This reverts commit d1156fcb56891fb1a426c3e8331a51d47f98a1b8.
This patch fixes the reported incorrect formatting changes and adds
tests for them. The performance should be unaffected, since there are no
significant changes required to fix the bugs.
Specifically, a `>` was changed to a `>=` to also add a `+` in the zero
case, and we're checking for zero now before printing the octal and
hexadecimal prefixes.
Closes#131710
This is technically not necessary in most cases to prevent issues with ADL,
but let's be consistent. This allows us to remove the libcpp-qualify-declval
clang-tidy check, which is now enforced by the robust-against-adl clang-tidy check.
This patch separates the destroy algorithms from the primitive
construct_at and destroy_at operations, which are conceptually not
algorithms. This makes it easier to start using these destroy algorithms
from upcoming relocation facilities.
As part of this, it also implements `std::destroy_at` for arrays without
relying on the `std::destroy` algorithm, which is conceptually a
higher-level facility.
This changes the __output_buffer to a new structure. This improves the
performace of std::format, std::format_to, std::format_to_n, and
std::formatted_size.
Some templates in the standard library are illegal to specialize for users
(even if the specialization contains user-defined types). The [[clang::no_specializations]]
attribute allows marking such base templates so that the compiler will
diagnose if users try adding a specialization.
Currently, the library-internal feature test macros are only defined if
the feature is not available, and always have the prefix
`_LIBCPP_HAS_NO_`. This patch changes that, so that they are always
defined and have the prefix `_LIBCPP_HAS_` instead. This changes the
canonical use of these macros to `#if _LIBCPP_HAS_FEATURE`, which means
that using an undefined macro (e.g. due to a missing include) is
diagnosed now. While this is rather unlikely currently, a similar change
in `<__configuration/availability.h>` caught a few bugs. This also
improves readability, since it removes the double-negation of `#ifndef
_LIBCPP_HAS_NO_FEATURE`.
The current patch only touches the macros defined in `<__config>`. If
people are happy with this approach, I'll make a follow-up PR to also
change the macros defined in `<__config_site>`.
This is a re-application of bc6bd3bc1e9 which was reverted in
f11abac6524 because it broke the Clang pre-commit CI.
Original commit message:
This patch rewrites the modulemap to have fewer top-level modules.
Previously, our modulemap had one top level module for each header in
the library, including private headers. This had the well-known problem
of making compilation times terrible, in addition to being somewhat
against the design principles of Clang modules.
This patch provides almost an order of magnitude compilation time
improvement when building modularized code (certainly subject to
variations). For example, including <ccomplex> without a module cache
went from 22.4 seconds to 1.6 seconds, a 14x improvement.
To achieve this, one might be tempted to simply put all the headers in a
single top-level module. Unfortunately, this doesn't work because libc++
provides C compatibility headers (e.g. stdlib.h) which create cycles
when the C Standard Library headers are modularized too. This is
especially tricky since base systems are usually not modularized: as far
as I know, only Xcode 16 beta contains a modularized SDK that makes this
issue visible. To understand it, imagine we have the following setup:
// in libc++'s include/c++/v1/module.modulemap
module std {
header stddef.h
header stdlib.h
}
// in the C library's include/module.modulemap
module clib {
header stddef.h
header stdlib.h
}
Now, imagine that the C library's <stdlib.h> includes <stddef.h>,
perhaps as an implementation detail. When building the `std` module,
libc++'s <stdlib.h> header does `#include_next <stdlib.h>` to get the C
library's <stdlib.h>, so libc++ depends on the `clib` module.
However, remember that the C library's <stdlib.h> header includes
<stddef.h> as an implementation detail. Since the header search paths
for libc++ are (and must be) before the search paths for the C library,
the C library ends up including libc++'s <stddef.h>, which means it
depends on the `std` module. That's a cycle.
To solve this issue, this patch creates one top-level module for each C
compatibility header. The rest of the libc++ headers are located in a
single top-level `std` module, with two main exceptions. First, the
module containing configuration headers (e.g. <__config>) has its own
top-level module too, because those headers are included by the C
compatibility headers.
Second, we create a top-level std_core module that contains several
dependency-free utilities used (directly or indirectly) from the __math
subdirectory. This is needed because __math pulls in a bunch of stuff,
and __math is used from the C compatibility header <math.h>.
As a direct benefit of this change, we don't need to generate an
artificial __std_clang_module header anymore to provide a monolithic
`std` module, since our modulemap does it naturally by construction.
A next step after this change would be to look into whether math.h
really needs to include the contents of __math, and if so, whether
libc++'s math.h truly needs to include the C library's math.h header.
Removing either dependency would break this annoying cycle.
Thanks to Eric Fiselier for pointing out this approach during a recent
meeting. This wasn't viable before some recent refactoring, but wrapping
everything (except the C headers) in a large module is by far the
simplest and the most effective way of doing this.
Fixes#86193
This reverts 3 commits:
45a09d1811d5d6597385ef02ecf2d4b7320c37c5
24bc3244d4e221f4e6740f45e2bf15a1441a3076
bc6bd3bc1e99c7ec9e22dff23b4f4373fa02cae3
The GitHub pre-merge CI has been broken since this PR went in. This
change reverts it to see if I can get the pre-merge CI working again.
This patch rewrites the modulemap to have fewer top-level modules.
Previously, our modulemap had one top level module for each header in
the library, including private headers. This had the well-known problem
of making compilation times terrible, in addition to being somewhat
against the design principles of Clang modules.
This patch provides almost an order of magnitude compilation time
improvement when building modularized code (certainly subject to
variations). For example, including <ccomplex> without a module cache
went from 22.4 seconds to 1.6 seconds, a 14x improvement.
To achieve this, one might be tempted to simply put all the headers in a
single top-level module. Unfortunately, this doesn't work because libc++
provides C compatibility headers (e.g. stdlib.h) which create cycles
when the C Standard Library headers are modularized too. This is
especially tricky since base systems are usually not modularized: as far
as I know, only Xcode 16 beta contains a modularized SDK that makes this
issue visible. To understand it, imagine we have the following setup:
// in libc++'s include/c++/v1/module.modulemap
module std {
header stddef.h
header stdlib.h
}
// in the C library's include/module.modulemap
module clib {
header stddef.h
header stdlib.h
}
Now, imagine that the C library's <stdlib.h> includes <stddef.h>,
perhaps as an implementation detail. When building the `std` module,
libc++'s <stdlib.h> header does `#include_next <stdlib.h>` to get the C
library's <stdlib.h>, so libc++ depends on the `clib` module.
However, remember that the C library's <stdlib.h> header includes
<stddef.h> as an implementation detail. Since the header search paths
for libc++ are (and must be) before the search paths for the C library,
the C library ends up including libc++'s <stddef.h>, which means it
depends on the `std` module. That's a cycle.
To solve this issue, this patch creates one top-level module for each C
compatibility header. The rest of the libc++ headers are located in a
single top-level `std` module, with two main exceptions. First, the
module containing configuration headers (e.g. <__config>) has its own
top-level module too, because those headers are included by the C
compatibility headers.
Second, we create a top-level std_core module that contains several
dependency-free utilities used (directly or indirectly) from the __math
subdirectory. This is needed because __math pulls in a bunch of stuff,
and __math is used from the C compatibility header <math.h>.
As a direct benefit of this change, we don't need to generate an
artificial __std_clang_module header anymore to provide a monolithic
`std` module, since our modulemap does it naturally by construction.
A next step after this change would be to look into whether math.h
really needs to include the contents of __math, and if so, whether
libc++'s math.h truly needs to include the C library's math.h header.
Removing either dependency would break this annoying cycle.
Thanks to Eric Fiselier for pointing out this approach during a recent
meeting. This wasn't viable before some recent refactoring, but wrapping
everything (except the C headers) in a large module is by far the
simplest and the most effective way of doing this.
Fixes#86193
This patch adds a large number of missing includes in the libc++ headers
and the test suite. Those were found as part of the effort to move
towards a mostly monolithic top-level std module.
This re-formats a few headers that had become out-of-sync with respect
to formatting since we ran clang-format on the whole codebase. There's
surprisingly few instances of it.
This adds the new std::enable_nonlocking_formatter_optimization trait in
<format>. This trait will be used in std::print to implement the
performance benefits.
Implements parts of
- P3107R5 - Permit an efficient implementation of ``std::print``
See [LWG4061](https://cplusplus.github.io/LWG/issue4061) and
[P3341R0](https://wg21.link/p3341r0). Effectively reverts commit
36ce0c3b1e581ca310ae7d0cbc6af002cc5d0251.
`libcxx/test/std/utilities/format/format.functions/bug_81590.compile.pass.cpp`
has a `format` function that unexpectedly takes the
`basic_format_context` by value, which is made ill-formed by LWG4061.
This PR changes the function to take the context by reference.
See [LWG4106](https://cplusplus.github.io/LWG/issue4106) and
[P3341R0](https://wg21.link/p3341r0).
The test coverage for the empty state of `basic_format_args` in
`get.pass.cpp` is to be completely removed, because the
non-default-constructibility is covered in `ctor.pass.cpp`.
As time went by, a few files have become mis-formatted w.r.t.
clang-format. This was made worse by the fact that formatting was not
being enforced in extensionless headers. This commit simply brings all
of libcxx/include in-line with clang-format again.
We might have to do this from time to time as we update our clang-format
version, but frankly this is really low effort now that we've formatted
everything once.
The previous patch implemented
- P2713R1 Escaping improvements in std::format
- LWG3965 Incorrect example in [format.string.escaped] p3 for formatting
of combining characters
These changes were correct, but had a size and performance penalty. This
patch improves the size and performance of the previous patch. The
performance is still worse than before since the lookups may require two
property lookups instead of one before implementing the paper. The
changes give a tighter coupling between the Unicode data and the
algorithm. Additional tests are added to notify about changes in future
Unicode updates.
Before
```
-----------------------------------------------------------------------
Benchmark Time CPU Iterations
-----------------------------------------------------------------------
BM_ascii_escaped<char> 110704 ns 110696 ns 6206
BM_unicode_escaped<char> 101371 ns 101374 ns 6862
BM_cyrillic_escaped<char> 63329 ns 63327 ns 11013
BM_japanese_escaped<char> 41223 ns 41225 ns 16938
BM_emoji_escaped<char> 111022 ns 111021 ns 6304
BM_ascii_escaped<wchar_t> 112441 ns 112443 ns 6231
BM_unicode_escaped<wchar_t> 102776 ns 102779 ns 6813
BM_cyrillic_escaped<wchar_t> 58977 ns 58975 ns 11868
BM_japanese_escaped<wchar_t> 36885 ns 36886 ns 18975
BM_emoji_escaped<wchar_t> 115885 ns 115881 ns 6051
```
The first change is to manually encode the entire last area and make a
manual exception for the 240 excluded entries. This reduced the table
from 1077 to 729 entries and gave the following benchmark results.
```
-----------------------------------------------------------------------
Benchmark Time CPU Iterations
-----------------------------------------------------------------------
BM_ascii_escaped<char> 104777 ns 104776 ns 6550
BM_unicode_escaped<char> 96980 ns 96982 ns 7238
BM_cyrillic_escaped<char> 60254 ns 60251 ns 11670
BM_japanese_escaped<char> 44452 ns 44452 ns 15734
BM_emoji_escaped<char> 104557 ns 104551 ns 6685
BM_ascii_escaped<wchar_t> 107456 ns 107454 ns 6505
BM_unicode_escaped<wchar_t> 96219 ns 96216 ns 7301
BM_cyrillic_escaped<wchar_t> 56921 ns 56904 ns 12288
BM_japanese_escaped<wchar_t> 39530 ns 39529 ns 17492
BM_emoji_escaped<wchar_t> 108494 ns 108496 ns 6408
```
An entry in the table can only contain 2048 code points. For larger
ranges there are multiple entries split in chunks with a maximum size of
2048 entries. To encode the entire Unicode code point range 21 bits are
required. The manual part starts at 0x323B0 this means all entries in
the table fit in 18 bits. This allows to allocate 3 additional bits for
the range. This allows entries to have 16384 elements. This range always
avoids splitting the range in multiple chunks.
This reduces the number of table elements from 729 to 711 and gives the
following benchmark results.
```
-----------------------------------------------------------------------
Benchmark Time CPU Iterations
-----------------------------------------------------------------------
BM_ascii_escaped<char> 104289 ns 104289 ns 6619
BM_unicode_escaped<char> 96682 ns 96681 ns 7215
BM_cyrillic_escaped<char> 59673 ns 59673 ns 11732
BM_japanese_escaped<char> 41983 ns 41982 ns 16646
BM_emoji_escaped<char> 104119 ns 104120 ns 6683
BM_ascii_escaped<wchar_t> 104503 ns 104505 ns 6693
BM_unicode_escaped<wchar_t> 93426 ns 93423 ns 7489
BM_cyrillic_escaped<wchar_t> 54858 ns 54859 ns 12742
BM_japanese_escaped<wchar_t> 36385 ns 36384 ns 19259
BM_emoji_escaped<wchar_t> 105608 ns 105610 ns 6592
```
The change increments the size of the lookup table considerably. The
table has an "upper boundary" check. The removal of the code units with
the property Grapheme_Extend=Yes removes the range E0100..E01EF. This
breaks the trailing large continuous section in two parts. This will be
improved in a followup patch.
Implements:
- P2713R1 Escaping improvements in std::format
- LWG3965 Incorrect example in [format.string.escaped] p3 for formatting
of combining characters
```
---------------------------------------------------------
Benchmark Before After
---------------------------------------------------------
BM_ascii_escaped<char> 95696 ns 110704 ns
BM_unicode_escaped<char> 89311 ns 101371 ns
BM_cyrillic_escaped<char> 58633 ns 63329 ns
BM_japanese_escaped<char> 44500 ns 41223 ns
BM_emoji_escaped<char> 99156 ns 111022 ns
BM_ascii_escaped<wchar_t> 92245 ns 112441 ns
BM_unicode_escaped<wchar_t> 80970 ns 102776 ns
BM_cyrillic_escaped<wchar_t> 51253 ns 58977 ns
BM_japanese_escaped<wchar_t> 37252 ns 36885 ns
BM_emoji_escaped<wchar_t> 96226 ns 115885 ns
```
__precision_ is declared as an int32_t which on some hexagon platforms
is defined as a long.
This change fixes errors like the ones below:
In file included from
/local/mnt/workspace/hex/llvm-project/libcxx/test/libcxx/diagnostics/format.nodiscard_extensions.compile.pass.cpp:19:
In file included from
/local/mnt/workspace/hex/obj_runtimes_hex88_qurt_v75_ON_ON_shared/include/c++/v1/format:202:
In file included from
/local/mnt/workspace/hex/obj_runtimes_hex88_qurt_v75_ON_ON_shared/include/c++/v1/__format/format_functions.h:29:
/local/mnt/workspace/hex/obj_runtimes_hex88_qurt_v75_ON_ON_shared/include/c++/v1/__format/formatter_floating_point.h:700:17:
error: no matching function for call to 'max'
700 | int __p = std::max(1, (__specs.__has_precision() ?
__specs.__precision_ : 6));
| ^~~~~~~~
/local/mnt/workspace/hex/obj_runtimes_hex88_qurt_v75_ON_ON_shared/include/c++/v1/__format/formatter_floating_point.h:771:25:
note: in instantiation of function template specialization
'std::__formatter::__format_floating_point<float, char,
std::format_context>' requested here
771 | return __formatter::__format_floating_point(__value, __ctx,
__parser_.__get_parsed_std_specifications(__ctx));
| ^
/local/mnt/workspace/hex/obj_runtimes_hex88_qurt_v75_ON_ON_shared/include/c++/v1/__format/format_functions.h:284:42:
note: in instantiation of function template specialization
'std::__formatter_floating_point<char>::format<float,
std::format_context>' requested here
284 | __ctx.advance_to(__formatter.format(__arg, __ctx));
| ^
/local/mnt/workspace/hex/obj_runtimes_hex88_qurt_v75_ON_ON_shared/include/c++/v1/__format/format_functions.h:429:15:
note: in instantiation of function template specialization
'std::__vformat_to<std::back_insert_iterator<std::string>, char,
std::back_insert_iterator<std::__format::__output_buffer<char>>>'
requested here
429 | return std::__vformat_to(std::move(__out_it), __fmt, __args);
| ^
/local/mnt/workspace/hex/obj_runtimes_hex88_qurt_v75_ON_ON_shared/include/c++/v1/__format/format_functions.h:462:8:
note: in instantiation of function template specialization
'std::vformat_to<std::back_insert_iterator<std::string>>' requested here
462 | std::vformat_to(std::back_inserter(__res), __fmt, __args);
| ^
/local/mnt/workspace/hex/llvm-project/libcxx/test/libcxx/diagnostics/format.nodiscard_extensions.compile.pass.cpp:29:8:
note: in instantiation of function template specialization
'std::vformat<void>' requested here
29 | std::vformat("", std::make_format_args());
| ^
/local/mnt/workspace/hex/obj_runtimes_hex88_qurt_v75_ON_ON_shared/include/c++/v1/__algorithm/max.h:35:1:
note: candidate template ignored: deduced conflicting types for
parameter '_Tp' ('int' vs. 'int32_t' (aka 'long'))
35 | max(_LIBCPP_LIFETIMEBOUND const _Tp& __a, _LIBCPP_LIFETIMEBOUND
const _Tp& __b) {
| ^
/local/mnt/workspace/hex/obj_runtimes_hex88_qurt_v75_ON_ON_shared/include/c++/v1/__algorithm/max.h:43:1:
note: candidate template ignored: could not match
'initializer_list<_Tp>' against 'int'
43 | max(initializer_list<_Tp> __t, _Compare __comp) {
| ^
/local/mnt/workspace/hex/obj_runtimes_hex88_qurt_v75_ON_ON_shared/include/c++/v1/__algorithm/max.h:48:86:
note: candidate function template not viable: requires single argument
'__t', but 2 arguments were provided
48 | _LIBCPP_NODISCARD_EXT inline _LIBCPP_HIDE_FROM_ABI
_LIBCPP_CONSTEXPR_SINCE_CXX14 _Tp max(initializer_list<_Tp> __t) {
| ^ ~~~~~~~~~~~~~~~~~~~~~~~~~
/local/mnt/workspace/hex/obj_runtimes_hex88_qurt_v75_ON_ON_shared/include/c++/v1/__algorithm/max.h:29:1:
note: candidate function template not viable: requires 3 arguments, but
2 were provided
29 | max(_LIBCPP_LIFETIMEBOUND const _Tp& __a, _LIBCPP_LIFETIMEBOUND
const _Tp& __b, _Compare __comp) {
| ^
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
This uses the macro on record types and inline constexpr variables. The
tagged declarations are very likely to change in future versions of
libc++:
- __fields are internal types used to control the formatter's parse
functions which fields to expect. Newer formatters may add new fields.
For example the filesystem::path formatter accepted in the recent Tokyo
meeting added a new 'g' flag, which differs from the 'g' type.
- The Unicode tables. The number of entries in these table likely differ
between Unicode versions. The tables contain only a part of all Unicode
properties. Typically they are stored in a 32-bit entry where some bits
contain the properties and other bits the size of the range. Changes in
the Unicode or C++ algorithms may require more properties to be
available in C++. This may affect the number of bits available in the
range. If needed, other declarations get the macro. This is mainly a
first time to review this approach.
This was originally https://reviews.llvm.org/D143494 where a new macro
_LIBCPP_HIDE_FROM_ABI_TYPE was defined. Testing revealed the existing
macro _LIBCPP_HIDE_FROM_ABI could be used. The "parts" of the macro that
do not affect records are not harmful. Based on this information the
existing macro was used and additional documentation was written.
An immediate colon signifeis that the range-format-spec contains only
range-underlying-spec.
This patch allows this code to compile and run:
```c++
std::println("{::<<9?}", std::span<const char>{"Hello", sizeof "Hello"});
```
Originally, we used __libcpp_verbose_abort to handle assertion failures.
That function was declared from all public headers. Since we don't use
that mechanism anymore, we don't need to declare __libcpp_verbose_abort
from all public headers, and we can clean up a lot of unnecessary
includes.
This patch also moves the definition of the various assertion categories
to the <__assert> header, since we now rely on regular IWYU for these
assertion macros.
rdar://105510916
