diff --git a/tools/perf/util/dwarf-aux.c b/tools/perf/util/dwarf-aux.c index 920054425578..449bc9ad7aff 100644 --- a/tools/perf/util/dwarf-aux.c +++ b/tools/perf/util/dwarf-aux.c @@ -1423,6 +1423,34 @@ static bool match_var_offset(Dwarf_Die *die_mem, struct find_var_data *data, return true; } +/** + * is_breg_access_indirect - Check if breg based access implies type + * dereference + * @ops: DWARF operations array + * @nops: Number of operations in @ops + * + * Returns true if the DWARF expression evaluates to the variable's + * value, so the memory access on that register needs type dereference. + * Returns false if the expression evaluates to the variable's address. + * This is called after check_allowed_ops. + */ +static bool is_breg_access_indirect(Dwarf_Op *ops, size_t nops) +{ + /* only the base register */ + if (nops == 1) + return false; + + if (nops == 2 && ops[1].atom == DW_OP_stack_value) + return true; + + if (nops == 3 && (ops[1].atom == DW_OP_deref || + ops[1].atom == DW_OP_deref_size) && + ops[2].atom == DW_OP_stack_value) + return false; + /* unreachable, OP not supported */ + return false; +} + /* Only checks direct child DIEs in the given scope. */ static int __die_find_var_reg_cb(Dwarf_Die *die_mem, void *arg) { @@ -1451,7 +1479,7 @@ static int __die_find_var_reg_cb(Dwarf_Die *die_mem, void *arg) if (data->is_fbreg && ops->atom == DW_OP_fbreg && check_allowed_ops(ops, nops) && match_var_offset(die_mem, data, data->offset, ops->number, - /*is_pointer=*/false)) + is_breg_access_indirect(ops, nops))) return DIE_FIND_CB_END; /* Only match with a simple case */ @@ -1463,11 +1491,11 @@ static int __die_find_var_reg_cb(Dwarf_Die *die_mem, void *arg) /*is_pointer=*/true)) return DIE_FIND_CB_END; - /* Local variables accessed by a register + offset */ + /* variables accessed by a register + offset */ if (ops->atom == (DW_OP_breg0 + data->reg) && check_allowed_ops(ops, nops) && match_var_offset(die_mem, data, data->offset, ops->number, - /*is_pointer=*/false)) + is_breg_access_indirect(ops, nops))) return DIE_FIND_CB_END; } else { /* pointer variables saved in a register 32 or above */ @@ -1477,11 +1505,11 @@ static int __die_find_var_reg_cb(Dwarf_Die *die_mem, void *arg) /*is_pointer=*/true)) return DIE_FIND_CB_END; - /* Local variables accessed by a register + offset */ + /* variables accessed by a register + offset */ if (ops->atom == DW_OP_bregx && data->reg == ops->number && check_allowed_ops(ops, nops) && match_var_offset(die_mem, data, data->offset, ops->number2, - /*is_poitner=*/false)) + is_breg_access_indirect(ops, nops))) return DIE_FIND_CB_END; } }