gdb/btrace.h

   1 /* Branch trace support for GDB, the GNU debugger.
   2
   3    Copyright (C) 2013-2015 Free Software Foundation, Inc.
   4
   5    Contributed by Intel Corp. <markus.t.metzger@intel.com>.
   6
   7    This file is part of GDB.
   8
   9    This program is free software; you can redistribute it and/or modify
  10    it under the terms of the GNU General Public License as published by
  11    the Free Software Foundation; either version 3 of the License, or
  12    (at your option) any later version.
  13
  14    This program is distributed in the hope that it will be useful,
  15    but WITHOUT ANY WARRANTY; without even the implied warranty of
  16    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  17    GNU General Public License for more details.
  18
  19    You should have received a copy of the GNU General Public License
  20    along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
  21
  22 #ifndef BTRACE_H
  23 #define BTRACE_H
  24
  25 /* Branch tracing (btrace) is a per-thread control-flow execution trace of the
  26    inferior.  For presentation purposes, the branch trace is represented as a
  27    list of sequential control-flow blocks, one such list per thread.  */
  28
  29 #include "btrace-common.h"
  30
  31 struct thread_info;
  32 struct btrace_function;
  33
  34 /* A branch trace instruction.
  35
  36    This represents a single instruction in a branch trace.  */
  37 struct btrace_insn
  38 {
  39   /* The address of this instruction.  */
  40   CORE_ADDR pc;
  41 };
  42
  43 /* A vector of branch trace instructions.  */
  44 typedef struct btrace_insn btrace_insn_s;
  45 DEF_VEC_O (btrace_insn_s);
  46
  47 /* A doubly-linked list of branch trace function segments.  */
  48 struct btrace_func_link
  49 {
  50   struct btrace_function *prev;
  51   struct btrace_function *next;
  52 };
  53
  54 /* Flags for btrace function segments.  */
  55 enum btrace_function_flag
  56 {
  57   /* The 'up' link interpretation.
  58      If set, it points to the function segment we returned to.
  59      If clear, it points to the function segment we called from.  */
  60   BFUN_UP_LINKS_TO_RET = (1 << 0),
  61
  62   /* The 'up' link points to a tail call.  This obviously only makes sense
  63      if bfun_up_links_to_ret is clear.  */
  64   BFUN_UP_LINKS_TO_TAILCALL = (1 << 1)
  65 };
  66
  67 /* A branch trace function segment.
  68
  69    This represents a function segment in a branch trace, i.e. a consecutive
  70    number of instructions belonging to the same function.
  71
  72    We do not allow function segments without any instructions.  */
  73 struct btrace_function
  74 {
  75   /* The full and minimal symbol for the function.  Both may be NULL.  */
  76   struct minimal_symbol *msym;
  77   struct symbol *sym;
  78
  79   /* The previous and next segment belonging to the same function.
  80      If a function calls another function, the former will have at least
  81      two segments: one before the call and another after the return.  */
  82   struct btrace_func_link segment;
  83
  84   /* The previous and next function in control flow order.  */
  85   struct btrace_func_link flow;
  86
  87   /* The directly preceding function segment in a (fake) call stack.  */
  88   struct btrace_function *up;
  89
  90   /* The instructions in this function segment.
  91      The instruction vector will never be empty.  */
  92   VEC (btrace_insn_s) *insn;
  93
  94   /* The instruction number offset for the first instruction in this
  95      function segment.  */
  96   unsigned int insn_offset;
  97
  98   /* The function number in control-flow order.  */
  99   unsigned int number;
 100
 101   /* The function level in a back trace across the entire branch trace.
 102      A caller's level is one lower than the level of its callee.
 103
 104      Levels can be negative if we see returns for which we have not seen
 105      the corresponding calls.  The branch trace thread information provides
 106      a fixup to normalize function levels so the smallest level is zero.  */
 107   int level;
 108
 109   /* The source line range of this function segment (both inclusive).  */
 110   int lbegin, lend;
 111
 112   /* A bit-vector of btrace_function_flag.  */
 113   enum btrace_function_flag flags;
 114 };
 115
 116 /* A branch trace instruction iterator.  */
 117 struct btrace_insn_iterator
 118 {
 119   /* The branch trace function segment containing the instruction.
 120      Will never be NULL.  */
 121   const struct btrace_function *function;
 122
 123   /* The index into the function segment's instruction vector.  */
 124   unsigned int index;
 125 };
 126
 127 /* A branch trace function call iterator.  */
 128 struct btrace_call_iterator
 129 {
 130   /* The branch trace information for this thread.  Will never be NULL.  */
 131   const struct btrace_thread_info *btinfo;
 132
 133   /* The branch trace function segment.
 134      This will be NULL for the iterator pointing to the end of the trace.  */
 135   const struct btrace_function *function;
 136 };
 137
 138 /* Branch trace iteration state for "record instruction-history".  */
 139 struct btrace_insn_history
 140 {
 141   /* The branch trace instruction range from BEGIN (inclusive) to
 142      END (exclusive) that has been covered last time.  */
 143   struct btrace_insn_iterator begin;
 144   struct btrace_insn_iterator end;
 145 };
 146
 147 /* Branch trace iteration state for "record function-call-history".  */
 148 struct btrace_call_history
 149 {
 150   /* The branch trace function range from BEGIN (inclusive) to END (exclusive)
 151      that has been covered last time.  */
 152   struct btrace_call_iterator begin;
 153   struct btrace_call_iterator end;
 154 };
 155
 156 /* Branch trace thread flags.  */
 157 enum btrace_thread_flag
 158 {
 159   /* The thread is to be stepped forwards.  */
 160   BTHR_STEP = (1 << 0),
 161
 162   /* The thread is to be stepped backwards.  */
 163   BTHR_RSTEP = (1 << 1),
 164
 165   /* The thread is to be continued forwards.  */
 166   BTHR_CONT = (1 << 2),
 167
 168   /* The thread is to be continued backwards.  */
 169   BTHR_RCONT = (1 << 3),
 170
 171   /* The thread is to be moved.  */
 172   BTHR_MOVE = (BTHR_STEP | BTHR_RSTEP | BTHR_CONT | BTHR_RCONT)
 173 };
 174
 175 /* Branch trace information per thread.
 176
 177    This represents the branch trace configuration as well as the entry point
 178    into the branch trace data.  For the latter, it also contains the index into
 179    an array of branch trace blocks used for iterating though the branch trace
 180    blocks of a thread.  */
 181 struct btrace_thread_info
 182 {
 183   /* The target branch trace information for this thread.
 184
 185      This contains the branch trace configuration as well as any
 186      target-specific information necessary for implementing branch tracing on
 187      the underlying architecture.  */
 188   struct btrace_target_info *target;
 189
 190   /* The current branch trace for this thread (both inclusive).
 191
 192      The last instruction of END is the current instruction, which is not
 193      part of the execution history.
 194      Both will be NULL if there is no branch trace available.  If there is
 195      branch trace available, both will be non-NULL.  */
 196   struct btrace_function *begin;
 197   struct btrace_function *end;
 198
 199   /* The function level offset.  When added to each function's LEVEL,
 200      this normalizes the function levels such that the smallest level
 201      becomes zero.  */
 202   int level;
 203
 204   /* A bit-vector of btrace_thread_flag.  */
 205   enum btrace_thread_flag flags;
 206
 207   /* The instruction history iterator.  */
 208   struct btrace_insn_history *insn_history;
 209
 210   /* The function call history iterator.  */
 211   struct btrace_call_history *call_history;
 212
 213   /* The current replay position.  NULL if not replaying.  */
 214   struct btrace_insn_iterator *replay;
 215 };
 216
 217 /* Enable branch tracing for a thread.  */
 218 extern void btrace_enable (struct thread_info *tp,
 219                            const struct btrace_config *conf);
 220
 221 /* Get the branch trace configuration for a thread.
 222    Return NULL if branch tracing is not enabled for that thread.  */
 223 extern const struct btrace_config *
 224   btrace_conf (const struct btrace_thread_info *);
 225
 226 /* Disable branch tracing for a thread.
 227    This will also delete the current branch trace data.  */
 228 extern void btrace_disable (struct thread_info *);
 229
 230 /* Disable branch tracing for a thread during teardown.
 231    This is similar to btrace_disable, except that it will use
 232    target_teardown_btrace instead of target_disable_btrace.  */
 233 extern void btrace_teardown (struct thread_info *);
 234
 235 /* Fetch the branch trace for a single thread.  */
 236 extern void btrace_fetch (struct thread_info *);
 237
 238 /* Clear the branch trace for a single thread.  */
 239 extern void btrace_clear (struct thread_info *);
 240
 241 /* Clear the branch trace for all threads when an object file goes away.  */
 242 extern void btrace_free_objfile (struct objfile *);
 243
 244 /* Parse a branch trace xml document XML into DATA.  */
 245 extern void parse_xml_btrace (struct btrace_data *data, const char *xml);
 246
 247 /* Parse a branch trace configuration xml document XML into CONF.  */
 248 extern void parse_xml_btrace_conf (struct btrace_config *conf, const char *xml);
 249
 250 /* Dereference a branch trace instruction iterator.  Return a pointer to the
 251    instruction the iterator points to.  */
 252 extern const struct btrace_insn *
 253   btrace_insn_get (const struct btrace_insn_iterator *);
 254
 255 /* Return the instruction number for a branch trace iterator.
 256    Returns one past the maximum instruction number for the end iterator.
 257    Returns zero if the iterator does not point to a valid instruction.  */
 258 extern unsigned int btrace_insn_number (const struct btrace_insn_iterator *);
 259
 260 /* Initialize a branch trace instruction iterator to point to the begin/end of
 261    the branch trace.  Throws an error if there is no branch trace.  */
 262 extern void btrace_insn_begin (struct btrace_insn_iterator *,
 263                                const struct btrace_thread_info *);
 264 extern void btrace_insn_end (struct btrace_insn_iterator *,
 265                              const struct btrace_thread_info *);
 266
 267 /* Increment/decrement a branch trace instruction iterator by at most STRIDE
 268    instructions.  Return the number of instructions by which the instruction
 269    iterator has been advanced.
 270    Returns zero, if the operation failed or STRIDE had been zero.  */
 271 extern unsigned int btrace_insn_next (struct btrace_insn_iterator *,
 272                                       unsigned int stride);
 273 extern unsigned int btrace_insn_prev (struct btrace_insn_iterator *,
 274                                       unsigned int stride);
 275
 276 /* Compare two branch trace instruction iterators.
 277    Return a negative number if LHS < RHS.
 278    Return zero if LHS == RHS.
 279    Return a positive number if LHS > RHS.  */
 280 extern int btrace_insn_cmp (const struct btrace_insn_iterator *lhs,
 281                             const struct btrace_insn_iterator *rhs);
 282
 283 /* Find an instruction in the function branch trace by its number.
 284    If the instruction is found, initialize the branch trace instruction
 285    iterator to point to this instruction and return non-zero.
 286    Return zero otherwise.  */
 287 extern int btrace_find_insn_by_number (struct btrace_insn_iterator *,
 288                                        const struct btrace_thread_info *,
 289                                        unsigned int number);
 290
 291 /* Dereference a branch trace call iterator.  Return a pointer to the
 292    function the iterator points to or NULL if the interator points past
 293    the end of the branch trace.  */
 294 extern const struct btrace_function *
 295   btrace_call_get (const struct btrace_call_iterator *);
 296
 297 /* Return the function number for a branch trace call iterator.
 298    Returns one past the maximum function number for the end iterator.
 299    Returns zero if the iterator does not point to a valid function.  */
 300 extern unsigned int btrace_call_number (const struct btrace_call_iterator *);
 301
 302 /* Initialize a branch trace call iterator to point to the begin/end of
 303    the branch trace.  Throws an error if there is no branch trace.  */
 304 extern void btrace_call_begin (struct btrace_call_iterator *,
 305                                const struct btrace_thread_info *);
 306 extern void btrace_call_end (struct btrace_call_iterator *,
 307                              const struct btrace_thread_info *);
 308
 309 /* Increment/decrement a branch trace call iterator by at most STRIDE function
 310    segments.  Return the number of function segments by which the call
 311    iterator has been advanced.
 312    Returns zero, if the operation failed or STRIDE had been zero.  */
 313 extern unsigned int btrace_call_next (struct btrace_call_iterator *,
 314                                       unsigned int stride);
 315 extern unsigned int btrace_call_prev (struct btrace_call_iterator *,
 316                                       unsigned int stride);
 317
 318 /* Compare two branch trace call iterators.
 319    Return a negative number if LHS < RHS.
 320    Return zero if LHS == RHS.
 321    Return a positive number if LHS > RHS.  */
 322 extern int btrace_call_cmp (const struct btrace_call_iterator *lhs,
 323                             const struct btrace_call_iterator *rhs);
 324
 325 /* Find a function in the function branch trace by its NUMBER.
 326    If the function is found, initialize the branch trace call
 327    iterator to point to this function and return non-zero.
 328    Return zero otherwise.  */
 329 extern int btrace_find_call_by_number (struct btrace_call_iterator *,
 330                                        const struct btrace_thread_info *,
 331                                        unsigned int number);
 332
 333 /* Set the branch trace instruction history from BEGIN (inclusive) to
 334    END (exclusive).  */
 335 extern void btrace_set_insn_history (struct btrace_thread_info *,
 336                                      const struct btrace_insn_iterator *begin,
 337                                      const struct btrace_insn_iterator *end);
 338
 339 /* Set the branch trace function call history from BEGIN (inclusive) to
 340    END (exclusive).  */
 341 extern void btrace_set_call_history (struct btrace_thread_info *,
 342                                      const struct btrace_call_iterator *begin,
 343                                      const struct btrace_call_iterator *end);
 344
 345 /* Determine if branch tracing is currently replaying TP.  */
 346 extern int btrace_is_replaying (struct thread_info *tp);
 347
 348 /* Return non-zero if the branch trace for TP is empty; zero otherwise.  */
 349 extern int btrace_is_empty (struct thread_info *tp);
 350
 351 /* Create a cleanup for DATA.  */
 352 extern struct cleanup *make_cleanup_btrace_data (struct btrace_data *data);
 353
 354 #endif /* BTRACE_H */