[PATCH v3 1/6] ldbl-128ibm-compat: workaround GCC 9 C++ BZ 90731
Paul E. Murphy
murphyp@linux.vnet.ibm.com
Mon Apr 6 19:12:34 GMT 2020
GCC 9 has a bug (BZ 90731) whereby __typeof does not correctly copy
exception specifiers[1]. Surprisingly, this can be quieted by declaring
"#pragma system_header", or if the headers are installed in a system
directory.
Work around this by using the pragma for any gcc version between
9.0 and 9.2 to ensure tests continue to compile.
[1] Example error from g++ 9.2.1:
In file included from ../include/sys/cdefs.h:3,
from ../include/features.h:465,
from ../bits/libc-header-start.h:33,
from ../math/math.h:27,
from ../include/math.h:7,
from test-math-isinff.cc:21:
../libio/bits/stdio-ldbl.h:25:20: error: declaration of ‘int sprintf(char*, const char*, ...)’ has a different exception specifier
25 | __LDBL_REDIR_DECL (sprintf)
| ^~~~~~~
../misc/sys/cdefs.h:461:26: note: in definition of macro ‘__LDBL_REDIR_DECL’
461 | extern __typeof (name) name __asm (__ASMNAME ("__" #name "ieee128"));
| ^~~~
In file included from ../include/stdio.h:5,
from test-math-isinff.cc:22:
../libio/stdio.h:334:12: note: from previous declaration ‘int sprintf(char*, const char*, ...) throw ()’
334 | extern int sprintf (char *__restrict __s,
| ^~~~~~~
---
include/monetary.h | 8 ++++++++
include/printf.h | 8 ++++++++
include/stdio.h | 10 ++++++++++
include/stdlib.h | 9 +++++++++
include/wchar.h | 9 +++++++++
5 files changed, 44 insertions(+)
diff --git a/include/monetary.h b/include/monetary.h
index 240925e87d..b6da7326c7 100644
--- a/include/monetary.h
+++ b/include/monetary.h
@@ -1,3 +1,11 @@
+/* Workaround BZ 90731 with GCC 9 when using ldbl redirects in C++. */
+#include <bits/floatn.h>
+#if defined __cplusplus && __LONG_DOUBLE_USES_FLOAT128 == 1
+# if __GNUC_PREREQ (9, 0) && !__GNUC_PREREQ (9, 3)
+# pragma GCC system_header
+# endif
+#endif
+
#include <stdlib/monetary.h>
#ifndef _ISOMAC
#include <stdarg.h>
diff --git a/include/printf.h b/include/printf.h
index d051514119..7430f9a833 100644
--- a/include/printf.h
+++ b/include/printf.h
@@ -1,5 +1,13 @@
#ifndef _PRINTF_H
+/* Workaround BZ 90731 with GCC 9 when using ldbl redirects in C++. */
+#include <bits/floatn.h>
+#if defined __cplusplus && __LONG_DOUBLE_USES_FLOAT128 == 1
+# if __GNUC_PREREQ (9, 0) && !__GNUC_PREREQ (9, 3)
+# pragma GCC system_header
+# endif
+#endif
+
#include <stdio-common/printf.h>
# ifndef _ISOMAC
diff --git a/include/stdio.h b/include/stdio.h
index 6718af4108..8ce73c768b 100644
--- a/include/stdio.h
+++ b/include/stdio.h
@@ -2,8 +2,18 @@
# if !defined _ISOMAC && defined _IO_MTSAFE_IO
# include <stdio-lock.h>
# endif
+
+/* Workaround BZ 90731 with GCC 9 when using ldbl redirects in C++. */
+# include <bits/floatn.h>
+# if defined __cplusplus && __LONG_DOUBLE_USES_FLOAT128 == 1
+# if __GNUC_PREREQ (9, 0) && !__GNUC_PREREQ (9, 3)
+# pragma GCC system_header
+# endif
+# endif
+
# include <libio/stdio.h>
# ifndef _ISOMAC
+
# define _LIBC_STDIO_H 1
# include <libio/libio.h>
diff --git a/include/stdlib.h b/include/stdlib.h
index 926f965f69..d1c4d41ba6 100644
--- a/include/stdlib.h
+++ b/include/stdlib.h
@@ -3,6 +3,15 @@
#ifndef _ISOMAC
# include <stddef.h>
#endif
+
+/* Workaround BZ 90731 with GCC 9 when using ldbl redirects in C++. */
+#include <bits/floatn.h>
+#if defined __cplusplus && __LONG_DOUBLE_USES_FLOAT128 == 1
+# if __GNUC_PREREQ (9, 0) && !__GNUC_PREREQ (9, 3)
+# pragma GCC system_header
+# endif
+#endif
+
#include <stdlib/stdlib.h>
/* Now define the internal interfaces. */
diff --git a/include/wchar.h b/include/wchar.h
index 617906eb14..e70d275cad 100644
--- a/include/wchar.h
+++ b/include/wchar.h
@@ -1,4 +1,13 @@
#ifndef _WCHAR_H
+
+/* Workaround BZ 90731 with GCC 9 when using ldbl redirects in C++. */
+# include <bits/floatn.h>
+# if defined __cplusplus && __LONG_DOUBLE_USES_FLOAT128 == 1
+# if __GNUC_PREREQ (9, 0) && !__GNUC_PREREQ (9, 3)
+# pragma GCC system_header
+# endif
+# endif
+
# include <wcsmbs/wchar.h>
# ifndef _ISOMAC
--
2.21.1
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