8298459: Fix msys2 linking and handling out of tree build directory for source zip creation

Reviewed-by: erikj

Author: RealCLanger

make/ZipSource.gmk

@@ -1,5 +1,5 @@
 #
-# Copyright (c) 2014, 2020, Oracle and/or its affiliates. All rights reserved.
+# Copyright (c) 2014, 2022, Oracle and/or its affiliates. All rights reserved.
 # DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
 #
 # This code is free software; you can redistribute it and/or modify it
@@ -31,6 +31,7 @@ include JavaCompilation.gmk
 include Modules.gmk
 
 SRC_ZIP_WORK_DIR := $(SUPPORT_OUTPUTDIR)/src
+$(if $(filter $(TOPDIR)/%, $(SUPPORT_OUTPUTDIR)), $(eval SRC_ZIP_BASE := $(TOPDIR)), $(eval SRC_ZIP_BASE := $(SUPPORT_OUTPUTDIR)))
 
 # Hook to include the corresponding custom file, if present.
 $(eval $(call IncludeCustomExtension, ZipSource.gmk))
@@ -45,10 +46,10 @@ ALL_MODULES := $(FindAllModules)
 # again to create src.zip.
 $(foreach m, $(ALL_MODULES), \
   $(foreach d, $(call FindModuleSrcDirs, $m), \
-    $(eval $d_TARGET := $(SRC_ZIP_WORK_DIR)/$(patsubst $(TOPDIR)/%,%,$d)/$m) \
+    $(eval $d_TARGET := $(SRC_ZIP_WORK_DIR)/$(patsubst $(TOPDIR)/%,%,$(patsubst $(SUPPORT_OUTPUTDIR)/%,%,$d))/$m) \
     $(if $(SRC_GENERATED), , \
       $(eval $$($d_TARGET): $d ; \
-          $$(if $(filter $(TOPDIR)/%, $d), $$(link-file-relative), $$(link-file-absolute)) \
+          $$(if $(filter $(SRC_ZIP_BASE)/%, $d), $$(link-file-relative), $$(link-file-absolute)) \
       ) \
     ) \
     $(eval SRC_ZIP_SRCS += $$($d_TARGET)) \

make/common/MakeBase.gmk

@@ -306,17 +306,36 @@ endef
 # There are two versions, either creating a relative or an absolute link. Be
 # careful when using this on Windows since the symlink created is only valid in
 # the unix emulation environment.
-define link-file-relative
+# In msys2 we use mklink /J because its ln would perform a deep copy of the target.
+# This inhibits performance and can lead to issues with long paths. With mklink /J
+# relative linking does not work, so we handle the link as absolute path.
+ifeq ($(OPENJDK_BUILD_OS_ENV), windows.msys2)
+  define link-file-relative
+	$(call MakeTargetDir)
+	$(RM) '$(call DecodeSpace, $@)'
+	cmd //c "mklink /J $(call FixPath, $(call DecodeSpace, $@)) $(call FixPath, $(call DecodeSpace, $<))"
+  endef
+else
+  define link-file-relative
 	$(call MakeTargetDir)
 	$(RM) '$(call DecodeSpace, $@)'
 	$(LN) -s '$(call DecodeSpace, $(call RelativePath, $<, $(@D)))' '$(call DecodeSpace, $@)'
-endef
+  endef
+endif
 
-define link-file-absolute
+ifeq ($(OPENJDK_BUILD_OS_ENV), windows.msys2)
+  define link-file-absolute
+	$(call MakeTargetDir)
+	$(RM) '$(call DecodeSpace, $@)'
+	cmd //c "mklink /J $(call FixPath, $(call DecodeSpace, $@)) $(call FixPath, $(call DecodeSpace, $<))"
+  endef
+else
+  define link-file-absolute
 	$(call MakeTargetDir)
 	$(RM) '$(call DecodeSpace, $@)'
 	$(LN) -s '$(call DecodeSpace, $<)' '$(call DecodeSpace, $@)'
-endef
+  endef
+endif
 
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