[clang] [llvm] [DirectX] Validate registers are bound to root signature (PR #146785)

[via llvm-commits]

================
@@ -84,8 +128,150 @@ static void reportOverlappingBinding(Module &M, DXILResourceMap &DRM) {
   }
 }
 
+static void reportRegNotBound(Module &M,
+                              llvm::hlsl::rootsig::RangeInfo Unbound) {
+  SmallString<128> Message;
+  raw_svector_ostream OS(Message);
+  OS << "register " << ResourceClassToString(Unbound.Class)
+     << " (space=" << Unbound.Space << ", register=" << Unbound.LowerBound
+     << ")"
+     << " does not have a binding in the Root Signature";
+  M.getContext().diagnose(DiagnosticInfoGeneric(Message));
+}
+
+static dxbc::ShaderVisibility
+tripleToVisibility(llvm::Triple::EnvironmentType ET) {
+  assert((ET == Triple::Pixel || ET == Triple::Vertex ||
+          ET == Triple::Geometry || ET == Triple::Hull ||
+          ET == Triple::Domain || ET == Triple::Mesh ||
+          ET == Triple::Compute) &&
+         "Invalid Triple to shader stage conversion");
+
+  switch (ET) {
+  case Triple::Pixel:
+    return dxbc::ShaderVisibility::Pixel;
+  case Triple::Vertex:
+    return dxbc::ShaderVisibility::Vertex;
+  case Triple::Geometry:
+    return dxbc::ShaderVisibility::Geometry;
+  case Triple::Hull:
+    return dxbc::ShaderVisibility::Hull;
+  case Triple::Domain:
+    return dxbc::ShaderVisibility::Domain;
+  case Triple::Mesh:
+    return dxbc::ShaderVisibility::Mesh;
+  case Triple::Compute:
+    return dxbc::ShaderVisibility::All;
+  default:
+    llvm_unreachable("Invalid triple to shader stage conversion");
+  }
+}
+
+static hlsl::rootsig::RootSignatureBindingValidation
+initRSBindingValidation(const mcdxbc::RootSignatureDesc &RSD,
+                        dxbc::ShaderVisibility Visibility) {
+
+  hlsl::rootsig::RootSignatureBindingValidation Validation;
+
+  for (size_t I = 0; I < RSD.ParametersContainer.size(); I++) {
+    const auto &[Type, Loc] =
+        RSD.ParametersContainer.getTypeAndLocForParameter(I);
+
+    const auto &Header = RSD.ParametersContainer.getHeader(I);
+    if (Header.ShaderVisibility !=
+            llvm::to_underlying(dxbc::ShaderVisibility::All) &&
+        Header.ShaderVisibility != llvm::to_underlying(Visibility))
+      continue;
+
+    switch (Type) {
+    case llvm::to_underlying(dxbc::RootParameterType::Constants32Bit): {
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joaosaffran wrote:

This was originally a design decision. The decision was made to avoid converting uint_32t to enum in obj2yaml/yaml2obj and when reading and writing root signature to/from the binary format. This simplified the code at the time. 

https://github.com/llvm/llvm-project/pull/146785