gdb/minsyms.h

   1 /* Minimal symbol table definitions for GDB.
   2
   3    Copyright (C) 2011-2018 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   struct minimal_symbol *record_with_info (const char *name,
 122                                            CORE_ADDR address,
 123                                            enum minimal_symbol_type ms_type,
 124                                            int section)
 125   {
 126     return record_full (name, strlen (name), true, address, ms_type, section);
 127   }
 128
 129  private:
 130
 131   /* No need for these.  They are intentionally not defined anywhere.  */
 132   minimal_symbol_reader &operator=
 133     (const minimal_symbol_reader &);
 134   minimal_symbol_reader (const minimal_symbol_reader &);
 135
 136   struct objfile *m_objfile;
 137
 138   /* Bunch currently being filled up.
 139      The next field points to chain of filled bunches.  */
 140
 141   struct msym_bunch *m_msym_bunch;
 142
 143   /* Number of slots filled in current bunch.  */
 144
 145   int m_msym_bunch_index;
 146
 147   /* Total number of minimal symbols recorded so far for the
 148      objfile.  */
 149
 150   int m_msym_count;
 151 };
 152
 153 /* Create the terminating entry of OBJFILE's minimal symbol table.
 154    If OBJFILE->msymbols is zero, allocate a single entry from
 155    OBJFILE->objfile_obstack; otherwise, just initialize
 156    OBJFILE->msymbols[OBJFILE->minimal_symbol_count].  */
 157
 158 void terminate_minimal_symbol_table (struct objfile *objfile);
 159
 160 \f
 161
 162 /* Return whether MSYMBOL is a function/method.  If FUNC_ADDRESS_P is
 163    non-NULL, and the MSYMBOL is a function, then *FUNC_ADDRESS_P is
 164    set to the function's address, already resolved if MINSYM points to
 165    a function descriptor.  */
 166
 167 bool msymbol_is_function (struct objfile *objfile,
 168                           minimal_symbol *minsym,
 169                           CORE_ADDR *func_address_p = NULL);
 170
 171 /* Compute a hash code for the string argument.  */
 172
 173 unsigned int msymbol_hash (const char *);
 174
 175 /* Like msymbol_hash, but compute a hash code that is compatible with
 176    strcmp_iw.  */
 177
 178 unsigned int msymbol_hash_iw (const char *);
 179
 180 /* Compute the next hash value from previous HASH and the character C.  This
 181    is only a GDB in-memory computed value with no external files compatibility
 182    requirements.  */
 183
 184 #define SYMBOL_HASH_NEXT(hash, c)                       \
 185   ((hash) * 67 + TOLOWER ((unsigned char) (c)) - 113)
 186
 187 \f
 188
 189 /* Look through all the current minimal symbol tables and find the
 190    first minimal symbol that matches NAME.  If OBJF is non-NULL, limit
 191    the search to that objfile.  If SFILE is non-NULL, the only
 192    file-scope symbols considered will be from that source file (global
 193    symbols are still preferred).  Returns a bound minimal symbol that
 194    matches, or an empty bound minimal symbol if no match is found.  */
 195
 196 struct bound_minimal_symbol lookup_minimal_symbol (const char *,
 197                                                    const char *,
 198                                                    struct objfile *);
 199
 200 /* Like lookup_minimal_symbol, but searches all files and
 201    objfiles.  */
 202
 203 struct bound_minimal_symbol lookup_bound_minimal_symbol (const char *);
 204
 205 /* Look through all the current minimal symbol tables and find the
 206    first minimal symbol that matches NAME and has text type.  If OBJF
 207    is non-NULL, limit the search to that objfile.  Returns a bound
 208    minimal symbol that matches, or an "empty" bound minimal symbol
 209    otherwise.
 210
 211    This function only searches the mangled (linkage) names.  */
 212
 213 struct bound_minimal_symbol lookup_minimal_symbol_text (const char *,
 214                                                         struct objfile *);
 215
 216 /* Look through all the current minimal symbol tables and find the
 217    first minimal symbol that matches NAME and is a solib trampoline.
 218    If OBJF is non-NULL, limit the search to that objfile.  Returns a
 219    pointer to the minimal symbol that matches, or NULL if no match is
 220    found.
 221
 222    This function only searches the mangled (linkage) names.  */
 223
 224 struct bound_minimal_symbol lookup_minimal_symbol_solib_trampoline
 225     (const char *,
 226      struct objfile *);
 227
 228 /* Look through all the current minimal symbol tables and find the
 229    first minimal symbol that matches NAME and PC.  If OBJF is non-NULL,
 230    limit the search to that objfile.  Returns a pointer to the minimal
 231    symbol that matches, or NULL if no match is found.  */
 232
 233 struct minimal_symbol *lookup_minimal_symbol_by_pc_name
 234     (CORE_ADDR, const char *, struct objfile *);
 235
 236 enum class lookup_msym_prefer
 237 {
 238   /* Prefer mst_text symbols.  */
 239   TEXT,
 240
 241   /* Prefer mst_solib_trampoline symbols when there are text and
 242      trampoline symbols at the same address.  Otherwise prefer
 243      mst_text symbols.  */
 244   TRAMPOLINE,
 245
 246   /* Prefer mst_text_gnu_ifunc symbols when there are text and ifunc
 247      symbols at the same address.  Otherwise prefer mst_text
 248      symbols.  */
 249   GNU_IFUNC,
 250 };
 251
 252 /* Search through the minimal symbol table for each objfile and find
 253    the symbol whose address is the largest address that is still less
 254    than or equal to PC, and which matches SECTION.
 255
 256    If SECTION is NULL, this uses the result of find_pc_section
 257    instead.
 258
 259    The result has a non-NULL 'minsym' member if such a symbol is
 260    found, or NULL if PC is not in a suitable range.
 261
 262    See definition of lookup_msym_prefer for description of PREFER.  By
 263    default mst_text symbols are preferred.  */
 264
 265 struct bound_minimal_symbol lookup_minimal_symbol_by_pc_section
 266   (CORE_ADDR,
 267    struct obj_section *,
 268    lookup_msym_prefer prefer = lookup_msym_prefer::TEXT);
 269
 270 /* Backward compatibility: search through the minimal symbol table
 271    for a matching PC (no section given).
 272
 273    This is a wrapper that calls lookup_minimal_symbol_by_pc_section
 274    with a NULL section argument.  */
 275
 276 struct bound_minimal_symbol lookup_minimal_symbol_by_pc (CORE_ADDR);
 277
 278 /* Iterate over all the minimal symbols in the objfile OBJF which
 279    match NAME.  Both the ordinary and demangled names of each symbol
 280    are considered.  The caller is responsible for canonicalizing NAME,
 281    should that need to be done.
 282
 283    For each matching symbol, CALLBACK is called with the symbol.  */
 284
 285 void iterate_over_minimal_symbols
 286     (struct objfile *objf, const lookup_name_info &name,
 287      gdb::function_view<bool (struct minimal_symbol *)> callback);
 288
 289 /* Compute the upper bound of MINSYM.  The upper bound is the last
 290    address thought to be part of the symbol.  If the symbol has a
 291    size, it is used.  Otherwise use the lesser of the next minimal
 292    symbol in the same section, or the end of the section, as the end
 293    of the function.  */
 294
 295 CORE_ADDR minimal_symbol_upper_bound (struct bound_minimal_symbol minsym);
 296
 297 /* Return the type of MSYMBOL, a minimal symbol of OBJFILE.  If
 298    ADDRESS_P is not NULL, set it to the MSYMBOL's resolved
 299    address.  */
 300
 301 type *find_minsym_type_and_address (minimal_symbol *msymbol, objfile *objf,
 302                                     CORE_ADDR *address_p);
 303
 304 #endif /* MINSYMS_H */