+/**
+ * Get the variable that is being redeclared by this declaration
+ *
+ * Semantic checks to verify the validity of the redeclaration are also
+ * performed. If semantic checks fail, compilation error will be emitted via
+ * \c _mesa_glsl_error, but a non-\c NULL pointer will still be returned.
+ *
+ * \returns
+ * A pointer to an existing variable in the current scope if the declaration
+ * is a redeclaration, \c NULL otherwise.
+ */
+ir_variable *
+get_variable_being_redeclared(ir_variable *var, ast_declaration *decl,
+ struct _mesa_glsl_parse_state *state)
+{
+ /* Check if this declaration is actually a re-declaration, either to
+ * resize an array or add qualifiers to an existing variable.
+ *
+ * This is allowed for variables in the current scope, or when at
+ * global scope (for built-ins in the implicit outer scope).
+ */
+ ir_variable *earlier = state->symbols->get_variable(decl->identifier);
+ if (earlier == NULL ||
+ (state->current_function != NULL &&
+ !state->symbols->name_declared_this_scope(decl->identifier))) {
+ return NULL;
+ }
+
+
+ YYLTYPE loc = decl->get_location();
+
+ /* From page 24 (page 30 of the PDF) of the GLSL 1.50 spec,
+ *
+ * "It is legal to declare an array without a size and then
+ * later re-declare the same name as an array of the same
+ * type and specify a size."
+ */
+ if ((earlier->type->array_size() == 0)
+ && var->type->is_array()
+ && (var->type->element_type() == earlier->type->element_type())) {
+ /* FINISHME: This doesn't match the qualifiers on the two
+ * FINISHME: declarations. It's not 100% clear whether this is
+ * FINISHME: required or not.
+ */
+
+ /* From page 54 (page 60 of the PDF) of the GLSL 1.20 spec:
+ *
+ * "The size [of gl_TexCoord] can be at most
+ * gl_MaxTextureCoords."
+ */
+ const unsigned size = unsigned(var->type->array_size());
+ if ((strcmp("gl_TexCoord", var->name) == 0)
+ && (size > state->Const.MaxTextureCoords)) {
+ _mesa_glsl_error(& loc, state, "`gl_TexCoord' array size cannot "
+ "be larger than gl_MaxTextureCoords (%u)\n",
+ state->Const.MaxTextureCoords);
+ } else if ((size > 0) && (size <= earlier->max_array_access)) {
+ _mesa_glsl_error(& loc, state, "array size must be > %u due to "
+ "previous access",
+ earlier->max_array_access);
+ }
+
+ earlier->type = var->type;
+ delete var;
+ var = NULL;
+ } else if (state->ARB_fragment_coord_conventions_enable
+ && strcmp(var->name, "gl_FragCoord") == 0
+ && earlier->type == var->type
+ && earlier->mode == var->mode) {
+ /* Allow redeclaration of gl_FragCoord for ARB_fcc layout
+ * qualifiers.
+ */
+ earlier->origin_upper_left = var->origin_upper_left;
+ earlier->pixel_center_integer = var->pixel_center_integer;
+
+ /* According to section 4.3.7 of the GLSL 1.30 spec,
+ * the following built-in varaibles can be redeclared with an
+ * interpolation qualifier:
+ * * gl_FrontColor
+ * * gl_BackColor
+ * * gl_FrontSecondaryColor
+ * * gl_BackSecondaryColor
+ * * gl_Color
+ * * gl_SecondaryColor
+ */
+ } else if (state->language_version >= 130
+ && (strcmp(var->name, "gl_FrontColor") == 0
+ || strcmp(var->name, "gl_BackColor") == 0
+ || strcmp(var->name, "gl_FrontSecondaryColor") == 0
+ || strcmp(var->name, "gl_BackSecondaryColor") == 0
+ || strcmp(var->name, "gl_Color") == 0
+ || strcmp(var->name, "gl_SecondaryColor") == 0)
+ && earlier->type == var->type
+ && earlier->mode == var->mode) {
+ earlier->interpolation = var->interpolation;
+
+ /* Layout qualifiers for gl_FragDepth. */
+ } else if (state->AMD_conservative_depth_enable
+ && strcmp(var->name, "gl_FragDepth") == 0
+ && earlier->type == var->type
+ && earlier->mode == var->mode) {
+
+ /** From the AMD_conservative_depth spec:
+ * Within any shader, the first redeclarations of gl_FragDepth
+ * must appear before any use of gl_FragDepth.
+ */
+ if (earlier->used) {
+ _mesa_glsl_error(&loc, state,
+ "the first redeclaration of gl_FragDepth "
+ "must appear before any use of gl_FragDepth");
+ }
+
+ /* Prevent inconsistent redeclaration of depth layout qualifier. */
+ if (earlier->depth_layout != ir_depth_layout_none
+ && earlier->depth_layout != var->depth_layout) {
+ _mesa_glsl_error(&loc, state,
+ "gl_FragDepth: depth layout is declared here "
+ "as '%s, but it was previously declared as "
+ "'%s'",
+ depth_layout_string(var->depth_layout),
+ depth_layout_string(earlier->depth_layout));
+ }
+
+ earlier->depth_layout = var->depth_layout;
+
+ } else {
+ _mesa_glsl_error(&loc, state, "`%s' redeclared", decl->identifier);
+ }
+
+ return earlier;
+}
+
+/**
+ * Generate the IR for an initializer in a variable declaration
+ */
+ir_rvalue *
+process_initializer(ir_variable *var, ast_declaration *decl,
+ ast_fully_specified_type *type,
+ exec_list *initializer_instructions,
+ struct _mesa_glsl_parse_state *state)
+{
+ ir_rvalue *result = NULL;
+
+ YYLTYPE initializer_loc = decl->initializer->get_location();
+
+ /* From page 24 (page 30 of the PDF) of the GLSL 1.10 spec:
+ *
+ * "All uniform variables are read-only and are initialized either
+ * directly by an application via API commands, or indirectly by
+ * OpenGL."
+ */
+ if ((state->language_version <= 110)
+ && (var->mode == ir_var_uniform)) {
+ _mesa_glsl_error(& initializer_loc, state,
+ "cannot initialize uniforms in GLSL 1.10");
+ }
+
+ if (var->type->is_sampler()) {
+ _mesa_glsl_error(& initializer_loc, state,
+ "cannot initialize samplers");
+ }
+
+ if ((var->mode == ir_var_in) && (state->current_function == NULL)) {
+ _mesa_glsl_error(& initializer_loc, state,
+ "cannot initialize %s shader input / %s",
+ _mesa_glsl_shader_target_name(state->target),
+ (state->target == vertex_shader)
+ ? "attribute" : "varying");
+ }
+
+ ir_dereference *const lhs = new(state) ir_dereference_variable(var);
+ ir_rvalue *rhs = decl->initializer->hir(initializer_instructions,
+ state);
+
+ /* Calculate the constant value if this is a const or uniform
+ * declaration.
+ */
+ if (type->qualifier.flags.q.constant
+ || type->qualifier.flags.q.uniform) {
+ ir_rvalue *new_rhs = validate_assignment(state, var->type, rhs);
+ if (new_rhs != NULL) {
+ rhs = new_rhs;
+
+ ir_constant *constant_value = rhs->constant_expression_value();
+ if (!constant_value) {
+ _mesa_glsl_error(& initializer_loc, state,
+ "initializer of %s variable `%s' must be a "
+ "constant expression",
+ (type->qualifier.flags.q.constant)
+ ? "const" : "uniform",
+ decl->identifier);
+ if (var->type->is_numeric()) {
+ /* Reduce cascading errors. */
+ var->constant_value = ir_constant::zero(state, var->type);
+ }
+ } else {
+ rhs = constant_value;
+ var->constant_value = constant_value;
+ }
+ } else {
+ _mesa_glsl_error(&initializer_loc, state,
+ "initializer of type %s cannot be assigned to "
+ "variable of type %s",
+ rhs->type->name, var->type->name);
+ if (var->type->is_numeric()) {
+ /* Reduce cascading errors. */
+ var->constant_value = ir_constant::zero(state, var->type);
+ }
+ }
+ }
+
+ if (rhs && !rhs->type->is_error()) {
+ bool temp = var->read_only;
+ if (type->qualifier.flags.q.constant)
+ var->read_only = false;
+
+ /* Never emit code to initialize a uniform.
+ */
+ const glsl_type *initializer_type;
+ if (!type->qualifier.flags.q.uniform) {
+ result = do_assignment(initializer_instructions, state,
+ lhs, rhs,
+ type->get_location());
+ initializer_type = result->type;
+ } else
+ initializer_type = rhs->type;
+
+ /* If the declared variable is an unsized array, it must inherrit
+ * its full type from the initializer. A declaration such as
+ *
+ * uniform float a[] = float[](1.0, 2.0, 3.0, 3.0);
+ *
+ * becomes
+ *
+ * uniform float a[4] = float[](1.0, 2.0, 3.0, 3.0);
+ *
+ * The assignment generated in the if-statement (below) will also
+ * automatically handle this case for non-uniforms.
+ *
+ * If the declared variable is not an array, the types must
+ * already match exactly. As a result, the type assignment
+ * here can be done unconditionally. For non-uniforms the call
+ * to do_assignment can change the type of the initializer (via
+ * the implicit conversion rules). For uniforms the initializer
+ * must be a constant expression, and the type of that expression
+ * was validated above.
+ */
+ var->type = initializer_type;
+
+ var->read_only = temp;
+ }
+
+ return result;
+}