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Rollup merge of #140194 - jieyouxu:minicore-force-unwind-tables, r=bjorn3 

minicore: Have `//@ add-core-stubs` also imply `-Cforce-unwind-tables=yes`

To preserve CFI directives in assembly tests, as `//@ add-core-stubs` already imply `-C panic=abort`.

This is a blocker for https://github.com/rust-lang/rust/pull/140037#issuecomment-2816665358.

cc ```@RalfJung```
r? ```@bjorn3```
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Matthias Krüger 2025-04-24 11:40:42 +02:00 committed by GitHub
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ui/codegen/assembly test suites. It provides `core` stubs for tests that need to
build for cross-compiled targets but do not need/want to run.
A test can use [`minicore`] by specifying the `//@ add-core-stubs` directive.
Then, mark the test with `#![feature(no_core)]` + `#![no_std]` + `#![no_core]`.
Due to Edition 2015 extern prelude rules, you will probably need to declare
`minicore` as an extern crate.
Due to the `no_std` + `no_core` nature of these tests, `//@ add-core-stubs`
implies and requires that the test will be built with `-C panic=abort`.
Unwinding panics are not supported.
If you find a `core` item to be missing from the [`minicore`] stub, consider
adding it to the test auxiliary if it's likely to be used or is already needed
by more than one test.
<div class="warning">
Please note that [`minicore`] is only intended for `core` items, and explicitly
**not** `std` or `alloc` items because `core` items are applicable to a wider
range of tests.
</div>
A test can use [`minicore`] by specifying the `//@ add-core-stubs` directive.
Then, mark the test with `#![feature(no_core)]` + `#![no_std]` + `#![no_core]`.
Due to Edition 2015 extern prelude rules, you will probably need to declare
`minicore` as an extern crate.
## Implied compiler flags
Due to the `no_std` + `no_core` nature of these tests, `//@ add-core-stubs`
implies and requires that the test will be built with `-C panic=abort`.
**Unwinding panics are not supported.**
Tests will also be built with `-C force-unwind-tables=yes` to preserve CFI
directives in assembly tests.
TL;DR: `//@ add-core-stubs` implies two compiler flags:
1. `-C panic=abort`
2. `-C force-unwind-tables=yes`
## Adding more `core` stubs
If you find a `core` item to be missing from the [`minicore`] stub, consider
adding it to the test auxiliary if it's likely to be used or is already needed
by more than one test.
## Example codegen test that uses `minicore`
```rust,no_run