[CUDA] pass debug options to ptxas.

ptxas optimizations are disabled if we need to generate debug info
as ptxas does not accept '-g' otherwise.

Differential Revision: http://reviews.llvm.org/D17111

llvm-svn: 261018

1 files changed, 11 insertions, 9 deletions

diff --git a/clang/lib/Driver/Tools.cpp b/clang/lib/Driver/Tools.cpp
index 44d6b84..1599367 100644
--- a/clang/lib/Driver/Tools.cpp
+++ b/clang/lib/Driver/Tools.cpp
@@ -10691,15 +10691,20 @@ void NVPTX::Assembler::ConstructJob(Compilation &C, const JobAction &JA,
   assert(gpu_archs.size() == 1 && "Exactly one GPU Arch required for ptxas.");
   const std::string& gpu_arch = gpu_archs[0];
 
-
   ArgStringList CmdArgs;
   CmdArgs.push_back(TC.getTriple().isArch64Bit() ? "-m64" : "-m32");
+  if (Args.getLastArg(options::OPT_cuda_noopt_device_debug)) {
+    // ptxas does not accept -g option if optimization is enabled, so
+    // we ignore the compiler's -O* options if we want debug info.
+    CmdArgs.push_back("-g");
+    CmdArgs.push_back("--dont-merge-basicblocks");
+    CmdArgs.push_back("--return-at-end");
+  } else if (Arg *A = Args.getLastArg(options::OPT_O_Group)) {
+    // Map the -O we received to -O{0,1,2,3}.
+    //
+    // TODO: Perhaps we should map host -O2 to ptxas -O3. -O3 is ptxas's
+    // default, so it may correspond more closely to the spirit of clang -O2.
 
-  // Map the -O we received to -O{0,1,2,3}.
-  //
-  // TODO: Perhaps we should map host -O2 to ptxas -O3. -O3 is ptxas's default,
-  // so it may correspond more closely to the spirit of clang -O2.
-  if (Arg *A = Args.getLastArg(options::OPT_O_Group)) {
     // -O3 seems like the least-bad option when -Osomething is specified to
     // clang but it isn't handled below.
     StringRef OOpt = "3";
@@ -10725,9 +10730,6 @@ void NVPTX::Assembler::ConstructJob(Compilation &C, const JobAction &JA,
     CmdArgs.push_back("-O0");
   }
 
-  // Don't bother passing -g to ptxas: It's enabled by default at -O0, and
-  // not supported at other optimization levels.
-
   CmdArgs.push_back("--gpu-name");
   CmdArgs.push_back(Args.MakeArgString(gpu_arch));
   CmdArgs.push_back("--output-file");