gdb/minsyms.h

   1 /* Minimal symbol table definitions for GDB.
   2
   3    Copyright (C) 2011-2019 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 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
  42 /* This header declares most of the API for dealing with minimal
  43    symbols and minimal symbol tables.  A few things are declared
  44    elsewhere; see below.
  45
  46    A minimal symbol is a symbol for which there is no direct debug
  47    information.  For example, for an ELF binary, minimal symbols are
  48    created from the ELF symbol table.
  49
  50    For the definition of the minimal symbol structure, see struct
  51    minimal_symbol in symtab.h.
  52
  53    Minimal symbols are stored in tables attached to an objfile; see
  54    objfiles.h for details.  Code should generally treat these tables
  55    as opaque and use functions provided by minsyms.c to inspect them.
  56 */
  57
  58 struct msym_bunch;
  59
  60 /* An RAII-based object that is used to record minimal symbols while
  61    they are being read.  */
  62 class minimal_symbol_reader
  63 {
  64  public:
  65
  66   /* Prepare to start collecting minimal symbols.  This should be
  67      called by a symbol reader to initialize the minimal symbol
  68      module.  */
  69
  70   explicit minimal_symbol_reader (struct objfile *);
  71
  72   ~minimal_symbol_reader ();
  73
  74   /* Install the minimal symbols that have been collected into the
  75      given objfile.  */
  76
  77   void install ();
  78
  79   /* Record a new minimal symbol.  This is the "full" entry point;
  80      simpler convenience entry points are also provided below.
  81
  82      This returns a new minimal symbol.  It is ok to modify the returned
  83      minimal symbol (though generally not necessary).  It is not ok,
  84      though, to stash the pointer anywhere; as minimal symbols may be
  85      moved after creation.  The memory for the returned minimal symbol
  86      is still owned by the minsyms.c code, and should not be freed.
  87
  88      Arguments are:
  89
  90      NAME - the symbol's name
  91      NAME_LEN - the length of the name
  92      COPY_NAME - if true, the minsym code must make a copy of NAME.  If
  93      false, then NAME must be NUL-terminated, and must have a lifetime
  94      that is at least as long as OBJFILE's lifetime.
  95      ADDRESS - the address of the symbol
  96      MS_TYPE - the type of the symbol
  97      SECTION - the symbol's section
  98   */
  99
 100   struct minimal_symbol *record_full (const char *name,
 101                                       int name_len,
 102                                       bool copy_name,
 103                                       CORE_ADDR address,
 104                                       enum minimal_symbol_type ms_type,
 105                                       int section);
 106
 107   /* Like record_full, but:
 108      - uses strlen to compute NAME_LEN,
 109      - passes COPY_NAME = true,
 110      - and passes a default SECTION, depending on the type
 111
 112      This variant does not return the new symbol.  */
 113
 114   void record (const char *name, CORE_ADDR address,
 115                enum minimal_symbol_type ms_type);
 116
 117   /* Like record_full, but:
 118      - uses strlen to compute NAME_LEN,
 119      - passes COPY_NAME = true.
 120
 121      This variant does not return the new symbol.  */
 122
 123   void record_with_info (const char *name, CORE_ADDR address,
 124                          enum minimal_symbol_type ms_type,
 125                          int section)
 126   {
 127     record_full (name, strlen (name), true, address, ms_type, section);
 128   }
 129
 130  private:
 131
 132   DISABLE_COPY_AND_ASSIGN (minimal_symbol_reader);
 133
 134   struct objfile *m_objfile;
 135
 136   /* Bunch currently being filled up.
 137      The next field points to chain of filled bunches.  */
 138
 139   struct msym_bunch *m_msym_bunch;
 140
 141   /* Number of slots filled in current bunch.  */
 142
 143   int m_msym_bunch_index;
 144
 145   /* Total number of minimal symbols recorded so far for the
 146      objfile.  */
 147
 148   int m_msym_count;
 149 };
 150
 151 /* Create the terminating entry of OBJFILE's minimal symbol table.
 152    If OBJFILE->msymbols is zero, allocate a single entry from
 153    OBJFILE->objfile_obstack; otherwise, just initialize
 154    OBJFILE->msymbols[OBJFILE->minimal_symbol_count].  */
 155
 156 void terminate_minimal_symbol_table (struct objfile *objfile);
 157
 158 \f
 159
 160 /* Return whether MSYMBOL is a function/method.  If FUNC_ADDRESS_P is
 161    non-NULL, and the MSYMBOL is a function, then *FUNC_ADDRESS_P is
 162    set to the function's address, already resolved if MINSYM points to
 163    a function descriptor.  */
 164
 165 bool msymbol_is_function (struct objfile *objfile,
 166                           minimal_symbol *minsym,
 167                           CORE_ADDR *func_address_p = NULL);
 168
 169 /* Compute a hash code for the string argument.  */
 170
 171 unsigned int msymbol_hash (const char *);
 172
 173 /* Like msymbol_hash, but compute a hash code that is compatible with
 174    strcmp_iw.  */
 175
 176 unsigned int msymbol_hash_iw (const char *);
 177
 178 /* Compute the next hash value from previous HASH and the character C.  This
 179    is only a GDB in-memory computed value with no external files compatibility
 180    requirements.  */
 181
 182 #define SYMBOL_HASH_NEXT(hash, c)                       \
 183   ((hash) * 67 + TOLOWER ((unsigned char) (c)) - 113)
 184
 185 \f
 186
 187 /* Look through all the current minimal symbol tables and find the
 188    first minimal symbol that matches NAME.  If OBJF is non-NULL, limit
 189    the search to that objfile.  If SFILE is non-NULL, the only
 190    file-scope symbols considered will be from that source file (global
 191    symbols are still preferred).  Returns a bound minimal symbol that
 192    matches, or an empty bound minimal symbol if no match is found.  */
 193
 194 struct bound_minimal_symbol lookup_minimal_symbol (const char *,
 195                                                    const char *,
 196                                                    struct objfile *);
 197
 198 /* Like lookup_minimal_symbol, but searches all files and
 199    objfiles.  */
 200
 201 struct bound_minimal_symbol lookup_bound_minimal_symbol (const char *);
 202
 203 /* Look through all the current minimal symbol tables and find the
 204    first minimal symbol that matches NAME and has text type.  If OBJF
 205    is non-NULL, limit the search to that objfile.  Returns a bound
 206    minimal symbol that matches, or an "empty" bound minimal symbol
 207    otherwise.
 208
 209    This function only searches the mangled (linkage) names.  */
 210
 211 struct bound_minimal_symbol lookup_minimal_symbol_text (const char *,
 212                                                         struct objfile *);
 213
 214 /* Look through all the current minimal symbol tables and find the
 215    first minimal symbol that matches NAME and is a solib trampoline.
 216    If OBJF is non-NULL, limit the search to that objfile.  Returns a
 217    pointer to the minimal symbol that matches, or NULL if no match is
 218    found.
 219
 220    This function only searches the mangled (linkage) names.  */
 221
 222 struct bound_minimal_symbol lookup_minimal_symbol_solib_trampoline
 223     (const char *,
 224      struct objfile *);
 225
 226 /* Look through all the current minimal symbol tables and find the
 227    first minimal symbol that matches NAME and PC.  If OBJF is non-NULL,
 228    limit the search to that objfile.  Returns a pointer to the minimal
 229    symbol that matches, or NULL if no match is found.  */
 230
 231 struct minimal_symbol *lookup_minimal_symbol_by_pc_name
 232     (CORE_ADDR, const char *, struct objfile *);
 233
 234 enum class lookup_msym_prefer
 235 {
 236   /* Prefer mst_text symbols.  */
 237   TEXT,
 238
 239   /* Prefer mst_solib_trampoline symbols when there are text and
 240      trampoline symbols at the same address.  Otherwise prefer
 241      mst_text symbols.  */
 242   TRAMPOLINE,
 243
 244   /* Prefer mst_text_gnu_ifunc symbols when there are text and ifunc
 245      symbols at the same address.  Otherwise prefer mst_text
 246      symbols.  */
 247   GNU_IFUNC,
 248 };
 249
 250 /* Search through the minimal symbol table for each objfile and find
 251    the symbol whose address is the largest address that is still less
 252    than or equal to PC, and which matches SECTION.
 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 struct bound_minimal_symbol lookup_minimal_symbol_by_pc_section
 264   (CORE_ADDR,
 265    struct obj_section *,
 266    lookup_msym_prefer prefer = lookup_msym_prefer::TEXT);
 267
 268 /* Backward compatibility: search through the minimal symbol table
 269    for a matching PC (no section given).
 270
 271    This is a wrapper that calls lookup_minimal_symbol_by_pc_section
 272    with a NULL section argument.  */
 273
 274 struct bound_minimal_symbol lookup_minimal_symbol_by_pc (CORE_ADDR);
 275
 276 /* Iterate over all the minimal symbols in the objfile OBJF which
 277    match NAME.  Both the ordinary and demangled names of each symbol
 278    are considered.  The caller is responsible for canonicalizing NAME,
 279    should that need to be done.
 280
 281    For each matching symbol, CALLBACK is called with the symbol.  */
 282
 283 void iterate_over_minimal_symbols
 284     (struct objfile *objf, const lookup_name_info &name,
 285      gdb::function_view<bool (struct minimal_symbol *)> callback);
 286
 287 /* Compute the upper bound of MINSYM.  The upper bound is the last
 288    address thought to be part of the symbol.  If the symbol has a
 289    size, it is used.  Otherwise use the lesser of the next minimal
 290    symbol in the same section, or the end of the section, as the end
 291    of the function.  */
 292
 293 CORE_ADDR minimal_symbol_upper_bound (struct bound_minimal_symbol minsym);
 294
 295 /* Return the type of MSYMBOL, a minimal symbol of OBJFILE.  If
 296    ADDRESS_P is not NULL, set it to the MSYMBOL's resolved
 297    address.  */
 298
 299 type *find_minsym_type_and_address (minimal_symbol *msymbol, objfile *objf,
 300                                     CORE_ADDR *address_p);
 301
 302 #endif /* MINSYMS_H */