Enable CC (ART_USE_READ_BARRIER) by default.

Bug: 34084559
Bug: 12687968
Test: boot on angler
Test: test-art-host
Change-Id: I0287b813335b472dd59aa6b94aeeab2da60b9c99
diff --git a/build/Android.common_build.mk b/build/Android.common_build.mk
index 4c82506..f5a95fa 100644
--- a/build/Android.common_build.mk
+++ b/build/Android.common_build.mk
@@ -46,6 +46,9 @@
 $(info Disabling ART_BUILD_HOST_DEBUG)
 endif
 
+# Enable the read barrier by default.
+ART_USE_READ_BARRIER ?= true
+
 ART_CPP_EXTENSION := .cc
 
 ifndef LIBART_IMG_HOST_BASE_ADDRESS
diff --git a/build/art.go b/build/art.go
index e6e0544..84269c3 100644
--- a/build/art.go
+++ b/build/art.go
@@ -58,7 +58,7 @@
 		asflags = append(asflags, "-DART_HEAP_POISONING=1")
 	}
 
-	if envTrue(ctx, "ART_USE_READ_BARRIER") || ctx.AConfig().ArtUseReadBarrier() {
+	if !envFalse(ctx, "ART_USE_READ_BARRIER") || ctx.AConfig().ArtUseReadBarrier() {
 		// Used to change the read barrier type. Valid values are BAKER, BROOKS, TABLELOOKUP.
 		// The default is BAKER.
 		barrierType := envDefault(ctx, "ART_READ_BARRIER_TYPE", "BAKER")
diff --git a/runtime/oat.h b/runtime/oat.h
index 3b3ab5a..953b445 100644
--- a/runtime/oat.h
+++ b/runtime/oat.h
@@ -32,7 +32,7 @@
 class PACKED(4) OatHeader {
  public:
   static constexpr uint8_t kOatMagic[] = { 'o', 'a', 't', '\n' };
-  static constexpr uint8_t kOatVersion[] = { '1', '0', '1', '\0' };  // Array entrypoints change
+  static constexpr uint8_t kOatVersion[] = { '1', '0', '2', '\0' };  // Enabling CC
 
   static constexpr const char* kImageLocationKey = "image-location";
   static constexpr const char* kDex2OatCmdLineKey = "dex2oat-cmdline";
diff --git a/test/etc/run-test-jar b/test/etc/run-test-jar
index 5f1071f..28fa130 100755
--- a/test/etc/run-test-jar
+++ b/test/etc/run-test-jar
@@ -44,7 +44,7 @@
 SECONDARY_DEX=""
 TIME_OUT="gdb"  # "n" (disabled), "timeout" (use timeout), "gdb" (use gdb)
 # Value in seconds
-if [ "$ART_USE_READ_BARRIER" = "true" ]; then
+if [ "$ART_USE_READ_BARRIER" != "false" ]; then
   TIME_OUT_VALUE=2400  # 40 minutes.
 else
   TIME_OUT_VALUE=1200  # 20 minutes.
diff --git a/test/run-test b/test/run-test
index a913e78..9b17802 100755
--- a/test/run-test
+++ b/test/run-test
@@ -722,7 +722,7 @@
     #
     # TODO: Enable Checker when read barrier support is added to more
     # architectures (b/12687968).
-    if [ "x$ART_USE_READ_BARRIER" = xtrue ]                    \
+    if [ "x$ART_USE_READ_BARRIER" != xfalse ]                  \
        && (([ "x$host_mode" = "xyes" ]                         \
             && ! arch_supports_read_barrier "$host_arch_name") \
            || ([ "x$target_mode" = "xyes" ]                    \