switches.c

   1
   2 #include "code.h"
   3 #include "utils.h"
   4
   5 static
   6 int check_switch (struct code *c, struct codeswitch *cs)
   7 {
   8   struct location *loc = cs->location;
   9   element el;
  10   uint32 def, used;
  11
  12   if (!loc->insn) return 0;
  13
  14   if (loc->insn->insn == I_LW) {
  15     def = location_gpr_defined (loc);
  16     while (1) {
  17       if (loc++ == c->end) return 0;
  18       if (!loc->insn) return 0;
  19       used = location_gpr_used (loc);
  20       if (used & def) {
  21         if (loc->insn->insn != I_JR)
  22           return 0;
  23         break;
  24       }
  25       if (loc->insn->flags & (INSN_JUMP | INSN_BRANCH)) return 0;
  26     }
  27   } else if (loc->insn->insn == I_ADDIU) {
  28     int count = 0;
  29     def = location_gpr_defined (loc);
  30     while (1) {
  31       if (loc++ == c->end) return 0;
  32       if (!loc->insn) return 0;
  33       used = location_gpr_used (loc);
  34       if (used & def) {
  35         if (count == 0) {
  36           if (loc->insn->insn != I_ADDU) return 0;
  37         } else if (count == 1) {
  38           if (loc->insn->insn != I_LW) return 0;
  39         } else {
  40           if (loc->insn->insn != I_JR)
  41             return 0;
  42           break;
  43         }
  44         count++;
  45         def = location_gpr_defined (loc);
  46       }
  47       if (loc->insn->flags & (INSN_JUMP | INSN_BRANCH)) return 0;
  48     }
  49   } else return 0;
  50
  51   cs->jumplocation = loc;
  52   cs->jumplocation->cswitch = cs;
  53
  54   el = list_head (cs->references);
  55   while (el) {
  56     struct location *target = element_getvalue (el);
  57     target->cswitch = cs;
  58     el = element_next (el);
  59   }
  60
  61   return 1;
  62 }
  63
  64 void extract_switches (struct code *c)
  65 {
  66   struct prx_reloc *aux;
  67   uint32 base, end, count = 0;
  68   uint32 i, j, tgt;
  69
  70   for (i = 0; i < c->file->relocnum; i++) {
  71     struct prx_reloc *rel = &c->file->relocsbyaddr[i];
  72     count = 0;
  73     do {
  74       if (rel->type != R_MIPS_32) break;
  75       tgt = (rel[count].target - c->baddr) >> 2;
  76       if (tgt >= c->numopc) break;
  77       if (rel[count].target & 0x03) break;
  78
  79       count++;
  80     } while ((i + count) < c->file->relocnum);
  81
  82     if (count == 0) continue;
  83
  84     base = end = prx_findreloc (c->file, rel->vaddr);
  85     if (base >= c->file->relocnum) continue;
  86     if (c->file->relocs[base].target != rel->vaddr) continue;
  87
  88     for (; end < c->file->relocnum; end++) {
  89       aux = &c->file->relocs[end];
  90       if (aux->target != rel->vaddr) {
  91         if (aux->target & 0x03) {
  92           error (__FILE__ ": relocation target not word aligned 0x%08X", aux->target);
  93           count = 0;
  94         } else if (count > ((aux->target - rel->vaddr) >> 2))
  95           count = (aux->target - rel->vaddr) >> 2;
  96         break;
  97       }
  98     }
  99
 100     if (count <= 1) continue;
 101
 102     for (;base < end; base++) {
 103       aux = &c->file->relocs[base];
 104       tgt = (aux->vaddr - c->baddr) >> 2;
 105       if (tgt >= c->numopc) continue;
 106       if (aux->vaddr & 0x03) {
 107         error (__FILE__ ": relocation vaddr not word aligned 0x%08X", aux->vaddr);
 108         continue;
 109       }
 110
 111       if (aux->type == R_MIPS_LO16) {
 112         struct codeswitch *cs;
 113
 114         cs = fixedpool_alloc (c->switchpool);
 115
 116         cs->jumpreloc = aux;
 117         cs->switchreloc = rel;
 118         cs->location = &c->base[tgt];
 119         cs->count = count;
 120         cs->references = list_alloc (c->lstpool);
 121         for (j = 0; j < count; j++) {
 122           tgt = (rel[j].target - c->baddr) >> 2;
 123           list_inserttail (cs->references, &c->base[tgt]);
 124         }
 125
 126         if (!check_switch (c, cs)) {
 127           fixedpool_free (c->switchpool, cs);
 128         }
 129       }
 130     }
 131   }
 132 }
 133
 134