--- libmalloc/libmalloc-521.120.7/tests/Makefile
+++ libmalloc/libmalloc-474.0.13/tests/Makefile
@@ -12,9 +12,13 @@
 #   exclude_this_file.mtrace
 EXCLUDED_TRACE_FILES :=
 
+CUSTOM_TARGETS = \
+	MALLOC_BENCH
+
 OTHER_TEST_TARGETS = \
 	$(addprefix nano-trace-replay_, $(basename $(filter-out $(EXCLUDED_TRACE_FILES), $(TRACE_FILES)))) 
 
+MALLOCBENCHTEST_DIR = $(SRCROOT)/MallocBenchTest
 BATS_PLISTS_EXTRACT = \
 	$(patsubst %,$(SYMROOT)/%.plist,$(OTHER_TEST_TARGETS))
 
@@ -25,7 +29,6 @@
 WARNING_CFLAGS := -Wno-format-invalid-specifier -Wno-format-extra-args
 OTHER_CFLAGS += \
 	-DDARWINTEST \
-	-DOS_ATOMIC_CONFIG_MEMORY_ORDER_DEPENDENCY=1 \
 	-DOS_UNFAIR_LOCK_INLINE=1 \
 	-DT_META_TAG_XZONE=T_META_TAG\(\"xzone\"\) \
 	-DT_META_TAG_XZONE_ONLY=T_META_TAG\(\"xzone_only\"\) \
@@ -49,7 +52,17 @@
 		-o $@ \
 		$(SRCROOT)/nano_trace_replay.c
 
+# For now, we only build and run MallocBench on iOS. macOS requires
+# us to adopt installAPI.
+LOWER_SDKROOT  = $(shell echo $(SDKROOT) | tr '[:upper:]' '[:lower:]')
+ifneq (, $(findstring iphoneos,$(LOWER_SDKROOT)))
+include MallocBenchTest/Makefile.malloc-bench
+BATS_PLISTS = $(BATS_PLISTS_EXTRACT) $(MALLOCBENCHTEST_DIR)/MallocBench.plist
+else
+include MallocBenchTest/Makefile.dummy
 BATS_PLISTS = $(BATS_PLISTS_EXTRACT)
+endif
+
 BATS_PLISTS += $(PROJECT_DIR)/tests/xctests/BATS.plist
 
 $(BATS_PLISTS_EXTRACT): %.plist : %
@@ -67,46 +80,33 @@
 EXCLUDED_SOURCES += tsan.c
 endif
 
-bounds_test: OTHER_CFLAGS += -fbounds-attributes
-
-malloc_msl: OTHER_CFLAGS += -F $(PRIVATE_FRAMEWORKS)
-malloc_msl: OTHER_CFLAGS += -framework MallocStackLogging
-malloc_msl: OTHER_LDFLAGS += -F $(PRIVATE_FRAMEWORKS)
-malloc_msl: OTHER_LDFLAGS += -framework MallocStackLogging
-
-malloc_with_options_test: OTHER_LDFLAGS += -F $(PRIVATE_FRAMEWORKS)
-malloc_with_options_test: OTHER_LDFLAGS += -framework ktrace
-malloc_with_options_test: OTHER_CFLAGS += -I../src
-
 madvise: OTHER_CFLAGS += -I../src
-malloc_claimed_address_tests: OTHER_CFLAGS += -I../src
-scribble_tests: OTHER_CFLAGS += -I../src
-malloc_size_test: OTHER_CFLAGS += -I../src
 
 xzone: OTHER_LDFLAGS += -ldarwintest_utils
 
 malloc_type: OTHER_CFLAGS += -ftyped-memory-operations
 
-EXCLUDED_SOURCES += malloc_type_callsite_cpp.cpp
+ifneq ($(PLATFORM),WatchOS)
+# Modify the BATS plist to run general tests again with xzone malloc enabled
+add_xzone_tests: bats.plist
+	xcrun -sdk $(SDKROOT) python3 ./add_xzone_tests.py $(SYMROOT)/bats.plist
 
-malloc_type_callsite_cpp.o: malloc_type_callsite_cpp.cpp
-	$(CXX) $(OTHER_CXXFLAGS) $(CXXFLAGS) -fno-typed-memory-operations -fno-typed-cxx-new-delete -c $< -o $(SYMROOT)/$@
+CUSTOM_TARGETS += libmalloc_debug_symlink
 
-malloc_type_callsite: malloc_type_callsite_cpp.o
-malloc_type_callsite: OTHER_CFLAGS += $(SYMROOT)/malloc_type_callsite_cpp.o
-malloc_type_callsite: OTHER_LDFLAGS += -lc++
+# Create a symlink to the debug version of the dylib that can be picked up in
+# isolation using DYLD_LIBRARY_PATH and DYLD_IMAGE_SUFFIX
+libmalloc_debug_symlink: ;
 
-# BATS test plist handling
-#  - Modify plist (add tests) to run general tests again with xzone malloc enabled
-project_test_configs: bats.plist
-	cp ./libmalloc_pgm.plist $(DSTROOT)/AppleInternal/CoreOS/BATS/unit_tests/
-	xcrun -sdk $(SDKROOT) python3 ./add_xzone_tests.py $(SYMROOT)/bats.plist --platform $(PLATFORM)
+install-libmalloc_debug_symlink:
+	mkdir -p $(INSTALLDIR)
+	ln -sf /usr/lib/system/libsystem_malloc_debug.dylib $(INSTALLDIR)/libsystem_malloc_testdebug.dylib
 
-.PHONY: project_test_configs
+.PHONY: add_xzone_tests
 
 # Ensure that we add the xzone tests before bats.plist is installed to the
 # dstroot
-install: project_test_configs
+install: add_xzone_tests
+endif # ($(PLATFORM),WatchOS)
 
 .DEFAULT_GOAL := all