Preliminary caching support for macro:
* Inserting the plugin into the CASFS
* Lookup plugin via physical file system
For future better support, we should teach dependency scanner to resolve
macros and return the resolved plugins to swift-frontend.
rdar://121873571
Improve swift dependency scanner by validating and selecting dependency
module into scanner. This provides benefits that:
* Build system does not need to schedule interface compilation task if
the candidate module is picked, it can just use the candidate module
directly.
* There is no need for forwarding module in the explicit module build.
Since the build system is coordinating the build, there is no need for
the forwarding module in the module cache to avoid duplicated work,
* This also correctly supports all the module loading modes in the
dependency scanner.
This is achieved by only adding validate and up-to-date binary module as
the candidate module for swift interface module dependency. This allows
caching build to construct the correct dependency in the CAS. If there
is a candidate module for the interface module, dependency scanner will
return a binary module dependency in the dependency graph.
The legacy behavior is mostly preserved with a hidden frontend flag
`-no-scanner-module-validation`, while the scanner output is mostly
interchangeable with new scanner behavior with `prefer-interface` module
loading mode except the candidate module will not be returned.
rdar://123711823
Support `-vfsoverlay` swift option for explicit module build (including
caching build). Previously, if the interface file is discovered from a
location that is remapped by overlay, module cannot be built correctly.
Make sure the overlay options are passed down to all interface
compilaiton command.
For caching build, need to make sure the overlay itself is part of the CAS
file system so the downstream compilation can discover that.
rdar://123655183
Otherwise they may have module dependencies of their own which will not be detected by the scanner and included in the list of explicit inputs for compilation.
Guard 'resetCache' and 'resetDiagnostics' as critical sections using 'DependencyScanningToolStateLock'. Otherwise there's a chance that one thread in the scanner is doing a reset on the diagnostic consumer, while some other thread is adding this diagnostic consumer to another scan instance which may also be populating said consumer at the time. Similarly, for resetting 'ScanningService' though it is much more unlikely to be reset while in-use by other scanning actions.
SE-0364 was implemented to discourage "retroactive" conformances that might
conflict with conformances that could be introduced by other modules in the
future. These diagnostics should not apply to conformances that involve types
and protocols imported from the underlying clang module of a Swift module since
the two modules are assumed to be developed in tandem by the same owners,
despite technically being separate modules from the perspective of the
compiler.
The diagnostics implemented in https://github.com/apple/swift/pull/36068 were
designed to take underlying clang modules into account. However, the
implementation assumed that `ModuleDecl::getUnderlyingModuleIfOverlay()` would
behave as expected when called on the Swift module being compiled.
Unfortunately, it would always return `nullptr` and thus conformances involving
the underlying clang module are being diagnosed unexpectedly.
The fix is to make `ModuleDecl::getUnderlyingModuleIfOverlay()` behave as
expected when it is made up of `SourceFile`s.
Resolves rdar://121478556
Fix a typo in the name of legacy layout file name that causes the legacy
layouts are not ingested into the CASFS for cached compilation.
rdar://119622429
* Remove 'OptimizeArgs = true' on the ClangDependencyScanningService init
With the new API this is no longer a boolean and the new default value of 'ScanningOptimizations::Default' matches the behavior we had prior to this change.
This matches the current behavior in `ImportResolution`. The change refactors an existing utility function to do this check from `UnboundImport` to a common utility used now also in the scanner.
The code, previously, only properly handled such dependencies being a distinct category for Swift source and Swift textual dependency infos. Swift binary module dependencies must handle this similarly and this change adds the missing support for them. Recent refactor of the scanner also means that now Swift binary dependencies with Swift overlay dependencies may crash the scanner, and this change resolves this as well.
Resolves rdar://117088840
Allow DependencyScanner to canonicalize path using a prefix map. When
option `-scanner-prefix-map` option is used, dependency scanner will
remap all the input paths in following:
* all the paths in the CAS file system or clang include tree
* all the paths related to input on the command-line returned by scanner
This allows all the input paths to be canonicalized so cache key can be
computed reguardless of the exact on disk path.
The sourceFile field is not remapped so build system can track the exact
file as on the local file system.
'ModuleDependencyScanner' maintains a Thread Pool along with a pool of workers
which are capable of executing a filesystem lookup of a named module dependency.
When resolving imports of a given Swift module, each import's resolution
operation can be issued asunchronously.
From being a scattered collection of 'static' methods in ScanDependencies.cpp
and member methods of ASTContext. This makes 'ScanDependencies.cpp' much easier
to read, and abstracts the actual scanning logic away to a place with common
state which will make it easier to reason about in the future.
dependencies
It is valuable for clients to be able to distinguish which dependencies of a
Swift module originated from 'import' statements, and which ones are implicit
dependency Swift overlays of imported Clang modules.
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
Unlike `swift-frontend -scan-dependencies` option, when dependency
scanner is used as a library by swift driver, the SwiftScanningService
is shared for multiple driver invocations. It can't keep states (like
common file dependencies) that can change from one invocation to
another.
Instead, the clang/SDK file dependencies are computed from each driver
invocations to avoid out-of-date information when scanning service is
reused.
The test case for a shared Service will be added to swift-driver repo
since there is no tool to test it within swift compiler.
Reformatting everything now that we have `llvm` namespaces. I've
separated this from the main commit to help manage merge-conflicts and
for making it a bit easier to read the mega-patch.
This is phase-1 of switching from llvm::Optional to std::optional in the
next rebranch. llvm::Optional was removed from upstream LLVM, so we need
to migrate off rather soon. On Darwin, std::optional, and llvm::Optional
have the same layout, so we don't need to be as concerned about ABI
beyond the name mangling. `llvm::Optional` is only returned from one
function in
```
getStandardTypeSubst(StringRef TypeName,
bool allowConcurrencyManglings);
```
It's the return value, so it should not impact the mangling of the
function, and the layout is the same as `std::optional`, so it should be
mostly okay. This function doesn't appear to have users, and the ABI was
already broken 2 years ago for concurrency and no one seemed to notice
so this should be "okay".
I'm doing the migration incrementally so that folks working on main can
cherry-pick back to the release/5.9 branch. Once 5.9 is done and locked
away, then we can go through and finish the replacement. Since `None`
and `Optional` show up in contexts where they are not `llvm::None` and
`llvm::Optional`, I'm preparing the work now by going through and
removing the namespace unwrapping and making the `llvm` namespace
explicit. This should make it fairly mechanical to go through and
replace llvm::Optional with std::optional, and llvm::None with
std::nullopt. It's also a change that can be brought onto the
release/5.9 with minimal impact. This should be an NFC change.
Rename `-enable-cas` to `-compile-cache-job` to align with clang option
names and promote that to a new driver only flag.
Few other additions to driver flag for caching behaviors:
* `-compile-cache-remarks`: now cache hit/miss remarks are guarded behind
this flag
* `-compile-cache-skip`: skip replaying from the cache. Useful as a
debugging tool to do the compilation using CAS inputs even the output
is a hit from the cache.
Teach swift dependency scanner to use CAS to capture the full dependencies for a build and construct build commands with immutable inputs from CAS.
This allows swift compilation caching using CAS.
Instead of being a part of 'directDependencies' on a module dependency info, make them a separate array of dependency IDs for Swift Source and Textual modules.
This will allow clients to still distinguish direct module dependencies imported from a given module, versus dependencies added because direct/transitive Clang module dependencies have Swift overlays.
This change does *not* remove overlay dependencies from 'directDependencies' yet, just adds them as a separate field on the module details info. A followup change will remove overlay and bridging header dependencies from 'directDependencies' once the clients have had a chance to adopt to this change.
For a `@Testable` import in program source, if a Swift interface dependency is discovered, and has an adjacent binary `.swiftmodule`, open up the module, and pull in its optional dependencies. If an optional dependency cannot be resolved on the filesystem, fail silently without raising a diagnostic.
Instead, treat them like any other module that is specific to the scanning context hash of the scan it originates from.
Otherwise we may actually have simultaneous scans happening for the same source module but with different context hashes, and the current scheme leads to collisions.
Using mutual exclusion, ensuring that multiple threads executing dependency scans do not encounter data races on shared mutable state.
There are two layers with shared state where we need to be careful:
- `DependencyScanningTool`, as the main entity that scanning clients interact with. This tool instantiates compiler instances for individual scans, computing a scanning invocation hash. It needs to remember those instances for future use, and when creating instances it needs to reset LLVM argument processor's global state, meaning all uses of argument processing must be in a critical section.
- `SwiftDependencyScanningService`, as the main cache where dependency scanning results are stored. Each individual scan instantiates a `ModuleDependenciesCache`, which uses the scanning service as the underlying storage. The services' storage is segmented to storing dependencies discovered in a scan with a given context hash, which means two different scanning invocations running at the same time will be accessing different locations in its storage, thus not requiring synchronization. But the service still has some shared state that must be protected, such as the collection of discovered source modules, and the map used to query context-hash-specific underlying cache storage.
If a scanner instance is used for multiple scans, the `SwiftDependencyScanningService` will have collected prior scans' main source modules' dependency info.
Suppose the scanner first scans a source module `A` and records its dependencies. If a successive scan of some source module `B` finds that it depends on `A`, it would get a cache hit on the source module from a prior scan and re-use dependency information. This change no longer allows such re-use of the prior source module scan dependencies. Said prior scan may have had an entirely different context and therefore different set of dependencies on `A` than may be visible otherwise. Instead, all scanning actions must rely on such modules being re-discovered on the filesystem.
This changes the scanner's behavior to "resolve" a discovered module's dependencies to a set of Module IDs: module name + module kind (swift textual, swift binary, clang, etc.).
The 'ModuleDependencyInfo' objects that are stored in the dependency scanner's cache now carry a set of kind-qualified ModuleIDs for their dependencies, in addition to unqualified imported module names of their dependencies.
Previously, the scanner's internal state would cache a module dependnecy as having its own set of dependencies which were stored as names of imported modules. This led to a design where any time we needed to process the dependency downstream from its discovery (e.g. cycle detection, graph construction), we had to query the ASTContext to resolve this dependency's imports, which shouldn't be necessary. Now, upon discovery, we "resolve" a discovered dependency by executing a lookup for each of its imported module names (this operation happens regardless of this patch) and store a fully-resolved set of dependencies in the dependency module info.
Moreover, looking up a given module dependency by name (via `ASTContext`'s `getModuleDependencies`) would result in iterating over the scanner's module "loaders" and querying each for the module name. The corresponding modules would then check the scanner's cache for a respective discovered module, and if no such module is found the "loader" would search the filesystem.
This meant that in practice, we searched the filesystem on many occasions where we actually had cached the required dependency, as follows:
Suppose we had previously discovered a Clang module "foo" and cached its dependency info.
-> ASTContext.getModuleDependencies("foo")
--> (1) Swift Module "Loader" checks caches for a Swift module "foo" and doesn't find one, so it searches the filesystem for "foo" and fails to find one.
--> (2) Clang Module "Loader" checks caches for a Clang module "foo", finds one and returns it to the client.
This means that we were always searching the filesystem in (1) even if we knew that to be futile.
With this change, queries to `ASTContext`'s `getModuleDependencies` will always check all the caches first, and only delegate to the scanner "loaders" if no cached dependency is found. The loaders are then no longer in the business of checking the cached contents.
To handle cases in the scanner where we must only lookup either a Swift-only module or a Clang-only module, this patch splits 'getModuleDependencies' into an alrady-existing 'getSwiftModuleDependencies' and a newly-added 'getClangModuleDependencies'.
