9 files changed, 25 insertions, 17 deletions
diff --git a/clang/include/clang/Sema/ExternalSemaSource.h b/clang/include/clang/Sema/ExternalSemaSource.h
index 1083784fb7f..430cef7846b 100644
--- a/clang/include/clang/Sema/ExternalSemaSource.h
+++ b/clang/include/clang/Sema/ExternalSemaSource.h
@@ -182,7 +182,7 @@ public:
   /// external source should take care not to introduce the same map entries
   /// repeatedly.
   virtual void ReadLateParsedTemplates(
-      llvm::DenseMap<const FunctionDecl *, LateParsedTemplate *> &LPTMap) {}
+      llvm::MapVector<const FunctionDecl *, LateParsedTemplate *> &LPTMap) {}
 
   /// \copydoc Sema::CorrectTypo
   /// \note LookupKind must correspond to a valid Sema::LookupNameKind
diff --git a/clang/include/clang/Sema/MultiplexExternalSemaSource.h b/clang/include/clang/Sema/MultiplexExternalSemaSource.h
index 7a57abc0106..5f717891032 100644
--- a/clang/include/clang/Sema/MultiplexExternalSemaSource.h
+++ b/clang/include/clang/Sema/MultiplexExternalSemaSource.h
@@ -331,8 +331,8 @@ public:
   /// external source should take care not to introduce the same map entries
   /// repeatedly.
   void ReadLateParsedTemplates(
-                         llvm::DenseMap<const FunctionDecl *,
-                                        LateParsedTemplate *> &LPTMap) override;
+      llvm::MapVector<const FunctionDecl *, LateParsedTemplate *> &LPTMap)
+      override;
 
   /// \copydoc ExternalSemaSource::CorrectTypo
   /// \note Returns the first nonempty correction.
diff --git a/clang/include/clang/Sema/Sema.h b/clang/include/clang/Sema/Sema.h
index dde928ff914..21fe2e493c2 100644
--- a/clang/include/clang/Sema/Sema.h
+++ b/clang/include/clang/Sema/Sema.h
@@ -455,8 +455,8 @@ public:
   SmallVector<std::pair<CXXMethodDecl*, const FunctionProtoType*>, 2>
     DelayedDefaultedMemberExceptionSpecs;
 
-  typedef llvm::DenseMap<const FunctionDecl *, LateParsedTemplate *>
-  LateParsedTemplateMapT;
+  typedef llvm::MapVector<const FunctionDecl *, LateParsedTemplate *>
+      LateParsedTemplateMapT;
   LateParsedTemplateMapT LateParsedTemplateMap;
 
   /// \brief Callback to the parser to parse templated functions when needed.
diff --git a/clang/include/clang/Serialization/ASTReader.h b/clang/include/clang/Serialization/ASTReader.h
index 1471910db47..f8366f7621a 100644
--- a/clang/include/clang/Serialization/ASTReader.h
+++ b/clang/include/clang/Serialization/ASTReader.h
@@ -1832,8 +1832,8 @@ public:
                                            SourceLocation> > &Pending) override;
 
   void ReadLateParsedTemplates(
-                         llvm::DenseMap<const FunctionDecl *,
-                                        LateParsedTemplate *> &LPTMap) override;
+      llvm::MapVector<const FunctionDecl *, LateParsedTemplate *> &LPTMap)
+      override;
 
   /// \brief Load a selector from disk, registering its ID if it exists.
   void LoadSelector(Selector Sel);
diff --git a/clang/lib/Sema/MultiplexExternalSemaSource.cpp b/clang/lib/Sema/MultiplexExternalSemaSource.cpp
index bd7e785780b..51a12746fdd 100644
--- a/clang/lib/Sema/MultiplexExternalSemaSource.cpp
+++ b/clang/lib/Sema/MultiplexExternalSemaSource.cpp
@@ -276,7 +276,7 @@ void MultiplexExternalSemaSource::ReadPendingInstantiations(
 }
 
 void MultiplexExternalSemaSource::ReadLateParsedTemplates(
-    llvm::DenseMap<const FunctionDecl *, LateParsedTemplate *> &LPTMap) {
+    llvm::MapVector<const FunctionDecl *, LateParsedTemplate *> &LPTMap) {
   for (size_t i = 0; i < Sources.size(); ++i)
     Sources[i]->ReadLateParsedTemplates(LPTMap);
 }
diff --git a/clang/lib/Sema/SemaTemplate.cpp b/clang/lib/Sema/SemaTemplate.cpp
index fad15bbc4f6..805709dab80 100644
--- a/clang/lib/Sema/SemaTemplate.cpp
+++ b/clang/lib/Sema/SemaTemplate.cpp
@@ -8305,7 +8305,7 @@ void Sema::MarkAsLateParsedTemplate(FunctionDecl *FD, Decl *FnD,
   // Take tokens to avoid allocations
   LPT->Toks.swap(Toks);
   LPT->D = FnD;
-  LateParsedTemplateMap[FD] = LPT;
+  LateParsedTemplateMap.insert(std::make_pair(FD, LPT));
 
   FD->setLateTemplateParsed(true);
 }
diff --git a/clang/lib/Serialization/ASTReader.cpp b/clang/lib/Serialization/ASTReader.cpp
index 2273979883a..4d5141bf921 100644
--- a/clang/lib/Serialization/ASTReader.cpp
+++ b/clang/lib/Serialization/ASTReader.cpp
@@ -7453,7 +7453,7 @@ void ASTReader::ReadPendingInstantiations(
 }
 
 void ASTReader::ReadLateParsedTemplates(
-    llvm::DenseMap<const FunctionDecl *, LateParsedTemplate *> &LPTMap) {
+    llvm::MapVector<const FunctionDecl *, LateParsedTemplate *> &LPTMap) {
   for (unsigned Idx = 0, N = LateParsedTemplates.size(); Idx < N;
        /* In loop */) {
     FunctionDecl *FD = cast<FunctionDecl>(GetDecl(LateParsedTemplates[Idx++]));
@@ -7469,7 +7469,7 @@ void ASTReader::ReadLateParsedTemplates(
     for (unsigned T = 0; T < TokN; ++T)
       LT->Toks.push_back(ReadToken(*F, LateParsedTemplates, Idx));
 
-    LPTMap[FD] = LT;
+    LPTMap.insert(std::make_pair(FD, LT));
   }
 
   LateParsedTemplates.clear();
diff --git a/clang/lib/Serialization/ASTWriter.cpp b/clang/lib/Serialization/ASTWriter.cpp
index 7227a97e7b9..679419c9c5a 100644
--- a/clang/lib/Serialization/ASTWriter.cpp
+++ b/clang/lib/Serialization/ASTWriter.cpp
@@ -4089,11 +4089,10 @@ void ASTWriter::WriteLateParsedTemplates(Sema &SemaRef) {
     return;
 
   RecordData Record;
-  for (Sema::LateParsedTemplateMapT::iterator It = LPTMap.begin(),
-                                              ItEnd = LPTMap.end();
-       It != ItEnd; ++It) {
-    LateParsedTemplate *LPT = It->second;
-    AddDeclRef(It->first, Record);
+  for (auto LPTMapEntry : LPTMap) {
+    const FunctionDecl *FD = LPTMapEntry.first;
+    LateParsedTemplate *LPT = LPTMapEntry.second;
+    AddDeclRef(FD, Record);
     AddDeclRef(LPT->D, Record);
     Record.push_back(LPT->Toks.size());
 
diff --git a/clang/test/Modules/stress1.cpp b/clang/test/Modules/stress1.cpp
index e03e538a3ce..df690aa7e65 100644
--- a/clang/test/Modules/stress1.cpp
+++ b/clang/test/Modules/stress1.cpp
@@ -17,13 +17,22 @@
 //
 // RUN: diff %t/m00.pcm %t/m00_check.pcm
 //
-// RUN: %clang_cc1 -fmodules -x c++ -std=c++11 \
+// RUN: %clang_cc1 -fmodules -x c++ -std=c++11 -fdelayed-template-parsing \
 // RUN:   -I Inputs/stress1 \
 // RUN:   -fno-implicit-modules -fno-modules-implicit-maps \
 // RUN:   -fmodule-map-file-home-is-cwd \
 // RUN:   -emit-module -fmodule-name=m01 -o %t/m01.pcm \
 // RUN:   Inputs/stress1/module.modulemap
 //
+// RUN: %clang_cc1 -fmodules -x c++ -std=c++11 -fdelayed-template-parsing \
+// RUN:   -I Inputs/stress1 \
+// RUN:   -fno-implicit-modules -fno-modules-implicit-maps \
+// RUN:   -fmodule-map-file-home-is-cwd \
+// RUN:   -emit-module -fmodule-name=m01 -o %t/m01_check.pcm \
+// RUN:   Inputs/stress1/module.modulemap
+//
+// RUN: diff %t/m01.pcm %t/m01_check.pcm
+//
 // RUN: %clang_cc1 -fmodules -x c++ -std=c++11 \
 // RUN:   -I Inputs/stress1 \
 // RUN:   -fno-implicit-modules -fno-modules-implicit-maps \