From 078b89b3c046d230ef3ad39494e5852184eb528b Mon Sep 17 00:00:00 2001 From: Abseil Team Date: Wed, 23 Oct 2019 19:35:39 -0700 Subject: Export of internal Abseil changes -- e54b9c7bbb0c58475676c268e2e19c69f4bce48a by Jorg Brown : Tweak ABSL_PREDICT_TRUE slightly, for better code on some platforms and/or optimization levels. "false || (x)" is more verbose than "!!(x)", but ultimately more efficient. For example, given this code: void InitIfNecessary() { if (ABSL_PREDICT_TRUE(NeedsInit())) { SlowInitIfNecessary(); } } Clang with default optimization level will produce: Before this CL After this CL InitIfNecessary: InitIfNecessary: push rbp push rbp mov rbp, rsp mov rbp, rsp call NeedsInit call NeedsInit xor al, -1 xor al, -1 test al, 1 test al, 1 jne .LBB2_1 jne .LBB3_1 jmp .LBB2_2 jmp .LBB3_2 .LBB2_1: .LBB3_1: call SlowInitIfNecessary call SlowInitIfNecessary .LBB2_2: .LBB3_2: pop rbp pop rbp ret ret PiperOrigin-RevId: 276401386 -- 0a3c4dfd8342bf2b1b11a87f1c662c883f73cab7 by Abseil Team : Fix comment nit: sem_open => sem_init. The code calls sem_init, not sem_open, to initialize an unnamed semaphore. (sem_open creates or opens a named semaphore.) PiperOrigin-RevId: 276344072 -- b36a664e9459057509a90e83d3482e1d3a4c44c7 by Abseil Team : Fix typo in flat_hash_map.h: exchaged -> exchanged PiperOrigin-RevId: 276295792 -- 7bbd8d18276eb110c8335743e35fceb662ddf3d6 by Samuel Benzaquen : Add assertions to verify use of iterators. PiperOrigin-RevId: 276283300 -- 677398a8ffcb1f59182cffe57a4fe7ff147a0404 by Laramie Leavitt : Migrate distribution_impl.h/cc to generate_real.h/cc. Combine the methods RandU64To into a single method: GenerateRealFromBits(). Remove rejection sampling from absl::uniform_real_distribution. PiperOrigin-RevId: 276158675 -- c60c9d11d24b0c546329d998e78e15a84b3153f5 by Abseil Team : Internal change PiperOrigin-RevId: 276126962 -- 4c840cab6a8d86efa29b397cafaf7520eece68cc by Andy Soffer : Update CMakeLists.txt to address https://github.com/abseil/abseil-cpp/issues/365. This does not cover every platform, but it does at least address the first-order issue of assuming gcc implies x86. PiperOrigin-RevId: 276116253 -- 98da366e6b5d51afe5d7ac6722126aca23d85ee6 by Abseil Team : Internal change PiperOrigin-RevId: 276097452 GitOrigin-RevId: e54b9c7bbb0c58475676c268e2e19c69f4bce48a Change-Id: I02d84454bb71ab21ad3d39650acf6cc6e36f58d7 --- absl/container/internal/raw_hash_set.h | 20 +++++++++++++++++--- 1 file changed, 17 insertions(+), 3 deletions(-) (limited to 'absl/container/internal/raw_hash_set.h') diff --git a/absl/container/internal/raw_hash_set.h b/absl/container/internal/raw_hash_set.h index 42b3c46..9992ba4 100644 --- a/absl/container/internal/raw_hash_set.h +++ b/absl/container/internal/raw_hash_set.h @@ -614,13 +614,17 @@ class raw_hash_set { iterator() {} // PRECONDITION: not an end() iterator. - reference operator*() const { return PolicyTraits::element(slot_); } + reference operator*() const { + /* To be enabled: assert_is_full(); */ + return PolicyTraits::element(slot_); + } // PRECONDITION: not an end() iterator. pointer operator->() const { return &operator*(); } // PRECONDITION: not an end() iterator. iterator& operator++() { + /* To be enabled: assert_is_full(); */ ++ctrl_; ++slot_; skip_empty_or_deleted(); @@ -634,6 +638,8 @@ class raw_hash_set { } friend bool operator==(const iterator& a, const iterator& b) { + /* To be enabled: a.assert_is_valid(); */ + /* To be enabled: b.assert_is_valid(); */ return a.ctrl_ == b.ctrl_; } friend bool operator!=(const iterator& a, const iterator& b) { @@ -644,6 +650,11 @@ class raw_hash_set { iterator(ctrl_t* ctrl) : ctrl_(ctrl) {} // for end() iterator(ctrl_t* ctrl, slot_type* slot) : ctrl_(ctrl), slot_(slot) {} + void assert_is_full() const { assert(IsFull(*ctrl_)); } + void assert_is_valid() const { + assert(!ctrl_ || IsFull(*ctrl_) || *ctrl_ == kSentinel); + } + void skip_empty_or_deleted() { while (IsEmptyOrDeleted(*ctrl_)) { // ctrl is not necessarily aligned to Group::kWidth. It is also likely @@ -1155,7 +1166,7 @@ class raw_hash_set { // This overload is necessary because otherwise erase(const K&) would be // a better match if non-const iterator is passed as an argument. void erase(iterator it) { - assert(it != end()); + it.assert_is_full(); PolicyTraits::destroy(&alloc_ref(), it.slot_); erase_meta_only(it); } @@ -1172,12 +1183,14 @@ class raw_hash_set { template void merge(raw_hash_set& src) { // NOLINT assert(this != &src); - for (auto it = src.begin(), e = src.end(); it != e; ++it) { + for (auto it = src.begin(), e = src.end(); it != e;) { + auto next = std::next(it); if (PolicyTraits::apply(InsertSlot{*this, std::move(*it.slot_)}, PolicyTraits::element(it.slot_)) .second) { src.erase_meta_only(it); } + it = next; } } @@ -1187,6 +1200,7 @@ class raw_hash_set { } node_type extract(const_iterator position) { + position.inner_.assert_is_full(); auto node = CommonAccess::Transfer(alloc_ref(), position.inner_.slot_); erase_meta_only(position); -- cgit v1.2.3