On windows (PECOFF), the `static let` properties produced by `DebugDescriptionMacro`
are not constants, and as a result the `@_section` macro cannot be applied. The error
message is:
> global variable must be a compile-time constant to use `@_section` attribute
Until this issue is addressed, DebugDescriptionMacro is disabled for windows targets.
The data emitted by `DebugDescriptionMacro` is constant. For that reason, it was placed
in `__DATA_CONST`. However, this causes a problem with the linker, which emits an error
if the `__DATA_CONST` segment is _not_ marked `SG_READ_ONLY`.
After discussion, it was pointed out that if the constant data has no fixups, then it
can and should be in the the `__TEXT` segment. The `__DATA_CONST` segment is for data
that is essentially constant but contains dyld fixups.
Fixes the way `DebugDescriptionMacro` produces a regex type name.
The problem was use of backslash escapes that weren't sufficiently escaped. They needed
to be double escaped. To avoid this trap, the regexes now use `[.]` to match a dot,
instead of the more conventional `\.` syntax.
Some data types cannot modify their `description` or `debugDescription` properties, as
modification to those properties could result in breakage to their users. To support
these conditions, `DebugDescriptionMacro` should support and prioritize an independent
property (one that that is not being reused).
This change adds support for `_debugDescription`. The macro will now prioritize the
description properties in this order:
1. `_debugDescription`
2. `debugDescription`
3. `debugDescription`
rdar://120498021
Implementation of the DebugDescription macro pitched on the forums:
https://forums.swift.org/t/pitch-debug-description-macro/67711. In this initial commit,
the macro is named `_DebugDescription` to indicate it's internal use at this time,
pending Swift Evolution.
rdar://115180949
Use FetchContent to include swift-syntax directly in swift. This can be
thought of as an `add_subdirectory` for a directory outside the root.
The default build directory will be `_deps/swiftsyntax-subbuild/`, though
the modules and shared libraries will be built in `lib/swift/host` by
passing down `SWIFT_HOST_LIBRARIES_DEST_DIR` to avoid copying them as we
were doing previously.
* Move `add_pure_swift_host_library()` from lib/CMakeLists.txt to
AddPureSwift.cmake so that code outside `lib` can use it
* Add `add_pure_swift_host_tool()` function to make a pure Swift
host executable target (for future usages)
* Specify depending `SwiftSyntax` modules explicitly because not all
Swift libraries uses all SwiftSyntax libraries
