Support tentative definitions in precompiled headers. This isn't likely

to happen (ever), but at least we'll do the right thing when it does.


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@69829 91177308-0d34-0410-b5e6-96231b3b80d8

2 files changed, 28 insertions, 0 deletions

diff --git a/lib/Frontend/PCHReader.cpp b/lib/Frontend/PCHReader.cpp
index 6de13045bb..28cca4d0ff 100644
--- a/lib/Frontend/PCHReader.cpp
+++ b/lib/Frontend/PCHReader.cpp
@@ -1713,6 +1713,13 @@ PCHReader::ReadPCHBlock(uint64_t &PreprocessorBlockOffset) {
       TotalNumMacros = Record[1];
       break;
 
+    case pch::TENTATIVE_DEFINITIONS:
+      if (!TentativeDefinitions.empty()) {
+        Error("Duplicate TENTATIVE_DEFINITIONS record in PCH file");
+        return Failure;
+      }
+      TentativeDefinitions.swap(Record);
+      break;
     }
   }
 
@@ -2523,6 +2530,13 @@ void PCHReader::InitializeSema(Sema &S) {
     SemaObj->IdResolver.AddDecl(PreloadedDecls[I]);
   }
   PreloadedDecls.clear();
+
+  // If there were any tentative definitions, deserialize them and add
+  // them to Sema's table of tentative definitions.
+  for (unsigned I = 0, N = TentativeDefinitions.size(); I != N; ++I) {
+    VarDecl *Var = cast<VarDecl>(GetDecl(TentativeDefinitions[I]));
+    SemaObj->TentativeDefinitions[Var->getDeclName()] = Var;
+  }
 }
 
 IdentifierInfo* PCHReader::get(const char *NameStart, const char *NameEnd) {
diff --git a/lib/Frontend/PCHWriter.cpp b/lib/Frontend/PCHWriter.cpp
index b081a2813f..097ced2363 100644
--- a/lib/Frontend/PCHWriter.cpp
+++ b/lib/Frontend/PCHWriter.cpp
@@ -2024,6 +2024,15 @@ void PCHWriter::WritePCH(Sema &SemaRef) {
       getIdentifierRef(&Table.get(BuiltinNames[I]));
   }
 
+  // Build a record containing all of the tentative definitions in
+  // this header file. Generally, this record will be empty.
+  RecordData TentativeDefinitions;
+  for (llvm::DenseMap<DeclarationName, VarDecl *>::iterator 
+         TD = SemaRef.TentativeDefinitions.begin(),
+         TDEnd = SemaRef.TentativeDefinitions.end();
+       TD != TDEnd; ++TD)
+    AddDeclRef(TD->second, TentativeDefinitions);
+
   // Write the remaining PCH contents.
   RecordData Record;
   Stream.EnterSubblock(pch::PCH_BLOCK_ID, 3);
@@ -2042,8 +2051,13 @@ void PCHWriter::WritePCH(Sema &SemaRef) {
   AddTypeRef(Context.getBuiltinVaListType(), Record);
   Stream.EmitRecord(pch::SPECIAL_TYPES, Record);
 
+  // Write the record containing external, unnamed definitions.
   if (!ExternalDefinitions.empty())
     Stream.EmitRecord(pch::EXTERNAL_DEFINITIONS, ExternalDefinitions);
+
+  // Write the record containing tentative definitions.
+  if (!TentativeDefinitions.empty())
+    Stream.EmitRecord(pch::TENTATIVE_DEFINITIONS, TentativeDefinitions);
   
   // Some simple statistics
   Record.clear();