commit fd1e67b8ce041c96ddb8ca99a375182f50fad7a4
author Dan Willemsen <dwillemsen@google.com> Mon Jun 08 18:50:14 2020 -0700
committer Dan Willemsen <dwillemsen@google.com> Mon Jun 08 19:10:23 2020 -0700
tree d27732625b4e9b0378eb2697ca391604ea71cd34
parent 83e9cfe291c7acde13e36101bb82f66eff59a9af

More performance improvements

Instead of using `x := $(x) foo`, make sure `x` is initialized first,
then use `x += foo`.

For a aosp-master/aosp_crosshatch-userdebug build, this takes the build
from 49s to 33s (no significant difference in peak memory)

Bug: 158488548
Test: build-aosp_crosshatch.ninja is the same before/after
Change-Id: I41fb7611030dd3ba824f896a9c9eadbdd218f464

core/soong_java_prebuilt.mk

diff --git a/core/soong_java_prebuilt.mk b/core/soong_java_prebuilt.mk
index b15e7f6..e4c84e0 100644
--- a/core/soong_java_prebuilt.mk
+++ b/core/soong_java_prebuilt.mk
@@ -173,4 +173,4 @@
 		$(hide) echo $(PRIVATE_EXPORTED_SDK_LIBS) | tr ' ' '\n' > $@,\
 		$(hide) touch $@)
 
-SOONG_ALREADY_CONV := $(SOONG_ALREADY_CONV) $(LOCAL_MODULE)
+SOONG_ALREADY_CONV += $(LOCAL_MODULE)