[PATCH 6.1 019/236] kbuild: specify output names separately for each emission type from rustc

Greg Kroah-Hartman
2024-05-14T11:29:42Z

From: Masahiro Yamada <masahiroy@kernel.org>

[ Upstream commit 295d8398c67e314d99bb070f38883f83fe94a97a ]

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>
Stable-dep-of: ded103c7eb23 ("kbuild: rust: force `alloc` extern to allow "empty" Rust files")
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
rust/Makefile | 11 +++++------
scripts/Makefile.build | 14 +++++++-------
scripts/Makefile.host | 7 +++----
3 files changed, 15 insertions(+), 17 deletions(-)

diff --git a/rust/Makefile b/rust/Makefile
index 7700d3853404e..6d0c0e9757f21 100644
--- a/rust/Makefile
+++ b/rust/Makefile
@@ -322,10 +322,9 @@ $(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.
@@ -339,10 +338,10 @@ 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 41f3602fc8de7..9ae02542b9389 100644
--- a/scripts/Makefile.build
+++ b/scripts/Makefile.build
@@ -283,11 +283,11 @@ 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
@@ -300,7 +300,7 @@ 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
@@ -308,7 +308,7 @@ $(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)

@@ -317,7 +317,7 @@ $(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
@@ -325,7 +325,7 @@ $(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: $(src)/%.rs FORCE
diff --git a/scripts/Makefile.host b/scripts/Makefile.host
index 4a02b31cd1029..d812241144d44 100644
--- a/scripts/Makefile.host
+++ b/scripts/Makefile.host
@@ -86,7 +86,8 @@ hostc_flags = -Wp,-MMD,$(depfile) \
hostcxx_flags = -Wp,-MMD,$(depfile) \
$(KBUILD_HOSTCXXFLAGS) $(HOST_EXTRACXXFLAGS) \
$(HOSTCXXFLAGS_$(target-stem).o)
-hostrust_flags = $(KBUILD_HOSTRUSTFLAGS) $(HOST_EXTRARUSTFLAGS) \
+hostrust_flags = --emit=dep-info=$(depfile) \
+ $(KBUILD_HOSTRUSTFLAGS) $(HOST_EXTRARUSTFLAGS) \
$(HOSTRUSTFLAGS_$(target-stem))

# $(objtree)/$(obj) for including generated headers from checkin source files
@@ -147,9 +148,7 @@ $(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)
--
2.43.0