[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

llvm/test/tools/llvm-objcopy/strip-debug.test

@@ -67,7 +67,7 @@
 # RUN: llvm-objcopy --strip-debug %t.thin.a %t2.thin.a
 # RUN: cat %t.thin.a | FileCheck %s --check-prefix=VERIFY-THIN-ARCHIVE
 # RUN: cat %t2.thin.a | FileCheck %s --check-prefix=VERIFY-THIN-ARCHIVE
- 
+
 # VERIFY-THIN-ARCHIVE: !<thin>
 
 # Verify that the member of a thin archive was properly modified.
@@ -94,6 +94,12 @@ Sections:
   - Name:            .debugfoo
     Type:            SHT_PROGBITS
     Content:         "00000000"
+  - Name:            .zdebugfoo
+    Type:            SHT_PROGBITS
+    Content:         "00000000"
+  - Name:            .gdb_index
+    Type:            SHT_PROGBITS
+    Content:         "00000000"
   - Name:            .text
     Type:            SHT_PROGBITS
     Flags:           [ SHF_ALLOC, SHF_EXECINSTR ]

llvm/tools/llvm-objcopy/llvm-objcopy.cpp

@@ -186,7 +186,8 @@ LLVM_ATTRIBUTE_NORETURN void reportError(StringRef File, Error E) {
 } // 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) {