gcc4 generates tons of compile-time warnings like:
/tmp/linux-2.4.31/include/linux/byteorder/swab.h:160: warning: type qualifiers ignored on function return type
/tmp/linux-2.4.31/include/linux/byteorder/swab.h:173: warning: type qualifiers ignored on function return type
/tmp/linux-2.4.31/include/linux/byteorder/swab.h:186: warning: type qualifiers ignored on function return type
/tmp/linux-2.4.31/include/linux/byteorder/swab.h:200: warning: type qualifiers ignored on function return type
This is because functions need to use an attribute to declare const-ness.
Simply putting a 'const' in the return type doesn't work.
The fix (backport from 2.6) is to add __attribute_const__ to compiler.h
and s/const/__attribute_const__/ in the offending function declarations.
Signed-off-by: Mikael Pettersson <[email protected]>
fs/hfs/trans.c | 3 ++-
include/asm-i386/byteorder.h | 5 +++--
include/asm-ppc/byteorder.h | 5 +++--
include/asm-ppc/time.h | 3 ++-
include/asm-x86_64/byteorder.h | 5 +++--
include/linux/byteorder/swab.h | 10 ++++++----
include/linux/compiler.h | 6 ++++++
7 files changed, 25 insertions(+), 12 deletions(-)
diff -rupN linux-2.4.31/fs/hfs/trans.c linux-2.4.31.gcc4-const-function-warnings/fs/hfs/trans.c
--- linux-2.4.31/fs/hfs/trans.c 2001-02-22 15:23:47.000000000 +0100
+++ linux-2.4.31.gcc4-const-function-warnings/fs/hfs/trans.c 2005-06-12 11:48:10.000000000 +0200
@@ -33,6 +33,7 @@
#include <linux/hfs_fs_sb.h>
#include <linux/hfs_fs_i.h>
#include <linux/hfs_fs.h>
+#include <linux/compiler.h>
/*================ File-local variables ================*/
@@ -78,7 +79,7 @@ static unsigned char mac2latin_map[128]
*
* Given a hexadecimal digit in ASCII, return the integer representation.
*/
-static inline const unsigned char dehex(char c) {
+static inline __attribute_const__ unsigned char dehex(char c) {
if ((c>='0')&&(c<='9')) {
return c-'0';
}
diff -rupN linux-2.4.31/include/asm-i386/byteorder.h linux-2.4.31.gcc4-const-function-warnings/include/asm-i386/byteorder.h
--- linux-2.4.31/include/asm-i386/byteorder.h 2003-06-14 13:30:27.000000000 +0200
+++ linux-2.4.31.gcc4-const-function-warnings/include/asm-i386/byteorder.h 2005-06-12 11:48:10.000000000 +0200
@@ -2,6 +2,7 @@
#define _I386_BYTEORDER_H
#include <asm/types.h>
+#include <linux/compiler.h>
#ifdef __GNUC__
@@ -10,7 +11,7 @@
#include <linux/config.h>
#endif
-static __inline__ __const__ __u32 ___arch__swab32(__u32 x)
+static __inline__ __attribute_const__ __u32 ___arch__swab32(__u32 x)
{
#ifdef CONFIG_X86_BSWAP
__asm__("bswap %0" : "=r" (x) : "0" (x));
@@ -26,7 +27,7 @@ static __inline__ __const__ __u32 ___arc
/* gcc should generate this for open coded C now too. May be worth switching to
it because inline assembly cannot be scheduled. -AK */
-static __inline__ __const__ __u16 ___arch__swab16(__u16 x)
+static __inline__ __attribute_const__ __u16 ___arch__swab16(__u16 x)
{
__asm__("xchgb %b0,%h0" /* swap bytes */
: "=q" (x)
diff -rupN linux-2.4.31/include/asm-ppc/byteorder.h linux-2.4.31.gcc4-const-function-warnings/include/asm-ppc/byteorder.h
--- linux-2.4.31/include/asm-ppc/byteorder.h 2003-06-14 13:30:28.000000000 +0200
+++ linux-2.4.31.gcc4-const-function-warnings/include/asm-ppc/byteorder.h 2005-06-12 11:48:10.000000000 +0200
@@ -2,6 +2,7 @@
#define _PPC_BYTEORDER_H
#include <asm/types.h>
+#include <linux/compiler.h>
#ifdef __GNUC__
#ifdef __KERNEL__
@@ -50,7 +51,7 @@ extern __inline__ void st_le64(volatile
__asm__ __volatile__ ("stwbrx %1,0,%2" : "=m" (*addr) : "r" (val), "r" (taddr+4));
}
-static __inline__ __const__ __u16 ___arch__swab16(__u16 value)
+static __inline__ __attribute_const__ __u16 ___arch__swab16(__u16 value)
{
__u16 result;
@@ -58,7 +59,7 @@ static __inline__ __const__ __u16 ___arc
return result;
}
-static __inline__ __const__ __u32 ___arch__swab32(__u32 value)
+static __inline__ __attribute_const__ __u32 ___arch__swab32(__u32 value)
{
__u32 result;
diff -rupN linux-2.4.31/include/asm-ppc/time.h linux-2.4.31.gcc4-const-function-warnings/include/asm-ppc/time.h
--- linux-2.4.31/include/asm-ppc/time.h 2003-08-25 20:07:49.000000000 +0200
+++ linux-2.4.31.gcc4-const-function-warnings/include/asm-ppc/time.h 2005-06-12 11:48:10.000000000 +0200
@@ -12,6 +12,7 @@
#include <linux/config.h>
#include <linux/mc146818rtc.h>
#include <linux/threads.h>
+#include <linux/compiler.h>
#include <asm/processor.h>
@@ -57,7 +58,7 @@ static __inline__ void set_dec(unsigned
/* Accessor functions for the timebase (RTC on 601) registers. */
/* If one day CONFIG_POWER is added just define __USE_RTC as 1 */
#ifdef CONFIG_6xx
-extern __inline__ int const __USE_RTC(void) {
+extern __inline__ int __attribute_const__ __USE_RTC(void) {
return (mfspr(SPRN_PVR)>>16) == 1;
}
#else
diff -rupN linux-2.4.31/include/asm-x86_64/byteorder.h linux-2.4.31.gcc4-const-function-warnings/include/asm-x86_64/byteorder.h
--- linux-2.4.31/include/asm-x86_64/byteorder.h 2002-11-30 17:12:31.000000000 +0100
+++ linux-2.4.31.gcc4-const-function-warnings/include/asm-x86_64/byteorder.h 2005-06-12 11:48:10.000000000 +0200
@@ -2,16 +2,17 @@
#define _X86_64_BYTEORDER_H
#include <asm/types.h>
+#include <linux/compiler.h>
#ifdef __GNUC__
-static __inline__ __const__ __u64 ___arch__swab64(__u64 x)
+static __inline__ __attribute_const__ __u64 ___arch__swab64(__u64 x)
{
__asm__("bswapq %0" : "=r" (x) : "0" (x));
return x;
}
-static __inline__ __const__ __u32 ___arch__swab32(__u32 x)
+static __inline__ __attribute_const__ __u32 ___arch__swab32(__u32 x)
{
__asm__("bswapl %0" : "=r" (x) : "0" (x));
return x;
diff -rupN linux-2.4.31/include/linux/byteorder/swab.h linux-2.4.31.gcc4-const-function-warnings/include/linux/byteorder/swab.h
--- linux-2.4.31/include/linux/byteorder/swab.h 2002-11-30 17:12:31.000000000 +0100
+++ linux-2.4.31.gcc4-const-function-warnings/include/linux/byteorder/swab.h 2005-06-12 11:48:10.000000000 +0200
@@ -15,6 +15,8 @@
*
*/
+#include <linux/compiler.h>
+
/* casts are necessary for constants, because we never know how for sure
* how U/UL/ULL map to __u16, __u32, __u64. At least not in a portable way.
*/
@@ -156,7 +158,7 @@
#endif /* OPTIMIZE */
-static __inline__ __const__ __u16 __fswab16(__u16 x)
+static __inline__ __attribute_const__ __u16 __fswab16(__u16 x)
{
return __arch__swab16(x);
}
@@ -169,7 +171,7 @@ static __inline__ void __swab16s(__u16 *
__arch__swab16s(addr);
}
-static __inline__ __const__ __u32 __fswab24(__u32 x)
+static __inline__ __attribute_const__ __u32 __fswab24(__u32 x)
{
return __arch__swab24(x);
}
@@ -182,7 +184,7 @@ static __inline__ void __swab24s(__u32 *
__arch__swab24s(addr);
}
-static __inline__ __const__ __u32 __fswab32(__u32 x)
+static __inline__ __attribute_const__ __u32 __fswab32(__u32 x)
{
return __arch__swab32(x);
}
@@ -196,7 +198,7 @@ static __inline__ void __swab32s(__u32 *
}
#ifdef __BYTEORDER_HAS_U64__
-static __inline__ __const__ __u64 __fswab64(__u64 x)
+static __inline__ __attribute_const__ __u64 __fswab64(__u64 x)
{
# ifdef __SWAB_64_THRU_32__
__u32 h = x >> 32;
diff -rupN linux-2.4.31/include/linux/compiler.h linux-2.4.31.gcc4-const-function-warnings/include/linux/compiler.h
--- linux-2.4.31/include/linux/compiler.h 2004-11-17 18:36:42.000000000 +0100
+++ linux-2.4.31.gcc4-const-function-warnings/include/linux/compiler.h 2005-06-12 11:48:10.000000000 +0200
@@ -27,6 +27,12 @@
#define __attribute_used__ /* not implemented */
#endif /* __GNUC__ */
+#if __GNUC__ > 2 || (__GNUC__ == 2 && __GNUC_MINOR__ >= 96)
+#define __attribute_const__ __attribute__((__const__))
+#else
+#define __attribute_const__ /* unimplemented */
+#endif
+
#if __GNUC__ == 3
#if __GNUC_MINOR__ >= 1
# define inline __inline__ __attribute__((always_inline))
-
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