glsl: Rework builtin_variables.cpp to reduce code duplication.

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 patch doesn't introduce any functional changes (since geometry
shaders haven't been enabled yet).

Reviewed-by: Matt Turner <[email protected]>

v2: Rename "typ" -> "type".  Add blank line between inline functions
and declarations in builtin_variable_generator class.  Use the
standard comment "/* FALLTHROUGH */" for compatibility with static
code analysis tools.

Reviewed-by: Kenneth Graunke <[email protected]>

1 files changed, 368 insertions, 761 deletions

diff --git a/src/glsl/builtin_variables.cpp b/src/glsl/builtin_variables.cpp
index eccd15a7769..1e88b6a73be 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_ModelViewProjectionMatrixInverse" },
-   { ir_var_uniform, -1, "mat4", "gl_ModelViewMatrixTranspose" },
-   { ir_var_uniform, -1, "mat4", "gl_ProjectionMatrixTranspose" },
-   { ir_var_uniform, -1, "mat4", "gl_ModelViewProjectionMatrixTranspose" },
-   { ir_var_uniform, -1, "mat4", "gl_ModelViewMatrixInverseTranspose" },
-   { ir_var_uniform, -1, "mat4", "gl_ProjectionMatrixInverseTranspose" },
-   { ir_var_uniform, -1, "mat4", "gl_ModelViewProjectionMatrixInverseTranspose" },
-   { 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 +290,93 @@ 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 *type(const char *name)
+   {
+      return symtab->get_type(name);
+   }
+
+   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);
+   }
+
+   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);
+   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;
+};
+
+
+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 +411,12 @@ 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 +459,11 @@ 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 +471,355 @@ 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_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);
-}
+      add_const("gl_MaxLights", state->Const.MaxLights);
 
+      add_const("gl_MaxClipPlanes", state->Const.MaxClipPlanes);
 
-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);
-}
-
+      /* 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]);
-   }
-
-   generate_130_uniforms(instructions, state);
+   add_uniform(type("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_ModelViewProjectionMatrixInverse");
+      add_uniform(mat4_t, "gl_ModelViewMatrixTranspose");
+      add_uniform(mat4_t, "gl_ProjectionMatrixTranspose");
+      add_uniform(mat4_t, "gl_ModelViewProjectionMatrixTranspose");
+      add_uniform(mat4_t, "gl_ModelViewMatrixInverseTranspose");
+      add_uniform(mat4_t, "gl_ProjectionMatrixInverseTranspose");
+      add_uniform(mat4_t, "gl_ModelViewProjectionMatrixInverseTranspose");
+      add_uniform(float_t, "gl_NormalScale");
+      add_uniform(type("gl_LightModelParameters"), "gl_LightModel");
+      add_uniform(vec2_t, "gl_BumpRotMatrix0MESA");
+      add_uniform(vec2_t, "gl_BumpRotMatrix1MESA");
+      add_uniform(vec4_t, "gl_FogParamsOptimizedMESA");
 
-   /* 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);
+      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");
 
-   add_variable(instructions, state->symbols,
-		"gl_ClipDistance", clip_distance_array_type, ir_var_shader_out,
-                VARYING_SLOT_CLIP_DIST0);
+      add_uniform(array(vec4_t, state->Const.MaxClipPlanes), "gl_ClipPlane");
+      add_uniform(type("gl_PointParameters"), "gl_Point");
 
-   generate_AMD_vertex_shader_layer_variables(instructions, state, false,
-                                              vertex_shader);
-}
+      const glsl_type *const material_parameters_type =
+	 type("gl_MaterialParameters");
+      add_uniform(material_parameters_type, "gl_FrontMaterial");
+      add_uniform(material_parameters_type, "gl_BackMaterial");
 
+      add_uniform(array(type("gl_LightSourceParameters"),
+                        state->Const.MaxLights),
+                  "gl_LightSource");
 
-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;
-      }
-   }
-
-   generate_ARB_draw_instanced_variables(instructions, state, false,
-					 vertex_shader);
-}
+      const glsl_type *const light_model_products_type =
+         type("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(type("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(type("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 (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]);
-      }
+   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");
    }
-
-   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);
+      /* FALLTHROUGH */
+   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, type, name) \
+   add_varying(loc, type, 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;
    }
 }