gdb/dwarf2/read.h

   1 /* DWARF 2 debugging format support for GDB.
   2
   3    Copyright (C) 1994-2022 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/file-and-dir.h"
  27 #include "dwarf2/index-cache.h"
  28 #include "dwarf2/section.h"
  29 #include "filename-seen-cache.h"
  30 #include "gdbsupport/gdb_obstack.h"
  31 #include "gdbsupport/hash_enum.h"
  32 #include "gdbsupport/function-view.h"
  33 #include "psympriv.h"
  34
  35 /* Hold 'maintenance (set|show) dwarf' commands.  */
  36 extern struct cmd_list_element *set_dwarf_cmdlist;
  37 extern struct cmd_list_element *show_dwarf_cmdlist;
  38
  39 struct tu_stats
  40 {
  41   int nr_uniq_abbrev_tables;
  42   int nr_symtabs;
  43   int nr_symtab_sharers;
  44   int nr_stmt_less_type_units;
  45   int nr_all_type_units_reallocs;
  46   int nr_tus;
  47 };
  48
  49 struct dwarf2_cu;
  50 struct dwarf2_debug_sections;
  51 struct dwarf2_per_bfd;
  52 struct dwarf2_per_cu_data;
  53 struct dwarf2_psymtab;
  54 struct mapped_index;
  55 struct mapped_debug_names;
  56 struct signatured_type;
  57 struct type_unit_group;
  58
  59 /* One item on the queue of compilation units to read in full symbols
  60    for.  */
  61 struct dwarf2_queue_item
  62 {
  63   dwarf2_queue_item (dwarf2_per_cu_data *cu, dwarf2_per_objfile *per_objfile,
  64                      enum language lang)
  65     : per_cu (cu),
  66       per_objfile (per_objfile),
  67       pretend_language (lang)
  68   {
  69   }
  70
  71   ~dwarf2_queue_item ();
  72
  73   DISABLE_COPY_AND_ASSIGN (dwarf2_queue_item);
  74
  75   dwarf2_per_cu_data *per_cu;
  76   dwarf2_per_objfile *per_objfile;
  77   enum language pretend_language;
  78 };
  79
  80 /* A deleter for dwarf2_per_cu_data that knows to downcast to
  81    signatured_type as appropriate.  This approach lets us avoid a
  82    virtual destructor, which saves a bit of space.  */
  83
  84 struct dwarf2_per_cu_data_deleter
  85 {
  86   void operator() (dwarf2_per_cu_data *data);
  87 };
  88
  89 /* A specialization of unique_ptr for dwarf2_per_cu_data and
  90    subclasses.  */
  91 typedef std::unique_ptr<dwarf2_per_cu_data, dwarf2_per_cu_data_deleter>
  92     dwarf2_per_cu_data_up;
  93
  94 /* Persistent data held for a compilation unit, even when not
  95    processing it.  We put a pointer to this structure in the
  96    psymtab.  */
  97
  98 struct dwarf2_per_cu_data
  99 {
 100   dwarf2_per_cu_data ()
 101     : queued (false),
 102       is_debug_types (false),
 103       is_dwz (false),
 104       reading_dwo_directly (false),
 105       tu_read (false),
 106       m_header_read_in (false),
 107       unit_type {},
 108       lang (language_unknown)
 109   {
 110   }
 111
 112   /* The start offset and length of this compilation unit.
 113      NOTE: Unlike comp_unit_head.length, this length includes
 114      initial_length_size.
 115      If the DIE refers to a DWO file, this is always of the original die,
 116      not the DWO file.  */
 117   sect_offset sect_off {};
 118   unsigned int length = 0;
 119
 120   /* DWARF standard version this data has been read from (such as 4 or 5).  */
 121   unsigned char dwarf_version = 0;
 122
 123   /* Flag indicating this compilation unit will be read in before
 124      any of the current compilation units are processed.  */
 125   unsigned int queued : 1;
 126
 127   /* Non-zero if this CU is from .debug_types.
 128      Struct dwarf2_per_cu_data is contained in struct signatured_type iff
 129      this is non-zero.  */
 130   unsigned int is_debug_types : 1;
 131
 132   /* Non-zero if this CU is from the .dwz file.  */
 133   unsigned int is_dwz : 1;
 134
 135   /* Non-zero if reading a TU directly from a DWO file, bypassing the stub.
 136      This flag is only valid if is_debug_types is true.
 137      We can't read a CU directly from a DWO file: There are required
 138      attributes in the stub.  */
 139   unsigned int reading_dwo_directly : 1;
 140
 141   /* Non-zero if the TU has been read.
 142      This is used to assist the "Stay in DWO Optimization" for Fission:
 143      When reading a DWO, it's faster to read TUs from the DWO instead of
 144      fetching them from random other DWOs (due to comdat folding).
 145      If the TU has already been read, the optimization is unnecessary
 146      (and unwise - we don't want to change where gdb thinks the TU lives
 147      "midflight").
 148      This flag is only valid if is_debug_types is true.  */
 149   unsigned int tu_read : 1;
 150
 151   /* True if HEADER has been read in.
 152
 153      Don't access this field directly.  It should be private, but we can't make
 154      it private at the moment.  */
 155   mutable bool m_header_read_in : 1;
 156
 157   /* The unit type of this CU.  */
 158   ENUM_BITFIELD (dwarf_unit_type) unit_type : 8;
 159
 160   /* The language of this CU.  */
 161   ENUM_BITFIELD (language) lang : LANGUAGE_BITS;
 162
 163   /* Our index in the unshared "symtabs" vector.  */
 164   unsigned index = 0;
 165
 166   /* The section this CU/TU lives in.
 167      If the DIE refers to a DWO file, this is always the original die,
 168      not the DWO file.  */
 169   struct dwarf2_section_info *section = nullptr;
 170
 171   /* Backlink to the owner of this.  */
 172   dwarf2_per_bfd *per_bfd = nullptr;
 173
 174   /* DWARF header of this CU.  Note that dwarf2_cu reads its own version of the
 175      header, which may differ from this one, since it may pass rcuh_kind::TYPE
 176      to read_comp_unit_head, whereas for dwarf2_per_cu_data we always pass
 177      rcuh_kind::COMPILE.
 178
 179      Don't access this field directly, use the get_header method instead.  It
 180      should be private, but we can't make it private at the moment.  */
 181   mutable comp_unit_head m_header {};
 182
 183   /* The file and directory for this CU.  This is cached so that we
 184      don't need to re-examine the DWO in some situations.  This may be
 185      nullptr, depending on the CU; for example a partial unit won't
 186      have one.  */
 187   std::unique_ptr<file_and_directory> fnd;
 188
 189   /* When dwarf2_per_bfd::using_index is true, the 'quick' field
 190      is active.  Otherwise, the 'psymtab' field is active.  */
 191   union
 192   {
 193     /* The partial symbol table associated with this compilation unit,
 194        or NULL for unread partial units.  */
 195     dwarf2_psymtab *psymtab;
 196
 197     /* Data needed by the "quick" functions.  */
 198     struct dwarf2_per_cu_quick_data *quick;
 199   } v {};
 200
 201   /* The CUs we import using DW_TAG_imported_unit.  This is filled in
 202      while reading psymtabs, used to compute the psymtab dependencies,
 203      and then cleared.  Then it is filled in again while reading full
 204      symbols, and only deleted when the objfile is destroyed.
 205
 206      This is also used to work around a difference between the way gold
 207      generates .gdb_index version <=7 and the way gdb does.  Arguably this
 208      is a gold bug.  For symbols coming from TUs, gold records in the index
 209      the CU that includes the TU instead of the TU itself.  This breaks
 210      dw2_lookup_symbol: It assumes that if the index says symbol X lives
 211      in CU/TU Y, then one need only expand Y and a subsequent lookup in Y
 212      will find X.  Alas TUs live in their own symtab, so after expanding CU Y
 213      we need to look in TU Z to find X.  Fortunately, this is akin to
 214      DW_TAG_imported_unit, so we just use the same mechanism: For
 215      .gdb_index version <=7 this also records the TUs that the CU referred
 216      to.  Concurrently with this change gdb was modified to emit version 8
 217      indices so we only pay a price for gold generated indices.
 218      http://sourceware.org/bugzilla/show_bug.cgi?id=15021.
 219
 220      This currently needs to be a public member due to how
 221      dwarf2_per_cu_data is allocated and used.  Ideally in future things
 222      could be refactored to make this private.  Until then please try to
 223      avoid direct access to this member, and instead use the helper
 224      functions above.  */
 225   std::vector <dwarf2_per_cu_data *> *imported_symtabs = nullptr;
 226
 227   /* Return true of IMPORTED_SYMTABS is empty or not yet allocated.  */
 228   bool imported_symtabs_empty () const
 229   {
 230     return (imported_symtabs == nullptr || imported_symtabs->empty ());
 231   }
 232
 233   /* Push P to the back of IMPORTED_SYMTABS, allocated IMPORTED_SYMTABS
 234      first if required.  */
 235   void imported_symtabs_push (dwarf2_per_cu_data *p)
 236   {
 237     if (imported_symtabs == nullptr)
 238       imported_symtabs = new std::vector <dwarf2_per_cu_data *>;
 239     imported_symtabs->push_back (p);
 240   }
 241
 242   /* Return the size of IMPORTED_SYMTABS if it is allocated, otherwise
 243      return 0.  */
 244   size_t imported_symtabs_size () const
 245   {
 246     if (imported_symtabs == nullptr)
 247       return 0;
 248     return imported_symtabs->size ();
 249   }
 250
 251   /* Delete IMPORTED_SYMTABS and set the pointer back to nullptr.  */
 252   void imported_symtabs_free ()
 253   {
 254     delete imported_symtabs;
 255     imported_symtabs = nullptr;
 256   }
 257
 258   /* Get the header of this per_cu, reading it if necessary.  */
 259   const comp_unit_head *get_header () const;
 260
 261   /* Return the address size given in the compilation unit header for
 262      this CU.  */
 263   int addr_size () const;
 264
 265   /* Return the offset size given in the compilation unit header for
 266      this CU.  */
 267   int offset_size () const;
 268
 269   /* Return the DW_FORM_ref_addr size given in the compilation unit
 270      header for this CU.  */
 271   int ref_addr_size () const;
 272
 273   /* Return DWARF version number of this CU.  */
 274   short version () const
 275   {
 276     return dwarf_version;
 277   }
 278
 279   /* A type unit group has a per_cu object that is recognized by
 280      having no section.  */
 281   bool type_unit_group_p () const
 282   {
 283     return section == nullptr;
 284   }
 285
 286   /* Free any cached file names.  */
 287   void free_cached_file_names ();
 288 };
 289
 290 /* Entry in the signatured_types hash table.  */
 291
 292 struct signatured_type : public dwarf2_per_cu_data
 293 {
 294   signatured_type (ULONGEST signature)
 295     : signature (signature)
 296   {}
 297
 298   /* The type's signature.  */
 299   ULONGEST signature;
 300
 301   /* Offset in the TU of the type's DIE, as read from the TU header.
 302      If this TU is a DWO stub and the definition lives in a DWO file
 303      (specified by DW_AT_GNU_dwo_name), this value is unusable.  */
 304   cu_offset type_offset_in_tu {};
 305
 306   /* Offset in the section of the type's DIE.
 307      If the definition lives in a DWO file, this is the offset in the
 308      .debug_types.dwo section.
 309      The value is zero until the actual value is known.
 310      Zero is otherwise not a valid section offset.  */
 311   sect_offset type_offset_in_section {};
 312
 313   /* Type units are grouped by their DW_AT_stmt_list entry so that they
 314      can share them.  This points to the containing symtab.  */
 315   struct type_unit_group *type_unit_group = nullptr;
 316
 317   /* Containing DWO unit.
 318      This field is valid iff per_cu.reading_dwo_directly.  */
 319   struct dwo_unit *dwo_unit = nullptr;
 320 };
 321
 322 using signatured_type_up = std::unique_ptr<signatured_type>;
 323
 324 /* Some DWARF data can be shared across objfiles who share the same BFD,
 325    this data is stored in this object.
 326
 327    Two dwarf2_per_objfile objects representing objfiles sharing the same BFD
 328    will point to the same instance of dwarf2_per_bfd, unless the BFD requires
 329    relocation.  */
 330
 331 struct dwarf2_per_bfd
 332 {
 333   /* Construct a dwarf2_per_bfd for OBFD.  NAMES points to the
 334      dwarf2 section names, or is NULL if the standard ELF names are
 335      used.  CAN_COPY is true for formats where symbol
 336      interposition is possible and so symbol values must follow copy
 337      relocation rules.  */
 338   dwarf2_per_bfd (bfd *obfd, const dwarf2_debug_sections *names, bool can_copy);
 339
 340   ~dwarf2_per_bfd ();
 341
 342   DISABLE_COPY_AND_ASSIGN (dwarf2_per_bfd);
 343
 344   /* Return the CU given its index.  */
 345   dwarf2_per_cu_data *get_cu (int index) const
 346   {
 347     return this->all_comp_units[index].get ();
 348   }
 349
 350   /* A convenience function to allocate a dwarf2_per_cu_data.  The
 351      returned object has its "index" field set properly.  The object
 352      is allocated on the dwarf2_per_bfd obstack.  */
 353   dwarf2_per_cu_data_up allocate_per_cu ();
 354
 355   /* A convenience function to allocate a signatured_type.  The
 356      returned object has its "index" field set properly.  The object
 357      is allocated on the dwarf2_per_bfd obstack.  */
 358   signatured_type_up allocate_signatured_type (ULONGEST signature);
 359
 360 private:
 361   /* This function is mapped across the sections and remembers the
 362      offset and size of each of the debugging sections we are
 363      interested in.  */
 364   void locate_sections (bfd *abfd, asection *sectp,
 365                         const dwarf2_debug_sections &names);
 366
 367 public:
 368   /* The corresponding BFD.  */
 369   bfd *obfd;
 370
 371   /* Objects that can be shared across objfiles are stored in this
 372      obstack or on the psymtab obstack, while objects that are
 373      objfile-specific are stored on the objfile obstack.  */
 374   auto_obstack obstack;
 375
 376   dwarf2_section_info info {};
 377   dwarf2_section_info abbrev {};
 378   dwarf2_section_info line {};
 379   dwarf2_section_info loc {};
 380   dwarf2_section_info loclists {};
 381   dwarf2_section_info macinfo {};
 382   dwarf2_section_info macro {};
 383   dwarf2_section_info str {};
 384   dwarf2_section_info str_offsets {};
 385   dwarf2_section_info line_str {};
 386   dwarf2_section_info ranges {};
 387   dwarf2_section_info rnglists {};
 388   dwarf2_section_info addr {};
 389   dwarf2_section_info frame {};
 390   dwarf2_section_info eh_frame {};
 391   dwarf2_section_info gdb_index {};
 392   dwarf2_section_info debug_names {};
 393   dwarf2_section_info debug_aranges {};
 394
 395   std::vector<dwarf2_section_info> types;
 396
 397   /* Table of all the compilation units.  This is used to locate
 398      the target compilation unit of a particular reference.  */
 399   std::vector<dwarf2_per_cu_data_up> all_comp_units;
 400
 401   /* Table of struct type_unit_group objects.
 402      The hash key is the DW_AT_stmt_list value.  */
 403   htab_up type_unit_groups;
 404
 405   /* A table mapping .debug_types signatures to its signatured_type entry.
 406      This is NULL if the .debug_types section hasn't been read in yet.  */
 407   htab_up signatured_types;
 408
 409   /* Type unit statistics, to see how well the scaling improvements
 410      are doing.  */
 411   struct tu_stats tu_stats {};
 412
 413   /* A table mapping DW_AT_dwo_name values to struct dwo_file objects.
 414      This is NULL if the table hasn't been allocated yet.  */
 415   htab_up dwo_files;
 416
 417   /* True if we've checked for whether there is a DWP file.  */
 418   bool dwp_checked = false;
 419
 420   /* The DWP file if there is one, or NULL.  */
 421   std::unique_ptr<struct dwp_file> dwp_file;
 422
 423   /* The shared '.dwz' file, if one exists.  This is used when the
 424      original data was compressed using 'dwz -m'.  */
 425   std::unique_ptr<struct dwz_file> dwz_file;
 426
 427   /* Whether copy relocations are supported by this object format.  */
 428   bool can_copy;
 429
 430   /* A flag indicating whether this objfile has a section loaded at a
 431      VMA of 0.  */
 432   bool has_section_at_zero = false;
 433
 434   /* True if we are using the mapped index,
 435      or we are faking it for OBJF_READNOW's sake.  */
 436   bool using_index = false;
 437
 438   /* The mapped index, or NULL if .gdb_index is missing or not being used.  */
 439   std::unique_ptr<mapped_index> index_table;
 440
 441   /* The mapped index, or NULL if .debug_names is missing or not being used.  */
 442   std::unique_ptr<mapped_debug_names> debug_names_table;
 443
 444   /* When using index_table, this keeps track of all quick_file_names entries.
 445      TUs typically share line table entries with a CU, so we maintain a
 446      separate table of all line table entries to support the sharing.
 447      Note that while there can be way more TUs than CUs, we've already
 448      sorted all the TUs into "type unit groups", grouped by their
 449      DW_AT_stmt_list value.  Therefore the only sharing done here is with a
 450      CU and its associated TU group if there is one.  */
 451   htab_up quick_file_names_table;
 452
 453   /* Set during partial symbol reading, to prevent queueing of full
 454      symbols.  */
 455   bool reading_partial_symbols = false;
 456
 457   /* The CUs we recently read.  */
 458   std::vector<dwarf2_per_cu_data *> just_read_cus;
 459
 460   /* If we loaded the index from an external file, this contains the
 461      resources associated to the open file, memory mapping, etc.  */
 462   std::unique_ptr<index_cache_resource> index_cache_res;
 463
 464   /* Mapping from abstract origin DIE to concrete DIEs that reference it as
 465      DW_AT_abstract_origin.  */
 466   std::unordered_map<sect_offset, std::vector<sect_offset>,
 467                      gdb::hash_enum<sect_offset>>
 468     abstract_to_concrete;
 469
 470   /* CUs that are queued to be read.  */
 471   gdb::optional<std::queue<dwarf2_queue_item>> queue;
 472
 473   /* We keep a separate reference to the partial symtabs, in case we
 474      are sharing them between objfiles.  This is only set after
 475      partial symbols have been read the first time.  */
 476   std::shared_ptr<psymtab_storage> partial_symtabs;
 477
 478   /* The address map that is used by the DWARF index code.  */
 479   struct addrmap *index_addrmap = nullptr;
 480 };
 481
 482 /* This is the per-objfile data associated with a type_unit_group.  */
 483
 484 struct type_unit_group_unshareable
 485 {
 486   /* The compunit symtab.
 487      Type units in a group needn't all be defined in the same source file,
 488      so we create an essentially anonymous symtab as the compunit symtab.  */
 489   struct compunit_symtab *compunit_symtab = nullptr;
 490
 491   /* The number of symtabs from the line header.
 492      The value here must match line_header.num_file_names.  */
 493   unsigned int num_symtabs = 0;
 494
 495   /* The symbol tables for this TU (obtained from the files listed in
 496      DW_AT_stmt_list).
 497      WARNING: The order of entries here must match the order of entries
 498      in the line header.  After the first TU using this type_unit_group, the
 499      line header for the subsequent TUs is recreated from this.  This is done
 500      because we need to use the same symtabs for each TU using the same
 501      DW_AT_stmt_list value.  Also note that symtabs may be repeated here,
 502      there's no guarantee the line header doesn't have duplicate entries.  */
 503   struct symtab **symtabs = nullptr;
 504 };
 505
 506 /* Collection of data recorded per objfile.
 507    This hangs off of dwarf2_objfile_data_key.
 508
 509    Some DWARF data cannot (currently) be shared across objfiles.  Such
 510    data is stored in this object.  */
 511
 512 struct dwarf2_per_objfile
 513 {
 514   dwarf2_per_objfile (struct objfile *objfile, dwarf2_per_bfd *per_bfd)
 515     : objfile (objfile), per_bfd (per_bfd)
 516   {}
 517
 518   ~dwarf2_per_objfile ();
 519
 520   /* Return pointer to string at .debug_line_str offset as read from BUF.
 521      BUF is assumed to be in a compilation unit described by CU_HEADER.
 522      Return *BYTES_READ_PTR count of bytes read from BUF.  */
 523   const char *read_line_string (const gdb_byte *buf,
 524                                 const struct comp_unit_head *cu_header,
 525                                 unsigned int *bytes_read_ptr);
 526
 527   /* Return pointer to string at .debug_line_str offset as read from BUF.
 528      The offset_size is OFFSET_SIZE.  */
 529   const char *read_line_string (const gdb_byte *buf,
 530                                 unsigned int offset_size);
 531
 532   /* Return true if the symtab corresponding to PER_CU has been set,
 533      false otherwise.  */
 534   bool symtab_set_p (const dwarf2_per_cu_data *per_cu) const;
 535
 536   /* Return the compunit_symtab associated to PER_CU, if it has been created.  */
 537   compunit_symtab *get_symtab (const dwarf2_per_cu_data *per_cu) const;
 538
 539   /* Set the compunit_symtab associated to PER_CU.  */
 540   void set_symtab (const dwarf2_per_cu_data *per_cu, compunit_symtab *symtab);
 541
 542   /* Get the type_unit_group_unshareable corresponding to TU_GROUP.  If one
 543      does not exist, create it.  */
 544   type_unit_group_unshareable *get_type_unit_group_unshareable
 545     (type_unit_group *tu_group);
 546
 547   struct type *get_type_for_signatured_type (signatured_type *sig_type) const;
 548
 549   void set_type_for_signatured_type (signatured_type *sig_type,
 550                                      struct type *type);
 551
 552   /* Get the dwarf2_cu matching PER_CU for this objfile.  */
 553   dwarf2_cu *get_cu (dwarf2_per_cu_data *per_cu);
 554
 555   /* Set the dwarf2_cu matching PER_CU for this objfile.  */
 556   void set_cu (dwarf2_per_cu_data *per_cu, dwarf2_cu *cu);
 557
 558   /* Remove/free the dwarf2_cu matching PER_CU for this objfile.  */
 559   void remove_cu (dwarf2_per_cu_data *per_cu);
 560
 561   /* Free all cached compilation units.  */
 562   void remove_all_cus ();
 563
 564   /* Increase the age counter on each CU compilation unit and free
 565      any that are too old.  */
 566   void age_comp_units ();
 567
 568   /* Back link.  */
 569   struct objfile *objfile;
 570
 571   /* Pointer to the data that is (possibly) shared between this objfile and
 572      other objfiles backed by the same BFD.  */
 573   struct dwarf2_per_bfd *per_bfd;
 574
 575   /* Table mapping type DIEs to their struct type *.
 576      This is nullptr if not allocated yet.
 577      The mapping is done via (CU/TU + DIE offset) -> type.  */
 578   htab_up die_type_hash;
 579
 580   /* Table containing line_header indexed by offset and offset_in_dwz.  */
 581   htab_up line_header_hash;
 582
 583   /* The CU containing the m_builder in scope.  */
 584   dwarf2_cu *sym_cu = nullptr;
 585
 586 private:
 587   /* Hold the corresponding compunit_symtab for each CU or TU.  This
 588      is indexed by dwarf2_per_cu_data::index.  A NULL value means
 589      that the CU/TU has not been expanded yet.  */
 590   std::vector<compunit_symtab *> m_symtabs;
 591
 592   /* Map from a type unit group to the corresponding unshared
 593      structure.  */
 594   typedef std::unique_ptr<type_unit_group_unshareable>
 595     type_unit_group_unshareable_up;
 596
 597   std::unordered_map<type_unit_group *, type_unit_group_unshareable_up>
 598     m_type_units;
 599
 600   /* Map from signatured types to the corresponding struct type.  */
 601   std::unordered_map<signatured_type *, struct type *> m_type_map;
 602
 603   /* Map from the objfile-independent dwarf2_per_cu_data instances to the
 604      corresponding objfile-dependent dwarf2_cu instances.  */
 605   std::unordered_map<dwarf2_per_cu_data *, dwarf2_cu *> m_dwarf2_cus;
 606 };
 607
 608 /* Get the dwarf2_per_objfile associated to OBJFILE.  */
 609
 610 dwarf2_per_objfile *get_dwarf2_per_objfile (struct objfile *objfile);
 611
 612 /* A partial symtab specialized for DWARF.  */
 613 struct dwarf2_psymtab : public partial_symtab
 614 {
 615   dwarf2_psymtab (const char *filename,
 616                   psymtab_storage *partial_symtabs,
 617                   objfile_per_bfd_storage *objfile_per_bfd,
 618                   dwarf2_per_cu_data *per_cu)
 619     : partial_symtab (filename, partial_symtabs, objfile_per_bfd, 0),
 620       per_cu_data (per_cu)
 621   {
 622   }
 623
 624   void read_symtab (struct objfile *) override;
 625   void expand_psymtab (struct objfile *) override;
 626   bool readin_p (struct objfile *) const override;
 627   compunit_symtab *get_compunit_symtab (struct objfile *) const override;
 628
 629   struct dwarf2_per_cu_data *per_cu_data;
 630 };
 631
 632 /* Return the type of the DIE at DIE_OFFSET in the CU named by
 633    PER_CU.  */
 634
 635 struct type *dwarf2_get_die_type (cu_offset die_offset,
 636                                   dwarf2_per_cu_data *per_cu,
 637                                   dwarf2_per_objfile *per_objfile);
 638
 639 /* Given an index in .debug_addr, fetch the value.
 640    NOTE: This can be called during dwarf expression evaluation,
 641    long after the debug information has been read, and thus per_cu->cu
 642    may no longer exist.  */
 643
 644 CORE_ADDR dwarf2_read_addr_index (dwarf2_per_cu_data *per_cu,
 645                                   dwarf2_per_objfile *per_objfile,
 646                                   unsigned int addr_index);
 647
 648 /* Return DWARF block referenced by DW_AT_location of DIE at SECT_OFF at PER_CU.
 649    Returned value is intended for DW_OP_call*.  Returned
 650    dwarf2_locexpr_baton->data has lifetime of
 651    PER_CU->DWARF2_PER_OBJFILE->OBJFILE.  */
 652
 653 struct dwarf2_locexpr_baton dwarf2_fetch_die_loc_sect_off
 654   (sect_offset sect_off, dwarf2_per_cu_data *per_cu,
 655    dwarf2_per_objfile *per_objfile,
 656    gdb::function_view<CORE_ADDR ()> get_frame_pc,
 657    bool resolve_abstract_p = false);
 658
 659 /* Like dwarf2_fetch_die_loc_sect_off, but take a CU
 660    offset.  */
 661
 662 struct dwarf2_locexpr_baton dwarf2_fetch_die_loc_cu_off
 663   (cu_offset offset_in_cu, dwarf2_per_cu_data *per_cu,
 664    dwarf2_per_objfile *per_objfile,
 665    gdb::function_view<CORE_ADDR ()> get_frame_pc);
 666
 667 /* If the DIE at SECT_OFF in PER_CU has a DW_AT_const_value, return a
 668    pointer to the constant bytes and set LEN to the length of the
 669    data.  If memory is needed, allocate it on OBSTACK.  If the DIE
 670    does not have a DW_AT_const_value, return NULL.  */
 671
 672 extern const gdb_byte *dwarf2_fetch_constant_bytes
 673   (sect_offset sect_off, dwarf2_per_cu_data *per_cu,
 674    dwarf2_per_objfile *per_objfile, obstack *obstack,
 675    LONGEST *len);
 676
 677 /* Return the type of the die at SECT_OFF in PER_CU.  Return NULL if no
 678    valid type for this die is found.  If VAR_NAME is non-null, and if
 679    the DIE in question is a variable declaration (definitions are
 680    excluded), then *VAR_NAME is set to the variable's name.  */
 681
 682 struct type *dwarf2_fetch_die_type_sect_off
 683   (sect_offset sect_off, dwarf2_per_cu_data *per_cu,
 684    dwarf2_per_objfile *per_objfile,
 685    const char **var_name = nullptr);
 686
 687 /* When non-zero, dump line number entries as they are read in.  */
 688 extern unsigned int dwarf_line_debug;
 689
 690 /* Dwarf2 sections that can be accessed by dwarf2_get_section_info.  */
 691 enum dwarf2_section_enum {
 692   DWARF2_DEBUG_FRAME,
 693   DWARF2_EH_FRAME
 694 };
 695
 696 extern void dwarf2_get_section_info (struct objfile *,
 697                                      enum dwarf2_section_enum,
 698                                      asection **, const gdb_byte **,
 699                                      bfd_size_type *);
 700
 701 #endif /* DWARF2READ_H */