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Fix register corruption at function call on ARM 

Prior to this commit, params could use some registers that do not appear
in the value stack. Therefore when generating function call, one of such
register could be reused, leading to wrong parameter content. This
happens when a structure is passed via core register, as only the first
register would appear in the value stack.
master
Thomas Preud'homme 2013-11-21 21:09:44 +08:00
parent 1b606d1884
commit 41ce391c86
1 changed files with 16 additions and 6 deletions
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22
arm-gen.c
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@ -979,10 +979,12 @@ static int assign_regs(int nb_args, int variadic, struct plan *plan, int *todo)
nb_args: number of parameters the function take
plan: the overall assignment plan for parameters
todo: a bitmap indicating what core reg will hold a parameter */
static void copy_params(int nb_args, struct plan *plan, int todo)
todo: a bitmap indicating what core reg will hold a parameter
Returns the number of SValue added by this function on the value stack */
static int copy_params(int nb_args, struct plan *plan, int todo)
{
int size, align, r, i;
int size, align, r, i, nb_extra_sval = 0;
struct param_plan *pplan;
/* Several constraints require parameters to be copied in a specific order:
@ -1111,11 +1113,19 @@ static void copy_params(int nb_args, struct plan *plan, int todo)
if(todo) {
o(0xE8BD0000|todo); /* pop {todo} */
for(pplan = plan->clsplans[CORE_STRUCT_CLASS]; pplan; pplan = pplan->prev) {
int r;
pplan->sval->r = pplan->start;
if ((pplan->sval->type.t & VT_BTYPE) == VT_LLONG)
pplan->sval->r2 = pplan->end;
/* TODO: why adding fake param */
for (r = pplan->start + 1; r <= pplan->end; r++) {
if (todo & (1 << r)) {
nb_extra_sval++;
vpushi(0);
vtop->r = r;
}
}
}
}
return nb_extra_sval;
}
/* Generate function call. The function address is pushed first, then
@ -1158,7 +1168,7 @@ void gfunc_call(int nb_args)
}
#endif
copy_params(nb_args, &plan, todo);
nb_args += copy_params(nb_args, &plan, todo);
tcc_free(plan.pplans);
/* Move fct SValue on top as required by gcall_or_jmp */