From: Edward O'Callaghan Date: Tue, 6 Dec 2016 00:28:56 +0000 (+1100) Subject: svga: Fix a strict-aliasing violation in shader dumper X-Git-Url: https://git.libre-soc.org/?a=commitdiff_plain;h=8801734da701d95608e39d829e0a31a191ee68f2;p=mesa.git svga: Fix a strict-aliasing violation in shader dumper 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 Reviewed-by: Charmaine Lee --- diff --git a/src/gallium/drivers/svga/svgadump/svga_shader_dump.c b/src/gallium/drivers/svga/svgadump/svga_shader_dump.c index 4ee1bf2c353..46126a5460d 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 */ +#include +#include + #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: