[Serialization] Stop using DeclID et al for "the next available ID".

This is effectively fallout from 36a44cf where we switched representations of DeclID
and friends, but when I went to add ++ and -- to llvm::PointerEmbeddedInt I realized
it wasn't really intended to be mutated in place, i.e. it doesn't make sense to
increment a DeclID. Represent counters as plain integers instead that get converted
to DeclID when they are first used.

Author: jrose-apple

lib/Serialization/Serialization.cpp

@@ -268,8 +268,7 @@ DeclID Serializer::addLocalDeclContextRef(const DeclContext *DC) {
   if (id != 0)
     return id;
 
-  LastLocalDeclContextID = LastLocalDeclContextID + 1;
-  id = LastLocalDeclContextID;
+  id = ++LastLocalDeclContextID;
   LocalDeclContextsToWrite.push(DC);
   return id;
 }
@@ -294,8 +293,7 @@ DeclContextID Serializer::addDeclContextRef(const DeclContext *DC) {
   if (id)
     return id;
 
-  LastDeclContextID = LastDeclContextID + 1;
-  id = LastDeclContextID;
+  id = ++LastDeclContextID;
   DeclContextsToWrite.push(DC);
 
   return id;
@@ -327,8 +325,7 @@ DeclID Serializer::addDeclRef(const Decl *D, bool forceSerialization) {
   if (paramList)
     GenericContexts[paramList] = D;
 
-  LastDeclID = LastDeclID + 1;
-  id = { LastDeclID, forceSerialization };
+  id = { ++LastDeclID, forceSerialization };
   DeclsAndTypesToWrite.push(D);
   return id.first;
 }
@@ -341,8 +338,7 @@ TypeID Serializer::addTypeRef(Type ty) {
   if (id.first != 0)
     return id.first;
 
-  LastTypeID = LastTypeID + 1;
-  id = { LastTypeID, true };
+  id = { ++LastTypeID, true };
   DeclsAndTypesToWrite.push(ty);
   return id.first;
 }
@@ -355,8 +351,7 @@ IdentifierID Serializer::addIdentifierRef(Identifier ident) {
   if (id != 0)
     return id;
 
-  LastIdentifierID = LastIdentifierID + 1;
-  id = LastIdentifierID;
+  id = ++LastIdentifierID;
   IdentifiersToWrite.push_back(ident);
   return id;
 }
@@ -385,8 +380,7 @@ NormalConformanceID Serializer::addConformanceRef(
   if (conformanceID)
     return conformanceID;
 
-  LastNormalConformanceID = LastNormalConformanceID + 1;
-  conformanceID = LastNormalConformanceID;
+  conformanceID = ++LastNormalConformanceID;
   NormalConformancesToWrite.push(conformance);
 
   return conformanceID;

lib/Serialization/Serialization.h

@@ -178,25 +178,26 @@ class Serializer {
   SmallVector<DeclID, 2> KnownProtocolAdopters[NumKnownProtocols];
 
   /// The last assigned DeclID for decls from this module.
-  DeclID LastDeclID = 0;
+  uint32_t /*DeclID*/ LastDeclID = 0;
 
   /// The last assigned DeclContextID for decl contexts from this module.
-  DeclContextID LastDeclContextID = 0;
+  uint32_t /*DeclContextID*/ LastDeclContextID = 0;
 
   /// The last assigned DeclContextID for local decl contexts from this module.
-  DeclContextID LastLocalDeclContextID = 0;
+  uint32_t /*DeclContextID*/ LastLocalDeclContextID = 0;
 
   /// The last assigned NormalConformanceID for decl contexts from this module.
-  NormalConformanceID LastNormalConformanceID = 0;
+  uint32_t /*NormalConformanceID*/ LastNormalConformanceID = 0;
 
   /// The last assigned DeclID for types from this module.
-  TypeID LastTypeID = 0;
+  uint32_t /*TypeID*/ LastTypeID = 0;
 
   /// The last assigned IdentifierID for types from this module.
   ///
   /// Note that special module IDs must not be valid IdentifierIDs, except that
   /// 0 will always represent the empty identifier.
-  IdentifierID LastIdentifierID = serialization::NUM_SPECIAL_MODULES - 1;
+  uint32_t /*IdentifierID*/ LastIdentifierID =
+      serialization::NUM_SPECIAL_MODULES - 1;
 
   /// Returns the record code for serializing the given vector of offsets.
   ///

lib/Serialization/SerializeSIL.cpp

@@ -115,7 +115,7 @@ namespace {
     SmallVector<uint64_t, 64> ScratchRecord;
 
     /// In case we want to encode the relative of InstID vs ValueID.
-    ValueID InstID = 0;
+    uint32_t /*ValueID*/ InstID = 0;
 
     llvm::DenseMap<const ValueBase*, ValueID> ValueIDs;
     ValueID addValueRef(const ValueBase *Val);
@@ -128,25 +128,25 @@ namespace {
     Table FuncTable;
     std::vector<BitOffset> Funcs;
     /// The current function ID.
-    DeclID FuncID = 1;
+    uint32_t /*DeclID*/ NextFuncID = 1;
 
     /// Maps class name to a VTable ID.
     Table VTableList;
     /// Holds the list of VTables.
     std::vector<BitOffset> VTableOffset;
-    DeclID VTableID = 1;
+    uint32_t /*DeclID*/ NextVTableID = 1;
 
     /// Maps global variable name to an ID.
     Table GlobalVarList;
     /// Holds the list of SIL global variables.
     std::vector<BitOffset> GlobalVarOffset;
-    DeclID GlobalVarID = 1;
+    uint32_t /*DeclID*/ NextGlobalVarID = 1;
 
     /// Maps witness table identifier to an ID.
     Table WitnessTableList;
     /// Holds the list of WitnessTables.
     std::vector<BitOffset> WitnessTableOffset;
-    DeclID WitnessTableID = 1;
+    uint32_t /*DeclID*/ NextWitnessTableID = 1;
 
     /// Give each SILBasicBlock a unique ID.
     llvm::DenseMap<const SILBasicBlock*, unsigned> BasicBlockMap;
@@ -224,8 +224,7 @@ void SILSerializer::writeSILFunction(const SILFunction &F, bool DeclOnly) {
   ValueIDs.clear();
   InstID = 0;
 
-  FuncTable[Ctx.getIdentifier(F.getName())] = FuncID;
-  FuncID = FuncID + 1;
+  FuncTable[Ctx.getIdentifier(F.getName())] = NextFuncID++;
   Funcs.push_back(Out.GetCurrentBitNo());
   unsigned abbrCode = SILAbbrCodes[SILFunctionLayout::Code];
   TypeID FnID = S.addTypeRef(F.getLoweredType().getSwiftType());
@@ -1444,7 +1443,7 @@ void SILSerializer::writeSILInstruction(const SILInstruction &SI) {
   // Non-void values get registered in the value table.
   if (SI.hasValue()) {
     addValueRef(&SI);
-    InstID = InstID + 1;
+    ++InstID;
   }
 }
 
@@ -1504,8 +1503,7 @@ void SILSerializer::writeIndexTables() {
 }
 
 void SILSerializer::writeSILGlobalVar(const SILGlobalVariable &g) {
-  GlobalVarList[Ctx.getIdentifier(g.getName())] = GlobalVarID;
-  GlobalVarID = GlobalVarID + 1;
+  GlobalVarList[Ctx.getIdentifier(g.getName())] = NextGlobalVarID++;
   GlobalVarOffset.push_back(Out.GetCurrentBitNo());
   TypeID TyID = S.addTypeRef(g.getLoweredType().getSwiftType());
   DeclID dID = S.addDeclRef(g.getDecl());
@@ -1518,8 +1516,7 @@ void SILSerializer::writeSILGlobalVar(const SILGlobalVariable &g) {
 }
 
 void SILSerializer::writeSILVTable(const SILVTable &vt) {
-  VTableList[vt.getClass()->getName()] = VTableID;
-  VTableID = VTableID + 1;
+  VTableList[vt.getClass()->getName()] = NextVTableID++;
   VTableOffset.push_back(Out.GetCurrentBitNo());
   VTableLayout::emitRecord(Out, ScratchRecord, SILAbbrCodes[VTableLayout::Code],
                            S.addDeclRef(vt.getClass()));
@@ -1538,8 +1535,7 @@ void SILSerializer::writeSILVTable(const SILVTable &vt) {
 }
 
 void SILSerializer::writeSILWitnessTable(const SILWitnessTable &wt) {
-  WitnessTableList[wt.getIdentifier()] = WitnessTableID;
-  WitnessTableID = WitnessTableID + 1;
+  WitnessTableList[wt.getIdentifier()] = NextWitnessTableID++;
   WitnessTableOffset.push_back(Out.GetCurrentBitNo());
 
   WitnessTableLayout::emitRecord(