[Mesa-dev] [PATCH 22/40] glsl: make a copy of the shader source for use with cache fallback

[Nicolai Hähnle]

On 10.02.2017 13:06, Timothy Arceri wrote:
>
>
> On 10/02/17 22:16, Nicolai Hähnle wrote:
>> On 07.02.2017 04:42, Timothy Arceri wrote:
>>> From: Timothy Arceri <timothy.arceri at collabora.com>
>>>
>>> A number of things can happen that change the shader source after it is
>>> compiled or linked.
>>>
>>> For example:
>>> - Source changed after it is first compiled
>>> - Source changed after linking
>>> - Shader detached after linking
>>>
>>> In order to be able to fallback to a full rebuild on a cache miss we
>>> make a copy of the shader source and store it in the new FallbackShaders
>>> field when linking.
>>
>> Can you explain what they're used for? It doesn't seem like this is
>> really necessary: the fallback is used by st/mesa when the TGSI
>> loading fails, but that's still during glLinkProgram().
>
> Correct. But i965 needs to fallback when it has a variant that is not
> cached, there is currently no NIR level cache.

Ah, thanks for the explanation!

Cheers,
Nicolai

>>
>> Thanks,
>> Nicolai
>>
>>> ---
>>>  src/compiler/glsl/shader_cache.cpp | 29 +++++++++++++++++++++++++++++
>>>  src/mesa/main/mtypes.h             |  2 ++
>>>  src/mesa/main/shaderobj.c          |  4 ++++
>>>  src/mesa/program/ir_to_mesa.cpp    |  8 +++++++-
>>>  4 files changed, 42 insertions(+), 1 deletion(-)
>>>
>>> diff --git a/src/compiler/glsl/shader_cache.cpp
>>> b/src/compiler/glsl/shader_cache.cpp
>>> index 583db47..729dd09 100644
>>> --- a/src/compiler/glsl/shader_cache.cpp
>>> +++ b/src/compiler/glsl/shader_cache.cpp
>>> @@ -1276,6 +1276,35 @@ shader_cache_read_program_metadata(struct
>>> gl_context *ctx,
>>>     if (!cache || prog->data->cache_fallback)
>>>        return false;
>>>
>>> +   /* Free previous fallback information */
>>> +   if (prog->data->FallbackShaders == NULL) {
>>> +      prog->data->NumFallbackShaders = 0;
>>> +      for (unsigned i = 0; i < prog->data->NumFallbackShaders; i++) {
>>> +         ralloc_free(prog->data->FallbackShaders);
>>> +         prog->data->FallbackShaders = NULL;
>>> +      }
>>> +   }
>>> +
>>> +   /* Shaders could be recompiled using different source code after
>>> linking,
>>> +    * or the shader could be detached from the program so store some
>>> +    * information about the shader to be used in case of fallback.
>>> +    */
>>> +   prog->data->NumFallbackShaders = prog->NumShaders;
>>> +   prog->data->FallbackShaders = (struct gl_shader **)
>>> +      reralloc(NULL, prog->data->FallbackShaders, struct gl_shader *,
>>> +               prog->NumShaders);
>>> +   for (unsigned i = 0; i < prog->NumShaders; i++) {
>>> +      prog->data->FallbackShaders[i] =
>>> rzalloc(prog->data->FallbackShaders,
>>> +                                               struct gl_shader);
>>> +      memcpy(prog->data->FallbackShaders[i]->sha1,
>>> prog->Shaders[i]->sha1,
>>> +             sizeof(prog->Shaders[i]->sha1));
>>> +      prog->data->FallbackShaders[i]->Stage = prog->Shaders[i]->Stage;
>>> +      prog->data->FallbackShaders[i]->Source =
>>> +         ralloc_strdup(prog->data->FallbackShaders,
>>> prog->Shaders[i]->Source);
>>> +      prog->data->FallbackShaders[i]->InfoLog =
>>> +         ralloc_strdup(prog->data->FallbackShaders, "");
>>> +   }
>>> +
>>>     for (unsigned i = 0; i < prog->NumShaders; i++) {
>>>        if (prog->Shaders[i]->Stage == MESA_SHADER_COMPUTE) {
>>>           compile_shaders(ctx, prog);
>>> diff --git a/src/mesa/main/mtypes.h b/src/mesa/main/mtypes.h
>>> index c7ca182..f65cd76 100644
>>> --- a/src/mesa/main/mtypes.h
>>> +++ b/src/mesa/main/mtypes.h
>>> @@ -2685,6 +2685,8 @@ struct gl_shader_program_data
>>>     union gl_constant_value *UniformDataSlots;
>>>
>>>     bool cache_fallback;
>>> +   GLuint NumFallbackShaders;
>>> +   struct gl_shader **FallbackShaders; /**< Shaders used for cache
>>> fallback */
>>>
>>>     /** List of all active resources after linking. */
>>>     struct gl_program_resource *ProgramResourceList;
>>> diff --git a/src/mesa/main/shaderobj.c b/src/mesa/main/shaderobj.c
>>> index b41137f..6ddccd2 100644
>>> --- a/src/mesa/main/shaderobj.c
>>> +++ b/src/mesa/main/shaderobj.c
>>> @@ -404,10 +404,14 @@ _mesa_free_shader_program_data(struct
>>> gl_context *ctx,
>>>        _mesa_reference_shader(ctx, &shProg->Shaders[i], NULL);
>>>     }
>>>     shProg->NumShaders = 0;
>>> +   shProg->data->NumFallbackShaders = 0;
>>>
>>>     free(shProg->Shaders);
>>>     shProg->Shaders = NULL;
>>>
>>> +   ralloc_free(shProg->data->FallbackShaders);
>>> +   shProg->data->FallbackShaders = NULL;
>>> +
>>>     /* Transform feedback varying vars */
>>>     for (i = 0; i < shProg->TransformFeedback.NumVarying; i++) {
>>>        free(shProg->TransformFeedback.VaryingNames[i]);
>>> diff --git a/src/mesa/program/ir_to_mesa.cpp
>>> b/src/mesa/program/ir_to_mesa.cpp
>>> index 67c9267..e286408 100644
>>> --- a/src/mesa/program/ir_to_mesa.cpp
>>> +++ b/src/mesa/program/ir_to_mesa.cpp
>>> @@ -3130,8 +3130,14 @@ _mesa_glsl_link_shader(struct gl_context *ctx,
>>> struct gl_shader_program *prog)
>>>        }
>>>     }
>>>
>>> -   if (prog->data->LinkStatus)
>>> +   if (prog->data->LinkStatus && !prog->data->cache_fallback) {
>>> +      if (prog->data->FallbackShaders) {
>>> +         prog->data->NumFallbackShaders = 0;
>>> +         ralloc_free(prog->data->FallbackShaders);
>>> +         prog->data->FallbackShaders = NULL;
>>> +      }
>>>        shader_cache_write_program_metadata(ctx, prog);
>>> +   }
>>>  }
>>>
>>>  } /* extern "C" */
>>>
>>
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