glsl: Add infrastructure for "hidden" uniforms.

In the compiler, we'd like to generate implicit uniforms for internal
use.  These should not be visible via the GL uniform introspection API.

To support that, we add a new ir_variable::how_declared value of
ir_var_hidden, and plumb that through to gl_uniform_storage.

v2 (idr): Fix some memory management issues in
move_hidden_uniforms_to_end.  The comment block on the function has more
details.

Signed-off-by: Kenneth Graunke <kenneth@whitecape.org>
Signed-off-by: Ian Romanick <ian.d.romanick@intel.com>

src/glsl/ir.h

@@ -342,6 +342,12 @@ enum ir_var_declaration_type {
     * re-declared by the shader.
     */
    ir_var_declared_implicitly,
+
+   /**
+    * Variable is implicitly generated by the compiler and should not be
+    * visible via the API.
+    */
+   ir_var_hidden,
 };
 
 /**

src/glsl/ir_uniform.h

@@ -175,6 +175,12 @@ struct gl_uniform_storage {
     * arrays this is the first element in the array.
     */
    unsigned remap_location;
+
+   /**
+    * This is a compiler-generated uniform that should not be advertised
+    * via the API.
+    */
+   bool hidden;
 };
 
 #ifdef __cplusplus

src/glsl/link_uniforms.cpp

@@ -585,6 +585,8 @@ private:
       this->uniforms[id].driver_storage = NULL;
       this->uniforms[id].storage = this->values;
       this->uniforms[id].atomic_buffer_index = -1;
+      this->uniforms[id].hidden =
+         current_var->data.how_declared == ir_var_hidden;
       if (this->ubo_block_index != -1) {
 	 this->uniforms[id].block_index = this->ubo_block_index;
 
@@ -806,6 +808,50 @@ link_set_image_access_qualifiers(struct gl_shader_program *prog)
    }
 }
 
+/**
+ * Sort the array of uniform storage so that the non-hidden uniforms are first
+ *
+ * This function sorts the list "in place."  This is important because some of
+ * the storage accessible from \c uniforms has \c uniforms as its \c ralloc
+ * context.  If \c uniforms is freed, some other storage will also be freed.
+ */
+static unsigned
+move_hidden_uniforms_to_end(struct gl_shader_program *prog,
+                            struct gl_uniform_storage *uniforms,
+                            unsigned num_elements)
+{
+   struct gl_uniform_storage *sorted_uniforms =
+      ralloc_array(prog, struct gl_uniform_storage, num_elements);
+   unsigned hidden_uniforms = 0;
+   unsigned j = 0;
+
+   /* Add the non-hidden uniforms. */
+   for (unsigned i = 0; i < num_elements; i++) {
+      if (!uniforms[i].hidden)
+         sorted_uniforms[j++] = uniforms[i];
+   }
+
+   /* Add and count the hidden uniforms. */
+   for (unsigned i = 0; i < num_elements; i++) {
+      if (uniforms[i].hidden) {
+         sorted_uniforms[j++] = uniforms[i];
+         hidden_uniforms++;
+      }
+   }
+
+   assert(prog->UniformHash != NULL);
+   prog->UniformHash->clear();
+   for (unsigned i = 0; i < num_elements; i++) {
+      if (sorted_uniforms[i].name != NULL)
+         prog->UniformHash->put(i, sorted_uniforms[i].name);
+   }
+
+   memcpy(uniforms, sorted_uniforms, sizeof(uniforms[0]) * num_elements);
+   ralloc_free(sorted_uniforms);
+
+   return hidden_uniforms;
+}
+
 void
 link_assign_uniform_locations(struct gl_shader_program *prog,
                               unsigned int boolean_true)
@@ -926,6 +972,9 @@ link_assign_uniform_locations(struct gl_shader_program *prog,
              sizeof(prog->_LinkedShaders[i]->SamplerTargets));
    }
 
+   const unsigned hidden_uniforms =
+      move_hidden_uniforms_to_end(prog, uniforms, num_user_uniforms);
+
    /* Reserve all the explicit locations of the active uniforms. */
    for (unsigned i = 0; i < num_user_uniforms; i++) {
       if (uniforms[i].remap_location != UNMAPPED_UNIFORM_LOC) {
@@ -978,6 +1027,7 @@ link_assign_uniform_locations(struct gl_shader_program *prog,
 #endif
 
    prog->NumUserUniformStorage = num_user_uniforms;
+   prog->NumHiddenUniforms = hidden_uniforms;
    prog->UniformStorage = uniforms;
 
    link_set_image_access_qualifiers(prog);

src/mesa/main/mtypes.h

@@ -2843,6 +2843,7 @@ struct gl_shader_program
 
    /* post-link info: */
    unsigned NumUserUniformStorage;
+   unsigned NumHiddenUniforms;
    struct gl_uniform_storage *UniformStorage;
 
    /**

src/mesa/main/shaderapi.c

@@ -565,13 +565,15 @@ get_programiv(struct gl_context *ctx, GLuint program, GLenum pname, GLint *param
       *params = _mesa_longest_attribute_name_length(shProg);
       return;
    case GL_ACTIVE_UNIFORMS:
-      *params = shProg->NumUserUniformStorage;
+      *params = shProg->NumUserUniformStorage - shProg->NumHiddenUniforms;
       return;
    case GL_ACTIVE_UNIFORM_MAX_LENGTH: {
       unsigned i;
       GLint max_len = 0;
+      const unsigned num_uniforms =
+         shProg->NumUserUniformStorage - shProg->NumHiddenUniforms;
 
-      for (i = 0; i < shProg->NumUserUniformStorage; i++) {
+      for (i = 0; i < num_uniforms; i++) {
 	 /* Add one for the terminating NUL character for a non-array, and
 	  * 4 for the "[0]" and the NUL for an array.
 	  */