[lld] r294592 - Handle gcing user created metadata.

[Rafael Espindola via llvm-commits]

Author: rafael
Date: Thu Feb  9 09:17:56 2017
New Revision: 294592

URL: http://llvm.org/viewvc/llvm-project?rev=294592&view=rev
Log:
Handle gcing user created metadata.

In particular, this should allow us to gc unused asan metadata.

Added:
    lld/trunk/test/ELF/gc-sections-metadata.s
Modified:
    lld/trunk/ELF/MarkLive.cpp

Modified: lld/trunk/ELF/MarkLive.cpp
URL: http://llvm.org/viewvc/llvm-project/lld/trunk/ELF/MarkLive.cpp?rev=294592&r1=294591&r2=294592&view=diff
==============================================================================
--- lld/trunk/ELF/MarkLive.cpp (original)
+++ lld/trunk/ELF/MarkLive.cpp Thu Feb  9 09:17:56 2017
@@ -167,6 +167,9 @@ template <class ELFT> static bool isRese
   case SHT_PREINIT_ARRAY:
     return true;
   default:
+    if (Sec->Flags & SHF_LINK_ORDER)
+      return false;
+
     if (!(Sec->Flags & SHF_ALLOC))
       return true;
 

Added: lld/trunk/test/ELF/gc-sections-metadata.s
URL: http://llvm.org/viewvc/llvm-project/lld/trunk/test/ELF/gc-sections-metadata.s?rev=294592&view=auto
==============================================================================
--- lld/trunk/test/ELF/gc-sections-metadata.s (added)
+++ lld/trunk/test/ELF/gc-sections-metadata.s Thu Feb  9 09:17:56 2017
@@ -0,0 +1,38 @@
+# REQUIRES: x86
+
+# RUN: llvm-mc -filetype=obj -triple=x86_64-pc-linux %s -o %t.o
+# RUN: ld.lld --gc-sections %t.o -o %t
+# RUN: llvm-objdump -section-headers %t | FileCheck  %s
+
+# CHECK:      1 .foo1
+# CHECK-NEXT:   bar1
+# CHECK-NEXT:   .zed1
+# CHECK-NEXT:   .text
+# CHECK-NEXT:   .comment
+# CHECK-NEXT:   .symtab
+# CHECK-NEXT:   .shstrtab
+# CHECK-NEXT:   .strtab
+
+.global _start
+_start:
+.quad .foo1
+
+.section .foo1,"a"
+.quad 0
+
+.section .foo2,"a"
+.quad 0
+
+.section bar1,"am", at progbits,.foo1
+.quad .zed1
+.quad .foo1
+
+.section bar2,"am", at progbits,.foo2
+.quad .zed2
+.quad .foo2
+
+.section .zed1,"a"
+.quad 0
+
+.section .zed2,"a"
+.quad 0