MC: Implement support for new .addrsig and .addrsig_sym directives.

Part of the address-significance tables proposal:
http://lists.llvm.org/pipermail/llvm-dev/2018-May/123514.html

Differential Revision: https://reviews.llvm.org/D47744

llvm-svn: 337328
diff --git a/llvm/tools/llvm-readobj/llvm-readobj.cpp b/llvm/tools/llvm-readobj/llvm-readobj.cpp
index 39567b8..5c8a880 100644
--- a/llvm/tools/llvm-readobj/llvm-readobj.cpp
+++ b/llvm/tools/llvm-readobj/llvm-readobj.cpp
@@ -302,6 +302,9 @@
 
   cl::opt<bool> CGProfile("elf-cg-profile", cl::desc("Display callgraph profile section"));
 
+  cl::opt<bool> Addrsig("elf-addrsig",
+                        cl::desc("Display address-significance table"));
+
   cl::opt<OutputStyleTy>
       Output("elf-output-style", cl::desc("Specify ELF dump style"),
              cl::values(clEnumVal(LLVM, "LLVM default style"),
@@ -469,6 +472,8 @@
       Dumper->printHashHistogram();
     if (opts::CGProfile)
       Dumper->printCGProfile();
+    if (opts::Addrsig)
+      Dumper->printAddrsig();
     if (opts::Notes)
       Dumper->printNotes();
   }