There are cases where the result of the expression evaluation is
expected to be in a form of a value and not location description.
One place that has this requirement is dwarf_entry_parameter_to_value
function, but more are expected in the future. Until now, this
requirement was fulfilled by extending the evaluated expression with
a DW_OP_stack_value operation at the end.
New implementation, introduces a new evaluation argument instead.
* dwarf2/expr.c (dwarf_expr_context::fetch_result): Add as_lval
argument.
(dwarf_expr_context::eval_exp): Add as_lval argument.
* dwarf2/expr.h (struct dwarf_expr_context): Add as_lval
argument to fetch_result and eval_exp methods.
* dwarf2/frame.c (execute_stack_op): Add as_lval argument.
* dwarf2/loc.c (dwarf_entry_parameter_to_value): Remove
DWARF expression extension.
(dwarf2_evaluate_loc_desc_full): Add as_lval argument support.
(dwarf2_evaluate_loc_desc): Add as_lval argument support.
(dwarf2_locexpr_baton_eval): Add as_lval argument support.
The patch is addressing the issue of class users writing and reading
the internal data of the dwarf_expr_context class.
At this point, all conditions are met for the DWARF evaluator to return
an evaluation result in a form of a single struct value object.
gdb/ChangeLog:
* dwarf2/expr.c (pieced_value_funcs): Chenge to static
function.
(allocate_piece_closure): Change to static function.
(dwarf_expr_context::fetch_result): New function.
* dwarf2/expr.h (struct piece_closure): Remove declaration.
(struct dwarf_expr_context): fetch_result new declaration.
fetch, fetch_address and fetch_in_stack_memory members move
to private.
(allocate_piece_closure): Remove.
* dwarf2/frame.c (execute_stack_op): Change to use
fetch_result.
* dwarf2/loc.c (dwarf2_evaluate_loc_desc_full): Change to use
fetch_result.
(dwarf2_locexpr_baton_eval): Change to use fetch_result.
* dwarf2/loc.h (invalid_synthetic_pointer): Expose function.
Following 5 patches series is trying to clean up the interface of the
DWARF expression evaluator class (dwarf_expr_context).
After merging all expression evaluators into one class, the next
logical step is to make a clean user interface for that class. To do
that, we first need to address the issue of class users writing and
reading the internal data of the class directly.
Fixing the case of writing is simple, it makes sense for an evaluator
instance to be per architecture basis. Currently, the best separation
seems to be per object file, so having that data (dwarf2_per_objfile)
as a constructor argument makes sense. It also makes sense to get the
address size from that object file, but unfortunately that interface
does not exist at the moment.
Luckily, address size information is already available to the users
through other means. As a result, the address size also needs to be a
class constructor argument, at least until a better interface for
acquiring that information from an object file is implemented.
The rest of the user written data comes down to a context of an
evaluated expression (compilation unit context, frame context and
passed in buffer context) and a source type information that a result
of evaluating expression is representing. So, it makes sense for all of
these to be arguments of an evaluation method.
To address the problem of reading the dwarf_expr_context class
internal data, we first need to understand why it is implemented that
way?
This is actualy a question of which existing class can be used to
represent both values and a location descriptions and why it is not
used currently?
The answer is in a struct value class/structure, but the problem is
that before the evaluators were merged, only one evaluator had an
infrastructure to resolve composite and implicit pointer location
descriptions.
After the merge, we are now able to use the struct value to represent
any result of the expression evaluation. It also makes sense to move
all infrastructure for those location descriptions to the expr.c file
considering that that is the only place using that infrastructure.
What we are left with in the end is a clean public interface of the
dwarf_expr_context class containing:
- constructor,
- destructor,
- push_address method and
- eval_exp method.
The idea with this particular patch is to move piece_closure structure
and the interface that handles it (lval_funcs) to expr.c file.
While implicit pointer location descriptions are still not useful in
the CFI context (of the AMD's DWARF standard extensions), the composite
location descriptions are certainly necessary to describe a results of
specific compiler optimizations.
Considering that a piece_closure structure is used to represent both,
there was no benefit in splitting them.
gdb/ChangeLog:
* dwarf2/expr.c (struct piece_closure): Add from loc.c.
(allocate_piece_closure): Add from loc.c.
(bits_to_bytes): Add from loc.c.
(rw_pieced_value): Add from loc.c.
(read_pieced_value): Add from loc.c.
(write_pieced_value): Add from loc.c.
(check_pieced_synthetic_pointer): Add from loc.c.
(indirect_pieced_value): Add from loc.c.
(coerce_pieced_ref): Add from loc.c.
(copy_pieced_value_closure): Add from loc.c.
(free_pieced_value_closure): Add from loc.c.
(sect_variable_value): Add from loc.c.
* dwarf2/loc.c (sect_variable_value): Move to expr.c.
(struct piece_closure): Move to expr.c.
(allocate_piece_closure): Move to expr.c.
(bits_to_bytes): Move to expr.c.
(rw_pieced_value): Move to expr.c.
(read_pieced_value): Move to expr.c.
(write_pieced_value): Move to expr.c.
(check_pieced_synthetic_pointer): Move to expr.c.
(indirect_pieced_value): Move to expr.c.
(coerce_pieced_ref): Move to expr.c.
(copy_pieced_value_closure): Move to expr.c.
(free_pieced_value_closure): Move to expr.c.
Following the idea of merging the evaluators, the
push_dwarf_reg_entry_value method can be moved from
dwarf_expr_executor and dwarf_evaluate_loc_desc classes
to their base class dwarf_expr_context.
gdb/ChangeLog:
* dwarf2/expr.c
(dwarf_expr_context::push_dwarf_reg_entry_value): Move from
dwarf_evaluate_loc_desc.
* dwarf2/frame.c
(dwarf_expr_executor::push_dwarf_reg_entry_value): Remove
method.
* dwarf2/loc.c (dwarf_expr_reg_to_entry_parameter): Expose
function.
(dwarf_evaluate_loc_desc::push_dwarf_reg_entry_value): Move to
dwarf_expr_context.
* dwarf2/loc.h (dwarf_expr_reg_to_entry_parameter): Expose
function.
This patch moves the compilation unit context information and support
from dwarf_expr_executor and dwarf_evaluate_loc_desc to
dwarf_expr_context evaluator. The idea is to report an error when a
given operation requires a compilation unit information to be resolved,
which is not available.
With this change, it also makes sense to always acquire ref_addr_size
information from the compilation unit context, considering that all
DWARF operations that refer to that information require a compilation
unit context to be present during their evaluation.
gdb/ChangeLog:
* dwarf2/expr.c (ensure_have_per_cu): New function.
(dwarf_expr_context::dwarf_expr_context): Add compilation unit
context information.
(dwarf_expr_context::get_base_type): Move from
dwarf_evaluate_loc_desc.
(dwarf_expr_context::get_addr_index): Remove method.
(dwarf_expr_context::dwarf_variable_value): Remove method.
(dwarf_expr_context::execute_stack_op): Call compilation unit
context info check. Inline get_addr_index and
dwarf_variable_value methods.
* dwarf2/expr.h (struct dwarf_expr_context): Add compilation
context info.
(dwarf_expr_context::get_addr_index): Remove method.
(dwarf_expr_context::dwarf_variable_value): Remove method.
(dwarf_expr_context::ref_addr_size): Remove member.
* dwarf2/frame.c (dwarf_expr_executor::get_addr_index): Remove
method.
(dwarf_expr_executor::dwarf_variable_value): Remove method.
* dwarf2/loc.c (sect_variable_value): Expose function.
(dwarf_evaluate_loc_desc::get_addr_index): Remove method.
(dwarf_evaluate_loc_desc::dwarf_variable_value): Remove method.
(class dwarf_evaluate_loc_desc): Move compilation unit context
information to dwarf_expr_context class.
* dwarf2/loc.h (sect_variable_value): Expose function.
This is unused (and was event when it was introduced). Remove it.
gdb/ChangeLog:
* dwarf2/loc.h (struct call_site_stuff): Remove.
Change-Id: Iaa82cb7cfd9768998553b4c9211aca7529eb402f
This changes the GDB compile code to use std::vector<bool> when
computing which registers are used. This is a bit more idiomatic, but
the main benefit is that it also adds some checking when the libstd++
debug mode is enabled.
2021-01-23 Tom Tromey <tom@tromey.com>
* symtab.h (struct symbol_computed_ops) <generate_c_location>:
Change type of "registers_used".
* dwarf2/loc.h (dwarf2_compile_property_to_c): Update.
* dwarf2/loc.c (dwarf2_compile_property_to_c)
(locexpr_generate_c_location, loclist_generate_c_location): Change
type of "registers_used".
* compile/compile.h (compile_dwarf_expr_to_c)
(compile_dwarf_bounds_to_c): Update.
* compile/compile-loc2c.c (pushf_register_address)
(pushf_register, do_compile_dwarf_expr_to_c)
(compile_dwarf_expr_to_c, compile_dwarf_bounds_to_c): Change type
of "registers_used".
* compile/compile-c.h (generate_c_for_variable_locations):
Update.
* compile/compile-c-symbols.c (generate_vla_size)
(generate_c_for_for_one_variable): Change type of
"registers_used".
(generate_c_for_variable_locations): Return std::vector.
* compile/compile-c-support.c (generate_register_struct): Change
type of "registers_used".
(compute): Update.
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.
Since dwarf2_per_cu_data objects are going to become
objfile-independent, the backlink from dwarf2_per_cu_data to one
particular objfile must be removed. Instead, users of
dwarf2_per_cu_data that need an objfile must know from somewhere else in
the context of which objfile they are using this CU.
This also helps remove a dwarf2_per_cu_data::dwarf2_per_objfile
reference (from where the objfile was obtained).
Note that the dwarf2_per_cu_data::objfile method has a special case to
make sure to return the main objfile, if the objfile associated to the
dwarf2_per_cu_data is a separate debug objfile. I don't really know if
this is necessary: I ignored that, and didn't see any regression when
testing with the various Dejagnu boards with separate debug info, so I
presume it wasn't needed. If it turns out this was needed, then we can
have a helper method on the objfile type for that.
gdb/ChangeLog:
* dwarf2/read.h (struct dwarf2_per_cu_data) <objfile>: Remove.
* dwarf2/read.c (dwarf2_compute_name): Pass per_objfile down.
(read_call_site_scope): Assign per_objfile.
(dwarf2_per_cu_data::objfile): Remove.
* gdbtypes.h (struct call_site) <per_objfile>: New member.
* dwarf2/loc.h (dwarf2_evaluate_loc_desc): Add
dwarf2_per_objfile parameter.
* dwarf2/loc.c (dwarf2_evaluate_loc_desc_full): Add
dwarf2_per_objfile parameter.
(dwarf_expr_reg_to_entry_parameter): Add output
dwarf2_per_objfile parameter.
(locexpr_get_frame_base): Update.
(class dwarf_evaluate_loc_desc) <get_tls_address>: Update.
<push_dwarf_reg_entry_value>: Update.
<call_site_to_target_addr>: Update.
(dwarf_entry_parameter_to_value): Add dwarf2_per_objfile
parameter.
(value_of_dwarf_reg_entry): Update.
(rw_pieced_value): Update.
(indirect_synthetic_pointer): Update.
(dwarf2_evaluate_property): Update.
(dwarf2_loc_desc_get_symbol_read_needs): Add dwarf2_per_objfile
parameter.
(locexpr_read_variable): Update.
(locexpr_get_symbol_read_needs): Update.
(loclist_read_variable): Update.
Change-Id: Idb40d1a94995af305054d463967bb6ce11a08f25
Various DWARF callbacks expect to be able to fetch the objfile and / or
dwarf2_per_objfile from the DWARF CU object. However, this won't be
possible once sharing is implemented.
Because these objects are related to full symbols (e.g., they are used
to implement location expressions), they can simply store the
dwarf2_per_objfile they need.
This patch adds a per_objfile member to the various "baton" structures
and arranges to set this value when constructing the baton.
gdb/ChangeLog:
YYYY-MM-DD Tom Tromey <tom@tromey.com>
YYYY-MM-DD Simon Marchi <simon.marchi@efficios.com>
* dwarf2/loc.c (struct piece_closure) <per_objfile>: New member.
(allocate_piece_closure): Set "per_objfile" member.
(dwarf2_find_location_expression, dwarf2_locexpr_baton_eval)
(locexpr_describe_location, loclist_describe_location): Use new
member.
* dwarf2/read.c (read_call_site_scope)
(mark_common_block_symbol_computed, attr_to_dynamic_prop)
(dwarf2_const_value_attr, dwarf2_fetch_die_loc_sect_off)
(fill_in_loclist_baton, dwarf2_symbol_mark_computed,
handle_data_member_location): Set per_objfile member.
* dwarf2/loc.h (struct dwarf2_locexpr_baton) <per_objfile>: New
member.
(struct dwarf2_loclist_baton) <per_objfile>: New member.
Change-Id: If3aaa6a0f544be86710157c3adb68fde24d80037
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.
Some DWARF expressions must be evaluated by first pushing the object
address onto the evaluation stack. This patch adds this ability.
This functionality is not used yet, but it will be used in a later
patch. This is split out for easier review and also because it
improved the patch series ordering.
gdb/ChangeLog
2020-04-24 Tom Tromey <tromey@adacore.com>
* dwarf2/loc.c (dwarf2_locexpr_baton_eval): Add
"push_initial_value" parameter.
(dwarf2_evaluate_property): Likewise.
* dwarf2/loc.h (dwarf2_evaluate_property): Update.
dwarf2_evaluate_property should not modify its "addr_stack"
parameter's contents. This patch makes this part of the API, by
marking it const.
gdb/ChangeLog
2020-03-20 Tom Tromey <tromey@adacore.com>
* dwarf2/loc.h (dwarf2_evaluate_property): Make "addr_stack"
const.
* dwarf2/loc.c (dwarf2_evaluate_property): Make "addr_stack"
const.
All these functions have their implementations in dwarf2/read.c, so move
their declarations to dwarf2/read.h. Move the doc to the header, at the
same time.
gdb/ChangeLog:
* dwarf2/loc.h (dwarf2_fetch_die_loc_sect_off,
dwarf2_fetch_die_loc_cu_off, dwarf2_fetch_constant_bytes,
dwarf2_fetch_die_type_sect_off): Move to...
* dwarf2/read.h (dwarf2_fetch_die_loc_sect_off,
dwarf2_fetch_die_loc_cu_off, dwarf2_fetch_constant_bytes,
dwarf2_fetch_die_type_sect_off): ... here.
* dwarf2/read.c (dwarf2_fetch_die_loc_sect_off,
dwarf2_fetch_die_loc_cu_off, dwarf2_fetch_constant_bytes,
dwarf2_fetch_die_type_sect_off): Move doc to header file.
The implementation is in dwarf2/read.c, so the declaration belongs in
dwarf2/read.h. Also, move the documentation there.
gdb/ChangeLog:
* dwarf2/loc.h (dwarf2_read_addr_index): Move...
* dwarf2/read.h (dwarf2_read_addr_index): ... here.
* dwarf2/read.c (dwarf2_read_addr_index): Move doc to header.
Since its implementation is in dwarf2/read.c, its declaration belongs in
dwarf2/read.h. Move the documentation to the .h at the same time.
gdb/ChangeLog:
* loc.h (dwarf2_get_die_type): Move to...
* read.h (dwarf2_get_die_type): ... here.
* read.c (dwarf2_get_die_type): Move doc to header.
I noticed that dwarf2_compile_expr_to_ax can be static. Nothing
outside of loc.c calls it.
gdb/ChangeLog
2020-02-22 Tom Tromey <tom@tromey.com>
* dwarf2/loc.h (dwarf2_compile_expr_to_ax): Don't declare.
* dwarf2/loc.c (dwarf2_compile_expr_to_ax): Now static.
call_site_find_chain returns a pointer that the caller must
deallocate. It seemed better here to return a unique_xmalloc_ptr
instead.
gdb/ChangeLog
2020-02-14 Tom Tromey <tromey@adacore.com>
* dwarf2/frame-tailcall.c (dwarf2_tailcall_sniffer_first):
Update.
* dwarf2/loc.h (call_site_find_chain): Return unique_xmalloc_ptr.
* dwarf2/loc.c (call_site_find_chain_1): Return
unique_xmalloc_ptr.
(call_site_find_chain): Likewise.
