[lld] r282847 - Fix another --gc-sections crash.

[Rafael Espindola via llvm-commits]

Author: rafael
Date: Fri Sep 30 01:48:09 2016
New Revision: 282847

URL: http://llvm.org/viewvc/llvm-project?rev=282847&view=rev
Log:
Fix another --gc-sections crash.

The missing case was when a merge section was only referenced from
non-alloca sections.

Modified:
    lld/trunk/ELF/InputSection.cpp
    lld/trunk/test/ELF/gc-sections-non-alloc-to-merge.s

Modified: lld/trunk/ELF/InputSection.cpp
URL: http://llvm.org/viewvc/llvm-project/lld/trunk/ELF/InputSection.cpp?rev=282847&r1=282846&r2=282847&view=diff
==============================================================================
--- lld/trunk/ELF/InputSection.cpp (original)
+++ lld/trunk/ELF/InputSection.cpp Fri Sep 30 01:48:09 2016
@@ -620,6 +620,9 @@ typename ELFT::uint MergeInputSection<EL
   if (It != OffsetMap.end())
     return It->second;
 
+  if (!this->Live)
+    return 0;
+
   // If Offset is not at beginning of a section piece, it is not in the map.
   // In that case we need to search from the original section piece vector.
   const SectionPiece &Piece = *this->getSectionPiece(Offset);

Modified: lld/trunk/test/ELF/gc-sections-non-alloc-to-merge.s
URL: http://llvm.org/viewvc/llvm-project/lld/trunk/test/ELF/gc-sections-non-alloc-to-merge.s?rev=282847&r1=282846&r2=282847&view=diff
==============================================================================
--- lld/trunk/test/ELF/gc-sections-non-alloc-to-merge.s (original)
+++ lld/trunk/test/ELF/gc-sections-non-alloc-to-merge.s Fri Sep 30 01:48:09 2016
@@ -17,5 +17,11 @@ _start:
 .Lbar:
         .long 2
 
+        .section        .merge2,"aM", at progbits,4
+        .p2align        2
+.Lzed:
+        .long 1
+
         .section bar
         .quad .Lbar
+	.quad .Lzed