For the explicit module mode, swift-driver uses -compile-module-from-interface to
generate modules from interfaces found by the dependency scanner. However, we don't
need to build the binary module if up-to-date modules are available, either adjacent
to the interface file or in the prebuilt module cache directory. This patch teaches
dependencies scanner to report these ready-to-use binary modules.
Instead of taking paths of Swift module files from front-end command line
arguments, we should take a JSON file specifying details of explicit modules.
The advantages is (1) .swiftdoc and .swiftsourceinfo can be associated
with a .swiftmodule file, and (2) module names are explicitly used as
keys in the JSON input so we don't need to eagerly deserialize a .swiftmodule
file to collect the module name.
Building in incremental mode incurs the overhead associated with the
incremental dependency tracking infrastructure. Considering we're
throwing away all of this stuff anyways, let's just build in WMO to
avoid that.
Building each Swift module explicitly requires dependency PCMs to be built
with the exactly same deployment target version. This means we may need to
build a Clang module multiple times with different target triples.
This patch removes the -target arguments from the reported PCM build
arguments and inserts extraPcmArgs fields to each Swift module.
swift-driver can combine the generic PCM arguments with these extra arguments
to get the command suitable for building a PCM specifically for
that loading Swift module.
To support -disable-implicit-swift-modules, the explicitly built modules
are passed down as compiler arguments. We need this new module loader to
handle these modules.
This patch also stops ModuleInterfaceLoader from building module from interface
when -disable-implicit-swift-modules is set.
Module interface builder used to maintain a separate compiler instance for
building Swift modules. The configuration of this compiler instance is also
useful for dependencies scanner because it needs to emit front-end compiler invocation
for building Swift modules explicitly.
This patch refactor the configuration out to a delegate class, and the
delegate class is also used by the dependency scanner.
Additional flags in interface files may change parsing behavior like #if
statements. We should use a fresh ASTContext with these additional
flags when parsing interface files to collect imports.
rdar://62612027
* Remove dead ModuleSourceInfoFilename parameters
These were never actually used; we might find a way to bring them back later.
* Introduce SerializedModuleBaseName
This is intended to replace the _n_ filename parameters that tend to get passed around in the SerializedModuleLoader classes.
* Manipulate currPath in SerializedModuleLoader less often
* Don’t pass raw paths around SerializedModuleLoader
Only pass base names.
* Regularize module file opening functions
✔ More informative error messages in case of crashes.
✔ Handling and documenting different cases.
✔ Test cases for different cases.
✔ Make SDKDependencies.swift pass again.
We generate .swiftsourceinfo for stdlib in the build directory because ABI checker
could issue diagnostics to the stdlib source. However, this may also change other
diagnostic tests. Both Brent and Jordan have raised concern about this. After
adding this flag, other diagnostic tests could ignore .swiftsourceinfo files even
though when they are present so our tests will reflect what most users experience
when sources for stdlib are unavailable.
After setting up the .swiftsourceinfo file, this patch starts to actually serialize
and de-serialize source locations for declaration. The binary format of .swiftsourceinfo
currently contains these three records:
BasicDeclLocs: a hash table mapping from a USR ID to a list of basic source locations. The USR id
could be retrieved from the following DeclUSRs record using an actual decl USR. The basic source locations
include a file ID and the results from Decl::getLoc(), ValueDecl::getNameLoc(), Decl::getStartLoc() and Decl::getEndLoc().
The file ID could be used to retrieve the actual file name from the following SourceFilePaths record.
Each location is encoded as a line:column pair.
DeclUSRS: a hash table mapping from USR to a USR ID used by location records.
SourceFilePaths: a hash table mapping from a file ID to actual file name.
BasicDeclLocs should be sufficient for most diagnostic cases. If additional source locations
are needed, we could always add new source location records without breaking the backward compatibility.
When de-serializing the source location from a module-imported decl, we calculate its USR, retrieve the USR ID
from the DeclUSRS record, and use the USR ID to look up the basic location list in the BasicDeclLocs record.
For more details about .swiftsourceinfo file: https://forums.swift.org/t/proposal-emitting-source-information-file-during-compilation
