When a dynamic array type contains a typedef-wrapped array, an assertion
failure occurs during type resolution. This is what happens in the
following Ada case:
type Rec_Type is record
I : Integer;
B : Boolean;
end record;
type Vec_Type is array (1 .. 4) of Rec_Type;
type Array_Type is array (Positive range <>) of Vec_Type;
If users try to print or even pass to an inferior call a variable A of
type Array_Type, GDB will raise an error:
(gdb) print a
../../src/gdb/gdbtypes.c:1807: internal-error:
resolve_dynamic_array: Assertion `TYPE_CODE (type) ==
TYPE_CODE_ARRAY' failed.
A problem internal to GDB has been detected,
further debugging may prove unreliable.
Quit this debugging session? (y or n)
What happens is that during dynamic array type resolution, we first peel
TYPE_CODE_TYPEDEF layers wrapping the array element type and check if
its type is itself TYPE_CODE_ARRAY. If it is, we pass the
typedef-wrapped type to a recursive call to resolve_dynamic_array
whereas this function expects only TYPE_CODE_ARRAY types.
This patch makes it pass the peeled type to the recursive call so that
type resolution can continue smoothly.
gdb/ChangeLog:
* gdbtypes.c (resolve_dynamic_array): Pass the peeled element
type to the recursive call instead of the original (maybe
TYPE_CODE_TYPEDEF) type.
gdb/testsuite/ChangeLog:
* gdb.ada/var_arr_typedef.exp: New testcase.
* gdb.ada/var_arr_typedef/pack.adb: New file.
* gdb.ada/var_arr_typedef/pack.ads: New file.
* gdb.ada/var_arr_typedef/var_arr_typedef.adb: New file.
In Ada, index types of arrays can be enumeration types, and enumeration
types can be non-contiguous. In which case the address of elements is
not given by the value of the index, but by its position in the enumeration
type.
In other words, in this example:
type Color is (Blue, Red);
for Color use (Blue => 8, Red => 12, Green => 16);
type A is array (Color) of Integer;
type B is array (1 .. 3) of Integer;
Arrays of type A and B will have the same layout in memory, even if
the enumeration Color has a hole in its set of integer value.
Since recently support for such a feature was in ada-lang.c, where the
array was casted to a regular continuous index range. We were losing
the information of index type. And this was not quite working for
subranges in variable-length fields; their bounds are expressed using
the integer value of the bounds, not its position in the enumeration,
and there was some confusion all over ada-lang.c as to whether we had
the position or the integer value was used for indexes.
The idea behind this patch is to clean this up by keeping the real
representation of these array index types and bounds when representing
the value, and only use the position when accessing the elements or
computing the length. This first patch fixes the printing of such
an array.
To the best of my knowledge, this feature only exists in Ada so it
should only affect this language.
gdb/ChangeLog:
Jerome Guitton <guitton@adacore.com>:
* ada-lang.c (ada_value_ptr_subscript): Use enum position of
index to get element instead of enum value.
(ada_value_slice_from_ptr, ada_value_slice): Use enum position
of index to compute length, but enum values to compute bounds.
(ada_array_length): Use enum position of index instead of enum value.
(pos_atr): Move position computation to...
(ada_evaluate_subexp): Use enum values to compute bounds.
* gdbtypes.c (discrete_position): ...this new function.
* gdbtypes.h (discrete_position): New function declaration.
* valprint.c (val_print_array_elements): Call discrete_position
to handle array indexed by non-contiguous enumeration types.
gdb/testsuite/ChangeLog:
* gdb.ada/arr_enum_with_gap: New testcase.
This is the second part of enhancing the debugger to print the value
of arrays of records whose size is variable when only standard DWARF
info is available (no GNAT encoding). For instance:
subtype Small_Type is Integer range 0 .. 10;
type Record_Type (I : Small_Type := 0) is record
S : String (1 .. I);
end record;
type Array_Type is array (Integer range <>) of Record_Type;
A1 : Array_Type := (1 => (I => 0, S => <>),
2 => (I => 1, S => "A"),
3 => (I => 2, S => "AB"));
Currently, GDB prints the following output:
(gdb) p a1
$1 = (
The error happens while the ada-valprint module is trying to print
the value of an element of our array. Because of the fact that
the array's element (type Record_Type) has a variant size, the DWARF
info for our array provide the array's stride:
<1><749>: Abbrev Number: 10 (DW_TAG_array_type)
<74a> DW_AT_name : (indirect string, offset: 0xb6d): pck__T18s
<74e> DW_AT_byte_stride : 16
<74f> DW_AT_type : <0x6ea>
And because our array has a stride, ada-valprint treats it the same
way as packed arrays (see ada-valprint.c::ada_val_print_array):
if (TYPE_FIELD_BITSIZE (type, 0) > 0)
val_print_packed_array_elements (type, valaddr, offset_aligned,
0, stream, recurse,
original_value, options);
The first thing that we should notice in the call above is that
the "valaddr" buffer and the associated offset (OFFSET_ALIGNED)
is passed, but that the corresponding array's address is not.
This can be explained by looking inside val_print_packed_array_elements,
where we see that the function unpacks each element of our array from
the buffer alone (ada_value_primitive_packed_val), and then prints
the resulting artificial value instead:
v0 = ada_value_primitive_packed_val (NULL, valaddr + offset,
(i0 * bitsize) / HOST_CHAR_BIT,
(i0 * bitsize) % HOST_CHAR_BIT,
bitsize, elttype);
[...]
val_print (elttype, value_contents_for_printing (v0),
value_embedded_offset (v0), 0, stream,
recurse + 1, v0, &opts, current_language);
Of particular interest, here, is the fact that we call val_print
with a null address, which is OK, since we're providing a buffer
instead (value_contents_for_printing). Also, providing an address
might not always possible, since packing could place elements at
boundaries that are not byte-aligned.
Things go south when val_print tries to see if there is a pretty-printer
that could be applied. In particular, one of the first things that
the Python pretty-printer does is to create a value using our buffer,
and the given address, which in this case is null (see call to
value_from_contents_and_address in gdbpy_apply_val_pretty_printer).
value_from_contents_and_address, in turn immediately tries to resolve
the type, using the given address, which is null. But, because our
array element is a record containing an array whose bound is the value
of one of its elements (the "s" component), the debugging info for
the array's upper bound is a reference...
<3><71a>: Abbrev Number: 7 (DW_TAG_subrange_type)
<71b> DW_AT_type : <0x724>
<71f> DW_AT_upper_bound : <0x703>
... to component "i" of our record...
<2><703>: Abbrev Number: 5 (DW_TAG_member)
<704> DW_AT_name : i
<706> DW_AT_decl_file : 2
<707> DW_AT_decl_line : 6
<708> DW_AT_type : <0x6d1>
<70c> DW_AT_data_member_location: 0
... where that component is located at offset 0 of the start
of the record. dwarf2_evaluate_property correctly determines
the offset where to load the value of the bound from, but then
tries to read that value from inferior memory using the address
that was given, which is null. See case PROP_ADDR_OFFSET in
dwarf2_evaluate_property:
val = value_at (baton->offset_info.type,
pinfo->addr + baton->offset_info.offset);
This triggers a memory error, which then causes the printing to terminate.
Since there are going to be situations where providing an address
alone is not going to be sufficient (packed arrays where array elements
are not stored at byte boundaries), this patch fixes the issue by
enhancing the type resolution to take both address and data. This
follows the same principle as the val_print module, where both
address and buffer ("valaddr") can be passed as arguments. If the data
has already been fetched from inferior memory (or provided by the
debugging info in some form -- Eg a constant), then use that data
instead of reading it from inferior memory.
Note that this should also be a good step towards being able to handle
dynamic types whose value is stored outside of inferior memory
(Eg: in a register).
With this patch, GDB isn't able to print all of A1, but does perform
a little better:
(gdb) p a1
$1 = ((i => 0, s => , (i => 1, s => , (i => 2, s => )
There is another issue which is independent of this one, and will
therefore be patched separately.
gdb/ChangeLog:
* dwarf2loc.h (struct property_addr_info): Add "valaddr" field.
* dwarf2loc.c (dwarf2_evaluate_property): Add handling of
pinfo->valaddr.
* gdbtypes.h (resolve_dynamic_type): Add "valaddr" parameter.
* gdbtypes.c (resolve_dynamic_struct): Set pinfo.valaddr.
(resolve_dynamic_type_internal): Set pinfo.valaddr.
Add handling of addr_stack->valaddr.
(resolve_dynamic_type): Add "valaddr" parameter.
Set pinfo.valaddr field.
* ada-lang.c (ada_discrete_type_high_bound): Update call to
resolve_dynamic_type.
(ada_discrete_type_low_bound): Likewise.
* findvar.c (default_read_var_value): Likewise.
* value.c (value_from_contents_and_address): Likewise.
Consider the following (Ada) variable...
A1 : Array_Type := (1 => (I => 0, S => <>),
2 => (I => 1, S => "A"),
3 => (I => 2, S => "AB"));
... where Array_Type is an array of records whose size is variable:
subtype Small_Type is Integer range 0 .. 10;
type Record_Type (I : Small_Type := 0) is record
S : String (1 .. I);
end record;
type Array_Type is array (Integer range <>) of Record_Type;
Trying to print the value of this array currently results in the following
error:
(gdb) p a1
Cannot access memory at address 0x61c000
What happens in this case, is that the compiler describes our array
as an array with a specific stride (and bounds being static 1..3):
<1><749>: Abbrev Number: 10 (DW_TAG_array_type)
<74a> DW_AT_name : (indirect string, offset: 0xb6d): pck__T18s
<74e> DW_AT_byte_stride : 16
<74f> DW_AT_type : <0x6ea>
<2><757>: Abbrev Number: 11 (DW_TAG_subrange_type)
<758> DW_AT_type : <0x75e>
<75c> DW_AT_upper_bound : 3
This is because we cannot use, in this case, the size of the record
to determine that stride, since the size of the record depends on
its contents. So the compiler helps us by providing that stride.
The problems start when trying to resolve that type. Because the elements
contained in that array type are dynamic, the array itself is considered
dynamic, and thus we end up creating a resolved version of that array.
And during that resolution, we were not handling the case where the array
had a stride. See gdbtypes.c::resolve_dynamic_array...
return create_array_type (copy_type (type),
elt_type,
range_type);
As a result, we created an array whose stride was based on the size
of elt_type, which a record whose size isn't static and irrelevant
regardless.
This patch fixes is by calling create_array_type_with_stride instead.
As it happens, there is another issue for us to be able to print
the value of our array, but those are independent of this patch
and will be handled separately. For now, the patch allows us to
get rid of the first error, and the output is now:
(gdb) p a1
$1 = (
gdb/ChangeLog:
* gdbtypes.c (resolve_dynamic_array): Use
create_array_type_with_stride instead of create_array_type.
Currently, ada-lang.c:template_to_static_fixed_type (working on
structure types only) caches its result into the unused TYPE_TARGET_TYPE
field. This introduces inconsistencies when the input type is
specialized, for instance during type resolution: the cached static
fixed type is copied along with the original type, but it's no longer
adapted to the copy once the copy is modified:
template_to_static_fixed_type has to compute another static fixed type
for it.
This change first introduces a cache reset during type resolution for
structure types so that this inconsistency does not happen anymore. It
also makes template_to_static_fixed_type smarter with respect to types
that do not need static fixed copies so that less computations is done
in general.
This inconsistency was spotted thanks to code reading, not because of
any sort of failure and we did not manage to exhibit a failure yet, so
no testcase for this.
gdb/ChangeLog:
* ada-lang.c (template_to_static_fixed_type): Return input type
when it is already fixed. Cache the input type itself when not
creating a static fixed copy. Make it explicit that we never
molestate the input type.
* gdbtypes.c (resolve_dynamic_struct): Reset the
TYPE_TARGET_TYPE field for resolved copies.
gdb/ChangeLog:
2015-04-24 Pierre-Marie de Rodat <derodat@adacore.com>
* gdbtypes.c (print_gnat_stuff): Do not recurse on the
descriptive type when there is none.
This paramater is no longer useful after the previous commit, so remove
it as a cleanup.
gdb/ChangeLog:
* gdbtypes.c (is_dynamic_type_internal): Remove the unused
"top_level" parameter.
(resolve_dynamic_type_internal): Remove the unused "top_level"
parameter. Update call to is_dynamic_type_internal.
(is_dynamic_type): Update call to is_dynamic_type_internal.
(resolve_dynamic_range): Update call to
resolve_dynamic_type_internal.
(resolve_dynamic_union): Likewise.
(resolve_dynamic_struct): Likewise.
(resolve_dynamic_type): Likewise.
Even when referenced types are dynamic, the corresponding referencing
type should not be considered as dynamic: it's only a pointer. This
prevents reference type for values not in memory to be resolved.
gdb/ChangeLog:
* gdbtypes.c (is_dynamic_type_internal): Remove special handling
of TYPE_CODE_REF types so that they are not considered as
dynamic depending on the referenced type.
(resolve_dynamic_type_internal): Likewise.
gdb/testsuite/ChangeLog:
* gdb.ada/funcall_ref.exp: New file.
* gdb.ada/funcall_ref/foo.adb: New file.
struct dynamic_prop_list is declared as follow:
struct dynamic_prop_list
{
[...]
/* The dynamic property itself. */
struct dynamic_prop *prop;
[...]
};
In this case, the pointer indirection is unnecessary and costing us,
for each dynamic property, the memory needed to store one pointer.
This patch removes this pointer indirection, savin us a tiny bit of
memory, as well as reduces a bit the complexity by removing the need
to allocate memory for the property, as the allocation is now part
of the struct itself.
gdb/ChangeLog:
* gdbtypes.h (struct dynamic_prop_list) <prop>: Remove
pointer indirection.
* gdbtypes.c (get_dyn_prop): Adjust, following change above.
(add_dyn_prop, copy_dynamic_prop_list): Likewise.
Tested on x86_64-linux.
This patch introduces a linked list for dynamic attributes of a type.
This is a pre-work for the Fortran dynamic array support. The Fortran
dynamic array support will add more dynamic attributes to a type.
As only a few types will have such dynamic attributes set, a linked
list is more efficient in terms of memory consumption than adding
multiple attributes to main_type.
gdb/ChangeLog:
* gdbtypes.c (resolve_dynamic_type_internal): Adapt
data_location usage to linked list.
(resolve_dynamic_type_internal): Adapt data_location to
linked list.
(get_dyn_prop, add_dyn_prop, copy_dynamic_prop_list): New function.
(copy_type_recursive, copy_type): Add copy of linked list.
* gdbtypes.h (enum dynamic_prop_node_kind): New enum.
(struct dynamic_prop_list): New struct.
* dwarf2read.c (set_die_type): Set data_location data.
All these were caught by actually making TRY/CATCH use try/catch
behind the scenes, which then resulted in the build failing (on x86_64
Fedora 20) because there was code between the try and catch blocks.
gdb/ChangeLog:
2015-03-07 Pedro Alves <palves@redhat.com>
* breakpoint.c (save_breakpoints): Adjust to avoid code between
TRY and CATCH.
* gdbtypes.c (safe_parse_type): Remove empty line.
(types_deeply_equal):
* guile/scm-frame.c (gdbscm_frame_name):
* linux-thread-db.c (find_new_threads_once):
* python/py-breakpoint.c (bppy_get_commands):
* record-btrace.c (record_btrace_insert_breakpoint)
(record_btrace_remove_breakpoint, record_btrace_start_replaying)
(record_btrace_start_replaying): Adjust to avoid code between TRY
and CATCH.
This patch splits the TRY_CATCH macro into three, so that we go from
this:
~~~
volatile gdb_exception ex;
TRY_CATCH (ex, RETURN_MASK_ERROR)
{
}
if (ex.reason < 0)
{
}
~~~
to this:
~~~
TRY
{
}
CATCH (ex, RETURN_MASK_ERROR)
{
}
END_CATCH
~~~
Thus, we'll be getting rid of the local volatile exception object, and
declaring the caught exception in the catch block.
This allows reimplementing TRY/CATCH in terms of C++ exceptions when
building in C++ mode, while still allowing to build GDB in C mode
(using setjmp/longjmp), as a transition step.
TBC, after this patch, is it _not_ valid to have code between the TRY
and the CATCH blocks, like:
TRY
{
}
// some code here.
CATCH (ex, RETURN_MASK_ERROR)
{
}
END_CATCH
Just like it isn't valid to do that with C++'s native try/catch.
By switching to creating the exception object inside the CATCH block
scope, we can get rid of all the explicitly allocated volatile
exception objects all over the tree, and map the CATCH block more
directly to C++'s catch blocks.
The majority of the TRY_CATCH -> TRY+CATCH+END_CATCH conversion was
done with a script, rerun from scratch at every rebase, no manual
editing involved. After the mechanical conversion, a few places
needed manual intervention, to fix preexisting cases where we were
using the exception object outside of the TRY_CATCH block, and cases
where we were using "else" after a 'if (ex.reason) < 0)' [a CATCH
after this patch]. The result was folded into this patch so that GDB
still builds at each incremental step.
END_CATCH is necessary for two reasons:
First, because we name the exception object in the CATCH block, which
requires creating a scope, which in turn must be closed somewhere.
Declaring the exception variable in the initializer field of a for
block, like:
#define CATCH(EXCEPTION, mask) \
for (struct gdb_exception EXCEPTION; \
exceptions_state_mc_catch (&EXCEPTION, MASK); \
EXCEPTION = exception_none)
would avoid needing END_CATCH, but alas, in C mode, we build with C90,
which doesn't allow mixed declarations and code.
Second, because when TRY/CATCH are wired to real C++ try/catch, as
long as we need to handle cleanup chains, even if there's no CATCH
block that wants to catch the exception, we need for stop at every
frame in the unwind chain and run cleanups, then rethrow. That will
be done in END_CATCH.
After we require C++, we'll still need TRY/CATCH/END_CATCH until
cleanups are completely phased out -- TRY/CATCH in C++ mode will
save/restore the current cleanup chain, like in C mode, and END_CATCH
catches otherwise uncaugh exceptions, runs cleanups and rethrows, so
that C++ cleanups and exceptions can coexist.
IMO, this still makes the TRY/CATCH code look a bit more like a
newcomer would expect, so IMO worth it even if we weren't considering
C++.
gdb/ChangeLog.
2015-03-07 Pedro Alves <palves@redhat.com>
* common/common-exceptions.c (struct catcher) <exception>: No
longer a pointer to volatile exception. Now an exception value.
<mask>: Delete field.
(exceptions_state_mc_init): Remove all parameters. Adjust.
(exceptions_state_mc): No longer pop the catcher here.
(exceptions_state_mc_catch): New function.
(throw_exception): Adjust.
* common/common-exceptions.h (exceptions_state_mc_init): Remove
all parameters.
(exceptions_state_mc_catch): Declare.
(TRY_CATCH): Rename to ...
(TRY): ... this. Remove EXCEPTION and MASK parameters.
(CATCH, END_CATCH): New.
All callers adjusted.
gdb/gdbserver/ChangeLog:
2015-03-07 Pedro Alves <palves@redhat.com>
Adjust all callers of TRY_CATCH to use TRY/CATCH/END_CATCH
instead.
This commit introduces a new inline common function "startswith"
which takes two string arguments and returns nonzero if the first
string starts with the second. It also updates the 295 places
where this logic was written out longhand to use the new function.
gdb/ChangeLog:
* common/common-utils.h (startswith): New inline function.
All places where this logic was used updated to use the above.
This patch renames symbols that happen to have names which are
reserved keywords in C++.
Most of this was generated with Tromey's cxx-conversion.el script.
Some places where later hand massaged a bit, to fix formatting, etc.
And this was rebased several times meanwhile, along with re-running
the script, so re-running the script from scratch probably does not
result in the exact same output. I don't think that matters anyway.
gdb/
2015-02-27 Tom Tromey <tromey@redhat.com>
Pedro Alves <palves@redhat.com>
Rename symbols whose names are reserved C++ keywords throughout.
gdb/gdbserver/
2015-02-27 Tom Tromey <tromey@redhat.com>
Pedro Alves <palves@redhat.com>
Rename symbols whose names are reserved C++ keywords throughout.
Every type has to pay the price in memory usage for their presence.
The proper place for them is in the type_specific field which exists
for this purpose.
gdb/ChangeLog:
* dwarf2read.c (process_structure_scope): Update setting of
TYPE_VPTR_BASETYPE, TYPE_VPTR_FIELDNO.
* gdbtypes.c (internal_type_vptr_fieldno): New function.
(set_type_vptr_fieldno): New function.
(internal_type_vptr_basetype): New function.
(set_type_vptr_basetype): New function.
(get_vptr_fieldno): Update setting of TYPE_VPTR_FIELDNO,
TYPE_VPTR_BASETYPE.
(allocate_cplus_struct_type): Initialize vptr_fieldno.
(recursive_dump_type): Printing of vptr_fieldno, vptr_basetype ...
(print_cplus_stuff): ... moved here.
(copy_type_recursive): Don't copy TYPE_VPTR_BASETYPE.
* gdbtypes.h (struct main_type): Members vptr_fieldno, vptr_basetype
moved to ...
(struct cplus_struct_type): ... here. All uses updated.
(TYPE_VPTR_FIELDNO, TYPE_VPTR_BASETYPE): Rewrite.
(internal_type_vptr_fieldno, set_type_vptr_fieldno): Declare.
(internal_type_vptr_basetype, set_type_vptr_basetype): Declare.
* stabsread.c (read_tilde_fields): Update setting of
TYPE_VPTR_FIELDNO, TYPE_VPTR_BASETYPE.
gdb/testsuite/ChangeLog:
* gdb.base/maint.exp <maint print type argc>: Update expected output.
This patch moves TYPE_SELF_TYPE into new field type_specific.self_type
for MEMBERPTR,METHODPTR types, and into type_specific.func_stuff
for METHODs, and then updates everything to use that.
TYPE_CODE_METHOD could share some things with TYPE_CODE_FUNC
(e.g. TYPE_NO_RETURN) and it seemed simplest to keep them together.
Moving TYPE_SELF_TYPE into type_specific.func_stuff for TYPE_CODE_METHOD
is also nice because when we allocate space for function types we assume
they're TYPE_CODE_FUNCs. If TYPE_CODE_METHODs don't need or use that
space then that space would be wasted, and cleaning that up would involve
more invasive changes.
In order to catch errant uses I've added accessor functions
that do some checking.
One can no longer assign to TYPE_SELF_TYPE like this:
TYPE_SELF_TYPE (foo) = bar;
One instead has to do:
set_type_self_type (foo, bar);
But I've left reading of the type to the macro:
bar = TYPE_SELF_TYPE (foo);
In order to discourage bypassing the TYPE_SELF_TYPE macro
I've named the underlying function that implements it
internal_type_self_type.
While testing this I found the stabs reader leaving methods
as TYPE_CODE_FUNCs, hitting my newly added asserts.
Since the dwarf reader smashes functions to methods (via
smash_to_method) I've done a similar thing for stabs.
gdb/ChangeLog:
* cp-valprint.c (cp_find_class_member): Rename parameter domain_p
to self_p.
(cp_print_class_member): Rename local domain to self_type.
* dwarf2read.c (quirk_gcc_member_function_pointer): Rename local
domain_type to self_type.
(set_die_type) <need_gnat_info>: Handle
TYPE_CODE_METHODPTR, TYPE_CODE_MEMBERPTR, TYPE_CODE_METHOD.
* gdb-gdb.py (StructMainTypePrettyPrinter): Handle
TYPE_SPECIFIC_SELF_TYPE.
* gdbtypes.c (internal_type_self_type): New function.
(set_type_self_type): New function.
(smash_to_memberptr_type): Rename parameter domain to self_type.
Update setting of TYPE_SELF_TYPE.
(smash_to_methodptr_type): Update setting of TYPE_SELF_TYPE.
(smash_to_method_type): Rename parameter domain to self_type.
Update setting of TYPE_SELF_TYPE.
(check_stub_method): Call smash_to_method_type.
(recursive_dump_type): Handle TYPE_SPECIFIC_SELF_TYPE.
(copy_type_recursive): Ditto.
* gdbtypes.h (enum type_specific_kind): New value
TYPE_SPECIFIC_SELF_TYPE.
(struct main_type) <type_specific>: New member self_type.
(struct cplus_struct_type) <fn_field.type>: Update comment.
(TYPE_SELF_TYPE): Rewrite.
(internal_type_self_type, set_type_self_type): Declare.
* gnu-v3-abi.c (gnuv3_print_method_ptr): Rename local domain to
self_type.
(gnuv3_method_ptr_to_value): Rename local domain_type to self_type.
* m2-typeprint.c (m2_range): Replace TYPE_SELF_TYPE with
TYPE_TARGET_TYPE.
* stabsread.c (read_member_functions): Mark methods with
TYPE_CODE_METHOD, not TYPE_CODE_FUNC. Update setting of
TYPE_SELF_TYPE.
Consider the following declarations:
type Array_Type is array (Integer range <>) of Integer;
type Record_Type (N : Integer) is record
A : Array_Type (1 .. N);
end record;
R : Record_Type := Get (10);
It defines what Ada programers call a "discriminated record", where
"N" is a component of that record called a "discriminant", and where
"A" is a component defined as an array type whose upper bound is
equal to the value of the discriminant.
So far, we rely on a number of fairly complex GNAT-specific encodings
to handle this situation. This patch is to enhance GDB to be able to
print this record in the case where the compiler has been modified
to replace those encodings by pure DWARF constructs.
In particular, the debugging information generated for the record above
looks like the following. "R" is a record..
.uleb128 0x10 # (DIE (0x13e) DW_TAG_structure_type)
.long .LASF17 # DW_AT_name: "foo__record_type"
... whose is is of course dynamic (not our concern here)...
.uleb128 0xd # DW_AT_byte_size
.byte 0x97 # DW_OP_push_object_address
.byte 0x94 # DW_OP_deref_size
.byte 0x4
.byte 0x99 # DW_OP_call4
.long 0x19b
.byte 0x23 # DW_OP_plus_uconst
.uleb128 0x7
.byte 0x9 # DW_OP_const1s
.byte 0xfc
.byte 0x1a # DW_OP_and
.byte 0x1 # DW_AT_decl_file (foo.adb)
.byte 0x6 # DW_AT_decl_line
... and then has 2 members, fist "n" (our discriminant);
.uleb128 0x11 # (DIE (0x153) DW_TAG_member)
.ascii "n\0" # DW_AT_name
.byte 0x1 # DW_AT_decl_file (foo.adb)
.byte 0x6 # DW_AT_decl_line
.long 0x194 # DW_AT_type
.byte 0 # DW_AT_data_member_location
... and "A"...
.uleb128 0x11 # (DIE (0x181) DW_TAG_member)
.ascii "a\0" # DW_AT_name
.long 0x15d # DW_AT_type
.byte 0x4 # DW_AT_data_member_location
... which is an array ...
.uleb128 0x12 # (DIE (0x15d) DW_TAG_array_type)
.long .LASF18 # DW_AT_name: "foo__record_type__T4b"
.long 0x194 # DW_AT_type
... whose lower bound is implicitly 1, and the upper bound
a reference to DIE 0x153 = "N":
.uleb128 0x13 # (DIE (0x16a) DW_TAG_subrange_type)
.long 0x174 # DW_AT_type
.long 0x153 # DW_AT_upper_bound
This patch enhanced GDB to understand references to other DIEs
where the DIE's address is at an offset of its enclosing type.
The difficulty was that the address used to resolve the array's
type (R's address + 4 bytes) is different from the address used
as the base to compute N's address (an offset to R's address).
We're solving this issue by using a stack of addresses rather
than a single address when trying to resolve a type. Each address
in the stack corresponds to each containing level. For instance,
if resolving the field of a struct, the stack should contain
the address of the field at the top, and then the address of
the struct. That way, if the field makes a reference to an object
of the struct, we can retrieve the address of that struct, and
properly resolve the dynamic property references that struct.
gdb/ChangeLog:
* gdbtypes.h (struct dynamic_prop): New PROP_ADDR_OFFSET enum
kind.
* gdbtypes.c (resolve_dynamic_type_internal): Replace "addr"
parameter by "addr_stack" parameter.
(resolve_dynamic_range): Replace "addr" parameter by
"stack_addr" parameter. Update function documentation.
Update code accordingly.
(resolve_dynamic_array, resolve_dynamic_union)
(resolve_dynamic_struct, resolve_dynamic_type_internal): Likewise.
(resolve_dynamic_type): Update code, following the changes made
to resolve_dynamic_type_internal's interface.
* dwarf2loc.h (struct property_addr_info): New.
(dwarf2_evaluate_property): Replace "address" parameter
by "addr_stack" parameter. Adjust function documentation.
(struct dwarf2_offset_baton): New.
(struct dwarf2_property_baton): Update documentation of
field "referenced_type" to be more general. New field
"offset_info" in union data field.
* dwarf2loc.c (dwarf2_evaluate_property): Replace "address"
parameter by "addr_stack" parameter. Adjust code accordingly.
Add support for PROP_ADDR_OFFSET properties.
* dwarf2read.c (attr_to_dynamic_prop): Add support for
DW_AT_data_member_location attributes as well. Use case
statements instead of if/else condition.
gdb/testsuite/ChangeLog:
* gdb.ada/disc_arr_bound: New testcase.
Tested on x86_64-linux, no regression.
Consider the following code:
type Record_Type (N : Integer) is record
A : Array_Type (1 .. N);
end record;
[...]
R : Record_Type := Get (10);
Trying to print the bounds of the array R.A yielded:
(gdb) p r.a'last
$4 = cannot find reference address for offset property
A slightly different example, but from the same cause:
(gdb) ptype r
type = <ref> record
n: integer;
a: array (cannot find reference address for offset property
Looking at the debugging info, "A" is described as...
.uleb128 0x11 # (DIE (0x181) DW_TAG_member)
.ascii "a\0" # DW_AT_name
.long 0x15d # DW_AT_type
[...]
... which is an array...
.uleb128 0x12 # (DIE (0x15d) DW_TAG_array_type)
.long .LASF18 # DW_AT_name: "foo__record_type__T4b"
.long 0x194 # DW_AT_type
.long 0x174 # DW_AT_sibling
... whose bounds are described as:
.uleb128 0x13 # (DIE (0x16a) DW_TAG_subrange_type)
.long 0x174 # DW_AT_type
.long 0x153 # DW_AT_upper_bound
.byte 0 # end of children of DIE 0x15d
We can see above that the range has an implict lower value of
1, and an upper value which is a reference 0x153="n". All Good.
But looking at the array's subrange subtype, we see...
.uleb128 0x14 # (DIE (0x174) DW_TAG_subrange_type)
.long 0x153 # DW_AT_upper_bound
.long .LASF19 # DW_AT_name: "foo__record_type__T3b"
.long 0x18d # DW_AT_type
... another subrange type whose bounds are exactly described
the same way. So we have a subrange of a subrange, both with
one bound that's dynamic.
What happens in the case above is that GDB's resolution of "R.A"
yields a array whose index type has static bounds. However, the
subtype of the array's index type was left untouched, so, when
taking the subtype of the array's subrange type, we were left
with the unresolved subrange type, triggering the error above.
gdb/ChangeLog:
* gdbtypes.c (is_dynamic_type_internal) <TYPE_CODE_RANGE>: Return
nonzero if the type's subtype is dynamic.
(resolve_dynamic_range): Also resolve the range's subtype.
Tested on x86_64-linux, no regression.
gdb/ChangeLog:
* ada-lang.c (user_select_syms): Only fetch symtab if symbol is
objfile-owned.
(cache_symbol): Ignore symbols that are not objfile-owned.
* block.c (block_objfile): New function.
(block_gdbarch): New function.
* block.h (block_objfile): Declare.
(block_gdbarch): Declare.
* c-exp.y (classify_name): Remove call to
language_lookup_primitive_type. No longer necessary.
* gdbtypes.c (lookup_typename): Call lookup_symbol_in_language.
Remove call to language_lookup_primitive_type. No longer necessary.
* guile/scm-symbol.c (syscm_gdbarch_data_key): New static global.
(syscm_gdbarch_data): New struct.
(syscm_init_arch_symbols): New function.
(syscm_get_symbol_map): Renamed from syscm_objfile_symbol_map.
All callers updated. Handle symbols owned by arches.
(gdbscm_symbol_symtab): Handle symbols owned by arches.
(gdbscm_initialize_symbols): Initialize syscm_gdbarch_data_key.
* language.c (language_lookup_primitive_type_1): New function.
(language_lookup_primitive_type): Call it.
(language_alloc_type_symbol): New function.
(language_init_primitive_type_symbols): New function.
(language_lookup_primitive_type_as_symbol): New function.
* language.h (struct language_arch_info) <primitive_type_symbols>:
New member.
(language_lookup_primitive_type): Add function comment.
(language_lookup_primitive_type_as_symbol): Declare.
* printcmd.c (address_info): Handle arch-owned symbols.
* python/py-symbol.c (sympy_get_symtab): Ditto.
(set_symbol): Ditto.
(sympy_dealloc): Ditto.
* symmisc.c (print_symbol): Ditto.
* symtab.c (fixup_symbol_section): Ditto.
(lookup_symbol_aux): Initialize block_found.
(basic_lookup_symbol_nonlocal): Try looking up the symbol as a
primitive type.
(initialize_objfile_symbol_1): New function.
(initialize_objfile_symbol): Call it.
(allocate_symbol): Call it.
(allocate_template_symbol): Call it.
(symbol_objfile): Assert symbol is objfile-owned.
(symbol_arch, symbol_symtab, symbol_set_symtab): Ditto.
* symtab.h (struct symbol) <owner>: Replaces member "symtab".
(struct symbol) <is_objfile_owned>: New member.
(SYMBOL_OBJFILE_OWNED): New macro.
* cp-namespace.c (cp_lookup_bare_symbol): New arg langdef.
All callers updated. Try to find the symbol as a primitive type.
(lookup_namespace_scope): New arg langdef. All callers updated.
Call cp_lookup_bare_symbol directly for simple bare symbols.
https://sourceware.org/bugzilla/show_bug.cgi?id=17642
Regression since:
commit 012370f681
Author: Tom Tromey <tromey@redhat.com>
Date: Thu May 8 11:26:44 2014 -0600
handle VLA in a struct or union
Bugreport:
Regression with gdb scripts for Linux kernel
https://sourceware.org/ml/gdb/2014-08/msg00127.html
That big change after "else" is just reindentation.
gdb/ChangeLog
2014-12-13 Jan Kratochvil <jan.kratochvil@redhat.com>
PR symtab/17642
* gdbtypes.c (resolve_dynamic_type_internal): Apply check_typedef to
TYPE if not TYPE_CODE_TYPEDEF.
gdb/testsuite/ChangeLog
2014-12-13 Jan Kratochvil <jan.kratochvil@redhat.com>
PR symtab/17642
* gdb.base/vla-stub-define.c: New file.
* gdb.base/vla-stub.c: New file.
* gdb.base/vla-stub.exp: New file.
There's seemingly no function to get the unqualified variant of a
type, so this patch adds one. This new function will be used in the
final patch.
gdb/ChangeLog
2014-12-12 Tom Tromey <tromey@redhat.com>
* gdbtypes.h (make_unqualified_type): Declare.
* gdbtypes.c (make_unqualified_type): New function.
gdb/ChangeLog:
* eval.c: Include gdbthread.h.
(evaluate_subexp): Enable thread stack temporaries before
evaluating a complete expression and clean them up after the
evaluation is complete.
* gdbthread.h: Include common/vec.h.
(value_ptr): New typedef.
(VEC (value_ptr)): New vector type.
(value_vec): New typedef.
(struct thread_info): Add new fields stack_temporaries_enabled
and stack_temporaries.
(enable_thread_stack_temporaries)
(thread_stack_temporaries_enabled_p, push_thread_stack_temporary)
(get_last_thread_stack_temporary)
(value_in_thread_stack_temporaries): Declare.
* gdbtypes.c (class_or_union_p): New function.
* gdbtypes.h (class_or_union_p): Declare.
* infcall.c (call_function_by_hand): Store return values of class
type as temporaries on stack.
* thread.c (enable_thread_stack_temporaries): New function.
(thread_stack_temporaries_enabled_p, push_thread_stack_temporary)
(get_last_thread_stack_temporary): Likewise.
(value_in_thread_stack_temporaries): Likewise.
* value.c (value_force_lval): New function.
* value.h (value_force_lval): Declare.
gdb/testsuite/ChangeLog:
* gdb.cp/chained-calls.cc: New file.
* gdb.cp/chained-calls.exp: New file.
* gdb.cp/smartp.exp: Remove KFAIL for "p c2->inta".
gdb/ChangeLog:
* gdbtypes.c (print_args): Renamed from print_arg_types. Print arg
number and name if present. All callers updated.
(dump_fn_fieldlists): Fix indentation of args.
Consider the following variable declaration:
type Array_Type is array (Integer range <>) of Integer;
Var: Array_Type (0 .. -1);
"ptype var" prints the wrong upper bound for that array:
(gdb) ptype var
type = array (0 .. 4294967295) of integer
The debugging info for the type of variable "Var" is as follow:
<2><cf>: Abbrev Number: 13 (DW_TAG_structure_type)
<d0> DW_AT_name : foo__var___PAD
<3><db>: Abbrev Number: 14 (DW_TAG_member)
<dc> DW_AT_name : F
<e0> DW_AT_type : <0xa5>
This is just an artifact from code generation, which is just
a wrapper that we should ignore. The real type is the type of
field "F" in that PAD type, which is described as:
<2><a5>: Abbrev Number: 10 (DW_TAG_array_type)
<a6> DW_AT_name : foo__TvarS
<3><b6>: Abbrev Number: 11 (DW_TAG_subrange_type)
<b7> DW_AT_type : <0xc1>
<bb> DW_AT_lower_bound : 0
<bc> DW_AT_upper_bound : 0xffffffff
Trouble occurs because DW_AT_upper_bound is encoded using
a DW_FORM_data4, which is ambiguous regarding signedness.
In that case, dwarf2read.c::dwarf2_get_attr_constant_value
reads the value as unsigned, which is not what we want
in this case.
As it happens, we already have code dealing with this situation
in dwarf2read.c::read_subrange_type which checks whether
the subrange's type is signed or not, and if it is, fixes
the bound's value by sign-extending it:
if (high.kind == PROP_CONST
&& !TYPE_UNSIGNED (base_type) && (high.data.const_val & negative_mask))
high.data.const_val |= negative_mask;
Unfortunately, what happens in our case is that the base type
of the array's subrange type is marked as being unsigned, and
so we never get to apply the sign extension. Following the DWARF
trail, the range's base type is described as another subrange type...
<2><c1>: Abbrev Number: 12 (DW_TAG_subrange_type)
<c7> DW_AT_name : foo__TTvarSP1___XDLU_0__1m
<cb> DW_AT_type : <0x2d>
... whose base type is, (finally), a basic type (signed):
<1><2d>: Abbrev Number: 2 (DW_TAG_base_type)
<2e> DW_AT_byte_size : 4
<2f> DW_AT_encoding : 5 (signed)
<30> DW_AT_name : integer
The reason why GDB thinks that foo__TTvarSP1___XDLU_0__1m
(the base type of the array's range type) is an unsigned type
is found in gdbtypes.c::create_range_type. We consider that
a range type is unsigned iff its lower bound is >= 0:
if (low_bound->kind == PROP_CONST && low_bound->data.const_val >= 0)
TYPE_UNSIGNED (result_type) = 1;
That is normally sufficient, as one would expect the upper bound to
always be greater or equal to the lower bound. But Ada actually
allows the declaration of empty range types where the upper bound
is less than the lower bound. In this case, the upper bound is
negative, so we should not be marking the type as unsigned.
This patch fixes the issue by simply checking the upper bound as well
as the lower bound, and clears the range type's unsigned flag when
it is found to be constant and negative.
gdb/ChangeLog:
* gdbtypes.c (create_range_type): Unset RESULT_TYPE's
flag_unsigned if HIGH_BOUND is constant and negative.
gdb/testsuite/ChangeLog:
* gdb.ada/n_arr_bound: New testcase.
Tested on x86_64-linux.
gdb/ChangeLog:
* gdbtypes.h (struct main_type): Add field "data_location".
(TYPE_DATA_LOCATION, TYPE_DATA_LOCATION_BATON)
(TYPE_DATA_LOCATION_ADDR, TYPE_DATA_LOCATION_KIND): New macros.
* gdbtypes.c (is_dynamic_type): Return 1 if the type has
a dynamic data location.
(resolve_dynamic_type): Add DW_AT_data_location handling.
(copy_recursive, copy_type): Copy the data_location information
when present.
* dwarf2read.c (set_die_type): Add DW_AT_data_location handling.
* value.c (value_from_contents_and_address): Add
DW_AT_data_location handling.
In Ada, variable-sized field can be located at any position of
a structure. Consider for instance the following declarations:
Dyn_Size : Integer := 1;
type Table is array (Positive range <>) of Integer;
type Inner is record
T1 : Table (1 .. Dyn_Size) := (others => 1);
T2 : Table (1 .. Dyn_Size) := (others => 2);
end record;
type Inner_Array is array (1 .. 2) of Inner;
type Outer is
record
I0 : Integer := 0;
A1 : Inner_Array;
Marker : Integer := 16#01020304#;
end record;
Rt : Outer;
What this does is declare a variable "Rt" of type Outer, which
contains 3 fields where the second (A1) is of type Inner_Array.
type Inner_Array is an array with 2 elements of type Inner.
Because type Inner contains two arrays whose upper bound depend
on a variable, the size of the array, and therefore the size of
type Inner is dynamic, thus making field A1 a dynamically-size
field.
When trying to print the value of Rt, we hit the following limitation:
(gdb) print rt
Attempt to resolve a variably-sized type which appears in the interior of
a structure type
The limitation was somewhat making sense in C, but needs to be lifted
for Ada. This patch mostly lifts that limitation. As a result of this
patch, the type length computation had to be reworked a little bit.
gdb/ChangeLog:
* gdbtypes.c (resolve_dynamic_struct): Do not generate an error
if detecting a variable-sized field that is not the last field.
Fix struct type length computation.
gdb/testsuite/ChangeLog:
* gdb.base/vla-datatypes.c (vla_factory): Add new variable
inner_vla_struct_object_size.
* gdb.base/vla-datatypes.exp: Adjust last test, and mark it
as xfail.
This fixes PR 17106, a regression in printing.
The bug is that resolve_dynamic_type follows struct members and
references, but doesn't consider the possibility of infinite
recursion.
This patch fixes the problem by limiting reference following to the
topmost layer of calls -- that is, reference-typed struct members are
never considered as being VLAs.
Built and regtested on x86-64 Fedora 20.
New test case included.
2014-07-14 Tom Tromey <tromey@redhat.com>
PR exp/17106:
* gdbtypes.c (is_dynamic_type_internal): New function, from
is_dynamic_type.
(is_dynamic_type): Rewrite.
(resolve_dynamic_union): Use resolve_dynamic_type_internal.
(resolve_dynamic_struct): Likewise.
(resolve_dynamic_type_internal): New function, from
resolve_dynamic_type.
(resolve_dynamic_type): Rewrite.
2014-07-14 Tom Tromey <tromey@redhat.com>
* gdb.cp/vla-cxx.cc: New file.
* gdb.cp/vla-cxx.exp: New file.
It is valid in GNU C to have a VLA in a struct or union type, but gdb
did not handle this.
This patch adds support for these cases in the obvious way.
Built and regtested on x86-64 Fedora 20.
New tests included.
2014-06-04 Tom Tromey <tromey@redhat.com>
* ada-lang.c (ada_template_to_fixed_record_type_1): Use
value_from_contents_and_address_unresolved.
(ada_template_to_fixed_record_type_1): Likewise.
(ada_which_variant_applies): Likewise.
* value.h (value_from_contents_and_address_unresolved): Declare.
* value.c (value_from_contents_and_address_unresolved): New
function.
* gdbtypes.c (is_dynamic_type, resolve_dynamic_type)
<TYPE_CODE_STRUCT, TYPE_CODE_UNION>: New cases.
(resolve_dynamic_struct, resolve_dynamic_union): New functions.
2014-06-04 Tom Tromey <tromey@redhat.com>
* gdb.base/vla-datatypes.exp: Add tests for VLA-in-structure and
VLA-in-union.
* gdb.base/vla-datatypes.c (vla_factory): Add vla_struct,
inner_vla_struct, vla_union types. Initialize objects of those
types and compute their sizes.
I noticed that gdbtypes.c:is_dynamic_type has some unneeded "break"s.
This patch cleans up the function a bit, removing those and removing
the switch's default case so that the end of the function is a bit
clearer.
2014-06-04 Tom Tromey <tromey@redhat.com>
* gdbtypes.c (is_dynamic_type): Remove unneeded "break"s.
* defs.h (enum lval_type): New enumerator "lval_xcallable".
* extension-priv.h (struct extension_language_ops): Add the
xmethod interface.
* extension.c (new_xmethod_worker, clone_xmethod_worker,
get_matching_xmethod_workers, get_xmethod_argtypes,
invoke_xmethod, free_xmethod_worker,
free_xmethod_worker_vec): New functions.
* extension.h: #include "common/vec.h".
New function declarations.
(struct xmethod_worker): New struct.
(VEC (xmethod_worker_ptr)): New vector type.
(xmethod_worker_ptr): New typedef.
(xmethod_worker_vec): Likewise.
* gdbtypes.c (gdbtypes_post_init): Initialize "xmethod" field of
builtin_type.
* gdbtypes.h (enum type_code): New enumerator TYPE_CODE_XMETHOD.
(struct builtin_type): New field "xmethod".
* valarith.c (value_ptradd): Assert that the value argument is not
lval_xcallable.
* valops.c (value_must_coerce_to_target): Return 0 for
lval_xcallable values.
* value.c (struct value): New field XM_WORKER in the field
LOCATION.
(value_address, value_raw_address): Return 0 for lval_xcallable
values.
(set_value_address): Assert that the value is not an
lval_xcallable.
(value_free): Free the associated xmethod worker when freeing
lval_xcallable values.
(set_value_component_location): Assert that the WHOLE value is not
lval_xcallable.
(value_of_xmethod, call_xmethod): New functions.
* value.h: Declare "struct xmethod_worker".
Declare new functions value_of_xmethod, call_xmethod.
I'm checking this in as obvious.
I was looking at instances of "alloc.*sizeof" and noticed a couple
where the types in question are incorrect.
In gdbtypes, the code allocates sizeof(int) to represent a struct rank.
In mi-cmds, the code uses "struct mi_cmd **" -- one "*" too many.
In both cases the problems are latent because in practice the sizes
are the same as the sizes of the correct types. Still, it's better to
be correct.
I think gdb would be improved by a wholesale change from explicit
sizeofs to using the libiberty.h allocation macros. In most cases
they are both shorter and have better type safety. However, the
resulting patch is rather large.
Built and regtested on x86-64 Fedora 20.
2014-05-19 Tom Tromey <tromey@redhat.com>
* gdbtypes.c (rank_function): Use XNEWVEC.
* mi/mi-cmds.c (build_table): Use XCNEWVEC.
This change breaks down the resolve_dynamic_bounds function which
works only on arrays and its index range types into two functions,
one that resolves range types, and one that resolves arrays (using
the new routine to resolve the array's index range type). The
is_dynamic_type and resolve_dynamic_type function are then re-organized
to handle range types as well.
One small change worth mentioning is the fact that, now that range
types are resolved on their own (rather than in the limited context
of array index types), the resolved range types are created from
a copy of the dynamic range type, rather than from scratch (first
parameter of create_range_type). This allows us to preserve as many
original properties in the resolved type as possible (Eg. the type's
name).
This is preparation work that will help better support dynamic range
types for languages that allow the declaration of such types (Eg. Ada).
gdb/ChangeLog:
* dwarf2read.c (is_dynamic_type): Return true for dynamic
range types. Adjust the array handling implementation to
take advantage of this change.
(resolve_dynamic_range): New function, mostly extracted from
resolve_dynamic_bounds.
(resolve_dynamic_array): New function, mostly extracted from
resolve_dynamic_bounds.
(resolve_dynamic_bounds): Delete.
(resolve_dynamic_type): Reimplement. Add handling of
TYPE_CODE_RANGE types.
