From b49180acf205d8e52050cc05ca63f8f8630e7a9c Mon Sep 17 00:00:00 2001 From: Tom Tromey Date: Wed, 6 Jan 2021 13:47:48 -0700 Subject: Fix fixed-point binary operation type handling Testing showed that gdb was not correctly handling some fixed-point binary operations correctly. Addition and subtraction worked by casting the result to the type of left hand operand. So, "fixed+int" had a different type -- and different value -- from "int+fixed". Furthermore, for multiplication and division, it does not make sense to first cast both sides to the fixed-point type. For example, this can prevent "f * 1" from yielding "f", if 1 is not in the domain of "f". Instead, this patch changes gdb to use the value. (This is somewhat different from Ada semantics, as those can yield a "universal fixed point".) This includes a new test case. It is only run in "minimal" mode, as the old-style fixed point works differently, and is obsolete, so I have no plans to change it. gdb/ChangeLog 2021-01-06 Tom Tromey * ada-lang.c (ada_evaluate_subexp) : Do not cast result. * valarith.c (fixed_point_binop): Handle multiplication and division specially. * valops.c (value_to_gdb_mpq): New function. (value_cast_to_fixed_point): Use it. gdb/testsuite/ChangeLog 2021-01-06 Tom Tromey * gdb.ada/fixed_points/pck.ads (Delta4): New constant. (FP4_Type): New type. (FP4_Var): New variable. * gdb.ada/fixed_points/fixed_points.adb: Update. * gdb.ada/fixed_points.exp: Add tests for binary operators. --- gdb/valarith.c | 46 ++++++++++++++++++++++++++++++---------------- 1 file changed, 30 insertions(+), 16 deletions(-) (limited to 'gdb/valarith.c') diff --git a/gdb/valarith.c b/gdb/valarith.c index f3cc500..81d48aa 100644 --- a/gdb/valarith.c +++ b/gdb/valarith.c @@ -903,27 +903,41 @@ fixed_point_binop (struct value *arg1, struct value *arg2, enum exp_opcode op) struct gdbarch *gdbarch = get_type_arch (type1); struct value *val; + gdb_mpq v1, v2, res; + gdb_assert (is_fixed_point_type (type1) || is_fixed_point_type (type2)); - if (!is_fixed_point_type (type1)) + if (op == BINOP_MUL || op == BINOP_DIV) { - arg1 = value_cast (type2, arg1); - type1 = type2; + v1 = value_to_gdb_mpq (arg1); + v2 = value_to_gdb_mpq (arg2); + + /* The code below uses TYPE1 for the result type, so make sure + it is set properly. */ + if (!is_fixed_point_type (type1)) + type1 = type2; } - if (!is_fixed_point_type (type2)) + else { - arg2 = value_cast (type1, arg2); - type2 = type1; - } + if (!is_fixed_point_type (type1)) + { + arg1 = value_cast (type2, arg1); + type1 = type2; + } + if (!is_fixed_point_type (type2)) + { + arg2 = value_cast (type1, arg2); + type2 = type1; + } - gdb_mpq v1, v2, res; - v1.read_fixed_point (gdb::make_array_view (value_contents (arg1), - TYPE_LENGTH (type1)), - type_byte_order (type1), type1->is_unsigned (), - type1->fixed_point_scaling_factor ()); - v2.read_fixed_point (gdb::make_array_view (value_contents (arg2), - TYPE_LENGTH (type2)), - type_byte_order (type2), type2->is_unsigned (), - type2->fixed_point_scaling_factor ()); + v1.read_fixed_point (gdb::make_array_view (value_contents (arg1), + TYPE_LENGTH (type1)), + type_byte_order (type1), type1->is_unsigned (), + type1->fixed_point_scaling_factor ()); + v2.read_fixed_point (gdb::make_array_view (value_contents (arg2), + TYPE_LENGTH (type2)), + type_byte_order (type2), type2->is_unsigned (), + type2->fixed_point_scaling_factor ()); + } auto fixed_point_to_value = [type1] (const gdb_mpq &fp) { -- cgit v1.1