From 7c6f271296319576fa00587928e5ff52ced9c1bb Mon Sep 17 00:00:00 2001 From: Simon Marchi Date: Sun, 12 Jul 2020 22:58:51 -0400 Subject: [PATCH] gdb: make get_discrete_bounds check for non-constant range bounds The next patch adds getters to the `dynamic_prop` structure. These getters validate that the accessed data matches the property kind (for example, to access the `const_val` field, the property must be of kind `PROP_CONST`). It found one instance where we are accessing the `const_val` data of a property that has the undefined kind. This happens in function `get_discrete_bounds`, and is exposed by test gdb.base/ptype.exp, amongst others. Without this patch, we would get: $ ./gdb -q -nx --data-directory=data-directory testsuite/outputs/gdb.base/ptype/ptype -ex "ptype t_char_array" Reading symbols from testsuite/outputs/gdb.base/ptype/ptype... type = char [ /home/smarchi/src/binutils-gdb/gdb/gdbtypes.h:526: internal-error: LONGEST dynamic_prop::const_val() const: Assertion `m_kind == PROP_CONST' failed. A problem internal to GDB has been detected, further debugging may prove unreliable. Quit this debugging session? (y or n) The `get_discrete_bounds` function returns the bounds of a type (not only range types). For range types, it naturally uses the bound properties that are intrinsic to the range type. It accesses these properties using TYPE_LOW_BOUND and TYPE_HIGH_BOUND, which assume the properties are defined and have constant values. This is sometimes not the case, and the passed range type (as in the example above) has an undefined high/upper bound. Given its current interface (returning two LONGEST values for low and high), `get_discrete_bounds` can't really work if the range type's bounds are not both defined and both constant values. This patch changes the function to return -1 (failure to get the bounds) if any of the range type's bounds is not a constant value. It is sufficient to fix the issue and it seems to keep the callers happy, at least according to the testsuite. A bit in `get_array_bounds` could be removed, since `get_discrete_bounds` no longer returns 1 if a bound is undefined. gdb/ChangeLog: * gdbtypes.c (get_discrete_bounds): Return failure if the range type's bounds are not both defined and constant values. (get_array_bounds): Update comment. Remove undefined bound check. Change-Id: I047a3beee2c1e275f888cfc4778228339922bde9 --- gdb/ChangeLog | 7 +++++++ gdb/gdbtypes.c | 29 +++++++++++++---------------- 2 files changed, 20 insertions(+), 16 deletions(-) diff --git a/gdb/ChangeLog b/gdb/ChangeLog index 90168a3d01..162929f414 100644 --- a/gdb/ChangeLog +++ b/gdb/ChangeLog @@ -1,3 +1,10 @@ +2020-07-12 Simon Marchi + + * gdbtypes.c (get_discrete_bounds): Return failure if + the range type's bounds are not both defined and constant + values. + (get_array_bounds): Update comment. Remove undefined bound check. + 2020-07-12 Simon Marchi * gdbtypes.h (TYPE_RANGE_DATA): Remove. Update callers to use diff --git a/gdb/gdbtypes.c b/gdb/gdbtypes.c index 957307ec61..40165563b9 100644 --- a/gdb/gdbtypes.c +++ b/gdb/gdbtypes.c @@ -1028,8 +1028,11 @@ has_static_range (const struct range_bounds *bounds) /* Set *LOWP and *HIGHP to the lower and upper bounds of discrete type - TYPE. Return 1 if type is a range type, 0 if it is discrete (and - bounds will fit in LONGEST), or -1 otherwise. */ + TYPE. + + Return 1 if type is a range type with two defined, constant bounds. + Else, return 0 if it is discrete (and bounds will fit in LONGEST). + Else, return -1. */ int get_discrete_bounds (struct type *type, LONGEST *lowp, LONGEST *highp) @@ -1038,8 +1041,15 @@ get_discrete_bounds (struct type *type, LONGEST *lowp, LONGEST *highp) switch (type->code ()) { case TYPE_CODE_RANGE: + /* This function currently only works for ranges with two defined, + constant bounds. */ + if (type->bounds ()->low.kind () != PROP_CONST + || type->bounds ()->high.kind () != PROP_CONST) + return -1; + *lowp = TYPE_LOW_BOUND (type); *highp = TYPE_HIGH_BOUND (type); + if (TYPE_TARGET_TYPE (type)->code () == TYPE_CODE_ENUM) { if (!discrete_position (TYPE_TARGET_TYPE (type), *lowp, lowp) @@ -1107,14 +1117,7 @@ get_discrete_bounds (struct type *type, LONGEST *lowp, LONGEST *highp) Save the high bound into HIGH_BOUND if not NULL. Return 1 if the operation was successful. Return zero otherwise, - in which case the values of LOW_BOUND and HIGH_BOUNDS are unmodified. - - We now simply use get_discrete_bounds call to get the values - of the low and high bounds. - get_discrete_bounds can return three values: - 1, meaning that index is a range, - 0, meaning that index is a discrete type, - or -1 for failure. */ + in which case the values of LOW_BOUND and HIGH_BOUNDS are unmodified. */ int get_array_bounds (struct type *type, LONGEST *low_bound, LONGEST *high_bound) @@ -1131,12 +1134,6 @@ get_array_bounds (struct type *type, LONGEST *low_bound, LONGEST *high_bound) if (res == -1) return 0; - /* Check if the array bounds are undefined. */ - if (res == 1 - && ((low_bound && TYPE_ARRAY_LOWER_BOUND_IS_UNDEFINED (type)) - || (high_bound && TYPE_ARRAY_UPPER_BOUND_IS_UNDEFINED (type)))) - return 0; - if (low_bound) *low_bound = low; -- 2.34.1