Remove HAVE_STRERROR

[MaskRay]

Summary

Most systems support strerror_r. For the remaining systems (e.g. MSVC) strerror_s and
strerror can be used as fallbacks. We don't have a supported operating
system/compiler that doesn't provide strerror.

Close https://github.com/llvm/llvm-project/issues/62804

https://github.com/flang-compiler/f18/pull/1068 added a fallback
when strerror is unavailable, but I think the code path is dead.

[serge-sans-paille]

I like the radical approach. We'll revert if someone ever complains about this.

[vzakhari]

Flang change LGTM. Thank you!

flang/runtime/CMakeLists.txt

else ()
     add_compile_definitions(FLANG_LITTLE_ENDIAN=1)
   endif ()
   include_directories(BEFORE
     ${FLANG_SOURCE_DIR}/include)
 endif()
 
 include(CheckCXXSymbolExists)
 include(CheckCXXSourceCompiles)
-check_cxx_symbol_exists(strerror string.h HAVE_STRERROR)
 check_cxx_symbol_exists(strerror_r string.h HAVE_STRERROR_R)
 # Can't use symbol exists here as the function is overloaded in C++
 check_cxx_source_compiles(
   "#include <string.h>
    int main() {
      char buf[4096];
      return strerror_s(buf, 4096, 0);
    }
   "
   HAVE_DECL_STRERROR_S)
 
 check_cxx_compiler_flag(-fno-lto FLANG_RUNTIME_HAS_FNO_LTO_FLAG)
 if (FLANG_RUNTIME_HAS_FNO_LTO_FLAG)
   set(NO_LTO_FLAGS "-fno-lto")
 else()
   set(NO_LTO_FLAGS "")
 endif()
 
-if (NOT (HAVE_STRERROR OR HAVE_STRERROR_R OR HAVE_DECL_STRERROR_S))
-  message(FATAL_ERROR "None of strerror, strerror_r, strerror_s found.")
-endif()
-
 configure_file(config.h.cmake config.h)
 # include_directories is used here instead of target_include_directories
 # because add_flang_library creates multiple objects (STATIC/SHARED, OBJECT)
 # with different names
 include_directories(AFTER ${CMAKE_CURRENT_BINARY_DIR})
 
 append(${NO_LTO_FLAGS} CMAKE_C_FLAGS)
 append(${NO_LTO_FLAGS} CMAKE_CXX_FLAGS)

flang/runtime/io-error.cpp

#if defined(__GLIBC__) && defined(_GNU_SOURCE)
   // glibc defines its own incompatible version of strerror_r
   // which may not use the buffer supplied.
   msg = ::strerror_r(ioStat_, buffer, bufferLength);
 #else
   ok = ::strerror_r(ioStat_, buffer, bufferLength) == 0;
 #endif
 #elif HAVE_DECL_STRERROR_S // "Windows Secure API"
   ok = ::strerror_s(buffer, bufferLength, ioStat_) == 0;
-#elif HAVE_STRERROR
+#else
   // Copy the thread un-safe result of strerror into
   // the buffer as fast as possible to minimize impact
   // of collision of strerror in multiple threads.
   msg = strerror(ioStat_);
-#else
-  // Strange that this system doesn't even have strerror
-  return false;
 #endif
   if (msg) {
     ToFortranDefaultCharacter(buffer, bufferLength, msg);
     return true;
   } else if (ok) {
     std::size_t copied{std::strlen(buffer)};
     if (copied < bufferLength) {
       std::memset(buffer + copied, ' ', bufferLength - copied);
     }
     return true;
   } else {
     return false;
   }
 }
 } // namespace Fortran::runtime::io

llvm/cmake/config-ix.cmake

 check_symbol_exists(mallinfo malloc.h HAVE_MALLINFO)
 check_symbol_exists(mallinfo2 malloc.h HAVE_MALLINFO2)
 check_symbol_exists(malloc_zone_statistics malloc/malloc.h
                     HAVE_MALLOC_ZONE_STATISTICS)
 check_symbol_exists(getrlimit "sys/types.h;sys/time.h;sys/resource.h" HAVE_GETRLIMIT)
 check_symbol_exists(posix_spawn spawn.h HAVE_POSIX_SPAWN)
 check_symbol_exists(pread unistd.h HAVE_PREAD)
 check_symbol_exists(sbrk unistd.h HAVE_SBRK)
-check_symbol_exists(strerror string.h HAVE_STRERROR)
 check_symbol_exists(strerror_r string.h HAVE_STRERROR_R)
 check_symbol_exists(strerror_s string.h HAVE_DECL_STRERROR_S)
 check_symbol_exists(setenv stdlib.h HAVE_SETENV)
 if( PURE_WINDOWS )
   check_symbol_exists(_chsize_s io.h HAVE__CHSIZE_S)
 
   check_function_exists(_alloca HAVE__ALLOCA)
   check_function_exists(__alloca HAVE___ALLOCA)

llvm/include/llvm/Config/config.h.cmake

 #cmakedefine HAVE_SETRLIMIT ${HAVE_SETRLIMIT}
 
 /* Define to 1 if you have the `sigaltstack' function. */
 #cmakedefine HAVE_SIGALTSTACK ${HAVE_SIGALTSTACK}
 
 /* Define to 1 if you have the <signal.h> header file. */
 #cmakedefine HAVE_SIGNAL_H ${HAVE_SIGNAL_H}
 
-/* Define to 1 if you have the `strerror' function. */
-#cmakedefine HAVE_STRERROR ${HAVE_STRERROR}
-
 /* Define to 1 if you have the `strerror_r' function. */
 #cmakedefine HAVE_STRERROR_R ${HAVE_STRERROR_R}
 
 /* Define to 1 if you have the `sysconf' function. */
 #cmakedefine HAVE_SYSCONF ${HAVE_SYSCONF}
 
 /* Define to 1 if you have the <sys/ioctl.h> header file. */
 #cmakedefine HAVE_SYS_IOCTL_H ${HAVE_SYS_IOCTL_H}

llvm/lib/Support/Errno.cpp

#if defined(__GLIBC__) && defined(_GNU_SOURCE)
   str = strerror_r(errnum, buffer, MaxErrStrLen - 1);
 #else
   strerror_r(errnum, buffer, MaxErrStrLen - 1);
   str = buffer;
 #endif
 #elif HAVE_DECL_STRERROR_S // "Windows Secure API"
   strerror_s(buffer, MaxErrStrLen - 1, errnum);
   str = buffer;
-#elif defined(HAVE_STRERROR)
+#else
   // Copy the thread un-safe result of strerror into
   // the buffer as fast as possible to minimize impact
   // of collision of strerror in multiple threads.
   str = strerror(errnum);
-#else
-  // Strange that this system doesn't even have strerror
-  // but, oh well, just use a generic message
-  raw_string_ostream stream(str);
-  stream << "Error #" << errnum;
-  stream.flush();
 #endif
   return str;
 }
 
 }  // namespace sys
 }  // namespace llvm

llvm/utils/gn/secondary/llvm/include/llvm/Config/BUILD.gn

values = [
     "HAVE_FENV_H=1",
     "HAVE_FFI_CALL=",
     "HAVE_FFI_FFI_H=",
     "HAVE_FFI_H=",
     "HAVE_LIBPFM=",
     "HAVE_LIBPSAPI=",
     "HAVE_MALLCTL=",
     "HAVE_SIGNAL_H=1",
-    "HAVE_STRERROR=1",
     "HAVE_SYS_STAT_H=1",
     "HAVE_SYS_TYPES_H=1",
     "HAVE_VALGRIND_VALGRIND_H=",
     "HAVE__ALLOCA=",
     "HAVE___ALLOCA=",
     "HAVE___ASHLDI3=",
     "HAVE___ASHRDI3=",
     "HAVE___CHKSTK=",

utils/bazel/llvm-project-overlay/llvm/include/llvm/Config/config.h

 #define HAVE_SETRLIMIT 1
 
 /* Define to 1 if you have the `sigaltstack' function. */
 #define HAVE_SIGALTSTACK 1
 
 /* Define to 1 if you have the <signal.h> header file. */
 #define HAVE_SIGNAL_H 1
 
-/* Define to 1 if you have the `strerror' function. */
-#define HAVE_STRERROR 1
-
 /* Define to 1 if you have the `strerror_r' function. */
 /* HAVE_STRERROR_R defined in Bazel */
 
 /* Define to 1 if you have the `sysconf' function. */
 #define HAVE_SYSCONF 1
 
 /* Define to 1 if you have the <sys/ioctl.h> header file. */
 #define HAVE_SYS_IOCTL_H 1

utils/bazel/llvm_configs/config.h.cmake

 #cmakedefine HAVE_SETRLIMIT ${HAVE_SETRLIMIT}
 
 /* Define to 1 if you have the `sigaltstack' function. */
 #cmakedefine HAVE_SIGALTSTACK ${HAVE_SIGALTSTACK}
 
 /* Define to 1 if you have the <signal.h> header file. */
 #cmakedefine HAVE_SIGNAL_H ${HAVE_SIGNAL_H}
 
-/* Define to 1 if you have the `strerror' function. */
-#cmakedefine HAVE_STRERROR ${HAVE_STRERROR}
-
 /* Define to 1 if you have the `strerror_r' function. */
 #cmakedefine HAVE_STRERROR_R ${HAVE_STRERROR_R}
 
 /* Define to 1 if you have the `sysconf' function. */
 #cmakedefine HAVE_SYSCONF ${HAVE_SYSCONF}
 
 /* Define to 1 if you have the <sys/ioctl.h> header file. */
 #cmakedefine HAVE_SYS_IOCTL_H ${HAVE_SYS_IOCTL_H}