Add a target for branch trace recording.

The target implements the new record sub-commands
"record instruction-history" and
"record function-call-history".

The target does not support reverse execution or navigation in the
recorded execution log.

gdb/
	* Makefile.in (SFILES): Add record-btrace.c
	(COMMON_OBS): Add record-btrace.o
	* record-btrace.c: New.
	* objfiles.c: Include btrace.h.
	(free_objfile): call btrace_free_objfile.

4 files changed, 704 insertions, 2 deletions

diff --git a/gdb/ChangeLog b/gdb/ChangeLog
index 7383927..f1f4611 100644
--- a/gdb/ChangeLog
+++ b/gdb/ChangeLog
@@ -1,5 +1,13 @@
 2013-03-11  Markus Metzger  <markus.t.metzger@intel.com>
 
+	* Makefile.in (SFILES): Add record-btrace.c
+	(COMMON_OBS): Add record-btrace.o
+	* record-btrace.c: New.
+	* objfiles.c: Include btrace.h.
+	(free_objfile): call btrace_free_objfile.
+
+2013-03-11  Markus Metzger  <markus.t.metzger@intel.com>
+
 	* target.c (target_call_history, target_call_history_from,
 	target_call_history_range): New.
 	* target.h (target_ops) <to_call_history, to_call_history_from,
diff --git a/gdb/Makefile.in b/gdb/Makefile.in
index a36d576..5366d9e 100644
--- a/gdb/Makefile.in
+++ b/gdb/Makefile.in
@@ -760,7 +760,7 @@ SFILES = ada-exp.y ada-lang.c ada-typeprint.c ada-valprint.c ada-tasks.c \
 	regset.c sol-thread.c windows-termcap.c \
 	common/gdb_vecs.c common/common-utils.c common/xml-utils.c \
 	common/ptid.c common/buffer.c gdb-dlfcn.c common/agent.c \
-	common/format.c btrace.c
+	common/format.c btrace.c record-btrace.c
 
 LINTFILES = $(SFILES) $(YYFILES) $(CONFIG_SRCS) init.c
 
@@ -930,7 +930,7 @@ COMMON_OBS = $(DEPFILES) $(CONFIG_OBS) $(YYOBJ) \
 	inferior.o osdata.o gdb_usleep.o record.o record-full.o gcore.o \
 	gdb_vecs.o jit.o progspace.o skip.o probe.o \
 	common-utils.o buffer.o ptid.o gdb-dlfcn.o common-agent.o \
-	format.o registry.o btrace.o
+	format.o registry.o btrace.o record-btrace.o
 
 TSOBS = inflow.o
 
diff --git a/gdb/objfiles.c b/gdb/objfiles.c
index 8c17c14..3017fdf 100644
--- a/gdb/objfiles.c
+++ b/gdb/objfiles.c
@@ -53,6 +53,7 @@
 #include "psymtab.h"
 #include "solist.h"
 #include "gdb_bfd.h"
+#include "btrace.h"
 
 /* Keep a registry of per-objfile data-pointers required by other GDB
    modules.  */
@@ -567,6 +568,7 @@ free_objfile (struct objfile *objfile)
   forget_cached_source_info_for_objfile (objfile);
 
   breakpoint_free_objfile (objfile);
+  btrace_free_objfile (objfile);
 
   /* First do any symbol file specific actions required when we are
      finished with a particular symbol file.  Note that if the objfile
diff --git a/gdb/record-btrace.c b/gdb/record-btrace.c
new file mode 100644
index 0000000..bbb0bd5
--- /dev/null
+++ b/gdb/record-btrace.c
@@ -0,0 +1,692 @@
+/* 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 "defs.h"
+#include "record.h"
+#include "gdbthread.h"
+#include "target.h"
+#include "gdbcmd.h"
+#include "disasm.h"
+#include "observer.h"
+#include "exceptions.h"
+#include "cli/cli-utils.h"
+#include "source.h"
+#include "ui-out.h"
+#include "symtab.h"
+#include "filenames.h"
+
+/* The target_ops of record-btrace.  */
+static struct target_ops record_btrace_ops;
+
+/* A new thread observer enabling branch tracing for the new thread.  */
+static struct observer *record_btrace_thread_observer;
+
+/* Print a record-btrace 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,					\
+			    "[record-btrace] " msg "\n", ##args);	\
+    }									\
+  while (0)
+
+
+/* Update the branch trace for the current thread and return a pointer to its
+   branch trace information struct.
+
+   Throws an error if there is no thread or no trace.  This function never
+   returns NULL.  */
+
+static struct btrace_thread_info *
+require_btrace (void)
+{
+  struct thread_info *tp;
+  struct btrace_thread_info *btinfo;
+
+  DEBUG ("require");
+
+  tp = find_thread_ptid (inferior_ptid);
+  if (tp == NULL)
+    error (_("No thread."));
+
+  btrace_fetch (tp);
+
+  btinfo = &tp->btrace;
+
+  if (VEC_empty (btrace_inst_s, btinfo->itrace))
+    error (_("No trace."));
+
+  return btinfo;
+}
+
+/* Enable branch tracing for one thread.  Warn on errors.  */
+
+static void
+record_btrace_enable_warn (struct thread_info *tp)
+{
+  volatile struct gdb_exception error;
+
+  TRY_CATCH (error, RETURN_MASK_ERROR)
+    btrace_enable (tp);
+
+  if (error.message != NULL)
+    warning ("%s", error.message);
+}
+
+/* Callback function to disable branch tracing for one thread.  */
+
+static void
+record_btrace_disable_callback (void *arg)
+{
+  struct thread_info *tp;
+
+  tp = arg;
+
+  btrace_disable (tp);
+}
+
+/* Enable automatic tracing of new threads.  */
+
+static void
+record_btrace_auto_enable (void)
+{
+  DEBUG ("attach thread observer");
+
+  record_btrace_thread_observer
+    = observer_attach_new_thread (record_btrace_enable_warn);
+}
+
+/* Disable automatic tracing of new threads.  */
+
+static void
+record_btrace_auto_disable (void)
+{
+  /* The observer may have been detached, already.  */
+  if (record_btrace_thread_observer == NULL)
+    return;
+
+  DEBUG ("detach thread observer");
+
+  observer_detach_new_thread (record_btrace_thread_observer);
+  record_btrace_thread_observer = NULL;
+}
+
+/* The to_open method of target record-btrace.  */
+
+static void
+record_btrace_open (char *args, int from_tty)
+{
+  struct cleanup *disable_chain;
+  struct thread_info *tp;
+
+  DEBUG ("open");
+
+  if (RECORD_IS_USED)
+    error (_("The process is already being recorded."));
+
+  if (!target_has_execution)
+    error (_("The program is not being run."));
+
+  if (!target_supports_btrace ())
+    error (_("Target does not support branch tracing."));
+
+  gdb_assert (record_btrace_thread_observer == NULL);
+
+  disable_chain = make_cleanup (null_cleanup, NULL);
+  ALL_THREADS (tp)
+    if (args == NULL || *args == 0 || number_is_in_list (args, tp->num))
+      {
+	btrace_enable (tp);
+
+	make_cleanup (record_btrace_disable_callback, tp);
+      }
+
+  record_btrace_auto_enable ();
+
+  push_target (&record_btrace_ops);
+
+  observer_notify_record_changed (current_inferior (),  1);
+
+  discard_cleanups (disable_chain);
+}
+
+/* The to_stop_recording method of target record-btrace.  */
+
+static void
+record_btrace_stop_recording (void)
+{
+  struct thread_info *tp;
+
+  DEBUG ("stop recording");
+
+  record_btrace_auto_disable ();
+
+  ALL_THREADS (tp)
+    if (tp->btrace.target != NULL)
+      btrace_disable (tp);
+}
+
+/* The to_close method of target record-btrace.  */
+
+static void
+record_btrace_close (int quitting)
+{
+  /* We already stopped recording.  */
+}
+
+/* The to_info_record method of target record-btrace.  */
+
+static void
+record_btrace_info (void)
+{
+  struct btrace_thread_info *btinfo;
+  struct thread_info *tp;
+  unsigned int insts, funcs;
+
+  DEBUG ("info");
+
+  tp = find_thread_ptid (inferior_ptid);
+  if (tp == NULL)
+    error (_("No thread."));
+
+  btrace_fetch (tp);
+
+  btinfo = &tp->btrace;
+  insts = VEC_length (btrace_inst_s, btinfo->itrace);
+  funcs = VEC_length (btrace_func_s, btinfo->ftrace);
+
+  printf_unfiltered (_("Recorded %u instructions in %u functions for thread "
+		       "%d (%s).\n"), insts, funcs, tp->num,
+		     target_pid_to_str (tp->ptid));
+}
+
+/* Print an unsigned int.  */
+
+static void
+ui_out_field_uint (struct ui_out *uiout, const char *fld, unsigned int val)
+{
+  ui_out_field_fmt (uiout, fld, "%u", val);
+}
+
+/* Disassemble a section of the recorded instruction trace.  */
+
+static void
+btrace_insn_history (struct btrace_thread_info *btinfo, struct ui_out *uiout,
+		     unsigned int begin, unsigned int end, int flags)
+{
+  struct gdbarch *gdbarch;
+  struct btrace_inst *inst;
+  unsigned int idx;
+
+  DEBUG ("itrace (0x%x): [%u; %u[", flags, begin, end);
+
+  gdbarch = target_gdbarch ();
+
+  for (idx = begin; VEC_iterate (btrace_inst_s, btinfo->itrace, idx, inst)
+	 && idx < end; ++idx)
+    {
+      /* Print the instruction index.  */
+      ui_out_field_uint (uiout, "index", idx);
+      ui_out_text (uiout, "\t");
+
+      /* Disassembly with '/m' flag may not produce the expected result.
+	 See PR gdb/11833.  */
+      gdb_disassembly (gdbarch, uiout, NULL, flags, 1, inst->pc, inst->pc + 1);
+    }
+}
+
+/* The to_insn_history method of target record-btrace.  */
+
+static void
+record_btrace_insn_history (int size, int flags)
+{
+  struct btrace_thread_info *btinfo;
+  struct cleanup *uiout_cleanup;
+  struct ui_out *uiout;
+  unsigned int context, last, begin, end;
+
+  uiout = current_uiout;
+  uiout_cleanup = make_cleanup_ui_out_tuple_begin_end (uiout,
+						       "insn history");
+  btinfo = require_btrace ();
+  last = VEC_length (btrace_inst_s, btinfo->itrace);
+
+  context = abs (size);
+  begin = btinfo->insn_iterator.begin;
+  end = btinfo->insn_iterator.end;
+
+  DEBUG ("insn-history (0x%x): %d, prev: [%u; %u[", flags, size, begin, end);
+
+  if (context == 0)
+    error (_("Bad record instruction-history-size."));
+
+  /* We start at the end.  */
+  if (end < begin)
+    {
+      /* Truncate the context, if necessary.  */
+      context = min (context, last);
+
+      end = last;
+      begin = end - context;
+    }
+  else if (size < 0)
+    {
+      if (begin == 0)
+	{
+	  printf_unfiltered (_("At the start of the branch trace record.\n"));
+
+	  btinfo->insn_iterator.end = 0;
+	  return;
+	}
+
+      /* Truncate the context, if necessary.  */
+      context = min (context, begin);
+
+      end = begin;
+      begin -= context;
+    }
+  else
+    {
+      if (end == last)
+	{
+	  printf_unfiltered (_("At the end of the branch trace record.\n"));
+
+	  btinfo->insn_iterator.begin = last;
+	  return;
+	}
+
+      /* Truncate the context, if necessary.  */
+      context = min (context, last - end);
+
+      begin = end;
+      end += context;
+    }
+
+  btrace_insn_history (btinfo, uiout, begin, end, flags);
+
+  btinfo->insn_iterator.begin = begin;
+  btinfo->insn_iterator.end = end;
+
+  do_cleanups (uiout_cleanup);
+}
+
+/* The to_insn_history_range method of target record-btrace.  */
+
+static void
+record_btrace_insn_history_range (ULONGEST from, ULONGEST to, int flags)
+{
+  struct btrace_thread_info *btinfo;
+  struct cleanup *uiout_cleanup;
+  struct ui_out *uiout;
+  unsigned int last, begin, end;
+
+  uiout = current_uiout;
+  uiout_cleanup = make_cleanup_ui_out_tuple_begin_end (uiout,
+						       "insn history");
+  btinfo = require_btrace ();
+  last = VEC_length (btrace_inst_s, btinfo->itrace);
+
+  begin = (unsigned int) from;
+  end = (unsigned int) to;
+
+  DEBUG ("insn-history (0x%x): [%u; %u[", flags, begin, end);
+
+  /* Check for wrap-arounds.  */
+  if (begin != from || end != to)
+    error (_("Bad range."));
+
+  if (end <= begin)
+    error (_("Bad range."));
+
+  if (last <= begin)
+    error (_("Range out of bounds."));
+
+  /* Truncate the range, if necessary.  */
+  if (last < end)
+    end = last;
+
+  btrace_insn_history (btinfo, uiout, begin, end, flags);
+
+  btinfo->insn_iterator.begin = begin;
+  btinfo->insn_iterator.end = end;
+
+  do_cleanups (uiout_cleanup);
+}
+
+/* The to_insn_history_from method of target record-btrace.  */
+
+static void
+record_btrace_insn_history_from (ULONGEST from, int size, int flags)
+{
+  ULONGEST begin, end, context;
+
+  context = abs (size);
+
+  if (size < 0)
+    {
+      end = from;
+
+      if (from < context)
+	begin = 0;
+      else
+	begin = from - context;
+    }
+  else
+    {
+      begin = from;
+      end = from + context;
+
+      /* Check for wrap-around.  */
+      if (end < begin)
+	end = ULONGEST_MAX;
+    }
+
+  record_btrace_insn_history_range (begin, end, flags);
+}
+
+/* Print the instruction number range for a function call history line.  */
+
+static void
+btrace_func_history_insn_range (struct ui_out *uiout, struct btrace_func *bfun)
+{
+  ui_out_field_uint (uiout, "insn begin", bfun->ibegin);
+
+  if (bfun->ibegin == bfun->iend)
+    return;
+
+  ui_out_text (uiout, "-");
+  ui_out_field_uint (uiout, "insn end", bfun->iend);
+}
+
+/* Print the source line information for a function call history line.  */
+
+static void
+btrace_func_history_src_line (struct ui_out *uiout, struct btrace_func *bfun)
+{
+  struct symbol *sym;
+
+  sym = bfun->sym;
+  if (sym == NULL)
+    return;
+
+  ui_out_field_string (uiout, "file",
+		       symtab_to_filename_for_display (sym->symtab));
+
+  if (bfun->lend == 0)
+    return;
+
+  ui_out_text (uiout, ":");
+  ui_out_field_int (uiout, "min line", bfun->lbegin);
+
+  if (bfun->lend == bfun->lbegin)
+    return;
+
+  ui_out_text (uiout, "-");
+  ui_out_field_int (uiout, "max line", bfun->lend);
+}
+
+/* Disassemble a section of the recorded function trace.  */
+
+static void
+btrace_func_history (struct btrace_thread_info *btinfo, struct ui_out *uiout,
+		     unsigned int begin, unsigned int end,
+		     enum record_print_flag flags)
+{
+  struct btrace_func *bfun;
+  unsigned int idx;
+
+  DEBUG ("ftrace (0x%x): [%u; %u[", flags, begin, end);
+
+  for (idx = begin; VEC_iterate (btrace_func_s, btinfo->ftrace, idx, bfun)
+	 && idx < end; ++idx)
+    {
+      /* Print the function index.  */
+      ui_out_field_uint (uiout, "index", idx);
+      ui_out_text (uiout, "\t");
+
+      if ((flags & record_print_insn_range) != 0)
+	{
+	  btrace_func_history_insn_range (uiout, bfun);
+	  ui_out_text (uiout, "\t");
+	}
+
+      if ((flags & record_print_src_line) != 0)
+	{
+	  btrace_func_history_src_line (uiout, bfun);
+	  ui_out_text (uiout, "\t");
+	}
+
+      if (bfun->sym != NULL)
+	ui_out_field_string (uiout, "function", SYMBOL_PRINT_NAME (bfun->sym));
+      else if (bfun->msym != NULL)
+	ui_out_field_string (uiout, "function", SYMBOL_PRINT_NAME (bfun->msym));
+      ui_out_text (uiout, "\n");
+    }
+}
+
+/* The to_call_history method of target record-btrace.  */
+
+static void
+record_btrace_call_history (int size, int flags)
+{
+  struct btrace_thread_info *btinfo;
+  struct cleanup *uiout_cleanup;
+  struct ui_out *uiout;
+  unsigned int context, last, begin, end;
+
+  uiout = current_uiout;
+  uiout_cleanup = make_cleanup_ui_out_tuple_begin_end (uiout,
+						       "insn history");
+  btinfo = require_btrace ();
+  last = VEC_length (btrace_func_s, btinfo->ftrace);
+
+  context = abs (size);
+  begin = btinfo->func_iterator.begin;
+  end = btinfo->func_iterator.end;
+
+  DEBUG ("func-history (0x%x): %d, prev: [%u; %u[", flags, size, begin, end);
+
+  if (context == 0)
+    error (_("Bad record function-call-history-size."));
+
+  /* We start at the end.  */
+  if (end < begin)
+    {
+      /* Truncate the context, if necessary.  */
+      context = min (context, last);
+
+      end = last;
+      begin = end - context;
+    }
+  else if (size < 0)
+    {
+      if (begin == 0)
+	{
+	  printf_unfiltered (_("At the start of the branch trace record.\n"));
+
+	  btinfo->func_iterator.end = 0;
+	  return;
+	}
+
+      /* Truncate the context, if necessary.  */
+      context = min (context, begin);
+
+      end = begin;
+      begin -= context;
+    }
+  else
+    {
+      if (end == last)
+	{
+	  printf_unfiltered (_("At the end of the branch trace record.\n"));
+
+	  btinfo->func_iterator.begin = last;
+	  return;
+	}
+
+      /* Truncate the context, if necessary.  */
+      context = min (context, last - end);
+
+      begin = end;
+      end += context;
+    }
+
+  btrace_func_history (btinfo, uiout, begin, end, flags);
+
+  btinfo->func_iterator.begin = begin;
+  btinfo->func_iterator.end = end;
+
+  do_cleanups (uiout_cleanup);
+}
+
+/* The to_call_history_range method of target record-btrace.  */
+
+static void
+record_btrace_call_history_range (ULONGEST from, ULONGEST to, int flags)
+{
+  struct btrace_thread_info *btinfo;
+  struct cleanup *uiout_cleanup;
+  struct ui_out *uiout;
+  unsigned int last, begin, end;
+
+  uiout = current_uiout;
+  uiout_cleanup = make_cleanup_ui_out_tuple_begin_end (uiout,
+						       "func history");
+  btinfo = require_btrace ();
+  last = VEC_length (btrace_func_s, btinfo->ftrace);
+
+  begin = (unsigned int) from;
+  end = (unsigned int) to;
+
+  DEBUG ("func-history (0x%x): [%u; %u[", flags, begin, end);
+
+  /* Check for wrap-arounds.  */
+  if (begin != from || end != to)
+    error (_("Bad range."));
+
+  if (end <= begin)
+    error (_("Bad range."));
+
+  if (last <= begin)
+    error (_("Range out of bounds."));
+
+  /* Truncate the range, if necessary.  */
+  if (last < end)
+    end = last;
+
+  btrace_func_history (btinfo, uiout, begin, end, flags);
+
+  btinfo->func_iterator.begin = begin;
+  btinfo->func_iterator.end = end;
+
+  do_cleanups (uiout_cleanup);
+}
+
+/* The to_call_history_from method of target record-btrace.  */
+
+static void
+record_btrace_call_history_from (ULONGEST from, int size, int flags)
+{
+  ULONGEST begin, end, context;
+
+  context = abs (size);
+
+  if (size < 0)
+    {
+      end = from;
+
+      if (from < context)
+	begin = 0;
+      else
+	begin = from - context;
+    }
+  else
+    {
+      begin = from;
+      end = from + context;
+
+      /* Check for wrap-around.  */
+      if (end < begin)
+	end = ULONGEST_MAX;
+    }
+
+  record_btrace_call_history_range (begin, end, flags);
+}
+
+/* Initialize the record-btrace target ops.  */
+
+static void
+init_record_btrace_ops (void)
+{
+  struct target_ops *ops;
+
+  ops = &record_btrace_ops;
+  ops->to_shortname = "record-btrace";
+  ops->to_longname = "Branch tracing target";
+  ops->to_doc = "Collect control-flow trace and provide the execution history.";
+  ops->to_open = record_btrace_open;
+  ops->to_close = record_btrace_close;
+  ops->to_detach = record_detach;
+  ops->to_disconnect = record_disconnect;
+  ops->to_mourn_inferior = record_mourn_inferior;
+  ops->to_kill = record_kill;
+  ops->to_create_inferior = find_default_create_inferior;
+  ops->to_stop_recording = record_btrace_stop_recording;
+  ops->to_info_record = record_btrace_info;
+  ops->to_insn_history = record_btrace_insn_history;
+  ops->to_insn_history_from = record_btrace_insn_history_from;
+  ops->to_insn_history_range = record_btrace_insn_history_range;
+  ops->to_call_history = record_btrace_call_history;
+  ops->to_call_history_from = record_btrace_call_history_from;
+  ops->to_call_history_range = record_btrace_call_history_range;
+  ops->to_stratum = record_stratum;
+  ops->to_magic = OPS_MAGIC;
+}
+
+/* Alias for "target record".  */
+
+static void
+cmd_record_btrace_start (char *args, int from_tty)
+{
+  if (args != NULL && *args != 0)
+    error (_("Invalid argument."));
+
+  execute_command ("target record-btrace", from_tty);
+}
+
+void _initialize_record_btrace (void);
+
+/* Initialize btrace commands.  */
+
+void
+_initialize_record_btrace (void)
+{
+  add_cmd ("btrace", class_obscure, cmd_record_btrace_start,
+	   _("Start branch trace recording."),
+	   &record_cmdlist);
+  add_alias_cmd ("b", "btrace", class_obscure, 1, &record_cmdlist);
+
+  init_record_btrace_ops ();
+  add_target (&record_btrace_ops);
+}