From c73d38746e22c0d3e45baafdc62901179c2875c2 Mon Sep 17 00:00:00 2001
From: David Beaumont <david.beaumont@oracle.com>
Date: Tue, 23 Sep 2025 17:52:12 +0200
Subject: [PATCH] Copy value classes into preview directories for inclusion in
 jimage

---
 make/CompileJavaModules.gmk | 24 ++++++++++++++++++++++--
 1 file changed, 22 insertions(+), 2 deletions(-)

diff --git a/make/CompileJavaModules.gmk b/make/CompileJavaModules.gmk
index 3ec32971ed8..2667524df88 100644
--- a/make/CompileJavaModules.gmk
+++ b/make/CompileJavaModules.gmk
@@ -99,13 +99,16 @@ endif
 
 ################################################################################
 # Setup the main compilation
+
+COMPILATION_OUTPUTDIR := $(if $($(MODULE)_BIN), $($(MODULE)_BIN), $(JDK_OUTPUTDIR)/modules)
+
 $(eval $(call SetupJavaCompilation, $(MODULE), \
     SMALL_JAVA := false, \
     MODULE := $(MODULE), \
     SRC := $(wildcard $(MODULE_SRC_DIRS)), \
     INCLUDES := $(JDK_USER_DEFINED_FILTER), \
     FAIL_NO_SRC := $(FAIL_NO_SRC), \
-    BIN := $(if $($(MODULE)_BIN), $($(MODULE)_BIN), $(JDK_OUTPUTDIR)/modules), \
+    BIN := $(COMPILATION_OUTPUTDIR), \
     HEADERS := $(SUPPORT_OUTPUTDIR)/headers, \
     CREATE_API_DIGEST := true, \
     CLEAN := $(CLEAN), \
@@ -137,6 +140,15 @@ ifneq ($(COMPILER), bootjdk)
   MODULE_VALUECLASS_SRC_DIRS := $(call FindModuleValueClassSrcDirs, $(MODULE))
   MODULE_VALUECLASS_SOURCEPATH := $(call GetModuleValueClassSrcPath)
 
+  # Temporarily compile valueclasses into a separate directory with the form:
+  #   <tempdir>/<module>/<classpath>
+  # and then copy the class files into:
+  #   <outdir>/<module>/META-INF/preview/<classpath>
+  # We cannot compile directly into the desired directory because it's the
+  # compiler which creates the original '<module>/<classpath>/...' hierarchy.
+  VALUECLASS_OUTPUTDIR := $(SUPPORT_OUTPUTDIR)/$(VALUECLASSES_STR)
+  PREVIEW_OUTPUTDIR := $(COMPILATION_OUTPUTDIR)/$(MODULE)/META-INF/preview
+
   ifneq ($(MODULE_VALUECLASS_SRC_DIRS),)
     $(eval $(call SetupJavaCompilation, $(MODULE)-$(VALUECLASSES_STR), \
         SMALL_JAVA := false, \
@@ -144,7 +156,7 @@ ifneq ($(COMPILER), bootjdk)
         SRC := $(wildcard $(MODULE_VALUECLASS_SRC_DIRS)), \
         INCLUDES := $(JDK_USER_DEFINED_FILTER), \
         FAIL_NO_SRC := $(FAIL_NO_SRC), \
-        BIN := $(SUPPORT_OUTPUTDIR)/$(VALUECLASSES_STR)/, \
+        BIN := $(VALUECLASS_OUTPUTDIR)/, \
         JAR := $(JDK_OUTPUTDIR)/lib/$(VALUECLASSES_STR)/$(MODULE)-$(VALUECLASSES_STR).jar, \
         HEADERS := $(SUPPORT_OUTPUTDIR)/headers, \
         DISABLED_WARNINGS := $(DISABLED_WARNINGS_java) preview, \
@@ -162,6 +174,14 @@ ifneq ($(COMPILER), bootjdk)
 
     TARGETS += $($(MODULE)-$(VALUECLASSES_STR))
 
+    # Restructure the class file hierarchy from <module>/<classpath>/... to <module>/META-INF/preview/<classpath>/...
+    $(PREVIEW_OUTPUTDIR)/_copy_valueclasses.marker: $($(MODULE)-$(VALUECLASSES_STR))
+		$(call MakeTargetDir)
+		$(CP) -R $(VALUECLASS_OUTPUTDIR)/$(MODULE)/. $(@D)/
+		$(TOUCH) $@
+
+    TARGETS += $(PREVIEW_OUTPUTDIR)/_copy_valueclasses.marker
+
     $(eval $(call SetupCopyFiles, $(MODULE)-copy-valueclass-jar, \
         FILES := $(JDK_OUTPUTDIR)/lib/$(VALUECLASSES_STR)/$(MODULE)-$(VALUECLASSES_STR).jar, \
         DEST := $(SUPPORT_OUTPUTDIR)/modules_libs/$(MODULE)/$(VALUECLASSES_STR), \