rustdoc: save target modifiers #144523

ojeda · 2025-07-27T00:05:37Z

rustdoc was filling a target_modifiers variable, but it was not using the result.

In turn, that means that trying to use a dependency that set a target modifier fails.

For instance, running:

RUSTC_BOOTSTRAP=1 rustc --edition=2024 --target=aarch64-unknown-none-softfloat --sysroot=/dev/null --emit=metadata -Zfixed-x18 --crate-type rlib --crate-name core $(rustc --print sysroot)/lib/rustlib/src/rust/library/core/src/lib.rs

echo '#![allow(internal_features)]
' | RUSTC_BOOTSTRAP=1 rustdoc --edition=2021 --target=aarch64-unknown-none-softfloat --sysroot=/dev/null -Zfixed-x18 --extern core=libcore.rmeta -

will fail with:

error: mixing `-Zfixed-x18` will cause an ABI mismatch in crate `rust_out`
  |
  = help: the `-Zfixed-x18` flag modifies the ABI so Rust crates compiled with different values of this flag cannot be used together safely
  = note: unset `-Zfixed-x18` in this crate is incompatible with `-Zfixed-x18=` in dependency `core`
  = help: set `-Zfixed-x18=` in this crate or unset `-Zfixed-x18` in `core`
  = help: if you are sure this will not cause problems, you may use `-Cunsafe-allow-abi-mismatch=fixed-x18` to silence this error

Thus save the targets modifiers in Options to then pass it to the session options, so that eventually the diff can be performed as expected in report_incompatible_target_modifiers().

Cc: @azhogin
Fixes: #144521

rustbot · 2025-07-27T00:05:41Z

r? @GuillaumeGomez

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rustbot · 2025-07-27T02:31:24Z

This PR modifies run-make tests.

cc @jieyouxu

ojeda · 2025-07-27T02:33:51Z

Added a test and removed the @user.

`rustdoc` was filling a `target_modifiers` variable, but it was not using the result. In turn, that means that trying to use a dependency that set a target modifier fails. For instance, running: ```sh RUSTC_BOOTSTRAP=1 rustc --edition=2024 --target=aarch64-unknown-none-softfloat --sysroot=/dev/null --emit=metadata -Zfixed-x18 --crate-type rlib --crate-name core $(rustc --print sysroot)/lib/rustlib/src/rust/library/core/src/lib.rs echo '#![allow(internal_features)] ' | RUSTC_BOOTSTRAP=1 rustdoc --edition=2021 --target=aarch64-unknown-none-softfloat --sysroot=/dev/null -Zfixed-x18 --extern core=libcore.rmeta - ``` will fail with: ```text error: mixing `-Zfixed-x18` will cause an ABI mismatch in crate `rust_out` | = help: the `-Zfixed-x18` flag modifies the ABI so Rust crates compiled with different values of this flag cannot be used together safely = note: unset `-Zfixed-x18` in this crate is incompatible with `-Zfixed-x18=` in dependency `core` = help: set `-Zfixed-x18=` in this crate or unset `-Zfixed-x18` in `core` = help: if you are sure this will not cause problems, you may use `-Cunsafe-allow-abi-mismatch=fixed-x18` to silence this error ``` Thus save the targets modifiers in `Options` to then pass it to the session options, so that eventually the diff can be performed as expected in `report_incompatible_target_modifiers()`. Fixes: rust-lang#144521 Signed-off-by: Miguel Ojeda <[email protected]>

Starting with Rust 1.88.0 (released 2025-06-26), `rustdoc` complains about a target modifier mismatch in configurations where `-Zfixed-x18` is passed: error: mixing `-Zfixed-x18` will cause an ABI mismatch in crate `rust_out` | = help: the `-Zfixed-x18` flag modifies the ABI so Rust crates compiled with different values of this flag cannot be used together safely = note: unset `-Zfixed-x18` in this crate is incompatible with `-Zfixed-x18=` in dependency `core` = help: set `-Zfixed-x18=` in this crate or unset `-Zfixed-x18` in `core` = help: if you are sure this will not cause problems, you may use `-Cunsafe-allow-abi-mismatch=fixed-x18` to silence this error The reason is that `rustdoc` was not passing the target modifiers when configuring the session options, and thus it would report a mismatch that did not exist as soon as a target modifier is used in a dependency. We did not notice it in the kernel until now because `-Zfixed-x18` has been a target modifier only since 1.88.0 (and it is the only one we use so far). The issue has been reported upstream [1] and a fix has been submitted [2], including a test similar to the kernel case. Meanwhile, conditionally pass `-Cunsafe-allow-abi-mismatch=fixed-x18` to workaround the issue on our side. Reported-by: Konrad Dybcio <[email protected]> Closes: https://lore.kernel.org/rust-for-linux/[email protected]/ Link: rust-lang/rust#144521 [1] Link: rust-lang/rust#144523 [2] Signed-off-by: Miguel Ojeda <[email protected]>

GuillaumeGomez · 2025-07-27T09:29:19Z

Nice, thanks!

@bors r+ rollup

bors · 2025-07-27T09:29:22Z

📌 Commit 558796b has been approved by GuillaumeGomez

It is now in the queue for this repository.

Starting with Rust 1.88.0 (released 2025-06-26), `rustdoc` complains about a target modifier mismatch in configurations where `-Zfixed-x18` is passed: error: mixing `-Zfixed-x18` will cause an ABI mismatch in crate `rust_out` | = help: the `-Zfixed-x18` flag modifies the ABI so Rust crates compiled with different values of this flag cannot be used together safely = note: unset `-Zfixed-x18` in this crate is incompatible with `-Zfixed-x18=` in dependency `core` = help: set `-Zfixed-x18=` in this crate or unset `-Zfixed-x18` in `core` = help: if you are sure this will not cause problems, you may use `-Cunsafe-allow-abi-mismatch=fixed-x18` to silence this error The reason is that `rustdoc` was not passing the target modifiers when configuring the session options, and thus it would report a mismatch that did not exist as soon as a target modifier is used in a dependency. We did not notice it in the kernel until now because `-Zfixed-x18` has been a target modifier only since 1.88.0 (and it is the only one we use so far). The issue has been reported upstream [1] and a fix has been submitted [2], including a test similar to the kernel case. Meanwhile, conditionally pass `-Cunsafe-allow-abi-mismatch=fixed-x18` to workaround the issue on our side. Reported-by: Konrad Dybcio <[email protected]> Closes: https://lore.kernel.org/rust-for-linux/[email protected]/ Link: rust-lang/rust#144521 [1] Link: rust-lang/rust#144523 [2] Signed-off-by: Miguel Ojeda <[email protected]>

…GuillaumeGomez rustdoc: save target modifiers `rustdoc` was filling a `target_modifiers` variable, but it was not using the result. In turn, that means that trying to use a dependency that set a target modifier fails. For instance, running: ```sh RUSTC_BOOTSTRAP=1 rustc --edition=2024 --target=aarch64-unknown-none-softfloat --sysroot=/dev/null --emit=metadata -Zfixed-x18 --crate-type rlib --crate-name core $(rustc --print sysroot)/lib/rustlib/src/rust/library/core/src/lib.rs echo '#![allow(internal_features)] ' | RUSTC_BOOTSTRAP=1 rustdoc --edition=2021 --target=aarch64-unknown-none-softfloat --sysroot=/dev/null -Zfixed-x18 --extern core=libcore.rmeta - ``` will fail with: ```text error: mixing `-Zfixed-x18` will cause an ABI mismatch in crate `rust_out` | = help: the `-Zfixed-x18` flag modifies the ABI so Rust crates compiled with different values of this flag cannot be used together safely = note: unset `-Zfixed-x18` in this crate is incompatible with `-Zfixed-x18=` in dependency `core` = help: set `-Zfixed-x18=` in this crate or unset `-Zfixed-x18` in `core` = help: if you are sure this will not cause problems, you may use `-Cunsafe-allow-abi-mismatch=fixed-x18` to silence this error ``` Thus save the targets modifiers in `Options` to then pass it to the session options, so that eventually the diff can be performed as expected in `report_incompatible_target_modifiers()`. Cc: `@azhogin` Fixes: rust-lang#144521

Rollup of 7 pull requests Successful merges: - #143289 (Remove `[T]::array_chunks(_mut)`) - #143607 (Port the proc macro attributes to the new attribute parsing infrastructure) - #144471 (Remove `compiler-builtins-{no-asm,mangled-names}`) - #144495 (bump cargo_metadata) - #144523 (rustdoc: save target modifiers) - #144534 (check_static_item: explain should_check_for_sync choices) - #144535 (miri: for ABI mismatch errors, say which argument is the problem) Failed merges: - #144536 (miri subtree update) r? `@ghost` `@rustbot` modify labels: rollup

Rollup of 6 pull requests Successful merges: - #143607 (Port the proc macro attributes to the new attribute parsing infrastructure) - #144471 (Remove `compiler-builtins-{no-asm,mangled-names}`) - #144495 (bump cargo_metadata) - #144523 (rustdoc: save target modifiers) - #144534 (check_static_item: explain should_check_for_sync choices) - #144535 (miri: for ABI mismatch errors, say which argument is the problem) Failed merges: - #144536 (miri subtree update) r? `@ghost` `@rustbot` modify labels: rollup

Rollup merge of #144523 - ojeda:rustdoc-target-modifiers, r=GuillaumeGomez rustdoc: save target modifiers `rustdoc` was filling a `target_modifiers` variable, but it was not using the result. In turn, that means that trying to use a dependency that set a target modifier fails. For instance, running: ```sh RUSTC_BOOTSTRAP=1 rustc --edition=2024 --target=aarch64-unknown-none-softfloat --sysroot=/dev/null --emit=metadata -Zfixed-x18 --crate-type rlib --crate-name core $(rustc --print sysroot)/lib/rustlib/src/rust/library/core/src/lib.rs echo '#![allow(internal_features)] ' | RUSTC_BOOTSTRAP=1 rustdoc --edition=2021 --target=aarch64-unknown-none-softfloat --sysroot=/dev/null -Zfixed-x18 --extern core=libcore.rmeta - ``` will fail with: ```text error: mixing `-Zfixed-x18` will cause an ABI mismatch in crate `rust_out` | = help: the `-Zfixed-x18` flag modifies the ABI so Rust crates compiled with different values of this flag cannot be used together safely = note: unset `-Zfixed-x18` in this crate is incompatible with `-Zfixed-x18=` in dependency `core` = help: set `-Zfixed-x18=` in this crate or unset `-Zfixed-x18` in `core` = help: if you are sure this will not cause problems, you may use `-Cunsafe-allow-abi-mismatch=fixed-x18` to silence this error ``` Thus save the targets modifiers in `Options` to then pass it to the session options, so that eventually the diff can be performed as expected in `report_incompatible_target_modifiers()`. Cc: ``@azhogin`` Fixes: #144521

ojeda · 2025-07-28T06:18:26Z

Thanks for the quick review!

Rollup of 6 pull requests Successful merges: - rust-lang/rust#143607 (Port the proc macro attributes to the new attribute parsing infrastructure) - rust-lang/rust#144471 (Remove `compiler-builtins-{no-asm,mangled-names}`) - rust-lang/rust#144495 (bump cargo_metadata) - rust-lang/rust#144523 (rustdoc: save target modifiers) - rust-lang/rust#144534 (check_static_item: explain should_check_for_sync choices) - rust-lang/rust#144535 (miri: for ABI mismatch errors, say which argument is the problem) Failed merges: - rust-lang/rust#144536 (miri subtree update) r? `@ghost` `@rustbot` modify labels: rollup

…iaskrgr Rollup of 6 pull requests Successful merges: - rust-lang#143607 (Port the proc macro attributes to the new attribute parsing infrastructure) - rust-lang#144471 (Remove `compiler-builtins-{no-asm,mangled-names}`) - rust-lang#144495 (bump cargo_metadata) - rust-lang#144523 (rustdoc: save target modifiers) - rust-lang#144534 (check_static_item: explain should_check_for_sync choices) - rust-lang#144535 (miri: for ABI mismatch errors, say which argument is the problem) Failed merges: - rust-lang#144536 (miri subtree update) r? `@ghost` `@rustbot` modify labels: rollup

Rollup of 6 pull requests Successful merges: - rust-lang/rust#143607 (Port the proc macro attributes to the new attribute parsing infrastructure) - rust-lang/rust#144471 (Remove `compiler-builtins-{no-asm,mangled-names}`) - rust-lang/rust#144495 (bump cargo_metadata) - rust-lang/rust#144523 (rustdoc: save target modifiers) - rust-lang/rust#144534 (check_static_item: explain should_check_for_sync choices) - rust-lang/rust#144535 (miri: for ABI mismatch errors, say which argument is the problem) Failed merges: - rust-lang/rust#144536 (miri subtree update) r? `@ghost` `@rustbot` modify labels: rollup

Starting with Rust 1.88.0 (released 2025-06-26), `rustdoc` complains about a target modifier mismatch in configurations where `-Zfixed-x18` is passed: error: mixing `-Zfixed-x18` will cause an ABI mismatch in crate `rust_out` | = help: the `-Zfixed-x18` flag modifies the ABI so Rust crates compiled with different values of this flag cannot be used together safely = note: unset `-Zfixed-x18` in this crate is incompatible with `-Zfixed-x18=` in dependency `core` = help: set `-Zfixed-x18=` in this crate or unset `-Zfixed-x18` in `core` = help: if you are sure this will not cause problems, you may use `-Cunsafe-allow-abi-mismatch=fixed-x18` to silence this error The reason is that `rustdoc` was not passing the target modifiers when configuring the session options, and thus it would report a mismatch that did not exist as soon as a target modifier is used in a dependency. We did not notice it in the kernel until now because `-Zfixed-x18` has been a target modifier only since 1.88.0 (and it is the only one we use so far). The issue has been reported upstream [1] and a fix has been submitted [2], including a test similar to the kernel case. [ This is now fixed upstream (thanks Guillaume for the quick review), so it will be fixed in Rust 1.90.0 (expected 2025-09-18). - Miguel ] Meanwhile, conditionally pass `-Cunsafe-allow-abi-mismatch=fixed-x18` to workaround the issue on our side. Cc: [email protected] # Needed in 6.12.y and later (Rust is pinned in older LTSs). Reported-by: Konrad Dybcio <[email protected]> Closes: https://lore.kernel.org/rust-for-linux/[email protected]/ Link: rust-lang/rust#144521 [1] Link: rust-lang/rust#144523 [2] Reviewed-by: Alice Ryhl <[email protected]> Link: https://lore.kernel.org/r/[email protected] Signed-off-by: Miguel Ojeda <[email protected]>

commit abbf9a4 upstream. Starting with Rust 1.88.0 (released 2025-06-26), `rustdoc` complains about a target modifier mismatch in configurations where `-Zfixed-x18` is passed: error: mixing `-Zfixed-x18` will cause an ABI mismatch in crate `rust_out` | = help: the `-Zfixed-x18` flag modifies the ABI so Rust crates compiled with different values of this flag cannot be used together safely = note: unset `-Zfixed-x18` in this crate is incompatible with `-Zfixed-x18=` in dependency `core` = help: set `-Zfixed-x18=` in this crate or unset `-Zfixed-x18` in `core` = help: if you are sure this will not cause problems, you may use `-Cunsafe-allow-abi-mismatch=fixed-x18` to silence this error The reason is that `rustdoc` was not passing the target modifiers when configuring the session options, and thus it would report a mismatch that did not exist as soon as a target modifier is used in a dependency. We did not notice it in the kernel until now because `-Zfixed-x18` has been a target modifier only since 1.88.0 (and it is the only one we use so far). The issue has been reported upstream [1] and a fix has been submitted [2], including a test similar to the kernel case. [ This is now fixed upstream (thanks Guillaume for the quick review), so it will be fixed in Rust 1.90.0 (expected 2025-09-18). - Miguel ] Meanwhile, conditionally pass `-Cunsafe-allow-abi-mismatch=fixed-x18` to workaround the issue on our side. Cc: [email protected] # Needed in 6.12.y and later (Rust is pinned in older LTSs). Reported-by: Konrad Dybcio <[email protected]> Closes: https://lore.kernel.org/rust-for-linux/[email protected]/ Link: rust-lang/rust#144521 [1] Link: rust-lang/rust#144523 [2] Reviewed-by: Alice Ryhl <[email protected]> Link: https://lore.kernel.org/r/[email protected] Signed-off-by: Miguel Ojeda <[email protected]> Signed-off-by: Greg Kroah-Hartman <[email protected]>

Starting with Rust 1.88.0 (released 2025-06-26), `rustdoc` complains about a target modifier mismatch in configurations where `-Zfixed-x18` is passed: error: mixing `-Zfixed-x18` will cause an ABI mismatch in crate `rust_out` | = help: the `-Zfixed-x18` flag modifies the ABI so Rust crates compiled with different values of this flag cannot be used together safely = note: unset `-Zfixed-x18` in this crate is incompatible with `-Zfixed-x18=` in dependency `core` = help: set `-Zfixed-x18=` in this crate or unset `-Zfixed-x18` in `core` = help: if you are sure this will not cause problems, you may use `-Cunsafe-allow-abi-mismatch=fixed-x18` to silence this error The reason is that `rustdoc` was not passing the target modifiers when configuring the session options, and thus it would report a mismatch that did not exist as soon as a target modifier is used in a dependency. We did not notice it in the kernel until now because `-Zfixed-x18` has been a target modifier only since 1.88.0 (and it is the only one we use so far). The issue has been reported upstream [1] and a fix has been submitted [2], including a test similar to the kernel case. [ This is now fixed upstream (thanks Guillaume for the quick review), so it will be fixed in Rust 1.90.0 (expected 2025-09-18). - Miguel ] Meanwhile, conditionally pass `-Cunsafe-allow-abi-mismatch=fixed-x18` to workaround the issue on our side. Cc: [email protected] # Needed in 6.12.y and later (Rust is pinned in older LTSs). Reported-by: Konrad Dybcio <[email protected]> Closes: https://lore.kernel.org/rust-for-linux/[email protected]/ Link: rust-lang/rust#144521 [1] Link: rust-lang/rust#144523 [2] Reviewed-by: Alice Ryhl <[email protected]> Link: https://lore.kernel.org/r/[email protected] Signed-off-by: Miguel Ojeda <[email protected]>

rustbot assigned GuillaumeGomez Jul 27, 2025

rustbot added S-waiting-on-review Status: Awaiting review from the assignee but also interested parties. T-rustdoc Relevant to the rustdoc team, which will review and decide on the PR/issue. labels Jul 27, 2025

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rustdoc wanted features & bugfixes Rust-for-Linux/linux#350

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rustdoc cannot use dependencies with target modifiers #144521

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ojeda force-pushed the rustdoc-target-modifiers branch from 3bcb62d to 7eff864 Compare July 27, 2025 02:31

rustbot added the A-run-make Area: port run-make Makefiles to rmake.rs label Jul 27, 2025

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ojeda force-pushed the rustdoc-target-modifiers branch from 7eff864 to 558796b Compare July 27, 2025 03:22

GuillaumeGomez approved these changes Jul 27, 2025

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bors added S-waiting-on-bors Status: Waiting on bors to run and complete tests. Bors will change the label on completion. and removed S-waiting-on-review Status: Awaiting review from the assignee but also interested parties. labels Jul 27, 2025

jhpratt mentioned this pull request Jul 27, 2025

Rollup of 7 pull requests #144546

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matthiaskrgr mentioned this pull request Jul 27, 2025

Rollup of 6 pull requests #144556

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bors merged commit d776c5a into rust-lang:master Jul 28, 2025
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