On 8/16/2024 4:17 PM, Manos Pitsidianakis wrote:
On Fri, 16 Aug 2024, 11:06 Junjie Mao, <junjie....@intel.com
<mailto:junjie....@intel.com>> wrote:
On 8/15/2024 7:42 PM, Manos Pitsidianakis wrote:
> Outstanding issues
> ==================
>
> Outstanding issues that are not blocking for merge are:
>
> - Cross-compilation for aarch64 is not possible out-of-the-box because of
this bug:
> <https://github.com/rust-lang/rust/issues/125619
<https://github.com/rust-lang/rust/issues/125619>> in llvm which when
> fixed, must be ported to upstream rust's llvm fork. Since the problem
> is an extraneous symbol we could strip it with objcopy
-N|--strip-symbol
> - Adding more than one Rust device ends up with duplicate symbols from
> rust std library because we are linking as whole archives because...
> constructors are stripped by the linker otherwise :( It can be worked
> around if a single Rust library is built with all the devices as
> dependencies which is then linked to qemu. The fix is a small change
> which I will add either in a next version or when a new Rust device is
> added.
>
Hi Manos,
I also noticed that when I tried adding a second device. Some other projects
met
similar issues [1], but no clean solution seems to be available yet. The
options
are:
1) Combining all crates into one staticlib which is linked to the final
executable. That requires generating one .rs with extern crate decls of all
enabled crates. In the context of QEMU, different targets may enable
different
set of crates (e.g., some crates have arch constraints), thus one .rs for
each
target will be needed in general.
2) Linking rlibs (or emitted objects) directly with other C objects using
the C
linker. That somehow works (with some tricks) but is not officially
supported
and may break in the future.
I'm working on (1), but would like to have your thoughts and preference on
those
options.
Hello Junjie, I have also implemented (1) already (the fix I mentioned in the
cover letter). In general I'd like to do it on a standalone patch so that it can
be separated from the other changes instead of squashing it.
If you have something already too, please share here! I will send mine as a
reply to this thread when I am able. I am not familiar with meson so my version
could be lacking!
Here's my version for your reference. There are still a few places yet to be
improved:
1. Each virtual device is required to write an additional `variables: {'crate':
'crate_name'}` in dep decl. It duplicates the crate name which is already given
in the static_libary() call, "abuses" the dep variables originally for cmake or
pkg-config, but is the only way I found to include the crate name in the dep.
2. Names of variables and scripts are tentative.
diff --git a/meson.build b/meson.build
index 97f90a9a60..07401b379a 100644
--- a/meson.build
+++ b/meson.build
@@ -3879,6 +3879,8 @@ common_all = static_library('common',
dependencies: common_ss.all_dependencies())
if have_rust and have_system
+ rust_root_crate = find_program('scripts/rust_root_crate.sh')
+
rust_args += run_command(
meson.global_source_root() / 'scripts/rustc_args.py',
'--config-headers', meson.project_build_root() / 'config-host.h',
@@ -3916,6 +3918,8 @@ if have_rust and have_system
'--allowlist-file', meson.project_build_root() + '/.*'
],
)
+
+ rust_ss = ss.source_set()
subdir('rust')
endif
@@ -4013,6 +4017,28 @@ foreach target : target_dirs
arch_srcs += target_specific.sources()
arch_deps += target_specific.dependencies()
+ if have_rust and have_system
+ target_rust = rust_ss.apply(config_target, strict: false)
+ crates = []
+ foreach dep : target_rust.dependencies()
+ crates += dep.get_variable('crate')
+ endforeach
+ if crates.length() > 0
+ root_crate = custom_target('rust-' + target + '.rs',
+ output: 'rust-' + target + '.rs',
+ command: [rust_root_crate] + crates,
+ capture: true,
+ build_by_default: true,
+ build_always_stale: true)
+ rust_lib = static_library('rust-' + target,
+ root_crate,
+ dependencies: target_rust.dependencies(),
+ rust_abi: 'c')
+ arch_deps += declare_dependency(link_whole: [rust_lib])
+ endif
+ endif
+
# allow using headers from the dependencies but do not include the sources,
# because this emulator only needs those in "objects". For external
# dependencies, the full dependency is included below in the executable.
diff --git a/rust/hw/char/pl011/meson.build b/rust/hw/char/pl011/meson.build
index 518d4924a9..55d68ffb5c 100644
--- a/rust/hw/char/pl011/meson.build
+++ b/rust/hw/char/pl011/meson.build
@@ -8,7 +8,7 @@ _libpl011_rs = static_library(
'pl011',
files('src/lib.rs'),
override_options: ['rust_std=2021', 'build.rust_std=2021'],
- rust_abi: 'c',
+ rust_abi: 'rust',
dependencies: [
bilge_dep,
bilge_impl_dep,
@@ -16,6 +16,7 @@ _libpl011_rs = static_library(
],
)
-specific_ss.add(when: 'CONFIG_X_PL011_RUST', if_true: [declare_dependency(
+rust_ss.add(when: 'CONFIG_X_PL011_RUST', if_true: [declare_dependency(
link_whole: [_libpl011_rs],
+ variables: {'crate': 'pl011'},
)])
diff --git a/scripts/rust_root_crate.sh b/scripts/rust_root_crate.sh
new file mode 100755
index 0000000000..46d7e8728a
--- /dev/null
+++ b/scripts/rust_root_crate.sh
@@ -0,0 +1,12 @@
+#!/bin/sh
+
+set -eu
+
+cat <<EOF
+/* This file is autogenerated by scripts/rust_root_crate.sh. */
+
+EOF
+
+for crate in $*; do
+ echo "extern crate $crate;"
+done
---
Best Regards
Junjie Mao
Manos
[1] https://github.com/rust-lang/rust/issues/73632
<https://github.com/rust-lang/rust/issues/73632>
---
Best Regards
Junjie Mao
