gdb/probe.h

   1 /* Generic SDT probe support for GDB.
   2
   3    Copyright (C) 2012-2017 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 #if !defined (PROBE_H)
  21 #define PROBE_H 1
  22
  23 struct event_location;
  24
  25 #include "gdb_vecs.h"
  26
  27 /* Definition of a vector of probes.  */
  28
  29 typedef struct probe *probe_p;
  30 DEF_VEC_P (probe_p);
  31
  32 struct linespec_result;
  33
  34 /* Structure useful for passing the header names in the method
  35    `gen_ui_out_table_header'.  */
  36
  37 struct info_probe_column
  38   {
  39     /* The internal name of the field.  This string cannot be capitalized nor
  40        localized, e.g., "extra_field".  */
  41
  42     const char *field_name;
  43
  44     /* The field name to be printed in the `info probes' command.  This
  45        string can be capitalized and localized, e.g., _("Extra Field").  */
  46     const char *print_name;
  47   };
  48
  49 typedef struct info_probe_column info_probe_column_s;
  50 DEF_VEC_O (info_probe_column_s);
  51
  52 /* Operations associated with a probe.  */
  53
  54 struct probe_ops
  55   {
  56     /* Method responsible for verifying if LINESPECP is a valid linespec for
  57        a probe breakpoint.  It should return 1 if it is, or zero if it is not.
  58        It also should update LINESPECP in order to discard the breakpoint
  59        option associated with this linespec.  For example, if the option is
  60        `-probe', and the LINESPECP is `-probe abc', the function should
  61        return 1 and set LINESPECP to `abc'.  */
  62
  63     int (*is_linespec) (const char **linespecp);
  64
  65     /* Function that should fill PROBES with known probes from OBJFILE.  */
  66
  67     void (*get_probes) (std::vector<probe *> *probes, struct objfile *objfile);
  68
  69     /* Compute the probe's relocated address.  OBJFILE is the objfile
  70        in which the probe originated.  */
  71
  72     CORE_ADDR (*get_probe_address) (struct probe *probe,
  73                                     struct objfile *objfile);
  74
  75     /* Return the number of arguments of PROBE.  This function can
  76        throw an exception.  */
  77
  78     unsigned (*get_probe_argument_count) (struct probe *probe,
  79                                           struct frame_info *frame);
  80
  81     /* Return 1 if the probe interface can evaluate the arguments of probe
  82        PROBE, zero otherwise.  See the comments on
  83        sym_probe_fns:can_evaluate_probe_arguments for more details.  */
  84
  85     int (*can_evaluate_probe_arguments) (struct probe *probe);
  86
  87     /* Evaluate the Nth argument from the PROBE, returning a value
  88        corresponding to it.  The argument number is represented N.
  89        This function can throw an exception.  */
  90
  91     struct value *(*evaluate_probe_argument) (struct probe *probe,
  92                                               unsigned n,
  93                                               struct frame_info *frame);
  94
  95     /* Compile the Nth argument of the PROBE to an agent expression.
  96        The argument number is represented by N.  */
  97
  98     void (*compile_to_ax) (struct probe *probe, struct agent_expr *aexpr,
  99                            struct axs_value *axs_value, unsigned n);
 100
 101     /* Set the semaphore associated with the PROBE.  This function only makes
 102        sense if the probe has a concept of semaphore associated to a
 103        probe, otherwise it can be set to NULL.  */
 104
 105     void (*set_semaphore) (struct probe *probe, struct objfile *objfile,
 106                            struct gdbarch *gdbarch);
 107
 108     /* Clear the semaphore associated with the PROBE.  This function only
 109        makes sense if the probe has a concept of semaphore associated to
 110        a probe, otherwise it can be set to NULL.  */
 111
 112     void (*clear_semaphore) (struct probe *probe, struct objfile *objfile,
 113                              struct gdbarch *gdbarch);
 114
 115     /* Function called to destroy PROBE's specific data.  This function
 116        shall not free PROBE itself.  */
 117
 118     void (*destroy) (struct probe *probe);
 119
 120     /* Return a pointer to a name identifying the probe type.  This is
 121        the string that will be displayed in the "Type" column of the
 122        `info probes' command.  */
 123
 124     const char *(*type_name) (struct probe *probe);
 125
 126     /* Function responsible for providing the extra fields that will be
 127        printed in the `info probes' command.  It should fill HEADS
 128        with whatever extra fields it needs.  If the backend doesn't need
 129        to print extra fields, it can set this method to NULL.  */
 130
 131     void (*gen_info_probes_table_header) (VEC (info_probe_column_s) **heads);
 132
 133     /* Function that will fill VALUES with the values of the extra fields
 134        to be printed for PROBE.  If the backend implements the
 135        `gen_ui_out_table_header' method, then it should implement
 136        this method as well.  The backend should also guarantee that the
 137        order and the number of values in the vector is exactly the same
 138        as the order of the extra fields provided in the method
 139        `gen_ui_out_table_header'.  If a certain field is to be skipped
 140        when printing the information, you can push a NULL value in that
 141        position in the vector.  */
 142
 143     void (*gen_info_probes_table_values) (struct probe *probe,
 144                                           VEC (const_char_ptr) **values);
 145
 146     /* Enable a probe.  The semantics of "enabling" a probe depend on
 147        the specific backend and the field can be NULL in case enabling
 148        probes is not supported.  This function can throw an
 149        exception.  */
 150
 151     void (*enable_probe) (struct probe *probe);
 152
 153     /* Disable a probe.  The semantics of "disabling" a probe depend
 154        on the specific backend and the field can be NULL in case
 155        disabling probes is not supported.  This function can throw an
 156        exception.  */
 157
 158     void (*disable_probe) (struct probe *probe);
 159   };
 160
 161 /* Definition of a vector of probe_ops.  */
 162
 163 extern std::vector<const probe_ops *> all_probe_ops;
 164
 165 /* The probe_ops associated with the generic probe.  */
 166
 167 extern const struct probe_ops probe_ops_any;
 168
 169 /* Helper function that, given KEYWORDS, iterate over it trying to match
 170    each keyword with LINESPECP.  If it succeeds, it updates the LINESPECP
 171    pointer and returns 1.  Otherwise, nothing is done to LINESPECP and zero
 172    is returned.  */
 173
 174 extern int probe_is_linespec_by_keyword (const char **linespecp,
 175                                          const char *const *keywords);
 176
 177 /* Return specific PROBE_OPS * matching *LINESPECP and possibly updating
 178    *LINESPECP to skip its "-probe-type " prefix.  Return &probe_ops_any if
 179    *LINESPECP matches "-probe ", that is any unspecific probe.  Return NULL if
 180    *LINESPECP is not identified as any known probe type, *LINESPECP is not
 181    modified in such case.  */
 182
 183 extern const struct probe_ops *probe_linespec_to_ops (const char **linespecp);
 184
 185 /* The probe itself.  The struct contains generic information about the
 186    probe, and then some specific information which should be stored in
 187    the `probe_info' field.  */
 188
 189 struct probe
 190   {
 191     /* The operations associated with this probe.  */
 192     const struct probe_ops *pops;
 193
 194     /* The probe's architecture.  */
 195     struct gdbarch *arch;
 196
 197     /* The name of the probe.  */
 198     const char *name;
 199
 200     /* The provider of the probe.  It generally defaults to the name of
 201        the objfile which contains the probe.  */
 202     const char *provider;
 203
 204     /* The address where the probe is inserted, relative to
 205        SECT_OFF_TEXT.  */
 206     CORE_ADDR address;
 207   };
 208
 209 /* A bound probe holds a pointer to a probe and a pointer to the
 210    probe's defining objfile.  This is needed because probes are
 211    independent of the program space and thus require relocation at
 212    their point of use.  */
 213
 214 struct bound_probe
 215 {
 216   /* Create an empty bound_probe object.  */
 217
 218   bound_probe ()
 219   {}
 220
 221   /* Create and initialize a bound_probe object using PROBE and OBJFILE.  */
 222
 223   bound_probe (struct probe *probe_, struct objfile *objfile_)
 224   : probe (probe_), objfile (objfile_)
 225   {}
 226
 227   /* The probe.  */
 228
 229   struct probe *probe = NULL;
 230
 231   /* The objfile in which the probe originated.  */
 232
 233   struct objfile *objfile = NULL;
 234 };
 235
 236 /* A helper for linespec that decodes a probe specification.  It
 237    returns a std::vector<symtab_and_line> object and updates LOC or
 238    throws an error.  */
 239
 240 extern std::vector<symtab_and_line> parse_probes
 241   (const struct event_location *loc,
 242    struct program_space *pspace,
 243    struct linespec_result *canon);
 244
 245 /* Helper function to register the proper probe_ops to a newly created probe.
 246    This function is mainly called from `sym_get_probes'.  */
 247
 248 extern void register_probe_ops (struct probe *probe);
 249
 250 /* Given a PC, find an associated probe.  If a probe is found, return
 251    it.  If no probe is found, return a bound probe whose fields are
 252    both NULL.  */
 253
 254 extern struct bound_probe find_probe_by_pc (CORE_ADDR pc);
 255
 256 /* Search OBJFILE for a probe with the given PROVIDER, NAME.  Return a
 257    VEC of all probes that were found.  If no matching probe is found,
 258    return NULL.  The caller must free the VEC.  */
 259
 260 extern VEC (probe_p) *find_probes_in_objfile (struct objfile *objfile,
 261                                               const char *provider,
 262                                               const char *name);
 263
 264 /* Generate a `info probes' command output for probe_ops represented by
 265    POPS.  If POPS is NULL it considers any probes types.  It is a helper
 266    function that can be used by the probe backends to print their
 267    `info probe TYPE'.  */
 268
 269 extern void info_probes_for_ops (const char *arg, int from_tty,
 270                                  const struct probe_ops *pops);
 271
 272 /* Return the `cmd_list_element' associated with the `info probes' command,
 273    or create a new one if it doesn't exist.  Helper function that serves the
 274    purpose of avoiding the case of a backend using the `cmd_list_element'
 275    associated with `info probes', without having it registered yet.  */
 276
 277 extern struct cmd_list_element **info_probes_cmdlist_get (void);
 278
 279 /* Compute the probe's relocated address.  OBJFILE is the objfile in
 280    which the probe originated.  */
 281
 282 extern CORE_ADDR get_probe_address (struct probe *probe,
 283                                     struct objfile *objfile);
 284
 285 /* Return the argument count of the specified probe.
 286
 287    This function can throw an exception.  */
 288
 289 extern unsigned get_probe_argument_count (struct probe *probe,
 290                                           struct frame_info *frame);
 291
 292 /* Return 1 if the probe interface associated with PROBE can evaluate
 293    arguments, zero otherwise.  See the comments on the definition of
 294    sym_probe_fns:can_evaluate_probe_arguments for more details.  */
 295
 296 extern int can_evaluate_probe_arguments (struct probe *probe);
 297
 298 /* Evaluate argument N of the specified probe.  N must be between 0
 299    inclusive and get_probe_argument_count exclusive.
 300
 301    This function can throw an exception.  */
 302
 303 extern struct value *evaluate_probe_argument (struct probe *probe,
 304                                               unsigned n,
 305                                               struct frame_info *frame);
 306
 307 /* A convenience function that finds a probe at the PC in FRAME and
 308    evaluates argument N, with 0 <= N < number_of_args.  If there is no
 309    probe at that location, or if the probe does not have enough arguments,
 310    this returns NULL.  */
 311
 312 extern struct value *probe_safe_evaluate_at_pc (struct frame_info *frame,
 313                                                 unsigned n);
 314
 315 #endif /* !defined (PROBE_H) */