Implement a proper local -> global type ID remapping scheme in the AST

reader. This scheme permits an AST file to be loaded with its type IDs
shifted anywhere in the type ID space. 

At present, the type indices are still allocated in the same boring
way they always have been, just by adding up the number of types in
each PCH file within the chain. However, I've done testing with this
patch by randomly sliding the base indices at load time, to ensure
that remapping is occurring as expected. I may eventually formalize
this in some testing flag, but loading multiple (non-chained) AST
files at once will eventually exercise the same code.

There is one known problem with this patch, which involves name lookup
of operator names (e.g., "x.operator int*()") in cases where multiple
PCH files in the chain. The hash function itself depends on having a
stable type ID, which doesn't happen with chained PCH and *certainly*
doesn't happen when sliding type IDs around. We'll need another
approach. I'll tackle that next.



git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@136693 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 80 insertions, 16 deletions

diff --git a/lib/Serialization/ASTReader.cpp b/lib/Serialization/ASTReader.cpp
index 69fdf10a1a..0241b22f9e 100644
--- a/lib/Serialization/ASTReader.cpp
+++ b/lib/Serialization/ASTReader.cpp
@@ -785,7 +785,10 @@ public:
     case DeclarationName::CXXConstructorName:
     case DeclarationName::CXXDestructorName:
     case DeclarationName::CXXConversionFunctionName:
-      ID.AddInteger((TypeID)Key.Data);
+      if (TypeID(Key.Data) == TypeID(-1))
+        ID.AddInteger((TypeID)Key.Data);
+      else
+        ID.AddInteger(Reader.getLocalTypeID(F, (TypeID)Key.Data));
       break;
     case DeclarationName::CXXOperatorName:
       ID.AddInteger((OverloadedOperatorKind)Key.Data);
@@ -2049,21 +2052,29 @@ ASTReader::ReadASTBlock(Module &F) {
       break;
     }
 
-    case TYPE_OFFSET:
+    case TYPE_OFFSET: {
       if (F.LocalNumTypes != 0) {
         Error("duplicate TYPE_OFFSET record in AST file");
         return Failure;
       }
       F.TypeOffsets = (const uint32_t *)BlobStart;
       F.LocalNumTypes = Record[0];
-      F.BaseTypeID = getTotalNumTypes();
+      F.LocalBaseTypeIndex = Record[1];
+      F.GlobalBaseTypeIndex = getTotalNumTypes();
         
-      // Introduce the global -> local mapping for types within this
-      // AST file.
-      GlobalTypeMap.insert(std::make_pair(getTotalNumTypes() + 1, &F));
-      TypesLoaded.resize(TypesLoaded.size() + F.LocalNumTypes);
+      if (F.LocalNumTypes > 0) {
+        // Introduce the global -> local mapping for types within this module.
+        GlobalTypeMap.insert(std::make_pair(getTotalNumTypes(), &F));
+        
+        // Introduce the local -> global mapping for types within this module.
+        F.TypeRemap.insert(std::make_pair(F.LocalBaseTypeIndex, 
+                             F.GlobalBaseTypeIndex - F.LocalBaseTypeIndex));
+        
+        TypesLoaded.resize(TypesLoaded.size() + F.LocalNumTypes);
+      }
       break;
-
+    }
+        
     case DECL_OFFSET:
       if (F.LocalNumDecls != 0) {
         Error("duplicate DECL_OFFSET record in AST file");
@@ -2278,7 +2289,8 @@ ASTReader::ReadASTBlock(Module &F) {
       
       // Continuous range maps we may be updating in our module.
       ContinuousRangeMap<uint32_t, int, 2>::Builder SLocRemap(F.SLocRemap);
-      
+      ContinuousRangeMap<uint32_t, int, 2>::Builder TypeRemap(F.TypeRemap);
+
       while(Data < DataEnd) {
         uint16_t Len = io::ReadUnalignedLE16(Data);
         StringRef Name = StringRef((const char*)Data, Len);
@@ -2296,7 +2308,7 @@ ASTReader::ReadASTBlock(Module &F) {
         uint32_t SelectorIDOffset = io::ReadUnalignedLE32(Data);
         uint32_t DeclIDOffset = io::ReadUnalignedLE32(Data);
         uint32_t CXXBaseSpecifiersIDOffset = io::ReadUnalignedLE32(Data);
-        uint32_t TypeIDOffset = io::ReadUnalignedLE32(Data);
+        uint32_t TypeIndexOffset = io::ReadUnalignedLE32(Data);
         
         // Source location offset is mapped to OM->SLocEntryBaseOffset.
         SLocRemap.insert(std::make_pair(SLocOffset,
@@ -2309,7 +2321,10 @@ ASTReader::ReadASTBlock(Module &F) {
         (void)SelectorIDOffset;
         (void)DeclIDOffset;
         (void)CXXBaseSpecifiersIDOffset;
-        (void)TypeIDOffset;
+        
+        TypeRemap.insert(std::make_pair(TypeIndexOffset, 
+                                    OM->GlobalBaseTypeIndex - TypeIndexOffset));
+        F.ReverseTypeRemap[OM] = TypeIndexOffset - OM->GlobalBaseTypeIndex;
       }
       break;
     }
@@ -3231,10 +3246,10 @@ void ASTReader::ReadPragmaDiagnosticMappings(Diagnostic &Diag) {
 
 /// \brief Get the correct cursor and offset for loading a type.
 ASTReader::RecordLocation ASTReader::TypeCursorForIndex(unsigned Index) {
-  GlobalTypeMapType::iterator I = GlobalTypeMap.find(Index+1);
+  GlobalTypeMapType::iterator I = GlobalTypeMap.find(Index);
   assert(I != GlobalTypeMap.end() && "Corrupted global type map");
   Module *M = I->second;
-  return RecordLocation(M, M->TypeOffsets[Index - M->BaseTypeID]);
+  return RecordLocation(M, M->TypeOffsets[Index - M->GlobalBaseTypeIndex]);
 }
 
 /// \brief Read and return the type with the given index..
@@ -3979,8 +3994,49 @@ QualType ASTReader::getLocalType(Module &F, unsigned LocalID) {
 
 serialization::TypeID 
 ASTReader::getGlobalTypeID(Module &F, unsigned LocalID) const {
-  // FIXME: Map from local type ID to global type ID.
-  return LocalID;
+  unsigned FastQuals = LocalID & Qualifiers::FastMask;
+  unsigned LocalIndex = LocalID >> Qualifiers::FastWidth;
+  
+  if (LocalIndex < NUM_PREDEF_TYPE_IDS)
+    return LocalID;
+
+  ContinuousRangeMap<uint32_t, int, 2>::iterator I
+    = F.TypeRemap.find(LocalIndex - NUM_PREDEF_TYPE_IDS);
+  assert(I != F.TypeRemap.end() && "Invalid index into type index remap");
+  
+  unsigned GlobalIndex = LocalIndex + I->second;
+  return (GlobalIndex << Qualifiers::FastWidth) | FastQuals;
+}
+
+unsigned ASTReader::getLocalTypeID(Module &M, serialization::TypeID GlobalID) {
+  unsigned FastQuals = GlobalID & Qualifiers::FastMask;
+  unsigned GlobalIndex = GlobalID >> Qualifiers::FastWidth;
+
+  if (GlobalIndex < NUM_PREDEF_TYPE_IDS)
+    return GlobalID;
+  
+  GlobalIndex -= NUM_PREDEF_TYPE_IDS;
+  RecordLocation Loc = TypeCursorForIndex(GlobalIndex);
+  
+  if (Loc.F == &M) {
+    // Simple case: the type ID came from the module we're asked to provide a
+    // type ID for. Shift the index appropriately;
+    unsigned LocalIndex 
+      = GlobalIndex - M.GlobalBaseTypeIndex + M.LocalBaseTypeIndex 
+      + NUM_PREDEF_TYPE_IDS ;
+    return (LocalIndex << Qualifiers::FastWidth) | FastQuals;
+  }
+
+  // Complex case: the type ID came from a module that M depends on, which may
+  // have had some remapping between the IDs used to store it in M and its
+  // location in the global space.
+  llvm::DenseMap<Module *, int>::iterator R = Loc.F->ReverseTypeRemap.find(&M);
+  if (R == Loc.F->ReverseTypeRemap.end())
+    return TypeID(-1); // FIXME: This is a terrible failure case
+  
+  unsigned LocalIndex = GlobalIndex - Loc.F->GlobalBaseTypeIndex 
+                      + R->second + NUM_PREDEF_TYPE_IDS;
+  return (LocalIndex << Qualifiers::FastWidth) | FastQuals;
 }
 
 TypeID ASTReader::GetTypeID(QualType T) const {
@@ -3993,6 +4049,10 @@ TypeIdx ASTReader::GetTypeIdx(QualType T) const {
     return TypeIdx();
   assert(!T.getLocalFastQualifiers());
 
+  // FIXME: Modules can't handle this. It's even dubious with chained PCH,
+  // because the same type (say, int*) can be serialized into different
+  // PCH files within the chain, and there's no way to know which of the
+  // ID numbers we actually want.
   TypeIdxMap::const_iterator I = TypeIdxs.find(T);
   // GetTypeIdx is mostly used for computing the hash of DeclarationNames and
   // comparing keys of ASTDeclContextNameLookupTable.
@@ -5473,7 +5533,8 @@ Module::Module(ModuleKind Kind)
     DeclOffsets(0), BaseDeclID(0),
     LocalNumCXXBaseSpecifiers(0), CXXBaseSpecifiersOffsets(0),
     BaseCXXBaseSpecifiersID(0),
-    LocalNumTypes(0), TypeOffsets(0), BaseTypeID(0), StatCache(0),
+    LocalNumTypes(0), TypeOffsets(0), GlobalBaseTypeIndex(0), 
+    LocalBaseTypeIndex(0), StatCache(0),
     NumPreallocatedPreprocessingEntities(0)
 {}
 
@@ -5515,6 +5576,9 @@ void Module::dump() {
   llvm::errs() << "  Base source location offset: " << SLocEntryBaseOffset 
                << '\n';
   dumpLocalRemap("Source location offset map", SLocRemap);
+  llvm::errs() << "  Base type ID: " << GlobalBaseTypeIndex << '\n'
+               << "  Number of types: " << LocalNumTypes << '\n';
+  dumpLocalRemap("Type ID map", TypeRemap);
 }
 
 Module *ModuleManager::lookup(StringRef Name) {