[HLSL] Use HLSLToolChain for Vulkan (llvm#110306)

The options are not translated correctly when targeting Vulkan using the
dxc
driver mode. Resuing the translator used for HLSL.

Fixes problem 2 in llvm#108567.

Author: s-perron

clang/lib/Driver/Driver.cpp

@@ -6481,6 +6481,7 @@ const ToolChain &Driver::getToolChain(const ArgList &Args,
     case llvm::Triple::ZOS:
       TC = std::make_unique<toolchains::ZOS>(*this, Target, Args);
       break;
+    case llvm::Triple::Vulkan:
     case llvm::Triple::ShaderModel:
       TC = std::make_unique<toolchains::HLSLToolChain>(*this, Target, Args);
       break;

clang/test/CodeGenHLSL/entry.hlsl

@@ -2,6 +2,10 @@
 // RUN:   dxil-pc-shadermodel6.3-compute %s -hlsl-entry foo \
 // RUN:   -emit-llvm -disable-llvm-passes -o - | FileCheck %s
 
+// RUN: %clang_cc1 -std=hlsl2021 -finclude-default-header -x hlsl -triple \
+// RUN:   spirv-unknown-vulkan-compute %s -hlsl-entry foo \
+// RUN:   -emit-llvm -disable-llvm-passes -o - | FileCheck %s
+
 // Make sure not mangle entry.
 // CHECK:define void @foo()
 // Make sure add function attribute and numthreads attribute.

clang/test/Driver/dxc_E.hlsl

@@ -1,4 +1,5 @@
 // RUN: not %clang_dxc -Efoo -Tlib_6_7 foo.hlsl -### %s 2>&1 | FileCheck %s
+// RUN: not %clang_dxc -Efoo -Tlib_6_7 -spirv foo.hlsl -### %s 2>&1 | FileCheck %s
 
 // Make sure E option flag which translated into "-hlsl-entry".
 // CHECK:"-hlsl-entry" "foo"