Source file src/runtime/export_test.go

     1  // Copyright 2010 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  // Export guts for testing.
     6  
     7  package runtime
     8  
     9  import (
    10  	"internal/abi"
    11  	"internal/goarch"
    12  	"internal/goos"
    13  	"internal/runtime/atomic"
    14  	"internal/runtime/sys"
    15  	"unsafe"
    16  )
    17  
    18  var Fadd64 = fadd64
    19  var Fsub64 = fsub64
    20  var Fmul64 = fmul64
    21  var Fdiv64 = fdiv64
    22  var F64to32 = f64to32
    23  var F32to64 = f32to64
    24  var Fcmp64 = fcmp64
    25  var Fintto64 = fintto64
    26  var F64toint = f64toint
    27  
    28  var Entersyscall = entersyscall
    29  var Exitsyscall = exitsyscall
    30  var LockedOSThread = lockedOSThread
    31  var Xadduintptr = atomic.Xadduintptr
    32  
    33  var ReadRandomFailed = &readRandomFailed
    34  
    35  var Fastlog2 = fastlog2
    36  
    37  var Atoi = atoi
    38  var Atoi32 = atoi32
    39  var ParseByteCount = parseByteCount
    40  
    41  var Nanotime = nanotime
    42  var NetpollBreak = netpollBreak
    43  var Usleep = usleep
    44  
    45  var PhysPageSize = physPageSize
    46  var PhysHugePageSize = physHugePageSize
    47  
    48  var NetpollGenericInit = netpollGenericInit
    49  
    50  var Memmove = memmove
    51  var MemclrNoHeapPointers = memclrNoHeapPointers
    52  
    53  var CgoCheckPointer = cgoCheckPointer
    54  
    55  const CrashStackImplemented = crashStackImplemented
    56  
    57  const TracebackInnerFrames = tracebackInnerFrames
    58  const TracebackOuterFrames = tracebackOuterFrames
    59  
    60  var MapKeys = keys
    61  var MapValues = values
    62  
    63  var LockPartialOrder = lockPartialOrder
    64  
    65  type TimeTimer = timeTimer
    66  
    67  type LockRank lockRank
    68  
    69  func (l LockRank) String() string {
    70  	return lockRank(l).String()
    71  }
    72  
    73  const PreemptMSupported = preemptMSupported
    74  
    75  type LFNode struct {
    76  	Next    uint64
    77  	Pushcnt uintptr
    78  }
    79  
    80  func LFStackPush(head *uint64, node *LFNode) {
    81  	(*lfstack)(head).push((*lfnode)(unsafe.Pointer(node)))
    82  }
    83  
    84  func LFStackPop(head *uint64) *LFNode {
    85  	return (*LFNode)((*lfstack)(head).pop())
    86  }
    87  func LFNodeValidate(node *LFNode) {
    88  	lfnodeValidate((*lfnode)(unsafe.Pointer(node)))
    89  }
    90  
    91  func Netpoll(delta int64) {
    92  	systemstack(func() {
    93  		netpoll(delta)
    94  	})
    95  }
    96  
    97  func PointerMask(x any) (ret []byte) {
    98  	systemstack(func() {
    99  		ret = pointerMask(x)
   100  	})
   101  	return
   102  }
   103  
   104  func RunSchedLocalQueueTest() {
   105  	pp := new(p)
   106  	gs := make([]g, len(pp.runq))
   107  	Escape(gs) // Ensure gs doesn't move, since we use guintptrs
   108  	for i := 0; i < len(pp.runq); i++ {
   109  		if g, _ := runqget(pp); g != nil {
   110  			throw("runq is not empty initially")
   111  		}
   112  		for j := 0; j < i; j++ {
   113  			runqput(pp, &gs[i], false)
   114  		}
   115  		for j := 0; j < i; j++ {
   116  			if g, _ := runqget(pp); g != &gs[i] {
   117  				print("bad element at iter ", i, "/", j, "\n")
   118  				throw("bad element")
   119  			}
   120  		}
   121  		if g, _ := runqget(pp); g != nil {
   122  			throw("runq is not empty afterwards")
   123  		}
   124  	}
   125  }
   126  
   127  func RunSchedLocalQueueStealTest() {
   128  	p1 := new(p)
   129  	p2 := new(p)
   130  	gs := make([]g, len(p1.runq))
   131  	Escape(gs) // Ensure gs doesn't move, since we use guintptrs
   132  	for i := 0; i < len(p1.runq); i++ {
   133  		for j := 0; j < i; j++ {
   134  			gs[j].sig = 0
   135  			runqput(p1, &gs[j], false)
   136  		}
   137  		gp := runqsteal(p2, p1, true)
   138  		s := 0
   139  		if gp != nil {
   140  			s++
   141  			gp.sig++
   142  		}
   143  		for {
   144  			gp, _ = runqget(p2)
   145  			if gp == nil {
   146  				break
   147  			}
   148  			s++
   149  			gp.sig++
   150  		}
   151  		for {
   152  			gp, _ = runqget(p1)
   153  			if gp == nil {
   154  				break
   155  			}
   156  			gp.sig++
   157  		}
   158  		for j := 0; j < i; j++ {
   159  			if gs[j].sig != 1 {
   160  				print("bad element ", j, "(", gs[j].sig, ") at iter ", i, "\n")
   161  				throw("bad element")
   162  			}
   163  		}
   164  		if s != i/2 && s != i/2+1 {
   165  			print("bad steal ", s, ", want ", i/2, " or ", i/2+1, ", iter ", i, "\n")
   166  			throw("bad steal")
   167  		}
   168  	}
   169  }
   170  
   171  func RunSchedLocalQueueEmptyTest(iters int) {
   172  	// Test that runq is not spuriously reported as empty.
   173  	// Runq emptiness affects scheduling decisions and spurious emptiness
   174  	// can lead to underutilization (both runnable Gs and idle Ps coexist
   175  	// for arbitrary long time).
   176  	done := make(chan bool, 1)
   177  	p := new(p)
   178  	gs := make([]g, 2)
   179  	Escape(gs) // Ensure gs doesn't move, since we use guintptrs
   180  	ready := new(uint32)
   181  	for i := 0; i < iters; i++ {
   182  		*ready = 0
   183  		next0 := (i & 1) == 0
   184  		next1 := (i & 2) == 0
   185  		runqput(p, &gs[0], next0)
   186  		go func() {
   187  			for atomic.Xadd(ready, 1); atomic.Load(ready) != 2; {
   188  			}
   189  			if runqempty(p) {
   190  				println("next:", next0, next1)
   191  				throw("queue is empty")
   192  			}
   193  			done <- true
   194  		}()
   195  		for atomic.Xadd(ready, 1); atomic.Load(ready) != 2; {
   196  		}
   197  		runqput(p, &gs[1], next1)
   198  		runqget(p)
   199  		<-done
   200  		runqget(p)
   201  	}
   202  }
   203  
   204  var (
   205  	StringHash = stringHash
   206  	BytesHash  = bytesHash
   207  	Int32Hash  = int32Hash
   208  	Int64Hash  = int64Hash
   209  	MemHash    = memhash
   210  	MemHash32  = memhash32
   211  	MemHash64  = memhash64
   212  	EfaceHash  = efaceHash
   213  	IfaceHash  = ifaceHash
   214  )
   215  
   216  var UseAeshash = &useAeshash
   217  
   218  func MemclrBytes(b []byte) {
   219  	s := (*slice)(unsafe.Pointer(&b))
   220  	memclrNoHeapPointers(s.array, uintptr(s.len))
   221  }
   222  
   223  const HashLoad = hashLoad
   224  
   225  // entry point for testing
   226  func GostringW(w []uint16) (s string) {
   227  	systemstack(func() {
   228  		s = gostringw(&w[0])
   229  	})
   230  	return
   231  }
   232  
   233  var Open = open
   234  var Close = closefd
   235  var Read = read
   236  var Write = write
   237  
   238  func Envs() []string     { return envs }
   239  func SetEnvs(e []string) { envs = e }
   240  
   241  const PtrSize = goarch.PtrSize
   242  
   243  var ForceGCPeriod = &forcegcperiod
   244  
   245  // SetTracebackEnv is like runtime/debug.SetTraceback, but it raises
   246  // the "environment" traceback level, so later calls to
   247  // debug.SetTraceback (e.g., from testing timeouts) can't lower it.
   248  func SetTracebackEnv(level string) {
   249  	setTraceback(level)
   250  	traceback_env = traceback_cache
   251  }
   252  
   253  var ReadUnaligned32 = readUnaligned32
   254  var ReadUnaligned64 = readUnaligned64
   255  
   256  func CountPagesInUse() (pagesInUse, counted uintptr) {
   257  	stw := stopTheWorld(stwForTestCountPagesInUse)
   258  
   259  	pagesInUse = mheap_.pagesInUse.Load()
   260  
   261  	for _, s := range mheap_.allspans {
   262  		if s.state.get() == mSpanInUse {
   263  			counted += s.npages
   264  		}
   265  	}
   266  
   267  	startTheWorld(stw)
   268  
   269  	return
   270  }
   271  
   272  func Fastrand() uint32          { return uint32(rand()) }
   273  func Fastrand64() uint64        { return rand() }
   274  func Fastrandn(n uint32) uint32 { return randn(n) }
   275  
   276  type ProfBuf profBuf
   277  
   278  func NewProfBuf(hdrsize, bufwords, tags int) *ProfBuf {
   279  	return (*ProfBuf)(newProfBuf(hdrsize, bufwords, tags))
   280  }
   281  
   282  func (p *ProfBuf) Write(tag *unsafe.Pointer, now int64, hdr []uint64, stk []uintptr) {
   283  	(*profBuf)(p).write(tag, now, hdr, stk)
   284  }
   285  
   286  const (
   287  	ProfBufBlocking    = profBufBlocking
   288  	ProfBufNonBlocking = profBufNonBlocking
   289  )
   290  
   291  func (p *ProfBuf) Read(mode profBufReadMode) ([]uint64, []unsafe.Pointer, bool) {
   292  	return (*profBuf)(p).read(mode)
   293  }
   294  
   295  func (p *ProfBuf) Close() {
   296  	(*profBuf)(p).close()
   297  }
   298  
   299  type CPUStats = cpuStats
   300  
   301  func ReadCPUStats() CPUStats {
   302  	return work.cpuStats
   303  }
   304  
   305  func ReadMetricsSlow(memStats *MemStats, samplesp unsafe.Pointer, len, cap int) {
   306  	stw := stopTheWorld(stwForTestReadMetricsSlow)
   307  
   308  	// Initialize the metrics beforehand because this could
   309  	// allocate and skew the stats.
   310  	metricsLock()
   311  	initMetrics()
   312  
   313  	systemstack(func() {
   314  		// Donate the racectx to g0. readMetricsLocked calls into the race detector
   315  		// via map access.
   316  		getg().racectx = getg().m.curg.racectx
   317  
   318  		// Read the metrics once before in case it allocates and skews the metrics.
   319  		// readMetricsLocked is designed to only allocate the first time it is called
   320  		// with a given slice of samples. In effect, this extra read tests that this
   321  		// remains true, since otherwise the second readMetricsLocked below could
   322  		// allocate before it returns.
   323  		readMetricsLocked(samplesp, len, cap)
   324  
   325  		// Read memstats first. It's going to flush
   326  		// the mcaches which readMetrics does not do, so
   327  		// going the other way around may result in
   328  		// inconsistent statistics.
   329  		readmemstats_m(memStats)
   330  
   331  		// Read metrics again. We need to be sure we're on the
   332  		// system stack with readmemstats_m so that we don't call into
   333  		// the stack allocator and adjust metrics between there and here.
   334  		readMetricsLocked(samplesp, len, cap)
   335  
   336  		// Undo the donation.
   337  		getg().racectx = 0
   338  	})
   339  	metricsUnlock()
   340  
   341  	startTheWorld(stw)
   342  }
   343  
   344  var DoubleCheckReadMemStats = &doubleCheckReadMemStats
   345  
   346  // ReadMemStatsSlow returns both the runtime-computed MemStats and
   347  // MemStats accumulated by scanning the heap.
   348  func ReadMemStatsSlow() (base, slow MemStats) {
   349  	stw := stopTheWorld(stwForTestReadMemStatsSlow)
   350  
   351  	// Run on the system stack to avoid stack growth allocation.
   352  	systemstack(func() {
   353  		// Make sure stats don't change.
   354  		getg().m.mallocing++
   355  
   356  		readmemstats_m(&base)
   357  
   358  		// Initialize slow from base and zero the fields we're
   359  		// recomputing.
   360  		slow = base
   361  		slow.Alloc = 0
   362  		slow.TotalAlloc = 0
   363  		slow.Mallocs = 0
   364  		slow.Frees = 0
   365  		slow.HeapReleased = 0
   366  		var bySize [_NumSizeClasses]struct {
   367  			Mallocs, Frees uint64
   368  		}
   369  
   370  		// Add up current allocations in spans.
   371  		for _, s := range mheap_.allspans {
   372  			if s.state.get() != mSpanInUse {
   373  				continue
   374  			}
   375  			if s.isUnusedUserArenaChunk() {
   376  				continue
   377  			}
   378  			if sizeclass := s.spanclass.sizeclass(); sizeclass == 0 {
   379  				slow.Mallocs++
   380  				slow.Alloc += uint64(s.elemsize)
   381  			} else {
   382  				slow.Mallocs += uint64(s.allocCount)
   383  				slow.Alloc += uint64(s.allocCount) * uint64(s.elemsize)
   384  				bySize[sizeclass].Mallocs += uint64(s.allocCount)
   385  			}
   386  		}
   387  
   388  		// Add in frees by just reading the stats for those directly.
   389  		var m heapStatsDelta
   390  		memstats.heapStats.unsafeRead(&m)
   391  
   392  		// Collect per-sizeclass free stats.
   393  		var smallFree uint64
   394  		for i := 0; i < _NumSizeClasses; i++ {
   395  			slow.Frees += m.smallFreeCount[i]
   396  			bySize[i].Frees += m.smallFreeCount[i]
   397  			bySize[i].Mallocs += m.smallFreeCount[i]
   398  			smallFree += m.smallFreeCount[i] * uint64(class_to_size[i])
   399  		}
   400  		slow.Frees += m.tinyAllocCount + m.largeFreeCount
   401  		slow.Mallocs += slow.Frees
   402  
   403  		slow.TotalAlloc = slow.Alloc + m.largeFree + smallFree
   404  
   405  		for i := range slow.BySize {
   406  			slow.BySize[i].Mallocs = bySize[i].Mallocs
   407  			slow.BySize[i].Frees = bySize[i].Frees
   408  		}
   409  
   410  		for i := mheap_.pages.start; i < mheap_.pages.end; i++ {
   411  			chunk := mheap_.pages.tryChunkOf(i)
   412  			if chunk == nil {
   413  				continue
   414  			}
   415  			pg := chunk.scavenged.popcntRange(0, pallocChunkPages)
   416  			slow.HeapReleased += uint64(pg) * pageSize
   417  		}
   418  		for _, p := range allp {
   419  			pg := sys.OnesCount64(p.pcache.scav)
   420  			slow.HeapReleased += uint64(pg) * pageSize
   421  		}
   422  
   423  		getg().m.mallocing--
   424  	})
   425  
   426  	startTheWorld(stw)
   427  	return
   428  }
   429  
   430  // ShrinkStackAndVerifyFramePointers attempts to shrink the stack of the current goroutine
   431  // and verifies that unwinding the new stack doesn't crash, even if the old
   432  // stack has been freed or reused (simulated via poisoning).
   433  func ShrinkStackAndVerifyFramePointers() {
   434  	before := stackPoisonCopy
   435  	defer func() { stackPoisonCopy = before }()
   436  	stackPoisonCopy = 1
   437  
   438  	gp := getg()
   439  	systemstack(func() {
   440  		shrinkstack(gp)
   441  	})
   442  	// If our new stack contains frame pointers into the old stack, this will
   443  	// crash because the old stack has been poisoned.
   444  	FPCallers(make([]uintptr, 1024))
   445  }
   446  
   447  // BlockOnSystemStack switches to the system stack, prints "x\n" to
   448  // stderr, and blocks in a stack containing
   449  // "runtime.blockOnSystemStackInternal".
   450  func BlockOnSystemStack() {
   451  	systemstack(blockOnSystemStackInternal)
   452  }
   453  
   454  func blockOnSystemStackInternal() {
   455  	print("x\n")
   456  	lock(&deadlock)
   457  	lock(&deadlock)
   458  }
   459  
   460  type RWMutex struct {
   461  	rw rwmutex
   462  }
   463  
   464  func (rw *RWMutex) Init() {
   465  	rw.rw.init(lockRankTestR, lockRankTestRInternal, lockRankTestW)
   466  }
   467  
   468  func (rw *RWMutex) RLock() {
   469  	rw.rw.rlock()
   470  }
   471  
   472  func (rw *RWMutex) RUnlock() {
   473  	rw.rw.runlock()
   474  }
   475  
   476  func (rw *RWMutex) Lock() {
   477  	rw.rw.lock()
   478  }
   479  
   480  func (rw *RWMutex) Unlock() {
   481  	rw.rw.unlock()
   482  }
   483  
   484  func LockOSCounts() (external, internal uint32) {
   485  	gp := getg()
   486  	if gp.m.lockedExt+gp.m.lockedInt == 0 {
   487  		if gp.lockedm != 0 {
   488  			panic("lockedm on non-locked goroutine")
   489  		}
   490  	} else {
   491  		if gp.lockedm == 0 {
   492  			panic("nil lockedm on locked goroutine")
   493  		}
   494  	}
   495  	return gp.m.lockedExt, gp.m.lockedInt
   496  }
   497  
   498  //go:noinline
   499  func TracebackSystemstack(stk []uintptr, i int) int {
   500  	if i == 0 {
   501  		pc, sp := sys.GetCallerPC(), sys.GetCallerSP()
   502  		var u unwinder
   503  		u.initAt(pc, sp, 0, getg(), unwindJumpStack) // Don't ignore errors, for testing
   504  		return tracebackPCs(&u, 0, stk)
   505  	}
   506  	n := 0
   507  	systemstack(func() {
   508  		n = TracebackSystemstack(stk, i-1)
   509  	})
   510  	return n
   511  }
   512  
   513  func KeepNArenaHints(n int) {
   514  	hint := mheap_.arenaHints
   515  	for i := 1; i < n; i++ {
   516  		hint = hint.next
   517  		if hint == nil {
   518  			return
   519  		}
   520  	}
   521  	hint.next = nil
   522  }
   523  
   524  // MapNextArenaHint reserves a page at the next arena growth hint,
   525  // preventing the arena from growing there, and returns the range of
   526  // addresses that are no longer viable.
   527  //
   528  // This may fail to reserve memory. If it fails, it still returns the
   529  // address range it attempted to reserve.
   530  func MapNextArenaHint() (start, end uintptr, ok bool) {
   531  	hint := mheap_.arenaHints
   532  	addr := hint.addr
   533  	if hint.down {
   534  		start, end = addr-heapArenaBytes, addr
   535  		addr -= physPageSize
   536  	} else {
   537  		start, end = addr, addr+heapArenaBytes
   538  	}
   539  	got := sysReserve(unsafe.Pointer(addr), physPageSize)
   540  	ok = (addr == uintptr(got))
   541  	if !ok {
   542  		// We were unable to get the requested reservation.
   543  		// Release what we did get and fail.
   544  		sysFreeOS(got, physPageSize)
   545  	}
   546  	return
   547  }
   548  
   549  func GetNextArenaHint() uintptr {
   550  	return mheap_.arenaHints.addr
   551  }
   552  
   553  type G = g
   554  
   555  type Sudog = sudog
   556  
   557  func Getg() *G {
   558  	return getg()
   559  }
   560  
   561  func Goid() uint64 {
   562  	return getg().goid
   563  }
   564  
   565  func GIsWaitingOnMutex(gp *G) bool {
   566  	return readgstatus(gp) == _Gwaiting && gp.waitreason.isMutexWait()
   567  }
   568  
   569  var CasGStatusAlwaysTrack = &casgstatusAlwaysTrack
   570  
   571  //go:noinline
   572  func PanicForTesting(b []byte, i int) byte {
   573  	return unexportedPanicForTesting(b, i)
   574  }
   575  
   576  //go:noinline
   577  func unexportedPanicForTesting(b []byte, i int) byte {
   578  	return b[i]
   579  }
   580  
   581  func G0StackOverflow() {
   582  	systemstack(func() {
   583  		g0 := getg()
   584  		sp := sys.GetCallerSP()
   585  		// The stack bounds for g0 stack is not always precise.
   586  		// Use an artificially small stack, to trigger a stack overflow
   587  		// without actually run out of the system stack (which may seg fault).
   588  		g0.stack.lo = sp - 4096 - stackSystem
   589  		g0.stackguard0 = g0.stack.lo + stackGuard
   590  		g0.stackguard1 = g0.stackguard0
   591  
   592  		stackOverflow(nil)
   593  	})
   594  }
   595  
   596  func stackOverflow(x *byte) {
   597  	var buf [256]byte
   598  	stackOverflow(&buf[0])
   599  }
   600  
   601  func RunGetgThreadSwitchTest() {
   602  	// Test that getg works correctly with thread switch.
   603  	// With gccgo, if we generate getg inlined, the backend
   604  	// may cache the address of the TLS variable, which
   605  	// will become invalid after a thread switch. This test
   606  	// checks that the bad caching doesn't happen.
   607  
   608  	ch := make(chan int)
   609  	go func(ch chan int) {
   610  		ch <- 5
   611  		LockOSThread()
   612  	}(ch)
   613  
   614  	g1 := getg()
   615  
   616  	// Block on a receive. This is likely to get us a thread
   617  	// switch. If we yield to the sender goroutine, it will
   618  	// lock the thread, forcing us to resume on a different
   619  	// thread.
   620  	<-ch
   621  
   622  	g2 := getg()
   623  	if g1 != g2 {
   624  		panic("g1 != g2")
   625  	}
   626  
   627  	// Also test getg after some control flow, as the
   628  	// backend is sensitive to control flow.
   629  	g3 := getg()
   630  	if g1 != g3 {
   631  		panic("g1 != g3")
   632  	}
   633  }
   634  
   635  const (
   636  	PageSize         = pageSize
   637  	PallocChunkPages = pallocChunkPages
   638  	PageAlloc64Bit   = pageAlloc64Bit
   639  	PallocSumBytes   = pallocSumBytes
   640  )
   641  
   642  // Expose pallocSum for testing.
   643  type PallocSum pallocSum
   644  
   645  func PackPallocSum(start, max, end uint) PallocSum { return PallocSum(packPallocSum(start, max, end)) }
   646  func (m PallocSum) Start() uint                    { return pallocSum(m).start() }
   647  func (m PallocSum) Max() uint                      { return pallocSum(m).max() }
   648  func (m PallocSum) End() uint                      { return pallocSum(m).end() }
   649  
   650  // Expose pallocBits for testing.
   651  type PallocBits pallocBits
   652  
   653  func (b *PallocBits) Find(npages uintptr, searchIdx uint) (uint, uint) {
   654  	return (*pallocBits)(b).find(npages, searchIdx)
   655  }
   656  func (b *PallocBits) AllocRange(i, n uint)       { (*pallocBits)(b).allocRange(i, n) }
   657  func (b *PallocBits) Free(i, n uint)             { (*pallocBits)(b).free(i, n) }
   658  func (b *PallocBits) Summarize() PallocSum       { return PallocSum((*pallocBits)(b).summarize()) }
   659  func (b *PallocBits) PopcntRange(i, n uint) uint { return (*pageBits)(b).popcntRange(i, n) }
   660  
   661  // SummarizeSlow is a slow but more obviously correct implementation
   662  // of (*pallocBits).summarize. Used for testing.
   663  func SummarizeSlow(b *PallocBits) PallocSum {
   664  	var start, most, end uint
   665  
   666  	const N = uint(len(b)) * 64
   667  	for start < N && (*pageBits)(b).get(start) == 0 {
   668  		start++
   669  	}
   670  	for end < N && (*pageBits)(b).get(N-end-1) == 0 {
   671  		end++
   672  	}
   673  	run := uint(0)
   674  	for i := uint(0); i < N; i++ {
   675  		if (*pageBits)(b).get(i) == 0 {
   676  			run++
   677  		} else {
   678  			run = 0
   679  		}
   680  		most = max(most, run)
   681  	}
   682  	return PackPallocSum(start, most, end)
   683  }
   684  
   685  // Expose non-trivial helpers for testing.
   686  func FindBitRange64(c uint64, n uint) uint { return findBitRange64(c, n) }
   687  
   688  // Given two PallocBits, returns a set of bit ranges where
   689  // they differ.
   690  func DiffPallocBits(a, b *PallocBits) []BitRange {
   691  	ba := (*pageBits)(a)
   692  	bb := (*pageBits)(b)
   693  
   694  	var d []BitRange
   695  	base, size := uint(0), uint(0)
   696  	for i := uint(0); i < uint(len(ba))*64; i++ {
   697  		if ba.get(i) != bb.get(i) {
   698  			if size == 0 {
   699  				base = i
   700  			}
   701  			size++
   702  		} else {
   703  			if size != 0 {
   704  				d = append(d, BitRange{base, size})
   705  			}
   706  			size = 0
   707  		}
   708  	}
   709  	if size != 0 {
   710  		d = append(d, BitRange{base, size})
   711  	}
   712  	return d
   713  }
   714  
   715  // StringifyPallocBits gets the bits in the bit range r from b,
   716  // and returns a string containing the bits as ASCII 0 and 1
   717  // characters.
   718  func StringifyPallocBits(b *PallocBits, r BitRange) string {
   719  	str := ""
   720  	for j := r.I; j < r.I+r.N; j++ {
   721  		if (*pageBits)(b).get(j) != 0 {
   722  			str += "1"
   723  		} else {
   724  			str += "0"
   725  		}
   726  	}
   727  	return str
   728  }
   729  
   730  // Expose pallocData for testing.
   731  type PallocData pallocData
   732  
   733  func (d *PallocData) FindScavengeCandidate(searchIdx uint, min, max uintptr) (uint, uint) {
   734  	return (*pallocData)(d).findScavengeCandidate(searchIdx, min, max)
   735  }
   736  func (d *PallocData) AllocRange(i, n uint) { (*pallocData)(d).allocRange(i, n) }
   737  func (d *PallocData) ScavengedSetRange(i, n uint) {
   738  	(*pallocData)(d).scavenged.setRange(i, n)
   739  }
   740  func (d *PallocData) PallocBits() *PallocBits {
   741  	return (*PallocBits)(&(*pallocData)(d).pallocBits)
   742  }
   743  func (d *PallocData) Scavenged() *PallocBits {
   744  	return (*PallocBits)(&(*pallocData)(d).scavenged)
   745  }
   746  
   747  // Expose fillAligned for testing.
   748  func FillAligned(x uint64, m uint) uint64 { return fillAligned(x, m) }
   749  
   750  // Expose pageCache for testing.
   751  type PageCache pageCache
   752  
   753  const PageCachePages = pageCachePages
   754  
   755  func NewPageCache(base uintptr, cache, scav uint64) PageCache {
   756  	return PageCache(pageCache{base: base, cache: cache, scav: scav})
   757  }
   758  func (c *PageCache) Empty() bool   { return (*pageCache)(c).empty() }
   759  func (c *PageCache) Base() uintptr { return (*pageCache)(c).base }
   760  func (c *PageCache) Cache() uint64 { return (*pageCache)(c).cache }
   761  func (c *PageCache) Scav() uint64  { return (*pageCache)(c).scav }
   762  func (c *PageCache) Alloc(npages uintptr) (uintptr, uintptr) {
   763  	return (*pageCache)(c).alloc(npages)
   764  }
   765  func (c *PageCache) Flush(s *PageAlloc) {
   766  	cp := (*pageCache)(c)
   767  	sp := (*pageAlloc)(s)
   768  
   769  	systemstack(func() {
   770  		// None of the tests need any higher-level locking, so we just
   771  		// take the lock internally.
   772  		lock(sp.mheapLock)
   773  		cp.flush(sp)
   774  		unlock(sp.mheapLock)
   775  	})
   776  }
   777  
   778  // Expose chunk index type.
   779  type ChunkIdx chunkIdx
   780  
   781  // Expose pageAlloc for testing. Note that because pageAlloc is
   782  // not in the heap, so is PageAlloc.
   783  type PageAlloc pageAlloc
   784  
   785  func (p *PageAlloc) Alloc(npages uintptr) (uintptr, uintptr) {
   786  	pp := (*pageAlloc)(p)
   787  
   788  	var addr, scav uintptr
   789  	systemstack(func() {
   790  		// None of the tests need any higher-level locking, so we just
   791  		// take the lock internally.
   792  		lock(pp.mheapLock)
   793  		addr, scav = pp.alloc(npages)
   794  		unlock(pp.mheapLock)
   795  	})
   796  	return addr, scav
   797  }
   798  func (p *PageAlloc) AllocToCache() PageCache {
   799  	pp := (*pageAlloc)(p)
   800  
   801  	var c PageCache
   802  	systemstack(func() {
   803  		// None of the tests need any higher-level locking, so we just
   804  		// take the lock internally.
   805  		lock(pp.mheapLock)
   806  		c = PageCache(pp.allocToCache())
   807  		unlock(pp.mheapLock)
   808  	})
   809  	return c
   810  }
   811  func (p *PageAlloc) Free(base, npages uintptr) {
   812  	pp := (*pageAlloc)(p)
   813  
   814  	systemstack(func() {
   815  		// None of the tests need any higher-level locking, so we just
   816  		// take the lock internally.
   817  		lock(pp.mheapLock)
   818  		pp.free(base, npages)
   819  		unlock(pp.mheapLock)
   820  	})
   821  }
   822  func (p *PageAlloc) Bounds() (ChunkIdx, ChunkIdx) {
   823  	return ChunkIdx((*pageAlloc)(p).start), ChunkIdx((*pageAlloc)(p).end)
   824  }
   825  func (p *PageAlloc) Scavenge(nbytes uintptr) (r uintptr) {
   826  	pp := (*pageAlloc)(p)
   827  	systemstack(func() {
   828  		r = pp.scavenge(nbytes, nil, true)
   829  	})
   830  	return
   831  }
   832  func (p *PageAlloc) InUse() []AddrRange {
   833  	ranges := make([]AddrRange, 0, len(p.inUse.ranges))
   834  	for _, r := range p.inUse.ranges {
   835  		ranges = append(ranges, AddrRange{r})
   836  	}
   837  	return ranges
   838  }
   839  
   840  // Returns nil if the PallocData's L2 is missing.
   841  func (p *PageAlloc) PallocData(i ChunkIdx) *PallocData {
   842  	ci := chunkIdx(i)
   843  	return (*PallocData)((*pageAlloc)(p).tryChunkOf(ci))
   844  }
   845  
   846  // AddrRange is a wrapper around addrRange for testing.
   847  type AddrRange struct {
   848  	addrRange
   849  }
   850  
   851  // MakeAddrRange creates a new address range.
   852  func MakeAddrRange(base, limit uintptr) AddrRange {
   853  	return AddrRange{makeAddrRange(base, limit)}
   854  }
   855  
   856  // Base returns the virtual base address of the address range.
   857  func (a AddrRange) Base() uintptr {
   858  	return a.addrRange.base.addr()
   859  }
   860  
   861  // Base returns the virtual address of the limit of the address range.
   862  func (a AddrRange) Limit() uintptr {
   863  	return a.addrRange.limit.addr()
   864  }
   865  
   866  // Equals returns true if the two address ranges are exactly equal.
   867  func (a AddrRange) Equals(b AddrRange) bool {
   868  	return a == b
   869  }
   870  
   871  // Size returns the size in bytes of the address range.
   872  func (a AddrRange) Size() uintptr {
   873  	return a.addrRange.size()
   874  }
   875  
   876  // testSysStat is the sysStat passed to test versions of various
   877  // runtime structures. We do actually have to keep track of this
   878  // because otherwise memstats.mappedReady won't actually line up
   879  // with other stats in the runtime during tests.
   880  var testSysStat = &memstats.other_sys
   881  
   882  // AddrRanges is a wrapper around addrRanges for testing.
   883  type AddrRanges struct {
   884  	addrRanges
   885  	mutable bool
   886  }
   887  
   888  // NewAddrRanges creates a new empty addrRanges.
   889  //
   890  // Note that this initializes addrRanges just like in the
   891  // runtime, so its memory is persistentalloc'd. Call this
   892  // function sparingly since the memory it allocates is
   893  // leaked.
   894  //
   895  // This AddrRanges is mutable, so we can test methods like
   896  // Add.
   897  func NewAddrRanges() AddrRanges {
   898  	r := addrRanges{}
   899  	r.init(testSysStat)
   900  	return AddrRanges{r, true}
   901  }
   902  
   903  // MakeAddrRanges creates a new addrRanges populated with
   904  // the ranges in a.
   905  //
   906  // The returned AddrRanges is immutable, so methods like
   907  // Add will fail.
   908  func MakeAddrRanges(a ...AddrRange) AddrRanges {
   909  	// Methods that manipulate the backing store of addrRanges.ranges should
   910  	// not be used on the result from this function (e.g. add) since they may
   911  	// trigger reallocation. That would normally be fine, except the new
   912  	// backing store won't come from the heap, but from persistentalloc, so
   913  	// we'll leak some memory implicitly.
   914  	ranges := make([]addrRange, 0, len(a))
   915  	total := uintptr(0)
   916  	for _, r := range a {
   917  		ranges = append(ranges, r.addrRange)
   918  		total += r.Size()
   919  	}
   920  	return AddrRanges{addrRanges{
   921  		ranges:     ranges,
   922  		totalBytes: total,
   923  		sysStat:    testSysStat,
   924  	}, false}
   925  }
   926  
   927  // Ranges returns a copy of the ranges described by the
   928  // addrRanges.
   929  func (a *AddrRanges) Ranges() []AddrRange {
   930  	result := make([]AddrRange, 0, len(a.addrRanges.ranges))
   931  	for _, r := range a.addrRanges.ranges {
   932  		result = append(result, AddrRange{r})
   933  	}
   934  	return result
   935  }
   936  
   937  // FindSucc returns the successor to base. See addrRanges.findSucc
   938  // for more details.
   939  func (a *AddrRanges) FindSucc(base uintptr) int {
   940  	return a.findSucc(base)
   941  }
   942  
   943  // Add adds a new AddrRange to the AddrRanges.
   944  //
   945  // The AddrRange must be mutable (i.e. created by NewAddrRanges),
   946  // otherwise this method will throw.
   947  func (a *AddrRanges) Add(r AddrRange) {
   948  	if !a.mutable {
   949  		throw("attempt to mutate immutable AddrRanges")
   950  	}
   951  	a.add(r.addrRange)
   952  }
   953  
   954  // TotalBytes returns the totalBytes field of the addrRanges.
   955  func (a *AddrRanges) TotalBytes() uintptr {
   956  	return a.addrRanges.totalBytes
   957  }
   958  
   959  // BitRange represents a range over a bitmap.
   960  type BitRange struct {
   961  	I, N uint // bit index and length in bits
   962  }
   963  
   964  // NewPageAlloc creates a new page allocator for testing and
   965  // initializes it with the scav and chunks maps. Each key in these maps
   966  // represents a chunk index and each value is a series of bit ranges to
   967  // set within each bitmap's chunk.
   968  //
   969  // The initialization of the pageAlloc preserves the invariant that if a
   970  // scavenged bit is set the alloc bit is necessarily unset, so some
   971  // of the bits described by scav may be cleared in the final bitmap if
   972  // ranges in chunks overlap with them.
   973  //
   974  // scav is optional, and if nil, the scavenged bitmap will be cleared
   975  // (as opposed to all 1s, which it usually is). Furthermore, every
   976  // chunk index in scav must appear in chunks; ones that do not are
   977  // ignored.
   978  func NewPageAlloc(chunks, scav map[ChunkIdx][]BitRange) *PageAlloc {
   979  	p := new(pageAlloc)
   980  
   981  	// We've got an entry, so initialize the pageAlloc.
   982  	p.init(new(mutex), testSysStat, true)
   983  	lockInit(p.mheapLock, lockRankMheap)
   984  	for i, init := range chunks {
   985  		addr := chunkBase(chunkIdx(i))
   986  
   987  		// Mark the chunk's existence in the pageAlloc.
   988  		systemstack(func() {
   989  			lock(p.mheapLock)
   990  			p.grow(addr, pallocChunkBytes)
   991  			unlock(p.mheapLock)
   992  		})
   993  
   994  		// Initialize the bitmap and update pageAlloc metadata.
   995  		ci := chunkIndex(addr)
   996  		chunk := p.chunkOf(ci)
   997  
   998  		// Clear all the scavenged bits which grow set.
   999  		chunk.scavenged.clearRange(0, pallocChunkPages)
  1000  
  1001  		// Simulate the allocation and subsequent free of all pages in
  1002  		// the chunk for the scavenge index. This sets the state equivalent
  1003  		// with all pages within the index being free.
  1004  		p.scav.index.alloc(ci, pallocChunkPages)
  1005  		p.scav.index.free(ci, 0, pallocChunkPages)
  1006  
  1007  		// Apply scavenge state if applicable.
  1008  		if scav != nil {
  1009  			if scvg, ok := scav[i]; ok {
  1010  				for _, s := range scvg {
  1011  					// Ignore the case of s.N == 0. setRange doesn't handle
  1012  					// it and it's a no-op anyway.
  1013  					if s.N != 0 {
  1014  						chunk.scavenged.setRange(s.I, s.N)
  1015  					}
  1016  				}
  1017  			}
  1018  		}
  1019  
  1020  		// Apply alloc state.
  1021  		for _, s := range init {
  1022  			// Ignore the case of s.N == 0. allocRange doesn't handle
  1023  			// it and it's a no-op anyway.
  1024  			if s.N != 0 {
  1025  				chunk.allocRange(s.I, s.N)
  1026  
  1027  				// Make sure the scavenge index is updated.
  1028  				p.scav.index.alloc(ci, s.N)
  1029  			}
  1030  		}
  1031  
  1032  		// Update heap metadata for the allocRange calls above.
  1033  		systemstack(func() {
  1034  			lock(p.mheapLock)
  1035  			p.update(addr, pallocChunkPages, false, false)
  1036  			unlock(p.mheapLock)
  1037  		})
  1038  	}
  1039  
  1040  	return (*PageAlloc)(p)
  1041  }
  1042  
  1043  // FreePageAlloc releases hard OS resources owned by the pageAlloc. Once this
  1044  // is called the pageAlloc may no longer be used. The object itself will be
  1045  // collected by the garbage collector once it is no longer live.
  1046  func FreePageAlloc(pp *PageAlloc) {
  1047  	p := (*pageAlloc)(pp)
  1048  
  1049  	// Free all the mapped space for the summary levels.
  1050  	if pageAlloc64Bit != 0 {
  1051  		for l := 0; l < summaryLevels; l++ {
  1052  			sysFreeOS(unsafe.Pointer(&p.summary[l][0]), uintptr(cap(p.summary[l]))*pallocSumBytes)
  1053  		}
  1054  	} else {
  1055  		resSize := uintptr(0)
  1056  		for _, s := range p.summary {
  1057  			resSize += uintptr(cap(s)) * pallocSumBytes
  1058  		}
  1059  		sysFreeOS(unsafe.Pointer(&p.summary[0][0]), alignUp(resSize, physPageSize))
  1060  	}
  1061  
  1062  	// Free extra data structures.
  1063  	sysFreeOS(unsafe.Pointer(&p.scav.index.chunks[0]), uintptr(cap(p.scav.index.chunks))*unsafe.Sizeof(atomicScavChunkData{}))
  1064  
  1065  	// Subtract back out whatever we mapped for the summaries.
  1066  	// sysUsed adds to p.sysStat and memstats.mappedReady no matter what
  1067  	// (and in anger should actually be accounted for), and there's no other
  1068  	// way to figure out how much we actually mapped.
  1069  	gcController.mappedReady.Add(-int64(p.summaryMappedReady))
  1070  	testSysStat.add(-int64(p.summaryMappedReady))
  1071  
  1072  	// Free the mapped space for chunks.
  1073  	for i := range p.chunks {
  1074  		if x := p.chunks[i]; x != nil {
  1075  			p.chunks[i] = nil
  1076  			// This memory comes from sysAlloc and will always be page-aligned.
  1077  			sysFree(unsafe.Pointer(x), unsafe.Sizeof(*p.chunks[0]), testSysStat)
  1078  		}
  1079  	}
  1080  }
  1081  
  1082  // BaseChunkIdx is a convenient chunkIdx value which works on both
  1083  // 64 bit and 32 bit platforms, allowing the tests to share code
  1084  // between the two.
  1085  //
  1086  // This should not be higher than 0x100*pallocChunkBytes to support
  1087  // mips and mipsle, which only have 31-bit address spaces.
  1088  var BaseChunkIdx = func() ChunkIdx {
  1089  	var prefix uintptr
  1090  	if pageAlloc64Bit != 0 {
  1091  		prefix = 0xc000
  1092  	} else {
  1093  		prefix = 0x100
  1094  	}
  1095  	baseAddr := prefix * pallocChunkBytes
  1096  	if goos.IsAix != 0 {
  1097  		baseAddr += arenaBaseOffset
  1098  	}
  1099  	return ChunkIdx(chunkIndex(baseAddr))
  1100  }()
  1101  
  1102  // PageBase returns an address given a chunk index and a page index
  1103  // relative to that chunk.
  1104  func PageBase(c ChunkIdx, pageIdx uint) uintptr {
  1105  	return chunkBase(chunkIdx(c)) + uintptr(pageIdx)*pageSize
  1106  }
  1107  
  1108  type BitsMismatch struct {
  1109  	Base      uintptr
  1110  	Got, Want uint64
  1111  }
  1112  
  1113  func CheckScavengedBitsCleared(mismatches []BitsMismatch) (n int, ok bool) {
  1114  	ok = true
  1115  
  1116  	// Run on the system stack to avoid stack growth allocation.
  1117  	systemstack(func() {
  1118  		getg().m.mallocing++
  1119  
  1120  		// Lock so that we can safely access the bitmap.
  1121  		lock(&mheap_.lock)
  1122  	chunkLoop:
  1123  		for i := mheap_.pages.start; i < mheap_.pages.end; i++ {
  1124  			chunk := mheap_.pages.tryChunkOf(i)
  1125  			if chunk == nil {
  1126  				continue
  1127  			}
  1128  			for j := 0; j < pallocChunkPages/64; j++ {
  1129  				// Run over each 64-bit bitmap section and ensure
  1130  				// scavenged is being cleared properly on allocation.
  1131  				// If a used bit and scavenged bit are both set, that's
  1132  				// an error, and could indicate a larger problem, or
  1133  				// an accounting problem.
  1134  				want := chunk.scavenged[j] &^ chunk.pallocBits[j]
  1135  				got := chunk.scavenged[j]
  1136  				if want != got {
  1137  					ok = false
  1138  					if n >= len(mismatches) {
  1139  						break chunkLoop
  1140  					}
  1141  					mismatches[n] = BitsMismatch{
  1142  						Base: chunkBase(i) + uintptr(j)*64*pageSize,
  1143  						Got:  got,
  1144  						Want: want,
  1145  					}
  1146  					n++
  1147  				}
  1148  			}
  1149  		}
  1150  		unlock(&mheap_.lock)
  1151  
  1152  		getg().m.mallocing--
  1153  	})
  1154  	return
  1155  }
  1156  
  1157  func PageCachePagesLeaked() (leaked uintptr) {
  1158  	stw := stopTheWorld(stwForTestPageCachePagesLeaked)
  1159  
  1160  	// Walk over destroyed Ps and look for unflushed caches.
  1161  	deadp := allp[len(allp):cap(allp)]
  1162  	for _, p := range deadp {
  1163  		// Since we're going past len(allp) we may see nil Ps.
  1164  		// Just ignore them.
  1165  		if p != nil {
  1166  			leaked += uintptr(sys.OnesCount64(p.pcache.cache))
  1167  		}
  1168  	}
  1169  
  1170  	startTheWorld(stw)
  1171  	return
  1172  }
  1173  
  1174  var ProcYield = procyield
  1175  var OSYield = osyield
  1176  
  1177  type Mutex = mutex
  1178  
  1179  var Lock = lock
  1180  var Unlock = unlock
  1181  
  1182  var MutexContended = mutexContended
  1183  
  1184  func SemRootLock(addr *uint32) *mutex {
  1185  	root := semtable.rootFor(addr)
  1186  	return &root.lock
  1187  }
  1188  
  1189  var Semacquire = semacquire
  1190  var Semrelease1 = semrelease1
  1191  
  1192  func SemNwait(addr *uint32) uint32 {
  1193  	root := semtable.rootFor(addr)
  1194  	return root.nwait.Load()
  1195  }
  1196  
  1197  const SemTableSize = semTabSize
  1198  
  1199  // SemTable is a wrapper around semTable exported for testing.
  1200  type SemTable struct {
  1201  	semTable
  1202  }
  1203  
  1204  // Enqueue simulates enqueuing a waiter for a semaphore (or lock) at addr.
  1205  func (t *SemTable) Enqueue(addr *uint32) {
  1206  	s := acquireSudog()
  1207  	s.releasetime = 0
  1208  	s.acquiretime = 0
  1209  	s.ticket = 0
  1210  	t.semTable.rootFor(addr).queue(addr, s, false)
  1211  }
  1212  
  1213  // Dequeue simulates dequeuing a waiter for a semaphore (or lock) at addr.
  1214  //
  1215  // Returns true if there actually was a waiter to be dequeued.
  1216  func (t *SemTable) Dequeue(addr *uint32) bool {
  1217  	s, _, _ := t.semTable.rootFor(addr).dequeue(addr)
  1218  	if s != nil {
  1219  		releaseSudog(s)
  1220  		return true
  1221  	}
  1222  	return false
  1223  }
  1224  
  1225  // mspan wrapper for testing.
  1226  type MSpan mspan
  1227  
  1228  // Allocate an mspan for testing.
  1229  func AllocMSpan() *MSpan {
  1230  	var s *mspan
  1231  	systemstack(func() {
  1232  		lock(&mheap_.lock)
  1233  		s = (*mspan)(mheap_.spanalloc.alloc())
  1234  		unlock(&mheap_.lock)
  1235  	})
  1236  	return (*MSpan)(s)
  1237  }
  1238  
  1239  // Free an allocated mspan.
  1240  func FreeMSpan(s *MSpan) {
  1241  	systemstack(func() {
  1242  		lock(&mheap_.lock)
  1243  		mheap_.spanalloc.free(unsafe.Pointer(s))
  1244  		unlock(&mheap_.lock)
  1245  	})
  1246  }
  1247  
  1248  func MSpanCountAlloc(ms *MSpan, bits []byte) int {
  1249  	s := (*mspan)(ms)
  1250  	s.nelems = uint16(len(bits) * 8)
  1251  	s.gcmarkBits = (*gcBits)(unsafe.Pointer(&bits[0]))
  1252  	result := s.countAlloc()
  1253  	s.gcmarkBits = nil
  1254  	return result
  1255  }
  1256  
  1257  const (
  1258  	TimeHistSubBucketBits = timeHistSubBucketBits
  1259  	TimeHistNumSubBuckets = timeHistNumSubBuckets
  1260  	TimeHistNumBuckets    = timeHistNumBuckets
  1261  	TimeHistMinBucketBits = timeHistMinBucketBits
  1262  	TimeHistMaxBucketBits = timeHistMaxBucketBits
  1263  )
  1264  
  1265  type TimeHistogram timeHistogram
  1266  
  1267  // Count returns the counts for the given bucket, subBucket indices.
  1268  // Returns true if the bucket was valid, otherwise returns the counts
  1269  // for the overflow bucket if bucket > 0 or the underflow bucket if
  1270  // bucket < 0, and false.
  1271  func (th *TimeHistogram) Count(bucket, subBucket int) (uint64, bool) {
  1272  	t := (*timeHistogram)(th)
  1273  	if bucket < 0 {
  1274  		return t.underflow.Load(), false
  1275  	}
  1276  	i := bucket*TimeHistNumSubBuckets + subBucket
  1277  	if i >= len(t.counts) {
  1278  		return t.overflow.Load(), false
  1279  	}
  1280  	return t.counts[i].Load(), true
  1281  }
  1282  
  1283  func (th *TimeHistogram) Record(duration int64) {
  1284  	(*timeHistogram)(th).record(duration)
  1285  }
  1286  
  1287  var TimeHistogramMetricsBuckets = timeHistogramMetricsBuckets
  1288  
  1289  func SetIntArgRegs(a int) int {
  1290  	lock(&finlock)
  1291  	old := intArgRegs
  1292  	if a >= 0 {
  1293  		intArgRegs = a
  1294  	}
  1295  	unlock(&finlock)
  1296  	return old
  1297  }
  1298  
  1299  func FinalizerGAsleep() bool {
  1300  	return fingStatus.Load()&fingWait != 0
  1301  }
  1302  
  1303  // For GCTestMoveStackOnNextCall, it's important not to introduce an
  1304  // extra layer of call, since then there's a return before the "real"
  1305  // next call.
  1306  var GCTestMoveStackOnNextCall = gcTestMoveStackOnNextCall
  1307  
  1308  // For GCTestIsReachable, it's important that we do this as a call so
  1309  // escape analysis can see through it.
  1310  func GCTestIsReachable(ptrs ...unsafe.Pointer) (mask uint64) {
  1311  	return gcTestIsReachable(ptrs...)
  1312  }
  1313  
  1314  // For GCTestPointerClass, it's important that we do this as a call so
  1315  // escape analysis can see through it.
  1316  //
  1317  // This is nosplit because gcTestPointerClass is.
  1318  //
  1319  //go:nosplit
  1320  func GCTestPointerClass(p unsafe.Pointer) string {
  1321  	return gcTestPointerClass(p)
  1322  }
  1323  
  1324  const Raceenabled = raceenabled
  1325  
  1326  const (
  1327  	GCBackgroundUtilization            = gcBackgroundUtilization
  1328  	GCGoalUtilization                  = gcGoalUtilization
  1329  	DefaultHeapMinimum                 = defaultHeapMinimum
  1330  	MemoryLimitHeapGoalHeadroomPercent = memoryLimitHeapGoalHeadroomPercent
  1331  	MemoryLimitMinHeapGoalHeadroom     = memoryLimitMinHeapGoalHeadroom
  1332  )
  1333  
  1334  type GCController struct {
  1335  	gcControllerState
  1336  }
  1337  
  1338  func NewGCController(gcPercent int, memoryLimit int64) *GCController {
  1339  	// Force the controller to escape. We're going to
  1340  	// do 64-bit atomics on it, and if it gets stack-allocated
  1341  	// on a 32-bit architecture, it may get allocated unaligned
  1342  	// space.
  1343  	g := Escape(new(GCController))
  1344  	g.gcControllerState.test = true // Mark it as a test copy.
  1345  	g.init(int32(gcPercent), memoryLimit)
  1346  	return g
  1347  }
  1348  
  1349  func (c *GCController) StartCycle(stackSize, globalsSize uint64, scannableFrac float64, gomaxprocs int) {
  1350  	trigger, _ := c.trigger()
  1351  	if c.heapMarked > trigger {
  1352  		trigger = c.heapMarked
  1353  	}
  1354  	c.maxStackScan.Store(stackSize)
  1355  	c.globalsScan.Store(globalsSize)
  1356  	c.heapLive.Store(trigger)
  1357  	c.heapScan.Add(int64(float64(trigger-c.heapMarked) * scannableFrac))
  1358  	c.startCycle(0, gomaxprocs, gcTrigger{kind: gcTriggerHeap})
  1359  }
  1360  
  1361  func (c *GCController) AssistWorkPerByte() float64 {
  1362  	return c.assistWorkPerByte.Load()
  1363  }
  1364  
  1365  func (c *GCController) HeapGoal() uint64 {
  1366  	return c.heapGoal()
  1367  }
  1368  
  1369  func (c *GCController) HeapLive() uint64 {
  1370  	return c.heapLive.Load()
  1371  }
  1372  
  1373  func (c *GCController) HeapMarked() uint64 {
  1374  	return c.heapMarked
  1375  }
  1376  
  1377  func (c *GCController) Triggered() uint64 {
  1378  	return c.triggered
  1379  }
  1380  
  1381  type GCControllerReviseDelta struct {
  1382  	HeapLive        int64
  1383  	HeapScan        int64
  1384  	HeapScanWork    int64
  1385  	StackScanWork   int64
  1386  	GlobalsScanWork int64
  1387  }
  1388  
  1389  func (c *GCController) Revise(d GCControllerReviseDelta) {
  1390  	c.heapLive.Add(d.HeapLive)
  1391  	c.heapScan.Add(d.HeapScan)
  1392  	c.heapScanWork.Add(d.HeapScanWork)
  1393  	c.stackScanWork.Add(d.StackScanWork)
  1394  	c.globalsScanWork.Add(d.GlobalsScanWork)
  1395  	c.revise()
  1396  }
  1397  
  1398  func (c *GCController) EndCycle(bytesMarked uint64, assistTime, elapsed int64, gomaxprocs int) {
  1399  	c.assistTime.Store(assistTime)
  1400  	c.endCycle(elapsed, gomaxprocs, false)
  1401  	c.resetLive(bytesMarked)
  1402  	c.commit(false)
  1403  }
  1404  
  1405  func (c *GCController) AddIdleMarkWorker() bool {
  1406  	return c.addIdleMarkWorker()
  1407  }
  1408  
  1409  func (c *GCController) NeedIdleMarkWorker() bool {
  1410  	return c.needIdleMarkWorker()
  1411  }
  1412  
  1413  func (c *GCController) RemoveIdleMarkWorker() {
  1414  	c.removeIdleMarkWorker()
  1415  }
  1416  
  1417  func (c *GCController) SetMaxIdleMarkWorkers(max int32) {
  1418  	c.setMaxIdleMarkWorkers(max)
  1419  }
  1420  
  1421  var alwaysFalse bool
  1422  var escapeSink any
  1423  
  1424  func Escape[T any](x T) T {
  1425  	if alwaysFalse {
  1426  		escapeSink = x
  1427  	}
  1428  	return x
  1429  }
  1430  
  1431  // Acquirem blocks preemption.
  1432  func Acquirem() {
  1433  	acquirem()
  1434  }
  1435  
  1436  func Releasem() {
  1437  	releasem(getg().m)
  1438  }
  1439  
  1440  var Timediv = timediv
  1441  
  1442  type PIController struct {
  1443  	piController
  1444  }
  1445  
  1446  func NewPIController(kp, ti, tt, min, max float64) *PIController {
  1447  	return &PIController{piController{
  1448  		kp:  kp,
  1449  		ti:  ti,
  1450  		tt:  tt,
  1451  		min: min,
  1452  		max: max,
  1453  	}}
  1454  }
  1455  
  1456  func (c *PIController) Next(input, setpoint, period float64) (float64, bool) {
  1457  	return c.piController.next(input, setpoint, period)
  1458  }
  1459  
  1460  const (
  1461  	CapacityPerProc          = capacityPerProc
  1462  	GCCPULimiterUpdatePeriod = gcCPULimiterUpdatePeriod
  1463  )
  1464  
  1465  type GCCPULimiter struct {
  1466  	limiter gcCPULimiterState
  1467  }
  1468  
  1469  func NewGCCPULimiter(now int64, gomaxprocs int32) *GCCPULimiter {
  1470  	// Force the controller to escape. We're going to
  1471  	// do 64-bit atomics on it, and if it gets stack-allocated
  1472  	// on a 32-bit architecture, it may get allocated unaligned
  1473  	// space.
  1474  	l := Escape(new(GCCPULimiter))
  1475  	l.limiter.test = true
  1476  	l.limiter.resetCapacity(now, gomaxprocs)
  1477  	return l
  1478  }
  1479  
  1480  func (l *GCCPULimiter) Fill() uint64 {
  1481  	return l.limiter.bucket.fill
  1482  }
  1483  
  1484  func (l *GCCPULimiter) Capacity() uint64 {
  1485  	return l.limiter.bucket.capacity
  1486  }
  1487  
  1488  func (l *GCCPULimiter) Overflow() uint64 {
  1489  	return l.limiter.overflow
  1490  }
  1491  
  1492  func (l *GCCPULimiter) Limiting() bool {
  1493  	return l.limiter.limiting()
  1494  }
  1495  
  1496  func (l *GCCPULimiter) NeedUpdate(now int64) bool {
  1497  	return l.limiter.needUpdate(now)
  1498  }
  1499  
  1500  func (l *GCCPULimiter) StartGCTransition(enableGC bool, now int64) {
  1501  	l.limiter.startGCTransition(enableGC, now)
  1502  }
  1503  
  1504  func (l *GCCPULimiter) FinishGCTransition(now int64) {
  1505  	l.limiter.finishGCTransition(now)
  1506  }
  1507  
  1508  func (l *GCCPULimiter) Update(now int64) {
  1509  	l.limiter.update(now)
  1510  }
  1511  
  1512  func (l *GCCPULimiter) AddAssistTime(t int64) {
  1513  	l.limiter.addAssistTime(t)
  1514  }
  1515  
  1516  func (l *GCCPULimiter) ResetCapacity(now int64, nprocs int32) {
  1517  	l.limiter.resetCapacity(now, nprocs)
  1518  }
  1519  
  1520  const ScavengePercent = scavengePercent
  1521  
  1522  type Scavenger struct {
  1523  	Sleep      func(int64) int64
  1524  	Scavenge   func(uintptr) (uintptr, int64)
  1525  	ShouldStop func() bool
  1526  	GoMaxProcs func() int32
  1527  
  1528  	released  atomic.Uintptr
  1529  	scavenger scavengerState
  1530  	stop      chan<- struct{}
  1531  	done      <-chan struct{}
  1532  }
  1533  
  1534  func (s *Scavenger) Start() {
  1535  	if s.Sleep == nil || s.Scavenge == nil || s.ShouldStop == nil || s.GoMaxProcs == nil {
  1536  		panic("must populate all stubs")
  1537  	}
  1538  
  1539  	// Install hooks.
  1540  	s.scavenger.sleepStub = s.Sleep
  1541  	s.scavenger.scavenge = s.Scavenge
  1542  	s.scavenger.shouldStop = s.ShouldStop
  1543  	s.scavenger.gomaxprocs = s.GoMaxProcs
  1544  
  1545  	// Start up scavenger goroutine, and wait for it to be ready.
  1546  	stop := make(chan struct{})
  1547  	s.stop = stop
  1548  	done := make(chan struct{})
  1549  	s.done = done
  1550  	go func() {
  1551  		// This should match bgscavenge, loosely.
  1552  		s.scavenger.init()
  1553  		s.scavenger.park()
  1554  		for {
  1555  			select {
  1556  			case <-stop:
  1557  				close(done)
  1558  				return
  1559  			default:
  1560  			}
  1561  			released, workTime := s.scavenger.run()
  1562  			if released == 0 {
  1563  				s.scavenger.park()
  1564  				continue
  1565  			}
  1566  			s.released.Add(released)
  1567  			s.scavenger.sleep(workTime)
  1568  		}
  1569  	}()
  1570  	if !s.BlockUntilParked(1e9 /* 1 second */) {
  1571  		panic("timed out waiting for scavenger to get ready")
  1572  	}
  1573  }
  1574  
  1575  // BlockUntilParked blocks until the scavenger parks, or until
  1576  // timeout is exceeded. Returns true if the scavenger parked.
  1577  //
  1578  // Note that in testing, parked means something slightly different.
  1579  // In anger, the scavenger parks to sleep, too, but in testing,
  1580  // it only parks when it actually has no work to do.
  1581  func (s *Scavenger) BlockUntilParked(timeout int64) bool {
  1582  	// Just spin, waiting for it to park.
  1583  	//
  1584  	// The actual parking process is racy with respect to
  1585  	// wakeups, which is fine, but for testing we need something
  1586  	// a bit more robust.
  1587  	start := nanotime()
  1588  	for nanotime()-start < timeout {
  1589  		lock(&s.scavenger.lock)
  1590  		parked := s.scavenger.parked
  1591  		unlock(&s.scavenger.lock)
  1592  		if parked {
  1593  			return true
  1594  		}
  1595  		Gosched()
  1596  	}
  1597  	return false
  1598  }
  1599  
  1600  // Released returns how many bytes the scavenger released.
  1601  func (s *Scavenger) Released() uintptr {
  1602  	return s.released.Load()
  1603  }
  1604  
  1605  // Wake wakes up a parked scavenger to keep running.
  1606  func (s *Scavenger) Wake() {
  1607  	s.scavenger.wake()
  1608  }
  1609  
  1610  // Stop cleans up the scavenger's resources. The scavenger
  1611  // must be parked for this to work.
  1612  func (s *Scavenger) Stop() {
  1613  	lock(&s.scavenger.lock)
  1614  	parked := s.scavenger.parked
  1615  	unlock(&s.scavenger.lock)
  1616  	if !parked {
  1617  		panic("tried to clean up scavenger that is not parked")
  1618  	}
  1619  	close(s.stop)
  1620  	s.Wake()
  1621  	<-s.done
  1622  }
  1623  
  1624  type ScavengeIndex struct {
  1625  	i scavengeIndex
  1626  }
  1627  
  1628  func NewScavengeIndex(min, max ChunkIdx) *ScavengeIndex {
  1629  	s := new(ScavengeIndex)
  1630  	// This is a bit lazy but we easily guarantee we'll be able
  1631  	// to reference all the relevant chunks. The worst-case
  1632  	// memory usage here is 512 MiB, but tests generally use
  1633  	// small offsets from BaseChunkIdx, which results in ~100s
  1634  	// of KiB in memory use.
  1635  	//
  1636  	// This may still be worth making better, at least by sharing
  1637  	// this fairly large array across calls with a sync.Pool or
  1638  	// something. Currently, when the tests are run serially,
  1639  	// it takes around 0.5s. Not all that much, but if we have
  1640  	// a lot of tests like this it could add up.
  1641  	s.i.chunks = make([]atomicScavChunkData, max)
  1642  	s.i.min.Store(uintptr(min))
  1643  	s.i.max.Store(uintptr(max))
  1644  	s.i.minHeapIdx.Store(uintptr(min))
  1645  	s.i.test = true
  1646  	return s
  1647  }
  1648  
  1649  func (s *ScavengeIndex) Find(force bool) (ChunkIdx, uint) {
  1650  	ci, off := s.i.find(force)
  1651  	return ChunkIdx(ci), off
  1652  }
  1653  
  1654  func (s *ScavengeIndex) AllocRange(base, limit uintptr) {
  1655  	sc, ec := chunkIndex(base), chunkIndex(limit-1)
  1656  	si, ei := chunkPageIndex(base), chunkPageIndex(limit-1)
  1657  
  1658  	if sc == ec {
  1659  		// The range doesn't cross any chunk boundaries.
  1660  		s.i.alloc(sc, ei+1-si)
  1661  	} else {
  1662  		// The range crosses at least one chunk boundary.
  1663  		s.i.alloc(sc, pallocChunkPages-si)
  1664  		for c := sc + 1; c < ec; c++ {
  1665  			s.i.alloc(c, pallocChunkPages)
  1666  		}
  1667  		s.i.alloc(ec, ei+1)
  1668  	}
  1669  }
  1670  
  1671  func (s *ScavengeIndex) FreeRange(base, limit uintptr) {
  1672  	sc, ec := chunkIndex(base), chunkIndex(limit-1)
  1673  	si, ei := chunkPageIndex(base), chunkPageIndex(limit-1)
  1674  
  1675  	if sc == ec {
  1676  		// The range doesn't cross any chunk boundaries.
  1677  		s.i.free(sc, si, ei+1-si)
  1678  	} else {
  1679  		// The range crosses at least one chunk boundary.
  1680  		s.i.free(sc, si, pallocChunkPages-si)
  1681  		for c := sc + 1; c < ec; c++ {
  1682  			s.i.free(c, 0, pallocChunkPages)
  1683  		}
  1684  		s.i.free(ec, 0, ei+1)
  1685  	}
  1686  }
  1687  
  1688  func (s *ScavengeIndex) ResetSearchAddrs() {
  1689  	for _, a := range []*atomicOffAddr{&s.i.searchAddrBg, &s.i.searchAddrForce} {
  1690  		addr, marked := a.Load()
  1691  		if marked {
  1692  			a.StoreUnmark(addr, addr)
  1693  		}
  1694  		a.Clear()
  1695  	}
  1696  	s.i.freeHWM = minOffAddr
  1697  }
  1698  
  1699  func (s *ScavengeIndex) NextGen() {
  1700  	s.i.nextGen()
  1701  }
  1702  
  1703  func (s *ScavengeIndex) SetEmpty(ci ChunkIdx) {
  1704  	s.i.setEmpty(chunkIdx(ci))
  1705  }
  1706  
  1707  func CheckPackScavChunkData(gen uint32, inUse, lastInUse uint16, flags uint8) bool {
  1708  	sc0 := scavChunkData{
  1709  		gen:            gen,
  1710  		inUse:          inUse,
  1711  		lastInUse:      lastInUse,
  1712  		scavChunkFlags: scavChunkFlags(flags),
  1713  	}
  1714  	scp := sc0.pack()
  1715  	sc1 := unpackScavChunkData(scp)
  1716  	return sc0 == sc1
  1717  }
  1718  
  1719  const GTrackingPeriod = gTrackingPeriod
  1720  
  1721  var ZeroBase = unsafe.Pointer(&zerobase)
  1722  
  1723  const UserArenaChunkBytes = userArenaChunkBytes
  1724  
  1725  type UserArena struct {
  1726  	arena *userArena
  1727  }
  1728  
  1729  func NewUserArena() *UserArena {
  1730  	return &UserArena{newUserArena()}
  1731  }
  1732  
  1733  func (a *UserArena) New(out *any) {
  1734  	i := efaceOf(out)
  1735  	typ := i._type
  1736  	if typ.Kind_&abi.KindMask != abi.Pointer {
  1737  		panic("new result of non-ptr type")
  1738  	}
  1739  	typ = (*ptrtype)(unsafe.Pointer(typ)).Elem
  1740  	i.data = a.arena.new(typ)
  1741  }
  1742  
  1743  func (a *UserArena) Slice(sl any, cap int) {
  1744  	a.arena.slice(sl, cap)
  1745  }
  1746  
  1747  func (a *UserArena) Free() {
  1748  	a.arena.free()
  1749  }
  1750  
  1751  func GlobalWaitingArenaChunks() int {
  1752  	n := 0
  1753  	systemstack(func() {
  1754  		lock(&mheap_.lock)
  1755  		for s := mheap_.userArena.quarantineList.first; s != nil; s = s.next {
  1756  			n++
  1757  		}
  1758  		unlock(&mheap_.lock)
  1759  	})
  1760  	return n
  1761  }
  1762  
  1763  func UserArenaClone[T any](s T) T {
  1764  	return arena_heapify(s).(T)
  1765  }
  1766  
  1767  var AlignUp = alignUp
  1768  
  1769  func BlockUntilEmptyFinalizerQueue(timeout int64) bool {
  1770  	return blockUntilEmptyFinalizerQueue(timeout)
  1771  }
  1772  
  1773  func FrameStartLine(f *Frame) int {
  1774  	return f.startLine
  1775  }
  1776  
  1777  // PersistentAlloc allocates some memory that lives outside the Go heap.
  1778  // This memory will never be freed; use sparingly.
  1779  func PersistentAlloc(n uintptr) unsafe.Pointer {
  1780  	return persistentalloc(n, 0, &memstats.other_sys)
  1781  }
  1782  
  1783  // FPCallers works like Callers and uses frame pointer unwinding to populate
  1784  // pcBuf with the return addresses of the physical frames on the stack.
  1785  func FPCallers(pcBuf []uintptr) int {
  1786  	return fpTracebackPCs(unsafe.Pointer(getfp()), pcBuf)
  1787  }
  1788  
  1789  const FramePointerEnabled = framepointer_enabled
  1790  
  1791  var (
  1792  	IsPinned      = isPinned
  1793  	GetPinCounter = pinnerGetPinCounter
  1794  )
  1795  
  1796  func SetPinnerLeakPanic(f func()) {
  1797  	pinnerLeakPanic = f
  1798  }
  1799  func GetPinnerLeakPanic() func() {
  1800  	return pinnerLeakPanic
  1801  }
  1802  
  1803  var testUintptr uintptr
  1804  
  1805  func MyGenericFunc[T any]() {
  1806  	systemstack(func() {
  1807  		testUintptr = 4
  1808  	})
  1809  }
  1810  
  1811  func UnsafePoint(pc uintptr) bool {
  1812  	fi := findfunc(pc)
  1813  	v := pcdatavalue(fi, abi.PCDATA_UnsafePoint, pc)
  1814  	switch v {
  1815  	case abi.UnsafePointUnsafe:
  1816  		return true
  1817  	case abi.UnsafePointSafe:
  1818  		return false
  1819  	case abi.UnsafePointRestart1, abi.UnsafePointRestart2, abi.UnsafePointRestartAtEntry:
  1820  		// These are all interruptible, they just encode a nonstandard
  1821  		// way of recovering when interrupted.
  1822  		return false
  1823  	default:
  1824  		var buf [20]byte
  1825  		panic("invalid unsafe point code " + string(itoa(buf[:], uint64(v))))
  1826  	}
  1827  }
  1828  
  1829  type TraceMap struct {
  1830  	traceMap
  1831  }
  1832  
  1833  func (m *TraceMap) PutString(s string) (uint64, bool) {
  1834  	return m.traceMap.put(unsafe.Pointer(unsafe.StringData(s)), uintptr(len(s)))
  1835  }
  1836  
  1837  func (m *TraceMap) Reset() {
  1838  	m.traceMap.reset()
  1839  }
  1840  
  1841  func SetSpinInGCMarkDone(spin bool) {
  1842  	gcDebugMarkDone.spinAfterRaggedBarrier.Store(spin)
  1843  }
  1844  
  1845  func GCMarkDoneRestarted() bool {
  1846  	// Only read this outside of the GC. If we're running during a GC, just report false.
  1847  	mp := acquirem()
  1848  	if gcphase != _GCoff {
  1849  		releasem(mp)
  1850  		return false
  1851  	}
  1852  	restarted := gcDebugMarkDone.restartedDueTo27993
  1853  	releasem(mp)
  1854  	return restarted
  1855  }
  1856  
  1857  func GCMarkDoneResetRestartFlag() {
  1858  	mp := acquirem()
  1859  	for gcphase != _GCoff {
  1860  		releasem(mp)
  1861  		Gosched()
  1862  		mp = acquirem()
  1863  	}
  1864  	gcDebugMarkDone.restartedDueTo27993 = false
  1865  	releasem(mp)
  1866  }
  1867  
  1868  type BitCursor struct {
  1869  	b bitCursor
  1870  }
  1871  
  1872  func NewBitCursor(buf *byte) BitCursor {
  1873  	return BitCursor{b: bitCursor{ptr: buf, n: 0}}
  1874  }
  1875  
  1876  func (b BitCursor) Write(data *byte, cnt uintptr) {
  1877  	b.b.write(data, cnt)
  1878  }
  1879  func (b BitCursor) Offset(cnt uintptr) BitCursor {
  1880  	return BitCursor{b: b.b.offset(cnt)}
  1881  }
  1882  

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