1 /* DWARF 2 location expression support for GDB.
3 Copyright (C) 2003-2023 Free Software Foundation, Inc.
5 This file is part of GDB.
7 This program is free software; you can redistribute it and/or modify
8 it under the terms of the GNU General Public License as published by
9 the Free Software Foundation; either version 3 of the License, or
10 (at your option) any later version.
12 This program is distributed in the hope that it will be useful,
13 but WITHOUT ANY WARRANTY; without even the implied warranty of
14 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15 GNU General Public License for more details.
17 You should have received a copy of the GNU General Public License
18 along with this program. If not, see <http://www.gnu.org/licenses/>. */
20 #if !defined (DWARF2LOC_H)
23 #include "dwarf2/expr.h"
25 struct symbol_computed_ops
;
26 struct dwarf2_per_objfile
;
27 struct dwarf2_per_cu_data
;
28 struct dwarf2_loclist_baton
;
32 /* This header is private to the DWARF-2 reader. It is shared between
33 dwarf2read.c and dwarf2loc.c. */
35 /* `set debug entry-values' setting. */
36 extern unsigned int entry_values_debug
;
38 /* Find a particular location expression from a location list. */
39 const gdb_byte
*dwarf2_find_location_expression
40 (const dwarf2_loclist_baton
*baton
,
41 size_t *locexpr_length
,
44 /* Find the frame base information for FRAMEFUNC at PC. START is an
45 out parameter which is set to point to the DWARF expression to
46 compute. LENGTH is an out parameter which is set to the length of
47 the DWARF expression. This throws an exception on error or if an
48 expression is not found; the returned length will never be
51 extern void func_get_frame_base_dwarf_block (struct symbol
*framefunc
,
53 const gdb_byte
**start
,
56 /* A helper function to find the definition of NAME and compute its
57 value. Returns nullptr if the name is not found. */
59 value
*compute_var_value (const char *name
);
61 /* Fetch call_site_parameter from caller matching KIND and KIND_U.
64 Function always returns non-NULL, it throws NO_ENTRY_VALUE_ERROR
67 struct call_site_parameter
*dwarf_expr_reg_to_entry_parameter
68 (frame_info_ptr frame
, enum call_site_parameter_kind kind
,
69 union call_site_parameter_u kind_u
, dwarf2_per_cu_data
**per_cu_return
,
70 dwarf2_per_objfile
**per_objfile_return
);
73 /* Evaluate a location description, starting at DATA and with length
74 SIZE, to find the current location of variable of TYPE in the context
75 of FRAME. AS_LVAL defines if the resulting struct value is expected to
76 be a value or a location description. */
78 struct value
*dwarf2_evaluate_loc_desc (struct type
*type
,
82 dwarf2_per_cu_data
*per_cu
,
83 dwarf2_per_objfile
*per_objfile
,
86 /* A chain of addresses that might be needed to resolve a dynamic
89 struct property_addr_info
91 /* The type of the object whose dynamic properties, if any, are
95 /* If not NULL, a buffer containing the object's value. */
96 gdb::array_view
<const gdb_byte
> valaddr
;
98 /* The address of that object. */
101 /* If not NULL, a pointer to the info for the object containing
102 the object described by this node. */
103 struct property_addr_info
*next
;
106 /* Converts a dynamic property into a static one. FRAME is the frame in which
107 the property is evaluated; if NULL, the selected frame (if any) is used
110 ADDR_STACK is the stack of addresses that might be needed to evaluate the
111 property. When evaluating a property that is not related to a type, it can
114 Returns true if PROP could be converted and the static value is passed
115 back into VALUE, otherwise returns false.
117 Any values in PUSH_VALUES will be pushed before evaluating the location
118 expression, PUSH_VALUES[0] will be pushed first, then PUSH_VALUES[1],
119 etc. This means the during evaluation PUSH_VALUES[0] will be at the
120 bottom of the stack. */
122 bool dwarf2_evaluate_property (const struct dynamic_prop
*prop
,
123 frame_info_ptr frame
,
124 const struct property_addr_info
*addr_stack
,
126 gdb::array_view
<CORE_ADDR
> push_values
= {});
128 /* A helper for the compiler interface that compiles a single dynamic
131 STREAM is where the C code is to be written.
132 RESULT_NAME is the name of the generated variable.
133 GDBARCH is the architecture to use.
134 REGISTERS_USED is a bit-vector that is filled to note which
135 registers are required by the generated expression.
136 PROP is the property for which code is generated.
137 ADDRESS is the address at which the property is considered to be
139 SYM the originating symbol, used for error reporting. */
141 void dwarf2_compile_property_to_c (string_file
*stream
,
142 const char *result_name
,
143 struct gdbarch
*gdbarch
,
144 std::vector
<bool> ®isters_used
,
145 const struct dynamic_prop
*prop
,
149 /* The symbol location baton types used by the DWARF-2 reader (i.e.
150 SYMBOL_LOCATION_BATON for a LOC_COMPUTED symbol). "struct
151 dwarf2_locexpr_baton" is for a symbol with a single location
152 expression; "struct dwarf2_loclist_baton" is for a symbol with a
155 struct dwarf2_locexpr_baton
157 /* Pointer to the start of the location expression. Valid only if SIZE is
159 const gdb_byte
*data
;
161 /* Length of the location expression. For optimized out expressions it is
165 /* When true this location expression is a reference and actually
166 describes the address at which the value of the attribute can be
167 found. When false the expression provides the value of the attribute
171 /* The objfile that was used when creating this. */
172 dwarf2_per_objfile
*per_objfile
;
174 /* The compilation unit containing the symbol whose location
176 struct dwarf2_per_cu_data
*per_cu
;
179 struct dwarf2_loclist_baton
181 /* The initial base address for the location list, based on the compilation
183 unrelocated_addr base_address
;
185 /* Pointer to the start of the location list. */
186 const gdb_byte
*data
;
188 /* Length of the location list. */
191 /* The objfile that was used when creating this. */
192 dwarf2_per_objfile
*per_objfile
;
194 /* The compilation unit containing the symbol whose location
196 struct dwarf2_per_cu_data
*per_cu
;
198 /* Non-zero if the location list lives in .debug_loc.dwo.
199 The format of entries in this section are different. */
200 unsigned char from_dwo
;
203 /* The baton used when a dynamic property is an offset to a parent
204 type. This can be used, for instance, then the bound of an array
205 inside a record is determined by the value of another field inside
208 struct dwarf2_offset_baton
210 /* The offset from the parent type where the value of the property
211 is stored. In the example provided above, this would be the offset
212 of the field being used as the array bound. */
215 /* The type of the object whose property is dynamic. In the example
216 provided above, this would the array's index type. */
220 /* A dynamic property is either expressed as a single location expression
221 or a location list. If the property is an indirection, pointing to
222 another die, keep track of the targeted type in PROPERTY_TYPE.
223 Alternatively, if the property location gives the property value
224 directly then it will have PROPERTY_TYPE. */
226 struct dwarf2_property_baton
228 /* If the property is an indirection, we need to evaluate the location
229 in the context of the type PROPERTY_TYPE. If the property is supplied
230 by value then it will be of PROPERTY_TYPE. This field should never be
232 struct type
*property_type
;
235 /* Location expression either evaluated in the context of
236 PROPERTY_TYPE, or a value of type PROPERTY_TYPE. */
237 struct dwarf2_locexpr_baton locexpr
;
239 /* Location list to be evaluated in the context of PROPERTY_TYPE. */
240 struct dwarf2_loclist_baton loclist
;
242 /* The location is an offset to PROPERTY_TYPE. */
243 struct dwarf2_offset_baton offset_info
;
247 extern const struct symbol_computed_ops dwarf2_locexpr_funcs
;
248 extern const struct symbol_computed_ops dwarf2_loclist_funcs
;
249 extern const struct symbol_computed_ops ada_imported_funcs
;
251 extern const struct symbol_block_ops dwarf2_block_frame_base_locexpr_funcs
;
252 extern const struct symbol_block_ops dwarf2_block_frame_base_loclist_funcs
;
253 extern const struct symbol_block_ops ada_function_alias_funcs
;
255 /* Determined tail calls for constructing virtual tail call frames. */
257 struct call_site_chain
259 /* Initially CALLERS == CALLEES == LENGTH. For partially ambiguous result
260 CALLERS + CALLEES < LENGTH. */
261 int callers
, callees
, length
;
263 /* Variably sized array with LENGTH elements. Later [0..CALLERS-1] contain
264 top (GDB "prev") sites and [LENGTH-CALLEES..LENGTH-1] contain bottom
265 (GDB "next") sites. One is interested primarily in the PC field. */
266 struct call_site
*call_site
[1];
269 extern gdb::unique_xmalloc_ptr
<call_site_chain
> call_site_find_chain
270 (struct gdbarch
*gdbarch
, CORE_ADDR caller_pc
, CORE_ADDR callee_pc
);
272 /* A helper function to convert a DWARF register to an arch register.
273 ARCH is the architecture.
274 DWARF_REG is the register.
275 If DWARF_REG is bad then a complaint is issued and -1 is returned.
276 Note: Some targets get this wrong. */
278 extern int dwarf_reg_to_regnum (struct gdbarch
*arch
, int dwarf_reg
);
280 /* A wrapper on dwarf_reg_to_regnum to throw an exception if the
281 DWARF register cannot be translated to an architecture register.
282 This takes a ULONGEST instead of an int because some callers actually have
283 a ULONGEST. Negative values passed as ints will still be flagged as
286 extern int dwarf_reg_to_regnum_or_error (struct gdbarch
*arch
,
289 /* Helper function which throws an error if a synthetic pointer is
292 extern void invalid_synthetic_pointer ();
294 /* Fetch the value pointed to by a synthetic pointer. */
296 extern struct value
*indirect_synthetic_pointer
297 (sect_offset die
, LONGEST byte_offset
, dwarf2_per_cu_data
*per_cu
,
298 dwarf2_per_objfile
*per_objfile
, frame_info_ptr frame
,
299 struct type
*type
, bool resolve_abstract_p
= false);
301 /* Read parameter of TYPE at (callee) FRAME's function entry. KIND and KIND_U
302 are used to match DW_AT_location at the caller's
303 DW_TAG_call_site_parameter.
305 Function always returns non-NULL value. It throws NO_ENTRY_VALUE_ERROR if
306 it cannot resolve the parameter for any reason. */
308 extern struct value
*value_of_dwarf_reg_entry (struct type
*type
,
309 struct frame_info_ptr frame
,
310 enum call_site_parameter_kind kind
,
311 union call_site_parameter_u kind_u
);
312 #endif /* DWARF2LOC_H */