codegen/valadovaassignmentmodule.vala

   1 /* valadovaassignmentmodule.vala
   2  *
   3  * Copyright (C) 2006-2010  Jürg Billeter
   4  *
   5  * This library is free software; you can redistribute it and/or
   6  * modify it under the terms of the GNU Lesser General Public
   7  * License as published by the Free Software Foundation; either
   8  * version 2.1 of the License, or (at your option) any later version.
   9
  10  * This library is distributed in the hope that it will be useful,
  11  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  13  * Lesser General Public License for more details.
  14
  15  * You should have received a copy of the GNU Lesser General Public
  16  * License along with this library; if not, write to the Free Software
  17  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301  USA
  18  *
  19  * Author:
  20  *      Jürg Billeter <j@bitron.ch>
  21  */
  22
  23 /**
  24  * The link between an assignment and generated code.
  25  */
  26 public class Vala.DovaAssignmentModule : DovaMemberAccessModule {
  27         CCodeExpression? emit_simple_assignment (Assignment assignment) {
  28                 CCodeExpression rhs = get_cvalue (assignment.right);
  29                 CCodeExpression lhs = (CCodeExpression) get_ccodenode (assignment.left);
  30
  31                 bool unref_old = requires_destroy (assignment.left.value_type);
  32
  33                 if (unref_old) {
  34                         if (!is_pure_ccode_expression (lhs)) {
  35                                 /* Assign lhs to temp var to avoid repeating side effect */
  36                                 var lhs_value_type = assignment.left.value_type.copy ();
  37                                 string lhs_temp_name = "_tmp%d_".printf (next_temp_var_id++);
  38                                 var lhs_temp = new LocalVariable (lhs_value_type, "*" + lhs_temp_name);
  39                                 emit_temp_var (lhs_temp);
  40                                 ccode.add_assignment (get_variable_cexpression (lhs_temp_name), new CCodeUnaryExpression (CCodeUnaryOperator.ADDRESS_OF, lhs));
  41                                 lhs = new CCodeParenthesizedExpression (new CCodeUnaryExpression (CCodeUnaryOperator.POINTER_INDIRECTION, get_variable_cexpression (lhs_temp_name)));
  42                         }
  43
  44                         var temp_decl = get_temp_variable (assignment.left.value_type);
  45                         emit_temp_var (temp_decl);
  46                         ccode.add_assignment (get_variable_cexpression (temp_decl.name), rhs);
  47                         if (unref_old) {
  48                                 /* unref old value */
  49                                 ccode.add_expression (get_unref_expression (lhs, assignment.left.value_type, assignment.left));
  50                         }
  51
  52                         rhs = get_variable_cexpression (temp_decl.name);
  53                 }
  54
  55                 var cop = CCodeAssignmentOperator.SIMPLE;
  56                 if (assignment.operator == AssignmentOperator.BITWISE_OR) {
  57                         cop = CCodeAssignmentOperator.BITWISE_OR;
  58                 } else if (assignment.operator == AssignmentOperator.BITWISE_AND) {
  59                         cop = CCodeAssignmentOperator.BITWISE_AND;
  60                 } else if (assignment.operator == AssignmentOperator.BITWISE_XOR) {
  61                         cop = CCodeAssignmentOperator.BITWISE_XOR;
  62                 } else if (assignment.operator == AssignmentOperator.ADD) {
  63                         cop = CCodeAssignmentOperator.ADD;
  64                 } else if (assignment.operator == AssignmentOperator.SUB) {
  65                         cop = CCodeAssignmentOperator.SUB;
  66                 } else if (assignment.operator == AssignmentOperator.MUL) {
  67                         cop = CCodeAssignmentOperator.MUL;
  68                 } else if (assignment.operator == AssignmentOperator.DIV) {
  69                         cop = CCodeAssignmentOperator.DIV;
  70                 } else if (assignment.operator == AssignmentOperator.PERCENT) {
  71                         cop = CCodeAssignmentOperator.PERCENT;
  72                 } else if (assignment.operator == AssignmentOperator.SHIFT_LEFT) {
  73                         cop = CCodeAssignmentOperator.SHIFT_LEFT;
  74                 } else if (assignment.operator == AssignmentOperator.SHIFT_RIGHT) {
  75                         cop = CCodeAssignmentOperator.SHIFT_RIGHT;
  76                 }
  77
  78                 CCodeExpression codenode = new CCodeAssignment (lhs, rhs, cop);
  79
  80                 ccode.add_expression (codenode);
  81
  82                 if (assignment.parent_node is ExpressionStatement) {
  83                         return null;
  84                 } else {
  85                         return lhs;
  86                 }
  87         }
  88
  89         CCodeExpression? emit_fixed_length_array_assignment (Assignment assignment, ArrayType array_type) {
  90                 CCodeExpression rhs = get_cvalue (assignment.right);
  91                 CCodeExpression lhs = (CCodeExpression) get_ccodenode (assignment.left);
  92
  93                 // it is necessary to use memcpy for fixed-length (stack-allocated) arrays
  94                 // simple assignments do not work in C
  95                 var sizeof_call = new CCodeFunctionCall (new CCodeIdentifier ("sizeof"));
  96                 sizeof_call.add_argument (new CCodeIdentifier (array_type.element_type.get_cname ()));
  97                 var size = new CCodeBinaryExpression (CCodeBinaryOperator.MUL, new CCodeConstant ("%d".printf (array_type.length)), sizeof_call);
  98                 var ccopy = new CCodeFunctionCall (new CCodeIdentifier ("memcpy"));
  99                 ccopy.add_argument (lhs);
 100                 ccopy.add_argument (rhs);
 101                 ccopy.add_argument (size);
 102
 103                 ccode.add_expression (ccopy);
 104
 105                 if (assignment.parent_node is ExpressionStatement) {
 106                         return null;
 107                 } else {
 108                         return lhs;
 109                 }
 110         }
 111
 112         public override void visit_assignment (Assignment assignment) {
 113                 if (assignment.left.error || assignment.right.error) {
 114                         assignment.error = true;
 115                         return;
 116                 }
 117
 118                 if (assignment.left.symbol_reference is Property) {
 119                         var ma = assignment.left as MemberAccess;
 120                         var prop = (Property) assignment.left.symbol_reference;
 121
 122                         store_property (prop, ma.inner, assignment.right.target_value);
 123
 124                         set_cvalue (assignment, get_ccodenode (assignment.right));
 125                 } else {
 126                         var array_type = assignment.left.value_type as ArrayType;
 127                         if (array_type != null && array_type.fixed_length) {
 128                                 set_cvalue (assignment, emit_fixed_length_array_assignment (assignment, array_type));
 129                         } else {
 130                                 set_cvalue (assignment, emit_simple_assignment (assignment));
 131                         }
 132                 }
 133         }
 134
 135         void store_variable (Variable variable, TargetValue lvalue, TargetValue value, bool initializer) {
 136                 if (!initializer && requires_destroy (variable.variable_type)) {
 137                         /* unref old value */
 138                         ccode.add_expression (destroy_value (lvalue));
 139                 }
 140
 141                 ccode.add_assignment (get_cvalue_ (lvalue), get_cvalue_ (value));
 142         }
 143
 144         public override void store_local (LocalVariable local, TargetValue value, bool initializer) {
 145                 store_variable (local, get_local_cvalue (local), value, initializer);
 146         }
 147
 148         public override void store_parameter (Parameter param, TargetValue value) {
 149                 store_variable (param, get_parameter_cvalue (param), value, false);
 150         }
 151
 152         public override void store_field (Field field, Expression? instance, TargetValue value) {
 153                 store_variable (field, get_field_cvalue (field, instance), value, false);
 154         }
 155 }