File: jsutil.cpp

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/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 4 -*-
 * vim: set ts=8 sts=4 et sw=4 tw=99:
 * This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */

/* Various JS utility functions. */

#include "jsutil.h"

#include "mozilla/Assertions.h"
#include "mozilla/MathAlgorithms.h"
#include "mozilla/Maybe.h"
#include "mozilla/PodOperations.h"
#include "mozilla/ThreadLocal.h"

#include <stdio.h>

#include "jstypes.h"

#include "js/Utility.h"
#include "util/Windows.h"
#include "vm/HelperThreads.h"

using namespace js;

using mozilla::CeilingLog2Size;
using mozilla::PodArrayZero;

#if defined(DEBUG) || defined(JS_OOM_BREAKPOINT)
/* For OOM testing functionality in Utility.h. */
namespace js {

mozilla::Atomic<AutoEnterOOMUnsafeRegion*> AutoEnterOOMUnsafeRegion::owner_;

namespace oom {

JS_PUBLIC_DATA uint32_t targetThread = 0;
MOZ_THREAD_LOCAL(uint32_t) threadType;
JS_PUBLIC_DATA uint64_t maxAllocations = UINT64_MAX;
JS_PUBLIC_DATA uint64_t counter = 0;
JS_PUBLIC_DATA bool failAlways = true;

JS_PUBLIC_DATA uint32_t stackTargetThread = 0;
JS_PUBLIC_DATA uint64_t maxStackChecks = UINT64_MAX;
JS_PUBLIC_DATA uint64_t stackCheckCounter = 0;
JS_PUBLIC_DATA bool stackCheckFailAlways = true;

JS_PUBLIC_DATA uint32_t interruptTargetThread = 0;
JS_PUBLIC_DATA uint64_t maxInterruptChecks = UINT64_MAX;
JS_PUBLIC_DATA uint64_t interruptCheckCounter = 0;
JS_PUBLIC_DATA bool interruptCheckFailAlways = true;

bool InitThreadType(void) { return threadType.init(); }

void SetThreadType(ThreadType type) { threadType.set(type); }

uint32_t GetThreadType(void) { return threadType.get(); }

static inline bool IsHelperThreadType(uint32_t thread) {
  return thread != THREAD_TYPE_NONE && thread != THREAD_TYPE_COOPERATING;
}

void SimulateOOMAfter(uint64_t allocations, uint32_t thread, bool always) {
  Maybe<AutoLockHelperThreadState> lock;
  if (IsHelperThreadType(targetThread) || IsHelperThreadType(thread)) {
    lock.emplace();
    HelperThreadState().waitForAllThreadsLocked(lock.ref());
  }

  MOZ_ASSERT(counter + allocations > counter);
  MOZ_ASSERT(thread > js::THREAD_TYPE_NONE && thread < js::THREAD_TYPE_MAX);
  targetThread = thread;
  maxAllocations = counter + allocations;
  failAlways = always;
}

void ResetSimulatedOOM() {
  Maybe<AutoLockHelperThreadState> lock;
  if (IsHelperThreadType(targetThread)) {
    lock.emplace();
    HelperThreadState().waitForAllThreadsLocked(lock.ref());
  }

  targetThread = THREAD_TYPE_NONE;
  maxAllocations = UINT64_MAX;
  failAlways = false;
}

void SimulateStackOOMAfter(uint64_t checks, uint32_t thread, bool always) {
  Maybe<AutoLockHelperThreadState> lock;
  if (IsHelperThreadType(stackTargetThread) || IsHelperThreadType(thread)) {
    lock.emplace();
    HelperThreadState().waitForAllThreadsLocked(lock.ref());
  }

  MOZ_ASSERT(stackCheckCounter + checks > stackCheckCounter);
  MOZ_ASSERT(thread > js::THREAD_TYPE_NONE && thread < js::THREAD_TYPE_MAX);
  stackTargetThread = thread;
  maxStackChecks = stackCheckCounter + checks;
  stackCheckFailAlways = always;
}

void ResetSimulatedStackOOM() {
  Maybe<AutoLockHelperThreadState> lock;
  if (IsHelperThreadType(stackTargetThread)) {
    lock.emplace();
    HelperThreadState().waitForAllThreadsLocked(lock.ref());
  }

  stackTargetThread = THREAD_TYPE_NONE;
  maxStackChecks = UINT64_MAX;
  stackCheckFailAlways = false;
}

void SimulateInterruptAfter(uint64_t checks, uint32_t thread, bool always) {
  Maybe<AutoLockHelperThreadState> lock;
  if (IsHelperThreadType(interruptTargetThread) || IsHelperThreadType(thread)) {
    lock.emplace();
    HelperThreadState().waitForAllThreadsLocked(lock.ref());
  }

  MOZ_ASSERT(interruptCheckCounter + checks > interruptCheckCounter);
  MOZ_ASSERT(thread > js::THREAD_TYPE_NONE && thread < js::THREAD_TYPE_MAX);
  interruptTargetThread = thread;
  maxInterruptChecks = interruptCheckCounter + checks;
  interruptCheckFailAlways = always;
}

void ResetSimulatedInterrupt() {
  Maybe<AutoLockHelperThreadState> lock;
  if (IsHelperThreadType(interruptTargetThread)) {
    lock.emplace();
    HelperThreadState().waitForAllThreadsLocked(lock.ref());
  }

  interruptTargetThread = THREAD_TYPE_NONE;
  maxInterruptChecks = UINT64_MAX;
  interruptCheckFailAlways = false;
}

}  // namespace oom
}  // namespace js
#endif  // defined(DEBUG) || defined(JS_OOM_BREAKPOINT)

JS_PUBLIC_DATA arena_id_t js::MallocArena;

void js::InitMallocAllocator() { MallocArena = moz_create_arena(); }

void js::ShutDownMallocAllocator() {
  // Until Bug 1364359 is fixed it is unsafe to call moz_dispose_arena.
  // moz_dispose_arena(MallocArena);
}

JS_PUBLIC_API void JS_Assert(const char* s, const char* file, int ln) {
  MOZ_ReportAssertionFailure(s, file, ln);
  MOZ_CRASH();
}

#ifdef __linux__

#include <malloc.h>
#include <stdlib.h>

namespace js {

// This function calls all the vanilla heap allocation functions.  It is never
// called, and exists purely to help config/check_vanilla_allocations.py.  See
// that script for more details.
extern MOZ_COLD void AllTheNonBasicVanillaNewAllocations() {
  // posix_memalign and aligned_alloc aren't available on all Linux
  // configurations.
  // valloc was deprecated in Android 5.0
  // char* q;
  // posix_memalign((void**)&q, 16, 16);

  intptr_t p = intptr_t(malloc(16)) + intptr_t(calloc(1, 16)) +
               intptr_t(realloc(nullptr, 16)) + intptr_t(new char) +
               intptr_t(new char) + intptr_t(new char) +
               intptr_t(new char[16]) + intptr_t(memalign(16, 16)) +
               // intptr_t(q) +
               // intptr_t(aligned_alloc(16, 16)) +
               // intptr_t(valloc(4096)) +
               intptr_t(strdup("dummy"));

  printf("%u\n", uint32_t(p));  // make sure |p| is not optimized away

  free((int*)p);  // this would crash if ever actually called

  MOZ_CRASH();
}

}  // namespace js

#endif  // __linux__

#ifdef JS_BASIC_STATS

#include <math.h>

/*
 * Histogram bins count occurrences of values <= the bin label, as follows:
 *
 *   linear:  0,   1,   2,   3,   4,   5,   6,   7,   8,   9,  10 or more
 *     2**x:  0,   1,   2,   4,   8,  16,  32,  64, 128, 256, 512 or more
 *    10**x:  0,   1,  10, 100, 1e3, 1e4, 1e5, 1e6, 1e7, 1e8, 1e9 or more
 *
 * We wish to count occurrences of 0 and 1 values separately, always.
 */
static uint32_t BinToVal(unsigned logscale, unsigned bin) {
  MOZ_ASSERT(bin <= 10);
  if (bin <= 1 || logscale == 0) return bin;
  --bin;
  if (logscale == 2) return JS_BIT(bin);
  MOZ_ASSERT(logscale == 10);
  return uint32_t(pow(10.0, (double)bin));
}

static unsigned ValToBin(unsigned logscale, uint32_t val) {
  unsigned bin;

  if (val <= 1) return val;
  bin = (logscale == 10)
            ? (unsigned)ceil(log10((double)val))
            : (logscale == 2) ? (unsigned)CeilingLog2Size(val) : val;
  return Min(bin, 10U);
}

void JS_BasicStatsAccum(JSBasicStats* bs, uint32_t val) {
  unsigned oldscale, newscale, bin;
  double mean;

  ++bs->num;
  if (bs->max < val) bs->max = val;
  bs->sum += val;
  bs->sqsum += (double)val * val;

  oldscale = bs->logscale;
  if (oldscale != 10) {
    mean = bs->sum / bs->num;
    if (bs->max > 16 && mean > 8) {
      newscale = (bs->max > 1e6 && mean > 1000) ? 10 : 2;
      if (newscale != oldscale) {
        uint32_t newhist[11], newbin;

        PodArrayZero(newhist);
        for (bin = 0; bin <= 10; bin++) {
          newbin = ValToBin(newscale, BinToVal(oldscale, bin));
          newhist[newbin] += bs->hist[bin];
        }
        js_memcpy(bs->hist, newhist, sizeof bs->hist);
        bs->logscale = newscale;
      }
    }
  }

  bin = ValToBin(bs->logscale, val);
  ++bs->hist[bin];
}

double JS_MeanAndStdDev(uint32_t num, double sum, double sqsum, double* sigma) {
  double var;

  if (num == 0 || sum == 0) {
    *sigma = 0;
    return 0;
  }

  var = num * sqsum - sum * sum;
  if (var < 0 || num == 1)
    var = 0;
  else
    var /= (double)num * (num - 1);

  /* Windows says sqrt(0.0) is "-1.#J" (?!) so we must test. */
  *sigma = (var != 0) ? sqrt(var) : 0;
  return sum / num;
}

void JS_DumpBasicStats(JSBasicStats* bs, const char* title, FILE* fp) {
  double mean, sigma;

  mean = JS_MeanAndStdDevBS(bs, &sigma);
  fprintf(fp, "\nmean %s %g, std. deviation %g, max %lu\n", title, mean, sigma,
          (unsigned long)bs->max);
  JS_DumpHistogram(bs, fp);
}

void JS_DumpHistogram(JSBasicStats* bs, FILE* fp) {
  unsigned bin;
  uint32_t cnt, max;
  double sum, mean;

  for (bin = 0, max = 0, sum = 0; bin <= 10; bin++) {
    cnt = bs->hist[bin];
    if (max < cnt) max = cnt;
    sum += cnt;
  }
  mean = sum / cnt;
  for (bin = 0; bin <= 10; bin++) {
    unsigned val = BinToVal(bs->logscale, bin);
    unsigned end = (bin == 10) ? 0 : BinToVal(bs->logscale, bin + 1);
    cnt = bs->hist[bin];
    if (val + 1 == end)
      fprintf(fp, "        [%6u]", val);
    else if (end != 0)
      fprintf(fp, "[%6u, %6u]", val, end - 1);
    else
      fprintf(fp, "[%6u,   +inf]", val);
    fprintf(fp, ": %8u ", cnt);
    if (cnt != 0) {
      if (max > 1e6 && mean > 1e3)
        cnt = uint32_t(ceil(log10((double)cnt)));
      else if (max > 16 && mean > 8)
        cnt = CeilingLog2Size(cnt);
      for (unsigned i = 0; i < cnt; i++) putc('*', fp);
    }
    putc('\n', fp);
  }
}

#endif /* JS_BASIC_STATS */