[PATCH 1/3] record, btrace: add record-btrace target

[markus dot t dot metzger at intel dot com]

From: Markus Metzger <markus.t.metzger@intel.com>

Add a target for branch trace recording.  This will replace the btrace
commands added earlier in the patch series.

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.

I'm not quite sure when to use ui_out_~ functions and when to use
printf_unfiltered.  I tried to copy what others are doing, but I'm
not sure whether I got it right.

For the "record function-call-history" command, I assume that symbols can be
compared by comparing their pointers.  For comparing files, I use
compare_filenames_for_search.  I'm not sure whether this is the appropriate
function to use in this context.

2013-02-25 Markus Metzger  <markus.t.metzger@intel.com>

	* Makefile.in (SFILES): Add record-btrace.c
	(COMMON_OBS): Add record-btrace.o
	* record-btrace.c: New.
	* btrace.h (struct btrace_insn_iterator,
	struct btrace_function_iterator): New.
	(struct btrace_thread_info) <itrace, insn_iterator,
	call_iterator>: New fields.
	* common/btrace-common.h (struct btrace_inst): New.
	(btrace_inst_s): New typedef.


---
 gdb/Makefile.in            |    4 +-
 gdb/btrace.h               |   26 ++
 gdb/common/btrace-common.h |   20 +-
 gdb/record-btrace.c        | 1022 ++++++++++++++++++++++++++++++++++++++++++++
 4 files changed, 1067 insertions(+), 5 deletions(-)
 create mode 100644 gdb/record-btrace.c

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/btrace.h b/gdb/btrace.h
index 26fafc7..d56bfa4 100644
--- a/gdb/btrace.h
+++ b/gdb/btrace.h
@@ -29,6 +29,25 @@
 #include "btrace-common.h"
 
 struct thread_info;
+struct btrace_thread_info;
+
+/* Branch trace iteration state for "record instruction-history".  */
+struct btrace_insn_iterator
+{
+  /* The instruction index range [begin; end[ that has been covered last time.
+     If end < begin, the branch trace has just been updated.  */
+  unsigned int begin;
+  unsigned int end;
+};
+
+/* Branch trace iteration state for "record function-call-history".  */
+struct btrace_function_iterator
+{
+  /* The instruction index range [begin; end[ that has been covered last time.
+     If end < begin, the branch trace has just been updated.  */
+  unsigned int begin;
+  unsigned int end;
+};
 
 /* Branch trace information per thread.
 
@@ -47,6 +66,7 @@ struct btrace_thread_info
 
   /* The current branch trace for this thread.  */
   VEC (btrace_block_s) *btrace;
+  VEC (btrace_inst_s) *itrace;
 
   /* The current iterator position in the above trace vector.
      In additon to valid vector indices, the iterator can be:
@@ -54,6 +74,12 @@ struct btrace_thread_info
        -1            one before the head
        VEC_length()  one after the tail  */
   int iterator;
+
+  /* The instruction history iterator.  */
+  struct btrace_insn_iterator insn_iterator;
+
+  /* The function call history iterator.  */
+  struct btrace_function_iterator call_iterator;
 };
 
 /* Enable branch tracing for a thread.  */
diff --git a/gdb/common/btrace-common.h b/gdb/common/btrace-common.h
index 90372ba..c3f52f9 100644
--- a/gdb/common/btrace-common.h
+++ b/gdb/common/btrace-common.h
@@ -49,12 +49,26 @@ struct btrace_block
   CORE_ADDR end;
 };
 
-/* Branch trace is represented as a vector of branch trace blocks starting with
-   the most recent block.  */
+/* A branch trace instruction.
+
+   This represents a single instruction in a branch trace.  */
+struct btrace_inst
+{
+  /* The address of this instruction.  */
+  CORE_ADDR ip;
+};
+
+
+/* Branch trace may be represented as a vector of either:
+
+   - branch trace blocks starting with the most recent block.
+   - branch trace instructions starting with the oldest instruction.  */
 typedef struct btrace_block btrace_block_s;
+typedef struct btrace_inst btrace_inst_s;
 
-/* Define functions operating on a vector of branch trace blocks.  */
+/* Define functions operating on branch trace vectors.  */
 DEF_VEC_O (btrace_block_s);
+DEF_VEC_O (btrace_inst_s);
 
 /* Target specific branch trace information.  */
 struct btrace_target_info;
diff --git a/gdb/record-btrace.c b/gdb/record-btrace.c
new file mode 100644
index 0000000..e43b687
--- /dev/null
+++ b/gdb/record-btrace.c
@@ -0,0 +1,1022 @@
+/* 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 "regcache.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"
+
+/* 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;
+
+/* A recorded function segment.  */
+struct btrace_function
+{
+  /* The function symbol.  */
+  struct minimal_symbol *mfun;
+  struct symbol *fun;
+
+  /* The name of the function.  */
+  const char *function;
+
+  /* The name of the file in which the function is defined.  */
+  const char *filename;
+
+  /* The min and max line in the above file.  */
+  int begin;
+  int end;
+};
+
+/* A vector of recorded function segments.  */
+typedef struct btrace_function btr_fun_s;
+DEF_VEC_O (btr_fun_s);
+
+/* Debug output flags.  */
+enum record_btrace_debug_flag
+{
+  /* Print an overview of record-btrace functions.  */
+  debug_functions = 1 << 0,
+
+  /* Print details on "record function-call-history".  */
+  debug_call_history = 1 << 1
+};
+
+/* Print a record-btrace debug message.  Use do ... while (0) to avoid
+   ambiguities when used in if statements.  */
+
+#define DEBUG(mask, msg, args...)					\
+  do									\
+    {									\
+      if ((record_debug & mask) != 0)					\
+        fprintf_unfiltered (gdb_stdlog,					\
+			    "record-btrace: " msg "\n", ##args);	\
+    }									\
+  while (0)
+
+#define DEBUG_FUN(msg, args...) DEBUG (debug_functions, msg, ##args)
+#define DEBUG_CALL(msg, args...)				\
+  DEBUG (debug_call_history, "[hist: call] " msg, ##args)
+
+
+/* Initialize the instruction iterator.  */
+
+static void
+btrace_init_insn_iterator (struct btrace_thread_info *btinfo)
+{
+  DEBUG_FUN ("init insn iterator");
+
+  btinfo->insn_iterator.begin = 1;
+  btinfo->insn_iterator.end = 0;
+}
+
+/* Initialize the function call iterator.  */
+
+static void
+btrace_init_call_iterator (struct btrace_thread_info *btinfo)
+{
+  DEBUG_FUN ("init call iterator");
+
+  btinfo->call_iterator.begin = 1;
+  btinfo->call_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_FUN ("compute itrace");
+
+  itrace = NULL;
+  gdbarch = target_gdbarch ();
+  b = VEC_length (btrace_block_s, btrace);
+
+  while (b-- != 0)
+    {
+      btrace_block_s *block;
+      CORE_ADDR ip;
+
+      block = VEC_index (btrace_block_s, btrace, b);
+      ip = 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 < ip)
+	    {
+	      warning (_("Recorded trace may be corrupted."));
+	      break;
+	    }
+
+	  inst = VEC_safe_push (btrace_inst_s, itrace, NULL);
+	  inst->ip = ip;
+
+	  /* We're done once we pushed the instruction at the end.  */
+	  if (block->end == ip)
+	    break;
+
+	  size = gdb_insn_length (gdbarch, ip);
+
+	  /* Make sure we terminate if we fail to compute the size.  */
+	  if (size <= 0)
+	    {
+	      warning (_("Recorded trace may be incomplete."));
+	      break;
+	    }
+
+	  ip += size;
+	}
+    }
+
+  return itrace;
+}
+
+/* Fetch the branch trace for TP.  */
+
+static void
+fetch_btrace (struct thread_info *tp)
+{
+  struct btrace_thread_info *btinfo;
+
+  DEBUG_FUN ("fetch trace");
+
+  btinfo = &tp->btrace;
+  if (btinfo->target == NULL)
+    return;
+
+  if (!target_btrace_has_changed (btinfo->target))
+    return;
+
+  VEC_free (btrace_block_s, btinfo->btrace);
+  VEC_free (btrace_inst_s, btinfo->itrace);
+
+  btinfo->btrace = target_read_btrace (btinfo->target);
+
+  /* The first block ends at the current pc.  */
+  if (!VEC_empty (btrace_block_s, btinfo->btrace))
+    {
+      struct regcache *regcache;
+      struct btrace_block *head;
+
+      regcache = get_thread_regcache (tp->ptid);
+      head = VEC_index (btrace_block_s, btinfo->btrace, 0);
+      if (head != NULL && head->end == 0)
+	head->end = regcache_read_pc (regcache);
+    }
+
+  btinfo->itrace = compute_itrace (btinfo->btrace);
+
+  /* Initialize branch trace iterators.  */
+  btrace_init_insn_iterator (btinfo);
+  btrace_init_call_iterator (btinfo);
+}
+
+/* Update the branch trace for the current thread and return a pointer to its
+   branch trace information struct.
+
+   Fails if there is no thread or no trace.  */
+
+static struct btrace_thread_info *
+require_btrace (void)
+{
+  struct thread_info *tp;
+  struct btrace_thread_info *btinfo;
+
+  DEBUG_FUN ("require trace");
+
+  tp = find_thread_ptid (inferior_ptid);
+  btinfo = &tp->btrace;
+
+  if (tp == NULL)
+    error (_("No thread."));
+
+  fetch_btrace (tp);
+
+  if (VEC_empty (btrace_inst_s, btinfo->itrace))
+    error (_("No trace."));
+
+  return btinfo;
+}
+
+/* Enable branch tracing for one thread.  */
+
+static void
+record_btrace_enable (struct thread_info *tp)
+{
+  DEBUG_FUN ("enable thread %d (%s)", tp->num, target_pid_to_str (tp->ptid));
+
+  if (tp->btrace.target != NULL)
+    error (_("Thread %d (%s) is already traced."),
+	   tp->num, target_pid_to_str (tp->ptid));
+
+  tp->btrace.target = target_enable_btrace (tp->ptid);
+}
+
+/* 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)
+    record_btrace_enable (tp);
+
+  if (error.message != NULL)
+    warning ("%s", error.message);
+}
+
+/* Disable branch tracing for one thread.  */
+
+static void
+record_btrace_disable (struct thread_info *tp)
+{
+  struct btrace_thread_info *btp;
+
+  DEBUG_FUN ("disable thread %d (%s)", tp->num, target_pid_to_str (tp->ptid));
+
+  btp = &tp->btrace;
+  if (btp->target == NULL)
+    error (_("Thread %d (%s) is not traced."),
+	   tp->num, target_pid_to_str (tp->ptid));
+
+  target_disable_btrace (btp->target);
+  btp->target = NULL;
+
+  VEC_free (btrace_block_s, btp->btrace);
+}
+
+/* Callback function to enable branch tracing for one thread.  */
+
+static void
+record_btrace_disable_callback (void *arg)
+{
+  volatile struct gdb_exception error;
+  struct thread_info *tp;
+
+  tp = arg;
+
+  TRY_CATCH (error, RETURN_MASK_ERROR)
+    record_btrace_disable (tp);
+
+  if (error.message != NULL)
+    warning ("%s", error.message);
+}
+
+/* Enable automatic tracing of new threads.  */
+
+static void
+record_btrace_auto_enable (void)
+{
+  DEBUG_FUN ("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_FUN ("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_FUN ("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))
+      {
+	record_btrace_enable (tp);
+
+	(void) 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_close method of target record-btrace.  */
+
+static void
+record_btrace_close (int quitting)
+{
+  struct thread_info *tp;
+
+  DEBUG_FUN ("close");
+
+  /* Disable tracing for traced threads.  We use the ~_callback variant to
+     turn errors into warnings since we cannot afford to throw an error.  */
+  ALL_THREADS (tp)
+    if (tp->btrace.target)
+      record_btrace_disable_callback (tp);
+
+  record_btrace_auto_disable ();
+}
+
+/* The to_info_record method of target record-btrace.  */
+
+static void
+record_btrace_info (void)
+{
+  struct btrace_thread_info *btinfo;
+  unsigned int blocks, insts;
+
+  DEBUG_FUN ("info");
+
+  btinfo = require_btrace ();
+  blocks = VEC_length (btrace_block_s, btinfo->btrace);
+  insts = VEC_length (btrace_inst_s, btinfo->itrace);
+
+  printf_unfiltered (_("Recorded %u instructions in %u blocks.\n"),
+		     insts, blocks);
+}
+
+/* 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;
+  unsigned int idx;
+
+  DEBUG_FUN ("itrace (0x%x): [%u; %u[", flags, begin, end);
+
+  gdbarch = target_gdbarch ();
+
+  for (idx = begin; idx < end; ++idx)
+    {
+      struct btrace_inst *inst;
+
+      inst = VEC_index (btrace_inst_s, btinfo->itrace, idx);
+
+      /* Disassembly with '/m' flag may not produce the expected result.
+	 See PR gdb/11833.  */
+      gdb_disassembly (gdbarch, uiout, NULL, flags, 1, inst->ip, inst->ip + 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_FUN ("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_FUN ("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);
+}
+
+/* Initialize a recorded function segment.  */
+
+static void
+btrace_init_function (struct btrace_function *bfun,
+		      struct minimal_symbol *mfun,
+		      struct symbol *fun)
+{
+  memset (bfun, 0, sizeof (*bfun));
+
+  bfun->mfun = mfun;
+  bfun->fun = fun;
+  bfun->begin = INT_MAX;
+
+  /* Initialize file and function name based on the information we have.  */
+  if (fun != NULL)
+    {
+      bfun->filename = symtab_to_filename_for_display (fun->symtab);
+      bfun->function = SYMBOL_PRINT_NAME (fun);
+    }
+  else if (mfun != NULL)
+    {
+      bfun->filename = mfun->filename;
+      bfun->function = SYMBOL_PRINT_NAME (mfun);
+    }
+  else
+    internal_error (__FILE__, __LINE__, _("Require function."));
+
+  DEBUG_CALL ("init: fun = %s, file = %s, begin = %d, end = %d",
+	      bfun->function, bfun->filename ? bfun->filename : "<null>",
+	      bfun->begin, bfun->end);
+}
+
+/* Update the line information in a recorded function segment.  */
+
+static void
+btrace_function_update_lines (struct btrace_function *bfun, int line,
+			      CORE_ADDR ip)
+{
+  bfun->begin = min (bfun->begin, line);
+  bfun->end = max (bfun->end, line);
+
+  DEBUG_CALL ("lines at %s: begin: %d, end: %d",
+	      core_addr_to_string_nz (ip), bfun->begin, bfun->end);
+}
+
+/* Check if we should skip this file when generating the function call
+   history.
+   Update the recorded function segment.  */
+
+static int
+btrace_function_skip_file (struct btrace_function *bfun,
+			   const char *filename)
+{
+  /* Update the filename in case we didn't get it from the function symbol.  */
+  if (bfun->filename == NULL)
+    {
+      DEBUG_CALL ("file: '%s'", filename);
+
+      bfun->filename = filename;
+      return 0;
+    }
+
+  /* Check if we're still in the same file.  */
+  if (compare_filenames_for_search (bfun->filename, filename))
+    return 0;
+
+  /* We switched files, but not functions.  Skip this file.  */
+  DEBUG_CALL ("ignoring file '%s' for %s in %s.", filename,
+	      bfun->function, bfun->filename);
+  return 1;
+}
+
+/* Print a line in the function call history.  */
+
+static void
+btrace_print_function (struct ui_out *uiout, struct btrace_function *bfun,
+		       int flags)
+{
+  DEBUG_CALL ("print (0x%x): fun = %s, file = %s, begin = %d, end = %d", flags,
+	      bfun->function, bfun->filename ? bfun->filename : "<null>",
+	      bfun->begin, bfun->end);
+
+  if (flags & record_print_src_line)
+    {
+      const char *filename;
+      int begin, end;
+
+      filename = bfun->filename;
+      if (filename == NULL || *filename == 0)
+	filename = "<unknown>";
+
+      ui_out_field_string (uiout, "file", filename);
+
+      begin = bfun->begin;
+      end = bfun->end;
+
+      if (end != 0)
+	{
+	  ui_out_text (uiout, ":");
+	  ui_out_field_int (uiout, "min line", begin);
+
+	  if (end != begin)
+	    {
+	      ui_out_text (uiout, "-");
+	      ui_out_field_int (uiout, "max line", end);
+	    }
+	}
+
+      ui_out_text (uiout, "\t ");
+    }
+
+  ui_out_field_string (uiout, "function", bfun->function);
+  ui_out_text (uiout, "\n");
+}
+
+/* Compute the function call history.
+   Called for each instruction in the specified range.  */
+
+static void
+btrace_update_function (VEC (btr_fun_s) **bt, const struct btrace_inst *inst)
+{
+  struct btrace_function *bfun;
+  struct symtab_and_line line;
+  struct minimal_symbol *mfun;
+  struct symbol *fun;
+  CORE_ADDR ip;
+
+  mfun = NULL;
+  fun = NULL;
+  ip = inst->ip;
+
+  /* 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.
+     Not sure whether this is possible, at all.  */
+  fun = find_pc_function (ip);
+  mfun = lookup_minimal_symbol_by_pc (ip);
+
+  if (fun == NULL && mfun == NULL)
+    return;
+
+  /* Get the current function, if we already have one.  */
+  if (*bt != NULL)
+    bfun = VEC_last (btr_fun_s, *bt);
+  else
+    bfun = NULL;
+
+  /* If we're switching functions, we start over.  */
+  if (bfun == NULL || (fun != bfun->fun && mfun != bfun->mfun))
+    {
+      bfun = VEC_safe_push (btr_fun_s, *bt, NULL);
+
+      btrace_init_function (bfun, mfun, fun);
+    }
+
+  /* Let's see if we have source correlation, as well.  */
+  line = find_pc_line (ip, 0);
+  if (line.symtab != NULL)
+    {
+      const char *filename;
+
+      /* Without a filename, we ignore this instruction.  */
+      filename = symtab_to_filename_for_display (line.symtab);
+      if (filename == NULL)
+	return;
+
+      /* Do this check first to make sure we get a filename even if we don't
+	 have line information.  */
+      if (btrace_function_skip_file (bfun, filename))
+	return;
+
+      if (line.line == 0)
+	return;
+
+      btrace_function_update_lines (bfun, line.line, ip);
+    }
+}
+
+/* Print the function call history of an instruction trace section.
+
+   This would be faster on block trace level, but we might miss inlined
+   functions, in this case.  */
+
+static void
+btrace_call_history (struct btrace_thread_info *btinfo, struct ui_out *uiout,
+		     unsigned int begin, unsigned int end, unsigned int size,
+		     int flags)
+{
+  struct cleanup *cleanup;
+  struct btrace_function *bfun;
+  VEC (btr_fun_s) *history;
+  unsigned int idx;
+
+  if (size == -1)
+    DEBUG_FUN ("ftrace (0x%x): [%u; %u[", flags, begin, end);
+  else
+    DEBUG_FUN ("ftrace (0x%x): [%u; %u[, max %u", flags, begin, end, size);
+
+  history = NULL;
+  cleanup = make_cleanup (VEC_cleanup (btr_fun_s), &history);
+
+  for (idx = begin; idx < end && VEC_length (btr_fun_s, history) <= size; ++idx)
+    {
+      struct btrace_inst *inst;
+
+      inst = VEC_index (btrace_inst_s, btinfo->itrace, idx);
+      btrace_update_function (&history, inst);
+    }
+
+  /* Update end to how far we actually got.  */
+  end = idx;
+
+  /* If we reached the size limit, there will be an extra function segment.  */
+  if (size < VEC_length (btr_fun_s, history))
+    {
+      VEC_pop (btr_fun_s, history);
+      end -= 1;
+    }
+
+  /* Print the recorded function segments.  */
+  for (idx = 0; VEC_iterate (btr_fun_s, history, idx, bfun); ++idx)
+    btrace_print_function (uiout, bfun, flags);
+
+  do_cleanups (cleanup);
+
+  btinfo->call_iterator.begin = begin;
+  btinfo->call_iterator.end = end;
+}
+
+/* Print the function call history of an instruction trace section.
+
+   This function is similar to the above, except that it collects the
+   function call history in reverse order from end to begin.  It is
+   then printed in reverse, i.e. control-flow, order.  */
+
+static void
+btrace_reverse_call_history (struct btrace_thread_info *btinfo,
+			     struct ui_out *uiout, unsigned int begin,
+			     unsigned int end, unsigned int size, int flags)
+{
+  struct cleanup *cleanup;
+  VEC (btr_fun_s) *history;
+  unsigned int idx;
+
+  if (size == -1)
+    DEBUG_FUN ("ftrace-r itrace (0x%x): [%u; %u[", flags, begin, end);
+  else
+    DEBUG_FUN ("ftrace-r itrace (0x%x): [%u; %u[, max %u",
+	       flags, begin, end, size);
+
+  history = NULL;
+  cleanup = make_cleanup (VEC_cleanup (btr_fun_s), &history);
+
+  for (idx = end; begin < idx && VEC_length (btr_fun_s, history) <= size;)
+    {
+      struct btrace_inst *inst;
+
+      inst = VEC_index (btrace_inst_s, btinfo->itrace, --idx);
+      btrace_update_function (&history, inst);
+    }
+
+  /* Update begin to how far we actually got.  */
+  begin = idx;
+
+  /* If we reached the size limit, there will be an extra function segment.  */
+  if (size < VEC_length (btr_fun_s, history))
+    {
+      VEC_pop (btr_fun_s, history);
+      begin += 1;
+    }
+
+  /* Print the recorded function segments in reverse order.  */
+  for (idx = VEC_length (btr_fun_s, history); idx != 0;)
+    {
+      struct btrace_function *bfun;
+
+      bfun = VEC_index (btr_fun_s, history, --idx);
+      btrace_print_function (uiout, bfun, flags);
+    }
+
+  do_cleanups (cleanup);
+
+  btinfo->call_iterator.begin = begin;
+  btinfo->call_iterator.end = end;
+}
+
+/* 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,
+						       "call history");
+  btinfo = require_btrace ();
+  last = VEC_length (btrace_inst_s, btinfo->itrace);
+
+  begin = btinfo->call_iterator.begin;
+  end = btinfo->call_iterator.end;
+
+  DEBUG_FUN ("ftrace (0x%x): %d, prev: [%u; %u[", flags, size, begin, end);
+
+  context = abs (size);
+  if (context == 0)
+    error (_("Bad record function-call-history-size."));
+
+  /* We start at the end.  */
+  if (end < begin)
+    btrace_reverse_call_history (btinfo, uiout, 0, last, context, flags);
+  else if (size < 0)
+    {
+      if (begin == 0)
+	{
+	  printf_unfiltered (_("At the start of the branch trace record.\n"));
+
+	  btinfo->call_iterator.end = 0;
+	  return;
+	}
+
+      btrace_reverse_call_history (btinfo, uiout, 0, begin, context, flags);
+    }
+  else
+    {
+      if (end == last)
+	{
+	  printf_unfiltered (_("At the end of the branch trace record.\n"));
+
+	  btinfo->call_iterator.begin = last;
+	  return;
+	}
+
+      btrace_call_history (btinfo, uiout, end, last, context, flags);
+    }
+
+  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)
+{
+  struct btrace_thread_info *btinfo;
+  struct cleanup *uiout_cleanup;
+  struct ui_out *uiout;
+  unsigned int context, last, begin;
+
+  begin = (unsigned int) from;
+
+  DEBUG_FUN ("ftrace-from (0x%x): %u, %d", flags, begin, size);
+
+  uiout = current_uiout;
+  uiout_cleanup = make_cleanup_ui_out_tuple_begin_end (uiout,
+						       "call history");
+  btinfo = require_btrace ();
+  last = VEC_length (btrace_inst_s, btinfo->itrace);
+
+  context = abs (size);
+  if (context == 0)
+    error (_("Bad record function-call-history-size."));
+
+  /* Check for wrap-arounds.  */
+  if (begin != from)
+    error (_("Bad range."));
+
+  if (last <= begin)
+    error (_("Range out of bounds."));
+
+  if (size < 0)
+    btrace_reverse_call_history (btinfo, uiout, 0, begin, context, flags);
+  else
+    btrace_call_history (btinfo, uiout, begin, last, context, flags);
+
+  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;
+
+  begin = (unsigned int) from;
+  end = (unsigned int) to;
+
+  DEBUG_FUN ("bt range (0x%x): [%u; %u[", flags, begin, end);
+
+  uiout = current_uiout;
+  uiout_cleanup = make_cleanup_ui_out_tuple_begin_end (uiout,
+						       "call history");
+  btinfo = require_btrace ();
+  last = VEC_length (btrace_inst_s, btinfo->itrace);
+
+  /* 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_call_history (btinfo, uiout, begin, end, -1, flags);
+
+  do_cleanups (uiout_cleanup);
+}
+
+/* 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_info_record = record_btrace_info;
+  ops->to_insn_history = record_btrace_insn_history;
+  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);
+}
-- 
1.7.1