gdb/minsyms.h

   1 /* Minimal symbol table definitions for GDB.
   2
   3    Copyright (C) 2011-2023 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 MINSYMS_H
  21 #define MINSYMS_H
  22
  23 struct type;
  24
  25 /* Several lookup functions return both a minimal symbol and the
  26    objfile in which it is found.  This structure is used in these
  27    cases.  */
  28
  29 struct bound_minimal_symbol
  30 {
  31   bound_minimal_symbol (struct minimal_symbol *msym, struct objfile *objf)
  32     : minsym (msym),
  33       objfile (objf)
  34   {
  35   }
  36
  37   bound_minimal_symbol () = default;
  38
  39   /* Return the address of the minimal symbol in the context of the objfile.  */
  40
  41   CORE_ADDR value_address () const
  42   {
  43     return this->minsym->value_address (this->objfile);
  44   }
  45
  46   /* The minimal symbol that was found, or NULL if no minimal symbol
  47      was found.  */
  48
  49   struct minimal_symbol *minsym = nullptr;
  50
  51   /* If MINSYM is not NULL, then this is the objfile in which the
  52      symbol is defined.  */
  53
  54   struct objfile *objfile = nullptr;
  55
  56   /* Return the obj_section from OBJFILE for MINSYM.  */
  57
  58   struct obj_section *obj_section () const
  59   {
  60     return minsym->obj_section (objfile);
  61   }
  62 };
  63
  64 /* This header declares most of the API for dealing with minimal
  65    symbols and minimal symbol tables.  A few things are declared
  66    elsewhere; see below.
  67
  68    A minimal symbol is a symbol for which there is no direct debug
  69    information.  For example, for an ELF binary, minimal symbols are
  70    created from the ELF symbol table.
  71
  72    For the definition of the minimal symbol structure, see struct
  73    minimal_symbol in symtab.h.
  74
  75    Minimal symbols are stored in tables attached to an objfile; see
  76    objfiles.h for details.  Code should generally treat these tables
  77    as opaque and use functions provided by minsyms.c to inspect them.
  78 */
  79
  80 struct msym_bunch;
  81
  82 /* An RAII-based object that is used to record minimal symbols while
  83    they are being read.  */
  84 class minimal_symbol_reader
  85 {
  86  public:
  87
  88   /* Prepare to start collecting minimal symbols.  This should be
  89      called by a symbol reader to initialize the minimal symbol
  90      module.  */
  91
  92   explicit minimal_symbol_reader (struct objfile *);
  93
  94   ~minimal_symbol_reader ();
  95
  96   /* Install the minimal symbols that have been collected into the
  97      given objfile.  */
  98
  99   void install ();
 100
 101   /* Record a new minimal symbol.  This is the "full" entry point;
 102      simpler convenience entry points are also provided below.
 103
 104      This returns a new minimal symbol.  It is ok to modify the returned
 105      minimal symbol (though generally not necessary).  It is not ok,
 106      though, to stash the pointer anywhere; as minimal symbols may be
 107      moved after creation.  The memory for the returned minimal symbol
 108      is still owned by the minsyms.c code, and should not be freed.
 109
 110      Arguments are:
 111
 112      NAME - the symbol's name
 113      COPY_NAME - if true, the minsym code must make a copy of NAME.  If
 114      false, then NAME must be NUL-terminated, and must have a lifetime
 115      that is at least as long as OBJFILE's lifetime.
 116      ADDRESS - the address of the symbol
 117      MS_TYPE - the type of the symbol
 118      SECTION - the symbol's section
 119   */
 120
 121   struct minimal_symbol *record_full (gdb::string_view name,
 122                                       bool copy_name,
 123                                       unrelocated_addr address,
 124                                       enum minimal_symbol_type ms_type,
 125                                       int section);
 126
 127   /* Like record_full, but:
 128      - computes the length of NAME
 129      - passes COPY_NAME = true,
 130      - and passes a default SECTION, depending on the type
 131
 132      This variant does not return the new symbol.  */
 133
 134   void record (const char *name, unrelocated_addr address,
 135                enum minimal_symbol_type ms_type);
 136
 137   /* Like record_full, but:
 138      - computes the length of NAME
 139      - passes COPY_NAME = true.
 140
 141      This variant does not return the new symbol.  */
 142
 143   void record_with_info (const char *name, unrelocated_addr address,
 144                          enum minimal_symbol_type ms_type,
 145                          int section)
 146   {
 147     record_full (name, true, address, ms_type, section);
 148   }
 149
 150  private:
 151
 152   DISABLE_COPY_AND_ASSIGN (minimal_symbol_reader);
 153
 154   struct objfile *m_objfile;
 155
 156   /* Bunch currently being filled up.
 157      The next field points to chain of filled bunches.  */
 158
 159   struct msym_bunch *m_msym_bunch;
 160
 161   /* Number of slots filled in current bunch.  */
 162
 163   int m_msym_bunch_index;
 164
 165   /* Total number of minimal symbols recorded so far for the
 166      objfile.  */
 167
 168   int m_msym_count;
 169 };
 170
 171 \f
 172
 173 /* Return whether MSYMBOL is a function/method.  If FUNC_ADDRESS_P is
 174    non-NULL, and the MSYMBOL is a function, then *FUNC_ADDRESS_P is
 175    set to the function's address, already resolved if MINSYM points to
 176    a function descriptor.  */
 177
 178 bool msymbol_is_function (struct objfile *objfile,
 179                           minimal_symbol *minsym,
 180                           CORE_ADDR *func_address_p = NULL);
 181
 182 /* Compute a hash code for the string argument.  Unlike htab_hash_string,
 183    this is a case-insensitive hash to support "set case-sensitive off".  */
 184
 185 unsigned int msymbol_hash (const char *);
 186
 187 /* Like msymbol_hash, but compute a hash code that is compatible with
 188    strcmp_iw.  */
 189
 190 unsigned int msymbol_hash_iw (const char *);
 191
 192 /* Compute the next hash value from previous HASH and the character C.  This
 193    is only a GDB in-memory computed value with no external files compatibility
 194    requirements.  */
 195
 196 #define SYMBOL_HASH_NEXT(hash, c)                       \
 197   ((hash) * 67 + TOLOWER ((unsigned char) (c)) - 113)
 198
 199 \f
 200
 201 /* Look through all the current minimal symbol tables and find the
 202    first minimal symbol that matches NAME.  If OBJF is non-NULL, limit
 203    the search to that objfile.  If SFILE is non-NULL, the only
 204    file-scope symbols considered will be from that source file (global
 205    symbols are still preferred).  Returns a bound minimal symbol that
 206    matches, or an empty bound minimal symbol if no match is found.  */
 207
 208 struct bound_minimal_symbol lookup_minimal_symbol (const char *,
 209                                                    const char *,
 210                                                    struct objfile *);
 211
 212 /* Like lookup_minimal_symbol, but searches all files and
 213    objfiles.  */
 214
 215 struct bound_minimal_symbol lookup_bound_minimal_symbol (const char *);
 216
 217 /* Look through all the current minimal symbol tables and find the
 218    first minimal symbol that matches NAME and has text type.  If OBJF
 219    is non-NULL, limit the search to that objfile.  Returns a bound
 220    minimal symbol that matches, or an "empty" bound minimal symbol
 221    otherwise.
 222
 223    This function only searches the mangled (linkage) names.  */
 224
 225 struct bound_minimal_symbol lookup_minimal_symbol_text (const char *,
 226                                                         struct objfile *);
 227
 228 /* Look through the minimal symbols in OBJF (and its separate debug
 229    objfiles) for a global (not file-local) minsym whose linkage name
 230    is NAME.  This is somewhat similar to lookup_minimal_symbol_text,
 231    only data symbols (not text symbols) are considered, and a non-NULL
 232    objfile is not accepted.  Returns a bound minimal symbol that
 233    matches, or an "empty" bound minimal symbol otherwise.  */
 234
 235 extern struct bound_minimal_symbol lookup_minimal_symbol_linkage
 236   (const char *name, struct objfile *objf)
 237   ATTRIBUTE_NONNULL (1) ATTRIBUTE_NONNULL (2);
 238
 239 /* A variant of lookup_minimal_symbol_linkage that iterates over all
 240    objfiles.  If ONLY_MAIN is true, then only an objfile with
 241    OBJF_MAINLINE will be considered.  */
 242
 243 extern struct bound_minimal_symbol lookup_minimal_symbol_linkage
 244   (const char *name, bool only_main)
 245   ATTRIBUTE_NONNULL (1);
 246
 247 /* Look through all the current minimal symbol tables and find the
 248    first minimal symbol that matches NAME and PC.  If OBJF is non-NULL,
 249    limit the search to that objfile.  Returns a pointer to the minimal
 250    symbol that matches, or NULL if no match is found.  */
 251
 252 struct minimal_symbol *lookup_minimal_symbol_by_pc_name
 253     (CORE_ADDR, const char *, struct objfile *);
 254
 255 enum class lookup_msym_prefer
 256 {
 257   /* Prefer mst_text symbols.  */
 258   TEXT,
 259
 260   /* Prefer mst_solib_trampoline symbols when there are text and
 261      trampoline symbols at the same address.  Otherwise prefer
 262      mst_text symbols.  */
 263   TRAMPOLINE,
 264
 265   /* Prefer mst_text_gnu_ifunc symbols when there are text and ifunc
 266      symbols at the same address.  Otherwise prefer mst_text
 267      symbols.  */
 268   GNU_IFUNC,
 269 };
 270
 271 /* Search through the minimal symbol table for each objfile and find
 272    the symbol whose address is the largest address that is still less
 273    than or equal to PC_IN, and which matches SECTION.  A matching symbol
 274    must either be zero sized and have address PC_IN, or PC_IN must fall
 275    within the range of addresses covered by the matching symbol.
 276
 277    If SECTION is NULL, this uses the result of find_pc_section
 278    instead.
 279
 280    The result has a non-NULL 'minsym' member if such a symbol is
 281    found, or NULL if PC is not in a suitable range.
 282
 283    See definition of lookup_msym_prefer for description of PREFER.  By
 284    default mst_text symbols are preferred.
 285
 286    If the PREVIOUS pointer is non-NULL, and no matching symbol is found,
 287    then the contents will be set to reference the closest symbol before
 288    PC_IN.  */
 289
 290 struct bound_minimal_symbol lookup_minimal_symbol_by_pc_section
 291   (CORE_ADDR pc_in,
 292    struct obj_section *section,
 293    lookup_msym_prefer prefer = lookup_msym_prefer::TEXT,
 294    bound_minimal_symbol *previous = nullptr);
 295
 296 /* Backward compatibility: search through the minimal symbol table
 297    for a matching PC (no section given).
 298
 299    This is a wrapper that calls lookup_minimal_symbol_by_pc_section
 300    with a NULL section argument.  */
 301
 302 struct bound_minimal_symbol lookup_minimal_symbol_by_pc (CORE_ADDR);
 303
 304 /* Iterate over all the minimal symbols in the objfile OBJF which
 305    match NAME.  Both the ordinary and demangled names of each symbol
 306    are considered.  The caller is responsible for canonicalizing NAME,
 307    should that need to be done.
 308
 309    For each matching symbol, CALLBACK is called with the symbol.  */
 310
 311 void iterate_over_minimal_symbols
 312     (struct objfile *objf, const lookup_name_info &name,
 313      gdb::function_view<bool (struct minimal_symbol *)> callback);
 314
 315 /* Compute the upper bound of MINSYM.  The upper bound is the last
 316    address thought to be part of the symbol.  If the symbol has a
 317    size, it is used.  Otherwise use the lesser of the next minimal
 318    symbol in the same section, or the end of the section, as the end
 319    of the function.  */
 320
 321 CORE_ADDR minimal_symbol_upper_bound (struct bound_minimal_symbol minsym);
 322
 323 /* Return the type of MSYMBOL, a minimal symbol of OBJFILE.  If
 324    ADDRESS_P is not NULL, set it to the MSYMBOL's resolved
 325    address.  */
 326
 327 type *find_minsym_type_and_address (minimal_symbol *msymbol, objfile *objf,
 328                                     CORE_ADDR *address_p);
 329
 330 #endif /* MINSYMS_H */