...instead of sometimes hardcoding them and sometimes using Strings.h.
The exceptions are the libraries that sit below Frontend; these can
continue using strings.
...but don't hook it up to anything yet.
This is the very very start of the module stability / textual
interfaces feature described at
https://forums.swift.org/t/plan-for-module-stability/14551/
For now I've just made it a frontend option (not a driver option),
which is good enough for testing.
Introduces the -name-bind frontend action that is intended as an intermediary between the parse-only actions and a full typechecking pass. In this phase, module imports will be validated and resolved, making it possible to emit full make-style dependencies files among other things.
Note that all information available to a parse-only pass is available to name binding, but because it does not continue-on to typecheck input files, full semantic information is not.
Parse-only invocations do not support the proper creation of dependency files or reference dependency files because they have not yet run name binding. Ban these invocations by diagnostic and add a new diagnostic specifically for reference dependencies.
This flag is based on Clang's -fdebug-prefix-map, which lets the user remap absolute paths in debug info. This is necessary for reproducible builds and allows debugging to work on a different machine than the one that built the code when paths to the source may be different.
The bundling of the form of a request (e.g., the storage that makes up a request)
with the function that evaluates the request value requires us to perform
ad hoc indirection to address the AST —> Sema layering violation. For
example, ClassDecl::getSuperclass() calls through the LazyResolver (when
available) to form the appropriate request. This means that we cannot
use the the request-evaluator’s cache when LazyResolver is null, forcing
all cached state into the AST.
Provide the evaluator with a zone-based registration system, where each
request “zone” (e.g., the type checker’s requests) registers
callbacks to evaluate each kind of request within that zone. The
evaluator indirects through this table of function pointers, allowing
the request classes themselves to be available at a lower level (AST)
than the functions that perform the computation when the value isn’t
in the cache (e.g., Sema).
We are not taking advantage of the indirection yet; that’ll come in a
follow-up commit.
Introduce a command-line option to visualize the complete set of output
request dependencies evaluated by a particular compile action. This is
exposing existing visualization facilities to the (-frontend) command line.
We sometimes see expression type checking times increase dramatically
when this is enabled, and having a way to disable will make it
possible to easily do measurements to determine the cost/benefit of
having this enabled.
As a debugging aid, introduce a new frontend flag `-debug-cycles` that
will emit a debug dump whenever the request-evaluator encounters a cyclic
dependency, while otherwise allowing compilation to continue.
This work-around is no longer needed now that the full fix landed in
https://github.com/apple/swift/pull/16615. The argument is left with a warning
to help with migration between compilers with the work-around and compilers with
the full fix (see also rdar://problem/40502379).
Fixes rdar://problem/40476573.
