[lldb][NativePDB] Fix crash in debugger when PDB has bad type index value

Fix crash when an inline site record in the PDB file contains type
index which is out of bounds

Author: gv

lldb/source/Plugins/SymbolFile/NativePDB/SymbolFileNativePDB.cpp

@@ -1719,19 +1719,23 @@ void SymbolFileNativePDB::ParseInlineSite(PdbCompilandSymId id,
   }
 
   // Get the inlined function name.
-  CVType inlinee_cvt = m_index->ipi().getType(inline_site.Inlinee);
   std::string inlinee_name;
-  if (inlinee_cvt.kind() == LF_MFUNC_ID) {
+  llvm::Expected<CVType> inlinee_cvt =
+      m_index->ipi().typeCollection().getTypeOrError(inline_site.Inlinee);
+  if (!inlinee_cvt) {
+    inlinee_name = "[error reading function name: " +
+                   llvm::toString(inlinee_cvt.takeError()) + "]";
+  } else if (inlinee_cvt->kind() == LF_MFUNC_ID) {
     MemberFuncIdRecord mfr;
     cantFail(
-        TypeDeserializer::deserializeAs<MemberFuncIdRecord>(inlinee_cvt, mfr));
+        TypeDeserializer::deserializeAs<MemberFuncIdRecord>(*inlinee_cvt, mfr));
     LazyRandomTypeCollection &types = m_index->tpi().typeCollection();
     inlinee_name.append(std::string(types.getTypeName(mfr.ClassType)));
     inlinee_name.append("::");
     inlinee_name.append(mfr.getName().str());
-  } else if (inlinee_cvt.kind() == LF_FUNC_ID) {
+  } else if (inlinee_cvt->kind() == LF_FUNC_ID) {
     FuncIdRecord fir;
-    cantFail(TypeDeserializer::deserializeAs<FuncIdRecord>(inlinee_cvt, fir));
+    cantFail(TypeDeserializer::deserializeAs<FuncIdRecord>(*inlinee_cvt, fir));
     TypeIndex parent_idx = fir.getParentScope();
     if (!parent_idx.isNoneType()) {
       LazyRandomTypeCollection &ids = m_index->ipi().typeCollection();

llvm/include/llvm/DebugInfo/CodeView/LazyRandomTypeCollection.h

@@ -70,7 +70,7 @@ class LLVM_ABI LazyRandomTypeCollection : public TypeCollection {
   uint32_t getOffsetOfType(TypeIndex Index);
 
   std::optional<CVType> tryGetType(TypeIndex Index);
-
+  llvm::Expected<CVType> getTypeOrError(TypeIndex Index);
   CVType getType(TypeIndex Index) override;
   StringRef getTypeName(TypeIndex Index) override;
   bool contains(TypeIndex Index) override;

llvm/lib/DebugInfo/CodeView/LazyRandomTypeCollection.cpp

@@ -93,20 +93,28 @@ CVType LazyRandomTypeCollection::getType(TypeIndex Index) {
   return Records[Index.toArrayIndex()].Type;
 }
 
-std::optional<CVType> LazyRandomTypeCollection::tryGetType(TypeIndex Index) {
+llvm::Expected<CVType>
+LazyRandomTypeCollection::getTypeOrError(TypeIndex Index) {
   if (Index.isSimple())
-    return std::nullopt;
+    return llvm::createStringError("Type index too low (%d)", Index.getIndex());
 
   if (auto EC = ensureTypeExists(Index)) {
-    consumeError(std::move(EC));
-    return std::nullopt;
+    return EC;
   }
 
   if (!contains(Index))
-    return std::nullopt;
+    return llvm::createStringError("Type index too high (%d)",
+                                   Index.getIndex());
   return Records[Index.toArrayIndex()].Type;
 }
 
+std::optional<CVType> LazyRandomTypeCollection::tryGetType(TypeIndex Index) {
+  llvm::Expected<CVType> res = getTypeOrError(Index);
+  if (!res)
+    return std::nullopt;
+  return *res;
+}
+
 StringRef LazyRandomTypeCollection::getTypeName(TypeIndex Index) {
   if (Index.isNoneType() || Index.isSimple())
     return TypeIndex::simpleTypeName(Index);