Merge pull request torvalds#646 from ojeda/single-target

ojeda · web-flow · commit 06be45c55691 · 2022-01-25T13:59:20.000+01:00
Add single target support for Rust (`.{o,i,s,ll}`)
diff --git a/.github/workflows/ci.yaml b/.github/workflows/ci.yaml
@@ -471,5 +471,19 @@ jobs:
       # Formatting
       - run: make ${{ env.MAKE_ARCH }} ${{ env.MAKE_CROSS_COMPILE }} ${{ env.MAKE_LLVM_IAS }} ${{ env.MAKE_TOOLCHAIN }} ${{ env.MAKE_OUTPUT }} ${{ env.MAKE_SYSROOT }} -j3 rustfmtcheck
 
+      # Single targets
+      - run: |
+          rm ${{ env.BUILD_DIR }}samples/rust/rust_minimal.o
+
+          make ${{ env.MAKE_ARCH }} ${{ env.MAKE_CROSS_COMPILE }} ${{ env.MAKE_LLVM_IAS }} ${{ env.MAKE_TOOLCHAIN }} ${{ env.MAKE_OUTPUT }} ${{ env.MAKE_SYSROOT }} -j3 samples/rust/rust_minimal.o
+          make ${{ env.MAKE_ARCH }} ${{ env.MAKE_CROSS_COMPILE }} ${{ env.MAKE_LLVM_IAS }} ${{ env.MAKE_TOOLCHAIN }} ${{ env.MAKE_OUTPUT }} ${{ env.MAKE_SYSROOT }} -j3 samples/rust/rust_minimal.i
+          make ${{ env.MAKE_ARCH }} ${{ env.MAKE_CROSS_COMPILE }} ${{ env.MAKE_LLVM_IAS }} ${{ env.MAKE_TOOLCHAIN }} ${{ env.MAKE_OUTPUT }} ${{ env.MAKE_SYSROOT }} -j3 samples/rust/rust_minimal.s
+          make ${{ env.MAKE_ARCH }} ${{ env.MAKE_CROSS_COMPILE }} ${{ env.MAKE_LLVM_IAS }} ${{ env.MAKE_TOOLCHAIN }} ${{ env.MAKE_OUTPUT }} ${{ env.MAKE_SYSROOT }} -j3 samples/rust/rust_minimal.ll
+
+          file ${{ env.BUILD_DIR }}samples/rust/rust_minimal.o | grep -F 'ELF'
+          grep -F '#![feature(prelude_import)]' ${{ env.BUILD_DIR }}samples/rust/rust_minimal.i
+          grep -F '.text'                       ${{ env.BUILD_DIR }}samples/rust/rust_minimal.s
+          grep -F '; ModuleID'                  ${{ env.BUILD_DIR }}samples/rust/rust_minimal.ll
+
       # View changes to ccache
       - run: ccache -s
diff --git a/Makefile b/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 \
@@ -1707,6 +1707,10 @@ help:
 	@echo  '                    (requires kernel .config; downloads external repos)'
 	@echo  '  rust-analyzer	  - Generate rust-project.json rust-analyzer support file'
 	@echo  '		    (requires kernel .config)'
+	@echo  '  dir/file.[os]   - Build specified target only'
+	@echo  '  dir/file.i      - Build macro expanded source, similar to C preprocessing'
+	@echo  '                    (run with RUSTFMT=n to skip reformatting if needed)'
+	@echo  '  dir/file.ll     - Build the LLVM assembly file'
 	@echo  ''
 	@$(if $(dtstree), \
 		echo 'Devicetree:'; \
diff --git a/rust/Makefile b/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 $(depfile); \
diff --git a/scripts/Makefile.build b/scripts/Makefile.build
@@ -333,22 +333,61 @@ rust_cross_flags := --target=$(realpath $(KBUILD_RUST_TARGET))
 
 rust_allowed_features := allocator_api,bench_black_box,concat_idents,generic_associated_types,global_asm
 
+rust_common_cmd = \
+	RUST_MODFILE=$(modfile) $(RUSTC_OR_CLIPPY) \
+	$(rust_flags) $(rust_cross_flags) \
+	-Zallow-features=$(rust_allowed_features) \
+	-Zcrate-attr=no_std \
+	-Zcrate-attr='feature($(rust_allowed_features))' \
+	--extern alloc --extern kernel \
+	--crate-type rlib --out-dir $(obj) -L $(objtree)/rust/ \
+	--crate-name $(basename $(notdir $@))
+
+rust_handle_depfile = \
+	mv $(obj)/$(basename $(notdir $@)).d $(depfile); \
+	sed -i '/^\#/d' $(depfile)
+
+# `--emit=obj`, `--emit=asm` and `--emit=llvm-ir` imply a single codegen unit
+# will be used. We explicitly request `-Ccodegen-units=1` in any case, and
+# the compiler shows a warning if it is not 1. However, if we ever stop
+# requesting it explicitly and we start using some other `--emit` that does not
+# imply it (and for which codegen is performed), then we would be out of sync,
+# i.e. the outputs we would get for the different single targets (e.g. `.ll`)
+# would not match each other.
+
 quiet_cmd_rustc_o_rs = $(RUSTC_OR_CLIPPY_QUIET) $(quiet_modtag) $@
       cmd_rustc_o_rs = \
-	RUST_MODFILE=$(modfile) \
-	$(RUSTC_OR_CLIPPY) $(rust_flags) $(rust_cross_flags) \
-		-Zallow-features=$(rust_allowed_features) \
-		-Zcrate-attr=no_std \
-		-Zcrate-attr='feature($(rust_allowed_features))' \
-		--extern alloc --extern kernel \
-		--crate-type rlib --out-dir $(obj) -L $(objtree)/rust/ \
-		--crate-name $(patsubst %.o,%,$(notdir $@)) $<; \
-	mv $(obj)/$(subst .o,,$(notdir $@)).d $(depfile); \
-	sed -i '/^\#/d' $(depfile)
+	$(rust_common_cmd) --emit=dep-info,obj,metadata $<; \
+	$(rust_handle_depfile)
 
 $(obj)/%.o: $(src)/%.rs FORCE
 	$(call if_changed_dep,rustc_o_rs)
 
+quiet_cmd_rustc_i_rs = $(RUSTC_OR_CLIPPY_QUIET) $(quiet_modtag) $@
+      cmd_rustc_i_rs = \
+	$(rust_common_cmd) --emit=dep-info -Zunpretty=expanded $< >$@; \
+	command -v $(RUSTFMT) >/dev/null && $(RUSTFMT) $@; \
+	$(rust_handle_depfile)
+
+$(obj)/%.i: $(src)/%.rs FORCE
+	$(call if_changed_dep,rustc_i_rs)
+
+quiet_cmd_rustc_s_rs = $(RUSTC_OR_CLIPPY_QUIET) $(quiet_modtag) $@
+      cmd_rustc_s_rs = \
+	$(rust_common_cmd) --emit=dep-info,asm $<; \
+	$(rust_handle_depfile)
+
+$(obj)/%.s: $(src)/%.rs FORCE
+	$(call if_changed_dep,rustc_s_rs)
+
+quiet_cmd_rustc_ll_rs = $(RUSTC_OR_CLIPPY_QUIET) $(quiet_modtag) $@
+      cmd_rustc_ll_rs = \
+	$(rust_common_cmd) --emit=dep-info,llvm-ir $<; \
+	$(rust_handle_depfile)
+
+$(obj)/%.ll: $(src)/%.rs FORCE
+	$(call if_changed_dep,rustc_ll_rs)
+
 # Compile assembler sources (.S)
 # ---------------------------------------------------------------------------
 
