1 files changed, 35 insertions, 2 deletions
diff --git a/llvm/lib/DebugInfo/DWARF/DWARFDataExtractor.cpp b/llvm/lib/DebugInfo/DWARF/DWARFDataExtractor.cpp
index 53e676bc7031..886fe1dff976 100644
--- a/llvm/lib/DebugInfo/DWARF/DWARFDataExtractor.cpp
+++ b/llvm/lib/DebugInfo/DWARF/DWARFDataExtractor.cpp
@@ -7,11 +7,42 @@
 //===----------------------------------------------------------------------===//
 
 #include "llvm/DebugInfo/DWARF/DWARFDataExtractor.h"
-#include "llvm/BinaryFormat/Dwarf.h"
 #include "llvm/DebugInfo/DWARF/DWARFContext.h"
 
 using namespace llvm;
 
+std::pair<uint64_t, dwarf::DwarfFormat>
+DWARFDataExtractor::getInitialLength(uint64_t *Off, Error *Err) const {
+  ErrorAsOutParameter ErrAsOut(Err);
+  if (Err && *Err)
+    return {0, dwarf::DWARF32};
+
+  Cursor C(*Off);
+  uint64_t Length = getRelocatedValue(C, 4);
+  dwarf::DwarfFormat Format = dwarf::DWARF32;
+  if (Length == dwarf::DW_LENGTH_DWARF64) {
+    Length = getRelocatedValue(C, 8);
+    Format = dwarf::DWARF64;
+  } else if (Length >= dwarf::DW_LENGTH_lo_reserved) {
+    cantFail(C.takeError());
+    if (Err)
+      *Err = createStringError(
+          errc::invalid_argument,
+          "unsupported reserved unit length of value 0x%8.8" PRIx64, Length);
+    return {0, dwarf::DWARF32};
+  }
+
+  if (C) {
+    *Off = C.tell();
+    return {Length, Format};
+  }
+  if (Err)
+    *Err = C.takeError();
+  else
+    consumeError(C.takeError());
+  return {0, dwarf::DWARF32};
+}
+
 uint64_t DWARFDataExtractor::getRelocatedValue(uint32_t Size, uint64_t *Off,
                                                uint64_t *SecNdx,
                                                Error *Err) const {
@@ -19,9 +50,11 @@ uint64_t DWARFDataExtractor::getRelocatedValue(uint32_t Size, uint64_t *Off,
     *SecNdx = object::SectionedAddress::UndefSection;
   if (!Section)
     return getUnsigned(Off, Size, Err);
+
+  ErrorAsOutParameter ErrAsOut(Err);
   Optional<RelocAddrEntry> E = Obj->find(*Section, *Off);
   uint64_t A = getUnsigned(Off, Size, Err);
-  if (!E)
+  if (!E || (Err && *Err))
     return A;
   if (SecNdx)
     *SecNdx = E->SectionIndex;