[llvm] r215364 - Fix use of uninitialized variable.

[Rafael Espindola]

Author: rafael
Date: Mon Aug 11 12:07:34 2014
New Revision: 215364

URL: http://llvm.org/viewvc/llvm-project?rev=215364&view=rev
Log:
Fix use of uninitialized variable.

Fixes linking bitcode files that use the new style comdats for constructors
with ones that don't.

Added:
    llvm/trunk/test/Linker/Inputs/constructor-comdat.ll
    llvm/trunk/test/Linker/constructor-comdat.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=215364&r1=215363&r2=215364&view=diff
==============================================================================
--- llvm/trunk/lib/Linker/LinkModules.cpp (original)
+++ llvm/trunk/lib/Linker/LinkModules.cpp Mon Aug 11 12:07:34 2014
@@ -644,15 +644,19 @@ bool ModuleLinker::computeResultingSelec
 bool ModuleLinker::getComdatResult(const Comdat *SrcC,
                                    Comdat::SelectionKind &Result,
                                    bool &LinkFromSrc) {
+  Comdat::SelectionKind SSK = SrcC->getSelectionKind();
   StringRef ComdatName = SrcC->getName();
   Module::ComdatSymTabType &ComdatSymTab = DstM->getComdatSymbolTable();
   Module::ComdatSymTabType::iterator DstCI = ComdatSymTab.find(ComdatName);
 
-  if (DstCI == ComdatSymTab.end())
+  if (DstCI == ComdatSymTab.end()) {
+    // Use the comdat if it is only available in one of the modules.
+    LinkFromSrc = true;
+    Result = SSK;
     return false;
+  }
 
   const Comdat *DstC = &DstCI->second;
-  Comdat::SelectionKind SSK = SrcC->getSelectionKind();
   Comdat::SelectionKind DSK = DstC->getSelectionKind();
   return computeResultingSelectionKind(ComdatName, SSK, DSK, Result,
                                        LinkFromSrc);

Added: llvm/trunk/test/Linker/Inputs/constructor-comdat.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Linker/Inputs/constructor-comdat.ll?rev=215364&view=auto
==============================================================================
--- llvm/trunk/test/Linker/Inputs/constructor-comdat.ll (added)
+++ llvm/trunk/test/Linker/Inputs/constructor-comdat.ll Mon Aug 11 12:07:34 2014
@@ -0,0 +1,7 @@
+define weak_odr void @_ZN3fooIiEC2Ev() {
+  ret void
+}
+
+define weak_odr void @_ZN3fooIiEC1Ev() {
+  ret void
+}

Added: llvm/trunk/test/Linker/constructor-comdat.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Linker/constructor-comdat.ll?rev=215364&view=auto
==============================================================================
--- llvm/trunk/test/Linker/constructor-comdat.ll (added)
+++ llvm/trunk/test/Linker/constructor-comdat.ll Mon Aug 11 12:07:34 2014
@@ -0,0 +1,13 @@
+; RUN: llvm-link %s %p/Inputs/constructor-comdat.ll -S -o - 2>&1 | FileCheck %s
+; RUN: llvm-link %p/Inputs/constructor-comdat.ll %s -S -o - 2>&1 | FileCheck %s
+
+$_ZN3fooIiEC5Ev = comdat any
+; CHECK: $_ZN3fooIiEC5Ev = comdat any
+
+ at _ZN3fooIiEC1Ev = weak_odr alias void ()* @_ZN3fooIiEC2Ev
+; CHECK: @_ZN3fooIiEC1Ev = weak_odr alias void ()* @_ZN3fooIiEC2Ev
+
+; CHECK: define weak_odr void @_ZN3fooIiEC2Ev() comdat $_ZN3fooIiEC5Ev {
+define weak_odr void @_ZN3fooIiEC2Ev() comdat $_ZN3fooIiEC5Ev {
+  ret void
+}