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authorBenno Lossin <benno.lossin@proton.me>2023-08-14 08:47:28 +0000
committerMiguel Ojeda <ojeda@kernel.org>2023-08-21 14:31:49 +0200
commit674b1c7aed6082e1ce329bb3bcb49e7eb9913e79 (patch)
treeb355b218bea0e0ed855af0aa12cd3720474b2e03 /rust
parent9e49439077fe0a9aa062e682193b1f3257b314e2 (diff)
rust: init: add support for arbitrary paths in init macros
Previously only `ident` and generic types were supported in the `{try_}{pin_}init!` macros. This patch allows arbitrary path fragments, so for example `Foo::Bar` but also very complex paths such as `<Foo as Baz>::Bar::<0, i32>`. Internally this is accomplished by using `path` fragments. Due to some peculiar declarative macro limitations, we have to "forget" certain additional parsing information in the token trees. This is achieved by using the `paste!` proc macro. It does not actually modify the input, since no `[< >]` will be present in the input, so it just strips the information held by declarative macros. For example, if a declarative macro takes `$t:path` as its input, it cannot sensibly propagate this to a macro that takes `$($p:tt)*` as its input, since the `$t` token will only be considered one `tt` token for the second macro. If we first pipe the tokens through `paste!`, then it parses as expected. Suggested-by: Asahi Lina <lina@asahilina.net> Reviewed-by: Martin Rodriguez Reboredo <yakoyoku@gmail.com> Reviewed-by: Alice Ryhl <aliceryhl@google.com> Reviewed-by: Gary Guo <gary@garyguo.net> Signed-off-by: Benno Lossin <benno.lossin@proton.me> Link: https://lore.kernel.org/r/20230814084602.25699-10-benno.lossin@proton.me Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
Diffstat (limited to 'rust')
-rw-r--r--rust/kernel/init/macros.rs54
1 files changed, 35 insertions, 19 deletions
diff --git a/rust/kernel/init/macros.rs b/rust/kernel/init/macros.rs
index 9931666293fa..5f0a0bdb9896 100644
--- a/rust/kernel/init/macros.rs
+++ b/rust/kernel/init/macros.rs
@@ -1000,7 +1000,7 @@ macro_rules! __pin_data {
macro_rules! __init_internal {
(
@this($($this:ident)?),
- @typ($t:ident $(::<$($generics:ty),*>)?),
+ @typ($t:path),
@fields($($fields:tt)*),
@error($err:ty),
// Either `PinData` or `InitData`, `$use_data` should only be present in the `PinData`
@@ -1014,7 +1014,7 @@ macro_rules! __init_internal {
) => {
$crate::__init_internal!(with_update_parsed:
@this($($this)?),
- @typ($t $(::<$($generics),*>)? ),
+ @typ($t),
@fields($($fields)*),
@error($err),
@data($data, $($use_data)?),
@@ -1025,7 +1025,7 @@ macro_rules! __init_internal {
};
(
@this($($this:ident)?),
- @typ($t:ident $(::<$($generics:ty),*>)?),
+ @typ($t:path),
@fields($($fields:tt)*),
@error($err:ty),
// Either `PinData` or `InitData`, `$use_data` should only be present in the `PinData`
@@ -1039,7 +1039,7 @@ macro_rules! __init_internal {
) => {
$crate::__init_internal!(with_update_parsed:
@this($($this)?),
- @typ($t $(::<$($generics),*>)? ),
+ @typ($t),
@fields($($fields)*),
@error($err),
@data($data, $($use_data)?),
@@ -1050,7 +1050,7 @@ macro_rules! __init_internal {
};
(
@this($($this:ident)?),
- @typ($t:ident $(::<$($generics:ty),*>)?),
+ @typ($t:path),
@fields($($fields:tt)*),
@error($err:ty),
// Either `PinData` or `InitData`, `$use_data` should only be present in the `PinData`
@@ -1064,7 +1064,7 @@ macro_rules! __init_internal {
) => {
$crate::__init_internal!(
@this($($this)?),
- @typ($t $(::<$($generics),*>)? ),
+ @typ($t),
@fields($($fields)*),
@error($err),
@data($data, $($use_data)?),
@@ -1075,7 +1075,7 @@ macro_rules! __init_internal {
};
(with_update_parsed:
@this($($this:ident)?),
- @typ($t:ident $(::<$($generics:ty),*>)?),
+ @typ($t:path),
@fields($($fields:tt)*),
@error($err:ty),
// Either `PinData` or `InitData`, `$use_data` should only be present in the `PinData`
@@ -1094,7 +1094,11 @@ macro_rules! __init_internal {
// Get the data about fields from the supplied type.
let data = unsafe {
use $crate::init::__internal::$has_data;
- $t$(::<$($generics),*>)?::$get_data()
+ // Here we abuse `paste!` to retokenize `$t`. Declarative macros have some internal
+ // information that is associated to already parsed fragments, so a path fragment
+ // cannot be used in this position. Doing the retokenization results in valid rust
+ // code.
+ ::kernel::macros::paste!($t::$get_data())
};
// Ensure that `data` really is of type `$data` and help with type inference:
let init = $crate::init::__internal::$data::make_closure::<_, __InitOk, $err>(
@@ -1253,7 +1257,7 @@ macro_rules! __init_internal {
};
(make_initializer:
@slot($slot:ident),
- @type_name($t:ident),
+ @type_name($t:path),
@munch_fields(..Zeroable::zeroed() $(,)?),
@acc($($acc:tt)*),
) => {
@@ -1270,15 +1274,21 @@ macro_rules! __init_internal {
// not get executed, so it has no effect.
::core::ptr::write($slot, zeroed);
zeroed = ::core::mem::zeroed();
- ::core::ptr::write($slot, $t {
- $($acc)*
- ..zeroed
- });
+ // Here we abuse `paste!` to retokenize `$t`. Declarative macros have some internal
+ // information that is associated to already parsed fragments, so a path fragment
+ // cannot be used in this position. Doing the retokenization results in valid rust
+ // code.
+ ::kernel::macros::paste!(
+ ::core::ptr::write($slot, $t {
+ $($acc)*
+ ..zeroed
+ });
+ );
}
};
(make_initializer:
@slot($slot:ident),
- @type_name($t:ident),
+ @type_name($t:path),
@munch_fields($(,)?),
@acc($($acc:tt)*),
) => {
@@ -1286,14 +1296,20 @@ macro_rules! __init_internal {
// Since we are in the closure that is never called, this will never get executed.
// We abuse `slot` to get the correct type inference here:
unsafe {
- ::core::ptr::write($slot, $t {
- $($acc)*
- });
+ // Here we abuse `paste!` to retokenize `$t`. Declarative macros have some internal
+ // information that is associated to already parsed fragments, so a path fragment
+ // cannot be used in this position. Doing the retokenization results in valid rust
+ // code.
+ ::kernel::macros::paste!(
+ ::core::ptr::write($slot, $t {
+ $($acc)*
+ });
+ );
}
};
(make_initializer:
@slot($slot:ident),
- @type_name($t:ident),
+ @type_name($t:path),
@munch_fields($field:ident <- $val:expr, $($rest:tt)*),
@acc($($acc:tt)*),
) => {
@@ -1306,7 +1322,7 @@ macro_rules! __init_internal {
};
(make_initializer:
@slot($slot:ident),
- @type_name($t:ident),
+ @type_name($t:path),
@munch_fields($field:ident $(: $val:expr)?, $($rest:tt)*),
@acc($($acc:tt)*),
) => {