8293116: Incremental JDK build could be sped up

Reviewed-by: erikj, vromero, ihse

make/CompileInterimLangtools.gmk

@@ -1,5 +1,5 @@
 #
-# Copyright (c) 2014, 2021, 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
@@ -48,6 +48,30 @@ $(BUILDTOOLS_OUTPUTDIR)/gensrc/%.interim/module-info.java: \
 TARGETS += $(patsubst %, $(BUILDTOOLS_OUTPUTDIR)/gensrc/%/module-info.java, \
     $(INTERIM_LANGTOOLS_MODULES))
 
+################################################################################
+# Generate interim versions of the ToolProvider.java files for the interim
+# langtools modules, which will allow to load javac from the interim
+# jdk.compiler.
+
+INTERIM_TOOL_PROVIDER_PATTERN := \
+    $(foreach m, $(INTERIM_LANGTOOLS_BASE_MODULES), -e 's/"$m"/"$m.interim"/g')
+
+$(BUILDTOOLS_OUTPUTDIR)/gensrc/java.compiler.interim/javax/tools/ToolProvider.java: \
+    $(TOPDIR)/src/java.compiler/share/classes/javax/tools/ToolProvider.java
+	$(call LogInfo, Generating ToolProvider.java for java.compiler.interim)
+	$(call MakeDir, $(@D))
+	$(SED) $(INTERIM_TOOL_PROVIDER_PATTERN) $< > $@
+
+java.compiler.interim_EXTRA_FILES := \
+     $(BUILDTOOLS_OUTPUTDIR)/gensrc/java.compiler.interim/javax/tools/ToolProvider.java
+
+TARGETS += $(BUILDTOOLS_OUTPUTDIR)/gensrc/java.compiler.interim/javax/tools/ToolProvider.java
+
+################################################################################
+# Use the up-to-date PreviewFeature.java and NoPreview.java from the current
+# sources, instead of the versions from the boot JDK, as javac may be referring
+# to constants from the up-to-date versions.
+
 $(eval $(call SetupCopyFiles, COPY_PREVIEW_FEATURES, \
     FILES := $(TOPDIR)/src/java.base/share/classes/jdk/internal/javac/PreviewFeature.java \
         $(TOPDIR)/src/java.base/share/classes/jdk/internal/javac/NoPreview.java, \
@@ -73,8 +97,10 @@ define SetupInterimModule
           $(TOPDIR)/src/$1/share/classes, \
       EXCLUDES := sun javax/tools/snippet-files, \
       EXCLUDE_FILES := $(TOPDIR)/src/$1/share/classes/module-info.java \
+          $(TOPDIR)/src/$1/share/classes/javax/tools/ToolProvider.java \
           Standard.java, \
-      EXTRA_FILES := $(BUILDTOOLS_OUTPUTDIR)/gensrc/$1.interim/module-info.java, \
+      EXTRA_FILES := $(BUILDTOOLS_OUTPUTDIR)/gensrc/$1.interim/module-info.java \
+          $($1.interim_EXTRA_FILES), \
       COPY := .gif .png .xml .css .svg .js .js.template .txt javax.tools.JavaCompilerTool, \
       BIN := $(BUILDTOOLS_OUTPUTDIR)/interim_langtools_modules/$1.interim, \
       DISABLED_WARNINGS := module options, \

make/CompileJavaModules.gmk

@@ -121,8 +121,8 @@ TARGETS += $($(MODULE))
 # Since the other modules are declared in different invocations of this file,
 # use the macro to find the correct target file to depend on.
 # Only the javac compilation actually depends on other modules so limit
-# dependency declaration to that by using the *_COMPILE_TARGET variable.
-$($(MODULE)_COMPILE_TARGET): $(foreach d, $(call FindDepsForModule, $(MODULE)), \
+# dependency declaration to that by using the *_MODFILELIST variable.
+$($(MODULE)_MODFILELIST): $(foreach d, $(call FindDepsForModule, $(MODULE)), \
     $(call SetupJavaCompilationApiTarget, $d, \
         $(if $($d_BIN), $($d_BIN), $(JDK_OUTPUTDIR)/modules/$d)))
 

make/CompileToolsJdk.gmk

@@ -1,5 +1,5 @@
 #
-# Copyright (c) 2011, 2020, Oracle and/or its affiliates. All rights reserved.
+# Copyright (c) 2011, 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
@@ -77,6 +77,13 @@ $(eval $(call SetupJavaCompilation, COMPILE_DEPEND, \
     INCLUDES := build/tools/depend, \
     BIN := $(BUILDTOOLS_OUTPUTDIR)/depend, \
     DISABLED_WARNINGS := options, \
+    JAVAC_FLAGS := \
+        --add-exports jdk.compiler/com.sun.tools.javac.api=ALL-UNNAMED \
+        --add-exports jdk.compiler/com.sun.tools.javac.code=ALL-UNNAMED \
+        --add-exports jdk.compiler/com.sun.tools.javac.comp=ALL-UNNAMED \
+        --add-exports jdk.compiler/com.sun.tools.javac.main=ALL-UNNAMED \
+        --add-exports jdk.compiler/com.sun.tools.javac.tree=ALL-UNNAMED \
+        --add-exports jdk.compiler/com.sun.tools.javac.util=ALL-UNNAMED, \
 ))
 
 DEPEND_SERVICE_PROVIDER := $(BUILDTOOLS_OUTPUTDIR)/depend/META-INF/services/com.sun.source.util.Plugin

make/common/JavaCompilation.gmk

@@ -402,8 +402,10 @@ define SetupJavaCompilationBody
 
     $1_COMPILE_TARGET := $$($1_BIN)$$($1_MODULE_SUBDIR)/_the.$1_batch
     $1_FILELIST := $$($1_BIN)$$($1_MODULE_SUBDIR)/_the.$1_batch.filelist
+    $1_MODFILELIST := $$($1_BIN)$$($1_MODULE_SUBDIR)/_the.$1_batch.modfiles
 
     $1_API_TARGET := $$($1_BIN)$$($1_MODULE_SUBDIR)/_the.$1_pubapi
+    $1_API_INTERNAL := $$($1_BIN)$$($1_MODULE_SUBDIR)/_the.$1_internalapi
 
     # Put headers in a temp dir to filter out those that actually
     # changed before copying them to the real header dir.
@@ -437,6 +439,8 @@ define SetupJavaCompilationBody
       $1_API_DIGEST_FLAGS := \
           -classpath $$(BUILDTOOLS_OUTPUTDIR)/depend \
           -Xplugin:"depend $$($1_API_TARGET)" \
+          "-XDinternalAPIPath=$$($1_API_INTERNAL)" \
+          "-XDLOG_LEVEL=$(LOG_LEVEL)" \
           #
 
       $1_EXTRA_DEPS := $$(BUILDTOOLS_OUTPUTDIR)/depend/_the.COMPILE_DEPEND_batch
@@ -447,16 +451,33 @@ define SetupJavaCompilationBody
     # list of files.
     $$($1_FILELIST): $$($1_SRCS) $$($1_VARDEPS_FILE)
 		$$(call MakeDir, $$(@D))
-		$$(call LogWarn, Compiling $$(words $$($1_SRCS)) files for $1)
+		$$(call LogWarn, Compiling up to $$(words $$($1_SRCS)) files for $1)
 		$$(eval $$(call ListPathsSafely, $1_SRCS, $$($1_FILELIST)))
 
+    # Create a $$($1_MODFILELIST) file with significant modified dependencies
+    # (either sources files or the other mark dependencies).
+    # It is then sent using a side-channel
+    # to the custom Depend plugin. The Depend plugin will check the provided list
+    # of modified files, and if none of the Java source files is changed in a way
+    # observable from outside of the file, and the list of modified files does
+    # not include a non-Java source file, it will only compile the modified files.
+    # Otherwise, all module's sources will be compiled. If a non-Java file is included,
+    # it will be considered to be a significant change, and all module source will
+    # be recompiled
+    $$($1_MODFILELIST): $$($1_SRCS) $$($1_DEPENDS) \
+        $$($1_VARDEPS_FILE) $$($1_EXTRA_DEPS) $$($1_JAVAC_SERVER_CONFIG)
+		$$(eval $1_MODFILES := $$?)
+		$$(eval $$(call ListPathsSafely, $1_MODFILES, $$($1_MODFILELIST)))
+
     # Do the actual compilation
     $$($1_COMPILE_TARGET): $$($1_SRCS) $$($1_FILELIST) $$($1_DEPENDS) \
-        $$($1_VARDEPS_FILE) $$($1_EXTRA_DEPS) $$($1_JAVAC_SERVER_CONFIG)
+        $$($1_VARDEPS_FILE) $$($1_EXTRA_DEPS) $$($1_JAVAC_SERVER_CONFIG) \
+        $$($1_MODFILELIST)
 		$$(call MakeDir, $$(@D))
 		$$(call ExecuteWithLog, $$($1_BIN)$$($1_MODULE_SUBDIR)/_the.$$($1_SAFE_NAME)_batch, \
 		    $$($1_JAVAC_CMD) $$($1_FLAGS) \
 		        $$($1_API_DIGEST_FLAGS) \
+		        -XDmodifiedInputs=$$($1_MODFILELIST) \
 		        -d $$($1_BIN) $$($1_HEADERS_ARG) @$$($1_FILELIST)) && \
 		$(TOUCH) $$@