[uclibc-ng-devel] [PATCH] bits/byteswap-common.h: import recent headers from glibc

[Anthony G. Basile]

On 3/25/16 6:35 AM, Waldemar Brodkorb wrote:
> Hi Anthony,
> Anthony G. Basile wrote,
> 
>> From: "Anthony G. Basile" <blueness at gentoo.org>
>>
>> On systems where uClibc doesn't provide an arch specific byteswap.h,
>> we fall back on bits/byteswap-common.h.  However, there is a bug
>> in this header in the __bswap_constant_64(x) macro.  If, for example,
>> a double is passed, we get "invalid operands to binary &" in which we
>> mismatch a 'double' and 'long long unsigned int'.  The newer glibc
>> headers fix this and so we import them.
> 
> I have an issue with the patch on ARM Cortex-M4 (no MMU).
> 
> Any idea? Compile works fine without your patch.
> 
> /home/wbx/embedded-test/openadk/toolchain_generic-arm_uclibc-ng_cortex_m4_soft_eabi/usr/bin/arm-openadk-uclinux-uclibceabi-gcc
> -c libc/string/arm/memcpy.S -o libc/string/arm/memcpy.o -
> Wall -Wstrict-prototypes -Wstrict-aliasing -funsigned-char
> -fno-builtin -fno-asm -fmerge-all-constants -msoft-float
> -mlittle-endian -mthumb -fno-stack-protector -nostdinc -I./include -
> I./include -include libc-symbols.h -I./libc/sysdeps/linux/arm
> -I./libc/sysdeps/linux -I./ldso/ldso/arm -I./ldso/include -I.
> -DSTATIC -Os -fstrict-aliasing -fwrapv -fno-ident -fhonour-c
> opts -mcpu=cortex-m4 -mfloat-abi=soft -Wl,-elf2flt -Os -pipe
> -fomit-frame-pointer -fno-unwind-tables
> -fno-asynchronous-unwind-tables -mthumb -Wa,-mimplicit-it=thumb
> -mno-thumb-interwork -Wa,-mfloat-abi=soft -I./libc/sysdeps/linux/common -isystem
> /home/wbx/embedded-test/openadk/toolchain_generic-arm_uclibc-ng_cortex_m4_soft_eabi/usr/lib/gcc/arm-openadk-uclinux-uclibc
> eabi/5.3.0/include-fixed -isystem
> /home/wbx/embedded-test/openadk/toolchain_generic-arm_uclibc-ng_cortex_m4_soft_eabi/usr/lib/gcc/arm-openadk-uclinux-uclibceabi/5.3.0/include
> -I/home/w
> bx/embedded-test/openadk/target_generic-arm_uclibc-ng_cortex_m4_soft_eabi/usr/include/
> -DNDEBUG -DIN_LIB=libc -MT libc/string/arm/memcpy.o -MD -MP -MF
> libc/string/arm/.memcpy.o.dep -D_
> _ASSEMBLER__ -Wa,--noexecstack
> ./include/bits/kernel_types.h: Assembler messages:
> ./include/bits/kernel_types.h:10: Error: bad instruction `typedef
> unsigned short __kernel_dev_t'
> ./include/bits/kernel_types.h:11: Error: bad instruction `typedef
> unsigned long __kernel_ino_t'
> ./include/bits/kernel_types.h:12: Error: bad instruction `typedef
> unsigned short __kernel_mode_t'
> ./include/bits/kernel_types.h:13: Error: bad instruction `typedef
> unsigned short __kernel_nlink_t'
> ./include/bits/kernel_types.h:14: Error: bad instruction `typedef
> long __kernel_off_t'
> ./include/bits/kernel_types.h:15: Error: bad instruction `typedef
> int __kernel_pid_t'
> ./include/bits/kernel_types.h:16: Error: bad instruction `typedef
> unsigned short __kernel_ipc_pid_t'
> ./include/bits/kernel_types.h:17: Error: bad instruction `typedef
> unsigned short __kernel_uid_t'
> ./include/bits/kernel_types.h:18: Error: bad instruction `typedef
> unsigned short __kernel_gid_t'
> ./include/bits/kernel_types.h:19: Error: bad instruction `typedef
> unsigned int __kernel_size_t'
> 

Thanks for catching this.  I get what's going on but I'm not sure of an
easy fix.  byteswap.h from glibc introduces #include <bits/types.h>
which in turn includes <bits/kernel_types.h> (ifdef _LIBC), both of
which have typedefs.  This is not a problem when these headers get
included in .c files but they are a problem when they are included in .S
files.  This happens in this case through #include <endian.h> which is
in libc/string/arm/_memcpy.S and and strlen.S.  You have a similar case
with arch=sh.

If you're wondering what glibc does, its header stacking is different
avoiding the issue altogether.

For now I have to withdraw this patch until I figure out a way around
it.  While it is the correct way to address the original issue, it
introduces a regression.  So now I'm thinking of how maybe to edit the
.S files.

-- 
Anthony G. Basile, Ph. D.
Chair of Information Technology
D'Youville College
Buffalo, NY 14201
(716) 829-8197