gdb/minsyms.h

   1 /* Minimal symbol table definitions for GDB.
   2
   3    Copyright (C) 2011-2020 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      COPY_NAME - if true, the minsym code must make a copy of NAME.  If
  92      false, then NAME must be NUL-terminated, and must have a lifetime
  93      that is at least as long as OBJFILE's lifetime.
  94      ADDRESS - the address of the symbol
  95      MS_TYPE - the type of the symbol
  96      SECTION - the symbol's section
  97   */
  98
  99   struct minimal_symbol *record_full (gdb::string_view name,
 100                                       bool copy_name,
 101                                       CORE_ADDR address,
 102                                       enum minimal_symbol_type ms_type,
 103                                       int section);
 104
 105   /* Like record_full, but:
 106      - computes the length of NAME
 107      - passes COPY_NAME = true,
 108      - and passes a default SECTION, depending on the type
 109
 110      This variant does not return the new symbol.  */
 111
 112   void record (const char *name, CORE_ADDR address,
 113                enum minimal_symbol_type ms_type);
 114
 115   /* Like record_full, but:
 116      - computes the length of NAME
 117      - passes COPY_NAME = true.
 118
 119      This variant does not return the new symbol.  */
 120
 121   void record_with_info (const char *name, CORE_ADDR address,
 122                          enum minimal_symbol_type ms_type,
 123                          int section)
 124   {
 125     record_full (name, true, address, ms_type, section);
 126   }
 127
 128  private:
 129
 130   DISABLE_COPY_AND_ASSIGN (minimal_symbol_reader);
 131
 132   struct objfile *m_objfile;
 133
 134   /* Bunch currently being filled up.
 135      The next field points to chain of filled bunches.  */
 136
 137   struct msym_bunch *m_msym_bunch;
 138
 139   /* Number of slots filled in current bunch.  */
 140
 141   int m_msym_bunch_index;
 142
 143   /* Total number of minimal symbols recorded so far for the
 144      objfile.  */
 145
 146   int m_msym_count;
 147 };
 148
 149 \f
 150
 151 /* Return whether MSYMBOL is a function/method.  If FUNC_ADDRESS_P is
 152    non-NULL, and the MSYMBOL is a function, then *FUNC_ADDRESS_P is
 153    set to the function's address, already resolved if MINSYM points to
 154    a function descriptor.  */
 155
 156 bool msymbol_is_function (struct objfile *objfile,
 157                           minimal_symbol *minsym,
 158                           CORE_ADDR *func_address_p = NULL);
 159
 160 /* Compute a hash code for the string argument.  Unlike htab_hash_string,
 161    this is a case-insensitive hash to support "set case-sensitive off".  */
 162
 163 unsigned int msymbol_hash (const char *);
 164
 165 /* Like msymbol_hash, but compute a hash code that is compatible with
 166    strcmp_iw.  */
 167
 168 unsigned int msymbol_hash_iw (const char *);
 169
 170 /* Compute the next hash value from previous HASH and the character C.  This
 171    is only a GDB in-memory computed value with no external files compatibility
 172    requirements.  */
 173
 174 #define SYMBOL_HASH_NEXT(hash, c)                       \
 175   ((hash) * 67 + TOLOWER ((unsigned char) (c)) - 113)
 176
 177 \f
 178
 179 /* Look through all the current minimal symbol tables and find the
 180    first minimal symbol that matches NAME.  If OBJF is non-NULL, limit
 181    the search to that objfile.  If SFILE is non-NULL, the only
 182    file-scope symbols considered will be from that source file (global
 183    symbols are still preferred).  Returns a bound minimal symbol that
 184    matches, or an empty bound minimal symbol if no match is found.  */
 185
 186 struct bound_minimal_symbol lookup_minimal_symbol (const char *,
 187                                                    const char *,
 188                                                    struct objfile *);
 189
 190 /* Like lookup_minimal_symbol, but searches all files and
 191    objfiles.  */
 192
 193 struct bound_minimal_symbol lookup_bound_minimal_symbol (const char *);
 194
 195 /* Look through all the current minimal symbol tables and find the
 196    first minimal symbol that matches NAME and has text type.  If OBJF
 197    is non-NULL, limit the search to that objfile.  Returns a bound
 198    minimal symbol that matches, or an "empty" bound minimal symbol
 199    otherwise.
 200
 201    This function only searches the mangled (linkage) names.  */
 202
 203 struct bound_minimal_symbol lookup_minimal_symbol_text (const char *,
 204                                                         struct objfile *);
 205
 206 /* Look through the minimal symbols in OBJF (and its separate debug
 207    objfiles) for a global (not file-local) minsym whose linkage name
 208    is NAME.  This is somewhat similar to lookup_minimal_symbol_text,
 209    only data symbols (not text symbols) are considered, and a non-NULL
 210    objfile is not accepted.  Returns a bound minimal symbol that
 211    matches, or an "empty" bound minimal symbol otherwise.  */
 212
 213 extern struct bound_minimal_symbol lookup_minimal_symbol_linkage
 214   (const char *name, struct objfile *objf)
 215   ATTRIBUTE_NONNULL (1) ATTRIBUTE_NONNULL (2);
 216
 217 /* Look through all the current minimal symbol tables and find the
 218    first minimal symbol that matches NAME and PC.  If OBJF is non-NULL,
 219    limit the search to that objfile.  Returns a pointer to the minimal
 220    symbol that matches, or NULL if no match is found.  */
 221
 222 struct minimal_symbol *lookup_minimal_symbol_by_pc_name
 223     (CORE_ADDR, const char *, struct objfile *);
 224
 225 enum class lookup_msym_prefer
 226 {
 227   /* Prefer mst_text symbols.  */
 228   TEXT,
 229
 230   /* Prefer mst_solib_trampoline symbols when there are text and
 231      trampoline symbols at the same address.  Otherwise prefer
 232      mst_text symbols.  */
 233   TRAMPOLINE,
 234
 235   /* Prefer mst_text_gnu_ifunc symbols when there are text and ifunc
 236      symbols at the same address.  Otherwise prefer mst_text
 237      symbols.  */
 238   GNU_IFUNC,
 239 };
 240
 241 /* Search through the minimal symbol table for each objfile and find
 242    the symbol whose address is the largest address that is still less
 243    than or equal to PC_IN, and which matches SECTION.  A matching symbol
 244    must either be zero sized and have address PC_IN, or PC_IN must fall
 245    within the range of addresses covered by the matching symbol.
 246
 247    If SECTION is NULL, this uses the result of find_pc_section
 248    instead.
 249
 250    The result has a non-NULL 'minsym' member if such a symbol is
 251    found, or NULL if PC is not in a suitable range.
 252
 253    See definition of lookup_msym_prefer for description of PREFER.  By
 254    default mst_text symbols are preferred.
 255
 256    If the PREVIOUS pointer is non-NULL, and no matching symbol is found,
 257    then the contents will be set to reference the closest symbol before
 258    PC_IN.  */
 259
 260 struct bound_minimal_symbol lookup_minimal_symbol_by_pc_section
 261   (CORE_ADDR pc_in,
 262    struct obj_section *section,
 263    lookup_msym_prefer prefer = lookup_msym_prefer::TEXT,
 264    bound_minimal_symbol *previous = nullptr);
 265
 266 /* Backward compatibility: search through the minimal symbol table
 267    for a matching PC (no section given).
 268
 269    This is a wrapper that calls lookup_minimal_symbol_by_pc_section
 270    with a NULL section argument.  */
 271
 272 struct bound_minimal_symbol lookup_minimal_symbol_by_pc (CORE_ADDR);
 273
 274 /* Iterate over all the minimal symbols in the objfile OBJF which
 275    match NAME.  Both the ordinary and demangled names of each symbol
 276    are considered.  The caller is responsible for canonicalizing NAME,
 277    should that need to be done.
 278
 279    For each matching symbol, CALLBACK is called with the symbol.  */
 280
 281 void iterate_over_minimal_symbols
 282     (struct objfile *objf, const lookup_name_info &name,
 283      gdb::function_view<bool (struct minimal_symbol *)> callback);
 284
 285 /* Compute the upper bound of MINSYM.  The upper bound is the last
 286    address thought to be part of the symbol.  If the symbol has a
 287    size, it is used.  Otherwise use the lesser of the next minimal
 288    symbol in the same section, or the end of the section, as the end
 289    of the function.  */
 290
 291 CORE_ADDR minimal_symbol_upper_bound (struct bound_minimal_symbol minsym);
 292
 293 /* Return the type of MSYMBOL, a minimal symbol of OBJFILE.  If
 294    ADDRESS_P is not NULL, set it to the MSYMBOL's resolved
 295    address.  */
 296
 297 type *find_minsym_type_and_address (minimal_symbol *msymbol, objfile *objf,
 298                                     CORE_ADDR *address_p);
 299
 300 #endif /* MINSYMS_H */