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
