[libcxx-commits] [libcxx] e837f4b - [libc++][PSTL] Add a simple std::thread backend
Nikolas Klauser via libcxx-commits
libcxx-commits at lists.llvm.org
Wed May 24 15:34:03 PDT 2023
Author: Nikolas Klauser
Date: 2023-05-24T15:33:58-07:00
New Revision: e837f4b7dbc32f085d0fe86b2de91e1da14afaa6
URL: https://github.com/llvm/llvm-project/commit/e837f4b7dbc32f085d0fe86b2de91e1da14afaa6
DIFF: https://github.com/llvm/llvm-project/commit/e837f4b7dbc32f085d0fe86b2de91e1da14afaa6.diff
LOG: [libc++][PSTL] Add a simple std::thread backend
This is just to test that the PSTL works with parallelization. This is not supposed to be a production-ready backend.
Reviewed By: ldionne, #libc
Spies: EricWF, arichardson, libcxx-commits
Differential Revision: https://reviews.llvm.org/D150284
Added:
libcxx/include/__algorithm/pstl_backends/cpu_backends/thread.h
Modified:
libcxx/CMakeLists.txt
libcxx/include/CMakeLists.txt
libcxx/include/__algorithm/pstl_backend.h
libcxx/include/__algorithm/pstl_backends/cpu_backends/backend.h
libcxx/include/__config
libcxx/include/__config_site.in
libcxx/include/module.modulemap.in
libcxx/test/libcxx/private_headers.verify.cpp
Removed:
################################################################################
diff --git a/libcxx/CMakeLists.txt b/libcxx/CMakeLists.txt
index 3c550d582f14c..d3ed4a82b82d6 100644
--- a/libcxx/CMakeLists.txt
+++ b/libcxx/CMakeLists.txt
@@ -287,6 +287,12 @@ option(LIBCXX_BUILD_EXTERNAL_THREAD_LIBRARY
"Build libc++ with an externalized threading library.
This option may only be set to ON when LIBCXX_ENABLE_THREADS=ON" OFF)
+if (LIBCXX_ENABLE_THREADS)
+ set(LIBCXX_PSTL_CPU_BACKEND "std_thread" CACHE STRING "Which PSTL CPU backend to use")
+else()
+ set(LIBCXX_PSTL_CPU_BACKEND "serial" CACHE STRING "Which PSTL CPU backend to use")
+endif()
+
# Misc options ----------------------------------------------------------------
# FIXME: Turn -pedantic back ON. It is currently off because it warns
# about #include_next which is used everywhere.
@@ -796,6 +802,15 @@ else()
config_define(0 _LIBCPP_ENABLE_ASSERTIONS_DEFAULT)
endif()
+if (LIBCXX_PSTL_CPU_BACKEND STREQUAL "serial")
+ config_define(1 _LIBCPP_PSTL_CPU_BACKEND_SERIAL)
+elseif(LIBCXX_PSTL_CPU_BACKEND STREQUAL "std_thread")
+ config_define(1 _LIBCPP_PSTL_CPU_BACKEND_THREAD)
+else()
+ message(FATAL_ERROR "LIBCXX_PSTL_CPU_BACKEND is set to ${LIBCXX_PSTL_CPU_BACKEND}, which is not a valid backend.
+ Valid backends are: serial, std_thread")
+endif()
+
if (LIBCXX_ABI_DEFINES)
set(abi_defines)
foreach (abi_define ${LIBCXX_ABI_DEFINES})
diff --git a/libcxx/include/CMakeLists.txt b/libcxx/include/CMakeLists.txt
index 4f37014601dc7..1939a5569fe2f 100644
--- a/libcxx/include/CMakeLists.txt
+++ b/libcxx/include/CMakeLists.txt
@@ -78,6 +78,7 @@ set(files
__algorithm/pstl_backends/cpu_backends/find_if.h
__algorithm/pstl_backends/cpu_backends/for_each.h
__algorithm/pstl_backends/cpu_backends/serial.h
+ __algorithm/pstl_backends/cpu_backends/thread.h
__algorithm/pstl_backends/cpu_backends/transform.h
__algorithm/pstl_copy.h
__algorithm/pstl_fill.h
diff --git a/libcxx/include/__algorithm/pstl_backend.h b/libcxx/include/__algorithm/pstl_backend.h
index 9ac8002a3d271..e80bae8a6d0bc 100644
--- a/libcxx/include/__algorithm/pstl_backend.h
+++ b/libcxx/include/__algorithm/pstl_backend.h
@@ -85,7 +85,7 @@ struct __select_backend<std::execution::unsequenced_policy> {
};
# endif
-# if defined(_PSTL_CPU_BACKEND_SERIAL)
+# if defined(_LIBCPP_PSTL_CPU_BACKEND_SERIAL) || defined(_LIBCPP_PSTL_CPU_BACKEND_THREAD)
template <>
struct __select_backend<std::execution::parallel_policy> {
using type = __cpu_backend_tag;
diff --git a/libcxx/include/__algorithm/pstl_backends/cpu_backends/backend.h b/libcxx/include/__algorithm/pstl_backends/cpu_backends/backend.h
index d6b03d282bd3e..e40d16857ba48 100644
--- a/libcxx/include/__algorithm/pstl_backends/cpu_backends/backend.h
+++ b/libcxx/include/__algorithm/pstl_backends/cpu_backends/backend.h
@@ -11,8 +11,10 @@
#include <__config>
-#if defined(_LIBCPP_HAS_NO_THREADS) || defined(_PSTL_CPU_BACKEND_SERIAL)
+#if defined(_LIBCPP_PSTL_CPU_BACKEND_SERIAL)
# include <__algorithm/pstl_backends/cpu_backends/serial.h>
+#elif defined(_LIBCPP_PSTL_CPU_BACKEND_THREAD)
+# include <__algorithm/pstl_backends/cpu_backends/thread.h>
#else
# error "Invalid CPU backend choice"
#endif
diff --git a/libcxx/include/__algorithm/pstl_backends/cpu_backends/thread.h b/libcxx/include/__algorithm/pstl_backends/cpu_backends/thread.h
new file mode 100644
index 0000000000000..967ce8c9acc28
--- /dev/null
+++ b/libcxx/include/__algorithm/pstl_backends/cpu_backends/thread.h
@@ -0,0 +1,43 @@
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___ALGORITHM_PSTL_BACKENDS_CPU_BACKENDS_THREAD_H
+#define _LIBCPP___ALGORITHM_PSTL_BACKENDS_CPU_BACKENDS_THREAD_H
+
+#include <__assert>
+#include <__config>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+# pragma GCC system_header
+#endif
+
+#if !defined(_LIBCPP_HAS_NO_INCOMPLETE_PSTL) && _LIBCPP_STD_VER >= 17
+
+// This backend implementation is for testing purposes only and not meant for production use. This will be replaced
+// by a proper implementation once the PSTL implementation is somewhat stable.
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+namespace __par_backend {
+inline namespace __thread_cpu_backend {
+
+template <class _RandomAccessIterator, class _Fp>
+_LIBCPP_HIDE_FROM_ABI void __parallel_for(_RandomAccessIterator __first, _RandomAccessIterator __last, _Fp __f) {
+ __f(__first, __last);
+}
+
+_LIBCPP_HIDE_FROM_ABI inline void __cancel_execution() {}
+
+} // namespace __thread_cpu_backend
+} // namespace __par_backend
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // !defined(_LIBCPP_HAS_NO_INCOMPLETE_PSTL) && && _LIBCPP_STD_VER >= 17
+
+#endif // _LIBCPP___ALGORITHM_PSTL_BACKENDS_CPU_BACKENDS_THREAD_H
diff --git a/libcxx/include/__config b/libcxx/include/__config
index 6890635467c5c..4a7ca97fd0361 100644
--- a/libcxx/include/__config
+++ b/libcxx/include/__config
@@ -1280,7 +1280,6 @@ __sanitizer_verify_double_ended_contiguous_container(const void*, const void*, c
// TODO: Make this a proper configuration option
#define _PSTL_PAR_BACKEND_SERIAL
-#define _PSTL_CPU_BACKEND_SERIAL
#define _PSTL_PRAGMA(x) _Pragma(# x)
diff --git a/libcxx/include/__config_site.in b/libcxx/include/__config_site.in
index c0f719b357ff6..88f7383f24340 100644
--- a/libcxx/include/__config_site.in
+++ b/libcxx/include/__config_site.in
@@ -32,6 +32,10 @@
#cmakedefine01 _LIBCPP_ENABLE_ASSERTIONS_DEFAULT
#cmakedefine _LIBCPP_ENABLE_DEBUG_MODE
+// PSTL backends
+#cmakedefine _LIBCPP_PSTL_CPU_BACKEND_SERIAL
+#cmakedefine _LIBCPP_PSTL_CPU_BACKEND_THREAD
+
// __USE_MINGW_ANSI_STDIO gets redefined on MinGW
#ifdef __clang__
# pragma clang diagnostic push
diff --git a/libcxx/include/module.modulemap.in b/libcxx/include/module.modulemap.in
index 502c4f68133f7..743fce27f7133 100644
--- a/libcxx/include/module.modulemap.in
+++ b/libcxx/include/module.modulemap.in
@@ -341,6 +341,9 @@ module std [system] {
module pstl_backends_cpu_backends_serial {
private header "__algorithm/pstl_backends/cpu_backends/serial.h"
}
+ module pstl_backends_cpu_backends_thread {
+ private header "__algorithm/pstl_backends/cpu_backends/thread.h"
+ }
module pstl_backends_cpu_backends_transform {
private header "__algorithm/pstl_backends/cpu_backends/transform.h"
}
diff --git a/libcxx/test/libcxx/private_headers.verify.cpp b/libcxx/test/libcxx/private_headers.verify.cpp
index 3cafdeb2a5e53..2c79212175ba4 100644
--- a/libcxx/test/libcxx/private_headers.verify.cpp
+++ b/libcxx/test/libcxx/private_headers.verify.cpp
@@ -121,6 +121,7 @@ END-SCRIPT
#include <__algorithm/pstl_backends/cpu_backends/find_if.h> // expected-error@*:* {{use of private header from outside its module: '__algorithm/pstl_backends/cpu_backends/find_if.h'}}
#include <__algorithm/pstl_backends/cpu_backends/for_each.h> // expected-error@*:* {{use of private header from outside its module: '__algorithm/pstl_backends/cpu_backends/for_each.h'}}
#include <__algorithm/pstl_backends/cpu_backends/serial.h> // expected-error@*:* {{use of private header from outside its module: '__algorithm/pstl_backends/cpu_backends/serial.h'}}
+#include <__algorithm/pstl_backends/cpu_backends/thread.h> // expected-error@*:* {{use of private header from outside its module: '__algorithm/pstl_backends/cpu_backends/thread.h'}}
#include <__algorithm/pstl_backends/cpu_backends/transform.h> // expected-error@*:* {{use of private header from outside its module: '__algorithm/pstl_backends/cpu_backends/transform.h'}}
#include <__algorithm/push_heap.h> // expected-error@*:* {{use of private header from outside its module: '__algorithm/push_heap.h'}}
#include <__algorithm/ranges_adjacent_find.h> // expected-error@*:* {{use of private header from outside its module: '__algorithm/ranges_adjacent_find.h'}}
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