Re: grub/head build with pre-release GCC10 ; fail @ "grub-core/disk/mdraid1x_linux.c:181:15: error: ..."

[PGNet Dev]

Thomas,


On 3/24/20 7:51 AM, Paul Menzel wrote:
> Dear PGNet Dev,
> 
> 
> Already reported and analyzed [1]. It’d be nice, if you could verify Thomas’ 
> analysis.

not sure I'm reading your intent from your post,

>       ...
>       I think that the following expression produces the same number without
>       virtual access to a virtual array member:
>
>                (char *) &sb.dev_roles - (char *) sb
>                + grub_le_to_cpu32 (sb.dev_number) * sizeof(grub_uint16_t)
>       ...

with this,

        diff -ur grub.ORIG/grub-core/disk/mdraid1x_linux.c 
grub/grub-core/disk/mdraid1x_linux.c
        --- grub.ORIG/grub-core/disk/mdraid1x_linux.c   2020-03-24 
09:24:08.656640265 -0700
        +++ grub/grub-core/disk/mdraid1x_linux.c        2020-03-24 
09:25:20.615871693 -0700
        @@ -178,8 +178,9 @@
                return NULL;
         
               if (grub_disk_read (disk, sector, 
        -                         (char *) &sb.dev_roles[grub_le_to_cpu32 
(sb.dev_number)]
        -                         - (char *) &sb,
        +                         (char *) &sb.dev_roles
        +                         - (char *) sb
        +                         + grub_le_to_cpu32 (sb.dev_number) * 
sizeof(grub_uint16_t),
                                  sizeof (role), &role))
                return NULL;
 

I'm seeing,

        ...
        gcc -DHAVE_CONFIG_H -I.  -Wall -W -DGRUB_UTIL=1 -D_FILE_OFFSET_BITS=64 
-I./include -DGRUB_FILE=\"grub-core/disk/mdraid1x_linux.c\" -I. -I. -I. -I. 
-I./include -I./include -I./grub-core/lib/libgcrypt-grub/src/  
-I./grub-core/lib/minilzo -I./grub-core/lib/xzembed -I./grub-core/lib/zstd 
-DMINILZO_HAVE_CONFIG_H -O3 -Wall -fstack-protector-strong -funwind-tables 
-fasynchronous-unwind-tables -fmessage-length=0 -grecord-gcc-switches 
-march=native -mtune=native -D_FORTIFY_SOURCE=2 -D_FILE_OFFSET_BITS=64 -Wall -W 
-Wshadow -Wpointer-arith -Wundef -Wchar-subscripts -Wcomment 
-Wdeprecated-declarations -Wdisabled-optimization -Wdiv-by-zero -Wfloat-equal 
-Wformat-extra-args -Wformat-security -Wformat-y2k -Wimplicit 
-Wimplicit-function-declaration -Wimplicit-int -Wmain -Wmissing-braces 
-Wmissing-format-attribute -Wmultichar -Wparentheses -Wreturn-type 
-Wsequence-point -Wshadow -Wsign-compare -Wswitch -Wtrigraphs -Wunknown-pragmas 
-Wunused -Wunused-function -Wunused-label -Wunused-parameter -Wunused-value  
-Wunused-variable -Wwrite-strings -Wnested-externs -Wstrict-prototypes 
-Wcast-align  -Wextra -Wattributes -Wendif-labels -Winit-self 
-Wint-to-pointer-cast -Winvalid-pch -Wmissing-field-initializers -Wnonnull 
-Woverflow -Wvla -Wpointer-to-int-cast -Wstrict-aliasing -Wvariadic-macros 
-Wvolatile-register-var -Wpointer-sign -Wmissing-include-dirs 
-Wmissing-prototypes -Wmissing-declarations -Wformat=2 -Werror  -fno-builtin 
-Wno-undef -O3 -Wall -fstack-protector-strong -funwind-tables 
-fasynchronous-unwind-tables -fmessage-length=0 -grecord-gcc-switches 
-march=native -mtune=native -MT grub-core/disk/libgrubmods_a-mdraid1x_linux.o 
-MD -MP -MF grub-core/disk/.deps-util/libgrubmods_a-mdraid1x_linux.Tpo -c -o 
grub-core/disk/libgrubmods_a-mdraid1x_linux.o `test -f 
'grub-core/disk/mdraid1x_linux.c' || echo './'`grub-core/disk/mdraid1x_linux.c
        grub-core/disk/mdraid1x_linux.c: In function ‘grub_mdraid_detect’:
        grub-core/disk/mdraid1x_linux.c:183:6: error: cannot convert to a 
pointer type
          183 |      + grub_le_to_cpu32 (sb.dev_number) * sizeof(grub_uint16_t),
              |      ^
        make[2]: *** [Makefile:7059: 
grub-core/disk/libgrubmods_a-mdraid1x_linux.o] Error 1

my patch attempt wrong? or still needs tweaks?