[llvm-objcopy] Make --strip-debug strip .gdb_index

Summary:
See binutils-gdb/bfd/elf.c, GNU objcopy also strips .stab* (STABS)
.line* (DWARF 1) .gnu.linkonce.wi.* (linkonce section for .debug_info) but
I'm not sure we need to be compatible with it.

Reviewers: dblaikie, alexshap, jakehehrlich, jhenderson

Reviewed By: alexshap, jakehehrlich

Subscribers: aprantl, JDevlieghere, jakehehrlich, llvm-commits

Differential Revision: https://reviews.llvm.org/D50100

llvm-svn: 338443
diff --git a/llvm/tools/llvm-objcopy/llvm-objcopy.cpp b/llvm/tools/llvm-objcopy/llvm-objcopy.cpp
index e903e57..21a1622 100644
--- a/llvm/tools/llvm-objcopy/llvm-objcopy.cpp
+++ b/llvm/tools/llvm-objcopy/llvm-objcopy.cpp
@@ -186,7 +186,8 @@
 } // end namespace llvm
 
 static bool IsDebugSection(const SectionBase &Sec) {
-  return Sec.Name.startswith(".debug") || Sec.Name.startswith(".zdebug");
+  return Sec.Name.startswith(".debug") || Sec.Name.startswith(".zdebug") ||
+         Sec.Name == ".gdb_index";
 }
 
 static bool IsDWOSection(const SectionBase &Sec) {