[DWARF parser] Fix nasty memory corruption in .dwo files handling.

Forge a test case where llvm-symbolizer has to use external .dwo
file to produce the inlining information.

llvm-svn: 217270

1 files changed, 9 insertions, 11 deletions

diff --git a/llvm/lib/DebugInfo/DWARFUnit.cpp b/llvm/lib/DebugInfo/DWARFUnit.cpp
index fe75ebe..2bb7933 100644
--- a/llvm/lib/DebugInfo/DWARFUnit.cpp
+++ b/llvm/lib/DebugInfo/DWARFUnit.cpp
@@ -235,11 +235,14 @@ size_t DWARFUnit::extractDIEsIfNeeded(bool CUDieOnly) {
   return DieArray.size();
 }
 
-DWARFUnit::DWOHolder::DWOHolder(std::unique_ptr<object::ObjectFile> DWOFile)
-    : DWOFile(std::move(DWOFile)),
-      DWOContext(
-          cast<DWARFContext>(DIContext::getDWARFContext(*this->DWOFile))),
-      DWOU(nullptr) {
+DWARFUnit::DWOHolder::DWOHolder(StringRef DWOPath)
+    : DWOFile(), DWOContext(), DWOU(nullptr) {
+  auto Obj = object::ObjectFile::createObjectFile(DWOPath);
+  if (!Obj)
+    return;
+  DWOFile = std::move(Obj.get());
+  DWOContext.reset(
+      cast<DWARFContext>(DIContext::getDWARFContext(*DWOFile.getBinary())));
   if (DWOContext->getNumDWOCompileUnits() > 0)
     DWOU = DWOContext->getDWOCompileUnitAtIndex(0);
 }
@@ -261,12 +264,7 @@ bool DWARFUnit::parseDWO() {
     sys::path::append(AbsolutePath, CompilationDir);
   }
   sys::path::append(AbsolutePath, DWOFileName);
-  ErrorOr<object::OwningBinary<object::ObjectFile>> DWOFile =
-      object::ObjectFile::createObjectFile(AbsolutePath);
-  if (!DWOFile)
-    return false;
-  // Reset DWOHolder.
-  DWO = llvm::make_unique<DWOHolder>(std::move(DWOFile->getBinary()));
+  DWO = llvm::make_unique<DWOHolder>(AbsolutePath);
   DWARFUnit *DWOCU = DWO->getUnit();
   // Verify that compile unit in .dwo file is valid.
   if (!DWOCU || DWOCU->getDWOId() != getDWOId()) {