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soft-fp: Support conditional zero-initialization in declarations. 

In the Linux kernel, some architectures have a single function that
uses different kinds of unpacking and packing depending on the
instruction being emulated, meaning it is not readily visible to the
compiler that variables from _FP_DECL and _FP_FRAC_DECL_* macros are
only used in cases where they were initialized.  The existing copy of
soft-fp in the Linux kernel uses zero-initialization to avoid warnings
in this case, so while frowned upon as a warning suppression mechanism
in code built for glibc it seems appropriate to have such
zero-initialization conditional on __KERNEL__.  This patch duly adds
it, via a macro _FP_ZERO_INIT that expands to empty for non-kernel
compilations.

Tested for powerpc-nofpu that installed stripped shared libraries are
unchanged by this patch.

	* soft-fp/soft-fp.h (_FP_ZERO_INIT): New macro.  Define depending
	on [__KERNEL__].
	* soft-fp/op-1.h (_FP_FRAC_DECL_1): Use _FP_ZERO_INIT.
	* soft-fp/op-2.h (_FP_FRAC_DECL_2): Likewise.
	* soft-fp/op-common.h (_FP_DECL): Likewise.
This commit is contained in:
Joseph Myers 2015-03-07 01:39:42 +00:00
parent e0ed2fb40a
commit b838844bc5
5 changed files with 26 additions and 6 deletions
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8
ChangeLog
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@ -1,3 +1,11 @@
2015-03-07 Joseph Myers <joseph@codesourcery.com>
* soft-fp/soft-fp.h (_FP_ZERO_INIT): New macro. Define depending
on [__KERNEL__].
* soft-fp/op-1.h (_FP_FRAC_DECL_1): Use _FP_ZERO_INIT.
* soft-fp/op-2.h (_FP_FRAC_DECL_2): Likewise.
* soft-fp/op-common.h (_FP_DECL): Likewise.
2015-03-06 H.J. Lu <hongjiu.lu@intel.com>
* elf/ifuncdep2.c (global): Replace

2
soft-fp/op-1.h
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@ -30,7 +30,7 @@
License along with the GNU C Library; if not, see
<http://www.gnu.org/licenses/>. */
#define _FP_FRAC_DECL_1(X) _FP_W_TYPE X##_f
#define _FP_FRAC_DECL_1(X) _FP_W_TYPE X##_f _FP_ZERO_INIT
#define _FP_FRAC_COPY_1(D, S) (D##_f = S##_f)
#define _FP_FRAC_SET_1(X, I) (X##_f = I)
#define _FP_FRAC_HIGH_1(X) (X##_f)

3
soft-fp/op-2.h
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@ -30,7 +30,8 @@
License along with the GNU C Library; if not, see
<http://www.gnu.org/licenses/>. */
#define _FP_FRAC_DECL_2(X) _FP_W_TYPE X##_f0, X##_f1
#define _FP_FRAC_DECL_2(X) \
_FP_W_TYPE X##_f0 _FP_ZERO_INIT, X##_f1 _FP_ZERO_INIT
#define _FP_FRAC_COPY_2(D, S) (D##_f0 = S##_f0, D##_f1 = S##_f1)
#define _FP_FRAC_SET_2(X, I) __FP_FRAC_SET_2 (X, I)
#define _FP_FRAC_HIGH_2(X) (X##_f1)

8
soft-fp/op-common.h
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@ -29,10 +29,10 @@
License along with the GNU C Library; if not, see
<http://www.gnu.org/licenses/>. */
#define _FP_DECL(wc, X) \
_FP_I_TYPE X##_c __attribute__ ((unused)); \
_FP_I_TYPE X##_s __attribute__ ((unused)); \
_FP_I_TYPE X##_e __attribute__ ((unused)); \
#define _FP_DECL(wc, X) \
_FP_I_TYPE X##_c __attribute__ ((unused)) _FP_ZERO_INIT; \
_FP_I_TYPE X##_s __attribute__ ((unused)) _FP_ZERO_INIT; \
_FP_I_TYPE X##_e __attribute__ ((unused)) _FP_ZERO_INIT; \
_FP_FRAC_DECL_##wc (X)
/* Test whether the qNaN bit denotes a signaling NaN. */

11
soft-fp/soft-fp.h
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@ -51,6 +51,17 @@
# endif
#endif
/* In the Linux kernel, some architectures have a single function that
uses different kinds of unpacking and packing depending on the
instruction being emulated, meaning it is not readily visible to
the compiler that variables from _FP_DECL and _FP_FRAC_DECL_*
macros are only used in cases where they were initialized. */
#ifdef __KERNEL__
# define _FP_ZERO_INIT = 0
#else
# define _FP_ZERO_INIT
#endif
#define _FP_WORKBITS 3
#define _FP_WORK_LSB ((_FP_W_TYPE) 1 << 3)
#define _FP_WORK_ROUND ((_FP_W_TYPE) 1 << 2)