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

[Timothy Arceri]

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.

>
> 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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