libstdc++: Fix build failures for avr

The avr-libc <errno.h> does not define EOVERFLOW, which means that
std::errc::value_too_large is not defined, and so <charconv> cannot be
compiled. Define value_too_large for avr with a value that does not
clash with any that is defined in <errno.h>. This is a kluge to fix
bootstrap for avr; it can be removed after PR libstdc++/104883 is
resolved.

The avr-libc <errno.h> fails to meet the C and POSIX requirements that
each error macro has a distinct integral value, and is usable in #if
directives. Add a special case for avr to system_error.cc so that only
the valid errors are recognized. Also disable the errno checks in
std::filesystem::remove_all that assume a meaningful value for errno.

On avr-libc <unistd.h> exists but does not define the POSIX functions
needed by std::filesystem, so _GLIBCXX_HAVE_UNISTD_H is not sufficient
to check for basic POSIX APIs. Check !defined __AVR__ as well as
_GLIBCXX_HAVE_UNISTD_H before using those functions. This is a kluge and
we should really have a specific macro that says the required functions
are available.

libstdc++-v3/ChangeLog:

	* config/os/generic/error_constants.h (errc::value_too_large)
	[__AVR__]: Define.
	* src/c++11/system_error.cc
	(system_category::default_error_condition) [__AVR__]: Only match
	recognize values equal to EDOM, ERANGE, ENOSYS and EINTR.
	* src/c++17/fs_ops.cc (fs::current_path) [__AVR__]: Do not use
	getcwd.
	* src/filesystem/ops-common.h [__AVR__]: Do not use POSIX open,
	close etc.

(cherry picked from commit 2d2e163d12f64a5e68f9e0381751ed9d5d6d3617)

diff --git a/libstdc++-v3/config/os/generic/error_constants.h b/libstdc++-v3/config/os/generic/error_constants.h
index 9d01c16ee2711daa822df00a7e8683a7baf22b52..1d37454ba2efa2579de109dc1c0d28887ed58ed2 100644 (file)
--- a/libstdc++-v3/config/os/generic/error_constants.h
+++ b/libstdc++-v3/config/os/generic/error_constants.h
@@ -167,6 +167,8 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
 
 #ifdef EOVERFLOW
       value_too_large =                        EOVERFLOW,
+#elif defined __AVR__
+      value_too_large =                        999,
 #endif
 
       wrong_protocol_type =                    EPROTOTYPE

diff --git a/libstdc++-v3/src/c++11/system_error.cc b/libstdc++-v3/src/c++11/system_error.cc
index 34274387637e7cc94ede926f6898f6bd93b97969..2b5010dbb402b5b7626f3316da51337c2ed9862d 100644 (file)
--- a/libstdc++-v3/src/c++11/system_error.cc
+++ b/libstdc++-v3/src/c++11/system_error.cc
@@ -93,6 +93,16 @@ namespace
       // and system category otherwise.
       switch (ev)
       {
+#if defined __AVR__
+      // avr-libc only defines a few distinct error numbers. Most <errno.h>
+      // constants are not usable in #if directives and have the same value.
+      case EDOM:
+      case ERANGE:
+      case ENOSYS:
+      case EINTR:
+      case 0:
+       return std::error_condition(ev, generic_category_instance.obj);
+#else
       // List of errno macros from [cerrno.syn].
       // C11 only defines EDOM, EILSEQ and ERANGE, the rest are from POSIX.
       // They expand to integer constant expressions with type int,
@@ -339,7 +349,7 @@ namespace
       case EBLAH:
        return std::error_condition(EINVAL, std::generic_category());
        */
-
+#endif
       default:
        return std::error_condition(ev, *this);
       }

diff --git a/libstdc++-v3/src/c++17/fs_ops.cc b/libstdc++-v3/src/c++17/fs_ops.cc
index 481b49d20be2bd638864b078d04701f015934eff..4155b4d64b9c01b77079caab8205211a9de1731d 100644 (file)
--- a/libstdc++-v3/src/c++17/fs_ops.cc
+++ b/libstdc++-v3/src/c++17/fs_ops.cc
@@ -735,7 +735,7 @@ fs::path
 fs::current_path(error_code& ec)
 {
   path p;
-#ifdef _GLIBCXX_HAVE_UNISTD_H
+#if defined _GLIBCXX_HAVE_UNISTD_H && ! defined __AVR__
 #if defined __GLIBC__ || defined _GLIBCXX_FILESYSTEM_IS_WINDOWS
   if (char_ptr cwd = char_ptr{posix::getcwd(nullptr, 0)})
     {

diff --git a/libstdc++-v3/src/filesystem/ops-common.h b/libstdc++-v3/src/filesystem/ops-common.h
index a76a2e6198da55faed015ceb6f8c0283550667e2..54bafff2a9cf14795ada3c0282bcc250b9a73b85 100644 (file)
--- a/libstdc++-v3/src/filesystem/ops-common.h
+++ b/libstdc++-v3/src/filesystem/ops-common.h
@@ -128,7 +128,7 @@ namespace __gnu_posix
     return ret;
   }
   using char_type = wchar_t;
-#elif defined _GLIBCXX_HAVE_UNISTD_H
+#elif defined _GLIBCXX_HAVE_UNISTD_H && ! defined __AVR__
   using ::open;
   using ::close;
 # ifdef _GLIBCXX_HAVE_SYS_STAT_H