Switch host builds to use Clang by default.

If LOCAL_CLANG is not set to false for a host module, clang will be used instead of gcc.

This also enables the integrated assembler by default for Darwin host builds.

bug 16172793

Change-Id: If7484c5dbcccce7d925bec97bff0a3e4c30e9434
diff --git a/CleanSpec.mk b/CleanSpec.mk
index 7b317e2..fef406c 100644
--- a/CleanSpec.mk
+++ b/CleanSpec.mk
@@ -244,6 +244,9 @@
 # dalvik.vm.image-dex2oat-Xms, and dalvik.vm.image-dex2oat-Xmx
 $(call add-clean-step, rm -rf $(PRODUCT_OUT)/root/default.prop)
 $(call add-clean-step, rm -rf $(PRODUCT_OUT)/recovery/root/default.prop)
+
+# Switch host builds to Clang by default
+$(call add-clean-step, rm -rf $(OUT_DIR)/host)
 # ************************************************
 # NEWER CLEAN STEPS MUST BE AT THE END OF THE LIST
 # ************************************************
diff --git a/core/binary.mk b/core/binary.mk
index e843435..ac7e14f 100644
--- a/core/binary.mk
+++ b/core/binary.mk
@@ -130,6 +130,14 @@
 my_clang := $(LOCAL_CLANG_$($(my_prefix)$(LOCAL_2ND_ARCH_VAR_PREFIX)ARCH))
 endif
 
+# clang is enabled by default for host builds
+# enable it unless we've specifically disabled clang above
+ifdef LOCAL_IS_HOST_MODULE
+ifeq ($(my_clang),)
+    my_clang := true
+endif
+endif
+
 # arch-specific static libraries go first so that generic ones can depend on them
 my_static_libraries := $(LOCAL_STATIC_LIBRARIES_$($(my_prefix)$(LOCAL_2ND_ARCH_VAR_PREFIX)ARCH)) $(LOCAL_STATIC_LIBRARIES_$(my_32_64_bit_suffix)) $(my_static_libraries)
 my_whole_static_libraries := $(LOCAL_WHOLE_STATIC_LIBRARIES_$($(my_prefix)$(LOCAL_2ND_ARCH_VAR_PREFIX)ARCH)) $(LOCAL_WHOLE_STATIC_LIBRARIES_$(my_32_64_bit_suffix)) $(my_whole_static_libraries)
diff --git a/core/clang/HOST_x86.mk b/core/clang/HOST_x86.mk
index 510a74d..fb5cbf4 100644
--- a/core/clang/HOST_x86.mk
+++ b/core/clang/HOST_x86.mk
@@ -11,6 +11,10 @@
 endif
 ifeq ($(HOST_OS),darwin)
 CLANG_CONFIG_x86_HOST_TRIPLE := i686-apple-darwin
+CLANG_CONFIG_x86_HOST_COMBO_EXTRA_ASFLAGS := $(CLANG_CONFIG_x86_DARWIN_HOST_EXTRA_ASFLAGS)
+CLANG_CONFIG_x86_HOST_COMBO_EXTRA_CFLAGS := $(CLANG_CONFIG_x86_DARWIN_HOST_EXTRA_CFLAGS)
+CLANG_CONFIG_x86_HOST_COMBO_EXTRA_CPPFLAGS := $(CLANG_CONFIG_x86_DARWIN_HOST_EXTRA_CPPFLAGS)
+CLANG_CONFIG_x86_HOST_COMBO_EXTRA_LDFLAGS := $(CLANG_CONFIG_x86_DARWIN_HOST_EXTRA_LDFLAGS)
 endif
 ifeq ($(HOST_OS),windows)
 CLANG_CONFIG_x86_HOST_TRIPLE := i686-pc-mingw32
diff --git a/core/clang/HOST_x86_64.mk b/core/clang/HOST_x86_64.mk
index 6b94525..5f70678 100644
--- a/core/clang/HOST_x86_64.mk
+++ b/core/clang/HOST_x86_64.mk
@@ -11,6 +11,10 @@
 endif
 ifeq ($(HOST_OS),darwin)
 CLANG_CONFIG_x86_64_HOST_TRIPLE := x86_64-apple-darwin
+CLANG_CONFIG_x86_64_HOST_COMBO_EXTRA_ASFLAGS := $(CLANG_CONFIG_x86_DARWIN_HOST_EXTRA_ASFLAGS)
+CLANG_CONFIG_x86_64_HOST_COMBO_EXTRA_CFLAGS := $(CLANG_CONFIG_x86_DARWIN_HOST_EXTRA_CFLAGS)
+CLANG_CONFIG_x86_64_HOST_COMBO_EXTRA_CPPFLAGS := $(CLANG_CONFIG_x86_DARWIN_HOST_EXTRA_CPPFLAGS)
+CLANG_CONFIG_x86_64_HOST_COMBO_EXTRA_LDFLAGS := $(CLANG_CONFIG_x86_DARWIN_HOST_EXTRA_LDFLAGS)
 endif
 ifeq ($(HOST_OS),windows)
 CLANG_CONFIG_x86_64_HOST_TRIPLE := x86_64-pc-mingw64
diff --git a/core/clang/HOST_x86_common.mk b/core/clang/HOST_x86_common.mk
index 0241cb6..8820854 100644
--- a/core/clang/HOST_x86_common.mk
+++ b/core/clang/HOST_x86_common.mk
@@ -1,7 +1,11 @@
 # Shared by HOST_x86.mk and HOST_x86_64.mk.
 
 ifeq ($(HOST_OS),darwin)
-# nothing required here yet
+CLANG_CONFIG_x86_DARWIN_HOST_EXTRA_ASFLAGS := \
+  -integrated-as
+
+CLANG_CONFIG_x86_DARWIN_HOST_EXTRA_CFLAGS := \
+  -integrated-as
 endif
 
 ifeq ($(HOST_OS),linux)
diff --git a/core/clang/config.mk b/core/clang/config.mk
index f50a0cb..59cb38e 100644
--- a/core/clang/config.mk
+++ b/core/clang/config.mk
@@ -41,7 +41,8 @@
   -Wmaybe-uninitialized \
   -Wno-maybe-uninitialized \
   -Wno-error=maybe-uninitialized \
-  -fno-canonical-system-headers
+  -fno-canonical-system-headers \
+  -Wno-unused-local-typedefs
 
 # Clang flags for all host rules
 CLANG_CONFIG_HOST_EXTRA_ASFLAGS :=