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", 7), 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);
83 get_entity_ld_name(proc_main_e); /* force name mangling */
85 /* make type information for the array and set the bounds */
89 array_type = new_type_array(id_from_str("a_tp", 4), N_DIMS, prim_t_int);
90 current_ir_graph = get_const_code_irg();
91 set_array_bounds(array_type, 0,
92 new_Const(mode_Iu, new_tarval_from_long (L_BOUND, mode_Iu)),
93 new_Const(mode_Iu, new_tarval_from_long (U_BOUND, mode_Iu)));
95 main_irg = new_ir_graph (proc_main_e, 4);
97 /* The array is an entity of the method, placed on the mehtod's own memory,
99 array_ent = new_entity(get_cur_frame_type(), id_from_str("a", 1), array_type);
100 /* As the array is accessed by Sel nodes, we need information about
101 the entity the node selects. Entities of an array are it's elements
102 which are, in this case, integers. */
103 /* change entity owner types. */
104 field_ent = get_array_element_entity(array_type);
108 /* Now the "real" program: */
109 /* Select the array from the stack frame. */
110 array_ptr = new_simpleSel(get_store(), get_irg_frame(main_irg), array_ent);
111 /* Load element 3 of the array. For this first generate the pointer
112 to this the element by a select node. (Alternative: increase
113 array pointer by (three * elt_size), but this complicates some
114 optimizations.) The type information accessible via the entity
115 allows to generate the pointer increment later. */
116 c3 = new_Const (mode_Iu, new_tarval_from_long (3, mode_Iu));
120 elt = new_Sel(get_store(), array_ptr, 1, in, field_ent);
122 val = new_Load(get_store(), elt);
123 set_store(new_Proj(val, mode_M, 0));
124 val = new_Proj(val, mode_Is, 2);
126 /* return the result of procedure main */
131 x = new_Return (get_store (), 1, in);
133 mature_block (get_irg_current_block(main_irg));
135 /* complete the end_block */
136 add_in_edge (get_irg_end_block(main_irg), x);
137 mature_block (get_irg_end_block(main_irg));
139 finalize_cons (main_irg);
141 printf("Optimizing ...\n");
142 dead_node_elimination(main_irg);
144 /* verify the graph */
147 printf("Dumping the graph and a type graph.\n");
148 dump_ir_block_graph (main_irg);
149 dump_type_graph(main_irg);
150 dump_ir_block_graph_w_types(main_irg);
152 printf("Use xvcg to view these graphs:\n");
153 printf("/ben/goetz/bin/xvcg GRAPHNAME\n\n");