[RFA v3 03/13] Allow hiding of some filtered frames

Tom Tromey
2018-03-23T20:55:20Z

When a frame filter elides some frames, they are still printed by
"bt", indented a few spaces. PR backtrace/15582 notes that it would
be nice for users if elided frames could simply be dropped. This
patch adds this capability.

gdb/ChangeLog
2018-03-23 Tom Tromey <tom@tromey.com>

PR backtrace/15582:
* stack.c (backtrace_command): Parse "hide" argument.
* python/py-framefilter.c (py_print_frame): Handle PRINT_HIDE.
* extension.h (enum frame_filter_flags) <PRINT_HIDE>: New
constant.

gdb/doc/ChangeLog
2018-03-23 Tom Tromey <tom@tromey.com>

PR backtrace/15582:
* gdb.texinfo (Backtrace): Mention "hide" argument.

gdb/testsuite/ChangeLog
2018-03-23 Tom Tromey <tom@tromey.com>

PR backtrace/15582:
* gdb.python/py-framefilter.exp: Add "bt hide" test.
---
gdb/ChangeLog | 8 +++++
gdb/doc/ChangeLog | 5 +++
gdb/doc/gdb.texinfo | 6 ++++
gdb/extension.h | 3 ++
gdb/python/py-framefilter.c | 50 ++++++++++++++---------------
gdb/stack.c | 2 ++
gdb/testsuite/ChangeLog | 5 +++
gdb/testsuite/gdb.python/py-framefilter.exp | 3 ++
8 files changed, 57 insertions(+), 25 deletions(-)

diff --git a/gdb/doc/gdb.texinfo b/gdb/doc/gdb.texinfo
index b48dd4ed4b..cf9282911a 100644
--- a/gdb/doc/gdb.texinfo
+++ b/gdb/doc/gdb.texinfo
@@ -7337,6 +7337,12 @@ Filter API}, for more information. Additionally use @ref{disable
frame-filter all} to turn off all frame filters. This is only
relevant when @value{GDBN} has been configured with @code{Python}
support.
+
+@item hide
+A Python frame filter might decide to ``elide'' some frames. Normally
+such elided frames are still printed, but they are indented relative
+to the filtered frames that cause them to be elided. The @code{hide}
+option causes elided frames to not be printed at all.
@end table

@kindex where
diff --git a/gdb/extension.h b/gdb/extension.h
index 943792db29..a97292875a 100644
--- a/gdb/extension.h
+++ b/gdb/extension.h
@@ -103,6 +103,9 @@ enum frame_filter_flag

/* Set this flag if a "More frames" message is to be printed. */
PRINT_MORE_FRAMES = 1 << 4,
+
+ /* Set this flag if elided frames should not be printed. */
+ PRINT_HIDE = 1 << 5,
};

DEF_ENUM_FLAGS_TYPE (enum frame_filter_flag, frame_filter_flags);
diff --git a/gdb/python/py-framefilter.c b/gdb/python/py-framefilter.c
index 99d47f247a..aae8d5decf 100644
--- a/gdb/python/py-framefilter.c
+++ b/gdb/python/py-framefilter.c
@@ -1238,37 +1238,37 @@ py_print_frame (PyObject *filter, frame_filter_flags flags,
return EXT_LANG_BT_ERROR;
}

- {
- /* Finally recursively print elided frames, if any. */
- gdbpy_ref<> elided (get_py_iter_from_func (filter, "elided"));
- if (elided == NULL)
- return EXT_LANG_BT_ERROR;
+ if ((flags & PRINT_HIDE) == 0)
+ {
+ /* Finally recursively print elided frames, if any. */
+ gdbpy_ref<> elided (get_py_iter_from_func (filter, "elided"));
+ if (elided == NULL)
+ return EXT_LANG_BT_ERROR;

- if (elided != Py_None)
- {
- PyObject *item;
+ if (elided != Py_None)
+ {
+ PyObject *item;

- ui_out_emit_list inner_list_emiter (out, "children");
+ ui_out_emit_list inner_list_emiter (out, "children");

- if (! out->is_mi_like_p ())
- indent++;
+ if (! out->is_mi_like_p ())
+ indent++;

- while ((item = PyIter_Next (elided.get ())))
- {
- gdbpy_ref<> item_ref (item);
+ while ((item = PyIter_Next (elided.get ())))
+ {
+ gdbpy_ref<> item_ref (item);

- enum ext_lang_bt_status success = py_print_frame (item, flags,
- args_type, out,
- indent,
- levels_printed);
+ enum ext_lang_bt_status success
+ = py_print_frame (item, flags, args_type, out, indent,
+ levels_printed);

- if (success == EXT_LANG_BT_ERROR)
- return EXT_LANG_BT_ERROR;
- }
- if (item == NULL && PyErr_Occurred ())
- return EXT_LANG_BT_ERROR;
- }
- }
+ if (success == EXT_LANG_BT_ERROR)
+ return EXT_LANG_BT_ERROR;
+ }
+ if (item == NULL && PyErr_Occurred ())
+ return EXT_LANG_BT_ERROR;
+ }
+ }

return EXT_LANG_BT_COMPLETED;
}
diff --git a/gdb/stack.c b/gdb/stack.c
index 76695ff7e6..8e8fe12109 100644
--- a/gdb/stack.c
+++ b/gdb/stack.c
@@ -1867,6 +1867,8 @@ backtrace_command (const char *arg, int from_tty)
filters = false;
else if (subset_compare (this_arg.c_str (), "full"))
flags |= PRINT_LOCALS;
+ else if (subset_compare (this_arg.c_str (), "hide"))
+ flags |= PRINT_HIDE;
else
{
/* Not a recognized argument, so stop. */
diff --git a/gdb/testsuite/gdb.python/py-framefilter.exp b/gdb/testsuite/gdb.python/py-framefilter.exp
index 7e02e9d701..cc31dd5893 100644
--- a/gdb/testsuite/gdb.python/py-framefilter.exp
+++ b/gdb/testsuite/gdb.python/py-framefilter.exp
@@ -157,6 +157,9 @@ gdb_test "bt no-filter full" \
gdb_test "bt full" \
".*#0.*end_func.*str = $hex \"The End\".*st2 = $hex \"Is Near\".*b = 12.*c = 5.*#1.*in funca \\(\\).*#2.*in funcb \\(j=10\\).*bar = \{a = 42, b = 84\}.*#22.*in func1 \\(\\).*#23.*in func2 \\(f=3\\).*elided = $hex \"Elided frame\".*fb = \{nothing = $hex \"Elided Foo Bar\", f = 84, s = 38\}.*bf = $hex.*" \
"bt full with Reverse disabled"
+gdb_test "bt full hide" \
+ ".*#0.*end_func.*str = $hex \"The End\".*st2 = $hex \"Is Near\".*b = 12.*c = 5.*#1.*in funca \\(\\).*#2.*in funcb \\(j=10\\).*bar = \{a = 42, b = 84\}.*#22.*in func1 \\(\\)\[^#\]*#24.*in func3 \\(i=3\\).*" \
+ "bt full hide with Reverse disabled"

# Test set print frame-arguments
# none
--
2.13.6