Merge "Remove our binary of ccache"
diff --git a/core/ccache.mk b/core/ccache.mk
index d67bce6..893c985 100644
--- a/core/ccache.mk
+++ b/core/ccache.mk
@@ -14,6 +14,21 @@
# limitations under the License.
#
+# We no longer provide a ccache prebuilt.
+#
+# Ours was old, and had a number of issues that triggered non-reproducible
+# results and other failures. Newer ccache versions may fix some of those
+# issues, but at the large scale of our build servers, we weren't seeing
+# significant performance gains from using ccache -- you end up needing very
+# good locality and/or very large caches if you're building many different
+# configurations.
+#
+# Local no-change full rebuilds were showing better results, but why not just
+# use incremental builds at that point?
+#
+# So if you still want to use ccache, continue setting USE_CCACHE, but also set
+# the CCACHE_EXEC environment variable to the path to your ccache executable.
+ifneq ($(CCACHE_EXEC),)
ifneq ($(filter-out false,$(USE_CCACHE)),)
# The default check uses size and modification time, causing false misses
# since the mtime depends when the repo was checked out
@@ -36,17 +51,11 @@
# See http://petereisentraut.blogspot.com/2011/09/ccache-and-clang-part-2.html
export CCACHE_CPP2 := true
- CCACHE_HOST_TAG := $(HOST_PREBUILT_TAG)
- ccache := prebuilts/misc/$(CCACHE_HOST_TAG)/ccache/ccache
- # Check that the executable is here.
- ccache := $(strip $(wildcard $(ccache)))
- ifdef ccache
- ifndef CC_WRAPPER
- CC_WRAPPER := $(ccache)
- endif
- ifndef CXX_WRAPPER
- CXX_WRAPPER := $(ccache)
- endif
- ccache =
+ ifndef CC_WRAPPER
+ CC_WRAPPER := $(CCACHE_EXEC)
endif
+ ifndef CXX_WRAPPER
+ CXX_WRAPPER := $(CCACHE_EXEC)
+ endif
+endif
endif