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[RFA] Make "bt N" print correct number of frames when using a frame filter
- From: Tom Tromey <tom at tromey dot com>
- To: gdb-patches at sourceware dot org
- Cc: Tom Tromey <tom at tromey dot com>
- Date: Sun, 23 Apr 2017 10:04:46 -0600
- Subject: [RFA] Make "bt N" print correct number of frames when using a frame filter
- Authentication-results: sourceware.org; auth=none
PR python/16497 notes that using "bt" with a positive argument prints
the wrong number of frames when a frame filter is in use. Also, in this
case, the non-frame-filter path will print a message about "More stack
frames" when there are more; but this is not done in the frame-filter
case.
The first problem is that backtrace_command_1 passes the wrong value
to apply_ext_lang_frame_filter -- that function takes the final
frame's number as an argument, but backtrace_command_1 passes the
count, which is off by one.
The solution to the second problem is to have the C stack-printing
code stop at the correct number of frames and then print the message.
Tested using the buildbot.
ChangeLog
2017-04-22 Tom Tromey <tom@tromey.com>
PR python/16497:
* stack.c (backtrace_command_1): Set PRINT_MORE_FRAMES flag. Fix
off-by-one in py_end computation.
* python/py-framefilter.c (gdbpy_apply_frame_filter): Handle
PRINT_MORE_FRAMES.
* extension.h (enum frame_filter_flags) <PRINT_MORE_FRAMES>: New
constant.
testsuite/ChangeLog
2017-04-22 Tom Tromey <tom@tromey.com>
PR python/16497:
* gdb.python/py-framefilter.exp: Update test.
---
gdb/ChangeLog | 10 ++++++++++
gdb/extension.h | 3 +++
gdb/python/py-framefilter.c | 25 +++++++++++++++++++++++++
gdb/stack.c | 6 +++++-
gdb/testsuite/ChangeLog | 5 +++++
gdb/testsuite/gdb.python/py-framefilter.exp | 2 +-
6 files changed, 49 insertions(+), 2 deletions(-)
diff --git a/gdb/ChangeLog b/gdb/ChangeLog
index 28ae0a7..85d5da5 100644
--- a/gdb/ChangeLog
+++ b/gdb/ChangeLog
@@ -1,5 +1,15 @@
2017-04-22 Tom Tromey <tom@tromey.com>
+ PR python/16497:
+ * stack.c (backtrace_command_1): Set PRINT_MORE_FRAMES flag. Fix
+ off-by-one in py_end computation.
+ * python/py-framefilter.c (gdbpy_apply_frame_filter): Handle
+ PRINT_MORE_FRAMES.
+ * extension.h (enum frame_filter_flags) <PRINT_MORE_FRAMES>: New
+ constant.
+
+2017-04-22 Tom Tromey <tom@tromey.com>
+
* mi/mi-cmd-file.c (mi_cmd_file_list_shared_libraries): Use
ui_out_emit_list.
* stack.c (print_frame): Use ui_out_emit_list.
diff --git a/gdb/extension.h b/gdb/extension.h
index 2c79411..cda2ebf 100644
--- a/gdb/extension.h
+++ b/gdb/extension.h
@@ -100,6 +100,9 @@ enum frame_filter_flags
/* Set this flag if frame locals are to be printed. */
PRINT_LOCALS = 8,
+
+ /* Set this flag if a "More frames" message is to be printed. */
+ PRINT_MORE_FRAMES = 16,
};
/* A choice of the different frame argument printing strategies that
diff --git a/gdb/python/py-framefilter.c b/gdb/python/py-framefilter.c
index 75b055c..b604d51 100644
--- a/gdb/python/py-framefilter.c
+++ b/gdb/python/py-framefilter.c
@@ -1355,6 +1355,18 @@ gdbpy_apply_frame_filter (const struct extension_language_defn *extlang,
gdbpy_enter enter_py (gdbarch, current_language);
+ /* When we're limiting the number of frames, be careful to request
+ one extra frame, so that we can print a message if there are more
+ frames. */
+ int frame_countdown = -1;
+ if ((flags & PRINT_MORE_FRAMES) != 0 && frame_low >= 0 && frame_high >= 0)
+ {
+ ++frame_high;
+ /* This has an extra +1 because it is checked before a frame is
+ printed. */
+ frame_countdown = frame_high - frame_low + 1;
+ }
+
gdbpy_ref<> iterable (bootstrap_python_frame_filters (frame, frame_low,
frame_high));
@@ -1402,6 +1414,19 @@ gdbpy_apply_frame_filter (const struct extension_language_defn *extlang,
break;
}
+ if (frame_countdown != -1)
+ {
+ assert ((flags & PRINT_MORE_FRAMES) != 0);
+ --frame_countdown;
+ if (frame_countdown == 0)
+ {
+ /* We've printed all the frames we were asked to
+ print, but more frames existed. */
+ printf_filtered (_("(More stack frames follow...)\n"));
+ break;
+ }
+ }
+
success = py_print_frame (item.get (), flags, args_type, out, 0,
levels_printed.get ());
diff --git a/gdb/stack.c b/gdb/stack.c
index 7f8a51c..37e8767 100644
--- a/gdb/stack.c
+++ b/gdb/stack.c
@@ -1766,7 +1766,9 @@ backtrace_command_1 (char *count_exp, int show_locals, int no_filters,
else
{
py_start = 0;
- py_end = count;
+ /* The argument to apply_ext_lang_frame_filter is the number
+ of the final frame to print, and frames start at 0. */
+ py_end = count - 1;
}
}
else
@@ -1800,6 +1802,8 @@ backtrace_command_1 (char *count_exp, int show_locals, int no_filters,
if (show_locals)
flags |= PRINT_LOCALS;
+ if (from_tty)
+ flags |= PRINT_MORE_FRAMES;
if (!strcmp (print_frame_arguments, "scalars"))
arg_type = CLI_SCALAR_VALUES;
diff --git a/gdb/testsuite/ChangeLog b/gdb/testsuite/ChangeLog
index c4d5b79..df883da 100644
--- a/gdb/testsuite/ChangeLog
+++ b/gdb/testsuite/ChangeLog
@@ -1,3 +1,8 @@
+2017-04-22 Tom Tromey <tom@tromey.com>
+
+ PR python/16497:
+ * gdb.python/py-framefilter.exp: Update test.
+
2017-04-19 Pedro Alves <palves@redhat.com>
* gdb.threads/threadapply.exp (kill_and_remove_inferior): New
diff --git a/gdb/testsuite/gdb.python/py-framefilter.exp b/gdb/testsuite/gdb.python/py-framefilter.exp
index bbec48d..d81d144 100644
--- a/gdb/testsuite/gdb.python/py-framefilter.exp
+++ b/gdb/testsuite/gdb.python/py-framefilter.exp
@@ -149,7 +149,7 @@ gdb_test "bt -2" \
".*#26.*func5.*#27.*in main \\(\\).*" \
"bt -2 with frame-filter Reverse disabled"
gdb_test "bt 3" \
- ".*#0.*end_func.*#1.*in funca \\(\\).*#2.*in funcb \\(j=10\\).*" \
+ ".*#0.*end_func.*#1.*in funca \\(\\).*#2.*in funcb \\(j=10\\)\[^#\]*More stack frames follow.*" \
"bt 3 with frame-filter Reverse disabled"
gdb_test "bt no-filter 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\}.*" \
--
2.9.3