libgo/runtime/runtime.h

   1 // Copyright 2009 The Go Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style
   3 // license that can be found in the LICENSE file.
   4
   5 #include "config.h"
   6
   7 #include "go-assert.h"
   8 #include <complex.h>
   9 #include <signal.h>
  10 #include <stdio.h>
  11 #include <stdlib.h>
  12 #include <string.h>
  13 #include <sys/types.h>
  14 #include <sys/stat.h>
  15 #include <fcntl.h>
  16 #include <unistd.h>
  17 #include <pthread.h>
  18 #include <semaphore.h>
  19 #include <ucontext.h>
  20
  21 #ifdef HAVE_SYS_MMAN_H
  22 #include <sys/mman.h>
  23 #endif
  24
  25 #include "interface.h"
  26 #include "go-alloc.h"
  27
  28 #define _STRINGIFY2_(x) #x
  29 #define _STRINGIFY_(x) _STRINGIFY2_(x)
  30 #define GOSYM_PREFIX _STRINGIFY_(__USER_LABEL_PREFIX__)
  31
  32 /* This file supports C files copied from the 6g runtime library.
  33    This is a version of the 6g runtime.h rewritten for gccgo's version
  34    of the code.  */
  35
  36 typedef signed int   int8    __attribute__ ((mode (QI)));
  37 typedef unsigned int uint8   __attribute__ ((mode (QI)));
  38 typedef signed int   int16   __attribute__ ((mode (HI)));
  39 typedef unsigned int uint16  __attribute__ ((mode (HI)));
  40 typedef signed int   int32   __attribute__ ((mode (SI)));
  41 typedef unsigned int uint32  __attribute__ ((mode (SI)));
  42 typedef signed int   int64   __attribute__ ((mode (DI)));
  43 typedef unsigned int uint64  __attribute__ ((mode (DI)));
  44 typedef float        float32 __attribute__ ((mode (SF)));
  45 typedef double       float64 __attribute__ ((mode (DF)));
  46 typedef signed int   intptr __attribute__ ((mode (pointer)));
  47 typedef unsigned int uintptr __attribute__ ((mode (pointer)));
  48
  49 typedef intptr          intgo; // Go's int
  50 typedef uintptr         uintgo; // Go's uint
  51
  52 typedef uintptr         uintreg;
  53
  54 /* Defined types.  */
  55
  56 typedef uint8                   bool;
  57 typedef uint8                   byte;
  58 typedef struct  Func            Func;
  59 typedef struct  G               G;
  60 typedef struct  Lock            Lock;
  61 typedef struct  M               M;
  62 typedef struct  P               P;
  63 typedef struct  Note            Note;
  64 typedef struct  String          String;
  65 typedef struct  FuncVal         FuncVal;
  66 typedef struct  SigTab          SigTab;
  67 typedef struct  MCache          MCache;
  68 typedef struct  FixAlloc        FixAlloc;
  69 typedef struct  Hchan           Hchan;
  70 typedef struct  Timers          Timers;
  71 typedef struct  Timer           Timer;
  72 typedef struct  GCStats         GCStats;
  73 typedef struct  LFNode          LFNode;
  74 typedef struct  ParFor          ParFor;
  75 typedef struct  ParForThread    ParForThread;
  76 typedef struct  CgoMal          CgoMal;
  77 typedef struct  PollDesc        PollDesc;
  78 typedef struct  DebugVars       DebugVars;
  79
  80 typedef struct  __go_open_array         Slice;
  81 typedef struct  __go_interface          Iface;
  82 typedef struct  __go_empty_interface    Eface;
  83 typedef struct  __go_type_descriptor    Type;
  84 typedef struct  __go_defer_stack        Defer;
  85 typedef struct  __go_panic_stack        Panic;
  86
  87 typedef struct  __go_ptr_type           PtrType;
  88 typedef struct  __go_func_type          FuncType;
  89 typedef struct  __go_interface_type     InterfaceType;
  90 typedef struct  __go_map_type           MapType;
  91 typedef struct  __go_channel_type       ChanType;
  92
  93 typedef struct  Traceback       Traceback;
  94
  95 typedef struct  Location        Location;
  96
  97 /*
  98  * Per-CPU declaration.
  99  */
 100 extern M*       runtime_m(void);
 101 extern G*       runtime_g(void);
 102
 103 extern M        runtime_m0;
 104 extern G        runtime_g0;
 105
 106 /*
 107  * defined constants
 108  */
 109 enum
 110 {
 111         // G status
 112         //
 113         // If you add to this list, add to the list
 114         // of "okay during garbage collection" status
 115         // in mgc0.c too.
 116         Gidle,
 117         Grunnable,
 118         Grunning,
 119         Gsyscall,
 120         Gwaiting,
 121         Gmoribund_unused,  // currently unused, but hardcoded in gdb scripts
 122         Gdead,
 123 };
 124 enum
 125 {
 126         // P status
 127         Pidle,
 128         Prunning,
 129         Psyscall,
 130         Pgcstop,
 131         Pdead,
 132 };
 133 enum
 134 {
 135         true    = 1,
 136         false   = 0,
 137 };
 138 enum
 139 {
 140         PtrSize = sizeof(void*),
 141 };
 142 enum
 143 {
 144         // Per-M stack segment cache size.
 145         StackCacheSize = 32,
 146         // Global <-> per-M stack segment cache transfer batch size.
 147         StackCacheBatch = 16,
 148 };
 149 /*
 150  * structures
 151  */
 152 struct  Lock
 153 {
 154         // Futex-based impl treats it as uint32 key,
 155         // while sema-based impl as M* waitm.
 156         // Used to be a union, but unions break precise GC.
 157         uintptr key;
 158 };
 159 struct  Note
 160 {
 161         // Futex-based impl treats it as uint32 key,
 162         // while sema-based impl as M* waitm.
 163         // Used to be a union, but unions break precise GC.
 164         uintptr key;
 165 };
 166 struct String
 167 {
 168         const byte*     str;
 169         intgo           len;
 170 };
 171 struct FuncVal
 172 {
 173         void    (*fn)(void);
 174         // variable-size, fn-specific data here
 175 };
 176 struct  GCStats
 177 {
 178         // the struct must consist of only uint64's,
 179         // because it is casted to uint64[].
 180         uint64  nhandoff;
 181         uint64  nhandoffcnt;
 182         uint64  nprocyield;
 183         uint64  nosyield;
 184         uint64  nsleep;
 185 };
 186
 187 // A location in the program, used for backtraces.
 188 struct  Location
 189 {
 190         uintptr pc;
 191         String  filename;
 192         String  function;
 193         intgo   lineno;
 194 };
 195
 196 struct  G
 197 {
 198         void*   closure;        // Closure value.
 199         Defer*  defer;
 200         Panic*  panic;
 201         void*   exception;      // current exception being thrown
 202         bool    is_foreign;     // whether current exception from other language
 203         void    *gcstack;       // if status==Gsyscall, gcstack = stackbase to use during gc
 204         uintptr gcstack_size;
 205         void*   gcnext_segment;
 206         void*   gcnext_sp;
 207         void*   gcinitial_sp;
 208         ucontext_t gcregs;
 209         byte*   entry;          // initial function
 210         void*   param;          // passed parameter on wakeup
 211         bool    fromgogo;       // reached from gogo
 212         int16   status;
 213         uint32  selgen;         // valid sudog pointer
 214         int64   goid;
 215         int64   waitsince;      // approx time when the G become blocked
 216         const char*     waitreason;     // if status==Gwaiting
 217         G*      schedlink;
 218         bool    ispanic;
 219         bool    issystem;       // do not output in stack dump
 220         bool    isbackground;   // ignore in deadlock detector
 221         bool    paniconfault;   // panic (instead of crash) on unexpected fault address
 222         M*      m;              // for debuggers, but offset not hard-coded
 223         M*      lockedm;
 224         int32   sig;
 225         int32   writenbuf;
 226         byte*   writebuf;
 227         uintptr sigcode0;
 228         uintptr sigcode1;
 229         // uintptr      sigpc;
 230         uintptr gopc;   // pc of go statement that created this goroutine
 231
 232         int32   ncgo;
 233         CgoMal* cgomal;
 234
 235         Traceback* traceback;
 236
 237         ucontext_t      context;
 238         void*           stack_context[10];
 239 };
 240
 241 struct  M
 242 {
 243         G*      g0;             // goroutine with scheduling stack
 244         G*      gsignal;        // signal-handling G
 245         byte*   gsignalstack;
 246         size_t  gsignalstacksize;
 247         void    (*mstartfn)(void);
 248         G*      curg;           // current running goroutine
 249         G*      caughtsig;      // goroutine running during fatal signal
 250         P*      p;              // attached P for executing Go code (nil if not executing Go code)
 251         P*      nextp;
 252         int32   id;
 253         int32   mallocing;
 254         int32   throwing;
 255         int32   gcing;
 256         int32   locks;
 257         int32   softfloat;
 258         int32   dying;
 259         int32   profilehz;
 260         int32   helpgc;
 261         bool    spinning;       // M is out of work and is actively looking for work
 262         bool    blocked;        // M is blocked on a Note
 263         uint32  fastrand;
 264         uint64  ncgocall;       // number of cgo calls in total
 265         int32   ncgo;           // number of cgo calls currently in progress
 266         CgoMal* cgomal;
 267         Note    park;
 268         M*      alllink;        // on allm
 269         M*      schedlink;
 270         MCache  *mcache;
 271         G*      lockedg;
 272         Location createstack[32];       // Stack that created this thread.
 273         uint32  locked; // tracking for LockOSThread
 274         M*      nextwaitm;      // next M waiting for lock
 275         uintptr waitsema;       // semaphore for parking on locks
 276         uint32  waitsemacount;
 277         uint32  waitsemalock;
 278         GCStats gcstats;
 279         bool    needextram;
 280         bool    dropextram;     // for gccgo: drop after call is done.
 281         uint8   traceback;
 282         bool    (*waitunlockf)(G*, void*);
 283         void*   waitlock;
 284         uintptr end[];
 285 };
 286
 287 struct P
 288 {
 289         Lock;
 290
 291         int32   id;
 292         uint32  status;         // one of Pidle/Prunning/...
 293         P*      link;
 294         uint32  schedtick;      // incremented on every scheduler call
 295         uint32  syscalltick;    // incremented on every system call
 296         M*      m;              // back-link to associated M (nil if idle)
 297         MCache* mcache;
 298         Defer*  deferpool;      // pool of available Defer structs (see panic.c)
 299
 300         // Cache of goroutine ids, amortizes accesses to runtime_sched.goidgen.
 301         uint64  goidcache;
 302         uint64  goidcacheend;
 303
 304         // Queue of runnable goroutines.
 305         uint32  runqhead;
 306         uint32  runqtail;
 307         G*      runq[256];
 308
 309         // Available G's (status == Gdead)
 310         G*      gfree;
 311         int32   gfreecnt;
 312
 313         byte    pad[64];
 314 };
 315
 316 // The m->locked word holds two pieces of state counting active calls to LockOSThread/lockOSThread.
 317 // The low bit (LockExternal) is a boolean reporting whether any LockOSThread call is active.
 318 // External locks are not recursive; a second lock is silently ignored.
 319 // The upper bits of m->lockedcount record the nesting depth of calls to lockOSThread
 320 // (counting up by LockInternal), popped by unlockOSThread (counting down by LockInternal).
 321 // Internal locks can be recursive. For instance, a lock for cgo can occur while the main
 322 // goroutine is holding the lock during the initialization phase.
 323 enum
 324 {
 325         LockExternal = 1,
 326         LockInternal = 2,
 327 };
 328
 329 struct  SigTab
 330 {
 331         int32   sig;
 332         int32   flags;
 333 };
 334 enum
 335 {
 336         SigNotify = 1<<0,       // let signal.Notify have signal, even if from kernel
 337         SigKill = 1<<1,         // if signal.Notify doesn't take it, exit quietly
 338         SigThrow = 1<<2,        // if signal.Notify doesn't take it, exit loudly
 339         SigPanic = 1<<3,        // if the signal is from the kernel, panic
 340         SigDefault = 1<<4,      // if the signal isn't explicitly requested, don't monitor it
 341         SigHandling = 1<<5,     // our signal handler is registered
 342         SigIgnored = 1<<6,      // the signal was ignored before we registered for it
 343         SigGoExit = 1<<7,       // cause all runtime procs to exit (only used on Plan 9).
 344 };
 345
 346 // Layout of in-memory per-function information prepared by linker
 347 // See http://golang.org/s/go12symtab.
 348 // Keep in sync with linker and with ../../libmach/sym.c
 349 // and with package debug/gosym.
 350 struct  Func
 351 {
 352         String  name;
 353         uintptr entry;  // entry pc
 354 };
 355
 356 #ifdef GOOS_nacl
 357 enum {
 358    NaCl = 1,
 359 };
 360 #else
 361 enum {
 362    NaCl = 0,
 363 };
 364 #endif
 365
 366 #ifdef GOOS_windows
 367 enum {
 368    Windows = 1
 369 };
 370 #else
 371 enum {
 372    Windows = 0
 373 };
 374 #endif
 375 #ifdef GOOS_solaris
 376 enum {
 377    Solaris = 1
 378 };
 379 #else
 380 enum {
 381    Solaris = 0
 382 };
 383 #endif
 384
 385 struct  Timers
 386 {
 387         Lock;
 388         G       *timerproc;
 389         bool            sleeping;
 390         bool            rescheduling;
 391         Note    waitnote;
 392         Timer   **t;
 393         int32   len;
 394         int32   cap;
 395 };
 396
 397 // Package time knows the layout of this structure.
 398 // If this struct changes, adjust ../time/sleep.go:/runtimeTimer.
 399 // For GOOS=nacl, package syscall knows the layout of this structure.
 400 // If this struct changes, adjust ../syscall/net_nacl.go:/runtimeTimer.
 401 struct  Timer
 402 {
 403         int32   i;      // heap index
 404
 405         // Timer wakes up at when, and then at when+period, ... (period > 0 only)
 406         // each time calling f(now, arg) in the timer goroutine, so f must be
 407         // a well-behaved function and not block.
 408         int64   when;
 409         int64   period;
 410         FuncVal *fv;
 411         Eface   arg;
 412 };
 413
 414 // Lock-free stack node.
 415 struct LFNode
 416 {
 417         LFNode  *next;
 418         uintptr pushcnt;
 419 };
 420
 421 // Parallel for descriptor.
 422 struct ParFor
 423 {
 424         void (*body)(ParFor*, uint32);  // executed for each element
 425         uint32 done;                    // number of idle threads
 426         uint32 nthr;                    // total number of threads
 427         uint32 nthrmax;                 // maximum number of threads
 428         uint32 thrseq;                  // thread id sequencer
 429         uint32 cnt;                     // iteration space [0, cnt)
 430         void *ctx;                      // arbitrary user context
 431         bool wait;                      // if true, wait while all threads finish processing,
 432                                         // otherwise parfor may return while other threads are still working
 433         ParForThread *thr;              // array of thread descriptors
 434         uint32 pad;                     // to align ParForThread.pos for 64-bit atomic operations
 435         // stats
 436         uint64 nsteal;
 437         uint64 nstealcnt;
 438         uint64 nprocyield;
 439         uint64 nosyield;
 440         uint64 nsleep;
 441 };
 442
 443 // Track memory allocated by code not written in Go during a cgo call,
 444 // so that the garbage collector can see them.
 445 struct CgoMal
 446 {
 447         CgoMal  *next;
 448         void    *alloc;
 449 };
 450
 451 // Holds variables parsed from GODEBUG env var.
 452 struct DebugVars
 453 {
 454         int32   allocfreetrace;
 455         int32   efence;
 456         int32   gctrace;
 457         int32   gcdead;
 458         int32   scheddetail;
 459         int32   schedtrace;
 460 };
 461
 462 extern bool runtime_precisestack;
 463 extern bool runtime_copystack;
 464
 465 /*
 466  * defined macros
 467  *    you need super-gopher-guru privilege
 468  *    to add this list.
 469  */
 470 #define nelem(x)        (sizeof(x)/sizeof((x)[0]))
 471 #define nil             ((void*)0)
 472 #define USED(v)         ((void) v)
 473 #define ROUND(x, n)     (((x)+(n)-1)&~(uintptr)((n)-1)) /* all-caps to mark as macro: it evaluates n twice */
 474
 475 byte*   runtime_startup_random_data;
 476 uint32  runtime_startup_random_data_len;
 477 void    runtime_get_random_data(byte**, int32*);
 478
 479 enum {
 480         // hashinit wants this many random bytes
 481         HashRandomBytes = 32
 482 };
 483 void    runtime_hashinit(void);
 484
 485 void    runtime_traceback(void);
 486 void    runtime_tracebackothers(G*);
 487 enum
 488 {
 489         // The maximum number of frames we print for a traceback
 490         TracebackMaxFrames = 100,
 491 };
 492
 493 /*
 494  * external data
 495  */
 496 extern  uintptr runtime_zerobase;
 497 extern  G**     runtime_allg;
 498 extern  uintptr runtime_allglen;
 499 extern  G*      runtime_lastg;
 500 extern  M*      runtime_allm;
 501 extern  P**     runtime_allp;
 502 extern  int32   runtime_gomaxprocs;
 503 extern  uint32  runtime_needextram;
 504 extern  uint32  runtime_panicking;
 505 extern  int8*   runtime_goos;
 506 extern  int32   runtime_ncpu;
 507 extern  void    (*runtime_sysargs)(int32, uint8**);
 508 extern  uint32  runtime_Hchansize;
 509 extern  DebugVars       runtime_debug;
 510 extern  uintptr runtime_maxstacksize;
 511
 512 /*
 513  * common functions and data
 514  */
 515 #define runtime_strcmp(s1, s2) __builtin_strcmp((s1), (s2))
 516 #define runtime_strncmp(s1, s2, n) __builtin_strncmp((s1), (s2), (n))
 517 #define runtime_strstr(s1, s2) __builtin_strstr((s1), (s2))
 518 intgo   runtime_findnull(const byte*);
 519 intgo   runtime_findnullw(const uint16*);
 520 void    runtime_dump(byte*, int32);
 521
 522 void    runtime_gogo(G*);
 523 struct __go_func_type;
 524 void    runtime_args(int32, byte**);
 525 void    runtime_osinit();
 526 void    runtime_goargs(void);
 527 void    runtime_goenvs(void);
 528 void    runtime_goenvs_unix(void);
 529 void    runtime_throw(const char*) __attribute__ ((noreturn));
 530 void    runtime_panicstring(const char*) __attribute__ ((noreturn));
 531 bool    runtime_canpanic(G*);
 532 void    runtime_prints(const char*);
 533 void    runtime_printf(const char*, ...);
 534 int32   runtime_snprintf(byte*, int32, const char*, ...);
 535 #define runtime_mcmp(a, b, s) __builtin_memcmp((a), (b), (s))
 536 #define runtime_memmove(a, b, s) __builtin_memmove((a), (b), (s))
 537 void*   runtime_mal(uintptr);
 538 String  runtime_gostring(const byte*);
 539 String  runtime_gostringnocopy(const byte*);
 540 void    runtime_schedinit(void);
 541 void    runtime_initsig(void);
 542 void    runtime_sigenable(uint32 sig);
 543 void    runtime_sigdisable(uint32 sig);
 544 int32   runtime_gotraceback(bool *crash);
 545 void    runtime_goroutineheader(G*);
 546 void    runtime_printtrace(Location*, int32, bool);
 547 #define runtime_open(p, f, m) open((p), (f), (m))
 548 #define runtime_read(d, v, n) read((d), (v), (n))
 549 #define runtime_write(d, v, n) write((d), (v), (n))
 550 #define runtime_close(d) close(d)
 551 void    runtime_ready(G*);
 552 const byte*     runtime_getenv(const char*);
 553 int32   runtime_atoi(const byte*);
 554 void*   runtime_mstart(void*);
 555 G*      runtime_malg(int32, byte**, size_t*);
 556 void    runtime_mpreinit(M*);
 557 void    runtime_minit(void);
 558 void    runtime_unminit(void);
 559 void    runtime_needm(void);
 560 void    runtime_dropm(void);
 561 void    runtime_signalstack(byte*, int32);
 562 MCache* runtime_allocmcache(void);
 563 void    runtime_freemcache(MCache*);
 564 void    runtime_mallocinit(void);
 565 void    runtime_mprofinit(void);
 566 #define runtime_malloc(s) __go_alloc(s)
 567 #define runtime_free(p) __go_free(p)
 568 #define runtime_getcallersp(p) __builtin_frame_address(1)
 569 int32   runtime_mcount(void);
 570 int32   runtime_gcount(void);
 571 void    runtime_mcall(void(*)(G*));
 572 uint32  runtime_fastrand1(void);
 573 int32   runtime_timediv(int64, int32, int32*);
 574 int32   runtime_round2(int32 x); // round x up to a power of 2.
 575
 576 // atomic operations
 577 #define runtime_cas(pval, old, new) __sync_bool_compare_and_swap (pval, old, new)
 578 #define runtime_cas64(pval, old, new) __sync_bool_compare_and_swap (pval, old, new)
 579 #define runtime_casp(pval, old, new) __sync_bool_compare_and_swap (pval, old, new)
 580 // Don't confuse with XADD x86 instruction,
 581 // this one is actually 'addx', that is, add-and-fetch.
 582 #define runtime_xadd(p, v) __sync_add_and_fetch (p, v)
 583 #define runtime_xadd64(p, v) __sync_add_and_fetch (p, v)
 584 #define runtime_xchg(p, v) __atomic_exchange_n (p, v, __ATOMIC_SEQ_CST)
 585 #define runtime_xchg64(p, v) __atomic_exchange_n (p, v, __ATOMIC_SEQ_CST)
 586 #define runtime_xchgp(p, v) __atomic_exchange_n (p, v, __ATOMIC_SEQ_CST)
 587 #define runtime_atomicload(p) __atomic_load_n (p, __ATOMIC_SEQ_CST)
 588 #define runtime_atomicstore(p, v) __atomic_store_n (p, v, __ATOMIC_SEQ_CST)
 589 #define runtime_atomicstore64(p, v) __atomic_store_n (p, v, __ATOMIC_SEQ_CST)
 590 #define runtime_atomicload64(p) __atomic_load_n (p, __ATOMIC_SEQ_CST)
 591 #define runtime_atomicloadp(p) __atomic_load_n (p, __ATOMIC_SEQ_CST)
 592 #define runtime_atomicstorep(p, v) __atomic_store_n (p, v, __ATOMIC_SEQ_CST)
 593
 594 void runtime_setmg(M*, G*);
 595 void runtime_newextram(void);
 596 #define runtime_exit(s) exit(s)
 597 #define runtime_breakpoint() __builtin_trap()
 598 void    runtime_gosched(void);
 599 void    runtime_gosched0(G*);
 600 void    runtime_schedtrace(bool);
 601 void    runtime_park(bool(*)(G*, void*), void*, const char*);
 602 void    runtime_parkunlock(Lock*, const char*);
 603 void    runtime_tsleep(int64, const char*);
 604 M*      runtime_newm(void);
 605 void    runtime_goexit(void);
 606 void    runtime_entersyscall(void) __asm__ (GOSYM_PREFIX "syscall.Entersyscall");
 607 void    runtime_entersyscallblock(void);
 608 void    runtime_exitsyscall(void) __asm__ (GOSYM_PREFIX "syscall.Exitsyscall");
 609 G*      __go_go(void (*pfn)(void*), void*);
 610 void    siginit(void);
 611 bool    __go_sigsend(int32 sig);
 612 int32   runtime_callers(int32, Location*, int32, bool keep_callers);
 613 int64   runtime_nanotime(void); // monotonic time
 614 int64   runtime_unixnanotime(void); // real time, can skip
 615 void    runtime_dopanic(int32) __attribute__ ((noreturn));
 616 void    runtime_startpanic(void);
 617 void    runtime_freezetheworld(void);
 618 void    runtime_unwindstack(G*, byte*);
 619 void    runtime_sigprof();
 620 void    runtime_resetcpuprofiler(int32);
 621 void    runtime_setcpuprofilerate(void(*)(uintptr*, int32), int32);
 622 void    runtime_usleep(uint32);
 623 int64   runtime_cputicks(void);
 624 int64   runtime_tickspersecond(void);
 625 void    runtime_blockevent(int64, int32);
 626 extern int64 runtime_blockprofilerate;
 627 void    runtime_addtimer(Timer*);
 628 bool    runtime_deltimer(Timer*);
 629 G*      runtime_netpoll(bool);
 630 void    runtime_netpollinit(void);
 631 int32   runtime_netpollopen(uintptr, PollDesc*);
 632 int32   runtime_netpollclose(uintptr);
 633 void    runtime_netpollready(G**, PollDesc*, int32);
 634 uintptr runtime_netpollfd(PollDesc*);
 635 void    runtime_netpollarm(PollDesc*, int32);
 636 void**  runtime_netpolluser(PollDesc*);
 637 bool    runtime_netpollclosing(PollDesc*);
 638 void    runtime_netpolllock(PollDesc*);
 639 void    runtime_netpollunlock(PollDesc*);
 640 void    runtime_crash(void);
 641 void    runtime_parsedebugvars(void);
 642 void    _rt0_go(void);
 643 void*   runtime_funcdata(Func*, int32);
 644 int32   runtime_setmaxthreads(int32);
 645 G*      runtime_timejump(void);
 646 void    runtime_iterate_finq(void (*callback)(FuncVal*, void*, const FuncType*, const PtrType*));
 647
 648 void    runtime_stoptheworld(void);
 649 void    runtime_starttheworld(void);
 650 extern uint32 runtime_worldsema;
 651
 652 /*
 653  * mutual exclusion locks.  in the uncontended case,
 654  * as fast as spin locks (just a few user-level instructions),
 655  * but on the contention path they sleep in the kernel.
 656  * a zeroed Lock is unlocked (no need to initialize each lock).
 657  */
 658 void    runtime_lock(Lock*);
 659 void    runtime_unlock(Lock*);
 660
 661 /*
 662  * sleep and wakeup on one-time events.
 663  * before any calls to notesleep or notewakeup,
 664  * must call noteclear to initialize the Note.
 665  * then, exactly one thread can call notesleep
 666  * and exactly one thread can call notewakeup (once).
 667  * once notewakeup has been called, the notesleep
 668  * will return.  future notesleep will return immediately.
 669  * subsequent noteclear must be called only after
 670  * previous notesleep has returned, e.g. it's disallowed
 671  * to call noteclear straight after notewakeup.
 672  *
 673  * notetsleep is like notesleep but wakes up after
 674  * a given number of nanoseconds even if the event
 675  * has not yet happened.  if a goroutine uses notetsleep to
 676  * wake up early, it must wait to call noteclear until it
 677  * can be sure that no other goroutine is calling
 678  * notewakeup.
 679  *
 680  * notesleep/notetsleep are generally called on g0,
 681  * notetsleepg is similar to notetsleep but is called on user g.
 682  */
 683 void    runtime_noteclear(Note*);
 684 void    runtime_notesleep(Note*);
 685 void    runtime_notewakeup(Note*);
 686 bool    runtime_notetsleep(Note*, int64);  // false - timeout
 687 bool    runtime_notetsleepg(Note*, int64);  // false - timeout
 688
 689 /*
 690  * low-level synchronization for implementing the above
 691  */
 692 uintptr runtime_semacreate(void);
 693 int32   runtime_semasleep(int64);
 694 void    runtime_semawakeup(M*);
 695 // or
 696 void    runtime_futexsleep(uint32*, uint32, int64);
 697 void    runtime_futexwakeup(uint32*, uint32);
 698
 699 /*
 700  * Lock-free stack.
 701  * Initialize uint64 head to 0, compare with 0 to test for emptiness.
 702  * The stack does not keep pointers to nodes,
 703  * so they can be garbage collected if there are no other pointers to nodes.
 704  */
 705 void    runtime_lfstackpush(uint64 *head, LFNode *node)
 706   __asm__ (GOSYM_PREFIX "runtime.lfstackpush");
 707 LFNode* runtime_lfstackpop(uint64 *head);
 708
 709 /*
 710  * Parallel for over [0, n).
 711  * body() is executed for each iteration.
 712  * nthr - total number of worker threads.
 713  * ctx - arbitrary user context.
 714  * if wait=true, threads return from parfor() when all work is done;
 715  * otherwise, threads can return while other threads are still finishing processing.
 716  */
 717 ParFor* runtime_parforalloc(uint32 nthrmax);
 718 void    runtime_parforsetup(ParFor *desc, uint32 nthr, uint32 n, void *ctx, bool wait, void (*body)(ParFor*, uint32));
 719 void    runtime_parfordo(ParFor *desc);
 720 void    runtime_parforiters(ParFor*, uintptr, uintptr*, uintptr*);
 721
 722 /*
 723  * low level C-called
 724  */
 725 #define runtime_mmap mmap
 726 #define runtime_munmap munmap
 727 #define runtime_madvise madvise
 728 #define runtime_memclr(buf, size) __builtin_memset((buf), 0, (size))
 729 #define runtime_getcallerpc(p) __builtin_return_address(0)
 730
 731 #ifdef __rtems__
 732 void __wrap_rtems_task_variable_add(void **);
 733 #endif
 734
 735 /*
 736  * Names generated by gccgo.
 737  */
 738 #define runtime_printbool       __go_print_bool
 739 #define runtime_printfloat      __go_print_double
 740 #define runtime_printint        __go_print_int64
 741 #define runtime_printiface      __go_print_interface
 742 #define runtime_printeface      __go_print_empty_interface
 743 #define runtime_printstring     __go_print_string
 744 #define runtime_printpointer    __go_print_pointer
 745 #define runtime_printuint       __go_print_uint64
 746 #define runtime_printslice      __go_print_slice
 747 #define runtime_printcomplex    __go_print_complex
 748
 749 /*
 750  * runtime go-called
 751  */
 752 void    runtime_printbool(_Bool);
 753 void    runtime_printbyte(int8);
 754 void    runtime_printfloat(double);
 755 void    runtime_printint(int64);
 756 void    runtime_printiface(Iface);
 757 void    runtime_printeface(Eface);
 758 void    runtime_printstring(String);
 759 void    runtime_printpc(void*);
 760 void    runtime_printpointer(void*);
 761 void    runtime_printuint(uint64);
 762 void    runtime_printhex(uint64);
 763 void    runtime_printslice(Slice);
 764 void    runtime_printcomplex(complex double);
 765 void reflect_call(const struct __go_func_type *, FuncVal *, _Bool, _Bool,
 766                   void **, void **)
 767   __asm__ (GOSYM_PREFIX "reflect.call");
 768 #define runtime_panic __go_panic
 769
 770 /*
 771  * runtime c-called (but written in Go)
 772  */
 773 void    runtime_printany(Eface)
 774      __asm__ (GOSYM_PREFIX "runtime.Printany");
 775 void    runtime_newTypeAssertionError(const String*, const String*, const String*, const String*, Eface*)
 776      __asm__ (GOSYM_PREFIX "runtime.NewTypeAssertionError");
 777 void    runtime_newErrorString(String, Eface*)
 778      __asm__ (GOSYM_PREFIX "runtime.NewErrorString");
 779 void    runtime_newErrorCString(const char*, Eface*)
 780      __asm__ (GOSYM_PREFIX "runtime.NewErrorCString");
 781
 782 /*
 783  * wrapped for go users
 784  */
 785 void    runtime_semacquire(uint32 volatile *, bool);
 786 void    runtime_semrelease(uint32 volatile *);
 787 int32   runtime_gomaxprocsfunc(int32 n);
 788 void    runtime_procyield(uint32);
 789 void    runtime_osyield(void);
 790 void    runtime_lockOSThread(void);
 791 void    runtime_unlockOSThread(void);
 792 bool    runtime_lockedOSThread(void);
 793
 794 bool    runtime_showframe(String, bool);
 795 void    runtime_printcreatedby(G*);
 796
 797 uintptr runtime_memlimit(void);
 798
 799 #define ISNAN(f) __builtin_isnan(f)
 800
 801 enum
 802 {
 803         UseSpanType = 0,
 804 };
 805
 806 #define runtime_setitimer setitimer
 807
 808 void    runtime_check(void);
 809
 810 // A list of global variables that the garbage collector must scan.
 811 struct root_list {
 812         struct root_list *next;
 813         struct root {
 814                 void *decl;
 815                 size_t size;
 816         } roots[];
 817 };
 818
 819 void    __go_register_gc_roots(struct root_list*);
 820
 821 // Size of stack space allocated using Go's allocator.
 822 // This will be 0 when using split stacks, as in that case
 823 // the stacks are allocated by the splitstack library.
 824 extern uintptr runtime_stacks_sys;
 825
 826 struct backtrace_state;
 827 extern struct backtrace_state *__go_get_backtrace_state(void);
 828 extern _Bool __go_file_line(uintptr, String*, String*, intgo *);
 829 extern byte* runtime_progname();
 830 extern void runtime_main(void*);
 831 extern uint32 runtime_in_callers;
 832
 833 int32 getproccount(void);
 834
 835 #define PREFETCH(p) __builtin_prefetch(p)
 836
 837 void    __go_set_closure(void*);
 838 void*   __go_get_closure(void);
 839
 840 bool    runtime_gcwaiting(void);
 841 void    runtime_badsignal(int);
 842 Defer*  runtime_newdefer(void);
 843 void    runtime_freedefer(Defer*);
 844
 845 struct time_now_ret
 846 {
 847   int64_t sec;
 848   int32_t nsec;
 849 };
 850
 851 struct time_now_ret now() __asm__ (GOSYM_PREFIX "time.now")
 852   __attribute__ ((no_split_stack));