Make the default dwarf version 3 for darwin when we can't find one

in the module. Add a FIXME with a comment about darwin's ld.

llvm-svn: 189902

1 files changed, 5 insertions, 1 deletions

diff --git a/llvm/lib/CodeGen/AsmPrinter/DwarfDebug.cpp b/llvm/lib/CodeGen/AsmPrinter/DwarfDebug.cpp
index b1a75fba6ca..ce684ffe80a 100644
--- a/llvm/lib/CodeGen/AsmPrinter/DwarfDebug.cpp
+++ b/llvm/lib/CodeGen/AsmPrinter/DwarfDebug.cpp
@@ -174,8 +174,12 @@ DIType DbgVariable::getType() const {
 /// Return Dwarf Version by checking module flags.
 static unsigned getDwarfVersionFromModule(const Module *M) {
   Value *Val = M->getModuleFlag("Dwarf Version");
+  // If we don't have a value in the module go ahead and use the default in
+  // dwarf::DWARF_VERSION.
+  // FIXME: Apple ld has a problem parsing compilation units that specify a
+  // dwarf version of greater than 3.
   if (!Val)
-    return dwarf::DWARF_VERSION;
+    return Triple(M->getTargetTriple()).isOSDarwin() ? 3 : dwarf::DWARF_VERSION;
   return cast<ConstantInt>(Val)->getZExtValue();
 }