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[v2,2/7] kbuild: specify output names separately for each emission type from rustc

Message ID 20230107091820.3382134-2-masahiroy@kernel.org (mailing list archive)
State New, archived
Headers show
Series [v2,1/7] kbuild: refactor host*_flags | expand

Commit Message

Masahiro Yamada Jan. 7, 2023, 9:18 a.m. UTC
In Kbuild, two different rules must not write to the same file, but
it happens when compiling rust source files.

For example, set CONFIG_SAMPLE_RUST_MINIMAL=m and run the following:

  $ make -j$(nproc) samples/rust/rust_minimal.o samples/rust/rust_minimal.rsi \
                    samples/rust/rust_minimal.s samples/rust/rust_minimal.ll
    [snip]
    RUSTC [M] samples/rust/rust_minimal.o
    RUSTC [M] samples/rust/rust_minimal.rsi
    RUSTC [M] samples/rust/rust_minimal.s
    RUSTC [M] samples/rust/rust_minimal.ll
  mv: cannot stat 'samples/rust/rust_minimal.d': No such file or directory
  make[3]: *** [scripts/Makefile.build:334: samples/rust/rust_minimal.ll] Error 1
  make[3]: *** Waiting for unfinished jobs....
  mv: cannot stat 'samples/rust/rust_minimal.d': No such file or directory
  make[3]: *** [scripts/Makefile.build:309: samples/rust/rust_minimal.o] Error 1
  mv: cannot stat 'samples/rust/rust_minimal.d': No such file or directory
  make[3]: *** [scripts/Makefile.build:326: samples/rust/rust_minimal.s] Error 1
  make[2]: *** [scripts/Makefile.build:504: samples/rust] Error 2
  make[1]: *** [scripts/Makefile.build:504: samples] Error 2
  make: *** [Makefile:2008: .] Error 2

The reason for the error is that 4 threads running in parallel renames
the same file, samples/rust/rust_minimal.d.

This does not happen when compiling C or assembly files because
-Wp,-MMD,$(depfile) explicitly specifies the dependency filepath.
$(depfile) is a unique path for each target.

Currently, rustc is only given --out-dir and --emit=<list-of-types>
So, all the rust build rules output the dep-info into the default
<CRATE_NAME>.d, which causes the path conflict.

Fortunately, the --emit option is able to specify the output path
individually, with the form --emit=<type>=<path>.

Add --emit=dep-info=$(depfile) to the common part. Also, remove the
redundant --out-dir because the output path is specified for each type.

The code gets much cleaner because we do not need to rename *.d files.

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Reviewed-by: Miguel Ojeda <ojeda@kernel.org>
Tested-by: Miguel Ojeda <ojeda@kernel.org>
Reviewed-by: Vincenzo Palazzo <vincenzopalazzodev@gmail.com>
---

Changes in v2:
  - Wrap a too long line

 rust/Makefile          | 11 +++++------
 scripts/Makefile.build | 14 +++++++-------
 scripts/Makefile.host  |  6 ++----
 3 files changed, 14 insertions(+), 17 deletions(-)
diff mbox series

Patch

diff --git a/rust/Makefile b/rust/Makefile
index ff70c4c916f8..865afb87bc9b 100644
--- a/rust/Makefile
+++ b/rust/Makefile
@@ -331,10 +331,9 @@  $(obj)/exports_kernel_generated.h: $(obj)/kernel.o FORCE
 quiet_cmd_rustc_procmacro = $(RUSTC_OR_CLIPPY_QUIET) P $@
       cmd_rustc_procmacro = \
 	$(RUSTC_OR_CLIPPY) $(rust_common_flags) \
-		--emit=dep-info,link --extern proc_macro \
-		--crate-type proc-macro --out-dir $(objtree)/$(obj) \
+		--emit=dep-info=$(depfile) --emit=link=$@ --extern proc_macro \
+		--crate-type proc-macro \
 		--crate-name $(patsubst lib%.so,%,$(notdir $@)) $<; \
-	mv $(objtree)/$(obj)/$(patsubst lib%.so,%,$(notdir $@)).d $(depfile); \
 	sed -i '/^\#/d' $(depfile)
 
 # Procedural macros can only be used with the `rustc` that compiled it.
@@ -348,10 +347,10 @@  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) $(rustc_target_flags)) \
-		--emit=dep-info,obj,metadata --crate-type rlib \
-		--out-dir $(objtree)/$(obj) -L$(objtree)/$(obj) \
+		--emit=dep-info=$(depfile) --emit=obj=$@ \
+		--emit=metadata=$(dir $@)$(patsubst %.o,lib%.rmeta,$(notdir $@)) \
+		--crate-type rlib -L$(objtree)/$(obj) \
 		--crate-name $(patsubst %.o,%,$(notdir $@)) $<; \
-	mv $(objtree)/$(obj)/$(patsubst %.o,%,$(notdir $@)).d $(depfile); \
 	sed -i '/^\#/d' $(depfile) \
 	$(if $(rustc_objcopy),;$(OBJCOPY) $(rustc_objcopy) $@)
 
diff --git a/scripts/Makefile.build b/scripts/Makefile.build
index a0d5c6cca76d..40de20246e50 100644
--- a/scripts/Makefile.build
+++ b/scripts/Makefile.build
@@ -285,11 +285,11 @@  rust_common_cmd = \
 	-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 $@))
+	--crate-type rlib -L $(objtree)/rust/ \
+	--crate-name $(basename $(notdir $@)) \
+	--emit=dep-info=$(depfile)
 
 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
@@ -302,7 +302,7 @@  rust_handle_depfile = \
 
 quiet_cmd_rustc_o_rs = $(RUSTC_OR_CLIPPY_QUIET) $(quiet_modtag) $@
       cmd_rustc_o_rs = \
-	$(rust_common_cmd) --emit=dep-info,obj $<; \
+	$(rust_common_cmd) --emit=obj=$@ $<; \
 	$(rust_handle_depfile)
 
 $(obj)/%.o: $(src)/%.rs FORCE
@@ -310,7 +310,7 @@  $(obj)/%.o: $(src)/%.rs FORCE
 
 quiet_cmd_rustc_rsi_rs = $(RUSTC_OR_CLIPPY_QUIET) $(quiet_modtag) $@
       cmd_rustc_rsi_rs = \
-	$(rust_common_cmd) --emit=dep-info -Zunpretty=expanded $< >$@; \
+	$(rust_common_cmd) -Zunpretty=expanded $< >$@; \
 	command -v $(RUSTFMT) >/dev/null && $(RUSTFMT) $@; \
 	$(rust_handle_depfile)
 
@@ -319,7 +319,7 @@  $(obj)/%.rsi: $(src)/%.rs FORCE
 
 quiet_cmd_rustc_s_rs = $(RUSTC_OR_CLIPPY_QUIET) $(quiet_modtag) $@
       cmd_rustc_s_rs = \
-	$(rust_common_cmd) --emit=dep-info,asm $<; \
+	$(rust_common_cmd) --emit=asm=$@ $<; \
 	$(rust_handle_depfile)
 
 $(obj)/%.s: $(src)/%.rs FORCE
@@ -327,7 +327,7 @@  $(obj)/%.s: $(src)/%.rs FORCE
 
 quiet_cmd_rustc_ll_rs = $(RUSTC_OR_CLIPPY_QUIET) $(quiet_modtag) $@
       cmd_rustc_ll_rs = \
-	$(rust_common_cmd) --emit=dep-info,llvm-ir $<; \
+	$(rust_common_cmd) --emit=llvm-ir=$@ $<; \
 	$(rust_handle_depfile)
 
 $(obj)/%.ll: $(src)/%.rs FORCE
diff --git a/scripts/Makefile.host b/scripts/Makefile.host
index dea494ef55d5..67ef852712d4 100644
--- a/scripts/Makefile.host
+++ b/scripts/Makefile.host
@@ -85,7 +85,7 @@  hostc_flags    = $(KBUILD_HOSTCFLAGS) $(HOST_EXTRACFLAGS) \
 hostcxx_flags  = $(KBUILD_HOSTCXXFLAGS) $(HOST_EXTRACXXFLAGS) \
                   $(HOSTCXXFLAGS_$(target-stem).o) -Wp,-MMD,$(depfile)
 hostrust_flags = $(KBUILD_HOSTRUSTFLAGS) $(HOST_EXTRARUSTFLAGS) \
-                 $(HOSTRUSTFLAGS_$(target-stem))
+                 $(HOSTRUSTFLAGS_$(target-stem)) --emit=dep-info=$(depfile)
 
 # $(objtree)/$(obj) for including generated headers from checkin source files
 ifeq ($(KBUILD_EXTMOD),)
@@ -145,9 +145,7 @@  $(host-cxxobjs): $(obj)/%.o: $(src)/%.cc FORCE
 # host-rust -> Executable
 quiet_cmd_host-rust	= HOSTRUSTC $@
       cmd_host-rust	= \
-	$(HOSTRUSTC) $(hostrust_flags) --emit=dep-info,link \
-		--out-dir=$(obj)/ $<; \
-	mv $(obj)/$(target-stem).d $(depfile); \
+	$(HOSTRUSTC) $(hostrust_flags) --emit=link=$@ $<; \
 	sed -i '/^\#/d' $(depfile)
 $(host-rust): $(obj)/%: $(src)/%.rs FORCE
 	$(call if_changed_dep,host-rust)