adding CC: Charmaine
Am 12.12.2016 um 06:23 schrieb Edward O'Callaghan:
> Brian/Roland ping?
>
> On 12/07/2016 10:30 AM, Edward O'Callaghan wrote:
>> As per the C spec, it is illegal to alias pointers to different
>> types. This results in undefined behaviour after optimization
>> passes, resulting in very subtle bugs that happen only on a
>> full moon..
>>
>> Use a memcpy() as a well defined coercion between the isomorphic
>> bit-field interpretations of memory.
>>
>> V.2: Use C99 compat STATIC_ASSERT() over C11 static_assert().
>>
>> Signed-off-by: Edward O'Callaghan <funfunc...@folklore1984.net>
>> ---
>> src/gallium/drivers/svga/svgadump/svga_shader_dump.c | 10 +++++++++-
>> 1 file changed, 9 insertions(+), 1 deletion(-)
>>
>> diff --git a/src/gallium/drivers/svga/svgadump/svga_shader_dump.c
>> b/src/gallium/drivers/svga/svgadump/svga_shader_dump.c
>> index 4ee1bf2..46126a5 100644
>> --- a/src/gallium/drivers/svga/svgadump/svga_shader_dump.c
>> +++ b/src/gallium/drivers/svga/svgadump/svga_shader_dump.c
>> @@ -30,6 +30,9 @@
>> * @author Michal Krol <mic...@vmware.com>
>> */
>>
>> +#include <assert.h>
>> +#include <string.h>
>> +
>> #include "svga_shader.h"
>> #include "svga_shader_dump.h"
>> #include "svga_shader_op.h"
>> @@ -413,6 +416,11 @@ dump_dstreg(struct sh_dstreg dstreg,
>>
>> static void dump_srcreg( struct sh_srcreg srcreg, struct sh_srcreg *indreg,
>> const struct dump_info *di )
>> {
>> + struct sh_reg srcreg_sh = {0};
>> + /* bit-fields carefully aligned, ensure they stay that way. */
>> + STATIC_ASSERT(sizeof(struct sh_reg) == sizeof(struct sh_srcreg));
>> + memcpy(&srcreg_sh, &srcreg, sizeof(srcreg_sh));
>> +
>> switch (srcreg.modifier) {
>> case SVGA3DSRCMOD_NEG:
>> case SVGA3DSRCMOD_BIASNEG:
>> @@ -427,7 +435,7 @@ static void dump_srcreg( struct sh_srcreg srcreg, struct
>> sh_srcreg *indreg, cons
>> case SVGA3DSRCMOD_NOT:
>> _debug_printf( "!" );
>> }
>> - dump_reg( *(struct sh_reg *) &srcreg, indreg, di );
>> + dump_reg(srcreg_sh, indreg, di );
>> switch (srcreg.modifier) {
>> case SVGA3DSRCMOD_NONE:
>> case SVGA3DSRCMOD_NEG:
>>
>
_______________________________________________
mesa-dev mailing list
mesa-dev@lists.freedesktop.org
https://lists.freedesktop.org/mailman/listinfo/mesa-dev
