Go 1.0 (pre-release history 2008–2012)

Everything up to the go1 tag, 2008–2012. 6g/8g/5g with the C frontend gc, Plan 9-derived C compilers and assemblers. Segmented stacks. A tcmalloc-style allocator with a stop-the-world mark-sweep collector. A global-lock M:N scheduler. hashmap.c and the 2009 and 2011 reflect redesigns. Escape analysis and a first inliner. ELF/Mach-O/PE linkers with DWARF and dead-code elimination. runtime/pprof.

Each area lists the stage every thread reached in this release (with what was left open afterwards), then changes that are not part of a thread. Thread names link to the full thread on its topic page.

Memory management

From Memory management: GC and allocator (Go 1.0–1.17)

Everything up to the go1 tag: tcmalloc-style allocator (2008-12), stop-the-world mark-sweep (2009-01), finalizers, a faster collector in 2011 (1e063b32cd), helper threads, memory release to the OS (5c598d3c9f); threads "Stop-the-world mark-sweep…", "Size classes…", "Scavenger", "Finalizers".

• Stop-the-world mark-sweep, then the parallel collector — Done:
  • 2008-2009: allocator and first collector (e29ce175ed, 1ce17918e3, 9f726c2c8b); heap map split from malloc for 64-bit (80f4ab47ee); a bug in the size-class waste check that produced far too many classes fixed (c1e748bd2e); stacks no longer malloc’d during GC (8c357ce269).
  • 2010: finalizers merged into package runtime (33e396a4a7); sweep and GC specialisation (f25586a306, fb94be55dc, 22a7f2a14d drops MHeapMapCache); GC clocked on bytes allocated (8ddd6c4181); memory profiling hook (596c16e045).
  • 2011: simpler dense heap map in bss (4608feb18b); faster allocator and collector (1e063b32cd); standard-sized stacks off the central FixAlloc (c9152a8568); helper threads for parallel marking (a5f064a3e1, 8219cc9af8); per-M MemStats caches (66d5c9b1e9, 27753ff108).
  • 2012: ReadMemStats replaces UpdateMemStats (842c906e2e); 32-bit fallback when the 64-bit reservation fails (d37a8b73c5). Left open: GC was stop-the-world and single-threaded in the go1 tag; stack and heap scanning were conservative.
• Span lifecycle in mheap: free lists, treaps, first-fit and the page reclaimer — Done: span list-based heap with coalescing (9f726c2c8b allspans), release unused memory (5c598d3c9f, see scavenger). Left open: nothing noted.
• Scavenger: returning memory to the OS — Done: user-visible periodic release of unused memory with madvise (5c598d3c9f), HeapIdle tracking (33d00fae30). Left open: fixed 2/5-minute thresholds.
• Heap address space: contiguous arena to sparse arenas — Done: dense heap map (4608feb18b), >512 MB 32-bit (70b0de8e98), alignment checks (48535ae3f1), 64→32-bit fallback (d37a8b73c5, 073aeff785, 3dcedb620c). Left open: fixed contiguous reservation.
• Finalizers and span specials — Done: finalizers, table, single goroutine (33e396a4a7, f25586a306, acfd7b8d12, 4e28cfe970, 24c58174b2, 69a91663d2). Left open: a second mark+sweep pass for finalizers existed until 4e28cfe970.
• Memory statistics and accounting — Done: per-M caches (66d5c9b1e9), HeapIdle (33d00fae30), ReadMemStats (842c906e2e), mallocs and sampling fixes (ad35cea762, 1135fc3978). Left open: nothing noted.

Other changes

• Allocator hygiene internal — free(nil) handled (0c32430534), strings allocated NUL-terminated for low-level getenv plus a 32-bit GC fix (1a0a6f9d50), malloc fixes and counters (7e5055ceea), untouched pages not touched, cutting hello-world working set from 6 MB to 1.2 MB (0d3301a557), GC and malloc performance (f25586a306, 991a968f44); early GC bug fixes (3e02987508, 7cd24361bd, b21425ddee), mcache allocation serialised (7389ab8d21), allocator fixes for 386 and GOMAXPROCS>1 (1cc8c87dc1, 250977690b), extra memory stats (d99a3da7b2).
• Out-of-memory handling internal — more graceful OOM crash (e2f9c73391), MemProfileRate=0 crash fix (1135fc3978), grsec fix (8eee153bc8), 64-bit/32-bit allocator fallback (d37a8b73c5), deadlock detection fixes during GC (5695915833, 84bb2547fb, 8584445289, 8219cc9af8).
• Residual small commits internal — early malloc bug fixes, C/gcc portability, build breaks on Windows/Plan 9/NaCl/Dragonfly, naming, position-independent code and comment/format cleanups with no separate design content: da0a7d7b8f, 7843a14df1, 9b8da82d72, 2b57a1124e, 78a6d68c86, 73c10dd967, d3a412a5ab, 74a9fc18f6, 711088106e, bada653f4d, 214a55b06a, 5c30325983, 1253c75cf5, ce020ffacd, 03f2289f7e, dc159fabff, 54193689cc^1.1, f76f120324^1.1, 6273c7324f^1.1, f24323c93e^1.1, 7847f328cd^1.1, c13866db7f^1.1, 44cf814d50^1.1, add3349867^1.1, c90850277b^1.1, c15ca825ad^1.2, 83d4cd758c^1.2, cdfbe00d91^1.2, 2ffaefd161^1.2, b9ddb0d8b3^1.2, dd50dac56c^1.2, 67c79da857^1.2, 3b089179c4^1.2, b7b93a7154^1.3, 0ef0d6cd7b^1.3, fb5e1e1fa1^1.3, 9ab4d1d6b3^1.3, 8de04c78b7^1.3, bee3848f4e^1.3, 81bc9b3ffd^1.3, 55e0f36fb4^1.3, a5b1530557^1.3, cc81712190^1.4, 92c54e4a73^1.4, 1b47af2199^1.4, 1d88f9dd4d^1.4, d889f5f01e^1.4, 99e8f40488^1.4, 5c795632d6^1.4, 37b8597178^1.5, 0e6a6c510f^1.5, d1cae6358c^1.5, ada8cdb9f6^1.5, 64e53337af^1.5.
• Remove malx and skip_depth internal — Deleted the malx function and the skip_depth argument to malloc. (6363542695)

Scheduler and concurrency

From Scheduler and concurrency runtime (Go 1.0–1.17)

The pre-release runtime: global-lock M:N scheduler, chans/select, Notes and unified OS mutexes, first sync and sync/atomic packages, timers for package time, deadlock detection and the earliest GOMAXPROCS semantics; threads: early scheduler, channels, semaphores/locks, sync, atomics.

• The G-M-P scheduler: from global-lock M:N to per-P run queues, spinning Ms and work stealing — Done: the pre-1.1 scheduler.
  • 2008: the first FIFO scheduler e7d549fbd7; first multithreading on Linux d28acc42ec; Mac kernel semaphores used only on real contention 5ff12f871f and the per-G Note removed a61bb95497; GOMAXPROCS redefined efc86a74e4, runtime.GOMAXPROCS added 7955490de2; LockOSThread/UnlockOSThread for the debugger 218c393029; sys.cas for mutexes 84ded32817.
  • 2009: G structs recycled 2aea4a063b; list of all Ms kept so the collector does not free them 93689d863c; preemption-by-GC checks in expensive routines 5328df6534 (fixed in 711088106e); runtime.Goroutines 51a2183851; idle goroutine 582fd17e11; contention reduced by waking on scheduler unlock 5e963a826c; scheduling race fixes 774333685e, 88ce9ce40c, 50d6c81d4a; no new threads during malloc 4dfd7fdde5.
  • 2010–2011: GOMAXPROCS vs GC bug 29d78f1243, running-goroutine count bd77619142; faster syscalls 025abd530e, ba134539c5; scheduling race 9bc58accce; unnecessary locking removed 6500065543; bootstrap M counted in mcpu 2572ca2ff2; main goroutine locked to main thread during init 6808da0163 and dc159fabff; runtime.NumCPU 6dfdd4c1e3; deadlock detection restored in the simplest case 84bb2547fb/5eb007dede; goroutine profile and stack dumps e4b02bfdc0. Left open: one global scheduler lock and one run queue; GC stats and goroutine ids still global (the false-sharing fixes 909f31872a, 013ad89c9b are band-aids); no preemption of running goroutines.
• Timers: timerproc goroutine → per-bucket heaps → timers on Ps — Done: runtime-provided timers for package time 3b860269ee, timer callbacks crash dc6726b37f, timer removal corruption (#2495) a899a467f2. Left open: one global heap and goroutine.
• Channels and select — Done: chan/select/close (above); select fairness 4f269d3060 and memory leak pass 3 ec53627ed5; channel data cleared on receive for GC dec248c665; make(chan [0]byte) 95323c59ea; sync channels faster 90f3cb13fb; x, ok = <-c zero value d16bc7a9f2; disallow close on receive-only channels f58ed4e641; heap sort replaces bubble sort in select (1.1) cb32ea9c19^1.1; lockorder before pollorder 53e139c7a0.
• Semaphores, runtime locks and Notes — Done: mach semaphores only under contention 5ff12f871f; sync semaphores 5bbd4c2f1b; runtime mutex across OSes ee24bfc058; lock-free stack a5dc7793c0^1.1 (Go 1.1 list). Left open: none noted.
• sync.Mutex, RWMutex, WaitGroup, Cond, Once — Done: Mutex, RWMutex rewrite 12206f64dd, Once 895c5db6df, Cond 05b1dbd0a6, Unlock-of-unlocked check 26880d7e03, atomics-based Once and RWMutex fast paths d2ab2b9f42, daaf29cf93, ee6e1a3ff7, Cond.Signal wakes previously sleeping goroutines 17bfa32fde, barrier proposal 63457d089e, armv5 support 86b0ea6447; Once.Do uses atomic Store (1.1) 8c4c6c413f^1.1.
• sync.Map, atomic.Value and sync/atomic — Done: package introduced (above) 22eab1f5c7, ARM cas fixes 540feaae47, 0b200b4d09; atomics on 386 with XADD ab596cae9e.
• Goroutine and M lifecycle: caches, ids, LockOSThread, Goexit, cgo extra Ms, deadlock detection — Done: G recycling 2aea4a063b, deadlock detection 84bb2547fb, 5eb007dede, LockOSThread 218c393029, main thread locking 6808da0163, GC stats per-M d839a809b2^1.1 (1.1 list).
• Stop-the-world, safe points and GC–scheduler interaction — Done: GOMAXPROCS vs GC fix 29d78f1243; GC in stoptheworld with parallel GC f18e4e44a3, 85916146ea.
• Scheduler diagnostics: schedtrace, GODEBUG, execution tracer, block/mutex profiles — Done: creation pc in traceback 324cc3d040; simplified stack traces 03e9ea5b74; per-pause GC stats bcd910cfe2; profiling thread creation 5b93fc9da6.
• Fast random numbers for the scheduler — Done: cputicks seeding 8e765da941, no false sharing 909f31872a.
• GOMAXPROCS, thread and resource limits — Done: GOMAXPROCS semantics efc86a74e4, 7955490de2, eb48bfbbda; NumCPU 6dfdd4c1e3.

Other changes

• Reflection and cgo support for channels user-visible — 5ddaf9a098 (reflect chans), 653cef1ba0, de7920e6fd (ChanValue Close/Len/Cap), 2e20386fc7 (cgo export library support), 95fa16a892 (C.GoStringN), db9229def8 (GoBytes), 9042c2ce68 (runtime/cgo), 2d39303429.
• Stack/morestack interplay with scheduling internal — stackalloc on the scheduler stack b5dfac45ba, 79e1db2da1, no select stack split 6a3b29895f, 5273868f67, aa3222d88f, ccdbb8a6c2, e2bde5cf9b, afc6928ad9, b701cf3332, c2b91d4889.
• Runtime cleanup and traceback internal — 88a3371a91, d6f25597bb, 1a2421e406, 3835e01d97, f6d67c9e95, d110ae8dd0, b287d7cbe1, d1cd829405.
• Memory allocator/map interplay with goroutines internal — c9152a8568 (plain malloc for stack allocation), 86e7323bdf (no static in oldstack), d6ed1b70ad (distributed ncgocall), 72e83483a7 (cgo calls 669 → 330ns), 54e9406ffb, 3b860269ee, 100a034120, a2677cf363 (GC bitmap corruption when GOMAXPROCS changes), e1b47159ab, 1707a9977f, 2e4a035995, 4d903504b3, d6c59ad7b8.
• Mutex and Notes internal — bf3dd3f0ef, ee24bfc058, b83549a7e6, be629138ab, 62d627f0bc (finalize chan semaphores), d770aadee5 (chan creation 1132 → 381ns).
• Misc bugfixes in 2008–2011 internal — 5624e34494, df8ac28975, dee07c884e, 7b454bb1d9, 2da9783e2b, 24838a2df6, 3338c71fc6, 1da727a31f, 8a9752dcfb, 79fbbe37a7, 9b827cf9a0, a6af484328, e8766354a4, 600ee088b6, 75647d2024, 60db3d6d3f, 3f19d8ae8d, cec007d3d2, d4baf3ccb7, 88ce9ce40c, d16bc7a9f2, ed575dc2b9, b33f5d537f, 9b15ad8c22.
• Early chan/select/map/interface fixes and runtime plumbing (2008–2011) internal — af58f17af9, 90da10d7ac, 949ab5c7ff, b89d630977, 504da53c85, 47e6042f73, 102b5b34a7 (drop the complicated select PRNG), 3a07d516b4, 175849295c (select pseudo-randomness), 45301ba8c0, 7c616b3809, a73817716a (one malloc per chan), 9c3ecb3617, b57afc2f83, 3935610e35, eee50ae1ac, 1f8a40d85c, 9b6d385cb5, a7f6d4066e, 408f0b1f74, e956429166, 5adbacb8e7, 90846cd447, e42d6a5fe2, 85785fe577, 1e774d9e6a, 1bef250f33.
• GC/goroutine-state interplay and misc scheduler bugs internal — 36835c7a47 (save stack trace when entering Gsyscall), 19c18358ca, 72157c300b, 214a55b06a, 052a66babd, 41554e2528, e79bcf8bfd, 74a9fc18f6, 34d413f562, 111005d32b, 150a64572b, 29aa3ffbf6, d08f0067b5, fe8ff955e9, ad9c6f7700 (debugger hooks for newprocreadylocked), a68592a4dd, 659780b643, 3f8aa662e9.
• Platform/glue internal — 72154b042f, f7f6329e26, 5bb0c4f88b, 61e0fcce8a, 73c10dd967, 62355959c6, 23c41a1ef2, 9cc8e9ef48, cd319092e0, c83451971e, a7528f1b81, 6b3357129a, 623e7de187, 69cb8fef43, d44c4c351d, 9c774c3f26, 33e9d24ad9, 3f2d787c2b, 0acd879c26, 0ae9d812c8, 03f2289f7e, 89b075cc90, 8a4c2b3cc4; docs 39ffd546bd, a03c519a8c, 76eb911a3c (Cond.Wait cannot return spuriously).
• Scheduler reorg internal — Renamed select to nextgoroutine and separated entering the scheduler (sys.gosched) from the scheduler itself. (4feda71b7d)
• Casify and clean up sys internal — Renamed and cleaned up runtime sys functions. (360962420c)
• Comments in proc.c internal — Added comments for various functions in proc.c. (4ac425fcdd)

Data structures and type metadata

From Runtime data structures and type metadata (Go 1.0–1.17)

Four years of foundations: hashmap.c, the C iface code, the 2009 reflect rewrite from string parsing to compiler-laid-out type structs, the 2011 Type/Value redesign and opaque Value, per-map hash seeds and randomized iteration.

• Hash map core: from the first hashmap.c to the 8-entry bucket design — Done:
  • 2008–2009: hashmap.c (bc0b4f0d2a), pointer keys (5adbacb8e7), hash alignment fix for data >= 8 bytes (9ed2960de8), for loops in hashmap (1f1ae404f8).
  • 2010–2011: zero value on missing key (e781303e27), large values (b198c8612e, 8599a83727), free old pieces during resize (21518ea2af), memory-leak fix (e7e5c5adb3), nil-map panics and nil range (f2852ba618, 86145611b0), gofix -r mapdelete for the delete builtin change (313c8224d5), randomized iteration start (e40d6e066a, user-visible iteration order is no longer predictable).
  • 2011-12 to 2012-03: algorithm in type data became a table pointer so compiler-generated code can be called, and the top-level map structure was trimmed from 104/80 to 24/12 bytes on 64/32-bit (b9ccd077dc); per-map hash seeds from fastrand1 (85aeeadaec). Left open: seed was not yet cryptographically random (“Fastrand1 still needs to be updated”).
• Map growth, iteration order, overflow buckets and GC interaction — Done: randomized iteration start (e40d6e066a) and incremental-growth predecessor “free old pieces” (21518ea2af). Left open: iteration over one bucket still deterministic.
• Hash functions and algorithm tables: memhash, AES hash, fallback hash — Done: alg table pointer (b9ccd077dc), float64 hash fixes (022aac7883, facee93a86), per-map seeds (85aeeadaec); 2009 alignment fix for data >= 8 (9ed2960de8).
• Compiler-generated equality and hash functions — Done: alg table (b9ccd077dc).
• Runtime type descriptors: layout, shrinking and name encoding — Done:
  • 2008: reflection from type strings; sys.Reflect/Unreflect (d6a7cefd1e, a45f947c34, 842e1a9aa7).
  • 2009: struct-based reflect data laid out by the compiler (4793400bd1, a7b4e9f03e, 58c4142e74), maps and channels reflected (764b6ec1aa, 5ddaf9a098), methods (12ebbe7463).
  • 2010–2011: Kind replaces per-type structs (45bdf0367e), gc emits correct reflect types (96db724cfc), ptrto word (8d36a78440), uintptr treated as pointer-bearing (b0c674b65d), runtime Type deleted (121a16fa95, 6a75ece01c), type-specific algorithms (b9ccd077dc). Left open: type data still lacked GC info.
• Interface values, itabs and type assertions — Done: 2008–2009: iface runtime (6f07ec721a, e2e8aa0ee1, 900e076d21, 4b8c13dc20); 2010–2012: type switch eliminates package-global-name assumption (1912632019), runtime·Type deleted.
• reflect redesign: from string parsing to Type/Value structs — Done:
  • 2008: string-parsing reflect, Value.Interface, tags (554d0aa589, 12a3435869, a45f947c34), type cache (842e1a9aa7), DeepEqual in 2009 (c4ad4f9fcf).
  • 2009: struct-based rewrite (4793400bd1, a7b4e9f03e, 58c4142e74), map/chan/method reflection (764b6ec1aa, 5ddaf9a098, 12ebbe7463), FieldByName through embedding (a288095813), DeepEqual for maps (1880b90aff).
  • 2010: Kind (45bdf0367e), Type.Bits (fc090a3a54), Append/AppendSlice (8b64cd9c5e), FieldByNameFunc (57e764171c).
  • 2011: PtrTo/Addr (e46acb091f), new Type/Value (fb175cf77e, 7b6ee1a5d4, 40fccbce6b, e1ee3b5db6), struct tag convention (25733a94fd), MethodByName (22484e2262), opaque Value (a479a45548), Interface on unexported values disallowed (304cf4dc9b), empty slice/map not DeepEqual to nil (4e65478cbd).
  • 2012: DeepEqual on funcs (3a1c226a38), Value.Interface returns immutable data (a72b87efa9), MakeSlice argument checks (11cc5a26d5).
• Slices and append: growslice, makeslice and string/slice conversions — Done: 2009–2011: copy single-byte case (20c1ec263a), typed makeslice (864c757a1c), make([]T,0) allocation-free (94c2536e3f), SliceHeader made public and fixed to use int (22ea3f9e49), gc-friendly SliceHeader (4e7aac5413).
• Strings: concatenation, conversion and printing helpers — Done: NUL-terminated allocation (1a0a6f9d50), float print format (ac5a887d5d), range UTF-8 fix (a18208fb60), maxstring race (f9f21aa1fb).

Other changes

• Early reflect (string-parsing library, 2008–2009) internal — type-string parsing support and fixes: moved into place (5d30161ca7, 8327b54169), bool, ..., NUL and tag trimming in type strings (613a5c8bc6, 16fd356679, 730fd707cb, 1ff61cefaa, 5a1cbe8b64, 546f269c3b, bdbb958895, ca9765d83a, 178e37e766), unsafe.Pointer-based objects (50d0695ccf, f5cfadde47), nil-interface and uintptr handling (ac09eb4f49, 9ba97ca308), pointer mutation support (b1d37b74d9, 419e1e05a1, 7295b61cdb, a48b35e961), array methods (e4f4ab0b8d), alignment (44a82746a1, 4e84174816, c0b8b969ae), cleanup and renames (c4af3e7c2a, ed2ac9b8b0, ba882f9940, 9526f3b841, d0424faf17, dfad8ea647, 3bc6fd63fe).
• Reflect value/type API additions user-visible — InterfaceValue.Get/Value() (ac6ebfdea9, 96cfd154d8, f96662324e), StringHeader/SliceHeader (d7a5ccf36e, 29e6eb21ec), Type.Name/PkgPath split (ba0cf083a2, 1dbd3c8d3d), FieldByName details (a93c5c8550, 123ff2ebb8, c36fbdf713), Slice of arrays and Copy of arrays (3bac16a6bf, 6850dba0ca), unexported-key MapIndex (86e6a44112), Len on strings (db0e358022), NumMethod (125e8277d5), panics on invalid Interface (a2bb0159d6), Bytes/SetBytes (00d64c7239), slice cap fix (3dc278d3e2), panic strings (cc8e12bb52), %p support via Get (148ee9c009), GC bug in Call (da225c231f), faster Get/SetValue by removing casts, 25%+ (81cb189a06), kind values and KindUnsafePointer (bbaef5f4dc, 454f03ff0b), documentation (be560e0401, 795ff00df0, ab44a814c2, babbf941c9, 2ed7087c8d).
• Language-change sweeps touching these files internal — new/make split, composite-literal syntax, closed(c), error type, float/complex deletion, map-index rule and others (5564504507, 9f8f2e6130, 3f915f51a8, eb6929299b, f2b5a07453, c7122a3c58, 062406bc64, 1fe42e2d4d, b54133d200, 839a68469b, a50cbf6c73, 8a7cbadbbe, 40621d5c0d, ca6a0fee1b, 20011bc878, 0496040bd6, b5c57fea96, de13727f0f, 00f9f0c056, ef12ae4631, 1f6463f823, be2edb5761, 535dcf77c8, 907509de4a, 387df5e176, 85fea81d70, 73120ee81d).
• Runtime printing and low-level fixes internal — traceback pc and %S fixes (ec913c42b3, bafd1787fe), misaligned-stack printf (e339d27db7), printf locking and nil-map printing (fb1bcd47c6, cb9c973829), string-conversion race (77f668a0f1), 386 guards (a52fb815e4), map size not multiple of 8 (9795c9e727), strings via cgo-style runtime (fa40c856ac), math moved out of runtime (488ca3c7a6), copy bug (948f3e77e1), complex divide matches C99 (21ff75bc0e), strconv and protocol buffers using reflect (079c00a475, 091fb779a1, 1b3299ed0b, d4e57ff248), formatter work (3a7df4dde0), UTF-8 replacement rune (9ddeb2105f, 3619f1ea6a), cgo helpers (95fa16a892, db9229def8, e1cfb6f3a9), build artifacts (d0abe4cbb2, 2f5a05a859, 47580f79b4, f1547e511b, 87b1124407, b90960e01e, 6e0767bb04, 90564a9256, 175dd773e6).
• Compiler metadata fixes internal — non-methods kept out of xmethod list (11075ed893), no pkgpath for error (ee09a8cd9f), unsafe.Pointer kind (454f03ff0b).
• Early reflect API history and misc runtime internal — printf via reflection (418b97c670), CopyArray to CopyFrom and removal of “open” arrays (c5f99ccbdd, 9a7332fb5b), IsNil/NewZeroValue (a8f6e38bce, b66d703941, 2d5d4a1b41), interface set and Get (92e925778e, 97f3a80d93, a8a678fc2a), DeepEqual type/nil checks (64627b04fb, 33be0c6465), typestring.c removed (dbc6d91d70), sys.Reflect moved to unsafe and unsafe.New/NewArray introduced (c367d1b789, 33649bd278), pointer-scan optimization disabled because reflect and gob broke it (ed6fd1bcbe), type assertion rules (49e2087848, 955638e2fb), printing of -(1<<63), unknown types in panic (68209ed5e3, 1dd0319be3), misc (bcd6403cc9, d47d888ba6).
• Unicode 5 update internal — Updated Unicode tables to Unicode 5. (5b904a3bde)
• Early reflection library updates internal — Updated reflection for the int/int32 split, adjusted sys.reflect/unreflect for large objects in interface values, and made assorted cleanups and func-rule updates. (282493bbf6, d0e30cdaa9, 484ba939d2, 4cf7711568)

Diagnostics and knobs

From Diagnostics and knobs (Go 1.0–1.17)

Everything up to Go 1: runtime/pprof CPU and heap profiling, runtime/debug, pprof.Profile, GOMAXPROCS/NumCPU, gdb support, in the profiler and pprof threads.

• CPU profiler and runtime/pprof writers (legacy format to compressed protobuf) — Done:
  • 2009: user-visible runtime.GOMAXPROCS (7955490de2).
  • 2010: malloc sampling and a pprof interface (6eb251f244), heap profile extra information (baf538406b), MemStatsType (87915b6565).
  • 2011: user-visible runtime/pprof CPU profiling (b47ec598b7), pprof deadlock fix (bed7e3ed78), OS X documented as broken (d0eaa58b5a); runtime/debug package for stack traces (89993544c2).
  • 2012: user-visible pprof.Profile type for custom profiles (ebae73bb24); runtime.NumCPU (6dfdd4c1e3, 0ae9d812c8, 610757b155 removes a duplicate pcln walker). Left open: nothing noted.
• Heap profile accounting and MemStats — Done: MemStatsType (87915b6565) and a malloc sampling profile (6eb251f244). Left open: nothing noted.
• GDB runtime support — Done: gdb debug info for builtin structured types and pretty printing (9a71bb00bb); goroutine support and fixes for strings, channels and missing types (db22e236fd, 43512e6c70, 46ed89b7a3, 8a4ef5d1eb, fb2706113f). Left open: nothing noted.

Other changes

• Small API and doc items internal — finalizer and SetFinalizer docs (5958fd7f89, 78d19b9b73), GOOS/GOARCH constants and FuncLine fix (4e64555894), NumCPU reference (a03c519a8c), gofix error rename and build cleanup (eb6929299b, 2050a9e478).

OS layer, stacks and panics

From OS interface, stacks and panics (Go 1.0–1.4)

Everything from the first 2008 runtime through Go 1: segmented stacks, signals and tracebacks, Linux/Darwin/ARM/386/Windows/Plan 9/FreeBSD/OpenBSD ports, cgo and runtime/cgo, mutex unification, vDSO-free time, GOMAXPROCS and thread startup.

• Segmented stacks to contiguous (copied) stacks — Done: segmented stacks and goroutines 751ce3a77a (2008-07); traceback across segments d3204ef19f, 44f65c8f08, 4b376ef328; fix for stack-limit register placement 24838a2df6; 32-bit stack-switching fixes 5273868f67, aa3222d88f; stack overflow debugging add89dd1ba; stack check added on all OSes 5a4a08fab8, 0400a7f8b1; cgo stack guard fix for >8K C stacks fbfed49134; linker stack-split logic near the default segment size 9e5db8c90a; GC race on g->sched.sp/stackbase/stackguard while in syscalls fixed by saving a consistent triple g->gcsp/gcstack/gcguard in entersyscall (370276a3e5). Left open: each split allocates a segment, so hot-split behaviour was not addressed.
• Stack-split prologue, nosplit budget and C-on-Go-stack detection — Done: stack-limit setup bugs 24838a2df6; 1ed7f18165 better calling of morestack; stack check everywhere (5a4a08fab8). Left open: nothing noted.
• Panic, defer, recover and Goexit — Done: panic output and tracebacks for all goroutines (3835e01d97); array slice error includes bounds (9b8a6dc7da); runtime errors become real runtime.Error values (63e878a750, “type assertion a runtime.Error, the first of many”); divide by zero and nil dereference become panics via signals (5963dbac08); deferred calls run at Goexit (83727ccf7c); startpanic so only one thread handles an incoming SIGQUIT (55a54691f9); no breakpoint on terminal panic (59ce067da8); distinct panic message for calling a nil func value (5032a7dc0c); signal information printed during panic (12307008e9); range+panic line number fixes (12a5774cde). Left open: nothing noted.
• Tracebacks, crash output and GOTRACEBACK — Done: 2008: first traceback aeb43984ec, segmented-stack traceback d3204ef19f, source lines a5433369aa, format d040d26863/2b39165f1e, all goroutines 3835e01d97, stop when PC leaves text bad8c3d5dd, PC fixes ec913c42b3. 2009: call-instruction accounting dbecfbf86d, 63810f840f; correct pc in fn+%#x 4962e7ee9b; 386 32-bit hex a65bf95dd8. 2010–2012: ARM traceback 6c196015e0, 7081e67565; argument dump 7eb13b95a3; crash trace on amd64 befecf6b59; creation PC 324cc3d040; traceback through active lessstack 4b376ef328; omit breakpoint on terminal panic 59ce067da8; GOTRACEBACK=2 48bd13911d; runtime.Callers 2b7d147f1a. Left open: nothing noted.
• Symbol tables, pclntab and runtime.Caller/FuncForPC — Done: pc/ln table printing a5433369aa; history-stack decoding 84852fe220; runtime.Callers 2b7d147f1a, runtime.FuncLine fix 4e64555894; ARM symbol-table size and leaf function handling 6c196015e0; runtime· prefix on all runtime symbols to avoid collisions with C libraries 68b4255a96 (symbols left alone: cgo names, linker-known names such as pclntab, epclntab, symtab, esymtab, text, etext). Left open: nothing noted.
• Signals: handling, os/signal, foreign threads — Done: 2008: signal handling and registers aeb43984ec, 206daeabda, 3311e1b673; SIGSEGV/SIGTRAP details 6e8dbc2051, ab9f27b227, a67258f380. 2009: SIGPIPE ignored 2cf5c809d0; os/signal b5866494ea; crash by default 08579c26dd; sigaction layouts for 386 and linux f529224039, fd5fa4b301. 2010: snow-leopard kernel bug workaround (2f0cae46d8: OS X forces gs=0x37, so threads without USER_CTHREAD segment fault on IRET into the handler; fixed by using thread_fast_set_cthread_self); 807605d0fc; 386 handler bug 53a529ab2b; 68b0a87966. 2011: print signal info 12307008e9; signal stack bug 820dc9ff1a; 8698bb6c8c turns “too many EPIPE” into a real SIGPIPE; 5690ddc7fa no panic on SIGILL. 2012: 35586f718c, 55a54691f9, 1707a9977f (fix FP control word on all threads), 240b1d5b44, 224f05ba88. Left open: signals on foreign threads not handled (diagnostics only: b23691148f, 9b73238daa).
• Threads, locks and the OS scheduler interface — Done: 2008: Darwin threads 376898ca8b, GOMAXPROCS semantics efc86a74e4, semaphore use 5ff12f871f. 2009: clone/futex 770b872752, CLONE_PTRACE removed 89f8238a99. 2011: Linux mutex 4e5086b993; chan finalizer removal d770aadee5; unify ee24bfc058; parallel GC enabling osyield/usleep on all OSes (d324f2143b, 40c26fff14, 723f73caec, d573ad2671); goroutines during init d1bafffa4b and main-thread lock 6808da0163; runtime.ncpu on OpenBSD/FreeBSD (b2f1eba324, 12bf00054e). 2012: cputicks 8e765da941. Left open: runtime used 1:1 M:N without per-P state (scheduler redesign is in another area).
• cgo runtime support and non-Go threads — Done: 2009: FFI start fdc4b4a47f; cgo 133a158bd8. 2010: runtime/cgo b07b04d35f, 7eeebf49be; export 2d0ff3f1a6, 2e20386fc7; initcgo on all amd64 a4f8d36ba5. 2011: SWIG 17d50d8664; reorganization f9ca3b5d5b; pthread_create error check a026d0fc76; os.Setenv updates C env 623e7de187; fast cgo 72e83483a7; cgo build without cgo c02423902d; g0 stack guard fix for >8K fbfed49134. 2012: signal masking in runtime/cgo 1fc9a17c7e, 9eeb90945e; diagnostics for callbacks on non-Go threads 9b73238daa. Left open: C threads cannot call Go.
• TLS, g/m registers and shared-library linking — Done: bbcb91a3a7 %gs; 2d6ae385e1; 9569c67a6b Windows TLS slot; 7e77623120/e42788628a^1.1 Plan 9 TLS (G and M relative to _tos, later PID from TLS in 1.1); 1b14bdbf1c nacl (ldt0setup sets GS itself). Left open: no shared libraries.
• Clocks, vDSO and timers — Done: c19b373c8a, 8dee872963, 3b860269ee, f437331f80, efe3d35fc5, 8e765da941 (cputicks seeds fastrand against hash-table complexity attacks; RDTSC on amd64, constant 0 on ARM). Left open: the commit says “update 8a to recognize RDTSC”.
• Windows runtime port — Done: 6bfe5f55f4, e00795859b, aae5f91213, f0b8f84d37, f83609f642, 9b011500c0, 9569c67a6b (TLS via ArbitraryUserPointer), 9fd26872cb pprof on Windows, b873701dbd callbacks not GC’d, 428062da4e. Left open: cgo on Windows via ld flags only.
• Platform ports: OS and architecture matrix — Done: 2008–2009: arch/OS split aeb43984ec, fcd76f7dc9, 878822f355; 386 0d3a043de9, 4702c0e5ef; ARM start 7943556970, be639b9a51; nacl 1b14bdbf1c; FreeBSD 0489a260da, b3f538a4fd, 5a4a08fab8. 2010: Windows 6bfe5f55f4; Plan 9 99a10eff16, 8221eb9103; ARM softfloat 7c2b1597c6; nacl removal 0c54225b51. 2011: OpenBSD 21ac258e07, 9ef17990c2, 1075af0cce, 8aa2591b13; windows/amd64 f83609f642; NetBSD 26089cfe25, 728c16cf13; godefs->cgo dd2abe5152. 2012: ARM OABI error bb40196ebf. Left open: nothing noted.
• Startup, auxv, randomness and security-adjacent runtime details — Done: 8e765da941, 3f7a32405d warns on SELinux mmap failures, 65b036c381 avoids doubling memory on grsec kernels, 102274a30e sizes arena to fit address-space limit. Left open: nothing noted.

Other changes

• Early runtime structure and portability (2008) internal — explicit install paths (54bca54655), os.Error now echoes call context as PathError (a0bcaf4c00, user-visible API change in 2009), a revert (a41d85498e), execute bits cleared (504963e6a4), goos/goarch split (2b77d87fca, 28429aaaa6, 959f9fb3d4), ANON flag difference darwin/linux (fa259ff89c), print PC on faults (88a3371a91), signal interface code on linux (12c2864e4f), PC/SP tracking checks (d4c2da409b), runtime as archive with Makefile (c87597de2c, 9ff0e6288e), sys.readfile/writefile and args (3e4e83ab1e, 66b240c7a4, c870ac239e, cbdaa10f8c), runtime.c broken into per-topic files (8e82a673db, ef12ae4631, f28ec1af7f, bcfd31f0e9), dead code and cleanups (b07e084a99, 1e774d9e6a, 90da636c15, 873ba78b79, e9047d1fc2), acid debugger support (c8dee2770d), removal of array-bounds trap handling (c1ad0509ee), “when main.main returns, the program exits” (ebd1eef41e), exec preparation (dfa5893d4f), bsdthread_create arg (7ca5a0d323), printf check, off-by-one source files and printarray (5bb0c4f88b, 7df571aef7, 61e0fcce8a), races (53e69e1db5).
• 2009 runtime organization and ARM/386 bring-up internal — sys-to-os/runtime moves and docs (918afd9491, 4f21161269, 3f6acf1120), Makefile work (63c2d52117, ab7a8d43a4, 090efde407, d281748a6d, 285b6021e9), missing syscalls (528919520d), SIGCHLD race on darwin (cd80000d8d), ARM details: Gobuf.r0 (111005d32b), stack-only in-params for 5c (46e392e01c), registers (bcfc6e631f), syscall convention (6f91ba1b0f), closure cache flush (6dbd142951), ARM memmove (744d5ae48a, 093493c6a5, d08d33f389), cas/getcallerpc (d58b5fca45, b83549a7e6, 33a7bcf315, a2cf914379), newproc arg copying (03bbfe6724), cgo2c padding for the new output-arg alignment (88e7fd5410, 150a64572b), reflection for functions (bba278a43b), FreeBSD signal structure differences (7ada6018a7, 1444f1bb1d, cdce7325c8, 659780b643), Darwin thread start (e1c5c3df77), misc (3ff5e727e2, 32e979c0de, 41554e2528, 597b2a91a6, 857d4cf1a9, a23746ea65, 4c0f262a2d, f39fcd7e42).
• 2010 port maintenance internal — tiny/embedded targets (9f5264f299, c0aac20e20, 129c6c14d1, 1b6282a799), malloc instrumentation (e4f06812c5), build fixes across FreeBSD/NaCl/Windows/ARM/Plan 9 (de90a7d4aa, 2b4a9fa176, a24cf69fd8, 7ecefdc03f, 059c7ba996, 636342292c, 89e9231865, 5b7e50a0aa, 9cc8e9ef48, d10963b6d7, 4fd12c04c5, 2b18b18263, 555feea117, 60c91bbf4c, e04ef7769e, 33405ecc86, 3832389036), NaCl closures and defers (c6138efbcb, 9ce0eb2d07), Windows details (d5a8647d80, fdb460ec11, bc4a9caa41, b611137098, 7f9e247489, eee095399f, b0c6bba8e8, 9f77e7ea3c, 70deac67cf, c83451971e), print of floats and fixed strings (26e846429d, 4843b130bb), darwin bsdthread_create failure message (718da3339a), Leopard 16-bit divide fault (c9172fb2a3), ARM fixes (fa4da33315, df88fc6109, 2012604002, 079cbddbd8, 85d9ab61d2, 7e69c90ade), GC manual stack (d4cc557b0d), SysFree stats (929fdd860b, a2450c1456), runtime file splits (e63ae242e6, 35f8a3f90e, 340f28deab), writes ignored on failure during print/panic (b3e8fdce8d), GOBIN/GOROOT cleanup (5c603dbb75, 1fab0cd12a), debugging help (7e14bd81f4, 45e12c7cd3, 7c99dcbdf9).
• 2011 Windows, ARM, Plan 9, OpenBSD maintenance internal — Windows callbacks, stdcall and SEH details (239ef63bf2, 12bdb29bdf, ff7d7b271f, c4206cb231, c3be760889, 6b648cafde, 9c774c3f26, c8ee9c60d2, 2a80882601, f627215bab, ae891b5528, 7406379fff, 6bc0346e28, 603d80c28d, 0d37998a06, 6d4c18a4af, 78479163cb, e7042418c5, 6876ad37f3, ad29ef9561, 4fa6d57f6e, 6c240d7671, b7949035d6, 6606995c91, 38d3f58528, 89cc4d7814), ARM (1f2234633f, 079a5cffb3, 90d8c8a09f, 1fddbab736, c475c3071a, d4a9bce70a, 141a4a1759, 7f5ae484eb, 6b3357129a), Plan 9 (ceef10c222, 0924185840, f7d754fcce, c1f035ba4c, b546f50716, 528ccdc513, 4a2d30e13b, 1cb254a085), OpenBSD/FreeBSD (c7f6f9f318, cb2040b2ab, a1c622dfea, 85b7419211, 13dc53055f, 0e5cd9d3f6, be8025604e, e5437ab065, 1c05a90ae2, db89e19d26), memory and malloc (4608feb18b, 5b1b2ba9c7, 591c74ad20, a8bf6f32cc, e4492ce3c3, 47410a2490, 439694125f, dde435587d), Darwin thread VM footprint (59a8926829), Mac OS X 10.7 cgo (95963e6294), print and goc2c (f9fc1ddf75, 5f40c5b384, 3693cd2988, bed7e3ed78), cgo runtime (b97005c1d3, 1c42db8835, 0cfa0fe242, 90294a08c8), versioning and GOOS (bc874ec0dd, 31ccf19612, aee6b1160e, fd0cf08748), 3c7104479c drops CLONE_PARENT, c14b2689f0 faster finalizers (38-96% depending on core count), 85916146ea fixes linux/386 usleep and re-enables parallel GC, 31452a3618.
• Build system transition (Dec 2011–Feb 2012) internal — runtime build made friendly for the go tool: separate auto-generated files (851f30136d, bd9243da22, 86dcc431e9, 55889409f8), go builds runtime/cgo (54fb9940cf, 41a6165c03, e83cd7f750, a462816753), Makefile ordering and cleanup (e628144aeb, 3800b14071, 3435438948, bacb1b70f7, 56e6a02490, 961f96b5d2, 0ae6084fef, 9a15c2186c), math assembly stubs (dd8dc6f059: one Go file declares Sin and a lowercase portable sin, each arch has a tiny assembly stub, so godoc sees one declaration), 13b26cb36a, 2012 fixes (1250f94f93, c30ba7e65a, dff5535aaa, 8542dc0764, 0bd53d2ce0, 7c2607a91d, 2d53d227f6, 07a2989d17, 1064f3a97b, b8f465644c, 22c41ff019, 51a84bbfaa, b0beeb1501, 36aa7d4d14, 8a1b3d5a57, 2d3cc97c9c, 16ade99d9d, bd6404a4cc), OS X CPU profiling (6e2ae0a12c).
• Runtime symbol prefix internal — all runtime external symbols are prefixed runtime· to avoid conflicts with linked C libraries (printf, malloc, free) (68b4255a96, 718be3215f, e8605b1279).
• Memory interface (OS side) internal — SysAlloc/SysMap/SysUnused/SysFree per OS: MADV on Linux/Darwin (e6f5a90b5f, c354f93b93), SysFree fixes on Windows (4e69976a60), MAP_FIXED on 64-bit Linux (ddde52ae56), FreeBSD mmap (e1e829b786), nacl chunks (1b14bdbf1c), 2GB malloc (d89b357f76), mmap null page (649aab835f, removed 951318c0df).
• 386 FPU state internal — FPU set to 64-bit precision on linux/386 (cc1556d9a2) and on all threads (1707a9977f); DF flag reset (f85abf01bc).
• Hardware/atomics internal — native xadd (491aa1579d), cas on ARM (6a48aab747, 9ad9742157, 540feaae47), 64-bit atomics (4667571619^1.1, 1.1).
• Go defs for C structs internal — parallel Go definitions of C structs (85cae877f5, 7400be87d8).
• Misc runtime OS plumbing internal — GOROOT/GOROOT_FINAL (0c3a93ceb7, d3ac545f80), runtime.Compiler (4e110af169), runtime.write back to C (c9e5600f7d), no malloc during malloc (fc7ed45b35), Itab data race (86a659cad0), memmove replacing mcpy (fe9991e8b2), os/signal Incoming SIGCHLD (43d2e59a81).
• Func literal equality user-visible — every func literal expression allocates a closure so == on funcs is consistent (9346c6d901).
• Early runtime development: segmented stacks, scheduler, locks internal — Updated darwin for segmented stacks, rewrote the lock implementation, adjusted stack growth with coherent SP/PC in gobuf, and removed sys.sleep. (3719aa4d9a, 96824000ed, afd04fdb98, 7343e03c43)
• 386 port and runtime renames internal — Updated 386 to the new runtime and renamed sys functions to runtime. (8522a478bb, 22a5c78f44)
• Softfloat stub and runtime cleanup internal — Added a first stub for softfloat that skips float instructions, moved memory code into GOOS-specific directories and allowed printing of static strings. (d85bb81878, 12518e441b)
• Windows improvements internal — Multiple Windows improvements and cleanups, and a fix for stack cleanup on windows/amd64. (62afa225af, 0f5902d6be)

Compiler frontend

From Compiler frontend (Go 1.0: 2008–2012)

The compiler frontend went from a prototype tracking a weekly-changing spec (semicolons, chan operators, export keywords) to the Go 1 language with a separate typecheck pass, exact constants, Eface interfaces, closures, escape analysis, inlining and a stable textual export format.

• Lexer, grammar and statement syntax (semicolons, chan operators, conversions) — Done: user-visible everything above, in chronological order.
  • 2008: optional semicolons (8200a0b088), a,b := fun() (81b325db1b), new chan syntax (ac048ce7f4), send/receive operators (47919799b4), semicolon rules (d364d28142), *T as implicit declaration of T removed (02d184b303), trailing comma in braced lists (82e41cc533), DOTDOTDOT (74427c6346), range (26b357ca5b), chan/map no longer pointers (dc7b2e98d2), T{} / T(x) (0194aaf918).
  • 2009: composite-literal paren syntax and back (07244f7c80, 49cc649e59), type switches with case nil (a4a10ed856, 0f469a99a3), lexer-driven semicolons (8abcdee175), conversion rules per the new spec (7f3eb2738f), no parens around type in struct literal (9c3c140984), semicolon/package-clause rules (aaaa1fc69b), x[y:] for strings (aa4c638b7b).
  • 2010: //line directives (444066e56d), EOF semicolon (ec13ed1fce), select case expr = <-c (9b62461a8f), new slice spec (fce222a95b), improved syntax errors (2a01d72878, 78c27ed650).
  • 2011: if needs a condition (52943bfe4d), else needs braces (58e19aa4cb), non-blocking send/receive statement syntax removed (cb584707af), x, ok := <-c replaces closed(c) (8bf34e3356).
  • 2012: switch _ := v.(type) rejected (74ee51ee92), diagnose (x) := 0 and similar (112267d55e, 2011), top-level var/const rules (4bcc9c6b5e). Left open: nothing noted in the commits; the C yacc grammar is still the parser at the go1 tag.
• Package system, visibility and import resolution — Done: user-visible
  • 2008: export adjectives (989676d2ba, 695f83a9e0), package locals (d3f6093931), autolib (e90ae879d6).
  • 2009: case-based visibility and the removal of export lists (07d344e442, 06869eedf9, 61590c4c44), -I (062d6998ab), whole-package compilation (66bb399fdd, see the typecheck thread), unused imports (73e52ae971), import . fixes (63aeaa2a03, 5a5799f613, 7b240e8135).
  • 2010: global name space dropped (531e6b77c8), full paths in type data (1cecac8134), -u requires imports marked safe (d20ad1c75a), canonical path checks (555f5b6b24, 7e92e1cbfa).
  • 2011: main not reserved (c1a695c160), -p import-cycle flag (1e480cd1ad), package paths in symbol names with period/0x7f escaping (33f1d47b38).
  • 2012: import path validation (dc38756ce1, d0d251f858, daacba5184, cc99d8ad0b), -D for relative imports (604f375110). Left open: nothing noted.
• Export/import data format — Done:
  • 2008: first import/export (2254a8ee99), new format (b8babed7c2), embedded type export (21617250f4), mp float constants (f8797daa9f).
  • 2009: re-export of bools fixed (dec12d3654), unsafe import foundation (1d4daa2d39), import-name resolution fixes (c715b58dad, e733766dda).
  • 2010: complex constants (713e3e1541), export of complex types (cd016d7558), full paths (1cecac8134).
  • 2011: metadata for all dependencies (e6f3aa6c36), inlining-preparation format changes (b536adbfba, 40b2fe004f), byte/rune distinction (862179b0f5).
  • 2012: limits and fixes (aa63a928ea, feaa9ed10a, 5c52404aca). Left open: the textual format has to carry inline bodies, which the 2011 commits say they were preparing; no binary format yet.
• Constants and multi-precision arithmetic — Done:
  • 2008: mp ints (9c2ade358d, 272ae659db), exact large-constant export (2b75556436), mp floats (3fa4610601), (1<<x) (944ad62ecd).
  • 2009: ideal bools (a95ee61aea), ^ on consts (b8be809c10), shift checks (0aa1b1508a), float/int64 conversions (1620023d03).
  • 2010: complex (33d6a260c1, fc010adcd7), precision (95b93c28e3, f6b93ab432), const simplifications (ed13d39972).
  • 2011: denormal rounding (cf63e34b1d), shift rules (5ab096d030), character constants (be0ffbfd02, Dec).
  • 2012: ideal bool dropped and relaxed (126d475a43, e29d3dfc49), shift overflow (79db6ada48), len(array)/cap(array) constant rule (d4fb568e04). Left open: nothing noted.
• Typecheck/walk separation and package-level declaration order — Done:
  • 2009: typecheck pass (9271c6402e, 9dc22b6d6f, d8c19c80dc), lazy declaration processing (dbe004efe4, 54b403723b, 2609731736), no forward declarations (b648716ee9, a92610208e), whole-package compilation (66bb399fdd), per-file filename disambiguation dropped (107d404378).
  • 2010: spec-mirroring conversion/assignment (565b5dc076), less aggressive name binding for line numbers (76da2780c3), types inside function bodies (17f90c68c6).
  • 2011: whole-tree typecheck (e59aa8ea4a), cumulative error count (3208917d54).
  • 2012: typecheck-loop diagnostics (2aafad25b4), field+method same name (7dd90621f8), return expression-list checks (1d3ca9236e). Left open: nothing noted.
• Interfaces, type switches, assertions and comparability — Done:
  • 2008: signatures and conversions (ead7a6d47a, 1bf38484d1), interface equality (edb1412c50).
  • 2009: new interface rules (a6ba5ec535), Eface (2da5022bcf), type switches (a4a10ed856, 0f469a99a3), embedded interfaces (b4af09ab56), map key checks (98b34e5bbd).
  • 2010: new comparison rule (23bd214aee), recursive interfaces (44898c7b76), equality algorithm specialisation (4d903504b3).
  • 2011: algorithms (54e9406ffb), error and experiments (2a0e15d36c, 47f4bf763d, ae7a003cf9), map/func compare removed (5bb54b8e9c), struct/array == (196b663075).
  • 2012: zero-size algorithms (1ff1405cc7), comparison recursion fix (427b5bddcd), struct with _ field (c4c92ebeb6), float map keys (408f0b1f74). Left open: the pointer-methods heuristic was labelled a heuristic that “catches the problem” only (4eb7ceba58, 935953a9f8).
• Embedded fields, method sets and receivers — Done:
  • 2008: 61361af9e8, 6fecb76eea, b642cf8c00, method on *T names (258c817a1b).
  • 2009: methods on slices, funcs, chan, map, string (b2dfd787d7, 5e2c05877d, 316d377ac2), method expressions (0d668259dc).
  • 2010–11: 883d68f885, 0b209b36b6, 1bd4b6371a.
  • 2012: 4267974c0b, 987a580b9f, 7dd90621f8. Left open: nothing noted.
• Closures — Done:
  • 2009: 0970c46863, 416b27548e, 941ed00b1d.
  • 2011: 9b82408f6d, 2c4edb0eea, e8ff9a624f, 890bdc5339.
  • 2012: ba25778f3f, 075eef4018. Left open: closures containing closure expressions were excluded from inlining (a62722bba4).
• Escape analysis and heap allocation — Done: 391425ae55 (2009), a75e347a21 (2009), 847b61b554 and db5f9da425 (2011), c45c0c0c1d, bf9c778fe2, 9bf3478658, 075eef4018 (2012). Left open: nothing noted.
• Inlining — Done: 2011: b536adbfba, 40b2fe004f, a62722bba4, 7e6890a670. 2012: 4a6b07f235, ee9bfb023a, 2332439b1b. Left open: excluded calls, closures and ... (a62722bba4).
• Builtins and unsafe — Done: 2008: b2d9020242. 2009: 01c2de0c15, 8a70545b57, 64c3fe05bf. 2010: d8b5d039cd, 01eaf780a8, 9b1507b050, a186b77b03, 3910161307. 2011: 1d687c742d, 5fc3771b3a, 6ed3fa6553, 012798a325, cf9f380499. 2012: 1f2445d27b. Left open: nothing noted.
• Channels, select, maps and strings as built-in types — Done: 2008: cb9b1038db, 79fbbe37a7. 2009: 3657061550, a91a8042b4. 2010: f47d403cb4. 2011: 5038792837, b0543ddd8a, 65bde087ae, 3770b0e60c, 6b2ec06587. Left open: nothing noted.
• Initialization and static data — Done: 2008: fb3af53f4e, 1ea5bc7533. 2009: b91a043d02, e2613711aa, 0631d65dc5. 2010: 33da9afc3e, d348971103, b3dd22fecb. 2012: 896f0c61c8. Left open: nothing noted.
• Composite literals — Done: 2008-09: 4539ced714, 182f91ffe0. 2009: a016081f43, 18840f5429. 2010: 8ffc4ec5d0. 2011: 7dc9d8c72b, 5cb1c82d96, bf899befdb. Left open: nothing noted.
• Variadic functions (...) — Done: 2008: 74427c6346. 2009: d122bb2193. 2010: 68796b0270, 75dd8fdb34. 2011: 2795b13156, 5b62ba14c4. Left open: nothing noted.
• Statement and flow rules — Done: 33ee52727f (2008), 59914723df (2009), 7f4c5ea7d8 and c18d1a78a4 (2011), 1d3ca9236e (2012). Left open: the unused variable check was disabled when added (59914723df).
• Diagnostics, error recovery and compiler plumbing — Done: as above in each year; 2009-03-30: portable code moves into gc (bac922c6e1, 5e792b6c09). Left open: nothing noted.

Other changes

• int becomes a distinct type, arrays unified user-visible — “the end of life as we know it: int is new type” (c21d9a1ec9, 4a3ce5f19e); the static/dynamic array distinction is removed (c6130e9f1f, 66a603c986); declarations of type map/chan/string must be pointers until the 2008-12 pointer removal (c7ab332744); *T shortcuts and [...] fixes (c458c98388, a1391c2d13).
• any as a compiler-internal type internal — any demoted from reserved word (e1a06ccc80), disabled outside canned imports with a -A flag for mkbuiltin (30f2799f88), then allowed in any import (1ea28570ec) and finally checked outside the grammar (903d28bd1e).
• Export-syntax bug fixes during the 2008 rewrite internal — method sort order, inheritance syntax, incomplete types, interface prerequisites (dc04d096f0, 1101d406ec, 5f0a5e7a13, bcd07252e1, 8545700af8, 9f3d600be6, b033c581db, 59167e5bdb, ba46bd1e5a, 73dd4a37f9, 655c281303, 2d7eecbbf4); %Z string escaping for tags with quotes, backslashes and NULs (dc6bd11ce8, 57804f1d2d, 8a1ad75644).
• sys package scaffolding of 2008 internal — runtime-facing helpers added to sys before builtins existed: argc/argv (2987c8434b), bytestorune/stringtorune (6db99de606, 7ee60b174d), writefile (c870ac239e), caller (a3ed4e716a), float bits (335a5236e7, 2f4d35ffb9), plus early coroutine/channel runtime hooks (0d079a5362, 3856e45e03, 97cab903af, 2d9ff40774, 120827284e, e5d9a5c9f0).
• Type identity corner cases internal — method function type comparison (0be746d581, 689b28fd96), embedded vs non-embedded field in eqtype (aa7bd48389), struct field tags included in type equality (2fc0b4f01b), infinite recursion in eqtype (282bf8cc8c), duplicate method-table entries (2d5e732c54), anonymous interface method offsets (6aa85d1cbe), sub-pointer-size receivers in interfaces (607eaea456).
• Portability and build of the C frontend internal — Plan 9 build and warnings (12995e2d35, 4ca2172f38, 4ba677c6ea, 5f132b93eb), Windows detection and symbol tables (3bcef5ac30, 69a2e1dc52, 77a70ddb7b), bison on FreeBSD/clang (1cb951d994, 859ba57bbb), makefile and environment-variable removal (6609d2f88d, 4f8117d9eb, da392d9136, 5c603dbb75, 857d4cf1a9).
• Remaining bug fixes, error-message and diagnostic tweaks, 2008 internal — 95 small commits (test/bugs fixes, syntax/typecheck error text, line numbers, printing, crash avoidance): e372be9e76, 609cf0c3a7, b6218e6907, feb1c77f9c, 36bfd2a906, 27d95f1372, 610644a1ca, 9abf9e8a37, f9c58c25e0, 0b3093f0a5, 32aa0d9198, e2e6b7e4cc, efec14bc5a, 53ec6500bc, 504aa698f7, 7131bf476c, 75937c2a16, 102fcc6689, 57d80398e6, 4d6d4e7f4e, c6e8e1cebf, 44b8934d35, 9e2d185040, 0ca551fc36, 963753d3f9, 05caa7f820, b1abcc195d, 67c4cc473c, 091047f36c, a8a9dbc9c6, 4797523572, c1ab5a554f, 30fd44cf9d, a7f1af81bd, 9c5669bd0b, 9dbaab54d1, 1ae08bee90, d01a1ec260, 721cb9c6a1, 13f3149a01, 39a4b1421f, 4332e0a546, 5383e28ea0, fb86c39362, 7be2b9fdf6, b6f59358b5, 4d571c9093, 8dc08788ef, 53a22770a7, 45f4e38506, c8b9970e16, 1b257b2bb3, 96da920f1a, 0adc1db757, 1836541566, 4248607ffe, 7cd173a4f8, 2e4b8d94cd, 1163b1db6f, 28912ce03f, 1a149ca1be, 0347e95b63, 14c639161a, ad48706a24, c14c961ae4, 6d3d56d55a, a3cdd2e802, e8278bcb29, 4fdf3d6247, 2f5a05a859, 2c050571d8, e5d9a5c9f0, 0eda21a2fd, 792145723e, a1585b676b, 10002bb0fb, ffafad1919, 28a30254e7, 92a1190c6c, 8bce3b5658, 57bd0da375, 7dd62cb3bc, 5f1a3be9dd, cb64ec5bb6, fa945d5bf8, e683fb7a54, 42d89ac02c, 99435cac09, e53d5ad620, 697cb17b30, 4026500d18, 92f74ca7e2, 9786f69f74, c4416ac06b, cbff09d666
• Remaining bug fixes, error-message and diagnostic tweaks, 2009 internal — 110 small commits (test/bugs fixes, syntax/typecheck error text, line numbers, printing, crash avoidance): 20595ac4b0, c1e7e270f1, 3c5f3a8641, 4efad58d0a, f1fe21a08f, 5b129cda5f, 1e1cc4eb57, 4b8e030762, 6e395cfecf, 360f0aacee, aab26a5248, b0009bef20, d3d0c256be, 3c0fc400fb, 63985b489b, 6eb54cb05b, 5fbadf0bc3, a2cbc2998d, e224b1ebdb, aacdc25399, 58f5f4f18d, 07687705a4, 39436f2a74, b03b541b7a, ad36c39211, 7a98315c96, f821e3c7c3, c4de24981a, b5e212ffdd, 88a1aa8e1a, d4fa253837, 2a4dcfffc9, ca2fe5d8bd, 4beac9985b, 850cd6a2fe, b46e7c4d3c, 18890eebbf, 0a6d83567e, 3b37b02834, fbcbcdbb1d, c17ce9f94f, 2f2577a4f6, 30a28aec25, eba82f4391, 0aef57e37f, 466dd8da4e, 4bce6d455f, fa6df47986, 5851a1b5ad, 480f51243c, 9435dc2bdf, 5d5904bb4d, db312fa8de, 53ebd163c6, 7af032b87b, ef4ddd63f8, a1b64821f8, 42af80348c, a68b1da3cc, ed124a971e, e11447f7da, 6e1ad041f7, 1d51978fed, 5a74c0b6ba, 059bbdd340, a587d9a73f, 9953c48dc4, aa347c4a0d, a121410541, 468f244416, d1ee5d6e8f, 7732f79daa, 866b272336, 3e98a40793, d594639087, 5600435fe4, e1c5d179d6, 59e2e54eab, ac9d833c1e, ef3e6810b8, 14be733a25, d66d65da96, 27c4e7e74e, bebe06a784, ee2d5128d6, 7a0f4cac03, 32aa5be6ef, e780fa8669, 83bdb805a2, f4ee9f133c, e7f9452da5, d515063588, 680ee6af63, c736b6579f, fd76b4f385, 8fffa1d698, 4c3a85d73a, 1be74762c1, 62c4818ee0, a15648658f, 60ff8cc86f, 71983af4a1, 7932950844, 8c3d2f015b, e5636d6e27, a338231526, 8777759f59, 3997495dc3, 5d754bfaea, 5f132b93eb
• Remaining bug fixes, error-message and diagnostic tweaks, 2010 internal — 76 small commits (test/bugs fixes, syntax/typecheck error text, line numbers, printing, crash avoidance): c6f4d68667, 1b1f39eb86, 307a899d5b, d668d4fbbd, 07fc145744, e0059ae811, 8e996304f3, ff6e310b00, fd150e77e1, d1b14a6fb0, 5f4c052e2d, 288c1c83d9, 0bd41e2ff0, 674458e1c4, 1ca39fb1fd, 5ab8f00bf8, 4589c34580, 80a14df122, f015c53ada, 4408659e81, 5d0ec6c076, 5d230418c7, 2379fdec04, fe7826858c, d97bbabbaa, 4ba177ae36, d6e4e18c8c, 10eb76b04e, 77817e08d5, b5f54db359, 32df678894, a3a0a5fdc3, 6dbba67214, d2aa74118c, 80ac15ec12, 5e253645d2, 43c0a46ac6, 2e9b67afa6, 8c2bc4419b, ea941f09bf, 98b27814ae, a212d174ac, 9f002f6892, ed39c764b8, c9f83372d8, 691d765121, 08a263a991, cdb446feb5, b693847ea8, 0decedf636, f20c2e1cf5, 491a3ca5b7, c6cb303a8a, 585eae3bce, a9a62eef6b, b1311cbc93, e24910d09b, dea283750b, 5baaa490d6, c3900387db, abb73a4a86, d19fcd0784, b1f44a120f, 00ffd59c1a, 52d619cfdf, a3c682267f, 42c26b734c, 2a7019894a, 0db8d3df4c, f0d174b776, 1ee4512b98, f980577064, 1f6b6ca9ba, 603f9feeec, 9e26c4bd1a, 3a2ba994b6
• Remaining bug fixes, error-message and diagnostic tweaks, 2011 internal — 58 small commits (test/bugs fixes, syntax/typecheck error text, line numbers, printing, crash avoidance): 7e84666df1, 05b9050bda, b57ac97c27, 6e03ed32c7, 7da86983a8, 4c052844dd, e39dc76884, 35c880b1e2, e7c4a6dfca, 017e73c1b2, bd77eedacf, db7a2024f9, ec735c4ec8, f10a7882c6, 256df10eae, 7879d3118c, 815a1b84c7, 3f335f80b4, 67b4db9e9e, 7c19d88b0f, 17ca32e9db, e852202f37, 6aaa86ff66, ff4518da17, 13d048a221, 8cf8806d31, 33ff947cac, 12995e2d35, cce10dacc6, 49b70d01c0, dec8009fe8, f91eb3c2f9, 2f8190a8f8, 032ffb2e90, cf79411b1d, 4ca2172f38, 4ba677c6ea, 8b92066e31, 29a5ae657f, 2e1bb76f9b, 986ad31b2d, d5a5855ba1, 40afe58692, 8e515485e2, 882368939c, 7a42dddbe6, 0c64972dd1, 2ab9bb6aaf, d56ca13c03, 0f4f3c6769, e1b1a5fea2, 7cf4825425, 3c638f2892, 1f6d130b14, e14d1d7e41, 5b2f8d96ce, 1d0f93b4be, fd1c1b9679
• Remaining bug fixes, error-message and diagnostic tweaks, 2012 internal — 13 small commits (test/bugs fixes, syntax/typecheck error text, line numbers, printing, crash avoidance): a15448d65e, 556258e57b, b16f3a2d50, 9523b4d59c, 18ee75ec88, 46e7cb57c9, 290e68b983, bf0c190343, 8039683cef, 0b9f090861, 7ac03695f8, 2f3d695a61, 6c7daca236
• Code hygiene and tooling internal — 3adcf6fa0e, f1880579ef, bbb2073223 early plumbing; e1a06ccc80 lvalue/rvalue contexts and any demoted from reserved word; 4e8142c929 maps; d915b96100 new iota.
• Reflect and signatures internal — 44b0ecc5ca, c367d1b789.
• Large data and alignment user-visible — 7e7008fa5e, 67edf9cb87 size of struct{} and [0]byte is 0 bytes, 6361f52fc4 pickier sizes.
• Order of evaluation user-visible — ee9bfb023a, 5efd5624cc.
• Early compiler (6g/gc) cleanups internal — Cleanups and renames across the original gc compiler: runtime function reordering, magic name renames, grammar cleanup, scoping preparation, typecheck split, and removal of dead code. (03febb6773, c249a8de32, c3077f7606, a91af04c06, ae167bf08f, 0183baaf44, af678a593d, e81d97ea84, f1f970ad21, 8f4af6d205, 70a273476b, 2acbc37166, 0dadc4fe4f, ff3a73b407, a2b8e38766, 87f2208bda, 3443656bce, 6fceadbba3, a6736fa4ff, a2a7d473f4, d5a80d0ba4, 0849944694, ab8ed7f8dd, 087bec3dcd)
• Func rules, type rules, signal names user-visible — Updated the compiler to new func rules, new type equality restrictions, renamed packages handling, spec-conforming type switches, and the signal name fix. (28b9702741, 4a43198390, b3533dfd72, 5d16d23362, 6f1698774d)

Middle end and SSA optimizer

From Middle end and SSA optimizer (Go 1.0–1.9)

The pre-release compiler (6g/gc in C): walk/switch/select lowering and a growing escape analysis, first inliner (2011–2012) and the old cgen code generators; mostly bug-fix commits (threads: escape analysis, inlining, order/walk).

• Escape analysis (esc.c → esc.go) — Done: 42687d6ce4 (simplified recursion), 0227c45ede, f2460a8c57, 9bf3478658, 4e78818259, 94ff311d1b (scalar struct fields no false positives). Left open: the whole package was one batch and escaping params all tied to the sink (as 1.1 addressed).
• Inlining (inl.c → inl.go) — Done: 7e6890a670, 86deacc0bc, 93e547a0c2, 81728cf06d, e0b2ce3401, cae604f734. Left open: nothing noted.
• Order, walk and temporary lifetimes (order.c, walk.c) — Done: 2008–2009: fix-ups to the first walker for maps (dee07c884e, 90846cd447), channels, select (949ab5c7ff, bd397d2f9b), convert (52861558f4), eval order in args (0ffacfd995), &T{} as allocation (beee6915f8), new new (dabdfa6cce), range over channels (54aa835b44), slice conversion (65d397f747); 2010–2011: s == "" as len(s) == 0 (c9293f0cc7), zero unnamed returns when the function has defer (d9254d00f9), new len spec optimisation (81c3e8cabc), complex /= (4e5a59591b), introduce temp = nod+tempname (9854fd2a0e), go print (b4bb970e18); 2012: order of &&/|| codegen (5efd5624cc), ninit recursion in order.c (0a55958b52), append inline preserving args (47b6197a01), delete of old map delete (9069721b0e). Left open: nothing noted.
• Switch, type-switch and select lowering — Done: 820f42d977, 79fa5b65cb, 2450c590e9, 6b72b07016, 6f14cada11. Left open: nothing noted.

Other changes

• Early bring-up fixes in the first compiler (2008–2009) internal — a stream of single-bug fixes in walk.c/swt.c for select, maps, multi-assign and closed arrays, e.g. 2bba3a610d, c5bb50c9dc, dee07c884e, 1a7fc7b3a7^1.8, 81b325db1b, f7e2bb55ae, 4c5a165873, 5649c23c8c, 944ad62ecd, 077fe40867, a0e57201c7, d30c9a4be5, beee6915f8, a8b56a73a4, b682f924d7, a0a14b98fa, bf6164719a, 73653841af, f38d2b80a4, b0f627a6e1, 179af0bb19, 3f135be389, a6c59ce274, 3b3e63735e, 0c4f4587d7, 907cb4f1e6, 3067781ab9, 3ea8d854a3, b5e7562191, 47e5152790, a39bae095a, 8b6b380605, 7f3eb2738f, d436a70193, 0417aafe75.
• Static initialisation (sinit.c) internal — a24a26c107 (“more static init almost done”), 0421cf072e (maps), 61c83b6407 (recursion fix).
• Front-end error text user-visible — 769919c4ee “illegal types for operand: EQ” for impossible switch case types, plus d50c70d261 line numbers during walk.
• Misc bug fixes 2010–2012 internal — a3a0a5fdc3, 2795282b50, 17f90c68c6, 31c07dfddf, 01385b400d, 8a2891fc56, 15dcdf751c, e8ff9a624f, 564a1f3358, e1f22bdcc5, 6b72b07016, 93e547a0c2.
• Pre-Go-1 front-end bug fixes (107 commits) internal — individual bugNNN fixes and diagnostics in the C compiler (walk.c, swt.c, typecheck.c) covering select, simultaneous assignment, type switches, composite literals, conversions and error messages (1926fef175, 1a3f944530, 73f85f8a53, ff65872fbf, 47580f79b4, 13f3149a01, 5eb9e0621b, 8a9752dcfb, 3a884d76ac, 6499fbe734, e2e8aa0ee1, dbabeb1d7a, 40fa690d75, 6fecb76eea, 89f341db23, 6b05518553, 90e5574f1c, 83a798513c, 92f74ca7e2, 78fc888e64, cd40cd2435, af5e16cfd9, 85815fe0ad, 84953bdaa8, c458c98388, eed3addb9d, 1b7881adb4, 5b129cda5f, 4b8e030762, 9e735985d4, a81870badf, d3d0c256be, a665e2924c, 955638e2fb, d27e9f528d, 767845b6fa, 1e0c17e294, 1cdcfda140, f7772627ad, 9efd6b8a3d, 1cb3b7d124, 34b6f642de, 190a540892, b03b541b7a, 83e976d53e, b5e212ffdd, 850cd6a2fe, 51ddddc67e, b46e7c4d3c, b3f303ec9a, be63b6dc44, d6a9817051, c17ce9f94f, ea7f5505d1, 75fe1303c1, 6bb3c48d3d, 53ebd163c6, 74b546aefd, 0aa1b1508a, 5ff7d84892, f664d0e904, 03b25a92a3, 811e59f2fa, 059bbdd340, a587d9a73f, 18840f5429, d1ee5d6e8f, 39b12e2dcb, 6be0f50b97, 3e98a40793, 2d73b7f7f0, bebe06a784, 1c9e4b358f, 55edf49a01, 7518613430, c6e316a4b9, 6a4b2492b3, 307a899d5b, fe01d4c8a1, 44898c7b76, 7b5789b584, a9b9afa930, 3908c16ffe, 560283c880, 253fd30e66, b03d7f4d8f, 4c0de303ce, fa3d86ca39, 3f19d8ae8d, 0acb63769c, 0db8d3df4c, cb3754fd43, 2281ca169c, 661bcb773b, de5616fbb4, c0a895fc0a, f58d911698, cce10dacc6, 77f0bdce07, 2d489e67dc, aac144b120, 0d6f857c3f, ea9e93862d, d7634ad7d9, 41806ec26d, 93c4e29605, 0e919ff2c9)

Backends and assemblers

From Backends and assemblers (Go 1.0–1.6)

Everything from the first 6g (2008) through the 2012 release: 6g, 8g and 5g become full compilers with a first generation of registerization and peephole optimization, complex numbers, ARM hardware float, and the C compilers/assemblers are imported from Plan 9/Inferno. Threads: per-architecture compilers, register allocator/peephole, C compilers, assemblers.

• Per-architecture compilers 6g/8g/5g/9g and the shared gc code generator — Done:
  • 2008: 6g emits amd64 (0cafb9ea3d, d83b994da6, f7753f1687, 36bfd2a906, method/interface code 8231e94520); morestack magic number $a-b produced by 6g and 6c (3f982aeaf6); fat-copy and overlap fixes (30fd44cf9d).
  • 2009: 8g and 5g created and bootstrapped (dc5b4678e2, a8e4ed6a3d, 3aa006b8cd, eac5db7f4c, 63e1b714de, 190b5c9ad2, 4556c04d8b, 86987055a3, 6d0983ae46); nil-pointer checks in 8g (9dd2e1e30f); inline x[lo:] slicing (652f55672d, 9bf597a210, bf0130cc0f); Go types in the object symbol table (43f29e64a6); first attempt at bounds-check elimination for range and [256]array[byte] (fdb030d86f); 8g bounds failures call throwindex (dc30800c28).
  • 2010: complex numbers (426099f42e for 6g, f229c8b546 identical 6g/8g with 5g a stub, b0ad7a4268 5g regalloc for complex); string index inlined in all three (e48c0fb562); amd64 TLS moved to segment memory so R14/R15 return to the register pool (e473f42b2d); ARM hardware float (9c6df3ca13); O(1) string compare when lengths differ (30dd191171); dead code elided (410927d1ad).
  • 2011–Feb 2012: explicit alignments (e7a0f67603), inline append when len<cap (d6b2925923), compact stack frames (2ac375b2df, ARM 2ad42a8249, unified layout 5ddf6255a1), f() < g() order (bac8f18035), goto restrictions (7f4c5ea7d8), interface ==/!= fast-path on differing types (f91cc3bdbb, ~3x for err == io.EOF), correct boundary checks in all compilers (6ed2b6c47d), NOPTRBSS for large pointer-free data (5bcad92f07). Left open: 6g still had 32-bit int; 5g and 8g trailed 6g in code quality.
• Register allocation and the peephole optimizer (reg.c, peep.c) — Done: optimizer and indexing/op= improvements (2dd16a3208, e081f25c3e, a6182dab47, 9a5c7eab16, c8a66a98ff); constant propagation for assignments (567a7bf664); 8g optimizer (0eb2a79ff3, 4ab0ce107a); aliasing fixes (bedfc2c2f1, cd00bc78da); ARM optimizer (90ca4d75a4, 4ed17ceace), disabled for the release (1c99bdc8e5, d88f717da6), peep re-enabled (1f55105f66, 2799e0ecb9, dc331e6565, 63c24081a0); register liveness (84f291b1bd); “registerize variables again” (e419535f2a); loop finding (e2d326b878); flush modified globals aggressively (8998835543); constant propagation friendly to inlining (fff732ea2c); byte-move rewrite in 8g with up to -69.83% on crc32 (23f6479be6). Left open: ARM peephole disabled in releases; optimizer bugs recurring.
• Expression and statement code quality in 6g/8g/5g (division, bounds checks, loops, slices, interfaces) — Done: divide-by-constant (f1baf78247, 34f76b5de5), 8-bit div/mod (3f91f80a21), inline slicearray/sliceslice (9bf597a210, bf0130cc0f), x[lo:] (652f55672d), scaled indexing (c8a66a98ff), 64-bit shift fix (e5bd12ea90), NaN-safe comparisons (109a976355, ef46a9ddac), avoid unneeded conversions in bounds checks (d14baee96e), a[byte(x)] truncation (ba50599e46), bounds checks off support (c332ff42fe), 8g: float->uint64 (a551ffe809, f570d9d765).
• Stack frame layout, prologues, stack split and frame pointers — Done: morestack magic operand (3f982aeaf6), stack-split segment size bug (cb15bbe748), argsize rounding smash on 32-bit (de663b2d6b), 5l morestack for ARM (1ac2cfc720), NOSPLIT checks in cc (36c5c5bf40), frame compaction (2ac375b2df, 2ad42a8249, 5ddf6255a1), .
• Zeroing and copying: Duff’s device, REP, unaligned moves and AVX2 runtime assembly — Done: direction-bit convention (8f53bc0612), fat copy overlap (30fd44cf9d), reverse character copy in sgen (1d0b65d33f).
• The Plan 9 C compilers (cc, 5c/6c/8c) in the Go toolchain — Done: the imports and 8c/5c bring-up above; many 6c/8c code-gen fixes (902a4d5f29 large constants, 5e5476c2fe byte* difference, d4ad8e8ce3 misaligned arguments, 494bcc80e4 extern static registers in 5c, ee7c64efe5 extern register vars only in MOVL, 3e0adc9ffb vlong condition, 5124e66fca), removal of fixed-size buffers (139a053733, 77053797e0, 0e47c75f60), -S line numbers (2cda191aef), 5c do not use R9/R10 (c475c3071a) and gcc/Plan 9 build fixes (b0449c50f7, 5ea4d73b17, 4c6280b0f1, 3f2cc8ba7e, c8c6e1961d), b0449c50f7.
• Assemblers: 5a/6a/8a/9a and the Go cmd/asm — Done: documentation of the assemblers and loaders (b5ab5d4f12), Windows paths (aed2c06dcb), fixed buffers (07d3e0dce4, 0e47c75f60, 77053797e0), delete 8a’s dreg l.s (783c46b197).

Other changes

• Object-file version header user-visible — object files begin with go object $GOOS $GOARCH release.tag version; stale or mismatched objects are diagnosed rather than silently linked (3f61184e1b).
• Address-taken locals moved to heap internal — if the address of a local is taken it is moved to the heap, the first escape handling (391425ae55).
• Goroutine/defer fixes internal — go/defer on interface methods (751d13cbce), go method (7889e03477), defer fix (5cc32a5348).
• Type tables internal — Sigt/Sigi gain room for a type hash for log-time type switches (5136a9e1f7); no debug symbols for internal-only method types: 15% overhead instead of 30% (ce9b379c90).
• Strings as separate symbols internal — 6g emits each string as its own symbol so 6l can discard strings used by dead code, DUPOK for short strings (83cd4ee070).
• Pointer rewrite for -r internal — heap pointer moves rewritten as xchg (8fb60768c3).
• Complex numbers user-visible — type complex implemented in 6g/8g (426099f42e, f229c8b546, 38ad41c317, 8021296179, 6d8b8101ea).
• cgo on 386 internal — cgo working on linux/386 (e67a5084b8); dynamic-loading FFI attempt (8c253bcae5, 165a99038f).
• Line numbers internal — plan9 line tables (efec14bc5a), precise statement line numbers in all assemblers (2ad521c19a), better ATEXT numbers (1678dcc378).
• 8g 387 stack, float internal — 387 stack bug (e1c347ca59), FCHS for float negation (9686ab2da9), float compare ullman (fb5506600f).
• Build hygiene internal — gcc -Werror (1d26908d3f), many Plan 9 build fixes by Lucio De Re (see C compilers thread), checked-in y.tab.[ch] (0f78ee574b), bison flags (3053778965).
• Index checking and bounds-check elimination internal — drop checks in range over array and [256]array[byte] (fdb030d86f), c332ff42fe; wide index fix on amd64 (155ec1d904, c18db5aa18).
• sigfpe-free constants internal — large immediates avoided (c00f9f49bb), 64-bit shifts (e5bd12ea90).
• ARM internal — software floating point (69188ad9bb), unsigned conversion (41b5fb4761), bugfixes (fa4da33315, 8d76a15122, 0aa2317096, be443ee8bc, a2d2341e80), TST (2a74009675, a093f3d5a0), SP adjust bugs (fa9befd777, 7963b04a18), many arm register bugs (2c35e548bb, 3965519ae5, 3537b79329, eead5e8879).
• Remaining small code-generation, optimizer and tooling fixes (286 commits) internal — per-operator and per-back-end bug fixes and cleanups that do not carry design of their own: division/modulo and byte arithmetic, shifts, ullman ordering, string/slice/interface/complex code, register-allocation and out-of-registers cases, float conversions, array/slice indexing (6633be6a86, 8527f49e24, 498ed50061, d1493d1edc, 6b8bd3556a, a93099cd8c, 181ad4743c, 610644a1ca, b6eca3534c, 36f21e00f5, 2694a85a52, 24dbd2413b, ef61a4cb1e, 3f2d542817, c5bb50c9dc, 1926fef175, 78c8dec944, 87dae02a63, 7d11924c13, 10296166a5, 75937c2a16, 390d5fe5b2, ca029d34b6, dc1602ca23, d3237f9a2a, caa7193c95, 1d31a25d83, c6e8e1cebf, e9a194382e, 41861ca7bb, 851100683e, 907f38acfc, b89c538473, 2679eefb31, c6130e9f1f, 53010efe01, 33ee52727f, a7f1af81bd, 1423bf3dc4, 193eac7917, d40f032d18, 0a7e4a7415, d30c9a4be5, bb3269fba0, 5d5e9f74cb, adaec0c4f4, 8545700af8, 970d6a14c4, d015f896bb, 53a22770a7, 8877d27b40, f25843e65e, b4f8e01acb, 907fea6b54, 4a3ce5f19e, fd922c875d, 74427c6346, d2472eb812, 250ec1665a, ec81145565, dc78c64f23, 79f5697b02, 792145723e, e875055461, 93c8d3c41b, 64718ec262, 8e3fe10ee3, a0a14b98fa, a4459c5520, 937ac13f26, 719b088697, 23fc0ac061, 42d89ac02c, dcc064fe94, c9954c63a8, 6fa74e0973, a91a0a6a7a, 7cfe782a69, 2b33a134a8, 1b1f1b53ea, 1b7881adb4, 35e37bbf41, e90314d024, 743ac07cc3, 282bf8cc8c, 4f49b88dda, 56003374d3, 0c4f4587d7, 48f6b516e2, 0932b1f9b8, 5a68303a15, 99cc2fee81, e5ba266e93, b199035ba8, 6b07021a2b, f9854978e2, 91ce0ef8f3, a5a878986c, 3e9b171b79, 5a67ea3883, 52b0f77bf9, 4238b18344, 798b19bf77, 51bb8795cd, 1c7bee0567, 9a9ffb2b0e, 25ac4d07a2, e9e388412c, 0aef57e37f, b2871b727e, a7735f8a16, 6da41be2d3, cd4aab62e3, 908cd8f857, 7472f4c951, 9e2f2fcd2e, 7258bac6e8, 60d223a418, 30228a3bc6, d6f89c69c4, 2946069e3f, b754b4348f, d169dcee3b, 4dec8ef35a, 76a763e0be, 8b8a2bd945, 07044ba6e5, 812f06b3ca, 60238e25bf, f70e285178, dd5f32330c, b0a0e3c439, e7acb5df07, 382a19c3de, 8e96b45fd6, 8811896597, 8a45917f3d, f50e7b156e, c6fd23ce6d, 89f69bb3be, c19c933f5a, ee31157e16, 47c568880d, 3983171b08, be219c5e9b, 6e8524be18, 9e85c790e5, 18f2e360a0, 2204cfddea, 4c952153aa, ff196fbde7, 803a73c431, 6b0bd43fe4, 2c7ec3d861, 2975308125, 8ce5f6e14a, 5de6096415, 24bfaaf07a, 8ccf8240f4, 187cc1eb49, 399d23d4f4, a1b4796394, 8fd53f4754, 57f834aeff, 3e5a817d07, 11d3805579, 5afce0ca85, 620ec45c5f, 116beb2653, 6084dcdd07, 101f7cbd61, 545dbd810c, 8fffa1d698, dde4090372, 02fd255a14, 03bbfe6724, a9e03ae52a, 942d6590d9, f860bc0f4e, 68d5c51287, 1228112b50, 58ee1f5d54, d00248980b, 3fa379e797, fd7d803535, ae39a1d8ec, b18bee948e, bae4f5085e, 2b1133ff86, 1664e81585, 69c0edd59b, 62be24d949, 7c4aeec868, 3ca1b1d27f, dfc0ed9559, cd47c903e2, 758f2bc556, 7263bfc73b, 424f9ca6ab, 45515011cc, 0b4d8c19af, f59cb49a5a, bc6878331a, 7d4b1e4c0d, ac499ed7a5, 4f89dcdf99, 16e6df9807, 60c2e5f453, 9e0ae94e72, 97d0e8fe6c, f75d0d224f, c66b49845c, b0283611e4, 09b2de77b5, 9fc9246bf3, 6a060200cc, a212d174ac, e5d748a333, 1246ad8390, 7c9ed7946c, b2a919fc29, ece6a8c549, 607eaea456, 14e0df34fd, 1d77ff5b6b, 5b0c317c9c, 57858b70fb, 53fff1e74d, d9c989fa25, 6096fc83cd, 45c48d51f7, d853b594b4, 8d50557979, 1b31c37428, ab4d8bf16c, 1558834248, 50fe459ce2, 5cf120827c, e6a934a1d9, 80f07cfbea, e26b741523, 5080d7617a, acc82ad721, cc4d57abac, 66f09fd459, 4c137b6162, a12d70f60d, beb64bbd6e, 3a1fdc655e, a46a311dec, 2286471651, e59aa8ea4a, 17ca32e9db, fd2e24727e, 5d9dbe19a7, 5a5a7b5163, e852202f37, c945d9c8a1, a84abbe508, f91eb3c2f9, 08bfb39515, 8c23c1ab87, 28a23675cd, 317911c9ff, 61f84a2cdc, 4fb3c4f765, 919cb2ec7c, ad7dea1e96, 092a211fb9, 1bc1caa802, 6bee4e556f, 8c0b699ca4, 61655bc513, a6c49098bc, 5ad9e2db28, f3492a7d40, ca5da31f83, 5340510203, a7b83f2287, 1c987a321f, b40000423b, f2ad374ae6, a5bc16d619, 123130f789, 436f297d1e, 9984a5bca4)
• Build, portability and warning fixes (47 commits) internal — Plan 9/gcc/clang warnings, yacc/bison, format verbs, buffer sizes, output-file handling and Windows paths in the compilers/assemblers/liblink (461d1b7987, 34514bdb72, 76036192b9, b676b0e125, 45f4e38506, b7f01f9f41, 859ba57bbb, 8f5bba0d82, 58b280db3b, 122ed3e988, f61639d4e2, 58f7fc331f, 8720b4721f, 1faf06eabf, 189153ed13, a121410541, ebdbbe0f49, f63b0d6b71, 7a87a3e0df, 40bcbb30b7, d4903abeae, 1a0860b93f, a0a965fbcf, b71c484c91, 8037e3ba5e, 8c3d2f015b, e9ac56fb99, c3343ef62c, 593ccd1d44, e69f12ae1d, 6fc820729e, aafe474ec9, 66905bd9ac, 29cf90a4ef, f1781bec3b, 2d310a0087, 12b2269860, 6bcfb95168, d0ac84fe40, 67edf9cb87, 5e188b40f2, 335da67e00, 6273d6e713, e280035fc1, 7ac03695f8, fec7fa8b9d, dbec42104f)
• Object format and early backend work internal — Updated 8a/8c/8l to the new object format, brought up 8g, renamed dynld to dynimport, and added comments, dead code removal and small cleanups. (2bd101c4b1, f54d73b880, 2d259c817a, d8c7980514, 021abfbd28, 3c06bd6201, 0e2cce70cb, e667e8a4f7)

Linker and object files

From Linker and object files (Go 1.0–1.9)

Everything from the first 6l/8l/5l through Go 1: ELF, Mach-O and PE writers, the shared src/cmd/ld, dead-code elimination, symbol/pclntab as rodata, DWARF, NOSPLIT checking, cgo dynamic imports, and ports to OpenBSD/NetBSD/Windows/NaCl.

• Early loaders 5l/6l/8l and the shared src/cmd/ld (2008–2011) — Done:
  • 2008: ELF header and .shstrtab handling for 6l (6a659ebf13, 2c52881a85, 67e141b637); symbol table and line/pc information in 6.out (e9c9c9ace5), Mach-O debug support (073486c3ed); segmented stacks in 6l (1f6828bcdf, b987f7a757); .gosymtab/.gopclntab as ELF note sections and text starting at 4MB (c3ca056143); archive/__.PKGDEF handling and a pkg search directory (12c81a0ce8); dynamically linked output on darwin (cfb9425460).
  • 2009: 8l generating Mach-O and ELF (7d443bb67a); 5l ELF support (4e1896a1b5, 3c7a1ef208); dead data and code actually eliminated, not just symbols (8d8225d529, 9cba9c8890); elf64 scaffolding (1593b1fc23, e86dcf1603, b63d40a53e) and dynamically-linked 6l output with .interp (3d42e691b9, 304b7954e8); dynamic loading / FFI pragmas feeding cgo (bd4161fcba, 165a99038f, 133a158bd8, 732f3919ab, 9e0ae94e72); FreeBSD touch-ups (60b1a17b9e), -d meaning flipped; hash table for dynamic symbols (dc43b74eb1).
  • 2010: Native Client steps in 8l (4a4ec23870, eae0906bed, 7390aa0102); Windows PE output for 8l (977e19d69f, 3b1a71862e, 30f981d980) and Windows dynexport (a3120f67ca); -s binaries kept valid (000ab98df6); rodata moved into the text segment (698fb4f192, b7e9e9188a); function-at-a-time layout, pclntab/symtab as ordinary rodata (19fd5c787f, below); ELF/Mach-O object reading for cgo (4d8d6d5cda, cf42a45587, f5690004c2); weak symbols (d94bf76239); OpenBSD (ffa14e849c, 26d9c804f8) and netbsd/ELF note (420fe22921, 5842f7e46a) support; 6l moved to PE for windows/amd64 (3aec5516ed).
  • 2011: Plan 9 native-build fixes (9baaa6f742, 10b5519d3a, 5ea4d73b17, 4c6280b0f1); rpath dropped (afac1c2654); Mach-O linkedit rework so codesign works (78ad19f214, 4566868b41, 280d85a80b); alignment of ELF data sections (bf43161c00); -X (e3755434b8); GOROOT_FINAL rewrite of file names (6e3a7930eb); fix of NOSPLIT stack-overflow near segment size (9e5db8c90a). Left open: the pclntab/symtab encoding was still the Plan 9 format with big-endian values (see 1.1); the three linkers still shared only part of their code; no way to link with the host linker.
• Go symbol table, pc/line table and function metadata (gosymtab, pclntab, findfunc) — Done: symbol and line tables added (e9c9c9ace5); stack offset table marker per TEXT (f997bc6eb6, ddba96aed8) later replaced by the in-memory symbol table (3aa063d79c); Go type info in the symbol table (43f29e64a6, 311c0b4807: archive size +70%, binary +30%), later with the gotype pointer carved out (57a9bd0ee3); symbols for type/string/go.string omitted (7a09a88274); pclntab/symtab as ordinary rodata (19fd5c787f); -s elides the Go symbol table (10d0dffd76); ELF symbol table for nm/oprofile (96ea081c04, 70798eaad6); symbol table letter correctness (c2cd0d09c2) and sizes preserved through data layout (f0ab14647a). Left open: encoding fixed to big-endian Plan 9 format.
• Stack splitting and the linker’s nosplit overflow check — Done: the above plus the detection of NOSPLIT overflow (d9fd11443c), a fix for near-segment-size stacks (9e5db8c90a), frame-size-aware morestack on 5l/8l (1fa4173444). Left open: nothing noted.
• Dead code and data elimination — Done: dead data and code elimination (8d8225d529, 9cba9c8890, 7b29dbb866), object-granularity loading replaced by “load everything and flood” (fc8dca9dac, 49084db386); struct field tracking experiment is separate (1.1). Left open: nothing noted.
• DWARF generation in the linker — Done: initial DWARF for 6l/8l on ELF, Mach-O and later PE (ca9098ee94, b433552ebc, 728003e340, f1751e7de5); frame info (eb572e0174); gdb type support (9a71bb00bb, 7a4ce23d65); filenames in the .debug_line header (d164b6081d); Mach-O DWARF before linkedit (4566868b41); relocated DWARF for external objects (below). Left open: ARM had no line info until 1.1.
• Linker speed and memory (Go 1.7 focus) — Done: 1bc84b7e18, 8a6da2f6a0, 9c7535432a, 505fd760a2.
• Runtime type data, GC metadata and sections laid out by the linker — Done: noptr data/bss (4e3f8e915f, 5bcad92f07, 433e47dc03), type symbol machinery (0532f89b1f, 47caf6424c), reflect PtrTo (44fd7573aa).
• Container writers: Windows PE, Mach-O and Plan 9 — Done: PE, Mach-O code signing, dynamic Mach-O and Windows cgo as listed (977e19d69f, 3aec5516ed, 78ad19f214, c9bf048337, 133a158bd8). Left open: Plan 9 output was maintained by community patches (c14c4e55e0, 8221eb9103, c7008f47ec).
• Architecture and OS ports in the linker (arm, power64, arm64, mips, s390x, nacl, BSDs, Solaris) and trampolines — Done: ARM, 386, amd64 ports with the ISA additions listed (e.g. 9c6df3ca13, fc41e621e8, 895631770a); OS ports: OpenBSD, NetBSD, FreeBSD, Windows, NaCl.
• Build IDs, ABI hashes, flags and determinism — Done: GOROOT_FINAL rewrite (6e3a7930eb), -X (e3755434b8), -u safe check (6519a6ba5b, 829896168c).

Other changes

• Instruction-set additions in the loaders internal — 6l/8l/5l grew encodings as the runtime and libraries needed them: SSE/MOVQ (17105870ff, c8a2be8c38, 884dceca1f, 4d429c7fe5), CMOV/FCMOV/FCOMI (baea3e946d, 4af0a58ea9, 5107aa82a1), CMPXCHG8B/XADD (895631770a), EMMS/fences (aaac05ae23, fc444ebac1), RDTSC (6392b43a15), LDREX/STREX (f72ea8eb76; LDREXD/STREXD 96c785de39), SQRT in ARM (fc41e621e8), MOVLQZX as plain mov (bf10982739), JCXZ forms (a88994f804, 26608d4fbb), IMUL3Q/SHLDL (36d3707009), CALL reg encodings, vDSO syscalls on Linux x86 (c20a338c2f).
• Hardware floating point on ARM internal — 9c6df3ca13 added VFP with softfloat still broken at that point; ae60526848 simulation; 8052786e51 stopped using R12 as SB.
• ELF layout fixes internal — PHDR in PT_LOAD (f1df07bf6a, 1c0c252880), DT_DEBUG (a55de2ba61), Xen-friendly ELF TLS sequence on linux/386 (2d6ae385e1), strip-safe sections (000ab98df6, cf143e9dbf, ba2e3af177), read-only .rodata (a84e9d01f0, 15d8b05f0c), versioned ELF symbols for cgo (09092a78e6), static-binary detection when no shared libs (296d6871a8, e69b9ddd42).
• Import cycles and invalid inputs internal — all import cycles detected (b9b204d55d) — rejects invalid input files (e692977af3, 9a442211c6), unsafe import exit code (d4b19bdbed).
• Heap/gc diagnostics and leaks internal — a2ba34d374, 916eea04f8 fix memory leaks; f0e6a3caac dangling pointer found by valgrind.
• Build system internal — 4f8117d9eb bakes GOOS/GOARCH/GOROOT defaults into tools, ccbcefe2b6 ignores $GOARCH in compiler and linker; makefile restructuring (6609d2f88d, 9dd354c63f drops use of ed).
• Early object/loader mechanics (2008–2009) internal — typestring and type-signature machinery that preceded compiler-emitted strings (2c3ddf5ef6, 1983121bbb marks signatures DUPOK so several .6 can contain them, d6a7cefd1e, 8f14451fe5), sys.unreflect-related loader changes, archive handling (c5f21c0dc2 ignores references into the original source directory, bfd5ede78d -P pkgdir, 2f1a321d4f search runtime.a in the package path, 122f3980c7 quoted spaces), diagnosing missing symbols (8559e3ad54, 29e93590b0), JMP/branch handling (e2fa41ab3b, cc4dc5a22a, 4d6bccb0f1, de0d762a0f), runtime location changes (9ff0e6288e, 34a5537edb, b7f0580274), 8l/5l bring-up (af0143ce03, 07393f8706, f2201185ab porting ld/go.c functionality to 5l, 97fe55720d, a2cf914379, fcb9387089, 0c71ead9e6, 8613eb56b2), mach/ELF debugging aids (284a50c109, 67addd4e11, 7fa5941fad, e2c3ec3173, 36f21e00f5), and small linker bug fixes (95100344d3 runtime stack overflow with deferproc+morestack, 8db677b0a7, 10e995fba8, 997b6f9d89, fd6cdbd807 more ELF constants and a simple relocation demo, a0a965fbcf, c64986f706 merging the first span pass into the main loop to halve NaCl changes, 98fff8ffb2, 86cfaf66a7, dfeceddd3f, 45ce825544 debugging symbols for 8g, a1b64821f8, 002623704f, 005509e367, 285b6021e9).
• Stack-split fixes on ARM and amd64 internal — 1ed7f18165, 5963f59067, 0af8e1045c, c2b91d4889, 231fcea7e6, 0af8e1045c, 71c4244430, 29c6c09f71 fix morestack calling conventions and float-instruction branch targets.
• Bring-up of ports and fixes internal — ARM instruction fixes (35a775d045 SWI with long constants, 2a74009675, a093f3d5a0 TST, ca5179d3f6, 888ab02228, 40745a579c pre-ARMv4 removed, e8f2692ca2, 60238e25bf 11 FP registers, b28d84f644, 1fddbab736, 3d0a85785a data-relocatable layout), Windows PE fixes (6e18e8c82f, 77eb94c032, d5dffb9f29, 5e4963d9e8, 8f8f625cb1, 48d2de7eb9, d08df51366, 8ba4df2e9a, 354219951e, 2da651f115, 1ac7a69701, b05679cdd6, ff866c4ca3, 8ed9fc600c, 74a23646bc, e7042418c5, 77a70ddb7b, c2c7ee2736), Mach-O (3d0726b04d, 8a1b2e59ef, cf3323f511, 2aceea630f, 047e698c52, d2b2b3f4a8), ELF (91cf0af181, 14eba969d8, 1116ec4f20, 01464cf956, 8ec6f7cd11, 1b2d5b4c93, 7431a3165e, c5030e5f4b, 89d334ffe1, 2ccbf83b32, 033585d675, 6334b499e8, 44e51fad28, f3ed1ad50c), Plan 9 (4fca395321, 45407bd559, 340251e43d, 36b6d1aaf2, f367c13c79), DWARF (fbd92dba96, f08baa38f8, cc9e6b5cdb, a647f59c1f, da42312268, 0cc055e8f7, c7c16175e0, ac1b9545e3, 054be1b6c3, b99d722963) and 3554325937, caa5647408, be2c2120d0, 54aba2e6dd, 92c6061b5c, 423ab2333a, 1a472026da, 837c204ada, dd93df35b9, 507df959e4.
• Housekeeping and build hygiene internal — gcc/Plan 9 warning cleanups and documentation (326bb67fbf, 6fff0efdd8, 354e61cc52, d6197d94b5, e1325d916e, 2a1c9377d9, b5ab5d4f12, 3fa379e797, 18cb960f3e, 6634e3432d, 26b55e44d9, f2c7a20142, b73b43ea31, 3884f7321f, d64a2bddf0, 63623ba2d8, 05cc83bf4e, 1f6f563900, d42903119b, d9c989fa25, 88cf5564fc, f8b7eda5f6, 0cd3475386, eaa082f691, 12b2269860, 3e57d7f7bf, b88e669a8f, 648f25b237, 29cf90a4ef, a89c0ff39e, 07dc26f88d, f1781bec3b, 11e07d23ed, d26e73646e, 839abc2ea7, 1063ed8f3b, 33405ecc86, f0bde7c51b, 1964417e41, c6138efbcb, 4304de6e0c, 0490eb60bb, 8c5c3c504c, 93ecb5bb1b, f12e543255, 05f734c8b4, f554c90cef, 2cf5359830, 11fe7cd6e3, b24d1cb5ec, 2d64bab1de, 9af4b01654, 916f896a3b, 40ff071e9b, f8e9bbe475, 5aea33742a, 489494cac3, 44eaaaaa78, bd43a2d9ff, 7b04471dfa, eae0a48cf5, 9f4c288c16 hash/crc32 SSE4.2, 1ed7f18165, 99cc2fee81, 94d89ede1c).
• Early linker cleanups internal — Cleaned up exec header generation, ELF64 magic numbers, 5l/6l/8l, and removed D_SBIG. (fe734d8630, f687fb7e73, 335b3855c6, 0e25c1dc6d, 085be1740a, 8132f1d016, 14b9032f84)
• FFI relocations internal — Used //ffi comments in import data to generate relocations and library loads. (1f177cd8b2)