text: /*
   * Copyright © 2010 Intel Corporation
   *
   * Permission is hereby granted, free of charge, to any person obtaining a
   * copy of this software and associated documentation files (the "Software"),
   * to deal in the Software without restriction, including without limitation
   * the rights to use, copy, modify, merge, publish, distribute, sublicense,
   * and/or sell copies of the Software, and to permit persons to whom the
   * Software is furnished to do so, subject to the following conditions:
   *
   * The above copyright notice and this permission notice (including the next
   * paragraph) shall be included in all copies or substantial portions of the
   * Software.
   *
   * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
   * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
   * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
   * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
   * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
   * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
   * DEALINGS IN THE SOFTWARE.
   */
  
  #include "glsl_symbol_table.h"
  #include "ast.h"
  #include "glsl_types.h"
  #include "ir.h"
  #include "main/core.h" /* for MIN2 */
  
  static ir_rvalue *
  convert_component(ir_rvalue *src, const glsl_type *desired_type);
  
  bool
  apply_implicit_conversion(const glsl_type *to, ir_rvalue * &from,
                            struct _mesa_glsl_parse_state *state);
  
  static unsigned
  process_parameters(exec_list *instructions, exec_list *actual_parameters,
  		   exec_list *parameters,
  		   struct _mesa_glsl_parse_state *state)
  {
     unsigned count = 0;
  
     foreach_list (n, parameters) {
        ast_node *const ast = exec_node_data(ast_node, n, link);
        ir_rvalue *result = ast->hir(instructions, state);
  
        ir_constant *const constant = result->constant_expression_value();
        if (constant != NULL)
  	 result = constant;
  
        actual_parameters->push_tail(result);
        count++;
     }
  
     return count;
  }
  
  
  /**
   * Generate a source prototype for a function signature
   *
   * \param return_type Return type of the function.  May be \c NULL.
   * \param name        Name of the function.
   * \param parameters  List of \c ir_instruction nodes representing the
   *                    parameter list for the function.  This may be either a
   *                    formal (\c ir_variable) or actual (\c ir_rvalue)
   *                    parameter list.  Only the type is used.
   *
   * \return
   * A ralloced string representing the prototype of the function.
   */
  char *
  prototype_string(const glsl_type *return_type, const char *name,
  		 exec_list *parameters)
  {
     char *str = NULL;
  
     if (return_type != NULL)
        str = ralloc_asprintf(NULL, "%s ", return_type->name);
  
     ralloc_asprintf_append(&str, "%s(", name);
  
     const char *comma = "";
     foreach_list(node, parameters) {
        const ir_variable *const param = (ir_variable *) node;
  
        ralloc_asprintf_append(&str, "%s%s", comma, param->type->name);
        comma = ", ";
     }
  
     ralloc_strcat(&str, ")");
     return str;
  }
  
  
  static glsl_precision precision_for_call (const ir_function_signature* sig, glsl_precision max_prec, glsl_precision first_prec)
  {
  	if (sig->precision != glsl_precision_undefined)
  		return sig->precision;
  	
  	// if return type is boolean, treat as lowp
  	if (sig->return_type->base_type == GLSL_TYPE_BOOL)
  		return glsl_precision_low;
  	
  	// if it's a built-in texture function, precision comes from sampler (1st param) precision
  	if (sig->is_builtin)
  	{
  		if (strncmp (sig->function_name(), "texture", 7) == 0)
  			return first_prec;
  		if (strncmp (sig->function_name(), "shadow", 6) == 0)
  			return first_prec;
  	}
  	
  	// other built-in: max precision of parameters
  	if (sig->is_builtin)
  		return max_prec;
  	
  	// otherwise: undefined
  	return glsl_precision_undefined;	
  }
  
  
  static glsl_precision precision_for_call (const ir_function_signature* sig, exec_list *actual_parameters)
  {
  	glsl_precision prec_params_max = glsl_precision_undefined;
  	glsl_precision prec_params_first = glsl_precision_undefined;
  	int params_counter = 0;
  	
  	exec_list_iterator actual_iter = actual_parameters->iterator();
  	exec_list_iterator formal_iter = sig->parameters.iterator();
  	
  	while (actual_iter.has_next())
  	{
  		ir_rvalue *actual = (ir_rvalue *) actual_iter.get();
  		ir_variable *formal = (ir_variable *) formal_iter.get();
  		assert(actual != NULL);
  		assert(formal != NULL);
  		glsl_precision param_prec = (glsl_precision)formal->precision;
  		if (param_prec == glsl_precision_undefined)
  			param_prec = actual->get_precision();
  		prec_params_max = higher_precision (prec_params_max, param_prec);
  		if (params_counter == 0)
  			prec_params_first = param_prec;
  		
  		actual_iter.next();
  		formal_iter.next();
  		++params_counter;
  	}
  	
  	return precision_for_call (sig, prec_params_max, prec_params_first);
  }
  
  
  /**
   * Verify that 'out' and 'inout' actual parameters are lvalues.  Also, verify
   * that 'const_in' formal parameters (an extension in our IR) correspond to
   * ir_constant actual parameters.
   */
  static bool
  verify_parameter_modes(_mesa_glsl_parse_state *state,
  		       ir_function_signature *sig,
  		       exec_list &actual_ir_parameters,
  		       exec_list &actual_ast_parameters)
  {
     exec_node *actual_ir_node  = actual_ir_parameters.head;
     exec_node *actual_ast_node = actual_ast_parameters.head;
  
     foreach_list(formal_node, &sig->parameters) {
        /* The lists must be the same length. */
        assert(!actual_ir_node->is_tail_sentinel());
        assert(!actual_ast_node->is_tail_sentinel());
  
        const ir_variable *const formal = (ir_variable *) formal_node;
        const ir_rvalue *const actual = (ir_rvalue *) actual_ir_node;
        const ast_expression *const actual_ast =
  	 exec_node_data(ast_expression, actual_ast_node, link);
  
        /* FIXME: 'loc' is incorrect (as of 2011-01-21). It is always
         * FIXME: 0:0(0).
         */
        YYLTYPE loc = actual_ast->get_location();
  
        /* Verify that 'const_in' parameters are ir_constants. */
        if (formal->mode == ir_var_const_in &&
  	  actual->ir_type != ir_type_constant) {
  	 _mesa_glsl_error(&loc, state,
  			  "parameter `in %s' must be a constant expression",
  			  formal->name);
  	 return false;
        }
  
        /* Verify that 'out' and 'inout' actual parameters are lvalues. */
        if (formal->mode == ir_var_out || formal->mode == ir_var_inout) {
  	 const char *mode = NULL;
  	 switch (formal->mode) {
  	 case ir_var_out:   mode = "out";   break;
  	 case ir_var_inout: mode = "inout"; break;
  	 default:           assert(false);  break;
  	 }
  
  	 /* This AST-based check catches errors like f(i++).  The IR-based
  	  * is_lvalue() is insufficient because the actual parameter at the
  	  * IR-level is just a temporary value, which is an l-value.
  	  */
  	 if (actual_ast->non_lvalue_description != NULL) {
  	    _mesa_glsl_error(&loc, state,
  			     "function parameter '%s %s' references a %s",
  			     mode, formal->name,
  			     actual_ast->non_lvalue_description);
  	    return false;
  	 }
  
  	 ir_variable *var = actual->variable_referenced();
  	 if (var)
  	    var->assigned = true;
  
  	 if (var && var->read_only) {
  	    _mesa_glsl_error(&loc, state,
  			     "function parameter '%s %s' references the "
  			     "read-only variable '%s'",
  			     mode, formal->name,
  			     actual->variable_referenced()->name);
  	    return false;
  	 } else if (!actual->is_lvalue()) {
  	    _mesa_glsl_error(&loc, state,
  			     "function parameter '%s %s' is not an lvalue",
  			     mode, formal->name);
  	    return false;
  	 }
        }
  
        actual_ir_node  = actual_ir_node->next;
        actual_ast_node = actual_ast_node->next;
     }
     return true;
  }
  
  /**
   * If a function call is generated, \c call_ir will point to it on exit.
   * Otherwise \c call_ir will be set to \c NULL.
   */
  static ir_rvalue *
  generate_call(exec_list *instructions, ir_function_signature *sig,
  	      YYLTYPE *loc, exec_list *actual_parameters,
  	      ir_call **call_ir,
  	      struct _mesa_glsl_parse_state *state)
  {
     void *ctx = state;
     exec_list post_call_conversions;
  
     *call_ir = NULL;
  
     /* Perform implicit conversion of arguments.  For out parameters, we need
      * to place them in a temporary variable and do the conversion after the
      * call takes place.  Since we haven't emitted the call yet, we'll place
      * the post-call conversions in a temporary exec_list, and emit them later.
      */
     exec_list_iterator actual_iter = actual_parameters->iterator();
     exec_list_iterator formal_iter = sig->parameters.iterator();
  
     while (actual_iter.has_next()) {
        ir_rvalue *actual = (ir_rvalue *) actual_iter.get();
        ir_variable *formal = (ir_variable *) formal_iter.get();
  
        assert(actual != NULL);
        assert(formal != NULL);
  
        if (formal->type->is_numeric() || formal->type->is_boolean()) {
  	 switch (formal->mode) {
  	 case ir_var_const_in:
  	 case ir_var_in: {
  	    ir_rvalue *converted
  	       = convert_component(actual, formal->type);
  	    actual->replace_with(converted);
  	    break;
  	 }
  	 case ir_var_out:
  	    if (actual->type != formal->type) {
  	       /* To convert an out parameter, we need to create a
  		* temporary variable to hold the value before conversion,
  		* and then perform the conversion after the function call
  		* returns.
  		*
  		* This has the effect of transforming code like this:
  		*
  		*   void f(out int x);
  		*   float value;
  		*   f(value);
  		*
  		* Into IR that's equivalent to this:
  		*
  		*   void f(out int x);
  		*   float value;
  		*   int out_parameter_conversion;
  		*   f(out_parameter_conversion);
  		*   value = float(out_parameter_conversion);
  		*/
  	       ir_variable *tmp =
  		  new(ctx) ir_variable(formal->type,
  				       "out_parameter_conversion",
  				       ir_var_temporary, precision_for_call(sig,actual_parameters));
  	       instructions->push_tail(tmp);
  	       ir_dereference_variable *deref_tmp_1
  		  = new(ctx) ir_dereference_variable(tmp);
  	       ir_dereference_variable *deref_tmp_2
  		  = new(ctx) ir_dereference_variable(tmp);
  	       ir_rvalue *converted_tmp
  		  = convert_component(deref_tmp_1, actual->type);
  	       ir_assignment *assignment
  		  = new(ctx) ir_assignment(actual, converted_tmp);
  	       post_call_conversions.push_tail(assignment);
  	       actual->replace_with(deref_tmp_2);
  	    }
  	    break;
  	 case ir_var_inout:
  	    /* Inout parameters should never require conversion, since that
  	     * would require an implicit conversion to exist both to and
  	     * from the formal parameter type, and there are no
  	     * bidirectional implicit conversions.
  	     */
  	    assert (actual->type == formal->type);
  	    break;
  	 default:
  	    assert (!"Illegal formal parameter mode");
  	    break;
  	 }
        }
  
        actual_iter.next();
        formal_iter.next();
     }
  
     /* If the function call is a constant expression, don't generate any
      * instructions; just generate an ir_constant.
      *
      * Function calls were first allowed to be constant expressions in GLSL 1.20.
      */
     if (state->language_version >= 120) {
        ir_constant *value = sig->constant_expression_value(actual_parameters, NULL);
        if (value != NULL) {
  	 return value;
        }
     }
  
     ir_dereference_variable *deref = NULL;
     if (!sig->return_type->is_void()) {
        /* Create a new temporary to hold the return value. */
        ir_variable *var;
  
        var = new(ctx) ir_variable(sig->return_type,
  				 ralloc_asprintf(ctx, "%s_retval",
  						 sig->function_name()),
  				 ir_var_temporary, precision_for_call(sig,actual_parameters));
        instructions->push_tail(var);
  
        deref = new(ctx) ir_dereference_variable(var);
     }
     ir_call *call = new(ctx) ir_call(sig, deref, actual_parameters);
     instructions->push_tail(call);
  
     /* Also emit any necessary out-parameter conversions. */
     instructions->append_list(&post_call_conversions);
  
     return deref ? deref->clone(ctx, NULL) : NULL;
  }
  
  /**
   * Given a function name and parameter list, find the matching signature.
   */
  static ir_function_signature *
  match_function_by_name(const char *name,
  		       exec_list *actual_parameters,
  		       struct _mesa_glsl_parse_state *state)
  {
     void *ctx = state;
     ir_function *f = state->symbols->get_function(name);
     ir_function_signature *local_sig = NULL;
     ir_function_signature *sig = NULL;
  
     /* Is the function hidden by a record type constructor? */
     if (state->symbols->get_type(name))
        goto done; /* no match */
  
     /* Is the function hidden by a variable (impossible in 1.10)? */
     if (state->language_version != 110 && state->symbols->get_variable(name))
        goto done; /* no match */
  
     if (f != NULL) {
        /* Look for a match in the local shader.  If exact, we're done. */
        bool is_exact = false;
        sig = local_sig = f->matching_signature(actual_parameters, &is_exact);
        if (is_exact)
  	 goto done;
  
        if (!state->es_shader && f->has_user_signature()) {
  	 /* In desktop GL, the presence of a user-defined signature hides any
  	  * built-in signatures, so we must ignore them.  In contrast, in ES2
  	  * user-defined signatures add new overloads, so we must proceed.
  	  */
  	 goto done;
        }
     }
  
     /* Local shader has no exact candidates; check the built-ins. */
     _mesa_glsl_initialize_functions(state);
     for (unsigned i = 0; i < state->num_builtins_to_link; i++) {
        ir_function *builtin =
  	 state->builtins_to_link[i]->symbols->get_function(name);
        if (builtin == NULL)
  	 continue;
  
        bool is_exact = false;
        ir_function_signature *builtin_sig =
  	 builtin->matching_signature(actual_parameters, &is_exact);
  
        if (builtin_sig == NULL)
  	 continue;
  
        /* If the built-in signature is exact, we can stop. */
        if (is_exact) {
  	 sig = builtin_sig;
  	 goto done;
        }
  
        if (sig == NULL) {
  	 /* We found an inexact match, which is better than nothing.  However,
  	  * we should keep searching for an exact match.
  	  */
  	 sig = builtin_sig;
        }
     }
  
  done:
     if (sig != NULL) {
        /* If the match is from a linked built-in shader, import the prototype. */
        if (sig != local_sig) {
  	 if (f == NULL) {
  	    f = new(ctx) ir_function(name);
  	    state->symbols->add_global_function(f);
  	    emit_function(state, f);
  	 }
  	 f->add_signature(sig->clone_prototype(f, NULL));
        }
     }
     return sig;
  }
  
  /**
   * Raise a "no matching function" error, listing all possible overloads the
   * compiler considered so developers can figure out what went wrong.
   */
  static void
  no_matching_function_error(const char *name,
  			   YYLTYPE *loc,
  			   exec_list *actual_parameters,
  			   _mesa_glsl_parse_state *state)
  {
     char *str = prototype_string(NULL, name, actual_parameters);
     _mesa_glsl_error(loc, state, "no matching function for call to `%s'", str);
     ralloc_free(str);
  
     const char *prefix = "candidates are: ";
  
     for (int i = -1; i < (int) state->num_builtins_to_link; i++) {
        glsl_symbol_table *syms = i >= 0 ? state->builtins_to_link[i]->symbols
  				       : state->symbols;
        ir_function *f = syms->get_function(name);
        if (f == NULL)
  	 continue;
  
        foreach_list (node, &f->signatures) {
  	 ir_function_signature *sig = (ir_function_signature *) node;
  
  	 str = prototype_string(sig->return_type, f->name, &sig->parameters);
  	 _mesa_glsl_error(loc, state, "%s%s", prefix, str);
  	 ralloc_free(str);
  
  	 prefix = "                ";
        }
     }
  }
  
  /**
   * Perform automatic type conversion of constructor parameters
   *
   * This implements the rules in the "Conversion and Scalar Constructors"
   * section (GLSL 1.10 section 5.4.1), not the "Implicit Conversions" rules.
   */
  static ir_rvalue *
  convert_component(ir_rvalue *src, const glsl_type *desired_type)
  {
     void *ctx = ralloc_parent(src);
     const unsigned a = desired_type->base_type;
     const unsigned b = src->type->base_type;
     ir_expression *result = NULL;
  
     if (src->type->is_error())
        return src;
  
     assert(a <= GLSL_TYPE_BOOL);
     assert(b <= GLSL_TYPE_BOOL);
  
     if (a == b)
        return src;
  
     switch (a) {
     case GLSL_TYPE_UINT:
        switch (b) {
        case GLSL_TYPE_INT:
  	 result = new(ctx) ir_expression(ir_unop_i2u, src);
  	 break;
        case GLSL_TYPE_FLOAT:
  	 result = new(ctx) ir_expression(ir_unop_f2u, src);
  	 break;
        case GLSL_TYPE_BOOL:
  	 result = new(ctx) ir_expression(ir_unop_i2u,
  		  new(ctx) ir_expression(ir_unop_b2i, src));
  	 break;
        }
        break;
     case GLSL_TYPE_INT:
        switch (b) {
        case GLSL_TYPE_UINT:
  	 result = new(ctx) ir_expression(ir_unop_u2i, src);
  	 break;
        case GLSL_TYPE_FLOAT:
  	 result = new(ctx) ir_expression(ir_unop_f2i, src);
  	 break;
        case GLSL_TYPE_BOOL:
  	 result = new(ctx) ir_expression(ir_unop_b2i, src);
  	 break;
        }
        break;
     case GLSL_TYPE_FLOAT:
        switch (b) {
        case GLSL_TYPE_UINT:
  	 result = new(ctx) ir_expression(ir_unop_u2f, desired_type, src, NULL);
  	 break;
        case GLSL_TYPE_INT:
  	 result = new(ctx) ir_expression(ir_unop_i2f, desired_type, src, NULL);
  	 break;
        case GLSL_TYPE_BOOL:
  	 result = new(ctx) ir_expression(ir_unop_b2f, desired_type, src, NULL);
  	 break;
        }
        break;
     case GLSL_TYPE_BOOL:
        switch (b) {
        case GLSL_TYPE_UINT:
  	 result = new(ctx) ir_expression(ir_unop_i2b,
  		  new(ctx) ir_expression(ir_unop_u2i, src));
  	 break;
        case GLSL_TYPE_INT:
  	 result = new(ctx) ir_expression(ir_unop_i2b, desired_type, src, NULL);
  	 break;
        case GLSL_TYPE_FLOAT:
  	 result = new(ctx) ir_expression(ir_unop_f2b, desired_type, src, NULL);
  	 break;
        }
        break;
     }
  
     assert(result != NULL);
     assert(result->type == desired_type);
  
     /* Try constant folding; it may fold in the conversion we just added. */
     ir_constant *const constant = result->constant_expression_value();
     return (constant != NULL) ? (ir_rvalue *) constant : (ir_rvalue *) result;
  }
  
  /**
   * Dereference a specific component from a scalar, vector, or matrix
   */
  static ir_rvalue *
  dereference_component(ir_rvalue *src, unsigned component)
  {
     void *ctx = ralloc_parent(src);
     assert(component < src->type->components());
  
     /* If the source is a constant, just create a new constant instead of a
      * dereference of the existing constant.
      */
     ir_constant *constant = src->as_constant();
     if (constant)
        return new(ctx) ir_constant(constant, component);
  
     if (src->type->is_scalar()) {
        return src;
     } else if (src->type->is_vector()) {
        return new(ctx) ir_swizzle(src, component, 0, 0, 0, 1);
     } else {
        assert(src->type->is_matrix());
  
        /* Dereference a row of the matrix, then call this function again to get
         * a specific element from that row.
         */
        const int c = component / src->type->column_type()->vector_elements;
        const int r = component % src->type->column_type()->vector_elements;
        ir_constant *const col_index = new(ctx) ir_constant(c);
        ir_dereference *const col = new(ctx) ir_dereference_array(src, col_index);
  
        col->type = src->type->column_type();
  
        return dereference_component(col, r);
     }
  
     assert(!"Should not get here.");
     return NULL;
  }
  
  
  static ir_rvalue *
  process_array_constructor(exec_list *instructions,
  			  const glsl_type *constructor_type,
  			  YYLTYPE *loc, exec_list *parameters,
  			  struct _mesa_glsl_parse_state *state)
  {
     void *ctx = state;
     /* Array constructors come in two forms: sized and unsized.  Sized array
      * constructors look like 'vec4[2](a, b)', where 'a' and 'b' are vec4
      * variables.  In this case the number of parameters must exactly match the
      * specified size of the array.
      *
      * Unsized array constructors look like 'vec4[](a, b)', where 'a' and 'b'
      * are vec4 variables.  In this case the size of the array being constructed
      * is determined by the number of parameters.
      *
      * From page 52 (page 58 of the PDF) of the GLSL 1.50 spec:
      *
      *    "There must be exactly the same number of arguments as the size of
      *    the array being constructed. If no size is present in the
      *    constructor, then the array is explicitly sized to the number of
      *    arguments provided. The arguments are assigned in order, starting at
      *    element 0, to the elements of the constructed array. Each argument
      *    must be the same type as the element type of the array, or be a type
      *    that can be converted to the element type of the array according to
      *    Section 4.1.10 "Implicit Conversions.""
      */
     exec_list actual_parameters;
     const unsigned parameter_count =
        process_parameters(instructions, &actual_parameters, parameters, state);
  
     if ((parameter_count == 0)
         || ((constructor_type->length != 0)
  	   && (constructor_type->length != parameter_count))) {
        const unsigned min_param = (constructor_type->length == 0)
  	 ? 1 : constructor_type->length;
  
        _mesa_glsl_error(loc, state, "array constructor must have %s %u "
  		       "parameter%s",
  		       (constructor_type->length != 0) ? "at least" : "exactly",
  		       min_param, (min_param <= 1) ? "" : "s");
        return ir_rvalue::error_value(ctx);
     }
  
     if (constructor_type->length == 0) {
        constructor_type =
  	 glsl_type::get_array_instance(constructor_type->element_type(),
  				       parameter_count);
        assert(constructor_type != NULL);
        assert(constructor_type->length == parameter_count);
     }
  
     bool all_parameters_are_constant = true;
  
     /* Type cast each parameter and, if possible, fold constants. */
     foreach_list_safe(n, &actual_parameters) {
        ir_rvalue *ir = (ir_rvalue *) n;
        ir_rvalue *result = ir;
  
        /* Apply implicit conversions (not the scalar constructor rules!). See
         * the spec quote above. */
        if (constructor_type->element_type()->is_float()) {
  	 const glsl_type *desired_type =
  	    glsl_type::get_instance(GLSL_TYPE_FLOAT,
  				    ir->type->vector_elements,
  				    ir->type->matrix_columns);
  	 if (result->type->can_implicitly_convert_to(desired_type)) {
  	    /* Even though convert_component() implements the constructor
  	     * conversion rules (not the implicit conversion rules), its safe
  	     * to use it here because we already checked that the implicit
  	     * conversion is legal.
  	     */
  	    result = convert_component(ir, desired_type);
  	 }
        }
  
        if (result->type != constructor_type->element_type()) {
  	 _mesa_glsl_error(loc, state, "type error in array constructor: "
  			  "expected: %s, found %s",
  			  constructor_type->element_type()->name,
  			  result->type->name);
        }
  
        /* Attempt to convert the parameter to a constant valued expression.
         * After doing so, track whether or not all the parameters to the
         * constructor are trivially constant valued expressions.
         */
        ir_rvalue *const constant = result->constant_expression_value();
  
        if (constant != NULL)
           result = constant;
        else
           all_parameters_are_constant = false;
  
        ir->replace_with(result);
     }
  
     if (all_parameters_are_constant)
        return new(ctx) ir_constant(constructor_type, &actual_parameters);
  
     ir_variable *var = new(ctx) ir_variable(constructor_type, "array_ctor",
  					   ir_var_temporary, glsl_precision_undefined);
     instructions->push_tail(var);
  
     int i = 0;
     foreach_list(node, &actual_parameters) {
        ir_rvalue *rhs = (ir_rvalue *) node;
        ir_rvalue *lhs = new(ctx) ir_dereference_array(var,
  						     new(ctx) ir_constant(i));
  
        ir_instruction *assignment = new(ctx) ir_assignment(lhs, rhs, NULL);
        instructions->push_tail(assignment);
  
        i++;
     }
  
     return new(ctx) ir_dereference_variable(var);
  }
  
  
  /**
   * Try to convert a record constructor to a constant expression
   */
  static ir_constant *
  constant_record_constructor(const glsl_type *constructor_type,
  			    exec_list *parameters, void *mem_ctx)
  {
     foreach_list(node, parameters) {
        ir_constant *constant = ((ir_instruction *) node)->as_constant();
        if (constant == NULL)
  	 return NULL;
        node->replace_with(constant);
     }
  
     return new(mem_ctx) ir_constant(constructor_type, parameters);
  }
  
  
  /**
   * Determine if a list consists of a single scalar r-value
   */
  bool
  single_scalar_parameter(exec_list *parameters)
  {
     const ir_rvalue *const p = (ir_rvalue *) parameters->head;
     assert(((ir_rvalue *)p)->as_rvalue() != NULL);
  
     return (p->type->is_scalar() && p->next->is_tail_sentinel());
  }
  
  
  /**
   * Generate inline code for a vector constructor
   *
   * The generated constructor code will consist of a temporary variable
   * declaration of the same type as the constructor.  A sequence of assignments
   * from constructor parameters to the temporary will follow.
   *
   * \return
   * An \c ir_dereference_variable of the temprorary generated in the constructor
   * body.
   */
  ir_rvalue *
  emit_inline_vector_constructor(const glsl_type *type, unsigned ast_precision,
  			       exec_list *instructions,
  			       exec_list *parameters,
  			       void *ctx)
  {
     assert(!parameters->is_empty());
  
     ir_variable *var = new(ctx) ir_variable(type, "vec_ctor", ir_var_temporary, (glsl_precision)ast_precision);
     instructions->push_tail(var);
  
     /* There are two kinds of vector constructors.
      *
      *  - Construct a vector from a single scalar by replicating that scalar to
      *    all components of the vector.
      *
      *  - Construct a vector from an arbirary combination of vectors and
      *    scalars.  The components of the constructor parameters are assigned
      *    to the vector in order until the vector is full.
      */
     const unsigned lhs_components = type->components();
     if (single_scalar_parameter(parameters)) {
        ir_rvalue *first_param = (ir_rvalue *)parameters->head;
        ir_rvalue *rhs = new(ctx) ir_swizzle(first_param, 0, 0, 0, 0,
  					   lhs_components);
        var->precision = higher_precision ((glsl_precision)var->precision, rhs->get_precision());
        ir_dereference_variable *lhs = new(ctx) ir_dereference_variable(var);
        const unsigned mask = (1U << lhs_components) - 1;
  
        assert(rhs->type == lhs->type);
  
        ir_instruction *inst = new(ctx) ir_assignment(lhs, rhs, NULL, mask);
        instructions->push_tail(inst);
     } else {
        unsigned base_component = 0;
        unsigned base_lhs_component = 0;
        ir_constant_data data;
        unsigned constant_mask = 0, constant_components = 0;
  
        memset(&data, 0, sizeof(data));
  
        foreach_list(node, parameters) {
  	 ir_rvalue *param = (ir_rvalue *) node;
  	 var->precision = higher_precision ((glsl_precision)var->precision, param->get_precision());
  	 unsigned rhs_components = param->type->components();
  
  	 /* Do not try to assign more components to the vector than it has!
  	  */
  	 if ((rhs_components + base_lhs_component) > lhs_components) {
  	    rhs_components = lhs_components - base_lhs_component;
  	 }
  
  	 const ir_constant *const c = param->as_constant();
  	 if (c != NULL) {
  	    for (unsigned i = 0; i < rhs_components; i++) {
  	       switch (c->type->base_type) {
  	       case GLSL_TYPE_UINT:
  		  data.u[i + base_component] = c->get_uint_component(i);
  		  break;
  	       case GLSL_TYPE_INT:
  		  data.i[i + base_component] = c->get_int_component(i);
  		  break;
  	       case GLSL_TYPE_FLOAT:
  		  data.f[i + base_component] = c->get_float_component(i);
  		  break;
  	       case GLSL_TYPE_BOOL:
  		  data.b[i + base_component] = c->get_bool_component(i);
  		  break;
  	       default:
  		  assert(!"Should not get here.");
  		  break;
  	       }
  	    }
  
  	    /* Mask of fields to be written in the assignment.
  	     */
  	    constant_mask |= ((1U << rhs_components) - 1) << base_lhs_component;
  	    constant_components += rhs_components;
  
  	    base_component += rhs_components;
  	 }
  	 /* Advance the component index by the number of components
  	  * that were just assigned.
  	  */
  	 base_lhs_component += rhs_components;
        }
  
        if (constant_mask != 0) {
  	 ir_dereference *lhs = new(ctx) ir_dereference_variable(var);
  	 const glsl_type *rhs_type = glsl_type::get_instance(var->type->base_type,
  							     constant_components,
  							     1);
  	 ir_rvalue *rhs = new(ctx) ir_constant(rhs_type, &data);
  
  	 ir_instruction *inst =
  	    new(ctx) ir_assignment(lhs, rhs, NULL, constant_mask);
  	 instructions->push_tail(inst);
        }
  
        base_component = 0;
        foreach_list(node, parameters) {
  	 ir_rvalue *param = (ir_rvalue *) node;
  	 unsigned rhs_components = param->type->components();
  
  	 /* Do not try to assign more components to the vector than it has!
  	  */
  	 if ((rhs_components + base_component) > lhs_components) {
  	    rhs_components = lhs_components - base_component;
  	 }
  
  	 const ir_constant *const c = param->as_constant();
  	 if (c == NULL) {
  	    /* Mask of fields to be written in the assignment.
  	     */
  	    const unsigned write_mask = ((1U << rhs_components) - 1)
  	       << base_component;
  
  	    ir_dereference *lhs = new(ctx) ir_dereference_variable(var);
  
  	    /* Generate a swizzle so that LHS and RHS sizes match.
  	     */
  	    ir_rvalue *rhs =
  	       new(ctx) ir_swizzle(param, 0, 1, 2, 3, rhs_components);
  
  	    ir_instruction *inst =
  	       new(ctx) ir_assignment(lhs, rhs, NULL, write_mask);
  	    instructions->push_tail(inst);
  	 }
  
  	 /* Advance the component index by the number of components that were
  	  * just assigned.
  	  */
  	 base_component += rhs_components;
        }
     }
     return new(ctx) ir_dereference_variable(var);
  }
  
  
  /**
   * Generate assignment of a portion of a vector to a portion of a matrix column
   *
   * \param src_base  First component of the source to be used in assignment
   * \param column    Column of destination to be assiged
   * \param row_base  First component of the destination column to be assigned
   * \param count     Number of components to be assigned
   *
   * \note
   * \c src_base + \c count must be less than or equal to the number of components
   * in the source vector.
   */
  ir_instruction *
  assign_to_matrix_column(ir_variable *var, unsigned column, unsigned row_base,
  			ir_rvalue *src, unsigned src_base, unsigned count,
  			void *mem_ctx)
  {
     ir_constant *col_idx = new(mem_ctx) ir_constant(column);
     ir_dereference *column_ref = new(mem_ctx) ir_dereference_array(var, col_idx);
  
     assert(column_ref->type->components() >= (row_base + count));
     assert(src->type->components() >= (src_base + count));
  
     /* Generate a swizzle that extracts the number of components from the source
      * that are to be assigned to the column of the matrix.
      */
     if (count < src->type->vector_elements) {
        src = new(mem_ctx) ir_swizzle(src,
  				    src_base + 0, src_base + 1,
  				    src_base + 2, src_base + 3,
  				    count);
     }
  
     /* Mask of fields to be written in the assignment.
      */
     const unsigned write_mask = ((1U << count) - 1) << row_base;
  
     return new(mem_ctx) ir_assignment(column_ref, src, NULL, write_mask);
  }
  
  
  /**
   * Generate inline code for a matrix constructor
   *
   * The generated constructor code will consist of a temporary variable
   * declaration of the same type as the constructor.  A sequence of assignments
   * from constructor parameters to the temporary will follow.
   *
   * \return
   * An \c ir_dereference_variable of the temprorary generated in the constructor
   * body.
   */
  ir_rvalue *
  emit_inline_matrix_constructor(const glsl_type *type, int ast_precision,
  			       exec_list *instructions,
  			       exec_list *parameters,
  			       void *ctx)
  {
     assert(!parameters->is_empty());
  
     ir_variable *var = new(ctx) ir_variable(type, "mat_ctor", ir_var_temporary, (glsl_precision)ast_precision);
     instructions->push_tail(var);
  
     /* There are three kinds of matrix constructors.
      *
      *  - Construct a matrix from a single scalar by replicating that scalar to
      *    along the diagonal of the matrix and setting all other components to
      *    zero.
      *
      *  - Construct a matrix from an arbirary combination of vectors and
      *    scalars.  The components of the constructor parameters are assigned
      *    to the matrix in colum-major order until the matrix is full.
      *
      *  - Construct a matrix from a single matrix.  The source matrix is copied
      *    to the upper left portion of the constructed matrix, and the remaining
      *    elements take values from the identity matrix.
      */
     ir_rvalue *const first_param = (ir_rvalue *) parameters->head;
     if (single_scalar_parameter(parameters)) {
        /* Assign the scalar to the X component of a vec4, and fill the remaining
         * components with zero.
         */
        ir_variable *rhs_var =
  	 new(ctx) ir_variable(glsl_type::vec4_type, "mat_ctor_vec",
  			      ir_var_temporary, (glsl_precision)ast_precision);
        instructions->push_tail(rhs_var);
  
        ir_constant_data zero;
        zero.f[0] = 0.0;
        zero.f[1] = 0.0;
        zero.f[2] = 0.0;
        zero.f[3] = 0.0;
  
        ir_instruction *inst =
  	 new(ctx) ir_assignment(new(ctx) ir_dereference_variable(rhs_var),
  				new(ctx) ir_constant(rhs_var->type, &zero),
  				NULL);
        instructions->push_tail(inst);
  
        ir_dereference *const rhs_ref = new(ctx) ir_dereference_variable(rhs_var);
  
        inst = new(ctx) ir_assignment(rhs_ref, first_param, NULL, 0x01);
        instructions->push_tail(inst);
  
        /* Assign the temporary vector to each column of the destination matrix
         * with a swizzle that puts the X component on the diagonal of the
         * matrix.  In some cases this may mean that the X component does not
         * get assigned into the column at all (i.e., when the matrix has more
         * columns than rows).
         */
        static const unsigned rhs_swiz[4][4] = {
  	 { 0, 1, 1, 1 },
  	 { 1, 0, 1, 1 },
  	 { 1, 1, 0, 1 },
  	 { 1, 1, 1, 0 }
        };
  
        const unsigned cols_to_init = MIN2(type->matrix_columns,
  					 type->vector_elements);
        for (unsigned i = 0; i < cols_to_init; i++) {
  	 ir_constant *const col_idx = new(ctx) ir_constant(i);
  	 ir_rvalue *const col_ref = new(ctx) ir_dereference_array(var, col_idx);
  
  	 ir_rvalue *const rhs_ref = new(ctx) ir_dereference_variable(rhs_var);
  	 ir_rvalue *const rhs = new(ctx) ir_swizzle(rhs_ref, rhs_swiz[i],
  						    type->vector_elements);
  
  	 inst = new(ctx) ir_assignment(col_ref, rhs, NULL);
  	 instructions->push_tail(inst);
        }
  
        for (unsigned i = cols_to_init; i < type->matrix_columns; i++) {
  	 ir_constant *const col_idx = new(ctx) ir_constant(i);
  	 ir_rvalue *const col_ref = new(ctx) ir_dereference_array(var, col_idx);
  
  	 ir_rvalue *const rhs_ref = new(ctx) ir_dereference_variable(rhs_var);
  	 ir_rvalue *const rhs = new(ctx) ir_swizzle(rhs_ref, 1, 1, 1, 1,
  						    type->vector_elements);
  
  	 inst = new(ctx) ir_assignment(col_ref, rhs, NULL);
  	 instructions->push_tail(inst);
        }
     } else if (first_param->type->is_matrix()) {
        /* From page 50 (56 of the PDF) of the GLSL 1.50 spec:
         *
         *     "If a matrix is constructed from a matrix, then each component
         *     (column i, row j) in the result that has a corresponding
         *     component (column i, row j) in the argument will be initialized
         *     from there. All other components will be initialized to the
         *     identity matrix. If a matrix argument is given to a matrix
         *     constructor, it is an error to have any other arguments."
         */
        assert(first_param->next->is_tail_sentinel());
        ir_rvalue *const src_matrix = first_param;
  
        /* If the source matrix is smaller, pre-initialize the relavent parts of
         * the destination matrix to the identity matrix.
         */
        if ((src_matrix->type->matrix_columns < var->type->matrix_columns)
  	  || (src_matrix->type->vector_elements < var->type->vector_elements)) {
  
  	 /* If the source matrix has fewer rows, every column of the destination
  	  * must be initialized.  Otherwise only the columns in the destination
  	  * that do not exist in the source must be initialized.
  	  */
  	 unsigned col =
  	    (src_matrix->type->vector_elements < var->type->vector_elements)
  	    ? 0 : src_matrix->type->matrix_columns;
  
  	 const glsl_type *const col_type = var->type->column_type();
  	 for (/* empty */; col < var->type->matrix_columns; col++) {
  	    ir_constant_data ident;
  
  	    ident.f[0] = 0.0;
  	    ident.f[1] = 0.0;
  	    ident.f[2] = 0.0;
  	    ident.f[3] = 0.0;
  
  	    ident.f[col] = 1.0;
  
  	    ir_rvalue *const rhs = new(ctx) ir_constant(col_type, &ident);
  
  	    ir_rvalue *const lhs =
  	       new(ctx) ir_dereference_array(var, new(ctx) ir_constant(col));
  
  	    ir_instruction *inst = new(ctx) ir_assignment(lhs, rhs, NULL);
  	    instructions->push_tail(inst);
  	 }
        }
  
        /* Assign columns from the source matrix to the destination matrix.
         *
         * Since the parameter will be used in the RHS of multiple assignments,
         * generate a temporary and copy the paramter there.
         */
        ir_variable *const rhs_var =
  	 new(ctx) ir_variable(first_param->type, "mat_ctor_mat",
  			      ir_var_temporary, (glsl_precision)ast_precision);
        instructions->push_tail(rhs_var);
  
        ir_dereference *const rhs_var_ref =
  	 new(ctx) ir_dereference_variable(rhs_var);
        ir_instruction *const inst =
  	 new(ctx) ir_assignment(rhs_var_ref, first_param, NULL);
        instructions->push_tail(inst);
  
        const unsigned last_row = MIN2(src_matrix->type->vector_elements,
  				     var->type->vector_elements);
        const unsigned last_col = MIN2(src_matrix->type->matrix_columns,
  				     var->type->matrix_columns);
  
        unsigned swiz[4] = { 0, 0, 0, 0 };
        for (unsigned i = 1; i < last_row; i++)
  	 swiz[i] = i;
  
        const unsigned write_mask = (1U << last_row) - 1;
  
        for (unsigned i = 0; i < last_col; i++) {
  	 ir_dereference *const lhs =
  	    new(ctx) ir_dereference_array(var, new(ctx) ir_constant(i));
  	 ir_rvalue *const rhs_col =
  	    new(ctx) ir_dereference_array(rhs_var, new(ctx) ir_constant(i));
  
  	 /* If one matrix has columns that are smaller than the columns of the
  	  * other matrix, wrap the column access of the larger with a swizzle
  	  * so that the LHS and RHS of the assignment have the same size (and
  	  * therefore have the same type).
  	  *
  	  * It would be perfectly valid to unconditionally generate the
  	  * swizzles, this this will typically result in a more compact IR tree.
  	  */
  	 ir_rvalue *rhs;
  	 if (lhs->type->vector_elements != rhs_col->type->vector_elements) {
  	    rhs = new(ctx) ir_swizzle(rhs_col, swiz, last_row);
  	 } else {
  	    rhs = rhs_col;
  	 }
  
  	 ir_instruction *inst =
  	    new(ctx) ir_assignment(lhs, rhs, NULL, write_mask);
  	 instructions->push_tail(inst);
        }
     } else {
        const unsigned cols = type->matrix_columns;
        const unsigned rows = type->vector_elements;
        unsigned col_idx = 0;
        unsigned row_idx = 0;
  
        foreach_list (node, parameters) {
  	 ir_rvalue *const rhs = (ir_rvalue *) node;
  	 const unsigned components_remaining_this_column = rows - row_idx;
  	 unsigned rhs_components = rhs->type->components();
  	 unsigned rhs_base = 0;
  
  	 /* Since the parameter might be used in the RHS of two assignments,
  	  * generate a temporary and copy the paramter there.
  	  */
  	 ir_variable *rhs_var =
  	    new(ctx) ir_variable(rhs->type, "mat_ctor_vec", ir_var_temporary, (glsl_precision)ast_precision);
  	 instructions->push_tail(rhs_var);
  
  	 ir_dereference *rhs_var_ref =
  	    new(ctx) ir_dereference_variable(rhs_var);
  	 ir_instruction *inst = new(ctx) ir_assignment(rhs_var_ref, rhs, NULL);
  	 instructions->push_tail(inst);
  
  	 /* Assign the current parameter to as many components of the matrix
  	  * as it will fill.
  	  *
  	  * NOTE: A single vector parameter can span two matrix columns.  A
  	  * single vec4, for example, can completely fill a mat2.
  	  */
  	 if (rhs_components >= components_remaining_this_column) {
  	    const unsigned count = MIN2(rhs_components,
  					components_remaining_this_column);
  
  	    rhs_var_ref = new(ctx) ir_dereference_variable(rhs_var);
  
  	    ir_instruction *inst = assign_to_matrix_column(var, col_idx,
  							   row_idx,
  							   rhs_var_ref, 0,
  							   count, ctx);
  	    instructions->push_tail(inst);
  
  	    rhs_base = count;
  
  	    col_idx++;
  	    row_idx = 0;
  	 }
  
  	 /* If there is data left in the parameter and components left to be
  	  * set in the destination, emit another assignment.  It is possible
  	  * that the assignment could be of a vec4 to the last element of the
  	  * matrix.  In this case col_idx==cols, but there is still data
  	  * left in the source parameter.  Obviously, don't emit an assignment
  	  * to data outside the destination matrix.
  	  */
  	 if ((col_idx < cols) && (rhs_base < rhs_components)) {
  	    const unsigned count = rhs_components - rhs_base;
  
  	    rhs_var_ref = new(ctx) ir_dereference_variable(rhs_var);
  
  	    ir_instruction *inst = assign_to_matrix_column(var, col_idx,
  							   row_idx,
  							   rhs_var_ref,
  							   rhs_base,
  							   count, ctx);
  	    instructions->push_tail(inst);
  
  	    row_idx += count;
  	 }
        }
     }
  
     return new(ctx) ir_dereference_variable(var);
  }
  
  
  ir_rvalue *
  emit_inline_record_constructor(const glsl_type *type,
  			       exec_list *instructions,
  			       exec_list *parameters,
  			       void *mem_ctx)
  {
     ir_variable *const var =
        new(mem_ctx) ir_variable(type, "record_ctor", ir_var_temporary, glsl_precision_undefined);
     ir_dereference_variable *const d = new(mem_ctx) ir_dereference_variable(var);
  
     instructions->push_tail(var);
  
     exec_node *node = parameters->head;
     for (unsigned i = 0; i < type->length; i++) {
        assert(!node->is_tail_sentinel());
  
        ir_dereference *const lhs =
  	 new(mem_ctx) ir_dereference_record(d->clone(mem_ctx, NULL),
  					    type->fields.structure[i].name);
  
        ir_rvalue *const rhs = ((ir_instruction *) node)->as_rvalue();
        assert(rhs != NULL);
  
        ir_instruction *const assign = new(mem_ctx) ir_assignment(lhs, rhs, NULL);
  
        instructions->push_tail(assign);
        node = node->next;
     }
  
     return d;
  }
  
  
  ir_rvalue *
  ast_function_expression::hir(exec_list *instructions,
  			     struct _mesa_glsl_parse_state *state)
  {
     void *ctx = state;
     /* There are three sorts of function calls.
      *
      * 1. constructors - The first subexpression is an ast_type_specifier.
      * 2. methods - Only the .length() method of array types.
      * 3. functions - Calls to regular old functions.
      *
      * Method calls are actually detected when the ast_field_selection
      * expression is handled.
      */
     if (is_constructor()) {
        const ast_type_specifier *type = (ast_type_specifier *) subexpressions[0];
        YYLTYPE loc = type->get_location();
        const char *name;
  
        const glsl_type *const constructor_type = type->glsl_type(& name, state);
  
        /* constructor_type can be NULL if a variable with the same name as the
         * structure has come into scope.
         */
        if (constructor_type == NULL) {
  	 _mesa_glsl_error(& loc, state, "unknown type `%s' (structure name "
  			  "may be shadowed by a variable with the same name)",
  			  type->type_name);
  	 return ir_rvalue::error_value(ctx);
        }
  
  
        /* Constructors for samplers are illegal.
         */
        if (constructor_type->is_sampler()) {
  	 _mesa_glsl_error(& loc, state, "cannot construct sampler type `%s'",
  			  constructor_type->name);
  	 return ir_rvalue::error_value(ctx);
        }
  
        if (constructor_type->is_array()) {
  	 if (state->language_version <= 110) {
  	    _mesa_glsl_error(& loc, state,
  			     "array constructors forbidden in GLSL 1.10");
  	    return ir_rvalue::error_value(ctx);
  	 }
  
  	 return process_array_constructor(instructions, constructor_type,
  					  & loc, &this->expressions, state);
        }
  
  
        /* There are two kinds of constructor call.  Constructors for built-in
         * language types, such as mat4 and vec2, are free form.  The only
         * requirement is that the parameters must provide enough values of the
         * correct scalar type.  Constructors for arrays and structures must
         * have the exact number of parameters with matching types in the
         * correct order.  These constructors follow essentially the same type
         * matching rules as functions.
         */
        if (constructor_type->is_record()) {
  	 exec_list actual_parameters;
  
  	 process_parameters(instructions, &actual_parameters,
  			    &this->expressions, state);
  
  	 exec_node *node = actual_parameters.head;
  	 for (unsigned i = 0; i < constructor_type->length; i++) {
  	    ir_rvalue *ir = (ir_rvalue *) node;
  
  	    if (node->is_tail_sentinel()) {
  	       _mesa_glsl_error(&loc, state,
  				"insufficient parameters to constructor "
  				"for `%s'",
  				constructor_type->name);
  	       return ir_rvalue::error_value(ctx);
  	    }
  
  	    if (apply_implicit_conversion(constructor_type->fields.structure[i].type,
  					  ir, state)) {
  	       node->replace_with(ir);
  	    } else {
  	       _mesa_glsl_error(&loc, state,
  				"parameter type mismatch in constructor "
  				"for `%s.%s' (%s vs %s)",
  				constructor_type->name,
  				constructor_type->fields.structure[i].name,
  				ir->type->name,
  				constructor_type->fields.structure[i].type->name);
  	       return ir_rvalue::error_value(ctx);;
  	    }
  
  	    node = node->next;
  	 }
  
  	 if (!node->is_tail_sentinel()) {
  	    _mesa_glsl_error(&loc, state, "too many parameters in constructor "
  			     "for `%s'", constructor_type->name);
  	    return ir_rvalue::error_value(ctx);
  	 }
  
  	 ir_rvalue *const constant =
  	    constant_record_constructor(constructor_type, &actual_parameters,
  					state);
  
  	 return (constant != NULL)
  	    ? constant
  	    : emit_inline_record_constructor(constructor_type, instructions,
  					     &actual_parameters, state);
        }
  
        if (!constructor_type->is_numeric() && !constructor_type->is_boolean())
  	 return ir_rvalue::error_value(ctx);
  
        /* Total number of components of the type being constructed. */
        const unsigned type_components = constructor_type->components();
  
        /* Number of components from parameters that have actually been
         * consumed.  This is used to perform several kinds of error checking.
         */
        unsigned components_used = 0;
  
        unsigned matrix_parameters = 0;
        unsigned nonmatrix_parameters = 0;
        exec_list actual_parameters;
  
        foreach_list (n, &this->expressions) {
  	 ast_node *ast = exec_node_data(ast_node, n, link);
  	 ir_rvalue *result = ast->hir(instructions, state)->as_rvalue();
  
  	 /* From page 50 (page 56 of the PDF) of the GLSL 1.50 spec:
  	  *
  	  *    "It is an error to provide extra arguments beyond this
  	  *    last used argument."
  	  */
  	 if (components_used >= type_components) {
  	    _mesa_glsl_error(& loc, state, "too many parameters to `%s' "
  			     "constructor",
  			     constructor_type->name);
  	    return ir_rvalue::error_value(ctx);
  	 }
  
  	 if (!result->type->is_numeric() && !result->type->is_boolean()) {
  	    _mesa_glsl_error(& loc, state, "cannot construct `%s' from a "
  			     "non-numeric data type",
  			     constructor_type->name);
  	    return ir_rvalue::error_value(ctx);
  	 }
  
  	 /* Count the number of matrix and nonmatrix parameters.  This
  	  * is used below to enforce some of the constructor rules.
  	  */
  	 if (result->type->is_matrix())
  	    matrix_parameters++;
  	 else
  	    nonmatrix_parameters++;
  
  	 actual_parameters.push_tail(result);
  	 components_used += result->type->components();
        }
  
        /* From page 28 (page 34 of the PDF) of the GLSL 1.10 spec:
         *
         *    "It is an error to construct matrices from other matrices. This
         *    is reserved for future use."
         */
        if (state->language_version == 110 && matrix_parameters > 0
  	  && constructor_type->is_matrix()) {
  	 _mesa_glsl_error(& loc, state, "cannot construct `%s' from a "
  			  "matrix in GLSL 1.10",
  			  constructor_type->name);
  	 return ir_rvalue::error_value(ctx);
        }
  
        /* From page 50 (page 56 of the PDF) of the GLSL 1.50 spec:
         *
         *    "If a matrix argument is given to a matrix constructor, it is
         *    an error to have any other arguments."
         */
        if ((matrix_parameters > 0)
  	  && ((matrix_parameters + nonmatrix_parameters) > 1)
  	  && constructor_type->is_matrix()) {
  	 _mesa_glsl_error(& loc, state, "for matrix `%s' constructor, "
  			  "matrix must be only parameter",
  			  constructor_type->name);
  	 return ir_rvalue::error_value(ctx);
        }
  
        /* From page 28 (page 34 of the PDF) of the GLSL 1.10 spec:
         *
         *    "In these cases, there must be enough components provided in the
         *    arguments to provide an initializer for every component in the
         *    constructed value."
         */
        if (components_used < type_components && components_used != 1
  	  && matrix_parameters == 0) {
  	 _mesa_glsl_error(& loc, state, "too few components to construct "
  			  "`%s'",
  			  constructor_type->name);
  	 return ir_rvalue::error_value(ctx);
        }
  
        /* Later, we cast each parameter to the same base type as the
         * constructor.  Since there are no non-floating point matrices, we
         * need to break them up into a series of column vectors.
         */
        if (constructor_type->base_type != GLSL_TYPE_FLOAT) {
  	 foreach_list_safe(n, &actual_parameters) {
  	    ir_rvalue *matrix = (ir_rvalue *) n;
  
  	    if (!matrix->type->is_matrix())
  	       continue;
  
  	    /* Create a temporary containing the matrix. */
  	    ir_variable *var = new(ctx) ir_variable(matrix->type, "matrix_tmp",
  						    ir_var_temporary, matrix->get_precision());
  	    instructions->push_tail(var);
  	    instructions->push_tail(new(ctx) ir_assignment(new(ctx)
  	       ir_dereference_variable(var), matrix, NULL));
  	    var->constant_value = matrix->constant_expression_value();
  
  	    /* Replace the matrix with dereferences of its columns. */
  	    for (int i = 0; i < (int)matrix->type->matrix_columns; i++) {
  	       matrix->insert_before(new (ctx) ir_dereference_array(var,
  		  new(ctx) ir_constant(i)));
  	    }
  	    matrix->remove();
  	 }
        }
  
        bool all_parameters_are_constant = true;
  
        /* Type cast each parameter and, if possible, fold constants.*/
        foreach_list_safe(n, &actual_parameters) {
  	 ir_rvalue *ir = (ir_rvalue *) n;
  
  	 const glsl_type *desired_type =
  	    glsl_type::get_instance(constructor_type->base_type,
  				    ir->type->vector_elements,
  				    ir->type->matrix_columns);
  	 ir_rvalue *result = convert_component(ir, desired_type);
  
  	 /* Attempt to convert the parameter to a constant valued expression.
  	  * After doing so, track whether or not all the parameters to the
  	  * constructor are trivially constant valued expressions.
  	  */
  	 ir_rvalue *const constant = result->constant_expression_value();
  
  	 if (constant != NULL)
  	    result = constant;
  	 else
  	    all_parameters_are_constant = false;
  
  	 if (result != ir) {
  	    ir->replace_with(result);
  	 }
        }
  
        /* If all of the parameters are trivially constant, create a
         * constant representing the complete collection of parameters.
         */
        if (all_parameters_are_constant) {
  	 return new(ctx) ir_constant(constructor_type, &actual_parameters);
        } else if (constructor_type->is_scalar()) {
  	 return dereference_component((ir_rvalue *) actual_parameters.head,
  				      0);
        } else if (constructor_type->is_vector()) {
  	 return emit_inline_vector_constructor(constructor_type, type->precision,
  					       instructions,
  					       &actual_parameters,
  					       ctx);
        } else {
  	 assert(constructor_type->is_matrix());
  	 return emit_inline_matrix_constructor(constructor_type, type->precision,
  					       instructions,
  					       &actual_parameters,
  					       ctx);
        }
     } else {
        const ast_expression *id = subexpressions[0];
        const char *func_name = id->primary_expression.identifier;
        YYLTYPE loc = id->get_location();
        exec_list actual_parameters;
  
        process_parameters(instructions, &actual_parameters, &this->expressions,
  			 state);
  
        ir_function_signature *sig =
  	 match_function_by_name(func_name, &actual_parameters, state);
  
        ir_call *call = NULL;
        ir_rvalue *value = NULL;
        if (sig == NULL) {
  	 no_matching_function_error(func_name, &loc, &actual_parameters, state);
  	 value = ir_rvalue::error_value(ctx);
        } else if (!verify_parameter_modes(state, sig, actual_parameters, this->expressions)) {
  	 /* an error has already been emitted */
  	 value = ir_rvalue::error_value(ctx);
        } else {
  	 value = generate_call(instructions, sig, &loc, &actual_parameters,
  			       &call, state);
        }
  
        return value;
     }
  
     return ir_rvalue::error_value(ctx);
  }
  