diff --git a/llvm/lib/Linker/LinkModules.cpp b/llvm/lib/Linker/LinkModules.cpp --- a/llvm/lib/Linker/LinkModules.cpp +++ b/llvm/lib/Linker/LinkModules.cpp @@ -179,9 +179,25 @@ // Go with Dst. From = LinkFrom::Dst; break; - case Comdat::SelectionKind::NoDeduplicate: - return emitError("Linking COMDATs named '" + ComdatName + - "': nodeduplicate has been violated!"); + case Comdat::SelectionKind::NoDeduplicate: { + const GlobalVariable *DstGV; + const GlobalVariable *SrcGV; + if (getComdatLeader(DstM, ComdatName, DstGV) || + getComdatLeader(*SrcM, ComdatName, SrcGV)) + return true; + + if (SrcGV->isWeakForLinker()) { + // Go with Dst. + From = LinkFrom::Dst; + } else if (DstGV->isWeakForLinker()) { + // Go with Src. + From = LinkFrom::Src; + } else { + return emitError("Linking COMDATs named '" + ComdatName + + "': nodeduplicate has been violated!"); + } + break; + } case Comdat::SelectionKind::ExactMatch: case Comdat::SelectionKind::Largest: case Comdat::SelectionKind::SameSize: { diff --git a/llvm/test/Linker/comdat-nodeduplicate.ll b/llvm/test/Linker/comdat-nodeduplicate.ll --- a/llvm/test/Linker/comdat-nodeduplicate.ll +++ b/llvm/test/Linker/comdat-nodeduplicate.ll @@ -3,14 +3,16 @@ ; CHECK: error: Linking COMDATs named 'foo': nodeduplicate has been violated! -; RUN: not llvm-link -S %t/2.ll %t/2-aux.ll 2>&1 | FileCheck %s --check-prefix=CHECK2 -; RUN: not llvm-link -S %t/2-aux.ll %t/2.ll 2>&1 | FileCheck %s --check-prefix=CHECK2 +; RUN: llvm-link -S %t/2.ll %t/2-aux.ll | FileCheck %s --check-prefix=CHECK2 +; RUN: llvm-link -S %t/2-aux.ll %t/2.ll | FileCheck %s --check-prefix=CHECK2 -; CHECK2: error: Linking COMDATs named 'foo' +; CHECK2-DAG: @foo = global i64 2, section "data", comdat, align 8 +; CHECK2-DAG: @bar = weak global i64 0, section "cnts", comdat($foo) +; CHECK2-DAG: @qux = weak_odr global i64 4, comdat($foo) ; RUN: not llvm-link -S %t/non-var.ll %t/non-var.ll 2>&1 | FileCheck %s --check-prefix=NONVAR -; NONVAR: error: Linking COMDATs named 'foo': nodeduplicate has been violated! +; NONVAR: error: Linking COMDATs named 'foo': GlobalVariable required for data dependent selection! ;--- 1.ll $foo = comdat nodeduplicate