[Mesa-dev] [PATCH 7/7] nir: add helper macros for running NIR passes

Rob Clark robdclark at gmail.com
Wed Oct 28 12:56:41 PDT 2015


On Wed, Oct 28, 2015 at 3:40 PM, Jason Ekstrand <jason at jlekstrand.net> wrote:
> On Wed, Oct 28, 2015 at 10:37 AM, Rob Clark <robdclark at gmail.com> wrote:
>> On Wed, Oct 28, 2015 at 12:09 PM, Jason Ekstrand <jason at jlekstrand.net> wrote:
>>> On Sat, Oct 24, 2015 at 10:08 AM, Rob Clark <robdclark at gmail.com> wrote:
>>>> From: Rob Clark <robclark at freedesktop.org>
>>>>
>>>> Convenient place to put in some extra sanity checking, without making
>>>> things messy for the drivers running the passes.
>>>
>>> In the short-term this seems to work (at least for testing nir_clone).
>>> In the long-term, I'm not sure that a macro is really what we want.
>>> I've mentioned a time or two before that what I *think* I'd like to do
>>> (don't know exactly how it will work out yet) is to have a little
>>> datastructure
>>>
>>> typedef struct nir_pass {
>>>    bool (*shader_pass_func)(nir_shader *shader, void *data);
>>>    bool (*impl_pass_func)(nir_function_impl *impl, void *data);
>>>    nir_metadata metadata_preserved;
>>>    void *data;
>>> } nir_pass;
>>>
>>> and have each of the passes expose one of these as a const global
>>> variable instead of exposing the actual functions.  Then we would have
>>> a runner function (or macro) that could run a pass.  The runner would
>>> take care of validation, trashing metadata, and maybe even cloning.
>>> If no shader_pass_func is provided but you call it on a shader, the
>>> runner would iterate over all of the overloads for you and run the
>>> impl_pass_func on each.  We could also have helpers that take an array
>>> and run all of them or even take an array and run it in a loop until
>>> no more progress is made.
>>
>> meh, once we collapse the run+validate into a single line macro call,
>> having list of calls sounds like it doesn't really take up more lines
>> of code compared to a table of nir passes.. plus old fashioned code
>> has a lot more flexibility without having to reinvent loops and ifs
>> and that sort of thing.  Keep in mind some passes are conditional on
>> draw state (ie. what we are lowering) or shader stage, etc.
>
> Really, colapsing run+validate is only part of the desire there.  The
> bigger thing is that it moves metadata invalidation out of the passes.
> This makes it much harder to forget (I found 3 or 4 passes that do it
> wrong today).

not a bad thing.. but could also just be a nir_pass_helper type thing,
I suppose..

> This really doesn't change what you can do.  If you look at my branch
> (which I'm about to send out), the only real difference between
> NIR_PASS() and nir_shader_run_pass is that one is longer and
> lower-case.  You can't wholesale replace the shader, but that seems
> like something we only care about for testing cloning.

I think it is important to have testibility for clone built-in for
debug builds, and easy to enable w/out hacks/recompile.  And the macro
approach is nice for dealing with stages that require extra args, so
we get better validate/clone coverage.

BR,
-R

> The thing I haven't quite settled on is how to pass extra parameters.
>>> For some passes, we could just put the extra stuff in compiler_options
>>> but we don't want to litter it too bad.  The other option is to do
>>> what I did above and use the classic void pointer.  Then drivers would
>>> have to just make a copy and set the data pointer to whatever they
>>> want.
>>>
>>> Maybe I should just go implement this...
>>>
>>>> TODO: convert ir3/vc4..
>>>>
>>>> Signed-off-by: Rob Clark <robclark at freedesktop.org>
>>>> ---
>>>>  src/glsl/nir/nir.h                  |  33 ++++++++++
>>>>  src/mesa/drivers/dri/i965/brw_nir.c | 126 ++++++++++++------------------------
>>>>  2 files changed, 76 insertions(+), 83 deletions(-)
>>>>
>>>> diff --git a/src/glsl/nir/nir.h b/src/glsl/nir/nir.h
>>>> index 3ab720b..053420d 100644
>>>> --- a/src/glsl/nir/nir.h
>>>> +++ b/src/glsl/nir/nir.h
>>>> @@ -1939,10 +1939,43 @@ nir_shader_mutable(nir_shader *shader)
>>>>
>>>>  #ifdef DEBUG
>>>>  void nir_validate_shader(nir_shader *shader);
>>>> +static inline bool
>>>> +__nir_test_clone(void)
>>>> +{
>>>> +   static int enable = -1;
>>>> +   if (enable == -1) {
>>>> +      enable = (getenv("NIR_TEST_CLONE") == NULL) ? 0 : 1;
>>>> +   }
>>>> +   return enable == 1;
>>>> +}
>>>>  #else
>>>>  static inline void nir_validate_shader(nir_shader *shader) { (void) shader; }
>>>> +static inline bool __nir_test_clone(void) { return false; }
>>>>  #endif /* DEBUG */
>>>>
>>>> +
>>>> +#define NIR_PASS(pass, nir, ...) ({                        \
>>>> +      assert(nir_shader_is_mutable(nir));                  \
>>>> +      pass(nir, ##__VA_ARGS__);                            \
>>>> +      nir_validate_shader(nir);                            \
>>>> +      if (__nir_test_clone()) {                            \
>>>> +         nir = nir_shader_clone(ralloc_parent(nir), nir);  \
>>>> +         nir_validate_shader(nir);                         \
>>>> +      }                                                    \
>>>> +   })
>>>> +
>>>> +#define NIR_PASS_PROGRESS(pass, nir, ...) ({               \
>>>> +      assert(nir_shader_is_mutable(nir));                  \
>>>> +      bool __ret = pass(nir, ##__VA_ARGS__);               \
>>>> +      nir_validate_shader(nir);                            \
>>>> +      if (__nir_test_clone()) {                            \
>>>> +         nir = nir_shader_clone(ralloc_parent(nir), nir);  \
>>>> +         nir_validate_shader(nir);                         \
>>>> +      }                                                    \
>>>> +      __ret;                                               \
>>>> +   })
>>>> +
>>>> +
>>>>  void nir_calc_dominance_impl(nir_function_impl *impl);
>>>>  void nir_calc_dominance(nir_shader *shader);
>>>>
>>>> diff --git a/src/mesa/drivers/dri/i965/brw_nir.c b/src/mesa/drivers/dri/i965/brw_nir.c
>>>> index 8f09165..bc42fea 100644
>>>> --- a/src/mesa/drivers/dri/i965/brw_nir.c
>>>> +++ b/src/mesa/drivers/dri/i965/brw_nir.c
>>>> @@ -136,47 +136,34 @@ brw_nir_lower_outputs(nir_shader *nir, bool is_scalar)
>>>>     }
>>>>  }
>>>>
>>>> -static void
>>>> +static nir_shader *
>>>>  nir_optimize(nir_shader *nir, bool is_scalar)
>>>>  {
>>>>     bool progress;
>>>>     do {
>>>>        progress = false;
>>>> -      nir_lower_vars_to_ssa(nir);
>>>> -      nir_validate_shader(nir);
>>>>
>>>> -      if (is_scalar) {
>>>> -         nir_lower_alu_to_scalar(nir);
>>>> -         nir_validate_shader(nir);
>>>> -      }
>>>> +      NIR_PASS(nir_lower_vars_to_ssa, nir);
>>>>
>>>> -      progress |= nir_copy_prop(nir);
>>>> -      nir_validate_shader(nir);
>>>> +      if (is_scalar)
>>>> +         NIR_PASS(nir_lower_alu_to_scalar, nir);
>>>>
>>>> -      if (is_scalar) {
>>>> -         nir_lower_phis_to_scalar(nir);
>>>> -         nir_validate_shader(nir);
>>>> -      }
>>>> +      progress |= NIR_PASS_PROGRESS(nir_copy_prop, nir);
>>>> +
>>>> +      if (is_scalar)
>>>> +         NIR_PASS(nir_lower_phis_to_scalar, nir);
>>>>
>>>> -      progress |= nir_copy_prop(nir);
>>>> -      nir_validate_shader(nir);
>>>> -      progress |= nir_opt_dce(nir);
>>>> -      nir_validate_shader(nir);
>>>> -      progress |= nir_opt_cse(nir);
>>>> -      nir_validate_shader(nir);
>>>> -      progress |= nir_opt_peephole_select(nir);
>>>> -      nir_validate_shader(nir);
>>>> -      progress |= nir_opt_algebraic(nir);
>>>> -      nir_validate_shader(nir);
>>>> -      progress |= nir_opt_constant_folding(nir);
>>>> -      nir_validate_shader(nir);
>>>> -      progress |= nir_opt_dead_cf(nir);
>>>> -      nir_validate_shader(nir);
>>>> -      progress |= nir_opt_remove_phis(nir);
>>>> -      nir_validate_shader(nir);
>>>> -      progress |= nir_opt_undef(nir);
>>>> -      nir_validate_shader(nir);
>>>> +      progress |= NIR_PASS_PROGRESS(nir_copy_prop, nir);
>>>> +      progress |= NIR_PASS_PROGRESS(nir_opt_dce, nir);
>>>> +      progress |= NIR_PASS_PROGRESS(nir_opt_cse, nir);
>>>> +      progress |= NIR_PASS_PROGRESS(nir_opt_peephole_select, nir);
>>>> +      progress |= NIR_PASS_PROGRESS(nir_opt_algebraic, nir);
>>>> +      progress |= NIR_PASS_PROGRESS(nir_opt_constant_folding, nir);
>>>> +      progress |= NIR_PASS_PROGRESS(nir_opt_dead_cf, nir);
>>>> +      progress |= NIR_PASS_PROGRESS(nir_opt_remove_phis, nir);
>>>> +      progress |= NIR_PASS_PROGRESS(nir_opt_undef, nir);
>>>>     } while (progress);
>>>> +   return nir;
>>>>  }
>>>>
>>>>  nir_shader *
>>>> @@ -204,75 +191,52 @@ brw_create_nir(struct brw_context *brw,
>>>>     }
>>>>     nir_validate_shader(nir);
>>>>
>>>> -   if (stage == MESA_SHADER_GEOMETRY) {
>>>> -      nir_lower_gs_intrinsics(nir);
>>>> -      nir_validate_shader(nir);
>>>> -   }
>>>> +   if (stage == MESA_SHADER_GEOMETRY)
>>>> +      NIR_PASS(nir_lower_gs_intrinsics, nir);
>>>>
>>>> -   nir_lower_global_vars_to_local(nir);
>>>> -   nir_validate_shader(nir);
>>>> -
>>>> -   nir_lower_tex(nir, &tex_options);
>>>> -   nir_validate_shader(nir);
>>>> -
>>>> -   nir_normalize_cubemap_coords(nir);
>>>> -   nir_validate_shader(nir);
>>>> -
>>>> -   nir_split_var_copies(nir);
>>>> -   nir_validate_shader(nir);
>>>> +   NIR_PASS(nir_lower_global_vars_to_local, nir);
>>>> +   NIR_PASS(nir_lower_tex, nir, &tex_options);
>>>> +   NIR_PASS(nir_normalize_cubemap_coords, nir);
>>>> +   NIR_PASS(nir_split_var_copies, nir);
>>>>
>>>> -   nir_optimize(nir, is_scalar);
>>>> +   nir = nir_optimize(nir, is_scalar);
>>>>
>>>>     /* Lower a bunch of stuff */
>>>> -   nir_lower_var_copies(nir);
>>>> -   nir_validate_shader(nir);
>>>> +   NIR_PASS(nir_lower_var_copies, nir);
>>>>
>>>>     /* Get rid of split copies */
>>>> -   nir_optimize(nir, is_scalar);
>>>> +   nir = nir_optimize(nir, is_scalar);
>>>>
>>>>     brw_nir_lower_inputs(nir, is_scalar);
>>>>     brw_nir_lower_outputs(nir, is_scalar);
>>>>     nir_assign_var_locations(&nir->uniforms,
>>>>                              &nir->num_uniforms,
>>>>                              is_scalar ? type_size_scalar : type_size_vec4);
>>>> -   nir_lower_io(nir, nir_var_all,
>>>> +   NIR_PASS(nir_lower_io, nir, nir_var_all,
>>>>                  is_scalar ? type_size_scalar : type_size_vec4);
>>>> -   nir_validate_shader(nir);
>>>> -
>>>> -   nir_remove_dead_variables(nir);
>>>> -   nir_validate_shader(nir);
>>>>
>>>> -   if (shader_prog) {
>>>> -      nir_lower_samplers(nir, shader_prog);
>>>> -      nir_validate_shader(nir);
>>>> -   }
>>>> +   NIR_PASS(nir_remove_dead_variables, nir);
>>>>
>>>> -   nir_lower_system_values(nir);
>>>> -   nir_validate_shader(nir);
>>>> +   if (shader_prog)
>>>> +      NIR_PASS(nir_lower_samplers, nir, shader_prog);
>>>>
>>>> -   nir_lower_atomics(nir);
>>>> -   nir_validate_shader(nir);
>>>> +   NIR_PASS(nir_lower_system_values, nir);
>>>> +   NIR_PASS(nir_lower_atomics, nir);
>>>>
>>>> -   nir_optimize(nir, is_scalar);
>>>> +   nir = nir_optimize(nir, is_scalar);
>>>>
>>>>     if (brw->gen >= 6) {
>>>>        /* Try and fuse multiply-adds */
>>>> -      nir_opt_peephole_ffma(nir);
>>>> -      nir_validate_shader(nir);
>>>> +      NIR_PASS(nir_opt_peephole_ffma, nir);
>>>>     }
>>>>
>>>> -   nir_opt_algebraic_late(nir);
>>>> -   nir_validate_shader(nir);
>>>> +   NIR_PASS(nir_opt_algebraic_late, nir);
>>>>
>>>> -   nir_lower_locals_to_regs(nir);
>>>> -   nir_validate_shader(nir);
>>>> +   NIR_PASS(nir_lower_locals_to_regs, nir);
>>>>
>>>> -   nir_lower_to_source_mods(nir);
>>>> -   nir_validate_shader(nir);
>>>> -   nir_copy_prop(nir);
>>>> -   nir_validate_shader(nir);
>>>> -   nir_opt_dce(nir);
>>>> -   nir_validate_shader(nir);
>>>> +   NIR_PASS(nir_lower_to_source_mods, nir);
>>>> +   NIR_PASS(nir_copy_prop, nir);
>>>> +   NIR_PASS(nir_opt_dce, nir);
>>>>
>>>>     if (unlikely(debug_enabled)) {
>>>>        /* Re-index SSA defs so we print more sensible numbers. */
>>>> @@ -286,15 +250,11 @@ brw_create_nir(struct brw_context *brw,
>>>>        nir_print_shader(nir, stderr);
>>>>     }
>>>>
>>>> -   nir_convert_from_ssa(nir, true);
>>>> -   nir_validate_shader(nir);
>>>> +   NIR_PASS(nir_convert_from_ssa, nir, true);
>>>>
>>>>     if (!is_scalar) {
>>>> -      nir_move_vec_src_uses_to_dest(nir);
>>>> -      nir_validate_shader(nir);
>>>> -
>>>> -      nir_lower_vec_to_movs(nir);
>>>> -      nir_validate_shader(nir);
>>>> +      NIR_PASS(nir_move_vec_src_uses_to_dest, nir);
>>>> +      NIR_PASS(nir_lower_vec_to_movs, nir);
>>>>     }
>>>>
>>>>     /* This is the last pass we run before we start emitting stuff.  It
>>>> --
>>>> 2.5.0
>>>>


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