diff mbox series

Do not use packed structures in soft-fp [committed]

Message ID alpine.DEB.2.20.1802012045280.13065@digraph.polyomino.org.uk
State New
Headers show
Series Do not use packed structures in soft-fp [committed] | expand

Commit Message

Joseph Myers Feb. 1, 2018, 8:46 p.m. UTC 
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.  Committed.

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.
diff mbox series

Patch

diff --git a/soft-fp/double.h b/soft-fp/double.h
index f6c83d7..23d11cc 100644
--- a/soft-fp/double.h
+++ b/soft-fp/double.h
@@ -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)
diff --git a/soft-fp/extended.h b/soft-fp/extended.h
index 102acfc..d279432 100644
--- a/soft-fp/extended.h
+++ b/soft-fp/extended.h
@@ -88,7 +88,7 @@  union _FP_UNION_E
     unsigned exp : _FP_EXPBITS_E;
     unsigned sign : 1;
 # endif /* not bigendian */
-  } bits __attribute__ ((packed));
+  } bits;
 };
 
 
diff --git a/soft-fp/half.h b/soft-fp/half.h
index ea28db6..a1fea7b 100644
--- a/soft-fp/half.h
+++ b/soft-fp/half.h
@@ -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)
diff --git a/soft-fp/quad.h b/soft-fp/quad.h
index 71621f0..9a9e4e7 100644
--- a/soft-fp/quad.h
+++ b/soft-fp/quad.h
@@ -93,7 +93,7 @@  union _FP_UNION_Q
     unsigned exp : _FP_EXPBITS_Q;
     unsigned sign : 1;
 # endif /* not bigendian */
-  } bits __attribute__ ((packed));
+  } bits;
 };
 
 
diff --git a/soft-fp/single.h b/soft-fp/single.h
index 2918f78..d5c4a6d 100644
--- a/soft-fp/single.h
+++ b/soft-fp/single.h
@@ -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)