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$(nproc) samples/rust/rust_minimal.o samples/rust/rust_minimal.rsi \
samples/rust/rust_minimal.s samples/rust/rust_minimal.ll
[snip]
RUSTC [M] samples/rust/rust_minimal.o
RUSTC [M] samples/rust/rust_minimal.rsi
RUSTC [M] samples/rust/rust_minimal.s
RUSTC [M] samples/rust/rust_minimal.ll
mv: cannot stat 'samples/rust/rust_minimal.d': No such file or directory
make[3]: *** [scripts/Makefile.build:334: samples/rust/rust_minimal.ll] Error 1
make[3]: *** Waiting for unfinished jobs....
mv: cannot stat 'samples/rust/rust_minimal.d': No such file or directory
make[3]: *** [scripts/Makefile.build:309: samples/rust/rust_minimal.o] Error 1
mv: cannot stat 'samples/rust/rust_minimal.d': No such file or directory
make[3]: *** [scripts/Makefile.build:326: samples/rust/rust_minimal.s] Error 1
make[2]: *** [scripts/Makefile.build:504: samples/rust] Error 2
make[1]: *** [scripts/Makefile.build:504: samples] Error 2
make: *** [Makefile:2008: .] Error 2
The reason for the error is that 4 threads running in parallel creates
and renames the same file path, samples/rust/rust_minimal.d.
This does not happen when compiling C or assembly files because we
explicitly specify the dependency filename by using the preprocessor
option, -Wp,-MMD,$(depfile). $(depfile) is a unique path for each target.
Currently, rustc is only given --out-dir and the list of emitted types.
So, all the rust build rules output the dep-info into the default
<CRATE_NAME>.d, causing the conflict.
Fortunately, the --emit option is able to specify the output path
individually, with the form --emit=<type>=<path>.
Add --emit=dep-info=$(depfile) to the common command part. Also, remove
the redundant --out-dir because we specify the output path for each type.
The code gets much cleaner because we do not need to rename *.d files.
Signed-off-by: Masahiro Yamada <masahiroy@xxxxxxxxxx>
---
rust/Makefile | 10 ++++------
scripts/Makefile.build | 14 +++++++-------
scripts/Makefile.host | 9 +++------
3 files changed, 14 insertions(+), 19 deletions(-)
diff --git a/rust/Makefile b/rust/Makefile
index ff70c4c916f8..0e2a32f4b3e9 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 +347,9 @@ 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 da133780b751..4434cdbf7b8e 100644
--- a/scripts/Makefile.host
+++ b/scripts/Makefile.host
@@ -84,8 +84,8 @@ _hostc_flags = $(KBUILD_HOSTCFLAGS) $(HOST_EXTRACFLAGS) \
$(HOSTCFLAGS_$(target-stem).o)
_hostcxx_flags = $(KBUILD_HOSTCXXFLAGS) $(HOST_EXTRACXXFLAGS) \
$(HOSTCXXFLAGS_$(target-stem).o)
-_hostrust_flags = $(KBUILD_HOSTRUSTFLAGS) $(HOST_EXTRARUSTFLAGS) \
- $(HOSTRUSTFLAGS_$(target-stem))
+hostrust_flags = $(KBUILD_HOSTRUSTFLAGS) $(HOST_EXTRARUSTFLAGS) \
+ $(HOSTRUSTFLAGS_$(target-stem)) --emit=dep-info=$(depfile)
# $(objtree)/$(obj) for including generated headers from checkin source files
ifeq ($(KBUILD_EXTMOD),)
@@ -97,7 +97,6 @@ endif
hostc_flags = -Wp,-MMD,$(depfile) $(_hostc_flags)
hostcxx_flags = -Wp,-MMD,$(depfile) $(_hostcxx_flags)
-hostrust_flags = $(_hostrust_flags)
#####
# Compile programs on the host
@@ -149,9 +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)
--
2.34.1
