For chains of async functions where suspensions can be statically
proven to never be required, this pass removes all suspensions and
turns the functions into synchronous functions.
For example, this function does not actually require any suspensions,
once the correct executor is acquired upon initial entry:
```
func fib(_ n: Int) async -> Int {
if n <= 1 { return n }
return await fib(n-1) + fib(n-2)
}
```
So we can turn the above into this for better performance:
```
func fib() async -> Int {
return fib_sync()
}
func fib_sync(_ n: Int) -> Int {
if n <= 1 { return n }
return fib(n-1) + fib(n-2)
}
```
while rewriting callers of `fib` to use the `sync` entry-point
when we can prove that it will be invoked on a compatible executor.
This pass is currently experimental and under development. Thus, it
is disabled by default and you must use
`-enable-experimental-async-demotion` to try it.
The original `--ld-path` option hasn't been included in a released version yet, so it's ok to break.
The vast majority of other options on Swift Driver already use a single dash.
To enable MCCAS, the following driver options have been added
-cas-backend: Enable MCCAS backend in swift, the option
-cache-compile-job must also be used.
-cas-backend-mode=native: Set the CAS Backend mode to emit an object
file after materializing it from the CAS.
-cas-backend-mode=casid: Emit a file with the CASID for the CAS that was
created.
-cas-backend-mode=verify: Verify that the object file created is
identical to the object file materialized from the CAS.
-cas-emit-casid-file: Emit a .casid file next to the object file when
CAS Backend is enabled.
This enables one to use varying prefixes when checking diagnostics with the
DiagnosticVerifier. So for instance, I can make a test work both with and
without send-non-sendable enabled by adding additional prefixes. As an example:
```swift
// RUN: %target-swift-frontend ... -verify-additional-prefix no-sns-
// RUN: %target-swift-frontend ... -verify-additional-prefix sns-
let x = ... // expected-error {{This is always checked no matter what prefixes I added}}
let y = ... // expected-no-sns-error {{This is only checked if send non sendable is disabled}}
let z = ... // expected-sns-error {{This is only checked if send non sendable is enabled}}
let w = ... // expected-no-sns-error {{This is checked for a specific error when sns is disabled...}}
// expected-sns-error @-1 {{and for a different error when sns is enabled}}
```
rdar://114643840
This option is designed to be used in conjunction with
`-experimental-lazy-typecheck` and `-experimental-skip-all-function-bodies`
when emitting a resilient module. The emitted binary module should contain only
the decls needed by clients and should contain roughly the same contents as it
would if the corresponding swiftinterface were emitted instead and then built.
This functionality is a work in progress. Some parts of the AST may still get
typechecked unnecessarily. Additionally, serialization does not trigger the
appropriate typechecking requests for some ASTs and then fails due to missing
types.
Resolves rdar://114230586
Macro implementations can come from various locations associated with
different search paths. Add a frontend flag `-Rmacro-loading` to emit
a remark when each macro implementation module is resolved, providing
the kind of macro (shared library, executable, shared library loaded
via the plugin server) and appropriate paths. This allows one to tell
from the build load which macros are used.
Addresses rdar://110780311.
This action is currently just an alias of the `-resolve-imports` action.
However, it's named to more clearly reflect the purpose which is to do the
minimal typechecking needed in order to emit the requested outputs. This mode
is intended to improve performance when emitting `.swiftinterface` and `.tbd`
files.
When `-warn-on-potentially-unavailable-enum-case` was introduced, the build
system was required to invoke `swift-frontend` at artificially low deployment
targets when emitting `.swiftinterface` files for legacy architectures. Because
the deployment target was low, some availability diagnostics needed to be
de-fanged in order to allow module interface emission to succeed. Today, the
build system is able to use the correct deployment target when emitting module
interfaces and the `-warn-on-potentially-unavailable-enum-case` is superfluous,
so deprecate it.
Resolves rdar://114092047
Frontend options should only be printed under `swift-module-flags-ignored:`
temporarily to prevent condfails for older development compilers that are still
in use (as a rule of thumb, swiftinterfaces should be compatible with compilers
that are up to 6 months old). None of the frontend flags that are currently
categorized as "ignorable" need to be ignorable anymore.
Instead of the code querying the compiler's built-in Clang instance, refactor the
dependency scanner to explicitly keep track of module output path. It is still
set according to '-module-cache-path' as it has been prior to this change, but
now the scanner can use a different module cache for scanning PCMs, as specified
with '-clang-scanner-module-cache-path', without affecting module output path.
Resolves rdar://113222853
Clang dependency scanning produces scanner PCMs which we may want to live in a
different filesystem location than the main build module cache.
Resolves rdar://113222853
Ensure that we process `-libc` in `swift-symbolgraph-extract` and
`swift-api-extract`. This option is used by Windows to determine the C
ABI to use and thus impacts the ABI exposed by the ClangImporter to the
Swift interface. This partially enables the use of
`swift package dump-symbol-graph` on Windows.
Allow `-typecheck-module-from-interface` using explicit module instead
of building implicit module.
This setups swift-frontend to accept explicit module build arguments and
loading explicit module during verifying. SwiftDriver needs to setup
correct arguments including the output path for swift module to fully
enable explicit module interface check.
