diff mbox series

[1/2] Export "finish" return value to Python

Message ID 20240212-dap-finish-v1-1-8e30870e8b25@adacore.com
State New
Headers
Series Add "finish" return value to DAP |

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Commit Message

Tom Tromey Feb. 12, 2024, 6:47 p.m. UTC 
  This patch changes the Python "stop" event emission code to also add
the function return value, if it is known.  This happens when the stop
comes from a "finish" command and when the value can be fetched.

The test is in the next patch.
---
 gdb/doc/python.texi       |  6 ++++++
 gdb/infcmd.c              | 17 -----------------
 gdb/python/py-stopevent.c | 23 ++++++++++++++++++++++-
 gdb/thread-fsm.h          | 19 +++++++++++++++++++
 4 files changed, 47 insertions(+), 18 deletions(-)

Comments

Eli Zaretskii Feb. 12, 2024, 7:24 p.m. UTC | #1 
> From: Tom Tromey <tromey@adacore.com>
> Date: Mon, 12 Feb 2024 11:47:02 -0700
> 
> This patch changes the Python "stop" event emission code to also add
> the function return value, if it is known.  This happens when the stop
> comes from a "finish" command and when the value can be fetched.
> 
> The test is in the next patch.
> ---
>  gdb/doc/python.texi       |  6 ++++++
>  gdb/infcmd.c              | 17 -----------------
>  gdb/python/py-stopevent.c | 23 ++++++++++++++++++++++-
>  gdb/thread-fsm.h          | 19 +++++++++++++++++++
>  4 files changed, 47 insertions(+), 18 deletions(-)

Thanks, the documentation part is okay.

Reviewed-By: Eli Zaretskii <eliz@gnu.org>
diff mbox series

Patch

diff --git a/gdb/doc/python.texi b/gdb/doc/python.texi
index ece9038844c..21a84fabb34 100644
--- a/gdb/doc/python.texi
+++ b/gdb/doc/python.texi
@@ -3813,6 +3813,12 @@  corresponding MI output (@pxref{GDB/MI Async Records}).
 
 A dictionary was used for this (rather than adding attributes directly
 to the event object) so that the MI keys could be used unchanged.
+
+When a @code{StopEvent} results from a @code{finish} command, it will
+also hold the return value from the function, if that is available.
+This will be an entry named @samp{return-value} in the @code{details}
+dictionary.  The value of this entry will be a @code{gdb.Value}
+object.
 @end defvar
 
 Emits @code{gdb.SignalEvent}, which extends @code{gdb.StopEvent}.
diff --git a/gdb/infcmd.c b/gdb/infcmd.c
index 4e17a6b0629..68f64f0d2b3 100644
--- a/gdb/infcmd.c
+++ b/gdb/infcmd.c
@@ -1484,23 +1484,6 @@  get_return_value (struct symbol *func_symbol, struct value *function)
   return value;
 }
 
-/* The captured function return value/type and its position in the
-   value history.  */
-
-struct return_value_info
-{
-  /* The captured return value.  May be NULL if we weren't able to
-     retrieve it.  See get_return_value.  */
-  struct value *value;
-
-  /* The return type.  In some cases, we'll not be able extract the
-     return value, but we always know the type.  */
-  struct type *type;
-
-  /* If we captured a value, this is the value history index.  */
-  int value_history_index;
-};
-
 /* Helper for print_return_value.  */
 
 static void
diff --git a/gdb/python/py-stopevent.c b/gdb/python/py-stopevent.c
index 61d93727b31..fcaebe26f13 100644
--- a/gdb/python/py-stopevent.c
+++ b/gdb/python/py-stopevent.c
@@ -20,6 +20,7 @@ 
 #include "defs.h"
 #include "py-stopevent.h"
 #include "py-uiout.h"
+#include "thread-fsm.h"
 
 gdbpy_ref<>
 create_stop_event_object (PyTypeObject *py_type, const gdbpy_ref<> &dict)
@@ -45,6 +46,7 @@  static gdbpy_ref<>
 py_print_bpstat (bpstat *bs, enum gdb_signal stop_signal)
 {
   py_ui_out uiout;
+  struct value *return_value = nullptr;
 
   try
     {
@@ -55,6 +57,10 @@  py_print_bpstat (bpstat *bs, enum gdb_signal stop_signal)
 	{
 	  async_reply_reason reason = tp->thread_fsm ()->async_reply_reason ();
 	  uiout.field_string ("reason", async_reason_lookup (reason));
+
+	  return_value_info *rvinfo = tp->thread_fsm ()->return_value ();
+	  if (rvinfo != nullptr && rvinfo->value != nullptr)
+	    return_value = rvinfo->value;
 	}
 
       if (stop_signal != GDB_SIGNAL_0 && stop_signal != GDB_SIGNAL_TRAP)
@@ -73,7 +79,22 @@  py_print_bpstat (bpstat *bs, enum gdb_signal stop_signal)
       return nullptr;
     }
 
-  return uiout.result ();
+  gdbpy_ref<> dict = uiout.result ();
+  if (dict == nullptr)
+    return nullptr;
+
+  /* This has to be done separately to avoid error issues, and because
+     there's no API to add generic Python objects to a py_ui_out.  */
+  if (return_value != nullptr)
+    {
+      gdbpy_ref<> val (value_to_value_object (return_value));
+      if (val == nullptr)
+	return nullptr;
+      if (PyDict_SetItemString (dict.get (), "finish-value", val.get ()) < 0)
+	return nullptr;
+    }
+
+  return dict;
 }
 
 /* Callback observers when a stop event occurs.  This function will create a
diff --git a/gdb/thread-fsm.h b/gdb/thread-fsm.h
index 90abb5c27f6..ed117719c0d 100644
--- a/gdb/thread-fsm.h
+++ b/gdb/thread-fsm.h
@@ -23,6 +23,25 @@ 
 
 struct return_value_info;
 struct thread_fsm_ops;
+struct type;
+struct value;
+
+/* The captured function return value/type and its position in the
+   value history.  */
+
+struct return_value_info
+{
+  /* The captured return value.  May be NULL if we weren't able to
+     retrieve it.  See get_return_value.  */
+  struct value *value;
+
+  /* The return type.  In some cases, we'll not be able extract the
+     return value, but we always know the type.  */
+  struct type *type;
+
+  /* If we captured a value, this is the value history index.  */
+  int value_history_index;
+};
 
 /* A thread finite-state machine structure contains the necessary info
    and callbacks to manage the state machine protocol of a thread's