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[qfcc] Reset flowvars for aliased global variables

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When a global variable is accessed via only an alias in a function the
actual def's flowvar would remain in the state it was from the last
function that accessed the global normally. This would result in invalid
flowvar accesses which can be difficult to reproduce (thus no test
case).
This commit is contained in:
Bill Currie 2020-06-25 22:45:12 +09:00
parent 8f2bc18a4f
commit ed42557dd1
1 changed files with 27 additions and 9 deletions
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36
tools/qfcc/source/flow.c
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@ -463,6 +463,15 @@ flow_build_statements (function_t *func)
}
}
static int flow_def_clear_flowvars (def_t *def, void *data)
{
if (def->flowvar) {
delete_flowvar (def->flowvar);
}
def->flowvar = 0;
return 0;
}
/** Build an array of all the variables used by a function
*
* The array exists so variables can be referenced by number and thus used
@ -517,17 +526,26 @@ flow_build_vars (function_t *func)
set_iter_t *var_i;
flowvar_t *var;
// first, count .return and .param_[0-7] as they are always needed
// First, run through the statements making sure any accessed variables
// have their flowvars reset. Local variables will be fine, but global
// variables make have had flowvars added in a previous function, and it's
// easier to just clear them all.
// This is done before .return and .param so they won't get reset just
// after being counted
for (i = 0; i < func->num_statements; i++) {
s = func->statements[i];
flow_analyze_statement (s, 0, 0, 0, operands);
for (j = 0; j < FLOW_OPERANDS; j++) {
if (operands[j] && operands[j]->op_type == op_def) {
def_visit_all (operands[j]->o.def, 0,
flow_def_clear_flowvars, 0);
}
}
}
// count .return and .param_[0-7] as they are always needed
for (i = 0; i < num_flow_params; i++) {
def_t *def = param_symbol (flow_params[i].name)->s.def;
def_t *a;
for (a = def->alias_defs; a; a = a->next) {
if (a->flowvar) {
delete_flowvar (a->flowvar);
a->flowvar = 0;
}
//free_def (def->alias_defs);
}
def_visit_all (def, 0, flow_def_clear_flowvars, 0);
flow_params[i].op.o.def = def;
num_vars += count_operand (&flow_params[i].op);
}