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[qfcc] Analyze assignment through const pointers 

This fixes a false-positive uninitialized warning.
This commit is contained in:
Bill Currie 2020-03-17 01:40:35 +09:00
parent 8e6baf1bde
commit fd06cd2b00
1 changed files with 36 additions and 20 deletions
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56
tools/qfcc/source/flow.c
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@ -1040,7 +1040,7 @@ flow_add_op_var (set_t *set, operand_t *op, int is_use)
set_add (set, var->number);
// FIXME XXX I think the curent implementation will have problems
// for the def set when assinging to an alias as right now the real
// for the def set when assigning to an alias as right now the real
// var is being treated as assigned as well. Want to handle partial
// defs properly, but I am as yet uncertain of how.
if (op->op_type == op_temp) {
@ -1050,6 +1050,28 @@ flow_add_op_var (set_t *set, operand_t *op, int is_use)
}
}
static int
flow_analyize_pointer_operand (operand_t *ptrop, set_t *def,
operand_t *operands[4])
{
if (ptrop->op_type == op_value
&& ptrop->o.value->lltype == ev_pointer
&& ptrop->o.value->v.pointer.def) {
operand_t *op;
def_t *alias;
ex_pointer_t *ptr = &ptrop->o.value->v.pointer;
alias = alias_def (ptr->def, ptr->type, ptr->val);
op = def_operand (alias, ptr->type, ptrop->expr);
flow_add_op_var (def, op, 0);
if (operands)
operands[0] = op;
else
free_operand (op);
return 1;
}
return 0;
}
void
flow_analyze_statement (statement_t *s, set_t *use, set_t *def, set_t *kill,
operand_t *operands[4])
@ -1099,37 +1121,31 @@ flow_analyze_statement (statement_t *s, set_t *use, set_t *def, set_t *kill,
} else if (!strcmp (s->opcode, "<MOVEP>")
|| !strcmp (s->opcode, "<MEMSETP>")) {
flow_add_op_var (use, s->opc, 0);
if (s->opc->op_type == op_value
&& s->opc->o.value->lltype == ev_pointer
&& s->opc->o.value->v.pointer.def) {
operand_t *op;
def_t *alias;
ex_pointer_t *ptr = &s->opc->o.value->v.pointer;
alias = alias_def (ptr->def, ptr->type, ptr->val);
op = def_operand (alias, ptr->type, s->opc->expr);
flow_add_op_var (def, op, 0);
if (operands)
operands[0] = op;
else
free_operand (op);
} else {
if (operands)
if (!flow_analyize_pointer_operand (s->opc, def, operands)) {
if (operands) {
operands[3] = s->opc;
}
}
} else if (!strcmp (s->opcode, ".=")) {
flow_add_op_var (use, s->opc, 1);
flow_analyize_pointer_operand (s->opb, def, operands);
} else {
if (s->opc)
flow_add_op_var (use, s->opc, 1);
internal_error (s->expr, "unexpected opcode '%s' for %d",
s->opcode, s->type);
}
if (kill) {
set_everything (kill);
}
if (operands) {
if (!strcmp (s->opcode, "<MOVE>"))
if (!strcmp (s->opcode, "<MOVE>")
|| !strcmp (s->opcode, "<MEMSET>")) {
operands[0] = s->opc;
}
operands[1] = s->opa;
operands[2] = s->opb;
if (strncmp (s->opcode, "<MOVE", 5))
if (strncmp (s->opcode, "<MOVE", 5)) {
operands[3] = s->opc;
}
}
break;
case st_state: