[lld] r264181 - [LTO] Keep linkonce symbols when required.

[Davide Italiano via llvm-commits]

Author: davide
Date: Wed Mar 23 13:41:48 2016
New Revision: 264181

URL: http://llvm.org/viewvc/llvm-project?rev=264181&view=rev
Log:
[LTO] Keep linkonce symbols when required.

Similarly to how we do with linkonce_odr symbols already, but
change their linkage to weak.

Added:
    lld/trunk/test/ELF/lto/Inputs/linkonce.ll
    lld/trunk/test/ELF/lto/linkonce.ll
Modified:
    lld/trunk/ELF/LTO.cpp

Modified: lld/trunk/ELF/LTO.cpp
URL: http://llvm.org/viewvc/llvm-project/lld/trunk/ELF/LTO.cpp?rev=264181&r1=264180&r2=264181&view=diff
==============================================================================
--- lld/trunk/ELF/LTO.cpp (original)
+++ lld/trunk/ELF/LTO.cpp Wed Mar 23 13:41:48 2016
@@ -85,8 +85,16 @@ void BitcodeCompiler::add(BitcodeFile &F
     if (!BitcodeFile::shouldSkip(Sym)) {
       if (SymbolBody *B = Bodies[BodyIndex++])
         if (&B->repl() == B && isa<DefinedBitcode>(B)) {
-          if (GV->getLinkage() == llvm::GlobalValue::LinkOnceODRLinkage)
+          switch (GV->getLinkage()) {
+          default:
+            break;
+          case llvm::GlobalValue::LinkOnceAnyLinkage:
+            GV->setLinkage(GlobalValue::WeakAnyLinkage);
+            break;
+          case llvm::GlobalValue::LinkOnceODRLinkage:
             GV->setLinkage(GlobalValue::WeakODRLinkage);
+            break;
+          }
           Keep.push_back(GV);
         }
     }

Added: lld/trunk/test/ELF/lto/Inputs/linkonce.ll
URL: http://llvm.org/viewvc/llvm-project/lld/trunk/test/ELF/lto/Inputs/linkonce.ll?rev=264181&view=auto
==============================================================================
--- lld/trunk/test/ELF/lto/Inputs/linkonce.ll (added)
+++ lld/trunk/test/ELF/lto/Inputs/linkonce.ll Wed Mar 23 13:41:48 2016
@@ -0,0 +1,6 @@
+target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
+target triple = "x86_64-unknown-linux-gnu"
+
+define linkonce void @f() {
+  ret void
+}

Added: lld/trunk/test/ELF/lto/linkonce.ll
URL: http://llvm.org/viewvc/llvm-project/lld/trunk/test/ELF/lto/linkonce.ll?rev=264181&view=auto
==============================================================================
--- lld/trunk/test/ELF/lto/linkonce.ll (added)
+++ lld/trunk/test/ELF/lto/linkonce.ll Wed Mar 23 13:41:48 2016
@@ -0,0 +1,17 @@
+; REQUIRES: x86
+; RUN: llvm-as %p/Inputs/linkonce.ll -o %t1.o
+; RUN: llc %s -o %t2.o -filetype=obj
+; RUN: ld.lld %t1.o %t2.o -o %t.so -shared -save-temps
+; RUN: llvm-dis %t.so.lto.opt.bc -o - | FileCheck %s
+
+target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
+target triple = "x86_64-unknown-linux-gnu"
+declare void @f()
+
+define void @g() {
+  call void @f()
+  ret void
+}
+
+; Be sure that 'f' is kept and has weak linkage.
+; CHECK: define weak void @f()