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+// Copyright 2017 The Abseil Authors.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+// A low-level allocator that can be used by other low-level
+// modules without introducing dependency cycles.
+// This allocator is slow and wasteful of memory;
+// it should not be used when performance is key.
+
+#include "absl/base/config.h"
+
+#include "absl/base/internal/low_level_alloc.h"
+
+// LowLevelAlloc requires that the platform support low-level
+// allocation of virtual memory. Platforms lacking this cannot use
+// LowLevelAlloc.
+#ifndef ABSL_LOW_LEVEL_ALLOC_MISSING
+
+#ifndef _WIN32
+#include <pthread.h>
+#include <signal.h>
+#include <sys/mman.h>
+#include <unistd.h>
+#else
+#include <windows.h>
+#endif
+
+#include <string.h>
+#include <algorithm>
+#include <atomic>
+#include <cstddef>
+#include <cerrno>
+#include <new> // for placement-new
+
+#include "absl/base/dynamic_annotations.h"
+#include "absl/base/internal/malloc_hook.h"
+#include "absl/base/internal/malloc_hook_invoke.h"
+#include "absl/base/internal/raw_logging.h"
+#include "absl/base/internal/spinlock.h"
+
+// MAP_ANONYMOUS
+#if defined(__APPLE__)
+// For mmap, Linux defines both MAP_ANONYMOUS and MAP_ANON and says MAP_ANON is
+// deprecated. In Darwin, MAP_ANON is all there is.
+#if !defined MAP_ANONYMOUS
+#define MAP_ANONYMOUS MAP_ANON
+#endif // !MAP_ANONYMOUS
+#endif // __APPLE__
+
+namespace absl {
+namespace base_internal {
+
+// A first-fit allocator with amortized logarithmic free() time.
+
+// ---------------------------------------------------------------------------
+static const int kMaxLevel = 30;
+
+namespace {
+// This struct describes one allocated block, or one free block.
+struct AllocList {
+ struct Header {
+ // Size of entire region, including this field. Must be
+ // first. Valid in both allocated and unallocated blocks.
+ uintptr_t size;
+
+ // kMagicAllocated or kMagicUnallocated xor this.
+ uintptr_t magic;
+
+ // Pointer to parent arena.
+ LowLevelAlloc::Arena *arena;
+
+ // Aligns regions to 0 mod 2*sizeof(void*).
+ void *dummy_for_alignment;
+ } header;
+
+ // Next two fields: in unallocated blocks: freelist skiplist data
+ // in allocated blocks: overlaps with client data
+
+ // Levels in skiplist used.
+ int levels;
+
+ // Actually has levels elements. The AllocList node may not have room
+ // for all kMaxLevel entries. See max_fit in LLA_SkiplistLevels().
+ AllocList *next[kMaxLevel];
+};
+} // namespace
+
+// ---------------------------------------------------------------------------
+// A trivial skiplist implementation. This is used to keep the freelist
+// in address order while taking only logarithmic time per insert and delete.
+
+// An integer approximation of log2(size/base)
+// Requires size >= base.
+static int IntLog2(size_t size, size_t base) {
+ int result = 0;
+ for (size_t i = size; i > base; i >>= 1) { // i == floor(size/2**result)
+ result++;
+ }
+ // floor(size / 2**result) <= base < floor(size / 2**(result-1))
+ // => log2(size/(base+1)) <= result < 1+log2(size/base)
+ // => result ~= log2(size/base)
+ return result;
+}
+
+// Return a random integer n: p(n)=1/(2**n) if 1 <= n; p(n)=0 if n < 1.
+static int Random(uint32_t *state) {
+ uint32_t r = *state;
+ int result = 1;
+ while ((((r = r*1103515245 + 12345) >> 30) & 1) == 0) {
+ result++;
+ }
+ *state = r;
+ return result;
+}
+
+// Return a number of skiplist levels for a node of size bytes, where
+// base is the minimum node size. Compute level=log2(size / base)+n
+// where n is 1 if random is false and otherwise a random number generated with
+// the standard distribution for a skiplist: See Random() above.
+// Bigger nodes tend to have more skiplist levels due to the log2(size / base)
+// term, so first-fit searches touch fewer nodes. "level" is clipped so
+// level<kMaxLevel and next[level-1] will fit in the node.
+// 0 < LLA_SkiplistLevels(x,y,false) <= LLA_SkiplistLevels(x,y,true) < kMaxLevel
+static int LLA_SkiplistLevels(size_t size, size_t base, uint32_t *random) {
+ // max_fit is the maximum number of levels that will fit in a node for the
+ // given size. We can't return more than max_fit, no matter what the
+ // random number generator says.
+ size_t max_fit = (size - offsetof(AllocList, next)) / sizeof(AllocList *);
+ int level = IntLog2(size, base) + (random != nullptr ? Random(random) : 1);
+ if (static_cast<size_t>(level) > max_fit) level = static_cast<int>(max_fit);
+ if (level > kMaxLevel-1) level = kMaxLevel - 1;
+ ABSL_RAW_CHECK(level >= 1, "block not big enough for even one level");
+ return level;
+}
+
+// Return "atleast", the first element of AllocList *head s.t. *atleast >= *e.
+// For 0 <= i < head->levels, set prev[i] to "no_greater", where no_greater
+// points to the last element at level i in the AllocList less than *e, or is
+// head if no such element exists.
+static AllocList *LLA_SkiplistSearch(AllocList *head,
+ AllocList *e, AllocList **prev) {
+ AllocList *p = head;
+ for (int level = head->levels - 1; level >= 0; level--) {
+ for (AllocList *n; (n = p->next[level]) != nullptr && n < e; p = n) {
+ }
+ prev[level] = p;
+ }
+ return (head->levels == 0) ? nullptr : prev[0]->next[0];
+}
+
+// Insert element *e into AllocList *head. Set prev[] as LLA_SkiplistSearch.
+// Requires that e->levels be previously set by the caller (using
+// LLA_SkiplistLevels())
+static void LLA_SkiplistInsert(AllocList *head, AllocList *e,
+ AllocList **prev) {
+ LLA_SkiplistSearch(head, e, prev);
+ for (; head->levels < e->levels; head->levels++) { // extend prev pointers
+ prev[head->levels] = head; // to all *e's levels
+ }
+ for (int i = 0; i != e->levels; i++) { // add element to list
+ e->next[i] = prev[i]->next[i];
+ prev[i]->next[i] = e;
+ }
+}
+
+// Remove element *e from AllocList *head. Set prev[] as LLA_SkiplistSearch().
+// Requires that e->levels be previous set by the caller (using
+// LLA_SkiplistLevels())
+static void LLA_SkiplistDelete(AllocList *head, AllocList *e,
+ AllocList **prev) {
+ AllocList *found = LLA_SkiplistSearch(head, e, prev);
+ ABSL_RAW_CHECK(e == found, "element not in freelist");
+ for (int i = 0; i != e->levels && prev[i]->next[i] == e; i++) {
+ prev[i]->next[i] = e->next[i];
+ }
+ while (head->levels > 0 && head->next[head->levels - 1] == nullptr) {
+ head->levels--; // reduce head->levels if level unused
+ }
+}
+
+// ---------------------------------------------------------------------------
+// Arena implementation
+
+struct LowLevelAlloc::Arena {
+ // This constructor does nothing, and relies on zero-initialization to get
+ // the proper initial state.
+ Arena() : mu(base_internal::kLinkerInitialized) {} // NOLINT
+ explicit Arena(int) // NOLINT(readability/casting)
+ : // Avoid recursive cooperative scheduling w/ kernel scheduling.
+ mu(base_internal::SCHEDULE_KERNEL_ONLY),
+ // Set pagesize to zero explicitly for non-static init.
+ pagesize(0),
+ random(0) {}
+
+ base_internal::SpinLock mu; // protects freelist, allocation_count,
+ // pagesize, roundup, min_size
+ AllocList freelist; // head of free list; sorted by addr (under mu)
+ int32_t allocation_count; // count of allocated blocks (under mu)
+ std::atomic<uint32_t> flags; // flags passed to NewArena (ro after init)
+ size_t pagesize; // ==getpagesize() (init under mu, then ro)
+ size_t roundup; // lowest 2^n >= max(16,sizeof (AllocList))
+ // (init under mu, then ro)
+ size_t min_size; // smallest allocation block size
+ // (init under mu, then ro)
+ uint32_t random; // PRNG state
+};
+
+// The default arena, which is used when 0 is passed instead of an Arena
+// pointer.
+static struct LowLevelAlloc::Arena default_arena; // NOLINT
+
+// Non-malloc-hooked arenas: used only to allocate metadata for arenas that
+// do not want malloc hook reporting, so that for them there's no malloc hook
+// reporting even during arena creation.
+static struct LowLevelAlloc::Arena unhooked_arena; // NOLINT
+
+#ifndef ABSL_LOW_LEVEL_ALLOC_ASYNC_SIGNAL_SAFE_MISSING
+static struct LowLevelAlloc::Arena unhooked_async_sig_safe_arena; // NOLINT
+#endif
+
+// magic numbers to identify allocated and unallocated blocks
+static const uintptr_t kMagicAllocated = 0x4c833e95U;
+static const uintptr_t kMagicUnallocated = ~kMagicAllocated;
+
+namespace {
+class SCOPED_LOCKABLE ArenaLock {
+ public:
+ explicit ArenaLock(LowLevelAlloc::Arena *arena)
+ EXCLUSIVE_LOCK_FUNCTION(arena->mu)
+ : arena_(arena) {
+#ifndef ABSL_LOW_LEVEL_ALLOC_ASYNC_SIGNAL_SAFE_MISSING
+ if (arena == &unhooked_async_sig_safe_arena ||
+ (arena->flags.load(std::memory_order_relaxed) &
+ LowLevelAlloc::kAsyncSignalSafe) != 0) {
+ sigset_t all;
+ sigfillset(&all);
+ mask_valid_ = pthread_sigmask(SIG_BLOCK, &all, &mask_) == 0;
+ }
+#endif
+ arena_->mu.Lock();
+ }
+ ~ArenaLock() { ABSL_RAW_CHECK(left_, "haven't left Arena region"); }
+ void Leave() UNLOCK_FUNCTION() {
+ arena_->mu.Unlock();
+#ifndef ABSL_LOW_LEVEL_ALLOC_ASYNC_SIGNAL_SAFE_MISSING
+ if (mask_valid_) {
+ pthread_sigmask(SIG_SETMASK, &mask_, nullptr);
+ }
+#endif
+ left_ = true;
+ }
+
+ private:
+ bool left_ = false; // whether left region
+#ifndef ABSL_LOW_LEVEL_ALLOC_ASYNC_SIGNAL_SAFE_MISSING
+ bool mask_valid_ = false;
+ sigset_t mask_; // old mask of blocked signals
+#endif
+ LowLevelAlloc::Arena *arena_;
+ ArenaLock(const ArenaLock &) = delete;
+ ArenaLock &operator=(const ArenaLock &) = delete;
+};
+} // namespace
+
+// create an appropriate magic number for an object at "ptr"
+// "magic" should be kMagicAllocated or kMagicUnallocated
+inline static uintptr_t Magic(uintptr_t magic, AllocList::Header *ptr) {
+ return magic ^ reinterpret_cast<uintptr_t>(ptr);
+}
+
+// Initialize the fields of an Arena
+static void ArenaInit(LowLevelAlloc::Arena *arena) {
+ if (arena->pagesize == 0) {
+#ifdef _WIN32
+ SYSTEM_INFO system_info;
+ GetSystemInfo(&system_info);
+ arena->pagesize = std::max(system_info.dwPageSize,
+ system_info.dwAllocationGranularity);
+#else
+ arena->pagesize = getpagesize();
+#endif
+ // Round up block sizes to a power of two close to the header size.
+ arena->roundup = 16;
+ while (arena->roundup < sizeof (arena->freelist.header)) {
+ arena->roundup += arena->roundup;
+ }
+ // Don't allocate blocks less than twice the roundup size to avoid tiny
+ // free blocks.
+ arena->min_size = 2 * arena->roundup;
+ arena->freelist.header.size = 0;
+ arena->freelist.header.magic =
+ Magic(kMagicUnallocated, &arena->freelist.header);
+ arena->freelist.header.arena = arena;
+ arena->freelist.levels = 0;
+ memset(arena->freelist.next, 0, sizeof (arena->freelist.next));
+ arena->allocation_count = 0;
+ if (arena == &default_arena) {
+ // Default arena should be hooked, e.g. for heap-checker to trace
+ // pointer chains through objects in the default arena.
+ arena->flags.store(LowLevelAlloc::kCallMallocHook,
+ std::memory_order_relaxed);
+ }
+#ifndef ABSL_LOW_LEVEL_ALLOC_ASYNC_SIGNAL_SAFE_MISSING
+ else if (arena == // NOLINT(readability/braces)
+ &unhooked_async_sig_safe_arena) {
+ arena->flags.store(LowLevelAlloc::kAsyncSignalSafe,
+ std::memory_order_relaxed);
+ }
+#endif
+ else { // NOLINT(readability/braces)
+ // other arenas' flags may be overridden by client,
+ // but unhooked_arena will have 0 in 'flags'.
+ arena->flags.store(0, std::memory_order_relaxed);
+ }
+ }
+}
+
+// L < meta_data_arena->mu
+LowLevelAlloc::Arena *LowLevelAlloc::NewArena(int32_t flags,
+ Arena *meta_data_arena) {
+ ABSL_RAW_CHECK(meta_data_arena != nullptr, "must pass a valid arena");
+ if (meta_data_arena == &default_arena) {
+#ifndef ABSL_LOW_LEVEL_ALLOC_ASYNC_SIGNAL_SAFE_MISSING
+ if ((flags & LowLevelAlloc::kAsyncSignalSafe) != 0) {
+ meta_data_arena = &unhooked_async_sig_safe_arena;
+ } else // NOLINT(readability/braces)
+#endif
+ if ((flags & LowLevelAlloc::kCallMallocHook) == 0) {
+ meta_data_arena = &unhooked_arena;
+ }
+ }
+ // Arena(0) uses the constructor for non-static contexts
+ Arena *result =
+ new (AllocWithArena(sizeof (*result), meta_data_arena)) Arena(0);
+ ArenaInit(result);
+ result->flags.store(flags, std::memory_order_relaxed);
+ return result;
+}
+
+// L < arena->mu, L < arena->arena->mu
+bool LowLevelAlloc::DeleteArena(Arena *arena) {
+ ABSL_RAW_CHECK(
+ arena != nullptr && arena != &default_arena && arena != &unhooked_arena,
+ "may not delete default arena");
+ ArenaLock section(arena);
+ bool empty = (arena->allocation_count == 0);
+ section.Leave();
+ if (empty) {
+ while (arena->freelist.next[0] != nullptr) {
+ AllocList *region = arena->freelist.next[0];
+ size_t size = region->header.size;
+ arena->freelist.next[0] = region->next[0];
+ ABSL_RAW_CHECK(
+ region->header.magic == Magic(kMagicUnallocated, &region->header),
+ "bad magic number in DeleteArena()");
+ ABSL_RAW_CHECK(region->header.arena == arena,
+ "bad arena pointer in DeleteArena()");
+ ABSL_RAW_CHECK(size % arena->pagesize == 0,
+ "empty arena has non-page-aligned block size");
+ ABSL_RAW_CHECK(reinterpret_cast<uintptr_t>(region) % arena->pagesize == 0,
+ "empty arena has non-page-aligned block");
+ int munmap_result;
+#ifdef _WIN32
+ munmap_result = VirtualFree(region, 0, MEM_RELEASE);
+ ABSL_RAW_CHECK(munmap_result != 0,
+ "LowLevelAlloc::DeleteArena: VitualFree failed");
+#else
+ if ((arena->flags.load(std::memory_order_relaxed) &
+ LowLevelAlloc::kAsyncSignalSafe) == 0) {
+ munmap_result = munmap(region, size);
+ } else {
+ munmap_result = MallocHook::UnhookedMUnmap(region, size);
+ }
+ if (munmap_result != 0) {
+ ABSL_RAW_LOG(FATAL, "LowLevelAlloc::DeleteArena: munmap failed: %d",
+ errno);
+ }
+#endif
+ }
+ Free(arena);
+ }
+ return empty;
+}
+
+// ---------------------------------------------------------------------------
+
+// Addition, checking for overflow. The intent is to die if an external client
+// manages to push through a request that would cause arithmetic to fail.
+static inline uintptr_t CheckedAdd(uintptr_t a, uintptr_t b) {
+ uintptr_t sum = a + b;
+ ABSL_RAW_CHECK(sum >= a, "LowLevelAlloc arithmetic overflow");
+ return sum;
+}
+
+// Return value rounded up to next multiple of align.
+// align must be a power of two.
+static inline uintptr_t RoundUp(uintptr_t addr, uintptr_t align) {
+ return CheckedAdd(addr, align - 1) & ~(align - 1);
+}
+
+// Equivalent to "return prev->next[i]" but with sanity checking
+// that the freelist is in the correct order, that it
+// consists of regions marked "unallocated", and that no two regions
+// are adjacent in memory (they should have been coalesced).
+// L < arena->mu
+static AllocList *Next(int i, AllocList *prev, LowLevelAlloc::Arena *arena) {
+ ABSL_RAW_CHECK(i < prev->levels, "too few levels in Next()");
+ AllocList *next = prev->next[i];
+ if (next != nullptr) {
+ ABSL_RAW_CHECK(
+ next->header.magic == Magic(kMagicUnallocated, &next->header),
+ "bad magic number in Next()");
+ ABSL_RAW_CHECK(next->header.arena == arena, "bad arena pointer in Next()");
+ if (prev != &arena->freelist) {
+ ABSL_RAW_CHECK(prev < next, "unordered freelist");
+ ABSL_RAW_CHECK(reinterpret_cast<char *>(prev) + prev->header.size <
+ reinterpret_cast<char *>(next),
+ "malformed freelist");
+ }
+ }
+ return next;
+}
+
+// Coalesce list item "a" with its successor if they are adjacent.
+static void Coalesce(AllocList *a) {
+ AllocList *n = a->next[0];
+ if (n != nullptr && reinterpret_cast<char *>(a) + a->header.size ==
+ reinterpret_cast<char *>(n)) {
+ LowLevelAlloc::Arena *arena = a->header.arena;
+ a->header.size += n->header.size;
+ n->header.magic = 0;
+ n->header.arena = nullptr;
+ AllocList *prev[kMaxLevel];
+ LLA_SkiplistDelete(&arena->freelist, n, prev);
+ LLA_SkiplistDelete(&arena->freelist, a, prev);
+ a->levels = LLA_SkiplistLevels(a->header.size, arena->min_size,
+ &arena->random);
+ LLA_SkiplistInsert(&arena->freelist, a, prev);
+ }
+}
+
+// Adds block at location "v" to the free list
+// L >= arena->mu
+static void AddToFreelist(void *v, LowLevelAlloc::Arena *arena) {
+ AllocList *f = reinterpret_cast<AllocList *>(
+ reinterpret_cast<char *>(v) - sizeof (f->header));
+ ABSL_RAW_CHECK(f->header.magic == Magic(kMagicAllocated, &f->header),
+ "bad magic number in AddToFreelist()");
+ ABSL_RAW_CHECK(f->header.arena == arena,
+ "bad arena pointer in AddToFreelist()");
+ f->levels = LLA_SkiplistLevels(f->header.size, arena->min_size,
+ &arena->random);
+ AllocList *prev[kMaxLevel];
+ LLA_SkiplistInsert(&arena->freelist, f, prev);
+ f->header.magic = Magic(kMagicUnallocated, &f->header);
+ Coalesce(f); // maybe coalesce with successor
+ Coalesce(prev[0]); // maybe coalesce with predecessor
+}
+
+// Frees storage allocated by LowLevelAlloc::Alloc().
+// L < arena->mu
+void LowLevelAlloc::Free(void *v) {
+ if (v != nullptr) {
+ AllocList *f = reinterpret_cast<AllocList *>(
+ reinterpret_cast<char *>(v) - sizeof (f->header));
+ ABSL_RAW_CHECK(f->header.magic == Magic(kMagicAllocated, &f->header),
+ "bad magic number in Free()");
+ LowLevelAlloc::Arena *arena = f->header.arena;
+ if ((arena->flags.load(std::memory_order_relaxed) & kCallMallocHook) != 0) {
+ MallocHook::InvokeDeleteHook(v);
+ }
+ ArenaLock section(arena);
+ AddToFreelist(v, arena);
+ ABSL_RAW_CHECK(arena->allocation_count > 0, "nothing in arena to free");
+ arena->allocation_count--;
+ section.Leave();
+ }
+}
+
+// allocates and returns a block of size bytes, to be freed with Free()
+// L < arena->mu
+static void *DoAllocWithArena(size_t request, LowLevelAlloc::Arena *arena) {
+ void *result = nullptr;
+ if (request != 0) {
+ AllocList *s; // will point to region that satisfies request
+ ArenaLock section(arena);
+ ArenaInit(arena);
+ // round up with header
+ size_t req_rnd = RoundUp(CheckedAdd(request, sizeof (s->header)),
+ arena->roundup);
+ for (;;) { // loop until we find a suitable region
+ // find the minimum levels that a block of this size must have
+ int i = LLA_SkiplistLevels(req_rnd, arena->min_size, nullptr) - 1;
+ if (i < arena->freelist.levels) { // potential blocks exist
+ AllocList *before = &arena->freelist; // predecessor of s
+ while ((s = Next(i, before, arena)) != nullptr &&
+ s->header.size < req_rnd) {
+ before = s;
+ }
+ if (s != nullptr) { // we found a region
+ break;
+ }
+ }
+ // we unlock before mmap() both because mmap() may call a callback hook,
+ // and because it may be slow.
+ arena->mu.Unlock();
+ // mmap generous 64K chunks to decrease
+ // the chances/impact of fragmentation:
+ size_t new_pages_size = RoundUp(req_rnd, arena->pagesize * 16);
+ void *new_pages;
+#ifdef _WIN32
+ new_pages = VirtualAlloc(0, new_pages_size,
+ MEM_RESERVE | MEM_COMMIT, PAGE_READWRITE);
+ ABSL_RAW_CHECK(new_pages != nullptr, "VirtualAlloc failed");
+#else
+ if ((arena->flags.load(std::memory_order_relaxed) &
+ LowLevelAlloc::kAsyncSignalSafe) != 0) {
+ new_pages = MallocHook::UnhookedMMap(nullptr, new_pages_size,
+ PROT_WRITE|PROT_READ, MAP_ANONYMOUS|MAP_PRIVATE, -1, 0);
+ } else {
+ new_pages = mmap(nullptr, new_pages_size, PROT_WRITE | PROT_READ,
+ MAP_ANONYMOUS | MAP_PRIVATE, -1, 0);
+ }
+ if (new_pages == MAP_FAILED) {
+ ABSL_RAW_LOG(FATAL, "mmap error: %d", errno);
+ }
+#endif
+ arena->mu.Lock();
+ s = reinterpret_cast<AllocList *>(new_pages);
+ s->header.size = new_pages_size;
+ // Pretend the block is allocated; call AddToFreelist() to free it.
+ s->header.magic = Magic(kMagicAllocated, &s->header);
+ s->header.arena = arena;
+ AddToFreelist(&s->levels, arena); // insert new region into free list
+ }
+ AllocList *prev[kMaxLevel];
+ LLA_SkiplistDelete(&arena->freelist, s, prev); // remove from free list
+ // s points to the first free region that's big enough
+ if (CheckedAdd(req_rnd, arena->min_size) <= s->header.size) {
+ // big enough to split
+ AllocList *n = reinterpret_cast<AllocList *>
+ (req_rnd + reinterpret_cast<char *>(s));
+ n->header.size = s->header.size - req_rnd;
+ n->header.magic = Magic(kMagicAllocated, &n->header);
+ n->header.arena = arena;
+ s->header.size = req_rnd;
+ AddToFreelist(&n->levels, arena);
+ }
+ s->header.magic = Magic(kMagicAllocated, &s->header);
+ ABSL_RAW_CHECK(s->header.arena == arena, "");
+ arena->allocation_count++;
+ section.Leave();
+ result = &s->levels;
+ }
+ ANNOTATE_MEMORY_IS_UNINITIALIZED(result, request);
+ return result;
+}
+
+void *LowLevelAlloc::Alloc(size_t request) {
+ void *result = DoAllocWithArena(request, &default_arena);
+ if ((default_arena.flags.load(std::memory_order_relaxed) &
+ kCallMallocHook) != 0) {
+ // this call must be directly in the user-called allocator function
+ // for MallocHook::GetCallerStackTrace to work properly
+ MallocHook::InvokeNewHook(result, request);
+ }
+ return result;
+}
+
+void *LowLevelAlloc::AllocWithArena(size_t request, Arena *arena) {
+ ABSL_RAW_CHECK(arena != nullptr, "must pass a valid arena");
+ void *result = DoAllocWithArena(request, arena);
+ if ((arena->flags.load(std::memory_order_relaxed) & kCallMallocHook) != 0) {
+ // this call must be directly in the user-called allocator function
+ // for MallocHook::GetCallerStackTrace to work properly
+ MallocHook::InvokeNewHook(result, request);
+ }
+ return result;
+}
+
+LowLevelAlloc::Arena *LowLevelAlloc::DefaultArena() {
+ return &default_arena;
+}
+
+} // namespace base_internal
+} // namespace absl
+
+#endif // ABSL_LOW_LEVEL_ALLOC_MISSING
generated by cgit v1.2.3 (git 2.39.1) at 2024-12-15 09:43:34 +0000