[SPIRV][HLSL] Add Sema and CodeGen for implicit typed buffer counters

This commit implements the Sema and CodeGen portions of the typed buffer
counter proposal described in the HLSL WG proposal 0023.

This change introduces the necessary Sema and CodeGen logic to handle
implicit counter variables for typed buffers. This includes:

- Extending `HLSLResourceBindingAttr` to store the implicit counter
  binding order ID.
- Introducing the `__builtin_hlsl_resource_counterhandlefromimplicitbinding`
  builtin.
- Updating `SemaHLSL` to correctly initialize global resource declarations
  and resource arrays with implicit counter buffers.
- Adding CodeGen support for the new builtin, which generates a
  `llvm.spv.resource.counterhandlefromimplicitbinding` intrinsic for the
  SPIR-V target and aliases the main resource handle for the DXIL target.
- Adding and updating tests to verify the new functionality.

Fixes #137032

Author: s-perron

clang/include/clang/AST/HLSLResource.h

@@ -74,6 +74,19 @@ struct ResourceBindingAttrs {
     assert(hasBinding() && !isExplicit() && !hasImplicitOrderID());
     RegBinding->setImplicitBindingOrderID(Value);
   }
+  void setCounterImplicitOrderID(unsigned Value) const {
+    assert(hasBinding() && !hasCounterImplicitOrderID());
+    RegBinding->setImplicitCounterBindingOrderID(Value);
+  }
+
+  bool hasCounterImplicitOrderID() const {
+    return RegBinding && RegBinding->hasImplicitCounterBindingOrderID();
+  }
+
+  unsigned getCounterImplicitOrderID() const {
+    assert(hasCounterImplicitOrderID());
+    return RegBinding->getImplicitCounterBindingOrderID();
+  }
 };
 
 } // namespace hlsl

clang/include/clang/Basic/Attr.td

@@ -4944,6 +4944,7 @@ def HLSLResourceBinding: InheritableAttr {
       std::optional<unsigned> SlotNumber;
       unsigned SpaceNumber;
       std::optional<unsigned> ImplicitBindingOrderID;
+      std::optional<unsigned> ImplicitCounterBindingOrderID;
 
   public:
       void setBinding(RegisterType RT, std::optional<unsigned> SlotNum, unsigned SpaceNum) {
@@ -4976,6 +4977,17 @@ def HLSLResourceBinding: InheritableAttr {
         assert(hasImplicitBindingOrderID() && "attribute does not have implicit binding order id");
         return ImplicitBindingOrderID.value();
       }
+      void setImplicitCounterBindingOrderID(uint32_t Value) {
+        assert(!hasImplicitCounterBindingOrderID() && "attribute already has implicit counter binding order id");
+        ImplicitCounterBindingOrderID = Value;
+      }
+      bool hasImplicitCounterBindingOrderID() const {
+        return ImplicitCounterBindingOrderID.has_value();
+      }
+      uint32_t getImplicitCounterBindingOrderID() const {
+        assert(hasImplicitCounterBindingOrderID() && "attribute does not have implicit counter binding order id");
+        return ImplicitCounterBindingOrderID.value();
+      }
   }];
 }
 

clang/include/clang/Basic/Builtins.td

@@ -4945,6 +4945,12 @@ def HLSLResourceHandleFromImplicitBinding : LangBuiltin<"HLSL_LANG"> {
   let Prototype = "void(...)";
 }
 
+def HLSLResourceCounterHandleFromImplicitBinding : LangBuiltin<"HLSL_LANG"> {
+  let Spellings = ["__builtin_hlsl_resource_counterhandlefromimplicitbinding"];
+  let Attributes = [NoThrow, CustomTypeChecking];
+  let Prototype = "void(...)";
+}
+
 def HLSLResourceNonUniformIndex : LangBuiltin<"HLSL_LANG"> {
   let Spellings = ["__builtin_hlsl_resource_nonuniformindex"];
   let Attributes = [NoThrow];

clang/lib/CodeGen/CGHLSLBuiltins.cpp

@@ -352,6 +352,19 @@ Value *CodeGenFunction::EmitHLSLBuiltinExpr(unsigned BuiltinID,
     SmallVector<Value *> Args{OrderID, SpaceOp, RangeOp, IndexOp, Name};
     return Builder.CreateIntrinsic(HandleTy, IntrinsicID, Args);
   }
+  case Builtin::BI__builtin_hlsl_resource_counterhandlefromimplicitbinding: {
+    llvm::Type *HandleTy = CGM.getTypes().ConvertType(E->getType());
+    Value *MainHandle = EmitScalarExpr(E->getArg(0));
+    if (CGM.getTriple().isSPIRV()) {
+      Value *OrderID = EmitScalarExpr(E->getArg(1));
+      Value *SpaceOp = EmitScalarExpr(E->getArg(2));
+      llvm::Intrinsic::ID IntrinsicID =
+          llvm::Intrinsic::spv_resource_counterhandlefromimplicitbinding;
+      SmallVector<Value *> Args{MainHandle, OrderID, SpaceOp};
+      return Builder.CreateIntrinsic(HandleTy, IntrinsicID, Args);
+    }
+    return MainHandle;
+  }
   case Builtin::BI__builtin_hlsl_resource_nonuniformindex: {
     Value *IndexOp = EmitScalarExpr(E->getArg(0));
     llvm::Type *RetTy = ConvertType(E->getType());

clang/lib/CodeGen/CGHLSLRuntime.cpp

@@ -145,19 +145,34 @@ static CXXMethodDecl *lookupResourceInitMethodAndSetupArgs(
     // explicit binding
     auto *RegSlot = llvm::ConstantInt::get(CGM.IntTy, Binding.getSlot());
     Args.add(RValue::get(RegSlot), AST.UnsignedIntTy);
-    CreateMethod = lookupMethod(ResourceDecl, "__createFromBinding", SC_Static);
+    if (Binding.hasCounterImplicitOrderID())
+      CreateMethod = lookupMethod(
+          ResourceDecl, "__createFromBindingWithImplicitCounter", SC_Static);
+    else
+      CreateMethod =
+          lookupMethod(ResourceDecl, "__createFromBinding", SC_Static);
   } else {
     // implicit binding
     auto *OrderID =
         llvm::ConstantInt::get(CGM.IntTy, Binding.getImplicitOrderID());
     Args.add(RValue::get(OrderID), AST.UnsignedIntTy);
-    CreateMethod =
-        lookupMethod(ResourceDecl, "__createFromImplicitBinding", SC_Static);
+    if (Binding.hasCounterImplicitOrderID())
+      CreateMethod = lookupMethod(
+          ResourceDecl, "__createFromImplicitBindingWithImplicitCounter",
+          SC_Static);
+    else
+      CreateMethod =
+          lookupMethod(ResourceDecl, "__createFromImplicitBinding", SC_Static);
   }
   Args.add(RValue::get(Space), AST.UnsignedIntTy);
   Args.add(RValue::get(Range), AST.IntTy);
   Args.add(RValue::get(Index), AST.UnsignedIntTy);
   Args.add(RValue::get(NameStr), AST.getPointerType(AST.CharTy.withConst()));
+  if (Binding.hasCounterImplicitOrderID()) {
+    uint32_t CounterBinding = Binding.getCounterImplicitOrderID();
+    auto *CounterOrderID = llvm::ConstantInt::get(CGM.IntTy, CounterBinding);
+    Args.add(RValue::get(CounterOrderID), AST.UnsignedIntTy);
+  }
 
   return CreateMethod;
 }

clang/lib/Sema/HLSLBuiltinTypeDeclBuilder.cpp

@@ -144,6 +144,7 @@ struct BuiltinTypeMethodBuilder {
     _2,
     _3,
     _4,
+    _5,
     Handle = 128,
     CounterHandle,
     LastStmt
@@ -190,6 +191,9 @@ struct BuiltinTypeMethodBuilder {
   template <typename T>
   BuiltinTypeMethodBuilder &
   accessCounterHandleFieldOnResource(T ResourceRecord);
+  template <typename ResourceT, typename ValueT>
+  BuiltinTypeMethodBuilder &
+  setCounterHandleFieldOnResource(ResourceT ResourceRecord, ValueT HandleValue);
   template <typename T> BuiltinTypeMethodBuilder &returnValue(T ReturnValue);
   BuiltinTypeMethodBuilder &returnThis();
   BuiltinTypeDeclBuilder &finalize();
@@ -205,6 +209,11 @@ struct BuiltinTypeMethodBuilder {
     if (!Method)
       createDecl();
   }
+
+  template <typename ResourceT, typename ValueT>
+  BuiltinTypeMethodBuilder &setFieldOnResource(ResourceT ResourceRecord,
+                                               ValueT HandleValue,
+                                               FieldDecl *HandleField);
 };
 
 TemplateParameterListBuilder::~TemplateParameterListBuilder() {
@@ -592,13 +601,27 @@ template <typename ResourceT, typename ValueT>
 BuiltinTypeMethodBuilder &
 BuiltinTypeMethodBuilder::setHandleFieldOnResource(ResourceT ResourceRecord,
                                                    ValueT HandleValue) {
+  return setFieldOnResource(ResourceRecord, HandleValue,
+                            DeclBuilder.getResourceHandleField());
+}
+
+template <typename ResourceT, typename ValueT>
+BuiltinTypeMethodBuilder &
+BuiltinTypeMethodBuilder::setCounterHandleFieldOnResource(
+    ResourceT ResourceRecord, ValueT HandleValue) {
+  return setFieldOnResource(ResourceRecord, HandleValue,
+                            DeclBuilder.getResourceCounterHandleField());
+}
+
+template <typename ResourceT, typename ValueT>
+BuiltinTypeMethodBuilder &BuiltinTypeMethodBuilder::setFieldOnResource(
+    ResourceT ResourceRecord, ValueT HandleValue, FieldDecl *HandleField) {
   ensureCompleteDecl();
 
   Expr *ResourceExpr = convertPlaceholder(ResourceRecord);
   Expr *HandleValueExpr = convertPlaceholder(HandleValue);
 
   ASTContext &AST = DeclBuilder.SemaRef.getASTContext();
-  FieldDecl *HandleField = DeclBuilder.getResourceHandleField();
   MemberExpr *HandleMemberExpr = MemberExpr::CreateImplicit(
       AST, ResourceExpr, false, HandleField, HandleField->getType(), VK_LValue,
       OK_Ordinary);
@@ -829,6 +852,18 @@ BuiltinTypeDeclBuilder &BuiltinTypeDeclBuilder::addDefaultHandleConstructor() {
       .finalize();
 }
 
+BuiltinTypeDeclBuilder &
+BuiltinTypeDeclBuilder::addStaticInitializationFunctions(bool HasCounter) {
+  if (HasCounter) {
+    addCreateFromBindingWithImplicitCounter();
+    addCreateFromImplicitBindingWithImplicitCounter();
+  } else {
+    addCreateFromBinding();
+    addCreateFromImplicitBinding();
+  }
+  return *this;
+}
+
 // Adds static method that initializes resource from binding:
 //
 // static Resource<T> __createFromBinding(unsigned registerNo,
@@ -903,6 +938,73 @@ BuiltinTypeDeclBuilder &BuiltinTypeDeclBuilder::addCreateFromImplicitBinding() {
       .finalize();
 }
 
+BuiltinTypeDeclBuilder &
+BuiltinTypeDeclBuilder::addCreateFromBindingWithImplicitCounter() {
+  if (Record->isCompleteDefinition())
+    return *this;
+
+  using PH = BuiltinTypeMethodBuilder::PlaceHolder;
+  ASTContext &AST = SemaRef.getASTContext();
+  QualType HandleType = getResourceHandleField()->getType();
+  QualType RecordType = AST.getTypeDeclType(cast<TypeDecl>(Record));
+  BuiltinTypeMethodBuilder::LocalVar TmpVar("tmp", RecordType);
+
+  return BuiltinTypeMethodBuilder(*this,
+                                  "__createFromBindingWithImplicitCounter",
+                                  RecordType, false, false, SC_Static)
+      .addParam("registerNo", AST.UnsignedIntTy)
+      .addParam("spaceNo", AST.UnsignedIntTy)
+      .addParam("range", AST.IntTy)
+      .addParam("index", AST.UnsignedIntTy)
+      .addParam("name", AST.getPointerType(AST.CharTy.withConst()))
+      .addParam("counterOrderId", AST.UnsignedIntTy)
+      .declareLocalVar(TmpVar)
+      .accessHandleFieldOnResource(TmpVar)
+      .callBuiltin("__builtin_hlsl_resource_handlefrombinding", HandleType,
+                   PH::LastStmt, PH::_0, PH::_1, PH::_2, PH::_3, PH::_4)
+      .setHandleFieldOnResource(TmpVar, PH::LastStmt)
+      .accessHandleFieldOnResource(TmpVar)
+      .callBuiltin("__builtin_hlsl_resource_counterhandlefromimplicitbinding",
+                   HandleType, PH::LastStmt, PH::_5, PH::_1)
+      .setCounterHandleFieldOnResource(TmpVar, PH::LastStmt)
+      .returnValue(TmpVar)
+      .finalize();
+}
+
+BuiltinTypeDeclBuilder &
+BuiltinTypeDeclBuilder::addCreateFromImplicitBindingWithImplicitCounter() {
+  if (Record->isCompleteDefinition())
+    return *this;
+
+  using PH = BuiltinTypeMethodBuilder::PlaceHolder;
+  ASTContext &AST = SemaRef.getASTContext();
+  QualType HandleType = getResourceHandleField()->getType();
+  QualType RecordType = AST.getTypeDeclType(cast<TypeDecl>(Record));
+  BuiltinTypeMethodBuilder::LocalVar TmpVar("tmp", RecordType);
+
+  return BuiltinTypeMethodBuilder(
+             *this, "__createFromImplicitBindingWithImplicitCounter",
+             RecordType, false, false, SC_Static)
+      .addParam("orderId", AST.UnsignedIntTy)
+      .addParam("spaceNo", AST.UnsignedIntTy)
+      .addParam("range", AST.IntTy)
+      .addParam("index", AST.UnsignedIntTy)
+      .addParam("name", AST.getPointerType(AST.CharTy.withConst()))
+      .addParam("counterOrderId", AST.UnsignedIntTy)
+      .declareLocalVar(TmpVar)
+      .accessHandleFieldOnResource(TmpVar)
+      .callBuiltin("__builtin_hlsl_resource_handlefromimplicitbinding",
+                   HandleType, PH::LastStmt, PH::_0, PH::_1, PH::_2, PH::_3,
+                   PH::_4)
+      .setHandleFieldOnResource(TmpVar, PH::LastStmt)
+      .accessHandleFieldOnResource(TmpVar)
+      .callBuiltin("__builtin_hlsl_resource_counterhandlefromimplicitbinding",
+                   HandleType, PH::LastStmt, PH::_5, PH::_1)
+      .setCounterHandleFieldOnResource(TmpVar, PH::LastStmt)
+      .returnValue(TmpVar)
+      .finalize();
+}
+
 BuiltinTypeDeclBuilder &BuiltinTypeDeclBuilder::addCopyConstructor() {
   assert(!Record->isCompleteDefinition() && "record is already complete");
 
@@ -1048,7 +1150,7 @@ BuiltinTypeDeclBuilder &BuiltinTypeDeclBuilder::addIncrementCounterMethod() {
   return BuiltinTypeMethodBuilder(*this, "IncrementCounter",
                                   SemaRef.getASTContext().UnsignedIntTy)
       .callBuiltin("__builtin_hlsl_buffer_update_counter", QualType(),
-                   PH::Handle, getConstantIntExpr(1))
+                   PH::CounterHandle, getConstantIntExpr(1))
       .finalize();
 }
 
@@ -1057,7 +1159,7 @@ BuiltinTypeDeclBuilder &BuiltinTypeDeclBuilder::addDecrementCounterMethod() {
   return BuiltinTypeMethodBuilder(*this, "DecrementCounter",
                                   SemaRef.getASTContext().UnsignedIntTy)
       .callBuiltin("__builtin_hlsl_buffer_update_counter", QualType(),
-                   PH::Handle, getConstantIntExpr(-1))
+                   PH::CounterHandle, getConstantIntExpr(-1))
       .finalize();
 }
 
@@ -1102,7 +1204,7 @@ BuiltinTypeDeclBuilder &BuiltinTypeDeclBuilder::addAppendMethod() {
   return BuiltinTypeMethodBuilder(*this, "Append", AST.VoidTy)
       .addParam("value", ElemTy)
       .callBuiltin("__builtin_hlsl_buffer_update_counter", AST.UnsignedIntTy,
-                   PH::Handle, getConstantIntExpr(1))
+                   PH::CounterHandle, getConstantIntExpr(1))
       .callBuiltin("__builtin_hlsl_resource_getpointer",
                    AST.getPointerType(AddrSpaceElemTy), PH::Handle,
                    PH::LastStmt)
@@ -1119,7 +1221,7 @@ BuiltinTypeDeclBuilder &BuiltinTypeDeclBuilder::addConsumeMethod() {
       AST.getAddrSpaceQualType(ElemTy, LangAS::hlsl_device);
   return BuiltinTypeMethodBuilder(*this, "Consume", ElemTy)
       .callBuiltin("__builtin_hlsl_buffer_update_counter", AST.UnsignedIntTy,
-                   PH::Handle, getConstantIntExpr(-1))
+                   PH::CounterHandle, getConstantIntExpr(-1))
       .callBuiltin("__builtin_hlsl_resource_getpointer",
                    AST.getPointerType(AddrSpaceElemTy), PH::Handle,
                    PH::LastStmt)

clang/lib/Sema/HLSLBuiltinTypeDeclBuilder.h

@@ -83,8 +83,7 @@ class BuiltinTypeDeclBuilder {
   BuiltinTypeDeclBuilder &addCopyAssignmentOperator();
 
   // Static create methods
-  BuiltinTypeDeclBuilder &addCreateFromBinding();
-  BuiltinTypeDeclBuilder &addCreateFromImplicitBinding();
+  BuiltinTypeDeclBuilder &addStaticInitializationFunctions(bool HasCounter);
 
   // Builtin types methods
   BuiltinTypeDeclBuilder &addLoadMethods();
@@ -96,6 +95,10 @@ class BuiltinTypeDeclBuilder {
   BuiltinTypeDeclBuilder &addConsumeMethod();
 
 private:
+  BuiltinTypeDeclBuilder &addCreateFromBinding();
+  BuiltinTypeDeclBuilder &addCreateFromImplicitBinding();
+  BuiltinTypeDeclBuilder &addCreateFromBindingWithImplicitCounter();
+  BuiltinTypeDeclBuilder &addCreateFromImplicitBindingWithImplicitCounter();
   BuiltinTypeDeclBuilder &addResourceMember(StringRef MemberName,
                                             ResourceClass RC, bool IsROV,
                                             bool RawBuffer, bool IsCounter,

clang/lib/Sema/HLSLExternalSemaSource.cpp

@@ -236,8 +236,7 @@ static BuiltinTypeDeclBuilder setupBufferType(CXXRecordDecl *Decl, Sema &S,
       .addDefaultHandleConstructor()
       .addCopyConstructor()
       .addCopyAssignmentOperator()
-      .addCreateFromBinding()
-      .addCreateFromImplicitBinding();
+      .addStaticInitializationFunctions(HasCounter);
 }
 
 // This function is responsible for constructing the constraint expression for