Since llvm/llvm-project 159143, llvm no longer weak links the __cpp_exception tag into
each object that uses it. They are now defined in compiler-rt. Rust doesn't seem to
get them from compiler-rt so llvm decides they need to be imported. This adds them to
libunwind.
unwind/wasm: fix compile error by wrapping wasm_throw in unsafe block
This fix rust-std compile error on wasm32-unknown-unknown with panic=unwind because of `#![deny(unsafe_op_in_unsafe_fn)]`
Discovered while porting libstd to hexagon-unknown-qurt: the
unwinder data size refers to the count of pointers in _Unwind_Exception but
when I put the value "35" intiially for hexagon linux, I incorrectly
considered the size of the exception context hexagon_thread_state_t
data structure.
Correct the value for hexagon linux and expand it to cover all
hexagon architecture instead.
Fixes library linking issues where libgcc_s was incorrectly being linked
instead of the appropriate LLVM runtime libraries for Hexagon targets.
* Set llvm-libunwind as default for all hexagon targets in bootstrap
* Exclude hexagon from automatic libgcc_s linking in unwind
* Enable libunwind.a copying for hexagon targets
* Remove manual library linking from hexagon target specification
rustc assumes that regular `extern "Rust"` functions unwind only if the
`unwind` panic runtime is linked. `throw` was annotated as such, but
unwound unconditionally. This could cause UB when a crate built with `-C
panic=abort` called `throw` from `core` built with `-C panic=unwind`,
since no terminator was added to handle the panic arising from calling an
allegedly non-unwinding `extern "Rust"` function.
rustc was taught to recognize this condition since
https://github.com/rust-lang/rust/pull/144225 and prevented such
linkage, but this caused regressions in
https://github.com/rust-lang/rust/issues/148246, since this meant that
Emscripten projects could not be built with `-C panic=abort` without
recompiling std.
The most straightforward solution would be to move `throw` into the
`panic_unwind` crate, so that it's only compiled if the panic runtime is
guaranteed to be `unwind`, but this is messy due to our architecture.
Instead, move it into `unwind::wasm`, which is only compiled for
bare-metal targets that default to `panic = "abort"`, rendering the
issue moot.
Migrate the standard library from using the external `cfg_if` crate to
using the now-built-in `cfg_select` macro.
This does not yet eliminate the dependency from
`library/std/Cargo.toml`, because while the standard library itself no
longer uses `cfg_if`, it also incorporates the `backtrace` crate, which
does.
Migration assisted by the following vim command (after selecting the
full `cfg_if!` invocation):
```
'<,'>s/\(cfg_if::\)\?cfg_if/cfg_select/ | '<,'>s/^\( *\)} else {/\1}\r\1_ => {/c | '<,'>s/^\( *\)} else if #\[cfg(\(.*\))\] /\1}\r\1\2 => /e | '<,'>s/if #\[cfg(\(.*\))\] {/\1 => {/e
```
This is imperfect, but substantially accelerated the process. This
prompts for confirmation on the `} else {` since that can also appear
inside one of the arms. This also requires manual intervention to handle
any multi-line conditions.
The three panic-related library crates need to have access to `core`,
and `compiler-builtins` needs to be in the crate graph. Rather than
specifying both dependencies, switch these crates to use
`rustc-std-workspace-core` which already does this.
This means there is now a single place that the `compiler-builtins`
dependency needs to get configured, for everything other than `alloc`
and `std`.
Many of `std`'s dependency have a dependency on the crates.io
`compiler-builtins` when used with the feature
`rustc-std-workspace-core`. Use a Cargo patch to select the in-tree
version instead.
`compiler-builtins` is also added as a dependency of
`rustc-std-workspace-core` so these crates can remove their crates.io
dependency in the future.
With a recent change to the compiler, all instances of `#[naked]` must
now be wrapped in `#[unsafe(naked)]`. The `unwinding` crate, which is
used on Xous for doing unwinding in constrained environments, needed to
be updated to handle this change.
Bump the `unwinding` dependency to 0.2.6, which performs this wrapping.
Signed-off-by: Sean Cross <sean@xobs.io>
Make `_Unwind_Action` a type alias, not enum
It's bitflags in practice, so an enum is unsound, as an enum must only have the described values. The x86_64 psABI declares it as a `typedef int _Unwind_Action`, which seems reasonable. I made a newtype first but that was more annoying than just a typedef. We don't really use this value for much other than a short check.
I ran `x check library --target aarch64-unknown-linux-gnu,x86_64-pc-windows-gnu,x86_64-fortanix-unknown-sgx,x86_64-unknown-haiku,x86_64-unknown-fuchsi
a,x86_64-unknown-freebsd,x86_64-unknown-dragonfly,x86_64-unknown-netbsd,x86_64-unknown-openbsd,x86_64-unknown-redox,riscv64-linux-android,armv7-unknown-freebsd` (and some more but they failed to build for other reasons :D)
fixes#138558
r? workingjubilee have fun
It's bitflags in practice, so an enum is unsound, as an enum must only
have the described values. The x86_64 psABI declares it as a `typedef
int _Unwind_Action`, which seems reasonable. I made a newtype first but
that was more annoying than just a typedef. We don't really use this
value for much other than a short check.
Use `std::mem::{size_of, size_of_val, align_of, align_of_val}` from the
prelude instead of importing or qualifying them.
These functions were added to all preludes in Rust 1.80.
Add support for wasm exception handling to Emscripten target
This is a draft because we need some additional setting for the Emscripten target to select between the old exception handling and the new exception handling. I don't know how to add a setting like that, would appreciate advice from Rust folks. We could maybe choose to use the new exception handling if `Ctarget-feature=+exception-handling` is passed? I tried this but I get errors from llvm so I'm not doing it right.
With #80608 the `unwinding` crate no longer builds. The upstream crate
has been updated to build by manually adding directives to the naked_asm
stream.
Bump the dependency in Rust to get this newer version. This fixes the
build for Xous, and closes#134403.
Signed-off-by: Sean Cross <sean@xobs.io>
Various fixes for Xous
This patchset includes several fixes for Xous that have crept in over the last few months:
* The `adjust_process()` syscall was incorrect
* Warnings have started appearing in `alloc` -- adopt the same approach as wasm, until wasm figures out a workaround
* Dead code warnings have appeared in the networking code. Add `allow(dead_code)` as these structs are used as IPC values
* Add support for `args` and `env`, which have been useful for running tests
* Update `unwinding` to `0.2.3` which fixes the recent regression due to changes in `asm!()` code
The recent changes to naked `asm!()` macros made this unbuildable
on Xous. The upstream package maintainer released 0.2.3 to fix support
on newer nightly toolchains.
Update the dependency to 0.2.3, which is the oldest version that works
with the current nightly compiler.
This closes#131602 and fixes the build on xous.
Signed-off-by: Sean Cross <sean@xobs.io>
Since the stabilization in #127679 has reached stage0, 1.82-beta, we can
start using `&raw` freely, and even the soft-deprecated `ptr::addr_of!`
and `ptr::addr_of_mut!` can stop allowing the unstable feature.
I intentionally did not change any documentation or tests, but the rest
of those macro uses are all now using `&raw const` or `&raw mut` in the
standard library.
In https://github.com/rust-lang/rust/pull/124748, I mistakenly conflated
"not SjLj" to mean "ARM EHABI", which isn't true, watchOS armv7k
(specifically only that architecture) uses a third unwinding method
called "DWARF CFI".
Folkert de Vries