Use boolOrDefault to distinguish betweeen options that are unset and
those that are set (to some value). Then, only override the default
values in SILOptions when the options are specified.
Replaced the -disable-copy-propagation flag with
-enable-copy-propagation=false where the latter is a new multi-var
-enable-copy-propagation= which can take one of three values:
- true
- requested-passes-only
- false
Previously, the default value for SILOptions::LexicalLifetimes was based
on a copy propagation behavior (which can then be overridden by the
flags for lexical lifetimems) only when the copy propagation was
explicitly specified. Instead, set base the default value for this
option (SILOptions::LexicalLifetimes) on the effective copy propagation
behavior (i.e. SILOptions::CopyPropagation) regardless of whether an
explicit behavior has been specified.
Doing so will ensure that the desired behavior occurs as the default
behavior for copy-propagation changes, but for now this change is NFC.
Now that arguments are marked up with whether they have a default or
not, clients may not need the extra call (that has no default
arguments). Add an option to allow not adding this item.
Resolves rdar://85526214.
When looking for a Swift module on disk, we were scanning all module search paths if they contain the module we are searching for. In a setup where each module is contained in its own framework search path, this scaled quadratically with the number of modules being imported. E.g. a setup with 100 modules being imported form 100 module search paths could cause on the order of 10,000 checks of `FileSystem::exists`. While these checks are fairly fast (~10µs), they add up to ~100ms.
To improve this, perform a first scan of all module search paths and list the files they contain. From this, create a lookup map that maps filenames to the search paths they can be found in. E.g. for
```
searchPath1/
Module1.framework
searchPath2/
Module1.framework
Module2.swiftmodule
```
we create the following lookup table
```
Module1.framework -> [searchPath1, searchPath2]
Module2.swiftmodule -> [searchPath2]
```
When opening a file for the first time, we don’t store a snapshot for it. This could cause a crash when trying to consult its snapshot to see whether an AST can be reused for cursor info.
Instead of checking that the stdlib can be loaded in a variety of places, check it when setting up the compiler instance. This required a couple more checks to avoid loading the stdlib in cases where it’s not needed.
To be able to differentiate stdlib loading failures from other setup errors, make `CompilerInstance::setup` return an error message on failure via an inout parameter. Consume that error on the call side, replacing a previous, more generic error message, adding error handling where appropriate or ignoring the error message, depending on the context.
Enqueuing `SwiftASTConsumer`s might be expensive because `getBuildOperationForConsumer` consults the file system. Since all results from the AST build are processed asynchronously anyway, there’s no need to perform the enqueuing synchronously.
rdar://86289703
The effect of passing -enable-copy-propagation is both to enable the
CopyPropagation pass to shorten object lifetimes and also to enable
lexical lifetimes to ensure that object lifetimes aren't shortened while
a variable is still in scope and used.
Add a new flag, -enable-lexical-borrow-scopes=true to override
-enable-copy-propagation's effect (setting it to ::ExperimentalLate) on
SILOptions::LexicalLifetimes that sets it to ::Early even in the face of
-enable-copy-propagation. The old flag -disable-lexical-lifetimes is
renamed to -enable-lexical-borrow-scopes=false but continues to set that
option to ::Off even when -enable-copy-propagation is passed.
We never need to have two copies of the same `FileContent` object, so we don’t need a copy constructor and can thus pass it on the stack again, instead of storing it on the heap.
