dataflow.c

   1
   2 #include "code.h"
   3 #include "utils.h"
   4
   5 static
   6 void mark_variable (struct variable *var, enum variabletype type, int num)
   7 {
   8   element useel, phiel;
   9   struct value *val;
  10
  11   var->info = num;
  12   var->type = type;
  13   useel = list_head (var->uses);
  14   while (useel) {
  15     struct operation *use = element_getvalue (useel);
  16     if (use->type == OP_PHI) {
  17       phiel = list_head (use->operands);
  18       while (phiel) {
  19         struct value *val = element_getvalue (phiel);
  20         if (val->val.variable->type == VARIABLE_UNK) {
  21           mark_variable (val->val.variable, type, num);
  22         }
  23         phiel = element_next (phiel);
  24       }
  25       val = list_headvalue (use->results);
  26       if (val->val.variable->type == VARIABLE_UNK)
  27         mark_variable (val->val.variable, type, num);
  28     }
  29     useel = element_next (useel);
  30   }
  31
  32   if (var->def->type == OP_PHI) {
  33     phiel = list_head (var->def->operands);
  34     while (phiel) {
  35       struct value *val = element_getvalue (phiel);
  36       if (val->val.variable->type == VARIABLE_UNK) {
  37         mark_variable (val->val.variable, type, num);
  38       }
  39       phiel = element_next (phiel);
  40     }
  41   }
  42 }
  43
  44 void extract_variables (struct subroutine *sub)
  45 {
  46   element varel;
  47   int count = 0;
  48
  49   varel = list_head (sub->variables);
  50   while (varel) {
  51     struct variable *var = element_getvalue (varel);
  52     if (var->type == VARIABLE_UNK) {
  53       if (var->def->type == OP_START) {
  54         mark_variable (var, VARIABLE_ARGUMENT, var->name.val.intval);
  55       } else if (var->def->type == OP_CALL && var->name.val.intval != 2 &&
  56                  var->name.val.intval != 3) {
  57         var->type = VARIABLE_INVALID;
  58       } else {
  59         int istemp = FALSE;
  60
  61         if (list_size (var->uses) <= 1) {
  62           struct operation *op = list_headvalue (var->uses);
  63           if (op) {
  64             if (op->type != OP_PHI)
  65               istemp = TRUE;
  66           } else {
  67             istemp = TRUE;
  68           }
  69         }
  70
  71         if (var->def->type == OP_MOVE || var->def->type == OP_INSTRUCTION) {
  72           if (var->def->type == OP_INSTRUCTION) {
  73             if (var->def->info.iop.loc->insn->flags & (INSN_LOAD | INSN_STORE | INSN_BRANCH))
  74               istemp = FALSE;
  75           }
  76         } else {
  77           istemp = FALSE;
  78         }
  79
  80         if (istemp) {
  81           var->def->deferred = TRUE;
  82           var->type = VARIABLE_TEMP;
  83           var->info = 0;
  84         } else {
  85           mark_variable (var, VARIABLE_LOCAL, ++count);
  86         }
  87       }
  88     }
  89     varel = element_next (varel);
  90   }
  91 }