2023-09-28 23:40:35

by Matthew Maurer

[permalink] [raw]
Subject: [PATCH v3] rust: Respect HOSTCC when linking for host

Currently, rustc defaults to invoking `cc`, even if `HOSTCC` is defined,
resulting in build failures in hermetic environments where `cc` does not
exist. This includes both hostprogs and proc-macros.

Since we are setting the linker to `HOSTCC`, we set the linker flavor to
`gcc` explicitly. The linker-flavor selects both which linker to search
for if the linker is unset, and which kind of linker flags to pass.
Without this flag, `rustc` would attempt to determine which flags to
pass based on the name of the binary passed as `HOSTCC`. `gcc` is the
name of the linker-flavor used by `rustc` for all C compilers, including
both `gcc` and `clang`.

Signed-off-by: Matthew Maurer <[email protected]>
---
rust/Makefile | 2 ++
scripts/Makefile.host | 2 ++
2 files changed, 4 insertions(+)

diff --git a/rust/Makefile b/rust/Makefile
index 87958e864be0..da664d7aed51 100644
--- a/rust/Makefile
+++ b/rust/Makefile
@@ -383,6 +383,8 @@ $(obj)/exports_kernel_generated.h: $(obj)/kernel.o FORCE
quiet_cmd_rustc_procmacro = $(RUSTC_OR_CLIPPY_QUIET) P $@
cmd_rustc_procmacro = \
$(RUSTC_OR_CLIPPY) $(rust_common_flags) \
+ -Clinker-flavor=gcc -Clinker=$(HOSTCC) \
+ -Clink-args='$(subst ','\'',$(KBUILD_HOSTLDFLAGS))' \
--emit=dep-info=$(depfile) --emit=link=$@ --extern proc_macro \
--crate-type proc-macro \
--crate-name $(patsubst lib%.so,%,$(notdir $@)) $<
diff --git a/scripts/Makefile.host b/scripts/Makefile.host
index 8f7f842b54f9..08d83d9db31a 100644
--- a/scripts/Makefile.host
+++ b/scripts/Makefile.host
@@ -91,6 +91,8 @@ hostcxx_flags = -Wp,-MMD,$(depfile) \
# current working directory, which may be not accessible in the out-of-tree
# modules case.
hostrust_flags = --out-dir $(dir $@) --emit=dep-info=$(depfile) \
+ -Clinker-flavor=gcc -Clinker=$(HOSTCC) \
+ -Clink-args='$(call escsq,$(KBUILD_HOSTLDFLAGS))' \
$(KBUILD_HOSTRUSTFLAGS) $(HOST_EXTRARUSTFLAGS) \
$(HOSTRUSTFLAGS_$(target-stem))

--
2.42.0.582.g8ccd20d70d-goog


Subject: Re: [PATCH v3] rust: Respect HOSTCC when linking for host

On 9/28/23 16:48, Matthew Maurer wrote:
> Currently, rustc defaults to invoking `cc`, even if `HOSTCC` is defined,
> resulting in build failures in hermetic environments where `cc` does not
> exist. This includes both hostprogs and proc-macros.
>
> Since we are setting the linker to `HOSTCC`, we set the linker flavor to
> `gcc` explicitly. The linker-flavor selects both which linker to search
> for if the linker is unset, and which kind of linker flags to pass.
> Without this flag, `rustc` would attempt to determine which flags to
> pass based on the name of the binary passed as `HOSTCC`. `gcc` is the
> name of the linker-flavor used by `rustc` for all C compilers, including
> both `gcc` and `clang`.
>
> Signed-off-by: Matthew Maurer <[email protected]>
> ---

Psst, next time I'd recommend putting patch version to version changes
here. Still, LGTM.

> [...]
Reviewed-by: Martin Rodriguez Reboredo <[email protected]>

2023-09-30 06:03:23

by Masahiro Yamada

[permalink] [raw]
Subject: Re: [PATCH v3] rust: Respect HOSTCC when linking for host

On Fri, Sep 29, 2023 at 4:48 AM Matthew Maurer <[email protected]> wrote:
>
> Currently, rustc defaults to invoking `cc`, even if `HOSTCC` is defined,
> resulting in build failures in hermetic environments where `cc` does not
> exist. This includes both hostprogs and proc-macros.
>
> Since we are setting the linker to `HOSTCC`, we set the linker flavor to
> `gcc` explicitly. The linker-flavor selects both which linker to search
> for if the linker is unset, and which kind of linker flags to pass.
> Without this flag, `rustc` would attempt to determine which flags to
> pass based on the name of the binary passed as `HOSTCC`. `gcc` is the
> name of the linker-flavor used by `rustc` for all C compilers, including
> both `gcc` and `clang`.
>
> Signed-off-by: Matthew Maurer <[email protected]>
> ---
> rust/Makefile | 2 ++
> scripts/Makefile.host | 2 ++
> 2 files changed, 4 insertions(+)
>
> diff --git a/rust/Makefile b/rust/Makefile
> index 87958e864be0..da664d7aed51 100644
> --- a/rust/Makefile
> +++ b/rust/Makefile
> @@ -383,6 +383,8 @@ $(obj)/exports_kernel_generated.h: $(obj)/kernel.o FORCE
> quiet_cmd_rustc_procmacro = $(RUSTC_OR_CLIPPY_QUIET) P $@
> cmd_rustc_procmacro = \
> $(RUSTC_OR_CLIPPY) $(rust_common_flags) \
> + -Clinker-flavor=gcc -Clinker=$(HOSTCC) \
> + -Clink-args='$(subst ','\'',$(KBUILD_HOSTLDFLAGS))' \



Why not consistently use the escsq macro here too ?






> --emit=dep-info=$(depfile) --emit=link=$@ --extern proc_macro \
> --crate-type proc-macro \
> --crate-name $(patsubst lib%.so,%,$(notdir $@)) $<
> diff --git a/scripts/Makefile.host b/scripts/Makefile.host
> index 8f7f842b54f9..08d83d9db31a 100644
> --- a/scripts/Makefile.host
> +++ b/scripts/Makefile.host
> @@ -91,6 +91,8 @@ hostcxx_flags = -Wp,-MMD,$(depfile) \
> # current working directory, which may be not accessible in the out-of-tree
> # modules case.
> hostrust_flags = --out-dir $(dir $@) --emit=dep-info=$(depfile) \
> + -Clinker-flavor=gcc -Clinker=$(HOSTCC) \
> + -Clink-args='$(call escsq,$(KBUILD_HOSTLDFLAGS))' \
> $(KBUILD_HOSTRUSTFLAGS) $(HOST_EXTRARUSTFLAGS) \
> $(HOSTRUSTFLAGS_$(target-stem))
>
> --
> 2.42.0.582.g8ccd20d70d-goog
>


--
Best Regards
Masahiro Yamada

2023-10-02 17:19:45

by Alice Ryhl

[permalink] [raw]
Subject: Re: [PATCH v3] rust: Respect HOSTCC when linking for host

On Thu, Sep 28, 2023 at 9:48 PM Matthew Maurer <[email protected]> wrote:
>
> Currently, rustc defaults to invoking `cc`, even if `HOSTCC` is defined,
> resulting in build failures in hermetic environments where `cc` does not
> exist. This includes both hostprogs and proc-macros.
>
> Since we are setting the linker to `HOSTCC`, we set the linker flavor to
> `gcc` explicitly. The linker-flavor selects both which linker to search
> for if the linker is unset, and which kind of linker flags to pass.
> Without this flag, `rustc` would attempt to determine which flags to
> pass based on the name of the binary passed as `HOSTCC`. `gcc` is the
> name of the linker-flavor used by `rustc` for all C compilers, including
> both `gcc` and `clang`.
>
> Signed-off-by: Matthew Maurer <[email protected]>

Tested-by: Alice Ryhl <[email protected]>

2023-10-05 21:36:49

by Matthew Maurer

[permalink] [raw]
Subject: Re: [PATCH v3] rust: Respect HOSTCC when linking for host

On Fri, Sep 29, 2023 at 10:59 PM Masahiro Yamada <[email protected]> wrote:
>
> On Fri, Sep 29, 2023 at 4:48 AM Matthew Maurer <[email protected]> wrote:
> >
> > Currently, rustc defaults to invoking `cc`, even if `HOSTCC` is defined,
> > resulting in build failures in hermetic environments where `cc` does not
> > exist. This includes both hostprogs and proc-macros.
> >
> > Since we are setting the linker to `HOSTCC`, we set the linker flavor to
> > `gcc` explicitly. The linker-flavor selects both which linker to search
> > for if the linker is unset, and which kind of linker flags to pass.
> > Without this flag, `rustc` would attempt to determine which flags to
> > pass based on the name of the binary passed as `HOSTCC`. `gcc` is the
> > name of the linker-flavor used by `rustc` for all C compilers, including
> > both `gcc` and `clang`.
> >
> > Signed-off-by: Matthew Maurer <[email protected]>
> > ---
> > rust/Makefile | 2 ++
> > scripts/Makefile.host | 2 ++
> > 2 files changed, 4 insertions(+)
> >
> > diff --git a/rust/Makefile b/rust/Makefile
> > index 87958e864be0..da664d7aed51 100644
> > --- a/rust/Makefile
> > +++ b/rust/Makefile
> > @@ -383,6 +383,8 @@ $(obj)/exports_kernel_generated.h: $(obj)/kernel.o FORCE
> > quiet_cmd_rustc_procmacro = $(RUSTC_OR_CLIPPY_QUIET) P $@
> > cmd_rustc_procmacro = \
> > $(RUSTC_OR_CLIPPY) $(rust_common_flags) \
> > + -Clinker-flavor=gcc -Clinker=$(HOSTCC) \
> > + -Clink-args='$(subst ','\'',$(KBUILD_HOSTLDFLAGS))' \
>
>
>
> Why not consistently use the escsq macro here too ?
>
>
I didn't use it in rust/Makefile because that makefile doesn't
directly import scripts/Kbuild.include, and I was under the mistaken
impression that scripts/ was supposed to be its own namespace, even if
Make wasn't enforcing it. Inspecting other functions in
scripts/Kbuild.include though, it's clear they're called elsewhere, so
I'll upload another version of the patch using escsq here as well.
>
>
>
>
> > --emit=dep-info=$(depfile) --emit=link=$@ --extern proc_macro \
> > --crate-type proc-macro \
> > --crate-name $(patsubst lib%.so,%,$(notdir $@)) $<
> > diff --git a/scripts/Makefile.host b/scripts/Makefile.host
> > index 8f7f842b54f9..08d83d9db31a 100644
> > --- a/scripts/Makefile.host
> > +++ b/scripts/Makefile.host
> > @@ -91,6 +91,8 @@ hostcxx_flags = -Wp,-MMD,$(depfile) \
> > # current working directory, which may be not accessible in the out-of-tree
> > # modules case.
> > hostrust_flags = --out-dir $(dir $@) --emit=dep-info=$(depfile) \
> > + -Clinker-flavor=gcc -Clinker=$(HOSTCC) \
> > + -Clink-args='$(call escsq,$(KBUILD_HOSTLDFLAGS))' \
> > $(KBUILD_HOSTRUSTFLAGS) $(HOST_EXTRARUSTFLAGS) \
> > $(HOSTRUSTFLAGS_$(target-stem))
> >
> > --
> > 2.42.0.582.g8ccd20d70d-goog
> >
>
>
> --
> Best Regards
> Masahiro Yamada