From: Bruno Larsen <blarsen@redhat.com>
To: gdb-patches@sourceware.org
Cc: Bruno Larsen <blarsen@redhat.com>
Subject: [PATCH v4 3/4] gdb/cli: Improve UX when using list with no args
Date: Thu, 13 Jul 2023 12:24:10 +0200 [thread overview]
Message-ID: <20230713102411.2279542-4-blarsen@redhat.com> (raw)
In-Reply-To: <20230713102411.2279542-1-blarsen@redhat.com>
When using "list" with no arguments, GDB will first print the lines
around where the inferior is stopped, then print the next N lines until
reaching the end of file, at which point it wanrs the user "Line X out
of range, file Y only has X-1 lines.". This is usually desireable, but
if the user can no longer see the original line, they may have forgotten
the current line or that a list command was used at all, making GDB's
error message look cryptic. It was reported in bugzilla as PR cli/30497.
This commit improves the user experince by changing the behavior of
"list" slightly when a user passes no arguments. It now prints that the
end of the file has been reached and recommends that the user use the
command "list ." instead.
Bug: https://sourceware.org/bugzilla/show_bug.cgi?id=30497
---
gdb/NEWS | 5 +++++
gdb/cli/cli-cmds.c | 17 +++++++++++++----
gdb/doc/gdb.texinfo | 4 +++-
gdb/source.c | 16 ++++++++++++++++
gdb/source.h | 7 +++++++
gdb/testsuite/gdb.base/list.exp | 8 ++++----
6 files changed, 48 insertions(+), 9 deletions(-)
diff --git a/gdb/NEWS b/gdb/NEWS
index eef440a5242..df26606c9a8 100644
--- a/gdb/NEWS
+++ b/gdb/NEWS
@@ -88,6 +88,11 @@
print the location where the inferior is stopped. If the inferior hasn't
started yet, the command will print around the main function.
+* Using the 'list' command with no arguments in a situation where the
+ command would attempt to list past the end of the file now warns the
+ user that the end of file has been reached, refers the user to the
+ newly added '.' argument
+
* New commands
maintenance print record-instruction [ N ]
diff --git a/gdb/cli/cli-cmds.c b/gdb/cli/cli-cmds.c
index 1c459afdc97..5f5933e7963 100644
--- a/gdb/cli/cli-cmds.c
+++ b/gdb/cli/cli-cmds.c
@@ -1246,10 +1246,19 @@ list_command (const char *arg, int from_tty)
list_around_line (arg, cursal);
}
- /* "l" or "l +" lists next ten lines. */
- else if (arg == NULL || arg[0] == '+')
- print_source_lines (cursal.symtab,
- source_lines_range (cursal.line), 0);
+ /* "l" and "l +" lists the next few lines, unless we're listing past
+ the end of the file. */
+ else if (arg == nullptr || arg[0] == '+')
+ {
+ if (last_symtab_line (cursal.symtab) >= cursal.line)
+ print_source_lines (cursal.symtab,
+ source_lines_range (cursal.line), 0);
+ else
+ {
+ error (_("End of the file was already reached, use \"list .\" to"
+ " list the current location again"));
+ }
+ }
/* "l -" lists previous ten lines, the ones before the ten just
listed. */
diff --git a/gdb/doc/gdb.texinfo b/gdb/doc/gdb.texinfo
index 7619efe3de9..20c9b24400d 100644
--- a/gdb/doc/gdb.texinfo
+++ b/gdb/doc/gdb.texinfo
@@ -9144,7 +9144,9 @@ Print more lines. If the last lines printed were printed with a
@code{list} command, this prints lines following the last lines
printed; however, if the last line printed was a solitary line printed
as part of displaying a stack frame (@pxref{Stack, ,Examining the
-Stack}), this prints lines centered around that line.
+Stack}), this prints lines centered around that line. If no
+@code{list} command has been used and no solitary line was printed,
+it prints the lines around the function @code{main}.
@item list -
Print lines just before the lines last printed.
diff --git a/gdb/source.c b/gdb/source.c
index 9997cccb31b..08adc6671b7 100644
--- a/gdb/source.c
+++ b/gdb/source.c
@@ -1484,6 +1484,22 @@ print_source_lines (struct symtab *s, source_lines_range line_range,
line_range.stopline (), flags);
}
+/* See source.h. */
+
+int
+last_symtab_line (struct symtab *s)
+{
+ const std::vector<off_t> *offsets;
+
+ /* Try to get the offsets for the start of each line. */
+ if (!g_source_cache.get_line_charpos (s, &offsets))
+ return false;
+ if (offsets == nullptr)
+ return false;
+
+ return offsets->size ();
+}
+
\f
/* Print info on range of pc's in a specified line. */
diff --git a/gdb/source.h b/gdb/source.h
index 8fbc365680d..be80e003890 100644
--- a/gdb/source.h
+++ b/gdb/source.h
@@ -192,6 +192,13 @@ class source_lines_range
int m_stopline;
};
+/* Get the number of the last line in the given symtab. */
+extern int last_symtab_line (struct symtab *s);
+
+/* Check if the line LINE can be found in the symtab S, so that it can be
+ printed. */
+extern bool can_print_line (struct symtab *s, int line);
+
/* Variation of previous print_source_lines that takes a range instead of a
start and end line number. */
extern void print_source_lines (struct symtab *s, source_lines_range r,
diff --git a/gdb/testsuite/gdb.base/list.exp b/gdb/testsuite/gdb.base/list.exp
index ed178a1dd95..582355996b0 100644
--- a/gdb/testsuite/gdb.base/list.exp
+++ b/gdb/testsuite/gdb.base/list.exp
@@ -175,8 +175,8 @@ proc_with_prefix test_list_forward {} {
"list 25-34"
gdb_test "list" "35\[ \t\]+foo \\(.*\\);.*${last_line_re}" \
"list 35-42"
- gdb_test "list" "Line number 44 out of range; \[^\r\n\]+ has 43 lines\." \
- "end of file error after \"list\" command"
+ gdb_test "list" "End of the file was already reached, use \"list .\" to list the current location again" \
+ "list past end of file"
}
# Test that repeating the list linenum command doesn't print the same
@@ -194,8 +194,8 @@ proc_with_prefix test_repeat_list_command {} {
"list 25-34"
gdb_test " " "35\[ \t\]+foo \\(.*\\);.*${last_line_re}" \
"list 35-42"
- gdb_test "list" "Line number 44 out of range; \[^\r\n\]+ has 43 lines\." \
- "end of file error after using 'return' to repeat the list command"
+ gdb_test "list" "End of the file was already reached, use \"list .\" to list the current location again" \
+ "list past end of file"
}
proc_with_prefix test_list_backwards {} {
--
2.41.0
next prev parent reply other threads:[~2023-07-13 10:24 UTC|newest]
Thread overview: 37+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-07-13 10:24 [PATCH v4 0/4] Small changes to "list" command Bruno Larsen
2023-07-13 10:24 ` [PATCH v4 1/4] gdb/cli: Factor out code to list lines around a given line Bruno Larsen
2023-07-13 16:53 ` Tom Tromey
2023-07-13 10:24 ` [PATCH v4 2/4] gdb/cli: add '.' as an argument for 'list' command Bruno Larsen
2023-07-13 11:05 ` Eli Zaretskii
2023-07-13 16:53 ` Tom Tromey
2023-07-14 17:50 ` Pedro Alves
2023-07-17 8:21 ` Bruno Larsen
2023-07-17 8:44 ` Andrew Burgess
2023-07-17 14:14 ` Pedro Alves
2023-07-18 11:21 ` [PATCH] gdb/cli: fixes to newly added "list ." command Bruno Larsen
2023-07-18 12:54 ` Eli Zaretskii
2023-07-18 13:40 ` Bruno Larsen
2023-07-18 16:17 ` Eli Zaretskii
2023-07-18 13:43 ` Pedro Alves
2023-07-18 14:55 ` Bruno Larsen
2023-07-21 10:26 ` [PATCH v2] " Bruno Larsen
2023-07-21 11:05 ` Eli Zaretskii
2023-08-04 8:37 ` [PING][PATCH " Bruno Larsen
2023-08-23 10:03 ` [PINGv2][PATCH " Guinevere Larsen
2023-08-23 15:00 ` [PATCH " Andrew Burgess
2023-08-28 15:50 ` [PATCH v3] " Guinevere Larsen
2023-09-14 13:00 ` [PING][PATCH " Guinevere Larsen
2023-09-18 13:16 ` [PATCH " Andrew Burgess
2023-09-19 9:06 ` [PATCH v4] " Guinevere Larsen
2023-09-19 11:27 ` Eli Zaretskii
2023-09-19 12:07 ` Guinevere Larsen
2023-07-13 10:24 ` Bruno Larsen [this message]
2023-07-13 11:06 ` [PATCH v4 3/4] gdb/cli: Improve UX when using list with no args Eli Zaretskii
2023-07-13 17:41 ` Keith Seitz
2023-07-13 10:24 ` [PATCH v4 4/4] gdb/doc: document '+' argument for 'list' command Bruno Larsen
2023-07-13 17:35 ` Keith Seitz
2023-07-13 21:30 ` Matt Rice
2023-07-14 8:53 ` Bruno Larsen
2023-07-14 16:30 ` Tom Tromey
2023-07-14 21:30 ` Matt Rice
2023-07-13 17:31 ` [PATCH v4 0/4] Small changes to "list" command Tom Tromey
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