[CodeView] Provide a common interface for type collections.

Right now we have multiple notions of things that represent collections of
types. Most commonly used are TypeDatabase, which is supposed to keep
mappings from TypeIndex to type name when reading a type stream, which
happens when reading PDBs. And also TypeTableBuilder, which is used to
build up a collection of types dynamically which we will later serialize
(i.e. when writing PDBs).

But often you just want to do some operation on a collection of types, and
you may want to do the same operation on any kind of collection. For
example, you might want to merge two TypeTableBuilders or you might want
to merge two type streams that you loaded from various files.

This dichotomy between reading and writing is responsible for a lot of the
existing code duplication and overlapping responsibilities in the existing
CodeView library classes. For example, after building up a
TypeTableBuilder with a bunch of type records, if we want to dump it we
have to re-invent a bunch of extra glue because our dumper takes a
TypeDatabase or a CVTypeArray, which are both incompatible with
TypeTableBuilder.

This patch introduces an abstract base class called TypeCollection which
is shared between the various type collection like things. Wherever we
previously stored a TypeDatabase& in some common class, we now store a
TypeCollection&.

The advantage of this is that all the details of how the collection are
implemented, such as lazy deserialization of partial type streams, is
completely transparent and you can just treat any collection of types the
same regardless of where it came from.

Differential Revision: https://reviews.llvm.org/D33293

llvm-svn: 303388

1 files changed, 12 insertions, 28 deletions

diff --git a/llvm/lib/CodeGen/AsmPrinter/CodeViewDebug.cpp b/llvm/lib/CodeGen/AsmPrinter/CodeViewDebug.cpp
index 7d945690e9c..7c2a7695718 100644
--- a/llvm/lib/CodeGen/AsmPrinter/CodeViewDebug.cpp
+++ b/llvm/lib/CodeGen/AsmPrinter/CodeViewDebug.cpp
@@ -13,7 +13,6 @@
 
 #include "CodeViewDebug.h"
 #include "llvm/ADT/TinyPtrVector.h"
-#include "llvm/DebugInfo/CodeView/CVTypeDumper.h"
 #include "llvm/DebugInfo/CodeView/CVTypeVisitor.h"
 #include "llvm/DebugInfo/CodeView/CodeView.h"
 #include "llvm/DebugInfo/CodeView/Line.h"
@@ -23,6 +22,7 @@
 #include "llvm/DebugInfo/CodeView/TypeDumpVisitor.h"
 #include "llvm/DebugInfo/CodeView/TypeIndex.h"
 #include "llvm/DebugInfo/CodeView/TypeRecord.h"
+#include "llvm/DebugInfo/CodeView/TypeTableCollection.h"
 #include "llvm/DebugInfo/CodeView/TypeVisitorCallbacks.h"
 #include "llvm/IR/Constants.h"
 #include "llvm/MC/MCAsmInfo.h"
@@ -469,17 +469,21 @@ void CodeViewDebug::emitTypeInformation() {
     CommentPrefix += ' ';
   }
 
-  TypeDatabase TypeDB(TypeTable.records().size());
-  CVTypeDumper CVTD(TypeDB);
-  TypeTable.ForEachRecord([&](TypeIndex Index, ArrayRef<uint8_t> Record) {
+  TypeTableCollection Table(TypeTable.records());
+  Optional<TypeIndex> B = Table.getFirst();
+  do {
+    // This will fail if the record data is invalid.
+    CVType Record = Table.getType(*B);
+
     if (OS.isVerboseAsm()) {
       // Emit a block comment describing the type record for readability.
       SmallString<512> CommentBlock;
       raw_svector_ostream CommentOS(CommentBlock);
       ScopedPrinter SP(CommentOS);
       SP.setPrefix(CommentPrefix);
-      TypeDumpVisitor TDV(TypeDB, &SP, false);
-      Error E = CVTD.dump(Record, TDV);
+      TypeDumpVisitor TDV(Table, &SP, false);
+
+      Error E = codeview::visitTypeRecord(Record, *B, TDV);
       if (E) {
         logAllUnhandledErrors(std::move(E), errs(), "error: ");
         llvm_unreachable("produced malformed type record");
@@ -489,29 +493,9 @@ void CodeViewDebug::emitTypeInformation() {
       // newline.
       OS.emitRawComment(
           CommentOS.str().drop_front(CommentPrefix.size() - 1).rtrim());
-    } else {
-#ifndef NDEBUG
-      // Assert that the type data is valid even if we aren't dumping
-      // comments. The MSVC linker doesn't do much type record validation,
-      // so the first link of an invalid type record can succeed while
-      // subsequent links will fail with LNK1285.
-      BinaryByteStream Stream(Record, llvm::support::little);
-      CVTypeArray Types;
-      BinaryStreamReader Reader(Stream);
-      Error E = Reader.readArray(Types, Reader.getLength());
-      if (!E) {
-        TypeVisitorCallbacks C;
-        E = codeview::visitTypeStream(Types, C);
-      }
-      if (E) {
-        logAllUnhandledErrors(std::move(E), errs(), "error: ");
-        llvm_unreachable("produced malformed type record");
-      }
-#endif
     }
-    StringRef S(reinterpret_cast<const char *>(Record.data()), Record.size());
-    OS.EmitBinaryData(S);
-  });
+    OS.EmitBinaryData(Record.str_data());
+  } while (B = Table.getNext(*B));
 }
 
 namespace {