From b838844bc5028b2b3401af9f0f51687d8a1f8a54 Mon Sep 17 00:00:00 2001 From: Joseph Myers Date: Sat, 7 Mar 2015 01:39:42 +0000 Subject: 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. --- ChangeLog | 8 ++++++++ soft-fp/op-1.h | 2 +- soft-fp/op-2.h | 3 ++- soft-fp/op-common.h | 8 ++++---- soft-fp/soft-fp.h | 11 +++++++++++ 5 files changed, 26 insertions(+), 6 deletions(-) diff --git a/ChangeLog b/ChangeLog index 7f2e14bcd5..a200bcef96 100644 --- a/ChangeLog +++ b/ChangeLog @@ -1,3 +1,11 @@ +2015-03-07 Joseph Myers + + * 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 * elf/ifuncdep2.c (global): Replace diff --git a/soft-fp/op-1.h b/soft-fp/op-1.h index 34c84d01c2..bc9e33bf49 100644 --- a/soft-fp/op-1.h +++ b/soft-fp/op-1.h @@ -30,7 +30,7 @@ License along with the GNU C Library; if not, see . */ -#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) diff --git a/soft-fp/op-2.h b/soft-fp/op-2.h index 94a1c71542..26bdfc093d 100644 --- a/soft-fp/op-2.h +++ b/soft-fp/op-2.h @@ -30,7 +30,8 @@ License along with the GNU C Library; if not, see . */ -#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) diff --git a/soft-fp/op-common.h b/soft-fp/op-common.h index 14fd6cdc96..ee4147602f 100644 --- a/soft-fp/op-common.h +++ b/soft-fp/op-common.h @@ -29,10 +29,10 @@ License along with the GNU C Library; if not, see . */ -#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. */ diff --git a/soft-fp/soft-fp.h b/soft-fp/soft-fp.h index 1eafcb433d..f93a94182b 100644 --- a/soft-fp/soft-fp.h +++ b/soft-fp/soft-fp.h @@ -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) -- cgit v1.2.3