Add global GCOV_PREFIX option.

When native coverage is enabled, add a global GCOV_PREFIX
environment variable specifying that gcda files be output
with path prefix /data/local/tmp.

Bug: 35635587
Test: make NATIVE_COVERAGE=true; check init.environ.rc
Change-Id: I40972aea3ca3168d0687bdc93e9d4b7b3a1071b9

rootdir/Android.mk

@@ -116,6 +116,12 @@ ifneq ($(filter address,$(SANITIZE_TARGET)),)
   EXPORT_GLOBAL_ASAN_OPTIONS := export ASAN_OPTIONS include=/system/asan.options
   LOCAL_REQUIRED_MODULES := asan.options $(ASAN_OPTIONS_FILES)
 endif
+
+EXPORT_GLOBAL_GCOV_OPTIONS :=
+ifeq ($(NATIVE_COVERAGE),true)
+  EXPORT_GLOBAL_GCOV_OPTIONS := export GCOV_PREFIX /data/misc/gcov
+endif
+
 # Put it here instead of in init.rc module definition,
 # because init.rc is conditionally included.
 #
@@ -163,6 +169,7 @@ $(LOCAL_BUILT_MODULE): $(LOCAL_PATH)/init.environ.rc.in $(bcp_dep)
 	$(hide) sed -e 's?%BOOTCLASSPATH%?$(PRODUCT_BOOTCLASSPATH)?g' $< >$@
 	$(hide) sed -i -e 's?%SYSTEMSERVERCLASSPATH%?$(PRODUCT_SYSTEM_SERVER_CLASSPATH)?g' $@
 	$(hide) sed -i -e 's?%EXPORT_GLOBAL_ASAN_OPTIONS%?$(EXPORT_GLOBAL_ASAN_OPTIONS)?g' $@
+	$(hide) sed -i -e 's?%EXPORT_GLOBAL_GCOV_OPTIONS%?$(EXPORT_GLOBAL_GCOV_OPTIONS)?g' $@
 
 bcp_md5 :=
 bcp_dep :=

rootdir/init.environ.rc.in

@@ -10,3 +10,4 @@ on init
     export BOOTCLASSPATH %BOOTCLASSPATH%
     export SYSTEMSERVERCLASSPATH %SYSTEMSERVERCLASSPATH%
     %EXPORT_GLOBAL_ASAN_OPTIONS%
+    %EXPORT_GLOBAL_GCOV_OPTIONS%

rootdir/init.rc

@@ -408,6 +408,7 @@ on post-fs-data
     mkdir /data/misc/profiles/cur 0771 system system
     mkdir /data/misc/profiles/ref 0771 system system
     mkdir /data/misc/profman 0770 system shell
+    mkdir /data/misc/gcov 0770 root root
 
     # For security reasons, /data/local/tmp should always be empty.
     # Do not place files or directories in /data/local/tmp