Preserve symlinks in the Soong prebuilt install steps for host binaries

and shared libs.

If a prebuilt module file is a symlink in the .intermediates tree it is
preserved when copied to the final install location. This preserves
symlinks to prebuilt binaries, so that they are run from their prebuilt
source location and can find libraries in relative paths from there.

Symlinks are converted to absolute, to not fail if they are relative in
the source tree.

Test: m clean && m droid dist checkbuild
  with and without the change, then compare the lists of symlinks in
  the out/ trees
Test: build/soong/soong_ui.bash --make-mode \
    TARGET_PRODUCT=crosshatch_hwasan TARGET_BUILD_VARIANT=userdebug \
    droid SANITIZE_TARGET=hwaddress \
    continuous_instrumentation_tests_api_coverage \
    continuous_native_tests device-tests platform_tests
  check that libclang_rt.hwasan_static-aarch64-android.a isn't a
  symlink in out/target/product/crosshatch/obj
Bug: 145934348
Change-Id: I7600e5b0754f8ea6cd0ffc8e1ba6d39153f182aa

core/base_rules.mk

@@ -515,7 +515,11 @@ ifneq ($(LOCAL_INSTALLED_MODULE),$(my_default_test_module))
 $(LOCAL_INSTALLED_MODULE): PRIVATE_POST_INSTALL_CMD := $(LOCAL_POST_INSTALL_CMD)
 $(LOCAL_INSTALLED_MODULE): $(LOCAL_BUILT_MODULE)
 	@echo "Install: $@"
+ifeq ($(LOCAL_MODULE_MAKEFILE),$(SOONG_ANDROID_MK))
+	$(copy-file-or-link-to-new-target)
+else
 	$(copy-file-to-new-target)
+endif
 	$(PRIVATE_POST_INSTALL_CMD)
 endif
 

core/definitions.mk

@@ -2551,6 +2551,18 @@ $(hide) rm -f $@
 $(hide) cp $< $@
 endef
 
+# The same as copy-file-to-new-target, but preserve symlinks. Symlinks are
+# converted to absolute to not break.
+define copy-file-or-link-to-new-target
+@mkdir -p $(dir $@)
+$(hide) rm -f $@
+$(hide) if [ -h $< ]; then \
+  ln -s $$(realpath $<) $@; \
+else \
+  cp $< $@; \
+fi
+endef
+
 # Copy a prebuilt file to a target location.
 define transform-prebuilt-to-target
 @echo "$($(PRIVATE_PREFIX)DISPLAY) Prebuilt: $(PRIVATE_MODULE) ($@)"
@@ -2563,6 +2575,13 @@ define transform-prebuilt-to-target-strip-comments
 $(copy-file-to-target-strip-comments)
 endef
 
+# Copy a prebuilt file to a target location, but preserve symlinks rather than
+# dereference them.
+define copy-or-link-prebuilt-to-target
+@echo "$($(PRIVATE_PREFIX)DISPLAY) Prebuilt: $(PRIVATE_MODULE) ($@)"
+$(copy-file-or-link-to-new-target)
+endef
+
 # Copy a list of files/directories to target location, with sub dir structure preserved.
 # For example $(HOST_OUT_EXECUTABLES)/aapt -> $(staging)/bin/aapt .
 # $(1): the source list of files/directories.

core/soong_cc_prebuilt.mk

@@ -142,8 +142,16 @@ ifeq ($(my_check_same_vndk_variants),true)
   $(LOCAL_BUILT_MODULE): $(same_vndk_variants_stamp)
 endif
 
+# Use copy-or-link-prebuilt-to-target for host executables and shared libraries,
+# to preserve symlinks to the source trees. They can then run directly from the
+# prebuilt directories where the linker can load their dependencies using
+# relative RUNPATHs.
 $(LOCAL_BUILT_MODULE): $(LOCAL_PREBUILT_MODULE_FILE)
+ifeq ($(LOCAL_IS_HOST_MODULE) $(if $(filter EXECUTABLES SHARED_LIBRARIES NATIVE_TESTS,$(LOCAL_MODULE_CLASS)),true,),true true)
+	$(copy-or-link-prebuilt-to-target)
+else
 	$(transform-prebuilt-to-target)
+endif
 ifneq ($(filter EXECUTABLES NATIVE_TESTS,$(LOCAL_MODULE_CLASS)),)
 	$(hide) chmod +x $@
 endif

core/soong_rust_prebuilt.mk

@@ -57,7 +57,11 @@ ifdef LOCAL_INSTALLED_MODULE
 endif
 
 $(LOCAL_BUILT_MODULE): $(LOCAL_PREBUILT_MODULE_FILE)
+ifeq ($(LOCAL_IS_HOST_MODULE) $(if $(filter EXECUTABLES SHARED_LIBRARIES NATIVE_TESTS,$(LOCAL_MODULE_CLASS)),true,),true true)
+	$(copy-or-link-prebuilt-to-target)
+else
 	$(transform-prebuilt-to-target)
+endif
 ifneq ($(filter EXECUTABLES NATIVE_TESTS,$(LOCAL_MODULE_CLASS)),)
 	$(hide) chmod +x $@
 endif