[Basic] Add a DiagnosticError llvm::ErrorInfo subclass

Clang's DiagnosticError is an llvm::Error payload that stores a partial
diagnostic and its location. I'll be using it in the refactoring engine.

Differential Revision: https://reviews.llvm.org/D36969


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@311778 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 61 insertions, 0 deletions

diff --git a/include/clang/Basic/DiagnosticError.h b/include/clang/Basic/DiagnosticError.h
new file mode 100644
index 0000000000..6b4b073736
--- /dev/null
+++ b/include/clang/Basic/DiagnosticError.h
@@ -0,0 +1,61 @@
+//===--- DiagnosticError.h - Diagnostic payload for llvm::Error -*- C++ -*-===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_CLANG_BASIC_DIAGNOSTIC_ERROR_H
+#define LLVM_CLANG_BASIC_DIAGNOSTIC_ERROR_H
+
+#include "clang/Basic/PartialDiagnostic.h"
+#include "llvm/Support/Error.h"
+
+namespace clang {
+
+/// \brief Carries a Clang diagnostic in an llvm::Error.
+///
+/// Users should emit the stored diagnostic using the DiagnosticsEngine.
+class DiagnosticError : public llvm::ErrorInfo<DiagnosticError> {
+public:
+  DiagnosticError(PartialDiagnosticAt Diag) : Diag(std::move(Diag)) {}
+
+  void log(raw_ostream &OS) const override { OS << "clang diagnostic"; }
+
+  PartialDiagnosticAt &getDiagnostic() { return Diag; }
+  const PartialDiagnosticAt &getDiagnostic() const { return Diag; }
+
+  /// Creates a new \c DiagnosticError that contains the given diagnostic at
+  /// the given location.
+  static llvm::Error create(SourceLocation Loc, PartialDiagnostic Diag) {
+    return llvm::make_error<DiagnosticError>(
+        PartialDiagnosticAt(Loc, std::move(Diag)));
+  }
+
+  /// Extracts and returns the diagnostic payload from the given \c Error if
+  /// the error is a \c DiagnosticError. Returns none if the given error is not
+  /// a \c DiagnosticError.
+  static Optional<PartialDiagnosticAt> take(llvm::Error &Err) {
+    Optional<PartialDiagnosticAt> Result;
+    Err = llvm::handleErrors(std::move(Err), [&](DiagnosticError &E) {
+      Result = std::move(E.getDiagnostic());
+    });
+    return Result;
+  }
+
+  static char ID;
+
+private:
+  // Users are not expected to use error_code.
+  std::error_code convertToErrorCode() const override {
+    return llvm::inconvertibleErrorCode();
+  }
+
+  PartialDiagnosticAt Diag;
+};
+
+} // end namespace clang
+
+#endif // LLVM_CLANG_BASIC_DIAGNOSTIC_ERROR_H