Use the unwind crate to implement libunwind interfaces.
#37
Conversation
Factoring these out into separate files appears to be insufficient to force them to all be linked in, replacing libc, so pull them all into a single module.
The `unwind` crate appears to work well for this purpose, even on panics with RUST_BACKTRACE=full. This uses the `fde-phdr-dl` backend, which uses `dl_iterate_phdr`, so implement `dl_iterate_phdr`. Fixes #27.
Unwind doesn't support 32-bit x86 yet, so drop it for now.
It's used by `init_have_lse_atomics` in libgcc/compiler-rt.
This has a better chance of allowing a user to open the file reliably.
| pub(crate) const AT_HWCAP2: c_ulong = 26; | ||
| pub(crate) const AT_EXECFN: c_ulong = 31; | ||
| pub(crate) const AT_SYSINFO: c_ulong = 32; | ||
| pub(crate) const AT_SYSINFO_EHDR: c_ulong = 33; |
There was a problem hiding this comment.
Shouldn't these be in linux-raw-sys?
There was a problem hiding this comment.
In this case, no, because c-scape is implementing the userspace libc ABI, and glibc and musl don't guarantee that their ABIs match Linux's ABI. They both have their own copies of these constants rather than just re-exporting the definitions from Linux's headers.
|
Would fde-phdr-aux work? |
|
Yeah, mustang could use either fde-phdr-aux or fde-phdr-dl. Do you prefer we use fde-phdr-aux? |
|
I don't have a preference. I added fde-phdr-aux thinking it might be useful for you, but implementing dl_iterate_phdr would work too. |
|
BTW I have renamed the repo |
|
Awesome, thanks! And thanks so much for developing unwinding, it works great in everything I've tried with it, on both x86-64 and aarch64, and fills a major gap for mustang overall! 32-bit x86 support would be convenient, as it would let us remove the stub unwind API implementation, but it's not a blocker for anything. |
|
x86 support is completed. You may still want to keep your stubs though since there are no AArch32/PowerPC/MIPS support in |
|
I've now updated to the version with x86 support, and enabled a bunch more tests, including several which include panics and This PR is now just waiting on a |
|
These patches are pulled in by #7. I've also temporarily disabled unwinding on aarch64 and riscv64 to avoid needing to patch in a git dependency on gimli for now. |
The
unwindcrate appears to work well for this purpose, even on panics withRUST_BACKTRACE=full.
This uses the
fde-phdr-dlbackend, which usesdl_iterate_phdr, so implementdl_iterate_phdr.Fixes #27.