1 files changed, 123 insertions, 8 deletions

diff --git a/clang/lib/Serialization/ASTReader.cpp b/clang/lib/Serialization/ASTReader.cpp
index 834917de1d4..c6aec4592ba 100644
--- a/clang/lib/Serialization/ASTReader.cpp
+++ b/clang/lib/Serialization/ASTReader.cpp
@@ -29,6 +29,7 @@
 #include "clang/Basic/TargetOptions.h"
 #include "clang/Basic/Version.h"
 #include "clang/Basic/VersionTuple.h"
+#include "clang/Frontend/Utils.h"
 #include "clang/Lex/HeaderSearch.h"
 #include "clang/Lex/HeaderSearchOptions.h"
 #include "clang/Lex/MacroInfo.h"
@@ -90,7 +91,7 @@ ChainedASTReaderListener::ReadTargetOptions(const TargetOptions &TargetOpts,
          Second->ReadTargetOptions(TargetOpts, Complain);
 }
 bool ChainedASTReaderListener::ReadDiagnosticOptions(
-    const DiagnosticOptions &DiagOpts, bool Complain) {
+    IntrusiveRefCntPtr<DiagnosticOptions> DiagOpts, bool Complain) {
   return First->ReadDiagnosticOptions(DiagOpts, Complain) ||
          Second->ReadDiagnosticOptions(DiagOpts, Complain);
 }
@@ -291,6 +292,120 @@ namespace {
     DeclsMap;
 }
 
+static bool checkDiagnosticGroupMappings(DiagnosticsEngine &StoredDiags,
+                                         DiagnosticsEngine &Diags,
+                                         bool Complain) {
+  typedef DiagnosticsEngine::Level Level;
+
+  // Check current mappings for new -Werror mappings, and the stored mappings
+  // for cases that were explicitly mapped to *not* be errors that are now
+  // errors because of options like -Werror.
+  DiagnosticsEngine *MappingSources[] = { &Diags, &StoredDiags };
+
+  for (DiagnosticsEngine *MappingSource : MappingSources) {
+    for (auto DiagIDMappingPair : MappingSource->getDiagnosticMappings()) {
+      diag::kind DiagID = DiagIDMappingPair.first;
+      Level CurLevel = Diags.getDiagnosticLevel(DiagID, SourceLocation());
+      if (CurLevel < DiagnosticsEngine::Error)
+        continue; // not significant
+      Level StoredLevel =
+          StoredDiags.getDiagnosticLevel(DiagID, SourceLocation());
+      if (StoredLevel < DiagnosticsEngine::Error) {
+        if (Complain)
+          Diags.Report(diag::err_pch_diagopt_mismatch) << "-Werror=" +
+              Diags.getDiagnosticIDs()->getWarningOptionForDiag(DiagID).str();
+        return true;
+      }
+    }
+  }
+
+  return false;
+}
+
+static DiagnosticsEngine::ExtensionHandling
+isExtHandlingFromDiagsError(DiagnosticsEngine &Diags) {
+  DiagnosticsEngine::ExtensionHandling Ext =
+      Diags.getExtensionHandlingBehavior();
+  if (Ext == DiagnosticsEngine::Ext_Warn && Diags.getWarningsAsErrors())
+    Ext = DiagnosticsEngine::Ext_Error;
+  return Ext;
+}
+
+static bool checkDiagnosticMappings(DiagnosticsEngine &StoredDiags,
+                                    DiagnosticsEngine &Diags,
+                                    bool IsSystem, bool Complain) {
+  // Top-level options
+  if (IsSystem) {
+    if (Diags.getSuppressSystemWarnings())
+      return false;
+    // If -Wsystem-headers was not enabled before, be conservative
+    if (StoredDiags.getSuppressSystemWarnings()) {
+      if (Complain)
+        Diags.Report(diag::err_pch_diagopt_mismatch) << "-Wsystem-headers";
+      return true;
+    }
+  }
+
+  if (Diags.getWarningsAsErrors() && !StoredDiags.getWarningsAsErrors()) {
+    if (Complain)
+      Diags.Report(diag::err_pch_diagopt_mismatch) << "-Werror";
+    return true;
+  }
+
+  if (Diags.getWarningsAsErrors() && Diags.getEnableAllWarnings() &&
+      !StoredDiags.getEnableAllWarnings()) {
+    if (Complain)
+      Diags.Report(diag::err_pch_diagopt_mismatch) << "-Weverything -Werror";
+    return true;
+  }
+
+  if (isExtHandlingFromDiagsError(Diags) &&
+      !isExtHandlingFromDiagsError(StoredDiags)) {
+    if (Complain)
+      Diags.Report(diag::err_pch_diagopt_mismatch) << "-pedantic-errors";
+    return true;
+  }
+
+  return checkDiagnosticGroupMappings(StoredDiags, Diags, Complain);
+}
+
+bool PCHValidator::ReadDiagnosticOptions(
+    IntrusiveRefCntPtr<DiagnosticOptions> DiagOpts, bool Complain) {
+  DiagnosticsEngine &ExistingDiags = PP.getDiagnostics();
+  IntrusiveRefCntPtr<DiagnosticIDs> DiagIDs(ExistingDiags.getDiagnosticIDs());
+  IntrusiveRefCntPtr<DiagnosticsEngine> Diags(
+      new DiagnosticsEngine(DiagIDs, DiagOpts.getPtr()));
+  // This should never fail, because we would have processed these options
+  // before writing them to an ASTFile.
+  ProcessWarningOptions(*Diags, *DiagOpts, /*Report*/false);
+
+  ModuleManager &ModuleMgr = Reader.getModuleManager();
+  assert(ModuleMgr.size() >= 1 && "what ASTFile is this then");
+
+  // If the original import came from a file explicitly generated by the user,
+  // don't check the diagnostic mappings.
+  // FIXME: currently this is approximated by checking whether this is not a
+  // module import.
+  // Note: ModuleMgr.rbegin() may not be the current module, but it must be in
+  // the transitive closure of its imports, since unrelated modules cannot be
+  // imported until after this module finishes validation.
+  ModuleFile *TopImport = *ModuleMgr.rbegin();
+  while (!TopImport->ImportedBy.empty())
+    TopImport = TopImport->ImportedBy[0];
+  if (TopImport->Kind != MK_Module)
+    return false;
+
+  StringRef ModuleName = TopImport->ModuleName;
+  assert(!ModuleName.empty() && "diagnostic options read before module name");
+
+  Module *M = PP.getHeaderSearchInfo().lookupModule(ModuleName);
+  assert(M && "missing module");
+
+  // FIXME: if the diagnostics are incompatible, save a DiagnosticOptions that
+  // contains the union of their flags.
+  return checkDiagnosticMappings(*Diags, ExistingDiags, M->IsSystem, Complain);
+}
+
 /// \brief Collect the macro definitions provided by the given preprocessor
 /// options.
 static void collectMacroDefinitions(const PreprocessorOptions &PPOpts,
@@ -2268,11 +2383,11 @@ ASTReader::ReadControlBlock(ModuleFile &F,
     }
 
     case DIAGNOSTIC_OPTIONS: {
-      bool Complain = (ClientLoadCapabilities & ARR_ConfigurationMismatch)==0;
+      bool Complain = (ClientLoadCapabilities & ARR_OutOfDate)==0;
       if (Listener && &F == *ModuleMgr.begin() &&
           ParseDiagnosticOptions(Record, Complain, *Listener) &&
-          !DisableValidation && !AllowConfigurationMismatch)
-        return ConfigurationMismatch;
+          !DisableValidation)
+        return OutOfDate;
       break;
     }
 
@@ -4481,15 +4596,15 @@ bool ASTReader::ParseTargetOptions(const RecordData &Record,
 
 bool ASTReader::ParseDiagnosticOptions(const RecordData &Record, bool Complain,
                                        ASTReaderListener &Listener) {
-  DiagnosticOptions DiagOpts;
+  IntrusiveRefCntPtr<DiagnosticOptions> DiagOpts(new DiagnosticOptions);
   unsigned Idx = 0;
-#define DIAGOPT(Name, Bits, Default) DiagOpts.Name = Record[Idx++];
+#define DIAGOPT(Name, Bits, Default) DiagOpts->Name = Record[Idx++];
 #define ENUM_DIAGOPT(Name, Type, Bits, Default) \
-  DiagOpts.set##Name(static_cast<Type>(Record[Idx++]));
+  DiagOpts->set##Name(static_cast<Type>(Record[Idx++]));
 #include "clang/Basic/DiagnosticOptions.def"
 
   for (unsigned N = Record[Idx++]; N; --N) {
-    DiagOpts.Warnings.push_back(ReadString(Record, Idx));
+    DiagOpts->Warnings.push_back(ReadString(Record, Idx));
   }
 
   return Listener.ReadDiagnosticOptions(DiagOpts, Complain);