gdb/dwarf2/read.h

   1 /* DWARF 2 debugging format support for GDB.
   2
   3    Copyright (C) 1994-2020 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/index-cache.h"
  26 #include "dwarf2/section.h"
  27 #include "filename-seen-cache.h"
  28 #include "gdb_obstack.h"
  29 #include "gdbsupport/hash_enum.h"
  30 #include "psympriv.h"
  31
  32 /* Hold 'maintenance (set|show) dwarf' commands.  */
  33 extern struct cmd_list_element *set_dwarf_cmdlist;
  34 extern struct cmd_list_element *show_dwarf_cmdlist;
  35
  36 struct tu_stats
  37 {
  38   int nr_uniq_abbrev_tables;
  39   int nr_symtabs;
  40   int nr_symtab_sharers;
  41   int nr_stmt_less_type_units;
  42   int nr_all_type_units_reallocs;
  43 };
  44
  45 struct dwarf2_debug_sections;
  46 struct dwarf2_per_cu_data;
  47 struct mapped_index;
  48 struct mapped_debug_names;
  49 struct signatured_type;
  50 struct type_unit_group;
  51
  52 /* One item on the queue of compilation units to read in full symbols
  53    for.  */
  54 struct dwarf2_queue_item
  55 {
  56   dwarf2_queue_item (dwarf2_per_cu_data *cu, dwarf2_per_objfile *per_objfile,
  57                      enum language lang)
  58     : per_cu (cu),
  59       per_objfile (per_objfile),
  60       pretend_language (lang)
  61   {
  62   }
  63
  64   ~dwarf2_queue_item ();
  65
  66   DISABLE_COPY_AND_ASSIGN (dwarf2_queue_item);
  67
  68   dwarf2_per_cu_data *per_cu;
  69   dwarf2_per_objfile *per_objfile;
  70   enum language pretend_language;
  71 };
  72
  73 /* Some DWARF data can be shared across objfiles who share the same BFD,
  74    this data is stored in this object.
  75
  76    Two dwarf2_per_objfile objects representing objfiles sharing the same BFD
  77    will point to the same instance of dwarf2_per_bfd, unless the BFD requires
  78    relocation.  */
  79
  80 struct dwarf2_per_bfd
  81 {
  82   /* Construct a dwarf2_per_bfd for OBFD.  NAMES points to the
  83      dwarf2 section names, or is NULL if the standard ELF names are
  84      used.  CAN_COPY is true for formats where symbol
  85      interposition is possible and so symbol values must follow copy
  86      relocation rules.  */
  87   dwarf2_per_bfd (bfd *obfd, const dwarf2_debug_sections *names, bool can_copy);
  88
  89   ~dwarf2_per_bfd ();
  90
  91   DISABLE_COPY_AND_ASSIGN (dwarf2_per_bfd);
  92
  93   /* Return the CU/TU given its index.
  94
  95      This is intended for loops like:
  96
  97      for (i = 0; i < (dwarf2_per_bfd->n_comp_units
  98                       + dwarf2_per_bfd->n_type_units); ++i)
  99        {
 100          dwarf2_per_cu_data *per_cu = dwarf2_per_bfd->get_cutu (i);
 101
 102          ...;
 103        }
 104   */
 105   dwarf2_per_cu_data *get_cutu (int index);
 106
 107   /* Return the CU given its index.
 108      This differs from get_cutu in that it's for when you know INDEX refers to a
 109      CU.  */
 110   dwarf2_per_cu_data *get_cu (int index);
 111
 112   /* Return the TU given its index.
 113      This differs from get_cutu in that it's for when you know INDEX refers to a
 114      TU.  */
 115   signatured_type *get_tu (int index);
 116
 117   /* Free all cached compilation units.  */
 118   void free_cached_comp_units ();
 119
 120   /* A convenience function to allocate a dwarf2_per_cu_data.  The
 121      returned object has its "index" field set properly.  The object
 122      is allocated on the dwarf2_per_bfd obstack.  */
 123   dwarf2_per_cu_data *allocate_per_cu ();
 124
 125   /* A convenience function to allocate a signatured_type.  The
 126      returned object has its "index" field set properly.  The object
 127      is allocated on the dwarf2_per_bfd obstack.  */
 128   signatured_type *allocate_signatured_type ();
 129
 130   /* Return the number of partial symtabs allocated with allocate_per_cu
 131      and allocate_signatured_type so far.  */
 132   int num_psymtabs () const
 133   { return m_num_psymtabs; }
 134
 135 private:
 136   /* This function is mapped across the sections and remembers the
 137      offset and size of each of the debugging sections we are
 138      interested in.  */
 139   void locate_sections (bfd *abfd, asection *sectp,
 140                         const dwarf2_debug_sections &names);
 141
 142 public:
 143   /* The corresponding BFD.  */
 144   bfd *obfd;
 145
 146   /* Objects that can be shared across objfiles are stored in this
 147      obstack or on the psymtab obstack, while objects that are
 148      objfile-specific are stored on the objfile obstack.  */
 149   auto_obstack obstack;
 150
 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 str_offsets {};
 160   dwarf2_section_info line_str {};
 161   dwarf2_section_info ranges {};
 162   dwarf2_section_info rnglists {};
 163   dwarf2_section_info addr {};
 164   dwarf2_section_info frame {};
 165   dwarf2_section_info eh_frame {};
 166   dwarf2_section_info gdb_index {};
 167   dwarf2_section_info debug_names {};
 168   dwarf2_section_info debug_aranges {};
 169
 170   std::vector<dwarf2_section_info> types;
 171
 172   /* Table of all the compilation units.  This is used to locate
 173      the target compilation unit of a particular reference.  */
 174   std::vector<dwarf2_per_cu_data *> all_comp_units;
 175
 176   /* The .debug_types-related CUs (TUs).  */
 177   std::vector<signatured_type *> all_type_units;
 178
 179   /* Table of struct type_unit_group objects.
 180      The hash key is the DW_AT_stmt_list value.  */
 181   htab_up type_unit_groups;
 182
 183   /* A table mapping .debug_types signatures to its signatured_type entry.
 184      This is NULL if the .debug_types section hasn't been read in yet.  */
 185   htab_up signatured_types;
 186
 187   /* Type unit statistics, to see how well the scaling improvements
 188      are doing.  */
 189   struct tu_stats tu_stats {};
 190
 191   /* A chain of compilation units that are currently read in, so that
 192      they can be freed later.  */
 193   dwarf2_per_cu_data *read_in_chain = NULL;
 194
 195   /* A table mapping DW_AT_dwo_name values to struct dwo_file objects.
 196      This is NULL if the table hasn't been allocated yet.  */
 197   htab_up dwo_files;
 198
 199   /* True if we've checked for whether there is a DWP file.  */
 200   bool dwp_checked = false;
 201
 202   /* The DWP file if there is one, or NULL.  */
 203   std::unique_ptr<struct dwp_file> dwp_file;
 204
 205   /* The shared '.dwz' file, if one exists.  This is used when the
 206      original data was compressed using 'dwz -m'.  */
 207   std::unique_ptr<struct dwz_file> dwz_file;
 208
 209   /* Whether copy relocations are supported by this object format.  */
 210   bool can_copy;
 211
 212   /* A flag indicating whether this objfile has a section loaded at a
 213      VMA of 0.  */
 214   bool has_section_at_zero = false;
 215
 216   /* True if we are using the mapped index,
 217      or we are faking it for OBJF_READNOW's sake.  */
 218   bool using_index = false;
 219
 220   /* The mapped index, or NULL if .gdb_index is missing or not being used.  */
 221   std::unique_ptr<mapped_index> index_table;
 222
 223   /* The mapped index, or NULL if .debug_names is missing or not being used.  */
 224   std::unique_ptr<mapped_debug_names> debug_names_table;
 225
 226   /* When using index_table, this keeps track of all quick_file_names entries.
 227      TUs typically share line table entries with a CU, so we maintain a
 228      separate table of all line table entries to support the sharing.
 229      Note that while there can be way more TUs than CUs, we've already
 230      sorted all the TUs into "type unit groups", grouped by their
 231      DW_AT_stmt_list value.  Therefore the only sharing done here is with a
 232      CU and its associated TU group if there is one.  */
 233   htab_up quick_file_names_table;
 234
 235   /* Set during partial symbol reading, to prevent queueing of full
 236      symbols.  */
 237   bool reading_partial_symbols = false;
 238
 239   /* The CUs we recently read.  */
 240   std::vector<dwarf2_per_cu_data *> just_read_cus;
 241
 242   /* Table containing line_header indexed by offset and offset_in_dwz.  */
 243   htab_up line_header_hash;
 244
 245   /* Table containing all filenames.  This is an optional because the
 246      table is lazily constructed on first access.  */
 247   gdb::optional<filename_seen_cache> filenames_cache;
 248
 249   /* If we loaded the index from an external file, this contains the
 250      resources associated to the open file, memory mapping, etc.  */
 251   std::unique_ptr<index_cache_resource> index_cache_res;
 252
 253   /* Mapping from abstract origin DIE to concrete DIEs that reference it as
 254      DW_AT_abstract_origin.  */
 255   std::unordered_map<sect_offset, std::vector<sect_offset>,
 256                      gdb::hash_enum<sect_offset>>
 257     abstract_to_concrete;
 258
 259   /* CUs that are queued to be read.  */
 260   std::queue<dwarf2_queue_item> queue;
 261
 262 private:
 263
 264   /* The total number of per_cu and signatured_type objects that have
 265      been created so far for this reader.  */
 266   size_t m_num_psymtabs = 0;
 267 };
 268
 269 /* This is the per-objfile data associated with a type_unit_group.  */
 270
 271 struct type_unit_group_unshareable
 272 {
 273   /* The compunit symtab.
 274      Type units in a group needn't all be defined in the same source file,
 275      so we create an essentially anonymous symtab as the compunit symtab.  */
 276   struct compunit_symtab *compunit_symtab = nullptr;
 277
 278   /* The number of symtabs from the line header.
 279      The value here must match line_header.num_file_names.  */
 280   unsigned int num_symtabs = 0;
 281
 282   /* The symbol tables for this TU (obtained from the files listed in
 283      DW_AT_stmt_list).
 284      WARNING: The order of entries here must match the order of entries
 285      in the line header.  After the first TU using this type_unit_group, the
 286      line header for the subsequent TUs is recreated from this.  This is done
 287      because we need to use the same symtabs for each TU using the same
 288      DW_AT_stmt_list value.  Also note that symtabs may be repeated here,
 289      there's no guarantee the line header doesn't have duplicate entries.  */
 290   struct symtab **symtabs = nullptr;
 291 };
 292
 293 /* Collection of data recorded per objfile.
 294    This hangs off of dwarf2_objfile_data_key.
 295
 296    Some DWARF data cannot (currently) be shared across objfiles.  Such
 297    data is stored in this object.  */
 298
 299 struct dwarf2_per_objfile
 300 {
 301   dwarf2_per_objfile (struct objfile *objfile, dwarf2_per_bfd *per_bfd)
 302     : objfile (objfile), per_bfd (per_bfd)
 303   {}
 304
 305   /* Return pointer to string at .debug_line_str offset as read from BUF.
 306      BUF is assumed to be in a compilation unit described by CU_HEADER.
 307      Return *BYTES_READ_PTR count of bytes read from BUF.  */
 308   const char *read_line_string (const gdb_byte *buf,
 309                                 const struct comp_unit_head *cu_header,
 310                                 unsigned int *bytes_read_ptr);
 311
 312   /* Resize the M_SYMTABS vector to the needed size (the number of partial
 313      symtabs allocated by the per-bfd).  */
 314   void resize_symtabs ()
 315   {
 316     /* The symtabs vector should only grow, not shrink.  */
 317     gdb_assert (per_bfd->num_psymtabs () >= m_symtabs.size ());
 318
 319     m_symtabs.resize (per_bfd->num_psymtabs ());
 320   }
 321
 322   /* Return true if the symtab corresponding to PER_CU has been set,
 323      false otherwise.  */
 324   bool symtab_set_p (const dwarf2_per_cu_data *per_cu) const;
 325
 326   /* Return the compunit_symtab associated to PER_CU, if it has been created.  */
 327   compunit_symtab *get_symtab (const dwarf2_per_cu_data *per_cu) const;
 328
 329   /* Set the compunit_symtab associated to PER_CU.  */
 330   void set_symtab (const dwarf2_per_cu_data *per_cu, compunit_symtab *symtab);
 331
 332   /* Get the type_unit_group_unshareable corresponding to TU_GROUP.  If one
 333      does not exist, create it.  */
 334   type_unit_group_unshareable *get_type_unit_group_unshareable
 335     (type_unit_group *tu_group);
 336
 337   struct type *get_type_for_signatured_type (signatured_type *sig_type) const;
 338
 339   void set_type_for_signatured_type (signatured_type *sig_type,
 340                                      struct type *type);
 341
 342   /* Find an integer type SIZE_IN_BYTES bytes in size and return it.
 343      UNSIGNED_P controls if the integer is unsigned or not.  */
 344   struct type *int_type (int size_in_bytes, bool unsigned_p) const;
 345
 346   /* Back link.  */
 347   struct objfile *objfile;
 348
 349   /* Pointer to the data that is (possibly) shared between this objfile and
 350      other objfiles backed by the same BFD.  */
 351   struct dwarf2_per_bfd *per_bfd;
 352
 353   /* Table mapping type DIEs to their struct type *.
 354      This is nullptr if not allocated yet.
 355      The mapping is done via (CU/TU + DIE offset) -> type.  */
 356   htab_up die_type_hash;
 357
 358 private:
 359   /* Hold the corresponding compunit_symtab for each CU or TU.  This
 360      is indexed by dwarf2_per_cu_data::index.  A NULL value means
 361      that the CU/TU has not been expanded yet.  */
 362   std::vector<compunit_symtab *> m_symtabs;
 363
 364   /* Map from a type unit group to the corresponding unshared
 365      structure.  */
 366   typedef std::unique_ptr<type_unit_group_unshareable>
 367     type_unit_group_unshareable_up;
 368
 369   std::unordered_map<type_unit_group *, type_unit_group_unshareable_up>
 370     m_type_units;
 371
 372   /* Map from signatured types to the corresponding struct type.  */
 373   std::unordered_map<signatured_type *, struct type *> m_type_map;
 374 };
 375
 376 /* Get the dwarf2_per_objfile associated to OBJFILE.  */
 377
 378 dwarf2_per_objfile *get_dwarf2_per_objfile (struct objfile *objfile);
 379
 380 /* A partial symtab specialized for DWARF.  */
 381 struct dwarf2_psymtab : public partial_symtab
 382 {
 383   dwarf2_psymtab (const char *filename, struct objfile *objfile,
 384                   dwarf2_per_cu_data *per_cu)
 385     : partial_symtab (filename, objfile, 0),
 386       per_cu_data (per_cu)
 387   {
 388   }
 389
 390   void read_symtab (struct objfile *) override;
 391   void expand_psymtab (struct objfile *) override;
 392   bool readin_p (struct objfile *) const override;
 393   compunit_symtab *get_compunit_symtab (struct objfile *) const override;
 394
 395   struct dwarf2_per_cu_data *per_cu_data;
 396 };
 397
 398 /* Persistent data held for a compilation unit, even when not
 399    processing it.  We put a pointer to this structure in the
 400    psymtab.  */
 401
 402 struct dwarf2_per_cu_data
 403 {
 404   /* The start offset and length of this compilation unit.
 405      NOTE: Unlike comp_unit_head.length, this length includes
 406      initial_length_size.
 407      If the DIE refers to a DWO file, this is always of the original die,
 408      not the DWO file.  */
 409   sect_offset sect_off;
 410   unsigned int length;
 411
 412   /* DWARF standard version this data has been read from (such as 4 or 5).  */
 413   short dwarf_version;
 414
 415   /* Flag indicating this compilation unit will be read in before
 416      any of the current compilation units are processed.  */
 417   unsigned int queued : 1;
 418
 419   /* This flag will be set when reading partial DIEs if we need to load
 420      absolutely all DIEs for this compilation unit, instead of just the ones
 421      we think are interesting.  It gets set if we look for a DIE in the
 422      hash table and don't find it.  */
 423   unsigned int load_all_dies : 1;
 424
 425   /* Non-zero if this CU is from .debug_types.
 426      Struct dwarf2_per_cu_data is contained in struct signatured_type iff
 427      this is non-zero.  */
 428   unsigned int is_debug_types : 1;
 429
 430   /* Non-zero if this CU is from the .dwz file.  */
 431   unsigned int is_dwz : 1;
 432
 433   /* Non-zero if reading a TU directly from a DWO file, bypassing the stub.
 434      This flag is only valid if is_debug_types is true.
 435      We can't read a CU directly from a DWO file: There are required
 436      attributes in the stub.  */
 437   unsigned int reading_dwo_directly : 1;
 438
 439   /* Non-zero if the TU has been read.
 440      This is used to assist the "Stay in DWO Optimization" for Fission:
 441      When reading a DWO, it's faster to read TUs from the DWO instead of
 442      fetching them from random other DWOs (due to comdat folding).
 443      If the TU has already been read, the optimization is unnecessary
 444      (and unwise - we don't want to change where gdb thinks the TU lives
 445      "midflight").
 446      This flag is only valid if is_debug_types is true.  */
 447   unsigned int tu_read : 1;
 448
 449   /* Our index in the unshared "symtabs" vector.  */
 450   unsigned index;
 451
 452   /* The section this CU/TU lives in.
 453      If the DIE refers to a DWO file, this is always the original die,
 454      not the DWO file.  */
 455   struct dwarf2_section_info *section;
 456
 457   /* Set to non-NULL iff this CU is currently loaded.  When it gets freed out
 458      of the CU cache it gets reset to NULL again.  This is left as NULL for
 459      dummy CUs (a CU header, but nothing else).  */
 460   struct dwarf2_cu *cu;
 461
 462   /* The unit type of this CU.  */
 463   enum dwarf_unit_type unit_type;
 464
 465   /* The language of this CU.  */
 466   enum language lang;
 467
 468   /* Backlink to the owner of this.  */
 469   dwarf2_per_bfd *per_bfd;
 470
 471   /* When dwarf2_per_bfd::using_index is true, the 'quick' field
 472      is active.  Otherwise, the 'psymtab' field is active.  */
 473   union
 474   {
 475     /* The partial symbol table associated with this compilation unit,
 476        or NULL for unread partial units.  */
 477     dwarf2_psymtab *psymtab;
 478
 479     /* Data needed by the "quick" functions.  */
 480     struct dwarf2_per_cu_quick_data *quick;
 481   } v;
 482
 483   /* The CUs we import using DW_TAG_imported_unit.  This is filled in
 484      while reading psymtabs, used to compute the psymtab dependencies,
 485      and then cleared.  Then it is filled in again while reading full
 486      symbols, and only deleted when the objfile is destroyed.
 487
 488      This is also used to work around a difference between the way gold
 489      generates .gdb_index version <=7 and the way gdb does.  Arguably this
 490      is a gold bug.  For symbols coming from TUs, gold records in the index
 491      the CU that includes the TU instead of the TU itself.  This breaks
 492      dw2_lookup_symbol: It assumes that if the index says symbol X lives
 493      in CU/TU Y, then one need only expand Y and a subsequent lookup in Y
 494      will find X.  Alas TUs live in their own symtab, so after expanding CU Y
 495      we need to look in TU Z to find X.  Fortunately, this is akin to
 496      DW_TAG_imported_unit, so we just use the same mechanism: For
 497      .gdb_index version <=7 this also records the TUs that the CU referred
 498      to.  Concurrently with this change gdb was modified to emit version 8
 499      indices so we only pay a price for gold generated indices.
 500      http://sourceware.org/bugzilla/show_bug.cgi?id=15021.
 501
 502      This currently needs to be a public member due to how
 503      dwarf2_per_cu_data is allocated and used.  Ideally in future things
 504      could be refactored to make this private.  Until then please try to
 505      avoid direct access to this member, and instead use the helper
 506      functions above.  */
 507   std::vector <dwarf2_per_cu_data *> *imported_symtabs;
 508
 509   /* Return true of IMPORTED_SYMTABS is empty or not yet allocated.  */
 510   bool imported_symtabs_empty () const
 511   {
 512     return (imported_symtabs == nullptr || imported_symtabs->empty ());
 513   }
 514
 515   /* Push P to the back of IMPORTED_SYMTABS, allocated IMPORTED_SYMTABS
 516      first if required.  */
 517   void imported_symtabs_push (dwarf2_per_cu_data *p)
 518   {
 519     if (imported_symtabs == nullptr)
 520       imported_symtabs = new std::vector <dwarf2_per_cu_data *>;
 521     imported_symtabs->push_back (p);
 522   }
 523
 524   /* Return the size of IMPORTED_SYMTABS if it is allocated, otherwise
 525      return 0.  */
 526   size_t imported_symtabs_size () const
 527   {
 528     if (imported_symtabs == nullptr)
 529       return 0;
 530     return imported_symtabs->size ();
 531   }
 532
 533   /* Delete IMPORTED_SYMTABS and set the pointer back to nullptr.  */
 534   void imported_symtabs_free ()
 535   {
 536     delete imported_symtabs;
 537     imported_symtabs = nullptr;
 538   }
 539
 540   /* Return the address size given in the compilation unit header for
 541      this CU.  */
 542   int addr_size () const;
 543
 544   /* Return the offset size given in the compilation unit header for
 545      this CU.  */
 546   int offset_size () const;
 547
 548   /* Return the DW_FORM_ref_addr size given in the compilation unit
 549      header for this CU.  */
 550   int ref_addr_size () const;
 551
 552   /* Return DWARF version number of this CU.  */
 553   short version () const
 554   {
 555     return dwarf_version;
 556   }
 557
 558   /* A type unit group has a per_cu object that is recognized by
 559      having no section.  */
 560   bool type_unit_group_p () const
 561   {
 562     return section == nullptr;
 563   }
 564 };
 565
 566 /* Entry in the signatured_types hash table.  */
 567
 568 struct signatured_type
 569 {
 570   /* The "per_cu" object of this type.
 571      This struct is used iff per_cu.is_debug_types.
 572      N.B.: This is the first member so that it's easy to convert pointers
 573      between them.  */
 574   struct dwarf2_per_cu_data per_cu;
 575
 576   /* The type's signature.  */
 577   ULONGEST signature;
 578
 579   /* Offset in the TU of the type's DIE, as read from the TU header.
 580      If this TU is a DWO stub and the definition lives in a DWO file
 581      (specified by DW_AT_GNU_dwo_name), this value is unusable.  */
 582   cu_offset type_offset_in_tu;
 583
 584   /* Offset in the section of the type's DIE.
 585      If the definition lives in a DWO file, this is the offset in the
 586      .debug_types.dwo section.
 587      The value is zero until the actual value is known.
 588      Zero is otherwise not a valid section offset.  */
 589   sect_offset type_offset_in_section;
 590
 591   /* Type units are grouped by their DW_AT_stmt_list entry so that they
 592      can share them.  This points to the containing symtab.  */
 593   struct type_unit_group *type_unit_group;
 594
 595   /* Containing DWO unit.
 596      This field is valid iff per_cu.reading_dwo_directly.  */
 597   struct dwo_unit *dwo_unit;
 598 };
 599
 600 /* Open the separate '.dwz' debug file, if needed.  Return NULL if
 601    there is no .gnu_debugaltlink section in the file.  Error if there
 602    is such a section but the file cannot be found.  */
 603
 604 extern dwz_file *dwarf2_get_dwz_file (dwarf2_per_bfd *per_bfd);
 605
 606 /* Return the type of the DIE at DIE_OFFSET in the CU named by
 607    PER_CU.  */
 608
 609 struct type *dwarf2_get_die_type (cu_offset die_offset,
 610                                   dwarf2_per_cu_data *per_cu,
 611                                   dwarf2_per_objfile *per_objfile);
 612
 613 /* Given an index in .debug_addr, fetch the value.
 614    NOTE: This can be called during dwarf expression evaluation,
 615    long after the debug information has been read, and thus per_cu->cu
 616    may no longer exist.  */
 617
 618 CORE_ADDR dwarf2_read_addr_index (dwarf2_per_cu_data *per_cu,
 619                                   dwarf2_per_objfile *dwarf2_per_objfile,
 620                                   unsigned int addr_index);
 621
 622 /* Return DWARF block referenced by DW_AT_location of DIE at SECT_OFF at PER_CU.
 623    Returned value is intended for DW_OP_call*.  Returned
 624    dwarf2_locexpr_baton->data has lifetime of
 625    PER_CU->DWARF2_PER_OBJFILE->OBJFILE.  */
 626
 627 struct dwarf2_locexpr_baton dwarf2_fetch_die_loc_sect_off
 628   (sect_offset sect_off, dwarf2_per_cu_data *per_cu,
 629    dwarf2_per_objfile *per_objfile,
 630    CORE_ADDR (*get_frame_pc) (void *baton),
 631    void *baton, bool resolve_abstract_p = false);
 632
 633 /* Like dwarf2_fetch_die_loc_sect_off, but take a CU
 634    offset.  */
 635
 636 struct dwarf2_locexpr_baton dwarf2_fetch_die_loc_cu_off
 637   (cu_offset offset_in_cu, dwarf2_per_cu_data *per_cu,
 638    dwarf2_per_objfile *per_objfile,
 639    CORE_ADDR (*get_frame_pc) (void *baton),
 640    void *baton);
 641
 642 /* If the DIE at SECT_OFF in PER_CU has a DW_AT_const_value, return a
 643    pointer to the constant bytes and set LEN to the length of the
 644    data.  If memory is needed, allocate it on OBSTACK.  If the DIE
 645    does not have a DW_AT_const_value, return NULL.  */
 646
 647 extern const gdb_byte *dwarf2_fetch_constant_bytes
 648   (sect_offset sect_off, dwarf2_per_cu_data *per_cu,
 649    dwarf2_per_objfile *per_objfile, obstack *obstack,
 650    LONGEST *len);
 651
 652 /* Return the type of the die at SECT_OFF in PER_CU.  Return NULL if no
 653    valid type for this die is found.  */
 654
 655 struct type *dwarf2_fetch_die_type_sect_off
 656   (sect_offset sect_off, dwarf2_per_cu_data *per_cu,
 657    dwarf2_per_objfile *per_objfile);
 658
 659 /* When non-zero, dump line number entries as they are read in.  */
 660 extern unsigned int dwarf_line_debug;
 661
 662 #endif /* DWARF2READ_H */