*: Centralize detection of OS and compiler in golang/runtime/platform.h

Up until now we had scattered ifdef __linux__, ifdef __APPLE__, ifdef
_MSC_VER etc. And in the future we will need to detect more things with
more involved conditions.

-> Factor the code, that detects OS and compiler, into one place as a
preparatory step for that.

MANIFEST.in

@@ -2,6 +2,7 @@ include COPYING README.rst CHANGELOG.rst tox.ini pyproject.toml trun .lsan-ignor
 include golang/libgolang.h
 include golang/runtime/libgolang.cpp
 include golang/runtime/libpyxruntime.cpp
+include golang/runtime/platform.h
 include golang/pyx/runtime.h
 include golang/pyx/testprog/golang_dso_user/dsouser/dso.h
 include golang/pyx/testprog/golang_dso_user/dsouser/dso.cpp

golang/fmt.h

 #ifndef _NXD_LIBGOLANG_FMT_H
 #define _NXD_LIBGOLANG_FMT_H
 
-// Copyright (C) 2019-2023  Nexedi SA and Contributors.
+// Copyright (C) 2019-2024  Nexedi SA and Contributors.
 //                          Kirill Smelkov <kirr@nexedi.com>
 //
 // This program is free software: you can Use, Study, Modify and Redistribute
@@ -111,7 +111,7 @@ inline error errorf(const string& format, Argv... argv) {
 // `const char *` overloads just to catch format mistakes as
 // __attribute__(format) does not work with std::string.
 LIBGOLANG_API string sprintf(const char *format, ...)
-#ifndef _MSC_VER
+#ifndef LIBGOLANG_CC_msc
                                 __attribute__ ((format (printf, 1, 2)))
 #endif
 	;

golang/libgolang.h

@@ -169,6 +169,8 @@
 // [1] Libtask: a Coroutine Library for C and Unix. https://swtch.com/libtask.
 // [2] http://9p.io/magic/man2html/2/thread.
 
+#include "golang/runtime/platform.h"
+
 #include <stdbool.h>
 #include <stddef.h>
 #include <stdint.h>
@@ -177,21 +179,18 @@
 #include <sys/stat.h>
 
 #include <fcntl.h>
-#ifdef _MSC_VER // no mode_t on msvc
+#ifdef LIBGOLANG_CC_msc // no mode_t on msvc
 typedef int mode_t;
 #endif
 
 
 // DSO symbols visibility (based on https://gcc.gnu.org/wiki/Visibility)
-#if defined _WIN32 || defined __CYGWIN__
+#ifdef LIBGOLANG_OS_windows
   #define LIBGOLANG_DSO_EXPORT __declspec(dllexport)
   #define LIBGOLANG_DSO_IMPORT __declspec(dllimport)
-#elif __GNUC__ >= 4
+#else
   #define LIBGOLANG_DSO_EXPORT __attribute__ ((visibility ("default")))
   #define LIBGOLANG_DSO_IMPORT __attribute__ ((visibility ("default")))
-#else
-  #define LIBGOLANG_DSO_EXPORT
-  #define LIBGOLANG_DSO_IMPORT
 #endif
 
 #if BUILDING_LIBGOLANG

golang/os.cpp

-// Copyright (C) 2019-2023  Nexedi SA and Contributors.
+// Copyright (C) 2019-2024  Nexedi SA and Contributors.
 //                          Kirill Smelkov <kirr@nexedi.com>
 //
 // This program is free software: you can Use, Study, Modify and Redistribute
@@ -38,7 +38,7 @@
 // cut this short
 // (on darwing sys_siglist declaration is normally provided)
 // (on windows sys_siglist is not available at all)
-#if !(defined(__APPLE__) || defined(_WIN32))
+#if !(defined(LIBGOLANG_OS_darwin) || defined(LIBGOLANG_OS_windows))
 extern "C" {
     extern const char * const sys_siglist[];
 }
@@ -287,7 +287,7 @@ string Signal::String() const {
     const Signal& sig = *this;
     const char *sigstr = nil;
 
-#ifdef _WIN32
+#ifdef LIBGOLANG_OS_windows
     switch (sig.signo) {
     case SIGABRT:   return "Aborted";
     case SIGBREAK:  return "Break";

golang/os.h

 #ifndef _NXD_LIBGOLANG_OS_H
 #define _NXD_LIBGOLANG_OS_H
 //
-// Copyright (C) 2019-2023  Nexedi SA and Contributors.
+// Copyright (C) 2019-2024  Nexedi SA and Contributors.
 //                          Kirill Smelkov <kirr@nexedi.com>
 //
 // This program is free software: you can Use, Study, Modify and Redistribute
@@ -96,7 +96,7 @@ private:
 // Open opens file @path.
 LIBGOLANG_API std::tuple<File, error> Open(const string &path, int flags = O_RDONLY,
         mode_t mode =
-#if !defined(_MSC_VER)
+#if !defined(LIBGOLANG_CC_msc)
                       S_IRUSR | S_IWUSR | S_IXUSR |
                       S_IRGRP | S_IWGRP | S_IXGRP |
                       S_IROTH | S_IWOTH | S_IXOTH

golang/os/signal.cpp

-// Copyright (C) 2021-2023  Nexedi SA and Contributors.
+// Copyright (C) 2021-2024  Nexedi SA and Contributors.
 //                          Kirill Smelkov <kirr@nexedi.com>
 //
 // This program is free software: you can Use, Study, Modify and Redistribute
@@ -89,7 +89,7 @@
 #include <atomic>
 #include <tuple>
 
-#if defined(_WIN32)
+#if defined(LIBGOLANG_OS_windows)
 # include <windows.h>
 #endif
 
@@ -101,7 +101,7 @@
 #  define debugf(format, ...) do {} while (0)
 #endif
 
-#if defined(_MSC_VER)
+#ifdef LIBGOLANG_CC_msc
 # define HAVE_SIGACTION 0
 #else
 # define HAVE_SIGACTION 1
@@ -194,7 +194,7 @@ void _init() {
     if (err != nil)
         panic("os::newFile(_wakerx");
     _waketx = vfd[1];
-#ifndef _WIN32
+#ifndef LIBGOLANG_OS_windows
     if (sys::Fcntl(_waketx, F_SETFL, O_NONBLOCK) < 0)
         panic("fcntl(_waketx, O_NONBLOCK)");    // TODO +syserr
 #else

golang/pyx/build.py

-# Copyright (C) 2019-2023  Nexedi SA and Contributors.
+# Copyright (C) 2019-2024  Nexedi SA and Contributors.
 #                          Kirill Smelkov <kirr@nexedi.com>
 #
 # This program is free software: you can Use, Study, Modify and Redistribute
@@ -215,6 +215,7 @@ def _with_build_defaults(name, kw):   # -> (pygo, kw')
         'runtime/internal.h',
         'runtime/internal/atomic.h',
         'runtime/internal/syscall.h',
+        'runtime/platform.h',
         'context.h',
         'cxx.h',
         'errors.h',

golang/runtime/internal/atomic.cpp

-// Copyright (C) 2022-2023  Nexedi SA and Contributors.
+// Copyright (C) 2022-2024  Nexedi SA and Contributors.
 //                          Kirill Smelkov <kirr@nexedi.com>
 //
 // This program is free software: you can Use, Study, Modify and Redistribute
@@ -20,7 +20,7 @@
 #include "golang/runtime/internal/atomic.h"
 #include "golang/libgolang.h"
 
-#ifndef _WIN32
+#ifndef LIBGOLANG_OS_windows
 #include <pthread.h>
 #endif
 
@@ -44,7 +44,7 @@ static void _forkNewEpoch() {
 
 void _init() {
 // there is no fork on windows
-#ifndef _WIN32
+#ifndef LIBGOLANG_OS_windows
     int e = pthread_atfork(/*prepare*/nil, /*inparent*/nil, /*inchild*/_forkNewEpoch);
     if (e != 0)
         panic("pthread_atfork failed");

golang/runtime/internal/syscall.cpp

-// Copyright (C) 2021-2023  Nexedi SA and Contributors.
+// Copyright (C) 2021-2024  Nexedi SA and Contributors.
 //                          Kirill Smelkov <kirr@nexedi.com>
 //
 // This program is free software: you can Use, Study, Modify and Redistribute
@@ -58,9 +58,9 @@ string _Errno::Error() {
 
     char ebuf[128];
     bool ok;
-#if __APPLE__
+#ifdef LIBGOLANG_OS_darwin
     ok = (::strerror_r(-e.syserr, ebuf, sizeof(ebuf)) == 0);
-#elif defined(_WIN32)
+#elif defined(LIBGOLANG_OS_windows)
     ok = (::strerror_s(ebuf, sizeof(ebuf), -e.syserr) == 0);
 #else
     char *estr = ::strerror_r(-e.syserr, ebuf, sizeof(ebuf));
@@ -102,7 +102,7 @@ __Errno Close(int fd) {
     return err;
 }
 
-#ifndef _WIN32
+#ifndef LIBGOLANG_OS_windows
 __Errno Fcntl(int fd, int cmd, int arg) {
     int save_errno = errno;
     int err = ::fcntl(fd, cmd, arg);
@@ -124,7 +124,7 @@ __Errno Fstat(int fd, struct ::stat *out_st) {
 
 int Open(const char *path, int flags, mode_t mode) {
     int save_errno = errno;
-#ifdef _WIN32  // default to open files in binary mode
+#ifdef LIBGOLANG_OS_windows  // default to open files in binary mode
     if ((flags & (_O_TEXT | _O_BINARY)) == 0)
         flags |= _O_BINARY;
 #endif
@@ -141,9 +141,9 @@ __Errno Pipe(int vfd[2], int flags) {
         return -EINVAL;
     int save_errno = errno;
     int err;
-#ifdef __linux__
+#ifdef LIBGOLANG_OS_linux
     err = ::pipe2(vfd, flags);
-#elif defined(_WIN32)
+#elif defined(LIBGOLANG_OS_windows)
     err = ::_pipe(vfd, 4096, flags | _O_BINARY);
 #else
     err = ::pipe(vfd);
@@ -167,7 +167,7 @@ out:
     return err;
 }
 
-#ifndef _WIN32
+#ifndef LIBGOLANG_OS_windows
 __Errno Sigaction(int signo, const struct ::sigaction *act, struct ::sigaction *oldact) {
     int save_errno = errno;
     int err = ::sigaction(signo, act, oldact);

golang/runtime/internal/syscall.h

 #ifndef _NXD_LIBGOLANG_RUNTIME_INTERNAL_SYSCALL_H
 #define _NXD_LIBGOLANG_RUNTIME_INTERNAL_SYSCALL_H
 
-// Copyright (C) 2021-2023  Nexedi SA and Contributors.
+// Copyright (C) 2021-2024  Nexedi SA and Contributors.
 //                          Kirill Smelkov <kirr@nexedi.com>
 //
 // This program is free software: you can Use, Study, Modify and Redistribute
@@ -63,13 +63,13 @@ LIBGOLANG_API int/*n|err*/ Read(int fd, void *buf, size_t count);
 LIBGOLANG_API int/*n|err*/ Write(int fd, const void *buf, size_t count);
 
 LIBGOLANG_API __Errno Close(int fd);
-#ifndef _WIN32
+#ifndef LIBGOLANG_OS_windows
 LIBGOLANG_API __Errno Fcntl(int fd, int cmd, int arg);
 #endif
 LIBGOLANG_API __Errno Fstat(int fd, struct ::stat *out_st);
 LIBGOLANG_API int/*fd|err*/ Open(const char *path, int flags, mode_t mode);
 LIBGOLANG_API __Errno Pipe(int vfd[2], int flags);
-#ifndef _WIN32
+#ifndef LIBGOLANG_OS_windows
 LIBGOLANG_API __Errno Sigaction(int signo, const struct ::sigaction *act, struct ::sigaction *oldact);
 #endif
 typedef void (*sighandler_t)(int);

golang/runtime/libgolang.cpp

@@ -52,7 +52,7 @@
 #include <linux/list.h>
 // MSVC does not support statement expressions and typeof
 // -> redo list_entry via C++ lambda.
-#ifdef _MSC_VER
+#ifdef LIBGOLANG_CC_msc
 # undef list_entry
 # define list_entry(ptr, type, member) [&]() {                      \
         const decltype( ((type *)0)->member ) *__mptr = (ptr);      \

golang/runtime/platform.h

+#ifndef _NXD_LIBGOLANG_RUNTIME_PLATFORM_H
+#define _NXD_LIBGOLANG_RUNTIME_PLATFORM_H
+
+// Copyright (C) 2023-2024  Nexedi SA and Contributors.
+//                          Kirill Smelkov <kirr@nexedi.com>
+//
+// This program is free software: you can Use, Study, Modify and Redistribute
+// it under the terms of the GNU General Public License version 3, or (at your
+// option) any later version, as published by the Free Software Foundation.
+//
+// You can also Link and Combine this program with other software covered by
+// the terms of any of the Free Software licenses or any of the Open Source
+// Initiative approved licenses and Convey the resulting work. Corresponding
+// source of such a combination shall include the source code for all other
+// software used.
+//
+// This program is distributed WITHOUT ANY WARRANTY; without even the implied
+// warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
+//
+// See COPYING file for full licensing terms.
+// See https://www.nexedi.com/licensing for rationale and options.
+
+// Header platform.h provides preprocessor defines that describe target platform.
+
+// LIBGOLANG_OS_<X> is defined on operating system X.
+//
+// List of supported operating systems: linux, darwin, windows.
+#ifdef __linux__
+# define LIBGOLANG_OS_linux     1
+#elif defined(__APPLE__)
+# define LIBGOLANG_OS_darwin    1
+#elif defined(_WIN32) || defined(__CYGWIN__)
+# define LIBGOLANG_OS_windows   1
+#else
+# error "unsupported operating system"
+#endif
+
+// LIBGOLANG_CC_<X> is defined on C/C++ compiler X.
+//
+// List of supported compilers: gcc, clang, msc.
+#ifdef __clang__
+# define LIBGOLANG_CC_clang     1
+#elif defined(_MSC_VER)
+# define LIBGOLANG_CC_msc       1
+// NOTE gcc comes last because e.g. clang and icc define __GNUC__ as well
+#elif __GNUC__
+# define LIBGOLANG_CC_gcc       1
+#else
+# error "unsupported compiler"
+#endif
+
+#endif  // _NXD_LIBGOLANG_RUNTIME_PLATFORM_H

setup.py

@@ -241,6 +241,7 @@ setup(
                             'golang/runtime/internal.h',
                             'golang/runtime/internal/atomic.h',
                             'golang/runtime/internal/syscall.h',
+                            'golang/runtime/platform.h',
                             'golang/context.h',
                             'golang/cxx.h',
                             'golang/errors.h',