[PDB] Fix linking of function symbols and local variables.

The compiler outputs PROC32_ID symbols into the object files
for functions, and these symbols have an embedded type index
which, when copied to the PDB, refer to the IPI stream.  However,
the symbols themselves are also converted into regular symbols
(e.g. S_GPROC32_ID -> S_GPROC32), and type indices in the regular
symbol records refer to the TPI stream.  So this patch applies
two fixes to function records.
  1. It converts ID symbols to the proper non-ID record type.
  2. After remapping the type index from the object file's index
     space to the PDB file/IPI stream's index space, it then
     remaps that index to the TPI stream's index space by.

Besides functions, during the remapping process we were also
discarding symbol record types which we did not recognize.
In particular, we were discarding S_BPREL32 records, which is
what MSVC uses to describe local variables on the stack.  So
this patch fixes that as well by copying them to the PDB.

Differential Revision: https://reviews.llvm.org/D36426

llvm-svn: 310394

1 files changed, 39 insertions, 8 deletions

diff --git a/llvm/lib/DebugInfo/CodeView/TypeIndexDiscovery.cpp b/llvm/lib/DebugInfo/CodeView/TypeIndexDiscovery.cpp
index 0d935c4472a..650f1942b94 100644
--- a/llvm/lib/DebugInfo/CodeView/TypeIndexDiscovery.cpp
+++ b/llvm/lib/DebugInfo/CodeView/TypeIndexDiscovery.cpp
@@ -395,6 +395,7 @@ static bool discoverTypeIndices(ArrayRef<uint8_t> Content, SymbolKind Kind,
   case SymbolKind::S_CONSTANT:
     Refs.push_back({TiRefKind::TypeRef, 0, 1}); // Type
     break;
+  case SymbolKind::S_BPREL32:
   case SymbolKind::S_REGREL32:
     Refs.push_back({TiRefKind::TypeRef, 4, 1}); // Type
     break;
@@ -450,17 +451,17 @@ void llvm::codeview::discoverTypeIndices(const CVType &Type,
   ::discoverTypeIndices(Type.content(), Type.kind(), Refs);
 }
 
-void llvm::codeview::discoverTypeIndices(const CVType &Type,
-                                         SmallVectorImpl<TypeIndex> &Indices) {
-
+static void resolveTypeIndexReferences(ArrayRef<uint8_t> RecordData,
+                                       ArrayRef<TiReference> Refs,
+                                       SmallVectorImpl<TypeIndex> &Indices) {
   Indices.clear();
 
-  SmallVector<TiReference, 4> Refs;
-  discoverTypeIndices(Type, Refs);
   if (Refs.empty())
     return;
 
-  BinaryStreamReader Reader(Type.content(), support::little);
+  RecordData = RecordData.drop_front(sizeof(RecordPrefix));
+
+  BinaryStreamReader Reader(RecordData, support::little);
   for (const auto &Ref : Refs) {
     Reader.setOffset(Ref.Offset);
     FixedStreamArray<TypeIndex> Run;
@@ -469,6 +470,18 @@ void llvm::codeview::discoverTypeIndices(const CVType &Type,
   }
 }
 
+void llvm::codeview::discoverTypeIndices(const CVType &Type,
+                                         SmallVectorImpl<TypeIndex> &Indices) {
+  return discoverTypeIndices(Type.RecordData, Indices);
+}
+
+void llvm::codeview::discoverTypeIndices(ArrayRef<uint8_t> RecordData,
+                                         SmallVectorImpl<TypeIndex> &Indices) {
+  SmallVector<TiReference, 4> Refs;
+  discoverTypeIndices(RecordData, Refs);
+  resolveTypeIndexReferences(RecordData, Refs, Indices);
+}
+
 void llvm::codeview::discoverTypeIndices(ArrayRef<uint8_t> RecordData,
                                          SmallVectorImpl<TiReference> &Refs) {
   const RecordPrefix *P =
@@ -477,8 +490,26 @@ void llvm::codeview::discoverTypeIndices(ArrayRef<uint8_t> RecordData,
   ::discoverTypeIndices(RecordData.drop_front(sizeof(RecordPrefix)), K, Refs);
 }
 
-bool llvm::codeview::discoverTypeIndices(const CVSymbol &Sym,
-                                         SmallVectorImpl<TiReference> &Refs) {
+bool llvm::codeview::discoverTypeIndicesInSymbol(
+    const CVSymbol &Sym, SmallVectorImpl<TiReference> &Refs) {
   SymbolKind K = Sym.kind();
   return ::discoverTypeIndices(Sym.content(), K, Refs);
 }
+
+bool llvm::codeview::discoverTypeIndicesInSymbol(
+    ArrayRef<uint8_t> RecordData, SmallVectorImpl<TiReference> &Refs) {
+  const RecordPrefix *P =
+      reinterpret_cast<const RecordPrefix *>(RecordData.data());
+  SymbolKind K = static_cast<SymbolKind>(uint16_t(P->RecordKind));
+  return ::discoverTypeIndices(RecordData.drop_front(sizeof(RecordPrefix)), K,
+                               Refs);
+}
+
+bool llvm::codeview::discoverTypeIndicesInSymbol(
+    ArrayRef<uint8_t> RecordData, SmallVectorImpl<TypeIndex> &Indices) {
+  SmallVector<TiReference, 2> Refs;
+  if (!discoverTypeIndicesInSymbol(RecordData, Refs))
+    return false;
+  resolveTypeIndexReferences(RecordData, Refs, Indices);
+  return true;
+}