Remove the `TYPE_FIELD_NAME` and `FIELD_NAME` macros, changing all the
call sites to use field::name directly.
Change-Id: I6900ae4e1ffab1396e24fb3298e94bf123826ca6
I noticed that pointer_type is declared in language.h and defined in
language.c. However, it really has to do with types, so it should
have been in gdbtypes.h all along.
This patch changes it to be a method on struct type. And, I went
through uses of TYPE_IS_REFERENCE and updated many spots to use the
new method as well. (I didn't update ones that were in arch-specific
code, as I couldn't readily test that.)
Fixing a bug where the value_copy function did not copy the stack data
and initialized members of the struct value. This is needed for the
next patch where the DWARF expression evaluator is changed to return a
single struct value object.
* value.c (value_copy): Change to also copy the stack data
and initialized members.
This commit was originally part of this patch series:
(v1): https://sourceware.org/pipermail/gdb-patches/2021-May/179357.html
(v2): https://sourceware.org/pipermail/gdb-patches/2021-June/180208.html
(v3): https://sourceware.org/pipermail/gdb-patches/2021-July/181028.html
However, that series is being held up in review, so I wanted to break
out some of the non-related fixes in order to get these merged.
This commit addresses two semi-related issues, both of which are
problems exposed by using 'set debug frame on'.
The first issue is in frame.c in get_prev_frame_always_1, and was
introduced by this commit:
commit a05a883fba
Date: Tue Jun 29 12:03:50 2021 -0400
gdb: introduce frame_debug_printf
This commit replaced fprint_frame with frame_info::to_string.
However, the former could handle taking a nullptr while the later, a
member function, obviously requires a non-nullptr in order to make the
function call. In one place we are not-guaranteed to have a
non-nullptr, and so, there is the possibility of triggering undefined
behaviour.
The second issue addressed in this commit has existed for a while in
GDB, and would cause this assertion:
gdb/frame.c:622: internal-error: frame_id get_frame_id(frame_info*): Assertion `fi->this_id.p != frame_id_status::COMPUTING' failed.
We attempt to get the frame_id for a frame while we are computing the
frame_id for that same frame.
What happens is that when GDB stops we create a frame_info object for
the sentinel frame (frame #-1) and then we attempt to unwind this
frame to create a frame_info object for frame #0.
In the test case used here to expose the issue we have created a
Python frame unwinder. In the Python unwinder we attemt to read the
program counter register.
Reading this register will initially create a lazy register value.
The frame-id stored in the lazy register value will be for the
sentinel frame (lazy register values hold the frame-id for the frame
from which the register will be unwound).
However, the Python unwinder does actually want to examine the value
of the program counter, and so the lazy register value is resolved
into a non-lazy value. This sends GDB into value_fetch_lazy_register
in value.c.
Now, inside this function, if 'set debug frame on' is in effect, then
we want to print something like:
frame=%d, regnum=%d(%s), ....
Where 'frame=%d' will be the relative frame level of the frame for
which the register is being fetched, so, in this case we would expect
to see 'frame=0', i.e. we are reading a register as it would be in
frame #0. But, remember, the lazy register value actually holds the
frame-id for frame #-1 (the sentinel frame).
So, to get the frame_info for frame #0 we used to call:
frame = frame_find_by_id (VALUE_FRAME_ID (val));
Where VALUE_FRAME_ID is:
#define VALUE_FRAME_ID(val) (get_prev_frame_id_by_id (VALUE_NEXT_FRAME_ID (val)))
That is, we start with the frame-id for the next frame as obtained by
VALUE_NEXT_FRAME_ID, then call get_prev_frame_id_by_id to get the
frame-id of the previous frame.
The get_prev_frame_id_by_id function finds the frame_info for the
given frame-id (in this case frame #-1), calls get_prev_frame to get
the previous frame, and then calls get_frame_id.
The problem here is that calling get_frame_id requires that we know
the frame unwinder, so then have to try each frame unwinder in turn,
which would include the Python unwinder.... which is where we started,
and thus we have a loop!
To prevent this loop GDB has an assertion in place, which is what
actually triggers.
Solving the assertion failure is pretty easy, if we consider the code
in value_fetch_lazy_register and get_prev_frame_id_by_id then what we
do is:
1. Start with a frame_id taken from a value,
2. Lookup the corresponding frame,
3. Find the previous frame,
4. Get the frame_id for that frame, and
5. Lookup the corresponding frame
6. Print the frame's level
Notice that steps 3 and 5 give us the exact same result, step 4 is
just wasted effort. We could shorten this process such that we drop
steps 4 and 5, thus:
1. Start with a frame_id taken from a value,
2. Lookup the corresponding frame,
3. Find the previous frame,
6. Print the frame's level
This will give the exact same frame as a result, and this is what I
have done in this patch by removing the use of VALUE_FRAME_ID from
value_fetch_lazy_register.
Out of curiosity I looked to see how widely VALUE_FRAME_ID was used,
and saw it was only used in one other place in valops.c:value_assign,
where, once again, we take the result of VALUE_FRAME_ID and pass it to
frame_find_by_id, thus introducing a redundant frame_id lookup.
I don't think the value_assign case risks triggering the assertion
though, as we are unlikely to call value_assign while computing the
frame_id for a frame, however, we could make value_assign slightly
more efficient, with no real additional complexity, by removing the
use of VALUE_FRAME_ID.
So, in this commit, I completely remove VALUE_FRAME_ID, and replace it
with a use of VALUE_NEXT_FRAME_ID, followed by a direct call to
get_prev_frame_always, this should make no difference in either case,
and resolves the assertion issue from value.c.
As I said, this patch was originally part of another series, the
original test relied on the fixes in that original series. However, I
was able to create an alternative test for this issue by enabling
frame debug within an existing test script.
This commit probably fixes bug PR gdb/27938, though the bug doesn't
have a reproducer attached so it is not possible to know for sure.
Bug: https://sourceware.org/bugzilla/show_bug.cgi?id=27938
Introduce frame_debug_printf, to convert the "frame" debug messages to
the new system. Replace fprint_frame with a frame_info::to_string
method that returns a string, like what was done with
frame_id::to_string. This makes it easier to use with
frame_debug_printf.
gdb/ChangeLog:
* frame.h (frame_debug_printf): New.
* frame.c: Use frame_debug_printf throughout when printing frame
debug messages.
* amd64-windows-tdep.c: Likewise.
* value.c: Likewise.
gdb/testsuite/ChangeLog:
* gdb.dwarf2/dw2-reg-undefined.exp: Update regexp.
Change-Id: I3c230b0814ea81c23af3e1aca1aac8d4ba91d726
Same idea as previous patch, but for add_alias_cmd. Remove the overload
that accepts the target command as a string (the target command name),
leaving only the one that takes the cmd_list_element.
gdb/ChangeLog:
* command.h (add_alias_cmd): Accept target as
cmd_list_element. Update callers.
Change-Id: I546311f411e9e7da9302322d6ffad4e6c56df266
Previously, the prefixname field of struct cmd_list_element was manually
set for prefix commands. This seems verbose and error prone as it
required every single call to functions adding prefix commands to
specify the prefix name while the same information can be easily
generated.
Historically, this was not possible as the prefix field was null for
many commands, but this was fixed in commit
3f4d92ebdf by Philippe Waroquiers, so
we can rely on the prefix field being set when generating the prefix
name.
This commit also fixes a use after free in this scenario:
* A command gets created via Python (using the gdb.Command class).
The prefix name member is dynamically allocated.
* An alias to the new command is created. The alias's prefixname is set
to point to the prefixname for the original command with a direct
assignment.
* A new command with the same name as the Python command is created.
* The object for the original Python command gets freed and its
prefixname gets freed as well.
* The alias is updated to point to the new command, but its prefixname
is not updated so it keeps pointing to the freed one.
gdb/ChangeLog:
* command.h (add_prefix_cmd): Remove the prefixname argument as
it can now be generated automatically. Update all callers.
(add_basic_prefix_cmd): Ditto.
(add_show_prefix_cmd): Ditto.
(add_prefix_cmd_suppress_notification): Ditto.
(add_abbrev_prefix_cmd): Ditto.
* cli/cli-decode.c (add_prefix_cmd): Ditto.
(add_basic_prefix_cmd): Ditto.
(add_show_prefix_cmd): Ditto.
(add_prefix_cmd_suppress_notification): Ditto.
(add_prefix_cmd_suppress_notification): Ditto.
(add_abbrev_prefix_cmd): Ditto.
* cli/cli-decode.h (struct cmd_list_element): Replace the
prefixname member variable with a method which generates the
prefix name at runtime. Update all code reading the prefix
name to use the method, and remove all code setting it.
* python/py-cmd.c (cmdpy_destroyer): Remove code to free the
prefixname member as it's now a method.
(cmdpy_function): Determine if the command is a prefix by
looking at prefixlist, not prefixname.
The current_top_target function is a hidden dependency on the current
inferior. Since I'd like to slowly move towards reducing our dependency
on the global current state, remove this function and make callers use
current_inferior ()->top_target ()
There is no expected change in behavior, but this one step towards
making those callers use the inferior from their context, rather than
refer to the global current inferior.
gdb/ChangeLog:
* target.h (current_top_target): Remove, make callers use the
current inferior instead.
* target.c (current_top_target): Remove.
Change-Id: Iccd457036f84466cdaa3865aa3f9339a24ea001d
When not parsing for completion, parse_expression ensures that the
resulting expression has operations. This patch removes a couple of
unnecessary checks for this situation.
gdb/ChangeLog
2021-03-08 Tom Tromey <tom@tromey.com>
* printcmd.c (set_command): Remove null check.
* value.c (init_if_undefined_command): Remove null check.
This adds an expr::operation_up to struct expression, and then
modifies various parts of GDB to use this member when it is non-null.
The list of such spots was a bit surprising to me, and found only
after writing most of the code and then noticing what no longer
compiled.
In a few spots, new accessor methods are added to operation
subclasses, so that code that dissects an expression will work with
the new scheme.
After this change, code that constructs an expression can be switched
to the new form without breaking.
gdb/ChangeLog
2021-03-08 Tom Tromey <tom@tromey.com>
* ada-exp.h (class ada_var_value_operation) <get_symbol>: Remove;
now in superclass.
* value.h (fetch_subexp_value): Add "op" parameter.
* value.c (init_if_undefined_command): Update.
* tracepoint.c (validate_actionline, encode_actions_1): Update.
* stap-probe.c (stap_probe::compile_to_ax): Update.
* printcmd.c (set_command): Update.
* ppc-linux-nat.c (ppc_linux_nat_target::check_condition):
Update.
* parser-defs.h (struct expr_builder) <set_operation>: New
method.
* parse.c (parse_exp_in_context, exp_uses_objfile): Update.
* expression.h (struct expression) <first_opcode>: Update.
<op>: New member.
* expprint.c (dump_raw_expression, dump_prefix_expression):
Update.
* expop.h (class var_value_operation) <get_symbol>: New method.
(class register_operation) <get_name>: New method.
(class equal_operation): No longer a typedef, now a subclass.
(class unop_memval_operation) <get_type>: New method.
(class assign_operation) <get_lhs>: New method.
(class unop_cast_operation) <get_type>: New method.
* eval.c (evaluate_expression, evaluate_type)
(evaluate_subexpression_type): Update.
(fetch_subexp_value): Add "op" parameter.
(parse_and_eval_type): Update.
* dtrace-probe.c (dtrace_probe::compile_to_ax): Update.
* breakpoint.c (update_watchpoint, watchpoint_check)
(watchpoint_exp_is_const, watch_command_1): Update.
* ax-gdb.c (gen_trace_for_expr, gen_eval_for_expr, gen_printf):
Update.
With a certain Ada program, ada-lang.c:coerce_unspec_val_to_type can
cause a crash. This function may copy a value, and in the particular
case in the crash, the new value's type is smaller than the original
type. This causes coerce_unspec_val_to_type to create a lazy value --
but the original value is also not_lval, so later, when the value is
un-lazied, gdb asserts.
As with the previous patch, we believe there is a compiler bug here,
but it is difficult to reproduce, so we're not completely certain.
In the particular case we saw, the original value has record type, and
the record holds some variable-length arrays. This leads to the
type's length being 0. At the same time, the value is optimized out.
This patch changes coerce_unspec_val_to_type to handle an
optimized-out value correctly.
It also slightly restructures this code to avoid a crash should a
not_lval value wind up here. This is a purely defensive change.
This change also made it clear that value_contents_copy_raw can now be
made static, so that is also done.
gdb/ChangeLog
2021-02-09 Tom Tromey <tromey@adacore.com>
* ada-lang.c (coerce_unspec_val_to_type): Avoid making lazy
not_lval value.
* value.c (value_contents_copy_raw): Now static.
* value.h (value_contents_copy_raw): Don't declare.
I think this makes the names of the methods clearer, especially for the
arch. The type::arch method (which gets the arch owner, or NULL if the
type is not arch owned) is easily confused with the get_type_arch method
(which returns an arch no matter what). The name "arch_owner" will make
it intuitive that the method returns NULL if the type is not arch-owned.
Also, this frees the type::arch name, so we will be able to morph the
get_type_arch function into the type::arch method.
gdb/ChangeLog:
* gdbtypes.h (struct type) <arch>: Rename to...
<arch_owner>: ... this, update all users.
<objfile>: Rename to...
<objfile_owner>: ... this, update all users.
Change-Id: Ie7c28684c7b565adec05a7619c418c69429bd8c0
Change all users to use the type::objfile method instead.
gdb/ChangeLog:
* gdbtypes.h (TYPE_OBJFILE): Remove, change all users to use the
type::objfile method instead.
Change-Id: I6b3f580913fb1fb0cf986b176dba8db68e1fabf9
Consider this Fortran type:
type :: some_type
integer, allocatable :: array_one (:,:)
integer :: a_field
integer, allocatable :: array_two (:,:)
end type some_type
And a variable declared:
type(some_type) :: some_var
Now within GDB we try this:
(gdb) set $a = some_var
(gdb) p $a
$1 = ( array_one =
../../src/gdb/value.c:3968: internal-error: Unexpected lazy value type.
Normally, when an internalvar ($a in this case) is created, it is
non-lazy, the value is immediately copied out of the inferior into
GDB's memory.
When printing the internalvar ($a) GDB will extract each field in
turn, so in this case `array_one`. As the original internalvar is
non-lazy then the extracted field will also be non-lazy, with its
contents immediately copied from the parent internalvar.
However, when the field has a dynamic type this is not the case, in
value_primitive_field we see that any field with dynamic type is
always created lazy. Further, the content of this field will usually
not have been captured in the contents buffer of the original value, a
field with dynamic location is effectively a pointer value contained
within the parent value, with rules in the DWARF for how to
dereference the pointer.
So, we end up with a lazy lval_internalvar_component representing a
field within an lval_internalvar. This eventually ends up in
value_fetch_lazy, which currently does not support
lval_internalvar_component, and we see the error above.
My original plan for how to handle this involved extending
value_fetch_lazy to handle lval_internalvar_component. However, when
I did this I ran into another error:
(gdb) set $a = some_var
(gdb) p $a
$1 = ( array_one = ((1, 1) (1, 1) (1, 1)), a_field = 5, array_two = ((0, 0, 0) (0, 0, 0)) )
(gdb) p $a%array_one
$2 = ((1, 1) (1, 1) (1, 1))
(gdb) p $a%array_one(1,1)
../../src/gdb/value.c:1547: internal-error: void set_value_address(value*, CORE_ADDR): Assertion `value->lval == lval_memory' failed.
The problem now is inside set_value_component_location, where we
attempt to set the address for a component if the original parent
value has a dynamic location. GDB does not expect to ever set the
address on anything other than an lval_memory value (which seems
reasonable).
In order to resolve this issue I initially thought about how an
internalvar should "capture" the value of a program variable at the
moment the var is created. In an ideal world (I think) GDB would be
able to do this even for values with dynamic type. So in our above
example doing `set $a = some_var` would capture the content of
'some_var', but also the content of 'array_one', and also 'array_two',
even though these content regions are not contained within the region
of 'some_var'.
Supporting this would require GDB values to be able to carry around
multiple non-contiguous regions of memory as content in some way,
which sounds like a pretty huge change to a core part of GDB.
So, I wondered if there was some other solution that wouldn't require
such a huge change.
What if values with a dynamic location were though of like points with
automatic dereferencing? Given this C structure:
struct foo_t {
int *val;
}
struct foo_t my_foo;
Then in GDB:
(gdb) $a = my_foo
We would expect GDB to capture the pointer value in '$a', but not the
value pointed at by the pointer. So maybe it's not that unreasonable
to think that given a dynamically typed field GDB will capture the
address of the content, but not the actual content itself.
That's what this patch does.
The approach is to catch this case in set_value_component_location.
When we create a component location (of an lval_internalvar) that has
a dynamic data location, the lval_internalvar_component is changed
into an lval_memory. After this, both of the above issues are
resolved. In the first case, the lval_memory is still lazy, but
value_fetch_lazy knows how to handle that. In the second case, when
we access an element of the array we are now accessing an element of
an lval_memory, not an lval_internalvar_component, and calling
set_value_address on an lval_memory is fine.
gdb/ChangeLog:
* value.c (set_value_component_location): Adjust the VALUE_LVAL
for internalvar components that have a dynamic location.
gdb/testsuite/ChangeLog:
* gdb.fortran/intvar-dynamic-types.exp: New file.
* gdb.fortran/intvar-dynamic-types.f90: New file.
This commits the result of running gdb/copyright.py as per our Start
of New Year procedure...
gdb/ChangeLog
Update copyright year range in copyright header of all GDB files.
This adds a new helper method, expression::first_opcode, that extracts
the outermost opcode of an expression. This simplifies some patches
in the expression rewrite series.
Note that this patch requires the earlier patch to avoid manual
dissection of OP_TYPE operations.
2020-12-15 Tom Tromey <tom@tromey.com>
* varobj.c (varobj_create): Use first_opcode.
* value.c (init_if_undefined_command): Use first_opcode.
* typeprint.c (whatis_exp): Use first_opcode.
* tracepoint.c (validate_actionline): Use first_opcode.
(encode_actions_1): Use first_opcode.
* stack.c (return_command): Use first_opcode.
* expression.h (struct expression) <first_opcode>: New method.
* eval.c (parse_and_eval_type): Use first_opcode.
* dtrace-probe.c (dtrace_process_dof_probe): Use first_opcode.
I noticed that value_internal_function_name should have a const return
type. This patch makes this change.
gdb/ChangeLog
2020-12-04 Tom Tromey <tromey@adacore.com>
* value.c (value_internal_function_name): Make return type const.
* value.h (value_internal_function_name): Make return type const.
This logically connects this function to the object it inspects.
gdb/ChangeLog:
* gdbtypes.h (struct type) <fixed_point_scaling_factor>: New method,
replacing fixed_point_scaling_factor. All callers updated
throughout this project.
(fixed_point_scaling_factor): Delete declaration.
* gdbtypes.c (type::fixed_point_scaling_factor): Replaces
fixed_point_scaling_factor. Adjust implementation accordingly.
As suggested by Simon, to logically connect this function to
the object it inspects.
Note that, logically, this method should be "const". Unfortunately,
the implementation iterates on struct type objects starting with "this",
and thus trying to declare the method "const" triggers a compilation
error.
gdb/ChangeLog:
* gdbtypes.h (struct type) <fixed_point_type_base_type> New method,
replacing the fixed_point_type_base_type function. All callers
updated throughout this project.
(fixed_point_type_base_type): Remove declaration.
* gdbtypes.c (type::fixed_point_type_base_type): Replaces
fixed_point_type_base_type. Adjust implementation accordingly.
This commit changes the interfaces of some of the methods declared
in gmp-utils to take a gdb::array_view of gdb_byte instead of a
(gdb_byte *, size) couple.
This makes these methods' API probably more C++-idiomatic.
* gmp-utils.h (gdb_mpz::read): Change buf and len parameters
into one single gdb::array_view parameter.
(gdb_mpz::write): Likewise.
(gdb_mpq::read_fixed_point, gdb_mpq::write_fixed_point): Likewise.
* gmp-utils.c (gdb_mpz::read): Change buf and len parameters
into one single gdb::array_view parameter.
Adjust implementation accordingly.
(gdb_mpz::write): Likewise.
(gdb_mpq::read_fixed_point, gdb_mpq::write_fixed_point): Likewise.
* unittests/gmp-utils-selftests.c: Adapt following changes above.
* valarith.c, valops.c, valprint.c, value.c: Likewise.
This commit introduces a new kind of type, meant to describe
fixed-point types, using a new code added specifically for
this purpose (TYPE_CODE_FIXED_POINT).
It then adds handling of fixed-point base types in the DWARF reader.
And finally, as a first step, this commit adds support for printing
the value of fixed-point type objects.
Note that this commit has a known issue: Trying to print the value
of a fixed-point object with a format letter (e.g. "print /x NAME")
causes the wrong value to be printed because the scaling factor
is not applied. Since the fix for this issue is isolated, and
this is not a regression, the fix will be made in a pach of its own.
This is meant to simplify review and archeology.
Also, other functionalities related to fixed-point type handling
(ptype, arithmetics, etc), will be added piecemeal as well, for
the same reasons (faciliate reviews and archeology). Related to this,
the testcase gdb.ada/fixed_cmp.exp is adjusted to compile the test
program with -fgnat-encodings=all, so as to force the use of GNAT
encodings, rather than rely on the compiler's default to use them.
The intent is to enhance this testcase to also test the pure DWARF
approach using -fgnat-encodings=minimal as soon as the corresponding
suport gets added in. Thus, the modification to the testcase is made
in a way that it prepares this testcase to be tested in both modes.
gdb/ChangeLog:
* ada-valprint.c (ada_value_print_1): Add fixed-point type handling.
* dwarf2/read.c (get_dwarf2_rational_constant)
(get_dwarf2_unsigned_rational_constant, finish_fixed_point_type)
(has_zero_over_zero_small_attribute): New functions.
read_base_type, set_die_type): Add fixed-point type handling.
* gdb-gdb.py.in: Add fixed-point type handling.
* gdbtypes.c: #include "gmp-utils.h".
(create_range_type, set_type_code): Add fixed-point type handling.
(init_fixed_point_type): New function.
(is_integral_type, is_scalar_type): Add fixed-point type handling.
(print_fixed_point_type_info): New function.
(recursive_dump_type, copy_type_recursive): Add fixed-point type
handling.
(fixed_point_type_storage): New typedef.
(fixed_point_objfile_key): New static global.
(allocate_fixed_point_type_info, is_fixed_point_type): New functions.
(fixed_point_type_base_type, fixed_point_scaling_factor): New
functions.
* gdbtypes.h: #include "gmp-utils.h".
(enum type_code) <TYPE_SPECIFIC_FIXED_POINT>: New enum.
(union type_specific) <fixed_point_info>: New field.
(struct fixed_point_type_info): New struct.
(INIT_FIXED_POINT_SPECIFIC, TYPE_FIXED_POINT_INFO): New macros.
(init_fixed_point_type, is_fixed_point_type)
(fixed_point_type_base_type, fixed_point_scaling_factor)
(allocate_fixed_point_type_info): Add declarations.
* valprint.c (generic_val_print_fixed_point): New function.
(generic_value_print): Add fixed-point type handling.
* value.c (value_as_address, unpack_long): Add fixed-point type
handling.
gdb/testsuite/ChangeLog:
* gdb.ada/fixed_cmp.exp: Force compilation to use -fgnat-encodings=all.
* gdb.ada/fixed_points.exp: Add fixed-point variables printing tests.
* gdb.ada/fixed_points/pck.ads, gdb.ada/fixed_points/pck.adb:
New files.
* gdb.ada/fixed_points/fixed_points.adb: Add use of package Pck.
* gdb.dwarf2/dw2-fixed-point.c, gdb.dwarf2/dw2-fixed-point.exp:
New files.
This changes internalvar_name to return a const char *.
gdb/ChangeLog
2020-11-10 Tom Tromey <tom@tromey.com>
* value.h (internalvar_name): Update.
* value.c (internalvar_name): Make return type const.
PR symtab/25470 points out that the Zig programming language allows
integers of various bit sizes (including zero), not just sizes that
are a multiple of 8.
This is supported in DWARF by applying both a byte size and a
DW_AT_bit_size.
This patch adds support for this feature to integer and boolean types.
Other base types are not handled -- for floating-point types, this
didn't seem to make sense, and for character types I didn't see much
need. (These can be added later if desired.)
I've also added support for DW_AT_data_bit_offset at the same time. I
don't know whether the Zig compiler requires this, but it was
described in the same section in the DWARF standard and was easy to
add.
A new test case is supplied, using the DWARF assembler.
gdb/ChangeLog
2020-09-23 Tom Tromey <tom@tromey.com>
PR symtab/25470:
* value.c (unpack_long, pack_long, pack_unsigned_long): Handle bit
offset and bit size.
* printcmd.c (print_scalar_formatted): Handle zero-length
integer.
(print_scalar_formatted): Use bit_size_differs_p.
* gdbtypes.h (enum type_specific_kind) <TYPE_SPECIFIC_INT>: New
constant.
(union type_specific): <int_stuff>: New member.
(struct type) <bit_size_differs_p, bit_size, bit_offset>: New
methods.
* gdbtypes.c (init_integer_type, init_boolean_type): Initialize
TYPE_SPECIFIC_FIELD.
(recursive_dump_type, copy_type_recursive): Update.
* dwarf2/read.c (read_base_type): Handle DW_AT_bit_size and
DW_AT_data_bit_offset.
gdb/testsuite/ChangeLog
2020-09-23 Tom Tromey <tom@tromey.com>
* gdb.dwarf2/intbits.exp: New file.
* gdb.dwarf2/intbits.c: New file.
Convert language_data::string_lower_bound member variable to a virtual
method language_defn::string_lower_bound.
Over all of the languages we currently support there are currently
only two values for the lower bound, 0 or 1. I noticed that in all
cases, if a language has C style arrays then the lower bound is 0,
otherwise the lower bound is 1. So the default for the virtual method
in language.h makes use of this, which means languages don't have to
worry about providing a string_lower_bound method at all.
Except for Modula2. This language is defined to not have C style
arrays, but has a string_lower_bound index of 0, this behaviour is
maintained after this commit by having Modula2 be the only language
that overrides the string_lower_bound method.
There should be no user visible changes after this commit.
gdb/ChangeLog:
* ada-lang.c (ada_language_data): Remove string_lower_bound
initializer.
* c-lang.c (c_language_data): Likewise.
(cplus_language_data): Likewise.
(asm_language_data): Likewise.
(minimal_language_data): Likewise.
* d-lang.c (d_language_data): Likewise.
* f-lang.c (f_language_data): Likewise.
* go-lang.c (go_language_data): Likewise.
* language.c (unknown_language_data): Likewise.
(auto_language_data): Likewise.
* language.h (language_data): Remove string_lower_bound field.
(language_defn::string_lower_bound): New member function.
* m2-lang.c (m2_language_data): Remove string_lower_bound
initializer.
(m2_language::string_lower_bound): New member function.
* objc-lang.c (objc_language_data): Remove string_lower_bound
initializer.
* opencl-lang.c (opencl_language_data): Likewise.
* p-lang.c (pascal_language_data): Likewise.
* rust-lang.c (rust_language_data): Likewise.
* valops.c (value_cstring): Update call to string_lower_bound.
(value_string): Likewise.
* value.c (allocate_repeated_value): Likewise.
During debugging of PR26362, it was noticed that the malloc size check
in check_type_length_before_alloc wasn't detecting an allocation attempt
of a huge amount of bytes, making GDB run into an internal error.
This happens because we're using an int to store a type's length. When the
type length is large enough, the int will overflow and the max_value_size
check won't work anymore.
The following patch fixes this by making the length variable a ULONGEST.
Printing statements were also updated to show the correct number of bytes.
gdb/ChangeLog:
2020-08-12 Luis Machado <luis.machado@linaro.org>
* value.c (check_type_length_before_alloc): Use ULONGEST to store a
type's length.
Use %s and pulongest to print the length.
After dereferencing a pointer (in value_ind) or following a
reference (in coerce_ref) we call readjust_indirect_value_type to
"fixup" the type of the resulting value object.
This fixup handles cases relating to the type of the resulting object
being different (a sub-class) of the original pointers target type.
If we encounter a pointer to a dynamic type then after dereferencing a
pointer (in value_ind) the type of the object created will have had
its dynamic type resolved. However, in readjust_indirect_value_type,
we use the target type of the original pointer to "fixup" the type of
the resulting value. In this case, the target type will be a dynamic
type, so the resulting value object, once again has a dynamic type.
This then triggers an assertion later within GDB.
The solution I propose here is that we call resolve_dynamic_type on
the pointer's target type (within readjust_indirect_value_type) so
that the resulting value is not converted back to a dynamic type.
The test case is based on the original test in the bug report.
gdb/ChangeLog:
PR fortran/23051
PR fortran/26139
* valops.c (value_ind): Pass address to
readjust_indirect_value_type.
* value.c (readjust_indirect_value_type): Make parameter
non-const, and add extra address parameter. Resolve original type
before using it.
* value.h (readjust_indirect_value_type): Update function
signature and comment.
gdb/testsuite/ChangeLog:
PR fortran/23051
PR fortran/26139
* gdb.fortran/class-allocatable-array.exp: New file.
* gdb.fortran/class-allocatable-array.f90: New file.
* gdb.fortran/pointer-to-pointer.exp: New file.
* gdb.fortran/pointer-to-pointer.f90: New file.
Remove it in favor of using type::bounds directly.
gdb/ChangeLog:
* gdbtypes.h (TYPE_RANGE_DATA): Remove. Update callers to use
the type::bounds method directly.
Change-Id: Id4fab22af0a94cbf505f78b01b3ee5b3d682fba2
Running the testsuite against an Asan-enabled build of GDB makes
gdb.base/multi-target.exp expose this bug.
scoped_restore_current_thread's ctor calls get_frame_id to record the
selected frame's ID to restore later. If the frame ID hasn't been
computed yet, it will be computed on the spot, and that will usually
require accessing the target's memory and registers, which requires
remote accesses. If the remote connection closes while we're
computing the frame ID, the remote target exits its inferiors,
unpushes itself, and throws a TARGET_CLOSE_ERROR error.
If that happens, GDB can currently crash, here:
> ==18555==ERROR: AddressSanitizer: heap-use-after-free on address 0x621004670aa8 at pc 0x0000007ab125 bp 0x7ffdecaecd20 sp 0x7ffdecaecd10
> READ of size 4 at 0x621004670aa8 thread T0
> #0 0x7ab124 in dwarf2_frame_this_id src/binutils-gdb/gdb/dwarf2/frame.c:1228
> #1 0x983ec5 in compute_frame_id src/binutils-gdb/gdb/frame.c:550
> #2 0x9841ee in get_frame_id(frame_info*) src/binutils-gdb/gdb/frame.c:582
> #3 0x1093faa in scoped_restore_current_thread::scoped_restore_current_thread() src/binutils-gdb/gdb/thread.c:1462
> #4 0xaee5ba in fetch_inferior_event(void*) src/binutils-gdb/gdb/infrun.c:3968
> #5 0xaa990b in inferior_event_handler(inferior_event_type, void*) src/binutils-gdb/gdb/inf-loop.c:43
> #6 0xea61b6 in remote_async_serial_handler src/binutils-gdb/gdb/remote.c:14161
> #7 0xefca8a in run_async_handler_and_reschedule src/binutils-gdb/gdb/ser-base.c:137
> #8 0xefcd23 in fd_event src/binutils-gdb/gdb/ser-base.c:188
> #9 0x15a7416 in handle_file_event src/binutils-gdb/gdbsupport/event-loop.cc:548
> #10 0x15a7c36 in gdb_wait_for_event src/binutils-gdb/gdbsupport/event-loop.cc:673
> #11 0x15a5dbb in gdb_do_one_event() src/binutils-gdb/gdbsupport/event-loop.cc:215
> #12 0xbfe62d in start_event_loop src/binutils-gdb/gdb/main.c:356
> #13 0xbfe935 in captured_command_loop src/binutils-gdb/gdb/main.c:416
> #14 0xc01d39 in captured_main src/binutils-gdb/gdb/main.c:1253
> #15 0xc01dc9 in gdb_main(captured_main_args*) src/binutils-gdb/gdb/main.c:1268
> #16 0x414ddd in main src/binutils-gdb/gdb/gdb.c:32
> #17 0x7f590110b82f in __libc_start_main ../csu/libc-start.c:291
> #18 0x414bd8 in _start (build/binutils-gdb/gdb/gdb+0x414bd8)
What happens is that above, we're in dwarf2_frame_this_id, just after
the dwarf2_frame_cache call. The "cache" variable that the
dwarf2_frame_cache function returned is already stale. It's been
released here, from within the dwarf2_frame_cache:
(top-gdb) bt
#0 reinit_frame_cache () at src/gdb/frame.c:1855
#1 0x00000000014ff7b0 in switch_to_no_thread () at src/gdb/thread.c:1301
#2 0x0000000000f66d3e in switch_to_inferior_no_thread (inf=0x615000338180) at src/gdb/inferior.c:626
#3 0x00000000012f3826 in remote_unpush_target (target=0x6170000c5900) at src/gdb/remote.c:5521
#4 0x00000000013097e0 in remote_target::readchar (this=0x6170000c5900, timeout=2) at src/gdb/remote.c:9137
#5 0x000000000130be4d in remote_target::getpkt_or_notif_sane_1 (this=0x6170000c5900, buf=0x6170000c5918, forever=0, expecting_notif=0, is_notif=0x0) at src/gdb/remote.c:9683
#6 0x000000000130c8ab in remote_target::getpkt_sane (this=0x6170000c5900, buf=0x6170000c5918, forever=0) at src/gdb/remote.c:9790
#7 0x000000000130bc0d in remote_target::getpkt (this=0x6170000c5900, buf=0x6170000c5918, forever=0) at src/gdb/remote.c:9623
#8 0x000000000130838e in remote_target::remote_read_bytes_1 (this=0x6170000c5900, memaddr=0x7fffffffcdc0, myaddr=0x6080000ad3bc "", len_units=64, unit_size=1, xfered_len_units=0x7fff6a29b9a0) at src/gdb/remote.c:8860
#9 0x0000000001308bd2 in remote_target::remote_read_bytes (this=0x6170000c5900, memaddr=0x7fffffffcdc0, myaddr=0x6080000ad3bc "", len=64, unit_size=1, xfered_len=0x7fff6a29b9a0) at src/gdb/remote.c:8987
#10 0x0000000001311ed1 in remote_target::xfer_partial (this=0x6170000c5900, object=TARGET_OBJECT_MEMORY, annex=0x0, readbuf=0x6080000ad3bc "", writebuf=0x0, offset=140737488342464, len=64, xfered_len=0x7fff6a29b9a0) at src/gdb/remote.c:10988
#11 0x00000000014ba969 in raw_memory_xfer_partial (ops=0x6170000c5900, readbuf=0x6080000ad3bc "", writebuf=0x0, memaddr=140737488342464, len=64, xfered_len=0x7fff6a29b9a0) at src/gdb/target.c:918
#12 0x00000000014bb720 in target_xfer_partial (ops=0x6170000c5900, object=TARGET_OBJECT_RAW_MEMORY, annex=0x0, readbuf=0x6080000ad3bc "", writebuf=0x0, offset=140737488342464, len=64, xfered_len=0x7fff6a29b9a0) at src/gdb/target.c:1148
#13 0x00000000014bc3b5 in target_read_partial (ops=0x6170000c5900, object=TARGET_OBJECT_RAW_MEMORY, annex=0x0, buf=0x6080000ad3bc "", offset=140737488342464, len=64, xfered_len=0x7fff6a29b9a0) at src/gdb/target.c:1380
#14 0x00000000014bc593 in target_read (ops=0x6170000c5900, object=TARGET_OBJECT_RAW_MEMORY, annex=0x0, buf=0x6080000ad3bc "", offset=140737488342464, len=64) at src/gdb/target.c:1419
#15 0x00000000014bbd4d in target_read_raw_memory (memaddr=0x7fffffffcdc0, myaddr=0x6080000ad3bc "", len=64) at src/gdb/target.c:1252
#16 0x0000000000bf27df in dcache_read_line (dcache=0x6060001eddc0, db=0x6080000ad3a0) at src/gdb/dcache.c:336
#17 0x0000000000bf2b72 in dcache_peek_byte (dcache=0x6060001eddc0, addr=0x7fffffffcdd8, ptr=0x6020001231b0 "") at src/gdb/dcache.c:403
#18 0x0000000000bf3103 in dcache_read_memory_partial (ops=0x6170000c5900, dcache=0x6060001eddc0, memaddr=0x7fffffffcdd8, myaddr=0x6020001231b0 "", len=8, xfered_len=0x7fff6a29bf20) at src/gdb/dcache.c:484
#19 0x00000000014bafe9 in memory_xfer_partial_1 (ops=0x6170000c5900, object=TARGET_OBJECT_STACK_MEMORY, readbuf=0x6020001231b0 "", writebuf=0x0, memaddr=140737488342488, len=8, xfered_len=0x7fff6a29bf20) at src/gdb/target.c:1034
#20 0x00000000014bb212 in memory_xfer_partial (ops=0x6170000c5900, object=TARGET_OBJECT_STACK_MEMORY, readbuf=0x6020001231b0 "", writebuf=0x0, memaddr=140737488342488, len=8, xfered_len=0x7fff6a29bf20) at src/gdb/target.c:1076
#21 0x00000000014bb6b3 in target_xfer_partial (ops=0x6170000c5900, object=TARGET_OBJECT_STACK_MEMORY, annex=0x0, readbuf=0x6020001231b0 "", writebuf=0x0, offset=140737488342488, len=8, xfered_len=0x7fff6a29bf20) at src/gdb/target.c:1133
#22 0x000000000164564d in read_value_memory (val=0x60f000029440, bit_offset=0, stack=1, memaddr=0x7fffffffcdd8, buffer=0x6020001231b0 "", length=8) at src/gdb/valops.c:956
#23 0x0000000001680fff in value_fetch_lazy_memory (val=0x60f000029440) at src/gdb/value.c:3764
#24 0x0000000001681efd in value_fetch_lazy (val=0x60f000029440) at src/gdb/value.c:3910
#25 0x0000000001676143 in value_optimized_out (value=0x60f000029440) at src/gdb/value.c:1411
#26 0x0000000000e0fcb8 in frame_register_unwind (next_frame=0x6210066bfde0, regnum=16, optimizedp=0x7fff6a29c200, unavailablep=0x7fff6a29c240, lvalp=0x7fff6a29c2c0, addrp=0x7fff6a29c300, realnump=0x7fff6a29c280, bufferp=0x7fff6a29c3a0 "@\304)j\377\177") at src/gdb/frame.c:1144
#27 0x0000000000e10418 in frame_unwind_register (next_frame=0x6210066bfde0, regnum=16, buf=0x7fff6a29c3a0 "@\304)j\377\177") at src/gdb/frame.c:1196
#28 0x0000000000f00431 in i386_unwind_pc (gdbarch=0x6210043d0110, next_frame=0x6210066bfde0) at src/gdb/i386-tdep.c:1969
#29 0x0000000000e39724 in gdbarch_unwind_pc (gdbarch=0x6210043d0110, next_frame=0x6210066bfde0) at src/gdb/gdbarch.c:3056
#30 0x0000000000c2ea90 in dwarf2_tailcall_sniffer_first (this_frame=0x6210066bfde0, tailcall_cachep=0x6210066bfee0, entry_cfa_sp_offsetp=0x0) at src/gdb/dwarf2/frame-tailcall.c:423
#31 0x0000000000c36bdb in dwarf2_frame_cache (this_frame=0x6210066bfde0, this_cache=0x6210066bfdf8) at src/gdb/dwarf2/frame.c:1198
#32 0x0000000000c36eb3 in dwarf2_frame_this_id (this_frame=0x6210066bfde0, this_cache=0x6210066bfdf8, this_id=0x6210066bfe40) at src/gdb/dwarf2/frame.c:1226
Note that remote_target::readchar in frame #4 throws
TARGET_CLOSE_ERROR after the remote_unpush_target in frame #3 returns.
The problem is that the TARGET_CLOSE_ERROR is swallowed by
value_optimized_out in frame #25.
If we fix that one, then we run into dwarf2_tailcall_sniffer_first
swallowing the exception in frame #30 too.
The attached patch fixes it by making those spots swallow fewer kinds
of errors.
gdb/ChangeLog:
* frame-tailcall.c (dwarf2_tailcall_sniffer_first): Only swallow
NO_ENTRY_VALUE_ERROR / MEMORY_ERROR / OPTIMIZED_OUT_ERROR /
NOT_AVAILABLE_ERROR.
* value.c (value_optimized_out): Only swallow MEMORY_ERROR /
OPTIMIZED_OUT_ERROR / NOT_AVAILABLE_ERROR.
Remove the `TYPE_FIELD_TYPE` macro, changing all the call sites to use
`type::field` and `field::type` directly.
gdb/ChangeLog:
* gdbtypes.h (TYPE_FIELD_TYPE): Remove. Change all call sites
to use type::field and field::type instead.
Change-Id: Ifda6226a25c811cfd334a756a9fbc5c0afdddff3
Remove `TYPE_NAME`, changing all the call sites to use `type::name`
directly. This is quite a big diff, but this was mostly done using sed
and coccinelle. A few call sites were done by hand.
gdb/ChangeLog:
* gdbtypes.h (TYPE_NAME): Remove. Change all cal sites to use
type::name instead.
Remove TYPE_CODE, changing all the call sites to use type::code
directly. This is quite a big diff, but this was mostly done using sed
and coccinelle. A few call sites were done by hand.
gdb/ChangeLog:
* gdbtypes.h (TYPE_CODE): Remove. Change all call sites to use
type::code instead.
Move remove_dyn_prop, currently a free function, to be a method of
struct type.
gdb/ChangeLog:
* gdbtypes.h (struct type) <remove_dyn_prop>: New method.
(remove_dyn_prop): Remove. Update all users to use
type::remove_dyn_prop.
* gdbtypes.c (remove_dyn_prop): Rename to...
(type::remove_dyn_prop): ... this.
When evaluating a DWARF expression, the dynamic type resolution code
will pass in a buffer of bytes via the property_addr_info. However,
the DWARF expression evaluator will then proceed to read memory from
the inferior, even when the request could be filled from this buffer.
This, in turn, is a problem in some cases; and specifically when
trying to handle the Ada scenario of extracting a variable-length
value from a packed array. Here, the ordinary DWARF expression cannot
be directly evaluated, because the data may appear at some arbitrary
bit offset. So, it is unpacked into a staging area and then the
expression is evaluated -- using an address of 0.
This patch fixes the problem by arranging for the DWARF evaluator, in
this case, to prefer passed-in memory when possible. The type of the
buffer in the property_addr_info is changed to an array_view so that
bounds checking can be done.
gdb/ChangeLog
2020-04-24 Tom Tromey <tromey@adacore.com>
* ada-lang.c (ada_discrete_type_high_bound, ada_discrete_type_low)
(ada_value_primitive_packed_val): Update.
* ada-valprint.c (ada_value_print_1): Update.
* dwarf2/loc.c (evaluate_for_locexpr_baton): New struct.
(dwarf2_locexpr_baton_eval): Take a property_addr_info rather than
just an address. Use evaluate_for_locexpr_baton.
(dwarf2_evaluate_property): Update.
* dwarf2/loc.h (struct property_addr_info) <valaddr>: Now an
array_view.
* findvar.c (default_read_var_value): Update.
* gdbtypes.c (compute_variant_fields_inner)
(resolve_dynamic_type_internal): Update.
(resolve_dynamic_type): Change type of valaddr parameter.
* gdbtypes.h (resolve_dynamic_type): Update.
* valarith.c (value_subscripted_rvalue): Update.
* value.c (value_from_contents_and_address): Update.
This patch adds the infrastructure for the new variant part code. At
this point, nothing uses this code. This is done in a separate patch
to make it simpler to review.
I examined a few possible approaches to handling variant parts. In
particular, I considered having a DWARF variant part be a union
(similar to how the Rust code works now); and I considered having type
fields have a flag indicating that they are variants.
Having separate types seemed bad conceptually, because these variants
aren't truly separate -- they rely on the "parent" type. And,
changing how fields worked seemed excessively invasive.
So, in the end I thought the approach taken in this patch was both
simple to implement and understand, without losing generality. The
idea in this patch is that all the fields of a type with variant parts
will be stored in a single field array, just as if they'd all been
listed directly. Then, the variants are attached as a dynamic
property. These control which fields end up in the type that's
constructed during dynamic type resolution.
gdb/ChangeLog
2020-04-24 Tom Tromey <tromey@adacore.com>
* gdbtypes.c (is_dynamic_type_internal): Check for variant parts.
(variant::matches, compute_variant_fields_recurse)
(compute_variant_fields_inner, compute_variant_fields): New
functions.
(resolve_dynamic_struct): Check for DYN_PROP_VARIANT_PARTS.
Use resolved_type after type is made.
(operator==): Add new cases.
* gdbtypes.h (TYPE_HAS_VARIANT_PARTS): New macro.
(struct discriminant_range, struct variant, struct variant_part):
New.
(union dynamic_prop_data) <variant_parts, original_type>: New
members.
(enum dynamic_prop_node_kind) <DYN_PROP_VARIANT_PARTS>: New constant.
(enum dynamic_prop_kind) <PROP_TYPE, PROP_VARIANT_PARTS>: New
constants.
* value.c (unpack_bits_as_long): Now public.
* value.h (unpack_bits_as_long): Declare.
This introduces two new functions that make it simpler to access the
components of a complex number.
gdb/ChangeLog
2020-04-01 Tom Tromey <tom@tromey.com>
* valprint.c (generic_value_print_complex): Use accessors.
* value.h (value_real_part, value_imaginary_part): Declare.
* valops.c (value_real_part, value_imaginary_part): New
functions.
* value.c (creal_internal_fn, cimag_internal_fn): Use accessors.
From what I can tell, set_gdbarch_bits_big_endian has never been used.
That is, all architectures since its introduction have simply used the
default, which is simply check the architecture's byte-endianness.
Because this interferes with the scalar_storage_order code, this patch
removes this gdbarch setting entirely. In some places,
type_byte_order is used rather than the plain gdbarch.
gdb/ChangeLog
2019-12-04 Tom Tromey <tromey@adacore.com>
* ada-lang.c (decode_constrained_packed_array)
(ada_value_assign, value_assign_to_component): Update.
* dwarf2loc.c (rw_pieced_value, access_memory)
(dwarf2_compile_expr_to_ax): Update.
* dwarf2read.c (dwarf2_add_field): Update.
* eval.c (evaluate_subexp_standard): Update.
* gdbarch.c, gdbarch.h: Rebuild.
* gdbarch.sh (bits_big_endian): Remove.
* gdbtypes.h (union field_location): Update comment.
* target-descriptions.c (make_gdb_type): Update.
* valarith.c (value_bit_index): Update.
* value.c (struct value) <bitpos>: Update comment.
(unpack_bits_as_long, modify_field): Update.
* value.h (value_bitpos): Update comment.
Change-Id: I379b5e0c408ec8742f7a6c6b721108e73ed1b018
I noticed that the comment before creal_internal_fn refers to $_cimag,
but should refer to $_creal.
gdb/ChangeLog
2019-11-28 Tom Tromey <tom@tromey.com>
* value.c (creal_internal_fn): Fix comment.
Change-Id: I5665aceb4be5aae7014e914cfb39db184c65d5ea
This adds a "name_allocated" field to cmd_list_element, so that
commands can own their "name" when necessary. Then, this changes a
few spots in gdb that currently free the name by hand to instead use
this facility.
gdb/ChangeLog
2019-11-26 Tom Tromey <tom@tromey.com>
* python/py-function.c (fnpy_init): Update.
* value.h (add_internal_function): Adjust declaration.
* value.c (function_destroyer): Remove.
(do_add_internal_function): Don't set destroyer or copy name.
(add_internal_function): Take unique_xmalloc_ptr<char> for name.
Set name_allocated.
* python/py-cmd.c (cmdpy_destroyer): Don't free "name".
(cmdpy_init): Set name_allocated.
* cli/cli-decode.h (struct cmd_list_element) <name_allocated>: New
member.
(~cmd_list_element): Free "name" if needed.
Change-Id: Ie1435cea5bbf4bd92056125f112917c607cbb761
add_internal_function sets a command destroyer that frees the doc
string. However, many callers do not pass in an allocated doc string.
This adds a new overload to clearly differentiate the two cases,
fixing the latent bug.
gdb/ChangeLog
2019-11-26 Tom Tromey <tom@tromey.com>
* value.h (add_internal_function): Add new overload. Move
documentation from value.h.
* value.c (do_add_internal_function): New function.
(add_internal_function): Use it. Add new overload.
(function_destroyer): Don't free doc.
* python/py-function.c (fnpy_init): Update.
Change-Id: I3f6df925bc6b3e1bccbad9eeebc487b908bb5a2a
- Rationale:
It is possible for compilers to indicate the desired byte order
interpretation of scalar variables using the DWARF attribute:
DW_AT_endianity
A type flagged with this variable would typically use one of:
DW_END_big
DW_END_little
which instructs the debugger what the desired byte order interpretation
of the variable should be.
The GCC compiler (as of V6) has a mechanism for setting the desired byte
ordering of the fields within a structure or union. For, example, on a
little endian target, a structure declared as:
struct big {
int v;
short a[4];
} __attribute__( ( scalar_storage_order( "big-endian" ) ) );
could be used to ensure all the structure members have a big-endian
interpretation (the compiler would automatically insert byte swap
instructions before and after respective store and load instructions).
- To reproduce
GCC V8 is required to correctly emit DW_AT_endianity DWARF attributes
in all situations when the scalar_storage_order attribute is used.
A fix for (dwarf endianity instrumentation) for GCC V6-V7 can be found
in the URL field of the following PR:
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=82509
- Test-case:
A new test case (testsuite/gdb.base/endianity.*) is included with this
patch.
Manual testing for mixed endianity code has also been done with GCC V8.
See:
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=82509#c4
- Observed vs. expected:
Without this change, using scalar_storage_order that doesn't match the
target, such as
struct otherendian
{
int v;
} __attribute__( ( scalar_storage_order( "big-endian" ) ) );
would behave like the following on a little endian target:
Breakpoint 1 at 0x401135: file endianity.c, line 41.
(gdb) run
Starting program: /home/pjoot/freeware/t/a.out
Missing separate debuginfos, use: debuginfo-install glibc-2.17-292.el7.x86_64
Breakpoint 1, main () at endianity.c:41
41 struct otherendian o = {3};
(gdb) n
43 do_nothing (&o); /* START */
(gdb) p o
$1 = {v = 50331648}
(gdb) p /x
$2 = {v = 0x3000000}
whereas with this gdb enhancement we can access the variable with the user
specified endianity:
Breakpoint 1, main () at endianity.c:41
41 struct otherendian o = {3};
(gdb) p o
$1 = {v = 0}
(gdb) n
43 do_nothing (&o); /* START */
(gdb) p o
$2 = {v = 3}
(gdb) p o.v = 4
$3 = 4
(gdb) p o.v
$4 = 4
(gdb) x/4xb &o.v
0x7fffffffd90c: 0x00 0x00 0x00 0x04
(observe that the 4 byte int variable has a big endian representation in the
hex dump.)
gdb/ChangeLog
2019-11-21 Peeter Joot <peeter.joot@lzlabs.com>
Byte reverse display of variables with DW_END_big, DW_END_little
(DW_AT_endianity) dwarf attributes if different than the native
byte order.
* ada-lang.c (ada_value_binop):
Use type_byte_order instead of gdbarch_byte_order.
* ada-valprint.c (printstr):
(ada_val_print_string):
* ada-lang.c (value_pointer):
(ada_value_binop):
Use type_byte_order instead of gdbarch_byte_order.
* c-lang.c (c_get_string):
Use type_byte_order instead of gdbarch_byte_order.
* c-valprint.c (c_val_print_array):
Use type_byte_order instead of gdbarch_byte_order.
* cp-valprint.c (cp_print_class_member):
Use type_byte_order instead of gdbarch_byte_order.
* dwarf2loc.c (rw_pieced_value):
Use type_byte_order instead of gdbarch_byte_order.
* dwarf2read.c (read_base_type): Handle DW_END_big,
DW_END_little
* f-lang.c (f_get_encoding):
Use type_byte_order instead of gdbarch_byte_order.
* findvar.c (default_read_var_value):
Use type_byte_order instead of gdbarch_byte_order.
* gdbtypes.c (check_types_equal):
Require matching TYPE_ENDIANITY_NOT_DEFAULT if set.
(recursive_dump_type): Print TYPE_ENDIANITY_BIG,
and TYPE_ENDIANITY_LITTLE if set.
(type_byte_order): new function.
* gdbtypes.h (TYPE_ENDIANITY_NOT_DEFAULT): New macro.
(struct main_type) <flag_endianity_not_default>:
New field.
(type_byte_order): New function.
* infcmd.c (default_print_one_register_info):
Use type_byte_order instead of gdbarch_byte_order.
* p-lang.c (pascal_printstr):
Use type_byte_order instead of gdbarch_byte_order.
* p-valprint.c (pascal_val_print):
Use type_byte_order instead of gdbarch_byte_order.
* printcmd.c (print_scalar_formatted):
Use type_byte_order instead of gdbarch_byte_order.
* solib-darwin.c (darwin_current_sos):
Use type_byte_order instead of gdbarch_byte_order.
* solib-svr4.c (solib_svr4_r_ldsomap):
Use type_byte_order instead of gdbarch_byte_order.
* stap-probe.c (stap_modify_semaphore):
Use type_byte_order instead of gdbarch_byte_order.
* target-float.c (target_float_same_format_p):
Use type_byte_order instead of gdbarch_byte_order.
* valarith.c (scalar_binop):
(value_bit_index):
Use type_byte_order instead of gdbarch_byte_order.
* valops.c (value_cast):
Use type_byte_order instead of gdbarch_byte_order.
* valprint.c (generic_emit_char):
(generic_printstr):
(val_print_string):
Use type_byte_order instead of gdbarch_byte_order.
* value.c (unpack_long):
(unpack_bits_as_long):
(unpack_value_bitfield):
(modify_field):
(pack_long):
(pack_unsigned_long):
Use type_byte_order instead of gdbarch_byte_order.
* findvar.c (unsigned_pointer_to_address):
(signed_pointer_to_address):
(unsigned_address_to_pointer):
(address_to_signed_pointer):
(default_read_var_value):
(default_value_from_register):
Use type_byte_order instead of gdbarch_byte_order.
* gnu-v3-abi.c (gnuv3_make_method_ptr):
Use type_byte_order instead of gdbarch_byte_order.
* riscv-tdep.c (riscv_print_one_register_info):
Use type_byte_order instead of gdbarch_byte_order.
gdb/testsuite/ChangeLog
2019-11-21 Peeter Joot <peeter.joot@lzlabs.com>
* gdb.base/endianity.c: New test.
* gdb.base/endianity.exp: New file.
Change-Id: I4bd98c1b4508c2d7c5a5dbb15d7b7b1cb4e667e2
Simon Marchi