Add basic musl support to make

There are still devices that set BUILD_BROKEN_USES_BUILD_HOST_* and
build host modules in Make.  Add basic support for building against
libc_musl in Make when USE_HOST_MUSL is set.

Bug: 258535366
Test: build a host tool defined in Android.mk file in internal branch
Change-Id: I9150be749bbeaac2ac5a33b2cf915004aa3033df

core/binary.mk

@@ -19,7 +19,11 @@ include $(BUILD_SYSTEM)/use_lld_setup.mk
 # supply that, for example, when building libc itself.
 ifdef LOCAL_IS_HOST_MODULE
   ifeq ($(LOCAL_SYSTEM_SHARED_LIBRARIES),none)
+    ifdef USE_HOST_MUSL
+      my_system_shared_libraries := libc_musl
+    else
       my_system_shared_libraries :=
+    endif
   else
       my_system_shared_libraries := $(LOCAL_SYSTEM_SHARED_LIBRARIES)
   endif
@@ -348,9 +352,11 @@ my_ldlibs := $(filter $(my_allowed_ldlibs),$(my_ldlibs))
 else # LOCAL_IS_HOST_MODULE
   # Add -ldl, -lpthread, -lm and -lrt to host builds to match the default behavior of
   # device builds
-  my_ldlibs += -ldl -lpthread -lm
-  ifneq ($(HOST_OS),darwin)
-    my_ldlibs += -lrt
+  ifndef USE_HOST_MUSL
+    my_ldlibs += -ldl -lpthread -lm
+    ifneq ($(HOST_OS),darwin)
+      my_ldlibs += -lrt
+    endif
   endif
 endif
 

core/config.mk

@@ -1049,14 +1049,6 @@ endif # PRODUCT_USE_DYNAMIC_PARTITIONS
 BOARD_PREBUILT_HIDDENAPI_DIR ?=
 .KATI_READONLY := BOARD_PREBUILT_HIDDENAPI_DIR
 
-ifdef USE_HOST_MUSL
-  ifneq (,$(or $(BUILD_BROKEN_USES_BUILD_HOST_EXECUTABLE),\
-               $(BUILD_BROKEN_USES_BUILD_HOST_SHARED_LIBRARY),\
-               $(BUILD_BROKEN_USES_BUILD_HOST_STATIC_LIBRARY)))
-    $(error USE_HOST_MUSL can't be set when native host builds are enabled in Make with BUILD_BROKEN_USES_BUILD_HOST_*)
-  endif
-endif
-
 # ###############################################################
 # Set up final options.
 # ###############################################################

core/definitions.mk

@@ -2121,6 +2121,7 @@ $(hide) $(PRIVATE_CXX_LINK) \
      $(PRIVATE_HOST_GLOBAL_LDFLAGS) \
   ) \
   $(PRIVATE_LDFLAGS) \
+  $(PRIVATE_CRTBEGIN) \
   $(PRIVATE_ALL_OBJECTS) \
   -Wl,--whole-archive \
   $(PRIVATE_ALL_WHOLE_STATIC_LIBRARIES) \
@@ -2129,8 +2130,10 @@ $(hide) $(PRIVATE_CXX_LINK) \
   $(PRIVATE_ALL_STATIC_LIBRARIES) \
   $(if $(PRIVATE_GROUP_STATIC_LIBRARIES),-Wl$(comma)--end-group) \
   $(if $(filter true,$(NATIVE_COVERAGE)),$(PRIVATE_HOST_LIBPROFILE_RT)) \
+  $(PRIVATE_LIBCRT_BUILTINS) \
   $(PRIVATE_ALL_SHARED_LIBRARIES) \
   -o $@ \
+  $(PRIVATE_CRTEND) \
   $(PRIVATE_LDLIBS)
 endef
 endif
@@ -2264,6 +2267,7 @@ endef
 ifneq ($(HOST_CUSTOM_LD_COMMAND),true)
 define transform-host-o-to-executable-inner
 $(hide) $(PRIVATE_CXX_LINK) \
+  $(PRIVATE_CRTBEGIN) \
   $(PRIVATE_ALL_OBJECTS) \
   -Wl,--whole-archive \
   $(PRIVATE_ALL_WHOLE_STATIC_LIBRARIES) \
@@ -2272,6 +2276,7 @@ $(hide) $(PRIVATE_CXX_LINK) \
   $(PRIVATE_ALL_STATIC_LIBRARIES) \
   $(if $(PRIVATE_GROUP_STATIC_LIBRARIES),-Wl$(comma)--end-group) \
   $(if $(filter true,$(NATIVE_COVERAGE)),$(PRIVATE_HOST_LIBPROFILE_RT)) \
+  $(PRIVATE_LIBCRT_BUILTINS) \
   $(PRIVATE_ALL_SHARED_LIBRARIES) \
   $(foreach path,$(PRIVATE_RPATHS), \
     -Wl,-rpath,\$$ORIGIN/$(path)) \
@@ -2280,6 +2285,7 @@ $(hide) $(PRIVATE_CXX_LINK) \
   ) \
   $(PRIVATE_LDFLAGS) \
   -o $@ \
+  $(PRIVATE_CRTEND) \
   $(PRIVATE_LDLIBS)
 endef
 endif

core/host_executable_internal.mk

@@ -39,6 +39,21 @@ $(LOCAL_BUILT_MODULE): PRIVATE_RPATHS := ../$(my_libdir) $(my_libdir)
 endif
 my_libdir :=
 
+my_crtbegin :=
+my_crtend :=
+my_libcrt_builtins :=
+ifdef USE_HOST_MUSL
+  my_crtbegin := $(SOONG_$(LOCAL_2ND_ARCH_VAR_PREFIX)HOST_OBJECT_libc_musl_crtbegin_dynamic)
+  my_crtend := $(SOONG_$(LOCAL_2ND_ARCH_VAR_PREFIX)HOST_OBJECT_libc_musl_crtend)
+  my_libcrt_builtins := $($(LOCAL_2ND_ARCH_VAR_PREFIX)$(my_prefix)LIBCRT_BUILTINS)
+  $(LOCAL_BUILT_MODULE): PRIVATE_LDFLAGS += -Wl,--no-dynamic-linker
+endif
+
+$(LOCAL_BUILT_MODULE): PRIVATE_CRTBEGIN := $(my_crtbegin)
+$(LOCAL_BUILT_MODULE): PRIVATE_CRTEND := $(my_crtend)
+$(LOCAL_BUILT_MODULE): PRIVATE_LIBCRT_BUILTINS := $(my_libcrt_builtins)
+$(LOCAL_BUILT_MODULE): $(my_crtbegin) $(my_crtend) $(my_libcrt_builtins)
+
 $(LOCAL_BUILT_MODULE): $(all_objects) $(all_libraries) $(CLANG_CXX)
 	$(transform-host-o-to-executable)
 

core/host_shared_library_internal.mk

@@ -36,6 +36,17 @@ include $(BUILD_SYSTEM)/binary.mk
 my_host_libprofile_rt := $($(LOCAL_2ND_ARCH_VAR_PREFIX)$(my_prefix)LIBPROFILE_RT)
 $(LOCAL_BUILT_MODULE): PRIVATE_HOST_LIBPROFILE_RT := $(my_host_libprofile_rt)
 
+ifdef USE_HOST_MUSL
+  my_crtbegin := $(SOONG_$(LOCAL_2ND_ARCH_VAR_PREFIX)HOST_OBJECT_libc_musl_crtbegin_so)
+  my_crtend := $(SOONG_$(LOCAL_2ND_ARCH_VAR_PREFIX)HOST_OBJECT_libc_musl_crtend_so)
+  my_libcrt_builtins := $($(LOCAL_2ND_ARCH_VAR_PREFIX)$(my_prefix)LIBCRT_BUILTINS)
+endif
+
+$(LOCAL_BUILT_MODULE): PRIVATE_CRTBEGIN := $(my_crtbegin)
+$(LOCAL_BUILT_MODULE): PRIVATE_CRTEND := $(my_crtend)
+$(LOCAL_BUILT_MODULE): PRIVATE_LIBCRT_BUILTINS := $(my_libcrt_builtins)
+$(LOCAL_BUILT_MODULE): $(my_crtbegin) $(my_crtend) $(my_libcrt_builtins)
+
 $(LOCAL_BUILT_MODULE): \
         $(all_objects) \
         $(all_libraries) \