New TESTS variable to run a subset of tests in parallel.

* Makefile.in (TESTS): New variable.
	(expanded_tests, expanded_tests_or_none): New variables
	(check-single): Pass $(expanded_tests_or_none) to runtest.
	(check-parallel): Only run tests in $(TESTS) if non-empty.
	(check/no-matching-tests-found): New rule.
	* README: Document TESTS makefile variable.

gdb/testsuite/ChangeLog

@@ -1,3 +1,12 @@
+2014-02-18  Doug Evans  <dje@google.com>
+
+	* Makefile.in (TESTS): New variable.
+	(expanded_tests, expanded_tests_or_none): New variables
+	(check-single): Pass $(expanded_tests_or_none) to runtest.
+	(check-parallel): Only run tests in $(TESTS) if non-empty.
+	(check/no-matching-tests-found): New rule.
+	* README: Document TESTS makefile variable.
+
 2014-02-18  Doug Evans  <dje@google.com>
 
 	* Makefile.in (check-parallel): rm -rf outputs temp.

gdb/testsuite/Makefile.in

@@ -160,8 +160,25 @@ DO_RUNTEST = \
 	  export TCL_LIBRARY ; fi ; \
 	$(RUNTEST)
 
+# TESTS exists for the user to pass on the command line to easily
+# say "Only run these tests."  With check-single it's not necessary, but
+# with check-parallel there's no other way to (easily) specify a subset
+# of tests.  For consistency we support it for check-single as well.
+# To specify all tests in a subdirectory, use TESTS=gdb.subdir/*.exp.
+# E.g., make check TESTS="gdb.server/*.exp gdb.threads/*.exp".
+@GMAKE_TRUE@TESTS :=
+@GMAKE_FALSE@TESTS =
+
+@GMAKE_TRUE@ifeq ($(strip $(TESTS)),)
+@GMAKE_TRUE@expanded_tests_or_none :=
+@GMAKE_TRUE@else
+@GMAKE_TRUE@expanded_tests := $(patsubst $(srcdir)/%,%,$(wildcard $(addprefix $(srcdir)/,$(TESTS))))
+@GMAKE_TRUE@expanded_tests_or_none := $(or $(expanded_tests),no-matching-tests-found)
+@GMAKE_TRUE@endif
+@GMAKE_FALSE@expanded_tests_or_none = $(TESTS)
+
 check-single:
-	$(DO_RUNTEST) $(RUNTESTFLAGS)
+	$(DO_RUNTEST) $(RUNTESTFLAGS) $(expanded_tests_or_none)
 
 check-parallel:
 	-rm -rf cache outputs temp
@@ -180,11 +197,15 @@ check-parallel:
 # them to the front of the list to try to lessen the overall time
 # taken by the test suite -- if one of these tests happens to be run
 # late, it will cause the overall time to increase.
+@GMAKE_TRUE@ifeq ($(strip $(TESTS)),)
 slow_tests = gdb.base/break-interp.exp gdb.base/interp.exp \
 	gdb.base/multi-forks.exp
 @GMAKE_TRUE@all_tests := $(shell cd $(srcdir) && find gdb.* -name '*.exp' -print)
 @GMAKE_TRUE@reordered_tests := $(slow_tests) $(filter-out $(slow_tests),$(all_tests))
 @GMAKE_TRUE@TEST_TARGETS := $(addprefix check/,$(reordered_tests))
+@GMAKE_TRUE@else
+@GMAKE_TRUE@TEST_TARGETS := $(addprefix check/,$(expanded_tests_or_none))
+@GMAKE_TRUE@endif
 
 do-check-parallel: $(TEST_TARGETS)
 	@:
@@ -193,6 +214,11 @@ do-check-parallel: $(TEST_TARGETS)
 @GMAKE_TRUE@	-mkdir -p outputs/$*
 @GMAKE_TRUE@	@$(DO_RUNTEST) GDB_PARALLEL=yes --outdir=outputs/$* $*.exp $(RUNTESTFLAGS)
 
+check/no-matching-tests-found:
+	@echo ""
+	@echo "No matching tests found."
+	@echo ""
+
 check-perf: all $(abs_builddir)/site.exp
 	@if test ! -d gdb.perf; then mkdir gdb.perf; fi
 	$(DO_RUNTEST) --directory=gdb.perf --outdir gdb.perf GDB_PERFTEST_MODE=both $(RUNTESTFLAGS)

gdb/testsuite/README

@@ -151,6 +151,30 @@ them, both to stdout and in the test suite log file.
 
 This setting is only meaningful in conjunction with GDB_PARALLEL.
 
+TESTS
+
+This variable is used to specify which set of tests to run.
+It is passed to make (not runtest) and its contents are a space separated
+list of tests to run.
+
+If using GNU make then the contents are wildcard-expanded using
+GNU make's $(wildcard) function.  Test paths must be fully specified,
+relative to the "testsuite" subdirectory.  This allows one to run all
+tests in a subdirectory by passing "gdb.subdir/*.exp".
+If for some strange reason one wanted to run all tests that begin with
+the letter "d" that is also possible: TESTS="*/d*.exp".
+
+Do not write */*.exp to specify all tests (assuming all tests are only
+nested one level deep, which is not necessarily true).  This will pick up
+.exp files in ancillary directories like "lib" and "config".
+Instead write gdb.*/*.exp.
+
+Example:
+
+	make -j10 check TESTS="gdb.server/[s-w]*.exp */x*.exp"
+
+If not using GNU make then the value is passed directly to runtest.
+If not specified, all tests are run.
 
 Testsuite Configuration
 ***********************