Link MSVC default lib in core
## The Problem
On Windows MSVC, Rust invokes the linker directly. This means only the objects and libraries Rust explicitly passes to the linker are used. In short, this is equivalent to passing `-nodefaultlibs`, `-nostartfiles`, etc for gnu compilers.
To compensate for this [the libc crate links to the necessary libraries](a0f5b4b213/src/windows/mod.rs (L258-L261)). The libc crate is then linked from std, thus when you use std you get the defaults back.or integrate with C/C++.
However, this has a few problems:
- For `no_std`, users are left to manually pass the default lib to the linker
- Whereas `std` has the opposite problem, using [`/nodefaultlib`](https://learn.microsoft.com/en-us/cpp/build/reference/nodefaultlib-ignore-libraries?view=msvc-170) doesn't work as expected because Rust treats them as normal libs. This is a particular problem when you want to use e.g. the debug CRT libraries in their place or integrate with C/C++..
## The solution
This PR fixes this in two ways:
- moves linking the default lib into `core`
- passes the lib to the linker using [`/defaultlib`](https://learn.microsoft.com/en-us/cpp/build/reference/defaultlib-specify-default-library?view=msvc-170). This allows users to override it in the normal way (i.e. with [`/nodefaultlib`](https://learn.microsoft.com/en-us/cpp/build/reference/nodefaultlib-ignore-libraries?view=msvc-170)).
This is more or less equivalent to what the MSVC C compiler does. You can see what this looks like in my second commit, which I'll reproduce here for convenience:
```rust
// In library/core
#[cfg(all(windows, target_env = "msvc"))]
#[link(
name = "/defaultlib:msvcrt",
modifiers = "+verbatim",
cfg(not(target_feature = "crt-static"))
)]
#[link(name = "/defaultlib:libcmt", modifiers = "+verbatim", cfg(target_feature = "crt-static"))]
extern "C" {}
```
## Alternatives
- Add the above to `unwind` and `std` but not `core`
- The status quo
- Some other kind of compiler magic maybe
This bares some discussion so I've t-libs nominated it.
previously we would explicitly look for exit code 101 and call it a crash,
however in case of stack overflows for example, exit code could differ due to the
process being killed by a signal which is not easy to detect on none-unix.
So now we reject everything that exits with 0 (no error) or 1 (compiler failed to compile code)
and "accept" everyhing else as an internal compiler error.
Rollup of 8 pull requests
Successful merges:
- #123651 (Thread local updates for idiomatic examples)
- #123699 (run-make-support: tidy up support library)
- #123779 (OpenBSD fix long socket addresses)
- #123875 (Doc: replace x with y for hexa-decimal fmt)
- #123879 (Add missing `unsafe` to some internal `std` functions)
- #123889 (reduce tidy overheads in run-make checks)
- #123898 (Generic associated consts: Check regions earlier when comparing impl with trait item def)
- #123902 (compiletest: Update rustfix to 0.8.1)
r? `@ghost`
`@rustbot` modify labels: rollup
compiletest: Update rustfix to 0.8.1
This updates the version of rustfix used in compiletest to be closer to what cargo is using. This is to help ensure `cargo fix` and compiletest are aligned. There are some unpublished changes to `rustfix`, which will update in a future PR when those are published.
Will plan to update ui_test in the near future to avoid the duplicate.
reduce tidy overheads in run-make checks
This change makes tidy to handle run-make checks with a single iteration, avoiding the need for multiple iterations and copying.
Add missing `unsafe` to some internal `std` functions
Adds `unsafe` to a few internal functions that have safety requirements but were previously not marked as `unsafe`. Specifically:
- `std::sys::pal::unix:🧵:min_stack_size` needs to be `unsafe` as `__pthread_get_minstack` might dereference the passed pointer. All callers currently pass a valid initialised `libc::pthread_attr_t`.
- `std:🧵:Thread::new` (and `new_inner`) need to be `unsafe` as it requires the passed thread name to be valid UTF-8, otherwise `Thread::name` will trigger undefined behaviour. I've taken the opportunity to split out the unnamed thread case into a separate `new_unnamed` function to make the safety requirement clearer. All callers meet the safety requirement now that #123505 has been merged.
Doc: replace x with y for hexa-decimal fmt
I found it a bit unintuitive to know which is variable and which is the format string in `format!("{x:x}")`, so I switched it to `y`.
OpenBSD fix long socket addresses
Original diff from ``@notgull`` in #118349, small changes from me.
on OpenBSD, getsockname(2) returns the actual size of the socket address, and not the len of the content. Figure out the length for ourselves. see https://marc.info/?l=openbsd-bugs&m=170105481926736&w=2Fixes#116523
run-make-support: tidy up support library
- Make `handle_failed_output` take `&Command` instead of having the caller keep doing `format!("{:#?}", s)`.
- Introduce a helper macro for implementing common command wrappers, such as `arg`, `args`, `run`, `run_fail`.
- Use the helper macro on existing command wrappers and remove manual copy-pasta'd implementations.
Thread local updates for idiomatic examples
Update thread local examples to make more idiomatic use of `Cell` for `Copy` types, `RefCell` for non-`Copy` types.
Also shrink the size of `unsafe` blocks, add `SAFETY` comments, and fix `clippy::redundant_closure_for_method_calls`.
Get rid of `USIZE_MARKER` in formatting infrastructure
An alternative to #123780.
The `USIZE_MARKER` function used to differentiate between placeholder and count arguments is never called anyway, so we can just replace the function-pointer-comparison hack with an `enum` and an `unreachable_unchecked`, hopefully without causing a regression.
CC `@RalfJung`
bootstrap: move all of rustc's flags to `rustc_cargo`
This ensures that `RUSTFLAGS` will be consistent between all modes of
building the compiler, so they won't trigger a rebuild by cargo. This
kind of fix was started in #119414 just for LTO flags, but it's
applicable to all kinds of flags that might be configured.
Add add/sub methods that only panic with debug assertions to rustc
This mitigates the perf impact of enabling overflow checks on rustc. The change to use overflow checks will be done in a later PR.
For rust-lang/compiler-team#724, based on data gathered in #119440.
Rollup of 7 pull requests
Successful merges:
- #123530 (Enable building tier2 target riscv32im-unknown-none-elf)
- #123642 (do not allow using local llvm while using rustc from ci)
- #123716 (Update documentation of Path::to_path_buf and Path::ancestors)
- #123876 (Update backtrace submodule)
- #123888 (Replace a `DefiningOpaqueTypes::No` with `Yes` by asserting that one side of the comparison is a type variable.)
- #123890 (removed (mostly) unused code)
- #123891 (Miri subtree update)
r? `@ghost`
`@rustbot` modify labels: rollup
Add a helper macro for adding common methods to command wrappers. Common
methods include helpers that delegate to `Command` and running methods.
- `arg` and `args` (delegates to `Command`)
- `env`, `env_remove` and `env_clear` (delegates to `Command`)
- `output`, `run` and `run_fail`
This helps to avoid needing to copy-pasta / reimplement these common
methods on a new command wrapper, which hopefully reduces the friction
for run-make test writers wanting to introduce new command wrappers.
Replace a `DefiningOpaqueTypes::No` with `Yes` by asserting that one side of the comparison is a type variable.
Thus there will never be an opaque type involved in a way that constrains its hidden type, as the other side of the comparison is always a generator witness type
r? ``@compiler-errors``
