Source file src/runtime/runtime1.go

     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  package runtime
     6  
     7  import (
     8  	"internal/bytealg"
     9  	"internal/goarch"
    10  	"internal/runtime/atomic"
    11  	"unsafe"
    12  )
    13  
    14  // Keep a cached value to make gotraceback fast,
    15  // since we call it on every call to gentraceback.
    16  // The cached value is a uint32 in which the low bits
    17  // are the "crash" and "all" settings and the remaining
    18  // bits are the traceback value (0 off, 1 on, 2 include system).
    19  const (
    20  	tracebackCrash = 1 << iota
    21  	tracebackAll
    22  	tracebackShift = iota
    23  )
    24  
    25  var traceback_cache uint32 = 2 << tracebackShift
    26  var traceback_env uint32
    27  
    28  // gotraceback returns the current traceback settings.
    29  //
    30  // If level is 0, suppress all tracebacks.
    31  // If level is 1, show tracebacks, but exclude runtime frames.
    32  // If level is 2, show tracebacks including runtime frames.
    33  // If all is set, print all goroutine stacks. Otherwise, print just the current goroutine.
    34  // If crash is set, crash (core dump, etc) after tracebacking.
    35  //
    36  //go:nosplit
    37  func gotraceback() (level int32, all, crash bool) {
    38  	gp := getg()
    39  	t := atomic.Load(&traceback_cache)
    40  	crash = t&tracebackCrash != 0
    41  	all = gp.m.throwing >= throwTypeUser || t&tracebackAll != 0
    42  	if gp.m.traceback != 0 {
    43  		level = int32(gp.m.traceback)
    44  	} else if gp.m.throwing >= throwTypeRuntime {
    45  		// Always include runtime frames in runtime throws unless
    46  		// otherwise overridden by m.traceback.
    47  		level = 2
    48  	} else {
    49  		level = int32(t >> tracebackShift)
    50  	}
    51  	return
    52  }
    53  
    54  var (
    55  	argc int32
    56  	argv **byte
    57  )
    58  
    59  // nosplit for use in linux startup sysargs.
    60  //
    61  //go:nosplit
    62  func argv_index(argv **byte, i int32) *byte {
    63  	return *(**byte)(add(unsafe.Pointer(argv), uintptr(i)*goarch.PtrSize))
    64  }
    65  
    66  func args(c int32, v **byte) {
    67  	argc = c
    68  	argv = v
    69  	sysargs(c, v)
    70  }
    71  
    72  func goargs() {
    73  	if GOOS == "windows" {
    74  		return
    75  	}
    76  	argslice = make([]string, argc)
    77  	for i := int32(0); i < argc; i++ {
    78  		argslice[i] = gostringnocopy(argv_index(argv, i))
    79  	}
    80  }
    81  
    82  func goenvs_unix() {
    83  	// TODO(austin): ppc64 in dynamic linking mode doesn't
    84  	// guarantee env[] will immediately follow argv. Might cause
    85  	// problems.
    86  	n := int32(0)
    87  	for argv_index(argv, argc+1+n) != nil {
    88  		n++
    89  	}
    90  
    91  	envs = make([]string, n)
    92  	for i := int32(0); i < n; i++ {
    93  		envs[i] = gostring(argv_index(argv, argc+1+i))
    94  	}
    95  }
    96  
    97  func environ() []string {
    98  	return envs
    99  }
   100  
   101  // TODO: These should be locals in testAtomic64, but we don't 8-byte
   102  // align stack variables on 386.
   103  var test_z64, test_x64 uint64
   104  
   105  func testAtomic64() {
   106  	test_z64 = 42
   107  	test_x64 = 0
   108  	if atomic.Cas64(&test_z64, test_x64, 1) {
   109  		throw("cas64 failed")
   110  	}
   111  	if test_x64 != 0 {
   112  		throw("cas64 failed")
   113  	}
   114  	test_x64 = 42
   115  	if !atomic.Cas64(&test_z64, test_x64, 1) {
   116  		throw("cas64 failed")
   117  	}
   118  	if test_x64 != 42 || test_z64 != 1 {
   119  		throw("cas64 failed")
   120  	}
   121  	if atomic.Load64(&test_z64) != 1 {
   122  		throw("load64 failed")
   123  	}
   124  	atomic.Store64(&test_z64, (1<<40)+1)
   125  	if atomic.Load64(&test_z64) != (1<<40)+1 {
   126  		throw("store64 failed")
   127  	}
   128  	if atomic.Xadd64(&test_z64, (1<<40)+1) != (2<<40)+2 {
   129  		throw("xadd64 failed")
   130  	}
   131  	if atomic.Load64(&test_z64) != (2<<40)+2 {
   132  		throw("xadd64 failed")
   133  	}
   134  	if atomic.Xchg64(&test_z64, (3<<40)+3) != (2<<40)+2 {
   135  		throw("xchg64 failed")
   136  	}
   137  	if atomic.Load64(&test_z64) != (3<<40)+3 {
   138  		throw("xchg64 failed")
   139  	}
   140  }
   141  
   142  func check() {
   143  	var (
   144  		a     int8
   145  		b     uint8
   146  		c     int16
   147  		d     uint16
   148  		e     int32
   149  		f     uint32
   150  		g     int64
   151  		h     uint64
   152  		i, i1 float32
   153  		j, j1 float64
   154  		k     unsafe.Pointer
   155  		l     *uint16
   156  		m     [4]byte
   157  	)
   158  	type x1t struct {
   159  		x uint8
   160  	}
   161  	type y1t struct {
   162  		x1 x1t
   163  		y  uint8
   164  	}
   165  	var x1 x1t
   166  	var y1 y1t
   167  
   168  	if unsafe.Sizeof(a) != 1 {
   169  		throw("bad a")
   170  	}
   171  	if unsafe.Sizeof(b) != 1 {
   172  		throw("bad b")
   173  	}
   174  	if unsafe.Sizeof(c) != 2 {
   175  		throw("bad c")
   176  	}
   177  	if unsafe.Sizeof(d) != 2 {
   178  		throw("bad d")
   179  	}
   180  	if unsafe.Sizeof(e) != 4 {
   181  		throw("bad e")
   182  	}
   183  	if unsafe.Sizeof(f) != 4 {
   184  		throw("bad f")
   185  	}
   186  	if unsafe.Sizeof(g) != 8 {
   187  		throw("bad g")
   188  	}
   189  	if unsafe.Sizeof(h) != 8 {
   190  		throw("bad h")
   191  	}
   192  	if unsafe.Sizeof(i) != 4 {
   193  		throw("bad i")
   194  	}
   195  	if unsafe.Sizeof(j) != 8 {
   196  		throw("bad j")
   197  	}
   198  	if unsafe.Sizeof(k) != goarch.PtrSize {
   199  		throw("bad k")
   200  	}
   201  	if unsafe.Sizeof(l) != goarch.PtrSize {
   202  		throw("bad l")
   203  	}
   204  	if unsafe.Sizeof(x1) != 1 {
   205  		throw("bad unsafe.Sizeof x1")
   206  	}
   207  	if unsafe.Offsetof(y1.y) != 1 {
   208  		throw("bad offsetof y1.y")
   209  	}
   210  	if unsafe.Sizeof(y1) != 2 {
   211  		throw("bad unsafe.Sizeof y1")
   212  	}
   213  
   214  	if timediv(12345*1000000000+54321, 1000000000, &e) != 12345 || e != 54321 {
   215  		throw("bad timediv")
   216  	}
   217  
   218  	var z uint32
   219  	z = 1
   220  	if !atomic.Cas(&z, 1, 2) {
   221  		throw("cas1")
   222  	}
   223  	if z != 2 {
   224  		throw("cas2")
   225  	}
   226  
   227  	z = 4
   228  	if atomic.Cas(&z, 5, 6) {
   229  		throw("cas3")
   230  	}
   231  	if z != 4 {
   232  		throw("cas4")
   233  	}
   234  
   235  	z = 0xffffffff
   236  	if !atomic.Cas(&z, 0xffffffff, 0xfffffffe) {
   237  		throw("cas5")
   238  	}
   239  	if z != 0xfffffffe {
   240  		throw("cas6")
   241  	}
   242  
   243  	m = [4]byte{1, 1, 1, 1}
   244  	atomic.Or8(&m[1], 0xf0)
   245  	if m[0] != 1 || m[1] != 0xf1 || m[2] != 1 || m[3] != 1 {
   246  		throw("atomicor8")
   247  	}
   248  
   249  	m = [4]byte{0xff, 0xff, 0xff, 0xff}
   250  	atomic.And8(&m[1], 0x1)
   251  	if m[0] != 0xff || m[1] != 0x1 || m[2] != 0xff || m[3] != 0xff {
   252  		throw("atomicand8")
   253  	}
   254  
   255  	*(*uint64)(unsafe.Pointer(&j)) = ^uint64(0)
   256  	if j == j {
   257  		throw("float64nan")
   258  	}
   259  	if !(j != j) {
   260  		throw("float64nan1")
   261  	}
   262  
   263  	*(*uint64)(unsafe.Pointer(&j1)) = ^uint64(1)
   264  	if j == j1 {
   265  		throw("float64nan2")
   266  	}
   267  	if !(j != j1) {
   268  		throw("float64nan3")
   269  	}
   270  
   271  	*(*uint32)(unsafe.Pointer(&i)) = ^uint32(0)
   272  	if i == i {
   273  		throw("float32nan")
   274  	}
   275  	if i == i {
   276  		throw("float32nan1")
   277  	}
   278  
   279  	*(*uint32)(unsafe.Pointer(&i1)) = ^uint32(1)
   280  	if i == i1 {
   281  		throw("float32nan2")
   282  	}
   283  	if i == i1 {
   284  		throw("float32nan3")
   285  	}
   286  
   287  	testAtomic64()
   288  
   289  	if fixedStack != round2(fixedStack) {
   290  		throw("FixedStack is not power-of-2")
   291  	}
   292  
   293  	if !checkASM() {
   294  		throw("assembly checks failed")
   295  	}
   296  }
   297  
   298  type dbgVar struct {
   299  	name   string
   300  	value  *int32        // for variables that can only be set at startup
   301  	atomic *atomic.Int32 // for variables that can be changed during execution
   302  	def    int32         // default value (ideally zero)
   303  }
   304  
   305  // Holds variables parsed from GODEBUG env var,
   306  // except for "memprofilerate" since there is an
   307  // existing int var for that value, which may
   308  // already have an initial value.
   309  var debug struct {
   310  	cgocheck                 int32
   311  	clobberfree              int32
   312  	disablethp               int32
   313  	dontfreezetheworld       int32
   314  	efence                   int32
   315  	gccheckmark              int32
   316  	gcpacertrace             int32
   317  	gcshrinkstackoff         int32
   318  	gcstoptheworld           int32
   319  	gctrace                  int32
   320  	invalidptr               int32
   321  	madvdontneed             int32 // for Linux; issue 28466
   322  	runtimeContentionStacks  atomic.Int32
   323  	scavtrace                int32
   324  	scheddetail              int32
   325  	schedtrace               int32
   326  	tracebackancestors       int32
   327  	asyncpreemptoff          int32
   328  	harddecommit             int32
   329  	adaptivestackstart       int32
   330  	tracefpunwindoff         int32
   331  	traceadvanceperiod       int32
   332  	traceCheckStackOwnership int32
   333  
   334  	// debug.malloc is used as a combined debug check
   335  	// in the malloc function and should be set
   336  	// if any of the below debug options is != 0.
   337  	malloc    bool
   338  	inittrace int32
   339  	sbrk      int32
   340  	// traceallocfree controls whether execution traces contain
   341  	// detailed trace data about memory allocation. This value
   342  	// affects debug.malloc only if it is != 0 and the execution
   343  	// tracer is enabled, in which case debug.malloc will be
   344  	// set to "true" if it isn't already while tracing is enabled.
   345  	// It will be set while the world is stopped, so it's safe.
   346  	// The value of traceallocfree can be changed any time in response
   347  	// to os.Setenv("GODEBUG").
   348  	traceallocfree atomic.Int32
   349  
   350  	panicnil atomic.Int32
   351  
   352  	// asynctimerchan controls whether timer channels
   353  	// behave asynchronously (as in Go 1.22 and earlier)
   354  	// instead of their Go 1.23+ synchronous behavior.
   355  	// The value can change at any time (in response to os.Setenv("GODEBUG"))
   356  	// and affects all extant timer channels immediately.
   357  	// Programs wouldn't normally change over an execution,
   358  	// but allowing it is convenient for testing and for programs
   359  	// that do an os.Setenv in main.init or main.main.
   360  	asynctimerchan atomic.Int32
   361  }
   362  
   363  var dbgvars = []*dbgVar{
   364  	{name: "adaptivestackstart", value: &debug.adaptivestackstart},
   365  	{name: "asyncpreemptoff", value: &debug.asyncpreemptoff},
   366  	{name: "asynctimerchan", atomic: &debug.asynctimerchan},
   367  	{name: "cgocheck", value: &debug.cgocheck},
   368  	{name: "clobberfree", value: &debug.clobberfree},
   369  	{name: "disablethp", value: &debug.disablethp},
   370  	{name: "dontfreezetheworld", value: &debug.dontfreezetheworld},
   371  	{name: "efence", value: &debug.efence},
   372  	{name: "gccheckmark", value: &debug.gccheckmark},
   373  	{name: "gcpacertrace", value: &debug.gcpacertrace},
   374  	{name: "gcshrinkstackoff", value: &debug.gcshrinkstackoff},
   375  	{name: "gcstoptheworld", value: &debug.gcstoptheworld},
   376  	{name: "gctrace", value: &debug.gctrace},
   377  	{name: "harddecommit", value: &debug.harddecommit},
   378  	{name: "inittrace", value: &debug.inittrace},
   379  	{name: "invalidptr", value: &debug.invalidptr},
   380  	{name: "madvdontneed", value: &debug.madvdontneed},
   381  	{name: "panicnil", atomic: &debug.panicnil},
   382  	{name: "runtimecontentionstacks", atomic: &debug.runtimeContentionStacks},
   383  	{name: "sbrk", value: &debug.sbrk},
   384  	{name: "scavtrace", value: &debug.scavtrace},
   385  	{name: "scheddetail", value: &debug.scheddetail},
   386  	{name: "schedtrace", value: &debug.schedtrace},
   387  	{name: "traceadvanceperiod", value: &debug.traceadvanceperiod},
   388  	{name: "traceallocfree", atomic: &debug.traceallocfree},
   389  	{name: "tracecheckstackownership", value: &debug.traceCheckStackOwnership},
   390  	{name: "tracebackancestors", value: &debug.tracebackancestors},
   391  	{name: "tracefpunwindoff", value: &debug.tracefpunwindoff},
   392  }
   393  
   394  func parsedebugvars() {
   395  	// defaults
   396  	debug.cgocheck = 1
   397  	debug.invalidptr = 1
   398  	debug.adaptivestackstart = 1 // set this to 0 to turn larger initial goroutine stacks off
   399  	if GOOS == "linux" {
   400  		// On Linux, MADV_FREE is faster than MADV_DONTNEED,
   401  		// but doesn't affect many of the statistics that
   402  		// MADV_DONTNEED does until the memory is actually
   403  		// reclaimed. This generally leads to poor user
   404  		// experience, like confusing stats in top and other
   405  		// monitoring tools; and bad integration with
   406  		// management systems that respond to memory usage.
   407  		// Hence, default to MADV_DONTNEED.
   408  		debug.madvdontneed = 1
   409  	}
   410  	debug.traceadvanceperiod = defaultTraceAdvancePeriod
   411  
   412  	godebug := gogetenv("GODEBUG")
   413  
   414  	p := new(string)
   415  	*p = godebug
   416  	godebugEnv.Store(p)
   417  
   418  	// apply runtime defaults, if any
   419  	for _, v := range dbgvars {
   420  		if v.def != 0 {
   421  			// Every var should have either v.value or v.atomic set.
   422  			if v.value != nil {
   423  				*v.value = v.def
   424  			} else if v.atomic != nil {
   425  				v.atomic.Store(v.def)
   426  			}
   427  		}
   428  	}
   429  
   430  	// apply compile-time GODEBUG settings
   431  	parsegodebug(godebugDefault, nil)
   432  
   433  	// apply environment settings
   434  	parsegodebug(godebug, nil)
   435  
   436  	debug.malloc = (debug.inittrace | debug.sbrk) != 0
   437  
   438  	setTraceback(gogetenv("GOTRACEBACK"))
   439  	traceback_env = traceback_cache
   440  }
   441  
   442  // reparsedebugvars reparses the runtime's debug variables
   443  // because the environment variable has been changed to env.
   444  func reparsedebugvars(env string) {
   445  	seen := make(map[string]bool)
   446  	// apply environment settings
   447  	parsegodebug(env, seen)
   448  	// apply compile-time GODEBUG settings for as-yet-unseen variables
   449  	parsegodebug(godebugDefault, seen)
   450  	// apply defaults for as-yet-unseen variables
   451  	for _, v := range dbgvars {
   452  		if v.atomic != nil && !seen[v.name] {
   453  			v.atomic.Store(0)
   454  		}
   455  	}
   456  }
   457  
   458  // parsegodebug parses the godebug string, updating variables listed in dbgvars.
   459  // If seen == nil, this is startup time and we process the string left to right
   460  // overwriting older settings with newer ones.
   461  // If seen != nil, $GODEBUG has changed and we are doing an
   462  // incremental update. To avoid flapping in the case where a value is
   463  // set multiple times (perhaps in the default and the environment,
   464  // or perhaps twice in the environment), we process the string right-to-left
   465  // and only change values not already seen. After doing this for both
   466  // the environment and the default settings, the caller must also call
   467  // cleargodebug(seen) to reset any now-unset values back to their defaults.
   468  func parsegodebug(godebug string, seen map[string]bool) {
   469  	for p := godebug; p != ""; {
   470  		var field string
   471  		if seen == nil {
   472  			// startup: process left to right, overwriting older settings with newer
   473  			i := bytealg.IndexByteString(p, ',')
   474  			if i < 0 {
   475  				field, p = p, ""
   476  			} else {
   477  				field, p = p[:i], p[i+1:]
   478  			}
   479  		} else {
   480  			// incremental update: process right to left, updating and skipping seen
   481  			i := len(p) - 1
   482  			for i >= 0 && p[i] != ',' {
   483  				i--
   484  			}
   485  			if i < 0 {
   486  				p, field = "", p
   487  			} else {
   488  				p, field = p[:i], p[i+1:]
   489  			}
   490  		}
   491  		i := bytealg.IndexByteString(field, '=')
   492  		if i < 0 {
   493  			continue
   494  		}
   495  		key, value := field[:i], field[i+1:]
   496  		if seen[key] {
   497  			continue
   498  		}
   499  		if seen != nil {
   500  			seen[key] = true
   501  		}
   502  
   503  		// Update MemProfileRate directly here since it
   504  		// is int, not int32, and should only be updated
   505  		// if specified in GODEBUG.
   506  		if seen == nil && key == "memprofilerate" {
   507  			if n, ok := atoi(value); ok {
   508  				MemProfileRate = n
   509  			}
   510  		} else {
   511  			for _, v := range dbgvars {
   512  				if v.name == key {
   513  					if n, ok := atoi32(value); ok {
   514  						if seen == nil && v.value != nil {
   515  							*v.value = n
   516  						} else if v.atomic != nil {
   517  							v.atomic.Store(n)
   518  						}
   519  					}
   520  				}
   521  			}
   522  		}
   523  	}
   524  
   525  	if debug.cgocheck > 1 {
   526  		throw("cgocheck > 1 mode is no longer supported at runtime. Use GOEXPERIMENT=cgocheck2 at build time instead.")
   527  	}
   528  }
   529  
   530  //go:linkname setTraceback runtime/debug.SetTraceback
   531  func setTraceback(level string) {
   532  	var t uint32
   533  	switch level {
   534  	case "none":
   535  		t = 0
   536  	case "single", "":
   537  		t = 1 << tracebackShift
   538  	case "all":
   539  		t = 1<<tracebackShift | tracebackAll
   540  	case "system":
   541  		t = 2<<tracebackShift | tracebackAll
   542  	case "crash":
   543  		t = 2<<tracebackShift | tracebackAll | tracebackCrash
   544  	case "wer":
   545  		if GOOS == "windows" {
   546  			t = 2<<tracebackShift | tracebackAll | tracebackCrash
   547  			enableWER()
   548  			break
   549  		}
   550  		fallthrough
   551  	default:
   552  		t = tracebackAll
   553  		if n, ok := atoi(level); ok && n == int(uint32(n)) {
   554  			t |= uint32(n) << tracebackShift
   555  		}
   556  	}
   557  	// when C owns the process, simply exit'ing the process on fatal errors
   558  	// and panics is surprising. Be louder and abort instead.
   559  	if islibrary || isarchive {
   560  		t |= tracebackCrash
   561  	}
   562  
   563  	t |= traceback_env
   564  
   565  	atomic.Store(&traceback_cache, t)
   566  }
   567  
   568  // Poor mans 64-bit division.
   569  // This is a very special function, do not use it if you are not sure what you are doing.
   570  // int64 division is lowered into _divv() call on 386, which does not fit into nosplit functions.
   571  // Handles overflow in a time-specific manner.
   572  // This keeps us within no-split stack limits on 32-bit processors.
   573  //
   574  //go:nosplit
   575  func timediv(v int64, div int32, rem *int32) int32 {
   576  	res := int32(0)
   577  	for bit := 30; bit >= 0; bit-- {
   578  		if v >= int64(div)<<uint(bit) {
   579  			v = v - (int64(div) << uint(bit))
   580  			// Before this for loop, res was 0, thus all these
   581  			// power of 2 increments are now just bitsets.
   582  			res |= 1 << uint(bit)
   583  		}
   584  	}
   585  	if v >= int64(div) {
   586  		if rem != nil {
   587  			*rem = 0
   588  		}
   589  		return 0x7fffffff
   590  	}
   591  	if rem != nil {
   592  		*rem = int32(v)
   593  	}
   594  	return res
   595  }
   596  
   597  // Helpers for Go. Must be NOSPLIT, must only call NOSPLIT functions, and must not block.
   598  
   599  //go:nosplit
   600  func acquirem() *m {
   601  	gp := getg()
   602  	gp.m.locks++
   603  	return gp.m
   604  }
   605  
   606  //go:nosplit
   607  func releasem(mp *m) {
   608  	gp := getg()
   609  	mp.locks--
   610  	if mp.locks == 0 && gp.preempt {
   611  		// restore the preemption request in case we've cleared it in newstack
   612  		gp.stackguard0 = stackPreempt
   613  	}
   614  }
   615  
   616  //go:linkname reflect_typelinks reflect.typelinks
   617  func reflect_typelinks() ([]unsafe.Pointer, [][]int32) {
   618  	modules := activeModules()
   619  	sections := []unsafe.Pointer{unsafe.Pointer(modules[0].types)}
   620  	ret := [][]int32{modules[0].typelinks}
   621  	for _, md := range modules[1:] {
   622  		sections = append(sections, unsafe.Pointer(md.types))
   623  		ret = append(ret, md.typelinks)
   624  	}
   625  	return sections, ret
   626  }
   627  
   628  // reflect_resolveNameOff resolves a name offset from a base pointer.
   629  //
   630  //go:linkname reflect_resolveNameOff reflect.resolveNameOff
   631  func reflect_resolveNameOff(ptrInModule unsafe.Pointer, off int32) unsafe.Pointer {
   632  	return unsafe.Pointer(resolveNameOff(ptrInModule, nameOff(off)).Bytes)
   633  }
   634  
   635  // reflect_resolveTypeOff resolves an *rtype offset from a base type.
   636  //
   637  //go:linkname reflect_resolveTypeOff reflect.resolveTypeOff
   638  func reflect_resolveTypeOff(rtype unsafe.Pointer, off int32) unsafe.Pointer {
   639  	return unsafe.Pointer(toRType((*_type)(rtype)).typeOff(typeOff(off)))
   640  }
   641  
   642  // reflect_resolveTextOff resolves a function pointer offset from a base type.
   643  //
   644  //go:linkname reflect_resolveTextOff reflect.resolveTextOff
   645  func reflect_resolveTextOff(rtype unsafe.Pointer, off int32) unsafe.Pointer {
   646  	return toRType((*_type)(rtype)).textOff(textOff(off))
   647  }
   648  
   649  // reflectlite_resolveNameOff resolves a name offset from a base pointer.
   650  //
   651  //go:linkname reflectlite_resolveNameOff internal/reflectlite.resolveNameOff
   652  func reflectlite_resolveNameOff(ptrInModule unsafe.Pointer, off int32) unsafe.Pointer {
   653  	return unsafe.Pointer(resolveNameOff(ptrInModule, nameOff(off)).Bytes)
   654  }
   655  
   656  // reflectlite_resolveTypeOff resolves an *rtype offset from a base type.
   657  //
   658  //go:linkname reflectlite_resolveTypeOff internal/reflectlite.resolveTypeOff
   659  func reflectlite_resolveTypeOff(rtype unsafe.Pointer, off int32) unsafe.Pointer {
   660  	return unsafe.Pointer(toRType((*_type)(rtype)).typeOff(typeOff(off)))
   661  }
   662  
   663  // reflect_addReflectOff adds a pointer to the reflection offset lookup map.
   664  //
   665  //go:linkname reflect_addReflectOff reflect.addReflectOff
   666  func reflect_addReflectOff(ptr unsafe.Pointer) int32 {
   667  	reflectOffsLock()
   668  	if reflectOffs.m == nil {
   669  		reflectOffs.m = make(map[int32]unsafe.Pointer)
   670  		reflectOffs.minv = make(map[unsafe.Pointer]int32)
   671  		reflectOffs.next = -1
   672  	}
   673  	id, found := reflectOffs.minv[ptr]
   674  	if !found {
   675  		id = reflectOffs.next
   676  		reflectOffs.next-- // use negative offsets as IDs to aid debugging
   677  		reflectOffs.m[id] = ptr
   678  		reflectOffs.minv[ptr] = id
   679  	}
   680  	reflectOffsUnlock()
   681  	return id
   682  }
   683  

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