rust: refactor --emit to be used as needed, instead of globally

Signed-off-by: Miguel Ojeda <ojeda@kernel.org>

Author: ojeda

Makefile

@@ -533,7 +533,7 @@ KBUILD_CFLAGS   := -Wall -Wundef -Werror=strict-prototypes -Wno-trigraphs \
 		   -std=gnu89
 KBUILD_CPPFLAGS := -D__KERNEL__
 KBUILD_RUST_TARGET := $(srctree)/arch/$(SRCARCH)/rust/target.json
-KBUILD_RUSTFLAGS := --emit=dep-info,obj,metadata --edition=2021 \
+KBUILD_RUSTFLAGS := --edition=2021 \
 		     -Cpanic=abort -Cembed-bitcode=n -Clto=n -Crpath=n \
 		     -Cforce-unwind-tables=n -Ccodegen-units=1 \
 		     -Zbinary_dep_depinfo=y -Zsymbol-mangling-version=v0 \

rust/Makefile

@@ -44,7 +44,7 @@ quiet_cmd_rustdoc = RUSTDOC $(if $(rustdoc_host),H, ) $<
       cmd_rustdoc = \
 	OBJTREE=$(abspath $(objtree)) \
 	$(RUSTDOC) $(if $(rustdoc_host),,$(rust_cross_flags)) \
-		$(filter-out -Cpanic=abort, $(filter-out --emit=%, $(rust_flags))) \
+		$(filter-out -Cpanic=abort, $(rust_flags)) \
 		$(rustc_target_flags) -L $(objtree)/rust \
 		--output $(objtree)/rust/doc --crate-name $(subst rustdoc-,,$@) \
 		@$(objtree)/include/generated/rustc_cfg $<
@@ -83,7 +83,7 @@ rustdoc-kernel: $(srctree)/rust/kernel/lib.rs rustdoc-core \
 quiet_cmd_rustc_test_library = RUSTC TL $<
       cmd_rustc_test_library = \
 	OBJTREE=$(abspath $(objtree)) \
-	$(RUSTC) $(filter-out --sysroot=%, $(filter-out -Cpanic=abort, $(filter-out --emit=%, $(rust_flags)))) \
+	$(RUSTC) $(filter-out --sysroot=%, $(filter-out -Cpanic=abort, $(rust_flags))) \
 		$(rustc_target_flags) --crate-type $(if $(rustc_test_library_proc),proc-macro,rlib) \
 		--out-dir $(objtree)/rust/test/ --cfg testlib \
 		--sysroot $(objtree)/rust/test/sysroot \
@@ -100,7 +100,7 @@ rusttestlib-macros: $(srctree)/rust/macros/lib.rs rusttest-prepare FORCE
 quiet_cmd_rustdoc_test = RUSTDOC T $<
       cmd_rustdoc_test = \
 	OBJTREE=$(abspath $(objtree)) \
-	$(RUSTDOC) --test $(filter-out --sysroot=%, $(filter-out -Cpanic=abort, $(filter-out --emit=%, $(rust_flags)))) \
+	$(RUSTDOC) --test $(filter-out --sysroot=%, $(filter-out -Cpanic=abort, $(rust_flags))) \
 		$(rustc_target_flags) $(rustdoc_test_target_flags) \
 		--sysroot $(objtree)/rust/test/sysroot $(rustdoc_test_quiet) \
 		-L $(objtree)/rust/test \
@@ -112,7 +112,7 @@ quiet_cmd_rustdoc_test = RUSTDOC T $<
 quiet_cmd_rustc_test = RUSTC T  $<
       cmd_rustc_test = \
 	OBJTREE=$(abspath $(objtree)) \
-	$(RUSTC) --test $(filter-out --sysroot=%, $(filter-out -Cpanic=abort, $(filter-out --emit=%, $(rust_flags)))) \
+	$(RUSTC) --test $(filter-out --sysroot=%, $(filter-out -Cpanic=abort, $(rust_flags))) \
 		$(rustc_target_flags) --out-dir $(objtree)/rust/test \
 		--sysroot $(objtree)/rust/test/sysroot \
 		-L $(objtree)/rust/test/ --crate-name $(subst rusttest-,,$@) $<; \
@@ -299,6 +299,7 @@ quiet_cmd_rustc_library = $(if $(skip_clippy),RUSTC,$(RUSTC_OR_CLIPPY_QUIET)) L
 	OBJTREE=$(abspath $(objtree)) \
 	$(if $(skip_clippy),$(RUSTC),$(RUSTC_OR_CLIPPY)) \
 		$(filter-out $(skip_flags),$(rust_flags) $(rust_cross_flags) $(rustc_target_flags)) \
+		--emit=dep-info,obj,metadata \
 		--crate-type rlib --out-dir $(objtree)/rust/ -L $(objtree)/rust/ \
 		--crate-name $(patsubst %.o,%,$(notdir $@)) $<; \
 	mv $(objtree)/rust/$(patsubst %.o,%,$(notdir $@)).d $(depfile); \

scripts/Makefile.build

@@ -337,6 +337,7 @@ quiet_cmd_rustc_o_rs = $(RUSTC_OR_CLIPPY_QUIET) $(quiet_modtag) $@
       cmd_rustc_o_rs = \
 	RUST_MODFILE=$(modfile) \
 	$(RUSTC_OR_CLIPPY) $(rust_flags) $(rust_cross_flags) \
+		--emit=dep-info,obj,metadata \
 		-Zallow-features=$(rust_allowed_features) \
 		-Zcrate-attr=no_std \
 		-Zcrate-attr='feature($(rust_allowed_features))' \