[llvm] r255169 - Synchronize the logic for deciding to link a gv.

[Rafael Espindola via llvm-commits]

Author: rafael
Date: Wed Dec  9 16:44:00 2015
New Revision: 255169

URL: http://llvm.org/viewvc/llvm-project?rev=255169&view=rev
Log:
Synchronize the logic for deciding to link a gv.

We were deciding to not link an available_externally gv over a
declaration, but then copying over the body anyway.

Added:
    llvm/trunk/test/Linker/Inputs/available_externally_over_decl.ll
    llvm/trunk/test/Linker/available_externally_over_decl.ll
Modified:
    llvm/trunk/lib/Linker/LinkModules.cpp

Modified: llvm/trunk/lib/Linker/LinkModules.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Linker/LinkModules.cpp?rev=255169&r1=255168&r2=255169&view=diff
==============================================================================
--- llvm/trunk/lib/Linker/LinkModules.cpp (original)
+++ llvm/trunk/lib/Linker/LinkModules.cpp Wed Dec  9 16:44:00 2015
@@ -1050,7 +1050,12 @@ bool ModuleLinker::shouldLinkFromSource(
       return false;
     }
     // If the Dest is weak, use the source linkage.
-    LinkFromSrc = Dest.hasExternalWeakLinkage();
+    if (Dest.hasExternalWeakLinkage()) {
+      LinkFromSrc = true;
+      return false;
+    }
+    // Link an available_externally over a declaration.
+    LinkFromSrc = !Src.isDeclaration() && Dest.isDeclaration();
     return false;
   }
 

Added: llvm/trunk/test/Linker/Inputs/available_externally_over_decl.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Linker/Inputs/available_externally_over_decl.ll?rev=255169&view=auto
==============================================================================
--- llvm/trunk/test/Linker/Inputs/available_externally_over_decl.ll (added)
+++ llvm/trunk/test/Linker/Inputs/available_externally_over_decl.ll Wed Dec  9 16:44:00 2015
@@ -0,0 +1,5 @@
+ at h = global void ()* @f
+
+define available_externally void @f() {
+  ret void
+}

Added: llvm/trunk/test/Linker/available_externally_over_decl.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Linker/available_externally_over_decl.ll?rev=255169&view=auto
==============================================================================
--- llvm/trunk/test/Linker/available_externally_over_decl.ll (added)
+++ llvm/trunk/test/Linker/available_externally_over_decl.ll Wed Dec  9 16:44:00 2015
@@ -0,0 +1,9 @@
+; RUN: llvm-link -S %s %p/Inputs/available_externally_over_decl.ll | FileCheck %s
+
+declare void @f()
+
+define void ()* @main() {
+  ret void ()* @f
+}
+
+; CHECK: define available_externally void @f() {