Reduce unnecessary rebuilds of .dex files with restat=1

The .dex.toc files are created by dexdump, which outputs all
information in a .dex file which may affect compilation of
other modules.

For prebuilt java libraries and static java libraries, we'll
output empty .toc files and don't set restat=1. .dex.toc files
are necessary even for static java libraries because they can
be referenced by LOCAL_JAVA_LIBRARIES (instead of
LOCAL_STATIC_JAVA_LIBRARIES).

We don't use this optimization for apps build. We cannot build
dexdump for apps build due to lack of libc++.

Performance:

$ m && touch \
  frameworks/base/core/java/com/google/android/util/Procedure.java \
  && time m
Before: 3m48s
After: 1m46s

Bug: 24597504
Change-Id: Id1665923b414dee705dc60af4c021390a19ea26f

core/config.mk

@@ -571,6 +571,7 @@ endif
 # ijar converts a .jar file to a smaller .jar file which only has its
 # interfaces.
 IJAR := $(HOST_OUT_EXECUTABLES)/ijar$(BUILD_EXECUTABLE_SUFFIX)
+DEXDUMP := $(HOST_OUT_EXECUTABLES)/dexdump2$(BUILD_EXECUTABLE_SUFFIX)
 
 # relocation packer
 RELOCATION_PACKER := prebuilts/misc/$(BUILD_OS)-$(HOST_PREBUILT_ARCH)/relocation_packer/relocation_packer

core/definitions.mk

@@ -1948,9 +1948,9 @@ $(hide) mv $1.tmp $1
 endef
 endif
 
-## Rule to creates a table of contents from a .jar file.
+## Rule to create a table of contents from a .jar file.
 ## Must be called with $(eval).
-# $1: A .jar file
+# $(1): A .jar file
 define _transform-jar-to-toc
 $1.toc: $1 | $(IJAR)
 	@echo Generating TOC: $$@
@@ -1959,11 +1959,40 @@ $1.toc: $1 | $(IJAR)
 endef
 
 ## Define a rule which generates .jar.toc and mark it as .KATI_RESTAT.
+# $(1): A .jar file
 define define-jar-to-toc-rule
 $(eval $(call _transform-jar-to-toc,$1))\
 $(eval .KATI_RESTAT: $1.toc)
 endef
 
+ifeq (,$(TARGET_BUILD_APPS))
+
+## Rule to create a table of contents from a .dex file.
+## Must be called with $(eval).
+# $(1): The directory which contains classes*.dex files
+define _transform-dex-to-toc
+$1/classes.dex.toc: PRIVATE_INPUT_DEX_FILES := $1/classes*.dex
+$1/classes.dex.toc: $1/classes.dex $(DEXDUMP)
+	@echo Generating TOC: $$@
+	$(hide) $(DEXDUMP) -l xml $$(PRIVATE_INPUT_DEX_FILES) > $$@.tmp
+	$$(call commit-change-for-toc,$$@)
+endef
+
+## Define a rule which generates .dex.toc and mark it as .KATI_RESTAT.
+# $(1): The directory which contains classes*.dex files
+define define-dex-to-toc-rule
+$(eval $(call _transform-dex-to-toc,$1))\
+$(eval .KATI_RESTAT: $1/classes.dex.toc)
+endef
+
+else
+
+# Turn off .toc optimization for apps build as we cannot build dexdump.
+define define-dex-to-toc-rule
+endef
+
+endif  # TARGET_BUILD_APPS
+
 
 # Invoke Jack to compile java from source to jack files without shrink or obfuscation.
 #

core/java.mk

@@ -658,6 +658,11 @@ $(full_classes_jack): $(jack_all_deps)
 	@echo Building with Jack: $@
 	$(java-to-jack)
 
+# Update timestamps of .toc files for static java libraries so
+# dependents will be always rebuilt.
+$(built_dex).toc: $(full_classes_jack)
+	touch $@
+
 else #LOCAL_IS_STATIC_JAVA_LIBRARY
 $(built_dex_intermediate): PRIVATE_CLASSES_JACK := $(full_classes_jack)
 
@@ -671,6 +676,8 @@ $(built_dex_intermediate): $(jack_all_deps)
 $(full_classes_jack): $(built_dex_intermediate)
 	$(hide) touch $@
 
+$(call define-dex-to-toc-rule, $(intermediates.COMMON))
+
 endif #LOCAL_IS_STATIC_JAVA_LIBRARY
 
 $(noshrob_classes_jack): PRIVATE_JACK_INTERMEDIATES_DIR := $(intermediates.COMMON)/jack-noshrob-rsc

core/java_common.mk

@@ -293,6 +293,10 @@ $(LOCAL_INTERMEDIATE_TARGETS): PRIVATE_BOOTCLASSPATH_JAVA_LIBRARIES := $(my_boot
 
 full_shared_jack_libs := $(call jack-lib-files,$(LOCAL_JAVA_LIBRARIES),$(LOCAL_IS_HOST_MODULE))
 full_jack_lib_deps := $(call jack-lib-deps,$(LOCAL_JAVA_LIBRARIES),$(LOCAL_IS_HOST_MODULE))
+# Turn off .toc optimization for apps build as we cannot build dexdump.
+ifeq (,$(TARGET_BUILD_APPS))
+full_jack_lib_deps := $(patsubst %.jack, %.dex.toc, $(full_jack_lib_deps))
+endif
 
 else # LOCAL_IS_HOST_MODULE
 

core/prebuilt_internal.mk

@@ -328,6 +328,11 @@ $(intermediates.COMMON)/classes.jack : $(my_src_jar) $(LOCAL_MODULE_MAKEFILE_DEP
         $(LOCAL_ADDITIONAL_DEPENDENCIES) $(JILL_JAR) $(JACK)
 	$(transform-jar-to-jack)
 
+# Update timestamps of .toc files for prebuilts so dependents will be
+# always rebuilt.
+$(intermediates.COMMON)/classes.dex.toc: $(intermediates.COMMON)/classes.jack
+	touch $@
+
 endif # JAVA_LIBRARIES
 
 $(built_module) : $(LOCAL_MODULE_MAKEFILE_DEP) $(LOCAL_ADDITIONAL_DEPENDENCIES)