print NULL pointers as "cdata<... *>: NULL".
- Support __tostring metamethod for pointers to structs, too.
Structural and performance enhancements: -
- More tuning for loop unrolling heuristics.
- Flatten and compress in-memory debug info (saves ~70%).

- -

LuaJIT 2.0.0-beta7 — 2011-05-05

New features: -
- ARM port of the LuaJIT interpreter is complete.
- FFI library: Add ffi.gc(), ffi.metatype(), -ffi.istype().
- FFI library: Resolve ld script redirection in ffi.load().
- From Lua 5.2: package.searchpath(), fp:read("*L"), -load(string).
- From Lua 5.2, disabled by default: empty statement, -table.unpack(), modified coroutine.running().
Correctness and completeness: -
- FFI library: numerous fixes.
- Fix type mismatches in store-to-load forwarding.
- Fix error handling within metamethods.
- Fix table.maxn().
- Improve accuracy of x^-k on x64.
- Fix code generation for Intel Atom in x64 mode.
- Fix narrowing of POW.
- Fix recording of retried fast functions.
- Fix code generation for bit.bnot() and multiplies.
- Fix error location within cpcall frames.
- Add workaround for old libgcc unwind bug.
- Fix lua_yield() and getmetatable(lightuserdata) on x64.
- Misc. fixes for PPC/e500 interpreter.
- Fix stack slot updates for down-recursion.
Structural and performance enhancements: -
- Add dual-number mode (int/double) for the VM. Enabled for ARM.
- Improve narrowing of arithmetic operators and for loops.
- Tune loop unrolling heuristics and increase trace recorder limits.
- Eliminate dead slots in snapshots using bytecode data-flow analysis.
- Avoid phantom stores to proxy tables.
- Optimize lookups in empty proxy tables.
- Improve bytecode optimization of and/or operators.

- -

LuaJIT 2.0.0-beta6 — 2011-02-11

New features: -
- PowerPC/e500v2 port of the LuaJIT interpreter is complete.
- Various minor features from Lua 5.2: Hex escapes in literals, -'\*' escape, reversible string.format("%q",s), -"%g" pattern, table.sort checks callbacks, -os.exit(status|true|false[,close]).
- Lua 5.2 __pairs and __ipairs metamethods -(disabled by default).
- Initial release of the FFI library.
Correctness and completeness: -
- Fix string.format() for non-finite numbers.
- Fix memory leak when compiled to use the built-in allocator.
- x86/x64: Fix unnecessary resize in TSETM bytecode.
- Fix various GC issues with traces and jit.flush().
- x64: Fix fusion of indexes for array references.
- x86/x64: Fix stack overflow handling for coroutine results.
- Enable low-2GB memory allocation on FreeBSD/x64.
- Fix collectgarbage("count") result if more than 2GB is in use.
- Fix parsing of hex floats.
- x86/x64: Fix loop branch inversion with trailing -HREF+NE/EQ.
- Add jit.os string.
- coroutine.create() permits running C functions, too.
- Fix OSX build to work with newer ld64 versions.
- Fix bytecode optimization of and/or operators.
Structural and performance enhancements: -
- Emit specialized bytecode for pairs()/next().
- Improve bytecode coalescing of nil constants.
- Compile calls to vararg functions.
- Compile select().
- Improve alias analysis, esp. for loads from allocations.
- Tuning of various compiler heuristics.
- Refactor and extend IR conversion instructions.
- x86/x64: Various backend enhancements related to the FFI.
- Add SPLIT pass to split 64 bit IR instructions for 32 bit CPUs.

- -

LuaJIT 2.0.0-beta5 — 2010-08-24

Correctness and completeness: -
- Fix trace exit dispatch to function headers.
- Fix Windows and OSX builds with LUAJIT_DISABLE_JIT.
- Reorganize and fix placement of generated machine code on x64.
- Fix TNEW in x64 interpreter.
- Do not eliminate PHIs for values only referenced from side exits.
- OS-independent canonicalization of strings for non-finite numbers.
- Fix string.char() range check on x64.
- Fix tostring() resolving within print().
- Fix error handling for next().
- Fix passing of constant arguments to external calls on x64.
- Fix interpreter argument check for two-argument SSE math functions.
- Fix C frame chain corruption caused by lua_cpcall().
- Fix return from pcall() within active hook.
Structural and performance enhancements: -
- Replace on-trace GC frame syncing with interpreter exit.
- Improve hash lookup specialization by not removing dead keys during GC.
- Turn traces into true GC objects.
- Avoid starting a GC cycle immediately after library init.
- Add weak guards to improve dead-code elimination.
- Speed up string interning.

- -

LuaJIT 2.0.0-beta4 — 2010-03-28

Correctness and completeness: -
- Fix precondition for on-trace creation of table keys.
- Fix {f()} on x64 when table is resized.
- Fix folding of ordered comparisons with same references.
- Fix snapshot restores for multi-result bytecodes.
- Fix potential hang when recording bytecode with nested closures.
- Fix recording of getmetatable(), tonumber() and bad argument types.
- Fix SLOAD fusion across returns to lower frames.
Structural and performance enhancements: -
- Add array bounds check elimination. -Oabc is enabled by default.
- More tuning for x64, e.g. smaller table objects.

- -

LuaJIT 2.0.0-beta3 — 2010-03-07

LuaJIT x64 port: -
- Port integrated memory allocator to Linux/x64, Windows/x64 and OSX/x64.
- Port interpreter and JIT compiler to x64.
- Port DynASM to x64.
- Many 32/64 bit cleanups in the VM.
- Allow building the interpreter with either x87 or SSE2 arithmetics.
- Add external unwinding and C++ exception interop (default on x64).
Correctness and completeness: -
- Fix constructor bytecode generation for certain conditional values.
- Fix some cases of ordered string comparisons.
- Fix lua_tocfunction().
- Fix cutoff register in JMP bytecode for some conditional expressions.
- Fix PHI marking algorithm for references from variant slots.
- Fix package.cpath for non-default PREFIX.
- Fix DWARF2 frame unwind information for interpreter on OSX.
- Drive the GC forward on string allocations in the parser.
- Implement call/return hooks (zero-cost if disabled).
- Implement yield from C hooks.
- Disable JIT compiler on older non-SSE2 CPUs instead of aborting.
Structural and performance enhancements: -
- Compile recursive code (tail-, up- and down-recursion).
- Improve heuristics for bytecode penalties and blacklisting.
- Split CALL/FUNC recording and clean up fast function call semantics.
- Major redesign of internal function call handling.
- Improve FOR loop const specialization and integerness checks.
- Switch to pre-initialized stacks. Avoid frame-clearing.
- Colocation of prototypes and related data: bytecode, constants, debug info.
- Cleanup parser and streamline bytecode generation.
- Add support for weak IR references to register allocator.
- Switch to compressed, extensible snapshots.
- Compile returns to frames below the start frame.
- Improve alias analysis of upvalues using a disambiguation hash value.
- Compile floor/ceil/trunc to SSE2 helper calls or SSE4.1 instructions.
- Add generic C call handling to IR and backend.
- Improve KNUM fuse vs. load heuristics.
- Compile various io.*() functions.
- Compile math.sinh(), math.cosh(), math.tanh() -and math.random().

- -

LuaJIT 2.0.0-beta2 — 2009-11-09

Reorganize build system. Build static+shared library on POSIX.
Allow C++ exception conversion on all platforms -using a wrapper function.
Automatically catch C++ exceptions and rethrow Lua error -(DWARF2 only).
Check for the correct x87 FPU precision at strategic points.
Always use wrappers for libm functions.
Resurrect metamethod name strings before copying them.
Mark current trace, even if compiler is idle.
Ensure FILE metatable is created only once.
Fix type comparisons when different integer types are involved.
Fix getmetatable() recording.
Fix TDUP with dead keys in template table.
jit.flush(tr) returns status. -Prevent manual flush of a trace that's still linked.
Improve register allocation heuristics for invariant references.
Compile the push/pop variants of table.insert() and -table.remove().
Compatibility with MSVC link /debug.
Fix lua_iscfunction().
Fix math.random() when compiled with -fpic (OSX).
Fix table.maxn().
Bump MACOSX_DEPLOYMENT_TARGET to 10.4
luaL_check*() and luaL_opt*() now support -negative arguments, too.
-This matches the behavior of Lua 5.1, but not the specification.

- -

LuaJIT 2.0.0-beta1 — 2009-10-31

This is the first public release of LuaJIT 2.0.
The whole VM has been rewritten from the ground up, so there's -no point in listing differences over earlier versions.

- -

LuaJIT 1.1.7 — 2011-05-05

Added fixes for the -» currently known bugs in Lua 5.1.4.

- -

LuaJIT 1.1.6 — 2010-03-28

Added fixes for the -» currently known bugs in Lua 5.1.4.
Removed wrong GC check in jit_createstate(). -Thanks to Tim Mensch.
Fixed bad assertions while compiling table.insert() and -table.remove().

- -

LuaJIT 1.1.5 — 2008-10-25

Merged with Lua 5.1.4. Fixes all -» known bugs in Lua 5.1.3.

- -

LuaJIT 1.1.4 — 2008-02-05

Merged with Lua 5.1.3. Fixes all -» known bugs in Lua 5.1.2.
Fixed possible (but unlikely) stack corruption while compiling -k^x expressions.
Fixed DynASM template for cmpss instruction.

- -

LuaJIT 1.1.3 — 2007-05-24

Merged with Lua 5.1.2. Fixes all -» known bugs in Lua 5.1.1.
Merged pending Lua 5.1.x fixes: "return -nil" bug, spurious count hook call.
Remove a (sometimes) wrong assertion in luaJIT_findpc().
DynASM now allows labels for displacements and .aword.
Fix some compiler warnings for DynASM glue (internal API change).
Correct naming for SSSE3 (temporarily known as SSE4) in DynASM and x86 disassembler.
The loadable debug modules now handle redirection to stdout -(e.g. -j trace=-).

- -

LuaJIT 1.1.2 — 2006-06-24

Fix MSVC inline assembly: use only local variables with -lua_number2int().
Fix "attempt to call a thread value" bug on Mac OS X: -make values of consts used as lightuserdata keys unique -to avoid joining by the compiler/linker.

- -

LuaJIT 1.1.1 — 2006-06-20

Merged with Lua 5.1.1. Fixes all -» known bugs in Lua 5.1.
Enforce (dynamic) linker error for EXE/DLL version mismatches.
Minor changes to DynASM: faster pre-processing, smaller encoding -for some immediates.

-This release is in sync with Coco 1.1.1 (see the -» Coco Change History). -

- -

LuaJIT 1.1.0 — 2006-03-13

Merged with Lua 5.1 (final).
New JIT call frame setup: -
- The C stack is kept 16 byte aligned (faster). -Mandatory for Mac OS X on Intel, too.
- Faster calling conventions for internal C helper functions.
- Better instruction scheduling for function prologue, OP_CALL and -OP_RETURN.
Miscellaneous optimizations: -
- Faster loads of FP constants. Remove narrow-to-wide store-to-load -forwarding stalls.
- Use (scalar) SSE2 ops (if the CPU supports it) to speed up slot moves -and FP to integer conversions.
- Optimized the two-argument form of OP_CONCAT (a..b).
- Inlined OP_MOD (a%b). -With better accuracy than the C variant, too.
- Inlined OP_POW (a^b). Unroll x^k or -use k^x = 2^(log2(k)*x) or call pow().
Changes in the optimizer: -
- Improved hinting for table keys derived from table values -(t1[t2[x]]).
- Lookup hinting now works with arbitrary object types and -supports index chains, too.
- Generate type hints for arithmetic and comparison operators, -OP_LEN, OP_CONCAT and OP_FORPREP.
- Remove several hint definitions in favour of a generic COMBINE hint.
- Complete rewrite of jit.opt_inline module -(ex jit.opt_lib).
Use adaptive deoptimization: -
- If runtime verification of a contract fails, the affected -instruction is recompiled and patched on-the-fly. -Regular programs will trigger deoptimization only occasionally.
- This avoids generating code for uncommon fallback cases -most of the time. Generated code is up to 30% smaller compared to -LuaJIT 1.0.3.
- Deoptimization is used for many opcodes and contracts: -
  - OP_CALL, OP_TAILCALL: type mismatch for callable.
  - Inlined calls: closure mismatch, parameter number and type mismatches.
  - OP_GETTABLE, OP_SETTABLE: table or key type and range mismatches.
  - All arithmetic and comparison operators, OP_LEN, OP_CONCAT, -OP_FORPREP: operand type and range mismatches.
- Complete redesign of the debug and traceback info -(bytecode ↔ mcode) to support deoptimization. -Much more flexible and needs only 50% of the space.
- The modules jit.trace, jit.dumphints and -jit.dump handle deoptimization.
Inlined many popular library functions -(for commonly used arguments only): -
- Most math.* functions (the 18 most used ones) -[2x-10x faster].
- string.len, string.sub and string.char -[2x-10x faster].
- table.insert, table.remove and table.getn -[3x-5x faster].
- coroutine.yield and coroutine.resume -[3x-5x faster].
- pairs, ipairs and the corresponding iterators -[8x-15x faster].
Changes in the core and loadable modules and the stand-alone executable: -
- Added jit.version, jit.version_num -and jit.arch.
- Reorganized some internal API functions (jit.util.*mcode*).
- The -j dump output now shows JSUB names, too.
- New x86 disassembler module written in pure Lua. No dependency -on ndisasm anymore. Flexible API, very compact (500 lines) -and complete (x87, MMX, SSE, SSE2, SSE3, SSSE3, privileged instructions).
- luajit -v prints the LuaJIT version and copyright -on a separate line.
Added SSE, SSE2, SSE3 and SSSE3 support to DynASM.
Miscellaneous doc changes. Added a section about -embedding LuaJIT.

-This release is in sync with Coco 1.1.0 (see the -» Coco Change History). -

- -

LuaJIT 1.0.3 — 2005-09-08

Even more docs.
Unified closure checks in jit.*.
Fixed some range checks in jit.util.*.
Fixed __newindex call originating from jit_settable_str().
Merged with Lua 5.1 alpha (including early bug fixes).

-This is the first public release of LuaJIT. -

- -

LuaJIT 1.0.2 — 2005-09-02

Add support for flushing the Valgrind translation cache
-(MYCFLAGS= -DUSE_VALGRIND).
Add support for freeing executable mcode memory to the mmap()-based -variant for POSIX systems.
Reorganized the C function signature handling in -jit.opt_lib.
Changed to index-based hints for inlining C functions. -Still no support in the backend for inlining.
Hardcode HEAP_CREATE_ENABLE_EXECUTE value if undefined.
Misc. changes to the jit.* modules.
Misc. changes to the Makefiles.
Lots of new docs.
Complete doc reorg.

-Not released because Lua 5.1 alpha came out today. -

- -

LuaJIT 1.0.1 — 2005-08-31

Missing GC step in OP_CONCAT.
Fix result handling for C –> JIT calls.
Detect CPU feature bits.
Encode conditional moves (fucomip) only when supported.
Add fallback instructions for FP compares.
Add support for LUA_COMPAT_VARARG. Still disabled by default.
MSVC needs a specific place for the CALLBACK attribute -(David Burgess).
Misc. doc updates.

-Interim non-public release. -Special thanks to Adam D. Moss for reporting most of the bugs. -

- -

LuaJIT 1.0.0 — 2005-08-29

-This is the initial non-public release of LuaJIT. -

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