[clang][modules] Add support for merging lifetime-extended temporaries

Summary: Add support for merging lifetime-extended temporaries

Reviewers: rsmith

Reviewed By: rsmith

Subscribers: xbolva00, cfe-commits

Tags: #clang

Differential Revision: https://reviews.llvm.org/D70190

1 files changed, 22 insertions, 0 deletions

diff --git a/clang/lib/Serialization/ASTReaderDecl.cpp b/clang/lib/Serialization/ASTReaderDecl.cpp
index 8991a39a706..3f7a1ed7fd5 100644
--- a/clang/lib/Serialization/ASTReaderDecl.cpp
+++ b/clang/lib/Serialization/ASTReaderDecl.cpp
@@ -424,6 +424,8 @@ namespace clang {
     template<typename T>
     void mergeMergeable(Mergeable<T> *D);
 
+    void mergeMergeable(LifetimeExtendedTemporaryDecl *D);
+
     void mergeTemplatePattern(RedeclarableTemplateDecl *D,
                               RedeclarableTemplateDecl *Existing,
                               DeclID DsID, bool IsKeyDecl);
@@ -2358,6 +2360,7 @@ void ASTDeclReader::VisitLifetimeExtendedTemporaryDecl(
   if (Record.readInt())
     D->Value = new (D->getASTContext()) APValue(Record.readAPValue());
   D->ManglingNumber = Record.readInt();
+  mergeMergeable(D);
 }
 
 std::pair<uint64_t, uint64_t>
@@ -2555,6 +2558,25 @@ static bool allowODRLikeMergeInC(NamedDecl *ND) {
   return false;
 }
 
+/// Attempts to merge LifetimeExtendedTemporaryDecl with
+/// identical class definitions from two different modules.
+void ASTDeclReader::mergeMergeable(LifetimeExtendedTemporaryDecl *D) {
+  // If modules are not available, there is no reason to perform this merge.
+  if (!Reader.getContext().getLangOpts().Modules)
+    return;
+
+  LifetimeExtendedTemporaryDecl *LETDecl = D;
+
+  LifetimeExtendedTemporaryDecl *&LookupResult =
+      Reader.LETemporaryForMerging[std::make_pair(
+          LETDecl->getExtendingDecl(), LETDecl->getManglingNumber())];
+  if (LookupResult)
+    Reader.getContext().setPrimaryMergedDecl(LETDecl,
+                                             LookupResult->getCanonicalDecl());
+  else
+    LookupResult = LETDecl;
+}
+
 /// Attempts to merge the given declaration (D) with another declaration
 /// of the same entity, for the case where the entity is not actually
 /// redeclarable. This happens, for instance, when merging the fields of