Rollup of 9 pull requests

Successful merges:

 - #128425 (Make `missing_fragment_specifier` an unconditional error)
 - #135927 (retpoline and retpoline-external-thunk flags (target modifiers) to enable retpoline-related target features)
 - #140770 (add `extern "custom"` functions)
 - #142176 (tests: Split dont-shuffle-bswaps along opt-levels and arches)
 - #142248 (Add supported asm types for LoongArch32)
 - #142267 (assert more in release in `rustc_ast_lowering`)
 - #142274 (Update the stdarch submodule)
 - #142276 (Update dependencies in `library/Cargo.lock`)
 - #142308 (Upgrade `object`, `addr2line`, and `unwinding` in the standard library)

Failed merges:

 - #140920 (Extract some shared code from codegen backend target feature handling)

r? `@ghost`
`@rustbot` modify labels: rollup

try-job: aarch64-apple
try-job: x86_64-msvc-1
try-job: x86_64-gnu
try-job: dist-i586-gnu-i586-i686-musl
try-job: test-various

Rollup of 9 pull requests

Successful merges:

 - #128425 (Make `missing_fragment_specifier` an unconditional error)
 - #135927 (retpoline and retpoline-external-thunk flags (target modifiers) to enable retpoline-related target features)
 - #140770 (add `extern "custom"` functions)
 - #142176 (tests: Split dont-shuffle-bswaps along opt-levels and arches)
 - #142248 (Add supported asm types for LoongArch32)
 - #142267 (assert more in release in `rustc_ast_lowering`)
 - #142274 (Update the stdarch submodule)
 - #142276 (Update dependencies in `library/Cargo.lock`)
 - #142308 (Upgrade `object`, `addr2line`, and `unwinding` in the standard library)

Failed merges:

 - #140920 (Extract some shared code from codegen backend target feature handling)

r? `@ghost`
`@rustbot` modify labels: rollup

try-job: aarch64-apple
try-job: x86_64-msvc-1
try-job: x86_64-gnu
try-job: dist-i586-gnu-i586-i686-musl
try-job: test-various

Rollup merge of #140770 - folkertdev:custom-abi, r=tgross35

add `extern "custom"` functions

tracking issue: #140829
previous discussion: #140566

In short, an `extern "custom"` function is a function with a custom ABI, that rust does not know about. Therefore, such functions can only be defined with `#[unsafe(naked)]` and `naked_asm!`, or via an `extern "C" { /* ... */ }` block. These functions cannot be called using normal rust syntax: calling them can only be done from inline assembly.

The motivation is low-level scenarios where a custom calling convention is used. Currently, we often pick `extern "C"`, but that is a lie because the function does not actually respect the C calling convention.

At the moment `"custom"` seems to be the name with the most support. That name is not final, but we need to pick something to actually implement this.

r? `@traviscross`
cc `@tgross35`

try-job: x86_64-apple-2

…iaskrgr

Rollup of 9 pull requests

Successful merges:

 - rust-lang#128425 (Make `missing_fragment_specifier` an unconditional error)
 - rust-lang#135927 (retpoline and retpoline-external-thunk flags (target modifiers) to enable retpoline-related target features)
 - rust-lang#140770 (add `extern "custom"` functions)
 - rust-lang#142176 (tests: Split dont-shuffle-bswaps along opt-levels and arches)
 - rust-lang#142248 (Add supported asm types for LoongArch32)
 - rust-lang#142267 (assert more in release in `rustc_ast_lowering`)
 - rust-lang#142274 (Update the stdarch submodule)
 - rust-lang#142276 (Update dependencies in `library/Cargo.lock`)
 - rust-lang#142308 (Upgrade `object`, `addr2line`, and `unwinding` in the standard library)

Failed merges:

 - rust-lang#140920 (Extract some shared code from codegen backend target feature handling)

r? `@ghost`
`@rustbot` modify labels: rollup

try-job: aarch64-apple
try-job: x86_64-msvc-1
try-job: x86_64-gnu
try-job: dist-i586-gnu-i586-i686-musl
try-job: test-various

add `extern "custom"` functions

tracking issue: rust-lang#140829
previous discussion: rust-lang#140566

In short, an `extern "custom"` function is a function with a custom ABI, that rust does not know about. Therefore, such functions can only be defined with `#[unsafe(naked)]` and `naked_asm!`, or via an `extern "C" { /* ... */ }` block. These functions cannot be called using normal rust syntax: calling them can only be done from inline assembly.

The motivation is low-level scenarios where a custom calling convention is used. Currently, we often pick `extern "C"`, but that is a lie because the function does not actually respect the C calling convention.

At the moment `"custom"` seems to be the name with the most support. That name is not final, but we need to pick something to actually implement this.

r? `@traviscross`
cc `@tgross35`

try-job: x86_64-apple-2