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llvm-project/clang-tools-extra/clangd/TUScheduler.cpp

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//===--- TUScheduler.cpp -----------------------------------------*-C++-*-===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
// TUScheduler manages a worker per active file. This ASTWorker processes
// updates (modifications to file contents) and reads (actions performed on
// preamble/AST) to the file.
//
// Each ASTWorker owns a dedicated thread to process updates and reads to the
// relevant file. Any request gets queued in FIFO order to be processed by that
// thread.
//
// An update request replaces current praser inputs to ensure any subsequent
// read sees the version of the file they were requested. It will also issue a
// build for new inputs.
//
// ASTWorker processes the file in two parts, a preamble and a main-file
// section. A preamble can be reused between multiple versions of the file until
// invalidated by a modification to a header, compile commands or modification
// to relevant part of the current file. Such a preamble is called compatible.
// An update is considered dead if no read was issued for that version and
// diagnostics weren't requested by client or could be generated for a later
// version of the file. ASTWorker eliminates such requests as they are
// redundant.
//
// In the presence of stale (non-compatible) preambles, ASTWorker won't publish
// diagnostics for update requests. Read requests will be served with ASTs build
// with stale preambles, unless the read is picky and requires a compatible
// preamble. In such cases it will block until new preamble is built.
//
// ASTWorker owns a PreambleThread for building preambles. If the preamble gets
// invalidated by an update request, a new build will be requested on
// PreambleThread. Since PreambleThread only receives requests for newer
// versions of the file, in case of multiple requests it will only build the
// last one and skip requests in between. Unless client force requested
// diagnostics(WantDiagnostics::Yes).
//
// When a new preamble is built, a "golden" AST is immediately built from that
// version of the file. This ensures diagnostics get updated even if the queue
// is full.
//
// Some read requests might just need preamble. Since preambles can be read
// concurrently, ASTWorker runs these requests on their own thread. These
// requests will receive latest build preamble, which might possibly be stale.
#include "TUScheduler.h"
#include "Compiler.h"
#include "Diagnostics.h"
#include "GlobalCompilationDatabase.h"
#include "ParsedAST.h"
#include "Preamble.h"
#include "index/CanonicalIncludes.h"
#include "support/Cancellation.h"
#include "support/Context.h"
#include "support/Logger.h"
#include "support/MemoryTree.h"
#include "support/Path.h"
#include "support/Threading.h"
#include "support/Trace.h"
#include "clang/Frontend/CompilerInvocation.h"
#include "clang/Tooling/CompilationDatabase.h"
#include "llvm/ADT/FunctionExtras.h"
#include "llvm/ADT/None.h"
#include "llvm/ADT/Optional.h"
#include "llvm/ADT/STLExtras.h"
#include "llvm/ADT/ScopeExit.h"
#include "llvm/ADT/SmallVector.h"
#include "llvm/ADT/StringExtras.h"
#include "llvm/ADT/StringRef.h"
#include "llvm/Support/Errc.h"
#include "llvm/Support/ErrorHandling.h"
#include "llvm/Support/FormatVariadic.h"
#include "llvm/Support/Path.h"
#include "llvm/Support/Threading.h"
#include <algorithm>
#include <chrono>
#include <condition_variable>
#include <functional>
#include <memory>
#include <mutex>
#include <queue>
#include <string>
#include <thread>
#include <type_traits>
#include <utility>
#include <vector>
namespace clang {
namespace clangd {
using std::chrono::steady_clock;
namespace {
class ASTWorker;
} // namespace
static clang::clangd::Key<std::string> kFileBeingProcessed;
llvm::Optional<llvm::StringRef> TUScheduler::getFileBeingProcessedInContext() {
if (auto *File = Context::current().get(kFileBeingProcessed))
return llvm::StringRef(*File);
return None;
}
/// An LRU cache of idle ASTs.
/// Because we want to limit the overall number of these we retain, the cache
/// owns ASTs (and may evict them) while their workers are idle.
/// Workers borrow ASTs when active, and return them when done.
class TUScheduler::ASTCache {
public:
using Key = const ASTWorker *;
ASTCache(unsigned MaxRetainedASTs) : MaxRetainedASTs(MaxRetainedASTs) {}
/// Returns result of getUsedBytes() for the AST cached by \p K.
/// If no AST is cached, 0 is returned.
std::size_t getUsedBytes(Key K) {
std::lock_guard<std::mutex> Lock(Mut);
auto It = findByKey(K);
if (It == LRU.end() || !It->second)
return 0;
return It->second->getUsedBytes();
}
/// Store the value in the pool, possibly removing the last used AST.
/// The value should not be in the pool when this function is called.
void put(Key K, std::unique_ptr<ParsedAST> V) {
std::unique_lock<std::mutex> Lock(Mut);
assert(findByKey(K) == LRU.end());
LRU.insert(LRU.begin(), {K, std::move(V)});
if (LRU.size() <= MaxRetainedASTs)
return;
// We're past the limit, remove the last element.
std::unique_ptr<ParsedAST> ForCleanup = std::move(LRU.back().second);
LRU.pop_back();
// Run the expensive destructor outside the lock.
Lock.unlock();
ForCleanup.reset();
}
/// Returns the cached value for \p K, or llvm::None if the value is not in
/// the cache anymore. If nullptr was cached for \p K, this function will
/// return a null unique_ptr wrapped into an optional.
/// If \p AccessMetric is set records whether there was a hit or miss.
llvm::Optional<std::unique_ptr<ParsedAST>>
take(Key K, const trace::Metric *AccessMetric = nullptr) {
// Record metric after unlocking the mutex.
std::unique_lock<std::mutex> Lock(Mut);
auto Existing = findByKey(K);
if (Existing == LRU.end()) {
if (AccessMetric)
AccessMetric->record(1, "miss");
return None;
}
if (AccessMetric)
AccessMetric->record(1, "hit");
std::unique_ptr<ParsedAST> V = std::move(Existing->second);
LRU.erase(Existing);
// GCC 4.8 fails to compile `return V;`, as it tries to call the copy
// constructor of unique_ptr, so we call the move ctor explicitly to avoid
// this miscompile.
return llvm::Optional<std::unique_ptr<ParsedAST>>(std::move(V));
}
private:
using KVPair = std::pair<Key, std::unique_ptr<ParsedAST>>;
std::vector<KVPair>::iterator findByKey(Key K) {
return llvm::find_if(LRU, [K](const KVPair &P) { return P.first == K; });
}
std::mutex Mut;
unsigned MaxRetainedASTs;
/// Items sorted in LRU order, i.e. first item is the most recently accessed
/// one.
std::vector<KVPair> LRU; /* GUARDED_BY(Mut) */
};
namespace {
/// Threadsafe manager for updating a TUStatus and emitting it after each
/// update.
class SynchronizedTUStatus {
public:
SynchronizedTUStatus(PathRef FileName, ParsingCallbacks &Callbacks)
: FileName(FileName), Callbacks(Callbacks) {}
void update(llvm::function_ref<void(TUStatus &)> Mutator) {
std::lock_guard<std::mutex> Lock(StatusMu);
Mutator(Status);
emitStatusLocked();
}
/// Prevents emitting of further updates.
void stop() {
std::lock_guard<std::mutex> Lock(StatusMu);
CanPublish = false;
}
private:
void emitStatusLocked() {
if (CanPublish)
Callbacks.onFileUpdated(FileName, Status);
}
const Path FileName;
std::mutex StatusMu;
TUStatus Status;
bool CanPublish = true;
ParsingCallbacks &Callbacks;
};
/// Responsible for building preambles. Whenever the thread is idle and the
/// preamble is outdated, it starts to build a fresh preamble from the latest
/// inputs. If RunSync is true, preambles are built synchronously in update()
/// instead.
class PreambleThread {
public:
PreambleThread(llvm::StringRef FileName, ParsingCallbacks &Callbacks,
bool StorePreambleInMemory, bool RunSync,
SynchronizedTUStatus &Status, ASTWorker &AW)
: FileName(FileName), Callbacks(Callbacks),
StoreInMemory(StorePreambleInMemory), RunSync(RunSync), Status(Status),
ASTPeer(AW) {}
/// It isn't guaranteed that each requested version will be built. If there
/// are multiple update requests while building a preamble, only the last one
/// will be built.
void update(std::unique_ptr<CompilerInvocation> CI, ParseInputs PI,
std::vector<Diag> CIDiags, WantDiagnostics WantDiags) {
Request Req = {std::move(CI), std::move(PI), std::move(CIDiags), WantDiags,
Context::current().clone()};
if (RunSync) {
build(std::move(Req));
Status.update([](TUStatus &Status) {
Status.PreambleActivity = PreambleAction::Idle;
});
return;
}
{
std::unique_lock<std::mutex> Lock(Mutex);
// If NextReq was requested with WantDiagnostics::Yes we cannot just drop
// that on the floor. Block until we start building it. This won't
// dead-lock as we are blocking the caller thread, while builds continue
// on preamble thread.
ReqCV.wait(Lock, [this] {
return !NextReq || NextReq->WantDiags != WantDiagnostics::Yes;
});
NextReq = std::move(Req);
}
// Let the worker thread know there's a request, notify_one is safe as there
// should be a single worker thread waiting on it.
ReqCV.notify_all();
}
void run() {
while (true) {
{
std::unique_lock<std::mutex> Lock(Mutex);
assert(!CurrentReq && "Already processing a request?");
// Wait until stop is called or there is a request.
ReqCV.wait(Lock, [this] { return NextReq || Done; });
if (Done)
break;
CurrentReq = std::move(*NextReq);
NextReq.reset();
}
{
WithContext Guard(std::move(CurrentReq->Ctx));
// Note that we don't make use of the ContextProvider here.
// Preamble tasks are always scheduled by ASTWorker tasks, and we
// reuse the context/config that was created at that level.
// Build the preamble and let the waiters know about it.
build(std::move(*CurrentReq));
}
bool IsEmpty = false;
{
std::lock_guard<std::mutex> Lock(Mutex);
CurrentReq.reset();
IsEmpty = !NextReq.hasValue();
}
if (IsEmpty) {
// We don't perform this above, before waiting for a request to make
// tests more deterministic. As there can be a race between this thread
// and client thread(clangdserver).
Status.update([](TUStatus &Status) {
Status.PreambleActivity = PreambleAction::Idle;
});
}
ReqCV.notify_all();
}
dlog("Preamble worker for {0} stopped", FileName);
}
/// Signals the run loop to exit.
void stop() {
dlog("Preamble worker for {0} received stop", FileName);
{
std::lock_guard<std::mutex> Lock(Mutex);
Done = true;
NextReq.reset();
}
// Let the worker thread know that it should stop.
ReqCV.notify_all();
}
bool blockUntilIdle(Deadline Timeout) const {
std::unique_lock<std::mutex> Lock(Mutex);
return wait(Lock, ReqCV, Timeout, [&] { return !NextReq && !CurrentReq; });
}
private:
/// Holds inputs required for building a preamble. CI is guaranteed to be
/// non-null.
struct Request {
std::unique_ptr<CompilerInvocation> CI;
ParseInputs Inputs;
std::vector<Diag> CIDiags;
WantDiagnostics WantDiags;
Context Ctx;
};
bool isDone() {
std::lock_guard<std::mutex> Lock(Mutex);
return Done;
}
/// Builds a preamble for \p Req, might reuse LatestBuild if possible.
/// Notifies ASTWorker after build finishes.
void build(Request Req);
mutable std::mutex Mutex;
bool Done = false; /* GUARDED_BY(Mutex) */
llvm::Optional<Request> NextReq; /* GUARDED_BY(Mutex) */
llvm::Optional<Request> CurrentReq; /* GUARDED_BY(Mutex) */
// Signaled whenever a thread populates NextReq or worker thread builds a
// Preamble.
mutable std::condition_variable ReqCV; /* GUARDED_BY(Mutex) */
// Accessed only by preamble thread.
std::shared_ptr<const PreambleData> LatestBuild;
const Path FileName;
ParsingCallbacks &Callbacks;
const bool StoreInMemory;
const bool RunSync;
SynchronizedTUStatus &Status;
ASTWorker &ASTPeer;
};
class ASTWorkerHandle;
/// Owns one instance of the AST, schedules updates and reads of it.
/// Also responsible for building and providing access to the preamble.
/// Each ASTWorker processes the async requests sent to it on a separate
/// dedicated thread.
/// The ASTWorker that manages the AST is shared by both the processing thread
/// and the TUScheduler. The TUScheduler should discard an ASTWorker when
/// remove() is called, but its thread may be busy and we don't want to block.
/// So the workers are accessed via an ASTWorkerHandle. Destroying the handle
/// signals the worker to exit its run loop and gives up shared ownership of the
/// worker.
class ASTWorker {
friend class ASTWorkerHandle;
ASTWorker(PathRef FileName, const GlobalCompilationDatabase &CDB,
TUScheduler::ASTCache &LRUCache, Semaphore &Barrier, bool RunSync,
const TUScheduler::Options &Opts, ParsingCallbacks &Callbacks);
public:
/// Create a new ASTWorker and return a handle to it.
/// The processing thread is spawned using \p Tasks. However, when \p Tasks
/// is null, all requests will be processed on the calling thread
/// synchronously instead. \p Barrier is acquired when processing each
/// request, it is used to limit the number of actively running threads.
static ASTWorkerHandle create(PathRef FileName,
const GlobalCompilationDatabase &CDB,
TUScheduler::ASTCache &IdleASTs,
AsyncTaskRunner *Tasks, Semaphore &Barrier,
const TUScheduler::Options &Opts,
ParsingCallbacks &Callbacks);
~ASTWorker();
void update(ParseInputs Inputs, WantDiagnostics);
void
runWithAST(llvm::StringRef Name,
llvm::unique_function<void(llvm::Expected<InputsAndAST>)> Action,
TUScheduler::ASTActionInvalidation);
bool blockUntilIdle(Deadline Timeout) const;
std::shared_ptr<const PreambleData> getPossiblyStalePreamble() const;
/// Used to inform ASTWorker about a new preamble build by PreambleThread.
/// Diagnostics are only published through this callback. This ensures they
/// are always for newer versions of the file, as the callback gets called in
/// the same order as update requests.
void updatePreamble(std::unique_ptr<CompilerInvocation> CI, ParseInputs PI,
std::shared_ptr<const PreambleData> Preamble,
std::vector<Diag> CIDiags, WantDiagnostics WantDiags);
/// Obtain a preamble reflecting all updates so far. Threadsafe.
/// It may be delivered immediately, or later on the worker thread.
void getCurrentPreamble(
llvm::unique_function<void(std::shared_ptr<const PreambleData>)>);
/// Returns compile command from the current file inputs.
tooling::CompileCommand getCurrentCompileCommand() const;
/// Wait for the first build of preamble to finish. Preamble itself can be
/// accessed via getPossiblyStalePreamble(). Note that this function will
/// return after an unsuccessful build of the preamble too, i.e. result of
/// getPossiblyStalePreamble() can be null even after this function returns.
void waitForFirstPreamble() const;
TUScheduler::FileStats stats() const;
bool isASTCached() const;
private:
/// Publishes diagnostics for \p Inputs. It will build an AST or reuse the
/// cached one if applicable. Assumes LatestPreamble is compatible for \p
/// Inputs.
void generateDiagnostics(std::unique_ptr<CompilerInvocation> Invocation,
ParseInputs Inputs, std::vector<Diag> CIDiags);
// Must be called exactly once on processing thread. Will return after
// stop() is called on a separate thread and all pending requests are
// processed.
void run();
/// Signal that run() should finish processing pending requests and exit.
void stop();
/// Adds a new task to the end of the request queue.
void startTask(llvm::StringRef Name, llvm::unique_function<void()> Task,
llvm::Optional<WantDiagnostics> UpdateType,
TUScheduler::ASTActionInvalidation);
/// Determines the next action to perform.
/// All actions that should never run are discarded.
/// Returns a deadline for the next action. If it's expired, run now.
/// scheduleLocked() is called again at the deadline, or if requests arrive.
Deadline scheduleLocked();
/// Should the first task in the queue be skipped instead of run?
bool shouldSkipHeadLocked() const;
struct Request {
llvm::unique_function<void()> Action;
std::string Name;
steady_clock::time_point AddTime;
Context Ctx;
llvm::Optional<WantDiagnostics> UpdateType;
TUScheduler::ASTActionInvalidation InvalidationPolicy;
Canceler Invalidate;
};
/// Handles retention of ASTs.
TUScheduler::ASTCache &IdleASTs;
const bool RunSync;
/// Time to wait after an update to see whether another update obsoletes it.
const DebouncePolicy UpdateDebounce;
/// File that ASTWorker is responsible for.
const Path FileName;
/// Callback to create processing contexts for tasks.
const std::function<Context(llvm::StringRef)> ContextProvider;
const GlobalCompilationDatabase &CDB;
/// Callback invoked when preamble or main file AST is built.
ParsingCallbacks &Callbacks;
Semaphore &Barrier;
/// Whether the 'onMainAST' callback ran for the current FileInputs.
bool RanASTCallback = false;
/// Guards members used by both TUScheduler and the worker thread.
mutable std::mutex Mutex;
/// File inputs, currently being used by the worker.
/// Writes and reads from unknown threads are locked. Reads from the worker
/// thread are not locked, as it's the only writer.
ParseInputs FileInputs; /* GUARDED_BY(Mutex) */
/// Times of recent AST rebuilds, used for UpdateDebounce computation.
llvm::SmallVector<DebouncePolicy::clock::duration, 8>
RebuildTimes; /* GUARDED_BY(Mutex) */
/// Set to true to signal run() to finish processing.
bool Done; /* GUARDED_BY(Mutex) */
std::deque<Request> Requests; /* GUARDED_BY(Mutex) */
llvm::Optional<Request> CurrentRequest; /* GUARDED_BY(Mutex) */
/// Signalled whenever a new request has been scheduled or processing of a
/// request has completed.
mutable std::condition_variable RequestsCV;
/// Latest build preamble for current TU.
/// None means no builds yet, null means there was an error while building.
/// Only written by ASTWorker's thread.
llvm::Optional<std::shared_ptr<const PreambleData>> LatestPreamble;
std::queue<Request> PreambleRequests; /* GUARDED_BY(Mutex) */
/// Signaled whenever LatestPreamble changes state or there's a new
/// PreambleRequest.
mutable std::condition_variable PreambleCV;
/// Guards the callback that publishes results of AST-related computations
/// (diagnostics, highlightings) and file statuses.
std::mutex PublishMu;
// Used to prevent remove document + add document races that lead to
// out-of-order callbacks for publishing results of onMainAST callback.
//
// The lifetime of the old/new ASTWorkers will overlap, but their handles
// don't. When the old handle is destroyed, the old worker will stop reporting
// any results to the user.
bool CanPublishResults = true; /* GUARDED_BY(PublishMu) */
std::atomic<unsigned> ASTBuildCount = {0};
std::atomic<unsigned> PreambleBuildCount = {0};
SynchronizedTUStatus Status;
PreambleThread PreamblePeer;
};
/// A smart-pointer-like class that points to an active ASTWorker.
/// In destructor, signals to the underlying ASTWorker that no new requests will
/// be sent and the processing loop may exit (after running all pending
/// requests).
class ASTWorkerHandle {
friend class ASTWorker;
ASTWorkerHandle(std::shared_ptr<ASTWorker> Worker)
: Worker(std::move(Worker)) {
assert(this->Worker);
}
public:
ASTWorkerHandle(const ASTWorkerHandle &) = delete;
ASTWorkerHandle &operator=(const ASTWorkerHandle &) = delete;
ASTWorkerHandle(ASTWorkerHandle &&) = default;
ASTWorkerHandle &operator=(ASTWorkerHandle &&) = default;
~ASTWorkerHandle() {
if (Worker)
Worker->stop();
}
ASTWorker &operator*() {
assert(Worker && "Handle was moved from");
return *Worker;
}
ASTWorker *operator->() {
assert(Worker && "Handle was moved from");
return Worker.get();
}
/// Returns an owning reference to the underlying ASTWorker that can outlive
/// the ASTWorkerHandle. However, no new requests to an active ASTWorker can
/// be schedule via the returned reference, i.e. only reads of the preamble
/// are possible.
std::shared_ptr<const ASTWorker> lock() { return Worker; }
private:
std::shared_ptr<ASTWorker> Worker;
};
ASTWorkerHandle ASTWorker::create(PathRef FileName,
const GlobalCompilationDatabase &CDB,
TUScheduler::ASTCache &IdleASTs,
AsyncTaskRunner *Tasks, Semaphore &Barrier,
const TUScheduler::Options &Opts,
ParsingCallbacks &Callbacks) {
std::shared_ptr<ASTWorker> Worker(new ASTWorker(
FileName, CDB, IdleASTs, Barrier, /*RunSync=*/!Tasks, Opts, Callbacks));
if (Tasks) {
Tasks->runAsync("ASTWorker:" + llvm::sys::path::filename(FileName),
[Worker]() { Worker->run(); });
Tasks->runAsync("PreambleWorker:" + llvm::sys::path::filename(FileName),
[Worker]() { Worker->PreamblePeer.run(); });
}
return ASTWorkerHandle(std::move(Worker));
}
ASTWorker::ASTWorker(PathRef FileName, const GlobalCompilationDatabase &CDB,
TUScheduler::ASTCache &LRUCache, Semaphore &Barrier,
bool RunSync, const TUScheduler::Options &Opts,
ParsingCallbacks &Callbacks)
: IdleASTs(LRUCache), RunSync(RunSync), UpdateDebounce(Opts.UpdateDebounce),
FileName(FileName), ContextProvider(Opts.ContextProvider), CDB(CDB),
Callbacks(Callbacks), Barrier(Barrier), Done(false),
Status(FileName, Callbacks),
PreamblePeer(FileName, Callbacks, Opts.StorePreamblesInMemory,
RunSync || !Opts.AsyncPreambleBuilds, Status, *this) {
// Set a fallback command because compile command can be accessed before
// `Inputs` is initialized. Other fields are only used after initialization
// from client inputs.
FileInputs.CompileCommand = CDB.getFallbackCommand(FileName);
}
ASTWorker::~ASTWorker() {
// Make sure we remove the cached AST, if any.
IdleASTs.take(this);
#ifndef NDEBUG
std::lock_guard<std::mutex> Lock(Mutex);
assert(Done && "handle was not destroyed");
assert(Requests.empty() && !CurrentRequest &&
"unprocessed requests when destroying ASTWorker");
#endif
}
void ASTWorker::update(ParseInputs Inputs, WantDiagnostics WantDiags) {
std::string TaskName = llvm::formatv("Update ({0})", Inputs.Version);
auto Task = [=]() mutable {
// Get the actual command as `Inputs` does not have a command.
// FIXME: some build systems like Bazel will take time to preparing
// environment to build the file, it would be nice if we could emit a
// "PreparingBuild" status to inform users, it is non-trivial given the
// current implementation.
if (auto Cmd = CDB.getCompileCommand(FileName))
Inputs.CompileCommand = *Cmd;
else
// FIXME: consider using old command if it's not a fallback one.
Inputs.CompileCommand = CDB.getFallbackCommand(FileName);
bool InputsAreTheSame =
std::tie(FileInputs.CompileCommand, FileInputs.Contents) ==
std::tie(Inputs.CompileCommand, Inputs.Contents);
// Cached AST is invalidated.
if (!InputsAreTheSame) {
IdleASTs.take(this);
RanASTCallback = false;
}
// Update current inputs so that subsequent reads can see them.
{
std::lock_guard<std::mutex> Lock(Mutex);
FileInputs = Inputs;
}
log("ASTWorker building file {0} version {1} with command {2}\n[{3}]\n{4}",
FileName, Inputs.Version, Inputs.CompileCommand.Heuristic,
Inputs.CompileCommand.Directory,
llvm::join(Inputs.CompileCommand.CommandLine, " "));
StoreDiags CompilerInvocationDiagConsumer;
std::vector<std::string> CC1Args;
std::unique_ptr<CompilerInvocation> Invocation = buildCompilerInvocation(
Inputs, CompilerInvocationDiagConsumer, &CC1Args);
// Log cc1 args even (especially!) if creating invocation failed.
if (!CC1Args.empty())
vlog("Driver produced command: cc1 {0}", llvm::join(CC1Args, " "));
std::vector<Diag> CompilerInvocationDiags =
CompilerInvocationDiagConsumer.take();
if (!Invocation) {
elog("Could not build CompilerInvocation for file {0}", FileName);
// Remove the old AST if it's still in cache.
IdleASTs.take(this);
RanASTCallback = false;
// Report the diagnostics we collected when parsing the command line.
Callbacks.onFailedAST(FileName, Inputs.Version,
std::move(CompilerInvocationDiags),
[&](llvm::function_ref<void()> Publish) {
// Ensure we only publish results from the worker
// if the file was not removed, making sure there
// are not race conditions.
std::lock_guard<std::mutex> Lock(PublishMu);
if (CanPublishResults)
Publish();
});
// Note that this might throw away a stale preamble that might still be
// useful, but this is how we communicate a build error.
LatestPreamble.emplace();
// Make sure anyone waiting for the preamble gets notified it could not be
// built.
PreambleCV.notify_all();
return;
}
PreamblePeer.update(std::move(Invocation), std::move(Inputs),
std::move(CompilerInvocationDiags), WantDiags);
std::unique_lock<std::mutex> Lock(Mutex);
PreambleCV.wait(Lock, [this] {
// Block until we reiceve a preamble request, unless a preamble already
// exists, as patching an empty preamble would imply rebuilding it from
// scratch.
// We block here instead of the consumer to prevent any deadlocks. Since
// LatestPreamble is only populated by ASTWorker thread.
return LatestPreamble || !PreambleRequests.empty() || Done;
});
return;
};
startTask(TaskName, std::move(Task), WantDiags, TUScheduler::NoInvalidation);
}
void ASTWorker::runWithAST(
llvm::StringRef Name,
llvm::unique_function<void(llvm::Expected<InputsAndAST>)> Action,
TUScheduler::ASTActionInvalidation Invalidation) {
// Tracks ast cache accesses for read operations.
static constexpr trace::Metric ASTAccessForRead(
"ast_access_read", trace::Metric::Counter, "result");
auto Task = [=, Action = std::move(Action)]() mutable {
if (auto Reason = isCancelled())
return Action(llvm::make_error<CancelledError>(Reason));
llvm::Optional<std::unique_ptr<ParsedAST>> AST =
IdleASTs.take(this, &ASTAccessForRead);
if (!AST) {
StoreDiags CompilerInvocationDiagConsumer;
std::unique_ptr<CompilerInvocation> Invocation =
buildCompilerInvocation(FileInputs, CompilerInvocationDiagConsumer);
// Try rebuilding the AST.
vlog("ASTWorker rebuilding evicted AST to run {0}: {1} version {2}", Name,
FileName, FileInputs.Version);
// FIXME: We might need to build a patched ast once preamble thread starts
// running async. Currently getPossiblyStalePreamble below will always
// return a compatible preamble as ASTWorker::update blocks.
llvm::Optional<ParsedAST> NewAST;
if (Invocation) {
NewAST = ParsedAST::build(FileName, FileInputs, std::move(Invocation),
CompilerInvocationDiagConsumer.take(),
getPossiblyStalePreamble());
++ASTBuildCount;
}
AST = NewAST ? std::make_unique<ParsedAST>(std::move(*NewAST)) : nullptr;
}
// Make sure we put the AST back into the LRU cache.
auto _ = llvm::make_scope_exit(
[&AST, this]() { IdleASTs.put(this, std::move(*AST)); });
// Run the user-provided action.
if (!*AST)
return Action(error(llvm::errc::invalid_argument, "invalid AST"));
vlog("ASTWorker running {0} on version {2} of {1}", Name, FileName,
FileInputs.Version);
Action(InputsAndAST{FileInputs, **AST});
};
startTask(Name, std::move(Task), /*UpdateType=*/None, Invalidation);
}
void PreambleThread::build(Request Req) {
assert(Req.CI && "Got preamble request with null compiler invocation");
const ParseInputs &Inputs = Req.Inputs;
Status.update([&](TUStatus &Status) {
Status.PreambleActivity = PreambleAction::Building;
});
auto _ = llvm::make_scope_exit([this, &Req] {
ASTPeer.updatePreamble(std::move(Req.CI), std::move(Req.Inputs),
LatestBuild, std::move(Req.CIDiags),
std::move(Req.WantDiags));
});
if (!LatestBuild || Inputs.ForceRebuild) {
vlog("Building first preamble for {0} version {1}", FileName,
Inputs.Version);
} else if (isPreambleCompatible(*LatestBuild, Inputs, FileName, *Req.CI)) {
vlog("Reusing preamble version {0} for version {1} of {2}",
LatestBuild->Version, Inputs.Version, FileName);
return;
} else {
vlog("Rebuilding invalidated preamble for {0} version {1} (previous was "
"version {2})",
FileName, Inputs.Version, LatestBuild->Version);
}
LatestBuild = clang::clangd::buildPreamble(
FileName, *Req.CI, Inputs, StoreInMemory,
[this, Version(Inputs.Version)](ASTContext &Ctx,
std::shared_ptr<clang::Preprocessor> PP,
const CanonicalIncludes &CanonIncludes) {
Callbacks.onPreambleAST(FileName, Version, Ctx, std::move(PP),
CanonIncludes);
});
}
void ASTWorker::updatePreamble(std::unique_ptr<CompilerInvocation> CI,
ParseInputs PI,
std::shared_ptr<const PreambleData> Preamble,
std::vector<Diag> CIDiags,
WantDiagnostics WantDiags) {
std::string TaskName = llvm::formatv("Build AST for ({0})", PI.Version);
// Store preamble and build diagnostics with new preamble if requested.
auto Task = [this, Preamble = std::move(Preamble), CI = std::move(CI),
PI = std::move(PI), CIDiags = std::move(CIDiags),
WantDiags = std::move(WantDiags)]() mutable {
// Update the preamble inside ASTWorker queue to ensure atomicity. As a task
// running inside ASTWorker assumes internals won't change until it
// finishes.
if (!LatestPreamble || Preamble != *LatestPreamble) {
++PreambleBuildCount;
// Cached AST is no longer valid.
IdleASTs.take(this);
RanASTCallback = false;
std::lock_guard<std::mutex> Lock(Mutex);
// LatestPreamble might be the last reference to old preamble, do not
// trigger destructor while holding the lock.
if (LatestPreamble)
std::swap(*LatestPreamble, Preamble);
else
LatestPreamble = std::move(Preamble);
}
// Notify anyone waiting for a preamble.
PreambleCV.notify_all();
// Give up our ownership to old preamble before starting expensive AST
// build.
Preamble.reset();
// We only need to build the AST if diagnostics were requested.
if (WantDiags == WantDiagnostics::No)
return;
// Report diagnostics with the new preamble to ensure progress. Otherwise
// diagnostics might get stale indefinitely if user keeps invalidating the
// preamble.
generateDiagnostics(std::move(CI), std::move(PI), std::move(CIDiags));
};
if (RunSync) {
Task();
return;
}
{
std::lock_guard<std::mutex> Lock(Mutex);
PreambleRequests.push({std::move(Task), std::move(TaskName),
steady_clock::now(), Context::current().clone(),
llvm::None, TUScheduler::NoInvalidation, nullptr});
}
PreambleCV.notify_all();
RequestsCV.notify_all();
}
void ASTWorker::generateDiagnostics(
std::unique_ptr<CompilerInvocation> Invocation, ParseInputs Inputs,
std::vector<Diag> CIDiags) {
// Tracks ast cache accesses for publishing diags.
static constexpr trace::Metric ASTAccessForDiag(
"ast_access_diag", trace::Metric::Counter, "result");
assert(Invocation);
assert(LatestPreamble);
// No need to rebuild the AST if we won't send the diagnostics.
{
std::lock_guard<std::mutex> Lock(PublishMu);
if (!CanPublishResults)
return;
}
// Used to check whether we can update AST cache.
bool InputsAreLatest =
std::tie(FileInputs.CompileCommand, FileInputs.Contents) ==
std::tie(Inputs.CompileCommand, Inputs.Contents);
// Take a shortcut and don't report the diagnostics, since they should be the
// same. All the clients should handle the lack of OnUpdated() call anyway to
// handle empty result from buildAST.
// FIXME: the AST could actually change if non-preamble includes changed,
// but we choose to ignore it.
if (InputsAreLatest && RanASTCallback)
return;
// Get the AST for diagnostics, either build it or use the cached one.
std::string TaskName = llvm::formatv("Build AST ({0})", Inputs.Version);
Status.update([&](TUStatus &Status) {
Status.ASTActivity.K = ASTAction::Building;
Status.ASTActivity.Name = std::move(TaskName);
});
// We might be able to reuse the last we've built for a read request.
// FIXME: It might be better to not reuse this AST. That way queued AST builds
// won't be required for diags.
llvm::Optional<std::unique_ptr<ParsedAST>> AST =
IdleASTs.take(this, &ASTAccessForDiag);
if (!AST || !InputsAreLatest) {
auto RebuildStartTime = DebouncePolicy::clock::now();
llvm::Optional<ParsedAST> NewAST = ParsedAST::build(
FileName, Inputs, std::move(Invocation), CIDiags, *LatestPreamble);
auto RebuildDuration = DebouncePolicy::clock::now() - RebuildStartTime;
++ASTBuildCount;
// Try to record the AST-build time, to inform future update debouncing.
// This is best-effort only: if the lock is held, don't bother.
std::unique_lock<std::mutex> Lock(Mutex, std::try_to_lock);
if (Lock.owns_lock()) {
// Do not let RebuildTimes grow beyond its small-size (i.e.
// capacity).
if (RebuildTimes.size() == RebuildTimes.capacity())
RebuildTimes.erase(RebuildTimes.begin());
RebuildTimes.push_back(RebuildDuration);
Lock.unlock();
}
Status.update([&](TUStatus &Status) {
Status.Details.ReuseAST = false;
Status.Details.BuildFailed = !NewAST.hasValue();
});
AST = NewAST ? std::make_unique<ParsedAST>(std::move(*NewAST)) : nullptr;
} else {
log("Skipping rebuild of the AST for {0}, inputs are the same.", FileName);
Status.update([](TUStatus &Status) {
Status.Details.ReuseAST = true;
Status.Details.BuildFailed = false;
});
}
// Publish diagnostics.
auto RunPublish = [&](llvm::function_ref<void()> Publish) {
// Ensure we only publish results from the worker if the file was not
// removed, making sure there are not race conditions.
std::lock_guard<std::mutex> Lock(PublishMu);
if (CanPublishResults)
Publish();
};
if (*AST) {
trace::Span Span("Running main AST callback");
Callbacks.onMainAST(FileName, **AST, RunPublish);
} else {
// Failed to build the AST, at least report diagnostics from the
// command line if there were any.
// FIXME: we might have got more errors while trying to build the
// AST, surface them too.
Callbacks.onFailedAST(FileName, Inputs.Version, CIDiags, RunPublish);
}
// AST might've been built for an older version of the source, as ASTWorker
// queue raced ahead while we were waiting on the preamble. In that case the
// queue can't reuse the AST.
if (InputsAreLatest) {
RanASTCallback = *AST != nullptr;
IdleASTs.put(this, std::move(*AST));
}
}
std::shared_ptr<const PreambleData>
ASTWorker::getPossiblyStalePreamble() const {
std::lock_guard<std::mutex> Lock(Mutex);
return LatestPreamble ? *LatestPreamble : nullptr;
}
void ASTWorker::waitForFirstPreamble() const {
std::unique_lock<std::mutex> Lock(Mutex);
PreambleCV.wait(Lock, [this] { return LatestPreamble.hasValue() || Done; });
}
tooling::CompileCommand ASTWorker::getCurrentCompileCommand() const {
std::unique_lock<std::mutex> Lock(Mutex);
return FileInputs.CompileCommand;
}
TUScheduler::FileStats ASTWorker::stats() const {
TUScheduler::FileStats Result;
Result.ASTBuilds = ASTBuildCount;
Result.PreambleBuilds = PreambleBuildCount;
// Note that we don't report the size of ASTs currently used for processing
// the in-flight requests. We used this information for debugging purposes
// only, so this should be fine.
Result.UsedBytesAST = IdleASTs.getUsedBytes(this);
if (auto Preamble = getPossiblyStalePreamble())
Result.UsedBytesPreamble = Preamble->Preamble.getSize();
return Result;
}
bool ASTWorker::isASTCached() const { return IdleASTs.getUsedBytes(this) != 0; }
void ASTWorker::stop() {
{
std::lock_guard<std::mutex> Lock(PublishMu);
CanPublishResults = false;
}
{
std::lock_guard<std::mutex> Lock(Mutex);
assert(!Done && "stop() called twice");
Done = true;
}
PreamblePeer.stop();
// We are no longer going to build any preambles, let the waiters know that.
PreambleCV.notify_all();
Status.stop();
RequestsCV.notify_all();
}
void ASTWorker::startTask(llvm::StringRef Name,
llvm::unique_function<void()> Task,
llvm::Optional<WantDiagnostics> UpdateType,
TUScheduler::ASTActionInvalidation Invalidation) {
if (RunSync) {
assert(!Done && "running a task after stop()");
trace::Span Tracer(Name + ":" + llvm::sys::path::filename(FileName));
WithContext WithProvidedContext(ContextProvider(FileName));
Task();
return;
}
{
std::lock_guard<std::mutex> Lock(Mutex);
assert(!Done && "running a task after stop()");
// Cancel any requests invalidated by this request.
if (UpdateType) {
for (auto &R : llvm::reverse(Requests)) {
if (R.InvalidationPolicy == TUScheduler::InvalidateOnUpdate)
R.Invalidate();
if (R.UpdateType)
break; // Older requests were already invalidated by the older update.
}
}
// Allow this request to be cancelled if invalidated.
Context Ctx = Context::current().derive(kFileBeingProcessed, FileName);
Canceler Invalidate = nullptr;
if (Invalidation) {
WithContext WC(std::move(Ctx));
std::tie(Ctx, Invalidate) = cancelableTask(
/*Reason=*/static_cast<int>(ErrorCode::ContentModified));
}
Requests.push_back({std::move(Task), std::string(Name), steady_clock::now(),
std::move(Ctx), UpdateType, Invalidation,
std::move(Invalidate)});
}
RequestsCV.notify_all();
}
void ASTWorker::run() {
while (true) {
{
std::unique_lock<std::mutex> Lock(Mutex);
assert(!CurrentRequest && "A task is already running, multiple workers?");
for (auto Wait = scheduleLocked(); !Wait.expired();
Wait = scheduleLocked()) {
assert(PreambleRequests.empty() &&
"Preamble updates should be scheduled immediately");
if (Done) {
if (Requests.empty())
return;
else // Even though Done is set, finish pending requests.
break; // However, skip delays to shutdown fast.
}
// Tracing: we have a next request, attribute this sleep to it.
llvm::Optional<WithContext> Ctx;
llvm::Optional<trace::Span> Tracer;
if (!Requests.empty()) {
Ctx.emplace(Requests.front().Ctx.clone());
Tracer.emplace("Debounce");
SPAN_ATTACH(*Tracer, "next_request", Requests.front().Name);
if (!(Wait == Deadline::infinity())) {
Status.update([&](TUStatus &Status) {
Status.ASTActivity.K = ASTAction::Queued;
Status.ASTActivity.Name = Requests.front().Name;
});
SPAN_ATTACH(*Tracer, "sleep_ms",
std::chrono::duration_cast<std::chrono::milliseconds>(
Wait.time() - steady_clock::now())
.count());
}
}
wait(Lock, RequestsCV, Wait);
}
// Any request in ReceivedPreambles is at least as old as the
// Requests.front(), so prefer them first to preserve LSP order.
if (!PreambleRequests.empty()) {
CurrentRequest = std::move(PreambleRequests.front());
PreambleRequests.pop();
} else {
CurrentRequest = std::move(Requests.front());
Requests.pop_front();
}
} // unlock Mutex
// It is safe to perform reads to CurrentRequest without holding the lock as
// only writer is also this thread.
{
std::unique_lock<Semaphore> Lock(Barrier, std::try_to_lock);
if (!Lock.owns_lock()) {
Status.update([&](TUStatus &Status) {
Status.ASTActivity.K = ASTAction::Queued;
Status.ASTActivity.Name = CurrentRequest->Name;
});
Lock.lock();
}
WithContext Guard(std::move(CurrentRequest->Ctx));
trace::Span Tracer(CurrentRequest->Name);
Status.update([&](TUStatus &Status) {
Status.ASTActivity.K = ASTAction::RunningAction;
Status.ASTActivity.Name = CurrentRequest->Name;
});
WithContext WithProvidedContext(ContextProvider(FileName));
CurrentRequest->Action();
}
bool IsEmpty = false;
{
std::lock_guard<std::mutex> Lock(Mutex);
CurrentRequest.reset();
IsEmpty = Requests.empty() && PreambleRequests.empty();
}
if (IsEmpty) {
Status.update([&](TUStatus &Status) {
Status.ASTActivity.K = ASTAction::Idle;
Status.ASTActivity.Name = "";
});
}
RequestsCV.notify_all();
}
}
Deadline ASTWorker::scheduleLocked() {
// Process new preambles immediately.
if (!PreambleRequests.empty())
return Deadline::zero();
if (Requests.empty())
return Deadline::infinity(); // Wait for new requests.
// Handle cancelled requests first so the rest of the scheduler doesn't.
for (auto I = Requests.begin(), E = Requests.end(); I != E; ++I) {
if (!isCancelled(I->Ctx)) {
// Cancellations after the first read don't affect current scheduling.
if (I->UpdateType == None)
break;
continue;
}
// Cancelled reads are moved to the front of the queue and run immediately.
if (I->UpdateType == None) {
Request R = std::move(*I);
Requests.erase(I);
Requests.push_front(std::move(R));
return Deadline::zero();
}
// Cancelled updates are downgraded to auto-diagnostics, and may be elided.
if (I->UpdateType == WantDiagnostics::Yes)
I->UpdateType = WantDiagnostics::Auto;
}
while (shouldSkipHeadLocked()) {
vlog("ASTWorker skipping {0} for {1}", Requests.front().Name, FileName);
Requests.pop_front();
}
assert(!Requests.empty() && "skipped the whole queue");
// Some updates aren't dead yet, but never end up being used.
// e.g. the first keystroke is live until obsoleted by the second.
// We debounce "maybe-unused" writes, sleeping in case they become dead.
// But don't delay reads (including updates where diagnostics are needed).
for (const auto &R : Requests)
if (R.UpdateType == None || R.UpdateType == WantDiagnostics::Yes)
return Deadline::zero();
// Front request needs to be debounced, so determine when we're ready.
Deadline D(Requests.front().AddTime + UpdateDebounce.compute(RebuildTimes));
return D;
}
// Returns true if Requests.front() is a dead update that can be skipped.
bool ASTWorker::shouldSkipHeadLocked() const {
assert(!Requests.empty());
auto Next = Requests.begin();
auto UpdateType = Next->UpdateType;
if (!UpdateType) // Only skip updates.
return false;
++Next;
// An update is live if its AST might still be read.
// That is, if it's not immediately followed by another update.
if (Next == Requests.end() || !Next->UpdateType)
return false;
// The other way an update can be live is if its diagnostics might be used.
switch (*UpdateType) {
case WantDiagnostics::Yes:
return false; // Always used.
case WantDiagnostics::No:
return true; // Always dead.
case WantDiagnostics::Auto:
// Used unless followed by an update that generates diagnostics.
for (; Next != Requests.end(); ++Next)
if (Next->UpdateType == WantDiagnostics::Yes ||
Next->UpdateType == WantDiagnostics::Auto)
return true; // Prefer later diagnostics.
return false;
}
llvm_unreachable("Unknown WantDiagnostics");
}
bool ASTWorker::blockUntilIdle(Deadline Timeout) const {
auto WaitUntilASTWorkerIsIdle = [&] {
std::unique_lock<std::mutex> Lock(Mutex);
return wait(Lock, RequestsCV, Timeout, [&] {
return PreambleRequests.empty() && Requests.empty() && !CurrentRequest;
});
};
// Make sure ASTWorker has processed all requests, which might issue new
// updates to PreamblePeer.
WaitUntilASTWorkerIsIdle();
// Now that ASTWorker processed all requests, ensure PreamblePeer has served
// all update requests. This might create new PreambleRequests for the
// ASTWorker.
PreamblePeer.blockUntilIdle(Timeout);
assert(Requests.empty() &&
"No new normal tasks can be scheduled concurrently with "
"blockUntilIdle(): ASTWorker isn't threadsafe");
// Finally make sure ASTWorker has processed all of the preamble updates.
return WaitUntilASTWorkerIsIdle();
}
// Render a TUAction to a user-facing string representation.
// TUAction represents clangd-internal states, we don't intend to expose them
// to users (say C++ programmers) directly to avoid confusion, we use terms that
// are familiar by C++ programmers.
std::string renderTUAction(const PreambleAction PA, const ASTAction &AA) {
llvm::SmallVector<std::string, 2> Result;
switch (PA) {
case PreambleAction::Building:
Result.push_back("parsing includes");
break;
case PreambleAction::Idle:
// We handle idle specially below.
break;
}
switch (AA.K) {
case ASTAction::Queued:
Result.push_back("file is queued");
break;
case ASTAction::RunningAction:
Result.push_back("running " + AA.Name);
break;
case ASTAction::Building:
Result.push_back("parsing main file");
break;
case ASTAction::Idle:
// We handle idle specially below.
break;
}
if (Result.empty())
return "idle";
return llvm::join(Result, ",");
}
} // namespace
unsigned getDefaultAsyncThreadsCount() {
return llvm::heavyweight_hardware_concurrency().compute_thread_count();
}
FileStatus TUStatus::render(PathRef File) const {
FileStatus FStatus;
FStatus.uri = URIForFile::canonicalize(File, /*TUPath=*/File);
FStatus.state = renderTUAction(PreambleActivity, ASTActivity);
return FStatus;
}
struct TUScheduler::FileData {
/// Latest inputs, passed to TUScheduler::update().
std::string Contents;
ASTWorkerHandle Worker;
};
TUScheduler::TUScheduler(const GlobalCompilationDatabase &CDB,
const Options &Opts,
std::unique_ptr<ParsingCallbacks> Callbacks)
: CDB(CDB), Opts(Opts),
Callbacks(Callbacks ? move(Callbacks)
: std::make_unique<ParsingCallbacks>()),
Barrier(Opts.AsyncThreadsCount),
IdleASTs(
std::make_unique<ASTCache>(Opts.RetentionPolicy.MaxRetainedASTs)) {
// Avoid null checks everywhere.
if (!Opts.ContextProvider) {
this->Opts.ContextProvider = [](llvm::StringRef) {
return Context::current().clone();
};
}
if (0 < Opts.AsyncThreadsCount) {
PreambleTasks.emplace();
WorkerThreads.emplace();
}
}
TUScheduler::~TUScheduler() {
// Notify all workers that they need to stop.
Files.clear();
// Wait for all in-flight tasks to finish.
if (PreambleTasks)
PreambleTasks->wait();
if (WorkerThreads)
WorkerThreads->wait();
}
bool TUScheduler::blockUntilIdle(Deadline D) const {
for (auto &File : Files)
if (!File.getValue()->Worker->blockUntilIdle(D))
return false;
if (PreambleTasks)
if (!PreambleTasks->wait(D))
return false;
return true;
}
bool TUScheduler::update(PathRef File, ParseInputs Inputs,
WantDiagnostics WantDiags) {
std::unique_ptr<FileData> &FD = Files[File];
bool NewFile = FD == nullptr;
if (!FD) {
// Create a new worker to process the AST-related tasks.
ASTWorkerHandle Worker =
ASTWorker::create(File, CDB, *IdleASTs,
WorkerThreads ? WorkerThreads.getPointer() : nullptr,
Barrier, Opts, *Callbacks);
FD = std::unique_ptr<FileData>(
new FileData{Inputs.Contents, std::move(Worker)});
} else {
FD->Contents = Inputs.Contents;
}
FD->Worker->update(std::move(Inputs), WantDiags);
return NewFile;
}
void TUScheduler::remove(PathRef File) {
bool Removed = Files.erase(File);
if (!Removed)
elog("Trying to remove file from TUScheduler that is not tracked: {0}",
File);
}
llvm::StringMap<std::string> TUScheduler::getAllFileContents() const {
llvm::StringMap<std::string> Results;
for (auto &It : Files)
Results.try_emplace(It.getKey(), It.getValue()->Contents);
return Results;
}
void TUScheduler::run(llvm::StringRef Name, llvm::StringRef Path,
llvm::unique_function<void()> Action) {
if (!PreambleTasks) {
WithContext WithProvidedContext(Opts.ContextProvider(Path));
return Action();
}
PreambleTasks->runAsync(Name, [this, Ctx = Context::current().clone(),
Path(Path.str()),
Action = std::move(Action)]() mutable {
std::lock_guard<Semaphore> BarrierLock(Barrier);
WithContext WC(std::move(Ctx));
WithContext WithProvidedContext(Opts.ContextProvider(Path));
Action();
});
}
void TUScheduler::runWithAST(
llvm::StringRef Name, PathRef File,
llvm::unique_function<void(llvm::Expected<InputsAndAST>)> Action,
TUScheduler::ASTActionInvalidation Invalidation) {
auto It = Files.find(File);
if (It == Files.end()) {
Action(llvm::make_error<LSPError>(
"trying to get AST for non-added document", ErrorCode::InvalidParams));
return;
}
It->second->Worker->runWithAST(Name, std::move(Action), Invalidation);
}
void TUScheduler::runWithPreamble(llvm::StringRef Name, PathRef File,
PreambleConsistency Consistency,
Callback<InputsAndPreamble> Action) {
auto It = Files.find(File);
if (It == Files.end()) {
Action(llvm::make_error<LSPError>(
"trying to get preamble for non-added document",
ErrorCode::InvalidParams));
return;
}
if (!PreambleTasks) {
trace::Span Tracer(Name);
SPAN_ATTACH(Tracer, "file", File);
std::shared_ptr<const PreambleData> Preamble =
It->second->Worker->getPossiblyStalePreamble();
WithContext WithProvidedContext(Opts.ContextProvider(File));
Action(InputsAndPreamble{It->second->Contents,
It->second->Worker->getCurrentCompileCommand(),
Preamble.get()});
return;
}
std::shared_ptr<const ASTWorker> Worker = It->second->Worker.lock();
auto Task =
[Worker, Consistency, Name = Name.str(), File = File.str(),
Contents = It->second->Contents,
Command = Worker->getCurrentCompileCommand(),
Ctx = Context::current().derive(kFileBeingProcessed, std::string(File)),
Action = std::move(Action), this]() mutable {
std::shared_ptr<const PreambleData> Preamble;
if (Consistency == PreambleConsistency::Stale) {
// Wait until the preamble is built for the first time, if preamble
// is required. This avoids extra work of processing the preamble
// headers in parallel multiple times.
Worker->waitForFirstPreamble();
}
Preamble = Worker->getPossiblyStalePreamble();
std::lock_guard<Semaphore> BarrierLock(Barrier);
WithContext Guard(std::move(Ctx));
trace::Span Tracer(Name);
SPAN_ATTACH(Tracer, "file", File);
WithContext WithProvidedContext(Opts.ContextProvider(File));
Action(InputsAndPreamble{Contents, Command, Preamble.get()});
};
PreambleTasks->runAsync("task:" + llvm::sys::path::filename(File),
std::move(Task));
}
llvm::StringMap<TUScheduler::FileStats> TUScheduler::fileStats() const {
llvm::StringMap<TUScheduler::FileStats> Result;
for (const auto &PathAndFile : Files)
Result.try_emplace(PathAndFile.first(),
PathAndFile.second->Worker->stats());
return Result;
}
std::vector<Path> TUScheduler::getFilesWithCachedAST() const {
std::vector<Path> Result;
for (auto &&PathAndFile : Files) {
if (!PathAndFile.second->Worker->isASTCached())
continue;
Result.push_back(std::string(PathAndFile.first()));
}
return Result;
}
DebouncePolicy::clock::duration
DebouncePolicy::compute(llvm::ArrayRef<clock::duration> History) const {
assert(Min <= Max && "Invalid policy");
if (History.empty())
return Max; // Arbitrary.
// Base the result on the median rebuild.
// nth_element needs a mutable array, take the chance to bound the data size.
History = History.take_back(15);
llvm::SmallVector<clock::duration, 15> Recent(History.begin(), History.end());
auto Median = Recent.begin() + Recent.size() / 2;
std::nth_element(Recent.begin(), Median, Recent.end());
clock::duration Target =
std::chrono::duration_cast<clock::duration>(RebuildRatio * *Median);
if (Target > Max)
return Max;
if (Target < Min)
return Min;
return Target;
}
DebouncePolicy DebouncePolicy::fixed(clock::duration T) {
DebouncePolicy P;
P.Min = P.Max = T;
return P;
}
void TUScheduler::profile(MemoryTree &MT) const {
for (const auto &Elem : fileStats()) {
MT.detail(Elem.first())
.child("preamble")
.addUsage(Opts.StorePreamblesInMemory ? Elem.second.UsedBytesPreamble
: 0);
MT.detail(Elem.first()).child("ast").addUsage(Elem.second.UsedBytesAST);
}
}
} // namespace clangd
} // namespace clang
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