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 #include "target/waitstatus.h" /* For enum target_stop_reason.  */
  31
  32 #if defined (HAVE_LIBIPT)
  33 #  include <intel-pt.h>
  34 #endif
  35
  36 struct thread_info;
  37 struct btrace_function;
  38
  39 /* A coarse instruction classification.  */
  40 enum btrace_insn_class
  41 {
  42   /* The instruction is something not listed below.  */
  43   BTRACE_INSN_OTHER,
  44
  45   /* The instruction is a function call.  */
  46   BTRACE_INSN_CALL,
  47
  48   /* The instruction is a function return.  */
  49   BTRACE_INSN_RETURN,
  50
  51   /* The instruction is an unconditional jump.  */
  52   BTRACE_INSN_JUMP
  53 };
  54
  55 /* A branch trace instruction.
  56
  57    This represents a single instruction in a branch trace.  */
  58 struct btrace_insn
  59 {
  60   /* The address of this instruction.  */
  61   CORE_ADDR pc;
  62
  63   /* The size of this instruction in bytes.  */
  64   gdb_byte size;
  65
  66   /* The instruction class of this instruction.  */
  67   enum btrace_insn_class iclass;
  68 };
  69
  70 /* A vector of branch trace instructions.  */
  71 typedef struct btrace_insn btrace_insn_s;
  72 DEF_VEC_O (btrace_insn_s);
  73
  74 /* A doubly-linked list of branch trace function segments.  */
  75 struct btrace_func_link
  76 {
  77   struct btrace_function *prev;
  78   struct btrace_function *next;
  79 };
  80
  81 /* Flags for btrace function segments.  */
  82 enum btrace_function_flag
  83 {
  84   /* The 'up' link interpretation.
  85      If set, it points to the function segment we returned to.
  86      If clear, it points to the function segment we called from.  */
  87   BFUN_UP_LINKS_TO_RET = (1 << 0),
  88
  89   /* The 'up' link points to a tail call.  This obviously only makes sense
  90      if bfun_up_links_to_ret is clear.  */
  91   BFUN_UP_LINKS_TO_TAILCALL = (1 << 1)
  92 };
  93
  94 /* Decode errors for the BTS recording format.  */
  95 enum btrace_bts_error
  96 {
  97   /* The instruction trace overflowed the end of the trace block.  */
  98   BDE_BTS_OVERFLOW = 1,
  99
 100   /* The instruction size could not be determined.  */
 101   BDE_BTS_INSN_SIZE
 102 };
 103
 104 /* Decode errors for the Intel(R) Processor Trace recording format.  */
 105 enum btrace_pt_error
 106 {
 107   /* The user cancelled trace processing.  */
 108   BDE_PT_USER_QUIT = 1,
 109
 110   /* Tracing was temporarily disabled.  */
 111   BDE_PT_DISABLED,
 112
 113   /* Trace recording overflowed.  */
 114   BDE_PT_OVERFLOW
 115
 116   /* Negative numbers are used by the decoder library.  */
 117 };
 118
 119 /* A branch trace function segment.
 120
 121    This represents a function segment in a branch trace, i.e. a consecutive
 122    number of instructions belonging to the same function.
 123
 124    In case of decode errors, we add an empty function segment to indicate
 125    the gap in the trace.
 126
 127    We do not allow function segments without instructions otherwise.  */
 128 struct btrace_function
 129 {
 130   /* The full and minimal symbol for the function.  Both may be NULL.  */
 131   struct minimal_symbol *msym;
 132   struct symbol *sym;
 133
 134   /* The previous and next segment belonging to the same function.
 135      If a function calls another function, the former will have at least
 136      two segments: one before the call and another after the return.  */
 137   struct btrace_func_link segment;
 138
 139   /* The previous and next function in control flow order.  */
 140   struct btrace_func_link flow;
 141
 142   /* The directly preceding function segment in a (fake) call stack.  */
 143   struct btrace_function *up;
 144
 145   /* The instructions in this function segment.
 146      The instruction vector will be empty if the function segment
 147      represents a decode error.  */
 148   VEC (btrace_insn_s) *insn;
 149
 150   /* The error code of a decode error that led to a gap.
 151      Must be zero unless INSN is empty; non-zero otherwise.  */
 152   int errcode;
 153
 154   /* The instruction number offset for the first instruction in this
 155      function segment.
 156      If INSN is empty this is the insn_offset of the succeding function
 157      segment in control-flow order.  */
 158   unsigned int insn_offset;
 159
 160   /* The function number in control-flow order.
 161      If INSN is empty indicating a gap in the trace due to a decode error,
 162      we still count the gap as a function.  */
 163   unsigned int number;
 164
 165   /* The function level in a back trace across the entire branch trace.
 166      A caller's level is one lower than the level of its callee.
 167
 168      Levels can be negative if we see returns for which we have not seen
 169      the corresponding calls.  The branch trace thread information provides
 170      a fixup to normalize function levels so the smallest level is zero.  */
 171   int level;
 172
 173   /* A bit-vector of btrace_function_flag.  */
 174   enum btrace_function_flag flags;
 175 };
 176
 177 /* A branch trace instruction iterator.  */
 178 struct btrace_insn_iterator
 179 {
 180   /* The branch trace function segment containing the instruction.
 181      Will never be NULL.  */
 182   const struct btrace_function *function;
 183
 184   /* The index into the function segment's instruction vector.  */
 185   unsigned int index;
 186 };
 187
 188 /* A branch trace function call iterator.  */
 189 struct btrace_call_iterator
 190 {
 191   /* The branch trace information for this thread.  Will never be NULL.  */
 192   const struct btrace_thread_info *btinfo;
 193
 194   /* The branch trace function segment.
 195      This will be NULL for the iterator pointing to the end of the trace.  */
 196   const struct btrace_function *function;
 197 };
 198
 199 /* Branch trace iteration state for "record instruction-history".  */
 200 struct btrace_insn_history
 201 {
 202   /* The branch trace instruction range from BEGIN (inclusive) to
 203      END (exclusive) that has been covered last time.  */
 204   struct btrace_insn_iterator begin;
 205   struct btrace_insn_iterator end;
 206 };
 207
 208 /* Branch trace iteration state for "record function-call-history".  */
 209 struct btrace_call_history
 210 {
 211   /* The branch trace function range from BEGIN (inclusive) to END (exclusive)
 212      that has been covered last time.  */
 213   struct btrace_call_iterator begin;
 214   struct btrace_call_iterator end;
 215 };
 216
 217 /* Branch trace thread flags.  */
 218 enum btrace_thread_flag
 219 {
 220   /* The thread is to be stepped forwards.  */
 221   BTHR_STEP = (1 << 0),
 222
 223   /* The thread is to be stepped backwards.  */
 224   BTHR_RSTEP = (1 << 1),
 225
 226   /* The thread is to be continued forwards.  */
 227   BTHR_CONT = (1 << 2),
 228
 229   /* The thread is to be continued backwards.  */
 230   BTHR_RCONT = (1 << 3),
 231
 232   /* The thread is to be moved.  */
 233   BTHR_MOVE = (BTHR_STEP | BTHR_RSTEP | BTHR_CONT | BTHR_RCONT)
 234 };
 235
 236 /* Branch trace information per thread.
 237
 238    This represents the branch trace configuration as well as the entry point
 239    into the branch trace data.  For the latter, it also contains the index into
 240    an array of branch trace blocks used for iterating though the branch trace
 241    blocks of a thread.  */
 242 struct btrace_thread_info
 243 {
 244   /* The target branch trace information for this thread.
 245
 246      This contains the branch trace configuration as well as any
 247      target-specific information necessary for implementing branch tracing on
 248      the underlying architecture.  */
 249   struct btrace_target_info *target;
 250
 251   /* The raw branch trace data for the below branch trace.  */
 252   struct btrace_data data;
 253
 254   /* The current branch trace for this thread (both inclusive).
 255
 256      The last instruction of END is the current instruction, which is not
 257      part of the execution history.
 258      Both will be NULL if there is no branch trace available.  If there is
 259      branch trace available, both will be non-NULL.  */
 260   struct btrace_function *begin;
 261   struct btrace_function *end;
 262
 263   /* The function level offset.  When added to each function's LEVEL,
 264      this normalizes the function levels such that the smallest level
 265      becomes zero.  */
 266   int level;
 267
 268   /* The number of gaps in the trace.  */
 269   unsigned int ngaps;
 270
 271   /* A bit-vector of btrace_thread_flag.  */
 272   enum btrace_thread_flag flags;
 273
 274   /* The instruction history iterator.  */
 275   struct btrace_insn_history *insn_history;
 276
 277   /* The function call history iterator.  */
 278   struct btrace_call_history *call_history;
 279
 280   /* The current replay position.  NULL if not replaying.
 281      Gaps are skipped during replay, so REPLAY always points to a valid
 282      instruction.  */
 283   struct btrace_insn_iterator *replay;
 284
 285   /* Why the thread stopped, if we need to track it.  */
 286   enum target_stop_reason stop_reason;
 287 };
 288
 289 /* Enable branch tracing for a thread.  */
 290 extern void btrace_enable (struct thread_info *tp,
 291                            const struct btrace_config *conf);
 292
 293 /* Get the branch trace configuration for a thread.
 294    Return NULL if branch tracing is not enabled for that thread.  */
 295 extern const struct btrace_config *
 296   btrace_conf (const struct btrace_thread_info *);
 297
 298 /* Disable branch tracing for a thread.
 299    This will also delete the current branch trace data.  */
 300 extern void btrace_disable (struct thread_info *);
 301
 302 /* Disable branch tracing for a thread during teardown.
 303    This is similar to btrace_disable, except that it will use
 304    target_teardown_btrace instead of target_disable_btrace.  */
 305 extern void btrace_teardown (struct thread_info *);
 306
 307 /* Fetch the branch trace for a single thread.  */
 308 extern void btrace_fetch (struct thread_info *);
 309
 310 /* Clear the branch trace for a single thread.  */
 311 extern void btrace_clear (struct thread_info *);
 312
 313 /* Clear the branch trace for all threads when an object file goes away.  */
 314 extern void btrace_free_objfile (struct objfile *);
 315
 316 /* Parse a branch trace xml document XML into DATA.  */
 317 extern void parse_xml_btrace (struct btrace_data *data, const char *xml);
 318
 319 /* Parse a branch trace configuration xml document XML into CONF.  */
 320 extern void parse_xml_btrace_conf (struct btrace_config *conf, const char *xml);
 321
 322 /* Dereference a branch trace instruction iterator.  Return a pointer to the
 323    instruction the iterator points to.
 324    May return NULL if the iterator points to a gap in the trace.  */
 325 extern const struct btrace_insn *
 326   btrace_insn_get (const struct btrace_insn_iterator *);
 327
 328 /* Return the instruction number for a branch trace iterator.
 329    Returns one past the maximum instruction number for the end iterator.
 330    Returns zero if the iterator does not point to a valid instruction.  */
 331 extern unsigned int btrace_insn_number (const struct btrace_insn_iterator *);
 332
 333 /* Initialize a branch trace instruction iterator to point to the begin/end of
 334    the branch trace.  Throws an error if there is no branch trace.  */
 335 extern void btrace_insn_begin (struct btrace_insn_iterator *,
 336                                const struct btrace_thread_info *);
 337 extern void btrace_insn_end (struct btrace_insn_iterator *,
 338                              const struct btrace_thread_info *);
 339
 340 /* Increment/decrement a branch trace instruction iterator by at most STRIDE
 341    instructions.  Return the number of instructions by which the instruction
 342    iterator has been advanced.
 343    Returns zero, if the operation failed or STRIDE had been zero.  */
 344 extern unsigned int btrace_insn_next (struct btrace_insn_iterator *,
 345                                       unsigned int stride);
 346 extern unsigned int btrace_insn_prev (struct btrace_insn_iterator *,
 347                                       unsigned int stride);
 348
 349 /* Compare two branch trace instruction iterators.
 350    Return a negative number if LHS < RHS.
 351    Return zero if LHS == RHS.
 352    Return a positive number if LHS > RHS.  */
 353 extern int btrace_insn_cmp (const struct btrace_insn_iterator *lhs,
 354                             const struct btrace_insn_iterator *rhs);
 355
 356 /* Find an instruction in the function branch trace by its number.
 357    If the instruction is found, initialize the branch trace instruction
 358    iterator to point to this instruction and return non-zero.
 359    Return zero otherwise.  */
 360 extern int btrace_find_insn_by_number (struct btrace_insn_iterator *,
 361                                        const struct btrace_thread_info *,
 362                                        unsigned int number);
 363
 364 /* Dereference a branch trace call iterator.  Return a pointer to the
 365    function the iterator points to or NULL if the interator points past
 366    the end of the branch trace.  */
 367 extern const struct btrace_function *
 368   btrace_call_get (const struct btrace_call_iterator *);
 369
 370 /* Return the function number for a branch trace call iterator.
 371    Returns one past the maximum function number for the end iterator.
 372    Returns zero if the iterator does not point to a valid function.  */
 373 extern unsigned int btrace_call_number (const struct btrace_call_iterator *);
 374
 375 /* Initialize a branch trace call iterator to point to the begin/end of
 376    the branch trace.  Throws an error if there is no branch trace.  */
 377 extern void btrace_call_begin (struct btrace_call_iterator *,
 378                                const struct btrace_thread_info *);
 379 extern void btrace_call_end (struct btrace_call_iterator *,
 380                              const struct btrace_thread_info *);
 381
 382 /* Increment/decrement a branch trace call iterator by at most STRIDE function
 383    segments.  Return the number of function segments by which the call
 384    iterator has been advanced.
 385    Returns zero, if the operation failed or STRIDE had been zero.  */
 386 extern unsigned int btrace_call_next (struct btrace_call_iterator *,
 387                                       unsigned int stride);
 388 extern unsigned int btrace_call_prev (struct btrace_call_iterator *,
 389                                       unsigned int stride);
 390
 391 /* Compare two branch trace call iterators.
 392    Return a negative number if LHS < RHS.
 393    Return zero if LHS == RHS.
 394    Return a positive number if LHS > RHS.  */
 395 extern int btrace_call_cmp (const struct btrace_call_iterator *lhs,
 396                             const struct btrace_call_iterator *rhs);
 397
 398 /* Find a function in the function branch trace by its NUMBER.
 399    If the function is found, initialize the branch trace call
 400    iterator to point to this function and return non-zero.
 401    Return zero otherwise.  */
 402 extern int btrace_find_call_by_number (struct btrace_call_iterator *,
 403                                        const struct btrace_thread_info *,
 404                                        unsigned int number);
 405
 406 /* Set the branch trace instruction history from BEGIN (inclusive) to
 407    END (exclusive).  */
 408 extern void btrace_set_insn_history (struct btrace_thread_info *,
 409                                      const struct btrace_insn_iterator *begin,
 410                                      const struct btrace_insn_iterator *end);
 411
 412 /* Set the branch trace function call history from BEGIN (inclusive) to
 413    END (exclusive).  */
 414 extern void btrace_set_call_history (struct btrace_thread_info *,
 415                                      const struct btrace_call_iterator *begin,
 416                                      const struct btrace_call_iterator *end);
 417
 418 /* Determine if branch tracing is currently replaying TP.  */
 419 extern int btrace_is_replaying (struct thread_info *tp);
 420
 421 /* Return non-zero if the branch trace for TP is empty; zero otherwise.  */
 422 extern int btrace_is_empty (struct thread_info *tp);
 423
 424 /* Create a cleanup for DATA.  */
 425 extern struct cleanup *make_cleanup_btrace_data (struct btrace_data *data);
 426
 427 #endif /* BTRACE_H */