The ELF specification says that if a section's type is set to `SHT_NULL`,
_none_ of the other fields are valid, so we shouldn't even be trying to
read the section name.
(We won't crash, because of how all of this code works, but we might
read an incorrect name.)
rdar://154837649
Musl's `clone()` wrapper returns `EINVAL` if you try to use `CLONE_THREAD`,
which seems a bit wrong (certainly it is in this particular application,
since we *really* don't care whether the thread is a valid C library
thread at this point).
Also properly support ELF images that are built with a base address other
than zero (this typically isn't an issue for dynamically linked programs,
as they will be relocated at runtime anyway, but for statically linked
binaries it's very common to set the base address to a non-zero value).
rdar://154282813
When fixing the previous problem, I should have realised that this
would cascade; the `@_specialize` annotations refer to the cached
versions of the types, and those are now turned off except on macOS
and Linux because they rely on the uncached versions, which are only
available on macOS and Linux.
rdar://144023438
To do this we also need to fix AddSwiftStdlib because if you set the
`INSTALL_WITH_SHARED` flag, the CMake scripts don't make a target
with the `-static` suffix, but AddSwiftStdlib also assumes that it
should dad `-static` to any module dependencies when building a
static library.
Added some explanatory text to the Compact Backtrace Format
documentation, and also to the `CMakeLists.txt` for the runtime.
Tweaked the conversions for `Backtrace.Address` to truncate, which
should result in reasonable behaviour for negative fixed-width
integers.
Use a constant for the ASCII values for `/` and `\` in the Compact
Image Format encoder/decoder.
Make the TSD key for `ElfImageCache` non-optional, and call
`fatalError()` if we don't get one.
rdar://124913332
It's useful to capture the platform and platform version with the image map.
Also, display both the platform and architecture information when generating
a crash log.
rdar://124913332
If we ended up with a `/` at the beginning of a string segment, we
were erroneously not adding to the expansion dictionary when we
should have been.
rdar://124913332
Also removed a spurious `print()` that got left in by accident,
and disabled the `CodableBacktrace.swift` test on Linux since we
need Foundation and we don't have it there.
rdar://124913332
Remove a `-disable-implicit-backtracing-module-import` that was added
in `Runtimes/Core/CMakeLists.txt`, and also remove the reference to
`swiftCxxStdlib` from `RuntimeModule` as that causes the build to fail
when attempting to build the static version of `swift-backtrace` on
Linux.
rdar://124913332
We already try using `CFStringGetCStringPtr` to see if we can get ASCII;
we should also try `CFStringGetCharactersPtr` as the native encoding of
`CFNSString` is very often UTF-16. While we're at it, try asking explicitly
for UTF-8 as well. That won't work for `CFNSString` because AFAIK it's
currently never encoded that way, but it might work if something hands us
a Swift-backed string or if some future implementation of `CFString`
happens to support UTF-8 encoded data.
rdar://124913332
We want to be able to efficiently serialise lists of images, and to do so
it makes most sense to create a separate `ImageMap` type. This also provides
a useful place to put methods to e.g. find an image by address or by build
ID.
rdar://124913332
Move the backtracing code into a new Runtime module. This means renaming
the Swift Runtime's CMake target because otherwise there will be a name
clash.
rdar://124913332
