[CodeView] Decouple record deserialization from visitor dispatch.

Until now, our use case for the visitor has been to take a stream of bytes
representing a type stream, deserialize the records in sequence, and do
something with them, where "something" is determined by how the user
implements a particular set of callbacks on an abstract class.

For actually writing PDBs, however, we want to do the reverse. We have
some kind of description of the list of records in their in-memory format,
and we want to process each one. Perhaps by serializing them to a byte
stream, or perhaps by converting them from one description format (Yaml)
to another (in-memory representation).

This was difficult in the current model because deserialization and
invoking the callbacks were tightly coupled.

With this patch we change this so that TypeDeserializer is itself an
implementation of the particular set of callbacks. This decouples
deserialization from the iteration over a list of records and invocation
of the callbacks.  TypeDeserializer is initialized with another
implementation of the callback interface, so that upon deserialization it
can pass the deserialized record through to the next set of callbacks. In
a sense this is like an implementation of the Decorator design pattern,
where the Deserializer is a decorator.

This will be useful for writing Pdbs from yaml, where we have a
description of the type records in Yaml format. In this case, the visitor
implementation would have each visitation callback method implemented in
such a way as to extract the proper set of fields from the Yaml, and it
could maintain state that builds up a list of these records. Finally at
the end we can pass this information through to another set of callbacks
which serializes them into a byte stream.

Reviewed By: majnemer, ruiu, rnk
Differential Revision: https://reviews.llvm.org/D23177

llvm-svn: 277871

1 files changed, 35 insertions, 36 deletions

diff --git a/llvm/lib/CodeGen/AsmPrinter/CodeViewDebug.cpp b/llvm/lib/CodeGen/AsmPrinter/CodeViewDebug.cpp
index 9d5d2127359..52d7b45d37b 100644
--- a/llvm/lib/CodeGen/AsmPrinter/CodeViewDebug.cpp
+++ b/llvm/lib/CodeGen/AsmPrinter/CodeViewDebug.cpp
@@ -212,7 +212,7 @@ TypeIndex CodeViewDebug::getScopeIndex(const DIScope *Scope) {
   // Build the fully qualified name of the scope.
   std::string ScopeName = getFullyQualifiedName(Scope);
   TypeIndex TI =
-      TypeTable.writeStringId(StringIdRecord(TypeIndex(), ScopeName));
+      TypeTable.writeKnownType(StringIdRecord(TypeIndex(), ScopeName));
   return recordTypeIndexForDINode(Scope, TI);
 }
 
@@ -237,12 +237,12 @@ TypeIndex CodeViewDebug::getFuncIdForSubprogram(const DISubprogram *SP) {
     TypeIndex ClassType = getTypeIndex(Class);
     MemberFuncIdRecord MFuncId(ClassType, getMemberFunctionType(SP, Class),
                                DisplayName);
-    TI = TypeTable.writeMemberFuncId(MFuncId);
+    TI = TypeTable.writeKnownType(MFuncId);
   } else {
     // Otherwise, this must be a free function.
     TypeIndex ParentScope = getScopeIndex(Scope);
     FuncIdRecord FuncId(ParentScope, getTypeIndex(SP->getType()), DisplayName);
-    TI = TypeTable.writeFuncId(FuncId);
+    TI = TypeTable.writeKnownType(FuncId);
   }
 
   return recordTypeIndexForDINode(SP, TI);
@@ -1030,7 +1030,7 @@ TypeIndex CodeViewDebug::lowerTypeArray(const DICompositeType *Ty) {
     StringRef Name = (i == 0) ? Ty->getName() : "";
     // Update the element size and element type index for subsequent subranges.
     ElementSize *= Count;
-    ElementTypeIndex = TypeTable.writeArray(
+    ElementTypeIndex = TypeTable.writeKnownType(
         ArrayRecord(ElementTypeIndex, IndexType, ElementSize, Name));
   }
 
@@ -1174,7 +1174,7 @@ TypeIndex CodeViewDebug::lowerTypePointer(const DIDerivedType *Ty) {
   // do.
   PointerOptions PO = PointerOptions::None;
   PointerRecord PR(PointeeTI, PK, PM, PO, Ty->getSizeInBits() / 8);
-  return TypeTable.writePointer(PR);
+  return TypeTable.writeKnownType(PR);
 }
 
 static PointerToMemberRepresentation
@@ -1225,7 +1225,7 @@ TypeIndex CodeViewDebug::lowerTypeMemberPointer(const DIDerivedType *Ty) {
   MemberPointerInfo MPI(
       ClassTI, translatePtrToMemberRep(SizeInBytes, IsPMF, Ty->getFlags()));
   PointerRecord PR(PointeeTI, PK, PM, PO, SizeInBytes, MPI);
-  return TypeTable.writePointer(PR);
+  return TypeTable.writeKnownType(PR);
 }
 
 /// Given a DWARF calling convention, get the CodeView equivalent. If we don't
@@ -1272,7 +1272,7 @@ TypeIndex CodeViewDebug::lowerTypeModifier(const DIDerivedType *Ty) {
     return I->second;
 
   ModifierRecord MR(ModifiedTI, Mods);
-  return TypeTable.writeModifier(MR);
+  return TypeTable.writeKnownType(MR);
 }
 
 TypeIndex CodeViewDebug::lowerTypeFunction(const DISubroutineType *Ty) {
@@ -1289,13 +1289,13 @@ TypeIndex CodeViewDebug::lowerTypeFunction(const DISubroutineType *Ty) {
   }
 
   ArgListRecord ArgListRec(TypeRecordKind::ArgList, ArgTypeIndices);
-  TypeIndex ArgListIndex = TypeTable.writeArgList(ArgListRec);
+  TypeIndex ArgListIndex = TypeTable.writeKnownType(ArgListRec);
 
   CallingConvention CC = dwarfCCToCodeView(Ty->getCC());
 
   ProcedureRecord Procedure(ReturnTypeIndex, CC, FunctionOptions::None,
                             ArgTypeIndices.size(), ArgListIndex);
-  return TypeTable.writeProcedure(Procedure);
+  return TypeTable.writeKnownType(Procedure);
 }
 
 TypeIndex CodeViewDebug::lowerTypeMemberFunction(const DISubroutineType *Ty,
@@ -1322,14 +1322,14 @@ TypeIndex CodeViewDebug::lowerTypeMemberFunction(const DISubroutineType *Ty,
   }
 
   ArgListRecord ArgListRec(TypeRecordKind::ArgList, ArgTypeIndices);
-  TypeIndex ArgListIndex = TypeTable.writeArgList(ArgListRec);
+  TypeIndex ArgListIndex = TypeTable.writeKnownType(ArgListRec);
 
   CallingConvention CC = dwarfCCToCodeView(Ty->getCC());
 
   // TODO: Need to use the correct values for:
   //       FunctionOptions
   //       ThisPointerAdjustment.
-  TypeIndex TI = TypeTable.writeMemberFunction(MemberFunctionRecord(
+  TypeIndex TI = TypeTable.writeKnownType(MemberFunctionRecord(
       ReturnTypeIndex, ClassType, ThisTypeIndex, CC, FunctionOptions::None,
       ArgTypeIndices.size(), ArgListIndex, ThisAdjustment));
 
@@ -1428,7 +1428,7 @@ TypeIndex CodeViewDebug::lowerTypeEnum(const DICompositeType *Ty) {
       // We assume that the frontend provides all members in source declaration
       // order, which is what MSVC does.
       if (auto *Enumerator = dyn_cast_or_null<DIEnumerator>(Element)) {
-        Fields.writeEnumerator(EnumeratorRecord(
+        Fields.writeMemberType(EnumeratorRecord(
             MemberAccess::Public, APSInt::getUnsigned(Enumerator->getValue()),
             Enumerator->getName()));
         EnumeratorCount++;
@@ -1439,9 +1439,9 @@ TypeIndex CodeViewDebug::lowerTypeEnum(const DICompositeType *Ty) {
 
   std::string FullName = getFullyQualifiedName(Ty);
 
-  return TypeTable.writeEnum(EnumRecord(EnumeratorCount, CO, FTI, FullName,
-                                        Ty->getIdentifier(),
-                                        getTypeIndex(Ty->getBaseType())));
+  return TypeTable.writeKnownType(EnumRecord(EnumeratorCount, CO, FTI, FullName,
+                                             Ty->getIdentifier(),
+                                             getTypeIndex(Ty->getBaseType())));
 }
 
 //===----------------------------------------------------------------------===//
@@ -1536,7 +1536,7 @@ TypeIndex CodeViewDebug::lowerTypeClass(const DICompositeType *Ty) {
   ClassOptions CO =
       ClassOptions::ForwardReference | getCommonClassOptions(Ty);
   std::string FullName = getFullyQualifiedName(Ty);
-  TypeIndex FwdDeclTI = TypeTable.writeClass(ClassRecord(
+  TypeIndex FwdDeclTI = TypeTable.writeKnownType(ClassRecord(
       Kind, 0, CO, HfaKind::None, WindowsRTClassKind::None, TypeIndex(),
       TypeIndex(), TypeIndex(), 0, FullName, Ty->getIdentifier()));
   if (!Ty->isForwardDecl())
@@ -1562,12 +1562,12 @@ TypeIndex CodeViewDebug::lowerCompleteTypeClass(const DICompositeType *Ty) {
 
   uint64_t SizeInBytes = Ty->getSizeInBits() / 8;
 
-  TypeIndex ClassTI = TypeTable.writeClass(ClassRecord(
+  TypeIndex ClassTI = TypeTable.writeKnownType(ClassRecord(
       Kind, FieldCount, CO, HfaKind::None, WindowsRTClassKind::None, FieldTI,
       TypeIndex(), VShapeTI, SizeInBytes, FullName, Ty->getIdentifier()));
 
-  TypeTable.writeUdtSourceLine(UdtSourceLineRecord(
-      ClassTI, TypeTable.writeStringId(StringIdRecord(
+  TypeTable.writeKnownType(UdtSourceLineRecord(
+      ClassTI, TypeTable.writeKnownType(StringIdRecord(
                    TypeIndex(0x0), getFullFilepath(Ty->getFile()))),
       Ty->getLine()));
 
@@ -1580,9 +1580,8 @@ TypeIndex CodeViewDebug::lowerTypeUnion(const DICompositeType *Ty) {
   ClassOptions CO =
       ClassOptions::ForwardReference | getCommonClassOptions(Ty);
   std::string FullName = getFullyQualifiedName(Ty);
-  TypeIndex FwdDeclTI =
-      TypeTable.writeUnion(UnionRecord(0, CO, HfaKind::None, TypeIndex(), 0,
-                                       FullName, Ty->getIdentifier()));
+  TypeIndex FwdDeclTI = TypeTable.writeKnownType(UnionRecord(
+      0, CO, HfaKind::None, TypeIndex(), 0, FullName, Ty->getIdentifier()));
   if (!Ty->isForwardDecl())
     DeferredCompleteTypes.push_back(Ty);
   return FwdDeclTI;
@@ -1602,12 +1601,12 @@ TypeIndex CodeViewDebug::lowerCompleteTypeUnion(const DICompositeType *Ty) {
   uint64_t SizeInBytes = Ty->getSizeInBits() / 8;
   std::string FullName = getFullyQualifiedName(Ty);
 
-  TypeIndex UnionTI = TypeTable.writeUnion(
+  TypeIndex UnionTI = TypeTable.writeKnownType(
       UnionRecord(FieldCount, CO, HfaKind::None, FieldTI, SizeInBytes, FullName,
                   Ty->getIdentifier()));
 
-  TypeTable.writeUdtSourceLine(UdtSourceLineRecord(
-      UnionTI, TypeTable.writeStringId(StringIdRecord(
+  TypeTable.writeKnownType(UdtSourceLineRecord(
+      UnionTI, TypeTable.writeKnownType(StringIdRecord(
                    TypeIndex(0x0), getFullFilepath(Ty->getFile()))),
       Ty->getLine()));
 
@@ -1634,14 +1633,14 @@ CodeViewDebug::lowerRecordFieldList(const DICompositeType *Ty) {
       unsigned VBPtrOffset = 0;
       // FIXME: Despite the accessor name, the offset is really in bytes.
       unsigned VBTableIndex = I->getOffsetInBits() / 4;
-      Fields.writeVirtualBaseClass(VirtualBaseClassRecord(
+      Fields.writeMemberType(VirtualBaseClassRecord(
           translateAccessFlags(Ty->getTag(), I->getFlags()),
           getTypeIndex(I->getBaseType()), getVBPTypeIndex(), VBPtrOffset,
           VBTableIndex));
     } else {
       assert(I->getOffsetInBits() % 8 == 0 &&
              "bases must be on byte boundaries");
-      Fields.writeBaseClass(BaseClassRecord(
+      Fields.writeMemberType(BaseClassRecord(
           translateAccessFlags(Ty->getTag(), I->getFlags()),
           getTypeIndex(I->getBaseType()), I->getOffsetInBits() / 8));
     }
@@ -1656,7 +1655,7 @@ CodeViewDebug::lowerRecordFieldList(const DICompositeType *Ty) {
         translateAccessFlags(Ty->getTag(), Member->getFlags());
 
     if (Member->isStaticMember()) {
-      Fields.writeStaticDataMember(
+      Fields.writeMemberType(
           StaticDataMemberRecord(Access, MemberBaseType, MemberName));
       MemberCount++;
       continue;
@@ -1672,11 +1671,11 @@ CodeViewDebug::lowerRecordFieldList(const DICompositeType *Ty) {
         MemberOffsetInBits = CI->getZExtValue() + MemberInfo.BaseOffset;
       }
       StartBitOffset -= MemberOffsetInBits;
-      MemberBaseType = TypeTable.writeBitField(BitFieldRecord(
+      MemberBaseType = TypeTable.writeKnownType(BitFieldRecord(
           MemberBaseType, Member->getSizeInBits(), StartBitOffset));
     }
     uint64_t MemberOffsetInBytes = MemberOffsetInBits / 8;
-    Fields.writeDataMember(DataMemberRecord(Access, MemberBaseType,
+    Fields.writeMemberType(DataMemberRecord(Access, MemberBaseType,
                                             MemberOffsetInBytes, MemberName));
     MemberCount++;
   }
@@ -1703,11 +1702,11 @@ CodeViewDebug::lowerRecordFieldList(const DICompositeType *Ty) {
     }
     assert(Methods.size() > 0 && "Empty methods map entry");
     if (Methods.size() == 1)
-      Fields.writeOneMethod(Methods[0]);
+      Fields.writeMemberType(Methods[0]);
     else {
       TypeIndex MethodList =
-          TypeTable.writeMethodOverloadList(MethodOverloadListRecord(Methods));
-      Fields.writeOverloadedMethod(
+          TypeTable.writeKnownType(MethodOverloadListRecord(Methods));
+      Fields.writeMemberType(
           OverloadedMethodRecord(Methods.size(), MethodList, Name));
     }
   }
@@ -1715,7 +1714,7 @@ CodeViewDebug::lowerRecordFieldList(const DICompositeType *Ty) {
   // Create nested classes.
   for (const DICompositeType *Nested : Info.NestedClasses) {
     NestedTypeRecord R(getTypeIndex(DITypeRef(Nested)), Nested->getName());
-    Fields.writeNestedType(R);
+    Fields.writeMemberType(R);
     MemberCount++;
   }
 
@@ -1728,7 +1727,7 @@ TypeIndex CodeViewDebug::getVBPTypeIndex() {
   if (!VBPType.getIndex()) {
     // Make a 'const int *' type.
     ModifierRecord MR(TypeIndex::Int32(), ModifierOptions::Const);
-    TypeIndex ModifiedTI = TypeTable.writeModifier(MR);
+    TypeIndex ModifiedTI = TypeTable.writeKnownType(MR);
 
     PointerKind PK = getPointerSizeInBytes() == 8 ? PointerKind::Near64
                                                   : PointerKind::Near32;
@@ -1736,7 +1735,7 @@ TypeIndex CodeViewDebug::getVBPTypeIndex() {
     PointerOptions PO = PointerOptions::None;
     PointerRecord PR(ModifiedTI, PK, PM, PO, getPointerSizeInBytes());
 
-    VBPType = TypeTable.writePointer(PR);
+    VBPType = TypeTable.writeKnownType(PR);
   }
 
   return VBPType;