gdb/psympriv.h

   1 /* Private partial symbol table definitions.
   2
   3    Copyright (C) 2009-2020 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 PSYMPRIV_H
  21 #define PSYMPRIV_H
  22
  23 #include "psymtab.h"
  24 #include "objfiles.h"
  25 #include "gdbsupport/gdb_string_view.h"
  26
  27 /* A partial_symbol records the name, domain, and address class of
  28    symbols whose types we have not parsed yet.  For functions, it also
  29    contains their memory address, so we can find them from a PC value.
  30    Each partial_symbol sits in a partial_symtab, all of which are chained
  31    on a  partial symtab list and which points to the corresponding
  32    normal symtab once the partial_symtab has been referenced.  */
  33
  34 /* This structure is space critical.  See space comments at the top of
  35    symtab.h.  */
  36
  37 struct partial_symbol
  38 {
  39   /* Return the section for this partial symbol, or nullptr if no
  40      section has been set.  */
  41   struct obj_section *obj_section (struct objfile *objfile) const
  42   {
  43     if (ginfo.section >= 0)
  44       return &objfile->sections[ginfo.section];
  45     return nullptr;
  46   }
  47
  48   /* Return the unrelocated address of this partial symbol.  */
  49   CORE_ADDR unrelocated_address () const
  50   {
  51     return ginfo.value.address;
  52   }
  53
  54   /* Return the address of this partial symbol, relocated according to
  55      the offsets provided in OBJFILE.  */
  56   CORE_ADDR address (const struct objfile *objfile) const
  57   {
  58     return ginfo.value.address + objfile->section_offsets[ginfo.section];
  59   }
  60
  61   /* Set the address of this partial symbol.  The address must be
  62      unrelocated.  */
  63   void set_unrelocated_address (CORE_ADDR addr)
  64   {
  65     ginfo.value.address = addr;
  66   }
  67
  68   /* Note that partial_symbol does not derive from general_symbol_info
  69      due to the bcache.  See add_psymbol_to_bcache.  */
  70
  71   struct general_symbol_info ginfo;
  72
  73   /* Name space code.  */
  74
  75   ENUM_BITFIELD(domain_enum_tag) domain : SYMBOL_DOMAIN_BITS;
  76
  77   /* Address class (for info_symbols).  Note that we don't allow
  78      synthetic "aclass" values here at present, simply because there's
  79      no need.  */
  80
  81   ENUM_BITFIELD(address_class) aclass : SYMBOL_ACLASS_BITS;
  82 };
  83
  84 /* A convenience enum to give names to some constants used when
  85    searching psymtabs.  This is internal to psymtab and should not be
  86    used elsewhere.  */
  87
  88 enum psymtab_search_status
  89   {
  90     PST_NOT_SEARCHED,
  91     PST_SEARCHED_AND_FOUND,
  92     PST_SEARCHED_AND_NOT_FOUND
  93   };
  94
  95 /* Each source file that has not been fully read in is represented by
  96    a partial_symtab.  This contains the information on where in the
  97    executable the debugging symbols for a specific file are, and a
  98    list of names of global symbols which are located in this file.
  99    They are all chained on partial symtab lists.
 100
 101    Even after the source file has been read into a symtab, the
 102    partial_symtab remains around.  They are allocated on an obstack,
 103    objfile_obstack.  */
 104
 105 struct partial_symtab
 106 {
 107   /* Return the raw low text address of this partial_symtab.  */
 108   CORE_ADDR raw_text_low () const
 109   {
 110     return m_text_low;
 111   }
 112
 113   /* Return the raw high text address of this partial_symtab.  */
 114   CORE_ADDR raw_text_high () const
 115   {
 116     return m_text_high;
 117   }
 118
 119   /* Return the relocated low text address of this partial_symtab.  */
 120   CORE_ADDR text_low (struct objfile *objfile) const
 121   {
 122     return m_text_low + objfile->section_offsets[SECT_OFF_TEXT (objfile)];
 123   }
 124
 125   /* Return the relocated high text address of this partial_symtab.  */
 126   CORE_ADDR text_high (struct objfile *objfile) const
 127   {
 128     return m_text_high + objfile->section_offsets[SECT_OFF_TEXT (objfile)];
 129   }
 130
 131   /* Set the low text address of this partial_symtab.  */
 132   void set_text_low (CORE_ADDR addr)
 133   {
 134     m_text_low = addr;
 135     text_low_valid = 1;
 136   }
 137
 138   /* Set the hight text address of this partial_symtab.  */
 139   void set_text_high (CORE_ADDR addr)
 140   {
 141     m_text_high = addr;
 142     text_high_valid = 1;
 143   }
 144
 145
 146   /* Chain of all existing partial symtabs.  */
 147
 148   struct partial_symtab *next;
 149
 150   /* Name of the source file which this partial_symtab defines,
 151      or if the psymtab is anonymous then a descriptive name for
 152      debugging purposes, or "".  It must not be NULL.  */
 153
 154   const char *filename;
 155
 156   /* Full path of the source file.  NULL if not known.  */
 157
 158   char *fullname;
 159
 160   /* Directory in which it was compiled, or NULL if we don't know.  */
 161
 162   const char *dirname;
 163
 164   /* Range of text addresses covered by this file; texthigh is the
 165      beginning of the next section.  Do not use if PSYMTABS_ADDRMAP_SUPPORTED
 166      is set.  Do not refer directly to these fields.  Instead, use the
 167      accessors.  The validity of these fields is determined by the
 168      text_low_valid and text_high_valid fields; these are located later
 169      in this structure for better packing.  */
 170
 171   CORE_ADDR m_text_low;
 172   CORE_ADDR m_text_high;
 173
 174   /* If NULL, this is an ordinary partial symbol table.
 175
 176      If non-NULL, this holds a single includer of this partial symbol
 177      table, and this partial symbol table is a shared one.
 178
 179      A shared psymtab is one that is referenced by multiple other
 180      psymtabs, and which conceptually has its contents directly
 181      included in those.
 182
 183      Shared psymtabs have special semantics.  When a search finds a
 184      symbol in a shared table, we instead return one of the non-shared
 185      tables that include this one.
 186
 187      A shared psymtabs can be referred to by other shared ones.
 188
 189      The psymtabs that refer to a shared psymtab will list the shared
 190      psymtab in their 'dependencies' array.
 191
 192      In DWARF terms, a shared psymtab is a DW_TAG_partial_unit; but
 193      of course using a name based on that would be too confusing, so
 194      "shared" was chosen instead.
 195
 196      Only a single user is needed because, when expanding a shared
 197      psymtab, we only need to expand its "canonical" non-shared user.
 198      The choice of which one should be canonical is left to the
 199      debuginfo reader; it can be arbitrary.  */
 200
 201   struct partial_symtab *user;
 202
 203   /* Array of pointers to all of the partial_symtab's which this one
 204      depends on.  Since this array can only be set to previous or
 205      the current (?) psymtab, this dependency tree is guaranteed not
 206      to have any loops.  "depends on" means that symbols must be read
 207      for the dependencies before being read for this psymtab; this is
 208      for type references in stabs, where if foo.c includes foo.h, declarations
 209      in foo.h may use type numbers defined in foo.c.  For other debugging
 210      formats there may be no need to use dependencies.  */
 211
 212   struct partial_symtab **dependencies;
 213
 214   int number_of_dependencies;
 215
 216   /* Global symbol list.  This list will be sorted after readin to
 217      improve access.  Binary search will be the usual method of
 218      finding a symbol within it.  globals_offset is an integer offset
 219      within global_psymbols[].  */
 220
 221   int globals_offset;
 222   int n_global_syms;
 223
 224   /* Static symbol list.  This list will *not* be sorted after readin;
 225      to find a symbol in it, exhaustive search must be used.  This is
 226      reasonable because searches through this list will eventually
 227      lead to either the read in of a files symbols for real (assumed
 228      to take a *lot* of time; check) or an error (and we don't care
 229      how long errors take).  This is an offset and size within
 230      static_psymbols[].  */
 231
 232   int statics_offset;
 233   int n_static_syms;
 234
 235   /* Non-zero if the symtab corresponding to this psymtab has been
 236      readin.  This is located here so that this structure packs better
 237      on 64-bit systems.  */
 238
 239   unsigned char readin;
 240
 241   /* True iff objfile->psymtabs_addrmap is properly populated for this
 242      partial_symtab.  For discontiguous overlapping psymtabs is the only usable
 243      info in PSYMTABS_ADDRMAP.  */
 244
 245   unsigned char psymtabs_addrmap_supported;
 246
 247   /* True if the name of this partial symtab is not a source file name.  */
 248
 249   unsigned char anonymous;
 250
 251   /* A flag that is temporarily used when searching psymtabs.  */
 252
 253   ENUM_BITFIELD (psymtab_search_status) searched_flag : 2;
 254
 255   /* Validity of the m_text_low and m_text_high fields.  */
 256
 257   unsigned int text_low_valid : 1;
 258   unsigned int text_high_valid : 1;
 259
 260   /* Pointer to compunit eventually allocated for this source file, 0 if
 261      !readin or if we haven't looked for the symtab after it was readin.  */
 262
 263   struct compunit_symtab *compunit_symtab;
 264
 265   /* Pointer to function which will read in the symtab corresponding to
 266      this psymtab.  */
 267
 268   void (*read_symtab) (struct partial_symtab *, struct objfile *);
 269
 270   /* Information that lets read_symtab() locate the part of the symbol table
 271      that this psymtab corresponds to.  This information is private to the
 272      format-dependent symbol reading routines.  For further detail examine
 273      the various symbol reading modules.  */
 274
 275   void *read_symtab_private;
 276 };
 277
 278 /* Specify whether a partial psymbol should be allocated on the global
 279    list or the static list.  */
 280
 281 enum class psymbol_placement
 282 {
 283   STATIC,
 284   GLOBAL
 285 };
 286
 287 /* Add a symbol to the partial symbol table of OBJFILE.
 288
 289    If COPY_NAME is true, make a copy of NAME, otherwise use the passed
 290    reference.
 291
 292    THECLASS is the type of symbol.
 293
 294    SECTION is the index of the section of OBJFILE in which the symbol is found.
 295
 296    WHERE determines whether the symbol goes in the list of static or global
 297    partial symbols of OBJFILE.
 298
 299    COREADDR is the address of the symbol.  For partial symbols that don't have
 300    an address, zero is passed.
 301
 302    LANGUAGE is the language from which the symbol originates.  This will
 303    influence, amongst other things, how the symbol name is demangled. */
 304
 305 extern void add_psymbol_to_list (gdb::string_view name,
 306                                  bool copy_name, domain_enum domain,
 307                                  enum address_class theclass,
 308                                  short section,
 309                                  psymbol_placement where,
 310                                  CORE_ADDR coreaddr,
 311                                  enum language language,
 312                                  struct objfile *objfile);
 313
 314 /* Initialize storage for partial symbols.  If partial symbol storage
 315    has already been initialized, this does nothing.  TOTAL_SYMBOLS is
 316    an estimate of how many symbols there will be.  */
 317
 318 extern void init_psymbol_list (struct objfile *objfile, int total_symbols);
 319
 320 extern struct partial_symtab *start_psymtab_common (struct objfile *,
 321                                                     const char *, CORE_ADDR);
 322
 323 extern void end_psymtab_common (struct objfile *, struct partial_symtab *);
 324
 325 /* Allocate a new partial symbol table associated with OBJFILE.
 326    FILENAME (which must be non-NULL) is the filename of this partial
 327    symbol table; it is copied into the appropriate storage.  A new
 328    partial symbol table is returned; aside from "next" and "filename",
 329    its fields are initialized to zero.  */
 330
 331 extern struct partial_symtab *allocate_psymtab (const char *filename,
 332                                                 struct objfile *objfile)
 333   ATTRIBUTE_NONNULL (1);
 334
 335 static inline void
 336 discard_psymtab (struct objfile *objfile, struct partial_symtab *pst)
 337 {
 338   objfile->partial_symtabs->discard_psymtab (pst);
 339 }
 340
 341 /* Used when recording partial symbol tables.  On destruction,
 342    discards any partial symbol tables that have been built.  However,
 343    the tables can be kept by calling the "keep" method.  */
 344 class psymtab_discarder
 345 {
 346  public:
 347
 348   psymtab_discarder (struct objfile *objfile)
 349     : m_objfile (objfile),
 350       m_psymtab (objfile->partial_symtabs->psymtabs)
 351   {
 352   }
 353
 354   ~psymtab_discarder ()
 355   {
 356     if (m_objfile != NULL)
 357       m_objfile->partial_symtabs->discard_psymtabs_to (m_psymtab);
 358   }
 359
 360   /* Keep any partial symbol tables that were built.  */
 361   void keep ()
 362   {
 363     m_objfile = NULL;
 364   }
 365
 366  private:
 367
 368   /* The objfile.  If NULL this serves as a sentinel to indicate that
 369      the psymtabs should be kept.  */
 370   struct objfile *m_objfile;
 371   /* How far back to free.  */
 372   struct partial_symtab *m_psymtab;
 373 };
 374
 375 #endif /* PSYMPRIV_H */