Link in ASAN library if my_global_santitize is set.

* When my_global_santitize is set and requires ASAN,
  link with ASAN library even when local module is not
  instrumented with ASAN, unless the local module is
  the ASAN library itself.
* Add -Wl,--as-needed to my_ldflags for shared libraries
  so that unneeded ASAN library would not become
  a dependent of the built .so file.
* Change shared file and executable file link argument order
  so that -Wl flags will have effect on linked-in libraries.
* Remove unused ADDRESS_SANITIZER_CONFIG_EXTRA_SHARED_LIBRARIES.

BUG: 27614834

Change-Id: I4eda6003f1f24e498cba91c043dbe1fabe522686

core/clang/config.mk

@@ -167,7 +167,6 @@ endif
 ADDRESS_SANITIZER_CONFIG_EXTRA_CFLAGS := -fno-omit-frame-pointer
 ADDRESS_SANITIZER_CONFIG_EXTRA_LDFLAGS := -Wl,-u,__asan_preinit
 
-ADDRESS_SANITIZER_CONFIG_EXTRA_SHARED_LIBRARIES :=
 ADDRESS_SANITIZER_CONFIG_EXTRA_STATIC_LIBRARIES := libasan
 
 # This allows us to use the superset of functionality that compiler-rt

core/config_sanitizers.mk

@@ -100,10 +100,8 @@ ifneq ($(my_sanitize),)
   endif
 endif
 
-ifneq ($(filter address,$(my_sanitize)),)
-  # Frame pointer based unwinder in ASan requires ARM frame setup.
-  LOCAL_ARM_MODE := arm
-  my_cflags += $(ADDRESS_SANITIZER_CONFIG_EXTRA_CFLAGS)
+# If local or global modules need ASAN, add linker flags.
+ifneq ($(filter address,$(my_global_sanitize) $(my_sanitize)),)
   my_ldflags += $(ADDRESS_SANITIZER_CONFIG_EXTRA_LDFLAGS)
   ifdef LOCAL_IS_HOST_MODULE
     # -nodefaultlibs (provided with libc++) prevents the driver from linking
@@ -111,12 +109,20 @@ ifneq ($(filter address,$(my_sanitize)),)
     my_ldlibs += -lm -lpthread
     my_ldflags += -Wl,--no-as-needed
   else
-    my_cflags += -mllvm -asan-globals=0
+    # Add asan libraries unless LOCAL_MODULE is the asan library.
     # ASan runtime library must be the first in the link order.
-    my_shared_libraries := $($(LOCAL_2ND_ARCH_VAR_PREFIX)ADDRESS_SANITIZER_RUNTIME_LIBRARY) \
-                           $(my_shared_libraries) \
-                           $(ADDRESS_SANITIZER_CONFIG_EXTRA_SHARED_LIBRARIES)
-    my_static_libraries += $(ADDRESS_SANITIZER_CONFIG_EXTRA_STATIC_LIBRARIES)
+    ifeq (,$(filter $(LOCAL_MODULE),$($(LOCAL_2ND_ARCH_VAR_PREFIX)ADDRESS_SANITIZER_RUNTIME_LIBRARY)))
+      my_shared_libraries := $($(LOCAL_2ND_ARCH_VAR_PREFIX)ADDRESS_SANITIZER_RUNTIME_LIBRARY) \
+                             $(my_shared_libraries)
+    endif
+    ifeq (,$(filter $(LOCAL_MODULE),$(ADDRESS_SANITIZER_CONFIG_EXTRA_STATIC_LIBRARIES)))
+      my_static_libraries += $(ADDRESS_SANITIZER_CONFIG_EXTRA_STATIC_LIBRARIES)
+    endif
+
+    # Do not add unnecessary dependency in shared libraries.
+    ifeq ($(LOCAL_MODULE_CLASS),SHARED_LIBRARIES)
+      my_ldflags += -Wl,--as-needed
+    endif
 
     my_linker := $($(LOCAL_2ND_ARCH_VAR_PREFIX)ADDRESS_SANITIZER_LINKER)
     # Make sure linker_asan get installed.
@@ -124,6 +130,16 @@ ifneq ($(filter address,$(my_sanitize)),)
   endif
 endif
 
+# If local module needs ASAN, add compiler flags.
+ifneq ($(filter address,$(my_sanitize)),)
+  # Frame pointer based unwinder in ASan requires ARM frame setup.
+  LOCAL_ARM_MODE := arm
+  my_cflags += $(ADDRESS_SANITIZER_CONFIG_EXTRA_CFLAGS)
+  ifndef LOCAL_IS_HOST_MODULE
+    my_cflags += -mllvm -asan-globals=0
+  endif
+endif
+
 ifneq ($(filter undefined,$(my_sanitize)),)
   ifndef LOCAL_IS_HOST_MODULE
     $(error ubsan is not yet supported on the target)

core/definitions.mk

@@ -1593,10 +1593,10 @@ $(hide) $(PRIVATE_CXX) \
 	$(if $(filter true,$(NATIVE_COVERAGE)),$(PRIVATE_TARGET_COVERAGE_LIB)) \
 	$(PRIVATE_TARGET_LIBATOMIC) \
 	$(PRIVATE_TARGET_LIBGCC) \
-	$(call normalize-target-libraries,$(PRIVATE_ALL_SHARED_LIBRARIES)) \
-	-o $@ \
 	$(PRIVATE_TARGET_GLOBAL_LDFLAGS) \
 	$(PRIVATE_LDFLAGS) \
+	$(call normalize-target-libraries,$(PRIVATE_ALL_SHARED_LIBRARIES)) \
+	-o $@ \
 	$(PRIVATE_TARGET_CRTEND_SO_O) \
 	$(PRIVATE_LDLIBS)
 endef
@@ -1664,10 +1664,10 @@ $(hide) $(PRIVATE_CXX) -pie \
 	$(if $(filter true,$(NATIVE_COVERAGE)),$(PRIVATE_TARGET_COVERAGE_LIB)) \
 	$(PRIVATE_TARGET_LIBATOMIC) \
 	$(PRIVATE_TARGET_LIBGCC) \
-	$(call normalize-target-libraries,$(PRIVATE_ALL_SHARED_LIBRARIES)) \
-	-o $@ \
 	$(PRIVATE_TARGET_GLOBAL_LDFLAGS) \
 	$(PRIVATE_LDFLAGS) \
+	$(call normalize-target-libraries,$(PRIVATE_ALL_SHARED_LIBRARIES)) \
+	-o $@ \
 	$(PRIVATE_TARGET_CRTEND_O) \
 	$(PRIVATE_LDLIBS)
 endef