gdb/minsyms.h

   1 /* Minimal symbol table definitions for GDB.
   2
   3    Copyright (C) 2011-2021 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 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   /* The minimal symbol that was found, or NULL if no minimal symbol
  32      was found.  */
  33
  34   struct minimal_symbol *minsym;
  35
  36   /* If MINSYM is not NULL, then this is the objfile in which the
  37      symbol is defined.  */
  38
  39   struct objfile *objfile;
  40
  41   /* Return the obj_section from OBJFILE for MINSYM.  */
  42
  43   struct obj_section *obj_section () const
  44   {
  45     return minsym->obj_section (objfile);
  46   }
  47 };
  48
  49 /* This header declares most of the API for dealing with minimal
  50    symbols and minimal symbol tables.  A few things are declared
  51    elsewhere; see below.
  52
  53    A minimal symbol is a symbol for which there is no direct debug
  54    information.  For example, for an ELF binary, minimal symbols are
  55    created from the ELF symbol table.
  56
  57    For the definition of the minimal symbol structure, see struct
  58    minimal_symbol in symtab.h.
  59
  60    Minimal symbols are stored in tables attached to an objfile; see
  61    objfiles.h for details.  Code should generally treat these tables
  62    as opaque and use functions provided by minsyms.c to inspect them.
  63 */
  64
  65 struct msym_bunch;
  66
  67 /* An RAII-based object that is used to record minimal symbols while
  68    they are being read.  */
  69 class minimal_symbol_reader
  70 {
  71  public:
  72
  73   /* Prepare to start collecting minimal symbols.  This should be
  74      called by a symbol reader to initialize the minimal symbol
  75      module.  */
  76
  77   explicit minimal_symbol_reader (struct objfile *);
  78
  79   ~minimal_symbol_reader ();
  80
  81   /* Install the minimal symbols that have been collected into the
  82      given objfile.  */
  83
  84   void install ();
  85
  86   /* Record a new minimal symbol.  This is the "full" entry point;
  87      simpler convenience entry points are also provided below.
  88
  89      This returns a new minimal symbol.  It is ok to modify the returned
  90      minimal symbol (though generally not necessary).  It is not ok,
  91      though, to stash the pointer anywhere; as minimal symbols may be
  92      moved after creation.  The memory for the returned minimal symbol
  93      is still owned by the minsyms.c code, and should not be freed.
  94
  95      Arguments are:
  96
  97      NAME - the symbol's name
  98      COPY_NAME - if true, the minsym code must make a copy of NAME.  If
  99      false, then NAME must be NUL-terminated, and must have a lifetime
 100      that is at least as long as OBJFILE's lifetime.
 101      ADDRESS - the address of the symbol
 102      MS_TYPE - the type of the symbol
 103      SECTION - the symbol's section
 104   */
 105
 106   struct minimal_symbol *record_full (gdb::string_view name,
 107                                       bool copy_name,
 108                                       CORE_ADDR address,
 109                                       enum minimal_symbol_type ms_type,
 110                                       int section);
 111
 112   /* Like record_full, but:
 113      - computes the length of NAME
 114      - passes COPY_NAME = true,
 115      - and passes a default SECTION, depending on the type
 116
 117      This variant does not return the new symbol.  */
 118
 119   void record (const char *name, CORE_ADDR address,
 120                enum minimal_symbol_type ms_type);
 121
 122   /* Like record_full, but:
 123      - computes the length of NAME
 124      - passes COPY_NAME = true.
 125
 126      This variant does not return the new symbol.  */
 127
 128   void record_with_info (const char *name, CORE_ADDR address,
 129                          enum minimal_symbol_type ms_type,
 130                          int section)
 131   {
 132     record_full (name, true, address, ms_type, section);
 133   }
 134
 135  private:
 136
 137   DISABLE_COPY_AND_ASSIGN (minimal_symbol_reader);
 138
 139   struct objfile *m_objfile;
 140
 141   /* Bunch currently being filled up.
 142      The next field points to chain of filled bunches.  */
 143
 144   struct msym_bunch *m_msym_bunch;
 145
 146   /* Number of slots filled in current bunch.  */
 147
 148   int m_msym_bunch_index;
 149
 150   /* Total number of minimal symbols recorded so far for the
 151      objfile.  */
 152
 153   int m_msym_count;
 154 };
 155
 156 \f
 157
 158 /* Return whether MSYMBOL is a function/method.  If FUNC_ADDRESS_P is
 159    non-NULL, and the MSYMBOL is a function, then *FUNC_ADDRESS_P is
 160    set to the function's address, already resolved if MINSYM points to
 161    a function descriptor.  */
 162
 163 bool msymbol_is_function (struct objfile *objfile,
 164                           minimal_symbol *minsym,
 165                           CORE_ADDR *func_address_p = NULL);
 166
 167 /* Compute a hash code for the string argument.  Unlike htab_hash_string,
 168    this is a case-insensitive hash to support "set case-sensitive off".  */
 169
 170 unsigned int msymbol_hash (const char *);
 171
 172 /* Like msymbol_hash, but compute a hash code that is compatible with
 173    strcmp_iw.  */
 174
 175 unsigned int msymbol_hash_iw (const char *);
 176
 177 /* Compute the next hash value from previous HASH and the character C.  This
 178    is only a GDB in-memory computed value with no external files compatibility
 179    requirements.  */
 180
 181 #define SYMBOL_HASH_NEXT(hash, c)                       \
 182   ((hash) * 67 + TOLOWER ((unsigned char) (c)) - 113)
 183
 184 \f
 185
 186 /* Look through all the current minimal symbol tables and find the
 187    first minimal symbol that matches NAME.  If OBJF is non-NULL, limit
 188    the search to that objfile.  If SFILE is non-NULL, the only
 189    file-scope symbols considered will be from that source file (global
 190    symbols are still preferred).  Returns a bound minimal symbol that
 191    matches, or an empty bound minimal symbol if no match is found.  */
 192
 193 struct bound_minimal_symbol lookup_minimal_symbol (const char *,
 194                                                    const char *,
 195                                                    struct objfile *);
 196
 197 /* Like lookup_minimal_symbol, but searches all files and
 198    objfiles.  */
 199
 200 struct bound_minimal_symbol lookup_bound_minimal_symbol (const char *);
 201
 202 /* Look through all the current minimal symbol tables and find the
 203    first minimal symbol that matches NAME and has text type.  If OBJF
 204    is non-NULL, limit the search to that objfile.  Returns a bound
 205    minimal symbol that matches, or an "empty" bound minimal symbol
 206    otherwise.
 207
 208    This function only searches the mangled (linkage) names.  */
 209
 210 struct bound_minimal_symbol lookup_minimal_symbol_text (const char *,
 211                                                         struct objfile *);
 212
 213 /* Look through the minimal symbols in OBJF (and its separate debug
 214    objfiles) for a global (not file-local) minsym whose linkage name
 215    is NAME.  This is somewhat similar to lookup_minimal_symbol_text,
 216    only data symbols (not text symbols) are considered, and a non-NULL
 217    objfile is not accepted.  Returns a bound minimal symbol that
 218    matches, or an "empty" bound minimal symbol otherwise.  */
 219
 220 extern struct bound_minimal_symbol lookup_minimal_symbol_linkage
 221   (const char *name, struct objfile *objf)
 222   ATTRIBUTE_NONNULL (1) ATTRIBUTE_NONNULL (2);
 223
 224 /* Look through all the current minimal symbol tables and find the
 225    first minimal symbol that matches NAME and PC.  If OBJF is non-NULL,
 226    limit the search to that objfile.  Returns a pointer to the minimal
 227    symbol that matches, or NULL if no match is found.  */
 228
 229 struct minimal_symbol *lookup_minimal_symbol_by_pc_name
 230     (CORE_ADDR, const char *, struct objfile *);
 231
 232 enum class lookup_msym_prefer
 233 {
 234   /* Prefer mst_text symbols.  */
 235   TEXT,
 236
 237   /* Prefer mst_solib_trampoline symbols when there are text and
 238      trampoline symbols at the same address.  Otherwise prefer
 239      mst_text symbols.  */
 240   TRAMPOLINE,
 241
 242   /* Prefer mst_text_gnu_ifunc symbols when there are text and ifunc
 243      symbols at the same address.  Otherwise prefer mst_text
 244      symbols.  */
 245   GNU_IFUNC,
 246 };
 247
 248 /* Search through the minimal symbol table for each objfile and find
 249    the symbol whose address is the largest address that is still less
 250    than or equal to PC_IN, and which matches SECTION.  A matching symbol
 251    must either be zero sized and have address PC_IN, or PC_IN must fall
 252    within the range of addresses covered by the matching symbol.
 253
 254    If SECTION is NULL, this uses the result of find_pc_section
 255    instead.
 256
 257    The result has a non-NULL 'minsym' member if such a symbol is
 258    found, or NULL if PC is not in a suitable range.
 259
 260    See definition of lookup_msym_prefer for description of PREFER.  By
 261    default mst_text symbols are preferred.
 262
 263    If the PREVIOUS pointer is non-NULL, and no matching symbol is found,
 264    then the contents will be set to reference the closest symbol before
 265    PC_IN.  */
 266
 267 struct bound_minimal_symbol lookup_minimal_symbol_by_pc_section
 268   (CORE_ADDR pc_in,
 269    struct obj_section *section,
 270    lookup_msym_prefer prefer = lookup_msym_prefer::TEXT,
 271    bound_minimal_symbol *previous = nullptr);
 272
 273 /* Backward compatibility: search through the minimal symbol table
 274    for a matching PC (no section given).
 275
 276    This is a wrapper that calls lookup_minimal_symbol_by_pc_section
 277    with a NULL section argument.  */
 278
 279 struct bound_minimal_symbol lookup_minimal_symbol_by_pc (CORE_ADDR);
 280
 281 /* Iterate over all the minimal symbols in the objfile OBJF which
 282    match NAME.  Both the ordinary and demangled names of each symbol
 283    are considered.  The caller is responsible for canonicalizing NAME,
 284    should that need to be done.
 285
 286    For each matching symbol, CALLBACK is called with the symbol.  */
 287
 288 void iterate_over_minimal_symbols
 289     (struct objfile *objf, const lookup_name_info &name,
 290      gdb::function_view<bool (struct minimal_symbol *)> callback);
 291
 292 /* Compute the upper bound of MINSYM.  The upper bound is the last
 293    address thought to be part of the symbol.  If the symbol has a
 294    size, it is used.  Otherwise use the lesser of the next minimal
 295    symbol in the same section, or the end of the section, as the end
 296    of the function.  */
 297
 298 CORE_ADDR minimal_symbol_upper_bound (struct bound_minimal_symbol minsym);
 299
 300 /* Return the type of MSYMBOL, a minimal symbol of OBJFILE.  If
 301    ADDRESS_P is not NULL, set it to the MSYMBOL's resolved
 302    address.  */
 303
 304 type *find_minsym_type_and_address (minimal_symbol *msymbol, objfile *objf,
 305                                     CORE_ADDR *address_p);
 306
 307 #endif /* MINSYMS_H */