Fix dangling reference in DwarfLinker.cpp. The original code

  Seq.emplace_back(Seq.back());

does not work as planned, since Seq.back() may become a dangling reference
when emplace_back is called and possibly reallocates vector. To avoid this,
the vector allocation should be reserved first and only then used.

This broke test/tools/dsymutil/X86/custom-line-table.test with Visual C++ 2013.

llvm-svn: 244405

1 files changed, 1 insertions, 0 deletions

diff --git a/llvm/tools/dsymutil/DwarfLinker.cpp b/llvm/tools/dsymutil/DwarfLinker.cpp
index 47d08504786..d839f07657b 100644
--- a/llvm/tools/dsymutil/DwarfLinker.cpp
+++ b/llvm/tools/dsymutil/DwarfLinker.cpp
@@ -2884,6 +2884,7 @@ void DwarfLinker::patchLineTableForUnit(CompileUnit &Unit,
       if (StopAddress != -1ULL && !Seq.empty()) {
         // Insert end sequence row with the computed end address, but
         // the same line as the previous one.
+        Seq.reserve(Seq.size() + 1);
         Seq.emplace_back(Seq.back());
         Seq.back().Address = StopAddress;
         Seq.back().EndSequence = 1;