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
 280 /* Entry in the signatured_types hash table.  */
 281
 282 struct signatured_type : public dwarf2_per_cu_data
 283 {
 284   signatured_type (ULONGEST signature)
 285     : signature (signature)
 286   {}
 287
 288   /* The type's signature.  */
 289   ULONGEST signature;
 290
 291   /* Offset in the TU of the type's DIE, as read from the TU header.
 292      If this TU is a DWO stub and the definition lives in a DWO file
 293      (specified by DW_AT_GNU_dwo_name), this value is unusable.  */
 294   cu_offset type_offset_in_tu {};
 295
 296   /* Offset in the section of the type's DIE.
 297      If the definition lives in a DWO file, this is the offset in the
 298      .debug_types.dwo section.
 299      The value is zero until the actual value is known.
 300      Zero is otherwise not a valid section offset.  */
 301   sect_offset type_offset_in_section {};
 302
 303   /* Type units are grouped by their DW_AT_stmt_list entry so that they
 304      can share them.  This points to the containing symtab.  */
 305   struct type_unit_group *type_unit_group = nullptr;
 306
 307   /* Containing DWO unit.
 308      This field is valid iff per_cu.reading_dwo_directly.  */
 309   struct dwo_unit *dwo_unit = nullptr;
 310 };
 311
 312 using signatured_type_up = std::unique_ptr<signatured_type>;
 313
 314 /* Some DWARF data can be shared across objfiles who share the same BFD,
 315    this data is stored in this object.
 316
 317    Two dwarf2_per_objfile objects representing objfiles sharing the same BFD
 318    will point to the same instance of dwarf2_per_bfd, unless the BFD requires
 319    relocation.  */
 320
 321 struct dwarf2_per_bfd
 322 {
 323   /* Construct a dwarf2_per_bfd for OBFD.  NAMES points to the
 324      dwarf2 section names, or is NULL if the standard ELF names are
 325      used.  CAN_COPY is true for formats where symbol
 326      interposition is possible and so symbol values must follow copy
 327      relocation rules.  */
 328   dwarf2_per_bfd (bfd *obfd, const dwarf2_debug_sections *names, bool can_copy);
 329
 330   ~dwarf2_per_bfd ();
 331
 332   DISABLE_COPY_AND_ASSIGN (dwarf2_per_bfd);
 333
 334   /* Return the CU given its index.  */
 335   dwarf2_per_cu_data *get_cu (int index) const
 336   {
 337     return this->all_comp_units[index].get ();
 338   }
 339
 340   /* A convenience function to allocate a dwarf2_per_cu_data.  The
 341      returned object has its "index" field set properly.  The object
 342      is allocated on the dwarf2_per_bfd obstack.  */
 343   dwarf2_per_cu_data_up allocate_per_cu ();
 344
 345   /* A convenience function to allocate a signatured_type.  The
 346      returned object has its "index" field set properly.  The object
 347      is allocated on the dwarf2_per_bfd obstack.  */
 348   signatured_type_up allocate_signatured_type (ULONGEST signature);
 349
 350 private:
 351   /* This function is mapped across the sections and remembers the
 352      offset and size of each of the debugging sections we are
 353      interested in.  */
 354   void locate_sections (bfd *abfd, asection *sectp,
 355                         const dwarf2_debug_sections &names);
 356
 357 public:
 358   /* The corresponding BFD.  */
 359   bfd *obfd;
 360
 361   /* Objects that can be shared across objfiles are stored in this
 362      obstack or on the psymtab obstack, while objects that are
 363      objfile-specific are stored on the objfile obstack.  */
 364   auto_obstack obstack;
 365
 366   dwarf2_section_info info {};
 367   dwarf2_section_info abbrev {};
 368   dwarf2_section_info line {};
 369   dwarf2_section_info loc {};
 370   dwarf2_section_info loclists {};
 371   dwarf2_section_info macinfo {};
 372   dwarf2_section_info macro {};
 373   dwarf2_section_info str {};
 374   dwarf2_section_info str_offsets {};
 375   dwarf2_section_info line_str {};
 376   dwarf2_section_info ranges {};
 377   dwarf2_section_info rnglists {};
 378   dwarf2_section_info addr {};
 379   dwarf2_section_info frame {};
 380   dwarf2_section_info eh_frame {};
 381   dwarf2_section_info gdb_index {};
 382   dwarf2_section_info debug_names {};
 383   dwarf2_section_info debug_aranges {};
 384
 385   std::vector<dwarf2_section_info> types;
 386
 387   /* Table of all the compilation units.  This is used to locate
 388      the target compilation unit of a particular reference.  */
 389   std::vector<dwarf2_per_cu_data_up> all_comp_units;
 390
 391   /* Table of struct type_unit_group objects.
 392      The hash key is the DW_AT_stmt_list value.  */
 393   htab_up type_unit_groups;
 394
 395   /* A table mapping .debug_types signatures to its signatured_type entry.
 396      This is NULL if the .debug_types section hasn't been read in yet.  */
 397   htab_up signatured_types;
 398
 399   /* Type unit statistics, to see how well the scaling improvements
 400      are doing.  */
 401   struct tu_stats tu_stats {};
 402
 403   /* A table mapping DW_AT_dwo_name values to struct dwo_file objects.
 404      This is NULL if the table hasn't been allocated yet.  */
 405   htab_up dwo_files;
 406
 407   /* True if we've checked for whether there is a DWP file.  */
 408   bool dwp_checked = false;
 409
 410   /* The DWP file if there is one, or NULL.  */
 411   std::unique_ptr<struct dwp_file> dwp_file;
 412
 413   /* The shared '.dwz' file, if one exists.  This is used when the
 414      original data was compressed using 'dwz -m'.  */
 415   std::unique_ptr<struct dwz_file> dwz_file;
 416
 417   /* Whether copy relocations are supported by this object format.  */
 418   bool can_copy;
 419
 420   /* A flag indicating whether this objfile has a section loaded at a
 421      VMA of 0.  */
 422   bool has_section_at_zero = false;
 423
 424   /* True if we are using the mapped index,
 425      or we are faking it for OBJF_READNOW's sake.  */
 426   bool using_index = false;
 427
 428   /* The mapped index, or NULL if .gdb_index is missing or not being used.  */
 429   std::unique_ptr<mapped_index> index_table;
 430
 431   /* The mapped index, or NULL if .debug_names is missing or not being used.  */
 432   std::unique_ptr<mapped_debug_names> debug_names_table;
 433
 434   /* When using index_table, this keeps track of all quick_file_names entries.
 435      TUs typically share line table entries with a CU, so we maintain a
 436      separate table of all line table entries to support the sharing.
 437      Note that while there can be way more TUs than CUs, we've already
 438      sorted all the TUs into "type unit groups", grouped by their
 439      DW_AT_stmt_list value.  Therefore the only sharing done here is with a
 440      CU and its associated TU group if there is one.  */
 441   htab_up quick_file_names_table;
 442
 443   /* Set during partial symbol reading, to prevent queueing of full
 444      symbols.  */
 445   bool reading_partial_symbols = false;
 446
 447   /* The CUs we recently read.  */
 448   std::vector<dwarf2_per_cu_data *> just_read_cus;
 449
 450   /* If we loaded the index from an external file, this contains the
 451      resources associated to the open file, memory mapping, etc.  */
 452   std::unique_ptr<index_cache_resource> index_cache_res;
 453
 454   /* Mapping from abstract origin DIE to concrete DIEs that reference it as
 455      DW_AT_abstract_origin.  */
 456   std::unordered_map<sect_offset, std::vector<sect_offset>,
 457                      gdb::hash_enum<sect_offset>>
 458     abstract_to_concrete;
 459
 460   /* CUs that are queued to be read.  */
 461   gdb::optional<std::queue<dwarf2_queue_item>> queue;
 462
 463   /* We keep a separate reference to the partial symtabs, in case we
 464      are sharing them between objfiles.  This is only set after
 465      partial symbols have been read the first time.  */
 466   std::shared_ptr<psymtab_storage> partial_symtabs;
 467
 468   /* The address map that is used by the DWARF index code.  */
 469   struct addrmap *index_addrmap = nullptr;
 470 };
 471
 472 /* This is the per-objfile data associated with a type_unit_group.  */
 473
 474 struct type_unit_group_unshareable
 475 {
 476   /* The compunit symtab.
 477      Type units in a group needn't all be defined in the same source file,
 478      so we create an essentially anonymous symtab as the compunit symtab.  */
 479   struct compunit_symtab *compunit_symtab = nullptr;
 480
 481   /* The number of symtabs from the line header.
 482      The value here must match line_header.num_file_names.  */
 483   unsigned int num_symtabs = 0;
 484
 485   /* The symbol tables for this TU (obtained from the files listed in
 486      DW_AT_stmt_list).
 487      WARNING: The order of entries here must match the order of entries
 488      in the line header.  After the first TU using this type_unit_group, the
 489      line header for the subsequent TUs is recreated from this.  This is done
 490      because we need to use the same symtabs for each TU using the same
 491      DW_AT_stmt_list value.  Also note that symtabs may be repeated here,
 492      there's no guarantee the line header doesn't have duplicate entries.  */
 493   struct symtab **symtabs = nullptr;
 494 };
 495
 496 /* Collection of data recorded per objfile.
 497    This hangs off of dwarf2_objfile_data_key.
 498
 499    Some DWARF data cannot (currently) be shared across objfiles.  Such
 500    data is stored in this object.  */
 501
 502 struct dwarf2_per_objfile
 503 {
 504   dwarf2_per_objfile (struct objfile *objfile, dwarf2_per_bfd *per_bfd)
 505     : objfile (objfile), per_bfd (per_bfd)
 506   {}
 507
 508   ~dwarf2_per_objfile ();
 509
 510   /* Return pointer to string at .debug_line_str offset as read from BUF.
 511      BUF is assumed to be in a compilation unit described by CU_HEADER.
 512      Return *BYTES_READ_PTR count of bytes read from BUF.  */
 513   const char *read_line_string (const gdb_byte *buf,
 514                                 const struct comp_unit_head *cu_header,
 515                                 unsigned int *bytes_read_ptr);
 516
 517   /* Resize the M_SYMTABS vector to the needed size (the number of partial
 518      symtabs allocated by the per-bfd).  */
 519   void resize_symtabs ()
 520   {
 521     /* The symtabs vector should only grow, not shrink.  */
 522     gdb_assert (per_bfd->all_comp_units.size () >= m_symtabs.size ());
 523
 524     m_symtabs.resize (per_bfd->all_comp_units.size ());
 525   }
 526
 527   /* Return true if the symtab corresponding to PER_CU has been set,
 528      false otherwise.  */
 529   bool symtab_set_p (const dwarf2_per_cu_data *per_cu) const;
 530
 531   /* Return the compunit_symtab associated to PER_CU, if it has been created.  */
 532   compunit_symtab *get_symtab (const dwarf2_per_cu_data *per_cu) const;
 533
 534   /* Set the compunit_symtab associated to PER_CU.  */
 535   void set_symtab (const dwarf2_per_cu_data *per_cu, compunit_symtab *symtab);
 536
 537   /* Get the type_unit_group_unshareable corresponding to TU_GROUP.  If one
 538      does not exist, create it.  */
 539   type_unit_group_unshareable *get_type_unit_group_unshareable
 540     (type_unit_group *tu_group);
 541
 542   struct type *get_type_for_signatured_type (signatured_type *sig_type) const;
 543
 544   void set_type_for_signatured_type (signatured_type *sig_type,
 545                                      struct type *type);
 546
 547   /* Find an integer type SIZE_IN_BYTES bytes in size and return it.
 548      UNSIGNED_P controls if the integer is unsigned or not.  */
 549   struct type *int_type (int size_in_bytes, bool unsigned_p) const;
 550
 551   /* Get the dwarf2_cu matching PER_CU for this objfile.  */
 552   dwarf2_cu *get_cu (dwarf2_per_cu_data *per_cu);
 553
 554   /* Set the dwarf2_cu matching PER_CU for this objfile.  */
 555   void set_cu (dwarf2_per_cu_data *per_cu, dwarf2_cu *cu);
 556
 557   /* Remove/free the dwarf2_cu matching PER_CU for this objfile.  */
 558   void remove_cu (dwarf2_per_cu_data *per_cu);
 559
 560   /* Free all cached compilation units.  */
 561   void remove_all_cus ();
 562
 563   /* Increase the age counter on each CU compilation unit and free
 564      any that are too old.  */
 565   void age_comp_units ();
 566
 567   /* Back link.  */
 568   struct objfile *objfile;
 569
 570   /* Pointer to the data that is (possibly) shared between this objfile and
 571      other objfiles backed by the same BFD.  */
 572   struct dwarf2_per_bfd *per_bfd;
 573
 574   /* Table mapping type DIEs to their struct type *.
 575      This is nullptr if not allocated yet.
 576      The mapping is done via (CU/TU + DIE offset) -> type.  */
 577   htab_up die_type_hash;
 578
 579   /* Table containing line_header indexed by offset and offset_in_dwz.  */
 580   htab_up line_header_hash;
 581
 582   /* The CU containing the m_builder in scope.  */
 583   dwarf2_cu *sym_cu = nullptr;
 584
 585 private:
 586   /* Hold the corresponding compunit_symtab for each CU or TU.  This
 587      is indexed by dwarf2_per_cu_data::index.  A NULL value means
 588      that the CU/TU has not been expanded yet.  */
 589   std::vector<compunit_symtab *> m_symtabs;
 590
 591   /* Map from a type unit group to the corresponding unshared
 592      structure.  */
 593   typedef std::unique_ptr<type_unit_group_unshareable>
 594     type_unit_group_unshareable_up;
 595
 596   std::unordered_map<type_unit_group *, type_unit_group_unshareable_up>
 597     m_type_units;
 598
 599   /* Map from signatured types to the corresponding struct type.  */
 600   std::unordered_map<signatured_type *, struct type *> m_type_map;
 601
 602   /* Map from the objfile-independent dwarf2_per_cu_data instances to the
 603      corresponding objfile-dependent dwarf2_cu instances.  */
 604   std::unordered_map<dwarf2_per_cu_data *, dwarf2_cu *> m_dwarf2_cus;
 605 };
 606
 607 /* Get the dwarf2_per_objfile associated to OBJFILE.  */
 608
 609 dwarf2_per_objfile *get_dwarf2_per_objfile (struct objfile *objfile);
 610
 611 /* A partial symtab specialized for DWARF.  */
 612 struct dwarf2_psymtab : public partial_symtab
 613 {
 614   dwarf2_psymtab (const char *filename,
 615                   psymtab_storage *partial_symtabs,
 616                   objfile_per_bfd_storage *objfile_per_bfd,
 617                   dwarf2_per_cu_data *per_cu)
 618     : partial_symtab (filename, partial_symtabs, objfile_per_bfd, 0),
 619       per_cu_data (per_cu)
 620   {
 621   }
 622
 623   void read_symtab (struct objfile *) override;
 624   void expand_psymtab (struct objfile *) override;
 625   bool readin_p (struct objfile *) const override;
 626   compunit_symtab *get_compunit_symtab (struct objfile *) const override;
 627
 628   struct dwarf2_per_cu_data *per_cu_data;
 629 };
 630
 631 /* Return the type of the DIE at DIE_OFFSET in the CU named by
 632    PER_CU.  */
 633
 634 struct type *dwarf2_get_die_type (cu_offset die_offset,
 635                                   dwarf2_per_cu_data *per_cu,
 636                                   dwarf2_per_objfile *per_objfile);
 637
 638 /* Given an index in .debug_addr, fetch the value.
 639    NOTE: This can be called during dwarf expression evaluation,
 640    long after the debug information has been read, and thus per_cu->cu
 641    may no longer exist.  */
 642
 643 CORE_ADDR dwarf2_read_addr_index (dwarf2_per_cu_data *per_cu,
 644                                   dwarf2_per_objfile *per_objfile,
 645                                   unsigned int addr_index);
 646
 647 /* Return DWARF block referenced by DW_AT_location of DIE at SECT_OFF at PER_CU.
 648    Returned value is intended for DW_OP_call*.  Returned
 649    dwarf2_locexpr_baton->data has lifetime of
 650    PER_CU->DWARF2_PER_OBJFILE->OBJFILE.  */
 651
 652 struct dwarf2_locexpr_baton dwarf2_fetch_die_loc_sect_off
 653   (sect_offset sect_off, dwarf2_per_cu_data *per_cu,
 654    dwarf2_per_objfile *per_objfile,
 655    gdb::function_view<CORE_ADDR ()> get_frame_pc,
 656    bool resolve_abstract_p = false);
 657
 658 /* Like dwarf2_fetch_die_loc_sect_off, but take a CU
 659    offset.  */
 660
 661 struct dwarf2_locexpr_baton dwarf2_fetch_die_loc_cu_off
 662   (cu_offset offset_in_cu, dwarf2_per_cu_data *per_cu,
 663    dwarf2_per_objfile *per_objfile,
 664    gdb::function_view<CORE_ADDR ()> get_frame_pc);
 665
 666 /* If the DIE at SECT_OFF in PER_CU has a DW_AT_const_value, return a
 667    pointer to the constant bytes and set LEN to the length of the
 668    data.  If memory is needed, allocate it on OBSTACK.  If the DIE
 669    does not have a DW_AT_const_value, return NULL.  */
 670
 671 extern const gdb_byte *dwarf2_fetch_constant_bytes
 672   (sect_offset sect_off, dwarf2_per_cu_data *per_cu,
 673    dwarf2_per_objfile *per_objfile, obstack *obstack,
 674    LONGEST *len);
 675
 676 /* Return the type of the die at SECT_OFF in PER_CU.  Return NULL if no
 677    valid type for this die is found.  If VAR_NAME is non-null, and if
 678    the DIE in question is a variable declaration (definitions are
 679    excluded), then *VAR_NAME is set to the variable's name.  */
 680
 681 struct type *dwarf2_fetch_die_type_sect_off
 682   (sect_offset sect_off, dwarf2_per_cu_data *per_cu,
 683    dwarf2_per_objfile *per_objfile,
 684    const char **var_name = nullptr);
 685
 686 /* When non-zero, dump line number entries as they are read in.  */
 687 extern unsigned int dwarf_line_debug;
 688
 689 /* Dwarf2 sections that can be accessed by dwarf2_get_section_info.  */
 690 enum dwarf2_section_enum {
 691   DWARF2_DEBUG_FRAME,
 692   DWARF2_EH_FRAME
 693 };
 694
 695 extern void dwarf2_get_section_info (struct objfile *,
 696                                      enum dwarf2_section_enum,
 697                                      asection **, const gdb_byte **,
 698                                      bfd_size_type *);
 699
 700 #endif /* DWARF2READ_H */