DWARF v5: fix directory index in the line table

Summary:
Prior to DWARF v5, a directory index of 0 represents DW_AT_comp_dir.

In DWARF v5, the index starts with 0 and Entry.DirIdx is the index into
Prologue.IncludeDirectories.

Reviewed By: labath

Differential Revision: https://reviews.llvm.org/D61253

llvm-svn: 360015

1 files changed, 16 insertions, 12 deletions

diff --git a/llvm/lib/DebugInfo/DWARF/DWARFDebugLine.cpp b/llvm/lib/DebugInfo/DWARF/DWARFDebugLine.cpp
index 1f18973f1d4..9f9aaabf1e8 100644
--- a/llvm/lib/DebugInfo/DWARF/DWARFDebugLine.cpp
+++ b/llvm/lib/DebugInfo/DWARF/DWARFDebugLine.cpp
@@ -1020,20 +1020,24 @@ bool DWARFDebugLine::LineTable::getFileNameByIndex(uint64_t FileIndex,
   }
 
   SmallString<16> FilePath;
-  uint64_t IncludeDirIndex = Entry.DirIdx;
   StringRef IncludeDir;
   // Be defensive about the contents of Entry.
-  if (IncludeDirIndex > 0 &&
-      IncludeDirIndex <= Prologue.IncludeDirectories.size())
-    IncludeDir = Prologue.IncludeDirectories[IncludeDirIndex - 1]
-                     .getAsCString()
-                     .getValue();
-
-  // We may still need to append compilation directory of compile unit.
-  // We know that FileName is not absolute, the only way to have an
-  // absolute path at this point would be if IncludeDir is absolute.
-  if (CompDir && !isPathAbsoluteOnWindowsOrPosix(IncludeDir))
-    sys::path::append(FilePath, CompDir);
+  if (Prologue.getVersion() >= 5) {
+    if (Entry.DirIdx < Prologue.IncludeDirectories.size())
+      IncludeDir =
+          Prologue.IncludeDirectories[Entry.DirIdx].getAsCString().getValue();
+  } else {
+    if (0 < Entry.DirIdx && Entry.DirIdx <= Prologue.IncludeDirectories.size())
+      IncludeDir = Prologue.IncludeDirectories[Entry.DirIdx - 1]
+                       .getAsCString()
+                       .getValue();
+
+    // We may still need to append compilation directory of compile unit.
+    // We know that FileName is not absolute, the only way to have an
+    // absolute path at this point would be if IncludeDir is absolute.
+    if (CompDir && !isPathAbsoluteOnWindowsOrPosix(IncludeDir))
+      sys::path::append(FilePath, CompDir);
+  }
 
   // sys::path::append skips empty strings.
   sys::path::append(FilePath, IncludeDir, FileName);