has basic_string call basic_string_view's assume-valid constructor
#105863
+10
−6
Conversation
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
`basic_string` frequently calls `basic_string_view(data(), size())`, which accounts for ~15% of the observed overhead when hardening is enabled. This commit removes unnecessary checks when `basic_string` is known to already have valid data, by bypassing the public constructor, so that we eliminate that overhead.
llvmbot
added
the
libc++
|
@llvm/pr-subscribers-libcxx Author: Christopher Di Bella (cjdb) Changes
This was originally #105441, but I somehow messed up and rebased an older version of LLVM onto ToT. Full diff: https://github.com/llvm/llvm-project/pull/105863.diff 2 Files Affected:
diff --git a/libcxx/include/string b/libcxx/include/string
index 6e93a6230cc2c0..cdc1afedbdf52f 100644
--- a/libcxx/include/string
+++ b/libcxx/include/string
@@ -1213,7 +1213,7 @@ public:
}
_LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 operator __self_view() const _NOEXCEPT {
- return __self_view(data(), size());
+ return __self_view(typename __self_view::__assume_valid(), data(), size());
}
_LIBCPP_CONSTEXPR_SINCE_CXX20 _LIBCPP_STRING_INTERNAL_MEMORY_ACCESS basic_string&
@@ -1822,7 +1822,7 @@ public:
#if _LIBCPP_STD_VER >= 20
constexpr _LIBCPP_HIDE_FROM_ABI bool starts_with(__self_view __sv) const noexcept {
- return __self_view(data(), size()).starts_with(__sv);
+ return __self_view(typename __self_view::__assume_valid(), data(), size()).starts_with(__sv);
}
constexpr _LIBCPP_HIDE_FROM_ABI bool starts_with(value_type __c) const noexcept {
@@ -1834,7 +1834,7 @@ public:
}
constexpr _LIBCPP_HIDE_FROM_ABI bool ends_with(__self_view __sv) const noexcept {
- return __self_view(data(), size()).ends_with(__sv);
+ return __self_view(typename __self_view::__assume_valid(), data(), size()).ends_with(__sv);
}
constexpr _LIBCPP_HIDE_FROM_ABI bool ends_with(value_type __c) const noexcept {
@@ -1848,15 +1848,15 @@ public:
#if _LIBCPP_STD_VER >= 23
constexpr _LIBCPP_HIDE_FROM_ABI bool contains(__self_view __sv) const noexcept {
- return __self_view(data(), size()).contains(__sv);
+ return __self_view(typename __self_view::__assume_valid(), data(), size()).contains(__sv);
}
constexpr _LIBCPP_HIDE_FROM_ABI bool contains(value_type __c) const noexcept {
- return __self_view(data(), size()).contains(__c);
+ return __self_view(typename __self_view::__assume_valid(), data(), size()).contains(__c);
}
constexpr _LIBCPP_HIDE_FROM_ABI bool contains(const value_type* __s) const {
- return __self_view(data(), size()).contains(__s);
+ return __self_view(typename __self_view::__assume_valid(), data(), size()).contains(__s);
}
#endif
diff --git a/libcxx/include/string_view b/libcxx/include/string_view
index 2a03ee99e9ab52..c81dbc9873b128 100644
--- a/libcxx/include/string_view
+++ b/libcxx/include/string_view
@@ -212,6 +212,7 @@ namespace std {
#include <__functional/unary_function.h>
#include <__fwd/ostream.h>
#include <__fwd/string_view.h>
+#include <__fwd/string.h>
#include <__iterator/bounded_iter.h>
#include <__iterator/concepts.h>
#include <__iterator/iterator_traits.h>
@@ -689,6 +690,9 @@ private:
const value_type* __data_;
size_type __size_;
+
+ template <class, class, class>
+ friend class basic_string;
};
_LIBCPP_CTAD_SUPPORTED_FOR_TYPE(basic_string_view);
|
|
✅ With the latest revision this PR passed the C/C++ code formatter. |
5c4lar
pushed a commit
to 5c4lar/llvm-project
that referenced
this pull request
Aug 29, 2024
…_string operations (llvm#105863) `basic_string` frequently calls `basic_string_view(data(), size())`, which accounts for ~15% of the observed overhead when hardening is enabled. This commit removes unnecessary checks when `basic_string` is known to already have valid data, by bypassing the public constructor, so that we eliminate that overhead.
dmpolukhin
pushed a commit
to dmpolukhin/llvm-project
that referenced
this pull request
Sep 2, 2024
…_string operations (llvm#105863) `basic_string` frequently calls `basic_string_view(data(), size())`, which accounts for ~15% of the observed overhead when hardening is enabled. This commit removes unnecessary checks when `basic_string` is known to already have valid data, by bypassing the public constructor, so that we eliminate that overhead.
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
Add this suggestion to a batch that can be applied as a single commit.
This suggestion is invalid because no changes were made to the code.
Suggestions cannot be applied while the pull request is closed.
Suggestions cannot be applied while viewing a subset of changes.
Only one suggestion per line can be applied in a batch.
Add this suggestion to a batch that can be applied as a single commit.
Applying suggestions on deleted lines is not supported.
You must change the existing code in this line in order to create a valid suggestion.
Outdated suggestions cannot be applied.
This suggestion has been applied or marked resolved.
Suggestions cannot be applied from pending reviews.
Suggestions cannot be applied on multi-line comments.
Suggestions cannot be applied while the pull request is queued to merge.
Suggestion cannot be applied right now. Please check back later.
basic_stringfrequently callsbasic_string_view(data(), size()), which accounts for ~15% of the observed overhead when hardening is enabled. This commit removes unnecessary checks whenbasic_stringis known to already have valid data, by bypassing the public constructor, so that we eliminate that overhead.This was originally #105441, but I somehow messed up and rebased an older version of LLVM onto ToT.