3 * File name: testprograms/array-stack_example.c
4 * Purpose: Show representation of array on stack.
5 * Author: Goetz Lindenmaier
9 * Copyright: (c) 1999-2003 Universität Karlsruhe
10 * Licence: This file protected by GPL - GNU GENERAL PUBLIC LICENSE.
22 * imperative programs.
23 * It constructs the IR for the following program:
32 * The array is placed on the stack, i.e., a pointer to the array
33 * is obtained by selecting the entity "a" from the stack. The variables
34 * on the stack are considered to be entities of the method, as locals
35 * of a method are only visible within the method. (An alternative to
36 * make the method owner of the stack variables is to give the ownership
37 * to the class representing the C-file. This would extend the visibility
38 * of the locals, though.)
42 #define OPTIMIZE_NODE 0
47 /* describes the general structure of a C-file */
48 type *owner; /* the class standing for everything in this file */
49 type *proc_main; /* Typeinformation for method main. */
50 entity *proc_main_e; /* The entity describing that method main is an
51 entity of the fake class representing the file. */
53 /* describes types defined by the language */
56 /* describes the array and its fields. */
57 entity *array_ent; /* the entity representing the array as member
58 of the stack/method */
59 type *array_type; /* the type information for the array */
60 entity *field_ent; /* the entity representing a field of the
63 /* holds the graph and nodes. */
65 ir_node *array_ptr, *c3, *elt, *val, *x;
69 printf("\nCreating an IR graph: ARRAY-STACK_EXAMPLE...\n");
71 /* make basic type information for primitive type int.
72 In Sather primitive types are represented by a class.
73 This is the modeling appropriate for other languages.
74 Mode_i says that all language-integers shall be implemented
75 as a 32 bit processor-integer value. */
76 prim_t_int = new_type_primitive(id_from_str ("int", 3), mode_Is);
78 /* build typeinformation of procedure main */
79 owner = new_type_class (id_from_str ("ARRAY-STACK_EXAMPLE", 19));
80 proc_main = new_type_method(id_from_str("main_tp", 4), 0, 1);
81 set_method_res_type(proc_main, 0, prim_t_int);
82 proc_main_e = new_entity (owner, id_from_str ("main", 4), proc_main);
84 /* make type information for the array and set the bounds */
88 array_type = new_type_array(id_from_str("a_tp", 4), N_DIMS, prim_t_int);
89 current_ir_graph = get_const_code_irg();
90 set_array_bounds(array_type, 0,
91 new_Const(mode_Iu, new_tarval_from_long (L_BOUND, mode_Iu)),
92 new_Const(mode_Iu, new_tarval_from_long (U_BOUND, mode_Iu)));
94 main_irg = new_ir_graph (proc_main_e, 4);
96 /* The array is an entity of the method, placed on the mehtod's own memory,
98 array_ent = new_entity(get_cur_frame_type(), id_from_str("a", 1), array_type);
99 /* As the array is accessed by Sel nodes, we need information about
100 the entity the node selects. Entities of an array are it's elements
101 which are, in this case, integers. */
102 /* change entity owner types. */
103 field_ent = get_array_element_entity(array_type);
107 /* Now the "real" program: */
108 /* Select the array from the stack frame. */
109 array_ptr = new_simpleSel(get_store(), get_irg_frame(main_irg), array_ent);
110 /* Load element 3 of the array. For this first generate the pointer
111 to this the element by a select node. (Alternative: increase
112 array pointer by (three * elt_size), but this complicates some
113 optimizations.) The type information accessible via the entity
114 allows to generate the pointer increment later. */
115 c3 = new_Const (mode_Iu, new_tarval_from_long (3, mode_Iu));
119 elt = new_Sel(get_store(), array_ptr, 1, in, field_ent);
121 val = new_Load(get_store(), elt);
122 set_store(new_Proj(val, mode_M, 0));
123 val = new_Proj(val, mode_Is, 2);
125 /* return the result of procedure main */
130 x = new_Return (get_store (), 1, in);
132 mature_block (get_irg_current_block(main_irg));
134 /* complete the end_block */
135 add_in_edge (get_irg_end_block(main_irg), x);
136 mature_block (get_irg_end_block(main_irg));
138 finalize_cons (main_irg);
140 printf("Optimizing ...\n");
141 dead_node_elimination(main_irg);
143 /* verify the graph */
146 printf("Dumping the graph and a type graph.\n");
147 dump_ir_block_graph (main_irg);
148 dump_type_graph(main_irg);
149 dump_ir_block_graph_w_types(main_irg);
151 printf("Use xvcg to view these graphs:\n");
152 printf("/ben/goetz/bin/xvcg GRAPHNAME\n\n");