[Mesa-dev] [PATCH 2/3] glsl: Lower UBO and SSBO access in glsl linker

[Kristian Høgsberg]

On Tue, Nov 10, 2015 at 12:09 AM, Iago Toral <itoral at igalia.com> wrote:
> On Mon, 2015-11-09 at 16:52 +0100, Iago Toral wrote:
>> On Wed, 2015-11-04 at 15:33 -0800, Kristian Høgsberg Kristensen wrote:
>> > All GLSL IR consumers run this lowering pass so we can move it to the
>> > linker. This moves the pass up quite a bit, but that's the point: it
>> > needs to run before we throw away information about per-component vector
>> > access.
>> >
>> > Signed-off-by: Kristian Høgsberg Kristensen <krh at bitplanet.net>
>> > ---
>> >  src/glsl/linker.cpp                        | 8 ++++++++
>> >  src/mesa/drivers/dri/i965/brw_link.cpp     | 2 --
>> >  src/mesa/drivers/dri/i965/brw_shader.cpp   | 2 ++
>> >  src/mesa/main/mtypes.h                     | 2 ++
>> >  src/mesa/state_tracker/st_extensions.c     | 1 +
>> >  src/mesa/state_tracker/st_glsl_to_tgsi.cpp | 1 -
>> >  6 files changed, 13 insertions(+), 3 deletions(-)
>> >
>> > diff --git a/src/glsl/linker.cpp b/src/glsl/linker.cpp
>> > index c35d87a..ea6a3f3 100644
>> > --- a/src/glsl/linker.cpp
>> > +++ b/src/glsl/linker.cpp
>> > @@ -4449,6 +4449,14 @@ link_shaders(struct gl_context *ctx, struct gl_shader_program *prog)
>> >
>> >     /* FINISHME: Assign fragment shader output locations. */
>> >
>> > +   for (unsigned i = 0; i < MESA_SHADER_STAGES; i++) {
>> > +      if (prog->_LinkedShaders[i] == NULL)
>> > +    continue;
>> > +
>> > +      if (ctx->Const.ShaderCompilerOptions[i].LowerBufferInterfaceBlocks)
>> > +         lower_ubo_reference(prog->_LinkedShaders[i]);
>> > +   }
>> > +
>>
>> It probably makes more sense to rewrite this loop as:
>>
>> if (ctx->Const.ShaderCompilerOptions[i].LowerBufferInterfaceBlocks) {
>>    for (unsigned i = 0; i < MESA_SHADER_STAGES; i++) {
>>       if (prog->_LinkedShaders[i] != NULL)
>>          lower_ubo_reference(prog->_LinkedShaders[i]);
>>    }
>> }
>>
>> With that change, and assuming that this change is not responsible for
>> the shader-db regressions posted by Jason:
>
> Forget about that, I did not notice that LowerBufferInterfaceBlocks is
> set by stage. You can keep the Rb for the original version.
>
> Iago

Thanks Iago. The shader-db regression  was down to me confusing
ir_type_variable with ir_type_dereference_variable in the
src/glsl/opt_dead_code_local.cpp hunk.

Kristian

>> Reviewed-by: Iago Toral Quiroga <itoral at igalia.com>
>>
>> >  done:
>> >     for (unsigned i = 0; i < MESA_SHADER_STAGES; i++) {
>> >        free(shader_list[i]);
>> > diff --git a/src/mesa/drivers/dri/i965/brw_link.cpp b/src/mesa/drivers/dri/i965/brw_link.cpp
>> > index f1e3860..2991173 100644
>> > --- a/src/mesa/drivers/dri/i965/brw_link.cpp
>> > +++ b/src/mesa/drivers/dri/i965/brw_link.cpp
>> > @@ -157,8 +157,6 @@ process_glsl_ir(gl_shader_stage stage,
>> >                   _mesa_shader_stage_to_abbrev(shader->Stage));
>> >     }
>> >
>> > -   lower_ubo_reference(shader);
>> > -
>> >     bool progress;
>> >     do {
>> >        progress = false;
>> > diff --git a/src/mesa/drivers/dri/i965/brw_shader.cpp b/src/mesa/drivers/dri/i965/brw_shader.cpp
>> > index 4ea297a..5adc986 100644
>> > --- a/src/mesa/drivers/dri/i965/brw_shader.cpp
>> > +++ b/src/mesa/drivers/dri/i965/brw_shader.cpp
>> > @@ -148,6 +148,8 @@ brw_compiler_create(void *mem_ctx, const struct brw_device_info *devinfo)
>> >           compiler->glsl_compiler_options[i].EmitNoIndirectSampler = true;
>> >
>> >        compiler->glsl_compiler_options[i].NirOptions = nir_options;
>> > +
>> > +      compiler->glsl_compiler_options[i].LowerBufferInterfaceBlocks = true;
>> >     }
>> >
>> >     return compiler;
>> > diff --git a/src/mesa/main/mtypes.h b/src/mesa/main/mtypes.h
>> > index d6c1eb8..800ad81 100644
>> > --- a/src/mesa/main/mtypes.h
>> > +++ b/src/mesa/main/mtypes.h
>> > @@ -2874,6 +2874,8 @@ struct gl_shader_compiler_options
>> >      */
>> >     GLboolean OptimizeForAOS;
>> >
>> > +   GLboolean LowerBufferInterfaceBlocks; /**< Lower UBO and SSBO access to intrinsics. */
>> > +
>> >     const struct nir_shader_compiler_options *NirOptions;
>> >  };
>> >
>> > diff --git a/src/mesa/state_tracker/st_extensions.c b/src/mesa/state_tracker/st_extensions.c
>> > index bd7cbcc..bbb9027 100644
>> > --- a/src/mesa/state_tracker/st_extensions.c
>> > +++ b/src/mesa/state_tracker/st_extensions.c
>> > @@ -254,6 +254,7 @@ void st_init_limits(struct pipe_screen *screen,
>> >                                        PIPE_SHADER_CAP_MAX_UNROLL_ITERATIONS_HINT);
>> >
>> >        options->LowerClipDistance = true;
>> > +      options->LowerBufferInterfaceBlocks = true;
>> >     }
>> >
>> >     c->LowerTessLevel = true;
>> > diff --git a/src/mesa/state_tracker/st_glsl_to_tgsi.cpp b/src/mesa/state_tracker/st_glsl_to_tgsi.cpp
>> > index ca00930..9ee6f8f 100644
>> > --- a/src/mesa/state_tracker/st_glsl_to_tgsi.cpp
>> > +++ b/src/mesa/state_tracker/st_glsl_to_tgsi.cpp
>> > @@ -5822,7 +5822,6 @@ st_link_shader(struct gl_context *ctx, struct gl_shader_program *prog)
>> >                           (!ctx->Const.NativeIntegers ? INT_DIV_TO_MUL_RCP : 0) |
>> >                           (options->EmitNoSat ? SAT_TO_CLAMP : 0));
>> >
>> > -      lower_ubo_reference(prog->_LinkedShaders[i]);
>> >        do_vec_index_to_cond_assign(ir);
>> >        lower_vector_insert(ir, true);
>> >        lower_quadop_vector(ir, false);
>>
>
>