From: Keith Seitz <keiths@redhat.com>
To: gdb-patches@sourceware.org
Subject: [PATCH] Allow strings with printf/eval
Date: Sun, 23 Apr 2023 10:21:31 -0700 [thread overview]
Message-ID: <20230423172131.1104908-1-keiths@redhat.com> (raw)
If a user attempts to use a string with either `printf' or `eval'
commands, gdb returns an error (inferior not running):
(gdb) printf "%s\n", "hello"
evaluation of this expression requires the target program to be active
However, the parser can certainly handle this case:
(gdb) p "hello"
$1 = "hello"
This discrepancy occurs because printf_c_string does not handle
this specific case. The passed-in value that we are attempting to print
as a string is TYPE_CODE_ARRAY but it's lval type is not_lval.
printf_c_string will only attempt to print a string from the value's
contents when !TYPE_CODE_PTR, lval is lval_internalvar, and the value's
type is considered a string type:
if (value->type ()->code () != TYPE_CODE_PTR
&& value->lval () == lval_internalvar
&& c_is_string_type_p (value->type ()))
{
...
}
Otherwise, it attempts to read the value of the string from the target's
memory (which is what actually generates the "evaluation of this ..."
error message).
---
gdb/printcmd.c | 4 ++--
gdb/testsuite/gdb.base/eval.exp | 16 ++++++++++++++++
gdb/testsuite/gdb.base/printcmds.exp | 25 +++++++++++++++++++++++++
3 files changed, 43 insertions(+), 2 deletions(-)
diff --git a/gdb/printcmd.c b/gdb/printcmd.c
index dd92e31d31b..7eb28da5e24 100644
--- a/gdb/printcmd.c
+++ b/gdb/printcmd.c
@@ -2447,8 +2447,8 @@ printf_c_string (struct ui_file *stream, const char *format,
{
const gdb_byte *str;
- if (value->type ()->code () != TYPE_CODE_PTR
- && value->lval () == lval_internalvar
+ if (((value->type ()->code () != TYPE_CODE_PTR && value->lval () == lval_internalvar)
+ || (value->type ()->code () == TYPE_CODE_ARRAY && value->lval () == not_lval))
&& c_is_string_type_p (value->type ()))
{
size_t len = value->type ()->length ();
diff --git a/gdb/testsuite/gdb.base/eval.exp b/gdb/testsuite/gdb.base/eval.exp
index ead053ca712..8a31c9ea944 100644
--- a/gdb/testsuite/gdb.base/eval.exp
+++ b/gdb/testsuite/gdb.base/eval.exp
@@ -20,3 +20,19 @@ gdb_test_no_output "set \$a = 10" "initialize \$a."
gdb_test "eval \"echo %d\\n\", \$a++" "10" "first eval."
gdb_test "eval \"echo %d\\n\", \$a*2" "22" "second eval."
+
+gdb_test_no_output "set var \$hi = \"Hi\""
+gdb_test {eval "echo %s, %s%c\n", $hi, "mom", '!'} "Hi, mom!"
+
+set listsize_value -1
+gdb_test_multiple "show listsize" "get listsize value" {
+ -re "Number of source lines gdb will list by default is (\[0-9\]+)\.\r\n$gdb_prompt $" {
+ set listsize_value $expect_out(1,string)
+ }
+}
+
+if {$listsize_value > -1} {
+ gdb_test {eval "echo %s\n", $_gdb_setting_str("listsize")} $listsize_value
+} else {
+ send_log "warning: could not get listsize\n"
+}
diff --git a/gdb/testsuite/gdb.base/printcmds.exp b/gdb/testsuite/gdb.base/printcmds.exp
index 21a2cad458c..db57769c303 100644
--- a/gdb/testsuite/gdb.base/printcmds.exp
+++ b/gdb/testsuite/gdb.base/printcmds.exp
@@ -957,6 +957,30 @@ proc test_printf_with_dfp {} {
gdb_test "printf \"%Hf %Hf\\n\",1.2df,1.3df" "1.2 1.3"
}
+# Test printf with strings.
+proc test_printf_with_strings {} {
+ global gdb_prompt
+
+ gdb_test {printf "I ate a %s yesterday; it was very %s!\n", "clock", "time-consuming"} \
+ "I ate a clock yesterday; it was very time-consuming!"
+ gdb_test_no_output "set var \$hello = \"Hello\""
+
+ gdb_test {printf "%s, %s%c\n", $hello, "world", '!'} "Hello, world!"
+
+ set listsize_value -1
+ gdb_test_multiple "show listsize" "get listsize value" {
+ -re "Number of source lines gdb will list by default is (\[0-9\]+)\.\r\n$gdb_prompt $" {
+ set listsize_value $expect_out(1,string)
+ }
+ }
+
+ if {$listsize_value > -1} {
+ gdb_test {printf "%s\n", $_gdb_setting_str("listsize")} $listsize_value
+ } else {
+ send_log "warning: could not get listsize\n"
+ }
+}
+
proc test_print_symbol {} {
gdb_test_no_output "set print symbol on"
@@ -1171,6 +1195,7 @@ test_print_array_constants
test_print_enums
test_printf
test_printf_with_dfp
+test_printf_with_strings
test_print_symbol
test_repeat_bytes
test_radices
--
2.39.2
next reply other threads:[~2023-04-23 17:21 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-04-23 17:21 Keith Seitz [this message]
2023-04-24 17:12 ` Tom Tromey
2023-04-25 15:50 ` Keith Seitz
2023-04-25 20:21 ` Tom Tromey
2023-04-28 17:45 ` Keith Seitz
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