[Mesa-dev] [PATCH RFC 3/3] glsl: Rework builtin_variables.cpp to reduce code duplication.

Ian Romanick idr at freedesktop.org
Thu Jul 11 16:30:41 PDT 2013


On 07/11/2013 03:52 PM, Paul Berry wrote:
> On 11 July 2013 14:09, Ian Romanick <idr at freedesktop.org
> <mailto:idr at freedesktop.org>> wrote:
>
>     I like these changes a lot.  I have a few comments below.
>
>
>     On 07/08/2013 10:40 AM, Paul Berry wrote:
>
>         Previously, we had a separate function for setting up the built-in
>         variables for each combination of shader stage and GLSL version
>         (e.g. generate_110_vs_variables to generate the built-in
>         variables for
>         GLSL 1.10 vertex shaders).  The functions called each other in
>         ad-hoc
>         ways, leading to unexpected inconsistencies (for example,
>         generate_120_fs_variables was called for GLSL versions 1.20 and
>         above,
>         but generate_130_fs_variables was called only for GLSL version
>         1.30).
>         In addition, it led to a lot of code duplication, since many
>         varyings
>         had to be duplicated in both the FS and VS code paths.  With the
>         advent of geometry shaders (and later, tessellation control and
>         tessellation evaluation shaders), this code duplication was going to
>         get a lot worse.
>
>         So this patch reworks things so that instead of having a separate
>         function for each shader type and GLSL version, we have a
>         function for
>         constants, one for uniforms, one for varyings, and one for the
>         special
>         variables that are specific to each shader type.
>
>         In addition, we use a class, builtin_variable_generator, to keep
>         track
>         of the instruction exec_list, the GLSL parse state, commonly-used
>         types, and a few other variables, so that we don't have to pass them
>         around as function arguments.  This makes the code a lot more
>         compact.
>
>         Where it was feasible to do so without introducing compilation
>         errors,
>         I've also gone ahead and introduced the variables needed for
>         {ARB,EXT}_geometry_shader4 style geometry shaders.  This patch takes
>         care of everything except the GS variable gl_VerticesIn, the FS
>         variable gl_PrimitiveID, and GLSL 1.50 style geometry shader inputs
>         (using the gl_in interface block).  Those remaining features will be
>         added later.
>
>         I've also made a slight nomenclature change: previously we used the
>         word "deprecated" to refer to variables which are marked in GLSL
>         1.40
>         as requiring the ARB_compatibility extension, and are marked in GLSL
>         1.50 onward as requiring the compatibilty profile.  This was
>         misleading, since not all deprecated variables require the
>         compatibility profile (for example gl_FragData and gl_FragColor,
>         which
>         have been deprecated since GLSL 1.30, but do not require the
>         compatibility profile until GLSL 4.20).  We now consistently use the
>         word "compatibility" to refer to these variables.
>
>
>     This may be evidence of one or more bugs in our implementation.  In
>     a forward-compatible 3.0+ context, *all* deprecated variables are
>     removed.  In a 3.1 context without GL_ARB_compatibiliyt, some
>     deprecated variables are removed.  Which, I think, I mostly what
>     you're saying.
>
>
> Not exactly.  My reading of the specs is that in a forward-compatible
> 3.0+ context, all deprecated variables are removed *except*
> gl_FragColor, gl_FragData, and gl_MaxVaryingFloats.  These three
> variables are marked as "deprecated" in GLSL 1.30 through 4.10, but the
> text that says that they are only available in the compatibility profile
> does not appear until GLSL 4.20.  This looks like a deliberate change
> rather than a correction of an oversight, since GLSL 4.20 lists
> gl_FragColor and gl_FragData in its summary of changes since 4.10 as
> "Move these previously deprecated features to be only in the
> compatibility profile".

I think we're miscommunicating, so I'll try to clarify. 
Forward-compatible is a special kind of context that the user has to 
opt-in.  This is different than a core profile or 3.1 without 
GL_ARB_compatibility.  In a forward-compatible context every deprecated 
feature is removed, even if no future spec removes it.

So, this means there's really three kinds of context: compatibility 
profile, core profile, and forward-compatible core profile.

Section 1.6 (Deprecation) of the 1.30, 1.40, and 1.50 GLSL specs say:

     "The OpenGL API has a forward compatibility mode that will disallow
     use of deprecated features. If compiling in a mode where use of
     deprecated features is disallowed, their use causes compile time
     errors."

That gl_FragColor and gl_FragData weren't removed in 1.40 (with 3.1 
without GL_ARB_compatibility) or 1.50 (with a 3.2 core profile) doesn't 
matter for this case.  If the user makes a 3.{0,1,2,3} 
forward-compatible context, they are gone because they are deprecated.

>       Do we handle the forward-compatible context case correctly?
>
>
> If you mean to ask: "do we do the right thing if the user attempts to
> compile a pre-GLSL-1.40 shader in a forward-compatible context", then I
> believe the answer is no.  We go ahead and enable the compatibility-only
> variables in that case.  With my rewrite, that bug should be trivial to
> fix.  I'll make a follow-up patch to fix it.  Unfortunately, without my
> rewrite, it would be a pain to fix.

With the above clarification, what I'm asking is if the user creates a 
3.1 forward-compatible context, does the following shader fail to compile?

#version 140
void main() { gl_FragColor = vec4(0); }

>         This patch doesn't introduce any functional changes (since geometry
>         shaders haven't been enabled yet).
>         ---
>            src/glsl/builtin_variables.cpp | 1124
>         +++++++++++++-----------------__----------
>            1 file changed, 363 insertions(+), 761 deletions(-)
>
>         diff --git a/src/glsl/builtin_variables.__cpp
>         b/src/glsl/builtin_variables.__cpp
>         index eccd15a..0c74200 100644
>         --- a/src/glsl/builtin_variables.__cpp
>         +++ b/src/glsl/builtin_variables.__cpp
>         @@ -30,116 +30,6 @@
>            #include "program/prog_statevars.h"
>            #include "program/prog_instruction.h"
>
>         -static void generate_ARB_draw_buffers___variables(exec_list *,
>         -                                               struct
>         _mesa_glsl_parse_state *,
>         -                                               bool,
>         _mesa_glsl_parser_targets);
>         -
>         -static void
>         -generate_ARB_draw_instanced___variables(exec_list *,
>         -                                      struct
>         _mesa_glsl_parse_state *,
>         -                                      bool,
>         _mesa_glsl_parser_targets);
>         -
>         -static void
>         -generate_AMD_vertex_shader___layer_variables(exec_list
>         *instructions,
>         -                                           struct
>         _mesa_glsl_parse_state *state,
>         -                                           bool warn,
>         -
>         _mesa_glsl_parser_targets target);
>         -
>         -struct builtin_variable {
>         -   enum ir_variable_mode mode;
>         -   int slot;
>         -   const char *type;
>         -   const char *name;
>         -};
>         -
>         -static const builtin_variable builtin_core_vs_variables[] = {
>         -   { ir_var_shader_out, VARYING_SLOT_POS,  "vec4",
>           "gl_Position" },
>         -   { ir_var_shader_out, VARYING_SLOT_PSIZ, "float",
>         "gl_PointSize" },
>         -};
>         -
>         -static const builtin_variable builtin_core_fs_variables[] = {
>         -   { ir_var_shader_in,  VARYING_SLOT_POS,  "vec4",
>           "gl_FragCoord" },
>         -   { ir_var_shader_in,  VARYING_SLOT_FACE, "bool",
>           "gl_FrontFacing" },
>         -   { ir_var_shader_out, FRAG_RESULT_COLOR, "vec4",
>           "gl_FragColor" },
>         -};
>         -
>         -static const builtin_variable builtin_100ES_fs_variables[] = {
>         -   { ir_var_shader_in,  VARYING_SLOT_PNTC,   "vec2",
>         "gl_PointCoord" },
>         -};
>         -
>         -static const builtin_variable builtin_300ES_vs_variables[] = {
>         -   { ir_var_system_value,  SYSTEM_VALUE_VERTEX_ID, "int",
>         "gl_VertexID" },
>         -};
>         -
>         -static const builtin_variable builtin_300ES_fs_variables[] = {
>         -   { ir_var_shader_in,  VARYING_SLOT_POS,  "vec4",
>           "gl_FragCoord" },
>         -   { ir_var_shader_in,  VARYING_SLOT_FACE, "bool",
>           "gl_FrontFacing" },
>         -   { ir_var_shader_out, FRAG_RESULT_DEPTH, "float",
>         "gl_FragDepth" },
>         -   { ir_var_shader_in,  VARYING_SLOT_PNTC, "vec2",
>           "gl_PointCoord" },
>         -};
>         -
>         -static const builtin_variable builtin_110_fs_variables[] = {
>         -   { ir_var_shader_out, FRAG_RESULT_DEPTH, "float",
>         "gl_FragDepth" },
>         -};
>         -
>         -static const builtin_variable
>         builtin_110_deprecated_fs___variables[] = {
>         -   { ir_var_shader_in,  VARYING_SLOT_COL0,  "vec4",  "gl_Color" },
>         -   { ir_var_shader_in,  VARYING_SLOT_COL1,  "vec4",
>           "gl_SecondaryColor" },
>         -   { ir_var_shader_in,  VARYING_SLOT_FOGC,  "float",
>         "gl_FogFragCoord" },
>         -};
>         -
>         -static const builtin_variable
>         builtin_110_deprecated_vs___variables[] = {
>         -   { ir_var_shader_in,  VERT_ATTRIB_POS,         "vec4",
>           "gl_Vertex" },
>         -   { ir_var_shader_in,  VERT_ATTRIB_NORMAL,      "vec3",
>           "gl_Normal" },
>         -   { ir_var_shader_in,  VERT_ATTRIB_COLOR0,      "vec4",
>           "gl_Color" },
>         -   { ir_var_shader_in,  VERT_ATTRIB_COLOR1,      "vec4",
>           "gl_SecondaryColor" },
>         -   { ir_var_shader_in,  VERT_ATTRIB_TEX0,        "vec4",
>           "gl_MultiTexCoord0" },
>         -   { ir_var_shader_in,  VERT_ATTRIB_TEX1,        "vec4",
>           "gl_MultiTexCoord1" },
>         -   { ir_var_shader_in,  VERT_ATTRIB_TEX2,        "vec4",
>           "gl_MultiTexCoord2" },
>         -   { ir_var_shader_in,  VERT_ATTRIB_TEX3,        "vec4",
>           "gl_MultiTexCoord3" },
>         -   { ir_var_shader_in,  VERT_ATTRIB_TEX4,        "vec4",
>           "gl_MultiTexCoord4" },
>         -   { ir_var_shader_in,  VERT_ATTRIB_TEX5,        "vec4",
>           "gl_MultiTexCoord5" },
>         -   { ir_var_shader_in,  VERT_ATTRIB_TEX6,        "vec4",
>           "gl_MultiTexCoord6" },
>         -   { ir_var_shader_in,  VERT_ATTRIB_TEX7,        "vec4",
>           "gl_MultiTexCoord7" },
>         -   { ir_var_shader_in,  VERT_ATTRIB_FOG,         "float",
>         "gl_FogCoord" },
>         -   { ir_var_shader_out, VARYING_SLOT_CLIP_VERTEX, "vec4",
>           "gl_ClipVertex" },
>         -   { ir_var_shader_out, VARYING_SLOT_COL0,        "vec4",
>           "gl_FrontColor" },
>         -   { ir_var_shader_out, VARYING_SLOT_BFC0,        "vec4",
>           "gl_BackColor" },
>         -   { ir_var_shader_out, VARYING_SLOT_COL1,        "vec4",
>           "gl_FrontSecondaryColor" },
>         -   { ir_var_shader_out, VARYING_SLOT_BFC1,        "vec4",
>           "gl_BackSecondaryColor" },
>         -   { ir_var_shader_out, VARYING_SLOT_FOGC,        "float",
>         "gl_FogFragCoord" },
>         -};
>         -
>         -static const builtin_variable builtin_120_fs_variables[] = {
>         -   { ir_var_shader_in,  VARYING_SLOT_PNTC,   "vec2",
>         "gl_PointCoord" },
>         -};
>         -
>         -static const builtin_variable builtin_130_vs_variables[] = {
>         -   { ir_var_system_value,  SYSTEM_VALUE_VERTEX_ID, "int",
>         "gl_VertexID" },
>         -};
>         -
>         -static const builtin_variable
>         builtin_110_deprecated___uniforms[] = {
>         -   { ir_var_uniform, -1, "mat4", "gl_ModelViewMatrix" },
>         -   { ir_var_uniform, -1, "mat4", "gl_ProjectionMatrix" },
>         -   { ir_var_uniform, -1, "mat4", "gl_ModelViewProjectionMatrix" },
>         -   { ir_var_uniform, -1, "mat3", "gl_NormalMatrix" },
>         -   { ir_var_uniform, -1, "mat4", "gl_ModelViewMatrixInverse" },
>         -   { ir_var_uniform, -1, "mat4", "gl_ProjectionMatrixInverse" },
>         -   { ir_var_uniform, -1, "mat4",
>         "gl___ModelViewProjectionMatrixInver__se" },
>         -   { ir_var_uniform, -1, "mat4", "gl_ModelViewMatrixTranspose" },
>         -   { ir_var_uniform, -1, "mat4", "gl_ProjectionMatrixTranspose" },
>         -   { ir_var_uniform, -1, "mat4",
>         "gl___ModelViewProjectionMatrixTrans__pose" },
>         -   { ir_var_uniform, -1, "mat4",
>         "gl___ModelViewMatrixInverseTranspos__e" },
>         -   { ir_var_uniform, -1, "mat4",
>         "gl___ProjectionMatrixInverseTranspo__se" },
>         -   { ir_var_uniform, -1, "mat4",
>         "gl___ModelViewProjectionMatrixInver__seTranspose" },
>         -   { ir_var_uniform, -1, "float", "gl_NormalScale" },
>         -   { ir_var_uniform, -1, "gl_LightModelParameters",
>         "gl_LightModel"},
>         -
>         -   /* Mesa-internal ATI_envmap_bumpmap state. */
>         -   { ir_var_uniform, -1, "vec2", "gl_BumpRotMatrix0MESA"},
>         -   { ir_var_uniform, -1, "vec2", "gl_BumpRotMatrix1MESA"},
>         -   { ir_var_uniform, -1, "vec4", "gl_FogParamsOptimizedMESA"},
>         -};
>
>            static struct gl_builtin_uniform_element
>         gl_DepthRange_elements[] = {
>               {"near", {STATE_DEPTH_RANGE, 0, 0}, SWIZZLE_XXXX},
>         @@ -400,10 +290,88 @@ static const struct
>         gl_builtin_uniform_desc _mesa_builtin_uniform_desc[] = {
>               {NULL, NULL, 0}
>            };
>
>         -static ir_variable *
>         -add_variable(exec_list *instructions, glsl_symbol_table *symtab,
>         -            const char *name, const glsl_type *type,
>         -            enum ir_variable_mode mode, int slot)
>         +
>         +namespace {
>         +
>         +class builtin_variable_generator
>         +{
>         +public:
>         +   builtin_variable_generator(__exec_list *instructions,
>         +                              struct _mesa_glsl_parse_state
>         *state);
>         +   void generate_constants();
>         +   void generate_uniforms();
>         +   void generate_vs_special_vars();
>         +   void generate_gs_special_vars();
>         +   void generate_fs_special_vars();
>         +   void generate_varyings();
>         +
>         +private:
>         +   const glsl_type *array(const glsl_type *base, unsigned elements)
>         +   {
>         +      return glsl_type::get_array_instance(__base, elements);
>         +   }
>         +   const glsl_type *typ(const char *name)
>         +   {
>         +      return symtab->get_type(name);
>         +   }
>
>
>     Around declarations that are definitions, we generally put a blank line.
>
>
> Ok, I'll fix this.
>
>
>         +   ir_variable *add_variable(const char *name, const glsl_type
>         *type,
>         +                             enum ir_variable_mode mode, int slot);
>         +   ir_variable *add_uniform(const glsl_type *type, const char
>         *name);
>         +   ir_variable *add_const(const char *name, int value);
>         +   ir_variable *add_input(int slot, const glsl_type *type,
>         const char *name)
>         +   {
>         +      return add_variable(name, type, ir_var_shader_in, slot);
>         +   }
>         +   ir_variable *add_output(int slot, const glsl_type *type,
>         const char *name)
>         +   {
>         +      return add_variable(name, type, ir_var_shader_out, slot);
>         +   }
>         +   ir_variable *add_system_value(int slot, const glsl_type *type,
>         +                                 const char *name)
>         +   {
>         +      return add_variable(name, type, ir_var_system_value, slot);
>         +   }
>         +   void add_varying(int slot, const glsl_type *type, const char
>         *name,
>         +                    const char *name_as_gs_input);
>         +
>         +   exec_list * const instructions;
>         +   struct _mesa_glsl_parse_state * const state;
>         +   glsl_symbol_table * const symtab;
>         +
>         +   /**
>         +    * True if compatibility-profile-only variables should be
>         included.  (In
>         +    * desktop GL, these are always included when the GLSL
>         version is 1.30 and
>         +    * or below).
>         +    */
>         +   const bool compatibility;
>         +
>         +   const glsl_type * const bool_t;
>         +   const glsl_type * const int_t;
>         +   const glsl_type * const float_t;
>         +   const glsl_type * const vec2_t;
>         +   const glsl_type * const vec3_t;
>         +   const glsl_type * const vec4_t;
>         +   const glsl_type * const mat3_t;
>         +   const glsl_type * const mat4_t;
>
>
>     I'm not super in love with this.  It saves a bit of typing, but it
>     adds yet another way to get at the types.  I don't like having to
>     think, "How do I get at the types in *this* source file?"
>
>     If I'm the only objector, I don't think my opposition is strong
>     enough to make you change it.
>
>
> I don't have a strong opinion either, although for the record I wasn't
> trying to save typing so much as I was trying to aid in readibility by
> keeping things on one 80-column line.  Without these definitions, 18 of
> the variable declarations that follow would have to get split to
> multiple lines, e.g.

That makes sense.  I remember you mentioning that before you sent the 
patches out.

>           ADD_VARYING(VARYING_SLOT_CLIP_VERTEX, vec4_t, "gl_ClipVertex");
>
> would become
>
>           ADD_VARYING(VARYING_SLOT_CLIP_VERTEX, glsl_type::vec4_type,
>                       "gl_ClipVertex");
>
> I honestly could go either way.

Well, if nobody else speaks up, just leave it as is.

>         +};
>         +
>         +
>         +builtin_variable_generator::__builtin_variable_generator(
>         +   exec_list *instructions, struct _mesa_glsl_parse_state *state)
>         +   : instructions(instructions), state(state),
>         symtab(state->symbols),
>         +     compatibility(!state->is___version(140, 100)),
>         +     bool_t(glsl_type::bool_type), int_t(glsl_type::int_type),
>         +     float_t(glsl_type::float_type)__,
>         vec2_t(glsl_type::vec2_type),
>         +     vec3_t(glsl_type::vec3_type), vec4_t(glsl_type::vec4_type),
>         +     mat3_t(glsl_type::mat3_type), mat4_t(glsl_type::mat4_type)
>         +{
>         +}
>         +
>         +
>         +ir_variable *
>         +builtin_variable_generator::__add_variable(const char *name,
>         +                                         const glsl_type *type,
>         +                                         enum ir_variable_mode
>         mode, int slot)
>            {
>               ir_variable *var = new(symtab) ir_variable(type, name, mode);
>
>         @@ -438,12 +406,12 @@ add_variable(exec_list *instructions,
>         glsl_symbol_table *symtab,
>               return var;
>            }
>
>         -static ir_variable *
>         -add_uniform(exec_list *instructions, glsl_symbol_table *symtab,
>         -           const char *name, const glsl_type *type)
>         +
>         +ir_variable *
>         +builtin_variable_generator::__add_uniform(const glsl_type *type,
>         +                                        const char *name)
>            {
>         -   ir_variable *const uni =
>         -      add_variable(instructions, symtab, name, type,
>         ir_var_uniform, -1);
>         +   ir_variable *const uni = add_variable(name, type,
>         ir_var_uniform, -1);
>
>               unsigned i;
>               for (i = 0; _mesa_builtin_uniform_desc[i].__name != NULL;
>         i++) {
>         @@ -486,31 +454,11 @@ add_uniform(exec_list *instructions,
>         glsl_symbol_table *symtab,
>               return uni;
>            }
>
>         -static void
>         -add_builtin_variable(exec___list *instructions,
>         glsl_symbol_table *symtab,
>         -                    const builtin_variable *proto)
>         -{
>         -   /* Create a new variable declaration from the description
>         supplied by
>         -    * the caller.
>         -    */
>         -   const glsl_type *const type = symtab->get_type(proto->type);
>         -
>         -   assert(type != NULL);
>
>         -   if (proto->mode == ir_var_uniform) {
>         -      add_uniform(instructions, symtab, proto->name, type);
>         -   } else {
>         -      add_variable(instructions, symtab, proto->name, type,
>         proto->mode,
>         -                  proto->slot);
>         -   }
>         -}
>         -
>         -static ir_variable *
>         -add_builtin_constant(exec___list *instructions,
>         glsl_symbol_table *symtab,
>         -                    const char *name, int value)
>         +ir_variable *
>         +builtin_variable_generator::__add_const(const char *name, int
>         value)
>            {
>         -   ir_variable *const var = add_variable(instructions, symtab,
>         -                                        name, glsl_type::int_type,
>         +   ir_variable *const var = add_variable(name, glsl_type::int_type,
>                                                   ir_var_auto, -1);
>               var->constant_value = new(var) ir_constant(value);
>               var->constant_initializer = new(var) ir_constant(value);
>         @@ -518,701 +466,355 @@ add_builtin_constant(exec_list
>         *instructions, glsl_symbol_table *symtab,
>               return var;
>            }
>
>         -/**
>         - * Uniforms that are common to all GLSL ES implementations.
>         - *
>         - * Several constants in GLSL ES have different names than
>         normal desktop GLSL.
>         - * Therefore, this function should only be called on the ES path.
>         - */
>         -static void
>         -generate_common_ES_uniforms(__exec_list *instructions,
>         -                            struct _mesa_glsl_parse_state *state)
>         -{
>         -   glsl_symbol_table *const symtab = state->symbols;
>         -
>         -   add_builtin_constant(__instructions, symtab,
>         "gl_MaxVertexAttribs",
>         -                       state->Const.MaxVertexAttribs)__;
>         -   add_builtin_constant(__instructions, symtab,
>         "gl_MaxVertexUniformVectors",
>         -
>         state->Const.__MaxVertexUniformComponents / 4);
>         -   add_builtin_constant(__instructions, symtab,
>         "gl___MaxVertexTextureImageUnits",
>         -                       state->Const.__MaxVertexTextureImageUnits);
>         -   add_builtin_constant(__instructions, symtab,
>         "gl___MaxCombinedTextureImageUnits",
>         -
>         state->Const.__MaxCombinedTextureImageUnits);
>         -   add_builtin_constant(__instructions, symtab,
>         "gl_MaxTextureImageUnits",
>         -                       state->Const.__MaxTextureImageUnits);
>         -   add_builtin_constant(__instructions, symtab,
>         "gl_MaxFragmentUniformVectors"__,
>         -
>         state->Const.__MaxFragmentUniformComponents / 4);
>         -
>         -   add_uniform(instructions, symtab, "gl_DepthRange",
>         -
>           state->symbols->get_type("gl___DepthRangeParameters"));
>         -}
>         -
>         -static void
>         -generate_100ES_uniforms(exec___list *instructions,
>         -                    struct _mesa_glsl_parse_state *state)
>         -{
>         -   generate_common_ES_uniforms(__instructions, state);
>         -
>         -   glsl_symbol_table *const symtab = state->symbols;
>         -
>         -   add_builtin_constant(__instructions, symtab,
>         "gl_MaxVaryingVectors",
>         -                       state->Const.MaxVaryingFloats / 4);
>         -}
>
>         -static void
>         -generate_300ES_uniforms(exec___list *instructions,
>         -                        struct _mesa_glsl_parse_state *state)
>         +void
>         +builtin_variable_generator::__generate_constants()
>            {
>         -   generate_common_ES_uniforms(__instructions, state);
>         -
>         -   glsl_symbol_table *const symtab = state->symbols;
>         -
>         -   add_builtin_constant(__instructions, symtab,
>         "gl_MaxVertexOutputVectors",
>         -                       state->Const.MaxVaryingFloats / 4);
>         -   add_builtin_constant(__instructions, symtab,
>         "gl_MaxFragmentInputVectors",
>         -                       state->Const.MaxVaryingFloats / 4);
>         -   add_builtin_constant(__instructions, symtab,
>         "gl_MinProgramTexelOffset",
>         -                        state->Const.__MinProgramTexelOffset);
>         -   add_builtin_constant(__instructions, symtab,
>         "gl_MaxProgramTexelOffset",
>         -                        state->Const.__MaxProgramTexelOffset);
>         -}
>         +   add_const("gl___MaxVertexAttribs",
>         state->Const.MaxVertexAttribs)__;
>         +   add_const("gl___MaxVertexTextureImageUnits",
>         +             state->Const.__MaxVertexTextureImageUnits);
>         +   add_const("gl___MaxCombinedTextureImageUnits",
>         +             state->Const.__MaxCombinedTextureImageUnits);
>         +   add_const("gl___MaxTextureImageUnits",
>         state->Const.__MaxTextureImageUnits);
>         +   add_const("gl_MaxDrawBuffers", state->Const.MaxDrawBuffers);
>         +
>         +   /* Max uniforms/varyings: GLSL ES counts these in units of
>         vectors; desktop
>         +    * GL counts them in units of "components" or "floats".
>         +    */
>         +   if (state->es_shader) {
>         +      add_const("gl___MaxVertexUniformVectors",
>         +                state->Const.__MaxVertexUniformComponents / 4);
>         +      add_const("gl___MaxFragmentUniformVectors",
>         +                state->Const.__MaxFragmentUniformComponents / 4);
>
>         -static void
>         -generate_110_uniforms(exec___list *instructions,
>         -                     struct _mesa_glsl_parse_state *state,
>         -                     bool add_deprecated)
>         -{
>         -   glsl_symbol_table *const symtab = state->symbols;
>         -
>         -   if (add_deprecated) {
>         -      for (unsigned i = 0
>         -             ; i < Elements(builtin_110___deprecated_uniforms)
>         -             ; i++) {
>         -        add_builtin_variable(__instructions, symtab,
>         -                             &
>         builtin_110_deprecated___uniforms[i]);
>         +      /* In GLSL ES 3.00, gl_MaxVaryingVectors was split out to
>         separate
>         +       * vertex and fragment shader constants.
>         +       */
>         +      if (state->is_version(0, 300)) {
>         +         add_const("gl___MaxVertexOutputVectors",
>         +                   state->Const.MaxVaryingFloats / 4);
>         +         add_const("gl___MaxFragmentInputVectors",
>         +                   state->Const.MaxVaryingFloats / 4);
>         +      } else {
>         +         add_const("gl___MaxVaryingVectors",
>         state->Const.MaxVaryingFloats / 4);
>                  }
>         -   }
>         -
>         -   if (add_deprecated) {
>         -      add_builtin_constant(__instructions, symtab, "gl_MaxLights",
>         -                          state->Const.MaxLights);
>         -      add_builtin_constant(__instructions, symtab,
>         "gl_MaxClipPlanes",
>         -                          state->Const.MaxClipPlanes);
>         -      add_builtin_constant(__instructions, symtab,
>         "gl_MaxTextureUnits",
>         -                          state->Const.MaxTextureUnits);
>         -      add_builtin_constant(__instructions, symtab,
>         "gl_MaxTextureCoords",
>         -                          state->Const.MaxTextureCoords)__;
>         -   }
>         -   add_builtin_constant(__instructions, symtab,
>         "gl_MaxVertexAttribs",
>         -                       state->Const.MaxVertexAttribs)__;
>         -   add_builtin_constant(__instructions, symtab,
>         "gl___MaxVertexUniformComponents",
>         -                       state->Const.__MaxVertexUniformComponents);
>         -   add_builtin_constant(__instructions, symtab,
>         "gl_MaxVaryingFloats",
>         -                       state->Const.MaxVaryingFloats)__;
>         -   add_builtin_constant(__instructions, symtab,
>         "gl___MaxVertexTextureImageUnits",
>         -                       state->Const.__MaxVertexTextureImageUnits);
>         -   add_builtin_constant(__instructions, symtab,
>         "gl___MaxCombinedTextureImageUnits",
>         -
>         state->Const.__MaxCombinedTextureImageUnits);
>         -   add_builtin_constant(__instructions, symtab,
>         "gl_MaxTextureImageUnits",
>         -                       state->Const.__MaxTextureImageUnits);
>         -   add_builtin_constant(__instructions, symtab,
>         "gl___MaxFragmentUniformComponents",
>         -
>         state->Const.__MaxFragmentUniformComponents);
>         -
>         -   if (add_deprecated) {
>         -      const glsl_type *const mat4_array_type =
>         -        glsl_type::get_array_instance(__glsl_type::mat4_type,
>         -
>           state->Const.MaxTextureCoords)__;
>         -
>         -      add_uniform(instructions, symtab, "gl_TextureMatrix",
>         mat4_array_type);
>         -      add_uniform(instructions, symtab,
>         "gl_TextureMatrixInverse", mat4_array_type);
>         -      add_uniform(instructions, symtab,
>         "gl_TextureMatrixTranspose", mat4_array_type);
>         -      add_uniform(instructions, symtab,
>         "gl___TextureMatrixInverseTranspose"__, mat4_array_type);
>         -   }
>         -
>         -   add_uniform(instructions, symtab, "gl_DepthRange",
>         -               symtab->get_type("gl___DepthRangeParameters"));
>         -
>         -   if (add_deprecated) {
>         -      add_uniform(instructions, symtab, "gl_ClipPlane",
>         -
>         glsl_type::get_array_instance(__glsl_type::vec4_type,
>         -
>         state->Const.MaxClipPlanes));
>         -      add_uniform(instructions, symtab, "gl_Point",
>         -                 symtab->get_type("gl___PointParameters"));
>         -
>         -      const glsl_type *const material_parameters_type =
>         -        symtab->get_type("gl___MaterialParameters");
>         -      add_uniform(instructions, symtab, "gl_FrontMaterial",
>         material_parameters_type);
>         -      add_uniform(instructions, symtab, "gl_BackMaterial",
>         material_parameters_type);
>         -
>         -      const glsl_type *const light_source_array_type =
>         -
>           glsl_type::get_array_instance(__symtab->get_type("gl___LightSourceParameters"), state->Const.MaxLights);
>         -
>         -      add_uniform(instructions, symtab, "gl_LightSource",
>         light_source_array_type);
>         -
>         -      const glsl_type *const light_model_products_type =
>         -        symtab->get_type("gl___LightModelProducts");
>         -      add_uniform(instructions, symtab,
>         "gl_FrontLightModelProduct",
>         -                 light_model_products_type);
>         -      add_uniform(instructions, symtab, "gl_BackLightModelProduct",
>         -                 light_model_products_type);
>         -
>         -      const glsl_type *const light_products_type =
>         -
>           glsl_type::get_array_instance(__symtab->get_type("gl___LightProducts"),
>         -                                      state->Const.MaxLights);
>         -      add_uniform(instructions, symtab, "gl_FrontLightProduct",
>         light_products_type);
>         -      add_uniform(instructions, symtab, "gl_BackLightProduct",
>         light_products_type);
>         -
>         -      add_uniform(instructions, symtab, "gl_TextureEnvColor",
>         -
>         glsl_type::get_array_instance(__glsl_type::vec4_type,
>         -
>         state->Const.MaxTextureUnits))__;
>         -
>         -      const glsl_type *const texcoords_vec4 =
>         -        glsl_type::get_array_instance(__glsl_type::vec4_type,
>         -
>           state->Const.MaxTextureCoords)__;
>         -      add_uniform(instructions, symtab, "gl_EyePlaneS",
>         texcoords_vec4);
>         -      add_uniform(instructions, symtab, "gl_EyePlaneT",
>         texcoords_vec4);
>         -      add_uniform(instructions, symtab, "gl_EyePlaneR",
>         texcoords_vec4);
>         -      add_uniform(instructions, symtab, "gl_EyePlaneQ",
>         texcoords_vec4);
>         -      add_uniform(instructions, symtab, "gl_ObjectPlaneS",
>         texcoords_vec4);
>         -      add_uniform(instructions, symtab, "gl_ObjectPlaneT",
>         texcoords_vec4);
>         -      add_uniform(instructions, symtab, "gl_ObjectPlaneR",
>         texcoords_vec4);
>         -      add_uniform(instructions, symtab, "gl_ObjectPlaneQ",
>         texcoords_vec4);
>         -
>         -      add_uniform(instructions, symtab, "gl_Fog",
>         -                 symtab->get_type("gl___FogParameters"));
>         -   }
>         -
>         -   /* Mesa-internal current attrib state */
>         -   const glsl_type *const vert_attribs =
>         -      glsl_type::get_array_instance(__glsl_type::vec4_type,
>         VERT_ATTRIB_MAX);
>         -   add_uniform(instructions, symtab,
>         "gl_CurrentAttribVertMESA", vert_attribs);
>         -   const glsl_type *const frag_attribs =
>         -      glsl_type::get_array_instance(__glsl_type::vec4_type,
>         VARYING_SLOT_MAX);
>         -   add_uniform(instructions, symtab,
>         "gl_CurrentAttribFragMESA", frag_attribs);
>         -}
>         -
>         -/* This function should only be called for ES, not desktop GL. */
>         -static void
>         -generate_100ES_vs_variables(__exec_list *instructions,
>         -                         struct _mesa_glsl_parse_state *state)
>         -{
>         -   for (unsigned i = 0; i <
>         Elements(builtin_core_vs___variables); i++) {
>         -      add_builtin_variable(__instructions, state->symbols,
>         -                          & builtin_core_vs_variables[i]);
>         -   }
>         -
>         -   generate_100ES_uniforms(__instructions, state);
>         +   } else {
>         +      add_const("gl___MaxVertexUniformComponents",
>         +                state->Const.__MaxVertexUniformComponents);
>
>         -   generate_ARB_draw_buffers___variables(instructions, state,
>         false,
>         -                                      vertex_shader);
>         -}
>         +      /* Note: gl_MaxVaryingFloats was deprecated in GLSL
>         1.30+, but not
>         +       * removed
>         +       */
>         +      add_const("gl___MaxVaryingFloats",
>         state->Const.MaxVaryingFloats)__;
>
>         -static void
>         -generate_300ES_vs_variables(__exec_list *instructions,
>         -                            struct _mesa_glsl_parse_state *state)
>         -{
>         -   for (unsigned i = 0; i <
>         Elements(builtin_core_vs___variables); i++) {
>         -      add_builtin_variable(__instructions, state->symbols,
>         -                          & builtin_core_vs_variables[i]);
>         +      add_const("gl___MaxFragmentUniformComponents",
>         +                state->Const.__MaxFragmentUniformComponents);
>               }
>
>         -   for (unsigned i = 0; i <
>         Elements(builtin_300ES_vs___variables); i++) {
>         -      add_builtin_variable(__instructions, state->symbols,
>         -                          & builtin_300ES_vs_variables[i])__;
>         +   /* Texel offsets were introduced in
>         ARB_shading_language_420pack (which
>         +    * requires desktop GLSL version 130), and adopted into
>         desktop GLSL
>         +    * version 4.20 and GLSL ES version 3.00.
>         +    */
>         +   if ((state->is_version(130, 0) &&
>         +        state->ARB_shading_language___420pack_enable) ||
>         +      state->is_version(420, 300)) {
>         +      add_const("gl___MinProgramTexelOffset",
>         +                state->Const.__MinProgramTexelOffset);
>         +      add_const("gl___MaxProgramTexelOffset",
>         +                state->Const.__MaxProgramTexelOffset);
>               }
>
>         -   generate_300ES_uniforms(__instructions, state);
>         -
>         -   generate_ARB_draw_buffers___variables(instructions, state,
>         false,
>         -                                      vertex_shader);
>         -}
>         -
>         -
>         -static void
>         -generate_110_vs_variables(__exec_list *instructions,
>         -                         struct _mesa_glsl_parse_state *state,
>         -                         bool add_deprecated)
>         -{
>         -   for (unsigned i = 0; i <
>         Elements(builtin_core_vs___variables); i++) {
>         -      add_builtin_variable(__instructions, state->symbols,
>         -                          & builtin_core_vs_variables[i]);
>         +   if (state->is_version(130, 0)) {
>         +      add_const("gl___MaxClipDistances",
>         state->Const.MaxClipPlanes);
>         +      add_const("gl___MaxVaryingComponents",
>         state->Const.MaxVaryingFloats)__;
>               }
>
>         -   if (add_deprecated) {
>         -      for (unsigned i = 0
>         -             ; i < Elements(builtin_110___deprecated_vs_variables)
>         -             ; i++) {
>         -        add_builtin_variable(__instructions, state->symbols,
>         -                             &
>         builtin_110_deprecated_vs___variables[i]);
>         -      }
>         -   }
>         -   generate_110_uniforms(__instructions, state, add_deprecated);
>         -
>         -   if (add_deprecated) {
>         -      /* From page 54 (page 60 of the PDF) of the GLSL 1.20 spec:
>         -       *
>         -       *     "As with all arrays, indices used to subscript
>         gl_TexCoord must
>         -       *     either be an integral constant expressions, or
>         this array must be
>         -       *     re-declared by the shader with a size. The size
>         can be at most
>         -       *     gl_MaxTextureCoords. Using indexes close to 0 may
>         aid the
>         -       *     implementation in preserving varying resources."
>         +   if (compatibility) {
>         +      /* Note: gl_MaxLights stopped being listed as an explicit
>         constant in
>         +       * GLSL 1.30, however it continues to be referred to (as
>         a minimum size
>         +       * for compatibility-mode uniforms) all the way up
>         through GLSL 4.30, so
>         +       * this seems like it was probably an oversight.
>                   */
>         -      const glsl_type *const vec4_array_type =
>         -         glsl_type::get_array_instance(__glsl_type::vec4_type, 0);
>         +      add_const("gl_MaxLights", state->Const.MaxLights);
>
>         -      add_variable(instructions, state->symbols,
>         -                   "gl_TexCoord", vec4_array_type,
>         ir_var_shader_out,
>         -                   VARYING_SLOT_TEX0);
>         -   }
>         -
>         -   generate_ARB_draw_buffers___variables(instructions, state,
>         false,
>         -                                      vertex_shader);
>         -}
>         -
>         -
>         -static void
>         -generate_120_vs_variables(__exec_list *instructions,
>         -                         struct _mesa_glsl_parse_state *state,
>         -                         bool add_deprecated)
>         -{
>         -   /* GLSL version 1.20 did not add any built-in variables in
>         the vertex
>         -    * shader.
>         -    */
>         -   generate_110_vs_variables(__instructions, state,
>         add_deprecated);
>         -}
>         +      add_const("gl_MaxClipPlanes", state->Const.MaxClipPlanes);
>
>         +      /* Note: gl_MaxTextureUnits wasn't made
>         compatibility-only until GLSL
>         +       * 1.50, however this seems like it was probably an
>         oversight.
>         +       */
>         +      add_const("gl_MaxTextureUnits"__,
>         state->Const.MaxTextureUnits);
>
>         -static void
>         -generate_130_uniforms(exec___list *instructions,
>         -                     struct _mesa_glsl_parse_state *state)
>         -{
>         -   glsl_symbol_table *const symtab = state->symbols;
>         -
>         -   add_builtin_constant(__instructions, symtab,
>         "gl_MaxClipDistances",
>         -                        state->Const.MaxClipPlanes);
>         -   add_builtin_constant(__instructions, symtab,
>         "gl_MaxVaryingComponents",
>         -                       state->Const.MaxVaryingFloats)__;
>         -
>         -   if (state->ARB_shading_language___420pack_enable) {
>         -      add_builtin_constant(__instructions, symtab,
>         "gl_MinProgramTexelOffset",
>         -                           state->Const.__MinProgramTexelOffset);
>         -      add_builtin_constant(__instructions, symtab,
>         "gl_MaxProgramTexelOffset",
>         -                           state->Const.__MaxProgramTexelOffset);
>         +      /* Note: gl_MaxTextureCoords was left out of GLSL 1.40,
>         but it was
>         +       * re-introduced in GLSL 1.50, so this seems like it was
>         probably an
>         +       * oversight.
>         +       */
>         +      add_const("gl___MaxTextureCoords",
>         state->Const.MaxTextureCoords)__;
>               }
>            }
>
>
>         -static void
>         -generate_130_vs_variables(__exec_list *instructions,
>         -                         struct _mesa_glsl_parse_state *state,
>         -                         bool add_deprecated)
>         +/**
>         + * Generate uniform variables (which exist in all types of
>         shaders).
>         + */
>         +void
>         +builtin_variable_generator::__generate_uniforms()
>            {
>         -   generate_120_vs_variables(__instructions, state,
>         add_deprecated);
>         -
>         -   for (unsigned i = 0; i <
>         Elements(builtin_130_vs___variables); i++) {
>         -      add_builtin_variable(__instructions, state->symbols,
>         -                          & builtin_130_vs_variables[i]);
>         -   }
>         +   add_uniform(typ("gl___DepthRangeParameters"), "gl_DepthRange");
>         +   add_uniform(array(vec4_t, VERT_ATTRIB_MAX),
>         "gl_CurrentAttribVertMESA");
>         +   add_uniform(array(vec4_t, VARYING_SLOT_MAX),
>         "gl_CurrentAttribFragMESA");
>         +
>         +   if (compatibility) {
>         +      add_uniform(mat4_t, "gl_ModelViewMatrix");
>         +      add_uniform(mat4_t, "gl_ProjectionMatrix");
>         +      add_uniform(mat4_t, "gl_ModelViewProjectionMatrix"__);
>         +      add_uniform(mat3_t, "gl_NormalMatrix");
>         +      add_uniform(mat4_t, "gl_ModelViewMatrixInverse");
>         +      add_uniform(mat4_t, "gl_ProjectionMatrixInverse");
>         +      add_uniform(mat4_t,
>         "gl___ModelViewProjectionMatrixInver__se");
>         +      add_uniform(mat4_t, "gl_ModelViewMatrixTranspose")__;
>         +      add_uniform(mat4_t, "gl_ProjectionMatrixTranspose"__);
>         +      add_uniform(mat4_t,
>         "gl___ModelViewProjectionMatrixTrans__pose");
>         +      add_uniform(mat4_t,
>         "gl___ModelViewMatrixInverseTranspos__e");
>         +      add_uniform(mat4_t,
>         "gl___ProjectionMatrixInverseTranspo__se");
>         +      add_uniform(mat4_t,
>         "gl___ModelViewProjectionMatrixInver__seTranspose");
>         +      add_uniform(float_t, "gl_NormalScale");
>         +      add_uniform(typ("gl___LightModelParameters"),
>         "gl_LightModel");
>         +      add_uniform(vec2_t, "gl_BumpRotMatrix0MESA");
>         +      add_uniform(vec2_t, "gl_BumpRotMatrix1MESA");
>         +      add_uniform(vec4_t, "gl_FogParamsOptimizedMESA");
>
>         -   generate_130_uniforms(__instructions, state);
>         -
>         -   /* From the GLSL 1.30 spec, section 7.1 (Vertex Shader Special
>         -    * Variables):
>         -    *
>         -    *   The gl_ClipDistance array is predeclared as unsized and
>         must
>         -    *   be sized by the shader either redeclaring it with a size or
>         -    *   indexing it only with integral constant expressions.
>         -    *
>         -    * We represent this in Mesa by initially declaring the array as
>         -    * size 0.
>         -    */
>         -   const glsl_type *const clip_distance_array_type =
>         -      glsl_type::get_array_instance(__glsl_type::float_type, 0);
>         -
>         -   add_variable(instructions, state->symbols,
>         -               "gl_ClipDistance", clip_distance_array_type,
>         ir_var_shader_out,
>         -                VARYING_SLOT_CLIP_DIST0);
>         +      const glsl_type *const mat4_array_type =
>         +        array(mat4_t, state->Const.MaxTextureCoords)__;
>         +      add_uniform(mat4_array_type, "gl_TextureMatrix");
>         +      add_uniform(mat4_array_type, "gl_TextureMatrixInverse");
>         +      add_uniform(mat4_array_type, "gl_TextureMatrixTranspose");
>         +      add_uniform(mat4_array_type,
>         "gl___TextureMatrixInverseTranspose"__);
>
>         -   generate_AMD_vertex_shader___layer_variables(instructions,
>         state, false,
>         -                                              vertex_shader);
>         -}
>         +      add_uniform(array(vec4_t, state->Const.MaxClipPlanes),
>         "gl_ClipPlane");
>         +      add_uniform(typ("gl___PointParameters"), "gl_Point");
>
>         +      const glsl_type *const material_parameters_type =
>         +        typ("gl_MaterialParameters");
>         +      add_uniform(material___parameters_type, "gl_FrontMaterial");
>         +      add_uniform(material___parameters_type, "gl_BackMaterial");
>
>         -static void
>         -initialize_vs_variables(exec___list *instructions,
>         -                       struct _mesa_glsl_parse_state *state)
>         -{
>         -   if (state->es_shader) {
>         -      switch (state->language_version) {
>         -      case 100:
>         -         generate_100ES_vs_variables(__instructions, state);
>         -         break;
>         -      case 300:
>         -         generate_300ES_vs_variables(__instructions, state);
>         -         break;
>         -      default:
>         -         assert(!"Unexpected language version");
>         -         break;
>         -      }
>         -   } else {
>         -      switch (state->language_version) {
>         -      case 110:
>         -         generate_110_vs_variables(__instructions, state, true);
>         -         break;
>         -      case 120:
>         -         generate_120_vs_variables(__instructions, state, true);
>         -         break;
>         -      case 130:
>         -         generate_130_vs_variables(__instructions, state, true);
>         -         break;
>         -      case 140:
>         -      case 150:
>         -         generate_130_vs_variables(__instructions, state, false);
>         -         break;
>         -      default:
>         -         assert(!"Unexpected language version");
>         -         break;
>         -      }
>         -   }
>         +      add_uniform(array(typ("gl___LightSourceParameters"),
>         +                        state->Const.MaxLights),
>         +                  "gl_LightSource");
>
>         -   generate_ARB_draw_instanced___variables(instructions, state,
>         false,
>         -                                        vertex_shader);
>         -}
>         +      const glsl_type *const light_model_products_type =
>         +         typ("gl_LightModelProducts");
>         +      add_uniform(light_model___products_type,
>         "gl_FrontLightModelProduct");
>         +      add_uniform(light_model___products_type,
>         "gl_BackLightModelProduct");
>
>         +      const glsl_type *const light_products_type =
>         +         array(typ("gl_LightProducts"), state->Const.MaxLights);
>         +      add_uniform(light_products___type, "gl_FrontLightProduct");
>         +      add_uniform(light_products___type, "gl_BackLightProduct");
>
>         -/* This function should only be called for ES, not desktop GL. */
>         -static void
>         -generate_100ES_fs_variables(__exec_list *instructions,
>         -                         struct _mesa_glsl_parse_state *state)
>         -{
>         -   for (unsigned i = 0; i <
>         Elements(builtin_core_fs___variables); i++) {
>         -      add_builtin_variable(__instructions, state->symbols,
>         -                          & builtin_core_fs_variables[i]);
>         -   }
>         +      add_uniform(array(vec4_t, state->Const.MaxTextureUnits),
>         +                  "gl_TextureEnvColor");
>
>         -   for (unsigned i = 0; i <
>         Elements(builtin_100ES_fs___variables); i++) {
>         -      add_builtin_variable(__instructions, state->symbols,
>         -                          & builtin_100ES_fs_variables[i])__;
>         +      const glsl_type *const texcoords_vec4 =
>         +        array(vec4_t, state->Const.MaxTextureCoords)__;
>         +      add_uniform(texcoords_vec4, "gl_EyePlaneS");
>         +      add_uniform(texcoords_vec4, "gl_EyePlaneT");
>         +      add_uniform(texcoords_vec4, "gl_EyePlaneR");
>         +      add_uniform(texcoords_vec4, "gl_EyePlaneQ");
>         +      add_uniform(texcoords_vec4, "gl_ObjectPlaneS");
>         +      add_uniform(texcoords_vec4, "gl_ObjectPlaneT");
>         +      add_uniform(texcoords_vec4, "gl_ObjectPlaneR");
>         +      add_uniform(texcoords_vec4, "gl_ObjectPlaneQ");
>         +
>         +      add_uniform(typ("gl___FogParameters"), "gl_Fog");
>               }
>         -
>         -   generate_100ES_uniforms(__instructions, state);
>         -
>         -   generate_ARB_draw_buffers___variables(instructions, state,
>         false,
>         -                                      fragment_shader);
>            }
>
>         -static void
>         -generate_300ES_fs_variables(__exec_list *instructions,
>         -                         struct _mesa_glsl_parse_state *state)
>         -{
>         -   /* Note: we don't add builtin_core_fs_variables, because it
>         contains
>         -    * gl_FragColor, which is not in GLSL 3.00 ES.
>         -    */
>         -
>         -   for (unsigned i = 0; i <
>         Elements(builtin_300ES_fs___variables); i++) {
>         -      add_builtin_variable(__instructions, state->symbols,
>         -                          & builtin_300ES_fs_variables[i])__;
>         -   }
>         -
>         -   generate_300ES_uniforms(__instructions, state);
>
>         -   generate_ARB_draw_buffers___variables(instructions, state,
>         false,
>         -                                      fragment_shader);
>         -}
>         -
>         -static void
>         -generate_110_fs_variables(__exec_list *instructions,
>         -                         struct _mesa_glsl_parse_state *state,
>         -                         bool add_deprecated)
>         +/**
>         + * Generate variables which only exist in vertex shaders.
>         + */
>         +void
>         +builtin_variable_generator::__generate_vs_special_vars()
>            {
>         -   for (unsigned i = 0; i <
>         Elements(builtin_core_fs___variables); i++) {
>         -      add_builtin_variable(__instructions, state->symbols,
>         -                          & builtin_core_fs_variables[i]);
>         -   }
>         -
>         -   for (unsigned i = 0; i <
>         Elements(builtin_110_fs___variables); i++) {
>         -      add_builtin_variable(__instructions, state->symbols,
>         -                          & builtin_110_fs_variables[i]);
>         +   if (state->is_version(130, 300))
>         +      add_system_value(SYSTEM_VALUE___VERTEX_ID, int_t,
>         "gl_VertexID");
>         +   if (state->ARB_draw_instanced___enable)
>         +      add_system_value(SYSTEM_VALUE___INSTANCE_ID, int_t,
>         "gl_InstanceIDARB");
>         +   if (state->ARB_draw_instanced___enable ||
>         state->is_version(140, 300))
>         +      add_system_value(SYSTEM_VALUE___INSTANCE_ID, int_t,
>         "gl_InstanceID");
>         +   if (state->AMD_vertex_shader___layer_enable)
>         +      add_output(VARYING_SLOT_LAYER, int_t, "gl_Layer");
>         +   if (compatibility) {
>         +      add_input(VERT_ATTRIB_POS, vec4_t, "gl_Vertex");
>         +      add_input(VERT_ATTRIB_NORMAL, vec3_t, "gl_Normal");
>         +      add_input(VERT_ATTRIB_COLOR0, vec4_t, "gl_Color");
>         +      add_input(VERT_ATTRIB_COLOR1, vec4_t, "gl_SecondaryColor");
>         +      add_input(VERT_ATTRIB_TEX0, vec4_t, "gl_MultiTexCoord0");
>         +      add_input(VERT_ATTRIB_TEX1, vec4_t, "gl_MultiTexCoord1");
>         +      add_input(VERT_ATTRIB_TEX2, vec4_t, "gl_MultiTexCoord2");
>         +      add_input(VERT_ATTRIB_TEX3, vec4_t, "gl_MultiTexCoord3");
>         +      add_input(VERT_ATTRIB_TEX4, vec4_t, "gl_MultiTexCoord4");
>         +      add_input(VERT_ATTRIB_TEX5, vec4_t, "gl_MultiTexCoord5");
>         +      add_input(VERT_ATTRIB_TEX6, vec4_t, "gl_MultiTexCoord6");
>         +      add_input(VERT_ATTRIB_TEX7, vec4_t, "gl_MultiTexCoord7");
>         +      add_input(VERT_ATTRIB_FOG, float_t, "gl_FogCoord");
>               }
>         -
>         -   if (add_deprecated) {
>         -      for (unsigned i = 0
>         -             ; i < Elements(builtin_110___deprecated_fs_variables)
>         -             ; i++) {
>         -        add_builtin_variable(__instructions, state->symbols,
>         -                             &
>         builtin_110_deprecated_fs___variables[i]);
>         -      }
>         -   }
>         -
>         -   generate_110_uniforms(__instructions, state, add_deprecated);
>         -
>         -   if (add_deprecated) {
>         -      /* From page 54 (page 60 of the PDF) of the GLSL 1.20 spec:
>         -       *
>         -       *     "As with all arrays, indices used to subscript
>         gl_TexCoord must
>         -       *     either be an integral constant expressions, or
>         this array must be
>         -       *     re-declared by the shader with a size. The size
>         can be at most
>         -       *     gl_MaxTextureCoords. Using indexes close to 0 may
>         aid the
>         -       *     implementation in preserving varying resources."
>         -       */
>         -      const glsl_type *const vec4_array_type =
>         -         glsl_type::get_array_instance(__glsl_type::vec4_type, 0);
>         -
>         -      add_variable(instructions, state->symbols,
>         -                   "gl_TexCoord", vec4_array_type,
>         ir_var_shader_in,
>         -                   VARYING_SLOT_TEX0);
>         -   }
>         -
>         -   generate_ARB_draw_buffers___variables(instructions, state,
>         false,
>         -                                      fragment_shader);
>            }
>
>
>         -static void
>         -generate_ARB_draw_buffers___variables(exec_list *instructions,
>         -                                   struct
>         _mesa_glsl_parse_state *state,
>         -                                   bool warn,
>         _mesa_glsl_parser_targets target)
>         +/**
>         + * Generate variables which only exist in geometry shaders.
>         + */
>         +void
>         +builtin_variable_generator::__generate_gs_special_vars()
>            {
>         -   /* gl_MaxDrawBuffers is available in all shader stages.
>         -    */
>         -   ir_variable *const mdb =
>         -      add_builtin_constant(__instructions, state->symbols,
>         "gl_MaxDrawBuffers",
>         -                          state->Const.MaxDrawBuffers);
>         -
>         -   if (warn)
>         -      mdb->warn_extension = "GL_ARB_draw_buffers";
>         +   add_output(VARYING_SLOT_LAYER, int_t, "gl_Layer");
>
>         -   /* gl_FragData is only available in the fragment shader.
>         -    * It is not present in GLSL 3.00 ES.
>         +   /* Although gl_PrimitiveID appears in tessellation control
>         and tessellation
>         +    * evaluation shaders, it has a different function there
>         than it has in
>         +    * geometry shaders, so we treat it (and its counterpart
>         gl_PrimitiveIDIn)
>         +    * as special geometry shader variables.
>         +    *
>         +    * Note that although the general convention of suffixing
>         geometry shader
>         +    * input varyings with "In" was not adopted into GLSL 1.50,
>         it is used in
>         +    * the specific case of gl_PrimitiveIDIn.  So we don't need
>         to treat
>         +    * gl_PrimitiveIDIn as an {ARB,EXT}_geometry_shader4-__only
>         variable.
>                */
>         -   if (target == fragment_shader && !state->is_version(0, 300)) {
>         -      const glsl_type *const vec4_array_type =
>         -        glsl_type::get_array_instance(__glsl_type::vec4_type,
>         -                                      state->Const.MaxDrawBuffers);
>         -
>         -      ir_variable *const fd =
>         -        add_variable(instructions, state->symbols,
>         -                     "gl_FragData", vec4_array_type,
>         -                     ir_var_shader_out, FRAG_RESULT_DATA0);
>         -
>         -      if (warn)
>         -        fd->warn_extension = "GL_ARB_draw_buffers";
>         -   }
>         +   add_input(VARYING_SLOT___PRIMITIVE_ID, int_t,
>         "gl_PrimitiveIDIn");
>         +   add_output(VARYING_SLOT___PRIMITIVE_ID, int_t,
>         "gl_PrimitiveID");
>            }
>
>
>         -static void
>         -generate_ARB_draw_instanced___variables(exec_list *instructions,
>         -                                      struct
>         _mesa_glsl_parse_state *state,
>         -                                      bool warn,
>         -                                      _mesa_glsl_parser_targets
>         target)
>         +/**
>         + * Generate variables which only exist in fragment shaders.
>         + */
>         +void
>         +builtin_variable_generator::__generate_fs_special_vars()
>            {
>         -   /* gl_InstanceIDARB is only available in the vertex shader.
>         +   add_input(VARYING_SLOT_POS, vec4_t, "gl_FragCoord");
>         +   add_input(VARYING_SLOT_FACE, bool_t, "gl_FrontFacing");
>         +   if (state->is_version(120, 100))
>         +      add_input(VARYING_SLOT_PNTC, vec2_t, "gl_PointCoord");
>         +
>         +   /* gl_FragColor and gl_FragData were deprecated starting in
>         desktop GLSL
>         +    * 1.30, and were relegated to the compatibility profile in
>         GLSL 4.20.
>         +    * They were removed from GLSL ES 3.00.
>                */
>         -   if (target != vertex_shader)
>         -      return;
>         -
>         -   if (state->ARB_draw_instanced___enable) {
>         -      ir_variable *inst =
>         -         add_variable(instructions, state->symbols,
>         -                     "gl_InstanceIDARB", glsl_type::int_type,
>         -                     ir_var_system_value,
>         SYSTEM_VALUE_INSTANCE_ID);
>         -
>         -      if (warn)
>         -         inst->warn_extension = "GL_ARB_draw_instanced";
>         +   if (compatibility || !state->is_version(420, 300)) {
>         +      add_output(FRAG_RESULT_COLOR, vec4_t, "gl_FragColor");
>         +      add_output(FRAG_RESULT_DATA0,
>         +                 array(vec4_t, state->Const.MaxDrawBuffers),
>         "gl_FragData");
>               }
>
>         -   bool available_in_core = state->is_version(140, 300);
>         -   if (state->ARB_draw_instanced___enable || available_in_core) {
>         -      /* Originally ARB_draw_instanced only specified that ARB
>         decorated name.
>         -       * Since no vendor actually implemented that behavior and
>         some apps use
>         -       * the undecorated name, the extension now specifies that
>         both names are
>         -       * available.
>         -       */
>         -      ir_variable *inst =
>         -        add_variable(instructions, state->symbols,
>         -                     "gl_InstanceID", glsl_type::int_type,
>         -                     ir_var_system_value,
>         SYSTEM_VALUE_INSTANCE_ID);
>         -
>         -      if (!available_in_core && warn)
>         -         inst->warn_extension = "GL_ARB_draw_instanced";
>         -   }
>         -}
>         -
>         -static void
>         -generate_AMD_vertex_shader___layer_variables(exec_list
>         *instructions,
>         -                                           struct
>         _mesa_glsl_parse_state *state,
>         -                                           bool warn,
>         -
>         _mesa_glsl_parser_targets target)
>         -{
>         -   /* gl_Layer is only available in the vertex shader for the
>         -    * AMD_vertex_shader_layer extension. It will also be
>         available in the
>         -    * geometry shader when GLSL 1.50 is supported.
>         +   /* gl_FragDepth has always been in desktop GLSL, but did not
>         appear in GLSL
>         +    * ES 1.00.
>                */
>         -   if (target != vertex_shader)
>         -      return;
>         +   if (state->is_version(110, 300))
>         +      add_output(FRAG_RESULT_DEPTH, float_t, "gl_FragDepth");
>
>         -   if (state->AMD_vertex_shader___layer_enable) {
>         -      ir_variable *inst =
>         -         add_variable(instructions, state->symbols,
>         -                      "gl_Layer", glsl_type::int_type,
>         -                      ir_var_shader_out, VARYING_SLOT_LAYER);
>         -
>         -      if (warn)
>         -         inst->warn_extension = "GL_AMD_vertex_shader_layer";
>         +   if (state->ARB_shader_stencil___export_enable) {
>         +      ir_variable *const var =
>         +         add_output(FRAG_RESULT___STENCIL, int_t,
>         "gl_FragStencilRefARB");
>         +      if (state->ARB_shader_stencil___export_warn)
>         +         var->warn_extension = "GL_ARB_shader_stencil_export"__;
>               }
>         -}
>         -
>         -static void
>         -generate_ARB_shader_stencil___export_variables(exec_list
>         *instructions,
>         -                                            struct
>         _mesa_glsl_parse_state *state,
>         -                                            bool warn)
>         -{
>         -   /* gl_FragStencilRefARB is only available in the fragment
>         shader.
>         -    */
>         -   ir_variable *const fd =
>         -      add_variable(instructions, state->symbols,
>         -                  "gl_FragStencilRefARB", glsl_type::int_type,
>         -                  ir_var_shader_out, FRAG_RESULT_STENCIL);
>         -
>         -   if (warn)
>         -      fd->warn_extension = "GL_ARB_shader_stencil_export"__;
>         -}
>
>         -static void
>         -generate_AMD_shader_stencil___export_variables(exec_list
>         *instructions,
>         -                                            struct
>         _mesa_glsl_parse_state *state,
>         -                                            bool warn)
>         -{
>         -   /* gl_FragStencilRefAMD is only available in the fragment
>         shader.
>         -    */
>         -   ir_variable *const fd =
>         -      add_variable(instructions, state->symbols,
>         -                  "gl_FragStencilRefAMD", glsl_type::int_type,
>         -                  ir_var_shader_out, FRAG_RESULT_STENCIL);
>         -
>         -   if (warn)
>         -      fd->warn_extension = "GL_AMD_shader_stencil_export"__;
>         -}
>         -
>         -static void
>         -generate_120_fs_variables(__exec_list *instructions,
>         -                         struct _mesa_glsl_parse_state *state,
>         -                         bool add_deprecated)
>         -{
>         -   generate_110_fs_variables(__instructions, state,
>         add_deprecated);
>         -
>         -   for (unsigned i = 0
>         -          ; i < Elements(builtin_120_fs___variables)
>         -          ; i++) {
>         -      add_builtin_variable(__instructions, state->symbols,
>         -                          & builtin_120_fs_variables[i]);
>         +   if (state->AMD_shader_stencil___export_enable) {
>         +      ir_variable *const var =
>         +         add_output(FRAG_RESULT___STENCIL, int_t,
>         "gl_FragStencilRefAMD");
>         +      if (state->AMD_shader_stencil___export_warn)
>         +         var->warn_extension = "GL_AMD_shader_stencil_export"__;
>               }
>            }
>
>         -static void
>         -generate_fs_clipdistance(__exec_list *instructions,
>         -                        struct _mesa_glsl_parse_state *state)
>         -{
>         -   /* From the GLSL 1.30 spec, section 7.2 (Fragment Shader Special
>         -    * Variables):
>         -    *
>         -    *   The built-in input variable gl_ClipDistance array
>         contains linearly
>         -    *   interpolated values for the vertex values written by
>         the vertex shader
>         -    *   to the gl_ClipDistance vertex output variable. This
>         array must be
>         -    *   sized in the fragment shader either implicitly or
>         explicitly to be the
>         -    *   same size as it was sized in the vertex shader.
>         -    *
>         -    * In other words, the array must be pre-declared as
>         implicitly sized.  We
>         -    * represent this in Mesa by initially declaring the array
>         as size 0.
>         -    */
>         -   const glsl_type *const clip_distance_array_type =
>         -      glsl_type::get_array_instance(__glsl_type::float_type, 0);
>         -
>         -   add_variable(instructions, state->symbols,
>         -               "gl_ClipDistance", clip_distance_array_type,
>         ir_var_shader_in,
>         -                VARYING_SLOT_CLIP_DIST0);
>         -}
>
>         -static void
>         -generate_130_fs_variables(__exec_list *instructions,
>         -                         struct _mesa_glsl_parse_state *state)
>         +/**
>         + * Add a single "varying" variable.  The variable's type and
>         direction (input
>         + * or output) are adjusted as appropriate for the type of
>         shader being
>         + * compiled.  For geometry shaders using
>         {ARB,EXT}_geometry_shader4,
>         + * name_as_gs_input is used for the input (to avoid ambiguity).
>         + */
>         +void
>         +builtin_variable_generator::__add_varying(int slot, const
>         glsl_type *type,
>         +                                        const char *name,
>         +                                        const char
>         *name_as_gs_input)
>            {
>         -   generate_120_fs_variables(__instructions, state, true);
>         -
>         -   generate_130_uniforms(__instructions, state);
>         -   generate_fs_clipdistance(__instructions, state);
>         +   switch (state->target) {
>         +   case geometry_shader:
>         +      add_input(slot, array(type, 0), name_as_gs_input);
>         +      /* Fall through: */
>
>
>     This needs to be /* FALLTHROUGH */ or /* FALLTHRU */ because some
>     static analysis tools look specifically for one of those strings.
>
>
> Ok, I'll change that.
>
>
>
>         +   case vertex_shader:
>         +      add_output(slot, type, name);
>         +      break;
>         +   case fragment_shader:
>         +      add_input(slot, type, name);
>         +      break;
>         +   }
>            }
>
>
>         -static void
>         -generate_140_fs_variables(__exec_list *instructions,
>         -                         struct _mesa_glsl_parse_state *state)
>         -{
>         -   generate_120_fs_variables(__instructions, state, false);
>         -
>         -   generate_130_uniforms(__instructions, state);
>         -   generate_fs_clipdistance(__instructions, state);
>         -}
>         -
>         -static void
>         -initialize_fs_variables(exec___list *instructions,
>         -                       struct _mesa_glsl_parse_state *state)
>         +/**
>         + * Generate variables that are used to communicate data from
>         one shader stage
>         + * to the next ("varyings").
>         + */
>         +void
>         +builtin_variable_generator::__generate_varyings()
>            {
>         -   if (state->es_shader) {
>         -      switch (state->language_version) {
>         -      case 100:
>         -         generate_100ES_fs_variables(__instructions, state);
>         -         break;
>         -      case 300:
>         -         generate_300ES_fs_variables(__instructions, state);
>         -         break;
>         -      default:
>         -         assert(!"Unexpected language version");
>         -         break;
>         -      }
>         -   } else {
>         -      switch (state->language_version) {
>         -      case 110:
>         -         generate_110_fs_variables(__instructions, state, true);
>         -         break;
>         -      case 120:
>         -         generate_120_fs_variables(__instructions, state, true);
>         -         break;
>         -      case 130:
>         -         generate_130_fs_variables(__instructions, state);
>         -         break;
>         -      case 140:
>         -      case 150:
>         -         generate_140_fs_variables(__instructions, state);
>         -         break;
>         -      default:
>         -         assert(!"Unexpected language version");
>         -         break;
>         +#define ADD_VARYING(loc, typ, name) \
>         +   add_varying(loc, typ, name, name "In")
>         +
>         +   /* gl_Position and gl_PointSize are not visible from
>         fragment shaders. */
>         +   if (state->target != fragment_shader) {
>         +      ADD_VARYING(VARYING_SLOT_POS, vec4_t, "gl_Position");
>         +      ADD_VARYING(VARYING_SLOT_PSIZ, float_t, "gl_PointSize");
>         +   }
>         +
>         +   if (state->is_version(130, 0)) {
>         +       ADD_VARYING(VARYING_SLOT_CLIP___DIST0, array(float_t, 0),
>         +                   "gl_ClipDistance");
>         +   }
>         +
>         +   if (compatibility) {
>         +      ADD_VARYING(VARYING_SLOT_TEX0, array(vec4_t, 0),
>         "gl_TexCoord");
>         +      ADD_VARYING(VARYING_SLOT_FOGC, float_t, "gl_FogFragCoord");
>         +      if (state->target == fragment_shader) {
>         +         ADD_VARYING(VARYING_SLOT_COL0, vec4_t, "gl_Color");
>         +         ADD_VARYING(VARYING_SLOT_COL1, vec4_t,
>         "gl_SecondaryColor");
>         +      } else {
>         +         ADD_VARYING(VARYING_SLOT_CLIP___VERTEX, vec4_t,
>         "gl_ClipVertex");
>         +         ADD_VARYING(VARYING_SLOT_COL0, vec4_t, "gl_FrontColor");
>         +         ADD_VARYING(VARYING_SLOT_BFC0, vec4_t, "gl_BackColor");
>         +         ADD_VARYING(VARYING_SLOT_COL1, vec4_t,
>         "gl_FrontSecondaryColor");
>         +         ADD_VARYING(VARYING_SLOT_BFC1, vec4_t,
>         "gl_BackSecondaryColor");
>                  }
>               }
>         +}
>
>         -   if (state->ARB_shader_stencil___export_enable)
>         -
>           generate_ARB_shader_stencil___export_variables(instructions,
>         state,
>         -
>           state->ARB_shader_stencil___export_warn);
>
>         -   if (state->AMD_shader_stencil___export_enable)
>         -
>           generate_AMD_shader_stencil___export_variables(instructions,
>         state,
>         -
>           state->AMD_shader_stencil___export_warn);
>         -}
>         +}; /* Anonymous namespace */
>         +
>
>            void
>            _mesa_glsl_initialize___variables(exec_list *instructions,
>                                          struct _mesa_glsl_parse_state
>         *state)
>            {
>         +   builtin_variable_generator gen(instructions, state);
>         +
>         +   gen.generate_constants();
>         +   gen.generate_uniforms();
>         +
>         +   gen.generate_varyings();
>         +
>               switch (state->target) {
>               case vertex_shader:
>         -      initialize_vs_variables(__instructions, state);
>         +      gen.generate_vs_special_vars()__;
>                  break;
>               case geometry_shader:
>         +      gen.generate_gs_special_vars()__;
>                  break;
>               case fragment_shader:
>         -      initialize_fs_variables(__instructions, state);
>         +      gen.generate_fs_special_vars()__;
>                  break;
>               }
>            }



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