[llvm] r244405 - Fix dangling reference in DwarfLinker.cpp. The original code

[Yaron Keren via llvm-commits]

Author: yrnkrn
Date: Sat Aug  8 16:03:19 2015
New Revision: 244405

URL: http://llvm.org/viewvc/llvm-project?rev=244405&view=rev
Log:
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.


Modified:
    llvm/trunk/tools/dsymutil/DwarfLinker.cpp

Modified: llvm/trunk/tools/dsymutil/DwarfLinker.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/tools/dsymutil/DwarfLinker.cpp?rev=244405&r1=244404&r2=244405&view=diff
==============================================================================
--- llvm/trunk/tools/dsymutil/DwarfLinker.cpp (original)
+++ llvm/trunk/tools/dsymutil/DwarfLinker.cpp Sat Aug  8 16:03:19 2015
@@ -2884,6 +2884,7 @@ void DwarfLinker::patchLineTableForUnit(
       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;