First part of support for generating dwarf for assembly source files with the

-g flag.  In this part we generate the .file for the source being assembled and
the .loc's for the assembled instructions.

The next part will be to generate the dwarf Compile Unit DIE and a dwarf
subprogram DIE for each non-temporary label.

Once the next part is done test cases will be added.  rdar://9275556


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@143509 91177308-0d34-0410-b5e6-96231b3b80d8

tools/llvm-mc/llvm-mc.cpp

@@ -152,6 +152,10 @@ NoInitialTextSection("n", cl::desc("Don't assume assembly file starts "
 static cl::opt<bool>
 SaveTempLabels("L", cl::desc("Don't discard temporary labels"));
 
+static cl::opt<bool>
+GenDwarfForAssembly("g", cl::desc("Generate dwarf debugging info for assembly "
+                                  "source files"));
+
 enum ActionType {
   AC_AsLex,
   AC_Assemble,
@@ -377,6 +381,8 @@ static int AssembleInput(const char *ProgName) {
   if (SaveTempLabels)
     Ctx.setAllowTemporaryLabels(false);
 
+  Ctx.setGenDwarfForAssembly(GenDwarfForAssembly);
+
   // Package up features to be passed to target/subtarget
   std::string FeaturesStr;
   if (MAttrs.size()) {