diff --git a/make/CompileJavaModules.gmk b/make/CompileJavaModules.gmk
index 1e26fb2b529cc..c6e8fab30387c 100644
--- a/make/CompileJavaModules.gmk
+++ b/make/CompileJavaModules.gmk
@@ -85,7 +85,7 @@ CreateHkTargets = \
 ################################################################################
 # Include module specific build settings
 
-THIS_SNIPPET := modules/$(MODULE)/Java.gmk
+THIS_SNIPPET := $(call GetModuleSnippetName, Java)
 
 ifneq ($(wildcard $(THIS_SNIPPET)), )
   include MakeSnippetStart.gmk
diff --git a/make/CreateJmods.gmk b/make/CreateJmods.gmk
index 40bceda69a97f..a26042fb0d553 100644
--- a/make/CreateJmods.gmk
+++ b/make/CreateJmods.gmk
@@ -184,7 +184,7 @@ endif
 ################################################################################
 # Include module specific build settings
 
-THIS_SNIPPET := modules/$(MODULE)/Jmod.gmk
+THIS_SNIPPET := $(call GetModuleSnippetName, Jmod)
 
 ifneq ($(wildcard $(THIS_SNIPPET)), )
   include MakeSnippetStart.gmk
diff --git a/make/Images.gmk b/make/Images.gmk
index 22e3e43cb1f33..34d81081d2968 100644
--- a/make/Images.gmk
+++ b/make/Images.gmk
@@ -270,6 +270,7 @@ endif
 # Since debug symbols are not included in the jmod files, they need to be copied
 # in manually after generating the images.
 
+# These variables are read by SetupCopyDebuginfo
 ALL_JDK_MODULES := $(JDK_MODULES)
 ALL_JRE_MODULES := $(sort $(JRE_MODULES), $(foreach m, $(JRE_MODULES), \
     $(call FindTransitiveDepsForModule, $m)))
diff --git a/make/Main.gmk b/make/Main.gmk
index d0568509a4e5b..f8712c69b2737 100644
--- a/make/Main.gmk
+++ b/make/Main.gmk
@@ -1407,7 +1407,7 @@ CLEAN_SUPPORT_DIRS += demos
 CLEAN_SUPPORT_DIR_TARGETS := $(addprefix clean-, $(CLEAN_SUPPORT_DIRS))
 CLEAN_TESTS += hotspot-jtreg-native jdk-jtreg-native lib
 CLEAN_TEST_TARGETS += $(addprefix clean-test-, $(CLEAN_TESTS))
-CLEAN_PHASES := gensrc java native include
+CLEAN_PHASES += gensrc java native include
 CLEAN_PHASE_TARGETS := $(addprefix clean-, $(CLEAN_PHASES))
 CLEAN_MODULE_TARGETS := $(addprefix clean-, $(ALL_MODULES))
 # Construct targets of the form clean-$module-$phase
diff --git a/make/MainSupport.gmk b/make/MainSupport.gmk
index d8dc894c1e983..ee5bb324f8f0a 100644
--- a/make/MainSupport.gmk
+++ b/make/MainSupport.gmk
@@ -149,7 +149,7 @@ endef
 
 ################################################################################
 
-PHASE_MAKEDIRS := $(TOPDIR)/make
+PHASE_MAKEDIRS += $(TOPDIR)/make
 
 # Helper macro for DeclareRecipesForPhase
 # Declare a recipe for calling the module and phase specific makefile.
diff --git a/make/ModuleWrapper.gmk b/make/ModuleWrapper.gmk
index b3ddf940e008c..2db77b9ea3288 100644
--- a/make/ModuleWrapper.gmk
+++ b/make/ModuleWrapper.gmk
@@ -34,18 +34,23 @@ include MakeFileStart.gmk
 ################################################################################
 
 include CopyFiles.gmk
+include Modules.gmk
 
 MODULE_SRC := $(TOPDIR)/src/$(MODULE)
 
-# Define the snippet for MakeSnippetStart/End
-THIS_SNIPPET := modules/$(MODULE)/$(MAKEFILE_PREFIX).gmk
+################################################################################
+# Include module specific build settings
+
+THIS_SNIPPET := $(call GetModuleSnippetName, $(MAKEFILE_PREFIX))
 
-include MakeSnippetStart.gmk
+ifneq ($(wildcard $(THIS_SNIPPET)), )
+  include MakeSnippetStart.gmk
 
-# Include the file being wrapped.
-include $(THIS_SNIPPET)
+  # Include the file being wrapped.
+  include $(THIS_SNIPPET)
 
-include MakeSnippetEnd.gmk
+  include MakeSnippetEnd.gmk
+endif
 
 ifeq ($(MAKEFILE_PREFIX), Lib)
   # We need to keep track of what libraries are generated/needed by this
diff --git a/make/common/JavaCompilation.gmk b/make/common/JavaCompilation.gmk
index c5a74413de19e..99672d5988484 100644
--- a/make/common/JavaCompilation.gmk
+++ b/make/common/JavaCompilation.gmk
@@ -178,6 +178,10 @@ define SetupJavaCompilationBody
 
   $1_SAFE_NAME := $$(strip $$(subst /,_, $1))
 
+  ifeq ($$($1_LOG_ACTION), )
+    $1_LOG_ACTION := Compiling
+  endif
+
   ifeq ($$($1_SMALL_JAVA), )
     # If unspecified, default to true
     $1_SMALL_JAVA := true
@@ -472,7 +476,7 @@ define SetupJavaCompilationBody
     # list of files.
     $$($1_FILELIST): $$($1_SRCS) $$($1_VARDEPS_FILE)
 		$$(call MakeDir, $$(@D))
-		$$(call LogWarn, Compiling up to $$(words $$($1_SRCS)) files for $1)
+		$$(call LogWarn, $$($1_LOG_ACTION) up to $$(words $$($1_SRCS)) files for $1)
 		$$(eval $$(call ListPathsSafely, $1_SRCS, $$($1_FILELIST)))
 
     # Create a $$($1_MODFILELIST) file with significant modified dependencies
diff --git a/make/common/Modules.gmk b/make/common/Modules.gmk
index 725424d7618da..2880504676aa4 100644
--- a/make/common/Modules.gmk
+++ b/make/common/Modules.gmk
@@ -33,7 +33,7 @@ include $(TOPDIR)/make/conf/module-loader-map.conf
 
 # Append platform-specific and upgradeable modules
 PLATFORM_MODULES += $(PLATFORM_MODULES_$(OPENJDK_TARGET_OS)) \
-    $(UPGRADEABLE_PLATFORM_MODULES)
+    $(UPGRADEABLE_PLATFORM_MODULES) $(CUSTOM_UPGRADEABLE_PLATFORM_MODULES)
 
 ################################################################################
 # Setup module sets for docs
@@ -216,7 +216,7 @@ endif
 # Find dependencies ("requires") for a given module.
 # Param 1: Module to find dependencies for.
 FindDepsForModule = \
-  $(DEPS_$(strip $1))
+  $(filter-out $(IMPORT_MODULES), $(DEPS_$(strip $1)))
 
 # Find dependencies ("requires") transitively in 3 levels for a given module.
 # Param 1: Module to find dependencies for.
@@ -254,7 +254,8 @@ FindTransitiveIndirectDepsForModules = \
 # Upgradeable modules are those that are either defined as upgradeable or that
 # require an upradeable module.
 FindAllUpgradeableModules = \
-    $(sort $(filter-out $(MODULES_FILTER), $(UPGRADEABLE_PLATFORM_MODULES)))
+    $(sort $(filter-out $(MODULES_FILTER), \
+    $(UPGRADEABLE_PLATFORM_MODULES) $(CUSTOM_UPGRADEABLE_PLATFORM_MODULES)))
 
 ################################################################################
 
@@ -316,6 +317,19 @@ define ReadImportMetaData
       $$(eval $$(call ReadSingleImportMetaData, $$m)))
 endef
 
+################################################################################
+# Get a full snippet path for the current module and a given base name.
+#
+# Param 1 - The base name of the snippet file to include
+GetModuleSnippetName = \
+  $(if $(CUSTOM_MODULE_MAKE_ROOT), \
+    $(if $(wildcard $(CUSTOM_MODULE_MAKE_ROOT)/$(MODULE)/$(strip $1).gmk), \
+      $(CUSTOM_MODULE_MAKE_ROOT)/$(MODULE)/$(strip $1).gmk, \
+      $(wildcard modules/$(MODULE)/$(strip $1).gmk) \
+    ), \
+    $(wildcard modules/$(MODULE)/$(strip $1).gmk) \
+  )
+
 ################################################################################
 
 endif # include guard