[llvm] r346786 - [NativePDB] Improved support for nested type reconstruction.

[Zachary Turner via llvm-commits]

Author: zturner
Date: Tue Nov 13 12:07:32 2018
New Revision: 346786

URL: http://llvm.org/viewvc/llvm-project?rev=346786&view=rev
Log:
[NativePDB] Improved support for nested type reconstruction.

In a previous patch, we pre-processed the TPI stream in order to build
the reverse mapping from nested type -> parent type so that we could
accurately reconstruct a DeclContext hierarchy.

However, there were some issues. An LF_NESTTYPE record is really just a
typedef, so although it happens to be used to indicate the name of the
nested type and referring to the global record which defines the type,
it is also used for every other kind of nested typedef. When we rebuild
the DeclContext hierarchy, we want it to be as accurate as possible,
which means that if we have something like:

  struct A {
    struct B {};
    using C = B;
  };

We don't want to create two CXXRecordDecls in the AST each with the
exact same definition. We just want to create one for B and then
define C as an alias to B. Previously, however, it would not be able
to distinguish between the two cases and it would treat A::B and
A::C as being two classes each with separate definitions. We address
the first half of improving the pre-processing logic so that only
actual definitions are treated this way.

Later, in a followup patch, we can handle the case of nested
typedefs since we're already going to be enumerating the field list
anyway and this patch introduces the general framework for
distinguishing between the two cases.

Differential Revision: https://reviews.llvm.org/D54357

Modified:
    llvm/trunk/lib/DebugInfo/CodeView/LazyRandomTypeCollection.cpp
    llvm/trunk/lib/DebugInfo/PDB/Native/TpiStream.cpp

Modified: llvm/trunk/lib/DebugInfo/CodeView/LazyRandomTypeCollection.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/DebugInfo/CodeView/LazyRandomTypeCollection.cpp?rev=346786&r1=346785&r2=346786&view=diff
==============================================================================
--- llvm/trunk/lib/DebugInfo/CodeView/LazyRandomTypeCollection.cpp (original)
+++ llvm/trunk/lib/DebugInfo/CodeView/LazyRandomTypeCollection.cpp Tue Nov 13 12:07:32 2018
@@ -89,6 +89,8 @@ uint32_t LazyRandomTypeCollection::getOf
 }
 
 CVType LazyRandomTypeCollection::getType(TypeIndex Index) {
+  assert(!Index.isSimple());
+
   auto EC = ensureTypeExists(Index);
   error(std::move(EC));
   assert(contains(Index));
@@ -97,6 +99,9 @@ CVType LazyRandomTypeCollection::getType
 }
 
 Optional<CVType> LazyRandomTypeCollection::tryGetType(TypeIndex Index) {
+  if (Index.isSimple())
+    return None;
+
   if (auto EC = ensureTypeExists(Index)) {
     consumeError(std::move(EC));
     return None;
@@ -151,6 +156,7 @@ Error LazyRandomTypeCollection::ensureTy
 }
 
 void LazyRandomTypeCollection::ensureCapacityFor(TypeIndex Index) {
+  assert(!Index.isSimple());
   uint32_t MinSize = Index.toArrayIndex() + 1;
 
   if (MinSize <= capacity())
@@ -163,6 +169,7 @@ void LazyRandomTypeCollection::ensureCap
 }
 
 Error LazyRandomTypeCollection::visitRangeForType(TypeIndex TI) {
+  assert(!TI.isSimple());
   if (PartialOffsets.empty())
     return fullScanForType(TI);
 
@@ -217,6 +224,7 @@ Optional<TypeIndex> LazyRandomTypeCollec
 }
 
 Error LazyRandomTypeCollection::fullScanForType(TypeIndex TI) {
+  assert(!TI.isSimple());
   assert(PartialOffsets.empty());
 
   TypeIndex CurrentTI = TypeIndex::fromArrayIndex(0);

Modified: llvm/trunk/lib/DebugInfo/PDB/Native/TpiStream.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/DebugInfo/PDB/Native/TpiStream.cpp?rev=346786&r1=346785&r2=346786&view=diff
==============================================================================
--- llvm/trunk/lib/DebugInfo/PDB/Native/TpiStream.cpp (original)
+++ llvm/trunk/lib/DebugInfo/PDB/Native/TpiStream.cpp Tue Nov 13 12:07:32 2018
@@ -215,6 +215,7 @@ TpiStream::findFullDeclForForwardRef(Typ
 }
 
 codeview::CVType TpiStream::getType(codeview::TypeIndex Index) {
+  assert(!Index.isSimple());
   return Types->getType(Index);
 }