am 63082eab: am b6874440: Merge "Add support for a partial ubsan build."

* commit '63082eab1f1e18b06882fbbaf08ee64c3f68193a':
  Add support for a partial ubsan build.

core/clang/config.mk

@@ -98,6 +98,32 @@ CLANG_CONFIG_TARGET_EXTRA_CFLAGS := -nostdlibinc
 CLANG_CONFIG_TARGET_EXTRA_CPPFLAGS := -nostdlibinc
 CLANG_CONFIG_TARGET_EXTRA_LDFLAGS :=
 
+CLANG_DEFAULT_UB_CHECKS := \
+  bool \
+  integer-divide-by-zero \
+  return \
+  returns-nonnull-attribute \
+  shift-exponent \
+  unreachable \
+  vla-bound \
+
+# TODO(danalbert): The following checks currently have compiler performance
+# issues.
+# CLANG_DEFAULT_UB_CHECKS += alignment
+# CLANG_DEFAULT_UB_CHECKS += bounds
+# CLANG_DEFAULT_UB_CHECKS += enum
+# CLANG_DEFAULT_UB_CHECKS += float-cast-overflow
+# CLANG_DEFAULT_UB_CHECKS += float-divide-by-zero
+# CLANG_DEFAULT_UB_CHECKS += nonnull-attribute
+# CLANG_DEFAULT_UB_CHECKS += null
+# CLANG_DEFAULT_UB_CHECKS += shift-base
+# CLANG_DEFAULT_UB_CHECKS += signed-integer-overflow
+
+# TODO(danalbert): Fix UB in libc++'s __tree so we can turn this on.
+# https://llvm.org/PR19302
+# http://reviews.llvm.org/D6974
+# CLANG_DEFAULT_UB_CHECKS += object-size
+
 # HOST config
 clang_2nd_arch_prefix :=
 include $(BUILD_SYSTEM)/clang/HOST_$(HOST_ARCH).mk

core/config_sanitizers.mk

@@ -50,11 +50,15 @@ ifneq ($(my_clang),true)
   endif
 endif
 
-unknown_sanitizers := $(filter-out address, \
-                      $(filter-out undefined,$(my_sanitize)))
+ifneq ($(filter default-ub,$(my_sanitize)),)
+  my_sanitize := $(CLANG_DEFAULT_UB_CHECKS)
+  my_ldlibs += -ldl
 
-ifneq ($(unknown_sanitizers),)
-  $(error Unknown sanitizers: $(unknown_sanitizers))
+  ifdef LOCAL_IS_HOST_MODULE
+    my_cflags += -fno-sanitize-recover=all
+  else
+    my_cflags += -fsanitize-undefined-trap-on-error
+  endif
 endif
 
 ifneq ($(my_sanitize),)