* NEWS: Announce JIT interface.
* Makefile.in (SFILES): Add jit.c.
(HFILES_NO_SRCDIR): Add jit.h.
(COMMON_OBS): Add jit.o.
* jit.c: New file.
* jit.h: New file.
* breakpoint.h (enum bptype): Add bp_jit_event to enum.
* breakpoint.c:
(update_breakpoints_after_exec): Delete jit breakpoints after exec.
(bpstat_what): Update event table for bp_jit_event.
(print_it_typical): Added case for bp_jit_event.
(print_one_breakpoint_location): Added case for bp_jit_event.
(allocate_bp_location): Added case for bp_jit_event.
(mention): Added case for bp_jit_event.
(delete_command): Added case for bp_jit_event.
(breakpoint_re_set_one): Added case for bp_jit_event.
(breakpoint_re_set): Added call to jit_inferior_created_hook.
(create_jit_event_breakpoint): New.
* infrun.c (handle_inferior_event): Add handler for jit event.
(follow_exec): Add call to jit_inferior_created_hook.
* doc/gdb.texinfo: Add chapter on JIT interface.
+2009-07-24 Reid Kleckner <reid@kleckner.net>
+
+ Add interface for JIT code generation.
+ * NEWS: Announce JIT interface.
+ * Makefile.in (SFILES): Add jit.c.
+ (HFILES_NO_SRCDIR): Add jit.h.
+ (COMMON_OBS): Add jit.o.
+ * jit.c: New file.
+ * jit.h: New file.
+ * breakpoint.h (enum bptype): Add bp_jit_event to enum.
+ * breakpoint.c:
+ (update_breakpoints_after_exec): Delete jit breakpoints after exec.
+ (bpstat_what): Update event table for bp_jit_event.
+ (print_it_typical): Added case for bp_jit_event.
+ (print_one_breakpoint_location): Added case for bp_jit_event.
+ (allocate_bp_location): Added case for bp_jit_event.
+ (mention): Added case for bp_jit_event.
+ (delete_command): Added case for bp_jit_event.
+ (breakpoint_re_set_one): Added case for bp_jit_event.
+ (breakpoint_re_set): Added call to jit_inferior_created_hook.
+ (create_jit_event_breakpoint): New.
+ * infrun.c (handle_inferior_event): Add handler for jit event.
+ (follow_exec): Add call to jit_inferior_created_hook.
+
2009-08-19 Ulrich Weigand <uweigand@de.ibm.com>
* value.c (enum internalvar_kind): Replace INTERNALVAR_SCALAR by
wrapper.c \
xml-tdesc.c xml-support.c \
inferior.c gdb_usleep.c \
- record.c
+ record.c \
+ jit.c
LINTFILES = $(SFILES) $(YYFILES) $(CONFIG_SRCS) init.c
annotate.h sim-regno.h dictionary.h dfp.h main.h frame-unwind.h \
remote-fileio.h i386-linux-tdep.h vax-tdep.h objc-lang.h \
sentinel-frame.h bcache.h symfile.h windows-tdep.h linux-tdep.h \
-gdb_usleep.h
+gdb_usleep.h jit.h
# Header files that already have srcdir in them, or which are in objdir.
solib.o solib-null.o \
prologue-value.o memory-map.o xml-support.o \
target-descriptions.o target-memory.o xml-tdesc.o xml-builtin.o \
- inferior.o osdata.o gdb_usleep.o record.o
+ inferior.o osdata.o gdb_usleep.o record.o \
+ jit.o
TSOBS = inflow.o
*** Changes since GDB 6.8
+* GDB now has an interface for JIT compilation. Applications that
+dynamically generate code can create symbol files in memory and register
+them with GDB. For users, the feature should work transparently, and
+for JIT developers, the interface is documented in the GDB manual in the
+"JIT Compilation Interface" chapter.
+
* Tracepoints may now be conditional. The syntax is as for
breakpoints; either an "if" clause appended to the "trace" command,
or the "condition" command is available. GDB sends the condition to
#include "top.h"
#include "wrapper.h"
#include "valprint.h"
+#include "jit.h"
/* readline include files */
#include "readline/readline.h"
continue;
}
+ /* JIT breakpoints must be explicitly reset after an exec(). */
+ if (b->type == bp_jit_event)
+ {
+ delete_breakpoint (b);
+ continue;
+ }
+
/* Thread event breakpoints must be set anew after an exec(),
as must overlay event and longjmp master breakpoints. */
if (b->type == bp_thread_event || b->type == bp_overlay_event
case bp_watchpoint_scope:
case bp_call_dummy:
case bp_tracepoint:
+ case bp_jit_event:
default:
result = PRINT_UNKNOWN;
break;
/* We hit the shared library event breakpoint. */
shlib_event,
+ /* We hit the jit event breakpoint. */
+ jit_event,
+
/* This is just used to count how many enums there are. */
class_last
};
#define clr BPSTAT_WHAT_CLEAR_LONGJMP_RESUME
#define sr BPSTAT_WHAT_STEP_RESUME
#define shl BPSTAT_WHAT_CHECK_SHLIBS
+#define jit BPSTAT_WHAT_CHECK_JIT
/* "Can't happen." Might want to print an error message.
abort() is not out of the question, but chances are GDB is just
back and decide something of a lower priority is better. The
ordering is:
- kc < clr sgl shl slr sn sr ss
- sgl < shl slr sn sr ss
- slr < err shl sn sr ss
- clr < err shl sn sr ss
- ss < shl sn sr
- sn < shl sr
+ kc < jit clr sgl shl slr sn sr ss
+ sgl < jit shl slr sn sr ss
+ slr < jit err shl sn sr ss
+ clr < jit err shl sn sr ss
+ ss < jit shl sn sr
+ sn < jit shl sr
+ jit < shl sr
shl < sr
sr <
table[(int) class_last][(int) BPSTAT_WHAT_LAST] =
{
/* old action */
- /* kc ss sn sgl slr clr sr shl
- */
-/*no_effect */
- {kc, ss, sn, sgl, slr, clr, sr, shl},
-/*wp_silent */
- {ss, ss, sn, ss, ss, ss, sr, shl},
-/*wp_noisy */
- {sn, sn, sn, sn, sn, sn, sr, shl},
-/*bp_nostop */
- {sgl, ss, sn, sgl, slr, slr, sr, shl},
-/*bp_silent */
- {ss, ss, sn, ss, ss, ss, sr, shl},
-/*bp_noisy */
- {sn, sn, sn, sn, sn, sn, sr, shl},
-/*long_jump */
- {slr, ss, sn, slr, slr, err, sr, shl},
-/*long_resume */
- {clr, ss, sn, err, err, err, sr, shl},
-/*step_resume */
- {sr, sr, sr, sr, sr, sr, sr, sr},
-/*shlib */
- {shl, shl, shl, shl, shl, shl, sr, shl}
+ /* kc ss sn sgl slr clr sr shl jit */
+/* no_effect */ {kc, ss, sn, sgl, slr, clr, sr, shl, jit},
+/* wp_silent */ {ss, ss, sn, ss, ss, ss, sr, shl, jit},
+/* wp_noisy */ {sn, sn, sn, sn, sn, sn, sr, shl, jit},
+/* bp_nostop */ {sgl, ss, sn, sgl, slr, slr, sr, shl, jit},
+/* bp_silent */ {ss, ss, sn, ss, ss, ss, sr, shl, jit},
+/* bp_noisy */ {sn, sn, sn, sn, sn, sn, sr, shl, jit},
+/* long_jump */ {slr, ss, sn, slr, slr, err, sr, shl, jit},
+/* long_resume */ {clr, ss, sn, err, err, err, sr, shl, jit},
+/* step_resume */ {sr, sr, sr, sr, sr, sr, sr, sr, sr },
+/* shlib */ {shl, shl, shl, shl, shl, shl, sr, shl, shl},
+/* jit_event */ {jit, jit, jit, jit, jit, jit, sr, jit, jit}
};
#undef kc
#undef sr
#undef ts
#undef shl
+#undef jit
enum bpstat_what_main_action current_action = BPSTAT_WHAT_KEEP_CHECKING;
struct bpstat_what retval;
case bp_shlib_event:
bs_class = shlib_event;
break;
+ case bp_jit_event:
+ bs_class = jit_event;
+ break;
case bp_thread_event:
case bp_overlay_event:
case bp_longjmp_master:
{bp_longjmp_master, "longjmp master"},
{bp_catchpoint, "catchpoint"},
{bp_tracepoint, "tracepoint"},
+ {bp_jit_event, "jit events"},
};
static char bpenables[] = "nynny";
case bp_overlay_event:
case bp_longjmp_master:
case bp_tracepoint:
+ case bp_jit_event:
if (opts.addressprint)
{
annotate_field (4);
case bp_shlib_event:
case bp_thread_event:
case bp_overlay_event:
+ case bp_jit_event:
case bp_longjmp_master:
loc->loc_type = bp_loc_software_breakpoint;
break;
int radix;
};
+/* Create a breakpoint for JIT code registration and unregistration. */
+
+struct breakpoint *
+create_jit_event_breakpoint (struct gdbarch *gdbarch, CORE_ADDR address)
+{
+ struct breakpoint *b;
+
+ b = create_internal_breakpoint (gdbarch, address, bp_jit_event);
+ update_global_location_list_nothrow (1);
+ return b;
+}
void
remove_solib_event_breakpoints (void)
case bp_shlib_event:
case bp_thread_event:
case bp_overlay_event:
+ case bp_jit_event:
case bp_longjmp_master:
break;
}
{
if (b->type != bp_call_dummy
&& b->type != bp_shlib_event
+ && b->type != bp_jit_event
&& b->type != bp_thread_event
&& b->type != bp_overlay_event
&& b->type != bp_longjmp_master
if (b->type != bp_call_dummy
&& b->type != bp_shlib_event
&& b->type != bp_thread_event
+ && b->type != bp_jit_event
&& b->type != bp_overlay_event
&& b->type != bp_longjmp_master
&& b->number >= 0)
case bp_step_resume:
case bp_longjmp:
case bp_longjmp_resume:
+ case bp_jit_event:
break;
}
set_language (save_language);
input_radix = save_input_radix;
+ jit_inferior_created_hook ();
+
create_overlay_event_breakpoint ("_ovly_debug_event");
create_longjmp_master_breakpoint ("longjmp");
create_longjmp_master_breakpoint ("_longjmp");
bp_catchpoint,
bp_tracepoint,
+
+ /* Event for JIT compiled code generation or deletion. */
+ bp_jit_event,
};
/* States of enablement of breakpoint. */
keep checking. */
BPSTAT_WHAT_CHECK_SHLIBS,
+ /* Check for new JITed code. */
+ BPSTAT_WHAT_CHECK_JIT,
+
/* This is just used to keep track of how many enums there are. */
BPSTAT_WHAT_LAST
};
extern void make_breakpoint_permanent (struct breakpoint *);
+extern struct breakpoint *create_jit_event_breakpoint (struct gdbarch *,
+ CORE_ADDR);
+
extern struct breakpoint *create_solib_event_breakpoint (struct gdbarch *,
CORE_ADDR);
+2009-08-20 Reid Kleckner <reid@kleckner.net>
+
+ * gdb.texinfo: Add chapter on JIT interface.
+
2009-08-07 Nick Roberts <nickrob@snap.net.nz>
* gdb.texinfo (Server Prefix): Explain that server prefix suppresses
* Emacs:: Using @value{GDBN} under @sc{gnu} Emacs
* GDB/MI:: @value{GDBN}'s Machine Interface.
* Annotations:: @value{GDBN}'s annotation interface.
+* JIT Interface:: Using the JIT debugging interface.
* GDB Bugs:: Reporting bugs in @value{GDBN}
followed by one or more lowercase hex digits (note that this does not
depend on the language).
+@node JIT Interface
+@chapter JIT Compilation Interface
+@cindex just-in-time compilation
+@cindex JIT compilation interface
+
+This chapter documents @value{GDBN}'s @dfn{just-in-time} (JIT) compilation
+interface. A JIT compiler is a program or library that generates native
+executable code at runtime and executes it, usually in order to achieve good
+performance while maintaining platform independence.
+
+Programs that use JIT compilation are normally difficult to debug because
+portions of their code are generated at runtime, instead of being loaded from
+object files, which is where @value{GDBN} normally finds the program's symbols
+and debug information. In order to debug programs that use JIT compilation,
+@value{GDBN} has an interface that allows the program to register in-memory
+symbol files with @value{GDBN} at runtime.
+
+If you are using @value{GDBN} to debug a program that uses this interface, then
+it should work transparently so long as you have not stripped the binary. If
+you are developing a JIT compiler, then the interface is documented in the rest
+of this chapter. At this time, the only known client of this interface is the
+LLVM JIT.
+
+Broadly speaking, the JIT interface mirrors the dynamic loader interface. The
+JIT compiler communicates with @value{GDBN} by writing data into a global
+variable and calling a fuction at a well-known symbol. When @value{GDBN}
+attaches, it reads a linked list of symbol files from the global variable to
+find existing code, and puts a breakpoint in the function so that it can find
+out about additional code.
+
+@menu
+* Declarations:: Relevant C struct declarations
+* Registering Code:: Steps to register code
+* Unregistering Code:: Steps to unregister code
+@end menu
+
+@node Declarations
+@section JIT Declarations
+
+These are the relevant struct declarations that a C program should include to
+implement the interface:
+
+@smallexample
+typedef enum
+@{
+ JIT_NOACTION = 0,
+ JIT_REGISTER_FN,
+ JIT_UNREGISTER_FN
+@} jit_actions_t;
+
+struct jit_code_entry
+@{
+ struct jit_code_entry *next_entry;
+ struct jit_code_entry *prev_entry;
+ const char *symfile_addr;
+ uint64_t symfile_size;
+@};
+
+struct jit_descriptor
+@{
+ uint32_t version;
+ /* This type should be jit_actions_t, but we use uint32_t
+ to be explicit about the bitwidth. */
+ uint32_t action_flag;
+ struct jit_code_entry *relevant_entry;
+ struct jit_code_entry *first_entry;
+@};
+
+/* GDB puts a breakpoint in this function. */
+void __attribute__((noinline)) __jit_debug_register_code() @{ @};
+
+/* Make sure to specify the version statically, because the
+ debugger may check the version before we can set it. */
+struct jit_descriptor __jit_debug_descriptor = @{ 1, 0, 0, 0 @};
+@end smallexample
+
+If the JIT is multi-threaded, then it is important that the JIT synchronize any
+modifications to this global data properly, which can easily be done by putting
+a global mutex around modifications to these structures.
+
+@node Registering Code
+@section Registering Code
+
+To register code with @value{GDBN}, the JIT should follow this protocol:
+
+@itemize @bullet
+@item
+Generate an object file in memory with symbols and other desired debug
+information. The file must include the virtual addresses of the sections.
+
+@item
+Create a code entry for the file, which gives the start and size of the symbol
+file.
+
+@item
+Add it to the linked list in the JIT descriptor.
+
+@item
+Point the relevant_entry field of the descriptor at the entry.
+
+@item
+Set @code{action_flag} to @code{JIT_REGISTER} and call
+@code{__jit_debug_register_code}.
+@end itemize
+
+When @value{GDBN} is attached and the breakpoint fires, @value{GDBN} uses the
+@code{relevant_entry} pointer so it doesn't have to walk the list looking for
+new code. However, the linked list must still be maintained in order to allow
+@value{GDBN} to attach to a running process and still find the symbol files.
+
+@node Unregistering Code
+@section Unregistering Code
+
+If code is freed, then the JIT should use the following protocol:
+
+@itemize @bullet
+@item
+Remove the code entry corresponding to the code from the linked list.
+
+@item
+Point the @code{relevant_entry} field of the descriptor at the code entry.
+
+@item
+Set @code{action_flag} to @code{JIT_UNREGISTER} and call
+@code{__jit_debug_register_code}.
+@end itemize
+
+If the JIT frees or recompiles code without unregistering it, then @value{GDBN}
+and the JIT will leak the memory used for the associated symbol files.
+
@node GDB Bugs
@chapter Reporting Bugs in @value{GDBN}
@cindex bugs in @value{GDBN}
#include "event-top.h"
#include "record.h"
#include "inline-frame.h"
+#include "jit.h"
/* Prototypes for local functions */
solib_create_inferior_hook ();
#endif
+ jit_inferior_created_hook ();
+
/* Reinsert all breakpoints. (Those which were symbolic have
been reset to the proper address in the new a.out, thanks
to symbol_file_command...) */
}
break;
+ case BPSTAT_WHAT_CHECK_JIT:
+ if (debug_infrun)
+ fprintf_unfiltered (gdb_stdlog, "infrun: BPSTAT_WHAT_CHECK_JIT\n");
+
+ /* Switch terminal for any messages produced by breakpoint_re_set. */
+ target_terminal_ours_for_output ();
+
+ jit_event_handler ();
+
+ target_terminal_inferior ();
+
+ /* We want to step over this breakpoint, then keep going. */
+ ecs->event_thread->stepping_over_breakpoint = 1;
+
+ break;
+
case BPSTAT_WHAT_LAST:
/* Not a real code, but listed here to shut up gcc -Wall. */
--- /dev/null
+/* Handle JIT code generation in the inferior for GDB, the GNU Debugger.
+
+ Copyright (C) 2009
+ Free Software Foundation, Inc.
+
+ This file is part of GDB.
+
+ This program is free software; you can redistribute it and/or modify
+ it under the terms of the GNU General Public License as published by
+ the Free Software Foundation; either version 3 of the License, or
+ (at your option) any later version.
+
+ This program is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ GNU General Public License for more details.
+
+ You should have received a copy of the GNU General Public License
+ along with this program. If not, see <http://www.gnu.org/licenses/>. */
+
+#include "defs.h"
+
+#include "jit.h"
+#include "breakpoint.h"
+#include "gdbcore.h"
+#include "observer.h"
+#include "objfiles.h"
+#include "symfile.h"
+#include "symtab.h"
+#include "target.h"
+#include "gdb_stat.h"
+
+static const struct objfile_data *jit_objfile_data;
+
+static const char *const jit_break_name = "__jit_debug_register_code";
+
+static const char *const jit_descriptor_name = "__jit_debug_descriptor";
+
+/* This is the address of the JIT descriptor in the inferior. */
+
+static CORE_ADDR jit_descriptor_addr = 0;
+
+/* This is a boolean indicating whether we're currently registering code. This
+ is used to avoid re-entering the registration code. We want to check for
+ new JITed every time a new object file is loaded, but we want to avoid
+ checking for new code while we're registering object files for JITed code.
+ Therefore, we flip this variable to 1 before registering new object files,
+ and set it to 0 before returning. */
+
+static int registering_code = 0;
+
+/* Helper cleanup function to clear an integer flag like the one above. */
+
+static void
+clear_int (void *int_addr)
+{
+ *((int *) int_addr) = 0;
+}
+
+struct target_buffer
+{
+ CORE_ADDR base;
+ size_t size;
+};
+
+/* Openning the file is a no-op. */
+
+static void *
+mem_bfd_iovec_open (struct bfd *abfd, void *open_closure)
+{
+ return open_closure;
+}
+
+/* Closing the file is just freeing the base/size pair on our side. */
+
+static int
+mem_bfd_iovec_close (struct bfd *abfd, void *stream)
+{
+ xfree (stream);
+ return 1;
+}
+
+/* For reading the file, we just need to pass through to target_read_memory and
+ fix up the arguments and return values. */
+
+static file_ptr
+mem_bfd_iovec_pread (struct bfd *abfd, void *stream, void *buf,
+ file_ptr nbytes, file_ptr offset)
+{
+ int err;
+ struct target_buffer *buffer = (struct target_buffer *) stream;
+
+ /* If this read will read all of the file, limit it to just the rest. */
+ if (offset + nbytes > buffer->size)
+ nbytes = buffer->size - offset;
+
+ /* If there are no more bytes left, we've reached EOF. */
+ if (nbytes == 0)
+ return 0;
+
+ err = target_read_memory (buffer->base + offset, (gdb_byte *) buf, nbytes);
+ if (err)
+ return -1;
+
+ return nbytes;
+}
+
+/* For statting the file, we only support the st_size attribute. */
+
+static int
+mem_bfd_iovec_stat (struct bfd *abfd, void *stream, struct stat *sb)
+{
+ struct target_buffer *buffer = (struct target_buffer*) stream;
+
+ sb->st_size = buffer->size;
+ return 0;
+}
+
+/* Open a BFD from the target's memory. */
+
+static struct bfd *
+bfd_open_from_target_memory (CORE_ADDR addr, size_t size, char *target)
+{
+ const char *filename = xstrdup ("<in-memory>");
+ struct target_buffer *buffer = xmalloc (sizeof (struct target_buffer));
+
+ buffer->base = addr;
+ buffer->size = size;
+ return bfd_openr_iovec (filename, target,
+ mem_bfd_iovec_open,
+ buffer,
+ mem_bfd_iovec_pread,
+ mem_bfd_iovec_close,
+ mem_bfd_iovec_stat);
+}
+
+/* Helper function for reading the global JIT descriptor from remote memory. */
+
+static void
+jit_read_descriptor (struct jit_descriptor *descriptor)
+{
+ int err;
+ struct type *ptr_type;
+ int ptr_size;
+ int desc_size;
+ gdb_byte *desc_buf;
+ enum bfd_endian byte_order = gdbarch_byte_order (target_gdbarch);
+
+ /* Figure out how big the descriptor is on the remote and how to read it. */
+ ptr_type = builtin_type (target_gdbarch)->builtin_data_ptr;
+ ptr_size = TYPE_LENGTH (ptr_type);
+ desc_size = 8 + 2 * ptr_size; /* Two 32-bit ints and two pointers. */
+ desc_buf = alloca (desc_size);
+
+ /* Read the descriptor. */
+ err = target_read_memory (jit_descriptor_addr, desc_buf, desc_size);
+ if (err)
+ error (_("Unable to read JIT descriptor from remote memory!"));
+
+ /* Fix the endianness to match the host. */
+ descriptor->version = extract_unsigned_integer (&desc_buf[0], 4, byte_order);
+ descriptor->action_flag =
+ extract_unsigned_integer (&desc_buf[4], 4, byte_order);
+ descriptor->relevant_entry = extract_typed_address (&desc_buf[8], ptr_type);
+ descriptor->first_entry =
+ extract_typed_address (&desc_buf[8 + ptr_size], ptr_type);
+}
+
+/* Helper function for reading a JITed code entry from remote memory. */
+
+static void
+jit_read_code_entry (CORE_ADDR code_addr, struct jit_code_entry *code_entry)
+{
+ int err;
+ struct type *ptr_type;
+ int ptr_size;
+ int entry_size;
+ gdb_byte *entry_buf;
+ enum bfd_endian byte_order = gdbarch_byte_order (target_gdbarch);
+
+ /* Figure out how big the entry is on the remote and how to read it. */
+ ptr_type = builtin_type (target_gdbarch)->builtin_data_ptr;
+ ptr_size = TYPE_LENGTH (ptr_type);
+ entry_size = 3 * ptr_size + 8; /* Three pointers and one 64-bit int. */
+ entry_buf = alloca (entry_size);
+
+ /* Read the entry. */
+ err = target_read_memory (code_addr, entry_buf, entry_size);
+ if (err)
+ error (_("Unable to read JIT code entry from remote memory!"));
+
+ /* Fix the endianness to match the host. */
+ ptr_type = builtin_type (target_gdbarch)->builtin_data_ptr;
+ code_entry->next_entry = extract_typed_address (&entry_buf[0], ptr_type);
+ code_entry->prev_entry =
+ extract_typed_address (&entry_buf[ptr_size], ptr_type);
+ code_entry->symfile_addr =
+ extract_typed_address (&entry_buf[2 * ptr_size], ptr_type);
+ code_entry->symfile_size =
+ extract_unsigned_integer (&entry_buf[3 * ptr_size], 8, byte_order);
+}
+
+/* This function registers code associated with a JIT code entry. It uses the
+ pointer and size pair in the entry to read the symbol file from the remote
+ and then calls symbol_file_add_from_local_memory to add it as though it were
+ a symbol file added by the user. */
+
+static void
+jit_register_code (CORE_ADDR entry_addr, struct jit_code_entry *code_entry)
+{
+ bfd *nbfd;
+ struct section_addr_info *sai;
+ struct bfd_section *sec;
+ struct objfile *objfile;
+ struct cleanup *old_cleanups, *my_cleanups;
+ int i;
+ const struct bfd_arch_info *b;
+ CORE_ADDR *entry_addr_ptr;
+
+ nbfd = bfd_open_from_target_memory (code_entry->symfile_addr,
+ code_entry->symfile_size, gnutarget);
+ old_cleanups = make_cleanup_bfd_close (nbfd);
+
+ /* Check the format. NOTE: This initializes important data that GDB uses!
+ We would segfault later without this line. */
+ if (!bfd_check_format (nbfd, bfd_object))
+ {
+ printf_unfiltered (_("\
+JITed symbol file is not an object file, ignoring it.\n"));
+ do_cleanups (old_cleanups);
+ return;
+ }
+
+ /* Check bfd arch. */
+ b = gdbarch_bfd_arch_info (target_gdbarch);
+ if (b->compatible (b, bfd_get_arch_info (nbfd)) != b)
+ warning (_("JITed object file architecture %s is not compatible "
+ "with target architecture %s."), bfd_get_arch_info
+ (nbfd)->printable_name, b->printable_name);
+
+ /* Read the section address information out of the symbol file. Since the
+ file is generated by the JIT at runtime, it should all of the absolute
+ addresses that we care about. */
+ sai = alloc_section_addr_info (bfd_count_sections (nbfd));
+ make_cleanup_free_section_addr_info (sai);
+ i = 0;
+ for (sec = nbfd->sections; sec != NULL; sec = sec->next)
+ if ((bfd_get_section_flags (nbfd, sec) & (SEC_ALLOC|SEC_LOAD)) != 0)
+ {
+ /* We assume that these virtual addresses are absolute, and do not
+ treat them as offsets. */
+ sai->other[i].addr = bfd_get_section_vma (nbfd, sec);
+ sai->other[i].name = (char *) bfd_get_section_name (nbfd, sec);
+ sai->other[i].sectindex = sec->index;
+ ++i;
+ }
+
+ /* Raise this flag while we register code so we won't trigger any
+ re-registration. */
+ registering_code = 1;
+ my_cleanups = make_cleanup (clear_int, ®istering_code);
+
+ /* This call takes ownership of sai. */
+ objfile = symbol_file_add_from_bfd (nbfd, 0, sai, OBJF_SHARED);
+
+ /* Clear the registering_code flag. */
+ do_cleanups (my_cleanups);
+
+ /* Remember a mapping from entry_addr to objfile. */
+ entry_addr_ptr = xmalloc (sizeof (CORE_ADDR));
+ *entry_addr_ptr = entry_addr;
+ set_objfile_data (objfile, jit_objfile_data, entry_addr_ptr);
+
+ discard_cleanups (old_cleanups);
+}
+
+/* This function unregisters JITed code and frees the corresponding objfile. */
+
+static void
+jit_unregister_code (struct objfile *objfile)
+{
+ free_objfile (objfile);
+}
+
+/* Look up the objfile with this code entry address. */
+
+static struct objfile *
+jit_find_objf_with_entry_addr (CORE_ADDR entry_addr)
+{
+ struct objfile *objf;
+ CORE_ADDR *objf_entry_addr;
+
+ ALL_OBJFILES (objf)
+ {
+ objf_entry_addr = (CORE_ADDR *) objfile_data (objf, jit_objfile_data);
+ if (objf_entry_addr != NULL && *objf_entry_addr == entry_addr)
+ return objf;
+ }
+ return NULL;
+}
+
+void
+jit_inferior_created_hook (void)
+{
+ struct minimal_symbol *reg_symbol;
+ struct minimal_symbol *desc_symbol;
+ CORE_ADDR reg_addr;
+ struct jit_descriptor descriptor;
+ struct jit_code_entry cur_entry;
+ CORE_ADDR cur_entry_addr;
+ struct cleanup *old_cleanups;
+
+ /* When we register code, GDB resets its breakpoints in case symbols have
+ changed. That in turn calls this handler, which makes us look for new
+ code again. To avoid being re-entered, we check this flag. */
+ if (registering_code)
+ return;
+
+ /* Lookup the registration symbol. If it is missing, then we assume we are
+ not attached to a JIT. */
+ reg_symbol = lookup_minimal_symbol (jit_break_name, NULL, NULL);
+ if (reg_symbol == NULL)
+ return;
+ reg_addr = SYMBOL_VALUE_ADDRESS (reg_symbol);
+ if (reg_addr == 0)
+ return;
+
+ /* Lookup the descriptor symbol and cache the addr. If it is missing, we
+ assume we are not attached to a JIT and return early. */
+ desc_symbol = lookup_minimal_symbol (jit_descriptor_name, NULL, NULL);
+ if (desc_symbol == NULL)
+ return;
+ jit_descriptor_addr = SYMBOL_VALUE_ADDRESS (desc_symbol);
+ if (jit_descriptor_addr == 0)
+ return;
+
+ /* Read the descriptor so we can check the version number and load any already
+ JITed functions. */
+ jit_read_descriptor (&descriptor);
+
+ /* Check that the version number agrees with that we support. */
+ if (descriptor.version != 1)
+ error (_("Unsupported JIT protocol version in descriptor!"));
+
+ /* Put a breakpoint in the registration symbol. */
+ create_jit_event_breakpoint (target_gdbarch, reg_addr);
+
+ /* If we've attached to a running program, we need to check the descriptor to
+ register any functions that were already generated. */
+ for (cur_entry_addr = descriptor.first_entry;
+ cur_entry_addr != 0;
+ cur_entry_addr = cur_entry.next_entry)
+ {
+ jit_read_code_entry (cur_entry_addr, &cur_entry);
+
+ /* This hook may be called many times during setup, so make sure we don't
+ add the same symbol file twice. */
+ if (jit_find_objf_with_entry_addr (cur_entry_addr) != NULL)
+ continue;
+
+ jit_register_code (cur_entry_addr, &cur_entry);
+ }
+}
+
+/* Wrapper to match the observer function pointer prototype. */
+
+static void
+jit_inferior_created_hook1 (struct target_ops *objfile, int from_tty)
+{
+ jit_inferior_created_hook ();
+}
+
+/* This function cleans up any code entries left over when the inferior exits.
+ We get left over code when the inferior exits without unregistering its code,
+ for example when it crashes. */
+
+static void
+jit_inferior_exit_hook (int pid)
+{
+ struct objfile *objf;
+ struct objfile *temp;
+
+ /* We need to reset the descriptor addr so that next time we load up the
+ inferior we look for it again. */
+ jit_descriptor_addr = 0;
+
+ ALL_OBJFILES_SAFE (objf, temp)
+ if (objfile_data (objf, jit_objfile_data) != NULL)
+ jit_unregister_code (objf);
+}
+
+void
+jit_event_handler (void)
+{
+ struct jit_descriptor descriptor;
+ struct jit_code_entry code_entry;
+ CORE_ADDR entry_addr;
+ struct objfile *objf;
+
+ /* Read the descriptor from remote memory. */
+ jit_read_descriptor (&descriptor);
+ entry_addr = descriptor.relevant_entry;
+
+ /* Do the corresponding action. */
+ switch (descriptor.action_flag)
+ {
+ case JIT_NOACTION:
+ break;
+ case JIT_REGISTER:
+ jit_read_code_entry (entry_addr, &code_entry);
+ jit_register_code (entry_addr, &code_entry);
+ break;
+ case JIT_UNREGISTER:
+ objf = jit_find_objf_with_entry_addr (entry_addr);
+ if (objf == NULL)
+ printf_unfiltered ("Unable to find JITed code entry at address: %p\n",
+ (void *) entry_addr);
+ else
+ jit_unregister_code (objf);
+
+ break;
+ default:
+ error (_("Unknown action_flag value in JIT descriptor!"));
+ break;
+ }
+}
+
+/* Provide a prototype to silence -Wmissing-prototypes. */
+
+extern void _initialize_jit (void);
+
+void
+_initialize_jit (void)
+{
+ observer_attach_inferior_created (jit_inferior_created_hook1);
+ observer_attach_inferior_exit (jit_inferior_exit_hook);
+ jit_objfile_data = register_objfile_data ();
+}
--- /dev/null
+/* JIT declarations for GDB, the GNU Debugger.
+
+ Copyright (C) 2009
+ Free Software Foundation, Inc.
+
+ This file is part of GDB.
+
+ This program is free software; you can redistribute it and/or modify
+ it under the terms of the GNU General Public License as published by
+ the Free Software Foundation; either version 3 of the License, or
+ (at your option) any later version.
+
+ This program is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ GNU General Public License for more details.
+
+ You should have received a copy of the GNU General Public License
+ along with this program. If not, see <http://www.gnu.org/licenses/>. */
+
+#ifndef JIT_H
+#define JIT_H
+
+/* When the JIT breakpoint fires, the inferior wants us to take one of these
+ actions. These values are used by the inferior, so the values of these enums
+ cannot be changed. */
+
+typedef enum
+{
+ JIT_NOACTION = 0,
+ JIT_REGISTER,
+ JIT_UNREGISTER
+} jit_actions_t;
+
+/* This struct describes a single symbol file in a linked list of symbol files
+ describing generated code. As the inferior generates code, it adds these
+ entries to the list, and when we attach to the inferior, we read them all.
+ For the first element prev_entry should be NULL, and for the last element
+ next_entry should be NULL. */
+
+struct jit_code_entry
+{
+ CORE_ADDR next_entry;
+ CORE_ADDR prev_entry;
+ CORE_ADDR symfile_addr;
+ uint64_t symfile_size;
+};
+
+/* This is the global descriptor that the inferior uses to communicate
+ information to the debugger. To alert the debugger to take an action, the
+ inferior sets the action_flag to the appropriate enum value, updates
+ relevant_entry to point to the relevant code entry, and calls the function at
+ the well-known symbol with our breakpoint. We then read this descriptor from
+ another global well-known symbol. */
+
+struct jit_descriptor
+{
+ uint32_t version;
+ /* This should be jit_actions_t, but we want to be specific about the
+ bit-width. */
+ uint32_t action_flag;
+ CORE_ADDR relevant_entry;
+ CORE_ADDR first_entry;
+};
+
+/* Looks for the descriptor and registration symbols and breakpoints the
+ registration function. If it finds both, it registers all the already JITed
+ code. If it has already found the symbols, then it doesn't try again. */
+
+extern void jit_inferior_created_hook (void);
+
+/* This function is called by handle_inferior_event when it decides that the JIT
+ event breakpoint has fired. */
+
+extern void jit_event_handler (void);
+
+#endif /* JIT_H */
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