Document gdb.in/gdb.cmd files and debugredirect cli command

Add missing documentation for the debugredirect setting.

Add description and uses of gdb.in/gdb.cmd to the testsuite README.

Mention this in the NEWS file.

gdb/ChangeLog:

	* NEWS: Add debugredirect and testsuite sections.

gdb/doc/ChangeLog:

	* gdb.texinfo (Shell Commands): Add debugredirect.

gdb/testsuite/ChangeLog:

	* README (Re-running Tests Outside The Testsuite): New section.

gdb/ChangeLog

@@ -1,3 +1,7 @@
+2019-05-22  Alan Hayward  <alan.hayward@arm.com>
+
+	* NEWS: Add debugredirect and testsuite sections.
+
 2019-05-22  Simon Cook  <simon.cook@embecosm.com>
 
 	* riscv-tdep.c (riscv_gdbarch_init): Support determining flen from

gdb/NEWS

@@ -46,6 +46,10 @@ show print max-depth
   The default max-depth is 20, but this can be set to unlimited to get
   the old behavior back.
 
+set logging debugredirect [on|off]
+  By default, GDB debug output will go to both the terminal and the logfile.
+  Set if you want debug output to go only to the log file.
+
 * New MI commands
 
 -complete
@@ -53,6 +57,13 @@ show print max-depth
   were to be given as a command itself.  This is intended for use by MI
   frontends in cases when separate CLI and MI channels cannot be used.
 
+* Testsuite
+
+  The testsuite now creates the files gdb.cmd (containing the arguments
+  used to launch GDB) and gdb.in (containing all the commands sent to
+  GDB) in the output directory for each test script.  Multiple invocations
+  are appended with .1, .2, .3 etc.
+
 *** Changes in GDB 8.3
 
 * GDB and GDBserver now support access to additional registers on

gdb/doc/ChangeLog

@@ -1,3 +1,7 @@
+2019-05-22  Alan Hayward  <alan.hayward@arm.com>
+
+	* gdb.texinfo (Shell Commands): Add debugredirect.
+
 2019-05-22  Jan Vrany  <jan.vrany@fit.cvut.cz>
 
 	* gdb.texinfo: Minor formatting fixes.

gdb/doc/gdb.texinfo

@@ -1477,6 +1477,9 @@ you want @code{set logging on} to overwrite the logfile instead.
 @item set logging redirect [on|off]
 By default, @value{GDBN} output will go to both the terminal and the logfile.
 Set @code{redirect} if you want output to go only to the log file.
+@item set logging debugredirect [on|off]
+By default, @value{GDBN} debug output will go to both the terminal and the logfile.
+Set @code{debugredirect} if you want debug output to go only to the log file.
 @kindex show logging
 @item show logging
 Show the current values of the logging settings.

gdb/testsuite/ChangeLog

@@ -1,3 +1,7 @@
+2019-05-22  Alan Hayward  <alan.hayward@arm.com>
+
+	* README (Re-running Tests Outside The Testsuite): New section.
+
 2019-05-21  Tom de Vries  <tdevries@suse.de>
 
 	* gdb.arch/amd64-eval.exp: Require c++11.

gdb/testsuite/README

@@ -95,6 +95,27 @@ example:
 
 The script will output its analysis report to the standard output.
 
+Re-running Tests Outside The Testsuite
+**************************************
+
+When running a test, the arguments used to run GDB are saved to gdb.cmd and
+all commands sent to GDB are saved to gdb.in.  As well as being a reference
+of the commands run, they can be used to manually re-run a test by using
+the gdb.in file as a batch file to a GDB launched with the arguments in the
+gdb.cmd file, for example:
+	$(cat outputs/gdb.base/store/gdb.cmd) -x outputs/gdb.base/store/gdb.in
+
+Tests that run GDB multiple times will append .1, .2, .3 etc to the end
+of each .cmd and .in file.
+
+When gdbserver is launched as part of a test, a gdbserver.cmd will be created.
+To re-run these tests, run the contents of gdbserver.cmd in a separate
+terminal before running gdb, for example:
+	$(cat outputs/gdb.base/store/gdbserver.cmd)
+Alternatively, if the test is run with GDBSERVER_DEBUG="replay", then this
+will create a gdbserver.replay file which can be used with the gdbreplay tool,
+instead of launching gdbserver.
+
 Running the Performance Tests
 *****************************