1 /* Copyright (C) 1998 - 2000 by Universitaet Karlsruhe
2 ** All rights reserved.
4 ** Authors: Christian Schaefer, Goetz Lindenmaier
15 * a dead block / unreachable code.
19 *** This file constructs a control flow of following shape:
26 *** Block1 Block2 deadBlock
33 *** This is a program as, e.g.,
36 *** { Jmp label1; } // happens anyways
38 *** { Jmp label1; } // happens anyways
45 int main(int argc, char **argv)
47 ir_graph *irg; /* this variable contains the irgraph */
48 type_class *owner; /* the class in which this method is defined */
49 type_method *proc_main; /* type information for the method main */
50 entity *ent; /* represents this method as entity of owner */
51 ir_node *c1, *c2, *cond, *f, *t, *endBlock, *Block1, *jmp, *Block2,
57 /* FIRM was designed for oo languages where all methods belong to a class.
58 * For imperative languages like C we view a file as a large class containing
59 * all functions as methods in this file.
60 * Therefore we define a class "empty" according to the file name
61 * with a method main as an entity.
63 #define CLASSNAME "DEAD_BLOCK"
64 #define METHODNAME "main"
67 printf("creating an IR graph: %s...\n", CLASSNAME);
69 owner = new_type_class (id_from_str (CLASSNAME, strlen(CLASSNAME)));
70 proc_main = new_type_method(id_from_str(METHODNAME, strlen(METHODNAME)),
72 ent = new_entity ((type *)owner,
73 id_from_str (METHODNAME, strlen(METHODNAME)),
76 #define NUM_OF_LOCAL_VARS 1
78 irg = new_ir_graph (ent, NUM_OF_LOCAL_VARS);
80 /* two make a condition */
81 c1 = new_Const (mode_i, tarval_from_long (mode_i, 1));
82 c2 = new_Const (mode_i, tarval_from_long (mode_i, 2));
84 cond = new_Cond(new_Proj(new_Cmp(c1, c2), mode_b, Eq));
85 f = new_Proj(cond, mode_X, 0);
86 t = new_Proj(cond, mode_X, 1);
87 mature_block(irg->current_block);
89 /* end block to add jmps */
90 endBlock = new_Block();
94 add_in_edge(Block1, t);
97 add_in_edge(endBlock, jmp);
100 Block2 = new_Block();
101 add_in_edge(Block2, f);
102 mature_block(Block2);
105 add_in_edge(endBlock, jmp);
108 deadBlock = new_Block();
109 mature_block(deadBlock);
111 add_in_edge(endBlock, jmp);
113 switch_block(endBlock);
116 in[0] = get_value(0, mode_i);
117 x = new_Return (get_store(), 1, in);
119 mature_block (irg->current_block);
121 add_in_edge (irg->end_block, x);
122 mature_block (irg->end_block);
124 /* verify the graph */
127 printf("\nDone building the graph.\n");
128 local_optimize_graph (irg);
129 printf("\nDone local optimization.\n");
130 set_opt_constant_folding (1);
133 dead_node_elimination (irg);
134 printf("Dumping the graph and a control flow graph.\n");
136 dump_ir_block_graph (irg);
139 printf("use xvcg to view these graphs:\n");
140 printf("/ben/goetz/bin/xvcg GRAPHNAME\n");