1 /* Handle JIT code generation in the inferior for GDB, the GNU Debugger.
3 Copyright (C) 2009, 2010, 2011 Free Software Foundation, Inc.
5 This file is part of GDB.
7 This program is free software; you can redistribute it and/or modify
8 it under the terms of the GNU General Public License as published by
9 the Free Software Foundation; either version 3 of the License, or
10 (at your option) any later version.
12 This program is distributed in the hope that it will be useful,
13 but WITHOUT ANY WARRANTY; without even the implied warranty of
14 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15 GNU General Public License for more details.
17 You should have received a copy of the GNU General Public License
18 along with this program. If not, see <http://www.gnu.org/licenses/>. */
23 #include "jit-reader.h"
24 #include "breakpoint.h"
34 #include "gdb-dlfcn.h"
37 static const char *jit_reader_dir = NULL;
39 static const struct objfile_data *jit_objfile_data;
41 static const char *const jit_break_name = "__jit_debug_register_code";
43 static const char *const jit_descriptor_name = "__jit_debug_descriptor";
45 static const struct inferior_data *jit_inferior_data = NULL;
47 static void jit_inferior_init (struct gdbarch *gdbarch);
49 /* Non-zero if we want to see trace of jit level stuff. */
51 static int jit_debug = 0;
54 show_jit_debug (struct ui_file *file, int from_tty,
55 struct cmd_list_element *c, const char *value)
57 fprintf_filtered (file, _("JIT debugging is %s.\n"), value);
66 /* Openning the file is a no-op. */
69 mem_bfd_iovec_open (struct bfd *abfd, void *open_closure)
74 /* Closing the file is just freeing the base/size pair on our side. */
77 mem_bfd_iovec_close (struct bfd *abfd, void *stream)
83 /* For reading the file, we just need to pass through to target_read_memory and
84 fix up the arguments and return values. */
87 mem_bfd_iovec_pread (struct bfd *abfd, void *stream, void *buf,
88 file_ptr nbytes, file_ptr offset)
91 struct target_buffer *buffer = (struct target_buffer *) stream;
93 /* If this read will read all of the file, limit it to just the rest. */
94 if (offset + nbytes > buffer->size)
95 nbytes = buffer->size - offset;
97 /* If there are no more bytes left, we've reached EOF. */
101 err = target_read_memory (buffer->base + offset, (gdb_byte *) buf, nbytes);
108 /* For statting the file, we only support the st_size attribute. */
111 mem_bfd_iovec_stat (struct bfd *abfd, void *stream, struct stat *sb)
113 struct target_buffer *buffer = (struct target_buffer*) stream;
115 sb->st_size = buffer->size;
119 /* One reader that has been loaded successfully, and can potentially be used to
122 static struct jit_reader
124 struct gdb_reader_funcs *functions;
126 } *loaded_jit_reader = NULL;
128 typedef struct gdb_reader_funcs * (reader_init_fn_type) (void);
129 static const char *reader_init_fn_sym = "gdb_init_reader";
131 /* Try to load FILE_NAME as a JIT debug info reader. */
133 static struct jit_reader *
134 jit_reader_load (const char *file_name)
137 reader_init_fn_type *init_fn;
138 struct jit_reader *new_reader = NULL;
139 struct gdb_reader_funcs *funcs = NULL;
140 struct cleanup *old_cleanups;
143 fprintf_unfiltered (gdb_stdlog, _("Opening shared object %s.\n"),
145 so = gdb_dlopen (file_name);
146 old_cleanups = make_cleanup_dlclose (so);
148 init_fn = gdb_dlsym (so, reader_init_fn_sym);
150 error (_("Could not locate initialization function: %s."),
153 if (gdb_dlsym (so, "plugin_is_GPL_compatible") == NULL)
154 error (_("Reader not GPL compatible."));
157 if (funcs->reader_version != GDB_READER_INTERFACE_VERSION)
158 error (_("Reader version does not match GDB version."));
160 new_reader = XZALLOC (struct jit_reader);
161 new_reader->functions = funcs;
162 new_reader->handle = so;
164 discard_cleanups (old_cleanups);
168 /* Provides the jit-reader-load command. */
171 jit_reader_load_command (char *args, int from_tty)
175 struct cleanup *prev_cleanup;
178 error (_("No reader name provided."));
180 if (loaded_jit_reader != NULL)
181 error (_("JIT reader already loaded. Run jit-reader-unload first."));
183 so_name = xstrprintf ("%s/%s", jit_reader_dir, args);
184 prev_cleanup = make_cleanup (xfree, so_name);
186 loaded_jit_reader = jit_reader_load (so_name);
187 do_cleanups (prev_cleanup);
190 /* Provides the jit-reader-unload command. */
193 jit_reader_unload_command (char *args, int from_tty)
195 if (!loaded_jit_reader)
196 error (_("No JIT reader loaded."));
198 loaded_jit_reader->functions->destroy (loaded_jit_reader->functions);
200 gdb_dlclose (loaded_jit_reader->handle);
201 xfree (loaded_jit_reader);
202 loaded_jit_reader = NULL;
205 /* Open a BFD from the target's memory. */
208 bfd_open_from_target_memory (CORE_ADDR addr, ULONGEST size, char *target)
210 const char *filename = xstrdup ("<in-memory>");
211 struct target_buffer *buffer = xmalloc (sizeof (struct target_buffer));
215 return bfd_openr_iovec (filename, target,
223 /* Per-inferior structure recording the addresses in the inferior. */
225 struct jit_inferior_data
227 CORE_ADDR breakpoint_addr; /* &__jit_debug_register_code() */
228 CORE_ADDR descriptor_addr; /* &__jit_debug_descriptor */
231 /* Return jit_inferior_data for current inferior. Allocate if not already
234 static struct jit_inferior_data *
235 get_jit_inferior_data (void)
237 struct inferior *inf;
238 struct jit_inferior_data *inf_data;
240 inf = current_inferior ();
241 inf_data = inferior_data (inf, jit_inferior_data);
242 if (inf_data == NULL)
244 inf_data = XZALLOC (struct jit_inferior_data);
245 set_inferior_data (inf, jit_inferior_data, inf_data);
252 jit_inferior_data_cleanup (struct inferior *inf, void *arg)
257 /* Helper function for reading the global JIT descriptor from remote
261 jit_read_descriptor (struct gdbarch *gdbarch,
262 struct jit_descriptor *descriptor,
263 CORE_ADDR descriptor_addr)
266 struct type *ptr_type;
270 enum bfd_endian byte_order = gdbarch_byte_order (gdbarch);
272 /* Figure out how big the descriptor is on the remote and how to read it. */
273 ptr_type = builtin_type (gdbarch)->builtin_data_ptr;
274 ptr_size = TYPE_LENGTH (ptr_type);
275 desc_size = 8 + 2 * ptr_size; /* Two 32-bit ints and two pointers. */
276 desc_buf = alloca (desc_size);
278 /* Read the descriptor. */
279 err = target_read_memory (descriptor_addr, desc_buf, desc_size);
281 error (_("Unable to read JIT descriptor from remote memory!"));
283 /* Fix the endianness to match the host. */
284 descriptor->version = extract_unsigned_integer (&desc_buf[0], 4, byte_order);
285 descriptor->action_flag =
286 extract_unsigned_integer (&desc_buf[4], 4, byte_order);
287 descriptor->relevant_entry = extract_typed_address (&desc_buf[8], ptr_type);
288 descriptor->first_entry =
289 extract_typed_address (&desc_buf[8 + ptr_size], ptr_type);
292 /* Helper function for reading a JITed code entry from remote memory. */
295 jit_read_code_entry (struct gdbarch *gdbarch,
296 CORE_ADDR code_addr, struct jit_code_entry *code_entry)
299 struct type *ptr_type;
304 enum bfd_endian byte_order = gdbarch_byte_order (gdbarch);
306 /* Figure out how big the entry is on the remote and how to read it. */
307 ptr_type = builtin_type (gdbarch)->builtin_data_ptr;
308 ptr_size = TYPE_LENGTH (ptr_type);
309 entry_size = 3 * ptr_size + 8; /* Three pointers and one 64-bit int. */
310 entry_buf = alloca (entry_size);
312 /* Read the entry. */
313 err = target_read_memory (code_addr, entry_buf, entry_size);
315 error (_("Unable to read JIT code entry from remote memory!"));
317 /* Fix the endianness to match the host. */
318 ptr_type = builtin_type (gdbarch)->builtin_data_ptr;
319 code_entry->next_entry = extract_typed_address (&entry_buf[0], ptr_type);
320 code_entry->prev_entry =
321 extract_typed_address (&entry_buf[ptr_size], ptr_type);
322 code_entry->symfile_addr =
323 extract_typed_address (&entry_buf[2 * ptr_size], ptr_type);
325 align_bytes = gdbarch_long_long_align_bit (gdbarch) / 8;
327 off = (off + (align_bytes - 1)) & ~(align_bytes - 1);
329 code_entry->symfile_size =
330 extract_unsigned_integer (&entry_buf[off], 8, byte_order);
333 /* This function registers code associated with a JIT code entry. It uses the
334 pointer and size pair in the entry to read the symbol file from the remote
335 and then calls symbol_file_add_from_local_memory to add it as though it were
336 a symbol file added by the user. */
339 jit_register_code (struct gdbarch *gdbarch,
340 CORE_ADDR entry_addr, struct jit_code_entry *code_entry)
343 struct section_addr_info *sai;
344 struct bfd_section *sec;
345 struct objfile *objfile;
346 struct cleanup *old_cleanups;
348 const struct bfd_arch_info *b;
349 CORE_ADDR *entry_addr_ptr;
352 fprintf_unfiltered (gdb_stdlog,
353 "jit_register_code, symfile_addr = %s, "
354 "symfile_size = %s\n",
355 paddress (gdbarch, code_entry->symfile_addr),
356 pulongest (code_entry->symfile_size));
358 nbfd = bfd_open_from_target_memory (code_entry->symfile_addr,
359 code_entry->symfile_size, gnutarget);
362 puts_unfiltered (_("Error opening JITed symbol file, ignoring it.\n"));
366 /* Check the format. NOTE: This initializes important data that GDB uses!
367 We would segfault later without this line. */
368 if (!bfd_check_format (nbfd, bfd_object))
370 printf_unfiltered (_("\
371 JITed symbol file is not an object file, ignoring it.\n"));
376 /* Check bfd arch. */
377 b = gdbarch_bfd_arch_info (gdbarch);
378 if (b->compatible (b, bfd_get_arch_info (nbfd)) != b)
379 warning (_("JITed object file architecture %s is not compatible "
380 "with target architecture %s."), bfd_get_arch_info
381 (nbfd)->printable_name, b->printable_name);
383 /* Read the section address information out of the symbol file. Since the
384 file is generated by the JIT at runtime, it should all of the absolute
385 addresses that we care about. */
386 sai = alloc_section_addr_info (bfd_count_sections (nbfd));
387 old_cleanups = make_cleanup_free_section_addr_info (sai);
389 for (sec = nbfd->sections; sec != NULL; sec = sec->next)
390 if ((bfd_get_section_flags (nbfd, sec) & (SEC_ALLOC|SEC_LOAD)) != 0)
392 /* We assume that these virtual addresses are absolute, and do not
393 treat them as offsets. */
394 sai->other[i].addr = bfd_get_section_vma (nbfd, sec);
395 sai->other[i].name = xstrdup (bfd_get_section_name (nbfd, sec));
396 sai->other[i].sectindex = sec->index;
400 /* This call takes ownership of NBFD. It does not take ownership of SAI. */
401 objfile = symbol_file_add_from_bfd (nbfd, 0, sai, OBJF_SHARED, NULL);
403 /* Remember a mapping from entry_addr to objfile. */
404 entry_addr_ptr = xmalloc (sizeof (CORE_ADDR));
405 *entry_addr_ptr = entry_addr;
406 set_objfile_data (objfile, jit_objfile_data, entry_addr_ptr);
408 do_cleanups (old_cleanups);
411 /* This function unregisters JITed code and frees the corresponding
415 jit_unregister_code (struct objfile *objfile)
417 free_objfile (objfile);
420 /* Look up the objfile with this code entry address. */
422 static struct objfile *
423 jit_find_objf_with_entry_addr (CORE_ADDR entry_addr)
425 struct objfile *objf;
426 CORE_ADDR *objf_entry_addr;
430 objf_entry_addr = (CORE_ADDR *) objfile_data (objf, jit_objfile_data);
431 if (objf_entry_addr != NULL && *objf_entry_addr == entry_addr)
437 /* (Re-)Initialize the jit breakpoint if necessary.
438 Return 0 on success. */
441 jit_breakpoint_re_set_internal (struct gdbarch *gdbarch,
442 struct jit_inferior_data *inf_data)
444 if (inf_data->breakpoint_addr == 0)
446 struct minimal_symbol *reg_symbol;
448 /* Lookup the registration symbol. If it is missing, then we assume
449 we are not attached to a JIT. */
450 reg_symbol = lookup_minimal_symbol (jit_break_name, NULL, NULL);
451 if (reg_symbol == NULL)
453 inf_data->breakpoint_addr = SYMBOL_VALUE_ADDRESS (reg_symbol);
454 if (inf_data->breakpoint_addr == 0)
457 /* If we have not read the jit descriptor yet (e.g. because the JITer
458 itself is in a shared library which just got loaded), do so now. */
459 if (inf_data->descriptor_addr == 0)
460 jit_inferior_init (gdbarch);
466 fprintf_unfiltered (gdb_stdlog,
467 "jit_breakpoint_re_set_internal, "
468 "breakpoint_addr = %s\n",
469 paddress (gdbarch, inf_data->breakpoint_addr));
471 /* Put a breakpoint in the registration symbol. */
472 create_jit_event_breakpoint (gdbarch, inf_data->breakpoint_addr);
477 /* Register any already created translations. */
480 jit_inferior_init (struct gdbarch *gdbarch)
482 struct jit_descriptor descriptor;
483 struct jit_code_entry cur_entry;
484 struct jit_inferior_data *inf_data;
485 CORE_ADDR cur_entry_addr;
488 fprintf_unfiltered (gdb_stdlog, "jit_inferior_init\n");
490 inf_data = get_jit_inferior_data ();
491 if (jit_breakpoint_re_set_internal (gdbarch, inf_data) != 0)
494 if (inf_data->descriptor_addr == 0)
496 struct minimal_symbol *desc_symbol;
498 /* Lookup the descriptor symbol and cache the addr. If it is
499 missing, we assume we are not attached to a JIT and return early. */
500 desc_symbol = lookup_minimal_symbol (jit_descriptor_name, NULL, NULL);
501 if (desc_symbol == NULL)
504 inf_data->descriptor_addr = SYMBOL_VALUE_ADDRESS (desc_symbol);
505 if (inf_data->descriptor_addr == 0)
510 fprintf_unfiltered (gdb_stdlog,
511 "jit_inferior_init, descriptor_addr = %s\n",
512 paddress (gdbarch, inf_data->descriptor_addr));
514 /* Read the descriptor so we can check the version number and load
515 any already JITed functions. */
516 jit_read_descriptor (gdbarch, &descriptor, inf_data->descriptor_addr);
518 /* Check that the version number agrees with that we support. */
519 if (descriptor.version != 1)
520 error (_("Unsupported JIT protocol version in descriptor!"));
522 /* If we've attached to a running program, we need to check the descriptor
523 to register any functions that were already generated. */
524 for (cur_entry_addr = descriptor.first_entry;
526 cur_entry_addr = cur_entry.next_entry)
528 jit_read_code_entry (gdbarch, cur_entry_addr, &cur_entry);
530 /* This hook may be called many times during setup, so make sure we don't
531 add the same symbol file twice. */
532 if (jit_find_objf_with_entry_addr (cur_entry_addr) != NULL)
535 jit_register_code (gdbarch, cur_entry_addr, &cur_entry);
539 /* Exported routine to call when an inferior has been created. */
542 jit_inferior_created_hook (void)
544 jit_inferior_init (target_gdbarch);
547 /* Exported routine to call to re-set the jit breakpoints,
548 e.g. when a program is rerun. */
551 jit_breakpoint_re_set (void)
553 jit_breakpoint_re_set_internal (target_gdbarch,
554 get_jit_inferior_data ());
557 /* Reset inferior_data, so sybols will be looked up again, and jit_breakpoint
561 jit_reset_inferior_data_and_breakpoints (void)
563 struct jit_inferior_data *inf_data;
565 /* Force jit_inferior_init to re-lookup of jit symbol addresses. */
566 inf_data = get_jit_inferior_data ();
567 inf_data->breakpoint_addr = 0;
568 inf_data->descriptor_addr = 0;
570 /* Remove any existing JIT breakpoint(s). */
571 remove_jit_event_breakpoints ();
573 jit_inferior_init (target_gdbarch);
576 /* Wrapper to match the observer function pointer prototype. */
579 jit_inferior_created_observer (struct target_ops *objfile, int from_tty)
581 jit_reset_inferior_data_and_breakpoints ();
584 /* This function cleans up any code entries left over when the
585 inferior exits. We get left over code when the inferior exits
586 without unregistering its code, for example when it crashes. */
589 jit_inferior_exit_hook (struct inferior *inf)
591 struct objfile *objf;
592 struct objfile *temp;
594 ALL_OBJFILES_SAFE (objf, temp)
595 if (objfile_data (objf, jit_objfile_data) != NULL)
596 jit_unregister_code (objf);
600 jit_executable_changed_observer (void)
602 jit_reset_inferior_data_and_breakpoints ();
606 jit_event_handler (struct gdbarch *gdbarch)
608 struct jit_descriptor descriptor;
609 struct jit_code_entry code_entry;
610 CORE_ADDR entry_addr;
611 struct objfile *objf;
613 /* Read the descriptor from remote memory. */
614 jit_read_descriptor (gdbarch, &descriptor,
615 get_jit_inferior_data ()->descriptor_addr);
616 entry_addr = descriptor.relevant_entry;
618 /* Do the corresponding action. */
619 switch (descriptor.action_flag)
624 jit_read_code_entry (gdbarch, entry_addr, &code_entry);
625 jit_register_code (gdbarch, entry_addr, &code_entry);
628 objf = jit_find_objf_with_entry_addr (entry_addr);
630 printf_unfiltered (_("Unable to find JITed code "
631 "entry at address: %s\n"),
632 paddress (gdbarch, entry_addr));
634 jit_unregister_code (objf);
638 error (_("Unknown action_flag value in JIT descriptor!"));
643 /* Provide a prototype to silence -Wmissing-prototypes. */
645 extern void _initialize_jit (void);
648 _initialize_jit (void)
650 jit_reader_dir = relocate_gdb_directory (JIT_READER_DIR,
651 JIT_READER_DIR_RELOCATABLE);
652 add_setshow_zinteger_cmd ("jit", class_maintenance, &jit_debug,
653 _("Set JIT debugging."),
654 _("Show JIT debugging."),
655 _("When non-zero, JIT debugging is enabled."),
658 &setdebuglist, &showdebuglist);
660 observer_attach_inferior_created (jit_inferior_created_observer);
661 observer_attach_inferior_exit (jit_inferior_exit_hook);
662 observer_attach_executable_changed (jit_executable_changed_observer);
663 jit_objfile_data = register_objfile_data ();
665 register_inferior_data_with_cleanup (jit_inferior_data_cleanup);
666 if (is_dl_available ())
668 add_com ("jit-reader-load", no_class, jit_reader_load_command, _("\
669 Load FILE as debug info reader and unwinder for JIT compiled code.\n\
670 Usage: jit-reader-load FILE\n\
671 Try to load file FILE as a debug info reader (and unwinder) for\n\
672 JIT compiled code. The file is loaded from " JIT_READER_DIR ",\n\
673 relocated relative to the GDB executable if required."));
674 add_com ("jit-reader-unload", no_class, jit_reader_unload_command, _("\
675 Unload the currently loaded JIT debug info reader.\n\
676 Usage: jit-reader-unload FILE\n\n\
677 Do \"help jit-reader-load\" for info on loading debug info readers."));