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Do not use packed structures in soft-fp.

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Building for soft-float ColdFire produces an error in soft-fp:

In file included from ../sysdeps/ieee754/soft-fp/s_fmaf.c:42:
../soft-fp/single.h:85:3: error: 'packed' attribute ignored for field of type 'struct <anonymous>' [-Werror=attributes]
   } bits __attribute__ ((packed));
   ^

While this error only appears in that particular case, this attribute
is in fact never useful, on any architecture.  If you have

  struct __attribute__ ((packed)) { ... } bits;

or

  struct { ... } __attribute__ ((packed)) bits;

then the attribute affects the layout of the structure type.  But with
the form used in this code

  struct { ... } bits __attribute__ ((packed));

the field bits is being declared packed, but the layout of its type
has already been determined at that point.  If on any platform the
layout of the sequence of bit-fields were wrong without the use of a
packed attribute, the attribute would need to be used via a definition
of _FP_STRUCT_LAYOUT, not in its present position.

So this patch removes the useless attribute to fix the build for
ColdFire soft-float.  Tested with build-many-glibcs.py that installed
stripped shared libraries are unchanged by the patch.

	* soft-fp/double.h (union _FP_UNION_D): Do not use attribute
	packed on bits.
	* soft-fp/extended.h (union _FP_UNION_E): Likewise.
	* soft-fp/half.h (union _FP_UNION_H): Likewise.
	* soft-fp/quad.h (union _FP_UNION_Q): Likewise.
	* soft-fp/single.h (union _FP_UNION_S): Likewise.
This commit is contained in:
Joseph Myers 2018-02-01 20:44:49 +00:00
parent f1d7368196
commit 049375e2b5
6 changed files with 15 additions and 6 deletions
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9
ChangeLog
View File

@ -1,3 +1,12 @@
2018-02-01 Joseph Myers <joseph@codesourcery.com>
* soft-fp/double.h (union _FP_UNION_D): Do not use attribute
packed on bits.
* soft-fp/extended.h (union _FP_UNION_E): Likewise.
* soft-fp/half.h (union _FP_UNION_H): Likewise.
* soft-fp/quad.h (union _FP_UNION_Q): Likewise.
* soft-fp/single.h (union _FP_UNION_S): Likewise.
2018-02-01 Carlos O'Donell <carlos@redhat.com>
Ramin Seyed-Moussavi <lordrasmus@gmail.com>
Joseph Myers <joseph@codesourcery.com>

4
soft-fp/double.h
View File

@ -89,7 +89,7 @@ union _FP_UNION_D
unsigned exp : _FP_EXPBITS_D;
unsigned sign : 1;
# endif
} bits __attribute__ ((packed));
} bits;
};
# define FP_DECL_D(X) _FP_DECL (2, X)
@ -210,7 +210,7 @@ union _FP_UNION_D
unsigned exp : _FP_EXPBITS_D;
unsigned sign : 1;
# endif
} bits __attribute__ ((packed));
} bits;
};
# define FP_DECL_D(X) _FP_DECL (1, X)

2
soft-fp/extended.h
View File

@ -88,7 +88,7 @@ union _FP_UNION_E
unsigned exp : _FP_EXPBITS_E;
unsigned sign : 1;
# endif /* not bigendian */
} bits __attribute__ ((packed));
} bits;
};

2
soft-fp/half.h
View File

@ -75,7 +75,7 @@ union _FP_UNION_H
unsigned exp : _FP_EXPBITS_H;
unsigned sign : 1;
#endif
} bits __attribute__ ((packed));
} bits;
};
#define FP_DECL_H(X) _FP_DECL (1, X)

2
soft-fp/quad.h
View File

@ -93,7 +93,7 @@ union _FP_UNION_Q
unsigned exp : _FP_EXPBITS_Q;
unsigned sign : 1;
# endif /* not bigendian */
} bits __attribute__ ((packed));
} bits;
};

2
soft-fp/single.h
View File

@ -82,7 +82,7 @@ union _FP_UNION_S
unsigned exp : _FP_EXPBITS_S;
unsigned sign : 1;
#endif
} bits __attribute__ ((packed));
} bits;
};
#define FP_DECL_S(X) _FP_DECL (1, X)