[PATCH v4 01/10] btrace: Introduce auxiliary instructions.

[PATCH v4 01/10] btrace: Introduce auxiliary instructions.

[Felix Willgerodt]

Auxiliary instructions are pseudo instructions pointing to auxiliary data.
This auxiliary data can be printed in all commands displaying (record
function-call-history, record instruction-history) or stepping through
(stepi etc.) the execution history, which will be introduced in the next
commits.

This patch is in preparation for the new ptwrite feature, which is based on
auxiliary instructions.
---
 gdb/btrace.c        |  2 ++
 gdb/btrace.h        | 24 +++++++++++++++++++++---
 gdb/doc/gdb.texinfo |  4 ++++
 3 files changed, 27 insertions(+), 3 deletions(-)

diff --git a/gdb/btrace.c b/gdb/btrace.c
index c4f0d4911ab..3305ebfb58f 100644
--- a/gdb/btrace.c
+++ b/gdb/btrace.c
@@ -1823,6 +1823,8 @@ btrace_clear_history (struct btrace_thread_info *btinfo)
   btinfo->insn_history = NULL;
   btinfo->call_history = NULL;
   btinfo->replay = NULL;
+
+  btinfo->aux_data.clear ();
 }
 
 /* Clear the branch trace maintenance histories in BTINFO.  */
diff --git a/gdb/btrace.h b/gdb/btrace.h
index 0fcf669597a..be4ce424ed5 100644
--- a/gdb/btrace.h
+++ b/gdb/btrace.h
@@ -52,7 +52,10 @@ enum btrace_insn_class
   BTRACE_INSN_RETURN,
 
   /* The instruction is an unconditional jump.  */
-  BTRACE_INSN_JUMP
+  BTRACE_INSN_JUMP,
+
+  /* The instruction is a pseudo instruction containing auxiliary data.  */
+  BTRACE_INSN_AUX
 };
 
 /* Instruction flags.  */
@@ -68,8 +71,19 @@ DEF_ENUM_FLAGS_TYPE (enum btrace_insn_flag, btrace_insn_flags);
    This represents a single instruction in a branch trace.  */
 struct btrace_insn
 {
-  /* The address of this instruction.  */
-  CORE_ADDR pc;
+  union
+  {
+    /* The address of this instruction.  Applies to btrace_insn with
+       iclass == BTRACE_INSN_OTHER or
+       iclass == BTRACE_INSN_CALL or
+       iclass == BTRACE_INSN_RETURN or
+       iclass == BTRACE_INSN_JUMP.  */
+    CORE_ADDR pc;
+
+    /* Index into btrace_info::aux_data.  Applies to btrace_insn with
+       iclass == BTRACE_INSN_AUX.  */
+    uint64_t aux_data_index;
+  };
 
   /* The size of this instruction in bytes.  */
   gdb_byte size;
@@ -330,6 +344,10 @@ struct btrace_thread_info
      function segment i will be at index (i - 1).  */
   std::vector<btrace_function> functions;
 
+  /* Optional auxiliary information that is printed in all commands
+     displaying or stepping through the execution history.  */
+  std::vector<std::string> aux_data;
+
   /* The function level offset.  When added to each function's LEVEL,
      this normalizes the function levels such that the smallest level
      becomes zero.  */
diff --git a/gdb/doc/gdb.texinfo b/gdb/doc/gdb.texinfo
index 38ad2ac32b0..ec45055e914 100644
--- a/gdb/doc/gdb.texinfo
+++ b/gdb/doc/gdb.texinfo
@@ -7485,6 +7485,10 @@ Moxie, PowerPC, PowerPC64, S/390, and x86 (i386/amd64) running
 GNU/Linux.  Process record and replay can be used both when native
 debugging, and when remote debugging via @code{gdbserver}.
 
+When recording an inferior, @value{GDBN} may print additional auxiliary
+information during stepping commands and commands displaying the execution
+history.
+
 For architecture environments that support process record and replay,
 @value{GDBN} provides the following commands:
 
-- 
2.34.1

Intel Deutschland GmbH
Registered Address: Am Campeon 10, 85579 Neubiberg, Germany
Tel: +49 89 99 8853-0, www.intel.de <http://www.intel.de>
Managing Directors: Christin Eisenschmid, Sharon Heck, Tiffany Doon Silva  
Chairperson of the Supervisory Board: Nicole Lau
Registered Office: Munich
Commercial Register: Amtsgericht Muenchen HRB 186928

[PATCH v4 02/10] btrace: Enable auxiliary instructions in record instruction-history.

[Felix Willgerodt]

Print the auxiliary data when a btrace_insn of type BTRACE_INSN_AUX
is encountered in the instruction-history.  Printing is active by default,
it can be silenced with the /a modifier.

This patch is in preparation for the new ptwrite feature, which is based on
auxiliary instructions.
---
 gdb/disasm-flags.h  |  1 +
 gdb/doc/gdb.texinfo |  3 +++
 gdb/record-btrace.c | 14 ++++++++++++++
 gdb/record.c        |  5 +++++
 4 files changed, 23 insertions(+)

diff --git a/gdb/disasm-flags.h b/gdb/disasm-flags.h
index 025b6893941..4c920971d99 100644
--- a/gdb/disasm-flags.h
+++ b/gdb/disasm-flags.h
@@ -33,6 +33,7 @@ enum gdb_disassembly_flag
     DISASSEMBLY_OMIT_PC = (0x1 << 4),
     DISASSEMBLY_SOURCE = (0x1 << 5),
     DISASSEMBLY_SPECULATIVE = (0x1 << 6),
+    DISASSEMBLY_OMIT_AUX_INSN = (0x1 << 7),
   };
 DEF_ENUM_FLAGS_TYPE (enum gdb_disassembly_flag, gdb_disassembly_flags);
 
diff --git a/gdb/doc/gdb.texinfo b/gdb/doc/gdb.texinfo
index ec45055e914..da1645a1378 100644
--- a/gdb/doc/gdb.texinfo
+++ b/gdb/doc/gdb.texinfo
@@ -7901,6 +7901,9 @@ To better align the printed instructions when the trace contains
 instructions from more than one function, the function name may be
 omitted by specifying the @code{/f} modifier.
 
+Printing auxiliary information is enabled by default and can be
+omitted with the @code{/a} modifier.
+
 Speculatively executed instructions are prefixed with @samp{?}.  This
 feature is not available for all recording formats.
 
diff --git a/gdb/record-btrace.c b/gdb/record-btrace.c
index 373d82b8b99..2a0e0033c8d 100644
--- a/gdb/record-btrace.c
+++ b/gdb/record-btrace.c
@@ -821,6 +821,20 @@ btrace_insn_history (struct ui_out *uiout,
 	  btrace_ui_out_decode_error (uiout, btrace_insn_get_error (&it),
 				      conf->format);
 	}
+      else if (insn->iclass == BTRACE_INSN_AUX)
+	{
+	  if ((flags & DISASSEMBLY_OMIT_AUX_INSN) != 0)
+	    continue;
+
+	  uiout->field_fmt ("insn-number", "%u", btrace_insn_number (&it));
+	  uiout->text ("\t");
+	  uiout->spaces (3);
+	  uiout->text ("[");
+	  uiout->field_fmt (
+	      "aux-data", "%s",
+	      it.btinfo->aux_data.at (insn->aux_data_index).c_str ());
+	  uiout->text ("]\n");
+	}
       else
 	{
 	  struct disasm_insn dinsn;
diff --git a/gdb/record.c b/gdb/record.c
index 17a5df262bd..94b8c7b7ed3 100644
--- a/gdb/record.c
+++ b/gdb/record.c
@@ -486,6 +486,9 @@ get_insn_history_modifiers (const char **arg)
 
 	  switch (*args)
 	    {
+	    case 'a':
+	      modifiers |= DISASSEMBLY_OMIT_AUX_INSN;
+	      break;
 	    case 'm':
 	    case 's':
 	      modifiers |= DISASSEMBLY_SOURCE;
@@ -853,6 +856,8 @@ With a /m or /s modifier, source lines are included (if available).\n\
 With a /r modifier, raw instructions in hex are included.\n\
 With a /f modifier, function names are omitted.\n\
 With a /p modifier, current position markers are omitted.\n\
+With a /a modifier, omits output of auxiliary data, which is enabled \
+by default.\n\
 With no argument, disassembles ten more instructions after the previous \
 disassembly.\n\
 \"record instruction-history -\" disassembles ten instructions before a \
-- 
2.34.1

Intel Deutschland GmbH
Registered Address: Am Campeon 10, 85579 Neubiberg, Germany
Tel: +49 89 99 8853-0, www.intel.de <http://www.intel.de>
Managing Directors: Christin Eisenschmid, Sharon Heck, Tiffany Doon Silva  
Chairperson of the Supervisory Board: Nicole Lau
Registered Office: Munich
Commercial Register: Amtsgericht Muenchen HRB 186928

[PATCH v4 03/10] btrace: Enable auxiliary instructions in record function-call-history.

[Felix Willgerodt]

Print the auxiliary data when a btrace_insn of type BTRACE_INSN_AUX
is encountered in the function-call-history.  Printing is
active by default, it can be silenced with the /a modifier.

This patch is in preparation for the new ptwrite feature, which is based on
auxiliary instructions.
---
 gdb/btrace.h        |  6 +++++-
 gdb/doc/gdb.texinfo |  5 +++--
 gdb/record-btrace.c | 21 +++++++++++++++++++++
 gdb/record.c        |  5 +++++
 gdb/record.h        |  5 ++++-
 5 files changed, 38 insertions(+), 4 deletions(-)

diff --git a/gdb/btrace.h b/gdb/btrace.h
index be4ce424ed5..69ce2f3330d 100644
--- a/gdb/btrace.h
+++ b/gdb/btrace.h
@@ -105,7 +105,11 @@ enum btrace_function_flag
 
   /* The 'up' link points to a tail call.  This obviously only makes sense
      if bfun_up_links_to_ret is clear.  */
-  BFUN_UP_LINKS_TO_TAILCALL = (1 << 1)
+  BFUN_UP_LINKS_TO_TAILCALL = (1 << 1),
+
+  /* Indicates that at least one auxiliary instruction is in the current
+     function segment.  */
+  BFUN_AUX_DECODED = (1 << 2)
 };
 DEF_ENUM_FLAGS_TYPE (enum btrace_function_flag, btrace_function_flags);
 
diff --git a/gdb/doc/gdb.texinfo b/gdb/doc/gdb.texinfo
index da1645a1378..fa3c8cb1cf3 100644
--- a/gdb/doc/gdb.texinfo
+++ b/gdb/doc/gdb.texinfo
@@ -7957,8 +7957,9 @@ that function, the source lines for this instruction sequence (if the
 @code{/l} modifier is specified), and the instructions numbers that form
 the sequence (if the @code{/i} modifier is specified).  The function names
 are indented to reflect the call stack depth if the @code{/c} modifier is
-specified.  The @code{/l}, @code{/i}, and @code{/c} modifiers can be given
-together.
+specified.  Printing auxiliary information is enabled by default and can be
+omitted with the @code{/a} modifier.  The @code{/l}, @code{/i}, @code{/a},
+and @code{/c} modifiers can be given together.
 
 @smallexample
 (@value{GDBP}) @b{list 1, 10}
diff --git a/gdb/record-btrace.c b/gdb/record-btrace.c
index 2a0e0033c8d..970b55c18f7 100644
--- a/gdb/record-btrace.c
+++ b/gdb/record-btrace.c
@@ -1153,6 +1153,23 @@ btrace_get_bfun_name (const struct btrace_function *bfun)
     return "??";
 }
 
+static void
+btrace_print_aux_insn (struct ui_out *uiout,
+		       const struct btrace_function *bfun,
+		       const struct btrace_thread_info *btinfo)
+{
+  for (const btrace_insn &insn : bfun->insn)
+    {
+      if (insn.iclass == BTRACE_INSN_AUX)
+	{
+	  uiout->text ("\t\t[");
+	  uiout->field_fmt ("aux-data", "%s",
+			    btinfo->aux_data.at (insn.aux_data_index).c_str ());
+	  uiout->text ("]\n");
+	}
+    }
+}
+
 /* Disassemble a section of the recorded function trace.  */
 
 static void
@@ -1228,6 +1245,10 @@ btrace_call_history (struct ui_out *uiout,
 	}
 
       uiout->text ("\n");
+
+      if (((flags & RECORD_DONT_PRINT_AUX) == 0)
+	  && ((bfun->flags & BFUN_AUX_DECODED) != 0))
+	btrace_print_aux_insn(uiout, bfun, btinfo);
     }
 }
 
diff --git a/gdb/record.c b/gdb/record.c
index 94b8c7b7ed3..956475b57c7 100644
--- a/gdb/record.c
+++ b/gdb/record.c
@@ -636,6 +636,9 @@ get_call_history_modifiers (const char **arg)
 	    case 'c':
 	      modifiers |= RECORD_PRINT_INDENT_CALLS;
 	      break;
+	    case 'a':
+	      modifiers |= RECORD_DONT_PRINT_AUX;
+	      break;
 	    default:
 	      error (_("Invalid modifier: %c."), *args);
 	    }
@@ -880,6 +883,8 @@ Without modifiers, it prints the function name.\n\
 With a /l modifier, the source file and line number range is included.\n\
 With a /i modifier, the instruction number range is included.\n\
 With a /c modifier, the output is indented based on the call stack depth.\n\
+With a /a modifier, omits output of auxiliary data, which is enabled \
+by default.\n\
 With no argument, prints ten more lines after the previous ten-line print.\n\
 \"record function-call-history -\" prints ten lines before a previous ten-line \
 print.\n\
diff --git a/gdb/record.h b/gdb/record.h
index 0fbca9d44ce..d882f313c1d 100644
--- a/gdb/record.h
+++ b/gdb/record.h
@@ -62,7 +62,10 @@ enum record_print_flag
   RECORD_PRINT_INSN_RANGE = (1 << 1),
 
   /* Indent based on call stack depth (if applicable).  */
-  RECORD_PRINT_INDENT_CALLS = (1 << 2)
+  RECORD_PRINT_INDENT_CALLS = (1 << 2),
+
+  /* Deactivate printing auxiliary data (if applicable).  */
+  RECORD_DONT_PRINT_AUX = (1 << 3)
 };
 DEF_ENUM_FLAGS_TYPE (enum record_print_flag, record_print_flags);
 
-- 
2.34.1

Intel Deutschland GmbH
Registered Address: Am Campeon 10, 85579 Neubiberg, Germany
Tel: +49 89 99 8853-0, www.intel.de <http://www.intel.de>
Managing Directors: Christin Eisenschmid, Sharon Heck, Tiffany Doon Silva  
Chairperson of the Supervisory Board: Nicole Lau
Registered Office: Munich
Commercial Register: Amtsgericht Muenchen HRB 186928

[PATCH v4 04/10] btrace: Handle stepping and goto for auxiliary instructions.

[Felix Willgerodt]

Print the auxiliary data when stepping. Don't allow to goto an auxiliary
instruction.

This patch is in preparation for the new ptwrite feature, which is based on
auxiliary instructions.
---
 gdb/record-btrace.c | 68 ++++++++++++++++++++++++++++++++++++---------
 1 file changed, 55 insertions(+), 13 deletions(-)

diff --git a/gdb/record-btrace.c b/gdb/record-btrace.c
index 970b55c18f7..1bfb9c1d876 100644
--- a/gdb/record-btrace.c
+++ b/gdb/record-btrace.c
@@ -2375,9 +2375,13 @@ record_btrace_single_step_forward (struct thread_info *tp)
     return btrace_step_stopped ();
 
   /* Skip gaps during replay.  If we end up at a gap (at the end of the trace),
-     jump back to the instruction at which we started.  */
+     jump back to the instruction at which we started.  If we're stepping a
+     BTRACE_INSN_AUX instruction, print the auxiliary data and skip the
+     instruction.  */
+
   start = *replay;
-  do
+
+  for (;;)
     {
       unsigned int steps;
 
@@ -2385,12 +2389,27 @@ record_btrace_single_step_forward (struct thread_info *tp)
 	 of the execution history.  */
       steps = btrace_insn_next (replay, 1);
       if (steps == 0)
+        {
+          *replay = start;
+          return btrace_step_no_history ();
+        }
+
+      const struct btrace_insn *insn = btrace_insn_get (replay);
+      if (insn == nullptr)
+	continue;
+
+      /* If we're stepping a BTRACE_INSN_AUX instruction, print the auxiliary
+	 data and skip the instruction.  */
+      if (insn->iclass == BTRACE_INSN_AUX)
 	{
-	  *replay = start;
-	  return btrace_step_no_history ();
+	  gdb_printf ("[%s]\n",
+		      btinfo->aux_data.at (insn->aux_data_index).c_str ());
+	  continue;
 	}
+
+      /* We have an instruction, we are done.  */
+      break;
     }
-  while (btrace_insn_get (replay) == NULL);
 
   /* Determine the end of the instruction trace.  */
   btrace_insn_end (&end, btinfo);
@@ -2421,9 +2440,12 @@ record_btrace_single_step_backward (struct thread_info *tp)
 
   /* If we can't step any further, we reached the end of the history.
      Skip gaps during replay.  If we end up at a gap (at the beginning of
-     the trace), jump back to the instruction at which we started.  */
+     the trace), jump back to the instruction at which we started.
+     If we're stepping a BTRACE_INSN_AUX instruction, print the auxiliary
+     data and skip the instruction.  */
   start = *replay;
-  do
+
+  for (;;)
     {
       unsigned int steps;
 
@@ -2433,8 +2455,22 @@ record_btrace_single_step_backward (struct thread_info *tp)
 	  *replay = start;
 	  return btrace_step_no_history ();
 	}
+
+      const struct btrace_insn *insn = btrace_insn_get (replay);
+      if (insn == nullptr)
+	continue;
+
+      /* Check if we're stepping a BTRACE_INSN_AUX instruction and skip it.  */
+      if (insn->iclass == BTRACE_INSN_AUX)
+	{
+	  gdb_printf ("[%s]\n",
+		      btinfo->aux_data.at (insn->aux_data_index).c_str ());
+	  continue;
+	}
+
+      /* We have an instruction, we are done.  */
+      break;
     }
-  while (btrace_insn_get (replay) == NULL);
 
   /* Check if we're stepping a breakpoint.
 
@@ -2856,25 +2892,31 @@ record_btrace_target::goto_record_end ()
 /* The goto_record method of target record-btrace.  */
 
 void
-record_btrace_target::goto_record (ULONGEST insn)
+record_btrace_target::goto_record (ULONGEST insn_number)
 {
   struct thread_info *tp;
   struct btrace_insn_iterator it;
   unsigned int number;
   int found;
 
-  number = insn;
+  number = insn_number;
 
   /* Check for wrap-arounds.  */
-  if (number != insn)
+  if (number != insn_number)
     error (_("Instruction number out of range."));
 
   tp = require_btrace_thread ();
 
   found = btrace_find_insn_by_number (&it, &tp->btrace, number);
 
-  /* Check if the instruction could not be found or is a gap.  */
-  if (found == 0 || btrace_insn_get (&it) == NULL)
+  /* Check if the instruction could not be found or is a gap or an
+     auxilliary instruction.  */
+  if (found == 0)
+    error (_("No such instruction."));
+
+  const struct btrace_insn *insn = btrace_insn_get (&it);
+
+  if ((insn == NULL) || (insn->iclass == BTRACE_INSN_AUX))
     error (_("No such instruction."));
 
   record_btrace_set_replay (tp, &it);
-- 
2.34.1

Intel Deutschland GmbH
Registered Address: Am Campeon 10, 85579 Neubiberg, Germany
Tel: +49 89 99 8853-0, www.intel.de <http://www.intel.de>
Managing Directors: Christin Eisenschmid, Sharon Heck, Tiffany Doon Silva  
Chairperson of the Supervisory Board: Nicole Lau
Registered Office: Munich
Commercial Register: Amtsgericht Muenchen HRB 186928

[PATCH v4 05/10] python: Introduce gdb.RecordAuxiliary class.

[Felix Willgerodt]

Auxiliary instructions are no real instructions and get their own object
class, similar to gaps. gdb.Record.instruction_history is now possibly a
list of gdb.RecordInstruction, gdb.RecordGap or gdb.RecordAuxiliary
objects.

This patch is in preparation for the new ptwrite feature, which is based on
auxiliary instructions.
---
 gdb/doc/python.texi           | 13 +++++++
 gdb/python/py-record-btrace.c | 34 ++++++++++------
 gdb/python/py-record.c        | 73 ++++++++++++++++++++++++++++++++++-
 gdb/python/py-record.h        |  3 ++
 4 files changed, 110 insertions(+), 13 deletions(-)

diff --git a/gdb/doc/python.texi b/gdb/doc/python.texi
index cb5283e03c0..142dbc719a4 100644
--- a/gdb/doc/python.texi
+++ b/gdb/doc/python.texi
@@ -3835,6 +3835,19 @@ the current recording method.
 A human readable string with the reason for the gap.
 @end defvar
 
+Some @value{GDBN} features write auxiliary information into the execution
+history.  This information is represented by a @code{gdb.RecordAuxiliary} object
+in the instruction list.  It has the following attributes:
+
+@defvar RecordAuxiliary.number
+An integer identifying this auxiliary.  @code{number} corresponds to the numbers
+seen in @code{record instruction-history} (@pxref{Process Record and Replay}).
+@end defvar
+
+@defvar RecordAuxiliary.data
+A string representation of the auxiliary data.
+@end defvar
+
 A @code{gdb.RecordFunctionSegment} object has the following attributes:
 
 @defvar RecordFunctionSegment.number
diff --git a/gdb/python/py-record-btrace.c b/gdb/python/py-record-btrace.c
index 85401010f0a..e08619ffd64 100644
--- a/gdb/python/py-record-btrace.c
+++ b/gdb/python/py-record-btrace.c
@@ -45,7 +45,8 @@ struct btpy_list_object {
   /* Stride size.  */
   Py_ssize_t step;
 
-  /* Either &BTPY_CALL_TYPE or &RECPY_INSN_TYPE.  */
+  /* Either &recpy_func_type, &recpy_insn_type, &recpy_aux_type or
+     &recpy_gap_type.  */
   PyTypeObject* element_type;
 };
 
@@ -141,10 +142,11 @@ btrace_func_from_recpy_func (const PyObject * const pyobject)
 }
 
 /* Looks at the recorded item with the number NUMBER and create a
-   gdb.RecordInstruction or gdb.RecordGap object for it accordingly.  */
+   gdb.RecordInstruction, gdb.RecordGap or gdb.RecordAuxiliary object
+   for it accordingly.  */
 
 static PyObject *
-btpy_insn_or_gap_new (thread_info *tinfo, Py_ssize_t number)
+btpy_item_new (thread_info *tinfo, Py_ssize_t number)
 {
   btrace_insn_iterator iter;
   int err_code;
@@ -163,6 +165,13 @@ btpy_insn_or_gap_new (thread_info *tinfo, Py_ssize_t number)
       return recpy_gap_new (err_code, err_string, number);
     }
 
+  const struct btrace_insn *insn = btrace_insn_get (&iter);
+  gdb_assert (insn != nullptr);
+
+  if (insn->iclass == BTRACE_INSN_AUX)
+    return recpy_aux_new (
+	iter.btinfo->aux_data.at (insn->aux_data_index).c_str (), number);
+
   return recpy_insn_new (tinfo, RECORD_METHOD_BTRACE, number);
 }
 
@@ -441,8 +450,10 @@ btpy_list_length (PyObject *self)
 }
 
 /* Implementation of
-   BtraceList.__getitem__ (self, key) -> BtraceInstruction and
-   BtraceList.__getitem__ (self, key) -> BtraceFunctionCall.  */
+   BtraceList.__getitem__ (self, key) -> BtraceInstruction,
+   BtraceList.__getitem__ (self, key) -> BtraceFunctionCall,
+   BtraceList.__getitem__ (self, key) -> BtraceAuxilliary and
+   BtraceList.__getitem__ (self, key) -> BtraceGap.  */
 
 static PyObject *
 btpy_list_item (PyObject *self, Py_ssize_t index)
@@ -456,10 +467,10 @@ btpy_list_item (PyObject *self, Py_ssize_t index)
 
   number = obj->first + (obj->step * index);
 
-  if (obj->element_type == &recpy_insn_type)
-    return recpy_insn_new (obj->thread, RECORD_METHOD_BTRACE, number);
-  else
+  if (obj->element_type == &recpy_func_type)
     return recpy_func_new (obj->thread, RECORD_METHOD_BTRACE, number);
+  else
+    return btpy_item_new (obj->thread, number);
 }
 
 /* Implementation of BtraceList.__getitem__ (self, slice) -> BtraceList.  */
@@ -646,8 +657,7 @@ recpy_bt_replay_position (PyObject *self, void *closure)
   if (tinfo->btrace.replay == NULL)
     Py_RETURN_NONE;
 
-  return btpy_insn_or_gap_new (tinfo,
-			       btrace_insn_number (tinfo->btrace.replay));
+  return btpy_item_new (tinfo, btrace_insn_number (tinfo->btrace.replay));
 }
 
 /* Implementation of
@@ -669,7 +679,7 @@ recpy_bt_begin (PyObject *self, void *closure)
     Py_RETURN_NONE;
 
   btrace_insn_begin (&iterator, &tinfo->btrace);
-  return btpy_insn_or_gap_new (tinfo, btrace_insn_number (&iterator));
+  return btpy_item_new (tinfo, btrace_insn_number (&iterator));
 }
 
 /* Implementation of
@@ -691,7 +701,7 @@ recpy_bt_end (PyObject *self, void *closure)
     Py_RETURN_NONE;
 
   btrace_insn_end (&iterator, &tinfo->btrace);
-  return btpy_insn_or_gap_new (tinfo, btrace_insn_number (&iterator));
+  return btpy_item_new (tinfo, btrace_insn_number (&iterator));
 }
 
 /* Implementation of
diff --git a/gdb/python/py-record.c b/gdb/python/py-record.c
index 51084dfac72..47bbd290144 100644
--- a/gdb/python/py-record.c
+++ b/gdb/python/py-record.c
@@ -49,6 +49,12 @@ static PyTypeObject recpy_gap_type = {
   PyVarObject_HEAD_INIT (NULL, 0)
 };
 
+/* Python RecordAuxiliary type.  */
+
+PyTypeObject recpy_aux_type = {
+  PyVarObject_HEAD_INIT (nullptr, 0)
+};
+
 /* Python RecordGap object.  */
 struct recpy_gap_object
 {
@@ -64,6 +70,18 @@ struct recpy_gap_object
   Py_ssize_t number;
 };
 
+/* Python RecordAuxiliary object.  */
+typedef struct
+{
+  PyObject_HEAD
+
+  /* Auxiliary data.  */
+  const char *data;
+
+  /* Element number.  */
+  Py_ssize_t number;
+} recpy_aux_object;
+
 /* Implementation of record.method.  */
 
 static PyObject *
@@ -477,6 +495,43 @@ recpy_gap_reason_string (PyObject *self, void *closure)
   return PyUnicode_FromString (obj->reason_string);
 }
 
+/* Create a new gdb.Auxiliary object.  */
+
+PyObject *
+recpy_aux_new (const char *data, Py_ssize_t number)
+{
+  recpy_aux_object * const obj = PyObject_New (recpy_aux_object,
+					       &recpy_aux_type);
+
+  if (obj == nullptr)
+   return nullptr;
+
+  obj->data = data;
+  obj->number = number;
+
+  return (PyObject *) obj;
+}
+
+/* Implementation of Auxiliary.number [int].  */
+
+static PyObject *
+recpy_aux_number (PyObject *self, void *closure)
+{
+  const recpy_aux_object * const obj = (const recpy_aux_object *) self;
+
+  return gdb_py_object_from_longest (obj->number).release ();
+}
+
+/* Implementation of Auxiliary.data [str].  */
+
+static PyObject *
+recpy_aux_data (PyObject *self, void *closure)
+{
+  const recpy_aux_object * const obj = (const recpy_aux_object *) self;
+
+  return PyUnicode_FromString (obj->data);
+}
+
 /* Record method list.  */
 
 static PyMethodDef recpy_record_methods[] = {
@@ -542,6 +597,14 @@ static gdb_PyGetSetDef recpy_gap_getset[] = {
   { NULL }
 };
 
+/* RecordAuxiliary member list.  */
+
+static gdb_PyGetSetDef recpy_aux_getset[] = {
+  { "number", recpy_aux_number, nullptr, "element number", nullptr},
+  { "data", recpy_aux_data, nullptr, "data", nullptr},
+  { nullptr }
+};
+
 /* Sets up the record API in the gdb module.  */
 
 int
@@ -581,10 +644,18 @@ gdbpy_initialize_record (void)
   recpy_gap_type.tp_doc = "GDB recorded gap object";
   recpy_gap_type.tp_getset = recpy_gap_getset;
 
+  recpy_aux_type.tp_new = PyType_GenericNew;
+  recpy_aux_type.tp_flags = Py_TPFLAGS_DEFAULT;
+  recpy_aux_type.tp_basicsize = sizeof (recpy_aux_object);
+  recpy_aux_type.tp_name = "gdb.RecordAuxiliary";
+  recpy_aux_type.tp_doc = "GDB recorded auxiliary object";
+  recpy_aux_type.tp_getset = recpy_aux_getset;
+
   if (PyType_Ready (&recpy_record_type) < 0
       || PyType_Ready (&recpy_insn_type) < 0
       || PyType_Ready (&recpy_func_type) < 0
-      || PyType_Ready (&recpy_gap_type) < 0)
+      || PyType_Ready (&recpy_gap_type) < 0
+      || PyType_Ready (&recpy_aux_type) < 0)
     return -1;
   else
     return 0;
diff --git a/gdb/python/py-record.h b/gdb/python/py-record.h
index 2c8cfd6e4a5..d1d784e758e 100644
--- a/gdb/python/py-record.h
+++ b/gdb/python/py-record.h
@@ -71,4 +71,7 @@ extern PyObject *recpy_func_new (thread_info *thread, enum record_method method,
 extern PyObject *recpy_gap_new (int reason_code, const char *reason_string,
 				Py_ssize_t number);
 
+/* Create a new gdb.RecordGap object.  */
+extern PyObject *recpy_aux_new (const char *data, Py_ssize_t number);
+
 #endif /* PYTHON_PY_RECORD_H */
-- 
2.34.1

Intel Deutschland GmbH
Registered Address: Am Campeon 10, 85579 Neubiberg, Germany
Tel: +49 89 99 8853-0, www.intel.de <http://www.intel.de>
Managing Directors: Christin Eisenschmid, Sharon Heck, Tiffany Doon Silva  
Chairperson of the Supervisory Board: Nicole Lau
Registered Office: Munich
Commercial Register: Amtsgericht Muenchen HRB 186928

[PATCH v4 06/10] python: Add clear() to gdb.Record.

[Felix Willgerodt]

This function allows to clear the trace data from python, forcing to
re-decode the trace for successive commands.
---
 gdb/doc/python.texi                           |  5 +++++
 gdb/python/py-record-btrace.c                 | 13 +++++++++++++
 gdb/python/py-record-btrace.h                 |  3 +++
 gdb/python/py-record.c                        | 16 ++++++++++++++++
 gdb/testsuite/gdb.python/py-record-btrace.exp |  6 +++++-
 5 files changed, 42 insertions(+), 1 deletion(-)

diff --git a/gdb/doc/python.texi b/gdb/doc/python.texi
index 142dbc719a4..707aa5c3ee3 100644
--- a/gdb/doc/python.texi
+++ b/gdb/doc/python.texi
@@ -3779,6 +3779,11 @@ A @code{gdb.Record} object has the following methods:
 Move the replay position to the given @var{instruction}.
 @end defun
 
+@defun Record.clear ()
+Clear the trace data of the current recording.  This forces re-decoding of the
+trace for successive commands.
+@end defun
+
 The common @code{gdb.Instruction} class that recording method specific
 instruction objects inherit from, has the following attributes:
 
diff --git a/gdb/python/py-record-btrace.c b/gdb/python/py-record-btrace.c
index e08619ffd64..8b3ae8c3fab 100644
--- a/gdb/python/py-record-btrace.c
+++ b/gdb/python/py-record-btrace.c
@@ -801,6 +801,19 @@ recpy_bt_goto (PyObject *self, PyObject *args)
   Py_RETURN_NONE;
 }
 
+/* Implementation of BtraceRecord.clear (self) -> None.  */
+
+PyObject *
+recpy_bt_clear (PyObject *self, PyObject *args)
+{
+  const recpy_record_object * const record = (recpy_record_object *) self;
+  thread_info *const tinfo = record->thread;
+
+  btrace_clear (tinfo);
+
+  Py_RETURN_NONE;
+}
+
 /* BtraceList methods.  */
 
 static PyMethodDef btpy_list_methods[] =
diff --git a/gdb/python/py-record-btrace.h b/gdb/python/py-record-btrace.h
index 8ef26c860db..b25b121d255 100644
--- a/gdb/python/py-record-btrace.h
+++ b/gdb/python/py-record-btrace.h
@@ -31,6 +31,9 @@ extern PyObject *recpy_bt_format (PyObject *self, void *closure);
 /* Implementation of record.goto (instruction) -> None.  */
 extern PyObject *recpy_bt_goto (PyObject *self, PyObject *value);
 
+/* Implementation of BtraceRecord.clear (self) -> None.  */
+extern PyObject *recpy_bt_clear (PyObject *self, PyObject *args);
+
 /* Implementation of record.instruction_history [list].  */
 extern PyObject *recpy_bt_instruction_history (PyObject *self, void *closure);
 
diff --git a/gdb/python/py-record.c b/gdb/python/py-record.c
index 47bbd290144..0aef0e0ae1b 100644
--- a/gdb/python/py-record.c
+++ b/gdb/python/py-record.c
@@ -127,6 +127,19 @@ recpy_goto (PyObject *self, PyObject *value)
   return PyErr_Format (PyExc_NotImplementedError, _("Not implemented."));
 }
 
+/* Implementation of record.clear () -> None.  */
+
+static PyObject *
+recpy_clear (PyObject *self, PyObject *value)
+{
+  const recpy_record_object * const obj = (recpy_record_object *) self;
+
+  if (obj->method == RECORD_METHOD_BTRACE)
+    return recpy_bt_clear (self, value);
+
+  return PyErr_Format (PyExc_NotImplementedError, _("Not implemented."));
+}
+
 /* Implementation of record.replay_position [instruction]  */
 
 static PyObject *
@@ -538,6 +551,9 @@ static PyMethodDef recpy_record_methods[] = {
   { "goto", recpy_goto, METH_VARARGS,
     "goto (instruction|function_call) -> None.\n\
 Rewind to given location."},
+  { "clear", recpy_clear, METH_VARARGS,
+    "clear () -> None.\n\
+Clears the trace."},
   { NULL }
 };
 
diff --git a/gdb/testsuite/gdb.python/py-record-btrace.exp b/gdb/testsuite/gdb.python/py-record-btrace.exp
index e9fdd06154e..82d887dbd18 100644
--- a/gdb/testsuite/gdb.python/py-record-btrace.exp
+++ b/gdb/testsuite/gdb.python/py-record-btrace.exp
@@ -88,7 +88,11 @@ with_test_prefix "instruction " {
     gdb_test "python print(repr(i.data))" "<memory at $hex>"
     gdb_test "python print(i.decoded)" ".*"
     gdb_test "python print(i.size)" "$decimal"
-    gdb_test "python print(i.is_speculative)" "False"
+    gdb_test "python print(i.is_speculative)" "False"    
+    gdb_test_no_output "python r.clear()"
+    gdb_test "python insn = r.instruction_history"
+    gdb_test_no_output "python i = insn\[0\]"
+    gdb_test "python print(i.size)" "$decimal"
 }
 
 with_test_prefix "function call" {
-- 
2.34.1

Intel Deutschland GmbH
Registered Address: Am Campeon 10, 85579 Neubiberg, Germany
Tel: +49 89 99 8853-0, www.intel.de <http://www.intel.de>
Managing Directors: Christin Eisenschmid, Sharon Heck, Tiffany Doon Silva  
Chairperson of the Supervisory Board: Nicole Lau
Registered Office: Munich
Commercial Register: Amtsgericht Muenchen HRB 186928

[PATCH v4 07/10] btrace, gdbserver: Add ptwrite to btrace_config_pt.

[Felix Willgerodt]

This enables gdb and gdbserver to communicate about ptwrite support.  If
ptwrite support would be enabled unconditionally, GDBs with older libipt
versions would break.
---
 gdb/btrace.c                 |  7 ++++++-
 gdb/doc/gdb.texinfo          | 21 +++++++++++++++++++++
 gdb/features/btrace-conf.dtd |  1 +
 gdb/remote.c                 | 30 ++++++++++++++++++++++++++++++
 gdbserver/linux-low.cc       |  1 +
 gdbserver/server.cc          | 15 +++++++++++++++
 gdbsupport/btrace-common.h   |  6 ++++++
 7 files changed, 80 insertions(+), 1 deletion(-)

diff --git a/gdb/btrace.c b/gdb/btrace.c
index 3305ebfb58f..0f5e73f35c4 100644
--- a/gdb/btrace.c
+++ b/gdb/btrace.c
@@ -2273,7 +2273,7 @@ parse_xml_btrace_conf_pt (struct gdb_xml_parser *parser,
 			  std::vector<gdb_xml_value> &attributes)
 {
   struct btrace_config *conf;
-  struct gdb_xml_value *size;
+  struct gdb_xml_value *size, *ptwrite;
 
   conf = (struct btrace_config *) user_data;
   conf->format = BTRACE_FORMAT_PT;
@@ -2282,10 +2282,15 @@ parse_xml_btrace_conf_pt (struct gdb_xml_parser *parser,
   size = xml_find_attribute (attributes, "size");
   if (size != NULL)
     conf->pt.size = (unsigned int) *(ULONGEST *) size->value.get ();
+
+  ptwrite = xml_find_attribute (attributes, "ptwrite");
+  if (ptwrite != nullptr)
+    conf->pt.ptwrite = (bool) *(ULONGEST *) ptwrite->value.get ();
 }
 
 static const struct gdb_xml_attribute btrace_conf_pt_attributes[] = {
   { "size", GDB_XML_AF_OPTIONAL, gdb_xml_parse_attr_ulongest, NULL },
+  { "ptwrite", GDB_XML_AF_OPTIONAL, gdb_xml_parse_attr_ulongest, nullptr },
   { NULL, GDB_XML_AF_NONE, NULL, NULL }
 };
 
diff --git a/gdb/doc/gdb.texinfo b/gdb/doc/gdb.texinfo
index fa3c8cb1cf3..7a35f8f526b 100644
--- a/gdb/doc/gdb.texinfo
+++ b/gdb/doc/gdb.texinfo
@@ -42580,6 +42580,11 @@ These are the currently defined stub features and their properties:
 @tab @samp{-}
 @tab Yes
 
+@item @samp{Qbtrace-conf:pt:ptwrite}
+@tab Yes
+@tab @samp{-}
+@tab Yes
+
 @item @samp{QNonStop}
 @tab No
 @tab @samp{-}
@@ -42891,6 +42896,9 @@ The remote stub understands the @samp{Qbtrace-conf:bts:size} packet.
 @item Qbtrace-conf:pt:size
 The remote stub understands the @samp{Qbtrace-conf:pt:size} packet.
 
+@item Qbtrace-conf:pt:ptwrite
+The remote stub understands the @samp{Qbtrace-conf:pt:ptwrite} packet.
+
 @item swbreak
 The remote stub reports the @samp{swbreak} stop reason for memory
 breakpoints.
@@ -43392,6 +43400,18 @@ The ring buffer size has been set.
 A badly formed request or an error was encountered.
 @end table
 
+@item Qbtrace-conf:pt:ptwrite=@var{value}
+Control recording of ptwrite packets.  This was added for backwards-
+compatibility.
+
+Reply:
+@table @samp
+@item OK
+The ptwrite config parameter has been set.
+@item E.errtext
+A badly formed request or an error was encountered.
+@end table
+
 @end table
 
 @node Architecture-Specific Protocol Details
@@ -46034,6 +46054,7 @@ The formal DTD for the branch trace configuration format is given below:
 
 <!ELEMENT pt	EMPTY>
 <!ATTLIST pt	size	CDATA	#IMPLIED>
+<!ATTLIST pt	ptwrite	CDATA	#IMPLIED>
 @end smallexample
 
 @include agentexpr.texi
diff --git a/gdb/features/btrace-conf.dtd b/gdb/features/btrace-conf.dtd
index c71b11f2087..e8cf32adf02 100644
--- a/gdb/features/btrace-conf.dtd
+++ b/gdb/features/btrace-conf.dtd
@@ -12,3 +12,4 @@
 
 <!ELEMENT pt	EMPTY>
 <!ATTLIST pt	size	CDATA	#IMPLIED>
+<!ATTLIST pt	ptwrite	CDATA	#IMPLIED>
diff --git a/gdb/remote.c b/gdb/remote.c
index b8df3326849..aa249f23580 100644
--- a/gdb/remote.c
+++ b/gdb/remote.c
@@ -2204,6 +2204,9 @@ enum {
   /* Support for the Qbtrace-conf:pt:size packet.  */
   PACKET_Qbtrace_conf_pt_size,
 
+  /* Support for the Qbtrace-conf:pt:ptwrite packet.  */
+  PACKET_Qbtrace_conf_pt_ptwrite,
+
   /* Support for exec events.  */
   PACKET_exec_event_feature,
 
@@ -5422,6 +5425,8 @@ static const struct protocol_feature remote_protocol_features[] = {
     PACKET_exec_event_feature },
   { "Qbtrace-conf:pt:size", PACKET_DISABLE, remote_supported_packet,
     PACKET_Qbtrace_conf_pt_size },
+  { "Qbtrace-conf:pt:ptwrite", PACKET_DISABLE, remote_supported_packet,
+    PACKET_Qbtrace_conf_pt_ptwrite },
   { "vContSupported", PACKET_DISABLE, remote_supported_packet, PACKET_vContSupported },
   { "QThreadEvents", PACKET_DISABLE, remote_supported_packet, PACKET_QThreadEvents },
   { "no-resumed", PACKET_DISABLE, remote_supported_packet, PACKET_no_resumed },
@@ -14106,6 +14111,28 @@ remote_target::btrace_sync_conf (const btrace_config *conf)
 
       rs->btrace_config.pt.size = conf->pt.size;
     }
+
+  packet = &remote_protocol_packets[PACKET_Qbtrace_conf_pt_ptwrite];
+  if (packet_config_support (packet) == PACKET_ENABLE
+      && conf->pt.ptwrite != rs->btrace_config.pt.ptwrite)
+    {
+      pos = buf;
+      pos += xsnprintf (pos, endbuf - pos, "%s=%d", packet->name,
+                        conf->pt.ptwrite);
+
+      putpkt (buf);
+      getpkt (&rs->buf, 0);
+
+      if (packet_ok (buf, packet) == PACKET_ERROR)
+	{
+	  if (buf[0] == 'E' && buf[1] == '.')
+	    error (_("Failed to sync ptwrite config: %s"), buf + 2);
+	  else
+	    error (_("Failed to sync ptwrite config."));
+	}
+
+      rs->btrace_config.pt.ptwrite = conf->pt.ptwrite;
+    }
 }
 
 /* Read TP's btrace configuration from the target and store it into CONF.  */
@@ -15328,6 +15355,9 @@ Show the maximum size of the address (in bits) in a memory packet."), NULL,
   add_packet_config_cmd (&remote_protocol_packets[PACKET_Qbtrace_conf_pt_size],
        "Qbtrace-conf:pt:size", "btrace-conf-pt-size", 0);
 
+  add_packet_config_cmd (&remote_protocol_packets[PACKET_Qbtrace_conf_pt_ptwrite],
+       "Qbtrace-conf:pt:ptwrite", "btrace-conf-pt-ptwrite", 0);
+
   add_packet_config_cmd (&remote_protocol_packets[PACKET_vContSupported],
 			 "vContSupported", "verbose-resume-supported", 0);
 
diff --git a/gdbserver/linux-low.cc b/gdbserver/linux-low.cc
index 8b8614f6ed4..35cd76d9fe3 100644
--- a/gdbserver/linux-low.cc
+++ b/gdbserver/linux-low.cc
@@ -6798,6 +6798,7 @@ linux_process_target::read_btrace_conf (const btrace_target_info *tinfo,
 	case BTRACE_FORMAT_PT:
 	  buffer_xml_printf (buffer, "<pt");
 	  buffer_xml_printf (buffer, " size=\"0x%x\"", conf->pt.size);
+	  buffer_xml_printf (buffer, " ptwrite=\"%d\"", conf->pt.ptwrite);
 	  buffer_xml_printf (buffer, "/>\n");
 	  break;
 	}
diff --git a/gdbserver/server.cc b/gdbserver/server.cc
index f9c02a9c6da..d46e9633cc7 100644
--- a/gdbserver/server.cc
+++ b/gdbserver/server.cc
@@ -542,6 +542,20 @@ handle_btrace_conf_general_set (char *own_buf)
 
       current_btrace_conf.pt.size = (unsigned int) size;
     }
+  else if (strncmp (op, "pt:ptwrite=", strlen ("pt:ptwrite=")) == 0)
+    {
+      char *endp = nullptr;
+
+      errno = 0;
+      int ptwrite = strtoul (op + strlen ("pt:ptwrite="), &endp, 16);
+      if (endp == nullptr || *endp != 0 || errno != 0 || ptwrite > 1)
+	{
+	  strcpy (own_buf, "E.Bad ptwrite value.");
+	  return -1;
+	}
+
+      current_btrace_conf.pt.ptwrite = (bool) ptwrite;
+    }
   else
     {
       strcpy (own_buf, "E.Bad Qbtrace configuration option.");
@@ -2162,6 +2176,7 @@ supported_btrace_packets (char *buf)
   strcat (buf, ";Qbtrace-conf:bts:size+");
   strcat (buf, ";Qbtrace:pt+");
   strcat (buf, ";Qbtrace-conf:pt:size+");
+  strcat (buf, ";Qbtrace-conf:pt:ptwrite+");
   strcat (buf, ";Qbtrace:off+");
   strcat (buf, ";qXfer:btrace:read+");
   strcat (buf, ";qXfer:btrace-conf:read+");
diff --git a/gdbsupport/btrace-common.h b/gdbsupport/btrace-common.h
index 3c55ae92185..96d11d77d33 100644
--- a/gdbsupport/btrace-common.h
+++ b/gdbsupport/btrace-common.h
@@ -117,6 +117,12 @@ struct btrace_config_pt
      This is unsigned int and not size_t since it is registered as
      control variable for "set record btrace pt buffer-size".  */
   unsigned int size;
+
+  /* Configuration bit for ptwrite packets.
+
+     If this is set, gdb will try to enable ptwrite packets if the OS
+     supports this.  */
+  bool ptwrite;
 };
 
 /* A branch tracing configuration.
-- 
2.34.1

Intel Deutschland GmbH
Registered Address: Am Campeon 10, 85579 Neubiberg, Germany
Tel: +49 89 99 8853-0, www.intel.de <http://www.intel.de>
Managing Directors: Christin Eisenschmid, Sharon Heck, Tiffany Doon Silva  
Chairperson of the Supervisory Board: Nicole Lau
Registered Office: Munich
Commercial Register: Amtsgericht Muenchen HRB 186928

[PATCH v4 08/10] btrace, linux: Enable ptwrite packets.

[Felix Willgerodt]

Enable ptwrite in the PT config, if it is supported by the kernel.
---
 gdb/nat/linux-btrace.c | 29 +++++++++++++++++++++++++++++
 gdb/record-btrace.c    |  5 +++++
 2 files changed, 34 insertions(+)

diff --git a/gdb/nat/linux-btrace.c b/gdb/nat/linux-btrace.c
index b0d6dcd7cf1..53f1a468bcc 100644
--- a/gdb/nat/linux-btrace.c
+++ b/gdb/nat/linux-btrace.c
@@ -415,6 +415,29 @@ cpu_supports_bts (void)
     }
 }
 
+/* Check whether the linux target supports Intel Processor Trace PTWRITE.  */
+
+static bool
+linux_supports_ptwrite ()
+{
+  static const char filename[]
+      = "/sys/bus/event_source/devices/intel_pt/caps/ptwrite";
+  gdb_file_up file = gdb_fopen_cloexec (filename, "r");
+
+  if (file.get () == nullptr)
+    return false;
+
+  int status, found = fscanf (file.get (), "%d", &status);
+
+  if (found != 1)
+    {
+      warning (_("Failed to determine ptwrite support from %s."), filename);
+      return false;
+    }
+
+  return status == 1;
+}
+
 /* The perf_event_open syscall failed.  Try to print a helpful error
    message.  */
 
@@ -624,6 +647,12 @@ linux_enable_pt (ptid_t ptid, const struct btrace_config_pt *conf)
   pt->attr.exclude_hv = 1;
   pt->attr.exclude_idle = 1;
 
+  if (conf->ptwrite && linux_supports_ptwrite ())
+    {
+      pt->attr.config |= 0x1000;
+      tinfo->conf.pt.ptwrite = conf->ptwrite;
+    }
+
   errno = 0;
   scoped_fd fd (syscall (SYS_perf_event_open, &pt->attr, pid, -1, -1, 0));
   if (fd.get () < 0)
diff --git a/gdb/record-btrace.c b/gdb/record-btrace.c
index 1bfb9c1d876..799a9ea96ee 100644
--- a/gdb/record-btrace.c
+++ b/gdb/record-btrace.c
@@ -3289,4 +3289,9 @@ to see the actual buffer size."), NULL, show_record_pt_buffer_size_value,
 
   record_btrace_conf.bts.size = 64 * 1024;
   record_btrace_conf.pt.size = 16 * 1024;
+#if (LIBIPT_VERSION >= 0x200)
+  record_btrace_conf.pt.ptwrite = true;
+#else
+  record_btrace_conf.pt.ptwrite = false;
+#endif
 }
-- 
2.34.1

Intel Deutschland GmbH
Registered Address: Am Campeon 10, 85579 Neubiberg, Germany
Tel: +49 89 99 8853-0, www.intel.de <http://www.intel.de>
Managing Directors: Christin Eisenschmid, Sharon Heck, Tiffany Doon Silva  
Chairperson of the Supervisory Board: Nicole Lau
Registered Office: Munich
Commercial Register: Amtsgericht Muenchen HRB 186928

[PATCH v4 09/10] btrace, python: Enable ptwrite listener registration.

[Felix Willgerodt]

With this patch a default ptwrite listener is registered upon start of GDB.
It prints the plain ptwrite payload as hex.  The default listener can be
overwritten by registering a custom listener in python or by registering
"None", for no output at all.  Registering a listener function creates per
thread copies to allow unique internal states per thread.
---
 gdb/btrace.c                   |   3 +
 gdb/btrace.h                   |  11 ++++
 gdb/data-directory/Makefile.in |   1 +
 gdb/extension-priv.h           |   5 ++
 gdb/extension.c                |  14 +++++
 gdb/extension.h                |   3 +
 gdb/guile/guile.c              |   1 +
 gdb/python/lib/gdb/ptwrite.py  |  86 ++++++++++++++++++++++++++
 gdb/python/py-record-btrace.c  | 109 +++++++++++++++++++++++++++++++++
 gdb/python/py-record-btrace.h  |   8 +++
 gdb/python/python-internal.h   |   3 +
 gdb/python/python.c            |   2 +
 12 files changed, 246 insertions(+)
 create mode 100644 gdb/python/lib/gdb/ptwrite.py

diff --git a/gdb/btrace.c b/gdb/btrace.c
index 0f5e73f35c4..fa26ddc2b4a 100644
--- a/gdb/btrace.c
+++ b/gdb/btrace.c
@@ -34,6 +34,7 @@
 #include "gdbsupport/rsp-low.h"
 #include "gdbcmd.h"
 #include "cli/cli-utils.h"
+#include "extension.h"
 #include "gdbarch.h"
 
 /* For maintenance commands.  */
@@ -1317,6 +1318,8 @@ ftrace_add_pt (struct btrace_thread_info *btinfo,
   uint64_t offset;
   int status;
 
+  apply_ext_lang_ptwrite_listener (btinfo);
+
   for (;;)
     {
       struct pt_insn insn;
diff --git a/gdb/btrace.h b/gdb/btrace.h
index 69ce2f3330d..8650a582a76 100644
--- a/gdb/btrace.h
+++ b/gdb/btrace.h
@@ -352,6 +352,17 @@ struct btrace_thread_info
      displaying or stepping through the execution history.  */
   std::vector<std::string> aux_data;
 
+  /* Function pointer to the ptwrite callback.  Returns the string returned
+     by the ptwrite listener function or nullptr if no string is supposed to
+     be printed.  */
+  gdb::unique_xmalloc_ptr<char> (*ptw_callback_fun) (
+						const uint64_t payload,
+						const uint64_t ip,
+						const void *ptw_listener);
+
+  /* PyObject pointer to the ptwrite listener function.  */
+  void *ptw_listener = nullptr;
+
   /* The function level offset.  When added to each function's LEVEL,
      this normalizes the function levels such that the smallest level
      becomes zero.  */
diff --git a/gdb/data-directory/Makefile.in b/gdb/data-directory/Makefile.in
index b606fc654b5..c8172dab558 100644
--- a/gdb/data-directory/Makefile.in
+++ b/gdb/data-directory/Makefile.in
@@ -74,6 +74,7 @@ PYTHON_FILE_LIST = \
 	gdb/frames.py \
 	gdb/printing.py \
 	gdb/prompt.py \
+	gdb/ptwrite.py \
 	gdb/styling.py \
 	gdb/types.py \
 	gdb/unwinder.py \
diff --git a/gdb/extension-priv.h b/gdb/extension-priv.h
index d9450b51231..2ca84c33671 100644
--- a/gdb/extension-priv.h
+++ b/gdb/extension-priv.h
@@ -183,6 +183,11 @@ struct extension_language_ops
      enum ext_lang_frame_args args_type,
      struct ui_out *out, int frame_low, int frame_high);
 
+  /* Used for registering the ptwrite listener to the current thread.  */
+  void (*apply_ptwrite_listener)
+    (const struct extension_language_defn *extlang,
+     struct btrace_thread_info *btinfo);
+
   /* Update values held by the extension language when OBJFILE is discarded.
      New global types must be created for every such value, which must then be
      updated to use the new types.
diff --git a/gdb/extension.c b/gdb/extension.c
index 8f39b86e952..9cc742d2743 100644
--- a/gdb/extension.c
+++ b/gdb/extension.c
@@ -550,6 +550,20 @@ apply_ext_lang_frame_filter (struct frame_info *frame,
   return EXT_LANG_BT_NO_FILTERS;
 }
 
+/* Used for registering the ptwrite listener to the current thread.  */
+
+void
+apply_ext_lang_ptwrite_listener (btrace_thread_info *btinfo)
+{
+  for (const struct extension_language_defn *extlang : extension_languages)
+    {
+      if (extlang->ops != nullptr
+	  && extlang->ops->apply_ptwrite_listener != nullptr)
+	extlang->ops->apply_ptwrite_listener (extlang, btinfo);
+
+    }
+}
+
 /* Update values held by the extension language when OBJFILE is discarded.
    New global types must be created for every such value, which must then be
    updated to use the new types.
diff --git a/gdb/extension.h b/gdb/extension.h
index 7eb89530c44..9d1c4838116 100644
--- a/gdb/extension.h
+++ b/gdb/extension.h
@@ -295,6 +295,9 @@ extern enum ext_lang_bt_status apply_ext_lang_frame_filter
    enum ext_lang_frame_args args_type,
    struct ui_out *out, int frame_low, int frame_high);
 
+extern void apply_ext_lang_ptwrite_listener
+  (struct btrace_thread_info *btinfo);
+
 extern void preserve_ext_lang_values (struct objfile *, htab_t copied_types);
 
 extern const struct extension_language_defn *get_breakpoint_cond_ext_lang
diff --git a/gdb/guile/guile.c b/gdb/guile/guile.c
index c7be48fb739..1e90eb2c11d 100644
--- a/gdb/guile/guile.c
+++ b/gdb/guile/guile.c
@@ -124,6 +124,7 @@ static const struct extension_language_ops guile_extension_ops =
   gdbscm_apply_val_pretty_printer,
 
   NULL, /* gdbscm_apply_frame_filter, */
+  NULL, /* gdbscm_load_ptwrite_listener, */
 
   gdbscm_preserve_values,
 
diff --git a/gdb/python/lib/gdb/ptwrite.py b/gdb/python/lib/gdb/ptwrite.py
new file mode 100644
index 00000000000..13caeacf5ee
--- /dev/null
+++ b/gdb/python/lib/gdb/ptwrite.py
@@ -0,0 +1,86 @@
+# Ptwrite utilities.
+# Copyright (C) 2022 Free Software Foundation, Inc.
+
+# 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/>.
+
+"""Utilities for working with ptwrite listeners."""
+
+import gdb
+from copy import deepcopy
+
+
+def default_listener(payload, ip):
+    """Default listener that is active upon starting GDB."""
+    return "{:x}".format(payload)
+
+# This dict contains the per thread copies of the listener function and the
+# global template listener, from which the copies are created.
+_ptwrite_listener = {"global" : default_listener}
+
+
+def _update_listener_dict(thread_list):
+    """Helper function to update the listener dict.
+
+    Discards listener copies of threads that already exited and registers
+    copies of the listener for new threads."""
+    # thread_list[x].ptid returns the tuple (pid, lwp, tid)
+    lwp_list = [i.ptid[1] for i in thread_list]
+
+    # clean-up old listeners
+    for key in _ptwrite_listener.keys():
+      if key not in lwp_list and key != "global":
+        _ptwrite_listener.pop(key)
+
+    # Register listener for new threads
+    for key in lwp_list:
+        if key not in _ptwrite_listener.keys():
+            _ptwrite_listener[key] = deepcopy(_ptwrite_listener["global"])
+
+
+def _clear_traces(thread_list):
+    """Helper function to clear the trace of all threads in THREAD_LIST."""
+    current_thread = gdb.selected_thread()
+
+    recording = gdb.current_recording()
+
+    if (recording is not None):
+        for thread in thread_list:
+            thread.switch()
+            recording.clear()
+
+        current_thread.switch()
+
+
+def register_listener(listener):
+    """Register the ptwrite listener function."""
+    if listener is not None and not callable(listener):
+        raise TypeError("Listener must be callable!")
+
+    # Clear the traces of all threads to force re-decoding with
+    # the new listener.
+    thread_list = gdb.Inferior.threads(gdb.selected_inferior())
+    _clear_traces(thread_list)
+
+    _ptwrite_listener.clear()
+    _ptwrite_listener["global"] = listener
+
+    _update_listener_dict(thread_list)
+
+
+def get_listener():
+    """Returns the listeners of the current thread."""
+    thread_list = gdb.Inferior.threads(gdb.selected_inferior())
+    _update_listener_dict(thread_list)
+
+    return _ptwrite_listener[gdb.selected_thread().ptid[1]]
diff --git a/gdb/python/py-record-btrace.c b/gdb/python/py-record-btrace.c
index 8b3ae8c3fab..e106abb7b52 100644
--- a/gdb/python/py-record-btrace.c
+++ b/gdb/python/py-record-btrace.c
@@ -762,6 +762,115 @@ recpy_bt_function_call_history (PyObject *self, void *closure)
   return btpy_list_new (tinfo, first, last, 1, &recpy_func_type);
 }
 
+/* Helper function that calls the ptwrite listener PTW_LISTENER with
+   PAYLOAD and IP as arguments.  Returns a pointer to the string that will
+   be printed or nullptr if nothing should be printed.  IP can be nullptr,
+   PAYLOAD must point to a valid integer.  */
+gdb::unique_xmalloc_ptr<char>
+recpy_call_listener (const uint64_t payload, const uint64_t ip,
+		     const void *ptw_listener)
+{
+  if ((PyObject *) ptw_listener == Py_None)
+    return nullptr;
+  else if ((PyObject *) ptw_listener == nullptr)
+    error (_("No valid ptwrite listener."));
+
+  /* As Python is started as a seperate thread, we need to
+     acquire the GIL to safely call the listener function.  */
+  PyGILState_STATE gstate = PyGILState_Ensure ();
+
+  PyObject *py_payload = PyLong_FromUnsignedLongLong (payload);
+  PyObject *py_ip;
+
+  if (ip == 0)
+    {
+      py_ip = Py_None;
+      Py_INCREF (Py_None);
+    }
+  else
+    py_ip = PyLong_FromUnsignedLongLong (ip);
+
+  PyObject *py_result = PyObject_CallFunctionObjArgs ((PyObject *) ptw_listener,
+						      py_payload, py_ip,
+						      nullptr);
+
+  if (PyErr_Occurred ())
+    {
+      gdbpy_print_stack ();
+      Py_DECREF (py_ip);
+      Py_DECREF (py_payload);
+      PyGILState_Release (gstate);
+      error (_("Error while executing Python code."));
+    }
+
+  Py_DECREF (py_ip);
+  Py_DECREF (py_payload);
+
+  if (py_result == Py_None)
+    {
+      Py_DECREF (py_result);
+      PyGILState_Release (gstate);
+      return nullptr;
+    }
+
+  gdb::unique_xmalloc_ptr<char> resultstring = gdbpy_obj_to_string (py_result);
+
+  if (PyErr_Occurred ())
+    {
+      gdbpy_print_stack ();
+      Py_DECREF (py_result);
+      PyGILState_Release (gstate);
+      error (_("Error while executing Python code."));
+    }
+
+  Py_DECREF (py_result);
+  PyGILState_Release (gstate);
+
+  return resultstring;
+}
+
+/* Helper function returning the current ptwrite listener.  Returns nullptr
+   in case of errors.  */
+
+PyObject *
+get_ptwrite_listener ()
+{
+  PyObject *module = PyImport_ImportModule ("gdb.ptwrite");
+
+  if (PyErr_Occurred ())
+  {
+    gdbpy_print_stack ();
+    return nullptr;
+  }
+
+  PyObject *ptw_listener = PyObject_CallMethod (module,
+						"get_listener",
+						nullptr);
+
+  Py_DECREF (module);
+
+  if (PyErr_Occurred ())
+    gdbpy_print_stack ();
+
+  return ptw_listener;
+}
+
+/* Used for registering the default ptwrite listener to the current thread.  A
+   pointer to this function is stored in the python extension interface.  */
+
+void
+gdbpy_load_ptwrite_listener (const struct extension_language_defn *extlang,
+			     struct btrace_thread_info *btinfo)
+{
+  if (!gdb_python_initialized || btinfo == nullptr)
+    return;
+
+  gdbpy_enter enter_py;
+
+  btinfo->ptw_callback_fun = &recpy_call_listener;
+  btinfo->ptw_listener = get_ptwrite_listener ();
+}
+
 /* Implementation of BtraceRecord.goto (self, BtraceInstruction) -> None.  */
 
 PyObject *
diff --git a/gdb/python/py-record-btrace.h b/gdb/python/py-record-btrace.h
index b25b121d255..fea0f675947 100644
--- a/gdb/python/py-record-btrace.h
+++ b/gdb/python/py-record-btrace.h
@@ -91,4 +91,12 @@ extern PyObject *recpy_bt_func_prev (PyObject *self, void *closure);
 /* Implementation of RecordFunctionSegment.next [RecordFunctionSegment].  */
 extern PyObject *recpy_bt_func_next (PyObject *self, void *closure);
 
+/* Helper function returning the current ptwrite listener.  */
+extern PyObject *get_ptwrite_listener ();
+
+/* Callback function for the ptwrite listener.  */
+extern gdb::unique_xmalloc_ptr<char>
+recpy_call_listener (const uint64_t payload, const uint64_t ip,
+                     const void *ptw_listener);
+
 #endif /* PYTHON_PY_RECORD_BTRACE_H */
diff --git a/gdb/python/python-internal.h b/gdb/python/python-internal.h
index d947b96033b..b48412fff38 100644
--- a/gdb/python/python-internal.h
+++ b/gdb/python/python-internal.h
@@ -359,6 +359,9 @@ extern enum ext_lang_rc gdbpy_apply_val_pretty_printer
    struct ui_file *stream, int recurse,
    const struct value_print_options *options,
    const struct language_defn *language);
+extern void gdbpy_load_ptwrite_listener
+  (const struct extension_language_defn *extlang,
+   struct btrace_thread_info *btinfo);
 extern enum ext_lang_bt_status gdbpy_apply_frame_filter
   (const struct extension_language_defn *,
    struct frame_info *frame, frame_filter_flags flags,
diff --git a/gdb/python/python.c b/gdb/python/python.c
index 11aaa7ae778..c9d61e473f8 100644
--- a/gdb/python/python.c
+++ b/gdb/python/python.c
@@ -151,6 +151,8 @@ static const struct extension_language_ops python_extension_ops =
 
   gdbpy_apply_frame_filter,
 
+  gdbpy_load_ptwrite_listener,
+
   gdbpy_preserve_values,
 
   gdbpy_breakpoint_has_cond,
-- 
2.34.1

Intel Deutschland GmbH
Registered Address: Am Campeon 10, 85579 Neubiberg, Germany
Tel: +49 89 99 8853-0, www.intel.de <http://www.intel.de>
Managing Directors: Christin Eisenschmid, Sharon Heck, Tiffany Doon Silva  
Chairperson of the Supervisory Board: Nicole Lau
Registered Office: Munich
Commercial Register: Amtsgericht Muenchen HRB 186928

[PATCH v4 10/10] btrace: Extend ptwrite event decoding.

[Felix Willgerodt]

Call the ptwrite listener function whenever a ptwrite event is decoded.
The returned string is written to the aux_data string table and a
corresponding auxiliary instruction is appended to the function segment.
---
 gdb/NEWS                                  |   6 +
 gdb/btrace.c                              |  53 +++
 gdb/config.in                             |   3 +
 gdb/configure                             |  11 +
 gdb/doc/python.texi                       | 149 +++++++++
 gdb/testsuite/gdb.btrace/i386-ptwrite.S   | 379 ++++++++++++++++++++++
 gdb/testsuite/gdb.btrace/ptwrite.c        |  37 +++
 gdb/testsuite/gdb.btrace/ptwrite.exp      | 219 +++++++++++++
 gdb/testsuite/gdb.btrace/x86_64-ptwrite.S | 374 +++++++++++++++++++++
 gdb/testsuite/lib/gdb.exp                 | 153 +++++++++
 gdbsupport/common.m4                      |   2 +
 gdbsupport/config.in                      |   3 +
 gdbsupport/configure                      |  11 +
 13 files changed, 1400 insertions(+)
 create mode 100644 gdb/testsuite/gdb.btrace/i386-ptwrite.S
 create mode 100644 gdb/testsuite/gdb.btrace/ptwrite.c
 create mode 100644 gdb/testsuite/gdb.btrace/ptwrite.exp
 create mode 100644 gdb/testsuite/gdb.btrace/x86_64-ptwrite.S

diff --git a/gdb/NEWS b/gdb/NEWS
index a72fee81550..cf807d6209e 100644
--- a/gdb/NEWS
+++ b/gdb/NEWS
@@ -331,6 +331,12 @@ GNU/Linux/OpenRISC		or1k*-*-linux*
 
 *** Changes in GDB 11
 
+* GDB now supports printing of ptwrite payloads from the Intel Processor
+  Trace during 'record instruction-history', 'record function-call-history',
+  all stepping commands and in  Python.  Printing is customizable via a
+  ptwrite listener function in  Python.  By default, the raw ptwrite
+  payload is printed for each ptwrite that is encountered.
+
 * The 'set disassembler-options' command now supports specifying options
   for the ARC target.
 
diff --git a/gdb/btrace.c b/gdb/btrace.c
index fa26ddc2b4a..ce45a8897e7 100644
--- a/gdb/btrace.c
+++ b/gdb/btrace.c
@@ -1253,6 +1253,53 @@ handle_pt_insn_events (struct btrace_thread_info *btinfo,
 		   bfun->insn_offset - 1, offset);
 
 	  break;
+#if defined (HAVE_STRUCT_PT_EVENT_VARIANT_PTWRITE)
+	case ptev_ptwrite:
+	  {
+	    uint64_t ip = 0;
+	    gdb::unique_xmalloc_ptr<char> ptw_string = nullptr;
+	    btrace_insn_flags flags = 0;
+
+	    /* Lookup the ip if available.  */
+	    if (event.ip_suppressed == 0)
+	      ip = event.variant.ptwrite.ip;
+
+	    if (btinfo->ptw_callback_fun != nullptr)
+	      ptw_string
+		= btinfo->ptw_callback_fun (event.variant.ptwrite.payload,
+					    ip, btinfo->ptw_listener);
+
+	    if (ptw_string == nullptr)
+	      break;
+
+	    btinfo->aux_data.emplace_back (ptw_string.get ());
+
+	    if (!btinfo->functions.empty ()
+		&& !btinfo->functions.back ().insn.empty ())
+	      flags = btinfo->functions.back ().insn.back ().flags;
+
+	    /* Update insn list with ptw payload insn.  */
+	    struct btrace_insn ptw_insn = { 0 };
+	    ptw_insn.aux_data_index = btinfo->aux_data.size () - 1;
+	    ptw_insn.flags = flags;
+	    ptw_insn.iclass = BTRACE_INSN_AUX;
+
+	    if (ip != 0)
+	      bfun = ftrace_update_function (btinfo, ip);
+	    else
+	      {
+		if (btinfo->functions.empty ())
+		  bfun = ftrace_new_function (btinfo, NULL, NULL);
+		else
+		  bfun = &btinfo->functions.back ();
+	      }
+
+	    bfun->flags |= BFUN_AUX_DECODED;
+	    ftrace_update_insns (bfun, ptw_insn);
+
+	    break;
+	  }
+#endif /* defined (HAVE_STRUCT_PT_EVENT_VARIANT_PTWRITE) */
 	}
     }
 #endif /* defined (HAVE_PT_INSN_EVENT) */
@@ -2979,6 +3026,12 @@ pt_print_packet (const struct pt_packet *packet)
     case ppt_mnt:
       gdb_printf (("mnt %" PRIx64 ""), packet->payload.mnt.payload);
       break;
+
+#if defined (HAVE_STRUCT_PT_EVENT_VARIANT_PTWRITE)
+    case ppt_ptw:
+      gdb_printf (("ptw %" PRIx64 ""), packet->payload.ptw.payload);
+      break;
+#endif /* defined (HAVE_STRUCT_PT_EVENT_VARIANT_PTWRITE) */
     }
 }
 
diff --git a/gdb/config.in b/gdb/config.in
index a4975c68aad..d572c51ec79 100644
--- a/gdb/config.in
+++ b/gdb/config.in
@@ -460,6 +460,9 @@
 /* Define to 1 if `pl_tdname' is a member of `struct ptrace_lwpinfo'. */
 #undef HAVE_STRUCT_PTRACE_LWPINFO_PL_TDNAME
 
+/* Define to 1 if `variant.ptwrite' is a member of `struct pt_event'. */
+#undef HAVE_STRUCT_PT_EVENT_VARIANT_PTWRITE
+
 /* Define to 1 if `enabled' is a member of `struct pt_insn'. */
 #undef HAVE_STRUCT_PT_INSN_ENABLED
 
diff --git a/gdb/configure b/gdb/configure
index 1008cbef28b..e7bd28f173d 100755
--- a/gdb/configure
+++ b/gdb/configure
@@ -15327,6 +15327,17 @@ cat >>confdefs.h <<_ACEOF
 _ACEOF
 
 
+fi
+
+      ac_fn_c_check_member "$LINENO" "struct pt_event" "variant.ptwrite" "ac_cv_member_struct_pt_event_variant_ptwrite" "#include <intel-pt.h>
+"
+if test "x$ac_cv_member_struct_pt_event_variant_ptwrite" = xyes; then :
+
+cat >>confdefs.h <<_ACEOF
+#define HAVE_STRUCT_PT_EVENT_VARIANT_PTWRITE 1
+_ACEOF
+
+
 fi
 
       LIBS=$save_LIBS
diff --git a/gdb/doc/python.texi b/gdb/doc/python.texi
index 707aa5c3ee3..88fc1f93a5b 100644
--- a/gdb/doc/python.texi
+++ b/gdb/doc/python.texi
@@ -6649,6 +6649,7 @@ registering objfile-specific pretty-printers and frame-filters.
 * gdb.printing::       Building and registering pretty-printers.
 * gdb.types::          Utilities for working with types.
 * gdb.prompt::         Utilities for prompt value substitution.
+* gdb.ptwrite::        Utilities for ptwrite listener registration.
 @end menu
 
 @node gdb.printing
@@ -6839,3 +6840,151 @@ substitute_prompt ("frame: \f, args: \p@{print frame-arguments@}")
 "frame: main, args: scalars"
 @end smallexample
 @end table
+
+@node gdb.ptwrite
+@subsubsection gdb.ptwrite
+@cindex gdb.ptwrite
+
+This module provides additional functionality for recording programs that
+make use of the @code{PTWRITE} instruction.  @code{PTWRITE} is a x86
+instruction that allows to write values into the Intel Processor Trace
+(@pxref{Process Record and Replay}).
+The @value{NGCC} built-in functions for it are:
+@smallexample
+void __builtin_ia32_ptwrite32 (unsigned);
+void __builtin_ia32_ptwrite64 (unsigned long long);
+@end smallexample
+
+If an inferior uses the instruction, @value{GDBN} by default inserts the
+raw payload value as auxiliary information into the execution history.
+Auxiliary information is by default printed during
+@code{record instruction-history}, @code{record function-call-history},
+and all stepping commands and is accessible in Python as a
+@code{RecordAuxiliary} object.
+
+@exdent Sample program:
+@smallexample
+@group
+void
+ptwrite64 (unsigned long long value)
+@{
+  __builtin_ia32_ptwrite64 (value);
+@}
+@end group
+
+@group
+int
+main (void)
+@{
+  ptwrite64 (0x42);
+  return 0; /* break here.  */
+@}
+@end group
+@end smallexample
+
+
+@exdent @value{GDBN} output after recording the sample program in pt format:
+@smallexample
+@group
+(gdb) record instruction-history 12,14
+12         0x000000000040074c <ptwrite64+16>:	ptwrite %rbx
+13         [42]
+14         0x0000000000400751 <ptwrite64+21>:	mov    -0x8(%rbp),%rbx
+(gdb) record function-call-history
+1       main
+2       ptwrite64
+                [42]
+3       main
+@end group
+@end smallexample
+
+The @code{gdb.ptwrite} module allows customizing the default output of ptwrite
+auxiliary information.  A custom Python function can be registered via
+@code{gdb.ptwrite.register_listener} as the ptwrite listener function.
+This function will be called with the ptwrite payload and PC as arguments
+during trace decoding.
+
+@findex gdb.ptwrite.register_listener
+@defun register_listener (@var{listener})
+Used to register the ptwrite listener.  The listener can be any callable
+object that accepts two arguments.  It can return a string, which will be
+printed by @value{GDBN} during the aforementioned commands, or @code{None},
+resulting in no output.  @code{None} can also be registered to deactivate
+printing.
+@end defun
+
+@findex gdb.ptwrite.get_listener
+@defun get_listener ()
+Returns the currently active ptwrite listener function.
+@end defun
+
+@findex gdb.ptwrite.default_listener
+@defun default_listener (@var{payload}, @var{ip})
+The listener function active by default.
+@end defun
+
+@value{GDBN} creates a new copy of the listener function for each thread to
+allow for independent internal states.  There is no support for registering
+different listeners for different threads.  The listener can however
+distinguish between multiple threads with the help of
+@code{gdb.selected_thread().global_num} (@pxref{Threads In Python}) or
+similar.  For example:
+
+@smallexample
+@group
+(gdb) python-interactive
+>>> class my_listener(object):
+...    def __init__(self):
+...        self.var = 0
+...    def __call__(self, payload, ip):
+...        if gdb.selected_thread().global_num == 1:
+...            self.var += 1
+...            return "counter: @{@}, ip: @{:#x@}".format(self.var, ip)
+...        else:
+...            return None
+...
+>>> import gdb.ptwrite
+>>> gdb.ptwrite.register_listener(my_listener())
+>>>
+@end group
+
+@group
+(gdb) record function-call-history 59,64
+59      pthread_create@@GLIBC_2.2.5
+60      job()
+61      task(void*)
+62      ptwrite64(unsigned long)
+                [counter: 1, ip: 0x401156]
+63      task(void*)
+64      ptwrite32(unsigned int)
+                [counter: 2, ip: 0x40116c]
+@end group
+
+@group
+(gdb) info threads 
+* 1    Thread 0x7ffff7fd8740 (LWP 25796) "ptwrite_threads" task (arg=0x0)
+    at bin/ptwrite/ptwrite_threads.c:45
+  2    Thread 0x7ffff6eb8700 (LWP 25797) "ptwrite_threads" task (arg=0x0)
+    at bin/ptwrite/ptwrite_threads.c:45
+@end group
+
+@group
+(gdb) thread 2
+[Switching to thread 2 (Thread 0x7ffff6eb8700 (LWP 25797))]
+#0  task (arg=0x0) at ptwrite_threads.c:45
+45        return NULL;
+@end group
+
+@group
+(gdb) record function-call-history 10,14
+10    start_thread
+11    task(void*)
+12    ptwrite64(unsigned long)
+13    task(void*)
+14    ptwrite32(unsigned int)
+@end group
+@end smallexample
+
+This @value{GDBN} feature is dependent on hardware and operating system
+support and requires the Intel Processor Trace decoder library in version
+2.0.0 or newer.
diff --git a/gdb/testsuite/gdb.btrace/i386-ptwrite.S b/gdb/testsuite/gdb.btrace/i386-ptwrite.S
new file mode 100644
index 00000000000..5cc19c0a07a
--- /dev/null
+++ b/gdb/testsuite/gdb.btrace/i386-ptwrite.S
@@ -0,0 +1,379 @@
+/* This testcase is part of GDB, the GNU debugger.
+
+   Copyright 2022 Free Software Foundation, Inc.
+
+   Contributed by Intel Corp. <markus.t.metzger@intel.com>
+
+   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/>.
+
+
+   This file has been generated using gcc version 10.3.1 20210422
+   (Red Hat 10.3.1-1):
+   gcc -S -dA -g -m32 ptwrite.c -o i386-ptwrite.S.  */
+
+	.file	"ptwrite.c"
+	.text
+.Ltext0:
+	.globl	ptwrite64
+	.type	ptwrite64, @function
+ptwrite64:
+.LFB0:
+	.file 1 "ptwrite.c"
+	# ptwrite.c:20:1
+	.loc 1 20 1
+	.cfi_startproc
+# BLOCK 2 seq:0
+# PRED: ENTRY (FALLTHRU)
+	pushl	%ebp
+	.cfi_def_cfa_offset 8
+	.cfi_offset 5, -8
+	movl	%esp, %ebp
+	.cfi_def_cfa_register 5
+	pushl	%ebx
+	.cfi_offset 3, -12
+	# ptwrite.c:21:3
+	.loc 1 21 3
+	movl	8(%ebp), %eax
+	movl	%eax, %ebx
+#APP
+# 21 "ptwrite.c" 1
+	PTWRITE %ebx;
+# 0 "" 2
+	# ptwrite.c:22:1
+	.loc 1 22 1
+#NO_APP
+	nop
+	movl	-4(%ebp), %ebx
+	leave
+	.cfi_restore 5
+	.cfi_restore 3
+	.cfi_def_cfa 4, 4
+# SUCC: EXIT [always]
+	ret
+	.cfi_endproc
+.LFE0:
+	.size	ptwrite64, .-ptwrite64
+	.globl	ptwrite32
+	.type	ptwrite32, @function
+ptwrite32:
+.LFB1:
+	# ptwrite.c:26:1
+	.loc 1 26 1
+	.cfi_startproc
+# BLOCK 2 seq:0
+# PRED: ENTRY (FALLTHRU)
+	pushl	%ebp
+	.cfi_def_cfa_offset 8
+	.cfi_offset 5, -8
+	movl	%esp, %ebp
+	.cfi_def_cfa_register 5
+	pushl	%ebx
+	.cfi_offset 3, -12
+	# ptwrite.c:27:3
+	.loc 1 27 3
+	movl	8(%ebp), %eax
+	movl	%eax, %ebx
+#APP
+# 27 "ptwrite.c" 1
+	PTWRITE %ebx;
+# 0 "" 2
+	# ptwrite.c:28:1
+	.loc 1 28 1
+#NO_APP
+	nop
+	movl	-4(%ebp), %ebx
+	leave
+	.cfi_restore 5
+	.cfi_restore 3
+	.cfi_def_cfa 4, 4
+# SUCC: EXIT [always]
+	ret
+	.cfi_endproc
+.LFE1:
+	.size	ptwrite32, .-ptwrite32
+	.globl	main
+	.type	main, @function
+main:
+.LFB2:
+	# ptwrite.c:32:1
+	.loc 1 32 1
+	.cfi_startproc
+# BLOCK 2 seq:0
+# PRED: ENTRY (FALLTHRU)
+	pushl	%ebp
+	.cfi_def_cfa_offset 8
+	.cfi_offset 5, -8
+	movl	%esp, %ebp
+	.cfi_def_cfa_register 5
+	# ptwrite.c:33:3
+	.loc 1 33 3
+	pushl	$66
+	call	ptwrite64
+	addl	$4, %esp
+	# ptwrite.c:34:3
+	.loc 1 34 3
+	pushl	$67
+	call	ptwrite32
+	addl	$4, %esp
+	# ptwrite.c:36:10
+	.loc 1 36 10
+	movl	$0, %eax
+	# ptwrite.c:37:1
+	.loc 1 37 1
+	leave
+	.cfi_restore 5
+	.cfi_def_cfa 4, 4
+# SUCC: EXIT [always]
+	ret
+	.cfi_endproc
+.LFE2:
+	.size	main, .-main
+.Letext0:
+	.section	.debug_info,"",@progbits
+.Ldebug_info0:
+	.long	0x87	# Length of Compilation Unit Info
+	.value	0x4	# DWARF version number
+	.long	.Ldebug_abbrev0	# Offset Into Abbrev. Section
+	.byte	0x4	# Pointer Size (in bytes)
+	.uleb128 0x1	# (DIE (0xb) DW_TAG_compile_unit)
+	.long	.LASF1	# DW_AT_producer: "GNU C17 10.3.1 20210422 (Red Hat 10.3.1-1) -m32 -mtune=generic -march=i686 -g"
+	.byte	0xc	# DW_AT_language
+	.long	.LASF2	# DW_AT_name: "ptwrite.c"
+	.long	.LASF3	# DW_AT_comp_dir: "/users/fwillger/sources/gdb/gdb/testsuite/gdb.btrace"
+	.long	.Ltext0	# DW_AT_low_pc
+	.long	.Letext0-.Ltext0	# DW_AT_high_pc
+	.long	.Ldebug_line0	# DW_AT_stmt_list
+	.uleb128 0x2	# (DIE (0x25) DW_TAG_subprogram)
+			# DW_AT_external
+	.long	.LASF4	# DW_AT_name: "main"
+	.byte	0x1	# DW_AT_decl_file (ptwrite.c)
+	.byte	0x1f	# DW_AT_decl_line
+	.byte	0x1	# DW_AT_decl_column
+			# DW_AT_prototyped
+	.long	0x3b	# DW_AT_type
+	.long	.LFB2	# DW_AT_low_pc
+	.long	.LFE2-.LFB2	# DW_AT_high_pc
+	.uleb128 0x1	# DW_AT_frame_base
+	.byte	0x9c	# DW_OP_call_frame_cfa
+			# DW_AT_GNU_all_tail_call_sites
+	.uleb128 0x3	# (DIE (0x3b) DW_TAG_base_type)
+	.byte	0x4	# DW_AT_byte_size
+	.byte	0x5	# DW_AT_encoding
+	.ascii "int\0"	# DW_AT_name
+	.uleb128 0x4	# (DIE (0x42) DW_TAG_subprogram)
+			# DW_AT_external
+	.long	.LASF5	# DW_AT_name: "ptwrite32"
+	.byte	0x1	# DW_AT_decl_file (ptwrite.c)
+	.byte	0x19	# DW_AT_decl_line
+	.byte	0x1	# DW_AT_decl_column
+			# DW_AT_prototyped
+	.long	.LFB1	# DW_AT_low_pc
+	.long	.LFE1-.LFB1	# DW_AT_high_pc
+	.uleb128 0x1	# DW_AT_frame_base
+	.byte	0x9c	# DW_OP_call_frame_cfa
+			# DW_AT_GNU_all_call_sites
+	.long	0x68	# DW_AT_sibling
+	.uleb128 0x5	# (DIE (0x58) DW_TAG_formal_parameter)
+	.long	.LASF0	# DW_AT_name: "value"
+	.byte	0x1	# DW_AT_decl_file (ptwrite.c)
+	.byte	0x19	# DW_AT_decl_line
+	.byte	0x10	# DW_AT_decl_column
+	.long	0x3b	# DW_AT_type
+	.uleb128 0x2	# DW_AT_location
+	.byte	0x91	# DW_OP_fbreg
+	.sleb128 0
+	.byte	0	# end of children of DIE 0x42
+	.uleb128 0x6	# (DIE (0x68) DW_TAG_subprogram)
+			# DW_AT_external
+	.long	.LASF6	# DW_AT_name: "ptwrite64"
+	.byte	0x1	# DW_AT_decl_file (ptwrite.c)
+	.byte	0x13	# DW_AT_decl_line
+	.byte	0x1	# DW_AT_decl_column
+			# DW_AT_prototyped
+	.long	.LFB0	# DW_AT_low_pc
+	.long	.LFE0-.LFB0	# DW_AT_high_pc
+	.uleb128 0x1	# DW_AT_frame_base
+	.byte	0x9c	# DW_OP_call_frame_cfa
+			# DW_AT_GNU_all_call_sites
+	.uleb128 0x5	# (DIE (0x7a) DW_TAG_formal_parameter)
+	.long	.LASF0	# DW_AT_name: "value"
+	.byte	0x1	# DW_AT_decl_file (ptwrite.c)
+	.byte	0x13	# DW_AT_decl_line
+	.byte	0x10	# DW_AT_decl_column
+	.long	0x3b	# DW_AT_type
+	.uleb128 0x2	# DW_AT_location
+	.byte	0x91	# DW_OP_fbreg
+	.sleb128 0
+	.byte	0	# end of children of DIE 0x68
+	.byte	0	# end of children of DIE 0xb
+	.section	.debug_abbrev,"",@progbits
+.Ldebug_abbrev0:
+	.uleb128 0x1	# (abbrev code)
+	.uleb128 0x11	# (TAG: DW_TAG_compile_unit)
+	.byte	0x1	# DW_children_yes
+	.uleb128 0x25	# (DW_AT_producer)
+	.uleb128 0xe	# (DW_FORM_strp)
+	.uleb128 0x13	# (DW_AT_language)
+	.uleb128 0xb	# (DW_FORM_data1)
+	.uleb128 0x3	# (DW_AT_name)
+	.uleb128 0xe	# (DW_FORM_strp)
+	.uleb128 0x1b	# (DW_AT_comp_dir)
+	.uleb128 0xe	# (DW_FORM_strp)
+	.uleb128 0x11	# (DW_AT_low_pc)
+	.uleb128 0x1	# (DW_FORM_addr)
+	.uleb128 0x12	# (DW_AT_high_pc)
+	.uleb128 0x6	# (DW_FORM_data4)
+	.uleb128 0x10	# (DW_AT_stmt_list)
+	.uleb128 0x17	# (DW_FORM_sec_offset)
+	.byte	0
+	.byte	0
+	.uleb128 0x2	# (abbrev code)
+	.uleb128 0x2e	# (TAG: DW_TAG_subprogram)
+	.byte	0	# DW_children_no
+	.uleb128 0x3f	# (DW_AT_external)
+	.uleb128 0x19	# (DW_FORM_flag_present)
+	.uleb128 0x3	# (DW_AT_name)
+	.uleb128 0xe	# (DW_FORM_strp)
+	.uleb128 0x3a	# (DW_AT_decl_file)
+	.uleb128 0xb	# (DW_FORM_data1)
+	.uleb128 0x3b	# (DW_AT_decl_line)
+	.uleb128 0xb	# (DW_FORM_data1)
+	.uleb128 0x39	# (DW_AT_decl_column)
+	.uleb128 0xb	# (DW_FORM_data1)
+	.uleb128 0x27	# (DW_AT_prototyped)
+	.uleb128 0x19	# (DW_FORM_flag_present)
+	.uleb128 0x49	# (DW_AT_type)
+	.uleb128 0x13	# (DW_FORM_ref4)
+	.uleb128 0x11	# (DW_AT_low_pc)
+	.uleb128 0x1	# (DW_FORM_addr)
+	.uleb128 0x12	# (DW_AT_high_pc)
+	.uleb128 0x6	# (DW_FORM_data4)
+	.uleb128 0x40	# (DW_AT_frame_base)
+	.uleb128 0x18	# (DW_FORM_exprloc)
+	.uleb128 0x2116	# (DW_AT_GNU_all_tail_call_sites)
+	.uleb128 0x19	# (DW_FORM_flag_present)
+	.byte	0
+	.byte	0
+	.uleb128 0x3	# (abbrev code)
+	.uleb128 0x24	# (TAG: DW_TAG_base_type)
+	.byte	0	# DW_children_no
+	.uleb128 0xb	# (DW_AT_byte_size)
+	.uleb128 0xb	# (DW_FORM_data1)
+	.uleb128 0x3e	# (DW_AT_encoding)
+	.uleb128 0xb	# (DW_FORM_data1)
+	.uleb128 0x3	# (DW_AT_name)
+	.uleb128 0x8	# (DW_FORM_string)
+	.byte	0
+	.byte	0
+	.uleb128 0x4	# (abbrev code)
+	.uleb128 0x2e	# (TAG: DW_TAG_subprogram)
+	.byte	0x1	# DW_children_yes
+	.uleb128 0x3f	# (DW_AT_external)
+	.uleb128 0x19	# (DW_FORM_flag_present)
+	.uleb128 0x3	# (DW_AT_name)
+	.uleb128 0xe	# (DW_FORM_strp)
+	.uleb128 0x3a	# (DW_AT_decl_file)
+	.uleb128 0xb	# (DW_FORM_data1)
+	.uleb128 0x3b	# (DW_AT_decl_line)
+	.uleb128 0xb	# (DW_FORM_data1)
+	.uleb128 0x39	# (DW_AT_decl_column)
+	.uleb128 0xb	# (DW_FORM_data1)
+	.uleb128 0x27	# (DW_AT_prototyped)
+	.uleb128 0x19	# (DW_FORM_flag_present)
+	.uleb128 0x11	# (DW_AT_low_pc)
+	.uleb128 0x1	# (DW_FORM_addr)
+	.uleb128 0x12	# (DW_AT_high_pc)
+	.uleb128 0x6	# (DW_FORM_data4)
+	.uleb128 0x40	# (DW_AT_frame_base)
+	.uleb128 0x18	# (DW_FORM_exprloc)
+	.uleb128 0x2117	# (DW_AT_GNU_all_call_sites)
+	.uleb128 0x19	# (DW_FORM_flag_present)
+	.uleb128 0x1	# (DW_AT_sibling)
+	.uleb128 0x13	# (DW_FORM_ref4)
+	.byte	0
+	.byte	0
+	.uleb128 0x5	# (abbrev code)
+	.uleb128 0x5	# (TAG: DW_TAG_formal_parameter)
+	.byte	0	# DW_children_no
+	.uleb128 0x3	# (DW_AT_name)
+	.uleb128 0xe	# (DW_FORM_strp)
+	.uleb128 0x3a	# (DW_AT_decl_file)
+	.uleb128 0xb	# (DW_FORM_data1)
+	.uleb128 0x3b	# (DW_AT_decl_line)
+	.uleb128 0xb	# (DW_FORM_data1)
+	.uleb128 0x39	# (DW_AT_decl_column)
+	.uleb128 0xb	# (DW_FORM_data1)
+	.uleb128 0x49	# (DW_AT_type)
+	.uleb128 0x13	# (DW_FORM_ref4)
+	.uleb128 0x2	# (DW_AT_location)
+	.uleb128 0x18	# (DW_FORM_exprloc)
+	.byte	0
+	.byte	0
+	.uleb128 0x6	# (abbrev code)
+	.uleb128 0x2e	# (TAG: DW_TAG_subprogram)
+	.byte	0x1	# DW_children_yes
+	.uleb128 0x3f	# (DW_AT_external)
+	.uleb128 0x19	# (DW_FORM_flag_present)
+	.uleb128 0x3	# (DW_AT_name)
+	.uleb128 0xe	# (DW_FORM_strp)
+	.uleb128 0x3a	# (DW_AT_decl_file)
+	.uleb128 0xb	# (DW_FORM_data1)
+	.uleb128 0x3b	# (DW_AT_decl_line)
+	.uleb128 0xb	# (DW_FORM_data1)
+	.uleb128 0x39	# (DW_AT_decl_column)
+	.uleb128 0xb	# (DW_FORM_data1)
+	.uleb128 0x27	# (DW_AT_prototyped)
+	.uleb128 0x19	# (DW_FORM_flag_present)
+	.uleb128 0x11	# (DW_AT_low_pc)
+	.uleb128 0x1	# (DW_FORM_addr)
+	.uleb128 0x12	# (DW_AT_high_pc)
+	.uleb128 0x6	# (DW_FORM_data4)
+	.uleb128 0x40	# (DW_AT_frame_base)
+	.uleb128 0x18	# (DW_FORM_exprloc)
+	.uleb128 0x2117	# (DW_AT_GNU_all_call_sites)
+	.uleb128 0x19	# (DW_FORM_flag_present)
+	.byte	0
+	.byte	0
+	.byte	0
+	.section	.debug_aranges,"",@progbits
+	.long	0x1c	# Length of Address Ranges Info
+	.value	0x2	# DWARF aranges version
+	.long	.Ldebug_info0	# Offset of Compilation Unit Info
+	.byte	0x4	# Size of Address
+	.byte	0	# Size of Segment Descriptor
+	.value	0	# Pad to 8 byte boundary
+	.value	0
+	.long	.Ltext0	# Address
+	.long	.Letext0-.Ltext0	# Length
+	.long	0
+	.long	0
+	.section	.debug_line,"",@progbits
+.Ldebug_line0:
+	.section	.debug_str,"MS",@progbits,1
+.LASF1:
+	.string	"GNU C17 10.3.1 20210422 (Red Hat 10.3.1-1) -m32 -mtune=generic -march=i686 -g"
+.LASF6:
+	.string	"ptwrite64"
+.LASF0:
+	.string	"value"
+.LASF3:
+	.string	"/users/fwillger/sources/gdb/gdb/testsuite/gdb.btrace"
+.LASF5:
+	.string	"ptwrite32"
+.LASF2:
+	.string	"ptwrite.c"
+.LASF4:
+	.string	"main"
+	.ident	"GCC: (GNU) 10.3.1 20210422 (Red Hat 10.3.1-1)"
+	.section	.note.GNU-stack,"",@progbits
diff --git a/gdb/testsuite/gdb.btrace/ptwrite.c b/gdb/testsuite/gdb.btrace/ptwrite.c
new file mode 100644
index 00000000000..04c4f97c823
--- /dev/null
+++ b/gdb/testsuite/gdb.btrace/ptwrite.c
@@ -0,0 +1,37 @@
+/* This testcase is part of GDB, the GNU debugger.
+
+ Copyright 2021 Free Software Foundation, Inc.
+
+ 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/>.  */
+
+void
+ptwrite64 (int value)
+{
+  asm volatile ("PTWRITE %0;" : : "b" (value));
+}
+
+void
+ptwrite32 (int value)
+{
+  asm volatile ("PTWRITE %0;" : : "b" (value));
+}
+
+int
+main (void)
+{
+  ptwrite64 (0x42);
+  ptwrite32 (0x43);
+
+  return 0;
+}
diff --git a/gdb/testsuite/gdb.btrace/ptwrite.exp b/gdb/testsuite/gdb.btrace/ptwrite.exp
new file mode 100644
index 00000000000..980369bc38f
--- /dev/null
+++ b/gdb/testsuite/gdb.btrace/ptwrite.exp
@@ -0,0 +1,219 @@
+# This testcase is part of GDB, the GNU debugger.
+#
+# Copyright 2021 Free Software Foundation, Inc.
+#
+# 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/>.
+
+load_lib gdb-python.exp
+
+if { [skip_btrace_ptw_tests] } {
+    unsupported "No support for ptwrite decoding."
+    return -1
+}
+
+set opts {}
+
+if [info exists COMPILE] {
+    # make check RUNTESTFLAGS="gdb.btrace/ptwrite.exp COMPILE=1"
+    standard_testfile ptwrite.c
+    lappend opts debug
+} elseif {[istarget "i?86-*-*"] || [istarget "x86_64-*-*"]} {
+    if {[is_amd64_regs_target]} {
+	standard_testfile x86_64-ptwrite.S
+    } else {
+	standard_testfile i386-ptwrite.S
+    }
+} else {
+    unsupported "target architecture not supported"
+    return -1
+}
+
+if [prepare_for_testing "failed to prepare" $testfile $srcfile $opts] {
+    return -1
+}
+
+if { ![runto_main] } {
+    untested "failed to run to main"
+    return -1
+}
+
+# This needs to be after runto_main
+if { [skip_python_tests] } {
+    unsupported "Configuration doesn't support python scripting."
+    return -1
+}
+
+### 1. Default testrun
+
+# Setup recording
+gdb_test_no_output "set record instruction-history-size unlimited"
+gdb_test_no_output "record btrace pt"
+gdb_test "next" ".*" "first next"
+gdb_test "next" ".*" "second next"
+
+with_test_prefix "Default" {
+    # Test record instruction-history
+    gdb_test "record instruction-history 1" [multi_line \
+	".*\[0-9\]+\t   $hex <ptwrite64\\+\[0-9\]+>:\tptwrite %\[a-z\]+" \
+	"\[0-9\]+\t   \\\[42\\\]" \
+	".*\[0-9\]+\t   $hex <ptwrite32\\+\[0-9\]+>:\tptwrite %\[a-z\]+" \
+	"\[0-9\]+\t   \\\[43\\\].*" \
+	]
+
+    gdb_test "record instruction-history /a 1" [multi_line \
+	".*\[0-9\]+\t   $hex <ptwrite64\\+\[0-9\]+>:\tptwrite %\[a-z\]+" \
+	".*\[0-9\]+\t   $hex <ptwrite32\\+\[0-9\]+>:\tptwrite %\[a-z\]+.*" \
+	]
+
+    # Test function call history
+    gdb_test "record function-call-history 1,4" [multi_line \
+	"1\tmain" \
+	"2\tptwrite64" \
+	"\t\t\\\[42\\\]" \
+	"3\tmain" \
+	"4\tptwrite32" \
+	"\t\t\\\[43\\\]" \
+	]
+
+    gdb_test "record function-call-history /a 1,4" [multi_line \
+	"1\tmain" \
+	"2\tptwrite64" \
+	"3\tmain" \
+	"4\tptwrite32" \
+	]
+}
+
+# Test payload printing during stepping
+with_test_prefix "Stepping" {
+
+    # 32-bit and 64-bit have slightly different number of instructions.
+    if {[is_amd64_regs_target]} {
+	set aux_line "10"
+	set ptwrite_line "9"
+    } else {
+	set aux_line "9"
+	set ptwrite_line "8"
+    }
+
+    gdb_test "record goto $aux_line" "No such instruction\."
+    gdb_test "record goto $ptwrite_line" ".*ptwrite64.* at .*ptwrite.c:21.*"
+    gdb_test "stepi" ".*\\\[42\\\].*"
+    gdb_test "reverse-stepi" ".*\\\[42\\\].*"
+    gdb_test "continue" [multi_line \
+	    ".*\\\[42\\\]" \
+	    "\\\[43\\\].*" \
+	    ]
+    gdb_test "reverse-continue" [multi_line \
+	    ".*\\\[43\\\]" \
+	    "\\\[42\\\].*" \
+	    ]
+}
+
+# Test auxiliary type in python
+gdb_test_multiline "auxiliary type in python" \
+    "python" "" \
+    "h = gdb.current_recording().instruction_history" "" \
+    "for insn in h:" "" \
+    "    if hasattr(insn, 'decoded'):" "" \
+    "        print(insn.decoded.decode())" "" \
+    "    elif hasattr(insn, 'data'):" "" \
+    "        print(insn.data)" "" \
+    "end" \
+    [multi_line \
+	".*mov    %eax,%ebx" \
+	"ptwrite %ebx" \
+	"42" \
+	"nop.*" \
+	"mov    %eax,%ebx" \
+	"ptwrite %ebx" \
+	"43" \
+	"nop.*"
+    ]
+
+
+### 2. Test listener registration
+### 2.1 Custom listener
+with_test_prefix "Custom" {
+    gdb_test_multiline "register listener in python" \
+	"python" "" \
+	"def my_listener(payload, ip):" "" \
+	"    if  payload == 66:" "" \
+	"        return \"payload: {0}, ip: {1:#x}\".format(payload, ip)" "" \
+	"    else:" "" \
+	"        return None" "" \
+	"import gdb.ptwrite" "" \
+	"gdb.ptwrite.register_listener(my_listener)" "" \
+	"end" ""
+
+    gdb_test "record instruction-history 1" [multi_line \
+	".*\[0-9\]+\t   $hex <ptwrite64\\+\[0-9\]+>:\tptwrite %\[a-z\]+" \
+	"\[0-9\]+\t   \\\[payload: 66, ip: $hex\\\]" \
+	".*\[0-9\]+\t   $hex <ptwrite32\\+\[0-9\]+>:\tptwrite %\[a-z\]+" \
+	"\[0-9\]+\t   $hex <ptwrite32\\+\[0-9\]+>:.*" \
+	]
+}
+
+### 2.2 None as listener
+with_test_prefix "None" {
+    gdb_test_multiline "register listener in python" \
+	"python" "" \
+	"import gdb.ptwrite" "" \
+	"gdb.ptwrite.register_listener(None)" "" \
+	"end" ""
+
+    gdb_test "record instruction-history 1" [multi_line \
+	".*\[0-9\]+\t   $hex <ptwrite64\\+\[0-9\]+>:\tptwrite %\[a-z\]+" \
+	"\[0-9\]+\t   $hex <ptwrite64\\+\[0-9\]+>:.*" \
+	"\[0-9\]+\t   $hex <ptwrite32\\+\[0-9\]+>:\tptwrite %\[a-z\]+" \
+	"\[0-9\]+\t   $hex <ptwrite32\\+\[0-9\]+>:.*" \
+	]
+}
+
+### 2.3 Lambdas as listener
+with_test_prefix "Lambdas" {
+    gdb_test_multiline "register listener in python" \
+	"python" "" \
+	"import gdb.ptwrite" "" \
+	"gdb.ptwrite.register_listener(lambda payload, ip: \"{}\".format(payload + 2))" "" \
+	"end" ""
+
+    gdb_test "record instruction-history 1" [multi_line \
+	".*\[0-9\]+\t   $hex <ptwrite64\\+\[0-9\]+>:\tptwrite %\[a-z\]+" \
+	"\[0-9\]+\t   \\\[68\\\]" \
+	".*\[0-9\]+\t   $hex <ptwrite32\\+\[0-9\]+>:\tptwrite %\[a-z\]+" \
+	"\[0-9\]+\t   \\\[69\\\].*" \
+	] "Lambdas: record instruction-history 1"
+}
+
+### 2.4 Functors as listener
+with_test_prefix "Functors" {
+    gdb_test_multiline "register listener in python" \
+	"python" "" \
+	"import gdb.ptwrite" "" \
+	"class foobar(object):" "" \
+	"    def __init__(self):" "" \
+	"        self.variable = 0" "" \
+	"    def __call__(self, payload, ip):" "" \
+	"        self.variable += 1" "" \
+	"        return \"{}, {}\".format(self.variable, payload)" "" \
+	"gdb.ptwrite.register_listener(foobar())" "" \
+	"end" ""
+
+    gdb_test "record instruction-history 1" [multi_line \
+	".*\[0-9\]+\t   $hex <ptwrite64\\+\[0-9\]+>:\tptwrite %\[a-z\]+" \
+	"\[0-9\]+\t   \\\[1, 66\\\]" \
+	".*\[0-9\]+\t   $hex <ptwrite32\\+\[0-9\]+>:\tptwrite %\[a-z\]+" \
+	"\[0-9\]+\t   \\\[2, 67\\\].*" \
+	] "Functors: record instruction-history 1"
+}
diff --git a/gdb/testsuite/gdb.btrace/x86_64-ptwrite.S b/gdb/testsuite/gdb.btrace/x86_64-ptwrite.S
new file mode 100644
index 00000000000..3dc03bdfdbe
--- /dev/null
+++ b/gdb/testsuite/gdb.btrace/x86_64-ptwrite.S
@@ -0,0 +1,374 @@
+/* This testcase is part of GDB, the GNU debugger.
+
+   Copyright 2022 Free Software Foundation, Inc.
+
+   Contributed by Intel Corp. <markus.t.metzger@intel.com>
+
+   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/>.
+
+
+   This file has been generated using gcc version 10.3.1 20210422
+   (Red Hat 10.3.1-1):
+   gcc -S -dA -g ptwrite.c -o x86_64-ptwrite.S.  */
+
+	.file	"ptwrite.c"
+	.text
+.Ltext0:
+	.globl	ptwrite64
+	.type	ptwrite64, @function
+ptwrite64:
+.LFB0:
+	.file 1 "ptwrite.c"
+	# ptwrite.c:20:1
+	.loc 1 20 1
+	.cfi_startproc
+# BLOCK 2 seq:0
+# PRED: ENTRY (FALLTHRU)
+	pushq	%rbp
+	.cfi_def_cfa_offset 16
+	.cfi_offset 6, -16
+	movq	%rsp, %rbp
+	.cfi_def_cfa_register 6
+	pushq	%rbx
+	.cfi_offset 3, -24
+	movl	%edi, -12(%rbp)
+	# ptwrite.c:21:3
+	.loc 1 21 3
+	movl	-12(%rbp), %eax
+	movl	%eax, %ebx
+#APP
+# 21 "ptwrite.c" 1
+	PTWRITE %ebx;
+# 0 "" 2
+	# ptwrite.c:22:1
+	.loc 1 22 1
+#NO_APP
+	nop
+	movq	-8(%rbp), %rbx
+	leave
+	.cfi_def_cfa 7, 8
+# SUCC: EXIT [always] 
+	ret
+	.cfi_endproc
+.LFE0:
+	.size	ptwrite64, .-ptwrite64
+	.globl	ptwrite32
+	.type	ptwrite32, @function
+ptwrite32:
+.LFB1:
+	# ptwrite.c:26:1
+	.loc 1 26 1
+	.cfi_startproc
+# BLOCK 2 seq:0
+# PRED: ENTRY (FALLTHRU)
+	pushq	%rbp
+	.cfi_def_cfa_offset 16
+	.cfi_offset 6, -16
+	movq	%rsp, %rbp
+	.cfi_def_cfa_register 6
+	pushq	%rbx
+	.cfi_offset 3, -24
+	movl	%edi, -12(%rbp)
+	# ptwrite.c:27:3
+	.loc 1 27 3
+	movl	-12(%rbp), %eax
+	movl	%eax, %ebx
+#APP
+# 27 "ptwrite.c" 1
+	PTWRITE %ebx;
+# 0 "" 2
+	# ptwrite.c:28:1
+	.loc 1 28 1
+#NO_APP
+	nop
+	movq	-8(%rbp), %rbx
+	leave
+	.cfi_def_cfa 7, 8
+# SUCC: EXIT [always] 
+	ret
+	.cfi_endproc
+.LFE1:
+	.size	ptwrite32, .-ptwrite32
+	.globl	main
+	.type	main, @function
+main:
+.LFB2:
+	# ptwrite.c:32:1
+	.loc 1 32 1
+	.cfi_startproc
+# BLOCK 2 seq:0
+# PRED: ENTRY (FALLTHRU)
+	pushq	%rbp
+	.cfi_def_cfa_offset 16
+	.cfi_offset 6, -16
+	movq	%rsp, %rbp
+	.cfi_def_cfa_register 6
+	# ptwrite.c:33:3
+	.loc 1 33 3
+	movl	$66, %edi
+	call	ptwrite64
+	# ptwrite.c:34:3
+	.loc 1 34 3
+	movl	$67, %edi
+	call	ptwrite32
+	# ptwrite.c:36:10
+	.loc 1 36 10
+	movl	$0, %eax
+	# ptwrite.c:37:1
+	.loc 1 37 1
+	popq	%rbp
+	.cfi_def_cfa 7, 8
+# SUCC: EXIT [always] 
+	ret
+	.cfi_endproc
+.LFE2:
+	.size	main, .-main
+.Letext0:
+	.section	.debug_info,"",@progbits
+.Ldebug_info0:
+	.long	0xa7	# Length of Compilation Unit Info
+	.value	0x4	# DWARF version number
+	.long	.Ldebug_abbrev0	# Offset Into Abbrev. Section
+	.byte	0x8	# Pointer Size (in bytes)
+	.uleb128 0x1	# (DIE (0xb) DW_TAG_compile_unit)
+	.long	.LASF1	# DW_AT_producer: "GNU C17 10.3.1 20210422 (Red Hat 10.3.1-1) -mtune=generic -march=x86-64 -g"
+	.byte	0xc	# DW_AT_language
+	.long	.LASF2	# DW_AT_name: "ptwrite.c"
+	.long	.LASF3	# DW_AT_comp_dir: "/users/fwillger/sources/gdb/gdb/testsuite/gdb.btrace"
+	.quad	.Ltext0	# DW_AT_low_pc
+	.quad	.Letext0-.Ltext0	# DW_AT_high_pc
+	.long	.Ldebug_line0	# DW_AT_stmt_list
+	.uleb128 0x2	# (DIE (0x2d) DW_TAG_subprogram)
+			# DW_AT_external
+	.long	.LASF4	# DW_AT_name: "main"
+	.byte	0x1	# DW_AT_decl_file (ptwrite.c)
+	.byte	0x1f	# DW_AT_decl_line
+	.byte	0x1	# DW_AT_decl_column
+			# DW_AT_prototyped
+	.long	0x4b	# DW_AT_type
+	.quad	.LFB2	# DW_AT_low_pc
+	.quad	.LFE2-.LFB2	# DW_AT_high_pc
+	.uleb128 0x1	# DW_AT_frame_base
+	.byte	0x9c	# DW_OP_call_frame_cfa
+			# DW_AT_GNU_all_tail_call_sites
+	.uleb128 0x3	# (DIE (0x4b) DW_TAG_base_type)
+	.byte	0x4	# DW_AT_byte_size
+	.byte	0x5	# DW_AT_encoding
+	.ascii "int\0"	# DW_AT_name
+	.uleb128 0x4	# (DIE (0x52) DW_TAG_subprogram)
+			# DW_AT_external
+	.long	.LASF5	# DW_AT_name: "ptwrite32"
+	.byte	0x1	# DW_AT_decl_file (ptwrite.c)
+	.byte	0x19	# DW_AT_decl_line
+	.byte	0x1	# DW_AT_decl_column
+			# DW_AT_prototyped
+	.quad	.LFB1	# DW_AT_low_pc
+	.quad	.LFE1-.LFB1	# DW_AT_high_pc
+	.uleb128 0x1	# DW_AT_frame_base
+	.byte	0x9c	# DW_OP_call_frame_cfa
+			# DW_AT_GNU_all_call_sites
+	.long	0x80	# DW_AT_sibling
+	.uleb128 0x5	# (DIE (0x70) DW_TAG_formal_parameter)
+	.long	.LASF0	# DW_AT_name: "value"
+	.byte	0x1	# DW_AT_decl_file (ptwrite.c)
+	.byte	0x19	# DW_AT_decl_line
+	.byte	0x10	# DW_AT_decl_column
+	.long	0x4b	# DW_AT_type
+	.uleb128 0x2	# DW_AT_location
+	.byte	0x91	# DW_OP_fbreg
+	.sleb128 -28
+	.byte	0	# end of children of DIE 0x52
+	.uleb128 0x6	# (DIE (0x80) DW_TAG_subprogram)
+			# DW_AT_external
+	.long	.LASF6	# DW_AT_name: "ptwrite64"
+	.byte	0x1	# DW_AT_decl_file (ptwrite.c)
+	.byte	0x13	# DW_AT_decl_line
+	.byte	0x1	# DW_AT_decl_column
+			# DW_AT_prototyped
+	.quad	.LFB0	# DW_AT_low_pc
+	.quad	.LFE0-.LFB0	# DW_AT_high_pc
+	.uleb128 0x1	# DW_AT_frame_base
+	.byte	0x9c	# DW_OP_call_frame_cfa
+			# DW_AT_GNU_all_call_sites
+	.uleb128 0x5	# (DIE (0x9a) DW_TAG_formal_parameter)
+	.long	.LASF0	# DW_AT_name: "value"
+	.byte	0x1	# DW_AT_decl_file (ptwrite.c)
+	.byte	0x13	# DW_AT_decl_line
+	.byte	0x10	# DW_AT_decl_column
+	.long	0x4b	# DW_AT_type
+	.uleb128 0x2	# DW_AT_location
+	.byte	0x91	# DW_OP_fbreg
+	.sleb128 -28
+	.byte	0	# end of children of DIE 0x80
+	.byte	0	# end of children of DIE 0xb
+	.section	.debug_abbrev,"",@progbits
+.Ldebug_abbrev0:
+	.uleb128 0x1	# (abbrev code)
+	.uleb128 0x11	# (TAG: DW_TAG_compile_unit)
+	.byte	0x1	# DW_children_yes
+	.uleb128 0x25	# (DW_AT_producer)
+	.uleb128 0xe	# (DW_FORM_strp)
+	.uleb128 0x13	# (DW_AT_language)
+	.uleb128 0xb	# (DW_FORM_data1)
+	.uleb128 0x3	# (DW_AT_name)
+	.uleb128 0xe	# (DW_FORM_strp)
+	.uleb128 0x1b	# (DW_AT_comp_dir)
+	.uleb128 0xe	# (DW_FORM_strp)
+	.uleb128 0x11	# (DW_AT_low_pc)
+	.uleb128 0x1	# (DW_FORM_addr)
+	.uleb128 0x12	# (DW_AT_high_pc)
+	.uleb128 0x7	# (DW_FORM_data8)
+	.uleb128 0x10	# (DW_AT_stmt_list)
+	.uleb128 0x17	# (DW_FORM_sec_offset)
+	.byte	0
+	.byte	0
+	.uleb128 0x2	# (abbrev code)
+	.uleb128 0x2e	# (TAG: DW_TAG_subprogram)
+	.byte	0	# DW_children_no
+	.uleb128 0x3f	# (DW_AT_external)
+	.uleb128 0x19	# (DW_FORM_flag_present)
+	.uleb128 0x3	# (DW_AT_name)
+	.uleb128 0xe	# (DW_FORM_strp)
+	.uleb128 0x3a	# (DW_AT_decl_file)
+	.uleb128 0xb	# (DW_FORM_data1)
+	.uleb128 0x3b	# (DW_AT_decl_line)
+	.uleb128 0xb	# (DW_FORM_data1)
+	.uleb128 0x39	# (DW_AT_decl_column)
+	.uleb128 0xb	# (DW_FORM_data1)
+	.uleb128 0x27	# (DW_AT_prototyped)
+	.uleb128 0x19	# (DW_FORM_flag_present)
+	.uleb128 0x49	# (DW_AT_type)
+	.uleb128 0x13	# (DW_FORM_ref4)
+	.uleb128 0x11	# (DW_AT_low_pc)
+	.uleb128 0x1	# (DW_FORM_addr)
+	.uleb128 0x12	# (DW_AT_high_pc)
+	.uleb128 0x7	# (DW_FORM_data8)
+	.uleb128 0x40	# (DW_AT_frame_base)
+	.uleb128 0x18	# (DW_FORM_exprloc)
+	.uleb128 0x2116	# (DW_AT_GNU_all_tail_call_sites)
+	.uleb128 0x19	# (DW_FORM_flag_present)
+	.byte	0
+	.byte	0
+	.uleb128 0x3	# (abbrev code)
+	.uleb128 0x24	# (TAG: DW_TAG_base_type)
+	.byte	0	# DW_children_no
+	.uleb128 0xb	# (DW_AT_byte_size)
+	.uleb128 0xb	# (DW_FORM_data1)
+	.uleb128 0x3e	# (DW_AT_encoding)
+	.uleb128 0xb	# (DW_FORM_data1)
+	.uleb128 0x3	# (DW_AT_name)
+	.uleb128 0x8	# (DW_FORM_string)
+	.byte	0
+	.byte	0
+	.uleb128 0x4	# (abbrev code)
+	.uleb128 0x2e	# (TAG: DW_TAG_subprogram)
+	.byte	0x1	# DW_children_yes
+	.uleb128 0x3f	# (DW_AT_external)
+	.uleb128 0x19	# (DW_FORM_flag_present)
+	.uleb128 0x3	# (DW_AT_name)
+	.uleb128 0xe	# (DW_FORM_strp)
+	.uleb128 0x3a	# (DW_AT_decl_file)
+	.uleb128 0xb	# (DW_FORM_data1)
+	.uleb128 0x3b	# (DW_AT_decl_line)
+	.uleb128 0xb	# (DW_FORM_data1)
+	.uleb128 0x39	# (DW_AT_decl_column)
+	.uleb128 0xb	# (DW_FORM_data1)
+	.uleb128 0x27	# (DW_AT_prototyped)
+	.uleb128 0x19	# (DW_FORM_flag_present)
+	.uleb128 0x11	# (DW_AT_low_pc)
+	.uleb128 0x1	# (DW_FORM_addr)
+	.uleb128 0x12	# (DW_AT_high_pc)
+	.uleb128 0x7	# (DW_FORM_data8)
+	.uleb128 0x40	# (DW_AT_frame_base)
+	.uleb128 0x18	# (DW_FORM_exprloc)
+	.uleb128 0x2117	# (DW_AT_GNU_all_call_sites)
+	.uleb128 0x19	# (DW_FORM_flag_present)
+	.uleb128 0x1	# (DW_AT_sibling)
+	.uleb128 0x13	# (DW_FORM_ref4)
+	.byte	0
+	.byte	0
+	.uleb128 0x5	# (abbrev code)
+	.uleb128 0x5	# (TAG: DW_TAG_formal_parameter)
+	.byte	0	# DW_children_no
+	.uleb128 0x3	# (DW_AT_name)
+	.uleb128 0xe	# (DW_FORM_strp)
+	.uleb128 0x3a	# (DW_AT_decl_file)
+	.uleb128 0xb	# (DW_FORM_data1)
+	.uleb128 0x3b	# (DW_AT_decl_line)
+	.uleb128 0xb	# (DW_FORM_data1)
+	.uleb128 0x39	# (DW_AT_decl_column)
+	.uleb128 0xb	# (DW_FORM_data1)
+	.uleb128 0x49	# (DW_AT_type)
+	.uleb128 0x13	# (DW_FORM_ref4)
+	.uleb128 0x2	# (DW_AT_location)
+	.uleb128 0x18	# (DW_FORM_exprloc)
+	.byte	0
+	.byte	0
+	.uleb128 0x6	# (abbrev code)
+	.uleb128 0x2e	# (TAG: DW_TAG_subprogram)
+	.byte	0x1	# DW_children_yes
+	.uleb128 0x3f	# (DW_AT_external)
+	.uleb128 0x19	# (DW_FORM_flag_present)
+	.uleb128 0x3	# (DW_AT_name)
+	.uleb128 0xe	# (DW_FORM_strp)
+	.uleb128 0x3a	# (DW_AT_decl_file)
+	.uleb128 0xb	# (DW_FORM_data1)
+	.uleb128 0x3b	# (DW_AT_decl_line)
+	.uleb128 0xb	# (DW_FORM_data1)
+	.uleb128 0x39	# (DW_AT_decl_column)
+	.uleb128 0xb	# (DW_FORM_data1)
+	.uleb128 0x27	# (DW_AT_prototyped)
+	.uleb128 0x19	# (DW_FORM_flag_present)
+	.uleb128 0x11	# (DW_AT_low_pc)
+	.uleb128 0x1	# (DW_FORM_addr)
+	.uleb128 0x12	# (DW_AT_high_pc)
+	.uleb128 0x7	# (DW_FORM_data8)
+	.uleb128 0x40	# (DW_AT_frame_base)
+	.uleb128 0x18	# (DW_FORM_exprloc)
+	.uleb128 0x2117	# (DW_AT_GNU_all_call_sites)
+	.uleb128 0x19	# (DW_FORM_flag_present)
+	.byte	0
+	.byte	0
+	.byte	0
+	.section	.debug_aranges,"",@progbits
+	.long	0x2c	# Length of Address Ranges Info
+	.value	0x2	# DWARF aranges version
+	.long	.Ldebug_info0	# Offset of Compilation Unit Info
+	.byte	0x8	# Size of Address
+	.byte	0	# Size of Segment Descriptor
+	.value	0	# Pad to 16 byte boundary
+	.value	0
+	.quad	.Ltext0	# Address
+	.quad	.Letext0-.Ltext0	# Length
+	.quad	0
+	.quad	0
+	.section	.debug_line,"",@progbits
+.Ldebug_line0:
+	.section	.debug_str,"MS",@progbits,1
+.LASF3:
+	.string	"/users/fwillger/sources/gdb/gdb/testsuite/gdb.btrace"
+.LASF6:
+	.string	"ptwrite64"
+.LASF0:
+	.string	"value"
+.LASF1:
+	.string	"GNU C17 10.3.1 20210422 (Red Hat 10.3.1-1) -mtune=generic -march=x86-64 -g"
+.LASF5:
+	.string	"ptwrite32"
+.LASF2:
+	.string	"ptwrite.c"
+.LASF4:
+	.string	"main"
+	.ident	"GCC: (GNU) 10.3.1 20210422 (Red Hat 10.3.1-1)"
+	.section	.note.GNU-stack,"",@progbits
diff --git a/gdb/testsuite/lib/gdb.exp b/gdb/testsuite/lib/gdb.exp
index 47cb2b23676..a156052595b 100644
--- a/gdb/testsuite/lib/gdb.exp
+++ b/gdb/testsuite/lib/gdb.exp
@@ -3635,6 +3635,159 @@ gdb_caching_proc skip_btrace_pt_tests {
     return $skip_btrace_tests
 }
 
+# Run a test on the target to see if it supports ptwrite instructions and
+# if GDB can decode ptwrite events.  Return 0 if so, 1 if it does not.
+
+gdb_caching_proc skip_btrace_ptw_tests {
+    global srcdir subdir gdb_prompt inferior_exited_re decimal
+
+    set me "skip_ptw_tests"
+    if { [skip_btrace_pt_tests] } {
+	verbose "$me:  target does not support btrace, returning 1" 2
+	return 1
+    }
+
+    set src {
+	#include <stdbool.h>
+	#include <stdio.h>
+
+	bool
+	linux_supports_ptwrite ()
+	{
+	  static const char filename[]
+	    = "/sys/bus/event_source/devices/intel_pt/caps/ptwrite";
+	  FILE *file = fopen (filename, "r");
+
+	  if (file == NULL)
+	    return false;
+
+	  int status, found = fscanf (file, "%d", &status);
+	  fclose (file);
+
+	  if (found != 1)
+	    return false;
+
+	  return status == 1;
+	}
+
+	int
+	main ()
+	{
+	  if (linux_supports_ptwrite ())
+	    {
+	      asm volatile ("PTWRITE %0;" : : "b"(0x42));
+	      return 1; /* BP1. */
+	    }
+	  return 0;
+	}
+    }
+
+    if {![gdb_simple_compile $me $src executable]} {
+        return 1
+    }
+
+    gdb_exit
+    gdb_start
+    gdb_reinitialize_dir $srcdir/$subdir
+    gdb_load "$obj"
+    if ![runto_main] {
+        return 1
+    }
+
+    gdb_breakpoint "29"
+    gdb_breakpoint "30"
+    gdb_continue_to_breakpoint "$me: continue to first bp" ".*:29.*"
+    gdb_test_no_output "record btrace pt" "$me: record btrace pt"
+
+    set skip_ptw_tests 2
+    gdb_test_multiple "continue" "$me: continue" {
+        -re ".*Illegal instruction.*${gdb_prompt} $" {
+            verbose -log "$me:  ptwrite instruction support not detected."
+            set skip_ptw_tests 2
+        }
+        -re ".*$inferior_exited_re normally.*${gdb_prompt} $" {
+            verbose -log "$me:  ptwrite support not detected."
+            set skip_ptw_tests 2
+        }
+        -re "Breakpoint .* (at|in) .*:30.*" {
+            set skip_ptw_tests 1
+        }
+    }
+
+    if { $skip_ptw_tests == 1 } {
+	# Show the func-call-history to get the packet trace.
+	gdb_test "record function-call-history" ".*"
+
+	gdb_test_multiple "maintenance btrace packet-history 0,1000" \
+	    "$me: check decoding support" {
+	    -re  "ptw" {
+		verbose -log "$me:  ptwrite decoding support detected."
+		set skip_ptw_tests 0
+	    }
+	    -re ".*${gdb_prompt} $" {
+		verbose -log "$me:  ptwrite decoding support not detected."
+	    }
+	}
+    }
+
+    gdb_exit
+    remote_file build delete $obj
+
+    verbose "$me:  returning $skip_ptw_tests" 2
+    return $skip_ptw_tests
+}
+
+# Run a test on the target to see if we have a minimum libipt version.
+# Return 0 if so, 1 if it does not.
+
+proc require_libipt_version { major minor revision } {
+    global srcdir subdir gdb_prompt inferior_exited_re
+
+    set me "libipt_version_tests"
+    if { ![istarget "i?86-*-*"] && ![istarget "x86_64-*-*"] } {
+        verbose "$me:  target does not support btrace, returning 1" 2
+        return 1
+    }
+
+    # Compile a test program.
+    set src { int main() { return 0; } }
+    if {![gdb_simple_compile $me $src executable]} {
+        return 1
+    }
+
+    # No error message, compilation succeeded so now run it via gdb.
+
+    gdb_exit
+    gdb_start
+    gdb_reinitialize_dir $srcdir/$subdir
+    gdb_load $obj
+    if ![runto_main] {
+        return 1
+    }
+
+    gdb_test_no_output "record btrace pt" "$me: record btrace pt"
+    set actual_major ""
+    set actual_minor ""
+    set actual_revision ""
+    gdb_test_multiple "maint info btrace" "$me: maint info btrace" {
+	-re ".*Version: (\[0-9\]+)\.(\[0-9\]+)\.(\[0-9\]+).*$gdb_prompt $" {
+	    append actual_major $expect_out(1,string)
+	    append actual_minor $expect_out(2,string)
+	    append actual_revision $expect_out(3,string)
+	}
+	default {}
+    }
+
+    gdb_exit
+    remote_file build delete $obj
+
+    verbose "$me: Using version: $actual_major.$actual_minor.$actual_revision" 2
+    verbose "$me: Required minimum version: $major.$minor.$revision" 2
+
+    return [expr ![version_at_least $actual_major $actual_minor \
+		   $actual_revision $major $minor $revision]]
+}
+
 # Run a test on the target to see if it supports Aarch64 SVE hardware.
 # Return 0 if so, 1 if it does not.  Note this causes a restart of GDB.
 
diff --git a/gdbsupport/common.m4 b/gdbsupport/common.m4
index d3e9ecbe823..aebf484b515 100644
--- a/gdbsupport/common.m4
+++ b/gdbsupport/common.m4
@@ -179,6 +179,8 @@ AC_DEFUN([GDB_AC_COMMON], [
       AC_CHECK_FUNCS(pt_insn_event)
       AC_CHECK_MEMBERS([struct pt_insn.enabled, struct pt_insn.resynced], [], [],
 		       [#include <intel-pt.h>])
+      AC_CHECK_MEMBERS([struct pt_event.variant.ptwrite], [], [],
+		       [#include <intel-pt.h>])
       LIBS=$save_LIBS
     fi
   fi
diff --git a/gdbsupport/config.in b/gdbsupport/config.in
index a7ae23b4984..3d5543cb7b5 100644
--- a/gdbsupport/config.in
+++ b/gdbsupport/config.in
@@ -232,6 +232,9 @@
 /* Define to 1 if you have the <string.h> header file. */
 #undef HAVE_STRING_H
 
+/* Define to 1 if `variant.ptwrite' is a member of `struct pt_event'. */
+#undef HAVE_STRUCT_PT_EVENT_VARIANT_PTWRITE
+
 /* Define to 1 if `enabled' is a member of `struct pt_insn'. */
 #undef HAVE_STRUCT_PT_INSN_ENABLED
 
diff --git a/gdbsupport/configure b/gdbsupport/configure
index 618f487749f..1f4f3ff02a5 100755
--- a/gdbsupport/configure
+++ b/gdbsupport/configure
@@ -9604,6 +9604,17 @@ cat >>confdefs.h <<_ACEOF
 _ACEOF
 
 
+fi
+
+      ac_fn_c_check_member "$LINENO" "struct pt_event" "variant.ptwrite" "ac_cv_member_struct_pt_event_variant_ptwrite" "#include <intel-pt.h>
+"
+if test "x$ac_cv_member_struct_pt_event_variant_ptwrite" = xyes; then :
+
+cat >>confdefs.h <<_ACEOF
+#define HAVE_STRUCT_PT_EVENT_VARIANT_PTWRITE 1
+_ACEOF
+
+
 fi
 
       LIBS=$save_LIBS
-- 
2.34.1

Intel Deutschland GmbH
Registered Address: Am Campeon 10, 85579 Neubiberg, Germany
Tel: +49 89 99 8853-0, www.intel.de <http://www.intel.de>
Managing Directors: Christin Eisenschmid, Sharon Heck, Tiffany Doon Silva  
Chairperson of the Supervisory Board: Nicole Lau
Registered Office: Munich
Commercial Register: Amtsgericht Muenchen HRB 186928

Re: [PATCH v4 02/10] btrace: Enable auxiliary instructions in record instruction-history.

[Eli Zaretskii]

> Date: Fri,  6 May 2022 13:40:02 +0200
> From: Felix Willgerodt via Gdb-patches <gdb-patches@sourceware.org>
> 
> Print the auxiliary data when a btrace_insn of type BTRACE_INSN_AUX
> is encountered in the instruction-history.  Printing is active by default,
> it can be silenced with the /a modifier.
> 
> This patch is in preparation for the new ptwrite feature, which is based on
> auxiliary instructions.
> ---
>  gdb/disasm-flags.h  |  1 +
>  gdb/doc/gdb.texinfo |  3 +++
>  gdb/record-btrace.c | 14 ++++++++++++++
>  gdb/record.c        |  5 +++++
>  4 files changed, 23 insertions(+)

OK for the documentation part.

Thanks.

Re: [PATCH v4 01/10] btrace: Introduce auxiliary instructions.

[Eli Zaretskii]

> Date: Fri,  6 May 2022 13:40:01 +0200
> From: Felix Willgerodt via Gdb-patches <gdb-patches@sourceware.org>
> 
> diff --git a/gdb/doc/gdb.texinfo b/gdb/doc/gdb.texinfo
> index 38ad2ac32b0..ec45055e914 100644
> --- a/gdb/doc/gdb.texinfo
> +++ b/gdb/doc/gdb.texinfo
> @@ -7485,6 +7485,10 @@ Moxie, PowerPC, PowerPC64, S/390, and x86 (i386/amd64) running
>  GNU/Linux.  Process record and replay can be used both when native
>  debugging, and when remote debugging via @code{gdbserver}.
>  
> +When recording an inferior, @value{GDBN} may print additional auxiliary
> +information during stepping commands and commands displaying the execution
> +history.
> +

I wonder why we need this addition.  What is the significance of
mentioning this factoid in the manual at that place?

Thanks.

Re: [PATCH v4 03/10] btrace: Enable auxiliary instructions in record function-call-history.

[Eli Zaretskii]

> Date: Fri,  6 May 2022 13:40:03 +0200
> From: Felix Willgerodt via Gdb-patches <gdb-patches@sourceware.org>
> 
> Print the auxiliary data when a btrace_insn of type BTRACE_INSN_AUX
> is encountered in the function-call-history.  Printing is
> active by default, it can be silenced with the /a modifier.
> 
> This patch is in preparation for the new ptwrite feature, which is based on
> auxiliary instructions.
> ---
>  gdb/btrace.h        |  6 +++++-
>  gdb/doc/gdb.texinfo |  5 +++--
>  gdb/record-btrace.c | 21 +++++++++++++++++++++
>  gdb/record.c        |  5 +++++
>  gdb/record.h        |  5 ++++-
>  5 files changed, 38 insertions(+), 4 deletions(-)

Thanks, the documentation changes are OK.

Re: [PATCH v4 05/10] python: Introduce gdb.RecordAuxiliary class.

[Eli Zaretskii]

> Date: Fri,  6 May 2022 13:40:05 +0200
> From: Felix Willgerodt via Gdb-patches <gdb-patches@sourceware.org>
> 
> Auxiliary instructions are no real instructions and get their own object
> class, similar to gaps. gdb.Record.instruction_history is now possibly a
> list of gdb.RecordInstruction, gdb.RecordGap or gdb.RecordAuxiliary
> objects.
> 
> This patch is in preparation for the new ptwrite feature, which is based on
> auxiliary instructions.
> ---
>  gdb/doc/python.texi           | 13 +++++++
>  gdb/python/py-record-btrace.c | 34 ++++++++++------
>  gdb/python/py-record.c        | 73 ++++++++++++++++++++++++++++++++++-
>  gdb/python/py-record.h        |  3 ++
>  4 files changed, 110 insertions(+), 13 deletions(-)

OK for the documentation part, thanks.

Re: [PATCH v4 06/10] python: Add clear() to gdb.Record.

[Eli Zaretskii]

> Date: Fri,  6 May 2022 13:40:06 +0200
> From: Felix Willgerodt via Gdb-patches <gdb-patches@sourceware.org>
> 
> This function allows to clear the trace data from python, forcing to
> re-decode the trace for successive commands.
> ---
>  gdb/doc/python.texi                           |  5 +++++
>  gdb/python/py-record-btrace.c                 | 13 +++++++++++++
>  gdb/python/py-record-btrace.h                 |  3 +++
>  gdb/python/py-record.c                        | 16 ++++++++++++++++
>  gdb/testsuite/gdb.python/py-record-btrace.exp |  6 +++++-
>  5 files changed, 42 insertions(+), 1 deletion(-)
> 
> diff --git a/gdb/doc/python.texi b/gdb/doc/python.texi
> index 142dbc719a4..707aa5c3ee3 100644
> --- a/gdb/doc/python.texi
> +++ b/gdb/doc/python.texi
> @@ -3779,6 +3779,11 @@ A @code{gdb.Record} object has the following methods:
>  Move the replay position to the given @var{instruction}.
>  @end defun
>  
> +@defun Record.clear ()
> +Clear the trace data of the current recording.  This forces re-decoding of the
> +trace for successive commands.
> +@end defun

What does "force re-decoding" mean here?  If this is described in
another place in the manual, could you add a cross-reference to that
place?

Otherwise, the documentation part is OK, thanks.

Re: [PATCH v4 07/10] btrace, gdbserver: Add ptwrite to btrace_config_pt.

[Eli Zaretskii]

> Date: Fri,  6 May 2022 13:40:07 +0200
> From: Felix Willgerodt via Gdb-patches <gdb-patches@sourceware.org>
> 
> +@item Qbtrace-conf:pt:ptwrite=@var{value}
> +Control recording of ptwrite packets.  This was added for backwards-
> +compatibility.

Suggest to rephrase the second sentence to remove "was added".  The
manual is supposed to describe the current situation, not the history
(which becomes less and less relevant as time goes by).

The documentation part is okay with this not fixed.

Thanks.

Re: [PATCH v4 10/10] btrace: Extend ptwrite event decoding.

[Eli Zaretskii]

> Date: Fri,  6 May 2022 13:40:10 +0200
> From: Felix Willgerodt via Gdb-patches <gdb-patches@sourceware.org>
> 
> diff --git a/gdb/NEWS b/gdb/NEWS
> index a72fee81550..cf807d6209e 100644
> --- a/gdb/NEWS
> +++ b/gdb/NEWS
> @@ -331,6 +331,12 @@ GNU/Linux/OpenRISC		or1k*-*-linux*
>  
>  *** Changes in GDB 11
>  
> +* GDB now supports printing of ptwrite payloads from the Intel Processor
> +  Trace during 'record instruction-history', 'record function-call-history',
> +  all stepping commands and in  Python.  Printing is customizable via a
> +  ptwrite listener function in  Python.  By default, the raw ptwrite
> +  payload is printed for each ptwrite that is encountered.
> +

This part is OK.

> +@exdent @value{GDBN} output after recording the sample program in pt format:
> +@smallexample
> +@group
> +(gdb) record instruction-history 12,14
> +12         0x000000000040074c <ptwrite64+16>:	ptwrite %rbx
> +13         [42]
> +14         0x0000000000400751 <ptwrite64+21>:	mov    -0x8(%rbp),%rbx

The last line is too long, and will cause overfull hbox errors when
producing the printed manual.  Please make it shorter, or break into 2
lines.

> +@findex gdb.ptwrite.register_listener
> +@defun register_listener (@var{listener})

@defun automatically inserts the function into the index, so no need
for a separate @findex (here and elsewhere in the patch).

> +Used to register the ptwrite listener.  The listener can be any callable
> +object that accepts two arguments.

I think we should describe those 2 arguments, at least shortly.

> +@defun default_listener (@var{payload}, @var{ip})
> +The listener function active by default.

Which does what?  If we don't say anything about the default behavior,
how can a user decide whether to provide his/her specialized listener?

> +@smallexample
> +@group
> +(gdb) python-interactive
> +>>> class my_listener(object):
> +...    def __init__(self):
> +...        self.var = 0
> +...    def __call__(self, payload, ip):
> +...        if gdb.selected_thread().global_num == 1:
> +...            self.var += 1
> +...            return "counter: @{@}, ip: @{:#x@}".format(self.var, ip)

This last line is too long.

(And I wonder whether this example really adds something of value to
what you already described above.)

> +@group
> +(gdb) info threads 
> +* 1    Thread 0x7ffff7fd8740 (LWP 25796) "ptwrite_threads" task (arg=0x0)
> +    at bin/ptwrite/ptwrite_threads.c:45
> +  2    Thread 0x7ffff6eb8700 (LWP 25797) "ptwrite_threads" task (arg=0x0)
> +    at bin/ptwrite/ptwrite_threads.c:45

These lines are also too long.

> +This @value{GDBN} feature is dependent on hardware and operating system
> +support and requires the Intel Processor Trace decoder library in version
> +2.0.0 or newer.

You say "hardware and operating system support", but say nothing about
the OSes on which this can be supported.

Thanks.

RE: [PATCH v4 01/10] btrace: Introduce auxiliary instructions.

[Willgerodt, Felix]

> -----Original Message-----
> From: Eli Zaretskii <eliz@gnu.org>
> Sent: Freitag, 6. Mai 2022 13:48
> To: Willgerodt, Felix <felix.willgerodt@intel.com>
> Cc: Metzger, Markus T <markus.t.metzger@intel.com>; gdb-
> patches@sourceware.org
> Subject: Re: [PATCH v4 01/10] btrace: Introduce auxiliary instructions.
> 
> > Date: Fri,  6 May 2022 13:40:01 +0200
> > From: Felix Willgerodt via Gdb-patches <gdb-patches@sourceware.org>
> >
> > diff --git a/gdb/doc/gdb.texinfo b/gdb/doc/gdb.texinfo
> > index 38ad2ac32b0..ec45055e914 100644
> > --- a/gdb/doc/gdb.texinfo
> > +++ b/gdb/doc/gdb.texinfo
> > @@ -7485,6 +7485,10 @@ Moxie, PowerPC, PowerPC64, S/390, and x86
> (i386/amd64) running
> >  GNU/Linux.  Process record and replay can be used both when native
> >  debugging, and when remote debugging via @code{gdbserver}.
> >
> > +When recording an inferior, @value{GDBN} may print additional auxiliary
> > +information during stepping commands and commands displaying the
> execution
> > +history.
> > +
> 
> I wonder why we need this addition.  What is the significance of
> mentioning this factoid in the manual at that place?
> 
> Thanks.

In general this is supposed to note that there might be "new  and therefore
unexpected output" when stepping in a recording. The printing will be active
by default. Since it is recording specific I put it in this place.

Thanks,
Felix

Intel Deutschland GmbH
Registered Address: Am Campeon 10, 85579 Neubiberg, Germany
Tel: +49 89 99 8853-0, www.intel.de <http://www.intel.de>
Managing Directors: Christin Eisenschmid, Sharon Heck, Tiffany Doon Silva  
Chairperson of the Supervisory Board: Nicole Lau
Registered Office: Munich
Commercial Register: Amtsgericht Muenchen HRB 186928

RE: [PATCH v4 06/10] python: Add clear() to gdb.Record.

[Willgerodt, Felix]

> -----Original Message-----
> From: Eli Zaretskii <eliz@gnu.org>
> Sent: Freitag, 6. Mai 2022 13:51
> To: Willgerodt, Felix <felix.willgerodt@intel.com>
> Cc: Metzger, Markus T <markus.t.metzger@intel.com>; gdb-
> patches@sourceware.org
> Subject: Re: [PATCH v4 06/10] python: Add clear() to gdb.Record.
> 
> > Date: Fri,  6 May 2022 13:40:06 +0200
> > From: Felix Willgerodt via Gdb-patches <gdb-patches@sourceware.org>
> >
> > This function allows to clear the trace data from python, forcing to
> > re-decode the trace for successive commands.
> > ---
> >  gdb/doc/python.texi                           |  5 +++++
> >  gdb/python/py-record-btrace.c                 | 13 +++++++++++++
> >  gdb/python/py-record-btrace.h                 |  3 +++
> >  gdb/python/py-record.c                        | 16 ++++++++++++++++
> >  gdb/testsuite/gdb.python/py-record-btrace.exp |  6 +++++-
> >  5 files changed, 42 insertions(+), 1 deletion(-)
> >
> > diff --git a/gdb/doc/python.texi b/gdb/doc/python.texi
> > index 142dbc719a4..707aa5c3ee3 100644
> > --- a/gdb/doc/python.texi
> > +++ b/gdb/doc/python.texi
> > @@ -3779,6 +3779,11 @@ A @code{gdb.Record} object has the following
> methods:
> >  Move the replay position to the given @var{instruction}.
> >  @end defun
> >
> > +@defun Record.clear ()
> > +Clear the trace data of the current recording.  This forces re-decoding of
> the
> > +trace for successive commands.
> > +@end defun
> 
> What does "force re-decoding" mean here? 

The recorded instructions and pt packets will be discarded. "Re-decoding"
means that the pt buffer will be re-read and re-decoded by GDB/libipt
into a new instruction history.

> If this is described in
> another place in the manual, could you add a cross-reference to that
> place?
> 

I don't think it has been described yet, as clear() hasn't directly been exposed
before, only indirectly e.g. via "record stop". The "trace" is however
mentioned e.g. here for "record btrace pt":
https://sourceware.org/gdb/onlinedocs/gdb/Process-Record-and-Replay.html

Should I link that?

Thanks,
Felix






Intel Deutschland GmbH
Registered Address: Am Campeon 10, 85579 Neubiberg, Germany
Tel: +49 89 99 8853-0, www.intel.de <http://www.intel.de>
Managing Directors: Christin Eisenschmid, Sharon Heck, Tiffany Doon Silva  
Chairperson of the Supervisory Board: Nicole Lau
Registered Office: Munich
Commercial Register: Amtsgericht Muenchen HRB 186928

RE: [PATCH v4 07/10] btrace, gdbserver: Add ptwrite to btrace_config_pt.

[Willgerodt, Felix]

> -----Original Message-----
> From: Eli Zaretskii <eliz@gnu.org>
> Sent: Freitag, 6. Mai 2022 13:54
> To: Willgerodt, Felix <felix.willgerodt@intel.com>
> Cc: Metzger, Markus T <markus.t.metzger@intel.com>; gdb-
> patches@sourceware.org
> Subject: Re: [PATCH v4 07/10] btrace, gdbserver: Add ptwrite to
> btrace_config_pt.
> 
> > Date: Fri,  6 May 2022 13:40:07 +0200
> > From: Felix Willgerodt via Gdb-patches <gdb-patches@sourceware.org>
> >
> > +@item Qbtrace-conf:pt:ptwrite=@var{value}
> > +Control recording of ptwrite packets.  This was added for backwards-
> > +compatibility.
> 
> Suggest to rephrase the second sentence to remove "was added".  The
> manual is supposed to describe the current situation, not the history
> (which becomes less and less relevant as time goes by).
> 
> The documentation part is okay with this not fixed.
> 
> Thanks.

I fixed it locally to say "This allows for backwards-compatibility".

Thanks,
Felix
Intel Deutschland GmbH
Registered Address: Am Campeon 10, 85579 Neubiberg, Germany
Tel: +49 89 99 8853-0, www.intel.de <http://www.intel.de>
Managing Directors: Christin Eisenschmid, Sharon Heck, Tiffany Doon Silva  
Chairperson of the Supervisory Board: Nicole Lau
Registered Office: Munich
Commercial Register: Amtsgericht Muenchen HRB 186928

RE: [PATCH v4 10/10] btrace: Extend ptwrite event decoding.

[Willgerodt, Felix]

> -----Original Message-----
> From: Eli Zaretskii <eliz@gnu.org>
> Sent: Freitag, 6. Mai 2022 14:04
> To: Willgerodt, Felix <felix.willgerodt@intel.com>
> Cc: Metzger, Markus T <markus.t.metzger@intel.com>; gdb-
> patches@sourceware.org
> Subject: Re: [PATCH v4 10/10] btrace: Extend ptwrite event decoding.
> 
> > Date: Fri,  6 May 2022 13:40:10 +0200
> > From: Felix Willgerodt via Gdb-patches <gdb-patches@sourceware.org>
> >
> > diff --git a/gdb/NEWS b/gdb/NEWS
> > index a72fee81550..cf807d6209e 100644
> > --- a/gdb/NEWS
> > +++ b/gdb/NEWS
> > @@ -331,6 +331,12 @@ GNU/Linux/OpenRISC		or1k*-*-
> linux*
> >
> >  *** Changes in GDB 11
> >
> > +* GDB now supports printing of ptwrite payloads from the Intel Processor
> > +  Trace during 'record instruction-history', 'record function-call-history',
> > +  all stepping commands and in  Python.  Printing is customizable via a
> > +  ptwrite listener function in  Python.  By default, the raw ptwrite
> > +  payload is printed for each ptwrite that is encountered.
> > +
> 
> This part is OK.
> 
> > +@exdent @value{GDBN} output after recording the sample program in pt
> format:
> > +@smallexample
> > +@group
> > +(gdb) record instruction-history 12,14
> > +12         0x000000000040074c <ptwrite64+16>:	ptwrite %rbx
> > +13         [42]
> > +14         0x0000000000400751 <ptwrite64+21>:	mov    -
> 0x8(%rbp),%rbx
> 
> The last line is too long, and will cause overfull hbox errors when
> producing the printed manual.  Please make it shorter, or break into 2
> lines.
>

I made it shorter. Is there any easy way to figure this out? I don't know what
Is short enough and I couldn't see any  "Overfull \hbox" message for
python.texi in gdb.log or in the output for "make pdf".


> > +@findex gdb.ptwrite.register_listener
> > +@defun register_listener (@var{listener})
> 
> @defun automatically inserts the function into the index, so no need
> for a separate @findex (here and elsewhere in the patch).
> 
> > +Used to register the ptwrite listener.  The listener can be any callable
> > +object that accepts two arguments.
> 
> I think we should describe those 2 arguments, at least shortly.

Will be done in the next revision.


> > +@defun default_listener (@var{payload}, @var{ip})
> > +The listener function active by default.
> 
> Which does what?  If we don't say anything about the default behavior,
> how can a user decide whether to provide his/her specialized listener?
>

Good point. I will describe it in my next revision.
 

> > +@smallexample
> > +@group
> > +(gdb) python-interactive
> > +>>> class my_listener(object):
> > +...    def __init__(self):
> > +...        self.var = 0
> > +...    def __call__(self, payload, ip):
> > +...        if gdb.selected_thread().global_num == 1:
> > +...            self.var += 1
> > +...            return "counter: @{@}, ip: @{:#x@}".format(self.var, ip)
> 
> This last line is too long.
>

Will be shortened as well.


> (And I wonder whether this example really adds something of value to
> what you already described above.)

It is supposed to show how to use it on a per-thread basis. I personally
think the text is giving enough hints without the example and would be
fine to remove it. Yet it was created after a comment from Markus, but
I am not sure if this in its current state still matches his original proposal.


> > +@group
> > +(gdb) info threads
> > +* 1    Thread 0x7ffff7fd8740 (LWP 25796) "ptwrite_threads" task (arg=0x0)
> > +    at bin/ptwrite/ptwrite_threads.c:45
> > +  2    Thread 0x7ffff6eb8700 (LWP 25797) "ptwrite_threads" task (arg=0x0)
> > +    at bin/ptwrite/ptwrite_threads.c:45
> 
> These lines are also too long.
>

Will be shortened as well.

> > +This @value{GDBN} feature is dependent on hardware and operating
> system
> > +support and requires the Intel Processor Trace decoder library in version
> > +2.0.0 or newer.
> 
> You say "hardware and operating system support", but say nothing about
> the OSes on which this can be supported.
>

Any OS can choose to support it at some point. Right now it is Linux only afaik.
But do we want to say that? It might be out-dated at some point.

Thanks,
Felix
Intel Deutschland GmbH
Registered Address: Am Campeon 10, 85579 Neubiberg, Germany
Tel: +49 89 99 8853-0, www.intel.de <http://www.intel.de>
Managing Directors: Christin Eisenschmid, Sharon Heck, Tiffany Doon Silva  
Chairperson of the Supervisory Board: Nicole Lau
Registered Office: Munich
Commercial Register: Amtsgericht Muenchen HRB 186928

Re: [PATCH v4 06/10] python: Add clear() to gdb.Record.

[Eli Zaretskii]

> From: "Willgerodt, Felix" <felix.willgerodt@intel.com>
> CC: "Metzger, Markus T" <markus.t.metzger@intel.com>,
> 	"gdb-patches@sourceware.org" <gdb-patches@sourceware.org>
> Date: Tue, 10 May 2022 13:42:49 +0000
> 
> > > +@defun Record.clear ()
> > > +Clear the trace data of the current recording.  This forces re-decoding of
> > the
> > > +trace for successive commands.
> > > +@end defun
> > 
> > What does "force re-decoding" mean here? 
> 
> The recorded instructions and pt packets will be discarded. "Re-decoding"
> means that the pt buffer will be re-read and re-decoded by GDB/libipt
> into a new instruction history.

Does saying that help users in any way?  If not, maybe just remove
that part?

> > If this is described in
> > another place in the manual, could you add a cross-reference to that
> > place?
> > 
> 
> I don't think it has been described yet, as clear() hasn't directly been exposed
> before, only indirectly e.g. via "record stop". The "trace" is however
> mentioned e.g. here for "record btrace pt":
> https://sourceware.org/gdb/onlinedocs/gdb/Process-Record-and-Replay.html
> 
> Should I link that?

Yes, I think so.

Re: [PATCH v4 10/10] btrace: Extend ptwrite event decoding.

[Eli Zaretskii]

> From: "Willgerodt, Felix" <felix.willgerodt@intel.com>
> CC: "Metzger, Markus T" <markus.t.metzger@intel.com>,
> 	"gdb-patches@sourceware.org" <gdb-patches@sourceware.org>
> Date: Tue, 10 May 2022 13:43:02 +0000
> 
> > The last line is too long, and will cause overfull hbox errors when
> > producing the printed manual.  Please make it shorter, or break into 2
> > lines.
> >
> 
> I made it shorter. Is there any easy way to figure this out? I don't know what
> Is short enough

I think the rule of thumb is that anything longer than 70 characters
in @smallexample should be split.

> and I couldn't see any  "Overfull \hbox" message for
> python.texi in gdb.log or in the output for "make pdf".

I believe that's because we have @finalout in gdb.texinfo.

> > You say "hardware and operating system support", but say nothing about
> > the OSes on which this can be supported.
> >
> 
> Any OS can choose to support it at some point. Right now it is Linux only afaik.
> But do we want to say that? It might be out-dated at some point.

I don't know.  How probable is it that this will be supported on other
systems soon enough?

RE: [PATCH v4 10/10] btrace: Extend ptwrite event decoding.

[Willgerodt, Felix]

> -----Original Message-----
> From: Eli Zaretskii <eliz@gnu.org>
> Sent: Dienstag, 10. Mai 2022 16:12
> To: Willgerodt, Felix <felix.willgerodt@intel.com>
> Cc: Metzger, Markus T <markus.t.metzger@intel.com>; gdb-
> patches@sourceware.org
> Subject: Re: [PATCH v4 10/10] btrace: Extend ptwrite event decoding.
> 
> > From: "Willgerodt, Felix" <felix.willgerodt@intel.com>
> > CC: "Metzger, Markus T" <markus.t.metzger@intel.com>,
> > 	"gdb-patches@sourceware.org" <gdb-patches@sourceware.org>
> > Date: Tue, 10 May 2022 13:43:02 +0000
> >
> > > The last line is too long, and will cause overfull hbox errors when
> > > producing the printed manual.  Please make it shorter, or break into 2
> > > lines.
> > >
> >
> > I made it shorter. Is there any easy way to figure this out? I don't know
> what
> > Is short enough
> 
> I think the rule of thumb is that anything longer than 70 characters
> in @smallexample should be split.
>

Thanks that is good to know!

> > and I couldn't see any  "Overfull \hbox" message for
> > python.texi in gdb.log or in the output for "make pdf".
> 
> I believe that's because we have @finalout in gdb.texinfo.
>

For what it's worth: There are some overfull messages, even
for python.texi. Just not for my changes.

> > > You say "hardware and operating system support", but say nothing about
> > > the OSes on which this can be supported.
> > >
> >
> > Any OS can choose to support it at some point. Right now it is Linux only
> afaik.
> > But do we want to say that? It might be out-dated at some point.
> 
> I don't know.  How probable is it that this will be supported on other
> systems soon enough?

I don't know. Microsoft has added some IPT support for performance
monitoring recently:
https://docs.microsoft.com/en-us/windows-server/virtualization/hyper-v/manage/performance-monitoring-hardware
I am not aware what that means for debuggers. GDB currently doesn't
Support IPT on Windows afaik, but I have never tried it.
But it certainly doesn't seem completely out of the picture for the future.

Thanks,
Felix
Intel Deutschland GmbH
Registered Address: Am Campeon 10, 85579 Neubiberg, Germany
Tel: +49 89 99 8853-0, www.intel.de <http://www.intel.de>
Managing Directors: Christin Eisenschmid, Sharon Heck, Tiffany Doon Silva  
Chairperson of the Supervisory Board: Nicole Lau
Registered Office: Munich
Commercial Register: Amtsgericht Muenchen HRB 186928

RE: [PATCH v4 06/10] python: Add clear() to gdb.Record.

[Willgerodt, Felix]

> -----Original Message-----
> From: Eli Zaretskii <eliz@gnu.org>
> Sent: Dienstag, 10. Mai 2022 16:05
> To: Willgerodt, Felix <felix.willgerodt@intel.com>
> Cc: Metzger, Markus T <markus.t.metzger@intel.com>; gdb-
> patches@sourceware.org
> Subject: Re: [PATCH v4 06/10] python: Add clear() to gdb.Record.
> 
> > From: "Willgerodt, Felix" <felix.willgerodt@intel.com>
> > CC: "Metzger, Markus T" <markus.t.metzger@intel.com>,
> > 	"gdb-patches@sourceware.org" <gdb-patches@sourceware.org>
> > Date: Tue, 10 May 2022 13:42:49 +0000
> >
> > > > +@defun Record.clear ()
> > > > +Clear the trace data of the current recording.  This forces re-decoding
> of
> > > the
> > > > +trace for successive commands.
> > > > +@end defun
> > >
> > > What does "force re-decoding" mean here?
> >
> > The recorded instructions and pt packets will be discarded. "Re-decoding"
> > means that the pt buffer will be re-read and re-decoded by GDB/libipt
> > into a new instruction history.
> 
> Does saying that help users in any way?  If not, maybe just remove
> that part?
> 

It tells the user the actual use case of this command. You will only really use
it if you want GDB to re-decode the trace for your next commands.
Otherwise you would just stop recording.

> > > If this is described in
> > > another place in the manual, could you add a cross-reference to that
> > > place?
> > >
> >
> > I don't think it has been described yet, as clear() hasn't directly been
> exposed
> > before, only indirectly e.g. via "record stop". The "trace" is however
> > mentioned e.g. here for "record btrace pt":
> > https://sourceware.org/gdb/onlinedocs/gdb/Process-Record-and-
> Replay.html
> >
> > Should I link that?
> 
> Yes, I think so.

I added it locally. Then I saw that this chapter at the top, a couple of
lines above already links it. In my eyes this makes the extra link here
redundant. Should I still add it?

Thanks,
Felix
Intel Deutschland GmbH
Registered Address: Am Campeon 10, 85579 Neubiberg, Germany
Tel: +49 89 99 8853-0, www.intel.de <http://www.intel.de>
Managing Directors: Christin Eisenschmid, Sharon Heck, Tiffany Doon Silva  
Chairperson of the Supervisory Board: Nicole Lau
Registered Office: Munich
Commercial Register: Amtsgericht Muenchen HRB 186928

Re: [PATCH v4 06/10] python: Add clear() to gdb.Record.

[Eli Zaretskii]

> From: "Willgerodt, Felix" <felix.willgerodt@intel.com>
> CC: "Metzger, Markus T" <markus.t.metzger@intel.com>,
> 	"gdb-patches@sourceware.org" <gdb-patches@sourceware.org>
> Date: Wed, 11 May 2022 08:22:05 +0000
> 
> > > > If this is described in
> > > > another place in the manual, could you add a cross-reference to that
> > > > place?
> > > >
> > >
> > > I don't think it has been described yet, as clear() hasn't directly been
> > exposed
> > > before, only indirectly e.g. via "record stop". The "trace" is however
> > > mentioned e.g. here for "record btrace pt":
> > > https://sourceware.org/gdb/onlinedocs/gdb/Process-Record-and-
> > Replay.html
> > >
> > > Should I link that?
> > 
> > Yes, I think so.
> 
> I added it locally. Then I saw that this chapter at the top, a couple of
> lines above already links it. In my eyes this makes the extra link here
> redundant. Should I still add it?

No need, thanks.