Special case NULL when using printf's %s format

This changes the printf command's %s and %ls formats to special-case
NULL, and print "(null)" for these.  This is PR cli/14977.  This
behavior seems a bit friendlier; I was undecided on whether other
invalid pointers should be handled specially somehow, so for the time
being I've left those out.

gdb/ChangeLog
2018-03-14  Tom Tromey  <tom@tromey.com>

	PR cli/14977:
	* printcmd.c (printf_c_string, printf_wide_c_string): Special case
	for NULL.

gdb/gdbserver/ChangeLog
2018-03-14  Tom Tromey  <tom@tromey.com>

	PR cli/14977:
	* ax.c (ax_printf): Special case for NULL.

gdb/testsuite/ChangeLog
2018-03-14  Tom Tromey  <tom@tromey.com>

	PR cli/14977:
	* gdb.base/printcmds.exp (test_printf): Add printf test of %s with
	a null pointer.
	* gdb.base/wchar.exp: Likewise.
This commit is contained in:
Tom Tromey
2018-02-14 20:11:16 -07:00
parent b8c2339b2f
commit 3ae9ce5dd7
7 changed files with 39 additions and 0 deletions

View File

@ -1,3 +1,9 @@
2018-03-14 Tom Tromey <tom@tromey.com>
PR cli/14977:
* printcmd.c (printf_c_string, printf_wide_c_string): Special case
for NULL.
2018-03-14 Tom Tromey <tom@tromey.com>
PR cli/19918:

View File

@ -1,3 +1,8 @@
2018-03-14 Tom Tromey <tom@tromey.com>
PR cli/14977:
* ax.c (ax_printf): Special case for NULL.
2018-03-08 Simon Marchi <simon.marchi@polymtl.ca>
* linux-low.c (linux_qxfer_libraries_svr4): Use

View File

@ -847,6 +847,11 @@ ax_printf (CORE_ADDR fn, CORE_ADDR chan, const char *format,
int j;
tem = args[i];
if (tem == 0)
{
printf (current_substring, "(null)");
break;
}
/* This is a %s argument. Find the length of the string. */
for (j = 0;; j++)

View File

@ -2220,6 +2220,11 @@ printf_c_string (struct ui_file *stream, const char *format,
int j;
tem = value_as_address (value);
if (tem == 0)
{
fprintf_filtered (stream, format, "(null)");
return;
}
/* This is a %s argument. Find the length of the string. */
for (j = 0;; j++)
@ -2260,6 +2265,11 @@ printf_wide_c_string (struct ui_file *stream, const char *format,
gdb_byte *buf = (gdb_byte *) alloca (wcwidth);
tem = value_as_address (value);
if (tem == 0)
{
fprintf_filtered (stream, format, "(null)");
return;
}
/* This is a %s argument. Find the length of the string. */
for (j = 0;; j += wcwidth)

View File

@ -1,3 +1,10 @@
2018-03-14 Tom Tromey <tom@tromey.com>
PR cli/14977:
* gdb.base/printcmds.exp (test_printf): Add printf test of %s with
a null pointer.
* gdb.base/wchar.exp: Likewise.
2018-03-14 Tom Tromey <tom@tromey.com>
PR cli/19918:

View File

@ -780,6 +780,9 @@ proc test_printf {} {
# PR cli/19918.
gdb_test "printf \"%-16dq\\n\", 0" "0 q"
gdb_test "printf \"%-16pq\\n\", 0" "\\(nil\\) q"
# PR cli/14977.
gdb_test "printf \"%s\\n\", 0" "\\(null\\)"
}
#Test printing DFP values with printf

View File

@ -69,3 +69,6 @@ gdb_test "print repeat" "= L\"A$cent$cent\"\.\.\." \
gdb_test "print repeat_p" "= $hex L\"A$cent$cent\"\.\.\." \
"print repeat_p (print elements 3)"
# From PR cli/14977, but here because it requires wchar_t.
gdb_test "printf \"%ls\\n\", 0" "\\(null\\)"