DWARF: Add basic support for line tables.

The llvm-dwarfdump output isn't very verbose yet.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@139771 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/DebugInfo/DWARFContext.cpp b/lib/DebugInfo/DWARFContext.cpp
index 3359ae3..68f58d9 100644
--- a/lib/DebugInfo/DWARFContext.cpp
+++ b/lib/DebugInfo/DWARFContext.cpp
@@ -25,6 +25,10 @@
   DWARFDebugArangeSet set;
   while (set.extract(arangesData, &offset))
     set.dump(OS);
+
+  OS << "\n.debug_lines contents:\n";
+  DataExtractor lineData(getLineSection(), isLittleEndian(), 8);
+  DWARFDebugLine::dump(lineData, OS);
 }
 
 const DWARFDebugAbbrev *DWARFContext::getDebugAbbrev() {
@@ -51,6 +55,17 @@
   return Aranges.get();
 }
 
+const DWARFDebugLine *DWARFContext::getDebugLine() {
+  if (Line)
+    return Line.get();
+
+  DataExtractor lineData(getLineSection(), isLittleEndian(), 0);
+
+  Line.reset(new DWARFDebugLine());
+  Line->parse(lineData);
+  return Line.get();
+}
+
 void DWARFContext::parseCompileUnits() {
   uint32_t offset = 0;
   const DataExtractor &debug_info_data = DataExtractor(getInfoSection(),