[gcc r10-9585] libstdc++: Fix bootstrap with -fno-rtti [PR 99077]

[Jonathan Wakely <redi@gcc.gnu.org>]

https://gcc.gnu.org/g:1d5d30410655f21bdeee6c5f2fd970247eea4d23

commit r10-9585-g1d5d30410655f21bdeee6c5f2fd970247eea4d23
Author: Jonathan Wakely <jwakely@redhat.com>
Date:   Fri Feb 12 10:37:56 2021 +0000

    libstdc++: Fix bootstrap with -fno-rtti [PR 99077]
    
    When libstdc++ is built without RTTI the __ios_failure type is just an
    alias for std::ios_failure, so trying to construct it from an int won't
    compile. This changes the RTTI-enabled __ios_failure type to have the
    same constructor parameters as std::ios_failure, so that the constructor
    takes the same arguments whether RTTI is enabled or not.
    
    The __throw_ios_failure function now constructs the error_code, instead
    of the __ios_failure constructor. As a drive-by fix that error_code is
    constructed with std::generic_category() not std::system_category(),
    because the int comes from errno which corresponds to the generic
    category.
    
    libstdc++-v3/ChangeLog:
    
            PR libstdc++/99077
            * src/c++11/cxx11-ios_failure.cc (__ios_failure(const char*, int)):
            Change int parameter to error_code, to match std::ios_failure.
            (__throw_ios_failure(const char*, int)): Construct error_code
            from int parameter.
    
    (cherry picked from commit 4591f7e5329dcc6ee9af2f314a050936d470ab5b)

Diff:
---
 libstdc++-v3/src/c++11/cxx11-ios_failure.cc | 11 +++++------
 1 file changed, 5 insertions(+), 6 deletions(-)

diff --git a/libstdc++-v3/src/c++11/cxx11-ios_failure.cc b/libstdc++-v3/src/c++11/cxx11-ios_failure.cc
index 522573e3381..4339389c35f 100644
--- a/libstdc++-v3/src/c++11/cxx11-ios_failure.cc
+++ b/libstdc++-v3/src/c++11/cxx11-ios_failure.cc
@@ -114,7 +114,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
     __ios_failure(const char* s) : failure(s)
     { __construct_ios_failure(buf, runtime_error::what()); }
 
-    __ios_failure(const char* s, int e) : failure(s, to_error_code(e))
+    __ios_failure(const char* s, const error_code& e) : failure(s, e)
     { __construct_ios_failure(buf, runtime_error::what()); }
 
     ~__ios_failure()
@@ -125,10 +125,6 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
     // There are assertions in src/c++98/ios_failure.cc to ensure the size
     // and alignment assumptions are valid.
     alignas(runtime_error) unsigned char buf[sizeof(runtime_error)];
-
-    static error_code
-    to_error_code(int e)
-    { return e ? error_code(e, system_category()) : io_errc::stream; }
   };
 
   // Custom type info for __ios_failure.
@@ -171,7 +167,10 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
   void
   __throw_ios_failure(const char* str __attribute__((unused)),
 		      int err __attribute__((unused)))
-  { _GLIBCXX_THROW_OR_ABORT(__ios_failure(_(str), err)); }
+  {
+    _GLIBCXX_THROW_OR_ABORT(__ios_failure(_(str),
+	  err ? error_code(err, generic_category()) : io_errc::stream));
+  }
 
 _GLIBCXX_END_NAMESPACE_VERSION
 } // namespace