[DirectX] Lower @llvm.dx.handle.fromBinding to DXIL ops

The `@llvm.dx.handle.fromBinding` intrinsic is lowered either to the
`CreateHandle` op or a pair of `CreateHandleFromBinding` and `AnnotateHandle`
ops, depending on the DXIL version. Regardless of the DXIL version we need to
emit metadata about the binding, but that's left to a separate change.

These DXIL ops all need to return the `%dx.types.Handle` type, but the llvm
intrinsic returns a target extension type. To facilitate changing the type of
the operation and all of its users, we introduce `%llvm.dx.cast.handle`, which
can cast between the two handle representations.

Pull Request: llvm#104251

Author: bogner

llvm/docs/DirectX/DXILResources.rst

@@ -162,6 +162,10 @@ the subsequent ``dx.op.annotateHandle`` operation in. Note that we don't have
 an analogue for `dx.op.createHandle`_, since ``dx.op.createHandleFromBinding``
 subsumes it.
 
+For simplicity of lowering, we match DXIL in using an index from the beginning
+of the binding space rather than an index from the lower bound of the binding
+itself.
+
 .. _dx.op.createHandle: https://github.com/microsoft/DirectXShaderCompiler/blob/main/docs/DXIL.rst#resource-handles
 
 .. list-table:: ``@llvm.dx.handle.fromBinding``
@@ -190,7 +194,7 @@ subsumes it.
    * - ``%index``
      - 4
      - ``i32``
-     - Index of the resource to access.
+     - Index from the beginning of the binding space to access.
    * - ``%non-uniform``
      - 5
      - i1

llvm/include/llvm/IR/IntrinsicsDirectX.td

@@ -30,6 +30,9 @@ def int_dx_handle_fromBinding
           [llvm_i32_ty, llvm_i32_ty, llvm_i32_ty, llvm_i32_ty, llvm_i1_ty],
           [IntrNoMem]>;
 
+// Cast between target extension handle types and dxil-style opaque handles
+def int_dx_cast_handle : Intrinsic<[llvm_any_ty], [llvm_any_ty]>;
+
 def int_dx_all : DefaultAttrsIntrinsic<[llvm_i1_ty], [llvm_any_ty]>;
 def int_dx_any : DefaultAttrsIntrinsic<[llvm_i1_ty], [llvm_any_ty]>;
 def int_dx_clamp : DefaultAttrsIntrinsic<[llvm_any_ty], [LLVMMatchType<0>, LLVMMatchType<0>, LLVMMatchType<0>]>;

llvm/lib/Target/DirectX/DXIL.td

@@ -42,6 +42,8 @@ def FloatTy : DXILOpParamType;
 def DoubleTy : DXILOpParamType;
 def ResRetTy : DXILOpParamType;
 def HandleTy : DXILOpParamType;
+def ResBindTy : DXILOpParamType;
+def ResPropsTy : DXILOpParamType;
 
 class DXILOpClass;
 
@@ -683,6 +685,14 @@ def Dot4 :  DXILOp<56, dot4> {
   let attributes = [Attributes<DXIL1_0, [ReadNone]>];
 }
 
+def CreateHandle : DXILOp<57, createHandle> {
+  let Doc = "creates the handle to a resource";
+  // ResourceClass, RangeID, Index, NonUniform
+  let arguments = [Int8Ty, Int32Ty, Int32Ty, Int1Ty];
+  let result = HandleTy;
+  let stages = [Stages<DXIL1_0, [all_stages]>, Stages<DXIL1_6, [removed]>];
+}
+
 def ThreadId :  DXILOp<93, threadId> {
   let Doc = "Reads the thread ID";
   let LLVMIntrinsic = int_dx_thread_id;
@@ -722,3 +732,17 @@ def FlattenedThreadIdInGroup :  DXILOp<96, flattenedThreadIdInGroup> {
   let stages = [Stages<DXIL1_0, [compute, mesh, amplification, node]>];
   let attributes = [Attributes<DXIL1_0, [ReadNone]>];
 }
+
+def AnnotateHandle : DXILOp<217, annotateHandle> {
+  let Doc = "annotate handle with resource properties";
+  let arguments = [HandleTy, ResPropsTy];
+  let result = HandleTy;
+  let stages = [Stages<DXIL1_6, [all_stages]>];
+}
+
+def CreateHandleFromBinding : DXILOp<218, createHandleFromBinding> {
+  let Doc = "create resource handle from binding";
+  let arguments = [ResBindTy, Int32Ty, Int1Ty];
+  let result = HandleTy;
+  let stages = [Stages<DXIL1_6, [all_stages]>];
+}

llvm/lib/Target/DirectX/DXILOpBuilder.cpp

@@ -208,6 +208,23 @@ static StructType *getHandleType(LLVMContext &Ctx) {
                                Ctx);
 }
 
+static StructType *getResBindType(LLVMContext &Context) {
+  if (auto *ST = StructType::getTypeByName(Context, "dx.types.ResBind"))
+    return ST;
+  Type *Int32Ty = Type::getInt32Ty(Context);
+  Type *Int8Ty = Type::getInt8Ty(Context);
+  return StructType::create({Int32Ty, Int32Ty, Int32Ty, Int8Ty},
+                            "dx.types.ResBind");
+}
+
+static StructType *getResPropsType(LLVMContext &Context) {
+  if (auto *ST =
+          StructType::getTypeByName(Context, "dx.types.ResourceProperties"))
+    return ST;
+  Type *Int32Ty = Type::getInt32Ty(Context);
+  return StructType::create({Int32Ty, Int32Ty}, "dx.types.ResourceProperties");
+}
+
 static Type *getTypeFromOpParamType(OpParamType Kind, LLVMContext &Ctx,
                                     Type *OverloadTy) {
   switch (Kind) {
@@ -235,6 +252,10 @@ static Type *getTypeFromOpParamType(OpParamType Kind, LLVMContext &Ctx,
     return getResRetType(OverloadTy, Ctx);
   case OpParamType::HandleTy:
     return getHandleType(Ctx);
+  case OpParamType::ResBindTy:
+    return getResBindType(Ctx);
+  case OpParamType::ResPropsTy:
+    return getResPropsType(Ctx);
   }
   llvm_unreachable("Invalid parameter kind");
   return nullptr;
@@ -430,6 +451,29 @@ CallInst *DXILOpBuilder::createOp(dxil::OpCode OpCode, ArrayRef<Value *> Args,
   return *Result;
 }
 
+StructType *DXILOpBuilder::getHandleType() {
+  return ::getHandleType(IRB.getContext());
+}
+
+Constant *DXILOpBuilder::getResBind(uint32_t LowerBound, uint32_t UpperBound,
+                                    uint32_t SpaceID, dxil::ResourceClass RC) {
+  Type *Int32Ty = IRB.getInt32Ty();
+  Type *Int8Ty = IRB.getInt8Ty();
+  return ConstantStruct::get(
+      getResBindType(IRB.getContext()),
+      {ConstantInt::get(Int32Ty, LowerBound),
+       ConstantInt::get(Int32Ty, UpperBound),
+       ConstantInt::get(Int32Ty, SpaceID),
+       ConstantInt::get(Int8Ty, llvm::to_underlying(RC))});
+}
+
+Constant *DXILOpBuilder::getResProps(uint32_t Word0, uint32_t Word1) {
+  Type *Int32Ty = IRB.getInt32Ty();
+  return ConstantStruct::get(
+      getResPropsType(IRB.getContext()),
+      {ConstantInt::get(Int32Ty, Word0), ConstantInt::get(Int32Ty, Word1)});
+}
+
 const char *DXILOpBuilder::getOpCodeName(dxil::OpCode DXILOp) {
   return ::getOpCodeName(DXILOp);
 }

llvm/lib/Target/DirectX/DXILOpBuilder.h

@@ -15,13 +15,15 @@
 #include "DXILConstants.h"
 #include "llvm/ADT/SmallVector.h"
 #include "llvm/IR/IRBuilder.h"
+#include "llvm/Support/DXILABI.h"
 #include "llvm/Support/Error.h"
 #include "llvm/TargetParser/Triple.h"
 
 namespace llvm {
 class Module;
 class IRBuilderBase;
 class CallInst;
+class Constant;
 class Value;
 class Type;
 class FunctionType;
@@ -44,6 +46,15 @@ class DXILOpBuilder {
   Expected<CallInst *> tryCreateOp(dxil::OpCode Op, ArrayRef<Value *> Args,
                                    Type *RetTy = nullptr);
 
+  /// Get the `%dx.types.Handle` type.
+  StructType *getHandleType();
+
+  /// Get a constant `%dx.types.ResBind` value.
+  Constant *getResBind(uint32_t LowerBound, uint32_t UpperBound,
+                       uint32_t SpaceID, dxil::ResourceClass RC);
+  /// Get a constant `%dx.types.ResourceProperties` value.
+  Constant *getResProps(uint32_t Word0, uint32_t Word1);
+
   /// Return the name of the given opcode.
   static const char *getOpCodeName(dxil::OpCode DXILOp);