gdb/psympriv.h

   1 /* Private partial symbol table definitions.
   2
   3    Copyright (C) 2009-2019 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
  26 /* A partial_symbol records the name, domain, and address class of
  27    symbols whose types we have not parsed yet.  For functions, it also
  28    contains their memory address, so we can find them from a PC value.
  29    Each partial_symbol sits in a partial_symtab, all of which are chained
  30    on a  partial symtab list and which points to the corresponding
  31    normal symtab once the partial_symtab has been referenced.  */
  32
  33 /* This structure is space critical.  See space comments at the top of
  34    symtab.h.  */
  35
  36 struct partial_symbol
  37 {
  38   /* Return the section for this partial symbol, or nullptr if no
  39      section has been set.  */
  40   struct obj_section *obj_section (struct objfile *objfile) const
  41   {
  42     if (ginfo.section >= 0)
  43       return &objfile->sections[ginfo.section];
  44     return nullptr;
  45   }
  46
  47   /* Return the unrelocated address of this partial symbol.  */
  48   CORE_ADDR unrelocated_address () const
  49   {
  50     return ginfo.value.address;
  51   }
  52
  53   /* Return the address of this partial symbol, relocated according to
  54      the offsets provided in OBJFILE.  */
  55   CORE_ADDR address (const struct objfile *objfile) const
  56   {
  57     return (ginfo.value.address
  58             + ANOFFSET (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 + ANOFFSET (objfile->section_offsets,
 123                                   SECT_OFF_TEXT (objfile));
 124   }
 125
 126   /* Return the relocated high text address of this partial_symtab.  */
 127   CORE_ADDR text_high (struct objfile *objfile) const
 128   {
 129     return m_text_high + ANOFFSET (objfile->section_offsets,
 130                                    SECT_OFF_TEXT (objfile));
 131   }
 132
 133   /* Set the low text address of this partial_symtab.  */
 134   void set_text_low (CORE_ADDR addr)
 135   {
 136     m_text_low = addr;
 137     text_low_valid = 1;
 138   }
 139
 140   /* Set the hight text address of this partial_symtab.  */
 141   void set_text_high (CORE_ADDR addr)
 142   {
 143     m_text_high = addr;
 144     text_high_valid = 1;
 145   }
 146
 147
 148   /* Chain of all existing partial symtabs.  */
 149
 150   struct partial_symtab *next;
 151
 152   /* Name of the source file which this partial_symtab defines,
 153      or if the psymtab is anonymous then a descriptive name for
 154      debugging purposes, or "".  It must not be NULL.  */
 155
 156   const char *filename;
 157
 158   /* Full path of the source file.  NULL if not known.  */
 159
 160   char *fullname;
 161
 162   /* Directory in which it was compiled, or NULL if we don't know.  */
 163
 164   const char *dirname;
 165
 166   /* Range of text addresses covered by this file; texthigh is the
 167      beginning of the next section.  Do not use if PSYMTABS_ADDRMAP_SUPPORTED
 168      is set.  Do not refer directly to these fields.  Instead, use the
 169      accessors.  The validity of these fields is determined by the
 170      text_low_valid and text_high_valid fields; these are located later
 171      in this structure for better packing.  */
 172
 173   CORE_ADDR m_text_low;
 174   CORE_ADDR m_text_high;
 175
 176   /* If NULL, this is an ordinary partial symbol table.
 177
 178      If non-NULL, this holds a single includer of this partial symbol
 179      table, and this partial symbol table is a shared one.
 180
 181      A shared psymtab is one that is referenced by multiple other
 182      psymtabs, and which conceptually has its contents directly
 183      included in those.
 184
 185      Shared psymtabs have special semantics.  When a search finds a
 186      symbol in a shared table, we instead return one of the non-shared
 187      tables that include this one.
 188
 189      A shared psymtabs can be referred to by other shared ones.
 190
 191      The psymtabs that refer to a shared psymtab will list the shared
 192      psymtab in their 'dependencies' array.
 193
 194      In DWARF terms, a shared psymtab is a DW_TAG_partial_unit; but
 195      of course using a name based on that would be too confusing, so
 196      "shared" was chosen instead.
 197
 198      Only a single user is needed because, when expanding a shared
 199      psymtab, we only need to expand its "canonical" non-shared user.
 200      The choice of which one should be canonical is left to the
 201      debuginfo reader; it can be arbitrary.  */
 202
 203   struct partial_symtab *user;
 204
 205   /* Array of pointers to all of the partial_symtab's which this one
 206      depends on.  Since this array can only be set to previous or
 207      the current (?) psymtab, this dependency tree is guaranteed not
 208      to have any loops.  "depends on" means that symbols must be read
 209      for the dependencies before being read for this psymtab; this is
 210      for type references in stabs, where if foo.c includes foo.h, declarations
 211      in foo.h may use type numbers defined in foo.c.  For other debugging
 212      formats there may be no need to use dependencies.  */
 213
 214   struct partial_symtab **dependencies;
 215
 216   int number_of_dependencies;
 217
 218   /* Global symbol list.  This list will be sorted after readin to
 219      improve access.  Binary search will be the usual method of
 220      finding a symbol within it.  globals_offset is an integer offset
 221      within global_psymbols[].  */
 222
 223   int globals_offset;
 224   int n_global_syms;
 225
 226   /* Static symbol list.  This list will *not* be sorted after readin;
 227      to find a symbol in it, exhaustive search must be used.  This is
 228      reasonable because searches through this list will eventually
 229      lead to either the read in of a files symbols for real (assumed
 230      to take a *lot* of time; check) or an error (and we don't care
 231      how long errors take).  This is an offset and size within
 232      static_psymbols[].  */
 233
 234   int statics_offset;
 235   int n_static_syms;
 236
 237   /* Non-zero if the symtab corresponding to this psymtab has been
 238      readin.  This is located here so that this structure packs better
 239      on 64-bit systems.  */
 240
 241   unsigned char readin;
 242
 243   /* True iff objfile->psymtabs_addrmap is properly populated for this
 244      partial_symtab.  For discontiguous overlapping psymtabs is the only usable
 245      info in PSYMTABS_ADDRMAP.  */
 246
 247   unsigned char psymtabs_addrmap_supported;
 248
 249   /* True if the name of this partial symtab is not a source file name.  */
 250
 251   unsigned char anonymous;
 252
 253   /* A flag that is temporarily used when searching psymtabs.  */
 254
 255   ENUM_BITFIELD (psymtab_search_status) searched_flag : 2;
 256
 257   /* Validity of the m_text_low and m_text_high fields.  */
 258
 259   unsigned int text_low_valid : 1;
 260   unsigned int text_high_valid : 1;
 261
 262   /* Pointer to compunit eventually allocated for this source file, 0 if
 263      !readin or if we haven't looked for the symtab after it was readin.  */
 264
 265   struct compunit_symtab *compunit_symtab;
 266
 267   /* Pointer to function which will read in the symtab corresponding to
 268      this psymtab.  */
 269
 270   void (*read_symtab) (struct partial_symtab *, struct objfile *);
 271
 272   /* Information that lets read_symtab() locate the part of the symbol table
 273      that this psymtab corresponds to.  This information is private to the
 274      format-dependent symbol reading routines.  For further detail examine
 275      the various symbol reading modules.  */
 276
 277   void *read_symtab_private;
 278 };
 279
 280 /* Specify whether a partial psymbol should be allocated on the global
 281    list or the static list.  */
 282
 283 enum class psymbol_placement
 284 {
 285   STATIC,
 286   GLOBAL
 287 };
 288
 289 /* Add any kind of symbol to a partial_symbol vector.  */
 290
 291 extern void add_psymbol_to_list (const char *, int,
 292                                  int, domain_enum,
 293                                  enum address_class,
 294                                  short /* section */,
 295                                  enum psymbol_placement,
 296                                  CORE_ADDR,
 297                                  enum language, struct objfile *);
 298
 299 /* Initialize storage for partial symbols.  If partial symbol storage
 300    has already been initialized, this does nothing.  TOTAL_SYMBOLS is
 301    an estimate of how many symbols there will be.  */
 302
 303 extern void init_psymbol_list (struct objfile *objfile, int total_symbols);
 304
 305 extern struct partial_symtab *start_psymtab_common (struct objfile *,
 306                                                     const char *, CORE_ADDR);
 307
 308 extern void end_psymtab_common (struct objfile *, struct partial_symtab *);
 309
 310 /* Allocate a new partial symbol table associated with OBJFILE.
 311    FILENAME (which must be non-NULL) is the filename of this partial
 312    symbol table; it is copied into the appropriate storage.  A new
 313    partial symbol table is returned; aside from "next" and "filename",
 314    its fields are initialized to zero.  */
 315
 316 extern struct partial_symtab *allocate_psymtab (const char *filename,
 317                                                 struct objfile *objfile)
 318   ATTRIBUTE_NONNULL (1);
 319
 320 static inline void
 321 discard_psymtab (struct objfile *objfile, struct partial_symtab *pst)
 322 {
 323   objfile->partial_symtabs->discard_psymtab (pst);
 324 }
 325
 326 /* Used when recording partial symbol tables.  On destruction,
 327    discards any partial symbol tables that have been built.  However,
 328    the tables can be kept by calling the "keep" method.  */
 329 class psymtab_discarder
 330 {
 331  public:
 332
 333   psymtab_discarder (struct objfile *objfile)
 334     : m_objfile (objfile),
 335       m_psymtab (objfile->partial_symtabs->psymtabs)
 336   {
 337   }
 338
 339   ~psymtab_discarder ()
 340   {
 341     if (m_objfile != NULL)
 342       m_objfile->partial_symtabs->discard_psymtabs_to (m_psymtab);
 343   }
 344
 345   /* Keep any partial symbol tables that were built.  */
 346   void keep ()
 347   {
 348     m_objfile = NULL;
 349   }
 350
 351  private:
 352
 353   /* The objfile.  If NULL this serves as a sentinel to indicate that
 354      the psymtabs should be kept.  */
 355   struct objfile *m_objfile;
 356   /* How far back to free.  */
 357   struct partial_symtab *m_psymtab;
 358 };
 359
 360 #endif /* PSYMPRIV_H */