[PATCH v2 01/17] fix up log-file toggling

[Tom Tromey <tromey@redhat.com>]

Currently a proc in gdb.exp toggles the expect (and thus dejagnu)
logging.  This is not a super idea, but it is there to avoid putting
some preprocessor output into the log.

In the right circumstances, this can result in the log file being
mysteriously truncated.  I think this happens because it doesn't
necessarily write to the correct log file again.

The fix is to use "log_file -info" to save the previous log file.

	* lib/gdb.exp (get_compiler_info): Use log_file -info and
	restore from that.
---
 gdb/testsuite/lib/gdb.exp | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/gdb/testsuite/lib/gdb.exp b/gdb/testsuite/lib/gdb.exp
index 44786ec..fbb9f71 100644
--- a/gdb/testsuite/lib/gdb.exp
+++ b/gdb/testsuite/lib/gdb.exp
@@ -2406,6 +2406,7 @@ proc get_compiler_info {{arg ""}} {
 
     # Run $ifile through the right preprocessor.
     # Toggle gdb.log to keep the compiler output out of the log.
+    set saved_log [log_file -info]
     log_file
     if [is_remote host] {
 	# We have to use -E and -o together, despite the comments
@@ -2418,7 +2419,7 @@ proc get_compiler_info {{arg ""}} {
     } else {
 	set cppout [ gdb_compile "${ifile}" "" preprocess [list "$arg" quiet] ]
     }
-    log_file -a "$outdir/$tool.log" 
+    eval log_file $saved_log
 
     # Eval the output.
     set unknown 0
-- 
1.8.1.4