Modernize llgdb script and make it easier to debug.

Author: adrian-prantl

cross-project-tests/debuginfo-tests/llgdb-tests/test_debuginfo.pl

@@ -56,7 +56,7 @@
 if (!$my_debugger) {
     if ($use_lldb) {
         my $path = dirname(Cwd::abs_path($0));
-        $my_debugger = "/usr/bin/env python3 $path/llgdb.py";
+        $my_debugger = "/usr/bin/xcrun python3 $path/llgdb.py";
     } else {
         $my_debugger = "gdb";
     }
@@ -66,12 +66,18 @@
 my $debugger_options = "-q -batch -n -x";
 
 # run debugger and capture output.
+print("Running debugger\n");
 system("$my_debugger $debugger_options $debugger_script_file $executable_file > $output_file 2>&1");
-
+if ($?) {
+    print("Debugger output was:\n");
+    system("cat", "$output_file");
+    exit 1;
+}
 # validate output.
+print("Running FileCheck\n");
 system("FileCheck", "-input-file", "$output_file", "$testcase_file");
-if ($?>>8 == 1) {
-    print "Debugger output was:\n";
+if ($?) {
+    print("Debugger output was:\n");
     system("cat", "$output_file");
     exit 1;
 }