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kbuild: rust: avoid creating temporary files

PATCH In review Miguel Ojeda 3 participants 3 messages Jul 23, 2023 – Jul 25, 2023

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Miguel Ojeda

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#0 lore raw

PATCH v2 1/1 kbuild: rust: avoid creating temporary files

rustc outputs by default the temporary files (i.e. the ones saved by -Csave-temps, such as *.rcgu* files) in the current working directory when -o and --out-dir are not given (even if --emit=x=path is given, i.e. it does not use those for temporaries).

Since out-of-tree modules are compiled from the linux tree, rustc then tries to create them there, which may not be accessible.

Thus pass --out-dir explicitly, even if it is just for the temporary files.

Similarly, do so for Rust host programs too.

---
v2:
- Add fix for host programs too (Masahiro).

 scripts/Makefile.build | 5 ++++-
 scripts/Makefile.host  | 6 +++++-
 2 files changed, 9 insertions(+), 2 deletions(-)
scripts/Makefile.build +4 -1
index 6413342a03f4..82e3fb19fdaf 100644
@@ -264,6 +264,9 @@ $(obj)/%.lst: $(src)/%.c FORCE
 
 rust_allowed_features := new_uninit
 
+# `--out-dir` is required to avoid temporaries being created by `rustc` in the
+# current working directory, which may be not accessible in the out-of-tree
+# modules case.
 rust_common_cmd = \
 	RUST_MODFILE=$(modfile) $(RUSTC_OR_CLIPPY) $(rust_flags) \
 	-Zallow-features=$(rust_allowed_features) \
@@ -272,7 +275,7 @@ rust_common_cmd = \
 	--extern alloc --extern kernel \
 	--crate-type rlib -L $(objtree)/rust/ \
 	--crate-name $(basename $(notdir $@)) \
-	--emit=dep-info=$(depfile)
+	--out-dir $(dir $@) --emit=dep-info=$(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
scripts/Makefile.host +5 -1
index 7aea9005e497..8f7f842b54f9 100644
@@ -86,7 +86,11 @@ hostc_flags    = -Wp,-MMD,$(depfile) \
 hostcxx_flags  = -Wp,-MMD,$(depfile) \
                  $(KBUILD_HOSTCXXFLAGS) $(HOST_EXTRACXXFLAGS) \
                  $(HOSTCXXFLAGS_$(target-stem).o)
-hostrust_flags = --emit=dep-info=$(depfile) \
+
+# `--out-dir` is required to avoid temporaries being created by `rustc` in the
+# current working directory, which may be not accessible in the out-of-tree
+# modules case.
+hostrust_flags = --out-dir $(dir $@) --emit=dep-info=$(depfile) \
                  $(KBUILD_HOSTRUSTFLAGS) $(HOST_EXTRARUSTFLAGS) \
                  $(HOSTRUSTFLAGS_$(target-stem))
 

base-commit: 06c2afb862f9da8dc5efa4b6076a0e48c3fbaaa5

Signature · 1 line
2.41.0
Tested-by on v2 1/1
#1 lore raw
Quoted 21 lines · Miguel Ojeda

rustc outputs by default the temporary files (i.e. the ones saved by -Csave-temps, such as *.rcgu* files) in the current working directory when -o and --out-dir are not given (even if --emit=x=path is given, i.e. it does not use those for temporaries).

Since out-of-tree modules are compiled from the linux tree, rustc then tries to create them there, which may not be accessible.

Thus pass --out-dir explicitly, even if it is just for the temporary files.

Similarly, do so for Rust host programs too.

Quoted 2 lines

---
[...]

#2 lore raw
In reply to Miguel Ojeda
Quoted 22 lines · Miguel Ojeda

rustc outputs by default the temporary files (i.e. the ones saved by -Csave-temps, such as *.rcgu* files) in the current working directory when -o and --out-dir are not given (even if --emit=x=path is given, i.e. it does not use those for temporaries).

Since out-of-tree modules are compiled from the linux tree, rustc then tries to create them there, which may not be accessible.

Thus pass --out-dir explicitly, even if it is just for the temporary files.

Similarly, do so for Rust host programs too.

Quoted 3 lines

---
v2:
- Add fix for host programs too (Masahiro).

This is now available in the mainline.

df01b7cfcef08bf3fdcac2909d0e1910781d6bfd

Signature · 2 lines
Best Regards
Masahiro Yamada