git.maemo.org Git - opencv/blob - apps/cvenv/EiC/optomizer.c

   1 /* optomizer.c
   2  *
   3  *      (C) Copyright Jul 27 1996, Edmond J. Breen.
   4  *                 ALL RIGHTS RESERVED.
   5  * This code may be copied for personal, non-profit use only.
   6  *
   7  */
   8
   9 #include <stdio.h>
  10 #include <stdlib.h>
  11 #include <string.h>
  12
  13 #include "MachSet.h"
  14 #include "global.h"
  15 #include "typesets.h"
  16 #include "error.h"
  17
  18 #define isgoto(C,i)  (opcode(C,i) >= jmpu && opcode(C,i) <= jmpTptr)
  19
  20 typedef struct {
  21     int ninst;        /* # of instructions */
  22     int leader;       /* block leader */
  23     int nb;           /* number of braches leading from block */
  24     int *branch;      /* branch leaders */
  25 }block_t;
  26
  27 #define crt_block() (block_t*)calloc(sizeof(block_t),1)
  28
  29 #define addbranch(x,y,z)    do{\
  30                                     x = (int*)realloc(x,(y+1)*sizeof(int));\
  31                                     x[y++] = z;\
  32                             }while(0)
  33
  34 static void freeblock(block_t * b, int nb)
  35 {
  36     int i;
  37     for(i =0;i<nb;++i)
  38         if(b[i].branch)
  39             free(b[i].branch);
  40     free(b);
  41 }
  42
  43 static block_t  initblock(code_t *c, int leader, int *visit)
  44 {
  45     int i;
  46     block_t  b;
  47     b.leader = leader;
  48     b.branch = NULL;
  49     b.nb = 0;
  50     b.ninst = 0;
  51
  52     for(i=leader;i<nextinst(c);++i) {
  53         visit[i]++;
  54         b.ninst++;
  55         if(opcode(c,i) == eicreturn)
  56             break;
  57         else if(isgoto(c,i)) {
  58             /*printf("[%d:%d]\n",i,i+ivalcode(c,i));*/
  59             addbranch(b.branch,b.nb,i+ivalcode(c,i));
  60             if(opcode(c,i) != jmpu) {
  61                 /*printf("[%d:%d]\n",i,i+1);*/
  62                 addbranch(b.branch,b.nb,i+1);
  63             }
  64             break;
  65         } else if(opcode(c,i) == jmptab) {
  66             struct {int n;val_t *loc;} *p;
  67             int j;
  68             p = pvalcode(c,i);
  69             addbranch(b.branch,b.nb,i + p->loc[0].ival);
  70             for(j =1;j<p->n;j+=2)
  71                 addbranch(b.branch,b.nb,i + p->loc[j+1].ival);
  72             break;
  73         }
  74     }
  75     if(leader == nextinst(c))
  76         visit[leader]++;
  77     return b;
  78 }
  79
  80
  81 void  EiC_peephole(code_t *C, int *visit)
  82 {
  83     int  i, n,j;
  84     n = nextinst(C);
  85     for(i = 0; i < n; ++i)
  86         if(isgoto(C,i)) {
  87             j = i + ivalcode(C,i);
  88             if(j >= n)
  89                 continue;
  90             if(opcode(C,j) == jmpu || opcode(C,i) == opcode(C,j)) {
  91                 /*visit[i+ivalcode(C,i)]--;*/
  92                 ivalcode(C,i) += ivalcode(C,j);
  93
  94             }
  95         }
  96 }
  97
  98 int EiC_analyseCode(code_t *C)
  99 {
 100     /* returns the index to the last visited instruction */
 101     block_t *block = NULL;
 102
 103     int nb = 0;
 104     int  i,j,rtn;
 105     int *visit;
 106
 107     visit = calloc(sizeof(*visit),nextinst(C)+1);
 108     block = realloc(block,(nb+1)*sizeof(*block));
 109     block[nb++] = initblock(C,0,visit);
 110
 111     for(i=0;i<nb;++i) {
 112         for(j=0;j<block[i].nb;++j) {
 113             if(!visit[block[i].branch[j]]) {
 114                 block = realloc(block,(nb+1)*sizeof(*block));
 115                 block[nb++] = initblock(C,block[i].branch[j],visit);
 116             } else
 117                 visit[block[i].branch[j]]++;
 118         }
 119     }
 120
 121     rtn = 0;
 122     for(i=0;i<=nextinst(C);)
 123         if(visit[i])
 124             rtn = i++;
 125         else if(i < nextinst(C) && instline(C,i)) {
 126             EiC_warningerror("Unreachable code at line %d",instline(C,i));
 127             for(;i<nextinst(C) && !visit[i];i++)
 128                 ;
 129         } else
 130             i++;
 131
 132     EiC_peephole(C,visit);
 133
 134 /*******
 135     for(i=0;i<nextinst(C);++i)
 136         if(!visit[i])
 137         setopcode(C,i,empty);
 138 *******/
 139
 140     freeblock(block,nb);
 141     free(visit);
 142
 143
 144     return rtn;
 145 }
 146
 147
 148 int EiC_checkPeepHole(token_t *e1,int op)
 149 {
 150     /*
 151      * A simple arithmetic optimizer:
 152      * do not add or subtract 0
 153      * and do not multiply  or divide by 1
 154      */
 155     int v = 0;
 156     if (isconst(e1->Type)) {
 157         if (op == '+' || op == '-')
 158             switch (EiC_gettype(e1->Type)) {
 159               CASE_INT: CASE_UINT:v = e1->Val.ival == 0;
 160                 break;
 161               CASE_LONG: CASE_ULONG:v = e1->Val.lval == 0;
 162                 break;
 163               CASE_FLOAT:v = e1->Val.dval == 0;
 164                 break;
 165                 }
 166         else if (op == '*')
 167             switch (EiC_gettype(e1->Type)) {
 168               CASE_INT: CASE_UINT:v = e1->Val.ival == 1;
 169                 break;
 170               CASE_LONG: CASE_ULONG:v = e1->Val.lval == 1;
 171                 break;
 172               CASE_FLOAT:v = e1->Val.dval == 1;
 173                 break;
 174             }
 175         }
 176     return v;
 177 }
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