gdb/btrace.h

   1 /* Branch trace support for GDB, the GNU debugger.
   2
   3    Copyright (C) 2013-2014 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 information per thread.
 157
 158    This represents the branch trace configuration as well as the entry point
 159    into the branch trace data.  For the latter, it also contains the index into
 160    an array of branch trace blocks used for iterating though the branch trace
 161    blocks of a thread.  */
 162 struct btrace_thread_info
 163 {
 164   /* The target branch trace information for this thread.
 165
 166      This contains the branch trace configuration as well as any
 167      target-specific information necessary for implementing branch tracing on
 168      the underlying architecture.  */
 169   struct btrace_target_info *target;
 170
 171   /* The current branch trace for this thread (both inclusive).
 172
 173      The last instruction of END is the current instruction, which is not
 174      part of the execution history.
 175      Both will be NULL if there is no branch trace available.  If there is
 176      branch trace available, both will be non-NULL.  */
 177   struct btrace_function *begin;
 178   struct btrace_function *end;
 179
 180   /* The function level offset.  When added to each function's LEVEL,
 181      this normalizes the function levels such that the smallest level
 182      becomes zero.  */
 183   int level;
 184
 185   /* The instruction history iterator.  */
 186   struct btrace_insn_history *insn_history;
 187
 188   /* The function call history iterator.  */
 189   struct btrace_call_history *call_history;
 190
 191   /* The current replay position.  NULL if not replaying.  */
 192   struct btrace_insn_iterator *replay;
 193 };
 194
 195 /* Enable branch tracing for a thread.  */
 196 extern void btrace_enable (struct thread_info *tp);
 197
 198 /* Disable branch tracing for a thread.
 199    This will also delete the current branch trace data.  */
 200 extern void btrace_disable (struct thread_info *);
 201
 202 /* Disable branch tracing for a thread during teardown.
 203    This is similar to btrace_disable, except that it will use
 204    target_teardown_btrace instead of target_disable_btrace.  */
 205 extern void btrace_teardown (struct thread_info *);
 206
 207 /* Fetch the branch trace for a single thread.  */
 208 extern void btrace_fetch (struct thread_info *);
 209
 210 /* Clear the branch trace for a single thread.  */
 211 extern void btrace_clear (struct thread_info *);
 212
 213 /* Clear the branch trace for all threads when an object file goes away.  */
 214 extern void btrace_free_objfile (struct objfile *);
 215
 216 /* Parse a branch trace xml document into a block vector.  */
 217 extern VEC (btrace_block_s) *parse_xml_btrace (const char*);
 218
 219 /* Dereference a branch trace instruction iterator.  Return a pointer to the
 220    instruction the iterator points to.  */
 221 extern const struct btrace_insn *
 222   btrace_insn_get (const struct btrace_insn_iterator *);
 223
 224 /* Return the instruction number for a branch trace iterator.
 225    Returns one past the maximum instruction number for the end iterator.
 226    Returns zero if the iterator does not point to a valid instruction.  */
 227 extern unsigned int btrace_insn_number (const struct btrace_insn_iterator *);
 228
 229 /* Initialize a branch trace instruction iterator to point to the begin/end of
 230    the branch trace.  Throws an error if there is no branch trace.  */
 231 extern void btrace_insn_begin (struct btrace_insn_iterator *,
 232                                const struct btrace_thread_info *);
 233 extern void btrace_insn_end (struct btrace_insn_iterator *,
 234                              const struct btrace_thread_info *);
 235
 236 /* Increment/decrement a branch trace instruction iterator by at most STRIDE
 237    instructions.  Return the number of instructions by which the instruction
 238    iterator has been advanced.
 239    Returns zero, if the operation failed or STRIDE had been zero.  */
 240 extern unsigned int btrace_insn_next (struct btrace_insn_iterator *,
 241                                       unsigned int stride);
 242 extern unsigned int btrace_insn_prev (struct btrace_insn_iterator *,
 243                                       unsigned int stride);
 244
 245 /* Compare two branch trace instruction iterators.
 246    Return a negative number if LHS < RHS.
 247    Return zero if LHS == RHS.
 248    Return a positive number if LHS > RHS.  */
 249 extern int btrace_insn_cmp (const struct btrace_insn_iterator *lhs,
 250                             const struct btrace_insn_iterator *rhs);
 251
 252 /* Find an instruction in the function branch trace by its number.
 253    If the instruction is found, initialize the branch trace instruction
 254    iterator to point to this instruction and return non-zero.
 255    Return zero otherwise.  */
 256 extern int btrace_find_insn_by_number (struct btrace_insn_iterator *,
 257                                        const struct btrace_thread_info *,
 258                                        unsigned int number);
 259
 260 /* Dereference a branch trace call iterator.  Return a pointer to the
 261    function the iterator points to or NULL if the interator points past
 262    the end of the branch trace.  */
 263 extern const struct btrace_function *
 264   btrace_call_get (const struct btrace_call_iterator *);
 265
 266 /* Return the function number for a branch trace call iterator.
 267    Returns one past the maximum function number for the end iterator.
 268    Returns zero if the iterator does not point to a valid function.  */
 269 extern unsigned int btrace_call_number (const struct btrace_call_iterator *);
 270
 271 /* Initialize a branch trace call iterator to point to the begin/end of
 272    the branch trace.  Throws an error if there is no branch trace.  */
 273 extern void btrace_call_begin (struct btrace_call_iterator *,
 274                                const struct btrace_thread_info *);
 275 extern void btrace_call_end (struct btrace_call_iterator *,
 276                              const struct btrace_thread_info *);
 277
 278 /* Increment/decrement a branch trace call iterator by at most STRIDE function
 279    segments.  Return the number of function segments by which the call
 280    iterator has been advanced.
 281    Returns zero, if the operation failed or STRIDE had been zero.  */
 282 extern unsigned int btrace_call_next (struct btrace_call_iterator *,
 283                                       unsigned int stride);
 284 extern unsigned int btrace_call_prev (struct btrace_call_iterator *,
 285                                       unsigned int stride);
 286
 287 /* Compare two branch trace call iterators.
 288    Return a negative number if LHS < RHS.
 289    Return zero if LHS == RHS.
 290    Return a positive number if LHS > RHS.  */
 291 extern int btrace_call_cmp (const struct btrace_call_iterator *lhs,
 292                             const struct btrace_call_iterator *rhs);
 293
 294 /* Find a function in the function branch trace by its NUMBER.
 295    If the function is found, initialize the branch trace call
 296    iterator to point to this function and return non-zero.
 297    Return zero otherwise.  */
 298 extern int btrace_find_call_by_number (struct btrace_call_iterator *,
 299                                        const struct btrace_thread_info *,
 300                                        unsigned int number);
 301
 302 /* Set the branch trace instruction history from BEGIN (inclusive) to
 303    END (exclusive).  */
 304 extern void btrace_set_insn_history (struct btrace_thread_info *,
 305                                      const struct btrace_insn_iterator *begin,
 306                                      const struct btrace_insn_iterator *end);
 307
 308 /* Set the branch trace function call history from BEGIN (inclusive) to
 309    END (exclusive).  */
 310 extern void btrace_set_call_history (struct btrace_thread_info *,
 311                                      const struct btrace_call_iterator *begin,
 312                                      const struct btrace_call_iterator *end);
 313
 314 /* Determine if branch tracing is currently replaying TP.  */
 315 extern int btrace_is_replaying (struct thread_info *tp);
 316
 317 /* Return non-zero if the branch trace for TP is empty; zero otherwise.  */
 318 extern int btrace_is_empty (struct thread_info *tp);
 319
 320
 321 #endif /* BTRACE_H */