mirrors/llvm-project
0
0
Fork 0
mirror of https://github.com/llvm/llvm-project.git synced 2025-04-25 19:26:06 +00:00
Code Issues Projects Releases Wiki Activity
llvm-project/libcxx/include
History
Martijn Vels 2bad222680 Add optimization to basic_string::assign for compile-time known constant values. 
Summary:
This change optimizes the assign() methods for string where either the contents or lengths are compile time known constants. For small strings (< min_cap) we can execute the assignment entirely inline. For strings up to 128 bytes we allow the compiler to efficiently inline the copy operation after we call the offline __resize<>() method. Short / long branches are taken at the call site for better branch prediction and allowing FDO optimizations.

Benchmarks (unstable / google perflab):
```
name                                                old time/op             new time/op             delta
BM_StringAssignAsciiz_Empty_Opaque                  5.69ns ± 7%             5.97ns ± 7%     ~             (p=0.056 n=5+5)
BM_StringAssignAsciiz_Empty_Transparent             5.39ns ± 7%             0.79ns ± 8%  -85.36%          (p=0.008 n=5+5)
BM_StringAssignAsciiz_Small_Opaque                  11.2ns ± 5%             11.0ns ± 6%     ~             (p=0.548 n=5+5)
BM_StringAssignAsciiz_Small_Transparent             10.1ns ± 7%              1.0ns ± 8%  -89.76%          (p=0.008 n=5+5)
BM_StringAssignAsciiz_Large_Opaque                  23.5ns ± 7%             23.8ns ± 7%     ~             (p=0.841 n=5+5)
BM_StringAssignAsciiz_Large_Transparent             21.4ns ± 7%             12.7ns ± 7%  -40.83%          (p=0.008 n=5+5)
BM_StringAssignAsciiz_Huge_Opaque                    336ns ± 4%              327ns ± 7%     ~             (p=0.421 n=5+5)
BM_StringAssignAsciiz_Huge_Transparent               331ns ± 5%              324ns ± 7%     ~             (p=0.548 n=5+5)
BM_StringAssignAsciizMix_Opaque                     13.6ns ±10%             13.7ns ± 9%     ~             (p=0.690 n=5+5)
BM_StringAssignAsciizMix_Transparent                12.9ns ± 8%              3.6ns ± 8%  -71.82%          (p=0.008 n=5+5)
```

Reviewers: EricWF, #libc!

Subscribers: jfb, libcxx-commits

Tags: #libc

Differential Revision: https://reviews.llvm.org/D82221
2020-06-29 14:34:34 -04:00
..
experimental
[NFC] Strip trailing whitespace from libc++
2019-10-23 11:19:19 -07:00
ext
[libc++] Cleanup and enable multiple warnings.
2019-12-12 21:09:08 -05:00
support
[libcxx] [Windows] Store the lconv struct returned from localeconv in locale_t
2020-01-29 22:37:11 +02:00
__bit_reference
[libc++] Fix ABI break in __bit_reference.
2020-02-19 12:02:06 -05:00
__bsd_locale_defaults.h
Update more file headers across all of the LLVM projects in the monorepo
2019-01-19 10:56:40 +00:00
__bsd_locale_fallbacks.h
Update more file headers across all of the LLVM projects in the monorepo
2019-01-19 10:56:40 +00:00
__config
[libc++] Remove deprecated _LIBCPP_ALTERNATE_STRING_LAYOUT macro
2020-06-25 16:33:30 -04:00
__config_site.in
[libc++] Fix the LIBCXX_HAS_MERGED_TYPEINFO_NAMES_DEFAULT setting
2020-05-29 06:14:30 -04:00
__debug
[libc++][NFC] Remove excess trailing newlines from most files
2019-10-23 08:08:57 -07:00
__errc
Update more file headers across all of the LLVM projects in the monorepo
2019-01-19 10:56:40 +00:00
__functional_03
[libc++] Properly mark std::function as deprecated in C++03
2020-03-10 17:45:39 -04:00
__functional_base
[libc++] Fix unintended ADL inside ref(reference_wrapper<T>) and cref(reference_wrapper<T>)
2020-02-20 12:22:21 -05:00
__functional_base_03
Update more file headers across all of the LLVM projects in the monorepo
2019-01-19 10:56:40 +00:00
__hash_table
[libc++] Rework compressed pair constructors.
2019-12-16 18:38:58 -05:00
__libcpp_version
Bump the trunk major version to 11
2020-01-15 13:38:01 +01:00
__locale
Upstream Bionic definitions of ctype_base/regex.
2020-04-06 13:38:16 -07:00
__mutex_base
[libc++] Ensure __config always defines certain configuration macros.
2019-12-13 15:42:07 -05:00
__node_handle
Avoid name conflict with kernel headers
2019-04-24 09:43:44 +00:00
__nullptr
Update more file headers across all of the LLVM projects in the monorepo
2019-01-19 10:56:40 +00:00
__split_buffer
[libc++] Rework compressed pair constructors.
2019-12-16 18:38:58 -05:00
__sso_allocator
Update more file headers across all of the LLVM projects in the monorepo
2019-01-19 10:56:40 +00:00
__std_stream
Update more file headers across all of the LLVM projects in the monorepo
2019-01-19 10:56:40 +00:00
__string
Add optimization to basic_string::assign for compile-time known constant values.
2020-06-29 14:34:34 -04:00
__threading_support
Fix compile for -DLIBCXX_BUILD_EXTERNAL_THREAD_LIBRARY
2020-05-21 13:48:59 +01:00
__tree
[libc++] Rework compressed pair constructors.
2019-12-16 18:38:58 -05:00
__tuple
Refactor default constructor SFINAE in pair and tuple.
2019-09-30 20:55:30 +00:00
__undef_macros
Update the file headers across all of the LLVM projects in the monorepo
2019-01-19 08:50:56 +00:00
algorithm
Rename __is_foo_iterator traits to reflect their Cpp17 nature.
2019-11-18 01:49:32 -05:00
any
[NFC][libc++] Remove stray semi-colon after function definition
2019-06-19 16:33:28 +00:00
array
[libc++] Add assertions on OOB accesses in std::array when the debug mode is enabled
2020-06-01 16:37:39 -04:00
atomic
Updated synopsis of <atomic> to match what is implemented
2020-06-01 14:30:13 -07:00
barrier
[libc++] Add availability markup for the C++20 Synchronization Library on Apple
2020-04-06 18:07:26 -04:00
bit
[libc++] NFC: Remove outdated numbering in <bit> synopsis
2020-05-28 14:31:21 -04:00
bitset
Ensure bitset's string constructor doesn't poison the overload set.
2019-07-01 19:59:34 +00:00
cassert
Update more file headers across all of the LLVM projects in the monorepo
2019-01-19 10:56:40 +00:00
ccomplex
Update more file headers across all of the LLVM projects in the monorepo
2019-01-19 10:56:40 +00:00
cctype
Update more file headers across all of the LLVM projects in the monorepo
2019-01-19 10:56:40 +00:00
cerrno
Update more file headers across all of the LLVM projects in the monorepo
2019-01-19 10:56:40 +00:00
cfenv
Update more file headers across all of the LLVM projects in the monorepo
2019-01-19 10:56:40 +00:00
cfloat
Update more file headers across all of the LLVM projects in the monorepo
2019-01-19 10:56:40 +00:00
charconv
[libc++] Mark __u64toa and __u32toa as noexcept
2020-05-22 16:11:44 -04:00
chrono
[libc++] Avoid UB in year_month_day_last::day() for incorrect months
2020-06-09 13:43:13 -04:00
cinttypes
Update the file headers across all of the LLVM projects in the monorepo
2019-01-19 08:50:56 +00:00
ciso646
Update more file headers across all of the LLVM projects in the monorepo
2019-01-19 10:56:40 +00:00
climits
Update more file headers across all of the LLVM projects in the monorepo
2019-01-19 10:56:40 +00:00
clocale
Update more file headers across all of the LLVM projects in the monorepo
2019-01-19 10:56:40 +00:00
CMakeLists.txt
[libc++] Remove support for building through llvm-config
2020-06-26 15:13:04 -04:00
cmath
[libc++] [LWG3201] Update status page: lerp should be marked noexcept.
2020-05-25 22:28:21 +02:00
codecvt
Fix -Wdeprecated-copy-dtor and -Wdeprecated-dynamic-exception-spec warnings.
2020-03-17 18:59:54 +01:00
compare
[libc++] Add equality for spaceship types for themselves
2020-06-18 10:22:50 -04:00
complex
[libc++] Fix ostream for complex numbers with fixed field width
2020-05-07 13:51:07 -04:00
complex.h
Update more file headers across all of the LLVM projects in the monorepo
2019-01-19 10:56:40 +00:00
concepts
[libcxx] Adds [concept.same]
2020-04-08 18:00:13 -04:00
condition_variable
Update more file headers across all of the LLVM projects in the monorepo
2019-01-19 10:56:40 +00:00
csetjmp
Update more file headers across all of the LLVM projects in the monorepo
2019-01-19 10:56:40 +00:00
csignal
Update more file headers across all of the LLVM projects in the monorepo
2019-01-19 10:56:40 +00:00
cstdarg
Update more file headers across all of the LLVM projects in the monorepo
2019-01-19 10:56:40 +00:00
cstdbool
Update more file headers across all of the LLVM projects in the monorepo
2019-01-19 10:56:40 +00:00
cstddef
Avoid using std::max_align_t in pre-C++11 mode
2020-04-04 01:38:41 +02:00
cstdint
Update more file headers across all of the LLVM projects in the monorepo
2019-01-19 10:56:40 +00:00
cstdio
Reland: Don't expose unavailable cstdio functions.
2020-04-16 12:51:08 -07:00
cstdlib
Fix _LIBCPP_HAS_ definitions for Android.
2019-11-18 12:19:58 -08:00
cstring
Update the file headers across all of the LLVM projects in the monorepo
2019-01-19 08:50:56 +00:00
ctgmath
Update more file headers across all of the LLVM projects in the monorepo
2019-01-19 10:56:40 +00:00
ctime
Fix _LIBCPP_HAS_ definitions for Android.
2019-11-18 12:19:58 -08:00
ctype.h
Update more file headers across all of the LLVM projects in the monorepo
2019-01-19 10:56:40 +00:00
cwchar
Update more file headers across all of the LLVM projects in the monorepo
2019-01-19 10:56:40 +00:00
cwctype
Update more file headers across all of the LLVM projects in the monorepo
2019-01-19 10:56:40 +00:00
deque
[libc++][P1115][C++20] Improving the Return Value of Erase-Like Algorithms II: Free erase/erase if.
2020-05-02 14:04:50 +02:00
errno.h
Update more file headers across all of the LLVM projects in the monorepo
2019-01-19 10:56:40 +00:00
exception
Fix -Wdeprecated-copy-dtor and -Wdeprecated-dynamic-exception-spec warnings.
2020-03-17 18:59:54 +01:00
execution
[pstl][libc++] Provide uglified header names for interface headers
2019-08-06 21:11:24 +00:00
fenv.h
Mark fenv.h as a system header before the #include_next directive
2019-03-29 16:03:57 +00:00
filesystem
Fix -Wdeprecated-copy-dtor and -Wdeprecated-dynamic-exception-spec warnings.
2020-03-17 18:59:54 +01:00
float.h
Update more file headers across all of the LLVM projects in the monorepo
2019-01-19 10:56:40 +00:00
forward_list
[libc++][P1115][C++20] Improving the Return Value of Erase-Like Algorithms II: Free erase/erase if.
2020-05-02 14:04:50 +02:00
fstream
Open fstream files in O_CLOEXEC mode when possible.
2019-09-16 19:26:41 +00:00
functional
[NFC] Add _EnableIfLValueCallable and move reference out of __callable.
2020-05-19 17:15:28 -07:00
future
Fix -Wdeprecated-copy-dtor and -Wdeprecated-dynamic-exception-spec warnings.
2020-03-17 18:59:54 +01:00
initializer_list
[NFC][libcxx] Remove trailing whitespace
2019-05-29 16:01:36 +00:00
inttypes.h
AIX system headers need stdint.h and inttypes.h to be re-enterable
2019-06-20 15:36:32 +00:00
iomanip
[NFC][libcxx] Remove trailing whitespace
2019-05-29 16:01:36 +00:00
ios
Fix -Wdeprecated-copy-dtor and -Wdeprecated-dynamic-exception-spec warnings.
2020-03-17 18:59:54 +01:00
iosfwd
Update more file headers across all of the LLVM projects in the monorepo
2019-01-19 10:56:40 +00:00
iostream
Update more file headers across all of the LLVM projects in the monorepo
2019-01-19 10:56:40 +00:00
istream
[libc++] Implement LWG 3199
2019-08-20 18:21:06 +00:00
iterator
[libc++] Don't trigger unsigned conversion warnings in std::advance
2020-06-16 13:47:47 -04:00
latch
[libc++] Add availability markup for the C++20 Synchronization Library on Apple
2020-04-06 18:07:26 -04:00
limits
Fix -Wdouble-promotion warnings.
2019-07-01 16:13:31 +00:00
limits.h
Update more file headers across all of the LLVM projects in the monorepo
2019-01-19 10:56:40 +00:00
list
[libc++][P1115][C++20] Improving the Return Value of Erase-Like Algorithms II: Free erase/erase if.
2020-05-02 14:04:50 +02:00
locale
[NFC][libcxx] Remove trailing whitespace
2019-05-29 16:01:36 +00:00
locale.h
Update more file headers across all of the LLVM projects in the monorepo
2019-01-19 10:56:40 +00:00
map
[libc++][P1115][C++20] Improving the Return Value of Erase-Like Algorithms II: Free erase/erase if.
2020-05-02 14:04:50 +02:00
math.h
Reland [libc++] Move abs and div into stdlib.h to fix header cycle.
2020-05-08 21:52:27 +02:00
memory
[NFC] [libcxx] Remove shared_ptr's no-rvalue unique_ptr converting constructor.
2020-06-08 09:49:21 -07:00
module.modulemap
[libc++] Implement <numbers>
2020-06-19 14:25:02 +05:30
mutex
[libc++] Mark __call_once_proxy as hidden and internal
2019-11-11 10:27:48 -05:00
new
[libc++] Revert 03dd205c151 "Adjust max_align_t handling"
2020-02-25 11:42:08 -05:00
numbers
[libc++] Require concepts support for <numbers>
2020-06-19 10:49:44 -04:00
numeric
[libc++] Fix typo in std::midpoint
2019-12-21 01:26:24 -08:00
optional
Add a missing '__uncvref_t' to the SFINAE constraints for optional's assignment operator. Fixes PR38638. Thanks to Jonathan Wakely for the report
2019-06-27 18:40:55 +00:00
ostream
Add forward declaration of operator<< in <string_view> as required.
2019-09-25 18:56:54 +00:00
queue
Rename __is_foo_iterator traits to reflect their Cpp17 nature.
2019-11-18 01:49:32 -05:00
random
[libc++] Bugfix to std::binomial_distribution<int>
2020-03-17 15:56:16 -04:00
ratio
Update more file headers across all of the LLVM projects in the monorepo
2019-01-19 10:56:40 +00:00
regex
[libc++] Fix some typos in the comment header for <regex>
2020-06-25 15:34:51 -04:00
scoped_allocator
Update more file headers across all of the LLVM projects in the monorepo
2019-01-19 10:56:40 +00:00
semaphore
[libc++] Add availability markup for the C++20 Synchronization Library on Apple
2020-04-06 18:07:26 -04:00
set
[libc++][P1115][C++20] Improving the Return Value of Erase-Like Algorithms II: Free erase/erase if.
2020-05-02 14:04:50 +02:00
setjmp.h
Update more file headers across all of the LLVM projects in the monorepo
2019-01-19 10:56:40 +00:00
shared_mutex
Revert "Suppress -Wctad-maybe-unsupported on types w/o deduction guides."
2019-08-04 07:13:43 +00:00
span
[libcxx] Remove swap for std::span
2020-05-20 14:34:21 -04:00
sstream
add a test and a couple minor bug fixes for the implicit-signed-integer-truncation sanitizer. This is PR#40566
2019-02-01 21:59:27 +00:00
stack
[NFC][libcxx] Remove trailing whitespace
2019-05-29 16:01:36 +00:00
stdbool.h
Update more file headers across all of the LLVM projects in the monorepo
2019-01-19 10:56:40 +00:00
stddef.h
Avoid using std::max_align_t in pre-C++11 mode
2020-04-04 01:38:41 +02:00
stdexcept
Fix -Wdeprecated-copy-dtor and -Wdeprecated-dynamic-exception-spec warnings.
2020-03-17 18:59:54 +01:00
stdint.h
AIX system headers need stdint.h and inttypes.h to be re-enterable
2019-06-20 15:36:32 +00:00
stdio.h
Update more file headers across all of the LLVM projects in the monorepo
2019-01-19 10:56:40 +00:00
stdlib.h
Reland [libc++] Move abs and div into stdlib.h to fix header cycle.
2020-05-08 21:52:27 +02:00
streambuf
Update more file headers across all of the LLVM projects in the monorepo
2019-01-19 10:56:40 +00:00
string
Add optimization to basic_string::assign for compile-time known constant values.
2020-06-29 14:34:34 -04:00
string_view
Add forward declaration of operator<< in <string_view> as required.
2019-09-25 18:56:54 +00:00
string.h
Update the file headers across all of the LLVM projects in the monorepo
2019-01-19 08:50:56 +00:00
strstream
Update more file headers across all of the LLVM projects in the monorepo
2019-01-19 10:56:40 +00:00
system_error
Fix -Wdeprecated-copy-dtor and -Wdeprecated-dynamic-exception-spec warnings.
2020-03-17 18:59:54 +01:00
tgmath.h
Update more file headers across all of the LLVM projects in the monorepo
2019-01-19 10:56:40 +00:00
thread
[libc++] Work around gcc/Power9 bug in include/thread
2020-06-10 12:40:43 -04:00
tuple
PR43764: Qualify a couple of calls to forward_as_tuple to be ADL-resilient.
2019-10-28 18:04:41 -07:00
type_traits
[libcxx][type_traits] Add C++20 changes to common_type
2020-05-18 14:06:32 +02:00
typeindex
Update more file headers across all of the LLVM projects in the monorepo
2019-01-19 10:56:40 +00:00
typeinfo
[libc++] Fix the LIBCXX_HAS_MERGED_TYPEINFO_NAMES_DEFAULT setting
2020-05-29 06:14:30 -04:00
unordered_map
[libc++][P1115][C++20] Improving the Return Value of Erase-Like Algorithms II: Free erase/erase if.
2020-05-02 14:04:50 +02:00
unordered_set
[libc++][P1115][C++20] Improving the Return Value of Erase-Like Algorithms II: Free erase/erase if.
2020-05-02 14:04:50 +02:00
utility
Refactor default constructor SFINAE in pair and tuple.
2019-09-30 20:55:30 +00:00
valarray
[libc++] Cleanup and enable multiple warnings.
2019-12-12 21:09:08 -05:00
variant
[libcxx/variant] Fix build error for when exceptions disabled.
2020-06-18 07:21:42 -07:00
vector
Optimize 'construct at end' loops in vector
2020-06-18 13:51:12 -04:00
version
[libc++] Require concepts support for <numbers>
2020-06-19 10:49:44 -04:00
wchar.h
[libc++] Add missing <stddef.h> include to <wchar.h>
2020-06-25 19:27:32 -04:00
wctype.h
Update more file headers across all of the LLVM projects in the monorepo
2019-01-19 10:56:40 +00:00