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loc.h
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1/* DWARF 2 location expression support for GDB.
2
3 Copyright (C) 2003-2023 Free Software Foundation, Inc.
4
5 This file is part of GDB.
6
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.
11
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.
16
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/>. */
19
20#if !defined (DWARF2LOC_H)
21#define DWARF2LOC_H
22
23#include "dwarf2/expr.h"
24
29struct agent_expr;
30struct axs_value;
31
32/* This header is private to the DWARF-2 reader. It is shared between
33 dwarf2read.c and dwarf2loc.c. */
34
35/* `set debug entry-values' setting. */
36extern unsigned int entry_values_debug;
37
38/* Find a particular location expression from a location list. */
40 (const dwarf2_loclist_baton *baton,
41 size_t *locexpr_length,
42 CORE_ADDR pc);
43
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
49 zero. */
50
51extern void func_get_frame_base_dwarf_block (struct symbol *framefunc,
52 CORE_ADDR pc,
53 const gdb_byte **start,
54 size_t *length);
55
56/* A helper function to find the definition of NAME and compute its
57 value. Returns nullptr if the name is not found. */
58
59value *compute_var_value (const char *name);
60
61/* Fetch call_site_parameter from caller matching KIND and KIND_U.
62 FRAME is for callee.
63
64 Function always returns non-NULL, it throws NO_ENTRY_VALUE_ERROR
65 otherwise. */
66
69 union call_site_parameter_u kind_u, dwarf2_per_cu_data **per_cu_return,
70 dwarf2_per_objfile **per_objfile_return);
71
72
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. */
77
79 frame_info_ptr frame,
80 const gdb_byte *data,
81 size_t size,
82 dwarf2_per_cu_data *per_cu,
83 dwarf2_per_objfile *per_objfile,
84 bool as_lval = true);
85
86/* A chain of addresses that might be needed to resolve a dynamic
87 property. */
88
90{
91 /* The type of the object whose dynamic properties, if any, are
92 being resolved. */
93 struct type *type;
94
95 /* If not NULL, a buffer containing the object's value. */
96 gdb::array_view<const gdb_byte> valaddr;
97
98 /* The address of that object. */
99 CORE_ADDR addr;
100
101 /* If not NULL, a pointer to the info for the object containing
102 the object described by this node. */
104};
105
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
108 instead.
109
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
112 be NULL.
113
114 Returns true if PROP could be converted and the static value is passed
115 back into VALUE, otherwise returns false.
116
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. */
121
122bool dwarf2_evaluate_property (const struct dynamic_prop *prop,
123 frame_info_ptr frame,
124 const struct property_addr_info *addr_stack,
125 CORE_ADDR *value,
126 gdb::array_view<CORE_ADDR> push_values = {});
127
128/* A helper for the compiler interface that compiles a single dynamic
129 property to C code.
130
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
138 evaluated.
139 SYM the originating symbol, used for error reporting. */
140
142 const char *result_name,
143 struct gdbarch *gdbarch,
144 std::vector<bool> &registers_used,
145 const struct dynamic_prop *prop,
146 CORE_ADDR address,
147 struct symbol *sym);
148
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
153 location list. */
154
156{
157 /* Pointer to the start of the location expression. Valid only if SIZE is
158 not zero. */
159 const gdb_byte *data;
160
161 /* Length of the location expression. For optimized out expressions it is
162 zero. */
163 size_t size;
164
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
168 directly. */
170
171 /* The objfile that was used when creating this. */
173
174 /* The compilation unit containing the symbol whose location
175 we're computing. */
177};
178
180{
181 /* The initial base address for the location list, based on the compilation
182 unit. */
183 unrelocated_addr base_address;
184
185 /* Pointer to the start of the location list. */
186 const gdb_byte *data;
187
188 /* Length of the location list. */
189 size_t size;
190
191 /* The objfile that was used when creating this. */
193
194 /* The compilation unit containing the symbol whose location
195 we're computing. */
197
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;
201};
202
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
206 that record. */
207
209{
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. */
213 LONGEST offset;
214
215 /* The type of the object whose property is dynamic. In the example
216 provided above, this would the array's index type. */
217 struct type *type;
218};
219
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. */
225
227{
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
231 NULL. */
233 union
234 {
235 /* Location expression either evaluated in the context of
236 PROPERTY_TYPE, or a value of type PROPERTY_TYPE. */
238
239 /* Location list to be evaluated in the context of PROPERTY_TYPE. */
241
242 /* The location is an offset to PROPERTY_TYPE. */
244 };
245};
246
247extern const struct symbol_computed_ops dwarf2_locexpr_funcs;
248extern const struct symbol_computed_ops dwarf2_loclist_funcs;
249extern const struct symbol_computed_ops ada_imported_funcs;
250
254
255/* Determined tail calls for constructing virtual tail call frames. */
256
258 {
259 /* Initially CALLERS == CALLEES == LENGTH. For partially ambiguous result
260 CALLERS + CALLEES < LENGTH. */
262
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. */
267 };
268
269extern gdb::unique_xmalloc_ptr<call_site_chain> call_site_find_chain
270 (struct gdbarch *gdbarch, CORE_ADDR caller_pc, CORE_ADDR callee_pc);
271
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. */
277
278extern int dwarf_reg_to_regnum (struct gdbarch *arch, int dwarf_reg);
279
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
284 invalid. */
285
286extern int dwarf_reg_to_regnum_or_error (struct gdbarch *arch,
287 ULONGEST dwarf_reg);
288
289/* Helper function which throws an error if a synthetic pointer is
290 invalid. */
291
292extern void invalid_synthetic_pointer ();
293
294/* Fetch the value pointed to by a synthetic pointer. */
295
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);
300
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.
304
305 Function always returns non-NULL value. It throws NO_ENTRY_VALUE_ERROR if
306 it cannot resolve the parameter for any reason. */
307
308extern 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 */
const char *const name
call_site_parameter_kind
Definition call-site.h:36
size_t size
Definition go32-nat.c:239
void invalid_synthetic_pointer()
Definition loc.c:96
const struct symbol_block_ops ada_function_alias_funcs
struct call_site_parameter * dwarf_expr_reg_to_entry_parameter(frame_info_ptr frame, enum call_site_parameter_kind kind, union call_site_parameter_u kind_u, dwarf2_per_cu_data **per_cu_return, dwarf2_per_objfile **per_objfile_return)
Definition loc.c:1141
struct value * value_of_dwarf_reg_entry(struct type *type, struct frame_info_ptr frame, enum call_site_parameter_kind kind, union call_site_parameter_u kind_u)
Definition loc.c:1342
unsigned int entry_values_debug
Definition loc.c:636
struct value * indirect_synthetic_pointer(sect_offset die, LONGEST byte_offset, dwarf2_per_cu_data *per_cu, dwarf2_per_objfile *per_objfile, frame_info_ptr frame, struct type *type, bool resolve_abstract_p=false)
Definition loc.c:1456
const struct symbol_computed_ops dwarf2_loclist_funcs
Definition loc.c:4110
gdb::unique_xmalloc_ptr< call_site_chain > call_site_find_chain(struct gdbarch *gdbarch, CORE_ADDR caller_pc, CORE_ADDR callee_pc)
Definition loc.c:1091
int dwarf_reg_to_regnum(struct gdbarch *arch, int dwarf_reg)
Definition loc.c:2275
const struct symbol_computed_ops dwarf2_locexpr_funcs
Definition loc.c:3870
int dwarf_reg_to_regnum_or_error(struct gdbarch *arch, ULONGEST dwarf_reg)
Definition loc.c:2304
struct value * dwarf2_evaluate_loc_desc(struct type *type, frame_info_ptr frame, const gdb_byte *data, size_t size, dwarf2_per_cu_data *per_cu, dwarf2_per_objfile *per_objfile, bool as_lval=true)
Definition loc.c:1564
value * compute_var_value(const char *name)
Definition loc.c:625
const struct symbol_block_ops dwarf2_block_frame_base_locexpr_funcs
Definition loc.c:539
void func_get_frame_base_dwarf_block(struct symbol *framefunc, CORE_ADDR pc, const gdb_byte **start, size_t *length)
Definition loc.c:605
const struct symbol_computed_ops ada_imported_funcs
void dwarf2_compile_property_to_c(string_file *stream, const char *result_name, struct gdbarch *gdbarch, std::vector< bool > &registers_used, const struct dynamic_prop *prop, CORE_ADDR address, struct symbol *sym)
Definition loc.c:1783
const gdb_byte * dwarf2_find_location_expression(const dwarf2_loclist_baton *baton, size_t *locexpr_length, CORE_ADDR pc)
Definition loc.c:365
bool dwarf2_evaluate_property(const struct dynamic_prop *prop, frame_info_ptr frame, const struct property_addr_info *addr_stack, CORE_ADDR *value, gdb::array_view< CORE_ADDR > push_values={})
Definition loc.c:1647
const struct symbol_block_ops dwarf2_block_frame_base_loclist_funcs
Definition loc.c:596
int callers
Definition loc.h:261
int callees
Definition loc.h:261
__extension__ enum call_site_parameter_kind kind
Definition call-site.h:145
struct dwarf2_per_cu_data * per_cu
Definition loc.h:176
const gdb_byte * data
Definition loc.h:159
dwarf2_per_objfile * per_objfile
Definition loc.h:172
struct dwarf2_per_cu_data * per_cu
Definition loc.h:196
unrelocated_addr base_address
Definition loc.h:183
unsigned char from_dwo
Definition loc.h:200
dwarf2_per_objfile * per_objfile
Definition loc.h:192
const gdb_byte * data
Definition loc.h:186
LONGEST offset
Definition loc.h:213
struct type * type
Definition loc.h:217
struct dwarf2_offset_baton offset_info
Definition loc.h:243
struct dwarf2_locexpr_baton locexpr
Definition loc.h:237
struct dwarf2_loclist_baton loclist
Definition loc.h:240
struct type * property_type
Definition loc.h:232
gdb::array_view< const gdb_byte > valaddr
Definition loc.h:96
struct type * type
Definition loc.h:93
CORE_ADDR addr
Definition loc.h:99
struct property_addr_info * next
Definition loc.h:103
Definition value.h:130