[gdb/testsuite] Fix gdb.base/style.exp with -m32

When running test-case gdb.base/style.exp with target board unix/-m32, we run
into (stripped styling from output, shortened file name):
...
(gdb) frame
    argv=0xffffc714) at src/gdb/testsuite/gdb.base/style.c:45
45        return some_called_function (); /* break here */
(gdb) FAIL: gdb.base/style.exp: frame when width=20
...
while with native we have instead:
...
(gdb) frame
    argv=0x7fffffffd478)
    at src/gdb/testsuite/gdb.base/style.c:45
45        return some_called_function (); /* break here */
(gdb) PASS: gdb.base/style.exp: frame when width=20
...

The problem is that due to argv having a different length for -m32, we get a
different layout, and the test-case doesn't accommodate for that.

Fix this by using a different regexp depending on the length of argv.

Tested on x86_64-linux.

gdb/testsuite/ChangeLog:

2021-01-14  Tom de Vries  <tdevries@suse.de>

	PR testsuite/24590
	* gdb.base/style.exp: Handle shorter argv in frame command output.

2 files changed, 48 insertions, 6 deletions

diff --git a/gdb/testsuite/ChangeLog b/gdb/testsuite/ChangeLog
index cfc49db..b8c9010 100644
--- a/gdb/testsuite/ChangeLog
+++ b/gdb/testsuite/ChangeLog
@@ -1,3 +1,8 @@
+2021-01-14  Tom de Vries  <tdevries@suse.de>
+
+	PR testsuite/24590
+	* gdb.base/style.exp: Handle shorter argv in frame command output.
+
 2021-01-13  Andrew Burgess  <andrew.burgess@embecosm.com>
 
 	PR gdb/26819
diff --git a/gdb/testsuite/gdb.base/style.exp b/gdb/testsuite/gdb.base/style.exp
index cc143b4..aec1d0f 100644
--- a/gdb/testsuite/gdb.base/style.exp
+++ b/gdb/testsuite/gdb.base/style.exp
@@ -46,6 +46,16 @@ save_vars { env(TERM) } {
     set main_line [gdb_get_line_number "break here"]
     gdb_test "list $main_line,$main_line" "return.*some_called_function.*"
 
+    gdb_test_no_output "set style enabled off"
+
+    set argv ""
+    gdb_test_multiple "frame" "frame without styling" {
+	-re -wrap "main \\(argc=.*, (argv=$hex)\\).*style\\.c:\[0-9\].*" {
+	    set argv $expect_out(1,string)
+	    pass $gdb_test_name
+	}
+    }
+
     gdb_test_no_output "set style enabled on"
 
     set main_expr [style main function]
@@ -60,7 +70,7 @@ save_vars { env(TERM) } {
     gdb_test_no_output "set style sources off"
     gdb_test "frame" \
 	"\r\n\[^\033\]*break here.*" \
-	"frame without styling"
+	"frame without sources styling"
     gdb_test_no_output "set style sources on"
 
     gdb_test "break -q main" "file $base_file_expr.*"
@@ -71,20 +81,47 @@ save_vars { env(TERM) } {
     # wrong spot with styling.  There were different bugs at different
     # widths, so try two.
     foreach width {20 30} {
-	gdb_test_no_output "set width $width"
+	set argv_len [string length $argv]
+	if { $argv_len == 0 } {
+	    continue
+	}
+
 	# There was also a bug where the styling could be wrong in the
 	# line listing; this is why the words from the source code are
 	# spelled out in the final result line of the test.
-	gdb_test "frame" \
+	set re1_styled \
 	    [multi_line \
 		 "#0 *$main_expr.*$arg_expr.*" \
 		 ".*$arg_expr.*" \
 		 ".* at .*$file_expr.*" \
-		 "\[0-9\]+.*return.* break here .*"
-	    ] \
-	    "frame when width=$width"
+		 "\[0-9\]+.*return.* break here .*"]
+	set re2_styled \
+	    [multi_line \
+		 "#0 *$main_expr.*$arg_expr.*" \
+		 ".*$arg_expr.* at .*$file_expr.*" \
+		 "\[0-9\]+.*return.* break here .*"]
+
+	# The length of the line containing argv containing:
+	# - 4 leading spaces
+	# - argv string
+	# - closing parenthesis
+	set line_len [expr 4 + $argv_len + 1]
+
+	if { $line_len > $width } {
+	    # At on the next line.
+	    set re_styled $re1_styled
+	} else {
+	    # At on the same line as argv.
+	    set re_styled $re2_styled
+	}
+
+	gdb_test_no_output "set width $width"
+	gdb_test "frame" $re_styled "frame when width=$width"
     }
 
+    # Reset width back to 0.
+    gdb_test_no_output "set width 0"
+
     if {$test_macros} {
 	set macro_line [gdb_get_line_number "\#define SOME_MACRO"]
 	gdb_test "info macro SOME_MACRO" \