[Mesa-dev] [RFC PATCH] mesa: Add MESA_SHADER_CAPTURE_PATH for writing .shader_test files.

[Eero Tamminen]

Hi,

On 18.01.2016 17:05, Kenneth Graunke wrote:
> This writes linked shader programs to .shader_test files to
> $MESA_SHADER_CAPTURE_PATH in the format used by shader-db
> (http://cgit.freedesktop.org/mesa/shader-db).
>
> It supports both GLSL shaders and ARB programs.  All stages that
> are linked together are written in a single .shader_test file.
>
> This eliminates the need for shader-db's split-to-files.py, as Mesa
> produces the desired format directly.  It's much more reliable than
> parsing stdout/stderr, as those may contain extraneous messages, or
> simply be closed by the application and unavailable.

It also has the advantage that if IDs get recycled, it will just 
overwrite earlier file with the newer one, whereas split-to-files.py 
ignored later shader using same ID. Shaders used e.g. for game menus and 
startup are less interesting than ones used during gameplay.

If one wants startup shaders not to be overwritten, one can just kill 
the program at that point.  One could also somewhat differentiate 
shaders to different game stages (startup, menus, level 1, level 2....) 
by their file time stamps.


> We have many similar features already, but this is a bit different:
> - MESA_GLSL=dump writes to stdout, not files.

Is that still needed with MESA_SHADER_CAPTURE_PATH?

If its remaining use-case is being able to map IL & asm debug output to 
the GLSL, maybe those could also go to separate files (identified with 
common shader hash)?


> - MESA_GLSL=log writes each stage to separate files (rather than
>    all linked shaders in one file), at draw time (not link time),
>    with uniform data and state flag info.
> - Tapani's shader replacement mechanism (MESA_SHADER_DUMP_PATH and
>    MESA_SHADER_READ_PATH) also uses separate files per shader stage,
>    but allows reading in files to replace an app's shader code.


	- Eero

> v2: Dump ARB programs too, not just GLSL.
> v3: Don't dump bogus 0.shader_test file.
> v4: Add "GL_ARB_separate_shader_objects" to the [require] block.
> v5: Print "GLSL 4.00" instead of "GLSL 4.0" in the [require] block.
> v6: Don't hardcode /tmp/mesa.
>
> Signed-off-by: Kenneth Graunke <kenneth at whitecape.org>
> ---
>   src/mesa/main/arbprogram.c | 20 ++++++++++++++++++++
>   src/mesa/main/mtypes.h     |  1 -
>   src/mesa/main/shaderapi.c  | 40 ++++++++++++++++++++++++++++++++++++++++
>   src/mesa/main/shaderapi.h  |  3 +++
>   4 files changed, 63 insertions(+), 1 deletion(-)
>
> Hi Felix,
>
> Nothing nearly as cool as apitrace :)  It's just a simple patch to write
> .shader_test files for any shader programs an application asks us to compile.
> My workflow is basically:
>
>     $ mkdir /tmp/mesa
>     $ MESA_SHADER_CAPTURE_PATH=/tmp/mesa <some application>
>       (this writes a /tmp/mesa
>     $ cd ~/Projects/shader-db/shaders/...
>     $ find-duplicates /tmp/mesa/* | grep ^rm | sh
>     $ mv /tmp/mesa/* .
>     $ git add .
>     $ git commit -m 'Import shaders for ...'
>
> where find-duplicates is http://whitecape.org/stuff/find-duplicates
> To do this with Steam, you can right click on the game in the library,
> click "Properties", then "Set Launch Options", and enter:
>
>     MESA_SHADER_CAPTURE_PATH=/tmp/mesa %command%
>
>   --Ken
>
> diff --git a/src/mesa/main/arbprogram.c b/src/mesa/main/arbprogram.c
> index f474951..f78598c 100644
> --- a/src/mesa/main/arbprogram.c
> +++ b/src/mesa/main/arbprogram.c
> @@ -36,6 +36,7 @@
>   #include "main/macros.h"
>   #include "main/mtypes.h"
>   #include "main/arbprogram.h"
> +#include "main/shaderapi.h"
>   #include "program/arbprogparse.h"
>   #include "program/program.h"
>   #include "program/prog_print.h"
> @@ -373,6 +374,25 @@ _mesa_ProgramStringARB(GLenum target, GLenum format, GLsizei len,
>         }
>         fflush(stderr);
>      }
> +
> +   /* Capture vp-*.shader_test/fp-*.shader_test files. */
> +   const char *capture_path = _mesa_get_shader_capture_path();
> +   if (capture_path != NULL) {
> +      FILE *file;
> +      char filename[PATH_MAX];
> +      const char *shader_type =
> +         target == GL_FRAGMENT_PROGRAM_ARB ? "fragment" : "vertex";
> +
> +      _mesa_snprintf(filename, sizeof(filename), "%s/%cp-%u.shader_test",
> +                     capture_path, shader_type[0], base->Id);
> +      file = fopen(filename, "w");
> +      if (file) {
> +         fprintf(file,
> +                 "[require]\nGL_ARB_%s_program\n\n[%s program]\n%s\n",
> +                 shader_type, shader_type, (const char *) string);
> +         fclose(file);
> +      }
> +   }
>   }
>
>
> diff --git a/src/mesa/main/mtypes.h b/src/mesa/main/mtypes.h
> index 0992d4d..6d35e41 100644
> --- a/src/mesa/main/mtypes.h
> +++ b/src/mesa/main/mtypes.h
> @@ -2856,7 +2856,6 @@ struct gl_shader_program
>   #define GLSL_REPORT_ERRORS 0x100  /**< Print compilation errors */
>   #define GLSL_DUMP_ON_ERROR 0x200 /**< Dump shaders to stderr on compile error */
>
> -
>   /**
>    * Context state for GLSL vertex/fragment shaders.
>    * Extended to support pipeline object
> diff --git a/src/mesa/main/shaderapi.c b/src/mesa/main/shaderapi.c
> index 126786c..030d9a1 100644
> --- a/src/mesa/main/shaderapi.c
> +++ b/src/mesa/main/shaderapi.c
> @@ -96,6 +96,20 @@ _mesa_get_shader_flags(void)
>      return flags;
>   }
>
> +/**
> + * Memoized version of getenv("MESA_SHADER_CAPTURE_PATH").
> + */
> +const char *
> +_mesa_get_shader_capture_path(void)
> +{
> +   static bool read_env_var = false;
> +   static const char *path = NULL;
> +
> +   if (!read_env_var)
> +      path = getenv("MESA_SHADER_CAPTURE_PATH");
> +
> +   return path;
> +}
>
>   /**
>    * Initialize context's shader state.
> @@ -1047,6 +1061,32 @@ link_program(struct gl_context *ctx, GLuint program)
>
>      _mesa_glsl_link_shader(ctx, shProg);
>
> +   /* Capture .shader_test files. */
> +   const char *capture_path = _mesa_get_shader_capture_path();
> +   if (shProg->Name != 0 && capture_path != NULL) {
> +      FILE *file;
> +      char filename[PATH_MAX];
> +
> +      _mesa_snprintf(filename, sizeof(filename), "%s/%u.shader_test",
> +                     capture_path, shProg->Name);
> +
> +      file = fopen(filename, "w");
> +      if (file) {
> +         fprintf(file, "[require]\nGLSL >= %u.%02u\n",
> +                 shProg->Version / 100, shProg->Version % 100);
> +         if (shProg->SeparateShader)
> +            fprintf(file, "GL_ARB_separate_shader_objects\n");
> +         fprintf(file, "\n");
> +
> +         for (unsigned i = 0; i < shProg->NumShaders; i++) {
> +            fprintf(file, "[%s shader]\n%s\n",
> +                    _mesa_shader_stage_to_string(shProg->Shaders[i]->Stage),
> +                    shProg->Shaders[i]->Source);
> +         }
> +         fclose(file);
> +      }
> +   }
> +
>      if (shProg->LinkStatus == GL_FALSE &&
>          (ctx->_Shader->Flags & GLSL_REPORT_ERRORS)) {
>         _mesa_debug(ctx, "Error linking program %u:\n%s\n",
> diff --git a/src/mesa/main/shaderapi.h b/src/mesa/main/shaderapi.h
> index fba767b..2ac25d0 100644
> --- a/src/mesa/main/shaderapi.h
> +++ b/src/mesa/main/shaderapi.h
> @@ -43,6 +43,9 @@ struct gl_shader_program;
>   extern GLbitfield
>   _mesa_get_shader_flags(void);
>
> +extern const char *
> +_mesa_get_shader_capture_path(void);
> +
>   extern void
>   _mesa_copy_string(GLchar *dst, GLsizei maxLength,
>                     GLsizei *length, const GLchar *src);
>