--- a/make/RunTestsPrebuilt.gmk	Fri Sep 07 15:46:39 2018 -0700
+++ b/make/RunTestsPrebuilt.gmk	Tue Sep 18 16:32:39 2018 -0700
@@ -49,10 +49,11 @@
 # given.
 # Note: No spaces are allowed around the arguments.
 #
-# $1: The name of the argument
+# $1: The name of the variable
 # $2: The default value, if any, or OPTIONAL (do not provide a default but
 #     do not exit if it is missing)
 # $3: If NO_CHECK, disable checking for target file/directory existence
+#     If MKDIR, create the default directory
 define SetupVariable
   ifeq ($$($1), )
     ifeq ($2, )
@@ -75,10 +76,17 @@
   endif
   # If $1 has a value (is not optional), and $3 is not set (to NO_CHECK),
   # and if wildcard is empty, then complain that the file is missing.
-  ifeq ($$(strip $$(if $$($1), , OPTIONAL) $$(wildcard $$($1)) $3), )
-    $$(info Error: Prebuilt variable $1 points to missing file/directory:)
-    $$(info '$$($1)')
-    $$(error Cannot continue.)
+  ifeq ($3, MKDIR)
+    ifneq ($$(findstring $$(LOG), info debug trace), )
+      $$(info Creating directory for $1)
+    endif
+    $$(shell mkdir -p $$($1))
+  else ifneq ($3, NO_CHECK)
+    ifeq ($$(strip $$(if $$($1), , OPTIONAL) $$(wildcard $$($1))), )
+      $$(info Error: Prebuilt variable $1 points to missing file/directory:)
+      $$(info '$$($1)')
+      $$(error Cannot continue.)
+    endif
   endif
 endef
 
@@ -106,14 +114,14 @@
 # Verify that user has given correct additional input.
 
 # These variables are absolutely necessary
-$(eval $(call SetupVariable,OUTPUTDIR))
+$(eval $(call SetupVariable,OUTPUTDIR,$(TOPDIR)/build/run-test-prebuilt,MKDIR))
 $(eval $(call SetupVariable,BOOT_JDK))
 $(eval $(call SetupVariable,JT_HOME))
 
 # These can have default values based on the ones above
 $(eval $(call SetupVariable,JDK_IMAGE_DIR,$(OUTPUTDIR)/images/jdk))
 $(eval $(call SetupVariable,TEST_IMAGE_DIR,$(OUTPUTDIR)/images/test))
-$(eval $(call SetupVariable,SYMBOLS_IMAGE_DIR,$(OUTPUTDIR)/images/symbols))
+$(eval $(call SetupVariable,SYMBOLS_IMAGE_DIR,$(OUTPUTDIR)/images/symbols,NO_CHECK))
 
 # Provide default values for tools that we need
 $(eval $(call SetupVariable,MAKE,make,NO_CHECK))
@@ -202,8 +210,8 @@
 
 ifeq ($(OPENJDK_TARGET_OS), windows)
   ifeq ($(wildcard $(TEST_IMAGE_DIR)/bin/fixpath.exe), )
-    $$(info Error: fixpath is missing from test image '$(TEST_IMAGE_DIR)')
-    $$(error Cannot continue.)
+    $(info Error: fixpath is missing from test image '$(TEST_IMAGE_DIR)')
+    $(error Cannot continue.)
   endif
   FIXPATH := $(TEST_IMAGE_DIR)/bin/fixpath.exe -c
   PATH_SEP:=;
@@ -276,10 +284,6 @@
 	@$(RM) -f $(MAKESUPPORT_OUTPUTDIR)/exit-with-error
 	@cd $(TOPDIR) && $(MAKE) $(MAKE_ARGS) -f make/RunTests.gmk run-test \
 	    TEST="$(TEST)"
-	$(MKDIR) -p $(OUTPUTDIR)/jtreg
-	$(MV) $(OUTPUTDIR)/test-results/`$(HEAD) -n 1 $(OUTPUTDIR)/test-support/test-last-ids.txt` $(OUTPUTDIR)/jtreg/JTreport
-	$(MV) $(OUTPUTDIR)/test-support/`$(HEAD) -n 1 $(OUTPUTDIR)/test-support/test-last-ids.txt` $(OUTPUTDIR)/jtreg/JTwork
-	$(MV) $(OUTPUTDIR)/jtreg/JTreport/exitcode.txt $(OUTPUTDIR)/jtreg/exitcode.txt
 
 all: run-test-prebuilt
 

--- a/make/conf/jib-profiles.js	Fri Sep 07 15:46:39 2018 -0700
+++ b/make/conf/jib-profiles.js	Tue Sep 18 16:32:39 2018 -0700
@@ -766,11 +766,11 @@
         "run-test-prebuilt": {
             target_os: input.build_os,
             target_cpu: input.build_cpu,
+            dependencies: [ "jtreg", "gnumake", "boot_jdk", "jib", testedProfile + ".jdk",
+                testedProfile + ".test"
+            ],
             src: "src.conf",
-            dependencies: [ "jtreg", "gnumake", "boot_jdk", "jib", testedProfile + ".jdk",
-                testedProfile + ".test", "src.full"
-            ],
-            work_dir: input.get("src.full", "install_path"),
+            make_args: [ "run-test-prebuilt" ],
             environment: {
                 "BOOT_JDK": common.boot_jdk_home,
                 "JDK_IMAGE_DIR": input.get(testedProfile + ".jdk", "home_path"),
@@ -820,6 +820,27 @@
             windowsRunTestPrebuiltExtra);
     }
 
+    // The profile run-test-prebuilt defines src.conf as the src bundle. When
+    // running in Mach 5, this reduces the time it takes to populate the
+    // considerably. But with just src.conf, we cannot actually run any tests,
+    // so if running from a workspace with just src.conf in it, we need to also
+    // get src.full as a dependency, and define the work_dir (where make gets
+    // run) to be in the src.full install path. By running in the install path,
+    // the same cached installation of the full src can be reused for multiple
+    // test tasks. Care must however be taken not to polute that work dir by
+    // setting the appropriate make variables to control output directories.
+    //
+    // Use the existance of the top level README as indication of if this is
+    // the full source or just src.conf.
+    if (!new java.io.File(__DIR__, "../../README").exists()) {
+        var runTestPrebuiltSrcFullExtra = {
+            dependencies: "src.full",
+            work_dir: input.get("src.full", "install_path"),
+        }
+        profiles["run-test-prebuilt"] = concatObjects(profiles["run-test-prebuilt"],
+            runTestPrebuiltSrcFullExtra);
+    }
+
     // Generate the missing platform attributes
     profiles = generatePlatformAttributes(profiles);
     profiles = generateDefaultMakeTargetsConfigureArg(common, profiles);