1 /* DWARF 2 location expression support for GDB.
3 Copyright (C) 2003-2020 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
;
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 (struct 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 /* Evaluate a location description, starting at DATA and with length
57 SIZE, to find the current location of variable of TYPE in the context
60 struct value
*dwarf2_evaluate_loc_desc (struct type
*type
,
61 struct frame_info
*frame
,
64 struct dwarf2_per_cu_data
*per_cu
);
66 /* A chain of addresses that might be needed to resolve a dynamic
69 struct property_addr_info
71 /* The type of the object whose dynamic properties, if any, are
75 /* If not NULL, a buffer containing the object's value. */
76 gdb::array_view
<const gdb_byte
> valaddr
;
78 /* The address of that object. */
81 /* If not NULL, a pointer to the info for the object containing
82 the object described by this node. */
83 struct property_addr_info
*next
;
86 /* Converts a dynamic property into a static one. FRAME is the frame in which
87 the property is evaluated; if NULL, the selected frame (if any) is used
90 ADDR_STACK is the stack of addresses that might be needed to evaluate the
91 property. When evaluating a property that is not related to a type, it can
94 Returns true if PROP could be converted and the static value is passed
95 back into VALUE, otherwise returns false.
97 If PUSH_INITIAL_VALUE is true, then the top value of ADDR_STACK
98 will be pushed before evaluating a location expression. */
100 bool dwarf2_evaluate_property (const struct dynamic_prop
*prop
,
101 struct frame_info
*frame
,
102 const struct property_addr_info
*addr_stack
,
104 bool push_initial_value
= false);
106 /* A helper for the compiler interface that compiles a single dynamic
109 STREAM is where the C code is to be written.
110 RESULT_NAME is the name of the generated variable.
111 GDBARCH is the architecture to use.
112 REGISTERS_USED is a bit-vector that is filled to note which
113 registers are required by the generated expression.
114 PROP is the property for which code is generated.
115 ADDRESS is the address at which the property is considered to be
117 SYM the originating symbol, used for error reporting. */
119 void dwarf2_compile_property_to_c (string_file
*stream
,
120 const char *result_name
,
121 struct gdbarch
*gdbarch
,
122 unsigned char *registers_used
,
123 const struct dynamic_prop
*prop
,
127 /* The symbol location baton types used by the DWARF-2 reader (i.e.
128 SYMBOL_LOCATION_BATON for a LOC_COMPUTED symbol). "struct
129 dwarf2_locexpr_baton" is for a symbol with a single location
130 expression; "struct dwarf2_loclist_baton" is for a symbol with a
133 struct dwarf2_locexpr_baton
135 /* Pointer to the start of the location expression. Valid only if SIZE is
137 const gdb_byte
*data
;
139 /* Length of the location expression. For optimized out expressions it is
143 /* When true this location expression is a reference and actually
144 describes the address at which the value of the attribute can be
145 found. When false the expression provides the value of the attribute
149 /* The compilation unit containing the symbol whose location
151 struct dwarf2_per_cu_data
*per_cu
;
154 struct dwarf2_loclist_baton
156 /* The initial base address for the location list, based on the compilation
158 CORE_ADDR base_address
;
160 /* Pointer to the start of the location list. */
161 const gdb_byte
*data
;
163 /* Length of the location list. */
166 /* The compilation unit containing the symbol whose location
168 struct dwarf2_per_cu_data
*per_cu
;
170 /* Non-zero if the location list lives in .debug_loc.dwo.
171 The format of entries in this section are different. */
172 unsigned char from_dwo
;
175 /* The baton used when a dynamic property is an offset to a parent
176 type. This can be used, for instance, then the bound of an array
177 inside a record is determined by the value of another field inside
180 struct dwarf2_offset_baton
182 /* The offset from the parent type where the value of the property
183 is stored. In the example provided above, this would be the offset
184 of the field being used as the array bound. */
187 /* The type of the object whose property is dynamic. In the example
188 provided above, this would the array's index type. */
192 /* A dynamic property is either expressed as a single location expression
193 or a location list. If the property is an indirection, pointing to
194 another die, keep track of the targeted type in PROPERTY_TYPE.
195 Alternatively, if the property location gives the property value
196 directly then it will have PROPERTY_TYPE. */
198 struct dwarf2_property_baton
200 /* If the property is an indirection, we need to evaluate the location
201 in the context of the type PROPERTY_TYPE. If the property is supplied
202 by value then it will be of PROPERTY_TYPE. This field should never be
204 struct type
*property_type
;
207 /* Location expression either evaluated in the context of
208 PROPERTY_TYPE, or a value of type PROPERTY_TYPE. */
209 struct dwarf2_locexpr_baton locexpr
;
211 /* Location list to be evaluated in the context of PROPERTY_TYPE. */
212 struct dwarf2_loclist_baton loclist
;
214 /* The location is an offset to PROPERTY_TYPE. */
215 struct dwarf2_offset_baton offset_info
;
219 extern const struct symbol_computed_ops dwarf2_locexpr_funcs
;
220 extern const struct symbol_computed_ops dwarf2_loclist_funcs
;
222 extern const struct symbol_block_ops dwarf2_block_frame_base_locexpr_funcs
;
223 extern const struct symbol_block_ops dwarf2_block_frame_base_loclist_funcs
;
225 /* Determined tail calls for constructing virtual tail call frames. */
227 struct call_site_chain
229 /* Initially CALLERS == CALLEES == LENGTH. For partially ambiguous result
230 CALLERS + CALLEES < LENGTH. */
231 int callers
, callees
, length
;
233 /* Variably sized array with LENGTH elements. Later [0..CALLERS-1] contain
234 top (GDB "prev") sites and [LENGTH-CALLEES..LENGTH-1] contain bottom
235 (GDB "next") sites. One is interested primarily in the PC field. */
236 struct call_site
*call_site
[1];
239 struct call_site_stuff
;
240 extern gdb::unique_xmalloc_ptr
<call_site_chain
> call_site_find_chain
241 (struct gdbarch
*gdbarch
, CORE_ADDR caller_pc
, CORE_ADDR callee_pc
);
243 /* A helper function to convert a DWARF register to an arch register.
244 ARCH is the architecture.
245 DWARF_REG is the register.
246 If DWARF_REG is bad then a complaint is issued and -1 is returned.
247 Note: Some targets get this wrong. */
249 extern int dwarf_reg_to_regnum (struct gdbarch
*arch
, int dwarf_reg
);
251 /* A wrapper on dwarf_reg_to_regnum to throw an exception if the
252 DWARF register cannot be translated to an architecture register.
253 This takes a ULONGEST instead of an int because some callers actually have
254 a ULONGEST. Negative values passed as ints will still be flagged as
257 extern int dwarf_reg_to_regnum_or_error (struct gdbarch
*arch
,
260 #endif /* dwarf2loc.h */