binutils-gdb/gdb/btrace.c

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/* Branch trace support for GDB, the GNU debugger.
Copyright (C) 2013 Free Software Foundation, Inc.
Contributed by Intel Corp. <markus.t.metzger@intel.com>
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 "btrace.h"
#include "gdbthread.h"
#include "exceptions.h"
#include "inferior.h"
#include "target.h"
#include "record.h"
#include "symtab.h"
#include "disasm.h"
#include "source.h"
#include "filenames.h"
#include "xml-support.h"
/* Print a record debug message. Use do ... while (0) to avoid ambiguities
when used in if statements. */
#define DEBUG(msg, args...) \
do \
{ \
if (record_debug != 0) \
fprintf_unfiltered (gdb_stdlog, \
"[btrace] " msg "\n", ##args); \
} \
while (0)
#define DEBUG_FTRACE(msg, args...) DEBUG ("[ftrace] " msg, ##args)
/* Initialize the instruction iterator. */
static void
btrace_init_insn_iterator (struct btrace_thread_info *btinfo)
{
DEBUG ("init insn iterator");
btinfo->insn_iterator.begin = 1;
btinfo->insn_iterator.end = 0;
}
/* Initialize the function iterator. */
static void
btrace_init_func_iterator (struct btrace_thread_info *btinfo)
{
DEBUG ("init func iterator");
btinfo->func_iterator.begin = 1;
btinfo->func_iterator.end = 0;
}
/* Compute the instruction trace from the block trace. */
static VEC (btrace_inst_s) *
compute_itrace (VEC (btrace_block_s) *btrace)
{
VEC (btrace_inst_s) *itrace;
struct gdbarch *gdbarch;
unsigned int b;
DEBUG ("compute itrace");
itrace = NULL;
gdbarch = target_gdbarch ();
b = VEC_length (btrace_block_s, btrace);
while (b-- != 0)
{
btrace_block_s *block;
CORE_ADDR pc;
block = VEC_index (btrace_block_s, btrace, b);
pc = block->begin;
/* Add instructions for this block. */
for (;;)
{
btrace_inst_s *inst;
int size;
/* We should hit the end of the block. Warn if we went too far. */
if (block->end < pc)
{
warning (_("Recorded trace may be corrupted."));
break;
}
inst = VEC_safe_push (btrace_inst_s, itrace, NULL);
inst->pc = pc;
/* We're done once we pushed the instruction at the end. */
if (block->end == pc)
break;
size = gdb_insn_length (gdbarch, pc);
/* Make sure we terminate if we fail to compute the size. */
if (size <= 0)
{
warning (_("Recorded trace may be incomplete."));
break;
}
pc += size;
}
}
return itrace;
}
/* Return the function name of a recorded function segment for printing.
This function never returns NULL. */
static const char *
ftrace_print_function_name (struct btrace_func *bfun)
{
struct minimal_symbol *msym;
struct symbol *sym;
msym = bfun->msym;
sym = bfun->sym;
if (sym != NULL)
return SYMBOL_PRINT_NAME (sym);
if (msym != NULL)
return SYMBOL_PRINT_NAME (msym);
return "<unknown>";
}
/* Return the file name of a recorded function segment for printing.
This function never returns NULL. */
static const char *
ftrace_print_filename (struct btrace_func *bfun)
{
struct symbol *sym;
const char *filename;
sym = bfun->sym;
if (sym != NULL)
filename = symtab_to_filename_for_display (sym->symtab);
else
filename = "<unknown>";
return filename;
}
/* Print an ftrace debug status message. */
static void
ftrace_debug (struct btrace_func *bfun, const char *prefix)
{
DEBUG_FTRACE ("%s: fun = %s, file = %s, lines = [%d; %d], insn = [%u; %u]",
prefix, ftrace_print_function_name (bfun),
ftrace_print_filename (bfun), bfun->lbegin, bfun->lend,
bfun->ibegin, bfun->iend);
}
/* Initialize a recorded function segment. */
static void
ftrace_init_func (struct btrace_func *bfun, struct minimal_symbol *mfun,
struct symbol *fun, unsigned int idx)
{
bfun->msym = mfun;
bfun->sym = fun;
bfun->lbegin = INT_MAX;
bfun->lend = 0;
bfun->ibegin = idx;
bfun->iend = idx;
}
/* Check whether the function has changed. */
static int
ftrace_function_switched (struct btrace_func *bfun,
struct minimal_symbol *mfun, struct symbol *fun)
{
struct minimal_symbol *msym;
struct symbol *sym;
/* The function changed if we did not have one before. */
if (bfun == NULL)
return 1;
msym = bfun->msym;
sym = bfun->sym;
/* If the minimal symbol changed, we certainly switched functions. */
if (mfun != NULL && msym != NULL
&& strcmp (SYMBOL_LINKAGE_NAME (mfun), SYMBOL_LINKAGE_NAME (msym)) != 0)
return 1;
/* If the symbol changed, we certainly switched functions. */
if (fun != NULL && sym != NULL)
{
const char *bfname, *fname;
/* Check the function name. */
if (strcmp (SYMBOL_LINKAGE_NAME (fun), SYMBOL_LINKAGE_NAME (sym)) != 0)
return 1;
/* Check the location of those functions, as well. */
bfname = symtab_to_fullname (sym->symtab);
fname = symtab_to_fullname (fun->symtab);
if (filename_cmp (fname, bfname) != 0)
return 1;
}
return 0;
}
/* Check if we should skip this file when generating the function call
history. We would want to do that if, say, a macro that is defined
in another file is expanded in this function. */
static int
ftrace_skip_file (struct btrace_func *bfun, const char *filename)
{
struct symbol *sym;
const char *bfile;
sym = bfun->sym;
if (sym != NULL)
bfile = symtab_to_fullname (sym->symtab);
else
bfile = "";
if (filename == NULL)
filename = "";
return (filename_cmp (bfile, filename) != 0);
}
/* Compute the function trace from the instruction trace. */
static VEC (btrace_func_s) *
compute_ftrace (VEC (btrace_inst_s) *itrace)
{
VEC (btrace_func_s) *ftrace;
struct btrace_inst *binst;
struct btrace_func *bfun;
unsigned int idx;
DEBUG ("compute ftrace");
ftrace = NULL;
bfun = NULL;
for (idx = 0; VEC_iterate (btrace_inst_s, itrace, idx, binst); ++idx)
{
struct symtab_and_line sal;
struct bound_minimal_symbol mfun;
struct symbol *fun;
const char *filename;
CORE_ADDR pc;
pc = binst->pc;
/* Try to determine the function we're in. We use both types of symbols
to avoid surprises when we sometimes get a full symbol and sometimes
only a minimal symbol. */
fun = find_pc_function (pc);
mfun = lookup_minimal_symbol_by_pc (pc);
if (fun == NULL && mfun.minsym == NULL)
{
DEBUG_FTRACE ("no symbol at %u, pc=%s", idx,
core_addr_to_string_nz (pc));
continue;
}
/* If we're switching functions, we start over. */
if (ftrace_function_switched (bfun, mfun.minsym, fun))
{
bfun = VEC_safe_push (btrace_func_s, ftrace, NULL);
ftrace_init_func (bfun, mfun.minsym, fun, idx);
ftrace_debug (bfun, "init");
}
/* Update the instruction range. */
bfun->iend = idx;
ftrace_debug (bfun, "update insns");
/* Let's see if we have source correlation, as well. */
sal = find_pc_line (pc, 0);
if (sal.symtab == NULL || sal.line == 0)
{
DEBUG_FTRACE ("no lines at %u, pc=%s", idx,
core_addr_to_string_nz (pc));
continue;
}
/* Check if we switched files. This could happen if, say, a macro that
is defined in another file is expanded here. */
filename = symtab_to_fullname (sal.symtab);
if (ftrace_skip_file (bfun, filename))
{
DEBUG_FTRACE ("ignoring file at %u, pc=%s, file=%s", idx,
core_addr_to_string_nz (pc), filename);
continue;
}
/* Update the line range. */
bfun->lbegin = min (bfun->lbegin, sal.line);
bfun->lend = max (bfun->lend, sal.line);
ftrace_debug (bfun, "update lines");
}
return ftrace;
}
/* See btrace.h. */
void
btrace_enable (struct thread_info *tp)
{
if (tp->btrace.target != NULL)
return;
if (!target_supports_btrace ())
error (_("Target does not support branch tracing."));
DEBUG ("enable thread %d (%s)", tp->num, target_pid_to_str (tp->ptid));
tp->btrace.target = target_enable_btrace (tp->ptid);
}
/* See btrace.h. */
void
btrace_disable (struct thread_info *tp)
{
struct btrace_thread_info *btp = &tp->btrace;
int errcode = 0;
if (btp->target == NULL)
return;
DEBUG ("disable thread %d (%s)", tp->num, target_pid_to_str (tp->ptid));
target_disable_btrace (btp->target);
btp->target = NULL;
btrace_clear (tp);
}
/* See btrace.h. */
void
btrace_teardown (struct thread_info *tp)
{
struct btrace_thread_info *btp = &tp->btrace;
int errcode = 0;
if (btp->target == NULL)
return;
DEBUG ("teardown thread %d (%s)", tp->num, target_pid_to_str (tp->ptid));
target_teardown_btrace (btp->target);
btp->target = NULL;
btrace_clear (tp);
}
/* See btrace.h. */
void
btrace_fetch (struct thread_info *tp)
{
struct btrace_thread_info *btinfo;
VEC (btrace_block_s) *btrace;
DEBUG ("fetch thread %d (%s)", tp->num, target_pid_to_str (tp->ptid));
btinfo = &tp->btrace;
if (btinfo->target == NULL)
return;
btrace = target_read_btrace (btinfo->target, btrace_read_new);
if (VEC_empty (btrace_block_s, btrace))
return;
btrace_clear (tp);
btinfo->btrace = btrace;
btinfo->itrace = compute_itrace (btinfo->btrace);
btinfo->ftrace = compute_ftrace (btinfo->itrace);
/* Initialize branch trace iterators. */
btrace_init_insn_iterator (btinfo);
btrace_init_func_iterator (btinfo);
}
/* See btrace.h. */
void
btrace_clear (struct thread_info *tp)
{
struct btrace_thread_info *btinfo;
DEBUG ("clear thread %d (%s)", tp->num, target_pid_to_str (tp->ptid));
btinfo = &tp->btrace;
VEC_free (btrace_block_s, btinfo->btrace);
VEC_free (btrace_inst_s, btinfo->itrace);
VEC_free (btrace_func_s, btinfo->ftrace);
btinfo->btrace = NULL;
btinfo->itrace = NULL;
btinfo->ftrace = NULL;
}
/* See btrace.h. */
void
btrace_free_objfile (struct objfile *objfile)
{
struct thread_info *tp;
DEBUG ("free objfile");
ALL_THREADS (tp)
btrace_clear (tp);
}
#if defined (HAVE_LIBEXPAT)
/* Check the btrace document version. */
static void
check_xml_btrace_version (struct gdb_xml_parser *parser,
const struct gdb_xml_element *element,
void *user_data, VEC (gdb_xml_value_s) *attributes)
{
const char *version = xml_find_attribute (attributes, "version")->value;
if (strcmp (version, "1.0") != 0)
gdb_xml_error (parser, _("Unsupported btrace version: \"%s\""), version);
}
/* Parse a btrace "block" xml record. */
static void
parse_xml_btrace_block (struct gdb_xml_parser *parser,
const struct gdb_xml_element *element,
void *user_data, VEC (gdb_xml_value_s) *attributes)
{
VEC (btrace_block_s) **btrace;
struct btrace_block *block;
ULONGEST *begin, *end;
btrace = user_data;
block = VEC_safe_push (btrace_block_s, *btrace, NULL);
begin = xml_find_attribute (attributes, "begin")->value;
end = xml_find_attribute (attributes, "end")->value;
block->begin = *begin;
block->end = *end;
}
static const struct gdb_xml_attribute block_attributes[] = {
{ "begin", GDB_XML_AF_NONE, gdb_xml_parse_attr_ulongest, NULL },
{ "end", GDB_XML_AF_NONE, gdb_xml_parse_attr_ulongest, NULL },
{ NULL, GDB_XML_AF_NONE, NULL, NULL }
};
static const struct gdb_xml_attribute btrace_attributes[] = {
{ "version", GDB_XML_AF_NONE, NULL, NULL },
{ NULL, GDB_XML_AF_NONE, NULL, NULL }
};
static const struct gdb_xml_element btrace_children[] = {
{ "block", block_attributes, NULL,
GDB_XML_EF_REPEATABLE | GDB_XML_EF_OPTIONAL, parse_xml_btrace_block, NULL },
{ NULL, NULL, NULL, GDB_XML_EF_NONE, NULL, NULL }
};
static const struct gdb_xml_element btrace_elements[] = {
{ "btrace", btrace_attributes, btrace_children, GDB_XML_EF_NONE,
check_xml_btrace_version, NULL },
{ NULL, NULL, NULL, GDB_XML_EF_NONE, NULL, NULL }
};
#endif /* defined (HAVE_LIBEXPAT) */
/* See btrace.h. */
VEC (btrace_block_s) *
parse_xml_btrace (const char *buffer)
{
VEC (btrace_block_s) *btrace = NULL;
struct cleanup *cleanup;
int errcode;
#if defined (HAVE_LIBEXPAT)
cleanup = make_cleanup (VEC_cleanup (btrace_block_s), &btrace);
errcode = gdb_xml_parse_quick (_("btrace"), "btrace.dtd", btrace_elements,
buffer, &btrace);
if (errcode != 0)
{
do_cleanups (cleanup);
return NULL;
}
/* Keep parse results. */
discard_cleanups (cleanup);
#else /* !defined (HAVE_LIBEXPAT) */
error (_("Cannot process branch trace. XML parsing is not supported."));
#endif /* !defined (HAVE_LIBEXPAT) */
return btrace;
}