[libcxx-commits] [libcxx] [libc++] Refactor vector's ASan annotations to only ever delete and add the annotations (PR #152967)
Nikolas Klauser via libcxx-commits
libcxx-commits at lists.llvm.org
Mon Aug 11 01:06:08 PDT 2025
https://github.com/philnik777 created https://github.com/llvm/llvm-project/pull/152967
This significantly simplifies the places where we insert/delete elements, since the code is exactly what you'd naively implement now. This also probably fixes some annotation issues when exceptions are thrown, since that will be handled correctly now through `__scope_guard`.
>From 9277fc1fd0f0a874673d5d144b6436828e91ac1e Mon Sep 17 00:00:00 2001
From: Nikolas Klauser <nikolasklauser at berlin.de>
Date: Mon, 11 Aug 2025 10:02:01 +0200
Subject: [PATCH] [libc++] Refactor vector's ASan annotations to only ever
delete and add the annotations
---
libcxx/include/__vector/vector.h | 87 +++++++++++++-------------------
1 file changed, 36 insertions(+), 51 deletions(-)
diff --git a/libcxx/include/__vector/vector.h b/libcxx/include/__vector/vector.h
index 4307e78f6ddbc..b9b8c654bc8b4 100644
--- a/libcxx/include/__vector/vector.h
+++ b/libcxx/include/__vector/vector.h
@@ -65,6 +65,7 @@
#include <__utility/is_pointer_in_range.h>
#include <__utility/move.h>
#include <__utility/pair.h>
+#include <__utility/scope_guard.h>
#include <__utility/swap.h>
#include <initializer_list>
#include <limits>
@@ -479,9 +480,10 @@ class vector {
_LIBCPP_CONSTEXPR_SINCE_CXX20 _LIBCPP_HIDE_FROM_ABI void __emplace_back_assume_capacity(_Args&&... __args) {
_LIBCPP_ASSERT_INTERNAL(
size() < capacity(), "We assume that we have enough space to insert an element at the end of the vector");
- _ConstructTransaction __tx(*this, 1);
- __alloc_traits::construct(this->__alloc_, std::__to_address(__tx.__pos_), std::forward<_Args>(__args)...);
- ++__tx.__pos_;
+ __annotate_delete();
+ auto __guard = std::__make_scope_guard(__annotate_new_size(*this));
+ __alloc_traits::construct(this->__alloc_, std::__to_address(__end_), std::forward<_Args>(__args)...);
+ ++__end_;
}
#if _LIBCPP_STD_VER >= 23
@@ -548,9 +550,9 @@ class vector {
_LIBCPP_CONSTEXPR_SINCE_CXX20 _LIBCPP_HIDE_FROM_ABI iterator erase(const_iterator __first, const_iterator __last);
_LIBCPP_CONSTEXPR_SINCE_CXX20 _LIBCPP_HIDE_FROM_ABI void clear() _NOEXCEPT {
- size_type __old_size = size();
+ __annotate_delete();
+ auto __guard = std::__make_scope_guard(__annotate_new_size(*this));
__base_destruct_at_end(this->__begin_);
- __annotate_shrink(__old_size);
}
_LIBCPP_CONSTEXPR_SINCE_CXX20 _LIBCPP_HIDE_FROM_ABI void resize(size_type __sz);
@@ -708,9 +710,9 @@ class vector {
_LIBCPP_CONSTEXPR_SINCE_CXX20 _LIBCPP_HIDE_FROM_ABI void __move_assign(vector& __c, false_type)
_NOEXCEPT_(__alloc_traits::is_always_equal::value);
_LIBCPP_CONSTEXPR_SINCE_CXX20 _LIBCPP_HIDE_FROM_ABI void __destruct_at_end(pointer __new_last) _NOEXCEPT {
- size_type __old_size = size();
+ __annotate_delete();
+ auto __guard = std::__make_scope_guard(__annotate_new_size(*this));
__base_destruct_at_end(__new_last);
- __annotate_shrink(__old_size);
}
template <class... _Args>
@@ -737,33 +739,11 @@ class vector {
__annotate_contiguous_container(data() + size(), data() + capacity());
}
- _LIBCPP_CONSTEXPR_SINCE_CXX20 _LIBCPP_HIDE_FROM_ABI void __annotate_increase(size_type __n) const _NOEXCEPT {
- __annotate_contiguous_container(data() + size(), data() + size() + __n);
- }
-
- _LIBCPP_CONSTEXPR_SINCE_CXX20 _LIBCPP_HIDE_FROM_ABI void __annotate_shrink(size_type __old_size) const _NOEXCEPT {
- __annotate_contiguous_container(data() + __old_size, data() + size());
- }
-
- struct _ConstructTransaction {
- _LIBCPP_CONSTEXPR_SINCE_CXX20 _LIBCPP_HIDE_FROM_ABI explicit _ConstructTransaction(vector& __v, size_type __n)
- : __v_(__v), __pos_(__v.__end_), __new_end_(__v.__end_ + __n) {
- __v_.__annotate_increase(__n);
- }
-
- _LIBCPP_CONSTEXPR_SINCE_CXX20 _LIBCPP_HIDE_FROM_ABI ~_ConstructTransaction() {
- __v_.__end_ = __pos_;
- if (__pos_ != __new_end_) {
- __v_.__annotate_shrink(__new_end_ - __v_.__begin_);
- }
- }
-
- vector& __v_;
- pointer __pos_;
- const_pointer const __new_end_;
+ struct __annotate_new_size {
+ vector& __vec_;
- _ConstructTransaction(_ConstructTransaction const&) = delete;
- _ConstructTransaction& operator=(_ConstructTransaction const&) = delete;
+ _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 __annotate_new_size(vector& __vec) : __vec_(__vec) {}
+ _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 void operator()() { __vec_.__annotate_new(__vec_.size()); }
};
_LIBCPP_CONSTEXPR_SINCE_CXX20 _LIBCPP_HIDE_FROM_ABI void __base_destruct_at_end(pointer __new_last) _NOEXCEPT {
@@ -850,6 +830,7 @@ template <class _Tp, class _Allocator>
_LIBCPP_CONSTEXPR_SINCE_CXX20 void
vector<_Tp, _Allocator>::__swap_out_circular_buffer(__split_buffer<value_type, allocator_type&>& __v) {
__annotate_delete();
+ auto __guard = std::__make_scope_guard(__annotate_new_size(*this));
auto __new_begin = __v.__begin_ - (__end_ - __begin_);
std::__uninitialized_allocator_relocate(
this->__alloc_, std::__to_address(__begin_), std::__to_address(__end_), std::__to_address(__new_begin));
@@ -859,7 +840,6 @@ vector<_Tp, _Allocator>::__swap_out_circular_buffer(__split_buffer<value_type, a
std::swap(this->__end_, __v.__end_);
std::swap(this->__cap_, __v.__cap_);
__v.__first_ = __v.__begin_;
- __annotate_new(size());
}
// __swap_out_circular_buffer relocates the objects in [__begin_, __p) into the front of __v, the objects in
@@ -870,6 +850,7 @@ template <class _Tp, class _Allocator>
_LIBCPP_CONSTEXPR_SINCE_CXX20 typename vector<_Tp, _Allocator>::pointer
vector<_Tp, _Allocator>::__swap_out_circular_buffer(__split_buffer<value_type, allocator_type&>& __v, pointer __p) {
__annotate_delete();
+ auto __guard = std::__make_scope_guard(__annotate_new_size(size()));
pointer __ret = __v.__begin_;
// Relocate [__p, __end_) first to avoid having a hole in [__begin_, __end_)
@@ -889,7 +870,6 @@ vector<_Tp, _Allocator>::__swap_out_circular_buffer(__split_buffer<value_type, a
std::swap(this->__end_, __v.__end_);
std::swap(this->__cap_, __v.__cap_);
__v.__first_ = __v.__begin_;
- __annotate_new(size());
return __ret;
}
@@ -923,10 +903,12 @@ vector<_Tp, _Allocator>::__recommend(size_type __new_size) const {
// Postcondition: size() == size() + __n
template <class _Tp, class _Allocator>
_LIBCPP_CONSTEXPR_SINCE_CXX20 void vector<_Tp, _Allocator>::__construct_at_end(size_type __n) {
- _ConstructTransaction __tx(*this, __n);
- const_pointer __new_end = __tx.__new_end_;
- for (pointer __pos = __tx.__pos_; __pos != __new_end; __tx.__pos_ = ++__pos) {
- __alloc_traits::construct(this->__alloc_, std::__to_address(__pos));
+ __annotate_delete();
+ auto __guard = std::__make_scope_guard(__annotate_new_size(*this));
+
+ for (size_t __i = 0; __i != __n; ++__i) {
+ __alloc_traits::construct(this->__alloc_, std::__to_address(__end_));
+ ++__end_;
}
}
@@ -939,10 +921,12 @@ _LIBCPP_CONSTEXPR_SINCE_CXX20 void vector<_Tp, _Allocator>::__construct_at_end(s
template <class _Tp, class _Allocator>
_LIBCPP_CONSTEXPR_SINCE_CXX20 inline void
vector<_Tp, _Allocator>::__construct_at_end(size_type __n, const_reference __x) {
- _ConstructTransaction __tx(*this, __n);
- const_pointer __new_end = __tx.__new_end_;
- for (pointer __pos = __tx.__pos_; __pos != __new_end; __tx.__pos_ = ++__pos) {
- __alloc_traits::construct(this->__alloc_, std::__to_address(__pos), __x);
+ __annotate_delete();
+ auto __guard = std::__make_scope_guard(__annotate_new_size(*this));
+
+ for (size_t __i = 0; __i != __n; ++__i) {
+ __alloc_traits::construct(this->__alloc_, std::__to_address(__end_), __x);
+ ++__end_;
}
}
@@ -950,8 +934,8 @@ template <class _Tp, class _Allocator>
template <class _InputIterator, class _Sentinel>
_LIBCPP_CONSTEXPR_SINCE_CXX20 void
vector<_Tp, _Allocator>::__construct_at_end(_InputIterator __first, _Sentinel __last, size_type __n) {
- _ConstructTransaction __tx(*this, __n);
- __tx.__pos_ = std::__uninitialized_allocator_copy(this->__alloc_, std::move(__first), std::move(__last), __tx.__pos_);
+ auto __guard = std::__make_scope_guard(__annotate_new_size(*this));
+ __end_ = std::__uninitialized_allocator_copy(this->__alloc_, std::move(__first), std::move(__last), __end_);
}
// Default constructs __n objects starting at __end_
@@ -1189,15 +1173,16 @@ vector<_Tp, _Allocator>::erase(const_iterator __first, const_iterator __last) {
template <class _Tp, class _Allocator>
_LIBCPP_CONSTEXPR_SINCE_CXX20 void
vector<_Tp, _Allocator>::__move_range(pointer __from_s, pointer __from_e, pointer __to) {
+ __annotate_delete();
+ auto __guard = std::__make_scope_guard(__annotate_new_size(*this));
pointer __old_last = this->__end_;
difference_type __n = __old_last - __to;
- {
- pointer __i = __from_s + __n;
- _ConstructTransaction __tx(*this, __from_e - __i);
- for (pointer __pos = __tx.__pos_; __i < __from_e; ++__i, (void)++__pos, __tx.__pos_ = __pos) {
- __alloc_traits::construct(this->__alloc_, std::__to_address(__pos), std::move(*__i));
- }
+
+ for (pointer __i = __from_s + __n; __i != __from_e; ++__i) {
+ __alloc_traits::construct(this->__alloc_, std::__to_address(__end_), std::move(*__i));
+ ++__end_;
}
+
std::move_backward(__from_s, __from_s + __n, __old_last);
}
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