[DirectX] Add `llvm.dx.resource.getdimensions.x` intrinsic and lowering to DXIL (#161753)
Introduces LLVM intrinsic `llvm.dx.resource.getdimensions.x` and its lowering to DXIL op `op.dx.getDimensions`.
The intrinsic will be used to implement `GetDimension` for buffers. The lowering is using `undef` value since it is required by the DXIL format which is based on LLVM 3.7.
Proposal update: https://github.com/llvm/wg-hlsl/pull/350
Closes #112982
diff --git a/llvm/docs/DirectX/DXILResources.rst b/llvm/docs/DirectX/DXILResources.rst
index 91dcd5c8..f253e02f 100644
--- a/llvm/docs/DirectX/DXILResources.rst
+++ b/llvm/docs/DirectX/DXILResources.rst
@@ -746,3 +746,92 @@
@llvm.dx.resource.load.cbufferrow.8(
target("dx.CBuffer", target("dx.Layout", {i16}, 2, 0)) %buffer,
i32 %index)
+
+Resource dimensions
+-------------------
+
+*relevant types: Textures and Buffer*
+
+The `getDimensions`_ DXIL operation returns the dimensions of a texture or
+buffer resource. It returns a `Dimensions`_ type, which is a struct
+containing four ``i32`` values. The values in the struct represent the size
+of each dimension of the resource, and when aplicable the number of array
+elements or number of samples. The mapping is defined in the
+`getDimensions`_ documentation.
+
+The LLVM IR representation of this operation has several forms
+depending on the resource type and the specific ``getDimensions`` query.
+The intrinsics return a scalar or anonymous struct with up to 4 `i32`
+elements. The intrinsic names include suffixes to indicate the number of
+elements in the return value. The suffix `.x` indicates a single `i32`
+return value, `.xy` indicates a struct with two `i32` values, and `.xyz`
+indicates a struct with three `i32` values.
+
+Intrinsics representing queries on multisampled texture resources include
+`.ms.` in their name and their return value includes an additional `i32` for
+the number of samples.
+
+Intrinsics with `mip_level` argument and `.levels.` in their name are used
+for texture resources with multiple MIP levels. Their return
+struct includes an additional `i32` for the number of levels the resource has.
+
+.. code-block:: llvm
+
+ i32 @llvm.dx.resource.getdimensions.x( target("dx.*") handle )
+ {i32, i32} @llvm.dx.resource.getdimensions.xy( target("dx.*") handle )
+ {i32, i32, i32} @llvm.dx.resource.getdimensions.xyz( target("dx.*") handle )
+ {i32, i32} @llvm.dx.resource.getdimensions.levels.x( target("dx.*") handle, i32 mip_level )
+ {i32, i32, i32} @llvm.dx.resource.getdimensions.levels.xy( target("dx.*") handle, i32 mip_level )
+ {i32, i32, i32, i32} @llvm.dx.resource.getdimensions.levels.xyz( target("dx.*") handle, i32 mip_level )
+ {i32, i32, i32} @llvm.dx.resource.getdimensions.ms.xy( target("dx.*") handle )
+ {i32, i32, i32, i32} @llvm.dx.resource.getdimensions.ms.xyz( target("dx.*") handle )
+
+.. list-table:: ``@llvm.dx.resource.getdimensions.*``
+ :header-rows: 1
+
+ * - Argument
+ -
+ - Type
+ - Description
+ * - Return value
+ -
+ - `i32`, `{i32, i32}`, `{i32, i32, i32}`, or `{i32, i32, i32, i32}`
+ - Width, height, and depth of the resource (based on the specific suffix), and a number of levels or samples where aplicable.
+ * - ``%handle``
+ - 0
+ - ``target(dx.*)``
+ - Resource handle
+ * - ``%mip_level``
+ - 1
+ - ``i32``
+ - MIP level for the requested dimensions.
+
+Examples:
+
+.. code-block:: llvm
+
+ ; RWBuffer<float4>
+ %dim = call i32 @llvm.dx.resource.getdimensions.x(target("dx.TypedBuffer", <4 x float>, 1, 0, 0) %handle)
+
+ ; Texture2D
+ %0 = call {i32, i32} @llvm.dx.resource.getdimensions.xy(target("dx.Texture", ...) %tex2d)
+ %tex2d_width = extractvalue {i32, i32} %0, 0
+ %tex2d_height = extractvalue {i32, i32} %0, 1
+
+ ; Texture2DArray with levels
+ %1 = call {i32, i32, i32, i32} @llvm.dx.resource.getdimensions.levels.xyz(
+ target("dx.Texture", ...) %tex2darray, i32 1)
+ %tex2darray_width = extractvalue {i32, i32, i32, i32} %1, 0
+ %tex2darray_height = extractvalue {i32, i32, i32, i32} %1, 1
+ %tex2darray_elem_count = extractvalue {i32, i32, i32, i32} %1, 2
+ %tex2darray_levels_count = extractvalue {i32, i32, i32, i32} %1, 3
+
+ ; Texture2DMS
+ %2 = call {i32, i32, i32} @llvm.dx.resource.getdimensions.ms.xy(
+ target("dx.Texture", ...) %tex2dms)
+ %tex2dms_width = extractvalue {i32, i32, i32} %2, 0
+ %tex2dms_height = extractvalue {i32, i32, i32} %2, 1
+ %tex2dms_samples_count = extractvalue {i32, i32, i32} %2, 2
+
+.. _Dimensions: https://github.com/microsoft/DirectXShaderCompiler/blob/main/docs/DXIL.rst#resource-operation-return-types
+.. _getDimensions: https://github.com/microsoft/DirectXShaderCompiler/blob/main/docs/DXIL.rst#getdimensions
diff --git a/llvm/include/llvm/IR/IntrinsicsDirectX.td b/llvm/include/llvm/IR/IntrinsicsDirectX.td
index 570d6bc..3b7077c 100644
--- a/llvm/include/llvm/IR/IntrinsicsDirectX.td
+++ b/llvm/include/llvm/IR/IntrinsicsDirectX.td
@@ -77,6 +77,9 @@
: DefaultAttrsIntrinsic<[llvm_i32_ty], [llvm_any_ty, llvm_i8_ty],
[IntrInaccessibleMemOrArgMemOnly]>;
+def int_dx_resource_getdimensions_x
+ : DefaultAttrsIntrinsic<[llvm_i32_ty], [llvm_any_ty], [IntrReadMem]>;
+
// Cast between target extension handle types and dxil-style opaque handles
def int_dx_resource_casthandle : Intrinsic<[llvm_any_ty], [llvm_any_ty]>;
diff --git a/llvm/include/llvm/IR/IntrinsicsSPIRV.td b/llvm/include/llvm/IR/IntrinsicsSPIRV.td
index 66e24fa..49a182be 100644
--- a/llvm/include/llvm/IR/IntrinsicsSPIRV.td
+++ b/llvm/include/llvm/IR/IntrinsicsSPIRV.td
@@ -167,6 +167,9 @@
: DefaultAttrsIntrinsic<[llvm_i32_ty], [llvm_any_ty, llvm_i8_ty],
[IntrInaccessibleMemOrArgMemOnly]>;
+ def int_spv_resource_getdimensions_x
+ : DefaultAttrsIntrinsic<[llvm_i32_ty], [llvm_any_ty], [IntrReadMem]>;
+
def int_spv_resource_getpointer
: DefaultAttrsIntrinsic<[llvm_anyptr_ty], [llvm_any_ty, llvm_i32_ty],
[IntrNoMem]>;
diff --git a/llvm/lib/Target/DirectX/DXIL.td b/llvm/lib/Target/DirectX/DXIL.td
index 228114c..44c4830 100644
--- a/llvm/lib/Target/DirectX/DXIL.td
+++ b/llvm/lib/Target/DirectX/DXIL.td
@@ -57,6 +57,7 @@
def ResPropsTy : DXILOpParamType;
def SplitDoubleTy : DXILOpParamType;
def BinaryWithCarryTy : DXILOpParamType;
+def DimensionsTy : DXILOpParamType;
class DXILOpClass;
@@ -901,6 +902,13 @@
let attributes = [Attributes<DXIL1_0, [ReadOnly]>];
}
+def GetDimensions : DXILOp<72, getDimensions> {
+ let Doc = "gets the dimensions of a buffer or texture";
+ let arguments = [HandleTy, Int32Ty];
+ let result = DimensionsTy;
+ let stages = [Stages<DXIL1_0, [all_stages]>];
+}
+
def Barrier : DXILOp<80, barrier> {
let Doc = "inserts a memory barrier in the shader";
let intrinsics = [
diff --git a/llvm/lib/Target/DirectX/DXILOpBuilder.cpp b/llvm/lib/Target/DirectX/DXILOpBuilder.cpp
index 1aed8f9..944b2e6 100644
--- a/llvm/lib/Target/DirectX/DXILOpBuilder.cpp
+++ b/llvm/lib/Target/DirectX/DXILOpBuilder.cpp
@@ -261,6 +261,12 @@
return StructType::create({Int32Ty, Int1Ty}, "dx.types.i32c");
}
+static StructType *getDimensionsType(LLVMContext &Ctx) {
+ Type *Int32Ty = Type::getInt32Ty(Ctx);
+ return getOrCreateStructType("dx.types.Dimensions",
+ {Int32Ty, Int32Ty, Int32Ty, Int32Ty}, Ctx);
+}
+
static Type *getTypeFromOpParamType(OpParamType Kind, LLVMContext &Ctx,
Type *OverloadTy) {
switch (Kind) {
@@ -318,6 +324,8 @@
return getSplitDoubleType(Ctx);
case OpParamType::BinaryWithCarryTy:
return getBinaryWithCarryType(Ctx);
+ case OpParamType::DimensionsTy:
+ return getDimensionsType(Ctx);
}
llvm_unreachable("Invalid parameter kind");
return nullptr;
diff --git a/llvm/lib/Target/DirectX/DXILOpLowering.cpp b/llvm/lib/Target/DirectX/DXILOpLowering.cpp
index 610d8b6..e46a393 100644
--- a/llvm/lib/Target/DirectX/DXILOpLowering.cpp
+++ b/llvm/lib/Target/DirectX/DXILOpLowering.cpp
@@ -627,6 +627,28 @@
});
}
+ [[nodiscard]] bool lowerGetDimensionsX(Function &F) {
+ IRBuilder<> &IRB = OpBuilder.getIRB();
+ Type *Int32Ty = IRB.getInt32Ty();
+
+ return replaceFunction(F, [&](CallInst *CI) -> Error {
+ IRB.SetInsertPoint(CI);
+ Value *Handle =
+ createTmpHandleCast(CI->getArgOperand(0), OpBuilder.getHandleType());
+ Value *Undef = UndefValue::get(Int32Ty);
+
+ Expected<CallInst *> OpCall = OpBuilder.tryCreateOp(
+ OpCode::GetDimensions, {Handle, Undef}, CI->getName(), Int32Ty);
+ if (Error E = OpCall.takeError())
+ return E;
+ Value *Dim = IRB.CreateExtractValue(*OpCall, 0);
+
+ CI->replaceAllUsesWith(Dim);
+ CI->eraseFromParent();
+ return Error::success();
+ });
+ }
+
[[nodiscard]] bool lowerGetPointer(Function &F) {
// These should have already been handled in DXILResourceAccess, so we can
// just clean up the dead prototype.
@@ -934,6 +956,9 @@
case Intrinsic::dx_resource_updatecounter:
HasErrors |= lowerUpdateCounter(F);
break;
+ case Intrinsic::dx_resource_getdimensions_x:
+ HasErrors |= lowerGetDimensionsX(F);
+ break;
case Intrinsic::ctpop:
HasErrors |= lowerCtpopToCountBits(F);
break;
diff --git a/llvm/test/CodeGen/DirectX/bufferGetDimensions.ll b/llvm/test/CodeGen/DirectX/bufferGetDimensions.ll
new file mode 100644
index 0000000..ff03bf1
--- /dev/null
+++ b/llvm/test/CodeGen/DirectX/bufferGetDimensions.ll
@@ -0,0 +1,16 @@
+; RUN: opt -S -dxil-op-lower %s | FileCheck %s
+
+target triple = "dxil-pc-shadermodel6.6-compute"
+
+define i32 @test_getdimensions_no_mips() {
+ ; CHECK: %[[HANDLE:.*]] = call %dx.types.Handle @dx.op.createHandleFromBinding(i32 217,
+ ; CHECK-NEXT: %[[ANNOT_HANDLE:.*]] = call %dx.types.Handle @dx.op.annotateHandle(i32 216, %dx.types.Handle %[[HANDLE]]
+ %handle = call target("dx.TypedBuffer", <4 x float>, 0, 0, 0) @llvm.dx.resource.handlefrombinding(i32 0, i32 0, i32 1, i32 0, ptr null)
+
+ ; CHECK-NEXT: %[[RETVAL:.*]] = call %dx.types.Dimensions @dx.op.getDimensions(i32 72, %dx.types.Handle %[[ANNOT_HANDLE]], i32 undef)
+ ; CHECK-NEXT: %[[DIM:.*]] = extractvalue %dx.types.Dimensions %[[RETVAL]], 0
+ %1 = call i32 @llvm.dx.resource.getdimensions.x(target("dx.TypedBuffer", <4 x float>, 0, 0, 0) %handle)
+
+ ; CHECK-NEXT: ret i32 %[[DIM]]
+ ret i32 %1
+}
