main, glsl: Add UniformDataDefaults which stores uniform defaults

The ARB_get_program_binary extension requires that uniform values in a
program be restored to their initial value just after linking.

This patch saves off the initial values just after linking. When the
program is restored by glProgramBinary, we can use this to copy the
initial value of uniforms into UniformDataSlots.

V2 (Timothy Arceri):
 - Store UniformDataDefaults only when serializing GLSL as this
   is what we want for both disk cache and ARB_get_program_binary.
   This saves us having to come back later and reset the Uniforms
   on program binary restores.

Signed-off-by: Timothy Arceri <tarceri@itsqueeze.com>
Signed-off-by: Jordan Justen <jordan.l.justen@intel.com> (v1)
Reviewed-by: Tapani Pälli <tapani.palli@intel.com>

src/compiler/glsl/link_uniform_initializers.cpp

@@ -357,5 +357,7 @@ link_set_uniform_initializers(struct gl_shader_program *prog,
       }
    }
 
+   memcpy(prog->data->UniformDataDefaults, prog->data->UniformDataSlots,
+          sizeof(union gl_constant_value) * prog->data->NumUniformDataSlots);
    ralloc_free(mem_ctx);
 }

src/compiler/glsl/link_uniforms.cpp

@@ -1365,6 +1365,9 @@ link_assign_uniform_storage(struct gl_context *ctx,
                                                  prog->data->NumUniformStorage);
       data = rzalloc_array(prog->data->UniformStorage,
                            union gl_constant_value, num_data_slots);
+      prog->data->UniformDataDefaults =
+         rzalloc_array(prog->data->UniformStorage,
+                       union gl_constant_value, num_data_slots);
    } else {
       data = prog->data->UniformDataSlots;
    }

src/compiler/glsl/serialize.cpp

@@ -449,7 +449,10 @@ write_uniforms(struct blob *metadata, struct gl_shader_program *prog)
          unsigned vec_size =
             prog->data->UniformStorage[i].type->component_slots() *
             MAX2(prog->data->UniformStorage[i].array_elements, 1);
-         blob_write_bytes(metadata, prog->data->UniformStorage[i].storage,
+         unsigned slot =
+            prog->data->UniformStorage[i].storage -
+            prog->data->UniformDataSlots;
+         blob_write_bytes(metadata, &prog->data->UniformDataDefaults[slot],
                           sizeof(union gl_constant_value) * vec_size);
       }
    }
@@ -472,6 +475,9 @@ read_uniforms(struct blob_reader *metadata, struct gl_shader_program *prog)
    data = rzalloc_array(uniforms, union gl_constant_value,
                         prog->data->NumUniformDataSlots);
    prog->data->UniformDataSlots = data;
+   prog->data->UniformDataDefaults =
+      rzalloc_array(uniforms, union gl_constant_value,
+                    prog->data->NumUniformDataSlots);
 
    prog->UniformHash = new string_to_uint_map;
 
@@ -512,14 +518,20 @@ read_uniforms(struct blob_reader *metadata, struct gl_shader_program *prog)
          unsigned vec_size =
             prog->data->UniformStorage[i].type->component_slots() *
             MAX2(prog->data->UniformStorage[i].array_elements, 1);
+         unsigned slot =
+            prog->data->UniformStorage[i].storage -
+            prog->data->UniformDataSlots;
          blob_copy_bytes(metadata,
-                         (uint8_t *) prog->data->UniformStorage[i].storage,
+                         (uint8_t *) &prog->data->UniformDataSlots[slot],
                          sizeof(union gl_constant_value) * vec_size);
 
         assert(vec_size + prog->data->UniformStorage[i].storage <=
                data +  prog->data->NumUniformDataSlots);
       }
    }
+
+   memcpy(prog->data->UniformDataDefaults, prog->data->UniformDataSlots,
+          sizeof(union gl_constant_value) * prog->data->NumUniformDataSlots);
 }
 
 enum uniform_remap_type

src/mesa/main/mtypes.h

@@ -2886,6 +2886,17 @@ struct gl_shader_program_data
    unsigned NumUniformDataSlots;
    union gl_constant_value *UniformDataSlots;
 
+   /* Used to hold initial uniform values for program binary restores.
+    *
+    * From the ARB_get_program_binary spec:
+    *
+    *    "A successful call to ProgramBinary will reset all uniform
+    *    variables to their initial values. The initial value is either
+    *    the value of the variable's initializer as specified in the
+    *    original shader source, or 0 if no initializer was present.
+    */
+   union gl_constant_value *UniformDataDefaults;
+
    GLboolean Validated;
 
    /** List of all active resources after linking. */