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Export of internal Abseil changes.

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--
821196cfb2a3b943ffdc4c9e75daec92d7ffb28b by Abseil Team <absl-team@google.com>:

Performance improvements

PiperOrigin-RevId: 212668992

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704858e2e767016bad27d53eec01d9d48e546b23 by Abseil Team <absl-team@google.com>:

Low-level Portability enchancements for Abseil Mutex on WebAssembly.

Emscripten Pthreads do not use signals, so remove use of pthread_sigmask or
other async-signal-safe related handling code.

PiperOrigin-RevId: 212527958

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be3e38cb4d493b755132d20c8c2d1a51e45d5449 by Jon Cohen <cohenjon@google.com>:

Internal change.

PiperOrigin-RevId: 212523797
GitOrigin-RevId: 821196cfb2a3b943ffdc4c9e75daec92d7ffb28b
Change-Id: I5694e23e4e09364a15dd6fc4e2e3f15e38835687
This commit is contained in:
Abseil Team 2018-09-12 11:03:25 -07:00 • committed by Gennadiy Civil
parent 02451914b9
commit 8ff1374008
9 changed files with 198 additions and 170 deletions
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14
absl/base/internal/low_level_alloc.cc
View file

@ -401,16 +401,20 @@ bool LowLevelAlloc::DeleteArena(Arena *arena) {
ABSL_RAW_CHECK(munmap_result != 0,
"LowLevelAlloc::DeleteArena: VitualFree failed");
#else
#ifndef ABSL_LOW_LEVEL_ALLOC_ASYNC_SIGNAL_SAFE_MISSING
if ((arena->flags & LowLevelAlloc::kAsyncSignalSafe) == 0) {
munmap_result = munmap(region, size);
} else {
munmap_result = base_internal::DirectMunmap(region, size);
}
#else
munmap_result = munmap(region, size);
#endif // ABSL_LOW_LEVEL_ALLOC_ASYNC_SIGNAL_SAFE_MISSING
if (munmap_result != 0) {
ABSL_RAW_LOG(FATAL, "LowLevelAlloc::DeleteArena: munmap failed: %d",
errno);
}
#endif
#endif // _WIN32
}
section.Leave();
arena->~Arena();
@ -545,6 +549,7 @@ static void *DoAllocWithArena(size_t request, LowLevelAlloc::Arena *arena) {
MEM_RESERVE | MEM_COMMIT, PAGE_READWRITE);
ABSL_RAW_CHECK(new_pages != nullptr, "VirtualAlloc failed");
#else
#ifndef ABSL_LOW_LEVEL_ALLOC_ASYNC_SIGNAL_SAFE_MISSING
if ((arena->flags & LowLevelAlloc::kAsyncSignalSafe) != 0) {
new_pages = base_internal::DirectMmap(nullptr, new_pages_size,
PROT_WRITE|PROT_READ, MAP_ANONYMOUS|MAP_PRIVATE, -1, 0);
@ -552,10 +557,15 @@ static void *DoAllocWithArena(size_t request, LowLevelAlloc::Arena *arena) {
new_pages = mmap(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);
#endif // ABSL_LOW_LEVEL_ALLOC_ASYNC_SIGNAL_SAFE_MISSING
if (new_pages == MAP_FAILED) {
ABSL_RAW_LOG(FATAL, "mmap error: %d", errno);
}
#endif
#endif // _WIN32
arena->mu.Lock();
s = reinterpret_cast<AllocList *>(new_pages);
s->header.size = new_pages_size;

7
absl/base/internal/low_level_alloc.h
View file

@ -39,10 +39,13 @@
#define ABSL_LOW_LEVEL_ALLOC_MISSING 1
#endif
// Using LowLevelAlloc with kAsyncSignalSafe isn't supported on Windows.
// Using LowLevelAlloc with kAsyncSignalSafe isn't supported on Windows or
// asm.js / WebAssembly.
// See https://kripken.github.io/emscripten-site/docs/porting/pthreads.html
// for more information.
#ifdef ABSL_LOW_LEVEL_ALLOC_ASYNC_SIGNAL_SAFE_MISSING
#error ABSL_LOW_LEVEL_ALLOC_ASYNC_SIGNAL_SAFE_MISSING cannot be directly set
#elif defined(_WIN32)
#elif defined(_WIN32) || defined(__asmjs__) || defined(__wasm__)
#define ABSL_LOW_LEVEL_ALLOC_ASYNC_SIGNAL_SAFE_MISSING 1
#endif

10
absl/base/internal/thread_identity.cc
View file

@ -68,6 +68,14 @@ void SetCurrentThreadIdentity(
// NOTE: Not async-safe. But can be open-coded.
absl::call_once(init_thread_identity_key_once, AllocateThreadIdentityKey,
reclaimer);
#ifdef __EMSCRIPTEN__
// Emscripten PThread implementation does not support signals.
// See https://kripken.github.io/emscripten-site/docs/porting/pthreads.html
// for more information.
pthread_setspecific(thread_identity_pthread_key,
reinterpret_cast<void*>(identity));
#else
// We must mask signals around the call to setspecific as with current glibc,
// a concurrent getspecific (needed for GetCurrentThreadIdentityIfPresent())
// may zero our value.
@ -81,6 +89,8 @@ void SetCurrentThreadIdentity(
pthread_setspecific(thread_identity_pthread_key,
reinterpret_cast<void*>(identity));
pthread_sigmask(SIG_SETMASK, &curr_signals, nullptr);
#endif // !__EMSCRIPTEN__
#elif ABSL_THREAD_IDENTITY_MODE == ABSL_THREAD_IDENTITY_MODE_USE_TLS
// NOTE: Not async-safe. But can be open-coded.
absl::call_once(init_thread_identity_key_once, AllocateThreadIdentityKey,