ChangeLog

New in 2014.08

+ Add support for JIT compilation on x64 (when configured with --enable-jit);
  supports basic arithmetic and logical operations, branching, method finding,
  invocation with argument passing, basic parameter handling, boxing/unboxing,
  attribute access, array and hash access, some big integer operations, some
  string operations, type checks, and more. Integrated with deoptimization,
  OSR (On Stack Replacement), extension ops, and exception handling.
+ Specialize various cases of istrue/isfalse to remove some indirections
+ Add charrange handling to the NFA evaluator
+ Update Unicode database generation script with latest string API
+ Add char name lookup aliases (LF, FF, CR and NEL) as line separators
+ Update moar-gdb.py for new structure of MVMString
+ Add Configure support for ASAN
+ Fix multi cache bug for no positionals, some nameds case
+ Make spesh dump show numeric literals and lexicals properly
+ Assorted OSR fixes for frames that deoptimized, then hit OSR points
+ Fix a number of SSA/dominance memory leaks
+ Fix memory leak in inlining
+ Make dead code elimination not cause unrequired guards to be kept
+ Add an API for extops to be involved in fact discovery and specialization
+ Add type and no-container facts for bigint ops
+ Support inlining of frames with handlers
+ Enable inlining of lexotic (return) handlers
+ Allow addition of temporary registers when specializing
+ Specialize boxing and unboxing of args, both named and positional
+ Avoid repeatedly allocating memory for NFAs
+ Cache frame index in MAST assembly, to avoid a linear scan
+ Fix various dynamic variable and inlining interaction bugs
+ Add a dynamic variable lookup cache
+ Devirtualize serialization read/write functions
+ Make full frame deserialization lazy, reducing memory and startup time
+ Handle static lexical values far more efficiently
+ Identify MAST nodes in assembler by exact type, cheapening assembly
+ Specialize smart stringify/numify into simpler ops in some cases
+ MAST::Label works on identify now, not name matching
+ Make "allocate in gen2" mode reentrant
+ Support lazy deserialization of static lexical values, method caches, and
  meta-objects
+ Remove some unused fields from STable
+ Optimize some simple control exceptions into gotos
+ Don't redo dead instruction elim on inlinees
+ Make sure inlined args are always marked as used, fixing a bug
+ Add an int -> str cache for 0..^64
+ Add asynchronous process spawning, I/O, and killing
+ Check dll cache before searching through libpath, saving many stats
+ Make a better guess at MAST assembly output buffer sizes
+ Add a mechanism for debugging strand issues
+ Fix bug in string repeat of an already repeated strand
+ Complain properly about missing late-bound methods
+ Clear special return data more eagerly, fixing a double-free
+ Refactor get_storage_spec
+ Fix P6bigint unbox portability bug

New in 2014.07

+ Make default file mode 0666
+ Auto-detect computed goto support and enable it when available
+ Implement On Stack Replacement for hot loops
+ Fix and enable isconcrete optimization
+ Use const_i64_16 in spesh-produced code for more compact output
+ Fix bug where [work|env]_alloc were not cleared, leading to mis-frees
+ Support inlining frames that use with extops
+ Add missing decl in header to quiet warnings
+ Fix logical bug in fixed-size-allocator
+ Fix capturelex race condition
+ Add missing MVMROOT in ConditionVariable setup
+ Don't share cached Lexotics over threads
+ Re-order code to avoid race on event loop startup
+ Add a bunch of missing MVMROOTing in asyncsocket
+ Make exit get out quickly
+ Close async sockets on event loop thread to avoid corruption
+ Make --no-optimize and --no-debug work in Configure
+ Implement (de)serializing of Array[uint]
+ Specialize getlexperinvtype_o (enables better roles optimization)
+ Allow pointer math using CPointer repr
+ Fix typo in CArray.elems error message
+ Add a cast to get rid of a warning in nativecall.c
+ Fix merging of inline table entries
+ Eliminate unused guard instructions at end of specialization
+ Update uthash to latest version
+ Correct computation of lexical vivifications
+ Add nativecallcast operation
+ Fix use-after-free bug with thread entry callsite
+ Cope with cross-deopt-point usage analysis
+ Give ContainerSpec a spesh function, use it for decont
+ Make various spesh things available publicly, for VM extensions
+ Significantly overhaul the strings code, fixing many performance issues
+ Optimize find_cclass and find_not_cclass

New in 2014.06

+ Correct closure semantics of native callbacks
+ Add ops for 2-possibility named parameter handling.
+ Start storing named argument names in callsite objects
+ Start interning callsites with named arguments
+ Specializer can turn named arg resolution to indexed lookups
+ Specializer can optimize named args
+ Specializer adds facts and guards for named args
+ Implement cancelling listening on a socket
+ Implement async bytes reads from sockets
+ Optimize invocation by pre-selecting callee spesh cand if possible
+ Pick a spesh threshold by bytecode size rather than a constant
+ Mark ops that are not suitable for inlining
+ Add an operand type for spesh slots
+ Implement basic inlining
+ Implement deoptimization of inlined calls, which uninlines
+ Make interp trace output more useful; include op
+ Have invoke/return end a basic block
+ Add a thread-safe fixed-size allocator
+ Use fixed-size allocator for frames/work/env.
+ Use fixed-size allocator for hash entries
+ Use fixed-size allocator for named used flags.
+ Don't refuse to spesh if we've a slurpy positional
+ Can do coerce_in of literals at spesh-time
+ Fix spesh frame handler end annotation motion in instruction deletion
+ Fix spesh fact marking bug

New in 2014.05

+ Add a libuv-managed event loop thread
+ Implement timers
+ Implement nqp::signal; support various signals
+ Add async read/write sections to IO op table
+ Implement async socket listen/connect
+ Implement async read/write ops
+ Implement chars case of async socket reads
+ Fix HLL mapping of type objects
+ Implement file watchers
+ Add infrastructure for cancellation
+ Implement cancellation of timers
+ stat the target of a symlink when we query for filesize
+ Dump deopt instruction spesh annotations
+ stat file descriptor in eof() when filename is unset
+ Serialize CStruct repr_data
+ Add MVMNull REPR and a singleton VMNull instance
+ Teach various parts of the VM about VMNull
+ Lazily allocate lexical containers
+ Optimize frame allocation
+ Remove BOM-discarding code from MVM_string_utf8_decode()
+ MVM_string_utf8_decode() should take a MVMuint8 *, not a char *
+ P6opaque now handles C structure member alignment, just like CStruct does
+ Steal P5's unlink magic for Windows; clear readonly flag when needed
+ Add lexical lookup lifetime hinting ops
+ Re-organize spesh to have log/specialize phases
+ Use spesh logging to emit guards into code
+ getlexstatic_o optimization in spesh
+ Better error on handler fixup failure in spesh
+ Implement op execname, which stores the path of the runner
+ Implement all vs. one deopt
+ Fix moving of handler annotations
+ Basic dumping of facts in spesh
+ Cope with annotations being moved to a phi
+ Make sure we don't clobber block handler setting in spesh
+ Iterate to fixed point when finding unused instructions, giving better results
+ Pre-invalidate all deopt target addresses, to catch fixup failures
+ Optimize simple calls and multi-dispatch at spesh time if possible
+ Add Makefile rules to generate pre-processed source
+ Add Makefile rules to generate assembler
+ Support for ARMv6. Don't try to read unaligned doubles or long longs
+ Ensure that MVMCompUnit can correctly free data_start
+ MVMStaticFrame now supports bytecode pointing to a private malloc()ed copy.
+ Do proper endian correction on bytecode
+ Add Ops for 32/16 bit 64 int literals
+ isnonnull op for use in spesh
+ turn islist/... into either isnonnull or a literal 0.
+ Teach spesh_diff.p6 about the new output of spesh dump
+ Teach spesh_diff.p6 about Facts
+ improve run time performance of spesh_diff.p6
+ Avoid using an uninitialized variable.
+ Harvest strings in facts discovery process
+ Specialise can and can_s ops into const_i64 when possible
+ Change the way we store SCs in object headers to allow faster lookups of indexes
+ Fix bigint bitops
+ Ensure spesh_alloc aligns on platforms needing it
+ Include SC identifiers in bytecode dump
+ Make dump_backtrace more widely available.
+ Merge the bodies of MVM_sc_get_{obj,stable}_sc and *_set_*
+ Change serialization context indexes to be unsigned. Use ~0 as a sentinel.
+ Add inline functions to wrap accesses to sc.sc_idx and sc.idx
+ Add struct MVMSerializationIndex to hold large STable indexes
+ Free any allocated MVMSerializationIndex structs
+ Add a probe to determine the pointer size
+ Conditionally compile the MVMSerializationIndex for 32 bit platforms only
+ Allocate a MVMSerializationIndex if sc_idx would overflow in the union
+ Specialize getattr_[ins] on P6opaque
+ Fix bigint upgrade check
+ Optimize object attribute accesses in spesh
+ Spesh indirect form of attr ops with known names
+ Rakudo Bug #121273 fixed - losing a 0 from end of exponent
+ Re-arrange various structures for memory saving
+ Add handler infrastructure for supporting labeled loop exceptions

New in 2014.04

+ Brought thread ops in line with nqp:: op API
+ No longer inherit caller chain when starting a new thread
+ Fix a range of parallel garbage collection bugs
+ Block/unblock threads for GC while sleeping
+ Implement reentrant mutexes
+ Implemented semaphores
+ Implemented concurrent blocking queue support
+ Implement condition variables
+ Main thread has ID 1 now
+ Move nursery corruption check to after inter-thread work passing
+ Fix a gen2roots compaction optimization bug
+ Add flag '--has-sha' option to Configure to use a system SHA-1 library
+ GC orchestration cleanups and extra logging
+ Compact the gen2 overflows list
+ Fix decodestream_bytes_to_buf eating too much data
+ Added some missing MVMROOTs on config setup
+ Removed duplicate gen2 root cleanup call
+ Small cleanups to serialization
+ Avoid an extra level of function call in various REPR allocate functions
+ Add locking for IO handles
+ Add the Configure flags '--has-libuv and '--has-libatomic_ops'
+ Shortcut shr when we have a small lhs but rhs is >= 32
+ Add logic to turn bytecode into SSA form, and from SSA back to bytecode
+ Added infrastructure for "spesh ops", to use in type-specialized bytecode
+ Start interning positional callsites
+ Keep a rough call count per static frame
+ Add bytecdoe specialization infrastructure
+ Optimize simple positional arg fetch in specialized bytecode
+ Resolve methods at specialization time when type is known
+ Add a monomorphic method cache
+ If MVM_SPESH_LOG is in env, log spesh work to it
+ Turn known-unrequired decont into set
+ Make MVM_SPESH_DISABLE env var disable spesh
+ Add :pure annotations to side-effect-free ops; eliminate dead code
+ Add a tool for splitting and diffing spesh log output
+ Add setmultispec mechanism for optimizing away only-star proto
+ Optimize optional positoin arguments in bytecode specialization
+ Optimize out istype for a spesh-time-known value or type
+ Optimize if_i and unless_i for known values
+ Corrected atan2 op signature.
+ Implement de-optimization on mixins
+ Don't lose HLL owner during serialization
+ Optimize away hllize when possible
+ Optimize away assertparamcheck when possible
+ Infrastructure to allow REPRs to participate in spesh
+ Optimize object creation in common cases with known types
+ Small fixes to MVM_string_(latin1|windows1252)_encode_substr
+ Optimize bindattr_o on P6opaque when possible.
+ Change the way lexotic is handled to avoid the need for allocation
+ Specialize empty named slurpy args.
+ Add a way to flag a frame as a "thunk".
+ Add ctx[outer|caller]skipthunks ops.
+ Make backtrace generation ignore thunks.
+ When readline/linenoise see EOF, mark handle EOF
+ Set hint for invokespec and multispec, improving invocation performance
+ Improve the VM exit strategy, so non-app-lifetime threads are waited on
+ Correctly handle temp roots stack in callbacks
+ add sched_yield for NetBSD
+ Fix callsite size calculation in tweak_cs
+ Fix buffer overflow in UTF-16 encoding
+ Trigger repossession on OP(push_*)
+ Fake up a final entry off the end of Unicode, fixing some lookup bugs

New in 2014.03

+ Implement a fast-path for string strand flattening
+ Fix character lookup by name sometimes giving wrong result
+ Control and printable now know about Latin-1 control characters
+ Fix bug in Latin-1 handling
+ Fix and optimize various character property lookups
+ Implement lookup of non-boolean Unicode properties
+ Implement character code to name lookup
+ Implement lookup of enum/stringy Unicode properties
+ Fix memory leak of active handlers in continuations
+ Clear up gen2 memory at exit
+ Clear up frame pool at exit
+ Don't leak static frame instruction offsets
+ Fix memory leak in MVMHash
+ Simplified/optimized frame reference count handling in continuations
+ Fixed missing exception resume reference count decrement
+ Correct "on stack" continuation reference count handling
+ Add missing cleanup in MAST assembler
+ Fixed used named args tracking memory leak
+ Fixed SEGV in eof of non-file-based filehandle
+ Pass STDIN to subprocess in shell()
+ Fixed resolution of IPv6 host names
+ Implemented native calling
+ Implemented CPointer representation
+ Implemented CArray representation
+ Implemented CStruct representation
+ Improve GDB plug-in string usage analysis
+ Make GDB plug-in aware of gen2 overflows
+ Clean-up and optimization of many REPR allocate functions
+ Fixed over-eager / to \ conversion in nqp::shell on Windows
+ Implemented native callbacks
+ Correct copy size of args buffer, avoiding reading unmapped memory
+ Updated to new liblinenoise and re-instated usage of it
+ Bump dyncall to latest version
+ Add --has-libtommath option to Configure for using system libtommath

New in 2014.02

+ Increased precision of num => str coercion
+ Mechanism for per-HLL handling of method resolution errors
+ Gave can the same null-check semantics as findmethod
+ Fixed various "not found" lexical lookup semantics
+ Use a more efficient encoding for integers in the serialization blob
+ Implemented reposession conflict resolution handling for objects
+ Optimized GC worklist processing to avoid unrequired barriers
+ Added a GDB plugin to help analyse VM data structures, heap use, etc.
+ Zeroed memory in a few places, to avoid reading junk and quiet Valgrind
+ Simplified and fixed UTF-16 encoding
+ Implemented unsigned native integer array support
+ Added various missing write barriers on STables
+ Added openpipe functionality, to support qx/qqx in Perl 6
+ Corrected accidental and potentially explosive use of REPR(...) on STables
+ Switched to using flag bits to mark liveness in GC
+ GC forwarder pointer used in nursery now overwrites existing object body,
  saving 4 or 8 bytes on every collectable object
+ Added various GC sanity checking asserts to aid debugging
+ Encapsulated all serialization context accesses
+ Defined NDEBUG in optimized builds
+ P6bigint no longer uses libtommath for integers fitting within 32 bits
+ Optimized serialization of P6bigints fitting within 32 bits
+ Implemented link and symlink
+ Fixed mod_n op's behavior on negatives
+ Implemented floating point fallback case of the pow_I op
+ Fixed srand op to also control rand_I
+ Initialize the random seed at startup
+ Properly clean up active handlers that we unwind over
+ Radix parsing now returns an array of integers, not floating point
+ Huge refactor of I/O, fixing many bugs and leading to cleaner code
+ Proper handling of characters split over byte buffer boundaries in I/O
+ Corrected Latin-1 to be Latin-1, and added Windows-1252 encoding
+ Added a constant cache for boxing integers 0 through 15
+ Properly implemented synchronous client and server TCP socket support
+ Better estimate and perhaps shrink string memory for UTF-8 decode
+ Added probing to Configure to learn how the compiler does 'static inline'
+ Switched many macros over to static inline functions