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70454ee70a
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.
298 lines
10 KiB
C++
298 lines
10 KiB
C++
/* DWARF 2 location expression support for GDB.
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Copyright (C) 2003-2021 Free Software Foundation, Inc.
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This file is part of GDB.
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This program is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 3 of the License, or
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(at your option) any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program. If not, see <http://www.gnu.org/licenses/>. */
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#if !defined (DWARF2LOC_H)
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#define DWARF2LOC_H
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#include "dwarf2/expr.h"
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struct symbol_computed_ops;
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struct dwarf2_per_objfile;
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struct dwarf2_per_cu_data;
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struct dwarf2_loclist_baton;
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struct agent_expr;
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struct axs_value;
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/* This header is private to the DWARF-2 reader. It is shared between
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dwarf2read.c and dwarf2loc.c. */
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/* `set debug entry-values' setting. */
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extern unsigned int entry_values_debug;
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/* Find a particular location expression from a location list. */
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const gdb_byte *dwarf2_find_location_expression
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(struct dwarf2_loclist_baton *baton,
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size_t *locexpr_length,
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CORE_ADDR pc);
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/* Find the frame base information for FRAMEFUNC at PC. START is an
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out parameter which is set to point to the DWARF expression to
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compute. LENGTH is an out parameter which is set to the length of
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the DWARF expression. This throws an exception on error or if an
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expression is not found; the returned length will never be
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zero. */
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extern void func_get_frame_base_dwarf_block (struct symbol *framefunc,
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CORE_ADDR pc,
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const gdb_byte **start,
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size_t *length);
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/* A helper function to find the definition of NAME and compute its
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value. Returns nullptr if the name is not found. */
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value *compute_var_value (const char *name);
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/* Fetch call_site_parameter from caller matching KIND and KIND_U.
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FRAME is for callee.
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Function always returns non-NULL, it throws NO_ENTRY_VALUE_ERROR
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otherwise. */
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struct call_site_parameter *dwarf_expr_reg_to_entry_parameter
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(struct frame_info *frame, enum call_site_parameter_kind kind,
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union call_site_parameter_u kind_u, dwarf2_per_cu_data **per_cu_return,
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dwarf2_per_objfile **per_objfile_return);
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/* Evaluate a location description, starting at DATA and with length
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SIZE, to find the current location of variable of TYPE in the context
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of FRAME. AS_LVAL defines if the resulting struct value is expected to
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be a value or a location description. */
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struct value *dwarf2_evaluate_loc_desc (struct type *type,
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struct frame_info *frame,
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const gdb_byte *data,
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size_t size,
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dwarf2_per_cu_data *per_cu,
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dwarf2_per_objfile *per_objfile,
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bool as_lval = true);
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/* A chain of addresses that might be needed to resolve a dynamic
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property. */
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struct property_addr_info
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{
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/* The type of the object whose dynamic properties, if any, are
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being resolved. */
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struct type *type;
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/* If not NULL, a buffer containing the object's value. */
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gdb::array_view<const gdb_byte> valaddr;
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/* The address of that object. */
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CORE_ADDR addr;
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/* If not NULL, a pointer to the info for the object containing
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the object described by this node. */
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struct property_addr_info *next;
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};
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/* Converts a dynamic property into a static one. FRAME is the frame in which
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the property is evaluated; if NULL, the selected frame (if any) is used
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instead.
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ADDR_STACK is the stack of addresses that might be needed to evaluate the
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property. When evaluating a property that is not related to a type, it can
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be NULL.
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Returns true if PROP could be converted and the static value is passed
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back into VALUE, otherwise returns false.
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If PUSH_INITIAL_VALUE is true, then the top value of ADDR_STACK
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will be pushed before evaluating a location expression. */
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bool dwarf2_evaluate_property (const struct dynamic_prop *prop,
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struct frame_info *frame,
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const struct property_addr_info *addr_stack,
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CORE_ADDR *value,
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bool push_initial_value = false);
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/* A helper for the compiler interface that compiles a single dynamic
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property to C code.
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STREAM is where the C code is to be written.
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RESULT_NAME is the name of the generated variable.
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GDBARCH is the architecture to use.
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REGISTERS_USED is a bit-vector that is filled to note which
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registers are required by the generated expression.
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PROP is the property for which code is generated.
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ADDRESS is the address at which the property is considered to be
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evaluated.
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SYM the originating symbol, used for error reporting. */
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void dwarf2_compile_property_to_c (string_file *stream,
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const char *result_name,
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struct gdbarch *gdbarch,
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std::vector<bool> ®isters_used,
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const struct dynamic_prop *prop,
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CORE_ADDR address,
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struct symbol *sym);
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/* The symbol location baton types used by the DWARF-2 reader (i.e.
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SYMBOL_LOCATION_BATON for a LOC_COMPUTED symbol). "struct
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dwarf2_locexpr_baton" is for a symbol with a single location
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expression; "struct dwarf2_loclist_baton" is for a symbol with a
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location list. */
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struct dwarf2_locexpr_baton
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{
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/* Pointer to the start of the location expression. Valid only if SIZE is
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not zero. */
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const gdb_byte *data;
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/* Length of the location expression. For optimized out expressions it is
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zero. */
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size_t size;
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/* When true this location expression is a reference and actually
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describes the address at which the value of the attribute can be
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found. When false the expression provides the value of the attribute
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directly. */
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bool is_reference;
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/* The objfile that was used when creating this. */
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dwarf2_per_objfile *per_objfile;
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/* The compilation unit containing the symbol whose location
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we're computing. */
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struct dwarf2_per_cu_data *per_cu;
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};
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struct dwarf2_loclist_baton
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{
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/* The initial base address for the location list, based on the compilation
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unit. */
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CORE_ADDR base_address;
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/* Pointer to the start of the location list. */
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const gdb_byte *data;
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/* Length of the location list. */
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size_t size;
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/* The objfile that was used when creating this. */
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dwarf2_per_objfile *per_objfile;
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/* The compilation unit containing the symbol whose location
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we're computing. */
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struct dwarf2_per_cu_data *per_cu;
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/* Non-zero if the location list lives in .debug_loc.dwo.
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The format of entries in this section are different. */
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unsigned char from_dwo;
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};
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/* The baton used when a dynamic property is an offset to a parent
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type. This can be used, for instance, then the bound of an array
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inside a record is determined by the value of another field inside
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that record. */
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struct dwarf2_offset_baton
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{
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/* The offset from the parent type where the value of the property
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is stored. In the example provided above, this would be the offset
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of the field being used as the array bound. */
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LONGEST offset;
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/* The type of the object whose property is dynamic. In the example
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provided above, this would the array's index type. */
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struct type *type;
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};
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/* A dynamic property is either expressed as a single location expression
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or a location list. If the property is an indirection, pointing to
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another die, keep track of the targeted type in PROPERTY_TYPE.
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Alternatively, if the property location gives the property value
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directly then it will have PROPERTY_TYPE. */
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struct dwarf2_property_baton
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{
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/* If the property is an indirection, we need to evaluate the location
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in the context of the type PROPERTY_TYPE. If the property is supplied
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by value then it will be of PROPERTY_TYPE. This field should never be
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NULL. */
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struct type *property_type;
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union
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{
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/* Location expression either evaluated in the context of
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PROPERTY_TYPE, or a value of type PROPERTY_TYPE. */
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struct dwarf2_locexpr_baton locexpr;
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/* Location list to be evaluated in the context of PROPERTY_TYPE. */
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struct dwarf2_loclist_baton loclist;
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/* The location is an offset to PROPERTY_TYPE. */
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struct dwarf2_offset_baton offset_info;
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};
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};
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extern const struct symbol_computed_ops dwarf2_locexpr_funcs;
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extern const struct symbol_computed_ops dwarf2_loclist_funcs;
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extern const struct symbol_block_ops dwarf2_block_frame_base_locexpr_funcs;
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extern const struct symbol_block_ops dwarf2_block_frame_base_loclist_funcs;
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/* Determined tail calls for constructing virtual tail call frames. */
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struct call_site_chain
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{
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/* Initially CALLERS == CALLEES == LENGTH. For partially ambiguous result
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CALLERS + CALLEES < LENGTH. */
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int callers, callees, length;
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/* Variably sized array with LENGTH elements. Later [0..CALLERS-1] contain
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top (GDB "prev") sites and [LENGTH-CALLEES..LENGTH-1] contain bottom
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(GDB "next") sites. One is interested primarily in the PC field. */
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struct call_site *call_site[1];
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};
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extern gdb::unique_xmalloc_ptr<call_site_chain> call_site_find_chain
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(struct gdbarch *gdbarch, CORE_ADDR caller_pc, CORE_ADDR callee_pc);
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/* A helper function to convert a DWARF register to an arch register.
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ARCH is the architecture.
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DWARF_REG is the register.
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If DWARF_REG is bad then a complaint is issued and -1 is returned.
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Note: Some targets get this wrong. */
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extern int dwarf_reg_to_regnum (struct gdbarch *arch, int dwarf_reg);
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/* A wrapper on dwarf_reg_to_regnum to throw an exception if the
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DWARF register cannot be translated to an architecture register.
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This takes a ULONGEST instead of an int because some callers actually have
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a ULONGEST. Negative values passed as ints will still be flagged as
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invalid. */
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extern int dwarf_reg_to_regnum_or_error (struct gdbarch *arch,
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ULONGEST dwarf_reg);
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/* Helper function which throws an error if a synthetic pointer is
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invalid. */
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extern void invalid_synthetic_pointer ();
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/* Fetch the value pointed to by a synthetic pointer. */
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extern struct value *indirect_synthetic_pointer
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(sect_offset die, LONGEST byte_offset, dwarf2_per_cu_data *per_cu,
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dwarf2_per_objfile *per_objfile, struct frame_info *frame,
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struct type *type, bool resolve_abstract_p = false);
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#endif /* dwarf2loc.h */
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