1 files changed, 20 insertions, 11 deletions
diff --git a/lib/Basic/DiagnosticIDs.cpp b/lib/Basic/DiagnosticIDs.cpp
index 8f2c3d06a5..e8a99d08a9 100644
--- a/lib/Basic/DiagnosticIDs.cpp
+++ b/lib/Basic/DiagnosticIDs.cpp
@@ -1,9 +1,8 @@
 //===--- DiagnosticIDs.cpp - Diagnostic IDs Handling ----------------------===//
 //
-//                     The LLVM Compiler Infrastructure
-//
-// This file is distributed under the University of Illinois Open Source
-// License. See LICENSE.TXT for details.
+// 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
 //
 //===----------------------------------------------------------------------===//
 //
@@ -457,12 +456,17 @@ DiagnosticIDs::getDiagnosticSeverity(unsigned DiagID, SourceLocation Loc,
   if (Result == diag::Severity::Ignored)
     return Result;
 
-  // Honor -w, which is lower in priority than pedantic-errors, but higher than
-  // -Werror.
-  // FIXME: Under GCC, this also suppresses warnings that have been mapped to
-  // errors by -W flags and #pragma diagnostic.
-  if (Result == diag::Severity::Warning && State->IgnoreAllWarnings)
-    return diag::Severity::Ignored;
+  // Honor -w: this disables all messages which which are not Error/Fatal by
+  // default (disregarding attempts to upgrade severity from Warning to Error),
+  // as well as disabling all messages which are currently mapped to Warning
+  // (whether by default or downgraded from Error via e.g. -Wno-error or #pragma
+  // diagnostic.)
+  if (State->IgnoreAllWarnings) {
+    if (Result == diag::Severity::Warning ||
+        (Result >= diag::Severity::Error &&
+         !isDefaultMappingAsError((diag::kind)DiagID)))
+      return diag::Severity::Ignored;
+  }
 
   // If -Werror is enabled, map warnings to errors unless explicitly disabled.
   if (Result == diag::Severity::Warning) {
@@ -477,6 +481,11 @@ DiagnosticIDs::getDiagnosticSeverity(unsigned DiagID, SourceLocation Loc,
       Result = diag::Severity::Fatal;
   }
 
+  // If explicitly requested, map fatal errors to errors.
+  if (Result == diag::Severity::Fatal &&
+      Diag.CurDiagID != diag::fatal_too_many_errors && Diag.FatalsAsError)
+    Result = diag::Severity::Error;
+
   // Custom diagnostics always are emitted in system headers.
   bool ShowInSystemHeader =
       !GetDiagInfo(DiagID) || GetDiagInfo(DiagID)->WarnShowInSystemHeader;
@@ -656,7 +665,7 @@ bool DiagnosticIDs::ProcessDiag(DiagnosticsEngine &Diag) const {
 
   // If a fatal error has already been emitted, silence all subsequent
   // diagnostics.
-  if (Diag.FatalErrorOccurred && Diag.SuppressAfterFatalError) {
+  if (Diag.FatalErrorOccurred) {
     if (DiagLevel >= DiagnosticIDs::Error &&
         Diag.Client->IncludeInDiagnosticCounts()) {
       ++Diag.NumErrors;