maurice/snix
1
0
Fork 0
Code Issues Pull requests Projects Releases Packages Wiki Activity Actions

Export of internal Abseil changes

Browse source 
--
1bc4d36e13fb9175ea8cdaa00213aa9d4417c669 by Andy Getzendanner <durandal@google.com>:

Fix pointer format specifier in documentation

Import of https://github.com/abseil/abseil-cpp/pull/614

PiperOrigin-RevId: 293227540

--
c7b43b30493c4fb5f2ec3264672b08bfe1ea3709 by Abseil Team <absl-team@google.com>:

Internal change.

PiperOrigin-RevId: 293160245

--
64439365e2b4a0b5e51ae0a7dafdb15912402dfd by Shahriar Rouf <nafi@google.com>:

Add benchmarks for string_view: BM_CompareFirstOneLess and BM_CompareSecondOneLess.

PiperOrigin-RevId: 293031676

--
b273b420cab24a6e3f487430987e09f4eb1caec4 by Greg Falcon <gfalcon@google.com>:

Remove an unreachable line from charconv.cc.

Fixes github issue #613.

PiperOrigin-RevId: 292980167

--
70babb5f7a3d9fdd00a2b3085c3c2b9fe0265c79 by Gennadiy Rozental <rogeeff@google.com>:

Move GetFlag implementation into FlagImpl.

This change will allow us to hide details of GetFlag overloads inside implementation detais. Eventually we'll migrate to a different implementation. No semantic changes in this CL.

PiperOrigin-RevId: 292930847

--
94bee7b7cc31e0167ee4b953281c1e78c96a574a by Abseil Team <absl-team@google.com>:

Clarification in absl::Exponential documentation.

PiperOrigin-RevId: 292912672

--
d6916d30c5c1d3ee9ae46d69ec0a166a760c99c7 by Derek Mauro <dmauro@google.com>:

Make AtomicHook constant-initializable on Clang for Windows.

Only mark AtomicHook as constant-initializable on platforms where it
is actually constant-initializable.

PiperOrigin-RevId: 292655939
GitOrigin-RevId: 1bc4d36e13fb9175ea8cdaa00213aa9d4417c669
Change-Id: I090b231a0ca0d92868e494ab5b3fa86c902889d5
This commit is contained in:
Abseil Team 2020-02-04 14:18:00 -08:00 • committed by Andy Getz
parent 36bcd9599b
commit 08a7e7bf97
15 changed files with 315 additions and 228 deletions
Download patch file Download diff file Expand all files Collapse all files

39
absl/base/internal/atomic_hook.h
View file

@ -20,16 +20,21 @@
#include <cstdint>
#include <utility>
#include "absl/base/attributes.h"
#include "absl/base/config.h"
#ifdef _MSC_FULL_VER
#define ABSL_HAVE_WORKING_ATOMIC_POINTER 0
#if defined(_MSC_VER) && !defined(__clang__)
#define ABSL_HAVE_WORKING_CONSTEXPR_STATIC_INIT 0
#else
#define ABSL_HAVE_WORKING_ATOMIC_POINTER 1
#define ABSL_HAVE_WORKING_CONSTEXPR_STATIC_INIT 1
#endif
#if defined(_MSC_VER)
#define ABSL_HAVE_WORKING_ATOMIC_POINTER 0
#else
#define ABSL_HAVE_WORKING_ATOMIC_POINTER 1
#endif
namespace absl {
ABSL_NAMESPACE_BEGIN
namespace base_internal {
@ -37,6 +42,15 @@ namespace base_internal {
template <typename T>
class AtomicHook;
// To workaround AtomicHook not being constant-initializable on some platforms,
// prefer to annotate instances with `ABSL_INTERNAL_ATOMIC_HOOK_ATTRIBUTES`
// instead of `ABSL_CONST_INIT`.
#if ABSL_HAVE_WORKING_CONSTEXPR_STATIC_INIT
#define ABSL_INTERNAL_ATOMIC_HOOK_ATTRIBUTES ABSL_CONST_INIT
#else
#define ABSL_INTERNAL_ATOMIC_HOOK_ATTRIBUTES
#endif
// `AtomicHook` is a helper class, templatized on a raw function pointer type,
// for implementing Abseil customization hooks. It is a callable object that
// dispatches to the registered hook. Objects of type `AtomicHook` must have
@ -45,8 +59,11 @@ class AtomicHook;
// A default constructed object performs a no-op (and returns a default
// constructed object) if no hook has been registered.
//
// Hooks can be pre-registered via constant initialization, for example,
// `ABSL_CONST_INIT static AtomicHook<void(*)()> my_hook(DefaultAction);`
// Hooks can be pre-registered via constant initialization, for example:
//
// ABSL_INTERNAL_ATOMIC_HOOK_ATTRIBUTES static AtomicHook<void(*)()>
// my_hook(DefaultAction);
//
// and then changed at runtime via a call to `Store()`.
//
// Reads and writes guarantee memory_order_acquire/memory_order_release
@ -65,11 +82,15 @@ class AtomicHook<ReturnType (*)(Args...)> {
#if ABSL_HAVE_WORKING_ATOMIC_POINTER && ABSL_HAVE_WORKING_CONSTEXPR_STATIC_INIT
explicit constexpr AtomicHook(FnPtr default_fn)
: hook_(default_fn), default_fn_(default_fn) {}
#elif ABSL_HAVE_WORKING_CONSTEXPR_STATIC_INIT
explicit constexpr AtomicHook(FnPtr default_fn)
: hook_(kUninitialized), default_fn_(default_fn) {}
#else
// On MSVC, this function sometimes executes after dynamic initialization =(.
// If a non-zero `hook_` has been installed by a dynamic initializer, we want
// to preserve it. If not, `hook_` will be zero initialized and we have no
// need to set it to `kUninitialized`.
// As of January 2020, on all known versions of MSVC this constructor runs in
// the global constructor sequence. If `Store()` is called by a dynamic
// initializer, we want to preserve the value, even if this constructor runs
// after the call to `Store()`. If not, `hook_` will be
// zero-initialized by the linker and we have no need to set it.
// https://developercommunity.visualstudio.com/content/problem/336946/class-with-constexpr-constructor-not-using-static.html
explicit constexpr AtomicHook(FnPtr default_fn)
: /* hook_(deliberately omitted), */ default_fn_(default_fn) {