[DWARF} Use LLVM's debug line parser in LLDB.

The line number table header was substantially revised in DWARF 5 and is
not fully supported by LLDB's current debug line implementation.

This patch replaces the LLDB debug line parser with its counterpart in
LLVM. This was possible because of the limited contact surface between
the code to parse the DWARF debug line section and the rest of LLDB.

We pay a small cost in terms of performance and memory usage. This is
something we plan to address in the near future.

Differential revision: https://reviews.llvm.org/D62570

llvm-svn: 368742

lldb/include/lldb/Core/FileSpecList.h

@@ -25,6 +25,9 @@ class Stream;
 /// A class that contains a mutable list of FileSpec objects.
 class FileSpecList {
 public:
+  typedef std::vector<FileSpec> collection;
+  typedef collection::const_iterator const_iterator;
+
   /// Default constructor.
   ///
   /// Initialize this object with an empty file list.
@@ -191,9 +194,10 @@ class FileSpecList {
   static size_t GetFilesMatchingPartialPath(const char *path, bool dir_okay,
                                             FileSpecList &matches);
 
+  const_iterator begin() const { return m_files.begin(); }
+  const_iterator end() const { return m_files.end(); }
+
 protected:
-  typedef std::vector<FileSpec>
-      collection;     ///< The collection type for the file list.
   collection m_files; ///< A collection of FileSpec objects.
 };
 

lldb/include/lldb/Symbol/CompileUnit.h

@@ -298,6 +298,8 @@ class CompileUnit : public std::enable_shared_from_this<CompileUnit>,
   ///     A line table object pointer that this object now owns.
   void SetLineTable(LineTable *line_table);
 
+  void SetSupportFiles(const FileSpecList &support_files);
+
   void SetDebugMacros(const DebugMacrosSP &debug_macros);
 
   /// Set accessor for the variable list.

lldb/source/Plugins/SymbolFile/DWARF/CMakeLists.txt

@@ -22,7 +22,6 @@ add_lldb_library(lldbPluginSymbolFileDWARF PLUGIN
   DWARFDebugArangeSet.cpp
   DWARFDebugInfo.cpp
   DWARFDebugInfoEntry.cpp
-  DWARFDebugLine.cpp
   DWARFDebugMacro.cpp
   DWARFDebugRanges.cpp
   DWARFDeclContext.cpp