[SPIR-V][vk::SampledTexture] #4. Add .Load() methods for vk::SampledTexture2D type. (microsoft#8096)

Part of microsoft#7979

Implement `Load()` methods for `vk::SampledTexture2D`:
```hlsl
ParamType Load(int3 location, [], [ParamType offset], [uint status]);
```
Please see the last commit.

Author: luciechoi

tools/clang/lib/SPIRV/SpirvEmitter.cpp

@@ -4693,9 +4693,11 @@ SpirvInstruction *SpirvEmitter::processBufferTextureLoad(
   // The result type of an OpImageFetch must be a vec4 of float or int.
   const auto type = object->getType();
   assert(isBuffer(type) || isRWBuffer(type) || isTexture(type) ||
-         isRWTexture(type) || isSubpassInput(type) || isSubpassInputMS(type));
+         isRWTexture(type) || isSubpassInput(type) || isSubpassInputMS(type) ||
+         isSampledTexture(type));
 
-  const bool doFetch = isBuffer(type) || isTexture(type);
+  const bool doFetch =
+      isBuffer(type) || isTexture(type) || isSampledTexture(type);
   const bool rasterizerOrdered = isRasterizerOrderedView(type);
 
   if (rasterizerOrdered) {
@@ -4759,6 +4761,18 @@ SpirvInstruction *SpirvEmitter::processBufferTextureLoad(
 
   // OpImageFetch and OpImageRead can only fetch a vector of 4 elements.
   const QualType texelType = astContext.getExtVectorType(elemType, 4u);
+
+  if (isSampledTexture(type)) {
+    LowerTypeVisitor lowerTypeVisitor(astContext, spvContext, spirvOptions,
+                                      spvBuilder);
+    const SpirvType *spvType = lowerTypeVisitor.lowerType(
+        type, SpirvLayoutRule::Void, llvm::None, loc);
+    // Get image type based on type, assuming type is a sampledimage type
+    const auto *sampledImageType = cast<SampledImageType>(spvType);
+    const SpirvType *imgType = sampledImageType->getImageType();
+    objectInfo =
+        spvBuilder.createUnaryOp(spv::Op::OpImage, imgType, objectInfo, loc);
+  }
   auto *texel = spvBuilder.createImageFetchOrRead(
       doFetch, texelType, type, objectInfo, location, lod, constOffset,
       /*constOffsets*/ nullptr, sampleNumber, residencyCode, loc, range);
@@ -6345,7 +6359,8 @@ SpirvEmitter::processTextureSampleCmpLevel(const CXXMemberCallExpr *expr) {
 SpirvInstruction *
 SpirvEmitter::processBufferTextureLoad(const CXXMemberCallExpr *expr) {
   // Signature:
-  // For Texture1D, Texture1DArray, Texture2D, Texture2DArray, Texture3D:
+  // For Texture1D, Texture1DArray, Texture2D, Texture2DArray, Texture3D
+  // and their SampledTexture variants:
   // ret Object.Load(int Location
   //                 [, int Offset]
   //                 [, uint status]);
@@ -6403,7 +6418,7 @@ SpirvEmitter::processBufferTextureLoad(const CXXMemberCallExpr *expr) {
   // and 1 for location.
   const bool hasOffsetArg = numArgs - hasStatusArg - textureMS - 1 > 0;
 
-  if (isTexture(objectType)) {
+  if (isTexture(objectType) || isSampledTexture(objectType)) {
     // .Load() has a second optional paramter for offset.
     SpirvInstruction *location = doExpr(locationArg);
     SpirvInstruction *constOffset = nullptr, *varOffset = nullptr;

tools/clang/test/CodeGenSPIRV/vk.sampledtexture.load.hlsl

@@ -0,0 +1,48 @@
+// RUN: %dxc -T ps_6_0 -E main -fcgl  %s -spirv | FileCheck %s
+
+
+vk::SampledTexture2D<float4> tex2D_F4 : register(t1);
+
+// CHECK: OpCapability SparseResidency
+
+// CHECK: [[v2ic:%[0-9]+]] = OpConstantComposite %v2int %int_1 %int_2
+
+// CHECK: %SparseResidencyStruct = OpTypeStruct %uint %v4float
+
+float4 main(int3 location: A) : SV_Target {
+    uint status;
+
+// CHECK:        [[loc:%[0-9]+]] = OpLoad %v3int %location
+// CHECK-NEXT: [[coord_0:%[0-9]+]] = OpVectorShuffle %v2int [[loc]] [[loc]] 0 1
+// CHECK-NEXT:   [[lod_0:%[0-9]+]] = OpCompositeExtract %int [[loc]] 2
+// CHECK-NEXT:    [[tex:%[0-9]+]] = OpLoad %type_sampled_image %tex2D_F4
+// CHECK-NEXT:    [[tex_img:%[0-9]+]] = OpImage %type_2d_image [[tex]]
+// CHECK-NEXT:       {{%[0-9]+}} = OpImageFetch %v4float [[tex_img]] [[coord_0]] Lod [[lod_0]]
+    float4 val1 = tex2D_F4.Load(location);
+
+// CHECK:        [[loc:%[0-9]+]] = OpLoad %v3int %location
+// CHECK-NEXT: [[coord_0:%[0-9]+]] = OpVectorShuffle %v2int [[loc]] [[loc]] 0 1
+// CHECK-NEXT:   [[lod_0:%[0-9]+]] = OpCompositeExtract %int [[loc]] 2
+// CHECK-NEXT:    [[tex:%[0-9]+]] = OpLoad %type_sampled_image %tex2D_F4
+// CHECK-NEXT:    [[tex_img:%[0-9]+]] = OpImage %type_2d_image [[tex]]
+// CHECK-NEXT:       {{%[0-9]+}} = OpImageFetch %v4float [[tex_img]] [[coord_0]] Lod|ConstOffset [[lod_0]] [[v2ic]]
+    float4 val2 = tex2D_F4.Load(location, int2(1, 2));
+
+/////////////////////////////////
+/// Using the Status argument ///
+/////////////////////////////////
+
+// CHECK:        [[loc:%[0-9]+]] = OpLoad %v3int %location
+// CHECK-NEXT: [[coord_0:%[0-9]+]] = OpVectorShuffle %v2int [[loc]] [[loc]] 0 1
+// CHECK-NEXT:   [[lod_0:%[0-9]+]] = OpCompositeExtract %int [[loc]] 2
+// CHECK-NEXT:    [[tex:%[0-9]+]] = OpLoad %type_sampled_image %tex2D_F4
+// CHECK-NEXT:    [[tex_img:%[0-9]+]] = OpImage %type_2d_image [[tex]]
+// CHECK-NEXT:[[structResult:%[0-9]+]] = OpImageSparseFetch %SparseResidencyStruct [[tex_img]] [[coord_0]] Lod|ConstOffset [[lod_0]] [[v2ic]]
+// CHECK-NEXT:      [[status:%[0-9]+]] = OpCompositeExtract %uint [[structResult]] 0
+// CHECK-NEXT:                        OpStore %status [[status]]
+// CHECK-NEXT:    [[v4result:%[0-9]+]] = OpCompositeExtract %v4float [[structResult]] 1
+// CHECK-NEXT:                        OpStore %val3 [[v4result]]
+    float4  val3 = tex2D_F4.Load(location, int2(1, 2), status);
+
+    return 1.0;
+}

utils/hct/gen_intrin_main.txt

@@ -1242,4 +1242,7 @@ namespace VkSampledTexture2DMethods {
     void [[]] GetDimensions(in uint x, out float_like width, out $type2 height, out $type2 levels) : resinfo;
     void [[]] GetDimensions(out uint_only width, out $type1 height) : resinfo_uint_o;
     void [[]] GetDimensions(out float_like width, out $type1 height) : resinfo_o;
+    $classT [[ro]] Load(in int<3> x) : tex2d_t_load;
+    $classT [[ro]] Load(in int<3> x, in int<2> o) : tex2d_t_load_o;
+    $classT [[]] Load(in int<3> x, in int<2> o, out uint_only status) : tex2d_t_load_o_s;
 } namespace