[AMDGPU] Set default dwarf version to 2

Differential Revision: http://reviews.llvm.org/D20640

llvm-svn: 271347

clang/lib/Driver/ToolChains.h

@@ -943,6 +943,7 @@ protected:
 public:
   AMDGPUToolChain(const Driver &D, const llvm::Triple &Triple,
             const llvm::opt::ArgList &Args);
+  unsigned GetDefaultDwarfVersion() const override { return 2; }
   bool IsIntegratedAssemblerDefault() const override { return true; }
 };
 

clang/test/Driver/amdgpu-toolchain.c

@@ -1,3 +1,6 @@
 // RUN: %clang -### -target amdgcn--amdhsa -x assembler -mcpu=kaveri %s 2>&1 | FileCheck -check-prefix=AS_LINK %s
 // AS_LINK: clang{{.*}} "-cc1as"
 // AS_LINK: ld.lld{{.*}} "-shared"
+
+// RUN: %clang -### -g -target amdgcn--amdhsa -mcpu=kaveri %s 2>&1 | FileCheck -check-prefix=DWARF_VER %s
+// DWARF_VER: "-dwarf-version=2"