gdb/probe.h

   1 /* Generic SDT probe support for GDB.
   2
   3    Copyright (C) 2012-2015 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 #include "gdb_vecs.h"
  24
  25 /* Definition of a vector of probes.  */
  26
  27 typedef struct probe *probe_p;
  28 DEF_VEC_P (probe_p);
  29
  30 struct linespec_result;
  31
  32 /* Structure useful for passing the header names in the method
  33    `gen_ui_out_table_header'.  */
  34
  35 struct info_probe_column
  36   {
  37     /* The internal name of the field.  This string cannot be capitalized nor
  38        localized, e.g., "extra_field".  */
  39
  40     const char *field_name;
  41
  42     /* The field name to be printed in the `info probes' command.  This
  43        string can be capitalized and localized, e.g., _("Extra Field").  */
  44     const char *print_name;
  45   };
  46
  47 typedef struct info_probe_column info_probe_column_s;
  48 DEF_VEC_O (info_probe_column_s);
  49
  50 /* Operations associated with a probe.  */
  51
  52 struct probe_ops
  53   {
  54     /* Method responsible for verifying if LINESPECP is a valid linespec for
  55        a probe breakpoint.  It should return 1 if it is, or zero if it is not.
  56        It also should update LINESPECP in order to discard the breakpoint
  57        option associated with this linespec.  For example, if the option is
  58        `-probe', and the LINESPECP is `-probe abc', the function should
  59        return 1 and set LINESPECP to `abc'.  */
  60
  61     int (*is_linespec) (const char **linespecp);
  62
  63     /* Function that should fill PROBES with known probes from OBJFILE.  */
  64
  65     void (*get_probes) (VEC (probe_p) **probes, struct objfile *objfile);
  66
  67     /* Compute the probe's relocated address.  OBJFILE is the objfile
  68        in which the probe originated.  */
  69
  70     CORE_ADDR (*get_probe_address) (struct probe *probe,
  71                                     struct objfile *objfile);
  72
  73     /* Return the number of arguments of PROBE.  */
  74
  75     unsigned (*get_probe_argument_count) (struct probe *probe,
  76                                           struct frame_info *frame);
  77
  78     /* Return 1 if the probe interface can evaluate the arguments of probe
  79        PROBE, zero otherwise.  See the comments on
  80        sym_probe_fns:can_evaluate_probe_arguments for more details.  */
  81
  82     int (*can_evaluate_probe_arguments) (struct probe *probe);
  83
  84     /* Evaluate the Nth argument from the PROBE, returning a value
  85        corresponding to it.  The argument number is represented N.  */
  86
  87     struct value *(*evaluate_probe_argument) (struct probe *probe,
  88                                               unsigned n,
  89                                               struct frame_info *frame);
  90
  91     /* Compile the Nth argument of the PROBE to an agent expression.
  92        The argument number is represented by N.  */
  93
  94     void (*compile_to_ax) (struct probe *probe, struct agent_expr *aexpr,
  95                            struct axs_value *axs_value, unsigned n);
  96
  97     /* Set the semaphore associated with the PROBE.  This function only makes
  98        sense if the probe has a concept of semaphore associated to a
  99        probe, otherwise it can be set to NULL.  */
 100
 101     void (*set_semaphore) (struct probe *probe, struct objfile *objfile,
 102                            struct gdbarch *gdbarch);
 103
 104     /* Clear the semaphore associated with the PROBE.  This function only
 105        makes sense if the probe has a concept of semaphore associated to
 106        a probe, otherwise it can be set to NULL.  */
 107
 108     void (*clear_semaphore) (struct probe *probe, struct objfile *objfile,
 109                              struct gdbarch *gdbarch);
 110
 111     /* Function called to destroy PROBE's specific data.  This function
 112        shall not free PROBE itself.  */
 113
 114     void (*destroy) (struct probe *probe);
 115
 116     /* Return a pointer to a name identifying the probe type.  This is
 117        the string that will be displayed in the "Type" column of the
 118        `info probes' command.  */
 119
 120     const char *(*type_name) (struct probe *probe);
 121
 122     /* Function responsible for providing the extra fields that will be
 123        printed in the `info probes' command.  It should fill HEADS
 124        with whatever extra fields it needs.  If the backend doesn't need
 125        to print extra fields, it can set this method to NULL.  */
 126
 127     void (*gen_info_probes_table_header) (VEC (info_probe_column_s) **heads);
 128
 129     /* Function that will fill VALUES with the values of the extra fields
 130        to be printed for PROBE.  If the backend implements the
 131        `gen_ui_out_table_header' method, then it should implement
 132        this method as well.  The backend should also guarantee that the
 133        order and the number of values in the vector is exactly the same
 134        as the order of the extra fields provided in the method
 135        `gen_ui_out_table_header'.  If a certain field is to be skipped
 136        when printing the information, you can push a NULL value in that
 137        position in the vector.  */
 138
 139     void (*gen_info_probes_table_values) (struct probe *probe,
 140                                           VEC (const_char_ptr) **values);
 141   };
 142
 143 /* Definition of a vector of probe_ops.  */
 144
 145 typedef const struct probe_ops *probe_ops_cp;
 146 DEF_VEC_P (probe_ops_cp);
 147 extern VEC (probe_ops_cp) *all_probe_ops;
 148
 149 /* The probe_ops associated with the generic probe.  */
 150
 151 extern const struct probe_ops probe_ops_any;
 152
 153 /* Helper function that, given KEYWORDS, iterate over it trying to match
 154    each keyword with LINESPECP.  If it succeeds, it updates the LINESPECP
 155    pointer and returns 1.  Otherwise, nothing is done to LINESPECP and zero
 156    is returned.  */
 157
 158 extern int probe_is_linespec_by_keyword (const char **linespecp,
 159                                          const char *const *keywords);
 160
 161 /* Return specific PROBE_OPS * matching *LINESPECP and possibly updating
 162    *LINESPECP to skip its "-probe-type " prefix.  Return &probe_ops_any if
 163    *LINESPECP matches "-probe ", that is any unspecific probe.  Return NULL if
 164    *LINESPECP is not identified as any known probe type, *LINESPECP is not
 165    modified in such case.  */
 166
 167 extern const struct probe_ops *probe_linespec_to_ops (const char **linespecp);
 168
 169 /* The probe itself.  The struct contains generic information about the
 170    probe, and then some specific information which should be stored in
 171    the `probe_info' field.  */
 172
 173 struct probe
 174   {
 175     /* The operations associated with this probe.  */
 176     const struct probe_ops *pops;
 177
 178     /* The probe's architecture.  */
 179     struct gdbarch *arch;
 180
 181     /* The name of the probe.  */
 182     const char *name;
 183
 184     /* The provider of the probe.  It generally defaults to the name of
 185        the objfile which contains the probe.  */
 186     const char *provider;
 187
 188     /* The address where the probe is inserted, relative to
 189        SECT_OFF_TEXT.  */
 190     CORE_ADDR address;
 191   };
 192
 193 /* A bound probe holds a pointer to a probe and a pointer to the
 194    probe's defining objfile.  This is needed because probes are
 195    independent of the program space and thus require relocation at
 196    their point of use.  */
 197
 198 struct bound_probe
 199   {
 200     /* The probe.  */
 201
 202     struct probe *probe;
 203
 204     /* The objfile in which the probe originated.  */
 205
 206     struct objfile *objfile;
 207   };
 208
 209 /* A helper for linespec that decodes a probe specification.  It returns a
 210    symtabs_and_lines object and updates *ARGPTR or throws an error.  */
 211
 212 extern struct symtabs_and_lines parse_probes (char **argptr,
 213                                               struct linespec_result *canon);
 214
 215 /* Helper function to register the proper probe_ops to a newly created probe.
 216    This function is mainly called from `sym_get_probes'.  */
 217
 218 extern void register_probe_ops (struct probe *probe);
 219
 220 /* Given a PC, find an associated probe.  If a probe is found, return
 221    it.  If no probe is found, return a bound probe whose fields are
 222    both NULL.  */
 223
 224 extern struct bound_probe find_probe_by_pc (CORE_ADDR pc);
 225
 226 /* Search OBJFILE for a probe with the given PROVIDER, NAME.  Return a
 227    VEC of all probes that were found.  If no matching probe is found,
 228    return NULL.  The caller must free the VEC.  */
 229
 230 extern VEC (probe_p) *find_probes_in_objfile (struct objfile *objfile,
 231                                               const char *provider,
 232                                               const char *name);
 233
 234 /* Generate a `info probes' command output for probe_ops represented by
 235    POPS.  If POPS is NULL it considers any probes types.  It is a helper
 236    function that can be used by the probe backends to print their
 237    `info probe TYPE'.  */
 238
 239 extern void info_probes_for_ops (const char *arg, int from_tty,
 240                                  const struct probe_ops *pops);
 241
 242 /* Return the `cmd_list_element' associated with the `info probes' command,
 243    or create a new one if it doesn't exist.  Helper function that serves the
 244    purpose of avoiding the case of a backend using the `cmd_list_element'
 245    associated with `info probes', without having it registered yet.  */
 246
 247 extern struct cmd_list_element **info_probes_cmdlist_get (void);
 248
 249 /* Compute the probe's relocated address.  OBJFILE is the objfile in
 250    which the probe originated.  */
 251
 252 extern CORE_ADDR get_probe_address (struct probe *probe,
 253                                     struct objfile *objfile);
 254
 255 /* Return the argument count of the specified probe.  */
 256
 257 extern unsigned get_probe_argument_count (struct probe *probe,
 258                                           struct frame_info *frame);
 259
 260 /* Return 1 if the probe interface associated with PROBE can evaluate
 261    arguments, zero otherwise.  See the comments on the definition of
 262    sym_probe_fns:can_evaluate_probe_arguments for more details.  */
 263
 264 extern int can_evaluate_probe_arguments (struct probe *probe);
 265
 266 /* Evaluate argument N of the specified probe.  N must be between 0
 267    inclusive and get_probe_argument_count exclusive.  */
 268
 269 extern struct value *evaluate_probe_argument (struct probe *probe,
 270                                               unsigned n,
 271                                               struct frame_info *frame);
 272
 273 /* A convenience function that finds a probe at the PC in FRAME and
 274    evaluates argument N, with 0 <= N < number_of_args.  If there is no
 275    probe at that location, or if the probe does not have enough arguments,
 276    this returns NULL.  */
 277
 278 extern struct value *probe_safe_evaluate_at_pc (struct frame_info *frame,
 279                                                 unsigned n);
 280
 281 #endif /* !defined (PROBE_H) */