RFA: make test suite transcripts

[Tom Tromey <tromey at redhat dot com>]

I've often wished there were a simple way to ask the test suite to
record all the commands sent to gdb, so that I could more easily
reproduce a failure.

This patch adds a simple transcription facility to the test suite.
This will record the gdb command line and all commands sent to gdb;
the transcript for each invocation of gdb is written to a separate
file.  While imperfect (it doesn't handle readline stuff well), it has
already saved me quite a bit of futzing.

Let me know what you think.

The documentation needs a review.

Tom

2009-07-09  Tom Tromey  <tromey@redhat.com>

	* gdbint.texinfo (Testsuite): Document test transcripts.

2009-07-09  Tom Tromey  <tromey@redhat.com>

	* lib/gdb.exp: Handle LOG_GDB_SCRIPT.
	(remote_spawn, remote_close, send_gdb): New procs.

diff --git a/gdb/doc/gdbint.texinfo b/gdb/doc/gdbint.texinfo
index a51f077..1a54940 100644
--- a/gdb/doc/gdbint.texinfo
+++ b/gdb/doc/gdbint.texinfo
@@ -7560,6 +7560,27 @@ will give a result of ``UNRESOLVED'', like this:
 UNRESOLVED: gdb.base/example.exp: This test script does not work on a remote host.
 @end smallexample
 
+Sometimes it is convenient to get a transcript of the commands which
+the testsuite sends to @value{GDBN}.  For example, if @value{GDBN}
+crashes during testing, a transcript can be used to more easily
+reconstruct the failure when running @value{GDBN} under @value{GDBN}.
+
+You can instruct the @value{GDBN} testsuite to write transcripts by
+setting the environment variable @code{LOG_GDB_SCRIPT} (to any value)
+before invoking @code{runtest} or @code{make check}.  The transcripts
+will be written into DejaGNU's output directory.  One transcript will
+be made for each invocation of @value{GDBN}; they will be named
+@file{transcript.@var{n}}, where @var{n} is an integer.  The first
+line of the transcript file will show how @value{GDBN} was invoked;
+each subsequent line is a command sent as input to @value{GDBN}.
+
+@smallexample
+LOG_GDB_SCRIPT=y make check
+@end smallexample
+
+Note that the transcript is not always complete.  In particular, tests
+of completion can yield partial command lines.
+
 @section Testsuite Organization
 
 @cindex test suite organization
diff --git a/gdb/testsuite/lib/gdb.exp b/gdb/testsuite/lib/gdb.exp
index 200ab35..6964b96 100644
--- a/gdb/testsuite/lib/gdb.exp
+++ b/gdb/testsuite/lib/gdb.exp
@@ -2983,3 +2983,49 @@ proc get_sizeof { type default } {
     return [get_integer_valueof "sizeof (${type})" $default]
 }
 
+# Log gdb command line and script if requested.
+if {[info exists env(LOG_GDB_SCRIPT)]} {
+  rename send_gdb real_send_gdb
+  rename remote_spawn real_remote_spawn
+  rename remote_close real_remote_close
+
+  global gdb_transcript
+  set gdb_transcript ""
+
+  global gdb_trans_count
+  set gdb_trans_count 1
+
+  proc remote_spawn {args} {
+    global gdb_transcript gdb_trans_count outdir
+
+    if {$gdb_transcript != ""} {
+      close $gdb_transcript
+    }
+    set gdb_transcript [open [file join $outdir transcript.$gdb_trans_count] w]
+    puts $gdb_transcript [lindex $args 1]
+    incr gdb_trans_count
+
+    return [uplevel real_remote_spawn $args]
+  }
+
+  proc remote_close {args} {
+    global gdb_transcript
+
+    if {$gdb_transcript != ""} {
+      close $gdb_transcript
+      set gdb_transcript ""
+    }
+
+    return [uplevel real_remote_close $args]
+  }
+
+  proc send_gdb {args} {
+    global gdb_transcript
+
+    if {$gdb_transcript != ""} {
+      puts -nonewline $gdb_transcript [lindex $args 0]
+    }
+
+    return [uplevel real_send_gdb $args]
+  }
+}