1 files changed, 55 insertions, 8 deletions

diff --git a/clang/lib/Serialization/ASTReader.cpp b/clang/lib/Serialization/ASTReader.cpp
index 3125b8e43e9..7774b7b1c6e 100644
--- a/clang/lib/Serialization/ASTReader.cpp
+++ b/clang/lib/Serialization/ASTReader.cpp
@@ -108,9 +108,12 @@ ChainedASTReaderListener::ReadFileSystemOptions(const FileSystemOptions &FSOpts,
 }
 
 bool ChainedASTReaderListener::ReadHeaderSearchOptions(
-    const HeaderSearchOptions &HSOpts, bool Complain) {
-  return First->ReadHeaderSearchOptions(HSOpts, Complain) ||
-         Second->ReadHeaderSearchOptions(HSOpts, Complain);
+    const HeaderSearchOptions &HSOpts, StringRef SpecificModuleCachePath,
+    bool Complain) {
+  return First->ReadHeaderSearchOptions(HSOpts, SpecificModuleCachePath,
+                                        Complain) ||
+         Second->ReadHeaderSearchOptions(HSOpts, SpecificModuleCachePath,
+                                         Complain);
 }
 bool ChainedASTReaderListener::ReadPreprocessorOptions(
     const PreprocessorOptions &PPOpts, bool Complain,
@@ -464,7 +467,7 @@ collectMacroDefinitions(const PreprocessorOptions &PPOpts,
     Macros[MacroName] = std::make_pair(MacroBody, false);
   }
 }
-         
+
 /// \brief Check the preprocessor options deserialized from the control block
 /// against the preprocessor options in an existing preprocessor.
 ///
@@ -591,6 +594,36 @@ bool PCHValidator::ReadPreprocessorOptions(const PreprocessorOptions &PPOpts,
                                   PP.getLangOpts());
 }
 
+/// Check the header search options deserialized from the control block
+/// against the header search options in an existing preprocessor.
+///
+/// \param Diags If non-null, produce diagnostics for any mismatches incurred.
+static bool checkHeaderSearchOptions(const HeaderSearchOptions &HSOpts,
+                                     StringRef SpecificModuleCachePath,
+                                     StringRef ExistingModuleCachePath,
+                                     DiagnosticsEngine *Diags,
+                                     const LangOptions &LangOpts) {
+  if (LangOpts.Modules) {
+    if (SpecificModuleCachePath != ExistingModuleCachePath) {
+      if (Diags)
+        Diags->Report(diag::err_pch_modulecache_mismatch)
+          << SpecificModuleCachePath << ExistingModuleCachePath;
+      return true;
+    }
+  }
+
+  return false;
+}
+
+bool PCHValidator::ReadHeaderSearchOptions(const HeaderSearchOptions &HSOpts,
+                                           StringRef SpecificModuleCachePath,
+                                           bool Complain) {
+  return checkHeaderSearchOptions(HSOpts, SpecificModuleCachePath,
+                                  PP.getHeaderSearchInfo().getModuleCachePath(),
+                                  Complain ? &Reader.Diags : nullptr,
+                                  PP.getLangOpts());
+}
+
 void PCHValidator::ReadCounter(const ModuleFile &M, unsigned Value) {
   PP.setCounterValue(Value);
 }
@@ -4191,16 +4224,19 @@ namespace {
     const LangOptions &ExistingLangOpts;
     const TargetOptions &ExistingTargetOpts;
     const PreprocessorOptions &ExistingPPOpts;
+    std::string ExistingModuleCachePath;
     FileManager &FileMgr;
-    
+
   public:
     SimplePCHValidator(const LangOptions &ExistingLangOpts,
                        const TargetOptions &ExistingTargetOpts,
                        const PreprocessorOptions &ExistingPPOpts,
+                       StringRef ExistingModuleCachePath,
                        FileManager &FileMgr)
       : ExistingLangOpts(ExistingLangOpts),
         ExistingTargetOpts(ExistingTargetOpts),
         ExistingPPOpts(ExistingPPOpts),
+        ExistingModuleCachePath(ExistingModuleCachePath),
         FileMgr(FileMgr)
     {
     }
@@ -4214,6 +4250,13 @@ namespace {
                            bool Complain) override {
       return checkTargetOptions(ExistingTargetOpts, TargetOpts, nullptr);
     }
+    bool ReadHeaderSearchOptions(const HeaderSearchOptions &HSOpts,
+                                 StringRef SpecificModuleCachePath,
+                                 bool Complain) override {
+      return checkHeaderSearchOptions(HSOpts, SpecificModuleCachePath,
+                                      ExistingModuleCachePath,
+                                      nullptr, ExistingLangOpts);
+    }
     bool ReadPreprocessorOptions(const PreprocessorOptions &PPOpts,
                                  bool Complain,
                                  std::string &SuggestedPredefines) override {
@@ -4408,8 +4451,10 @@ bool ASTReader::isAcceptableASTFile(StringRef Filename,
                                     FileManager &FileMgr,
                                     const LangOptions &LangOpts,
                                     const TargetOptions &TargetOpts,
-                                    const PreprocessorOptions &PPOpts) {
-  SimplePCHValidator validator(LangOpts, TargetOpts, PPOpts, FileMgr);
+                                    const PreprocessorOptions &PPOpts,
+                                    std::string ExistingModuleCachePath) {
+  SimplePCHValidator validator(LangOpts, TargetOpts, PPOpts,
+                               ExistingModuleCachePath, FileMgr);
   return !readASTFileControlBlock(Filename, FileMgr, validator);
 }
 
@@ -4780,8 +4825,10 @@ bool ASTReader::ParseHeaderSearchOptions(const RecordData &Record,
   HSOpts.UseStandardSystemIncludes = Record[Idx++];
   HSOpts.UseStandardCXXIncludes = Record[Idx++];
   HSOpts.UseLibcxx = Record[Idx++];
+  std::string SpecificModuleCachePath = ReadString(Record, Idx);
 
-  return Listener.ReadHeaderSearchOptions(HSOpts, Complain);
+  return Listener.ReadHeaderSearchOptions(HSOpts, SpecificModuleCachePath,
+                                          Complain);
 }
 
 bool ASTReader::ParsePreprocessorOptions(const RecordData &Record,