Re: [PATCH] rust: query the compiler for dylib path

[Daniel Gomez]

On Wed Oct 9, 2024 at 12:48 AM CEST, Tamir Duberstein wrote:
> Rust proc-macro crates are loaded by the compiler at compile-time, so
> are always dynamic libraries; on macOS, these artifacts get a .dylib
> extension rather than .so.
>
> Replace hardcoded paths ending in .so with paths obtained from the
> compiler.
>
> Signed-off-by: Fiona Behrens <me@xxxxxxxxxx>
> Signed-off-by: Tamir Duberstein <tamird@xxxxxxxxx>
> ---
>  .gitignore                        |  1 +
>  Makefile                          |  2 +-
>  rust/Makefile                     | 21 ++++++++++++---------
>  scripts/generate_rust_analyzer.py | 16 ++++++++++++----
>  4 files changed, 26 insertions(+), 14 deletions(-)
>
> diff --git a/.gitignore b/.gitignore
> index 56972adb5031..7cfe4f70b39a 100644
> --- a/.gitignore
> +++ b/.gitignore
> @@ -22,6 +22,7 @@
>  *.dtb.S
>  *.dtbo.S
>  *.dwo
> +*.dylib
>  *.elf
>  *.gcno
>  *.gcda
> diff --git a/Makefile b/Makefile
> index c5493c0c0ca1..3808869fb95b 100644
> --- a/Makefile
> +++ b/Makefile
> @@ -1506,7 +1506,7 @@ MRPROPER_FILES += include/config include/generated          \
>  		  certs/x509.genkey \
>  		  vmlinux-gdb.py \
>  		  rpmbuild \
> -		  rust/libmacros.so
> +		  rust/libmacros.so rust/libmacros.dylib
>  
>  # clean - Delete most, but leave enough to build external modules
>  #
> diff --git a/rust/Makefile b/rust/Makefile
> index b5e0a73b78f3..a185a4d05b08 100644
> --- a/rust/Makefile
> +++ b/rust/Makefile
> @@ -11,9 +11,6 @@ always-$(CONFIG_RUST) += exports_core_generated.h
>  obj-$(CONFIG_RUST) += helpers/helpers.o
>  CFLAGS_REMOVE_helpers/helpers.o = -Wmissing-prototypes -Wmissing-declarations
>  
> -always-$(CONFIG_RUST) += libmacros.so
> -no-clean-files += libmacros.so
> -
>  always-$(CONFIG_RUST) += bindings/bindings_generated.rs bindings/bindings_helpers_generated.rs
>  obj-$(CONFIG_RUST) += alloc.o bindings.o kernel.o
>  always-$(CONFIG_RUST) += exports_alloc_generated.h exports_helpers_generated.h \
> @@ -36,9 +33,15 @@ always-$(CONFIG_RUST_KERNEL_DOCTESTS) += doctests_kernel_generated_kunit.c
>  obj-$(CONFIG_RUST_KERNEL_DOCTESTS) += doctests_kernel_generated.o
>  obj-$(CONFIG_RUST_KERNEL_DOCTESTS) += doctests_kernel_generated_kunit.o
>  
> -# Avoids running `$(RUSTC)` for the sysroot when it may not be available.
> +# Avoids running `$(RUSTC)` when it may not be available.
>  ifdef CONFIG_RUST
>  
> +libmacros_name := $($(RUSTC) --print file-names --crate-name macros --crate-type proc-macro - < /dev/null)
> +libmacros_extension := $(patsubst libmacros.%,%,$(libmacros_name))
> +
> +always-$(CONFIG_RUST) += $(libmacros_name)
> +no-clean-files += $(libmacros_name)
> +
>  # `$(rust_flags)` is passed in case the user added `--sysroot`.
>  rustc_sysroot := $(shell MAKEFLAGS= $(RUSTC) $(rust_flags) --print sysroot)
>  rustc_host_target := $(shell $(RUSTC) --version --verbose | grep -F 'host: ' | cut -d' ' -f2)
> @@ -115,10 +118,10 @@ rustdoc-alloc: $(RUST_LIB_SRC)/alloc/src/lib.rs rustdoc-core rustdoc-compiler_bu
>  	+$(call if_changed,rustdoc)
>  
>  rustdoc-kernel: private rustc_target_flags = --extern alloc \
> -    --extern build_error --extern macros=$(objtree)/$(obj)/libmacros.so \
> +    --extern build_error --extern macros=$(objtree)/$(obj)/$(libmacros_name) \
>      --extern bindings --extern uapi
>  rustdoc-kernel: $(src)/kernel/lib.rs rustdoc-core rustdoc-macros \
> -    rustdoc-compiler_builtins rustdoc-alloc $(obj)/libmacros.so \
> +    rustdoc-compiler_builtins rustdoc-alloc $(obj)/$(libmacros_name) \
>      $(obj)/bindings.o FORCE
>  	+$(call if_changed,rustdoc)
>  
> @@ -339,10 +342,10 @@ quiet_cmd_rustc_procmacro = $(RUSTC_OR_CLIPPY_QUIET) P $@
>  		-Clink-args='$(call escsq,$(KBUILD_HOSTLDFLAGS))' \
>  		--emit=dep-info=$(depfile) --emit=link=$@ --extern proc_macro \
>  		--crate-type proc-macro \
> -		--crate-name $(patsubst lib%.so,%,$(notdir $@)) $<
> +		--crate-name $(patsubst lib%.$(libmacros_extension),%,$(notdir $@)) $<
>  
>  # Procedural macros can only be used with the `rustc` that compiled it.
> -$(obj)/libmacros.so: $(src)/macros/lib.rs FORCE
> +$(obj)/$(libmacros_name): $(src)/macros/lib.rs FORCE
>  	+$(call if_changed_dep,rustc_procmacro)
>  
>  quiet_cmd_rustc_library = $(if $(skip_clippy),RUSTC,$(RUSTC_OR_CLIPPY_QUIET)) L $@
> @@ -421,7 +424,7 @@ $(obj)/uapi.o: $(src)/uapi/lib.rs \
>  $(obj)/kernel.o: private rustc_target_flags = --extern alloc \
>      --extern build_error --extern macros --extern bindings --extern uapi
>  $(obj)/kernel.o: $(src)/kernel/lib.rs $(obj)/alloc.o $(obj)/build_error.o \
> -    $(obj)/libmacros.so $(obj)/bindings.o $(obj)/uapi.o FORCE
> +    $(obj)/$(libmacros_name) $(obj)/bindings.o $(obj)/uapi.o FORCE
>  	+$(call if_changed_rule,rustc_library)
>  
>  endif # CONFIG_RUST
> diff --git a/scripts/generate_rust_analyzer.py b/scripts/generate_rust_analyzer.py
> index d2bc63cde8c6..3834ab0eea9d 100755
> --- a/scripts/generate_rust_analyzer.py
> +++ b/scripts/generate_rust_analyzer.py
> @@ -9,6 +9,8 @@ import logging
>  import os
>  import pathlib
>  import sys
> +import os
> +import subprocess

import os is duplicated.

>  
>  def args_crates_cfgs(cfgs):
>      crates_cfgs = {}
> @@ -35,8 +37,7 @@ def generate_crates(srctree, objtree, sysroot_src, external_src, cfgs):
>      crates_cfgs = args_crates_cfgs(cfgs)
>  
>      def append_crate(display_name, root_module, deps, cfg=[], is_workspace_member=True, is_proc_macro=False):
> -        crates_indexes[display_name] = len(crates)
> -        crates.append({
> +        crate = {
>              "display_name": display_name,
>              "root_module": str(root_module),
>              "is_workspace_member": is_workspace_member,
> @@ -47,7 +48,15 @@ def generate_crates(srctree, objtree, sysroot_src, external_src, cfgs):
>              "env": {
>                  "RUST_MODFILE": "This is only for rust-analyzer"
>              }
> -        })
> +        }
> +        if is_proc_macro:
> +            proc_macro_dylib_name = subprocess.check_output(
> +                [os.environ["RUSTC"], "--print", "file-names", "--crate-name", display_name, "--crate-type", "proc-macro", "-"],
> +                stdin=subprocess.DEVNULL,
> +            ).decode('utf-8')
> +            crate["proc_macro_dylib_path"] = f"{objtree}/rust/{proc_macro_dylib_name}"
> +        crates_indexes[display_name] = len(crates)
> +        crates.append(crate)
>  
>      # First, the ones in `rust/` since they are a bit special.
>      append_crate(
> @@ -77,7 +86,6 @@ def generate_crates(srctree, objtree, sysroot_src, external_src, cfgs):
>          [],
>          is_proc_macro=True,
>      )
> -    crates[-1]["proc_macro_dylib_path"] = f"{objtree}/rust/libmacros.so"
>  
>      append_crate(
>          "build_error",