Fix code that attempted to produce a diagnostic with one DiagnosticEngine, then

produce a note for that diagnostic either with a different DiagnosticEngine or
after calling DiagnosticEngine::Reset(). That didn't make any sense, and did the
wrong thing if the original diagnostic was suppressed.


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@170636 91177308-0d34-0410-b5e6-96231b3b80d8

3 files changed, 27 insertions, 10 deletions

diff --git a/lib/AST/ASTImporter.cpp b/lib/AST/ASTImporter.cpp
index f288953df6..33935c3b32 100644
--- a/lib/AST/ASTImporter.cpp
+++ b/lib/AST/ASTImporter.cpp
@@ -206,12 +206,16 @@ namespace {
     /// \brief Whether to complain about failures.
     bool Complain;
 
+    /// \brief \c true if the last diagnostic came from C2.
+    bool LastDiagFromC2;
+
     StructuralEquivalenceContext(ASTContext &C1, ASTContext &C2,
                llvm::DenseSet<std::pair<Decl *, Decl *> > &NonEquivalentDecls,
                                  bool StrictTypeSpelling = false,
                                  bool Complain = true)
       : C1(C1), C2(C2), NonEquivalentDecls(NonEquivalentDecls),
-        StrictTypeSpelling(StrictTypeSpelling), Complain(Complain) { }
+        StrictTypeSpelling(StrictTypeSpelling), Complain(Complain),
+        LastDiagFromC2(false) {}
 
     /// \brief Determine whether the two declarations are structurally
     /// equivalent.
@@ -229,11 +233,17 @@ namespace {
   public:
     DiagnosticBuilder Diag1(SourceLocation Loc, unsigned DiagID) {
       assert(Complain && "Not allowed to complain");
+      if (LastDiagFromC2)
+        C1.getDiagnostics().notePriorDiagnosticFrom(C2.getDiagnostics());
+      LastDiagFromC2 = false;
       return C1.getDiagnostics().Report(Loc, DiagID);
     }
 
     DiagnosticBuilder Diag2(SourceLocation Loc, unsigned DiagID) {
       assert(Complain && "Not allowed to complain");
+      if (!LastDiagFromC2)
+        C2.getDiagnostics().notePriorDiagnosticFrom(C1.getDiagnostics());
+      LastDiagFromC2 = true;
       return C2.getDiagnostics().Report(Loc, DiagID);
     }
   };
@@ -4319,7 +4329,7 @@ ASTImporter::ASTImporter(ASTContext &ToContext, FileManager &ToFileManager,
                          bool MinimalImport)
   : ToContext(ToContext), FromContext(FromContext),
     ToFileManager(ToFileManager), FromFileManager(FromFileManager),
-    Minimal(MinimalImport) 
+    Minimal(MinimalImport), LastDiagFromFrom(false)
 {
   ImportedDecls[FromContext.getTranslationUnitDecl()]
     = ToContext.getTranslationUnitDecl();
@@ -4822,10 +4832,18 @@ DeclarationName ASTImporter::HandleNameConflict(DeclarationName Name,
 }
 
 DiagnosticBuilder ASTImporter::ToDiag(SourceLocation Loc, unsigned DiagID) {
+  if (LastDiagFromFrom)
+    ToContext.getDiagnostics().notePriorDiagnosticFrom(
+      FromContext.getDiagnostics());
+  LastDiagFromFrom = false;
   return ToContext.getDiagnostics().Report(Loc, DiagID);
 }
 
 DiagnosticBuilder ASTImporter::FromDiag(SourceLocation Loc, unsigned DiagID) {
+  if (!LastDiagFromFrom)
+    FromContext.getDiagnostics().notePriorDiagnosticFrom(
+      ToContext.getDiagnostics());
+  LastDiagFromFrom = true;
   return FromContext.getDiagnostics().Report(Loc, DiagID);
 }
 
diff --git a/lib/Basic/Diagnostic.cpp b/lib/Basic/Diagnostic.cpp
index f5eec02138..70d3939150 100644
--- a/lib/Basic/Diagnostic.cpp
+++ b/lib/Basic/Diagnostic.cpp
@@ -108,11 +108,7 @@ void DiagnosticsEngine::Reset() {
   TrapNumUnrecoverableErrorsOccurred = 0;
   
   CurDiagID = ~0U;
-  // Set LastDiagLevel to an "unset" state. If we set it to 'Ignored', notes
-  // using a DiagnosticsEngine associated to a translation unit that follow
-  // diagnostics from a DiagnosticsEngine associated to anoter t.u. will not be
-  // displayed.
-  LastDiagLevel = (DiagnosticIDs::Level)-1;
+  LastDiagLevel = DiagnosticIDs::Ignored;
   DelayedDiagID = 0;
 
   // Clear state related to #pragma diagnostic.
diff --git a/lib/Driver/Driver.cpp b/lib/Driver/Driver.cpp
index d41bce5ba5..dcb3c5fd09 100644
--- a/lib/Driver/Driver.cpp
+++ b/lib/Driver/Driver.cpp
@@ -366,9 +366,12 @@ void Driver::generateCompilationDiagnostics(Compilation &C,
     C.PrintDiagnosticJob(OS, C.getJobs());
   OS.flush();
 
-  // Clear stale state and suppress tool output.
+  // Keep track of whether we produce any errors while trying to produce
+  // preprocessed sources.
+  DiagnosticErrorTrap Trap(Diags);
+
+  // Suppress tool output.
   C.initCompilationForDiagnostics();
-  Diags.Reset();
 
   // Construct the list of inputs.
   InputList Inputs;
@@ -430,7 +433,7 @@ void Driver::generateCompilationDiagnostics(Compilation &C,
   BuildJobs(C);
 
   // If there were errors building the compilation, quit now.
-  if (Diags.hasErrorOccurred()) {
+  if (Trap.hasErrorOccurred()) {
     Diag(clang::diag::note_drv_command_failed_diag_msg)
       << "Error generating preprocessed source(s).";
     return;