gdb/dwarf2/read.h

   1 /* DWARF 2 debugging format support for GDB.
   2
   3    Copyright (C) 1994-2021 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 #ifndef DWARF2READ_H
  21 #define DWARF2READ_H
  22
  23 #include <queue>
  24 #include <unordered_map>
  25 #include "dwarf2/comp-unit-head.h"
  26 #include "dwarf2/index-cache.h"
  27 #include "dwarf2/section.h"
  28 #include "filename-seen-cache.h"
  29 #include "gdb_obstack.h"
  30 #include "gdbsupport/hash_enum.h"
  31 #include "gdbsupport/function-view.h"
  32 #include "psympriv.h"
  33
  34 /* Hold 'maintenance (set|show) dwarf' commands.  */
  35 extern struct cmd_list_element *set_dwarf_cmdlist;
  36 extern struct cmd_list_element *show_dwarf_cmdlist;
  37
  38 struct tu_stats
  39 {
  40   int nr_uniq_abbrev_tables;
  41   int nr_symtabs;
  42   int nr_symtab_sharers;
  43   int nr_stmt_less_type_units;
  44   int nr_all_type_units_reallocs;
  45   int nr_tus;
  46 };
  47
  48 struct dwarf2_cu;
  49 struct dwarf2_debug_sections;
  50 struct dwarf2_per_bfd;
  51 struct dwarf2_per_cu_data;
  52 struct dwarf2_psymtab;
  53 struct mapped_index;
  54 struct mapped_debug_names;
  55 struct signatured_type;
  56 struct type_unit_group;
  57
  58 /* One item on the queue of compilation units to read in full symbols
  59    for.  */
  60 struct dwarf2_queue_item
  61 {
  62   dwarf2_queue_item (dwarf2_per_cu_data *cu, dwarf2_per_objfile *per_objfile,
  63                      enum language lang)
  64     : per_cu (cu),
  65       per_objfile (per_objfile),
  66       pretend_language (lang)
  67   {
  68   }
  69
  70   ~dwarf2_queue_item ();
  71
  72   DISABLE_COPY_AND_ASSIGN (dwarf2_queue_item);
  73
  74   dwarf2_per_cu_data *per_cu;
  75   dwarf2_per_objfile *per_objfile;
  76   enum language pretend_language;
  77 };
  78
  79 /* A deleter for dwarf2_per_cu_data that knows to downcast to
  80    signatured_type as appropriate.  This approach lets us avoid a
  81    virtual destructor, which saves a bit of space.  */
  82
  83 struct dwarf2_per_cu_data_deleter
  84 {
  85   void operator() (dwarf2_per_cu_data *data);
  86 };
  87
  88 /* A specialization of unique_ptr for dwarf2_per_cu_data and
  89    subclasses.  */
  90 typedef std::unique_ptr<dwarf2_per_cu_data, dwarf2_per_cu_data_deleter>
  91     dwarf2_per_cu_data_up;
  92
  93 /* Persistent data held for a compilation unit, even when not
  94    processing it.  We put a pointer to this structure in the
  95    psymtab.  */
  96
  97 struct dwarf2_per_cu_data
  98 {
  99   dwarf2_per_cu_data ()
 100     : queued (false),
 101       is_debug_types (false),
 102       is_dwz (false),
 103       reading_dwo_directly (false),
 104       tu_read (false),
 105       m_header_read_in (false),
 106       unit_type {},
 107       lang (language_unknown)
 108   {
 109   }
 110
 111   /* The start offset and length of this compilation unit.
 112      NOTE: Unlike comp_unit_head.length, this length includes
 113      initial_length_size.
 114      If the DIE refers to a DWO file, this is always of the original die,
 115      not the DWO file.  */
 116   sect_offset sect_off {};
 117   unsigned int length = 0;
 118
 119   /* DWARF standard version this data has been read from (such as 4 or 5).  */
 120   unsigned char dwarf_version = 0;
 121
 122   /* Flag indicating this compilation unit will be read in before
 123      any of the current compilation units are processed.  */
 124   unsigned int queued : 1;
 125
 126   /* Non-zero if this CU is from .debug_types.
 127      Struct dwarf2_per_cu_data is contained in struct signatured_type iff
 128      this is non-zero.  */
 129   unsigned int is_debug_types : 1;
 130
 131   /* Non-zero if this CU is from the .dwz file.  */
 132   unsigned int is_dwz : 1;
 133
 134   /* Non-zero if reading a TU directly from a DWO file, bypassing the stub.
 135      This flag is only valid if is_debug_types is true.
 136      We can't read a CU directly from a DWO file: There are required
 137      attributes in the stub.  */
 138   unsigned int reading_dwo_directly : 1;
 139
 140   /* Non-zero if the TU has been read.
 141      This is used to assist the "Stay in DWO Optimization" for Fission:
 142      When reading a DWO, it's faster to read TUs from the DWO instead of
 143      fetching them from random other DWOs (due to comdat folding).
 144      If the TU has already been read, the optimization is unnecessary
 145      (and unwise - we don't want to change where gdb thinks the TU lives
 146      "midflight").
 147      This flag is only valid if is_debug_types is true.  */
 148   unsigned int tu_read : 1;
 149
 150   /* True if HEADER has been read in.
 151
 152      Don't access this field directly.  It should be private, but we can't make
 153      it private at the moment.  */
 154   mutable bool m_header_read_in : 1;
 155
 156   /* The unit type of this CU.  */
 157   ENUM_BITFIELD (dwarf_unit_type) unit_type : 8;
 158
 159   /* The language of this CU.  */
 160   ENUM_BITFIELD (language) lang : LANGUAGE_BITS;
 161
 162   /* Our index in the unshared "symtabs" vector.  */
 163   unsigned index = 0;
 164
 165   /* The section this CU/TU lives in.
 166      If the DIE refers to a DWO file, this is always the original die,
 167      not the DWO file.  */
 168   struct dwarf2_section_info *section = nullptr;
 169
 170   /* Backlink to the owner of this.  */
 171   dwarf2_per_bfd *per_bfd = nullptr;
 172
 173   /* DWARF header of this CU.  Note that dwarf2_cu reads its own version of the
 174      header, which may differ from this one, since it may pass rcuh_kind::TYPE
 175      to read_comp_unit_head, whereas for dwarf2_per_cu_data we always pass
 176      rcuh_kind::COMPILE.
 177
 178      Don't access this field directly, use the get_header method instead.  It
 179      should be private, but we can't make it private at the moment.  */
 180   mutable comp_unit_head m_header {};
 181
 182   /* When dwarf2_per_bfd::using_index is true, the 'quick' field
 183      is active.  Otherwise, the 'psymtab' field is active.  */
 184   union
 185   {
 186     /* The partial symbol table associated with this compilation unit,
 187        or NULL for unread partial units.  */
 188     dwarf2_psymtab *psymtab;
 189
 190     /* Data needed by the "quick" functions.  */
 191     struct dwarf2_per_cu_quick_data *quick;
 192   } v {};
 193
 194   /* The CUs we import using DW_TAG_imported_unit.  This is filled in
 195      while reading psymtabs, used to compute the psymtab dependencies,
 196      and then cleared.  Then it is filled in again while reading full
 197      symbols, and only deleted when the objfile is destroyed.
 198
 199      This is also used to work around a difference between the way gold
 200      generates .gdb_index version <=7 and the way gdb does.  Arguably this
 201      is a gold bug.  For symbols coming from TUs, gold records in the index
 202      the CU that includes the TU instead of the TU itself.  This breaks
 203      dw2_lookup_symbol: It assumes that if the index says symbol X lives
 204      in CU/TU Y, then one need only expand Y and a subsequent lookup in Y
 205      will find X.  Alas TUs live in their own symtab, so after expanding CU Y
 206      we need to look in TU Z to find X.  Fortunately, this is akin to
 207      DW_TAG_imported_unit, so we just use the same mechanism: For
 208      .gdb_index version <=7 this also records the TUs that the CU referred
 209      to.  Concurrently with this change gdb was modified to emit version 8
 210      indices so we only pay a price for gold generated indices.
 211      http://sourceware.org/bugzilla/show_bug.cgi?id=15021.
 212
 213      This currently needs to be a public member due to how
 214      dwarf2_per_cu_data is allocated and used.  Ideally in future things
 215      could be refactored to make this private.  Until then please try to
 216      avoid direct access to this member, and instead use the helper
 217      functions above.  */
 218   std::vector <dwarf2_per_cu_data *> *imported_symtabs = nullptr;
 219
 220   /* Return true of IMPORTED_SYMTABS is empty or not yet allocated.  */
 221   bool imported_symtabs_empty () const
 222   {
 223     return (imported_symtabs == nullptr || imported_symtabs->empty ());
 224   }
 225
 226   /* Push P to the back of IMPORTED_SYMTABS, allocated IMPORTED_SYMTABS
 227      first if required.  */
 228   void imported_symtabs_push (dwarf2_per_cu_data *p)
 229   {
 230     if (imported_symtabs == nullptr)
 231       imported_symtabs = new std::vector <dwarf2_per_cu_data *>;
 232     imported_symtabs->push_back (p);
 233   }
 234
 235   /* Return the size of IMPORTED_SYMTABS if it is allocated, otherwise
 236      return 0.  */
 237   size_t imported_symtabs_size () const
 238   {
 239     if (imported_symtabs == nullptr)
 240       return 0;
 241     return imported_symtabs->size ();
 242   }
 243
 244   /* Delete IMPORTED_SYMTABS and set the pointer back to nullptr.  */
 245   void imported_symtabs_free ()
 246   {
 247     delete imported_symtabs;
 248     imported_symtabs = nullptr;
 249   }
 250
 251   /* Get the header of this per_cu, reading it if necessary.  */
 252   const comp_unit_head *get_header () const;
 253
 254   /* Return the address size given in the compilation unit header for
 255      this CU.  */
 256   int addr_size () const;
 257
 258   /* Return the offset size given in the compilation unit header for
 259      this CU.  */
 260   int offset_size () const;
 261
 262   /* Return the DW_FORM_ref_addr size given in the compilation unit
 263      header for this CU.  */
 264   int ref_addr_size () const;
 265
 266   /* Return DWARF version number of this CU.  */
 267   short version () const
 268   {
 269     return dwarf_version;
 270   }
 271
 272   /* A type unit group has a per_cu object that is recognized by
 273      having no section.  */
 274   bool type_unit_group_p () const
 275   {
 276     return section == nullptr;
 277   }
 278
 279   /* Free any cached file names.  */
 280   void free_cached_file_names ();
 281 };
 282
 283 /* Entry in the signatured_types hash table.  */
 284
 285 struct signatured_type : public dwarf2_per_cu_data
 286 {
 287   signatured_type (ULONGEST signature)
 288     : signature (signature)
 289   {}
 290
 291   /* The type's signature.  */
 292   ULONGEST signature;
 293
 294   /* Offset in the TU of the type's DIE, as read from the TU header.
 295      If this TU is a DWO stub and the definition lives in a DWO file
 296      (specified by DW_AT_GNU_dwo_name), this value is unusable.  */
 297   cu_offset type_offset_in_tu {};
 298
 299   /* Offset in the section of the type's DIE.
 300      If the definition lives in a DWO file, this is the offset in the
 301      .debug_types.dwo section.
 302      The value is zero until the actual value is known.
 303      Zero is otherwise not a valid section offset.  */
 304   sect_offset type_offset_in_section {};
 305
 306   /* Type units are grouped by their DW_AT_stmt_list entry so that they
 307      can share them.  This points to the containing symtab.  */
 308   struct type_unit_group *type_unit_group = nullptr;
 309
 310   /* Containing DWO unit.
 311      This field is valid iff per_cu.reading_dwo_directly.  */
 312   struct dwo_unit *dwo_unit = nullptr;
 313 };
 314
 315 using signatured_type_up = std::unique_ptr<signatured_type>;
 316
 317 /* Some DWARF data can be shared across objfiles who share the same BFD,
 318    this data is stored in this object.
 319
 320    Two dwarf2_per_objfile objects representing objfiles sharing the same BFD
 321    will point to the same instance of dwarf2_per_bfd, unless the BFD requires
 322    relocation.  */
 323
 324 struct dwarf2_per_bfd
 325 {
 326   /* Construct a dwarf2_per_bfd for OBFD.  NAMES points to the
 327      dwarf2 section names, or is NULL if the standard ELF names are
 328      used.  CAN_COPY is true for formats where symbol
 329      interposition is possible and so symbol values must follow copy
 330      relocation rules.  */
 331   dwarf2_per_bfd (bfd *obfd, const dwarf2_debug_sections *names, bool can_copy);
 332
 333   ~dwarf2_per_bfd ();
 334
 335   DISABLE_COPY_AND_ASSIGN (dwarf2_per_bfd);
 336
 337   /* Return the CU given its index.  */
 338   dwarf2_per_cu_data *get_cu (int index) const
 339   {
 340     return this->all_comp_units[index].get ();
 341   }
 342
 343   /* A convenience function to allocate a dwarf2_per_cu_data.  The
 344      returned object has its "index" field set properly.  The object
 345      is allocated on the dwarf2_per_bfd obstack.  */
 346   dwarf2_per_cu_data_up allocate_per_cu ();
 347
 348   /* A convenience function to allocate a signatured_type.  The
 349      returned object has its "index" field set properly.  The object
 350      is allocated on the dwarf2_per_bfd obstack.  */
 351   signatured_type_up allocate_signatured_type (ULONGEST signature);
 352
 353 private:
 354   /* This function is mapped across the sections and remembers the
 355      offset and size of each of the debugging sections we are
 356      interested in.  */
 357   void locate_sections (bfd *abfd, asection *sectp,
 358                         const dwarf2_debug_sections &names);
 359
 360 public:
 361   /* The corresponding BFD.  */
 362   bfd *obfd;
 363
 364   /* Objects that can be shared across objfiles are stored in this
 365      obstack or on the psymtab obstack, while objects that are
 366      objfile-specific are stored on the objfile obstack.  */
 367   auto_obstack obstack;
 368
 369   dwarf2_section_info info {};
 370   dwarf2_section_info abbrev {};
 371   dwarf2_section_info line {};
 372   dwarf2_section_info loc {};
 373   dwarf2_section_info loclists {};
 374   dwarf2_section_info macinfo {};
 375   dwarf2_section_info macro {};
 376   dwarf2_section_info str {};
 377   dwarf2_section_info str_offsets {};
 378   dwarf2_section_info line_str {};
 379   dwarf2_section_info ranges {};
 380   dwarf2_section_info rnglists {};
 381   dwarf2_section_info addr {};
 382   dwarf2_section_info frame {};
 383   dwarf2_section_info eh_frame {};
 384   dwarf2_section_info gdb_index {};
 385   dwarf2_section_info debug_names {};
 386   dwarf2_section_info debug_aranges {};
 387
 388   std::vector<dwarf2_section_info> types;
 389
 390   /* Table of all the compilation units.  This is used to locate
 391      the target compilation unit of a particular reference.  */
 392   std::vector<dwarf2_per_cu_data_up> all_comp_units;
 393
 394   /* Table of struct type_unit_group objects.
 395      The hash key is the DW_AT_stmt_list value.  */
 396   htab_up type_unit_groups;
 397
 398   /* A table mapping .debug_types signatures to its signatured_type entry.
 399      This is NULL if the .debug_types section hasn't been read in yet.  */
 400   htab_up signatured_types;
 401
 402   /* Type unit statistics, to see how well the scaling improvements
 403      are doing.  */
 404   struct tu_stats tu_stats {};
 405
 406   /* A table mapping DW_AT_dwo_name values to struct dwo_file objects.
 407      This is NULL if the table hasn't been allocated yet.  */
 408   htab_up dwo_files;
 409
 410   /* True if we've checked for whether there is a DWP file.  */
 411   bool dwp_checked = false;
 412
 413   /* The DWP file if there is one, or NULL.  */
 414   std::unique_ptr<struct dwp_file> dwp_file;
 415
 416   /* The shared '.dwz' file, if one exists.  This is used when the
 417      original data was compressed using 'dwz -m'.  */
 418   std::unique_ptr<struct dwz_file> dwz_file;
 419
 420   /* Whether copy relocations are supported by this object format.  */
 421   bool can_copy;
 422
 423   /* A flag indicating whether this objfile has a section loaded at a
 424      VMA of 0.  */
 425   bool has_section_at_zero = false;
 426
 427   /* True if we are using the mapped index,
 428      or we are faking it for OBJF_READNOW's sake.  */
 429   bool using_index = false;
 430
 431   /* The mapped index, or NULL if .gdb_index is missing or not being used.  */
 432   std::unique_ptr<mapped_index> index_table;
 433
 434   /* The mapped index, or NULL if .debug_names is missing or not being used.  */
 435   std::unique_ptr<mapped_debug_names> debug_names_table;
 436
 437   /* When using index_table, this keeps track of all quick_file_names entries.
 438      TUs typically share line table entries with a CU, so we maintain a
 439      separate table of all line table entries to support the sharing.
 440      Note that while there can be way more TUs than CUs, we've already
 441      sorted all the TUs into "type unit groups", grouped by their
 442      DW_AT_stmt_list value.  Therefore the only sharing done here is with a
 443      CU and its associated TU group if there is one.  */
 444   htab_up quick_file_names_table;
 445
 446   /* Set during partial symbol reading, to prevent queueing of full
 447      symbols.  */
 448   bool reading_partial_symbols = false;
 449
 450   /* The CUs we recently read.  */
 451   std::vector<dwarf2_per_cu_data *> just_read_cus;
 452
 453   /* If we loaded the index from an external file, this contains the
 454      resources associated to the open file, memory mapping, etc.  */
 455   std::unique_ptr<index_cache_resource> index_cache_res;
 456
 457   /* Mapping from abstract origin DIE to concrete DIEs that reference it as
 458      DW_AT_abstract_origin.  */
 459   std::unordered_map<sect_offset, std::vector<sect_offset>,
 460                      gdb::hash_enum<sect_offset>>
 461     abstract_to_concrete;
 462
 463   /* CUs that are queued to be read.  */
 464   gdb::optional<std::queue<dwarf2_queue_item>> queue;
 465
 466   /* We keep a separate reference to the partial symtabs, in case we
 467      are sharing them between objfiles.  This is only set after
 468      partial symbols have been read the first time.  */
 469   std::shared_ptr<psymtab_storage> partial_symtabs;
 470
 471   /* The address map that is used by the DWARF index code.  */
 472   struct addrmap *index_addrmap = nullptr;
 473 };
 474
 475 /* This is the per-objfile data associated with a type_unit_group.  */
 476
 477 struct type_unit_group_unshareable
 478 {
 479   /* The compunit symtab.
 480      Type units in a group needn't all be defined in the same source file,
 481      so we create an essentially anonymous symtab as the compunit symtab.  */
 482   struct compunit_symtab *compunit_symtab = nullptr;
 483
 484   /* The number of symtabs from the line header.
 485      The value here must match line_header.num_file_names.  */
 486   unsigned int num_symtabs = 0;
 487
 488   /* The symbol tables for this TU (obtained from the files listed in
 489      DW_AT_stmt_list).
 490      WARNING: The order of entries here must match the order of entries
 491      in the line header.  After the first TU using this type_unit_group, the
 492      line header for the subsequent TUs is recreated from this.  This is done
 493      because we need to use the same symtabs for each TU using the same
 494      DW_AT_stmt_list value.  Also note that symtabs may be repeated here,
 495      there's no guarantee the line header doesn't have duplicate entries.  */
 496   struct symtab **symtabs = nullptr;
 497 };
 498
 499 /* Collection of data recorded per objfile.
 500    This hangs off of dwarf2_objfile_data_key.
 501
 502    Some DWARF data cannot (currently) be shared across objfiles.  Such
 503    data is stored in this object.  */
 504
 505 struct dwarf2_per_objfile
 506 {
 507   dwarf2_per_objfile (struct objfile *objfile, dwarf2_per_bfd *per_bfd)
 508     : objfile (objfile), per_bfd (per_bfd)
 509   {}
 510
 511   ~dwarf2_per_objfile ();
 512
 513   /* Return pointer to string at .debug_line_str offset as read from BUF.
 514      BUF is assumed to be in a compilation unit described by CU_HEADER.
 515      Return *BYTES_READ_PTR count of bytes read from BUF.  */
 516   const char *read_line_string (const gdb_byte *buf,
 517                                 const struct comp_unit_head *cu_header,
 518                                 unsigned int *bytes_read_ptr);
 519
 520   /* Return true if the symtab corresponding to PER_CU has been set,
 521      false otherwise.  */
 522   bool symtab_set_p (const dwarf2_per_cu_data *per_cu) const;
 523
 524   /* Return the compunit_symtab associated to PER_CU, if it has been created.  */
 525   compunit_symtab *get_symtab (const dwarf2_per_cu_data *per_cu) const;
 526
 527   /* Set the compunit_symtab associated to PER_CU.  */
 528   void set_symtab (const dwarf2_per_cu_data *per_cu, compunit_symtab *symtab);
 529
 530   /* Get the type_unit_group_unshareable corresponding to TU_GROUP.  If one
 531      does not exist, create it.  */
 532   type_unit_group_unshareable *get_type_unit_group_unshareable
 533     (type_unit_group *tu_group);
 534
 535   struct type *get_type_for_signatured_type (signatured_type *sig_type) const;
 536
 537   void set_type_for_signatured_type (signatured_type *sig_type,
 538                                      struct type *type);
 539
 540   /* Find an integer type SIZE_IN_BYTES bytes in size and return it.
 541      UNSIGNED_P controls if the integer is unsigned or not.  */
 542   struct type *int_type (int size_in_bytes, bool unsigned_p) const;
 543
 544   /* Get the dwarf2_cu matching PER_CU for this objfile.  */
 545   dwarf2_cu *get_cu (dwarf2_per_cu_data *per_cu);
 546
 547   /* Set the dwarf2_cu matching PER_CU for this objfile.  */
 548   void set_cu (dwarf2_per_cu_data *per_cu, dwarf2_cu *cu);
 549
 550   /* Remove/free the dwarf2_cu matching PER_CU for this objfile.  */
 551   void remove_cu (dwarf2_per_cu_data *per_cu);
 552
 553   /* Free all cached compilation units.  */
 554   void remove_all_cus ();
 555
 556   /* Increase the age counter on each CU compilation unit and free
 557      any that are too old.  */
 558   void age_comp_units ();
 559
 560   /* Back link.  */
 561   struct objfile *objfile;
 562
 563   /* Pointer to the data that is (possibly) shared between this objfile and
 564      other objfiles backed by the same BFD.  */
 565   struct dwarf2_per_bfd *per_bfd;
 566
 567   /* Table mapping type DIEs to their struct type *.
 568      This is nullptr if not allocated yet.
 569      The mapping is done via (CU/TU + DIE offset) -> type.  */
 570   htab_up die_type_hash;
 571
 572   /* Table containing line_header indexed by offset and offset_in_dwz.  */
 573   htab_up line_header_hash;
 574
 575   /* The CU containing the m_builder in scope.  */
 576   dwarf2_cu *sym_cu = nullptr;
 577
 578 private:
 579   /* Hold the corresponding compunit_symtab for each CU or TU.  This
 580      is indexed by dwarf2_per_cu_data::index.  A NULL value means
 581      that the CU/TU has not been expanded yet.  */
 582   std::vector<compunit_symtab *> m_symtabs;
 583
 584   /* Map from a type unit group to the corresponding unshared
 585      structure.  */
 586   typedef std::unique_ptr<type_unit_group_unshareable>
 587     type_unit_group_unshareable_up;
 588
 589   std::unordered_map<type_unit_group *, type_unit_group_unshareable_up>
 590     m_type_units;
 591
 592   /* Map from signatured types to the corresponding struct type.  */
 593   std::unordered_map<signatured_type *, struct type *> m_type_map;
 594
 595   /* Map from the objfile-independent dwarf2_per_cu_data instances to the
 596      corresponding objfile-dependent dwarf2_cu instances.  */
 597   std::unordered_map<dwarf2_per_cu_data *, dwarf2_cu *> m_dwarf2_cus;
 598 };
 599
 600 /* Get the dwarf2_per_objfile associated to OBJFILE.  */
 601
 602 dwarf2_per_objfile *get_dwarf2_per_objfile (struct objfile *objfile);
 603
 604 /* A partial symtab specialized for DWARF.  */
 605 struct dwarf2_psymtab : public partial_symtab
 606 {
 607   dwarf2_psymtab (const char *filename,
 608                   psymtab_storage *partial_symtabs,
 609                   objfile_per_bfd_storage *objfile_per_bfd,
 610                   dwarf2_per_cu_data *per_cu)
 611     : partial_symtab (filename, partial_symtabs, objfile_per_bfd, 0),
 612       per_cu_data (per_cu)
 613   {
 614   }
 615
 616   void read_symtab (struct objfile *) override;
 617   void expand_psymtab (struct objfile *) override;
 618   bool readin_p (struct objfile *) const override;
 619   compunit_symtab *get_compunit_symtab (struct objfile *) const override;
 620
 621   struct dwarf2_per_cu_data *per_cu_data;
 622 };
 623
 624 /* Return the type of the DIE at DIE_OFFSET in the CU named by
 625    PER_CU.  */
 626
 627 struct type *dwarf2_get_die_type (cu_offset die_offset,
 628                                   dwarf2_per_cu_data *per_cu,
 629                                   dwarf2_per_objfile *per_objfile);
 630
 631 /* Given an index in .debug_addr, fetch the value.
 632    NOTE: This can be called during dwarf expression evaluation,
 633    long after the debug information has been read, and thus per_cu->cu
 634    may no longer exist.  */
 635
 636 CORE_ADDR dwarf2_read_addr_index (dwarf2_per_cu_data *per_cu,
 637                                   dwarf2_per_objfile *per_objfile,
 638                                   unsigned int addr_index);
 639
 640 /* Return DWARF block referenced by DW_AT_location of DIE at SECT_OFF at PER_CU.
 641    Returned value is intended for DW_OP_call*.  Returned
 642    dwarf2_locexpr_baton->data has lifetime of
 643    PER_CU->DWARF2_PER_OBJFILE->OBJFILE.  */
 644
 645 struct dwarf2_locexpr_baton dwarf2_fetch_die_loc_sect_off
 646   (sect_offset sect_off, dwarf2_per_cu_data *per_cu,
 647    dwarf2_per_objfile *per_objfile,
 648    gdb::function_view<CORE_ADDR ()> get_frame_pc,
 649    bool resolve_abstract_p = false);
 650
 651 /* Like dwarf2_fetch_die_loc_sect_off, but take a CU
 652    offset.  */
 653
 654 struct dwarf2_locexpr_baton dwarf2_fetch_die_loc_cu_off
 655   (cu_offset offset_in_cu, dwarf2_per_cu_data *per_cu,
 656    dwarf2_per_objfile *per_objfile,
 657    gdb::function_view<CORE_ADDR ()> get_frame_pc);
 658
 659 /* If the DIE at SECT_OFF in PER_CU has a DW_AT_const_value, return a
 660    pointer to the constant bytes and set LEN to the length of the
 661    data.  If memory is needed, allocate it on OBSTACK.  If the DIE
 662    does not have a DW_AT_const_value, return NULL.  */
 663
 664 extern const gdb_byte *dwarf2_fetch_constant_bytes
 665   (sect_offset sect_off, dwarf2_per_cu_data *per_cu,
 666    dwarf2_per_objfile *per_objfile, obstack *obstack,
 667    LONGEST *len);
 668
 669 /* Return the type of the die at SECT_OFF in PER_CU.  Return NULL if no
 670    valid type for this die is found.  If VAR_NAME is non-null, and if
 671    the DIE in question is a variable declaration (definitions are
 672    excluded), then *VAR_NAME is set to the variable's name.  */
 673
 674 struct type *dwarf2_fetch_die_type_sect_off
 675   (sect_offset sect_off, dwarf2_per_cu_data *per_cu,
 676    dwarf2_per_objfile *per_objfile,
 677    const char **var_name = nullptr);
 678
 679 /* When non-zero, dump line number entries as they are read in.  */
 680 extern unsigned int dwarf_line_debug;
 681
 682 /* Dwarf2 sections that can be accessed by dwarf2_get_section_info.  */
 683 enum dwarf2_section_enum {
 684   DWARF2_DEBUG_FRAME,
 685   DWARF2_EH_FRAME
 686 };
 687
 688 extern void dwarf2_get_section_info (struct objfile *,
 689                                      enum dwarf2_section_enum,
 690                                      asection **, const gdb_byte **,
 691                                      bfd_size_type *);
 692
 693 #endif /* DWARF2READ_H */