3 * File name: testprograms/dead_block_example.c
4 * Purpose: Test unreachable code elimination.
5 * Author: Christian Schaefer, Goetz Lindenmaier
9 * Copyright: (c) 1999-2003 Universität Karlsruhe
10 * Licence: This file protected by GPL - GNU GENERAL PUBLIC LICENSE.
21 * a dead block / unreachable code.
25 * This file constructs a control flow of following shape:
32 * Block1 Block2 deadBlock
39 * This is a program as, e.g.,
42 * { Jmp label1; } // happens anyways
44 * { Jmp label1; } // happens anyways
51 int main(int argc, char **argv)
53 ir_graph *irg; /* this variable contains the irgraph */
54 type *owner; /* the class in which this method is defined */
55 type *proc_main; /* type information for the method main */
57 entity *ent; /* represents this method as entity of owner */
58 ir_node *c1, *c2, *cond, *f, *t, *endBlock, *Block1, *jmp, *Block2,
64 /*** Make basic type information for primitive type int. ***/
65 prim_t_int = new_type_primitive(new_id_from_chars ("int", 3), mode_Is);
67 /* FIRM was designed for oo languages where all methods belong to a class.
68 * For imperative languages like C we view a file as a large class containing
69 * all functions as methods in this file.
70 * Therefore we define a class "empty" according to the file name
71 * with a method main as an entity.
73 #define CLASSNAME "DEAD_BLOCK"
74 #define METHODNAME "main"
77 printf("\nCreating an IR graph: %s...\n", CLASSNAME);
79 owner = new_type_class (new_id_from_chars (CLASSNAME, strlen(CLASSNAME)));
80 proc_main = new_type_method(new_id_from_chars(METHODNAME, strlen(METHODNAME)),
82 set_method_res_type(proc_main, 0, prim_t_int);
83 ent = new_entity (owner,
84 new_id_from_chars (METHODNAME, strlen(METHODNAME)),
86 get_entity_ld_name(ent); /* To enforce name mangling for vcg graph name */
87 #define NUM_OF_LOCAL_VARS 1
89 irg = new_ir_graph (ent, NUM_OF_LOCAL_VARS);
91 /* to make a condition */
92 c1 = new_Const (mode_Is, new_tarval_from_long (1, mode_Is));
93 c2 = new_Const (mode_Is, new_tarval_from_long (2, mode_Is));
96 cond = new_Cond(new_Proj(new_Cmp(c1, c2), mode_b, Eq));
97 f = new_Proj(cond, mode_X, 0);
98 t = new_Proj(cond, mode_X, 1);
99 mature_immBlock(get_irg_current_block(irg));
101 /* end block to add jmps */
102 endBlock = new_immBlock();
105 Block1 = new_immBlock();
106 add_immBlock_pred(Block1, t);
107 mature_immBlock(Block1);
109 add_immBlock_pred(endBlock, jmp);
112 Block2 = new_immBlock();
113 add_immBlock_pred(Block2, f);
114 mature_immBlock(Block2);
116 add_immBlock_pred(endBlock, jmp);
119 deadBlock = new_immBlock();
120 mature_immBlock(deadBlock);
122 add_immBlock_pred(endBlock, jmp);
124 /* finish end block */
125 set_cur_block(endBlock);
128 in[0] = get_value(0, mode_Is);
130 x = new_Return (get_store(), 1, in);
132 mature_immBlock (get_irg_current_block(irg));
134 add_immBlock_pred (get_irg_end_block(irg), x);
135 mature_immBlock (get_irg_end_block(irg));
139 printf("Optimizing ...\n");
140 local_optimize_graph (irg);
141 dead_node_elimination (irg);
143 /* verify the graph */
146 printf("Dumping the graph and a control flow graph.\n");
147 char *dump_file_suffix = "";
148 dump_ir_block_graph (irg, dump_file_suffix);
149 dump_cfg (irg, dump_file_suffix);
150 printf("Use xvcg to view these graphs:\n");
151 printf("/ben/goetz/bin/xvcg GRAPHNAME\n\n");