Add -validator-version override

- remove auto-Vd on lib < 6.3, since this is already required to be
  explicit by option parsing.

include/dxc/Support/HLSLOptions.h

@@ -164,6 +164,7 @@ public:
   unsigned long AutoBindingSpace = UINT_MAX; // OPT_auto_binding_space
   bool ExportShadersOnly = false; // OPT_export_shaders_only
   bool ResMayAlias = false; // OPT_res_may_alias
+  unsigned long ValVerMajor = 0, ValVerMinor = 0; // OPT_validator_version
 
   bool IsRootSignatureProfile();
   bool IsLibraryProfile();

include/dxc/Support/HLSLOptions.td

@@ -242,6 +242,8 @@ def export_shaders_only : Flag<["-", "/"], "export-shaders-only">, Group<hlslcom
   HelpText<"Only export shaders when compiling a library">;
 def default_linkage : Separate<["-", "/"], "default-linkage">, Group<hlslcomp_Group>, Flags<[CoreOption]>,
   HelpText<"Set default linkage for non-shader functions when compiling or linking to a library target (internal, external)">;
+def validator_version : Separate<["-", "/"], "validator-version">, Group<hlslcomp_Group>, Flags<[CoreOption]>,
+  HelpText<"Override validator version for module.  Format: <major>,<minor>.  Default: DXIL.dll version or current internal version.">;
 
 // SPIRV Change Starts
 def spirv : Flag<["-"], "spirv">, Group<spirv_Group>, Flags<[CoreOption, DriverOption]>,

lib/DxcSupport/HLSLOptions.cpp

@@ -13,6 +13,7 @@
 #include "llvm/Option/Option.h"
 #include "llvm/Support/raw_ostream.h"
 #include "llvm/Support/Path.h"
+#include "llvm/ADT/APInt.h"
 #include "dxc/Support/Global.h"
 #include "dxc/Support/WinIncludes.h"
 #include "dxc/Support/HLSLOptions.h"
@@ -642,11 +643,45 @@ int ReadDxcOpts(const OptTable *optionTable, unsigned flagsToInclude,
     return 1;
   }
 
+  llvm::StringRef valVersionStr = Args.getLastArgValue(OPT_validator_version);
+  if (!valVersionStr.empty()) {
+    // Parse "major,minor" version string
+    auto verPair = valVersionStr.split(",");
+    llvm::APInt major, minor;
+    if (verPair.first.getAsInteger(0, major) || verPair.second.getAsInteger(0, minor)) {
+      errors << "Format of validator version is \"<major>,<minor>\" (ex: \"1,4\").";
+      return 1;
+    }
+    uint16_t major64 = major.getLimitedValue();
+    uint16_t minor64 = minor.getLimitedValue();
+    if (major64 > DXIL::kDxilMajor ||
+        (major64 == DXIL::kDxilMajor && minor64 > DXIL::kDxilMinor)) {
+      errors << "Validator version must be less than or equal to current internal version.";
+      return 1;
+    }
+    if (major64 == 0 && minor64 != 0) {
+      errors << "If validator major version is 0, minor version must also be 0.";
+      return 1;
+    }
+    opts.ValVerMajor = (unsigned long)major64;
+    opts.ValVerMinor = (unsigned long)minor64;
+  }
+
   if (opts.IsLibraryProfile() && Minor == 0xF) {
+    if (opts.ValVerMajor != 0) {
+      errors << "Offline library profile cannot be used with non-zero -validator-version.";
+      return 1;
+    }
     // Disable validation for offline link only target
     opts.DisableValidation = true;
+
+    // ValVerMajor == 0 means that the module is not meant to ever be validated.
+    opts.ValVerMajor = 0;
+    opts.ValVerMinor = 0;
   }
 
+  // These targets are only useful as an intermediate step towards linking to matching
+  // shader targets without going through target downgrading at link time.
   // Disable lib_6_1 and lib_6_2 if /Vd is not present
   if (opts.IsLibraryProfile() && (Major < 6 || (Major == 6 && Minor < 3))) {
     if (!opts.DisableValidation) {
@@ -654,6 +689,14 @@ int ReadDxcOpts(const OptTable *optionTable, unsigned flagsToInclude,
                 "targets.";
       return 1;
     }
+    if (opts.ValVerMajor != 0) {
+      errors << "non-zero -validator-version cannot be used with library profiles lib_6_1 or lib_6_2.";
+      return 1;
+    }
+
+    // ValVerMajor == 0 means that the module is not meant to ever be validated.
+    opts.ValVerMajor = 0;
+    opts.ValVerMinor = 0;
   }
 
     // SPIRV Change Starts

tools/clang/tools/dxcompiler/dxcompilerobj.cpp

@@ -616,19 +616,16 @@ public:
       // NOTE: this calls the validation component from dxil.dll; the built-in
       // validator can be used as a fallback.
       bool produceFullContainer = !opts.CodeGenHighLevel && !opts.AstDump && !opts.OptDump && rootSigMajor == 0;
-
       bool needsValidation = produceFullContainer && !opts.DisableValidation;
-      // Disable validation for lib_6_1 and lib_6_2.
-      if (compiler.getCodeGenOpts().HLSLProfile == "lib_6_1" ||
-          compiler.getCodeGenOpts().HLSLProfile == "lib_6_2") {
-        needsValidation = false;
-      }
 
-      if (needsValidation || (opts.CodeGenHighLevel && !opts.DisableValidation)) {
-        UINT32 majorVer, minorVer;
-        dxcutil::GetValidatorVersion(&majorVer, &minorVer);
-        compiler.getCodeGenOpts().HLSLValidatorMajorVer = majorVer;
-        compiler.getCodeGenOpts().HLSLValidatorMinorVer = minorVer;
+      if (opts.ValVerMajor > 0) {
+        // user-specified validator version override
+        compiler.getCodeGenOpts().HLSLValidatorMajorVer = opts.ValVerMajor;
+        compiler.getCodeGenOpts().HLSLValidatorMinorVer = opts.ValVerMinor;
+      } else {
+        // Version from dxil.dll, or internal validator if unavailable
+        dxcutil::GetValidatorVersion(&compiler.getCodeGenOpts().HLSLValidatorMajorVer,
+                                     &compiler.getCodeGenOpts().HLSLValidatorMinorVer);
       }
 
       if (opts.AstDump) {