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     /* Function responsible for providing the extra fields that will be
 117        printed in the `info probes' command.  It should fill HEADS
 118        with whatever extra fields it needs.  If the backend doesn't need
 119        to print extra fields, it can set this method to NULL.  */
 120
 121     void (*gen_info_probes_table_header) (VEC (info_probe_column_s) **heads);
 122
 123     /* Function that will fill VALUES with the values of the extra fields
 124        to be printed for PROBE.  If the backend implements the
 125        `gen_ui_out_table_header' method, then it should implement
 126        this method as well.  The backend should also guarantee that the
 127        order and the number of values in the vector is exactly the same
 128        as the order of the extra fields provided in the method
 129        `gen_ui_out_table_header'.  If a certain field is to be skipped
 130        when printing the information, you can push a NULL value in that
 131        position in the vector.  */
 132
 133     void (*gen_info_probes_table_values) (struct probe *probe,
 134                                           VEC (const_char_ptr) **values);
 135   };
 136
 137 /* Definition of a vector of probe_ops.  */
 138
 139 typedef const struct probe_ops *probe_ops_cp;
 140 DEF_VEC_P (probe_ops_cp);
 141 extern VEC (probe_ops_cp) *all_probe_ops;
 142
 143 /* The probe_ops associated with the generic probe.  */
 144
 145 extern const struct probe_ops probe_ops_any;
 146
 147 /* Helper function that, given KEYWORDS, iterate over it trying to match
 148    each keyword with LINESPECP.  If it succeeds, it updates the LINESPECP
 149    pointer and returns 1.  Otherwise, nothing is done to LINESPECP and zero
 150    is returned.  */
 151
 152 extern int probe_is_linespec_by_keyword (const char **linespecp,
 153                                          const char *const *keywords);
 154
 155 /* Return specific PROBE_OPS * matching *LINESPECP and possibly updating
 156    *LINESPECP to skip its "-probe-type " prefix.  Return &probe_ops_any if
 157    *LINESPECP matches "-probe ", that is any unspecific probe.  Return NULL if
 158    *LINESPECP is not identified as any known probe type, *LINESPECP is not
 159    modified in such case.  */
 160
 161 extern const struct probe_ops *probe_linespec_to_ops (const char **linespecp);
 162
 163 /* The probe itself.  The struct contains generic information about the
 164    probe, and then some specific information which should be stored in
 165    the `probe_info' field.  */
 166
 167 struct probe
 168   {
 169     /* The operations associated with this probe.  */
 170     const struct probe_ops *pops;
 171
 172     /* The probe's architecture.  */
 173     struct gdbarch *arch;
 174
 175     /* The name of the probe.  */
 176     const char *name;
 177
 178     /* The provider of the probe.  It generally defaults to the name of
 179        the objfile which contains the probe.  */
 180     const char *provider;
 181
 182     /* The address where the probe is inserted, relative to
 183        SECT_OFF_TEXT.  */
 184     CORE_ADDR address;
 185   };
 186
 187 /* A bound probe holds a pointer to a probe and a pointer to the
 188    probe's defining objfile.  This is needed because probes are
 189    independent of the program space and thus require relocation at
 190    their point of use.  */
 191
 192 struct bound_probe
 193   {
 194     /* The probe.  */
 195
 196     struct probe *probe;
 197
 198     /* The objfile in which the probe originated.  */
 199
 200     struct objfile *objfile;
 201   };
 202
 203 /* A helper for linespec that decodes a probe specification.  It returns a
 204    symtabs_and_lines object and updates *ARGPTR or throws an error.  */
 205
 206 extern struct symtabs_and_lines parse_probes (char **argptr,
 207                                               struct linespec_result *canon);
 208
 209 /* Helper function to register the proper probe_ops to a newly created probe.
 210    This function is mainly called from `sym_get_probes'.  */
 211
 212 extern void register_probe_ops (struct probe *probe);
 213
 214 /* Given a PC, find an associated probe.  If a probe is found, return
 215    it.  If no probe is found, return a bound probe whose fields are
 216    both NULL.  */
 217
 218 extern struct bound_probe find_probe_by_pc (CORE_ADDR pc);
 219
 220 /* Search OBJFILE for a probe with the given PROVIDER, NAME.  Return a
 221    VEC of all probes that were found.  If no matching probe is found,
 222    return NULL.  The caller must free the VEC.  */
 223
 224 extern VEC (probe_p) *find_probes_in_objfile (struct objfile *objfile,
 225                                               const char *provider,
 226                                               const char *name);
 227
 228 /* Generate a `info probes' command output for probe_ops represented by
 229    POPS.  If POPS is NULL it considers any probes types.  It is a helper
 230    function that can be used by the probe backends to print their
 231    `info probe TYPE'.  */
 232
 233 extern void info_probes_for_ops (const char *arg, int from_tty,
 234                                  const struct probe_ops *pops);
 235
 236 /* Return the `cmd_list_element' associated with the `info probes' command,
 237    or create a new one if it doesn't exist.  Helper function that serves the
 238    purpose of avoiding the case of a backend using the `cmd_list_element'
 239    associated with `info probes', without having it registered yet.  */
 240
 241 extern struct cmd_list_element **info_probes_cmdlist_get (void);
 242
 243 /* Compute the probe's relocated address.  OBJFILE is the objfile in
 244    which the probe originated.  */
 245
 246 extern CORE_ADDR get_probe_address (struct probe *probe,
 247                                     struct objfile *objfile);
 248
 249 /* Return the argument count of the specified probe.  */
 250
 251 extern unsigned get_probe_argument_count (struct probe *probe,
 252                                           struct frame_info *frame);
 253
 254 /* Return 1 if the probe interface associated with PROBE can evaluate
 255    arguments, zero otherwise.  See the comments on the definition of
 256    sym_probe_fns:can_evaluate_probe_arguments for more details.  */
 257
 258 extern int can_evaluate_probe_arguments (struct probe *probe);
 259
 260 /* Evaluate argument N of the specified probe.  N must be between 0
 261    inclusive and get_probe_argument_count exclusive.  */
 262
 263 extern struct value *evaluate_probe_argument (struct probe *probe,
 264                                               unsigned n,
 265                                               struct frame_info *frame);
 266
 267 /* A convenience function that finds a probe at the PC in FRAME and
 268    evaluates argument N, with 0 <= N < number_of_args.  If there is no
 269    probe at that location, or if the probe does not have enough arguments,
 270    this returns NULL.  */
 271
 272 extern struct value *probe_safe_evaluate_at_pc (struct frame_info *frame,
 273                                                 unsigned n);
 274
 275 #endif /* !defined (PROBE_H) */