[CodeView] Simplify the use of visiting type records & streams.

There is often a lot of boilerplate code required to visit a type
record or type stream.  The #1 use case is that you have a sequence
of bytes that represent one or more records, and you want to
deserialize each one, switch on it, and call a callback with the
deserialized record that the user can examine.  Currently this
requires at least 6 lines of code:

  codeview::TypeVisitorCallbackPipeline Pipeline;
  Pipeline.addCallbackToPipeline(Deserializer);
  Pipeline.addCallbackToPipeline(MyCallbacks);

  codeview::CVTypeVisitor Visitor(Pipeline);
  consumeError(Visitor.visitTypeRecord(Record));

With this patch, it becomes one line of code:

  consumeError(codeview::visitTypeRecord(Record, MyCallbacks));

This is done by having the deserialization happen internally inside
of the visitTypeRecord function.  Since this is occasionally not
desirable, the function provides a 3rd parameter that can be used
to change this behavior.

Hopefully this can significantly reduce the barrier to entry
to using the visitation infrastructure.

Differential Revision: https://reviews.llvm.org/D33245

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@303271 91177308-0d34-0410-b5e6-96231b3b80d8

Author: Zachary Turner

include/llvm/DebugInfo/CodeView/CVTypeVisitor.h

@@ -28,7 +28,7 @@ class CVTypeVisitor {
 
   Error visitTypeRecord(CVType &Record, TypeIndex Index);
   Error visitTypeRecord(CVType &Record);
-  Error visitMemberRecord(CVMemberRecord &Record);
+  Error visitMemberRecord(CVMemberRecord Record);
 
   /// Visits the type records in Data. Sets the error flag on parse failures.
   Error visitTypeStream(const CVTypeArray &Types);
@@ -47,6 +47,36 @@ class CVTypeVisitor {
   TinyPtrVector<TypeServerHandler *> Handlers;
 };
 
+enum VisitorDataSource {
+  VDS_BytesPresent, // The record bytes are passed into the the visitation
+                    // function.  The algorithm should first deserialize them
+                    // before passing them on through the pipeline.
+  VDS_BytesExternal // The record bytes are not present, and it is the
+                    // responsibility of the visitor callback interface to
+                    // supply the bytes.
+};
+
+Error visitTypeRecord(CVType &Record, TypeIndex Index,
+                      TypeVisitorCallbacks &Callbacks,
+                      VisitorDataSource Source = VDS_BytesPresent,
+                      TypeServerHandler *TS = nullptr);
+Error visitTypeRecord(CVType &Record, TypeVisitorCallbacks &Callbacks,
+                      VisitorDataSource Source = VDS_BytesPresent,
+                      TypeServerHandler *TS = nullptr);
+
+Error visitMemberRecord(CVMemberRecord Record, TypeVisitorCallbacks &Callbacks,
+                        VisitorDataSource Source = VDS_BytesPresent);
+Error visitMemberRecord(TypeLeafKind Kind, ArrayRef<uint8_t> Record,
+                        TypeVisitorCallbacks &Callbacks);
+
+Error visitMemberRecordStream(ArrayRef<uint8_t> FieldList,
+                              TypeVisitorCallbacks &Callbacks);
+
+Error visitTypeStream(const CVTypeArray &Types, TypeVisitorCallbacks &Callbacks,
+                      TypeServerHandler *TS = nullptr);
+Error visitTypeStream(CVTypeRange Types, TypeVisitorCallbacks &Callbacks,
+                      TypeServerHandler *TS = nullptr);
+
 } // end namespace codeview
 } // end namespace llvm
 

include/llvm/DebugInfo/CodeView/RandomAccessTypeVisitor.h

@@ -11,13 +11,10 @@
 #define LLVM_DEBUGINFO_CODEVIEW_RANDOMACCESSTYPEVISITOR_H
 
 #include "llvm/ADT/TinyPtrVector.h"
-#include "llvm/DebugInfo/CodeView/CVTypeVisitor.h"
 #include "llvm/DebugInfo/CodeView/TypeDatabase.h"
 #include "llvm/DebugInfo/CodeView/TypeDatabaseVisitor.h"
-#include "llvm/DebugInfo/CodeView/TypeDeserializer.h"
 #include "llvm/DebugInfo/CodeView/TypeIndex.h"
 #include "llvm/DebugInfo/CodeView/TypeRecord.h"
-#include "llvm/DebugInfo/CodeView/TypeVisitorCallbackPipeline.h"
 #include "llvm/Support/Error.h"
 
 namespace llvm {
@@ -73,18 +70,6 @@ class RandomAccessTypeVisitor {
   /// The database visitor which adds new records to the database.
   TypeDatabaseVisitor DatabaseVisitor;
 
-  /// The deserializer which deserializes new records.
-  TypeDeserializer Deserializer;
-
-  /// The visitation callback pipeline to use.  By default this contains a
-  /// deserializer and a type database visitor.  But the callback specified
-  /// in the constructor is also added.
-  TypeVisitorCallbackPipeline Pipeline;
-
-  /// The visitor used to visit the internal pipeline for deserialization and
-  /// database maintenance.
-  CVTypeVisitor InternalVisitor;
-
   /// A vector mapping type indices to type offset.  For every record that has
   /// been visited, contains the absolute offset of that record in the record
   /// array.

include/llvm/DebugInfo/PDB/Native/TpiStream.h

@@ -51,6 +51,7 @@ class TpiStream {
   HashTable &getHashAdjusters();
 
   codeview::CVTypeRange types(bool *HadError) const;
+  const codeview::CVTypeArray &typeArray() const { return TypeRecords; }
 
   Error commit();
 

lib/CodeGen/AsmPrinter/CodeViewDebug.cpp

@@ -501,7 +501,7 @@ void CodeViewDebug::emitTypeInformation() {
       Error E = Reader.readArray(Types, Reader.getLength());
       if (!E) {
         TypeVisitorCallbacks C;
-        E = CVTypeVisitor(C).visitTypeStream(Types);
+        E = codeview::visitTypeStream(Types, C);
       }
       if (E) {
         logAllUnhandledErrors(std::move(E), errs(), "error: ");

lib/DebugInfo/CodeView/CVTypeDumper.cpp

@@ -11,7 +11,6 @@
 #include "llvm/DebugInfo/CodeView/CVTypeVisitor.h"
 #include "llvm/DebugInfo/CodeView/TypeDatabase.h"
 #include "llvm/DebugInfo/CodeView/TypeDatabaseVisitor.h"
-#include "llvm/DebugInfo/CodeView/TypeDeserializer.h"
 #include "llvm/DebugInfo/CodeView/TypeRecord.h"
 #include "llvm/DebugInfo/CodeView/TypeVisitorCallbackPipeline.h"
 #include "llvm/Support/BinaryByteStream.h"
@@ -21,38 +20,23 @@ using namespace llvm::codeview;
 
 Error CVTypeDumper::dump(const CVType &Record, TypeVisitorCallbacks &Dumper) {
   TypeDatabaseVisitor DBV(TypeDB);
-  TypeDeserializer Deserializer;
   TypeVisitorCallbackPipeline Pipeline;
-  Pipeline.addCallbackToPipeline(Deserializer);
   Pipeline.addCallbackToPipeline(DBV);
   Pipeline.addCallbackToPipeline(Dumper);
 
-  CVTypeVisitor Visitor(Pipeline);
-  if (Handler)
-    Visitor.addTypeServerHandler(*Handler);
-
   CVType RecordCopy = Record;
-  if (auto EC = Visitor.visitTypeRecord(RecordCopy))
-    return EC;
-  return Error::success();
+  return codeview::visitTypeRecord(RecordCopy, Pipeline, VDS_BytesPresent,
+                                   Handler);
 }
 
 Error CVTypeDumper::dump(const CVTypeArray &Types,
                          TypeVisitorCallbacks &Dumper) {
   TypeDatabaseVisitor DBV(TypeDB);
-  TypeDeserializer Deserializer;
   TypeVisitorCallbackPipeline Pipeline;
-  Pipeline.addCallbackToPipeline(Deserializer);
   Pipeline.addCallbackToPipeline(DBV);
   Pipeline.addCallbackToPipeline(Dumper);
 
-  CVTypeVisitor Visitor(Pipeline);
-  if (Handler)
-    Visitor.addTypeServerHandler(*Handler);
-
-  if (auto EC = Visitor.visitTypeStream(Types))
-    return EC;
-  return Error::success();
+  return codeview::visitTypeStream(Types, Pipeline, Handler);
 }
 
 Error CVTypeDumper::dump(ArrayRef<uint8_t> Data, TypeVisitorCallbacks &Dumper) {

lib/DebugInfo/CodeView/CVTypeVisitor.cpp

@@ -59,13 +59,8 @@ static Expected<TypeServer2Record> deserializeTypeServerRecord(CVType &Record) {
   };
 
   TypeServer2Record R(TypeRecordKind::TypeServer2);
-  TypeDeserializer Deserializer;
   StealTypeServerVisitor Thief(R);
-  TypeVisitorCallbackPipeline Pipeline;
-  Pipeline.addCallbackToPipeline(Deserializer);
-  Pipeline.addCallbackToPipeline(Thief);
-  CVTypeVisitor Visitor(Pipeline);
-  if (auto EC = Visitor.visitTypeRecord(Record))
+  if (auto EC = visitTypeRecord(Record, Thief))
     return std::move(EC);
 
   return R;
@@ -178,7 +173,7 @@ static Error visitMemberRecord(CVMemberRecord &Record,
   return Error::success();
 }
 
-Error CVTypeVisitor::visitMemberRecord(CVMemberRecord &Record) {
+Error CVTypeVisitor::visitMemberRecord(CVMemberRecord Record) {
   return ::visitMemberRecord(Record, Callbacks);
 }
 
@@ -224,3 +219,93 @@ Error CVTypeVisitor::visitFieldListMemberStream(ArrayRef<uint8_t> Data) {
   BinaryStreamReader SR(S);
   return visitFieldListMemberStream(SR);
 }
+
+namespace {
+struct FieldListVisitHelper {
+  FieldListVisitHelper(TypeVisitorCallbacks &Callbacks, ArrayRef<uint8_t> Data,
+                       VisitorDataSource Source)
+      : Stream(Data, llvm::support::little), Reader(Stream),
+        Deserializer(Reader),
+        Visitor((Source == VDS_BytesPresent) ? Pipeline : Callbacks) {
+    if (Source == VDS_BytesPresent) {
+      Pipeline.addCallbackToPipeline(Deserializer);
+      Pipeline.addCallbackToPipeline(Callbacks);
+    }
+  }
+
+  BinaryByteStream Stream;
+  BinaryStreamReader Reader;
+  FieldListDeserializer Deserializer;
+  TypeVisitorCallbackPipeline Pipeline;
+  CVTypeVisitor Visitor;
+};
+
+struct VisitHelper {
+  VisitHelper(TypeVisitorCallbacks &Callbacks, VisitorDataSource Source,
+              TypeServerHandler *TS)
+      : Visitor((Source == VDS_BytesPresent) ? Pipeline : Callbacks) {
+    if (TS)
+      Visitor.addTypeServerHandler(*TS);
+    if (Source == VDS_BytesPresent) {
+      Pipeline.addCallbackToPipeline(Deserializer);
+      Pipeline.addCallbackToPipeline(Callbacks);
+    }
+  }
+
+  TypeDeserializer Deserializer;
+  TypeVisitorCallbackPipeline Pipeline;
+  CVTypeVisitor Visitor;
+};
+}
+
+Error llvm::codeview::visitTypeRecord(CVType &Record, TypeIndex Index,
+                                      TypeVisitorCallbacks &Callbacks,
+                                      VisitorDataSource Source,
+                                      TypeServerHandler *TS) {
+  VisitHelper Helper(Callbacks, Source, TS);
+  return Helper.Visitor.visitTypeRecord(Record, Index);
+}
+
+Error llvm::codeview::visitTypeRecord(CVType &Record,
+                                      TypeVisitorCallbacks &Callbacks,
+                                      VisitorDataSource Source,
+                                      TypeServerHandler *TS) {
+  VisitHelper Helper(Callbacks, Source, TS);
+  return Helper.Visitor.visitTypeRecord(Record);
+}
+
+Error llvm::codeview::visitMemberRecordStream(ArrayRef<uint8_t> FieldList,
+                                              TypeVisitorCallbacks &Callbacks) {
+  CVTypeVisitor Visitor(Callbacks);
+  return Visitor.visitFieldListMemberStream(FieldList);
+}
+
+Error llvm::codeview::visitMemberRecord(CVMemberRecord Record,
+                                        TypeVisitorCallbacks &Callbacks,
+                                        VisitorDataSource Source) {
+  FieldListVisitHelper Helper(Callbacks, Record.Data, Source);
+  return Helper.Visitor.visitMemberRecord(Record);
+}
+
+Error llvm::codeview::visitMemberRecord(TypeLeafKind Kind,
+                                        ArrayRef<uint8_t> Record,
+                                        TypeVisitorCallbacks &Callbacks) {
+  CVMemberRecord R;
+  R.Data = Record;
+  R.Kind = Kind;
+  return visitMemberRecord(R, Callbacks, VDS_BytesPresent);
+}
+
+Error llvm::codeview::visitTypeStream(const CVTypeArray &Types,
+                                      TypeVisitorCallbacks &Callbacks,
+                                      TypeServerHandler *TS) {
+  VisitHelper Helper(Callbacks, VDS_BytesPresent, TS);
+  return Helper.Visitor.visitTypeStream(Types);
+}
+
+Error llvm::codeview::visitTypeStream(CVTypeRange Types,
+                                      TypeVisitorCallbacks &Callbacks,
+                                      TypeServerHandler *TS) {
+  VisitHelper Helper(Callbacks, VDS_BytesPresent, TS);
+  return Helper.Visitor.visitTypeStream(Types);
+}

lib/DebugInfo/CodeView/RandomAccessTypeVisitor.cpp

@@ -9,6 +9,7 @@
 
 #include "llvm/DebugInfo/CodeView/RandomAccessTypeVisitor.h"
 
+#include "llvm/DebugInfo/CodeView/CVTypeVisitor.h"
 #include "llvm/DebugInfo/CodeView/TypeDatabase.h"
 #include "llvm/DebugInfo/CodeView/TypeServerHandler.h"
 #include "llvm/DebugInfo/CodeView/TypeVisitorCallbacks.h"
@@ -20,9 +21,7 @@ RandomAccessTypeVisitor::RandomAccessTypeVisitor(
     const CVTypeArray &Types, uint32_t NumRecords,
     PartialOffsetArray PartialOffsets)
     : Database(NumRecords), Types(Types), DatabaseVisitor(Database),
-      InternalVisitor(Pipeline), PartialOffsets(PartialOffsets) {
-  Pipeline.addCallbackToPipeline(Deserializer);
-  Pipeline.addCallbackToPipeline(DatabaseVisitor);
+      PartialOffsets(PartialOffsets) {
 
   KnownOffsets.resize(Database.capacity());
 }
@@ -38,8 +37,7 @@ Error RandomAccessTypeVisitor::visitTypeIndex(TypeIndex TI,
 
   assert(Database.contains(TI));
   auto &Record = Database.getTypeRecord(TI);
-  CVTypeVisitor V(Callbacks);
-  return V.visitTypeRecord(Record, TI);
+  return codeview::visitTypeRecord(Record, TI, Callbacks);
 }
 
 Error RandomAccessTypeVisitor::visitRangeForType(TypeIndex TI) {
@@ -78,7 +76,7 @@ Error RandomAccessTypeVisitor::visitRange(TypeIndex Begin, uint32_t BeginOffset,
 
   while (Begin != End) {
     assert(!Database.contains(Begin));
-    if (auto EC = InternalVisitor.visitTypeRecord(*RI, Begin))
+    if (auto EC = codeview::visitTypeRecord(*RI, Begin, DatabaseVisitor))
       return EC;
     KnownOffsets[Begin.toArrayIndex()] = BeginOffset;
 

lib/DebugInfo/CodeView/TypeDumpVisitor.cpp

@@ -216,8 +216,7 @@ Error TypeDumpVisitor::visitMemberEnd(CVMemberRecord &Record) {
 
 Error TypeDumpVisitor::visitKnownRecord(CVType &CVR,
                                         FieldListRecord &FieldList) {
-  CVTypeVisitor Visitor(*this);
-  if (auto EC = Visitor.visitFieldListMemberStream(FieldList.Data))
+  if (auto EC = codeview::visitMemberRecordStream(FieldList.Data, *this))
     return EC;
 
   return Error::success();

lib/DebugInfo/CodeView/TypeStreamMerger.cpp

@@ -361,8 +361,7 @@ Error TypeStreamMerger::visitKnownRecord(CVType &, FieldListRecord &R) {
   // Visit the members inside the field list.
   HadUntranslatedMember = false;
   FieldListBuilder.begin();
-  CVTypeVisitor Visitor(*this);
-  if (auto EC = Visitor.visitFieldListMemberStream(R.Data))
+  if (auto EC = codeview::visitMemberRecordStream(R.Data, *this))
     return EC;
 
   // Write the record if we translated all field list members.
@@ -440,18 +439,9 @@ Error TypeStreamMerger::visitUnknownType(CVType &Rec) {
 
 Error TypeStreamMerger::mergeStream(const CVTypeArray &Types) {
   assert(IndexMap.empty());
-  TypeVisitorCallbackPipeline Pipeline;
   LastError = Error::success();
 
-  TypeDeserializer Deserializer;
-  Pipeline.addCallbackToPipeline(Deserializer);
-  Pipeline.addCallbackToPipeline(*this);
-
-  CVTypeVisitor Visitor(Pipeline);
-  if (Handler)
-    Visitor.addTypeServerHandler(*Handler);
-
-  if (auto EC = Visitor.visitTypeStream(Types))
+  if (auto EC = codeview::visitTypeStream(Types, *this, Handler))
     return EC;
 
   // If we found bad indices but no other errors, try doing another pass and see
@@ -466,7 +456,8 @@ Error TypeStreamMerger::mergeStream(const CVTypeArray &Types) {
     IsSecondPass = true;
     NumBadIndices = 0;
     CurIndex = TypeIndex(TypeIndex::FirstNonSimpleIndex);
-    if (auto EC = Visitor.visitTypeStream(Types))
+
+    if (auto EC = codeview::visitTypeStream(Types, *this, Handler))
       return EC;
 
     assert(NumBadIndices <= BadIndicesRemaining &&

lib/DebugInfo/PDB/Native/PDBTypeServerHandler.cpp

@@ -55,9 +55,8 @@ PDBTypeServerHandler::handleInternal(PDBFile &File,
   auto ExpectedTpi = File.getPDBTpiStream();
   if (!ExpectedTpi)
     return ExpectedTpi.takeError();
-  CVTypeVisitor Visitor(Callbacks);
 
-  if (auto EC = Visitor.visitTypeStream(ExpectedTpi->types(nullptr)))
+  if (auto EC = codeview::visitTypeStream(ExpectedTpi->typeArray(), Callbacks))
     return std::move(EC);
 
   return true;