[HLSL] Add -HV option translation to clang-dxc.exe (#83938)

Previously, clang-dxc.exe would not recognize -HV as a valid argument to
DXC, and would be unable to translate the argument to a legal clang
argument. This PR implements a translation of the HV option and its
value to the appropriate clang flag and the appropriate value. It adds a
test by using the -### option to spit out the translated options, and
checks to see that the correct option was generated.
Fixes #83479

---------

Co-authored-by: Chris B <cbieneman@microsoft.com>

clang/include/clang/Basic/LangStandard.h

@@ -139,6 +139,7 @@ struct LangStandard {
   bool isOpenCL() const { return Flags & OpenCL; }
 
   static Kind getLangKind(StringRef Name);
+  static Kind getHLSLLangKind(StringRef Name);
   static const LangStandard &getLangStandardForKind(Kind K);
   static const LangStandard *getLangStandardForName(StringRef Name);
 };

clang/include/clang/Driver/Options.td

@@ -8578,6 +8578,11 @@ def dxc_entrypoint : Option<["--", "/", "-"], "E", KIND_JOINED_OR_SEPARATE>,
                      Group<dxc_Group>,
                      Visibility<[DXCOption]>,
                      HelpText<"Entry point name">;
+def dxc_hlsl_version : Option<["/", "-"], "HV", KIND_JOINED_OR_SEPARATE>,
+                     Group<dxc_Group>,
+                     Visibility<[DXCOption]>,
+                     HelpText<"HLSL Version">,
+                     Values<"2016, 2017, 2018, 2021, 202x">;
 def dxc_validator_path_EQ : Joined<["--"], "dxv-path=">, Group<dxc_Group>,
   HelpText<"DXIL validator installation path">;
 def dxc_disable_validation : DXCFlag<"Vd">,

clang/lib/Basic/LangStandards.cpp

@@ -69,6 +69,16 @@ LangStandard::Kind LangStandard::getLangKind(StringRef Name) {
       .Default(lang_unspecified);
 }
 
+LangStandard::Kind LangStandard::getHLSLLangKind(StringRef Name) {
+  return llvm::StringSwitch<LangStandard::Kind>(Name)
+      .Case("2016", LangStandard::lang_hlsl2016)
+      .Case("2017", LangStandard::lang_hlsl2017)
+      .Case("2018", LangStandard::lang_hlsl2018)
+      .Case("2021", LangStandard::lang_hlsl2021)
+      .Case("202x", LangStandard::lang_hlsl202x)
+      .Default(LangStandard::lang_unspecified);
+}
+
 const LangStandard *LangStandard::getLangStandardForName(StringRef Name) {
   Kind K = getLangKind(Name);
   if (K == lang_unspecified)

clang/lib/Driver/ToolChains/HLSL.cpp

@@ -226,6 +226,21 @@ HLSLToolChain::TranslateArgs(const DerivedArgList &Args, StringRef BoundArch,
       A->claim();
       continue;
     }
+    if (A->getOption().getID() == options::OPT_dxc_hlsl_version) {
+      // Translate -HV into -std for llvm
+      // depending on the value given
+      LangStandard::Kind LangStd = LangStandard::getHLSLLangKind(A->getValue());
+      if (LangStd != LangStandard::lang_unspecified) {
+        LangStandard l = LangStandard::getLangStandardForKind(LangStd);
+        DAL->AddSeparateArg(nullptr, Opts.getOption(options::OPT_std_EQ),
+                            l.getName());
+      } else {
+        getDriver().Diag(diag::err_drv_invalid_value) << "HV" << A->getValue();
+      }
+
+      A->claim();
+      continue;
+    }
     DAL->append(A);
   }
 

clang/test/Options/HV.hlsl

@@ -0,0 +1,20 @@
+// RUN: %clang_dxc -T lib_6_4 -HV 2016 %s 2>&1 -###   | FileCheck -check-prefix=2016 %s
+// RUN: %clang_dxc -T lib_6_4 -HV 2017 %s 2>&1 -###   | FileCheck -check-prefix=2017 %s
+// RUN: %clang_dxc -T lib_6_4 /HV 2018 %s 2>&1 -###   | FileCheck -check-prefix=2018 %s
+// RUN: %clang_dxc -T lib_6_4 /HV 2021 %s 2>&1 -###   | FileCheck -check-prefix=2021 %s
+// RUN: %clang_dxc -T lib_6_4 /HV 202x %s 2>&1 -###   | FileCheck -check-prefix=202x %s
+// RUN: %clang_dxc -T lib_6_4 %s 2>&1 -###   | FileCheck -check-prefix=NO_HV %s
+// RUN: not %clang_dxc -T lib_6_4 /HV gibberish -### %s 2>&1 | FileCheck -check-prefix=CHECK-ERR %s
+
+// 2016: "-std=hlsl2016"
+// 2017: "-std=hlsl2017"
+// 2018: "-std=hlsl2018"
+// 2021: "-std=hlsl2021"
+// 202x: "-std=hlsl202x"
+// NO_HV-NOT: "-std="
+// CHECK-ERR: error: invalid value 'gibberish' in 'HV'
+float4 main(float4 a : A) : SV_TARGET
+{
+  return -a.yxxx;
+}
+