[lld] r358979 - [ELF] Change findOrphanPos to only consider live sections

[Andrew Ng via llvm-commits]

Author: anng
Date: Tue Apr 23 05:17:15 2019
New Revision: 358979

URL: http://llvm.org/viewvc/llvm-project?rev=358979&view=rev
Log:
[ELF] Change findOrphanPos to only consider live sections

This patch changes the behaviour of findOrphanPos to only consider live
sections when placing orphan sections. This used to be how it behaved in
the past.

Differential Revision: https://reviews.llvm.org/D60273

Modified:
    lld/trunk/ELF/Writer.cpp

Modified: lld/trunk/ELF/Writer.cpp
URL: http://llvm.org/viewvc/llvm-project/lld/trunk/ELF/Writer.cpp?rev=358979&r1=358978&r2=358979&view=diff
==============================================================================
--- lld/trunk/ELF/Writer.cpp (original)
+++ lld/trunk/ELF/Writer.cpp Tue Apr 23 05:17:15 2019
@@ -1094,16 +1094,19 @@ findOrphanPos(std::vector<BaseCommand *>
   int Proximity = getRankProximity(Sec, *I);
   for (; I != E; ++I) {
     auto *CurSec = dyn_cast<OutputSection>(*I);
-    if (!CurSec)
+    if (!CurSec || !CurSec->Live)
       continue;
     if (getRankProximity(Sec, CurSec) != Proximity ||
         Sec->SortRank < CurSec->SortRank)
       break;
   }
 
-  auto IsOutputSec = [](BaseCommand *Cmd) { return isa<OutputSection>(Cmd); };
+  auto IsLiveOutputSec = [](BaseCommand *Cmd) {
+    auto *OS = dyn_cast<OutputSection>(Cmd);
+    return OS && OS->Live;
+  };
   auto J = std::find_if(llvm::make_reverse_iterator(I),
-                        llvm::make_reverse_iterator(B), IsOutputSec);
+                        llvm::make_reverse_iterator(B), IsLiveOutputSec);
   I = J.base();
 
   // As a special case, if the orphan section is the last section, put
@@ -1111,7 +1114,7 @@ findOrphanPos(std::vector<BaseCommand *>
   // This matches bfd's behavior and is convenient when the linker script fully
   // specifies the start of the file, but doesn't care about the end (the non
   // alloc sections for example).
-  auto NextSec = std::find_if(I, E, IsOutputSec);
+  auto NextSec = std::find_if(I, E, IsLiveOutputSec);
   if (NextSec == E)
     return E;