[HLSL] emit-obj when set output.

When not set output, set default output to stdout.
When set output with -Fo and no -fcgl, set -emit-obj to generate dx container.

Reviewed By: beanz

Differential Revision: https://reviews.llvm.org/D130858

Author: python3kgae

clang/lib/Driver/Driver.cpp

@@ -5664,6 +5664,9 @@ const char *Driver::GetNamedOutputPath(Compilation &C, const JobAction &JA,
     return "-";
   }
 
+  if (IsDXCMode() && !C.getArgs().hasArg(options::OPT_o))
+    return "-";
+
   // Is this the assembly listing for /FA?
   if (JA.getType() == types::TY_PP_Asm &&
       (C.getArgs().hasArg(options::OPT__SLASH_FA) ||

clang/lib/Driver/ToolChains/Clang.cpp

@@ -3513,6 +3513,7 @@ static void RenderHLSLOptions(const ArgList &Args, ArgStringList &CmdArgs,
                                          options::OPT_I,
                                          options::OPT_S,
                                          options::OPT_emit_llvm,
+                                         options::OPT_emit_obj,
                                          options::OPT_disable_llvm_passes,
                                          options::OPT_fnative_half_type,
                                          options::OPT_hlsl_entrypoint};

clang/lib/Driver/ToolChains/HLSL.cpp

@@ -175,6 +175,15 @@ HLSLToolChain::TranslateArgs(const DerivedArgList &Args, StringRef BoundArch,
     }
     DAL->append(A);
   }
+
+  if (DAL->hasArg(options::OPT_o)) {
+    // When run the whole pipeline.
+    if (!DAL->hasArg(options::OPT_emit_llvm))
+      // Emit obj if write to file.
+      DAL->AddFlagArg(nullptr, Opts.getOption(options::OPT_emit_obj));
+  } else
+    DAL->AddSeparateArg(nullptr, Opts.getOption(options::OPT_o), "-");
+
   // Add default validator version if not set.
   // TODO: remove this once read validator version from validator.
   if (!DAL->hasArg(options::OPT_dxil_validator_version)) {

clang/test/Driver/dxc_Fo.hlsl

@@ -0,0 +1,15 @@
+// RUN: %clang_dxc -T lib_6_7 foo.hlsl -### %s 2>&1 | FileCheck %s --check-prefix=DEFAULT
+// RUN: %clang_dxc -fcgl -T lib_6_7 foo.hlsl -### %s 2>&1 | FileCheck %s --check-prefix=FCGL
+// RUN: %clang_dxc  -T lib_6_7 foo.hlsl -Fo foo.dxc -### %s 2>&1 | FileCheck %s --check-prefix=EMITOBJ
+
+
+// Make sure default use "-" as output and not emit obj.
+// DEFAULT-NOT:"-emit-obj"
+// DEFAULT:"-o" "-"
+
+// Make sure -fcgl without -Fo use "-" as output.
+// FCGL:"-o" "-"
+
+
+// Make sure emit-obj when set -Fo.
+// EMITOBJ:"-emit-obj"