[DEBUGINFO] Add flag -no-dwarf-pub-sections to disable pub sections.

Summary:
Added a flag -no-dwarf-pub-sections, which allows to disable
emission of DWARF public sections.

Reviewers: probinson, echristo

Subscribers: aprantl, JDevlieghere, llvm-commits

Differential Revision: https://reviews.llvm.org/D44385

llvm-svn: 327994
diff --git a/llvm/lib/CodeGen/AsmPrinter/DwarfDebug.h b/llvm/lib/CodeGen/AsmPrinter/DwarfDebug.h
index c8a36ba..56a1d63 100644
--- a/llvm/lib/CodeGen/AsmPrinter/DwarfDebug.h
+++ b/llvm/lib/CodeGen/AsmPrinter/DwarfDebug.h
@@ -258,6 +258,9 @@
   /// Use inlined strings.
   bool UseInlineStrings = false;
 
+  /// Whether to emit DWARF pub sections or not.
+  bool UsePubSections = true;
+
   /// DWARF5 Experimental Options
   /// @{
   bool HasDwarfAccelTables;
@@ -501,6 +504,9 @@
   /// Returns whether to use inline strings.
   bool useInlineStrings() const { return UseInlineStrings; }
 
+  /// Returns whether GNU oub sections should be emitted.
+  bool usePubSections() const { return UsePubSections; }
+
   // Experimental DWARF5 features.
 
   /// Returns whether or not to emit tables that dwarf consumers can