In the refactoring change #76700, it accidentally introduced a behavior
change that causes the generated PCM command-line to have useful
VFSOverlay files getting dropped. Clang module command-line and its
unused VFS pruning should be done by the clang dependency scanner
already so there is no need to touch that in the swift scanner. Since
the original logics is not used to handle clang module commands, it will
actually dropped the useful vfs overlay that is needed when none of the
dependencies uses it. Fix the regression by restoring the old behavior
and ignoring clang modules when pruning VFS overlay.
rdar://139233781
Instead, each scan's 'ModuleDependenciesCache' will hold all of the data corresponding to discovered module dependencies.
The initial design presumed the possibility of sharing a global scanning cache amongs different scanner invocations, possibly even different concurrent scanner invocations.
This change also deprecates two libSwiftScan entry-points: 'swiftscan_scanner_cache_load' and 'swiftscan_scanner_cache_serialize'. They never ended up getting used, and since this code has been largely stale, we are confident they have not otherwise had users, and they do not fit with this design.
A follow-up change will re-introduce moduele dependency cache serialization on a per-query basis and bring the binary format up-to-date.
Teach dependency scanner to construct build commands using resolved
plugin search path option. This ensures the modules that do not have
access to the macro plugins will not have a different variant due to
different plugin search path.
rdar://136682810
This change refactors the top-level dependency scanning flow to follow the following procedure:
Scan():
1. From the source target under scan, query all imported module identifiers for a *Swift* module. Leave unresolved identifiers unresolved. Proceed transitively to build a *Swift* module dependency graph.
2. Take every unresolved import identifier in the graph from (1) and, assuming that it must be a Clang module, dispatch all of them to be queried in-parallel by the scanner's worker pool.
3. Resolve bridging header Clang module dpendencies
4. Resolve all Swift overlay dependencies, relying on all Clang modules collected in (2) and (3)
5. For the source target under scan, use all of the above discovered module dependencies to resolve all cross-import overlay dependencies
Use IncludeTreeFileList instead of full feature CASFS for swift
dependency filesystem. This allows smaller CAS based VFS that is smaller
and faster. This is enabled by the CAS enabled compilation does not
need to iterate file system.
rdar://136787368
Rewrite part of the dependency scanner into a class so it is easier to
keep track of the global states and avoid redundent work. This allows
folding the pruning unused VFS job into the same loop and reduce a lot
of repeated dependency cache updates.
Add function to handle all macro dependencies kinds in the scanner,
including taking care of the macro definitions in the module interface
for its client to use. The change involves:
* Encode the macro definition inside the binary module
* Resolve macro modules in the dependencies scanners, including those
declared inside the dependency modules.
* Propagate the macro defined from the direct dependencies to track
all the potentially available modules inside a module compilation.
Fix a bug that the index is not incremented in the loop, causing
malformed swift dependencies graph when more than one macro dependency
is found inside one module.
Fix a bug that when the last argument is removed as macro search
options, the iterator increment afterwards is going to bring it pass the
end of the container.
rdar://135366279
When scanning swift modules and constructing their build commands, there
is no need to pass any external plugin search paths if there are no macro
dependencies for the module.
rdar://135221984
This makes sure that Swift respects `-Xcc -stdlib=libc++` flags.
Clang already has existing logic to discover the system-wide libc++ installation on Linux. We rely on that logic here.
Importing a Swift module that was built with a different C++ stdlib is not supported and emits an error.
The Cxx module can be imported when compiling with any C++ stdlib. The synthesized conformances, e.g. to CxxRandomAccessCollection also work. However, CxxStdlib currently cannot be imported when compiling with libc++, since on Linux it refers to symbols from libstdc++ which have different mangled names in libc++.
rdar://118357548 / https://github.com/swiftlang/swift/issues/69825
Conflicts:
- `test/Interop/Cxx/class/method/methods-this-and-indirect-return-irgen-itanium.swift`
previously fixed on rebranch, now fixed on main (slightly differently).
The scanning action does not have any need for handling `-llvm` options, since it will never perform any code-gen. LLVM option processing relies on global option parsing structures, and the scanner has needed to carefully attempt to synchronize access to them. This change guards the configuration of LLVM options to not happen at all for dependency scanning actions, and removes calls to `llvm::cl::ResetAllOptionOccurrences()` that were previously needed.
Resolves rdar://120754696
Fix few issues from previous implementation from explicit module build
with macros and accurate macro dependency scanning in
https://github.com/swiftlang/swift/pull/73421.
First, there is a crash when propagating the macro dependencies. It
turns out that the current macro plugin implementation doesn't need the
downstream users to know about the plugin search path from the upstream
dependencies.
Secondly, fix a bug that the swiftinterface that has macro usage won't
build because the build command doesn't inherit the plugin search path
option.
Finally, add JSON output for macro dependencies so it is easier to
debug the macro dependencies.
rdar://131214106
Remove `deque` from files it isn't actually used in. Add it and `stack`
to files that it is - presumably they were previously transitively found
through other includes.
Build an accurate macro dependency for swift caching. Specifically, do
not include not used macro plugins into the dependency, which might
cause false negatives for cache hits.
This also builds the foundation for future improvement when dependency
scanning will determine the macro plugin to load and swift-frontend do
not need to redo the work.
rdar://127116512
Although I don't plan to bring over new assertions wholesale
into the current qualification branch, it's entirely possible
that various minor changes in main will use the new assertions;
having this basic support in the release branch will simplify that.
(This is why I'm adding the includes as a separate pass from
rewriting the individual assertions)
Teach scanner to respect the working directory set in the invocation
through scanner C API.
Also add test infrastructure to testing scanner from C API. Break up
DependencyScan lib into two so the swift-scan-test and remain small
without understanding swift AST.
rdar://127626011
This change modifies the dependency scanner to keep track of source locations of each encountered 'import' statement, in order to be able to emit diagnostics with source locations if an import failed to resolve.
- Keep track of each 'import' statement's source buffer, line number, and column number when adding it. The dependency scanner utilizes separate compilation instances, and therefore separate Source Managers for scanning `import` statements of user sources and textual interfaces of Swift dependencies. Since import resolution may happen in the main scanner compilation instance while the `import` itself was found by an interface-scanning sub-instance, we cannot simply hold on to the import's `SourceLoc`.
- Add libSwiftScan API for diagnostics to carry above source locations to clients.
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
