This patch changes type::fields to return an array_view of the fields,
then fixes up the fallout.
More cleanups would be possible here (in particular in the field
initialization code) but I haven't done so.
The main motivation for this patch was to make it simpler to iterate
over the fields of a type.
Regression tested on x86-64 Fedora 41.
Approved-By: Simon Marchi <simon.marchi@efficios.com>
In Ada, a field can have a dynamic bit offset in its enclosing record.
In DWARF 3, this was handled using a dynamic
DW_AT_data_member_location, combined with a DW_AT_bit_offset -- this
combination worked out ok because in practice GNAT only needs a
dynamic byte offset with a fixed offset within the byte.
However, this approach was deprecated in DWARF 4 and then removed in
DWARF 5. No replacement approach was given, meaning that in strict
mode there is no way to express this.
This is a DWARF bug, see
https://dwarfstd.org/issues/250501.1.html
In a discussion on the DWARF mailing list, a couple people mentioned
that compilers could use the obvious extension of a dynamic
DW_AT_data_bit_offset. I've implemented this for LLVM:
https://github.com/llvm/llvm-project/pull/141106
In preparation for that landing, this patch implements support for
this construct in gdb.
New in v2: renamed some constants and added a helper method, per
Simon's review.
New in v3: more renamings.
Approved-By: Simon Marchi <simon.marchi@efficios.com>
This patch makes a new function, apply_bit_offset_to_field, that is
used to handle the logic of DW_AT_bit_offset. Currently there is just
a single caller, but the next patch will change this.
I found a situation where gdb could not properly decode an Ada type.
In this first scenario, the discriminant of a type is a bit-field.
PROP_ADDR_OFFSET does not handle this situation, because it only
allows an offset -- not a bit-size.
My original approach to this just added a bit size as well, but after
some discussion with Eric Botcazou, we found another failing case: a
tagged type can have a second discriminant that appears at a variable
offset.
So, this patch changes this code to accept a general 'struct field'
instead of trying to replicate the field-finding machinery by itself.
This is handled at property-evaluation time by simply using a 'field'
and resolving its dynamic properties. Then the usual field-extraction
function is called to get the value.
Because the baton now just holds a field, I renamed PROP_ADDR_OFFSET
to PROP_FIELD.
The DWARF reader now defers filling in the property baton until the
fields have been attached to the type.
Finally, I noticed that if the discriminant field has a biased
representation, then unpack_field_as_long would not handle this
either. This bug is also fixed here, and the test case checks this.
Regression tested on x86-64 Fedora 41.
The final patch in this series will change one dynamic property
approach to use a struct field rather than an offset and a field type.
This is convenient because the reference in DWARF is indeed to a field
-- and this approach lets us reuse the field-extraction logic that
already exists in gdb.
However, the field in question may have dynamic properties which must
be resolved before it can be used. This patch prepares for this by
introducing a separate resolve_dynamic_field function.
This patch should cause no visible changes to behavior.
This updates the copyright headers to include 2025. I did this by
running gdb/copyright.py and then manually modifying a few files as
noted by the script.
Approved-By: Eli Zaretskii <eliz@gnu.org>
This scratches an itch I had for a while. I don't know why this struct
type has "data" in its name. Others like "dwarf2_per_objfile" and
"dwarf2_per_bfd" don't. The primary job of a structure is to hold data,
there's no need to specify it. It also makes the name a bit shorter,
which is always nice.
Rename related types too.
Change-Id: Ifb63195ff105809fc15b502f639c0bb4d18a675e
Approved-By: Tom Tromey <tom@tromey.com>
Reviewed-By: Guinevere Larsen <guinevere@redhat.com>
This patch is the result of running check-include-guards.py on the
current tree. Running it a second time causes no changes.
Reviewed-By: Tom de Vries <tdevries@suse.de>
The script in the next patch noticed some irregularities in some
headers: trailing or leading blank lines, or in one case a missing
copyright header. This patch fixes these.
Reviewed-By: Tom de Vries <tdevries@suse.de>
This converts the type copying code to use the new hash map.
Change-Id: I35f0a4946dcc5c5eb84820126cf716b600f3302f
Co-Authored-By: Tom Tromey <tom@tromey.com>
Approved-By: Tom Tromey <tom@tromey.com>
This patch makes allocate_on_obstack a little bit safer, by enforcing
the rule that objects allocated on an obstack must have a trivial
destructor.
The static assert is done in a method -- doing it inside the class
itself won't work because the class is incomplete at that point.
This changes some of the dynamic-type-related code to use bool rather
than int.
Regression tested on x86-64 Fedora 38.
Approved-By: John Baldwin <jhb@FreeBSD.org>
In Ada, sometimes the compiler must emit array bounds by referencing
an artificial variable that's created for this purpose. However, with
optimization enabled, these variables can be optimized away.
Currently this can result in displays like:
(gdb) print mumble
$1 = (warning: unable to get bounds of array, assuming null array
)
This patch changes this to report that the array is optimized-out,
instead, which is closer to the truth, and more generally useful. For
example, Python pretty-printers can now recognize this situation.
In order to accomplish this, I introduced a new PROP_OPTIMIZED_OUT
enumerator and changed one place to use it. Reusing the "unknown"
state wouldn't work properly, because in C it is normal for array
bounds to be unknown.
This commit is the result of the following actions:
- Running gdb/copyright.py to update all of the copyright headers to
include 2024,
- Manually updating a few files the copyright.py script told me to
update, these files had copyright headers embedded within the
file,
- Regenerating gdbsupport/Makefile.in to refresh it's copyright
date,
- Using grep to find other files that still mentioned 2023. If
these files were updated last year from 2022 to 2023 then I've
updated them this year to 2024.
I'm sure I've probably missed some dates. Feel free to fix them up as
you spot them.
Currently, it's not possible to call a variadic C++ function:
```
(gdb) print sum_vararg_int(1, 10)
Cannot resolve function sum_vararg_int to any overloaded instance
(gdb) print sum_vararg_int(2, 20, 30)
Cannot resolve function sum_vararg_int to any overloaded instance
```
It's because all additional arguments get the TOO_FEW_PARAMS_BADNESS
rank by rank_function, which disqualifies the function.
To fix this, I've created the new VARARG_BADNESS rank, which is
used only for additional arguments of variadic functions, allowing
them to be called:
```
(gdb) print sum_vararg_int(1, 10)
$1 = 10
(gdb) print sum_vararg_int(2, 20, 30)
$2 = 50
```
Bug: https://sourceware.org/bugzilla/show_bug.cgi?id=28589
Approved-By: Tom Tromey <tom@tromey.com>
A recent change to 'struct field' caused a build failure with GCC
7.5.0, as reported by Tom de Vries:
/data/vries/gdb/src/gdb/gdbtypes.h:721:51: error:
‘field::m_accessibility’ is too small to hold all values of ‘enum
class accessibility’ [-Werror]
ENUM_BITFIELD (accessibility) m_accessibility : 2;
^
Mark Wielaard pointed out that this was a GCC bug:
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=51242
This patch works around the bug by changing several members not to be
bitfields. It reduces the size of the enum's underlying type,
instead.
I also changed m_bitsize to no longer be a bitfield -- that was done
for packing reasons in ancient times, but with m_accessibility not
being a bitfield, this no longer matters.
I removed fn_field::dummy. In earlier times it was somewhat normal in
gdb to have these dummy fields to keep track of any available padding.
However, since the advent of "ptype/o", there doesn't seem to be any
need for this.
This patch does not change the size of struct field, fn_field, or
decl_field on 64-bit hosts.
This changes nested types and member functions to use the new
'accessibility' enum, rather than separate private/protected flags.
This is done for consistency, but it also lets us simplify some other
code in the next patch.
Acked-By: Simon Marchi <simon.marchi@efficios.com>
Reviewed-by: Keith Seitz <keiths@redhat.com>
This removes the char-based bitfield macros from gdbtypes.h, as they
are no longer used.
Acked-By: Simon Marchi <simon.marchi@efficios.com>
Reviewed-by: Keith Seitz <keiths@redhat.com>
This removes TYPE_FIELD_PRIVATE, TYPE_FIELD_PROTECTED,
TYPE_FIELD_IGNORE, and TYPE_FIELD_VIRTUAL.
In c-varobj.c, match_accessibility can be removed entirely now. Note
that the comment before this function was incorrect.
Acked-By: Simon Marchi <simon.marchi@efficios.com>
Reviewed-by: Keith Seitz <keiths@redhat.com>
This adds a field::is_public convenience method, and updates one spot
to use it.
Acked-By: Simon Marchi <simon.marchi@efficios.com>
Reviewed-by: Keith Seitz <keiths@redhat.com>
This removes some byte vectors from cplus_struct_type, moving the
information into bitfields in holes in struct field.
A new 'enum accessibility' is added to hold some of this information.
A similar enum is removed from c-varobj.c.
Note that the stabs reader treats "ignored" as an accessibility.
However, the stabs texinfo documents this as a public field that is
optimized out -- unfortunately nobody has updated the stabs reader to
use the better value-based optimized-out machinery. I looked and
apparently gcc never emitted this visibility value, so whatever
compiler generated this stab is unknown. I left a comment in
gdbtypes.h to this effect.
Acked-By: Simon Marchi <simon.marchi@efficios.com>
Reviewed-by: Keith Seitz <keiths@redhat.com>
Since GDB now requires C++17, we don't need the internally maintained
gdb::optional implementation. This patch does the following replacing:
- gdb::optional -> std::optional
- gdb::in_place -> std::in_place
- #include "gdbsupport/gdb_optional.h" -> #include <optional>
This change has mostly been done automatically. One exception is
gdbsupport/thread-pool.* which did not use the gdb:: prefix as it
already lives in the gdb namespace.
Change-Id: I19a92fa03e89637bab136c72e34fd351524f65e9
Approved-By: Tom Tromey <tom@tromey.com>
Approved-By: Pedro Alves <pedro@palves.net>
This changes main_type to hold a language, and updates the debug
readers to set this field. This is done by adding the language to the
type-allocator object.
Note that the non-DWARF readers are changed on a "best effort" basis.
This patch also reimplements type::is_array_like to use the type's
language, and it adds a new type::is_string_like as well. This in
turn lets us change the Python implementation of these methods to
simply defer to the type.
init_fixed_point_type currently takes an objfile and creates its own
type allocator. However, for a later patch it is more convenient if
this function accepts a type allocator. This patch makes this change.
This adds the type::is_array_like method and the value_to_array
function.
The former can be used to see whether a given type is known to be
"array-like". This is the currently the case for certain
compiler-generated structure types; in particular both the Ada and
Rust compilers do this.
This adds a new enum constant, TYPE_SPECIFIC_RUST_STUFF, and changes
the DWARF reader to set this on Rust types. This will be used as a
flag in a later patch.
Note that the size of the type_specific_field bitfield had to be
increased. I checked that this did not impact the size of main_type.
Replace with a new equivalent "is_packed" method on struct field.
Change-Id: I78647be3d408b40b63becb6b6f0fca211bede51c
Approved-By: Tom Tromey <tom@tromey.com>
Add these two methods, rename the field to m_bitsize to make it pseudo
private.
Change-Id: Ief95e5cf106e72f2c22ae47b033d0fa47202b413
Approved-By: Tom Tromey <tom@tromey.com>
Add these two methods, rename the field to m_artificial to make it
pseudo private.
Change-Id: If3a3825473d1d79bb586a8a074b87bba9b43fb1a
Approved-By: Tom Tromey <tom@tromey.com>
After finding this code in buildsym_compunit::finish_block_internal:
...
ftype->set_fields
((struct field *)
TYPE_ALLOC (ftype, nparams * sizeof (struct field)));
...
and fixing PR30810 by using TYPE_ZALLOC, I wondered if there were more
locations that needed fixing.
I decided to make things easier to spot by factoring out a new function
alloc_fields:
...
/* Allocate the fields array of this type, with NFIELDS elements. If INIT,
zero-initialize the allocated memory. */
void
type::alloc_fields (unsigned int nfields, bool init = true);
...
where:
- a regular use would be "alloc_fields (nfields)", and
- an exceptional use that needed no initialization would be
"alloc_fields (nfields, false)".
Pretty soon I discovered that most of the latter cases are due to
initialization by memcpy, so I added two variants of copy_fields as well.
After this rewrite there are 8 uses of set_fields left:
...
gdb/coffread.c: type->set_fields (nullptr);
gdb/coffread.c: type->set_fields (nullptr);
gdb/coffread.c: type->set_fields (nullptr);
gdb/eval.c: type->set_fields
gdb/gdbtypes.c: type->set_fields (args);
gdb/gdbtypes.c: t->set_fields (XRESIZEVEC (struct field, t->fields (),
gdb/dwarf2/read.c: type->set_fields (new_fields);
gdb/dwarf2/read.c: sub_type->set_fields (sub_type->fields () + 1);
...
These fall into the following categories:
- set to nullptr (coffread.c),
- type not owned by objfile or gdbarch (eval.c), and
- modifying an existing fields array, like adding an element at the end or
dropping an element at the start (the rest).
Tested on x86_64-linux.
Given this test program:
#include <wchar.h>
const wchar_t wide_str[] = L"wide string";
int
main (void)
{
return 0;
}
I observed this GDB behaviour:
$ gdb -q /tmp/printf-wchar_t
Reading symbols from /tmp/printf-wchar_t...
(gdb) start
Temporary breakpoint 1 at 0x40110a: file /tmp/printf-wchar_t.c, line 8.
Starting program: /tmp/printf-wchar_t
Temporary breakpoint 1, main () at /tmp/printf-wchar_t.c:8
25 return 0;
(gdb) printf "%ls\n", wide_str
(gdb)
Notice that the printf results in a blank line rather than the
expected 'wide string' output.
I tracked the problem down to printf_wide_c_string (in printcmd.c), in
this function we do this:
struct type *wctype = lookup_typename (current_language,
"wchar_t", NULL, 0);
int wcwidth = wctype->length ();
the problem here is that 'wchar_t' is a typedef. If we look at the
comment on type::length() we see this:
/* Note that if thistype is a TYPEDEF type, you have to call check_typedef.
But check_typedef does set the TYPE_LENGTH of the TYPEDEF type,
so you only have to call check_typedef once. Since value::allocate
calls check_typedef, X->type ()->length () is safe. */
What this means is that after calling lookup_typename we should call
check_typedef in order to ensure that the length of the typedef has
been setup correctly. We are not doing this in printf_wide_c_string,
and so wcwidth is incorrectly calculated as 0. This is what leads GDB
to print an empty string.
We can see in c_string_operation::evaluate (in c-lang.c) an example of
calling check_typedef specifically to fix this exact issue.
Initially I did fix this problem by adding a check_typedef call into
printf_wide_c_string, but then I figured why not move the
check_typedef call up into lookup_typename itself, that feels like it
should be harmless when looking up a non-typedef type, but will avoid
bugs like this when looking up a typedef. So that's what I did.
I can then remove the extra check_typedef call from c-lang.c, I don't
see any other places where we had extra check_typedef calls. This
doesn't mean we definitely had bugs -- so long as we never checked the
length, or, if we knew that check_typedef had already been called,
then we would be fine.
I don't see any test regressions after this change, and my new test
case is now passing.
Reviewed-By: Tom Tromey <tom@tromey.com>
I noticed many spots checking whether a dynamic property's kind is
PROP_CONST. Some spots, I think, are doing a slightly incorrect check
-- checking for != PROP_UNDEFINED where == PROP_CONST is actually
required, the key thing being that const_val may only be called for
PROP_CONST properties.
This patch adds dynamic::is_constant and then updates these checks to
use it.
Regression tested on x86-64 Fedora 36.
This changes field_is_static to be a method on struct field, and
updates all the callers. Most of this patch was written by script.
Regression tested on x86-64 Fedora 36.
This adds a frame parameter to resolve_dynamic_type and arranges for
it to be passed through the call tree and, in particular, to all calls
to dwarf2_evaluate_property.
Nothing passes this parameter yet, so this patch should have no
visible effect.
A 'const frame_info_ptr *' is used here to avoid including frame.h
from gdbtypes.h.
This adds some types to struct builtin_type, ensuring it contains all
the types currently used by objfile_type.
Reviewed-By: Simon Marchi <simon.marchi@efficios.com>
This renames objfile_type to be an overload of builtin_type, in
preparation for their unification.
Reviewed-By: Simon Marchi <simon.marchi@efficios.com>
This changes the set type creation function to accept a type
allocator, and updates all the callers. Note that symbol readers
should generally allocate on the relevant objfile, regardless of the
underlying type of the set, which is what this patch implements.
Reviewed-By: Simon Marchi <simon.marchi@efficios.com>
This changes the array type creation functions to accept a type
allocator, and updates all the callers. Note that symbol readers
should generally allocate on the relevant objfile, regardless of the
placement of the index type of the array, which is what this patch
implements.
Reviewed-By: Simon Marchi <simon.marchi@efficios.com>
This changes the range type creation functions to accept a type
allocator, and updates all the callers. Note that symbol readers
should generally allocate on the relevant objfile, regardless of the
underlying type of the range, which is what this patch implements.
Reviewed-By: Simon Marchi <simon.marchi@efficios.com>
