gdb/minsyms.h

   1 /* Minimal symbol table definitions for GDB.
   2
   3    Copyright (C) 2011-2024 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 program_space;
  24 struct type;
  25
  26 /* Several lookup functions return both a minimal symbol and the
  27    objfile in which it is found.  This structure is used in these
  28    cases.  */
  29
  30 struct bound_minimal_symbol
  31 {
  32   bound_minimal_symbol (struct minimal_symbol *msym, struct objfile *objf)
  33     : minsym (msym),
  34       objfile (objf)
  35   {
  36   }
  37
  38   bound_minimal_symbol () = default;
  39
  40   /* Return the address of the minimal symbol in the context of the objfile.  */
  41
  42   CORE_ADDR value_address () const
  43   {
  44     return this->minsym->value_address (this->objfile);
  45   }
  46
  47   /* The minimal symbol that was found, or NULL if no minimal symbol
  48      was found.  */
  49
  50   struct minimal_symbol *minsym = nullptr;
  51
  52   /* If MINSYM is not NULL, then this is the objfile in which the
  53      symbol is defined.  */
  54
  55   struct objfile *objfile = nullptr;
  56
  57   /* Return the obj_section from OBJFILE for MINSYM.  */
  58
  59   struct obj_section *obj_section () const
  60   {
  61     return minsym->obj_section (objfile);
  62   }
  63 };
  64
  65 /* This header declares most of the API for dealing with minimal
  66    symbols and minimal symbol tables.  A few things are declared
  67    elsewhere; see below.
  68
  69    A minimal symbol is a symbol for which there is no direct debug
  70    information.  For example, for an ELF binary, minimal symbols are
  71    created from the ELF symbol table.
  72
  73    For the definition of the minimal symbol structure, see struct
  74    minimal_symbol in symtab.h.
  75
  76    Minimal symbols are stored in tables attached to an objfile; see
  77    objfiles.h for details.  Code should generally treat these tables
  78    as opaque and use functions provided by minsyms.c to inspect them.
  79 */
  80
  81 struct msym_bunch;
  82
  83 /* An RAII-based object that is used to record minimal symbols while
  84    they are being read.  */
  85 class minimal_symbol_reader
  86 {
  87  public:
  88
  89   /* Prepare to start collecting minimal symbols.  This should be
  90      called by a symbol reader to initialize the minimal symbol
  91      module.  */
  92
  93   explicit minimal_symbol_reader (struct objfile *);
  94
  95   ~minimal_symbol_reader ();
  96
  97   /* Install the minimal symbols that have been collected into the
  98      given objfile.  */
  99
 100   void install ();
 101
 102   /* Record a new minimal symbol.  This is the "full" entry point;
 103      simpler convenience entry points are also provided below.
 104
 105      This returns a new minimal symbol.  It is ok to modify the returned
 106      minimal symbol (though generally not necessary).  It is not ok,
 107      though, to stash the pointer anywhere; as minimal symbols may be
 108      moved after creation.  The memory for the returned minimal symbol
 109      is still owned by the minsyms.c code, and should not be freed.
 110
 111      Arguments are:
 112
 113      NAME - the symbol's name
 114      COPY_NAME - if true, the minsym code must make a copy of NAME.  If
 115      false, then NAME must be NUL-terminated, and must have a lifetime
 116      that is at least as long as OBJFILE's lifetime.
 117      ADDRESS - the address of the symbol
 118      MS_TYPE - the type of the symbol
 119      SECTION - the symbol's section
 120   */
 121
 122   struct minimal_symbol *record_full (std::string_view name,
 123                                       bool copy_name,
 124                                       unrelocated_addr address,
 125                                       enum minimal_symbol_type ms_type,
 126                                       int section);
 127
 128   /* Like record_full, but:
 129      - computes the length of NAME
 130      - passes COPY_NAME = true,
 131      - and passes a default SECTION, depending on the type
 132
 133      This variant does not return the new symbol.  */
 134
 135   void record (const char *name, unrelocated_addr address,
 136                enum minimal_symbol_type ms_type);
 137
 138   /* Like record_full, but:
 139      - computes the length of NAME
 140      - passes COPY_NAME = true.
 141
 142      This variant does not return the new symbol.  */
 143
 144   void record_with_info (const char *name, unrelocated_addr address,
 145                          enum minimal_symbol_type ms_type,
 146                          int section)
 147   {
 148     record_full (name, true, address, ms_type, section);
 149   }
 150
 151  private:
 152
 153   DISABLE_COPY_AND_ASSIGN (minimal_symbol_reader);
 154
 155   struct objfile *m_objfile;
 156
 157   /* Bunch currently being filled up.
 158      The next field points to chain of filled bunches.  */
 159
 160   struct msym_bunch *m_msym_bunch;
 161
 162   /* Number of slots filled in current bunch.  */
 163
 164   int m_msym_bunch_index;
 165
 166   /* Total number of minimal symbols recorded so far for the
 167      objfile.  */
 168
 169   int m_msym_count;
 170 };
 171
 172 \f
 173
 174 /* Return whether MSYMBOL is a function/method.  If FUNC_ADDRESS_P is
 175    non-NULL, and the MSYMBOL is a function, then *FUNC_ADDRESS_P is
 176    set to the function's address, already resolved if MINSYM points to
 177    a function descriptor.  */
 178
 179 bool msymbol_is_function (struct objfile *objfile,
 180                           minimal_symbol *minsym,
 181                           CORE_ADDR *func_address_p = NULL);
 182
 183 /* Compute a hash code for the string argument.  Unlike htab_hash_string,
 184    this is a case-insensitive hash to support "set case-sensitive off".  */
 185
 186 unsigned int msymbol_hash (const char *);
 187
 188 /* Like msymbol_hash, but compute a hash code that is compatible with
 189    strcmp_iw.  */
 190
 191 unsigned int msymbol_hash_iw (const char *);
 192
 193 /* Compute the next hash value from previous HASH and the character C.  This
 194    is only a GDB in-memory computed value with no external files compatibility
 195    requirements.  */
 196
 197 #define SYMBOL_HASH_NEXT(hash, c)                       \
 198   ((hash) * 67 + TOLOWER ((unsigned char) (c)) - 113)
 199
 200 \f
 201
 202 /* Look through all the current minimal symbol tables and find the
 203    first minimal symbol that matches NAME.  If OBJF is non-NULL, limit
 204    the search to that objfile.  If SFILE is non-NULL, the only
 205    file-scope symbols considered will be from that source file (global
 206    symbols are still preferred).  Returns a bound minimal symbol that
 207    matches, or an empty bound minimal symbol if no match is found.  */
 208
 209 bound_minimal_symbol lookup_minimal_symbol (program_space *pspace,
 210                                             const char *name,
 211                                             objfile *obj = nullptr,
 212                                             const char *sfile = nullptr);
 213
 214 /* Look through all the minimal symbol tables in PSPACE and find the
 215    first minimal symbol that matches NAME and has text type.  If OBJF
 216    is non-NULL, limit the search to that objfile.  Returns a bound
 217    minimal symbol that matches, or an "empty" bound minimal symbol
 218    otherwise.
 219
 220    This function only searches the mangled (linkage) names.  */
 221
 222 bound_minimal_symbol lookup_minimal_symbol_text (program_space *pspace,
 223                                                  const char *name,
 224                                                  objfile *objf);
 225
 226 /* Look through the minimal symbols in OBJF (and its separate debug
 227    objfiles) for a global (not file-local) minsym whose linkage name
 228    is NAME.  This is somewhat similar to lookup_minimal_symbol_text,
 229    only data symbols (not text symbols) are considered, and a non-NULL
 230    objfile is not accepted.  The boolean argument allows matching the
 231    static types of data symbols also.  Returns a bound minimal symbol
 232    that matches, or an "empty" bound minimal symbol otherwise.  */
 233
 234 extern bound_minimal_symbol lookup_minimal_symbol_linkage
 235   (const char *name, struct objfile *objf, bool match_static_type)
 236   ATTRIBUTE_NONNULL (1) ATTRIBUTE_NONNULL (2);
 237
 238 /* A variant of lookup_minimal_symbol_linkage that iterates over all
 239    objfiles of PSPACE.  If ONLY_MAIN is true, then only an objfile with
 240    OBJF_MAINLINE will be considered.  */
 241
 242 extern bound_minimal_symbol lookup_minimal_symbol_linkage
 243   (program_space *pspace, const char *name, bool only_main)
 244   ATTRIBUTE_NONNULL (1);
 245
 246 /* Look through all the current minimal symbol tables and find the
 247    first minimal symbol that matches NAME and PC.  If OBJF is non-NULL,
 248    limit the search to that objfile.  Returns a pointer to the minimal
 249    symbol that matches, or NULL if no match is found.  */
 250
 251 struct minimal_symbol *lookup_minimal_symbol_by_pc_name
 252     (CORE_ADDR, const char *, struct objfile *);
 253
 254 enum class lookup_msym_prefer
 255 {
 256   /* Prefer mst_text symbols.  */
 257   TEXT,
 258
 259   /* Prefer mst_solib_trampoline symbols when there are text and
 260      trampoline symbols at the same address.  Otherwise prefer
 261      mst_text symbols.  */
 262   TRAMPOLINE,
 263
 264   /* Prefer mst_text_gnu_ifunc symbols when there are text and ifunc
 265      symbols at the same address.  Otherwise prefer mst_text
 266      symbols.  */
 267   GNU_IFUNC,
 268 };
 269
 270 /* Search through the minimal symbol table for each objfile and find
 271    the symbol whose address is the largest address that is still less
 272    than or equal to PC_IN, and which matches SECTION.  A matching symbol
 273    must either be zero sized and have address PC_IN, or PC_IN must fall
 274    within the range of addresses covered by the matching symbol.
 275
 276    If SECTION is NULL, this uses the result of find_pc_section
 277    instead.
 278
 279    The result has a non-NULL 'minsym' member if such a symbol is
 280    found, or NULL if PC is not in a suitable range.
 281
 282    See definition of lookup_msym_prefer for description of PREFER.  By
 283    default mst_text symbols are preferred.
 284
 285    If the PREVIOUS pointer is non-NULL, and no matching symbol is found,
 286    then the contents will be set to reference the closest symbol before
 287    PC_IN.  */
 288
 289 bound_minimal_symbol lookup_minimal_symbol_by_pc_section
 290   (CORE_ADDR pc_in,
 291    struct obj_section *section,
 292    lookup_msym_prefer prefer = lookup_msym_prefer::TEXT,
 293    bound_minimal_symbol *previous = nullptr);
 294
 295 /* Backward compatibility: search through the minimal symbol table
 296    for a matching PC (no section given).
 297
 298    This is a wrapper that calls lookup_minimal_symbol_by_pc_section
 299    with a NULL section argument.  */
 300
 301 bound_minimal_symbol lookup_minimal_symbol_by_pc (CORE_ADDR);
 302
 303 /* Iterate over all the minimal symbols in the objfile OBJF which
 304    match NAME.  Both the ordinary and demangled names of each symbol
 305    are considered.  The caller is responsible for canonicalizing NAME,
 306    should that need to be done.
 307
 308    For each matching symbol, CALLBACK is called with the symbol.  */
 309
 310 void iterate_over_minimal_symbols
 311     (struct objfile *objf, const lookup_name_info &name,
 312      gdb::function_view<bool (struct minimal_symbol *)> callback);
 313
 314 /* Compute the upper bound of MINSYM.  The upper bound is the last
 315    address thought to be part of the symbol.  If the symbol has a
 316    size, it is used.  Otherwise use the lesser of the next minimal
 317    symbol in the same section, or the end of the section, as the end
 318    of the function.  */
 319
 320 CORE_ADDR minimal_symbol_upper_bound (bound_minimal_symbol minsym);
 321
 322 /* Return the type of MSYMBOL, a minimal symbol of OBJFILE.  If
 323    ADDRESS_P is not NULL, set it to the MSYMBOL's resolved
 324    address.  */
 325
 326 type *find_minsym_type_and_address (minimal_symbol *msymbol, objfile *objf,
 327                                     CORE_ADDR *address_p);
 328
 329 #endif /* MINSYMS_H */