On Monday 20 July 2009 23:00, Mike Frysinger wrote:
> > With attached config, and i486-linux-uclibc-XXX
> > toolchain, it works for me.
> >
> > Can you send me your .config, preprocessed source
> > and gcc command line which gives you trouble?
> >
> > What does your gcc -v say?
>
> defconfig i386, then enable DODEBUG and DODEBUG_PT. using gcc-4.1.1.
Thanks. The offending gcc command line is:
gcc -c libc/stdio/_fwrite.c -o libc/stdio/_fwrite.os -include
./include/libc-symbols.h \
-Wall -Wstrict-prototypes -fno-strict-aliasing -Wnested-externs -Wshadow
-Wmissing-noreturn \
-Wmissing-format-attribute -Wformat=2 -Wmissing-prototypes
-Wmissing-declarations -Wnonnull \
-Wundef -funsigned-char -fno-builtin -fno-asm -std=gnu99 -ffunction-sections
-fdata-sections \
-m32 -fno-stack-protector -nostdinc -I./include -I. -I./libc/sysdeps/linux/i386
-DUCLIBC_INTERNAL \
\
-O0 \
\
-g3 -I./libpthread/linuxthreads.old/sysdeps/unix/sysv/linux/i386 \
-I./libpthread/linuxthreads.old/sysdeps/i386
-I./libpthread/linuxthreads.old/sysdeps/unix/sysv/linux \
-I./libpthread/linuxthreads.old/sysdeps/pthread -I./libpthread/linuxthreads.old
\
-I./libpthread -I/usr/include/ \
-isystem
/.share/usr/app/gcc-4.2.1/bin/../lib/gcc/i386-pc-linux-gnu/4.2.1/include-fixed \
-isystem
/.share/usr/app/gcc-4.2.1/bin/../lib/gcc/i386-pc-linux-gnu/4.2.1/include
-DNDEBUG \
-fPIC -MT libc/stdio/_fwrite.os -MD -MP -MF libc/stdio/._fwrite.os.dep
-O0 is the problem, gcc becomes much dumber.
Please try attached patch. For me it compiles. Resulting code
from memchr(buffer, '\n', pending):
...
132: c7 45 e8 0a 00 00 00 movl $0xa,-0x18(%ebp) <=== !
139: 8b 45 dc mov -0x24(%ebp),%eax
13c: 89 45 e4 mov %eax,-0x1c(%ebp)
13f: 8b 7d ec mov -0x14(%ebp),%edi
142: 8b 45 e8 mov -0x18(%ebp),%eax <=== wow!
145: 8b 4d e4 mov -0x1c(%ebp),%ecx
148: e3 07 jecxz 151 <__stdio_fwrite+0x151>
14a: f2 ae repnz scas %es:(%edi),%al
14c: 8d 7f ff lea -0x1(%edi),%edi
14f: 74 02 je 153 <__stdio_fwrite+0x153>
151: 31 ff xor %edi,%edi
...
--
vda
diff -d -urpN uClibc.6/libc/string/i386/string.h uClibc.7/libc/string/i386/string.h
--- uClibc.6/libc/string/i386/string.h 2009-07-20 21:53:21.000000000 +0200
+++ uClibc.7/libc/string/i386/string.h 2009-07-21 00:36:37.000000000 +0200
@@ -288,6 +288,7 @@ void *inlined_memchr(const void *s, int
static __always_inline
void *inlined_memchr_const_c(const void *s, int c, size_t count)
{
+#if defined __OPTIMIZE__
void *edi;
int ecx, eax;
__asm__ __volatile__(
@@ -304,6 +305,27 @@ void *inlined_memchr_const_c(const void
/* : no clobbers */
);
return edi;
+#else
+ /* With -O0, gcc can't figure out how to encode CONST c
+ * as an immediate operand. Generating slightly bigger code
+ * (usually "movl CONST,%eax", 3 bytes bigger than needed):
+ */
+ void *edi;
+ int ecx, eax;
+ __asm__ __volatile__(
+ " jecxz 1f\n"
+ " repne; scasb\n"
+ " leal -1(%%edi), %%edi\n"
+ " je 2f\n"
+ "1:\n"
+ " xorl %%edi, %%edi\n"
+ "2:\n"
+ : "=&D" (edi), "=&c" (ecx), "=&a" (eax)
+ : "0" (s), "2" (c), "1" (count)
+ /* : no clobbers */
+ );
+ return edi;
+#endif
}
#if 1 /* +2 bytes on shared i386 build with gcc 4.3.0 */
#define memchr(s, c, count) ( \
_______________________________________________
uClibc mailing list
[email protected]
http://lists.busybox.net/mailman/listinfo/uclibc
