gdb/dtrace-probe.c

   1 /* DTrace probe support for GDB.
   2
   3    Copyright (C) 2014-2015 Free Software Foundation, Inc.
   4
   5    Contributed by Oracle, Inc.
   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 #include "defs.h"
  23 #include "probe.h"
  24 #include "vec.h"
  25 #include "elf-bfd.h"
  26 #include "gdbtypes.h"
  27 #include "obstack.h"
  28 #include "objfiles.h"
  29 #include "complaints.h"
  30 #include "value.h"
  31 #include "ax.h"
  32 #include "ax-gdb.h"
  33 #include "language.h"
  34 #include "parser-defs.h"
  35 #include "inferior.h"
  36
  37 /* The type of the ELF sections where we will find the DOF programs
  38    with information about probes.  */
  39
  40 #ifndef SHT_SUNW_dof
  41 # define SHT_SUNW_dof   0x6ffffff4
  42 #endif
  43
  44 /* Forward declaration.  */
  45
  46 static const struct probe_ops dtrace_probe_ops;
  47
  48 /* The following structure represents a single argument for the
  49    probe.  */
  50
  51 struct dtrace_probe_arg
  52 {
  53   /* The type of the probe argument.  */
  54   struct type *type;
  55
  56   /* A string describing the type.  */
  57   char *type_str;
  58
  59   /* The argument converted to an internal GDB expression.  */
  60   struct expression *expr;
  61 };
  62
  63 typedef struct dtrace_probe_arg dtrace_probe_arg_s;
  64 DEF_VEC_O (dtrace_probe_arg_s);
  65
  66 /* The following structure represents an enabler for a probe.  */
  67
  68 struct dtrace_probe_enabler
  69 {
  70   /* Program counter where the is-enabled probe is installed.  The
  71      contents (nops, whatever...) stored at this address are
  72      architecture dependent.  */
  73   CORE_ADDR address;
  74 };
  75
  76 typedef struct dtrace_probe_enabler dtrace_probe_enabler_s;
  77 DEF_VEC_O (dtrace_probe_enabler_s);
  78
  79 /* The following structure represents a dtrace probe.  */
  80
  81 struct dtrace_probe
  82 {
  83   /* Generic information about the probe.  This must be the first
  84      element of this struct, in order to maintain binary compatibility
  85      with the `struct probe' and be able to fully abstract it.  */
  86   struct probe p;
  87
  88   /* A probe can have zero or more arguments.  */
  89   int probe_argc;
  90   VEC (dtrace_probe_arg_s) *args;
  91
  92   /* A probe can have zero or more "enablers" associated with it.  */
  93   VEC (dtrace_probe_enabler_s) *enablers;
  94
  95   /* Whether the expressions for the arguments have been built.  */
  96   unsigned int args_expr_built : 1;
  97 };
  98
  99 /* Implementation of the probe_is_linespec method.  */
 100
 101 static int
 102 dtrace_probe_is_linespec (const char **linespecp)
 103 {
 104   static const char *const keywords[] = { "-pdtrace", "-probe-dtrace", NULL };
 105
 106   return probe_is_linespec_by_keyword (linespecp, keywords);
 107 }
 108
 109 /* DOF programs can contain an arbitrary number of sections of 26
 110    different types.  In order to support DTrace USDT probes we only
 111    need to handle a subset of these section types, fortunately.  These
 112    section types are defined in the following enumeration.
 113
 114    See linux/dtrace/dof_defines.h for a complete list of section types
 115    along with their values.  */
 116
 117 enum dtrace_dof_sect_type
 118 {
 119   /* Null section.  */
 120   DTRACE_DOF_SECT_TYPE_NONE = 0,
 121   /* A dof_ecbdesc_t. */
 122   DTRACE_DOF_SECT_TYPE_ECBDESC = 3,
 123   /* A string table.  */
 124   DTRACE_DOF_SECT_TYPE_STRTAB = 8,
 125   /* A dof_provider_t  */
 126   DTRACE_DOF_SECT_TYPE_PROVIDER = 15,
 127   /* Array of dof_probe_t  */
 128   DTRACE_DOF_SECT_TYPE_PROBES = 16,
 129   /* An array of probe arg mappings.  */
 130   DTRACE_DOF_SECT_TYPE_PRARGS = 17,
 131   /* An array of probe arg offsets.  */
 132   DTRACE_DOF_SECT_TYPE_PROFFS = 18,
 133   /* An array of probe is-enabled offsets.  */
 134   DTRACE_DOF_SECT_TYPE_PRENOFFS = 26
 135 };
 136
 137 /* The following collection of data structures map the structure of
 138    DOF entities.  Again, we only cover the subset of DOF used to
 139    implement USDT probes.
 140
 141    See linux/dtrace/dof.h header for a complete list of data
 142    structures.  */
 143
 144 /* Offsets to index the dofh_ident[] array defined below.  */
 145
 146 enum dtrace_dof_ident
 147 {
 148   /* First byte of the magic number.  */
 149   DTRACE_DOF_ID_MAG0 = 0,
 150   /* Second byte of the magic number.  */
 151   DTRACE_DOF_ID_MAG1 = 1,
 152   /* Third byte of the magic number.  */
 153   DTRACE_DOF_ID_MAG2 = 2,
 154   /* Fourth byte of the magic number.  */
 155   DTRACE_DOF_ID_MAG3 = 3,
 156   /* An enum_dof_encoding value.  */
 157   DTRACE_DOF_ID_ENCODING = 5
 158 };
 159
 160 /* Possible values for dofh_ident[DOF_ID_ENCODING].  */
 161
 162 enum dtrace_dof_encoding
 163 {
 164   /* The DOF program is little-endian.  */
 165   DTRACE_DOF_ENCODE_LSB = 1,
 166   /* The DOF program is big-endian.  */
 167   DTRACE_DOF_ENCODE_MSB = 2
 168 };
 169
 170 /* A DOF header, which describes the contents of a DOF program: number
 171    of sections, size, etc.  */
 172
 173 struct dtrace_dof_hdr
 174 {
 175   /* Identification bytes (see above). */
 176   uint8_t dofh_ident[16];
 177   /* File attribute flags (if any). */
 178   uint32_t dofh_flags;
 179   /* Size of file header in bytes. */
 180   uint32_t dofh_hdrsize;
 181   /* Size of section header in bytes. */
 182   uint32_t dofh_secsize;
 183   /* Number of section headers. */
 184   uint32_t dofh_secnum;
 185   /* File offset of section headers. */
 186   uint64_t dofh_secoff;
 187   /* File size of loadable portion. */
 188   uint64_t dofh_loadsz;
 189   /* File size of entire DOF file. */
 190   uint64_t dofh_filesz;
 191   /* Reserved for future use. */
 192   uint64_t dofh_pad;
 193 };
 194
 195 /* A DOF section, whose contents depend on its type.  The several
 196    supported section types are described in the enum
 197    dtrace_dof_sect_type above.  */
 198
 199 struct dtrace_dof_sect
 200 {
 201   /* Section type (see the define above). */
 202   uint32_t dofs_type;
 203   /* Section data memory alignment. */
 204   uint32_t dofs_align;
 205   /* Section flags (if any). */
 206   uint32_t dofs_flags;
 207   /* Size of section entry (if table). */
 208   uint32_t dofs_entsize;
 209   /* DOF + offset points to the section data. */
 210   uint64_t dofs_offset;
 211   /* Size of section data in bytes.  */
 212   uint64_t dofs_size;
 213 };
 214
 215 /* A DOF provider, which is the provider of a probe.  */
 216
 217 struct dtrace_dof_provider
 218 {
 219   /* Link to a DTRACE_DOF_SECT_TYPE_STRTAB section. */
 220   uint32_t dofpv_strtab;
 221   /* Link to a DTRACE_DOF_SECT_TYPE_PROBES section. */
 222   uint32_t dofpv_probes;
 223   /* Link to a DTRACE_DOF_SECT_TYPE_PRARGS section. */
 224   uint32_t dofpv_prargs;
 225   /* Link to a DTRACE_DOF_SECT_TYPE_PROFFS section. */
 226   uint32_t dofpv_proffs;
 227   /* Provider name string. */
 228   uint32_t dofpv_name;
 229   /* Provider attributes. */
 230   uint32_t dofpv_provattr;
 231   /* Module attributes. */
 232   uint32_t dofpv_modattr;
 233   /* Function attributes. */
 234   uint32_t dofpv_funcattr;
 235   /* Name attributes. */
 236   uint32_t dofpv_nameattr;
 237   /* Args attributes. */
 238   uint32_t dofpv_argsattr;
 239   /* Link to a DTRACE_DOF_SECT_PRENOFFS section. */
 240   uint32_t dofpv_prenoffs;
 241 };
 242
 243 /* A set of DOF probes and is-enabled probes sharing a base address
 244    and several attributes.  The particular locations and attributes of
 245    each probe are maintained in arrays in several other DOF sections.
 246    See the comment in dtrace_process_dof_probe for details on how
 247    these attributes are stored.  */
 248
 249 struct dtrace_dof_probe
 250 {
 251   /* Probe base address or offset. */
 252   uint64_t dofpr_addr;
 253   /* Probe function string. */
 254   uint32_t dofpr_func;
 255   /* Probe name string. */
 256   uint32_t dofpr_name;
 257   /* Native argument type strings. */
 258   uint32_t dofpr_nargv;
 259   /* Translated argument type strings. */
 260   uint32_t dofpr_xargv;
 261   /* Index of first argument mapping. */
 262   uint32_t dofpr_argidx;
 263   /* Index of first offset entry. */
 264   uint32_t dofpr_offidx;
 265   /* Native argument count. */
 266   uint8_t  dofpr_nargc;
 267   /* Translated argument count. */
 268   uint8_t  dofpr_xargc;
 269   /* Number of offset entries for probe. */
 270   uint16_t dofpr_noffs;
 271   /* Index of first is-enabled offset. */
 272   uint32_t dofpr_enoffidx;
 273   /* Number of is-enabled offsets. */
 274   uint16_t dofpr_nenoffs;
 275   /* Reserved for future use. */
 276   uint16_t dofpr_pad1;
 277   /* Reserved for future use. */
 278   uint32_t dofpr_pad2;
 279 };
 280
 281 /* DOF supports two different encodings: MSB (big-endian) and LSB
 282    (little-endian).  The encoding is itself encoded in the DOF header.
 283    The following function returns an unsigned value in the host
 284    endianness.  */
 285
 286 #define DOF_UINT(dof, field)                                            \
 287   extract_unsigned_integer ((gdb_byte *) &(field),                      \
 288                             sizeof ((field)),                           \
 289                             (((dof)->dofh_ident[DTRACE_DOF_ID_ENCODING] \
 290                               == DTRACE_DOF_ENCODE_MSB)                 \
 291                              ? BFD_ENDIAN_BIG : BFD_ENDIAN_LITTLE))
 292
 293 /* The following macro applies a given byte offset to a DOF (a pointer
 294    to a dtrace_dof_hdr structure) and returns the resulting
 295    address.  */
 296
 297 #define DTRACE_DOF_PTR(dof, offset) (&((char *) (dof))[(offset)])
 298
 299 /* The following macro returns a pointer to the beginning of a given
 300    section in a DOF object.  The section is referred to by its index
 301    in the sections array.  */
 302
 303 #define DTRACE_DOF_SECT(dof, idx)                                       \
 304   ((struct dtrace_dof_sect *)                                           \
 305    DTRACE_DOF_PTR ((dof),                                               \
 306                    DOF_UINT ((dof), (dof)->dofh_secoff)                 \
 307                    + ((idx) * DOF_UINT ((dof), (dof)->dofh_secsize))))
 308
 309 /* Helper function to examine the probe described by the given PROBE
 310    and PROVIDER data structures and add it to the PROBESP vector.
 311    STRTAB, OFFTAB, EOFFTAB and ARGTAB are pointers to tables in the
 312    DOF program containing the attributes for the probe.  */
 313
 314 static void
 315 dtrace_process_dof_probe (struct objfile *objfile,
 316                           struct gdbarch *gdbarch, VEC (probe_p) **probesp,
 317                           struct dtrace_dof_hdr *dof,
 318                           struct dtrace_dof_probe *probe,
 319                           struct dtrace_dof_provider *provider,
 320                           char *strtab, char *offtab, char *eofftab,
 321                           char *argtab, uint64_t strtab_size)
 322 {
 323   int i, j, num_probes, num_enablers;
 324   struct cleanup *cleanup;
 325   VEC (dtrace_probe_enabler_s) *enablers;
 326   char *p;
 327
 328   /* Each probe section can define zero or more probes of two
 329      different types:
 330
 331      - probe->dofpr_noffs regular probes whose program counters are
 332        stored in 32bit words starting at probe->dofpr_addr +
 333        offtab[probe->dofpr_offidx].
 334
 335      - probe->dofpr_nenoffs is-enabled probes whose program counters
 336        are stored in 32bit words starting at probe->dofpr_addr +
 337        eofftab[probe->dofpr_enoffidx].
 338
 339      However is-enabled probes are not probes per-se, but an
 340      optimization hack that is implemented in the kernel in a very
 341      similar way than normal probes.  This is how we support
 342      is-enabled probes on GDB:
 343
 344      - Our probes are always DTrace regular probes.
 345
 346      - Our probes can be associated with zero or more "enablers".  The
 347        list of enablers is built from the is-enabled probes defined in
 348        the Probe section.
 349
 350      - Probes having a non-empty list of enablers can be enabled or
 351        disabled using the `enable probe' and `disable probe' commands
 352        respectively.  The `Enabled' column in the output of `info
 353        probes' will read `yes' if the enablers are activated, `no'
 354        otherwise.
 355
 356      - Probes having an empty list of enablers are always enabled.
 357        The `Enabled' column in the output of `info probes' will
 358        read `always'.
 359
 360      It follows that if there are DTrace is-enabled probes defined for
 361      some provider/name but no DTrace regular probes defined then the
 362      GDB user wont be able to enable/disable these conditionals.  */
 363
 364   num_probes = DOF_UINT (dof, probe->dofpr_noffs);
 365   if (num_probes == 0)
 366     return;
 367
 368   /* Build the list of enablers for the probes defined in this Probe
 369      DOF section.  */
 370   enablers = NULL;
 371   cleanup
 372     = make_cleanup (VEC_cleanup (dtrace_probe_enabler_s), &enablers);
 373   num_enablers = DOF_UINT (dof, probe->dofpr_nenoffs);
 374   for (i = 0; i < num_enablers; i++)
 375     {
 376       struct dtrace_probe_enabler enabler;
 377       uint32_t enabler_offset
 378         = ((uint32_t *) eofftab)[DOF_UINT (dof, probe->dofpr_enoffidx) + i];
 379
 380       enabler.address = DOF_UINT (dof, probe->dofpr_addr)
 381         + DOF_UINT (dof, enabler_offset);
 382       VEC_safe_push (dtrace_probe_enabler_s, enablers, &enabler);
 383     }
 384
 385   for (i = 0; i < num_probes; i++)
 386     {
 387       uint32_t probe_offset
 388         = ((uint32_t *) offtab)[DOF_UINT (dof, probe->dofpr_offidx) + i];
 389       struct dtrace_probe *ret
 390         = obstack_alloc (&objfile->per_bfd->storage_obstack, sizeof (*ret));
 391
 392       ret->p.pops = &dtrace_probe_ops;
 393       ret->p.arch = gdbarch;
 394       ret->args_expr_built = 0;
 395
 396       /* Set the provider and the name of the probe.  */
 397       ret->p.provider
 398         = xstrdup (strtab + DOF_UINT (dof, provider->dofpv_name));
 399       ret->p.name = xstrdup (strtab + DOF_UINT (dof, probe->dofpr_name));
 400
 401       /* The probe address.  */
 402       ret->p.address
 403         = DOF_UINT (dof, probe->dofpr_addr) + DOF_UINT (dof, probe_offset);
 404
 405       /* Number of arguments in the probe.  */
 406       ret->probe_argc = DOF_UINT (dof, probe->dofpr_nargc);
 407
 408       /* Store argument type descriptions.  A description of the type
 409          of the argument is in the (J+1)th null-terminated string
 410          starting at 'strtab' + 'probe->dofpr_nargv'.  */
 411       ret->args = NULL;
 412       p = strtab + DOF_UINT (dof, probe->dofpr_nargv);
 413       for (j = 0; j < ret->probe_argc; j++)
 414         {
 415           struct dtrace_probe_arg arg;
 416           struct expression *expr;
 417
 418           /* Set arg.expr to ensure all fields in expr are initialized and
 419              the compiler will not warn when arg is used.  */
 420           arg.expr = NULL;
 421           arg.type_str = xstrdup (p);
 422
 423           /* Use strtab_size as a sentinel.  */
 424           while (*p++ != '\0' && p - strtab < strtab_size);
 425
 426           /* Try to parse a type expression from the type string.  If
 427              this does not work then we set the type to `long
 428              int'.  */
 429           arg.type = builtin_type (gdbarch)->builtin_long;
 430           expr = parse_expression (arg.type_str);
 431           if (expr->elts[0].opcode == OP_TYPE)
 432             arg.type = expr->elts[1].type;
 433
 434           VEC_safe_push (dtrace_probe_arg_s, ret->args, &arg);
 435         }
 436
 437       /* Add the vector of enablers to this probe, if any.  */
 438       ret->enablers = VEC_copy (dtrace_probe_enabler_s, enablers);
 439
 440       /* Successfully created probe.  */
 441       VEC_safe_push (probe_p, *probesp, (struct probe *) ret);
 442     }
 443
 444   do_cleanups (cleanup);
 445 }
 446
 447 /* Helper function to collect the probes described in the DOF program
 448    whose header is pointed by DOF and add them to the PROBESP vector.
 449    SECT is the ELF section containing the DOF program and OBJFILE is
 450    its containing object file.  */
 451
 452 static void
 453 dtrace_process_dof (asection *sect, struct objfile *objfile,
 454                     VEC (probe_p) **probesp, struct dtrace_dof_hdr *dof)
 455 {
 456   bfd *abfd = objfile->obfd;
 457   int size = bfd_get_arch_size (abfd) / 8;
 458   struct gdbarch *gdbarch = get_objfile_arch (objfile);
 459   struct dtrace_dof_sect *section;
 460   int i;
 461
 462   /* The first step is to check for the DOF magic number.  If no valid
 463      DOF data is found in the section then a complaint is issued to
 464      the user and the section skipped.  */
 465   if (dof->dofh_ident[DTRACE_DOF_ID_MAG0] != 0x7F
 466       || dof->dofh_ident[DTRACE_DOF_ID_MAG1] != 'D'
 467       || dof->dofh_ident[DTRACE_DOF_ID_MAG2] != 'O'
 468       || dof->dofh_ident[DTRACE_DOF_ID_MAG3] != 'F')
 469     goto invalid_dof_data;
 470
 471   /* Make sure the encoding mark is either DTRACE_DOF_ENCODE_LSB or
 472      DTRACE_DOF_ENCODE_MSB.  */
 473   if (dof->dofh_ident[DTRACE_DOF_ID_ENCODING] != DTRACE_DOF_ENCODE_LSB
 474       && dof->dofh_ident[DTRACE_DOF_ID_ENCODING] != DTRACE_DOF_ENCODE_MSB)
 475     goto invalid_dof_data;
 476
 477   /* Make sure this DOF is not an enabling DOF, i.e. there are no ECB
 478      Description sections.  */
 479   section = (struct dtrace_dof_sect *) DTRACE_DOF_PTR (dof,
 480                                                        DOF_UINT (dof, dof->dofh_secoff));
 481   for (i = 0; i < DOF_UINT (dof, dof->dofh_secnum); i++, section++)
 482     if (section->dofs_type == DTRACE_DOF_SECT_TYPE_ECBDESC)
 483       return;
 484
 485   /* Iterate over any section of type Provider and extract the probe
 486      information from them.  If there are no "provider" sections on
 487      the DOF then we just return.  */
 488   section = (struct dtrace_dof_sect *) DTRACE_DOF_PTR (dof,
 489                                                        DOF_UINT (dof, dof->dofh_secoff));
 490   for (i = 0; i < DOF_UINT (dof, dof->dofh_secnum); i++, section++)
 491     if (DOF_UINT (dof, section->dofs_type) == DTRACE_DOF_SECT_TYPE_PROVIDER)
 492       {
 493         struct dtrace_dof_provider *provider = (struct dtrace_dof_provider *)
 494           DTRACE_DOF_PTR (dof, DOF_UINT (dof, section->dofs_offset));
 495         struct dtrace_dof_sect *strtab_s
 496           = DTRACE_DOF_SECT (dof, DOF_UINT (dof, provider->dofpv_strtab));
 497         struct dtrace_dof_sect *probes_s
 498           = DTRACE_DOF_SECT (dof, DOF_UINT (dof, provider->dofpv_probes));
 499         struct dtrace_dof_sect *args_s
 500           = DTRACE_DOF_SECT (dof, DOF_UINT (dof, provider->dofpv_prargs));
 501         struct dtrace_dof_sect *offsets_s
 502           = DTRACE_DOF_SECT (dof, DOF_UINT (dof, provider->dofpv_proffs));
 503         struct dtrace_dof_sect *eoffsets_s
 504           = DTRACE_DOF_SECT (dof, DOF_UINT (dof, provider->dofpv_prenoffs));
 505         char *strtab  = DTRACE_DOF_PTR (dof, DOF_UINT (dof, strtab_s->dofs_offset));
 506         char *offtab  = DTRACE_DOF_PTR (dof, DOF_UINT (dof, offsets_s->dofs_offset));
 507         char *eofftab = DTRACE_DOF_PTR (dof, DOF_UINT (dof, eoffsets_s->dofs_offset));
 508         char *argtab  = DTRACE_DOF_PTR (dof, DOF_UINT (dof, args_s->dofs_offset));
 509         unsigned int entsize = DOF_UINT (dof, probes_s->dofs_entsize);
 510         int num_probes;
 511
 512         /* Very, unlikely, but could crash gdb if not handled
 513            properly.  */
 514         if (entsize == 0)
 515           goto invalid_dof_data;
 516
 517         num_probes = DOF_UINT (dof, probes_s->dofs_size) / entsize;
 518
 519         for (i = 0; i < num_probes; i++)
 520           {
 521             struct dtrace_dof_probe *probe = (struct dtrace_dof_probe *)
 522               DTRACE_DOF_PTR (dof, DOF_UINT (dof, probes_s->dofs_offset)
 523                               + (i * DOF_UINT (dof, probes_s->dofs_entsize)));
 524
 525             dtrace_process_dof_probe (objfile,
 526                                       gdbarch, probesp,
 527                                       dof, probe,
 528                                       provider, strtab, offtab, eofftab, argtab,
 529                                       DOF_UINT (dof, strtab_s->dofs_size));
 530           }
 531       }
 532
 533   return;
 534
 535  invalid_dof_data:
 536   complaint (&symfile_complaints,
 537              _("skipping section '%s' which does not contain valid DOF data."),
 538              sect->name);
 539 }
 540
 541 /* Helper function to build the GDB internal expressiosn that, once
 542    evaluated, will calculate the values of the arguments of a given
 543    PROBE.  */
 544
 545 static void
 546 dtrace_build_arg_exprs (struct dtrace_probe *probe,
 547                         struct gdbarch *gdbarch)
 548 {
 549   struct parser_state pstate;
 550   struct dtrace_probe_arg *arg;
 551   int i;
 552
 553   probe->args_expr_built = 1;
 554
 555   /* Iterate over the arguments in the probe and build the
 556      corresponding GDB internal expression that will generate the
 557      value of the argument when executed at the PC of the probe.  */
 558   for (i = 0; i < probe->probe_argc; i++)
 559     {
 560       struct cleanup *back_to;
 561
 562       arg = VEC_index (dtrace_probe_arg_s, probe->args, i);
 563
 564       /* Initialize the expression buffer in the parser state.  The
 565          language does not matter, since we are using our own
 566          parser.  */
 567       initialize_expout (&pstate, 10, current_language, gdbarch);
 568       back_to = make_cleanup (free_current_contents, &pstate.expout);
 569
 570       /* The argument value, which is ABI dependent and casted to
 571          `long int'.  */
 572       gdbarch_dtrace_parse_probe_argument (gdbarch, &pstate, i);
 573
 574       discard_cleanups (back_to);
 575
 576       /* Casting to the expected type, but only if the type was
 577          recognized at probe load time.  Otherwise the argument will
 578          be evaluated as the long integer passed to the probe.  */
 579       if (arg->type != NULL)
 580         {
 581           write_exp_elt_opcode (&pstate, UNOP_CAST);
 582           write_exp_elt_type (&pstate, arg->type);
 583           write_exp_elt_opcode (&pstate, UNOP_CAST);
 584         }
 585
 586       reallocate_expout (&pstate);
 587       arg->expr = pstate.expout;
 588       prefixify_expression (arg->expr);
 589     }
 590 }
 591
 592 /* Helper function to return the Nth argument of a given PROBE.  */
 593
 594 static struct dtrace_probe_arg *
 595 dtrace_get_arg (struct dtrace_probe *probe, unsigned n,
 596                 struct gdbarch *gdbarch)
 597 {
 598   if (!probe->args_expr_built)
 599     dtrace_build_arg_exprs (probe, gdbarch);
 600
 601   return VEC_index (dtrace_probe_arg_s, probe->args, n);
 602 }
 603
 604 /* Implementation of the get_probes method.  */
 605
 606 static void
 607 dtrace_get_probes (VEC (probe_p) **probesp, struct objfile *objfile)
 608 {
 609   bfd *abfd = objfile->obfd;
 610   asection *sect = NULL;
 611
 612   /* Do nothing in case this is a .debug file, instead of the objfile
 613      itself.  */
 614   if (objfile->separate_debug_objfile_backlink != NULL)
 615     return;
 616
 617   /* Iterate over the sections in OBJFILE looking for DTrace
 618      information.  */
 619   for (sect = abfd->sections; sect != NULL; sect = sect->next)
 620     {
 621       if (elf_section_data (sect)->this_hdr.sh_type == SHT_SUNW_dof)
 622         {
 623           bfd_byte *dof;
 624
 625           /* Read the contents of the DOF section and then process it to
 626              extract the information of any probe defined into it.  */
 627           if (!bfd_malloc_and_get_section (abfd, sect, &dof))
 628             complaint (&symfile_complaints,
 629                        _("could not obtain the contents of"
 630                          "section '%s' in objfile `%s'."),
 631                        sect->name, abfd->filename);
 632
 633           dtrace_process_dof (sect, objfile, probesp,
 634                               (struct dtrace_dof_hdr *) dof);
 635           xfree (dof);
 636         }
 637     }
 638 }
 639
 640 /* Helper function to determine whether a given probe is "enabled" or
 641    "disabled".  A disabled probe is a probe in which one or more
 642    enablers are disabled.  */
 643
 644 static int
 645 dtrace_probe_is_enabled (struct dtrace_probe *probe)
 646 {
 647   int i;
 648   struct gdbarch *gdbarch = probe->p.arch;
 649   struct dtrace_probe_enabler *enabler;
 650
 651   for (i = 0;
 652        VEC_iterate (dtrace_probe_enabler_s, probe->enablers, i, enabler);
 653        i++)
 654     if (!gdbarch_dtrace_probe_is_enabled (gdbarch, enabler->address))
 655       return 0;
 656
 657   return 1;
 658 }
 659
 660 /* Implementation of the get_probe_address method.  */
 661
 662 static CORE_ADDR
 663 dtrace_get_probe_address (struct probe *probe, struct objfile *objfile)
 664 {
 665   gdb_assert (probe->pops == &dtrace_probe_ops);
 666   return probe->address + ANOFFSET (objfile->section_offsets,
 667                                     SECT_OFF_DATA (objfile));
 668 }
 669
 670 /* Implementation of the get_probe_argument_count method.  */
 671
 672 static unsigned
 673 dtrace_get_probe_argument_count (struct probe *probe_generic,
 674                                  struct frame_info *frame)
 675 {
 676   struct dtrace_probe *dtrace_probe = (struct dtrace_probe *) probe_generic;
 677
 678   gdb_assert (probe_generic->pops == &dtrace_probe_ops);
 679
 680   return dtrace_probe->probe_argc;
 681 }
 682
 683 /* Implementation of the can_evaluate_probe_arguments method.  */
 684
 685 static int
 686 dtrace_can_evaluate_probe_arguments (struct probe *probe_generic)
 687 {
 688   struct gdbarch *gdbarch = probe_generic->arch;
 689
 690   gdb_assert (probe_generic->pops == &dtrace_probe_ops);
 691   return gdbarch_dtrace_parse_probe_argument_p (gdbarch);
 692 }
 693
 694 /* Implementation of the evaluate_probe_argument method.  */
 695
 696 static struct value *
 697 dtrace_evaluate_probe_argument (struct probe *probe_generic, unsigned n,
 698                                 struct frame_info *frame)
 699 {
 700   struct gdbarch *gdbarch = probe_generic->arch;
 701   struct dtrace_probe *dtrace_probe = (struct dtrace_probe *) probe_generic;
 702   struct dtrace_probe_arg *arg;
 703   int pos = 0;
 704
 705   gdb_assert (probe_generic->pops == &dtrace_probe_ops);
 706
 707   arg = dtrace_get_arg (dtrace_probe, n, gdbarch);
 708   return evaluate_subexp_standard (arg->type, arg->expr, &pos, EVAL_NORMAL);
 709 }
 710
 711 /* Implementation of the compile_to_ax method.  */
 712
 713 static void
 714 dtrace_compile_to_ax (struct probe *probe_generic, struct agent_expr *expr,
 715                       struct axs_value *value, unsigned n)
 716 {
 717   struct dtrace_probe *dtrace_probe = (struct dtrace_probe *) probe_generic;
 718   struct dtrace_probe_arg *arg;
 719   union exp_element *pc;
 720
 721   gdb_assert (probe_generic->pops == &dtrace_probe_ops);
 722
 723   arg = dtrace_get_arg (dtrace_probe, n, expr->gdbarch);
 724
 725   pc = arg->expr->elts;
 726   gen_expr (arg->expr, &pc, expr, value);
 727
 728   require_rvalue (expr, value);
 729   value->type = arg->type;
 730 }
 731
 732 /* Implementation of the probe_destroy method.  */
 733
 734 static void
 735 dtrace_probe_destroy (struct probe *probe_generic)
 736 {
 737   struct dtrace_probe *probe = (struct dtrace_probe *) probe_generic;
 738   struct dtrace_probe_arg *arg;
 739   int i;
 740
 741   gdb_assert (probe_generic->pops == &dtrace_probe_ops);
 742
 743   for (i = 0; VEC_iterate (dtrace_probe_arg_s, probe->args, i, arg); i++)
 744     {
 745       xfree (arg->type_str);
 746       xfree (arg->expr);
 747     }
 748
 749   VEC_free (dtrace_probe_enabler_s, probe->enablers);
 750   VEC_free (dtrace_probe_arg_s, probe->args);
 751 }
 752
 753 /* Implementation of the type_name method.  */
 754
 755 static const char *
 756 dtrace_type_name (struct probe *probe_generic)
 757 {
 758   gdb_assert (probe_generic->pops == &dtrace_probe_ops);
 759   return "dtrace";
 760 }
 761
 762 /* Implementation of the gen_info_probes_table_header method.  */
 763
 764 static void
 765 dtrace_gen_info_probes_table_header (VEC (info_probe_column_s) **heads)
 766 {
 767   info_probe_column_s dtrace_probe_column;
 768
 769   dtrace_probe_column.field_name = "enabled";
 770   dtrace_probe_column.print_name = _("Enabled");
 771
 772   VEC_safe_push (info_probe_column_s, *heads, &dtrace_probe_column);
 773 }
 774
 775 /* Implementation of the gen_info_probes_table_values method.  */
 776
 777 static void
 778 dtrace_gen_info_probes_table_values (struct probe *probe_generic,
 779                                      VEC (const_char_ptr) **ret)
 780 {
 781   struct dtrace_probe *probe = (struct dtrace_probe *) probe_generic;
 782   const char *val = NULL;
 783
 784   gdb_assert (probe_generic->pops == &dtrace_probe_ops);
 785
 786   if (VEC_empty (dtrace_probe_enabler_s, probe->enablers))
 787     val = "always";
 788   else if (!gdbarch_dtrace_probe_is_enabled_p (probe_generic->arch))
 789     val = "unknown";
 790   else if (dtrace_probe_is_enabled (probe))
 791     val = "yes";
 792   else
 793     val = "no";
 794
 795   VEC_safe_push (const_char_ptr, *ret, val);
 796 }
 797
 798 /* Implementation of the enable_probe method.  */
 799
 800 static void
 801 dtrace_enable_probe (struct probe *probe)
 802 {
 803   struct gdbarch *gdbarch = probe->arch;
 804   struct dtrace_probe *dtrace_probe = (struct dtrace_probe *) probe;
 805   struct dtrace_probe_enabler *enabler;
 806   int i;
 807
 808   gdb_assert (probe->pops == &dtrace_probe_ops);
 809
 810   /* Enabling a dtrace probe implies patching the text section of the
 811      running process, so make sure the inferior is indeed running.  */
 812   if (ptid_equal (inferior_ptid, null_ptid))
 813     error (_("No inferior running"));
 814
 815   /* Fast path.  */
 816   if (dtrace_probe_is_enabled (dtrace_probe))
 817     return;
 818
 819   /* Iterate over all defined enabler in the given probe and enable
 820      them all using the corresponding gdbarch hook.  */
 821
 822   for (i = 0;
 823        VEC_iterate (dtrace_probe_enabler_s, dtrace_probe->enablers, i, enabler);
 824        i++)
 825     if (gdbarch_dtrace_enable_probe_p (gdbarch))
 826       gdbarch_dtrace_enable_probe (gdbarch, enabler->address);
 827 }
 828
 829
 830 /* Implementation of the disable_probe method.  */
 831
 832 static void
 833 dtrace_disable_probe (struct probe *probe)
 834 {
 835   struct gdbarch *gdbarch = probe->arch;
 836   struct dtrace_probe *dtrace_probe = (struct dtrace_probe *) probe;
 837   struct dtrace_probe_enabler *enabler;
 838   int i;
 839
 840   gdb_assert (probe->pops == &dtrace_probe_ops);
 841
 842   /* Disabling a dtrace probe implies patching the text section of the
 843      running process, so make sure the inferior is indeed running.  */
 844   if (ptid_equal (inferior_ptid, null_ptid))
 845     error (_("No inferior running"));
 846
 847   /* Fast path.  */
 848   if (!dtrace_probe_is_enabled (dtrace_probe))
 849     return;
 850
 851   /* Are we trying to disable a probe that does not have any enabler
 852      associated?  */
 853   if (VEC_empty (dtrace_probe_enabler_s, dtrace_probe->enablers))
 854     error (_("Probe %s:%s cannot be disabled: no enablers."), probe->provider, probe->name);
 855
 856   /* Iterate over all defined enabler in the given probe and disable
 857      them all using the corresponding gdbarch hook.  */
 858
 859   for (i = 0;
 860        VEC_iterate (dtrace_probe_enabler_s, dtrace_probe->enablers, i, enabler);
 861        i++)
 862     if (gdbarch_dtrace_disable_probe_p (gdbarch))
 863       gdbarch_dtrace_disable_probe (gdbarch, enabler->address);
 864 }
 865
 866 /* DTrace probe_ops.  */
 867
 868 static const struct probe_ops dtrace_probe_ops =
 869 {
 870   dtrace_probe_is_linespec,
 871   dtrace_get_probes,
 872   dtrace_get_probe_address,
 873   dtrace_get_probe_argument_count,
 874   dtrace_can_evaluate_probe_arguments,
 875   dtrace_evaluate_probe_argument,
 876   dtrace_compile_to_ax,
 877   NULL, /* set_semaphore  */
 878   NULL, /* clear_semaphore  */
 879   dtrace_probe_destroy,
 880   dtrace_type_name,
 881   dtrace_gen_info_probes_table_header,
 882   dtrace_gen_info_probes_table_values,
 883   dtrace_enable_probe,
 884   dtrace_disable_probe
 885 };
 886
 887 /* Implementation of the `info probes dtrace' command.  */
 888
 889 static void
 890 info_probes_dtrace_command (char *arg, int from_tty)
 891 {
 892   info_probes_for_ops (arg, from_tty, &dtrace_probe_ops);
 893 }
 894
 895 void _initialize_dtrace_probe (void);
 896
 897 void
 898 _initialize_dtrace_probe (void)
 899 {
 900   VEC_safe_push (probe_ops_cp, all_probe_ops, &dtrace_probe_ops);
 901
 902   add_cmd ("dtrace", class_info, info_probes_dtrace_command,
 903            _("\
 904 Show information about DTrace static probes.\n\
 905 Usage: info probes dtrace [PROVIDER [NAME [OBJECT]]]\n\
 906 Each argument is a regular expression, used to select probes.\n\
 907 PROVIDER matches probe provider names.\n\
 908 NAME matches the probe names.\n\
 909 OBJECT matches the executable or shared library name."),
 910            info_probes_cmdlist_get ());
 911 }