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cd4fb1b2 SM |
1 | /* DWARF 2 debugging format support for GDB. |
2 | ||
42a4f53d | 3 | Copyright (C) 1994-2019 Free Software Foundation, Inc. |
cd4fb1b2 SM |
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 | #ifndef DWARF2READ_H | |
21 | #define DWARF2READ_H | |
22 | ||
e4a62c65 | 23 | #include <unordered_map> |
87d6a7aa | 24 | #include "dwarf-index-cache.h" |
cd4fb1b2 SM |
25 | #include "filename-seen-cache.h" |
26 | #include "gdb_obstack.h" | |
268a13a5 | 27 | #include "gdbsupport/hash_enum.h" |
cd4fb1b2 | 28 | |
3c3bb058 AB |
29 | /* Hold 'maintenance (set|show) dwarf' commands. */ |
30 | extern struct cmd_list_element *set_dwarf_cmdlist; | |
31 | extern struct cmd_list_element *show_dwarf_cmdlist; | |
32 | ||
e86f08d2 CB |
33 | extern bool dwarf_always_disassemble; |
34 | ||
cd4fb1b2 SM |
35 | /* A descriptor for dwarf sections. |
36 | ||
37 | S.ASECTION, SIZE are typically initialized when the objfile is first | |
38 | scanned. BUFFER, READIN are filled in later when the section is read. | |
39 | If the section contained compressed data then SIZE is updated to record | |
40 | the uncompressed size of the section. | |
41 | ||
42 | DWP file format V2 introduces a wrinkle that is easiest to handle by | |
43 | creating the concept of virtual sections contained within a real section. | |
44 | In DWP V2 the sections of the input DWO files are concatenated together | |
45 | into one section, but section offsets are kept relative to the original | |
46 | input section. | |
47 | If this is a virtual dwp-v2 section, S.CONTAINING_SECTION is a backlink to | |
48 | the real section this "virtual" section is contained in, and BUFFER,SIZE | |
49 | describe the virtual section. */ | |
50 | ||
51 | struct dwarf2_section_info | |
52 | { | |
53 | union | |
54 | { | |
55 | /* If this is a real section, the bfd section. */ | |
56 | asection *section; | |
57 | /* If this is a virtual section, pointer to the containing ("real") | |
58 | section. */ | |
59 | struct dwarf2_section_info *containing_section; | |
60 | } s; | |
61 | /* Pointer to section data, only valid if readin. */ | |
62 | const gdb_byte *buffer; | |
63 | /* The size of the section, real or virtual. */ | |
64 | bfd_size_type size; | |
65 | /* If this is a virtual section, the offset in the real section. | |
66 | Only valid if is_virtual. */ | |
67 | bfd_size_type virtual_offset; | |
68 | /* True if we have tried to read this section. */ | |
dc4ccb6f | 69 | bool readin; |
cd4fb1b2 SM |
70 | /* True if this is a virtual section, False otherwise. |
71 | This specifies which of s.section and s.containing_section to use. */ | |
dc4ccb6f | 72 | bool is_virtual; |
cd4fb1b2 SM |
73 | }; |
74 | ||
cd4fb1b2 SM |
75 | /* Read the contents of the section INFO. |
76 | OBJFILE is the main object file, but not necessarily the file where | |
77 | the section comes from. E.g., for DWO files the bfd of INFO is the bfd | |
78 | of the DWO file. | |
79 | If the section is compressed, uncompress it before returning. */ | |
80 | ||
81 | void dwarf2_read_section (struct objfile *objfile, dwarf2_section_info *info); | |
82 | ||
83 | struct tu_stats | |
84 | { | |
85 | int nr_uniq_abbrev_tables; | |
86 | int nr_symtabs; | |
87 | int nr_symtab_sharers; | |
88 | int nr_stmt_less_type_units; | |
89 | int nr_all_type_units_reallocs; | |
90 | }; | |
91 | ||
92 | struct dwarf2_debug_sections; | |
93 | struct mapped_index; | |
94 | struct mapped_debug_names; | |
ff4c9fec | 95 | struct signatured_type; |
e4a62c65 TV |
96 | struct die_info; |
97 | typedef struct die_info *die_info_ptr; | |
cd4fb1b2 SM |
98 | |
99 | /* Collection of data recorded per objfile. | |
100 | This hangs off of dwarf2_objfile_data_key. */ | |
101 | ||
5bfd760d | 102 | struct dwarf2_per_objfile |
cd4fb1b2 SM |
103 | { |
104 | /* Construct a dwarf2_per_objfile for OBJFILE. NAMES points to the | |
105 | dwarf2 section names, or is NULL if the standard ELF names are | |
4b610737 TT |
106 | used. CAN_COPY is true for formats where symbol |
107 | interposition is possible and so symbol values must follow copy | |
108 | relocation rules. */ | |
cd4fb1b2 | 109 | dwarf2_per_objfile (struct objfile *objfile, |
4b610737 TT |
110 | const dwarf2_debug_sections *names, |
111 | bool can_copy); | |
cd4fb1b2 SM |
112 | |
113 | ~dwarf2_per_objfile (); | |
114 | ||
115 | DISABLE_COPY_AND_ASSIGN (dwarf2_per_objfile); | |
116 | ||
ff4c9fec SM |
117 | /* Return the CU/TU given its index. |
118 | ||
119 | This is intended for loops like: | |
120 | ||
121 | for (i = 0; i < (dwarf2_per_objfile->n_comp_units | |
122 | + dwarf2_per_objfile->n_type_units); ++i) | |
123 | { | |
124 | dwarf2_per_cu_data *per_cu = dwarf2_per_objfile->get_cutu (i); | |
125 | ||
126 | ...; | |
127 | } | |
128 | */ | |
129 | dwarf2_per_cu_data *get_cutu (int index); | |
130 | ||
131 | /* Return the CU given its index. | |
132 | This differs from get_cutu in that it's for when you know INDEX refers to a | |
133 | CU. */ | |
134 | dwarf2_per_cu_data *get_cu (int index); | |
135 | ||
136 | /* Return the TU given its index. | |
137 | This differs from get_cutu in that it's for when you know INDEX refers to a | |
138 | TU. */ | |
139 | signatured_type *get_tu (int index); | |
140 | ||
cd4fb1b2 SM |
141 | /* Free all cached compilation units. */ |
142 | void free_cached_comp_units (); | |
143 | private: | |
144 | /* This function is mapped across the sections and remembers the | |
145 | offset and size of each of the debugging sections we are | |
146 | interested in. */ | |
147 | void locate_sections (bfd *abfd, asection *sectp, | |
148 | const dwarf2_debug_sections &names); | |
149 | ||
150 | public: | |
151 | dwarf2_section_info info {}; | |
152 | dwarf2_section_info abbrev {}; | |
153 | dwarf2_section_info line {}; | |
154 | dwarf2_section_info loc {}; | |
155 | dwarf2_section_info loclists {}; | |
156 | dwarf2_section_info macinfo {}; | |
157 | dwarf2_section_info macro {}; | |
158 | dwarf2_section_info str {}; | |
159 | dwarf2_section_info line_str {}; | |
160 | dwarf2_section_info ranges {}; | |
161 | dwarf2_section_info rnglists {}; | |
162 | dwarf2_section_info addr {}; | |
163 | dwarf2_section_info frame {}; | |
164 | dwarf2_section_info eh_frame {}; | |
165 | dwarf2_section_info gdb_index {}; | |
166 | dwarf2_section_info debug_names {}; | |
167 | dwarf2_section_info debug_aranges {}; | |
168 | ||
fd5866f6 | 169 | std::vector<dwarf2_section_info> types; |
cd4fb1b2 SM |
170 | |
171 | /* Back link. */ | |
172 | struct objfile *objfile = NULL; | |
173 | ||
174 | /* Table of all the compilation units. This is used to locate | |
175 | the target compilation unit of a particular reference. */ | |
b76e467d | 176 | std::vector<dwarf2_per_cu_data *> all_comp_units; |
cd4fb1b2 | 177 | |
b2bdb8cf SM |
178 | /* The .debug_types-related CUs (TUs). */ |
179 | std::vector<signatured_type *> all_type_units; | |
cd4fb1b2 SM |
180 | |
181 | /* Table of struct type_unit_group objects. | |
182 | The hash key is the DW_AT_stmt_list value. */ | |
183 | htab_t type_unit_groups {}; | |
184 | ||
185 | /* A table mapping .debug_types signatures to its signatured_type entry. | |
186 | This is NULL if the .debug_types section hasn't been read in yet. */ | |
187 | htab_t signatured_types {}; | |
188 | ||
189 | /* Type unit statistics, to see how well the scaling improvements | |
190 | are doing. */ | |
191 | struct tu_stats tu_stats {}; | |
192 | ||
193 | /* A chain of compilation units that are currently read in, so that | |
194 | they can be freed later. */ | |
195 | dwarf2_per_cu_data *read_in_chain = NULL; | |
196 | ||
197 | /* A table mapping DW_AT_dwo_name values to struct dwo_file objects. | |
198 | This is NULL if the table hasn't been allocated yet. */ | |
51ac9db5 | 199 | htab_up dwo_files; |
cd4fb1b2 SM |
200 | |
201 | /* True if we've checked for whether there is a DWP file. */ | |
202 | bool dwp_checked = false; | |
203 | ||
204 | /* The DWP file if there is one, or NULL. */ | |
400174b1 | 205 | std::unique_ptr<struct dwp_file> dwp_file; |
cd4fb1b2 SM |
206 | |
207 | /* The shared '.dwz' file, if one exists. This is used when the | |
208 | original data was compressed using 'dwz -m'. */ | |
7ff8cb8c | 209 | std::unique_ptr<struct dwz_file> dwz_file; |
cd4fb1b2 | 210 | |
4b610737 TT |
211 | /* Whether copy relocations are supported by this object format. */ |
212 | bool can_copy; | |
213 | ||
cd4fb1b2 SM |
214 | /* A flag indicating whether this objfile has a section loaded at a |
215 | VMA of 0. */ | |
216 | bool has_section_at_zero = false; | |
217 | ||
218 | /* True if we are using the mapped index, | |
219 | or we are faking it for OBJF_READNOW's sake. */ | |
220 | bool using_index = false; | |
221 | ||
222 | /* The mapped index, or NULL if .gdb_index is missing or not being used. */ | |
3063847f | 223 | std::unique_ptr<mapped_index> index_table; |
cd4fb1b2 SM |
224 | |
225 | /* The mapped index, or NULL if .debug_names is missing or not being used. */ | |
226 | std::unique_ptr<mapped_debug_names> debug_names_table; | |
227 | ||
228 | /* When using index_table, this keeps track of all quick_file_names entries. | |
229 | TUs typically share line table entries with a CU, so we maintain a | |
230 | separate table of all line table entries to support the sharing. | |
231 | Note that while there can be way more TUs than CUs, we've already | |
232 | sorted all the TUs into "type unit groups", grouped by their | |
233 | DW_AT_stmt_list value. Therefore the only sharing done here is with a | |
234 | CU and its associated TU group if there is one. */ | |
235 | htab_t quick_file_names_table {}; | |
236 | ||
237 | /* Set during partial symbol reading, to prevent queueing of full | |
238 | symbols. */ | |
239 | bool reading_partial_symbols = false; | |
240 | ||
241 | /* Table mapping type DIEs to their struct type *. | |
242 | This is NULL if not allocated yet. | |
243 | The mapping is done via (CU/TU + DIE offset) -> type. */ | |
244 | htab_t die_type_hash {}; | |
245 | ||
246 | /* The CUs we recently read. */ | |
c5d0225d | 247 | std::vector<dwarf2_per_cu_data *> just_read_cus; |
cd4fb1b2 SM |
248 | |
249 | /* Table containing line_header indexed by offset and offset_in_dwz. */ | |
250 | htab_t line_header_hash {}; | |
251 | ||
252 | /* Table containing all filenames. This is an optional because the | |
253 | table is lazily constructed on first access. */ | |
254 | gdb::optional<filename_seen_cache> filenames_cache; | |
87d6a7aa SM |
255 | |
256 | /* If we loaded the index from an external file, this contains the | |
257 | resources associated to the open file, memory mapping, etc. */ | |
258 | std::unique_ptr<index_cache_resource> index_cache_res; | |
e4a62c65 TV |
259 | |
260 | /* Mapping from abstract origin DIE to concrete DIEs that reference it as | |
261 | DW_AT_abstract_origin. */ | |
f23f598e TV |
262 | std::unordered_map<sect_offset, std::vector<sect_offset>, \ |
263 | gdb::hash_enum<sect_offset>> \ | |
e4a62c65 | 264 | abstract_to_concrete; |
cd4fb1b2 SM |
265 | }; |
266 | ||
267 | /* Get the dwarf2_per_objfile associated to OBJFILE. */ | |
268 | ||
269 | dwarf2_per_objfile *get_dwarf2_per_objfile (struct objfile *objfile); | |
270 | ||
271 | /* Persistent data held for a compilation unit, even when not | |
272 | processing it. We put a pointer to this structure in the | |
273 | read_symtab_private field of the psymtab. */ | |
274 | ||
275 | struct dwarf2_per_cu_data | |
276 | { | |
277 | /* The start offset and length of this compilation unit. | |
278 | NOTE: Unlike comp_unit_head.length, this length includes | |
279 | initial_length_size. | |
280 | If the DIE refers to a DWO file, this is always of the original die, | |
281 | not the DWO file. */ | |
282 | sect_offset sect_off; | |
283 | unsigned int length; | |
284 | ||
285 | /* DWARF standard version this data has been read from (such as 4 or 5). */ | |
286 | short dwarf_version; | |
287 | ||
288 | /* Flag indicating this compilation unit will be read in before | |
289 | any of the current compilation units are processed. */ | |
290 | unsigned int queued : 1; | |
291 | ||
292 | /* This flag will be set when reading partial DIEs if we need to load | |
293 | absolutely all DIEs for this compilation unit, instead of just the ones | |
294 | we think are interesting. It gets set if we look for a DIE in the | |
295 | hash table and don't find it. */ | |
296 | unsigned int load_all_dies : 1; | |
297 | ||
298 | /* Non-zero if this CU is from .debug_types. | |
299 | Struct dwarf2_per_cu_data is contained in struct signatured_type iff | |
300 | this is non-zero. */ | |
301 | unsigned int is_debug_types : 1; | |
302 | ||
303 | /* Non-zero if this CU is from the .dwz file. */ | |
304 | unsigned int is_dwz : 1; | |
305 | ||
306 | /* Non-zero if reading a TU directly from a DWO file, bypassing the stub. | |
307 | This flag is only valid if is_debug_types is true. | |
308 | We can't read a CU directly from a DWO file: There are required | |
309 | attributes in the stub. */ | |
310 | unsigned int reading_dwo_directly : 1; | |
311 | ||
312 | /* Non-zero if the TU has been read. | |
313 | This is used to assist the "Stay in DWO Optimization" for Fission: | |
314 | When reading a DWO, it's faster to read TUs from the DWO instead of | |
315 | fetching them from random other DWOs (due to comdat folding). | |
316 | If the TU has already been read, the optimization is unnecessary | |
317 | (and unwise - we don't want to change where gdb thinks the TU lives | |
318 | "midflight"). | |
319 | This flag is only valid if is_debug_types is true. */ | |
320 | unsigned int tu_read : 1; | |
321 | ||
322 | /* The section this CU/TU lives in. | |
323 | If the DIE refers to a DWO file, this is always the original die, | |
324 | not the DWO file. */ | |
325 | struct dwarf2_section_info *section; | |
326 | ||
327 | /* Set to non-NULL iff this CU is currently loaded. When it gets freed out | |
328 | of the CU cache it gets reset to NULL again. This is left as NULL for | |
329 | dummy CUs (a CU header, but nothing else). */ | |
330 | struct dwarf2_cu *cu; | |
331 | ||
332 | /* The corresponding dwarf2_per_objfile. */ | |
333 | struct dwarf2_per_objfile *dwarf2_per_objfile; | |
334 | ||
335 | /* When dwarf2_per_objfile->using_index is true, the 'quick' field | |
336 | is active. Otherwise, the 'psymtab' field is active. */ | |
337 | union | |
338 | { | |
339 | /* The partial symbol table associated with this compilation unit, | |
340 | or NULL for unread partial units. */ | |
341 | struct partial_symtab *psymtab; | |
342 | ||
343 | /* Data needed by the "quick" functions. */ | |
344 | struct dwarf2_per_cu_quick_data *quick; | |
345 | } v; | |
346 | ||
ae640021 AB |
347 | /* Return true of IMPORTED_SYMTABS is empty or not yet allocated. */ |
348 | bool imported_symtabs_empty () const | |
349 | { | |
350 | return (imported_symtabs == nullptr || imported_symtabs->empty ()); | |
351 | } | |
352 | ||
353 | /* Push P to the back of IMPORTED_SYMTABS, allocated IMPORTED_SYMTABS | |
354 | first if required. */ | |
355 | void imported_symtabs_push (dwarf2_per_cu_data *p) | |
356 | { | |
357 | if (imported_symtabs == nullptr) | |
358 | imported_symtabs = new std::vector <dwarf2_per_cu_data *>; | |
359 | imported_symtabs->push_back (p); | |
360 | } | |
361 | ||
362 | /* Return the size of IMPORTED_SYMTABS if it is allocated, otherwise | |
363 | return 0. */ | |
364 | size_t imported_symtabs_size () const | |
365 | { | |
366 | if (imported_symtabs == nullptr) | |
367 | return 0; | |
368 | return imported_symtabs->size (); | |
369 | } | |
370 | ||
371 | /* Delete IMPORTED_SYMTABS and set the pointer back to nullptr. */ | |
372 | void imported_symtabs_free () | |
373 | { | |
374 | delete imported_symtabs; | |
375 | imported_symtabs = nullptr; | |
376 | } | |
377 | ||
cd4fb1b2 SM |
378 | /* The CUs we import using DW_TAG_imported_unit. This is filled in |
379 | while reading psymtabs, used to compute the psymtab dependencies, | |
380 | and then cleared. Then it is filled in again while reading full | |
381 | symbols, and only deleted when the objfile is destroyed. | |
382 | ||
383 | This is also used to work around a difference between the way gold | |
384 | generates .gdb_index version <=7 and the way gdb does. Arguably this | |
385 | is a gold bug. For symbols coming from TUs, gold records in the index | |
386 | the CU that includes the TU instead of the TU itself. This breaks | |
387 | dw2_lookup_symbol: It assumes that if the index says symbol X lives | |
388 | in CU/TU Y, then one need only expand Y and a subsequent lookup in Y | |
389 | will find X. Alas TUs live in their own symtab, so after expanding CU Y | |
390 | we need to look in TU Z to find X. Fortunately, this is akin to | |
391 | DW_TAG_imported_unit, so we just use the same mechanism: For | |
392 | .gdb_index version <=7 this also records the TUs that the CU referred | |
393 | to. Concurrently with this change gdb was modified to emit version 8 | |
394 | indices so we only pay a price for gold generated indices. | |
ae640021 AB |
395 | http://sourceware.org/bugzilla/show_bug.cgi?id=15021. |
396 | ||
397 | This currently needs to be a public member due to how | |
398 | dwarf2_per_cu_data is allocated and used. Ideally in future things | |
399 | could be refactored to make this private. Until then please try to | |
400 | avoid direct access to this member, and instead use the helper | |
401 | functions above. */ | |
402 | std::vector <dwarf2_per_cu_data *> *imported_symtabs; | |
cd4fb1b2 SM |
403 | }; |
404 | ||
405 | /* Entry in the signatured_types hash table. */ | |
406 | ||
407 | struct signatured_type | |
408 | { | |
409 | /* The "per_cu" object of this type. | |
410 | This struct is used iff per_cu.is_debug_types. | |
411 | N.B.: This is the first member so that it's easy to convert pointers | |
412 | between them. */ | |
413 | struct dwarf2_per_cu_data per_cu; | |
414 | ||
415 | /* The type's signature. */ | |
416 | ULONGEST signature; | |
417 | ||
418 | /* Offset in the TU of the type's DIE, as read from the TU header. | |
419 | If this TU is a DWO stub and the definition lives in a DWO file | |
420 | (specified by DW_AT_GNU_dwo_name), this value is unusable. */ | |
421 | cu_offset type_offset_in_tu; | |
422 | ||
423 | /* Offset in the section of the type's DIE. | |
424 | If the definition lives in a DWO file, this is the offset in the | |
425 | .debug_types.dwo section. | |
426 | The value is zero until the actual value is known. | |
427 | Zero is otherwise not a valid section offset. */ | |
428 | sect_offset type_offset_in_section; | |
429 | ||
430 | /* Type units are grouped by their DW_AT_stmt_list entry so that they | |
431 | can share them. This points to the containing symtab. */ | |
432 | struct type_unit_group *type_unit_group; | |
433 | ||
434 | /* The type. | |
435 | The first time we encounter this type we fully read it in and install it | |
436 | in the symbol tables. Subsequent times we only need the type. */ | |
437 | struct type *type; | |
438 | ||
439 | /* Containing DWO unit. | |
440 | This field is valid iff per_cu.reading_dwo_directly. */ | |
441 | struct dwo_unit *dwo_unit; | |
442 | }; | |
443 | ||
587ee17b TT |
444 | ULONGEST read_unsigned_leb128 (bfd *, const gdb_byte *, unsigned int *); |
445 | ||
c4973306 SM |
446 | /* This represents a '.dwz' file. */ |
447 | ||
448 | struct dwz_file | |
449 | { | |
450 | dwz_file (gdb_bfd_ref_ptr &&bfd) | |
451 | : dwz_bfd (std::move (bfd)) | |
452 | { | |
453 | } | |
454 | ||
455 | const char *filename () const | |
456 | { | |
00f93c44 | 457 | return bfd_get_filename (this->dwz_bfd.get ()); |
c4973306 SM |
458 | } |
459 | ||
460 | /* A dwz file can only contain a few sections. */ | |
461 | struct dwarf2_section_info abbrev {}; | |
462 | struct dwarf2_section_info info {}; | |
463 | struct dwarf2_section_info str {}; | |
464 | struct dwarf2_section_info line {}; | |
465 | struct dwarf2_section_info macro {}; | |
466 | struct dwarf2_section_info gdb_index {}; | |
467 | struct dwarf2_section_info debug_names {}; | |
468 | ||
469 | /* The dwz's BFD. */ | |
470 | gdb_bfd_ref_ptr dwz_bfd; | |
471 | ||
472 | /* If we loaded the index from an external file, this contains the | |
473 | resources associated to the open file, memory mapping, etc. */ | |
474 | std::unique_ptr<index_cache_resource> index_cache_res; | |
475 | }; | |
476 | ||
477 | /* Open the separate '.dwz' debug file, if needed. Return NULL if | |
478 | there is no .gnu_debugaltlink section in the file. Error if there | |
479 | is such a section but the file cannot be found. */ | |
480 | ||
481 | extern struct dwz_file *dwarf2_get_dwz_file | |
482 | (struct dwarf2_per_objfile *dwarf2_per_objfile); | |
483 | ||
cd4fb1b2 | 484 | #endif /* DWARF2READ_H */ |