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[Diags] Allow multiple in-flight diagnostics #83776

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Merged
merged 3 commits into from
Sep 3, 2025
Merged

[Diags] Allow multiple in-flight diagnostics #83776

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92e6a00
[Diags] Avoid infinite recursion on decl printing request cycle
hamishknight Aug 17, 2025
45065f3
[Diags] Allow multiple in-flight diagnostics
hamishknight Aug 17, 2025
89feb8f
[Diags] Remove some now unnecessary calls to `flush`
hamishknight Aug 17, 2025
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95 changes: 59 additions & 36 deletions include/swift/AST/DiagnosticEngine.h
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Original file line number Diff line number Diff line change
Expand Up @@ -279,6 +279,19 @@ namespace swift {
}
};

namespace detail {
/// Stores information for an active diagnostic that hasn't been emitted yet.
/// This includes both "in-flight" diagnostics as well as diagnostics queued
/// for a transaction.
struct ActiveDiagnostic {
Diagnostic Diag;
SmallVector<DiagnosticInfo, 2> WrappedDiagnostics;
SmallVector<std::vector<DiagnosticArgument>, 4> WrappedDiagnosticArgs;

ActiveDiagnostic(Diagnostic diag) : Diag(std::move(diag)) {}
};
} // namespace detail

/// A diagnostic that has no input arguments, so it is trivially-destructable.
using ZeroArgDiagnostic = Diag<>;

Expand All @@ -293,33 +306,40 @@ namespace swift {
friend class DiagnosticEngine;

DiagnosticEngine *Engine;
unsigned Idx;
bool IsActive;

/// Create a new in-flight diagnostic.
///
/// This constructor is only available to the DiagnosticEngine.
InFlightDiagnostic(DiagnosticEngine &Engine)
: Engine(&Engine), IsActive(true) { }
InFlightDiagnostic(DiagnosticEngine &Engine, unsigned idx)
: Engine(&Engine), Idx(idx), IsActive(true) {}

InFlightDiagnostic(const InFlightDiagnostic &) = delete;
InFlightDiagnostic &operator=(const InFlightDiagnostic &) = delete;
InFlightDiagnostic &operator=(InFlightDiagnostic &&) = delete;

/// Retrieve the underlying active diagnostic information.
detail::ActiveDiagnostic &getActiveDiag() const;

/// Retrieve the underlying diagnostic.
Diagnostic &getDiag() const { return getActiveDiag().Diag; }

public:
/// Create an active but unattached in-flight diagnostic.
///
/// The resulting diagnostic can be used as a dummy, accepting the
/// syntax to add additional information to a diagnostic without
/// actually emitting a diagnostic.
InFlightDiagnostic() : Engine(0), IsActive(true) { }
InFlightDiagnostic() : Engine(0), Idx(0), IsActive(true) {}

/// Transfer an in-flight diagnostic to a new object, which is
/// typically used when returning in-flight diagnostics.
InFlightDiagnostic(InFlightDiagnostic &&Other)
: Engine(Other.Engine), IsActive(Other.IsActive) {
: Engine(Other.Engine), Idx(Other.Idx), IsActive(Other.IsActive) {
Other.IsActive = false;
}

~InFlightDiagnostic() {
if (IsActive)
flush();
Expand Down Expand Up @@ -784,16 +804,12 @@ namespace swift {
/// Tracks diagnostic behaviors and state
DiagnosticState state;

/// The currently active diagnostic, if there is one.
std::optional<Diagnostic> ActiveDiagnostic;

/// Diagnostics wrapped by ActiveDiagnostic, if any.
SmallVector<DiagnosticInfo, 2> WrappedDiagnostics;
SmallVector<std::vector<DiagnosticArgument>, 4> WrappedDiagnosticArgs;
/// The currently active diagnostics.
SmallVector<detail::ActiveDiagnostic, 4> ActiveDiagnostics;

/// All diagnostics that have are no longer active but have not yet
/// been emitted due to an open transaction.
SmallVector<Diagnostic, 4> TentativeDiagnostics;
SmallVector<detail::ActiveDiagnostic, 4> TentativeDiagnostics;

llvm::BumpPtrAllocator TransactionAllocator;
/// A set of all strings involved in current transactional chain.
Expand All @@ -816,6 +832,9 @@ namespace swift {
/// emitted once all transactions have closed.
unsigned TransactionCount = 0;

/// The number of currently in-flight diagnostics.
unsigned NumActiveDiags = 0;

/// For batch mode, use this to know where to output a diagnostic from a
/// non-primary file. It's any location in the buffer of the current primary
/// input being compiled.
Expand Down Expand Up @@ -851,7 +870,7 @@ namespace swift {

public:
explicit DiagnosticEngine(SourceManager &SourceMgr)
: SourceMgr(SourceMgr), ActiveDiagnostic(),
: SourceMgr(SourceMgr), ActiveDiagnostics(),
TransactionStrings(TransactionAllocator),
DiagnosticStringsSaver(DiagnosticStringsAllocator) {}

Expand All @@ -870,6 +889,7 @@ namespace swift {
}

void flushConsumers() {
ASSERT(NumActiveDiags == 0 && "Expected in-flight diags to be flushed");
for (auto consumer : Consumers)
consumer->flush();
}
Expand Down Expand Up @@ -1001,10 +1021,9 @@ namespace swift {
/// \returns An in-flight diagnostic, to which additional information can
/// be attached.
InFlightDiagnostic diagnose(SourceLoc Loc, const Diagnostic &D) {
assert(!ActiveDiagnostic && "Already have an active diagnostic");
ActiveDiagnostic = D;
ActiveDiagnostic->setLoc(Loc);
return InFlightDiagnostic(*this);
auto IFD = beginDiagnostic(D);
getActiveDiagnostic(IFD).Diag.setLoc(Loc);
return IFD;
}

/// Emit a diagnostic with the given set of diagnostic arguments.
Expand Down Expand Up @@ -1080,10 +1099,9 @@ namespace swift {
/// \returns An in-flight diagnostic, to which additional information can
/// be attached.
InFlightDiagnostic diagnose(const Decl *decl, const Diagnostic &diag) {
assert(!ActiveDiagnostic && "Already have an active diagnostic");
ActiveDiagnostic = diag;
ActiveDiagnostic->setDecl(decl);
return InFlightDiagnostic(*this);
auto IFD = beginDiagnostic(diag);
getActiveDiagnostic(IFD).Diag.setDecl(decl);
return IFD;
}

/// Emit a diagnostic with the given set of diagnostic arguments.
Expand Down Expand Up @@ -1137,16 +1155,21 @@ namespace swift {
DiagnosticFormatOptions FormatOpts = DiagnosticFormatOptions());

private:
/// Begins a new in-flight diagnostic.
InFlightDiagnostic beginDiagnostic(const Diagnostic &D);

/// Ends an in-flight diagnostic. Once all in-flight diagnostics have ended,
/// they will either be emitted, or captured by an open transaction.
void endDiagnostic(const InFlightDiagnostic &D);

/// Called when tentative diagnostic is about to be flushed,
/// to apply any required transformations e.g. copy string arguments
/// to extend their lifetime.
void onTentativeDiagnosticFlush(Diagnostic &diagnostic);

/// Flush the active diagnostic.
void flushActiveDiagnostic();

/// Retrieve the active diagnostic.
Diagnostic &getActiveDiagnostic() { return *ActiveDiagnostic; }
/// Retrieve the stored active diagnostic for a given InFlightDiagnostic.
detail::ActiveDiagnostic &
getActiveDiagnostic(const InFlightDiagnostic &diag);

/// Generate DiagnosticInfo for a Diagnostic to be passed to consumers.
std::optional<DiagnosticInfo>
Expand All @@ -1162,7 +1185,7 @@ namespace swift {

/// Handle a new diagnostic, which will either be emitted, or added to an
/// active transaction.
void handleDiagnostic(Diagnostic &&diag);
void handleDiagnostic(detail::ActiveDiagnostic &&diag);

/// Clear any tentative diagnostics.
void clearTentativeDiagnostics();
Expand Down Expand Up @@ -1291,12 +1314,12 @@ namespace swift {
}

bool hasErrors() const {
ArrayRef<Diagnostic> diagnostics(Engine.TentativeDiagnostics.begin() +
PrevDiagnostics,
Engine.TentativeDiagnostics.end());
ArrayRef<detail::ActiveDiagnostic> diagnostics(
Engine.TentativeDiagnostics.begin() + PrevDiagnostics,
Engine.TentativeDiagnostics.end());

for (auto &diagnostic : diagnostics) {
auto behavior = Engine.state.determineBehavior(diagnostic);
auto behavior = Engine.state.determineBehavior(diagnostic.Diag);
if (behavior == DiagnosticBehavior::Fatal ||
behavior == DiagnosticBehavior::Error)
return true;
Expand Down Expand Up @@ -1361,14 +1384,14 @@ namespace swift {

// The first diagnostic is assumed to be the parent. If this is not an
// error or warning, we'll assert later when trying to add children.
Diagnostic &parent = Engine.TentativeDiagnostics[PrevDiagnostics];
Diagnostic &parent = Engine.TentativeDiagnostics[PrevDiagnostics].Diag;

// Associate the children with the parent.
for (auto diag =
Engine.TentativeDiagnostics.begin() + PrevDiagnostics + 1;
diag != Engine.TentativeDiagnostics.end(); ++diag) {
diag->setIsChildNote(true);
parent.addChildNote(std::move(*diag));
diag->Diag.setIsChildNote(true);
parent.addChildNote(std::move(diag->Diag));
}

// Erase the children, they'll be emitted alongside their parent.
Expand Down
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