[gcc(refs/vendors/redhat/heads/gcc-8-branch)] PR libstdc++/68737 Do not use vsnprintf on HPUX

[Jakub Jelinek]

https://gcc.gnu.org/g:467807e5febfeeebc0556d9f9d8b0963cdf4bfad

commit 467807e5febfeeebc0556d9f9d8b0963cdf4bfad
Author: Jonathan Wakely <jwakely@redhat.com>
Date:   Mon Jan 28 23:58:57 2019 +0000

    PR libstdc++/68737 Do not use vsnprintf on HPUX
    
    It doesn't conform to the spec, so use vsprintf with a large buffer
    instead.
    
            PR libstdc++/68737
            * config/locale/generic/c_locale.h (__convert_from_v)
            [_GLIBCXX_USE_C99_STDIO]: Also check _GLIBCXX_HAVE_BROKEN_VSNPRINTF.
            * config/os/hpux/os_defines.h: Define _GLIBCXX_HAVE_BROKEN_VSNPRINTF.
            * include/bits/locale_facets.tcc (num_put::_M_insert_float)
            [_GLIBCXX_USE_C99_STDIO]: Also check _GLIBCXX_HAVE_BROKEN_VSNPRINTF.
    
    (cherry picked from commit c98f255154798847bdd1fc6ce33266c1a1ddc13a)

Diff:
---
 libstdc++-v3/config/locale/generic/c_locale.h | 2 +-
 libstdc++-v3/config/os/hpux/os_defines.h      | 5 +++++
 libstdc++-v3/include/bits/locale_facets.tcc   | 2 +-
 3 files changed, 7 insertions(+), 2 deletions(-)

diff --git a/libstdc++-v3/config/locale/generic/c_locale.h b/libstdc++-v3/config/locale/generic/c_locale.h
index 0d208166063..3045931c840 100644
--- a/libstdc++-v3/config/locale/generic/c_locale.h
+++ b/libstdc++-v3/config/locale/generic/c_locale.h
@@ -70,7 +70,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
     __builtin_va_list __args;
     __builtin_va_start(__args, __fmt);
 
-#if _GLIBCXX_USE_C99_STDIO
+#if _GLIBCXX_USE_C99_STDIO && !_GLIBCXX_HAVE_BROKEN_VSNPRINTF
     const int __ret = __builtin_vsnprintf(__out, __size, __fmt, __args);
 #else
     const int __ret = __builtin_vsprintf(__out, __fmt, __args);
diff --git a/libstdc++-v3/config/os/hpux/os_defines.h b/libstdc++-v3/config/os/hpux/os_defines.h
index 1003477fe35..5a9c4faf75d 100644
--- a/libstdc++-v3/config/os/hpux/os_defines.h
+++ b/libstdc++-v3/config/os/hpux/os_defines.h
@@ -109,4 +109,9 @@ typedef long int __padding_type;
 #if defined (__hppa__)
 #define _GLIBCXX_HAVE_BROKEN_STRTOLD 1
 #endif
+
+// The vnsprintf function returns -1 when the buffer is too small.
+// See PR libstdc++/68737.
+#define _GLIBCXX_HAVE_BROKEN_VSNPRINTF 1
+
 #endif
diff --git a/libstdc++-v3/include/bits/locale_facets.tcc b/libstdc++-v3/include/bits/locale_facets.tcc
index 39da5766075..d5fa91e97d6 100644
--- a/libstdc++-v3/include/bits/locale_facets.tcc
+++ b/libstdc++-v3/include/bits/locale_facets.tcc
@@ -992,7 +992,7 @@ _GLIBCXX_BEGIN_NAMESPACE_LDBL
 	char __fbuf[16];
 	__num_base::_S_format_float(__io, __fbuf, __mod);
 
-#if _GLIBCXX_USE_C99_STDIO
+#if _GLIBCXX_USE_C99_STDIO && !_GLIBCXX_HAVE_BROKEN_VSNPRINTF
 	// Precision is always used except for hexfloat format.
 	const bool __use_prec =
 	  (__io.flags() & ios_base::floatfield) != ios_base::floatfield;