With the growing popularity of using Features, I think it's important to
ensure our Features querying set is as fast as possible. In particular,
we sometimes may end up putting a feature check in a hot function, so
the `contains` overhead is important.
While I haven't done *any* measurements to verify this, I think a
`llvm::SmallSet<Feature, 2>` is slower than a FixedBitSet. For the
former, if the set grows more than the constant size, it switches over
to using a `std::set`. Setting the size to `numFeatures()` is not
particularly attractive or possible, because `SmallSet` is limited to a
size of 32 to be considered small, as it uses linear search over a
SmallVector to service a `contains` query.
Meanwhile, a FixedBitSet has a small constant factor overhead for
querying if the element is contained: two divisions by a
constant power-of-two, a bit shift, and a memory-read / compare. I think
that'll beat a SmallSet in all cases.
Conflicts:
- `lib/AST/TypeCheckRequests.cpp` renamed `isMoveOnly` which requires
a static_cast on rebranch because `Optional` is now a `std::optional`.
By default the compiler will now replace the bodies of unavailable functions
with stubs that call `_diagnoseUnavailableCodeReached()` instead.
Resolves rdar://116019744
Using `-Rmodule-api-import` the compiler prints a remark about the
import bringing in every decl used in public function signatures or
inlinable code. It also remarks on the source of conformances where they
are used and the source of typealias underlying types.
An existing test (Frontend/skip-function-bodies.swift) was designed under the
assumption that multiple `-debug-forbid-typecheck-prefix` arguments were
already supported, and as a result the test was not actually asserting what it
was written to assert.
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.
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
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
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.
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.
Lazy member loading has been in use and the default for several years
now. However, the lazy loading was disabled for any type whose primary
definition was parsed even though some of its extensions could have
been deserialized, e.g., from a Clang module. Moreover, the non-lazy
path walked all of the extensions of such a type for all member name
lookup operations. Faced with a large number of extensions to the same
type (in my example, 6,000), this walk of the list of the extensions
could dominate type-checking time.
Eliminate all effects of the `-disable-named-lazy-member-loading`
flag, and always use the "lazy" path, which effectively does no work
for parsed type definitions and extensions thereof. The example with
6,000 extensions of a single type goes from type checking in 6 seconds
down to type checking in 0.6 seconds, and name lookup completely
disappears from the profiling trace.
The deleted tests relied on the flag that is now inert. They aren't by
themselves providing much value nowadays, and it's better to have the
simpler (and more efficient) implementation of member name lookup be
the only one.
Intro a deserialization mode controlled by the flag
`-experimental-force-workaround-broken-modules` to attempt unsafe
recovery from deserialization failures caused by project issues.
The one issue handled at this time is when a type moves from one module
to another. With this new mode the compiler may be able to pick a
matching type in a different module. This is risky to use, but may help
in a pinch for a client to fix and issue in a library over which they
have no control.
Deserialization recovery silently drops errors and the affected decls.
This can lead to surprises when a function from an imported module
simply disappears without an explanation.
This commit introduces the flag -Rmodule-recovery to report as remarks
some of these previously silently dropped issues. It can be used to
debug project configuration issues.
This will mean that '-disable-implicit-swift-modules' also automatically implies two things:
1. Clang modules must also be explicit, and the importer's clang instance will get '-fno-implicit-modules' and '-fno-implicit-module-maps'
2. The importer's clang instance will no longer get a '-fmodules-cache-path=', since it is not needed in explicit builds
Teach swift compiler about CAS to allow compiler caching in the future.
1) Add flags to initiate CAS inside swift-frontend
2) Teach swift to compile using a CAS file system.
Previously we would only enable by default when
`parseArgs` was called. However this wouldn't
enable it for clients such as LLDB, who provide
their own invocation. Switch the default to `true`
in the `LangOptions`, and remove some redundant
uses of `-enable-experimental-string-processing`.
The frontend flag remains, as it may be useful to
disable.
rdar://107419385
rdar://101765556
