[NFC] Move DeclID from serialization/ASTBitCodes.h to AST/DeclID.h (#89873)

Previously, the DeclID is defined in serialization/ASTBitCodes.h under
clang::serialization namespace. However, actually the DeclID is not
purely used in serialization part. The DeclID is already widely used in
AST and all around the clang project via classes like `LazyPtrDecl` or
calling `ExternalASTSource::getExernalDecl()`. All such uses are via the
raw underlying type of `DeclID` as `uint32_t`. This is not pretty good.

This patch moves the DeclID class family to a new header `AST/DeclID.h`
so that the whole project can use the wrapped class `DeclID`,
`GlobalDeclID` and `LocalDeclID` instead of the raw underlying type.
This can improve the readability and the type safety.

3 files changed, 6 insertions, 7 deletions

diff --git a/clang/lib/Frontend/ASTUnit.cpp b/clang/lib/Frontend/ASTUnit.cpp
index 3610a08..361331d 100644
--- a/clang/lib/Frontend/ASTUnit.cpp
+++ b/clang/lib/Frontend/ASTUnit.cpp
@@ -1067,7 +1067,7 @@ public:
 
   std::vector<Decl *> takeTopLevelDecls() { return std::move(TopLevelDecls); }
 
-  std::vector<serialization::DeclID> takeTopLevelDeclIDs() {
+  std::vector<DeclID> takeTopLevelDeclIDs() {
     return std::move(TopLevelDeclIDs);
   }
 
@@ -1101,7 +1101,7 @@ public:
 private:
   unsigned Hash = 0;
   std::vector<Decl *> TopLevelDecls;
-  std::vector<serialization::DeclID> TopLevelDeclIDs;
+  std::vector<DeclID> TopLevelDeclIDs;
   llvm::SmallVector<ASTUnit::StandaloneDiagnostic, 4> PreambleDiags;
 };
 
diff --git a/clang/lib/Frontend/FrontendAction.cpp b/clang/lib/Frontend/FrontendAction.cpp
index b7c9967..91ce16e 100644
--- a/clang/lib/Frontend/FrontendAction.cpp
+++ b/clang/lib/Frontend/FrontendAction.cpp
@@ -80,7 +80,7 @@ public:
     if (Previous)
       Previous->TypeRead(Idx, T);
   }
-  void DeclRead(serialization::DeclID ID, const Decl *D) override {
+  void DeclRead(DeclID ID, const Decl *D) override {
     if (Previous)
       Previous->DeclRead(ID, D);
   }
@@ -102,7 +102,7 @@ public:
                                    bool DeletePrevious)
       : DelegatingDeserializationListener(Previous, DeletePrevious) {}
 
-  void DeclRead(serialization::DeclID ID, const Decl *D) override {
+  void DeclRead(DeclID ID, const Decl *D) override {
     llvm::outs() << "PCH DECL: " << D->getDeclKindName();
     if (const NamedDecl *ND = dyn_cast<NamedDecl>(D)) {
       llvm::outs() << " - ";
@@ -128,7 +128,7 @@ public:
       : DelegatingDeserializationListener(Previous, DeletePrevious), Ctx(Ctx),
         NamesToCheck(NamesToCheck) {}
 
-  void DeclRead(serialization::DeclID ID, const Decl *D) override {
+  void DeclRead(DeclID ID, const Decl *D) override {
     if (const NamedDecl *ND = dyn_cast<NamedDecl>(D))
       if (NamesToCheck.find(ND->getNameAsString()) != NamesToCheck.end()) {
         unsigned DiagID
diff --git a/clang/lib/Frontend/MultiplexConsumer.cpp b/clang/lib/Frontend/MultiplexConsumer.cpp
index 744ea70..9e885c8 100644
--- a/clang/lib/Frontend/MultiplexConsumer.cpp
+++ b/clang/lib/Frontend/MultiplexConsumer.cpp
@@ -52,8 +52,7 @@ void MultiplexASTDeserializationListener::TypeRead(
     Listeners[i]->TypeRead(Idx, T);
 }
 
-void MultiplexASTDeserializationListener::DeclRead(
-    serialization::DeclID ID, const Decl *D) {
+void MultiplexASTDeserializationListener::DeclRead(DeclID ID, const Decl *D) {
   for (size_t i = 0, e = Listeners.size(); i != e; ++i)
     Listeners[i]->DeclRead(ID, D);
 }