[Clang] - Add '-gsplit-dwarf[=split,=single]' version for '-gsplit-dwarf' option.

The DWARF5 specification says(Appendix F.1):

"The sections that do not require relocation, however, can be
written to the relocatable object (.o) file but ignored by the
linker or they can be written to a separate DWARF object (.dwo)
file that need not be accessed by the linker."

The first part describes a single file split DWARF feature and there
is no way to trigger this behavior atm. 
Fortunately, no many changes are required to keep *.dwo sections
in a .o, the patch does that.

Differential revision: https://reviews.llvm.org/D52296

llvm-svn: 346837

1 files changed, 6 insertions, 1 deletions

diff --git a/clang/lib/Driver/ToolChains/CommonArgs.cpp b/clang/lib/Driver/ToolChains/CommonArgs.cpp
index 3803dde8daf..e802ce7a8c0 100644
--- a/clang/lib/Driver/ToolChains/CommonArgs.cpp
+++ b/clang/lib/Driver/ToolChains/CommonArgs.cpp
@@ -808,7 +808,12 @@ bool tools::areOptimizationsEnabled(const ArgList &Args) {
   return false;
 }
 
-const char *tools::SplitDebugName(const ArgList &Args, const InputInfo &Input) {
+const char *tools::SplitDebugName(const ArgList &Args, const InputInfo &Input,
+                                  const InputInfo &Output) {
+  if (Arg *A = Args.getLastArg(options::OPT_gsplit_dwarf_EQ))
+    if (StringRef(A->getValue()) == "single")
+      return Args.MakeArgString(Output.getFilename());
+
   Arg *FinalOutput = Args.getLastArg(options::OPT_o);
   if (FinalOutput && Args.hasArg(options::OPT_c)) {
     SmallString<128> T(FinalOutput->getValue());