Fix handling of extern_weak. This was broken by r225983.

llvm-svn: 226026

Author: espindola

llvm/test/tools/gold/emit-llvm.ll

@@ -21,6 +21,9 @@
 
 target triple = "x86_64-unknown-linux-gnu"
 
+@g7 = extern_weak global i32
+; CHECK-DAG: @g7 = extern_weak global i32
+
 ; CHECK: define internal void @f1()
 ; OPT-NOT: @f1
 define hidden void @f1() {
@@ -62,12 +65,17 @@ define linkonce_odr void @f6() unnamed_addr {
 }
 @g6 = global void()* @f6
 
+define i32* @f7() {
+  ret i32* @g7
+}
 
 ; API: f1 PREVAILING_DEF_IRONLY
 ; API: f2 PREVAILING_DEF_IRONLY
 ; API: f3 PREVAILING_DEF_IRONLY_EXP
 ; API: f4 PREVAILING_DEF_IRONLY_EXP
 ; API: f5 PREVAILING_DEF_IRONLY_EXP
 ; API: f6 PREVAILING_DEF_IRONLY_EXP
+; API: f7 PREVAILING_DEF_IRONLY_EXP
+; API: g7 UNDEF
 ; API: g5 PREVAILING_DEF_IRONLY_EXP
 ; API: g6 PREVAILING_DEF_IRONLY_EXP

llvm/tools/gold/gold-plugin.cpp

@@ -633,8 +633,10 @@ getModuleForFile(LLVMContext &Context, claimed_file &F, raw_fd_ostream *ApiFile,
       break;
 
     case LDPR_UNDEF:
-      assert(GV->hasComdat());
-      Drop.insert(GV);
+      if (!GV->hasExternalWeakLinkage()) {
+        assert(GV->hasComdat());
+        Drop.insert(GV);
+      }
       break;
 
     case LDPR_PREVAILING_DEF_IRONLY: {