[libcxx][libc] Hand in Hand PoC with from_chars (#91651)

Implements std::from_chars for float and double.

The implementation uses LLVM-libc to do the real parsing. Since this is
the first time libc

[libcxx][libc] Hand in Hand PoC with from_chars (#91651)

Implements std::from_chars for float and double.

The implementation uses LLVM-libc to do the real parsing. Since this is
the first time libc++
uses LLVM-libc there is a bit of additional infrastructure code. The
patch is based on the
[RFC] Project Hand In Hand (LLVM-libc/libc++ code sharing)

https://discourse.llvm.org/t/rfc-project-hand-in-hand-llvm-libc-libc-code-sharing/77701

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[libc++] Qualifies size_t.

This has been done using the following command

find libcxx/test -type f -exec perl -pi -e 's|^([^/]+?)((?<!::)size_t)|\1std::\2|' \{} \;

And manually removed some fals

[libc++] Qualifies size_t.

This has been done using the following command

find libcxx/test -type f -exec perl -pi -e 's|^([^/]+?)((?<!::)size_t)|\1std::\2|' \{} \;

And manually removed some false positives in std/depr/depr.c.headers.

The `std` module doesn't export `::size_t`, this is a preparation for that module.

Reviewed By: ldionne, #libc, EricWF, philnik

Differential Revision: https://reviews.llvm.org/D146088

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[libc++] Qualifies uint32_t and friends.

This has been done using the following command
find libcxx/test -type f -exec perl -pi -e 's|^([^/]+?)((?<!::)(?<!::u)u?int(_[a-z]+)?[0-9]{1,2}_t)|\1std::\

[libc++] Qualifies uint32_t and friends.

This has been done using the following command
find libcxx/test -type f -exec perl -pi -e 's|^([^/]+?)((?<!::)(?<!::u)u?int(_[a-z]+)?[0-9]{1,2}_t)|\1std::\2|' \{} \;

And manually removed some false positives in std/depr/depr.c.headers.

Reviewed By: ldionne, #libc

Differential Revision: https://reviews.llvm.org/D145880

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[libc++][test] Uses qualified std::uint32_t.

The module std does not provide c-types in the global namespace. This
means all these types need to be fully qualified. This is a first step
to convert t

[libc++][test] Uses qualified std::uint32_t.

The module std does not provide c-types in the global namespace. This
means all these types need to be fully qualified. This is a first step
to convert them by using sed.

Since this is an automated conversion other types like uint64_t are kept
as is.

Note that tests in the directory libcxx/test/std/depr/depr.c.headers
should not be converted automatically. This requires manual attention,
there some test require testing uint32_t in the global namespace. These
test should fail when using the std module, and pass when using the
std.compat module.

A similar issue occurs with atomic, atomic_uint32_t is specified as
using atomic_uint32_t = atomic<uint32_t>; // freestanding
So here too we need to keep the name in the global namespace in the
tests.

Reviewed By: ldionne, #libc

Differential Revision: https://reviews.llvm.org/D145520

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[libc++] Introduce a setting to remove fstream from the library

This allows porting the library to platforms that are able to support
<iostream> but that do not have a notion of a filesystem, and wh

[libc++] Introduce a setting to remove fstream from the library

This allows porting the library to platforms that are able to support
<iostream> but that do not have a notion of a filesystem, and where it
hence doesn't make sense to support std::fstream (and never will).

Also, remove reliance on <fstream> in various tests that didn't
actually need it.

Differential Revision: https://reviews.llvm.org/D138327

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[libc++] Granularize <iterator> includes

Reviewed By: ldionne, #libc

Spies: libcxx-commits, wenlei

Differential Revision: https://reviews.llvm.org/D127445

[libcxx] Make test case fmt specifiers more portable

These printf()s fail to compile like so on hexagon:

.../tools/llvm-top/libcxx/test/std/utilities/charconv/charconv.msvc/test.cpp:94:23: error: f

[libcxx] Make test case fmt specifiers more portable

These printf()s fail to compile like so on hexagon:

.../tools/llvm-top/libcxx/test/std/utilities/charconv/charconv.msvc/test.cpp:94:23: error: format specifies type 'unsigned int' but the argument has type 'unsigned long' [-Werror,-Wformat]
printf("%u ", elem);
~~ ^~~~
%lu
.../tools/llvm-top/libcxx/test/std/utilities/charconv/charconv.msvc/test.cpp:569:56: error: format specifies type 'unsigned int' but the argument has type 'uint32_t' (aka 'unsigned long') [-Werror,-Wformat]
fprintf(stderr, "%s failed for 0x%08X\n", msg, bits);
~~~~ ^~~~
%08lX
.../tools/llvm-top/libcxx/test/std/utilities/charconv/charconv.msvc/test.cpp:1096:43: error: format specifies type 'unsigned int' but the argument has type 'unsigned long' [-Werror,-Wformat]
printf("Randomized test cases: %u\n", PrefixesToTest * Fractions);
~~ ^~~~~~~~~~~~~~~~~~~~~~~~~~
%lu

Differential Revision: https://reviews.llvm.org/D120532

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Microsoft's floating-point to_chars powered by Ryu and Ryu Printf

Microsoft would like to contribute its implementation of floating-point to_chars to libc++. This uses the impossibly fast Ryu and Ry

Microsoft's floating-point to_chars powered by Ryu and Ryu Printf

Microsoft would like to contribute its implementation of floating-point to_chars to libc++. This uses the impossibly fast Ryu and Ryu Printf algorithms invented by Ulf Adams at Google. Upstream repos: https://github.com/microsoft/STL and https://github.com/ulfjack/ryu .

Licensing notes: MSVC's STL is available under the Apache License v2.0 with LLVM Exception, intentionally chosen to match libc++. We've used Ryu under the Boost Software License.

This patch contains minor changes from Jorg Brown at Google, to adapt the code to libc++. He verified that it works in Google's Linux-based environment, but then I applied more changes on top of his, so any compiler errors are my fault. (I haven't tried to build and test libc++ yet.) Please tell me if we need to do anything else in order to follow https://llvm.org/docs/DeveloperPolicy.html#attribution-of-changes .

Notes:

* libc++'s integer charconv is unchanged (except for a small refactoring). MSVC's integer charconv hasn't been tuned for performance yet, so you're not missing anything.
* Floating-point from_chars isn't part of this patch because Jorg found that MSVC's implementation (derived from our CRT's strtod) was slower than Abseil's. If you're unable to use Abseil or another implementation due to licensing or technical considerations, Microsoft would be delighted if you used MSVC's from_chars (and you can just take it, or ask us to provide a patch like this). Ulf is also working on a novel algorithm for from_chars.
* This assumes that float is IEEE 32-bit, double is IEEE 64-bit, and long double is also IEEE 64-bit.
* I have added MSVC's charconv tests (the whole thing: integer/floating from_chars/to_chars), but haven't adapted them to libcxx's harness at all. (These tests will be available in the microsoft/STL repo soon.)
* Jorg added int128 codepaths. These were originally present in upstream Ryu, and I removed them from microsoft/STL purely for performance reasons (MSVC doesn't support int128; Clang on Windows does, but I found that x64 intrinsics were slightly faster).
* The implementation is split into 3 headers. In MSVC's STL, charconv contains only Microsoft-written code. xcharconv_ryu.h contains code derived from Ryu (with significant modifications and additions). xcharconv_ryu_tables.h contains Ryu's large lookup tables (they were sufficiently large to make editing inconvenient, hence the separate file). The xmeow.h convention is MSVC's for internal headers; you may wish to rename them.
* You should consider separately compiling the lookup tables (see https://github.com/microsoft/STL/issues/172 ) for compiler throughput and reduced object file size.
* See https://github.com/StephanTLavavej/llvm-project/commits/charconv for fine-grained history. (If necessary, I can perform some rebase surgery to show you what Jorg changed relative to the microsoft/STL repo; currently that's all fused into the first commit.)

Differential Revision: https://reviews.llvm.org/D70631

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Microsoft's floating-point to_chars powered by Ryu and Ryu Printf

Microsoft would like to contribute its implementation of floating-point to_chars to libc++. This uses the impossibly fast Ryu and Ry

Microsoft's floating-point to_chars powered by Ryu and Ryu Printf

Microsoft would like to contribute its implementation of floating-point to_chars to libc++. This uses the impossibly fast Ryu and Ryu Printf algorithms invented by Ulf Adams at Google. Upstream repos: https://github.com/microsoft/STL and https://github.com/ulfjack/ryu .

Licensing notes: MSVC's STL is available under the Apache License v2.0 with LLVM Exception, intentionally chosen to match libc++. We've used Ryu under the Boost Software License.

This patch contains minor changes from Jorg Brown at Google, to adapt the code to libc++. He verified that it works in Google's Linux-based environment, but then I applied more changes on top of his, so any compiler errors are my fault. (I haven't tried to build and test libc++ yet.) Please tell me if we need to do anything else in order to follow https://llvm.org/docs/DeveloperPolicy.html#attribution-of-changes .

Notes:

* libc++'s integer charconv is unchanged (except for a small refactoring). MSVC's integer charconv hasn't been tuned for performance yet, so you're not missing anything.
* Floating-point from_chars isn't part of this patch because Jorg found that MSVC's implementation (derived from our CRT's strtod) was slower than Abseil's. If you're unable to use Abseil or another implementation due to licensing or technical considerations, Microsoft would be delighted if you used MSVC's from_chars (and you can just take it, or ask us to provide a patch like this). Ulf is also working on a novel algorithm for from_chars.
* This assumes that float is IEEE 32-bit, double is IEEE 64-bit, and long double is also IEEE 64-bit.
* I have added MSVC's charconv tests (the whole thing: integer/floating from_chars/to_chars), but haven't adapted them to libcxx's harness at all. (These tests will be available in the microsoft/STL repo soon.)
* Jorg added int128 codepaths. These were originally present in upstream Ryu, and I removed them from microsoft/STL purely for performance reasons (MSVC doesn't support int128; Clang on Windows does, but I found that x64 intrinsics were slightly faster).
* The implementation is split into 3 headers. In MSVC's STL, charconv contains only Microsoft-written code. xcharconv_ryu.h contains code derived from Ryu (with significant modifications and additions). xcharconv_ryu_tables.h contains Ryu's large lookup tables (they were sufficiently large to make editing inconvenient, hence the separate file). The xmeow.h convention is MSVC's for internal headers; you may wish to rename them.
* You should consider separately compiling the lookup tables (see https://github.com/microsoft/STL/issues/172 ) for compiler throughput and reduced object file size.
* See https://github.com/StephanTLavavej/llvm-project/commits/charconv for fine-grained history. (If necessary, I can perform some rebase surgery to show you what Jorg changed relative to the microsoft/STL repo; currently that's all fused into the first commit.)

Differential Revision: https://reviews.llvm.org/D70631

show more ...