Avoid using env::temp when linking a binary
This keeps all build artefacts (even temporary ones) within the build directory.
Fixesrust-lang/rust#139963
Don't leak sysroot crates through dependencies
Previously if a dependency of the current crate depended on a sysroot crate, then `extern crate` would in the current crate would pick the first loaded version of said sysroot crate even in case of an ambiguity. This is surprising and brittle. For `-Ldependency=` we already blocked this since rust-lang/rust#110229, but the fix didn't account for sysroot crates.
Should fix https://github.com/rust-lang/rust/issues/147966
Remove -Zoom=panic
There are major questions remaining about the reentrancy that this allows. It doesn't have any users on github outside of a single project that uses it in a panic=abort project to show backtraces. It can still be emulated through `#[alloc_error_handler]` or `set_alloc_error_hook` depending on if you use the standard library or not. And finally it makes it harder to do various improvements to the allocator shim.
With this PR the sole remaining symbol in the allocator shim that is not effectively emulating weak symbols is the symbol that prevents skipping the allocator shim on stable even when it would otherwise be empty because libstd + `#[global_allocator]` is used.
Closes https://github.com/rust-lang/rust/issues/43596
Fixes https://github.com/rust-lang/rust/issues/126683
There are major questions remaining about the reentrancy that this
allows. It doesn't have any users on github outside of a single project
that uses it in a panic=abort project to show backtraces. It
can still be emulated through #[alloc_error_handler] or
set_alloc_error_hook depending on if you use the standard library or
not. And finally it makes it harder to do various improvements to the
allocator shim.
Port the `#![windows_subsystem]` attribute to the new attribute system
Part of rust-lang/rust#131229.
I think it's worth running the Windows test suite before merging that (I don't have the rights for this).
It is never used anywhere anymore now that existing_matches doesn't use
it anymore. And there is no good reason for any other code to use it in
the future either.
Add LLVM realtime sanitizer
This is a new attempt at adding the [LLVM real-time sanitizer](https://clang.llvm.org/docs/RealtimeSanitizer.html) to rust.
Previously this was attempted in https://github.com/rust-lang/rfcs/pull/3766.
Since then the `sanitize` attribute was introduced in https://github.com/rust-lang/rust/pull/142681 and it is a lot more flexible than the old `no_santize` attribute. This allows adding real-time sanitizer without the need for a new attribute, like it was proposed in the RFC. Because i only add a new value to a existing command line flag and to a attribute i don't think an MCP is necessary.
Currently real-time santizer is usable in rust code with the [rtsan-standalone](https://crates.io/crates/rtsan-standalone) crate. This downloads or builds the sanitizer runtime and then links it into the rust binary.
The first commit adds support for more detailed sanitizer information.
The second commit then actually adds real-time sanitizer.
The third adds a warning against using real-time sanitizer with async functions, cloures and blocks because it doesn't behave as expected when used with async functions. I am not sure if this is actually wanted, so i kept it in a seperate commit.
The fourth commit adds the documentation for real-time sanitizer.
Offload device
LLVM's offload functionality usually expects an extra dyn_ptr argument. We could avoid it,b ut likely gonna need it very soon in one of the follow-up PRs (e.g. to request shared memory). So we might as well already add it.
This PR adds a %dyn_ptr ptr to GPUKernel ABI functions, if the offload feature is enabled.
WIP
r? ```@ghost```
Add default sanitizers to TargetOptions
Some sanitizers are part of a system's ABI, like the shadow call stack on Aarch64 and RISC-V Fuchsia. Typically ABI options have other spellings, but LLVM has, for historical reasons, marked this as a sanitizer instead of an alternate ABI option. As a result, Fuchsia targets may not be compiled against the correct ABI unless this option is set. This hasn't caused correctness problems, since the backend reserves the SCS register, and thus preserves its value. But this is an issue for unwinding, as the SCS will not be an array of PCs describing the call complete call chain, and will have gaps from callers that don't use the correct ABI.
In the long term, I'd like to see all the sanitizer configs that all frontends copy from clang moved into llvm's libFrontend, and exposed so that frontend consumers can use a small set of simple APIs to use sanitizers in a consistent way across the LLVM ecosystem, but that work is not yet ready today.
Some sanitizers are part of a system's ABI, like the shadow call stack
on Aarch64 and RISC-V Fuchsia. Typically ABI options have other
spellings, but LLVM has, for historical reasons, marked this as a
sanitizer instead of an alternate ABI option. As a result, Fuchsia
targets may not be compiled against the correct ABI unless this option
is set. This hasn't caused correctness problems, since the backend
reserves the SCS register, and thus preserves its value. But this is an
issue for unwinding, as the SCS will not be an array of PCs describing
the call complete call chain, and will have gaps from callers that don't
use the correct ABI.
In the long term, I'd like to see all the sanitizer configs that all
frontends copy from clang moved into llvm's libFrontend, and exposed so
that frontend consumers can use a small set of simple APIs to use
sanitizers in a consistent way across the LLVM ecosystem, but that work
is not yet ready today.
Currently it is possible to avoid linking the allocator shim when
__rust_no_alloc_shim_is_unstable_v2 is defined when linking rlibs
directly as some build systems need. However this requires liballoc to
be compiled with --cfg no_global_oom_handling, which places huge
restrictions on what functions you can call and makes it impossible to
use libstd. Or alternatively you have to define
__rust_alloc_error_handler and (when using libstd)
__rust_alloc_error_handler_should_panic
using #[rustc_std_internal_symbol]. With this commit you can either use
libstd and define __rust_alloc_error_handler_should_panic or not use
libstd and use #[alloc_error_handler] instead. Both options are still
unstable though.
Eventually the alloc_error_handler may either be removed entirely
(though the PR for that has been stale for years now) or we may start
using weak symbols for it instead. For the latter case this commit is a
prerequisite anyway.
[win] Use find-msvc-tools instead of cc to find the linker and rc on Windows
`find-msvc-tools` was factored out from `cc` to allow updating the use in `rustc_codegen_ssa` (finding the linker when running the Rust compiler) and `rustc_windows_rc` (finding the Windows Resource Compiler when running the Rust compiler) to be separate from the use in `rustc_llvm` (building LLVM as part of building the Rust compiler).
Add panic=immediate-abort
MCP: https://github.com/rust-lang/compiler-team/issues/909
This adds a new panic strategy, `-Cpanic=immediate-abort`. This panic strategy essentially just codifies use of `-Zbuild-std-features=panic_immediate_abort`. This PR is intended to just set up infrastructure, and while it will change how the compiler is invoked for users of the feature, there should be no other impacts.
In many parts of the compiler, `PanicStrategy::ImmediateAbort` behaves just like `PanicStrategy::Abort`, because actually most parts of the compiler just mean to ask "can this unwind?" so I've added a helper function so we can say `sess.panic_strategy().unwinds()`.
The panic and unwind strategies have some level of compatibility, which mostly means that we can pre-compile the sysroot with unwinding panics then the sysroot can be linked with aborting panics later. The immediate-abort strategy is all-or-nothing, enforced by `compiler/rustc_metadata/src/dependency_format.rs` and this is tested for in `tests/ui/panic-runtime/`. We could _technically_ be more compatible with the other panic strategies, but immediately-aborting panics primarily exist for users who want to eliminate all the code size responsible for the panic runtime. I'm open to other use cases if people want to present them, but not right now. This PR is already large.
`-Cpanic=immediate-abort` sets both `cfg(panic = "immediate-abort")` _and_ `cfg(panic = "abort")`. bjorn3 pointed out that people may be checking for the abort cfg to ask if panics will unwind, and also the sysroot feature this is replacing used to require `-Cpanic=abort` so this seems like a good back-compat step. At least for the moment. Unclear if this is a good idea indefinitely. I can imagine this being confusing.
The changes to the standard library attributes are purely mechanical. Apart from that, I removed an `unsafe` we haven't needed for a while since the `abort` intrinsic became safe, and I've added a helpful diagnostic for people trying to use the old feature.
To test that `-Cpanic=immediate-abort` conflicts with other panic strategies, I've beefed up the core-stubs infrastructure a bit. There is now a separate attribute to set flags on it.
I've added a test that this produces the desired codegen, called `tests/run-make-cargo/panic-immediate-abort-codegen/` and also a separate run-make-cargo test that checks that we can build a binary.
This commit updates the target specification of wasm targets to set the
`limit_rdylib_exports` value to `true` like it is on other native
platforms. This was originally not implemented long ago as `wasm-ld`
didn't have options for symbol exports, but since then it's grown a
`--export` flag and such to control this. A custom case is needed in the
linker implementation to handle wasm targets as `wasm-ld` doesn't
support linker scripts used on other targets, but other than that the
implementation is straightforward.
The goal of this commit is enable building dynamic libraries on
`wasm32-wasip2` which don't export every single symbol in the Rust
standard library. Currently, without otherwise control over symbol
visibility, all symbols end up being exported which generates
excessively large binaries because `--gc-sections` ends up doing nothing
as it's all exported anyway.
Jonathan Brouwer