[Backtracing][Linux] Add Linux support to swift-backtrace. #66337
Conversation
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
This was referenced Jun 5, 2023
|
@swift-ci Please smoke test |
al45tair
force-pushed
the
eng/PR-110262673
branch
from
76e4076
to
4cb5441
Compare
|
@swift-ci Please smoke test |
|
If you're wondering where the tests are, I left them until the last PR (#66338) so everything was enabled and they'd actually work. |
MaxDesiatov
reviewed
Jun 6, 2023
MaxDesiatov
reviewed
Jun 6, 2023
MaxDesiatov
reviewed
Jun 6, 2023
The Swift backtracer's frame pointer unwinder cannot work on Linux without this change, because the compiler omits the frame pointer from the function in libSwift_Backtracing that actually captures the stack. rdar://110260855
Using `SwiftShims` is undesirable - it creates all kinds of build issues, and means shipping the `_SwiftBacktracing.h` header in the SDK, which is not necessary. While we're doing this, add the necessary definitions for reading ELF and DWARF information. rdar://110261712
Use the new module structure rather the old SwiftShims header. This is much cleaner and lets us include operating system headers to get the relevant definitions where possible. Add code to support ELF and DWARF, including decompression using zlib, zstd and liblzma if those turn out to be required and available. rdar://110261712
This is for compatibility, so that I can split up the PRs. We'll remove it in the next PR. rdar://110261712
al45tair
force-pushed
the
eng/PR-110262673
branch
from
4cb5441
to
746d626
Compare
|
@swift-ci Please smoke test |
There's a chance that pipes might perform a partial read; we should handle that case. rdar://110261712
al45tair
force-pushed
the
eng/PR-110262673
branch
from
746d626
to
6f294f9
Compare
|
@swift-ci Please smoke test |
The `status` argument to the `_swift_backtrace_demangle()` function isn't especially useful, won't match behaviour on Windows, and we actually don't use it in the Swift code that calls this SPI. Remove it. rdar://110261712
`__cxa_demangle()` is a rather unusual API; one of its "features" is that the pointer you pass in must either be `nullptr`, in which case it will call `malloc()` itself, _or_ it has to be a pointer to a block of memory allocated with `malloc()`, because `__cxa_demangle()` may `realloc()` it for you. This seems to me to be something of a non-obvious footgun, so we never pass the caller's pointer through to `__cxa_demangle()`, which lets them decide how they want to allocate space. rdar://110261712
al45tair
force-pushed
the
eng/PR-110262673
branch
from
6f294f9
to
6ffd1ef
Compare
|
@swift-ci Please smoke test |
…ule. There's a separate declaration here because we can't include the `Backtrace.h` header from inside `modules/Runtime/Runtime.h`. rdar://110261712
The `_Backtracing` module has a number of private implementation only imports that aren't used outside of the module and that don't require any additional libraries (hence they aren't relevant to the outside world). `verify_all_overlays.py` needs to know about these when it does its test, because it loadas the module as the main module, which results in implementation only imports being required instead of ignored. rdar://110261712
We need a Linux specific `Target` implementation, and a couple of minor tweaks to make things build everywhere. rdar://110262673
This reverts commit 0d7c45d.
We don't need these here. They were a leftover from previous code. rdar://110262673
al45tair
force-pushed
the
eng/PR-110262673
branch
from
6ffd1ef
to
df8e698
Compare
|
@swift-ci Please smoke test |
MaxDesiatov
approved these changes
Jun 7, 2023
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
Add this suggestion to a batch that can be applied as a single commit.
This suggestion is invalid because no changes were made to the code.
Suggestions cannot be applied while the pull request is closed.
Suggestions cannot be applied while viewing a subset of changes.
Only one suggestion per line can be applied in a batch.
Add this suggestion to a batch that can be applied as a single commit.
Applying suggestions on deleted lines is not supported.
You must change the existing code in this line in order to create a valid suggestion.
Outdated suggestions cannot be applied.
This suggestion has been applied or marked resolved.
Suggestions cannot be applied from pending reviews.
Suggestions cannot be applied on multi-line comments.
Suggestions cannot be applied while the pull request is queued to merge.
Suggestion cannot be applied right now. Please check back later.
We need a Linux specific
Targetimplementation, and a couple of minor tweaks to make things build everywhere.rdar://110262673