[DirectX] Fix Flags validation to prevent casting into enum

clang/lib/Sema/SemaHLSL.cpp

@@ -1322,8 +1322,8 @@ bool SemaHLSL::handleRootSignatureElements(
         ReportError(Loc, 1, 0xfffffffe);
       }
 
-      if (!llvm::hlsl::rootsig::verifyDescriptorRangeFlag(Version, Clause->Type,
-                                                          Clause->Flags))
+      if (!llvm::hlsl::rootsig::verifyDescriptorRangeFlag(
+              Version, Clause->Type, llvm::to_underlying(Clause->Flags)))
         ReportFlagError(Loc);
     }
   }

llvm/include/llvm/Frontend/HLSL/RootSignatureValidations.h

@@ -32,7 +32,7 @@ LLVM_ABI bool verifyRootDescriptorFlag(uint32_t Version, uint32_t FlagsVal);
 LLVM_ABI bool verifyRangeType(uint32_t Type);
 LLVM_ABI bool verifyDescriptorRangeFlag(uint32_t Version,
                                         dxil::ResourceClass Type,
-                                        dxbc::DescriptorRangeFlags FlagsVal);
+                                        uint32_t FlagsVal);
 LLVM_ABI bool verifyStaticSamplerFlags(uint32_t Version, uint32_t FlagsNumber);
 LLVM_ABI bool verifyNumDescriptors(uint32_t NumDescriptors);
 LLVM_ABI bool verifyMipLODBias(float MipLODBias);

llvm/lib/Frontend/HLSL/RootSignatureMetadata.cpp

@@ -665,8 +665,7 @@ Error MetadataParser::validateRootSignature(
                              "NumDescriptors", Range.NumDescriptors));
 
         if (!hlsl::rootsig::verifyDescriptorRangeFlag(
-                RSD.Version, Range.RangeType,
-                dxbc::DescriptorRangeFlags(Range.Flags)))
+                RSD.Version, Range.RangeType, Range.Flags))
           DeferredErrs =
               joinErrors(std::move(DeferredErrs),
                          make_error<RootSignatureValidationError<uint32_t>>(

llvm/lib/Frontend/HLSL/RootSignatureValidations.cpp

@@ -36,6 +36,11 @@ bool verifyRegisterSpace(uint32_t RegisterSpace) {
 
 bool verifyRootDescriptorFlag(uint32_t Version, uint32_t FlagsVal) {
   using FlagT = dxbc::RootDescriptorFlags;
+  uint32_t LargestValue =
+      llvm::to_underlying(FlagT::LLVM_BITMASK_LARGEST_ENUMERATOR);
+  if (FlagsVal >= NextPowerOf2(LargestValue))
+    return false;
+
   FlagT Flags = FlagT(FlagsVal);
   if (Version == 1)
     return Flags == FlagT::DataVolatile;
@@ -54,9 +59,14 @@ bool verifyRootDescriptorFlag(uint32_t Version, uint32_t FlagsVal) {
 }
 
 bool verifyDescriptorRangeFlag(uint32_t Version, dxil::ResourceClass Type,
-                               dxbc::DescriptorRangeFlags Flags) {
+                               uint32_t FlagsVal) {
   using FlagT = dxbc::DescriptorRangeFlags;
+  uint32_t LargestValue =
+      llvm::to_underlying(FlagT::LLVM_BITMASK_LARGEST_ENUMERATOR);
+  if (FlagsVal >= NextPowerOf2(LargestValue))
+    return false;
 
+  FlagT Flags = FlagT(FlagsVal);
   const bool IsSampler = (Type == dxil::ResourceClass::Sampler);
 
   if (Version == 1) {

llvm/test/CodeGen/DirectX/ContainerData/RootSignature-DescriptorTable-Invalid-Flag-LargeNumber.ll

@@ -0,0 +1,20 @@
+; RUN: not opt -passes='print<dxil-root-signature>' %s -S -o - 2>&1 | FileCheck %s
+
+target triple = "dxil-unknown-shadermodel6.0-compute"
+
+; CHECK: error: Invalid value for DescriptorFlag: 66666
+; CHECK-NOT: Root Signature Definitions
+
+define void @main() #0 {
+entry:
+  ret void
+}
+attributes #0 = { "hlsl.numthreads"="1,1,1" "hlsl.shader"="compute" }
+
+
+!dx.rootsignatures = !{!2} ; list of function/root signature pairs
+!2 = !{ ptr @main, !3, i32 2 } ; function, root signature
+!3 = !{ !5 } ; list of root signature elements
+!5 = !{ !"DescriptorTable", i32 0, !6, !7 }
+!6 = !{ !"SRV", i32 1, i32 1, i32 0, i32 -1, i32 66666 }
+!7 = !{ !"UAV", i32 5, i32 1, i32 10, i32 5, i32 2 }

llvm/test/CodeGen/DirectX/ContainerData/RootSignature-RootDescriptor-Invalid-Flags-LargeNumber.ll

@@ -0,0 +1,18 @@
+; RUN: not opt -passes='print<dxil-root-signature>' %s -S -o - 2>&1 | FileCheck %s
+
+target triple = "dxil-unknown-shadermodel6.0-compute"
+
+
+; CHECK: error: Invalid value for RootDescriptorFlag: 666
+; CHECK-NOT: Root Signature Definitions
+define void @main() #0 {
+entry:
+  ret void
+}
+attributes #0 = { "hlsl.numthreads"="1,1,1" "hlsl.shader"="compute" }
+
+
+!dx.rootsignatures = !{!2} ; list of function/root signature pairs
+!2 = !{ ptr @main, !3, i32 2 } ; function, root signature
+!3 = !{ !5 } ; list of root signature elements
+!5 = !{ !"RootCBV", i32 0, i32 1, i32 2, i32 666  }