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-rw-r--r--js/src/gc/Nursery.cpp1930
1 files changed, 1930 insertions, 0 deletions
diff --git a/js/src/gc/Nursery.cpp b/js/src/gc/Nursery.cpp
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+++ b/js/src/gc/Nursery.cpp
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+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*-
+ * vim: set ts=8 sw=2 et tw=80:
+ *
+ * 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/. */
+
+#include "gc/Nursery-inl.h"
+
+#include "mozilla/DebugOnly.h"
+#include "mozilla/IntegerPrintfMacros.h"
+#include "mozilla/ScopeExit.h"
+#include "mozilla/TimeStamp.h"
+
+#include <algorithm>
+#include <cmath>
+#include <utility>
+
+#include "builtin/MapObject.h"
+#include "debugger/DebugAPI.h"
+#include "gc/GCInternals.h"
+#include "gc/GCLock.h"
+#include "gc/GCProbes.h"
+#include "gc/Memory.h"
+#include "gc/PublicIterators.h"
+#include "gc/Tenuring.h"
+#include "jit/JitFrames.h"
+#include "jit/JitRealm.h"
+#include "util/DifferentialTesting.h"
+#include "util/GetPidProvider.h" // getpid()
+#include "util/Poison.h"
+#include "vm/JSONPrinter.h"
+#include "vm/Realm.h"
+#include "vm/Time.h"
+
+#include "gc/Heap-inl.h"
+#include "gc/Marking-inl.h"
+#include "gc/Zone-inl.h"
+#include "vm/GeckoProfiler-inl.h"
+
+using namespace js;
+using namespace gc;
+
+using mozilla::DebugOnly;
+using mozilla::PodCopy;
+using mozilla::TimeDuration;
+using mozilla::TimeStamp;
+
+#ifdef JS_GC_ZEAL
+constexpr uint32_t CanaryMagicValue = 0xDEADB15D;
+
+struct alignas(gc::CellAlignBytes) js::Nursery::Canary {
+ uint32_t magicValue;
+ Canary* next;
+};
+#endif
+
+namespace js {
+struct NurseryChunk : public ChunkBase {
+ char data[Nursery::NurseryChunkUsableSize];
+
+ static NurseryChunk* fromChunk(gc::TenuredChunk* chunk);
+
+ explicit NurseryChunk(JSRuntime* runtime)
+ : ChunkBase(runtime, &runtime->gc.storeBuffer()) {}
+
+ void poisonAndInit(JSRuntime* rt, size_t size = ChunkSize);
+ void poisonRange(size_t from, size_t size, uint8_t value,
+ MemCheckKind checkKind);
+ void poisonAfterEvict(size_t extent = ChunkSize);
+
+ // Mark pages from startOffset to the end of the chunk as unused. The start
+ // offset must be after the first page, which contains the chunk header and is
+ // not marked as unused.
+ void markPagesUnusedHard(size_t startOffset);
+
+ // Mark pages from the second page of the chunk to endOffset as in use,
+ // following a call to markPagesUnusedHard.
+ [[nodiscard]] bool markPagesInUseHard(size_t endOffset);
+
+ uintptr_t start() const { return uintptr_t(&data); }
+ uintptr_t end() const { return uintptr_t(this) + ChunkSize; }
+};
+static_assert(sizeof(js::NurseryChunk) == gc::ChunkSize,
+ "Nursery chunk size must match gc::Chunk size.");
+
+} // namespace js
+
+inline void js::NurseryChunk::poisonAndInit(JSRuntime* rt, size_t size) {
+ MOZ_ASSERT(size >= sizeof(ChunkBase));
+ MOZ_ASSERT(size <= ChunkSize);
+ poisonRange(0, size, JS_FRESH_NURSERY_PATTERN, MemCheckKind::MakeUndefined);
+ new (this) NurseryChunk(rt);
+}
+
+inline void js::NurseryChunk::poisonRange(size_t from, size_t size,
+ uint8_t value,
+ MemCheckKind checkKind) {
+ MOZ_ASSERT(from + size <= ChunkSize);
+
+ auto* start = reinterpret_cast<uint8_t*>(this) + from;
+
+ // We can poison the same chunk more than once, so first make sure memory
+ // sanitizers will let us poison it.
+ MOZ_MAKE_MEM_UNDEFINED(start, size);
+ Poison(start, value, size, checkKind);
+}
+
+inline void js::NurseryChunk::poisonAfterEvict(size_t extent) {
+ MOZ_ASSERT(extent <= ChunkSize);
+ poisonRange(sizeof(ChunkBase), extent - sizeof(ChunkBase),
+ JS_SWEPT_NURSERY_PATTERN, MemCheckKind::MakeNoAccess);
+}
+
+inline void js::NurseryChunk::markPagesUnusedHard(size_t startOffset) {
+ MOZ_ASSERT(startOffset >= sizeof(ChunkBase)); // Don't touch the header.
+ MOZ_ASSERT(startOffset >= SystemPageSize());
+ MOZ_ASSERT(startOffset <= ChunkSize);
+ uintptr_t start = uintptr_t(this) + startOffset;
+ size_t length = ChunkSize - startOffset;
+ MarkPagesUnusedHard(reinterpret_cast<void*>(start), length);
+}
+
+inline bool js::NurseryChunk::markPagesInUseHard(size_t endOffset) {
+ MOZ_ASSERT(endOffset >= sizeof(ChunkBase));
+ MOZ_ASSERT(endOffset >= SystemPageSize());
+ MOZ_ASSERT(endOffset <= ChunkSize);
+ uintptr_t start = uintptr_t(this) + SystemPageSize();
+ size_t length = endOffset - SystemPageSize();
+ return MarkPagesInUseHard(reinterpret_cast<void*>(start), length);
+}
+
+// static
+inline js::NurseryChunk* js::NurseryChunk::fromChunk(TenuredChunk* chunk) {
+ return reinterpret_cast<NurseryChunk*>(chunk);
+}
+
+js::NurseryDecommitTask::NurseryDecommitTask(gc::GCRuntime* gc)
+ : GCParallelTask(gc, gcstats::PhaseKind::NONE) {
+ // This can occur outside GCs so doesn't have a stats phase.
+}
+
+bool js::NurseryDecommitTask::isEmpty(
+ const AutoLockHelperThreadState& lock) const {
+ return chunksToDecommit().empty() && !partialChunk;
+}
+
+bool js::NurseryDecommitTask::reserveSpaceForBytes(size_t nbytes) {
+ MOZ_ASSERT(isIdle());
+ size_t nchunks = HowMany(nbytes, ChunkSize);
+ return chunksToDecommit().reserve(nchunks);
+}
+
+void js::NurseryDecommitTask::queueChunk(
+ NurseryChunk* chunk, const AutoLockHelperThreadState& lock) {
+ MOZ_ASSERT(isIdle(lock));
+ MOZ_ALWAYS_TRUE(chunksToDecommit().append(chunk));
+}
+
+void js::NurseryDecommitTask::queueRange(
+ size_t newCapacity, NurseryChunk& newChunk,
+ const AutoLockHelperThreadState& lock) {
+ MOZ_ASSERT(isIdle(lock));
+ MOZ_ASSERT(!partialChunk);
+ MOZ_ASSERT(newCapacity < ChunkSize);
+ MOZ_ASSERT(newCapacity % SystemPageSize() == 0);
+
+ partialChunk = &newChunk;
+ partialCapacity = newCapacity;
+}
+
+void js::NurseryDecommitTask::run(AutoLockHelperThreadState& lock) {
+ while (!chunksToDecommit().empty()) {
+ NurseryChunk* nurseryChunk = chunksToDecommit().popCopy();
+ AutoUnlockHelperThreadState unlock(lock);
+ nurseryChunk->~NurseryChunk();
+ TenuredChunk* tenuredChunk = TenuredChunk::emplace(
+ nurseryChunk, gc, /* allMemoryCommitted = */ false);
+ AutoLockGC lock(gc);
+ gc->recycleChunk(tenuredChunk, lock);
+ }
+
+ if (partialChunk) {
+ {
+ AutoUnlockHelperThreadState unlock(lock);
+ partialChunk->markPagesUnusedHard(partialCapacity);
+ }
+ partialChunk = nullptr;
+ partialCapacity = 0;
+ }
+}
+
+js::Nursery::Nursery(GCRuntime* gc)
+ : gc(gc),
+ position_(0),
+ currentStartChunk_(0),
+ currentStartPosition_(0),
+ currentEnd_(0),
+ currentStringEnd_(0),
+ currentBigIntEnd_(0),
+ currentChunk_(0),
+ capacity_(0),
+ timeInChunkAlloc_(0),
+ enableProfiling_(false),
+ profileThreshold_(0),
+ canAllocateStrings_(true),
+ canAllocateBigInts_(true),
+ reportDeduplications_(false),
+ reportPretenuring_(false),
+ reportPretenuringThreshold_(0),
+ minorGCTriggerReason_(JS::GCReason::NO_REASON),
+ hasRecentGrowthData(false),
+ smoothedTargetSize(0.0),
+ decommitTask(gc)
+#ifdef JS_GC_ZEAL
+ ,
+ lastCanary_(nullptr)
+#endif
+{
+ const char* env = getenv("MOZ_NURSERY_STRINGS");
+ if (env && *env) {
+ canAllocateStrings_ = (*env == '1');
+ }
+ env = getenv("MOZ_NURSERY_BIGINTS");
+ if (env && *env) {
+ canAllocateBigInts_ = (*env == '1');
+ }
+}
+
+static void PrintAndExit(const char* message) {
+ fprintf(stderr, "%s", message);
+ exit(0);
+}
+
+static const char* GetEnvVar(const char* name, const char* helpMessage) {
+ const char* value = getenv(name);
+ if (!value) {
+ return nullptr;
+ }
+
+ if (strcmp(value, "help") == 0) {
+ PrintAndExit(helpMessage);
+ }
+
+ return value;
+}
+
+static bool GetBoolEnvVar(const char* name, const char* helpMessage) {
+ const char* env = GetEnvVar(name, helpMessage);
+ return env && bool(atoi(env));
+}
+
+static void ReadReportPretenureEnv(const char* name, const char* helpMessage,
+ bool* enabled, size_t* threshold) {
+ *enabled = false;
+ *threshold = 0;
+
+ const char* env = GetEnvVar(name, helpMessage);
+ if (!env) {
+ return;
+ }
+
+ char* end;
+ *threshold = strtol(env, &end, 10);
+ if (end == env || *end) {
+ PrintAndExit(helpMessage);
+ }
+
+ *enabled = true;
+}
+
+bool js::Nursery::init(AutoLockGCBgAlloc& lock) {
+ ReadProfileEnv("JS_GC_PROFILE_NURSERY",
+ "Report minor GCs taking at least N microseconds.\n",
+ &enableProfiling_, &profileWorkers_, &profileThreshold_);
+
+ reportDeduplications_ = GetBoolEnvVar(
+ "JS_GC_REPORT_STATS",
+ "JS_GC_REPORT_STATS=1\n"
+ "\tAfter a minor GC, report how many strings were deduplicated.\n");
+
+ ReadReportPretenureEnv(
+ "JS_GC_REPORT_PRETENURE",
+ "JS_GC_REPORT_PRETENURE=N\n"
+ "\tAfter a minor GC, report information about pretenuring, including\n"
+ "\tallocation sites with at least N allocations.\n",
+ &reportPretenuring_, &reportPretenuringThreshold_);
+
+ if (!gc->storeBuffer().enable()) {
+ return false;
+ }
+
+ return initFirstChunk(lock);
+}
+
+js::Nursery::~Nursery() { disable(); }
+
+void js::Nursery::enable() {
+ MOZ_ASSERT(isEmpty());
+ MOZ_ASSERT(!gc->isVerifyPreBarriersEnabled());
+ if (isEnabled()) {
+ return;
+ }
+
+ {
+ AutoLockGCBgAlloc lock(gc);
+ if (!initFirstChunk(lock)) {
+ // If we fail to allocate memory, the nursery will not be enabled.
+ return;
+ }
+ }
+
+#ifdef JS_GC_ZEAL
+ if (gc->hasZealMode(ZealMode::GenerationalGC)) {
+ enterZealMode();
+ }
+#endif
+
+ // This should always succeed after the first time it's called.
+ MOZ_ALWAYS_TRUE(gc->storeBuffer().enable());
+}
+
+bool js::Nursery::initFirstChunk(AutoLockGCBgAlloc& lock) {
+ MOZ_ASSERT(!isEnabled());
+
+ capacity_ = tunables().gcMinNurseryBytes();
+
+ if (!decommitTask.reserveSpaceForBytes(capacity_) ||
+ !allocateNextChunk(0, lock)) {
+ capacity_ = 0;
+ return false;
+ }
+
+ setCurrentChunk(0);
+ setStartPosition();
+ poisonAndInitCurrentChunk();
+
+ // Clear any information about previous collections.
+ clearRecentGrowthData();
+
+ return true;
+}
+
+void js::Nursery::disable() {
+ stringDeDupSet.reset();
+ MOZ_ASSERT(isEmpty());
+ if (!isEnabled()) {
+ return;
+ }
+
+ // Free all chunks.
+ decommitTask.join();
+ freeChunksFrom(0);
+ decommitTask.runFromMainThread();
+
+ capacity_ = 0;
+
+ // We must reset currentEnd_ so that there is no space for anything in the
+ // nursery. JIT'd code uses this even if the nursery is disabled.
+ currentEnd_ = 0;
+ currentStringEnd_ = 0;
+ currentBigIntEnd_ = 0;
+ position_ = 0;
+ gc->storeBuffer().disable();
+}
+
+void js::Nursery::enableStrings() {
+ MOZ_ASSERT(isEmpty());
+ canAllocateStrings_ = true;
+ currentStringEnd_ = currentEnd_;
+}
+
+void js::Nursery::disableStrings() {
+ MOZ_ASSERT(isEmpty());
+ canAllocateStrings_ = false;
+ currentStringEnd_ = 0;
+}
+
+void js::Nursery::enableBigInts() {
+ MOZ_ASSERT(isEmpty());
+ canAllocateBigInts_ = true;
+ currentBigIntEnd_ = currentEnd_;
+}
+
+void js::Nursery::disableBigInts() {
+ MOZ_ASSERT(isEmpty());
+ canAllocateBigInts_ = false;
+ currentBigIntEnd_ = 0;
+}
+
+bool js::Nursery::isEmpty() const {
+ if (!isEnabled()) {
+ return true;
+ }
+
+ if (!gc->hasZealMode(ZealMode::GenerationalGC)) {
+ MOZ_ASSERT(currentStartChunk_ == 0);
+ MOZ_ASSERT(currentStartPosition_ == chunk(0).start());
+ }
+ return position() == currentStartPosition_;
+}
+
+#ifdef JS_GC_ZEAL
+void js::Nursery::enterZealMode() {
+ if (!isEnabled()) {
+ return;
+ }
+
+ MOZ_ASSERT(isEmpty());
+
+ decommitTask.join();
+
+ AutoEnterOOMUnsafeRegion oomUnsafe;
+
+ if (isSubChunkMode()) {
+ {
+ if (!chunk(0).markPagesInUseHard(ChunkSize)) {
+ oomUnsafe.crash("Out of memory trying to extend chunk for zeal mode");
+ }
+ }
+
+ // It'd be simpler to poison the whole chunk, but we can't do that
+ // because the nursery might be partially used.
+ chunk(0).poisonRange(capacity_, ChunkSize - capacity_,
+ JS_FRESH_NURSERY_PATTERN, MemCheckKind::MakeUndefined);
+ }
+
+ capacity_ = RoundUp(tunables().gcMaxNurseryBytes(), ChunkSize);
+
+ if (!decommitTask.reserveSpaceForBytes(capacity_)) {
+ oomUnsafe.crash("Nursery::enterZealMode");
+ }
+
+ setCurrentEnd();
+}
+
+void js::Nursery::leaveZealMode() {
+ if (!isEnabled()) {
+ return;
+ }
+
+ MOZ_ASSERT(isEmpty());
+
+ setCurrentChunk(0);
+ setStartPosition();
+ poisonAndInitCurrentChunk();
+}
+#endif // JS_GC_ZEAL
+
+JSObject* js::Nursery::allocateObject(gc::AllocSite* site, size_t size,
+ size_t nDynamicSlots,
+ const JSClass* clasp) {
+ // Ensure there's enough space to replace the contents with a
+ // RelocationOverlay.
+ MOZ_ASSERT(size >= sizeof(RelocationOverlay));
+
+ // Sanity check the finalizer.
+ MOZ_ASSERT_IF(clasp->hasFinalize(), CanNurseryAllocateFinalizedClass(clasp) ||
+ clasp->isProxyObject());
+
+ auto* obj = reinterpret_cast<JSObject*>(
+ allocateCell(site, size, JS::TraceKind::Object));
+ if (!obj) {
+ return nullptr;
+ }
+
+ // If we want external slots, add them.
+ ObjectSlots* slotsHeader = nullptr;
+ if (nDynamicSlots) {
+ MOZ_ASSERT(clasp->isNativeObject());
+ void* allocation =
+ allocateBuffer(site->zone(), ObjectSlots::allocSize(nDynamicSlots));
+ if (!allocation) {
+ // It is safe to leave the allocated object uninitialized, since we
+ // do not visit unallocated things in the nursery.
+ return nullptr;
+ }
+ slotsHeader = new (allocation) ObjectSlots(nDynamicSlots, 0);
+ }
+
+ // Store slots pointer directly in new object. If no dynamic slots were
+ // requested, caller must initialize slots_ field itself as needed. We
+ // don't know if the caller was a native object or not.
+ if (nDynamicSlots) {
+ static_cast<NativeObject*>(obj)->initSlots(slotsHeader->slots());
+ }
+
+ gcprobes::NurseryAlloc(obj, size);
+ return obj;
+}
+
+Cell* js::Nursery::allocateCell(gc::AllocSite* site, size_t size,
+ JS::TraceKind kind) {
+ // Ensure there's enough space to replace the contents with a
+ // RelocationOverlay.
+ MOZ_ASSERT(size >= sizeof(RelocationOverlay));
+ MOZ_ASSERT(size % CellAlignBytes == 0);
+
+ void* ptr = allocate(sizeof(NurseryCellHeader) + size);
+ if (!ptr) {
+ return nullptr;
+ }
+
+ new (ptr) NurseryCellHeader(site, kind);
+
+ auto cell =
+ reinterpret_cast<Cell*>(uintptr_t(ptr) + sizeof(NurseryCellHeader));
+
+ // Update the allocation site. This code is also inlined in
+ // MacroAssembler::updateAllocSite.
+ if (!site->isInAllocatedList()) {
+ pretenuringNursery.insertIntoAllocatedList(site);
+ }
+ site->incAllocCount();
+
+ gcprobes::NurseryAlloc(cell, kind);
+ return cell;
+}
+
+Cell* js::Nursery::allocateString(gc::AllocSite* site, size_t size) {
+ Cell* cell = allocateCell(site, size, JS::TraceKind::String);
+ if (cell) {
+ site->zone()->nurseryAllocatedStrings++;
+ }
+ return cell;
+}
+
+inline void* js::Nursery::allocate(size_t size) {
+ MOZ_ASSERT(isEnabled());
+ MOZ_ASSERT(!JS::RuntimeHeapIsBusy());
+ MOZ_ASSERT(CurrentThreadCanAccessRuntime(runtime()));
+ MOZ_ASSERT_IF(currentChunk_ == currentStartChunk_,
+ position() >= currentStartPosition_);
+ MOZ_ASSERT(position() % CellAlignBytes == 0);
+ MOZ_ASSERT(size % CellAlignBytes == 0);
+
+#ifdef JS_GC_ZEAL
+ if (gc->hasZealMode(ZealMode::CheckNursery)) {
+ size += sizeof(Canary);
+ }
+#endif
+
+ if (MOZ_UNLIKELY(currentEnd() < position() + size)) {
+ return moveToNextChunkAndAllocate(size);
+ }
+
+ void* thing = (void*)position();
+ position_ = position() + size;
+ // We count this regardless of the profiler's state, assuming that it costs
+ // just as much to count it, as to check the profiler's state and decide not
+ // to count it.
+ stats().noteNurseryAlloc();
+
+ DebugOnlyPoison(thing, JS_ALLOCATED_NURSERY_PATTERN, size,
+ MemCheckKind::MakeUndefined);
+
+#ifdef JS_GC_ZEAL
+ if (gc->hasZealMode(ZealMode::CheckNursery)) {
+ writeCanary(position() - sizeof(Canary));
+ }
+#endif
+
+ return thing;
+}
+
+void* Nursery::moveToNextChunkAndAllocate(size_t size) {
+ MOZ_ASSERT(currentEnd() < position() + size);
+
+ unsigned chunkno = currentChunk_ + 1;
+ MOZ_ASSERT(chunkno <= maxChunkCount());
+ MOZ_ASSERT(chunkno <= allocatedChunkCount());
+ if (chunkno == maxChunkCount()) {
+ return nullptr;
+ }
+ if (chunkno == allocatedChunkCount()) {
+ TimeStamp start = TimeStamp::Now();
+ {
+ AutoLockGCBgAlloc lock(gc);
+ if (!allocateNextChunk(chunkno, lock)) {
+ return nullptr;
+ }
+ }
+ timeInChunkAlloc_ += TimeStamp::Now() - start;
+ MOZ_ASSERT(chunkno < allocatedChunkCount());
+ }
+ setCurrentChunk(chunkno);
+ poisonAndInitCurrentChunk();
+
+ // We know there's enough space to allocate now so we can call allocate()
+ // recursively. Adjust the size for the nursery canary which it will add on.
+ MOZ_ASSERT(currentEnd() >= position() + size);
+#ifdef JS_GC_ZEAL
+ if (gc->hasZealMode(ZealMode::CheckNursery)) {
+ size -= sizeof(Canary);
+ }
+#endif
+ return allocate(size);
+}
+
+#ifdef JS_GC_ZEAL
+inline void Nursery::writeCanary(uintptr_t address) {
+ auto* canary = reinterpret_cast<Canary*>(address);
+ new (canary) Canary{CanaryMagicValue, nullptr};
+ if (lastCanary_) {
+ MOZ_ASSERT(!lastCanary_->next);
+ lastCanary_->next = canary;
+ }
+ lastCanary_ = canary;
+}
+#endif
+
+void* js::Nursery::allocateBuffer(Zone* zone, size_t nbytes) {
+ MOZ_ASSERT(nbytes > 0);
+
+ if (nbytes <= MaxNurseryBufferSize) {
+ void* buffer = allocate(nbytes);
+ if (buffer) {
+ return buffer;
+ }
+ }
+
+ void* buffer = zone->pod_malloc<uint8_t>(nbytes);
+ if (buffer && !registerMallocedBuffer(buffer, nbytes)) {
+ js_free(buffer);
+ return nullptr;
+ }
+ return buffer;
+}
+
+void* js::Nursery::allocateBuffer(JSObject* obj, size_t nbytes) {
+ MOZ_ASSERT(obj);
+ MOZ_ASSERT(nbytes > 0);
+
+ if (!IsInsideNursery(obj)) {
+ return obj->zone()->pod_malloc<uint8_t>(nbytes);
+ }
+ return allocateBuffer(obj->zone(), nbytes);
+}
+
+void* js::Nursery::allocateBufferSameLocation(JSObject* obj, size_t nbytes) {
+ MOZ_ASSERT(obj);
+ MOZ_ASSERT(nbytes > 0);
+ MOZ_ASSERT(nbytes <= MaxNurseryBufferSize);
+
+ if (!IsInsideNursery(obj)) {
+ return obj->zone()->pod_malloc<uint8_t>(nbytes);
+ }
+
+ return allocate(nbytes);
+}
+
+void* js::Nursery::allocateZeroedBuffer(
+ Zone* zone, size_t nbytes, arena_id_t arena /*= js::MallocArena*/) {
+ MOZ_ASSERT(nbytes > 0);
+
+ if (nbytes <= MaxNurseryBufferSize) {
+ void* buffer = allocate(nbytes);
+ if (buffer) {
+ memset(buffer, 0, nbytes);
+ return buffer;
+ }
+ }
+
+ void* buffer = zone->pod_arena_calloc<uint8_t>(arena, nbytes);
+ if (buffer && !registerMallocedBuffer(buffer, nbytes)) {
+ js_free(buffer);
+ return nullptr;
+ }
+ return buffer;
+}
+
+void* js::Nursery::allocateZeroedBuffer(
+ JSObject* obj, size_t nbytes, arena_id_t arena /*= js::MallocArena*/) {
+ MOZ_ASSERT(obj);
+ MOZ_ASSERT(nbytes > 0);
+
+ if (!IsInsideNursery(obj)) {
+ return obj->zone()->pod_arena_calloc<uint8_t>(arena, nbytes);
+ }
+ return allocateZeroedBuffer(obj->zone(), nbytes, arena);
+}
+
+void* js::Nursery::reallocateBuffer(Zone* zone, Cell* cell, void* oldBuffer,
+ size_t oldBytes, size_t newBytes) {
+ if (!IsInsideNursery(cell)) {
+ MOZ_ASSERT(!isInside(oldBuffer));
+ return zone->pod_realloc<uint8_t>((uint8_t*)oldBuffer, oldBytes, newBytes);
+ }
+
+ if (!isInside(oldBuffer)) {
+ MOZ_ASSERT(mallocedBufferBytes >= oldBytes);
+ void* newBuffer =
+ zone->pod_realloc<uint8_t>((uint8_t*)oldBuffer, oldBytes, newBytes);
+ if (newBuffer) {
+ if (oldBuffer != newBuffer) {
+ MOZ_ALWAYS_TRUE(
+ mallocedBuffers.rekeyAs(oldBuffer, newBuffer, newBuffer));
+ }
+ mallocedBufferBytes -= oldBytes;
+ mallocedBufferBytes += newBytes;
+ }
+ return newBuffer;
+ }
+
+ // The nursery cannot make use of the returned slots data.
+ if (newBytes < oldBytes) {
+ return oldBuffer;
+ }
+
+ void* newBuffer = allocateBuffer(zone, newBytes);
+ if (newBuffer) {
+ PodCopy((uint8_t*)newBuffer, (uint8_t*)oldBuffer, oldBytes);
+ }
+ return newBuffer;
+}
+
+void* js::Nursery::allocateBuffer(JS::BigInt* bi, size_t nbytes) {
+ MOZ_ASSERT(bi);
+ MOZ_ASSERT(nbytes > 0);
+
+ if (!IsInsideNursery(bi)) {
+ return bi->zone()->pod_malloc<uint8_t>(nbytes);
+ }
+ return allocateBuffer(bi->zone(), nbytes);
+}
+
+void js::Nursery::freeBuffer(void* buffer, size_t nbytes) {
+ if (!isInside(buffer)) {
+ removeMallocedBuffer(buffer, nbytes);
+ js_free(buffer);
+ }
+}
+
+#ifdef DEBUG
+/* static */
+inline bool Nursery::checkForwardingPointerLocation(void* ptr,
+ bool expectedInside) {
+ if (isInside(ptr) == expectedInside) {
+ return true;
+ }
+
+ // If a zero-capacity elements header lands right at the end of a chunk then
+ // elements data will appear to be in the next chunk. If we have a pointer to
+ // the very start of a chunk, check the previous chunk.
+ if ((uintptr_t(ptr) & ChunkMask) == 0 &&
+ isInside(reinterpret_cast<uint8_t*>(ptr) - 1) == expectedInside) {
+ return true;
+ }
+
+ return false;
+}
+#endif
+
+void Nursery::setIndirectForwardingPointer(void* oldData, void* newData) {
+ MOZ_ASSERT(checkForwardingPointerLocation(oldData, true));
+ MOZ_ASSERT(checkForwardingPointerLocation(newData, false));
+
+ AutoEnterOOMUnsafeRegion oomUnsafe;
+#ifdef DEBUG
+ if (ForwardedBufferMap::Ptr p = forwardedBuffers.lookup(oldData)) {
+ MOZ_ASSERT(p->value() == newData);
+ }
+#endif
+ if (!forwardedBuffers.put(oldData, newData)) {
+ oomUnsafe.crash("Nursery::setForwardingPointer");
+ }
+}
+
+#ifdef DEBUG
+static bool IsWriteableAddress(void* ptr) {
+ auto* vPtr = reinterpret_cast<volatile uint64_t*>(ptr);
+ *vPtr = *vPtr;
+ return true;
+}
+#endif
+
+void js::Nursery::forwardBufferPointer(uintptr_t* pSlotsElems) {
+ // Read the current pointer value which may be one of:
+ // - Non-nursery pointer
+ // - Nursery-allocated buffer
+ // - A BufferRelocationOverlay inside the nursery
+ //
+ // Note: The buffer has already be relocated. We are just patching stale
+ // pointers now.
+ auto* buffer = reinterpret_cast<void*>(*pSlotsElems);
+
+ if (!isInside(buffer)) {
+ return;
+ }
+
+ // The new location for this buffer is either stored inline with it or in
+ // the forwardedBuffers table.
+ if (ForwardedBufferMap::Ptr p = forwardedBuffers.lookup(buffer)) {
+ buffer = p->value();
+ // It's not valid to assert IsWriteableAddress for indirect forwarding
+ // pointers because the size of the allocation could be less than a word.
+ } else {
+ BufferRelocationOverlay* reloc =
+ static_cast<BufferRelocationOverlay*>(buffer);
+ buffer = *reloc;
+ MOZ_ASSERT(IsWriteableAddress(buffer));
+ }
+
+ MOZ_ASSERT(!isInside(buffer));
+ *pSlotsElems = reinterpret_cast<uintptr_t>(buffer);
+}
+
+inline double js::Nursery::calcPromotionRate(bool* validForTenuring) const {
+ MOZ_ASSERT(validForTenuring);
+
+ if (previousGC.nurseryUsedBytes == 0) {
+ *validForTenuring = false;
+ return 0.0;
+ }
+
+ double used = double(previousGC.nurseryUsedBytes);
+ double capacity = double(previousGC.nurseryCapacity);
+ double tenured = double(previousGC.tenuredBytes);
+
+ // We should only use the promotion rate to make tenuring decisions if it's
+ // likely to be valid. The criterion we use is that the nursery was at least
+ // 90% full.
+ *validForTenuring = used > capacity * 0.9;
+
+ return tenured / used;
+}
+
+void js::Nursery::renderProfileJSON(JSONPrinter& json) const {
+ if (!isEnabled()) {
+ json.beginObject();
+ json.property("status", "nursery disabled");
+ json.endObject();
+ return;
+ }
+
+ if (previousGC.reason == JS::GCReason::NO_REASON) {
+ // If the nursery was empty when the last minorGC was requested, then
+ // no nursery collection will have been performed but JSON may still be
+ // requested. (And as a public API, this function should not crash in
+ // such a case.)
+ json.beginObject();
+ json.property("status", "nursery empty");
+ json.endObject();
+ return;
+ }
+
+ json.beginObject();
+
+ json.property("status", "complete");
+
+ json.property("reason", JS::ExplainGCReason(previousGC.reason));
+ json.property("bytes_tenured", previousGC.tenuredBytes);
+ json.property("cells_tenured", previousGC.tenuredCells);
+ json.property("strings_tenured",
+ stats().getStat(gcstats::STAT_STRINGS_TENURED));
+ json.property("strings_deduplicated",
+ stats().getStat(gcstats::STAT_STRINGS_DEDUPLICATED));
+ json.property("bigints_tenured",
+ stats().getStat(gcstats::STAT_BIGINTS_TENURED));
+ json.property("bytes_used", previousGC.nurseryUsedBytes);
+ json.property("cur_capacity", previousGC.nurseryCapacity);
+ const size_t newCapacity = capacity();
+ if (newCapacity != previousGC.nurseryCapacity) {
+ json.property("new_capacity", newCapacity);
+ }
+ if (previousGC.nurseryCommitted != previousGC.nurseryCapacity) {
+ json.property("lazy_capacity", previousGC.nurseryCommitted);
+ }
+ if (!timeInChunkAlloc_.IsZero()) {
+ json.property("chunk_alloc_us", timeInChunkAlloc_, json.MICROSECONDS);
+ }
+
+ // These counters only contain consistent data if the profiler is enabled,
+ // and then there's no guarentee.
+ if (runtime()->geckoProfiler().enabled()) {
+ json.property("cells_allocated_nursery",
+ stats().allocsSinceMinorGCNursery());
+ json.property("cells_allocated_tenured",
+ stats().allocsSinceMinorGCTenured());
+ }
+
+ if (stats().getStat(gcstats::STAT_NURSERY_STRING_REALMS_DISABLED)) {
+ json.property(
+ "nursery_string_realms_disabled",
+ stats().getStat(gcstats::STAT_NURSERY_STRING_REALMS_DISABLED));
+ }
+ if (stats().getStat(gcstats::STAT_NURSERY_BIGINT_REALMS_DISABLED)) {
+ json.property(
+ "nursery_bigint_realms_disabled",
+ stats().getStat(gcstats::STAT_NURSERY_BIGINT_REALMS_DISABLED));
+ }
+
+ json.beginObjectProperty("phase_times");
+
+#define EXTRACT_NAME(name, text) #name,
+ static const char* const names[] = {
+ FOR_EACH_NURSERY_PROFILE_TIME(EXTRACT_NAME)
+#undef EXTRACT_NAME
+ ""};
+
+ size_t i = 0;
+ for (auto time : profileDurations_) {
+ json.property(names[i++], time, json.MICROSECONDS);
+ }
+
+ json.endObject(); // timings value
+
+ json.endObject();
+}
+
+void js::Nursery::printCollectionProfile(JS::GCReason reason,
+ double promotionRate) {
+ stats().maybePrintProfileHeaders();
+
+ TimeDuration ts = collectionStartTime() - stats().creationTime();
+
+ FILE* file = stats().profileFile();
+ fprintf(
+ file, "MinorGC: %7zu %14p %10.6f %-20.20s %5.1f%% %6zu %6zu %6" PRIu32,
+ size_t(getpid()), runtime(), ts.ToSeconds(), JS::ExplainGCReason(reason),
+ promotionRate * 100, previousGC.nurseryCapacity / 1024, capacity() / 1024,
+ stats().getStat(gcstats::STAT_STRINGS_DEDUPLICATED));
+
+ printProfileDurations(file, profileDurations_);
+}
+
+void js::Nursery::printProfileHeader() {
+ FILE* file = stats().profileFile();
+ fprintf(
+ file,
+ "MinorGC: PID Runtime Timestamp Reason PRate "
+ "OldKB NewKB Dedup ");
+#define PRINT_HEADER(name, text) fprintf(file, " %-6.6s", text);
+ FOR_EACH_NURSERY_PROFILE_TIME(PRINT_HEADER)
+#undef PRINT_HEADER
+ fprintf(file, "\n");
+}
+
+// static
+void js::Nursery::printProfileDurations(FILE* file,
+ const ProfileDurations& times) {
+ for (auto time : times) {
+ fprintf(file, " %6" PRIi64, static_cast<int64_t>(time.ToMicroseconds()));
+ }
+ fprintf(file, "\n");
+}
+
+void js::Nursery::printTotalProfileTimes() {
+ if (!enableProfiling_) {
+ return;
+ }
+
+ FILE* file = stats().profileFile();
+ fprintf(file,
+ "MinorGC: %7zu %14p TOTALS: %7" PRIu64
+ " collections: %16" PRIu64,
+ size_t(getpid()), runtime(), gc->stringStats.deduplicatedStrings,
+ gc->minorGCCount());
+ printProfileDurations(file, totalDurations_);
+}
+
+void js::Nursery::maybeClearProfileDurations() {
+ for (auto& duration : profileDurations_) {
+ duration = mozilla::TimeDuration();
+ }
+}
+
+inline void js::Nursery::startProfile(ProfileKey key) {
+ startTimes_[key] = TimeStamp::Now();
+}
+
+inline void js::Nursery::endProfile(ProfileKey key) {
+ profileDurations_[key] = TimeStamp::Now() - startTimes_[key];
+ totalDurations_[key] += profileDurations_[key];
+}
+
+inline TimeStamp js::Nursery::collectionStartTime() const {
+ return startTimes_[ProfileKey::Total];
+}
+
+inline TimeStamp js::Nursery::lastCollectionEndTime() const {
+ return previousGC.endTime;
+}
+
+bool js::Nursery::shouldCollect() const {
+ if (!isEnabled()) {
+ return false;
+ }
+
+ if (isEmpty() && capacity() == tunables().gcMinNurseryBytes()) {
+ return false;
+ }
+
+ if (minorGCRequested()) {
+ return true;
+ }
+
+ // Eagerly collect the nursery in idle time if it's nearly full.
+ if (isNearlyFull()) {
+ return true;
+ }
+
+ // If the nursery is not being collected often then it may be taking up more
+ // space than necessary.
+ return isUnderused();
+}
+
+inline bool js::Nursery::isNearlyFull() const {
+ bool belowBytesThreshold =
+ freeSpace() < tunables().nurseryFreeThresholdForIdleCollection();
+ bool belowFractionThreshold =
+ double(freeSpace()) / double(capacity()) <
+ tunables().nurseryFreeThresholdForIdleCollectionFraction();
+
+ // We want to use belowBytesThreshold when the nursery is sufficiently large,
+ // and belowFractionThreshold when it's small.
+ //
+ // When the nursery is small then belowBytesThreshold is a lower threshold
+ // (triggered earlier) than belowFractionThreshold. So if the fraction
+ // threshold is true, the bytes one will be true also. The opposite is true
+ // when the nursery is large.
+ //
+ // Therefore, by the time we cross the threshold we care about, we've already
+ // crossed the other one, and we can boolean AND to use either condition
+ // without encoding any "is the nursery big/small" test/threshold. The point
+ // at which they cross is when the nursery is: BytesThreshold /
+ // FractionThreshold large.
+ //
+ // With defaults that's:
+ //
+ // 1MB = 256KB / 0.25
+ //
+ return belowBytesThreshold && belowFractionThreshold;
+}
+
+inline bool js::Nursery::isUnderused() const {
+ if (js::SupportDifferentialTesting() || !previousGC.endTime) {
+ return false;
+ }
+
+ if (capacity() == tunables().gcMinNurseryBytes()) {
+ return false;
+ }
+
+ // If the nursery is above its minimum size, collect it every so often if we
+ // have idle time. This allows the nursery to shrink when it's not being
+ // used. There are other heuristics we could use for this, but this is the
+ // simplest.
+ TimeDuration timeSinceLastCollection = TimeStamp::Now() - previousGC.endTime;
+ return timeSinceLastCollection > tunables().nurseryTimeoutForIdleCollection();
+}
+
+// typeReason is the gcReason for specified type, for example,
+// FULL_CELL_PTR_OBJ_BUFFER is the gcReason for JSObject.
+static inline bool IsFullStoreBufferReason(JS::GCReason reason,
+ JS::GCReason typeReason) {
+ return reason == typeReason ||
+ reason == JS::GCReason::FULL_WHOLE_CELL_BUFFER ||
+ reason == JS::GCReason::FULL_GENERIC_BUFFER ||
+ reason == JS::GCReason::FULL_VALUE_BUFFER ||
+ reason == JS::GCReason::FULL_SLOT_BUFFER ||
+ reason == JS::GCReason::FULL_SHAPE_BUFFER;
+}
+
+void js::Nursery::collect(JS::GCOptions options, JS::GCReason reason) {
+ JSRuntime* rt = runtime();
+ MOZ_ASSERT(!rt->mainContextFromOwnThread()->suppressGC);
+
+ if (!isEnabled() || isEmpty()) {
+ // Our barriers are not always exact, and there may be entries in the
+ // storebuffer even when the nursery is disabled or empty. It's not safe
+ // to keep these entries as they may refer to tenured cells which may be
+ // freed after this point.
+ gc->storeBuffer().clear();
+
+ MOZ_ASSERT(!pretenuringNursery.hasAllocatedSites());
+ }
+
+ if (!isEnabled()) {
+ return;
+ }
+
+#ifdef JS_GC_ZEAL
+ if (gc->hasZealMode(ZealMode::CheckNursery)) {
+ for (auto canary = lastCanary_; canary; canary = canary->next) {
+ MOZ_ASSERT(canary->magicValue == CanaryMagicValue);
+ }
+ }
+ lastCanary_ = nullptr;
+#endif
+
+ stats().beginNurseryCollection(reason);
+ gcprobes::MinorGCStart();
+
+ stringDeDupSet.emplace();
+ auto guardStringDedupSet =
+ mozilla::MakeScopeExit([&] { stringDeDupSet.reset(); });
+
+ maybeClearProfileDurations();
+ startProfile(ProfileKey::Total);
+
+ previousGC.reason = JS::GCReason::NO_REASON;
+ previousGC.nurseryUsedBytes = usedSpace();
+ previousGC.nurseryCapacity = capacity();
+ previousGC.nurseryCommitted = committed();
+ previousGC.nurseryUsedChunkCount = currentChunk_ + 1;
+ previousGC.tenuredBytes = 0;
+ previousGC.tenuredCells = 0;
+
+ // If it isn't empty, it will call doCollection, and possibly after that
+ // isEmpty() will become true, so use another variable to keep track of the
+ // old empty state.
+ bool wasEmpty = isEmpty();
+ if (!wasEmpty) {
+ CollectionResult result = doCollection(reason);
+ // Don't include chunk headers when calculating nursery space, since this
+ // space does not represent data that can be tenured
+ MOZ_ASSERT(result.tenuredBytes <=
+ (previousGC.nurseryUsedBytes -
+ (sizeof(ChunkBase) * previousGC.nurseryUsedChunkCount)));
+
+ previousGC.reason = reason;
+ previousGC.tenuredBytes = result.tenuredBytes;
+ previousGC.tenuredCells = result.tenuredCells;
+ previousGC.nurseryUsedChunkCount = currentChunk_ + 1;
+ }
+
+ // Resize the nursery.
+ maybeResizeNursery(options, reason);
+
+ // Poison/initialise the first chunk.
+ if (previousGC.nurseryUsedBytes) {
+ // In most cases Nursery::clear() has not poisoned this chunk or marked it
+ // as NoAccess; so we only need to poison the region used during the last
+ // cycle. Also, if the heap was recently expanded we don't want to
+ // re-poison the new memory. In both cases we only need to poison until
+ // previousGC.nurseryUsedBytes.
+ //
+ // In cases where this is not true, like generational zeal mode or subchunk
+ // mode, poisonAndInitCurrentChunk() will ignore its parameter. It will
+ // also clamp the parameter.
+ poisonAndInitCurrentChunk(previousGC.nurseryUsedBytes);
+ }
+
+ bool validPromotionRate;
+ const double promotionRate = calcPromotionRate(&validPromotionRate);
+
+ startProfile(ProfileKey::Pretenure);
+ size_t sitesPretenured = 0;
+ if (!wasEmpty) {
+ sitesPretenured =
+ doPretenuring(rt, reason, validPromotionRate, promotionRate);
+ }
+ endProfile(ProfileKey::Pretenure);
+
+ // We ignore gcMaxBytes when allocating for minor collection. However, if we
+ // overflowed, we disable the nursery. The next time we allocate, we'll fail
+ // because bytes >= gcMaxBytes.
+ if (gc->heapSize.bytes() >= tunables().gcMaxBytes()) {
+ disable();
+ }
+
+ previousGC.endTime =
+ TimeStamp::Now(); // Must happen after maybeResizeNursery.
+ endProfile(ProfileKey::Total);
+ gc->incMinorGcNumber();
+
+ TimeDuration totalTime = profileDurations_[ProfileKey::Total];
+ sendTelemetry(reason, totalTime, wasEmpty, promotionRate, sitesPretenured);
+
+ stats().endNurseryCollection(reason);
+ gcprobes::MinorGCEnd();
+
+ timeInChunkAlloc_ = mozilla::TimeDuration();
+
+ js::StringStats prevStats = gc->stringStats;
+ js::StringStats& currStats = gc->stringStats;
+ currStats = js::StringStats();
+ for (ZonesIter zone(gc, WithAtoms); !zone.done(); zone.next()) {
+ currStats += zone->stringStats;
+ zone->previousGCStringStats = zone->stringStats;
+ }
+ stats().setStat(
+ gcstats::STAT_STRINGS_DEDUPLICATED,
+ currStats.deduplicatedStrings - prevStats.deduplicatedStrings);
+ if (ShouldPrintProfile(runtime(), enableProfiling_, profileWorkers_,
+ profileThreshold_, totalTime)) {
+ printCollectionProfile(reason, promotionRate);
+ }
+
+ if (reportDeduplications_) {
+ printDeduplicationData(prevStats, currStats);
+ }
+}
+
+void js::Nursery::sendTelemetry(JS::GCReason reason, TimeDuration totalTime,
+ bool wasEmpty, double promotionRate,
+ size_t sitesPretenured) {
+ JSRuntime* rt = runtime();
+ rt->metrics().GC_MINOR_REASON(uint32_t(reason));
+
+ // Long minor GCs are those that take more than 1ms.
+ bool wasLongMinorGC = totalTime.ToMilliseconds() > 1.0;
+ if (wasLongMinorGC) {
+ rt->metrics().GC_MINOR_REASON_LONG(uint32_t(reason));
+ }
+ rt->metrics().GC_MINOR_US(totalTime);
+ rt->metrics().GC_NURSERY_BYTES_2(committed());
+
+ if (!wasEmpty) {
+ rt->metrics().GC_PRETENURE_COUNT_2(sitesPretenured);
+ rt->metrics().GC_NURSERY_PROMOTION_RATE(promotionRate * 100);
+ }
+}
+
+void js::Nursery::printDeduplicationData(js::StringStats& prev,
+ js::StringStats& curr) {
+ if (curr.deduplicatedStrings > prev.deduplicatedStrings) {
+ fprintf(stderr,
+ "pid %zu: deduplicated %" PRIi64 " strings, %" PRIu64
+ " chars, %" PRIu64 " malloc bytes\n",
+ size_t(getpid()),
+ curr.deduplicatedStrings - prev.deduplicatedStrings,
+ curr.deduplicatedChars - prev.deduplicatedChars,
+ curr.deduplicatedBytes - prev.deduplicatedBytes);
+ }
+}
+
+js::Nursery::CollectionResult js::Nursery::doCollection(JS::GCReason reason) {
+ JSRuntime* rt = runtime();
+ AutoGCSession session(gc, JS::HeapState::MinorCollecting);
+ AutoSetThreadIsPerformingGC performingGC(rt->gcContext());
+ AutoStopVerifyingBarriers av(rt, false);
+ AutoDisableProxyCheck disableStrictProxyChecking;
+ mozilla::DebugOnly<AutoEnterOOMUnsafeRegion> oomUnsafeRegion;
+
+ // Move objects pointed to by roots from the nursery to the major heap.
+ TenuringTracer mover(rt, this);
+
+ // Trace everything considered as a root by a minor GC.
+ traceRoots(session, mover);
+
+ startProfile(ProfileKey::SweepCaches);
+ gc->purgeRuntimeForMinorGC();
+ endProfile(ProfileKey::SweepCaches);
+
+ // Most of the work is done here. This loop iterates over objects that have
+ // been moved to the major heap. If these objects have any outgoing pointers
+ // to the nursery, then those nursery objects get moved as well, until no
+ // objects are left to move. That is, we iterate to a fixed point.
+ startProfile(ProfileKey::CollectToObjFP);
+ mover.collectToObjectFixedPoint();
+ endProfile(ProfileKey::CollectToObjFP);
+
+ startProfile(ProfileKey::CollectToStrFP);
+ mover.collectToStringFixedPoint();
+ endProfile(ProfileKey::CollectToStrFP);
+
+ // Sweep to update any pointers to nursery objects that have now been
+ // tenured.
+ startProfile(ProfileKey::Sweep);
+ sweep();
+ endProfile(ProfileKey::Sweep);
+
+ // Update any slot or element pointers whose destination has been tenured.
+ startProfile(ProfileKey::UpdateJitActivations);
+ js::jit::UpdateJitActivationsForMinorGC(rt);
+ forwardedBuffers.clearAndCompact();
+ endProfile(ProfileKey::UpdateJitActivations);
+
+ startProfile(ProfileKey::ObjectsTenuredCallback);
+ gc->callObjectsTenuredCallback();
+ endProfile(ProfileKey::ObjectsTenuredCallback);
+
+ // Sweep.
+ startProfile(ProfileKey::FreeMallocedBuffers);
+ gc->queueBuffersForFreeAfterMinorGC(mallocedBuffers);
+ mallocedBufferBytes = 0;
+ endProfile(ProfileKey::FreeMallocedBuffers);
+
+ startProfile(ProfileKey::ClearNursery);
+ clear();
+ endProfile(ProfileKey::ClearNursery);
+
+ startProfile(ProfileKey::ClearStoreBuffer);
+ gc->storeBuffer().clear();
+ endProfile(ProfileKey::ClearStoreBuffer);
+
+ // Purge the StringToAtomCache. This has to happen at the end because the
+ // cache is used when tenuring strings.
+ startProfile(ProfileKey::PurgeStringToAtomCache);
+ runtime()->caches().stringToAtomCache.purge();
+ endProfile(ProfileKey::PurgeStringToAtomCache);
+
+ // Make sure hashtables have been updated after the collection.
+ startProfile(ProfileKey::CheckHashTables);
+#ifdef JS_GC_ZEAL
+ if (gc->hasZealMode(ZealMode::CheckHashTablesOnMinorGC)) {
+ runtime()->caches().checkEvalCacheAfterMinorGC();
+ gc->checkHashTablesAfterMovingGC();
+ }
+#endif
+ endProfile(ProfileKey::CheckHashTables);
+
+ return {mover.getTenuredSize(), mover.getTenuredCells()};
+}
+
+void js::Nursery::traceRoots(AutoGCSession& session, TenuringTracer& mover) {
+ {
+ // Suppress the sampling profiler to prevent it observing moved functions.
+ AutoSuppressProfilerSampling suppressProfiler(
+ runtime()->mainContextFromOwnThread());
+
+ // Trace the store buffer. This must happen first.
+ StoreBuffer& sb = gc->storeBuffer();
+
+ // Strings in the whole cell buffer must be traced first, in order to mark
+ // tenured dependent strings' bases as non-deduplicatable. The rest of
+ // nursery collection (whole non-string cells, edges, etc.) can happen
+ // later.
+ startProfile(ProfileKey::TraceWholeCells);
+ sb.traceWholeCells(mover);
+ endProfile(ProfileKey::TraceWholeCells);
+
+ startProfile(ProfileKey::TraceValues);
+ sb.traceValues(mover);
+ endProfile(ProfileKey::TraceValues);
+
+ startProfile(ProfileKey::TraceCells);
+ sb.traceCells(mover);
+ endProfile(ProfileKey::TraceCells);
+
+ startProfile(ProfileKey::TraceSlots);
+ sb.traceSlots(mover);
+ endProfile(ProfileKey::TraceSlots);
+
+ startProfile(ProfileKey::TraceGenericEntries);
+ sb.traceGenericEntries(&mover);
+ endProfile(ProfileKey::TraceGenericEntries);
+
+ startProfile(ProfileKey::MarkRuntime);
+ gc->traceRuntimeForMinorGC(&mover, session);
+ endProfile(ProfileKey::MarkRuntime);
+ }
+
+ startProfile(ProfileKey::MarkDebugger);
+ {
+ gcstats::AutoPhase ap(stats(), gcstats::PhaseKind::MARK_ROOTS);
+ DebugAPI::traceAllForMovingGC(&mover);
+ }
+ endProfile(ProfileKey::MarkDebugger);
+}
+
+size_t js::Nursery::doPretenuring(JSRuntime* rt, JS::GCReason reason,
+ bool validPromotionRate,
+ double promotionRate) {
+ size_t sitesPretenured = pretenuringNursery.doPretenuring(
+ gc, reason, validPromotionRate, promotionRate, reportPretenuring_,
+ reportPretenuringThreshold_);
+
+ bool highPromotionRate =
+ validPromotionRate && promotionRate > tunables().pretenureThreshold();
+
+ bool pretenureStr = false;
+ bool pretenureBigInt = false;
+ if (tunables().attemptPretenuring()) {
+ // Should we check for pretenuring regardless of GCReason?
+ // Use 3MB as the threshold so the pretenuring can be applied on Android.
+ bool pretenureAll =
+ highPromotionRate && previousGC.nurseryUsedBytes >= 3 * 1024 * 1024;
+
+ pretenureStr =
+ pretenureAll ||
+ IsFullStoreBufferReason(reason, JS::GCReason::FULL_CELL_PTR_STR_BUFFER);
+ pretenureBigInt =
+ pretenureAll || IsFullStoreBufferReason(
+ reason, JS::GCReason::FULL_CELL_PTR_BIGINT_BUFFER);
+ }
+
+ mozilla::Maybe<AutoGCSession> session;
+ uint32_t numStringsTenured = 0;
+ uint32_t numNurseryStringRealmsDisabled = 0;
+ uint32_t numBigIntsTenured = 0;
+ uint32_t numNurseryBigIntRealmsDisabled = 0;
+ for (ZonesIter zone(gc, SkipAtoms); !zone.done(); zone.next()) {
+ // For some tests in JetStream2 and Kraken, the tenuredRate is high but the
+ // number of allocated strings is low. So we calculate the tenuredRate only
+ // if the number of string allocations is enough.
+ bool allocThreshold = zone->nurseryAllocatedStrings > 30000;
+ uint64_t zoneTenuredStrings =
+ zone->stringStats.ref().liveNurseryStrings -
+ zone->previousGCStringStats.ref().liveNurseryStrings;
+ double tenuredRate =
+ allocThreshold
+ ? double(zoneTenuredStrings) / double(zone->nurseryAllocatedStrings)
+ : 0.0;
+ bool disableNurseryStrings =
+ pretenureStr && zone->allocNurseryStrings &&
+ tenuredRate > tunables().pretenureStringThreshold();
+ bool disableNurseryBigInts = pretenureBigInt && zone->allocNurseryBigInts &&
+ zone->tenuredBigInts >= 30 * 1000;
+ if (disableNurseryStrings || disableNurseryBigInts) {
+ if (!session.isSome()) {
+ session.emplace(gc, JS::HeapState::MinorCollecting);
+ }
+ CancelOffThreadIonCompile(zone);
+ bool preserving = zone->isPreservingCode();
+ zone->setPreservingCode(false);
+ zone->discardJitCode(rt->gcContext());
+ zone->setPreservingCode(preserving);
+ for (RealmsInZoneIter r(zone); !r.done(); r.next()) {
+ if (jit::JitRealm* jitRealm = r->jitRealm()) {
+ jitRealm->discardStubs();
+ if (disableNurseryStrings) {
+ jitRealm->setStringsCanBeInNursery(false);
+ numNurseryStringRealmsDisabled++;
+ }
+ if (disableNurseryBigInts) {
+ numNurseryBigIntRealmsDisabled++;
+ }
+ }
+ }
+ if (disableNurseryStrings) {
+ zone->allocNurseryStrings = false;
+ }
+ if (disableNurseryBigInts) {
+ zone->allocNurseryBigInts = false;
+ }
+ }
+ numStringsTenured += zoneTenuredStrings;
+ numBigIntsTenured += zone->tenuredBigInts;
+ zone->tenuredBigInts = 0;
+ zone->nurseryAllocatedStrings = 0;
+ }
+ session.reset(); // End the minor GC session, if running one.
+ stats().setStat(gcstats::STAT_NURSERY_STRING_REALMS_DISABLED,
+ numNurseryStringRealmsDisabled);
+ stats().setStat(gcstats::STAT_STRINGS_TENURED, numStringsTenured);
+ stats().setStat(gcstats::STAT_NURSERY_BIGINT_REALMS_DISABLED,
+ numNurseryBigIntRealmsDisabled);
+ stats().setStat(gcstats::STAT_BIGINTS_TENURED, numBigIntsTenured);
+
+ return sitesPretenured;
+}
+
+bool js::Nursery::registerMallocedBuffer(void* buffer, size_t nbytes) {
+ MOZ_ASSERT(buffer);
+ MOZ_ASSERT(nbytes > 0);
+ if (!mallocedBuffers.putNew(buffer)) {
+ return false;
+ }
+
+ mallocedBufferBytes += nbytes;
+ if (MOZ_UNLIKELY(mallocedBufferBytes > capacity() * 8)) {
+ requestMinorGC(JS::GCReason::NURSERY_MALLOC_BUFFERS);
+ }
+
+ return true;
+}
+
+void js::Nursery::sweep() {
+ // It's important that the context's GCUse is not Finalizing at this point,
+ // otherwise we will miscount memory attached to nursery objects with
+ // CellAllocPolicy.
+ AutoSetThreadIsSweeping setThreadSweeping(runtime()->gcContext());
+
+ MinorSweepingTracer trc(runtime());
+
+ // Sweep unique IDs first before we sweep any tables that may be keyed based
+ // on them.
+ for (Cell* cell : cellsWithUid_) {
+ auto* obj = static_cast<JSObject*>(cell);
+ if (!IsForwarded(obj)) {
+ obj->nurseryZone()->removeUniqueId(obj);
+ } else {
+ JSObject* dst = Forwarded(obj);
+ obj->nurseryZone()->transferUniqueId(dst, obj);
+ }
+ }
+ cellsWithUid_.clear();
+
+ for (ZonesIter zone(runtime(), SkipAtoms); !zone.done(); zone.next()) {
+ zone->sweepAfterMinorGC(&trc);
+ }
+
+ sweepMapAndSetObjects();
+
+ runtime()->caches().sweepAfterMinorGC(&trc);
+}
+
+void js::Nursery::clear() {
+ // Poison the nursery contents so touching a freed object will crash.
+ unsigned firstClearChunk;
+ if (gc->hasZealMode(ZealMode::GenerationalGC)) {
+ // Poison all the chunks used in this cycle. The new start chunk is
+ // reposioned in Nursery::collect() but there's no point optimising that in
+ // this case.
+ firstClearChunk = currentStartChunk_;
+ } else {
+ // In normal mode we start at the second chunk, the first one will be used
+ // in the next cycle and poisoned in Nusery::collect();
+ MOZ_ASSERT(currentStartChunk_ == 0);
+ firstClearChunk = 1;
+ }
+ for (unsigned i = firstClearChunk; i < currentChunk_; ++i) {
+ chunk(i).poisonAfterEvict();
+ }
+ // Clear only the used part of the chunk because that's the part we touched,
+ // but only if it's not going to be re-used immediately (>= firstClearChunk).
+ if (currentChunk_ >= firstClearChunk) {
+ chunk(currentChunk_)
+ .poisonAfterEvict(position() - chunk(currentChunk_).start());
+ }
+
+ // Reset the start chunk & position if we're not in this zeal mode, or we're
+ // in it and close to the end of the nursery.
+ MOZ_ASSERT(maxChunkCount() > 0);
+ if (!gc->hasZealMode(ZealMode::GenerationalGC) ||
+ (gc->hasZealMode(ZealMode::GenerationalGC) &&
+ currentChunk_ + 1 == maxChunkCount())) {
+ setCurrentChunk(0);
+ }
+
+ // Set current start position for isEmpty checks.
+ setStartPosition();
+}
+
+size_t js::Nursery::spaceToEnd(unsigned chunkCount) const {
+ if (chunkCount == 0) {
+ return 0;
+ }
+
+ unsigned lastChunk = chunkCount - 1;
+
+ MOZ_ASSERT(lastChunk >= currentStartChunk_);
+ MOZ_ASSERT(currentStartPosition_ - chunk(currentStartChunk_).start() <=
+ NurseryChunkUsableSize);
+
+ size_t bytes;
+
+ if (chunkCount != 1) {
+ // In the general case we have to add:
+ // + the bytes used in the first
+ // chunk which may be less than the total size of a chunk since in some
+ // zeal modes we start the first chunk at some later position
+ // (currentStartPosition_).
+ // + the size of all the other chunks.
+ bytes = (chunk(currentStartChunk_).end() - currentStartPosition_) +
+ ((lastChunk - currentStartChunk_) * ChunkSize);
+ } else {
+ // In sub-chunk mode, but it also works whenever chunkCount == 1, we need to
+ // use currentEnd_ since it may not refer to a full chunk.
+ bytes = currentEnd_ - currentStartPosition_;
+ }
+
+ MOZ_ASSERT(bytes <= maxChunkCount() * ChunkSize);
+
+ return bytes;
+}
+
+MOZ_ALWAYS_INLINE void js::Nursery::setCurrentChunk(unsigned chunkno) {
+ MOZ_ASSERT(chunkno < allocatedChunkCount());
+
+ currentChunk_ = chunkno;
+ position_ = chunk(chunkno).start();
+ setCurrentEnd();
+}
+
+void js::Nursery::poisonAndInitCurrentChunk(size_t extent) {
+ if (gc->hasZealMode(ZealMode::GenerationalGC) || !isSubChunkMode()) {
+ chunk(currentChunk_).poisonAndInit(runtime());
+ } else {
+ extent = std::min(capacity_, extent);
+ chunk(currentChunk_).poisonAndInit(runtime(), extent);
+ }
+}
+
+MOZ_ALWAYS_INLINE void js::Nursery::setCurrentEnd() {
+ MOZ_ASSERT_IF(isSubChunkMode(),
+ currentChunk_ == 0 && currentEnd_ <= chunk(0).end());
+ currentEnd_ =
+ uintptr_t(&chunk(currentChunk_)) + std::min(capacity_, ChunkSize);
+ if (canAllocateStrings_) {
+ currentStringEnd_ = currentEnd_;
+ }
+ if (canAllocateBigInts_) {
+ currentBigIntEnd_ = currentEnd_;
+ }
+}
+
+bool js::Nursery::allocateNextChunk(const unsigned chunkno,
+ AutoLockGCBgAlloc& lock) {
+ const unsigned priorCount = allocatedChunkCount();
+ const unsigned newCount = priorCount + 1;
+
+ MOZ_ASSERT((chunkno == currentChunk_ + 1) ||
+ (chunkno == 0 && allocatedChunkCount() == 0));
+ MOZ_ASSERT(chunkno == allocatedChunkCount());
+ MOZ_ASSERT(chunkno < HowMany(capacity(), ChunkSize));
+
+ if (!chunks_.resize(newCount)) {
+ return false;
+ }
+
+ TenuredChunk* newChunk;
+ newChunk = gc->getOrAllocChunk(lock);
+ if (!newChunk) {
+ chunks_.shrinkTo(priorCount);
+ return false;
+ }
+
+ chunks_[chunkno] = NurseryChunk::fromChunk(newChunk);
+ return true;
+}
+
+MOZ_ALWAYS_INLINE void js::Nursery::setStartPosition() {
+ currentStartChunk_ = currentChunk_;
+ currentStartPosition_ = position();
+}
+
+void js::Nursery::maybeResizeNursery(JS::GCOptions options,
+ JS::GCReason reason) {
+#ifdef JS_GC_ZEAL
+ // This zeal mode disabled nursery resizing.
+ if (gc->hasZealMode(ZealMode::GenerationalGC)) {
+ return;
+ }
+#endif
+
+ decommitTask.join();
+
+ size_t newCapacity = mozilla::Clamp(targetSize(options, reason),
+ tunables().gcMinNurseryBytes(),
+ tunables().gcMaxNurseryBytes());
+
+ MOZ_ASSERT(roundSize(newCapacity) == newCapacity);
+
+ if (newCapacity > capacity()) {
+ growAllocableSpace(newCapacity);
+ } else if (newCapacity < capacity()) {
+ shrinkAllocableSpace(newCapacity);
+ }
+
+ AutoLockHelperThreadState lock;
+ if (!decommitTask.isEmpty(lock)) {
+ decommitTask.startOrRunIfIdle(lock);
+ }
+}
+
+static inline bool ClampDouble(double* value, double min, double max) {
+ MOZ_ASSERT(!std::isnan(*value) && !std::isnan(min) && !std::isnan(max));
+ MOZ_ASSERT(max >= min);
+
+ if (*value <= min) {
+ *value = min;
+ return true;
+ }
+
+ if (*value >= max) {
+ *value = max;
+ return true;
+ }
+
+ return false;
+}
+
+size_t js::Nursery::targetSize(JS::GCOptions options, JS::GCReason reason) {
+ // Shrink the nursery as much as possible if purging was requested or in low
+ // memory situations.
+ if (options == JS::GCOptions::Shrink || gc::IsOOMReason(reason) ||
+ gc->systemHasLowMemory()) {
+ clearRecentGrowthData();
+ return 0;
+ }
+
+ // Don't resize the nursery during shutdown.
+ if (options == JS::GCOptions::Shutdown) {
+ clearRecentGrowthData();
+ return capacity();
+ }
+
+ TimeStamp now = TimeStamp::Now();
+
+ // If the nursery is completely unused then minimise it.
+ if (hasRecentGrowthData && previousGC.nurseryUsedBytes == 0 &&
+ now - lastCollectionEndTime() >
+ tunables().nurseryTimeoutForIdleCollection() &&
+ !js::SupportDifferentialTesting()) {
+ clearRecentGrowthData();
+ return 0;
+ }
+
+ // Calculate the fraction of the nursery promoted out of its entire
+ // capacity. This gives better results than using the promotion rate (based on
+ // the amount of nursery used) in cases where we collect before the nursery is
+ // full.
+ double fractionPromoted =
+ double(previousGC.tenuredBytes) / double(previousGC.nurseryCapacity);
+
+ // Calculate the duty factor, the fraction of time spent collecting the
+ // nursery.
+ double dutyFactor = 0.0;
+ TimeDuration collectorTime = now - collectionStartTime();
+ if (hasRecentGrowthData && !js::SupportDifferentialTesting()) {
+ TimeDuration totalTime = now - lastCollectionEndTime();
+ dutyFactor = collectorTime.ToSeconds() / totalTime.ToSeconds();
+ }
+
+ // Calculate a growth factor to try to achieve target promotion rate and duty
+ // factor goals.
+ static const double PromotionGoal = 0.02;
+ static const double DutyFactorGoal = 0.01;
+ double promotionGrowth = fractionPromoted / PromotionGoal;
+ double dutyGrowth = dutyFactor / DutyFactorGoal;
+ double growthFactor = std::max(promotionGrowth, dutyGrowth);
+
+ // Decrease the growth factor to try to keep collections shorter than a target
+ // maximum time. Don't do this during page load.
+ static const double MaxTimeGoalMs = 4.0;
+ if (!gc->isInPageLoad() && !js::SupportDifferentialTesting()) {
+ double timeGrowth = MaxTimeGoalMs / collectorTime.ToMilliseconds();
+ growthFactor = std::min(growthFactor, timeGrowth);
+ }
+
+ // Limit the range of the growth factor to prevent transient high promotion
+ // rates from affecting the nursery size too far into the future.
+ static const double GrowthRange = 2.0;
+ bool wasClamped = ClampDouble(&growthFactor, 1.0 / GrowthRange, GrowthRange);
+
+ // Calculate the target size based on data from this collection.
+ double target = double(capacity()) * growthFactor;
+
+ // Use exponential smoothing on the target size to take into account data from
+ // recent previous collections.
+ if (hasRecentGrowthData &&
+ now - lastCollectionEndTime() < TimeDuration::FromMilliseconds(200) &&
+ !js::SupportDifferentialTesting()) {
+ // Pay more attention to large changes.
+ double fraction = wasClamped ? 0.5 : 0.25;
+ smoothedTargetSize =
+ (1 - fraction) * smoothedTargetSize + fraction * target;
+ } else {
+ smoothedTargetSize = target;
+ }
+ hasRecentGrowthData = true;
+
+ // Leave size untouched if we are close to the target.
+ static const double GoalWidth = 1.5;
+ growthFactor = smoothedTargetSize / double(capacity());
+ if (growthFactor > (1.0 / GoalWidth) && growthFactor < GoalWidth) {
+ return capacity();
+ }
+
+ return roundSize(size_t(smoothedTargetSize));
+}
+
+void js::Nursery::clearRecentGrowthData() {
+ if (js::SupportDifferentialTesting()) {
+ return;
+ }
+
+ hasRecentGrowthData = false;
+ smoothedTargetSize = 0.0;
+}
+
+/* static */
+size_t js::Nursery::roundSize(size_t size) {
+ size_t step = size >= ChunkSize ? ChunkSize : SystemPageSize();
+ size = Round(size, step);
+
+ MOZ_ASSERT(size >= SystemPageSize());
+
+ return size;
+}
+
+void js::Nursery::growAllocableSpace(size_t newCapacity) {
+ MOZ_ASSERT_IF(!isSubChunkMode(), newCapacity > currentChunk_ * ChunkSize);
+ MOZ_ASSERT(newCapacity <= tunables().gcMaxNurseryBytes());
+ MOZ_ASSERT(newCapacity > capacity());
+
+ if (!decommitTask.reserveSpaceForBytes(newCapacity)) {
+ return;
+ }
+
+ if (isSubChunkMode()) {
+ MOZ_ASSERT(currentChunk_ == 0);
+
+ // The remainder of the chunk may have been decommitted.
+ if (!chunk(0).markPagesInUseHard(std::min(newCapacity, ChunkSize))) {
+ // The OS won't give us the memory we need, we can't grow.
+ return;
+ }
+
+ // The capacity has changed and since we were in sub-chunk mode we need to
+ // update the poison values / asan information for the now-valid region of
+ // this chunk.
+ size_t size = std::min(newCapacity, ChunkSize) - capacity();
+ chunk(0).poisonRange(capacity(), size, JS_FRESH_NURSERY_PATTERN,
+ MemCheckKind::MakeUndefined);
+ }
+
+ capacity_ = newCapacity;
+
+ setCurrentEnd();
+}
+
+void js::Nursery::freeChunksFrom(const unsigned firstFreeChunk) {
+ MOZ_ASSERT(firstFreeChunk < chunks_.length());
+
+ // The loop below may need to skip the first chunk, so we may use this so we
+ // can modify it.
+ unsigned firstChunkToDecommit = firstFreeChunk;
+
+ if ((firstChunkToDecommit == 0) && isSubChunkMode()) {
+ // Part of the first chunk may be hard-decommitted, un-decommit it so that
+ // the GC's normal chunk-handling doesn't segfault.
+ MOZ_ASSERT(currentChunk_ == 0);
+ if (!chunk(0).markPagesInUseHard(ChunkSize)) {
+ // Free the chunk if we can't allocate its pages.
+ UnmapPages(static_cast<void*>(&chunk(0)), ChunkSize);
+ firstChunkToDecommit = 1;
+ }
+ }
+
+ {
+ AutoLockHelperThreadState lock;
+ for (size_t i = firstChunkToDecommit; i < chunks_.length(); i++) {
+ decommitTask.queueChunk(chunks_[i], lock);
+ }
+ }
+
+ chunks_.shrinkTo(firstFreeChunk);
+}
+
+void js::Nursery::shrinkAllocableSpace(size_t newCapacity) {
+#ifdef JS_GC_ZEAL
+ if (gc->hasZealMode(ZealMode::GenerationalGC)) {
+ return;
+ }
+#endif
+
+ // Don't shrink the nursery to zero (use Nursery::disable() instead)
+ // This can't happen due to the rounding-down performed above because of the
+ // clamping in maybeResizeNursery().
+ MOZ_ASSERT(newCapacity != 0);
+ // Don't attempt to shrink it to the same size.
+ if (newCapacity == capacity_) {
+ return;
+ }
+ MOZ_ASSERT(newCapacity < capacity_);
+
+ unsigned newCount = HowMany(newCapacity, ChunkSize);
+ if (newCount < allocatedChunkCount()) {
+ freeChunksFrom(newCount);
+ }
+
+ size_t oldCapacity = capacity_;
+ capacity_ = newCapacity;
+
+ setCurrentEnd();
+
+ if (isSubChunkMode()) {
+ MOZ_ASSERT(currentChunk_ == 0);
+ size_t size = std::min(oldCapacity, ChunkSize) - newCapacity;
+ chunk(0).poisonRange(newCapacity, size, JS_SWEPT_NURSERY_PATTERN,
+ MemCheckKind::MakeNoAccess);
+
+ AutoLockHelperThreadState lock;
+ decommitTask.queueRange(capacity_, chunk(0), lock);
+ }
+}
+
+uintptr_t js::Nursery::currentEnd() const {
+ // These are separate asserts because it can be useful to see which one
+ // failed.
+ MOZ_ASSERT_IF(isSubChunkMode(), currentChunk_ == 0);
+ MOZ_ASSERT_IF(isSubChunkMode(), currentEnd_ <= chunk(currentChunk_).end());
+ MOZ_ASSERT_IF(!isSubChunkMode(), currentEnd_ == chunk(currentChunk_).end());
+ MOZ_ASSERT(currentEnd_ != chunk(currentChunk_).start());
+ return currentEnd_;
+}
+
+gcstats::Statistics& js::Nursery::stats() const { return gc->stats(); }
+
+MOZ_ALWAYS_INLINE const js::gc::GCSchedulingTunables& js::Nursery::tunables()
+ const {
+ return gc->tunables;
+}
+
+bool js::Nursery::isSubChunkMode() const {
+ return capacity() <= NurseryChunkUsableSize;
+}
+
+void js::Nursery::sweepMapAndSetObjects() {
+ auto gcx = runtime()->gcContext();
+
+ for (auto mapobj : mapsWithNurseryMemory_) {
+ MapObject::sweepAfterMinorGC(gcx, mapobj);
+ }
+ mapsWithNurseryMemory_.clearAndFree();
+
+ for (auto setobj : setsWithNurseryMemory_) {
+ SetObject::sweepAfterMinorGC(gcx, setobj);
+ }
+ setsWithNurseryMemory_.clearAndFree();
+}
+
+JS_PUBLIC_API void JS::EnableNurseryStrings(JSContext* cx) {
+ AutoEmptyNursery empty(cx);
+ ReleaseAllJITCode(cx->gcContext());
+ cx->runtime()->gc.nursery().enableStrings();
+}
+
+JS_PUBLIC_API void JS::DisableNurseryStrings(JSContext* cx) {
+ AutoEmptyNursery empty(cx);
+ ReleaseAllJITCode(cx->gcContext());
+ cx->runtime()->gc.nursery().disableStrings();
+}
+
+JS_PUBLIC_API void JS::EnableNurseryBigInts(JSContext* cx) {
+ AutoEmptyNursery empty(cx);
+ ReleaseAllJITCode(cx->gcContext());
+ cx->runtime()->gc.nursery().enableBigInts();
+}
+
+JS_PUBLIC_API void JS::DisableNurseryBigInts(JSContext* cx) {
+ AutoEmptyNursery empty(cx);
+ ReleaseAllJITCode(cx->gcContext());
+ cx->runtime()->gc.nursery().disableBigInts();
+}
generated by cgit v1.2.3 (git 2.39.1) at 2024-11-29 03:35:03 +0000