Fix analysis based warnings so that all warnings are emitted when compiling

with -Werror.  Previously, compiling with -Werror would emit only the first
warning in a compilation unit, because clang assumes that once an error occurs,
further analysis is unlikely to return valid results.  However, warnings that
have been upgraded to errors should not be treated as "errors" in this sense.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@169649 91177308-0d34-0410-b5e6-96231b3b80d8

include/clang/Basic/Diagnostic.h

@@ -279,6 +279,10 @@ private:
   /// \brief Sticky flag set to \c true when an error is emitted.
   bool ErrorOccurred;
 
+  /// \brief Sticky flag set to \c true when an "uncompilable error" occurs.
+  /// I.e. an error that was not upgraded from a warning by -Werror.
+  bool UncompilableErrorOccurred;
+
   /// \brief Sticky flag set to \c true when a fatal error is emitted.
   bool FatalErrorOccurred;
 
@@ -558,6 +562,12 @@ public:
                                   SourceLocation Loc = SourceLocation());
 
   bool hasErrorOccurred() const { return ErrorOccurred; }
+
+  /// \brief Errors that actually prevent compilation, not those that are
+  /// upgraded from a warning by -Werror.
+  bool hasUncompilableErrorOccurred() const {
+    return UncompilableErrorOccurred;
+  }
   bool hasFatalErrorOccurred() const { return FatalErrorOccurred; }
   
   /// \brief Determine whether any kind of unrecoverable error has occurred.

lib/Basic/Diagnostic.cpp

@@ -97,6 +97,7 @@ bool DiagnosticsEngine::popMappings(SourceLocation Loc) {
 
 void DiagnosticsEngine::Reset() {
   ErrorOccurred = false;
+  UncompilableErrorOccurred = false;
   FatalErrorOccurred = false;
   UnrecoverableErrorOccurred = false;
   

lib/Basic/DiagnosticIDs.cpp

@@ -628,6 +628,10 @@ bool DiagnosticIDs::ProcessDiag(DiagnosticsEngine &Diag) const {
     if (isUnrecoverable(DiagID))
       Diag.UnrecoverableErrorOccurred = true;
 
+    // Warnings which have been upgraded to errors do not prevent compilation.
+    if (isDefaultMappingAsError(DiagID))
+      Diag.UncompilableErrorOccurred = true;
+
     Diag.ErrorOccurred = true;
     if (Diag.Client->IncludeInDiagnosticCounts()) {
       ++Diag.NumErrors;

lib/Sema/AnalysisBasedWarnings.cpp

@@ -1423,7 +1423,7 @@ AnalysisBasedWarnings::IssueWarnings(sema::AnalysisBasedWarnings::Policy P,
   if (cast<DeclContext>(D)->isDependentContext())
     return;
 
-  if (Diags.hasErrorOccurred() || Diags.hasFatalErrorOccurred()) {
+  if (Diags.hasUncompilableErrorOccurred() || Diags.hasFatalErrorOccurred()) {
     // Flush out any possibly unreachable diagnostics.
     flushDiagnostics(S, fscope);
     return;

lib/Sema/SemaDecl.cpp

@@ -8125,7 +8125,9 @@ Decl *Sema::ActOnFinishFunctionBody(Decl *dcl, Stmt *Body,
     if (PP.getDiagnostics().hasErrorOccurred() ||
         PP.getDiagnostics().getSuppressAllDiagnostics()) {
       DiscardCleanupsInEvaluationContext();
-    } else if (!isa<FunctionTemplateDecl>(dcl)) {
+    }
+    if (!PP.getDiagnostics().hasUncompilableErrorOccurred() &&
+        !isa<FunctionTemplateDecl>(dcl)) {
       // Since the body is valid, issue any analysis-based warnings that are
       // enabled.
       ActivePolicy = &WP;