gdbsupport/btrace-common.h

   1 /* Branch trace support for GDB, the GNU debugger.
   2
   3    Copyright (C) 2013-2024 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 COMMON_BTRACE_COMMON_H
  23 #define COMMON_BTRACE_COMMON_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 /* A branch trace block.
  30
  31    This represents a block of sequential control-flow.  Adjacent blocks will be
  32    connected via calls, returns, or jumps.  The latter can be direct or
  33    indirect, conditional or unconditional.  Branches can further be
  34    asynchronous, e.g. interrupts.  */
  35 struct btrace_block
  36 {
  37   /* The address of the first byte of the first instruction in the block.
  38      The address may be zero if we do not know the beginning of this block,
  39      such as for the first block in a delta trace.  */
  40   CORE_ADDR begin;
  41
  42   /* The address of the first byte of the last instruction in the block.  */
  43   CORE_ADDR end;
  44
  45   /* Simple constructor.  */
  46   btrace_block (CORE_ADDR begin, CORE_ADDR end)
  47     : begin (begin),
  48       end (end)
  49   {
  50     /* Nothing.  */
  51   }
  52 };
  53
  54 /* Enumeration of btrace formats.  */
  55
  56 enum btrace_format
  57 {
  58   /* No branch trace format.  */
  59   BTRACE_FORMAT_NONE,
  60
  61   /* Branch trace is in Branch Trace Store (BTS) format.
  62      Actually, the format is a sequence of blocks derived from BTS.  */
  63   BTRACE_FORMAT_BTS,
  64
  65   /* Branch trace is in Intel Processor Trace format.  */
  66   BTRACE_FORMAT_PT
  67 };
  68
  69 /* An enumeration of cpu vendors.  */
  70
  71 enum btrace_cpu_vendor
  72 {
  73   /* We do not know this vendor.  */
  74   CV_UNKNOWN,
  75
  76   /* Intel.  */
  77   CV_INTEL,
  78
  79   /* AMD.  */
  80   CV_AMD
  81 };
  82
  83 /* A cpu identifier.  */
  84
  85 struct btrace_cpu
  86 {
  87   /* The processor vendor.  */
  88   enum btrace_cpu_vendor vendor;
  89
  90   /* The cpu family.  */
  91   unsigned short family;
  92
  93   /* The cpu model.  */
  94   unsigned char model;
  95
  96   /* The cpu stepping.  */
  97   unsigned char stepping;
  98 };
  99
 100 /* A BTS configuration.  */
 101
 102 struct btrace_config_bts
 103 {
 104   /* The size of the branch trace buffer in bytes.
 105
 106      This is unsigned int and not size_t since it is registered as
 107      control variable for "set record btrace bts buffer-size".  */
 108   unsigned int size;
 109 };
 110
 111 /* An Intel Processor Trace configuration.  */
 112
 113 struct btrace_config_pt
 114 {
 115   /* The size of the branch trace buffer in bytes.
 116
 117      This is unsigned int and not size_t since it is registered as
 118      control variable for "set record btrace pt buffer-size".  */
 119   unsigned int size;
 120 };
 121
 122 /* A branch tracing configuration.
 123
 124    This describes the requested configuration as well as the actually
 125    obtained configuration.
 126    We describe the configuration for all different formats so we can
 127    easily switch between formats.  */
 128
 129 struct btrace_config
 130 {
 131   /* The branch tracing format.  */
 132   enum btrace_format format;
 133
 134   /* The BTS format configuration.  */
 135   struct btrace_config_bts bts;
 136
 137   /* The Intel Processor Trace format configuration.  */
 138   struct btrace_config_pt pt;
 139 };
 140
 141 /* Branch trace in BTS format.  */
 142 struct btrace_data_bts
 143 {
 144   /* Branch trace is represented as a vector of branch trace blocks starting
 145      with the most recent block.  This needs to be a pointer as we place
 146      btrace_data_bts into a union.  */
 147   std::vector<btrace_block> *blocks;
 148 };
 149
 150 /* Configuration information to go with the trace data.  */
 151 struct btrace_data_pt_config
 152 {
 153   /* The processor on which the trace has been collected.  */
 154   struct btrace_cpu cpu;
 155 };
 156
 157 /* Branch trace in Intel Processor Trace format.  */
 158 struct btrace_data_pt
 159 {
 160   /* Some configuration information to go with the data.  */
 161   struct btrace_data_pt_config config;
 162
 163   /* The trace data.  */
 164   gdb_byte *data;
 165
 166   /* The size of DATA in bytes.  */
 167   size_t size;
 168 };
 169
 170 /* The branch trace data.  */
 171 struct btrace_data
 172 {
 173   btrace_data () = default;
 174
 175   ~btrace_data ()
 176   {
 177     fini ();
 178   }
 179
 180   btrace_data &operator= (btrace_data &&other)
 181   {
 182     if (this != &other)
 183       {
 184         fini ();
 185         format = other.format;
 186         variant = other.variant;
 187         other.format = BTRACE_FORMAT_NONE;
 188       }
 189     return *this;
 190   }
 191
 192   /* Return true if this is empty; false otherwise.  */
 193   bool empty () const;
 194
 195   /* Clear this object.  */
 196   void clear ();
 197
 198   enum btrace_format format = BTRACE_FORMAT_NONE;
 199
 200   union
 201   {
 202     /* Format == BTRACE_FORMAT_BTS.  */
 203     struct btrace_data_bts bts;
 204
 205     /* Format == BTRACE_FORMAT_PT.  */
 206     struct btrace_data_pt pt;
 207   } variant;
 208
 209 private:
 210
 211   DISABLE_COPY_AND_ASSIGN (btrace_data);
 212
 213   void fini ();
 214 };
 215
 216 /* Target specific branch trace information.  */
 217 struct btrace_target_info
 218 {
 219   btrace_target_info (ptid_t ptid) : ptid (ptid)
 220     {}
 221
 222   btrace_target_info (ptid_t ptid, btrace_config conf)
 223     : ptid (ptid), conf (conf)
 224     {}
 225
 226   virtual ~btrace_target_info () = default;
 227
 228   /* The ptid of this thread.  */
 229   ptid_t ptid {};
 230
 231   /* The obtained branch trace configuration.  */
 232   btrace_config conf {};
 233 };
 234
 235 /* Enumeration of btrace read types.  */
 236
 237 enum btrace_read_type
 238 {
 239   /* Send all available trace.  */
 240   BTRACE_READ_ALL,
 241
 242   /* Send all available trace, if it changed.  */
 243   BTRACE_READ_NEW,
 244
 245   /* Send the trace since the last request.  This will fail if the trace
 246      buffer overflowed.  */
 247   BTRACE_READ_DELTA
 248 };
 249
 250 /* Enumeration of btrace errors.  */
 251
 252 enum btrace_error
 253 {
 254   /* No error.  Everything is OK.  */
 255   BTRACE_ERR_NONE,
 256
 257   /* An unknown error.  */
 258   BTRACE_ERR_UNKNOWN,
 259
 260   /* Branch tracing is not supported on this system.  */
 261   BTRACE_ERR_NOT_SUPPORTED,
 262
 263   /* The branch trace buffer overflowed; no delta read possible.  */
 264   BTRACE_ERR_OVERFLOW
 265 };
 266
 267 /* Return a string representation of FORMAT.  */
 268 extern const char *btrace_format_string (enum btrace_format format);
 269
 270 /* Return an abbreviation string representation of FORMAT.  */
 271 extern const char *btrace_format_short_string (enum btrace_format format);
 272
 273 /* Append the branch trace data from SRC to the end of DST.
 274    Both SRC and DST must use the same format.
 275    Returns zero on success; a negative number otherwise.  */
 276 extern int btrace_data_append (struct btrace_data *dst,
 277                                const struct btrace_data *src);
 278
 279 #endif /* COMMON_BTRACE_COMMON_H */