[SPIR-V] Add vk::SampledTexture2D resource type and .Sample(), .CalculateLevelOfDetail() method. (microsoft#8047)

Part of microsoft#7979
- Add `SampledTexture2D` resource type in the `vk` namespace.
- Add `.Sample(float2 location)` method.
- Add default type parameter `float4`.
- Allow optional arguments `int2 offset, float clamp, uint status`.
- Add `.CalculateLevelOfDetail(float2 location)` method.

Author: luciechoi

include/dxc/dxcapi.internal.h

@@ -140,7 +140,8 @@ enum LEGAL_INTRINSIC_COMPTYPES {
 
 #ifdef ENABLE_SPIRV_CODEGEN
   LICOMPTYPE_VK_BUFFER_POINTER = 56,
-  LICOMPTYPE_COUNT = 57
+  LICOMPTYPE_VK_SAMPLED_TEXTURE2D = 57,
+  LICOMPTYPE_COUNT = 58
 #else
   LICOMPTYPE_COUNT = 56
 #endif

tools/clang/include/clang/AST/HlslTypes.h

@@ -407,6 +407,10 @@ clang::CXXRecordDecl *
 DeclareVkBufferPointerType(clang::ASTContext &context,
                            clang::DeclContext *declContext);
 
+clang::CXXRecordDecl *DeclareVkSampledTextureType(
+    clang::ASTContext &context, clang::DeclContext *declContext,
+    llvm::StringRef hlslTypeName, clang::QualType defaultParamType);
+
 clang::CXXRecordDecl *DeclareInlineSpirvType(clang::ASTContext &context,
                                              clang::DeclContext *declContext,
                                              llvm::StringRef typeName,

tools/clang/include/clang/SPIRV/AstTypeProbe.h

@@ -257,6 +257,9 @@ bool isTexture(QualType);
 /// Texture2DMSArray type.
 bool isTextureMS(QualType);
 
+/// \brief Returns true if the given type is an HLSL SampledTexture type.
+bool isSampledTexture(QualType);
+
 /// \brief Returns true if the given type is an HLSL RWTexture type.
 bool isRWTexture(QualType);
 

tools/clang/include/clang/SPIRV/SpirvBuilder.h

@@ -287,6 +287,10 @@ class SpirvBuilder {
   /// If compareVal is given a non-zero value, *Dref* variants of OpImageSample*
   /// will be generated.
   ///
+  /// If sampler is set, it defines the sampler along *image* to create the
+  /// combined image sampler. Otherwise, the *image* parameter must point to a
+  /// sampled image.
+  ///
   /// If lod or grad is given a non-zero value, *ExplicitLod variants of
   /// OpImageSample* will be generated; otherwise, *ImplicitLod variant will
   /// be generated.

tools/clang/lib/AST/ASTContextHLSL.cpp

@@ -1372,6 +1372,26 @@ CXXRecordDecl *hlsl::DeclareNodeOrRecordType(
 }
 
 #ifdef ENABLE_SPIRV_CODEGEN
+CXXRecordDecl *hlsl::DeclareVkSampledTextureType(ASTContext &context,
+                                                 DeclContext *declContext,
+                                                 llvm::StringRef hlslTypeName,
+                                                 QualType defaultParamType) {
+  // TODO(https://github.com/microsoft/DirectXShaderCompiler/issues/7979): Later
+  // generalize these to all SampledTexture types.
+  BuiltinTypeDeclBuilder Builder(declContext, hlslTypeName,
+                                 TagDecl::TagKind::TTK_Struct);
+
+  TemplateTypeParmDecl *TyParamDecl =
+      Builder.addTypeTemplateParam("SampledTextureType", defaultParamType);
+
+  Builder.startDefinition();
+
+  QualType paramType = QualType(TyParamDecl->getTypeForDecl(), 0);
+  CXXRecordDecl *recordDecl = Builder.getRecordDecl();
+
+  return recordDecl;
+}
+
 CXXRecordDecl *hlsl::DeclareVkBufferPointerType(ASTContext &context,
                                                 DeclContext *declContext) {
   BuiltinTypeDeclBuilder Builder(declContext, "BufferPointer",

tools/clang/lib/SPIRV/AstTypeProbe.cpp

@@ -926,6 +926,17 @@ bool isTexture(QualType type) {
   return false;
 }
 
+bool isSampledTexture(QualType type) {
+  if (const auto *rt = type->getAs<RecordType>()) {
+    const auto name = rt->getDecl()->getName();
+    // TODO(https://github.com/microsoft/DirectXShaderCompiler/issues/7979): Add
+    // other sampled texture types as needed.
+    if (name == "SampledTexture2D")
+      return true;
+  }
+  return false;
+}
+
 bool isTextureMS(QualType type) {
   if (const auto *rt = type->getAs<RecordType>()) {
     const auto name = rt->getDecl()->getName();

tools/clang/lib/SPIRV/LowerTypeVisitor.cpp

@@ -849,6 +849,23 @@ const SpirvType *LowerTypeVisitor::lowerVkTypeInVkNamespace(
     assert(visitedTypeStack.size() == visitedTypeStackSize);
     return pointerType;
   }
+  if (name == "SampledTexture2D") {
+    const auto sampledType = hlsl::GetHLSLResourceResultType(type);
+    auto loweredType = lowerType(getElementType(astContext, sampledType), rule,
+                                 /*isRowMajor*/ llvm::None, srcLoc);
+
+    // Bool does not have a defined size in SPIR-V, so it cannot be
+    // used in the external interface.
+    if (loweredType == spvContext.getBoolType()) {
+      loweredType = spvContext.getUIntType(32);
+    }
+
+    const auto *imageType = spvContext.getImageType(
+        loweredType, spv::Dim::Dim2D, ImageType::WithDepth::No,
+        false /* array */, false /* ms */, ImageType::WithSampler::Yes,
+        spv::ImageFormat::Unknown);
+    return spvContext.getSampledImageType(imageType);
+  }
   emitError("unknown type %0 in vk namespace", srcLoc) << type;
   return nullptr;
 }
@@ -892,7 +909,8 @@ LowerTypeVisitor::lowerResourceType(QualType type, SpirvLayoutRule rule,
       auto loweredType =
           lowerType(getElementType(astContext, sampledType), rule,
                     /*isRowMajor*/ llvm::None, srcLoc);
-      // Treat bool textures as uint for compatibility with OpTypeImage.
+      // Bool does not have a defined size in SPIR-V, so it cannot be
+      // used in the external interface.
       if (loweredType == spvContext.getBoolType()) {
         loweredType = spvContext.getUIntType(32);
       }

tools/clang/lib/SPIRV/SpirvBuilder.cpp

@@ -620,8 +620,15 @@ SpirvInstruction *SpirvBuilder::createImageSample(
   assert(lod == nullptr || minLod == nullptr);
 
   // An OpSampledImage is required to do the image sampling.
-  auto *sampledImage =
-      createSampledImage(imageType, image, sampler, loc, range);
+  // Skip creating OpSampledImage if the imageType is a sampled texture.
+  SpirvInstruction *sampledImage;
+  if (isSampledTexture(imageType)) {
+    assert(!sampler &&
+           "sampler must be null when sampling from a sampled texture");
+    sampledImage = image;
+  } else {
+    sampledImage = createSampledImage(imageType, image, sampler, loc, range);
+  }
 
   const auto mask = composeImageOperandsMask(
       bias, lod, grad, constOffset, varOffset, constOffsets, sample, minLod);

tools/clang/lib/SPIRV/SpirvEmitter.cpp

@@ -4474,14 +4474,27 @@ SpirvEmitter::processTextureLevelOfDetail(const CXXMemberCallExpr *expr,
   // TextureCube(Array).CalculateLevelOfDetail(SamplerState S, float3 xyz);
   // Texture3D.CalculateLevelOfDetail(SamplerState S, float3 xyz);
   // Return type is always a single float (LOD).
-  assert(expr->getNumArgs() == 2u);
-  const auto *object = expr->getImplicitObjectArgument();
-  auto *objectInfo = loadIfGLValue(object);
-  auto *samplerState = doExpr(expr->getArg(0));
-  auto *coordinate = doExpr(expr->getArg(1));
+  //
+  // Their SampledTexture variants have the same signature without the
+  // sampler_state parameter.
+  const auto *imageExpr = expr->getImplicitObjectArgument();
+  const QualType imageType = imageExpr->getType();
+  // numarg is 1 if isSampledTexture(imageType). otherwise 2.
+  assert(expr->getNumArgs() == (isSampledTexture(imageType) ? 1u : 2u));
+
+  auto *objectInfo = loadIfGLValue(imageExpr);
 
-  auto *sampledImage = spvBuilder.createSampledImage(
-      object->getType(), objectInfo, samplerState, expr->getExprLoc());
+  SpirvInstruction *samplerState, *coordinate, *sampledImage;
+  if (isSampledTexture(imageType)) {
+    samplerState = nullptr;
+    coordinate = doExpr(expr->getArg(0));
+    sampledImage = objectInfo;
+  } else {
+    samplerState = doExpr(expr->getArg(0));
+    coordinate = doExpr(expr->getArg(1));
+    sampledImage = spvBuilder.createSampledImage(
+        imageExpr->getType(), objectInfo, samplerState, expr->getExprLoc());
+  }
 
   // The result type of OpImageQueryLod must be a float2.
   const QualType queryResultType =
@@ -5817,6 +5830,9 @@ SpirvEmitter::processTextureSampleGather(const CXXMemberCallExpr *expr,
   //                           [, float Clamp]
   //                           [, out uint Status]);
   //
+  // Their SampledTexture variants have the same signature without the
+  // sampler_state parameter.
+  //
   // For TextureCube and TextureCubeArray:
   // DXGI_FORMAT Object.Sample(sampler_state S,
   //                           float Location
@@ -5835,35 +5851,49 @@ SpirvEmitter::processTextureSampleGather(const CXXMemberCallExpr *expr,
   //                                [, uint Status]);
   //
   // Other Texture types do not have a Gather method.
-
   const auto numArgs = expr->getNumArgs();
   const auto loc = expr->getExprLoc();
   const auto range = expr->getSourceRange();
   const bool hasStatusArg =
       expr->getArg(numArgs - 1)->getType()->isUnsignedIntegerType();
 
+  const auto *imageExpr = expr->getImplicitObjectArgument();
+  const QualType imageType = imageExpr->getType();
+  const bool isImageSampledTexture = isSampledTexture(imageType);
+
+  int samplerIndex;
+  uint32_t coordIndex;
+  if (isImageSampledTexture) {
+    samplerIndex = -1; // non-existant
+    coordIndex = 0;
+  } else {
+    samplerIndex = 0;
+    coordIndex = 1;
+  }
+
   SpirvInstruction *clamp = nullptr;
-  if (numArgs > 2 && expr->getArg(2)->getType()->isFloatingType())
-    clamp = doExpr(expr->getArg(2));
-  else if (numArgs > 3 && expr->getArg(3)->getType()->isFloatingType())
-    clamp = doExpr(expr->getArg(3));
+  if (numArgs > coordIndex + 1 &&
+      expr->getArg(coordIndex + 1)->getType()->isFloatingType())
+    clamp = doExpr(expr->getArg(coordIndex + 1));
+  else if (numArgs > coordIndex + 2 &&
+           expr->getArg(coordIndex + 2)->getType()->isFloatingType())
+    clamp = doExpr(expr->getArg(coordIndex + 2));
   const bool hasClampArg = (clamp != 0);
   const auto status =
       hasStatusArg ? doExpr(expr->getArg(numArgs - 1)) : nullptr;
 
-  // Subtract 1 for status (if it exists), subtract 1 for clamp (if it exists),
-  // and subtract 2 for sampler_state and location.
-  const bool hasOffsetArg = numArgs - hasStatusArg - hasClampArg - 2 > 0;
-
-  const auto *imageExpr = expr->getImplicitObjectArgument();
-  const QualType imageType = imageExpr->getType();
   auto *image = loadIfGLValue(imageExpr);
-  auto *sampler = doExpr(expr->getArg(0));
-  auto *coordinate = doExpr(expr->getArg(1));
+  SpirvInstruction *sampler =
+      samplerIndex >= 0 ? doExpr(expr->getArg(samplerIndex)) : nullptr;
+  auto *coordinate = doExpr(expr->getArg(coordIndex));
   // .Sample()/.Gather() may have a third optional paramter for offset.
   SpirvInstruction *constOffset = nullptr, *varOffset = nullptr;
+  // Subtract 1 for status (if it exists), subtract 1 for clamp (if it exists),
+  // and subtract offsetIndex for sampler_state (if exists) location.
+  const bool hasOffsetArg =
+      numArgs - hasStatusArg - hasClampArg - coordIndex > 1;
   if (hasOffsetArg)
-    handleOffsetInMethodCall(expr, 2, &constOffset, &varOffset);
+    handleOffsetInMethodCall(expr, coordIndex + 1, &constOffset, &varOffset);
 
   const auto retType = expr->getDirectCallee()->getReturnType();
   if (isSample) {

tools/clang/lib/Sema/SemaHLSL.cpp

@@ -199,6 +199,7 @@ enum ArBasicKind {
   AR_OBJECT_VK_SPV_INTRINSIC_TYPE,
   AR_OBJECT_VK_SPV_INTRINSIC_RESULT_ID,
   AR_OBJECT_VK_BUFFER_POINTER,
+  AR_OBJECT_VK_SAMPLED_TEXTURE2D,
 #endif // ENABLE_SPIRV_CODEGEN
   // SPIRV change ends
 
@@ -559,6 +560,7 @@ const UINT g_uBasicKindProps[] = {
     BPROP_OBJECT, // AR_OBJECT_VK_SPV_INTRINSIC_TYPE use recordType
     BPROP_OBJECT, // AR_OBJECT_VK_SPV_INTRINSIC_RESULT_ID use recordType
     BPROP_OBJECT, // AR_OBJECT_VK_BUFFER_POINTER use recordType
+    BPROP_OBJECT | BPROP_RBUFFER, // AR_OBJECT_VK_SAMPLED_TEXTURE2D
 #endif            // ENABLE_SPIRV_CODEGEN
     // SPIRV change ends
 
@@ -1267,6 +1269,8 @@ static const ArBasicKind g_LinAlgMatrixCT[] = {AR_OBJECT_LINALG_MATRIX,
 #ifdef ENABLE_SPIRV_CODEGEN
 static const ArBasicKind g_VKBufferPointerCT[] = {AR_OBJECT_VK_BUFFER_POINTER,
                                                   AR_BASIC_UNKNOWN};
+static const ArBasicKind g_VKSampledTexture2DCT[] = {
+    AR_OBJECT_VK_SAMPLED_TEXTURE2D, AR_BASIC_UNKNOWN};
 #endif
 
 // Basic kinds, indexed by a LEGAL_INTRINSIC_COMPTYPES value.
@@ -1329,7 +1333,8 @@ const ArBasicKind *g_LegalIntrinsicCompTypes[] = {
     g_LinAlgCT,                   // LICOMPTYPE_LINALG
     g_BuiltInTrianglePositionsCT, // LICOMPTYPE_BUILTIN_TRIANGLE_POSITIONS
 #ifdef ENABLE_SPIRV_CODEGEN
-    g_VKBufferPointerCT, // LICOMPTYPE_VK_BUFFER_POINTER
+    g_VKBufferPointerCT,    // LICOMPTYPE_VK_BUFFER_POINTER
+    g_VKSampledTexture2DCT, // LICOMPTYPE_VK_SAMPLED_TEXTURE2D
 #endif
 };
 static_assert(
@@ -1389,7 +1394,7 @@ static const ArBasicKind g_ArBasicKindsAsTypes[] = {
     AR_OBJECT_VK_SPIRV_TYPE, AR_OBJECT_VK_SPIRV_OPAQUE_TYPE,
     AR_OBJECT_VK_INTEGRAL_CONSTANT, AR_OBJECT_VK_LITERAL,
     AR_OBJECT_VK_SPV_INTRINSIC_TYPE, AR_OBJECT_VK_SPV_INTRINSIC_RESULT_ID,
-    AR_OBJECT_VK_BUFFER_POINTER,
+    AR_OBJECT_VK_BUFFER_POINTER, AR_OBJECT_VK_SAMPLED_TEXTURE2D,
 #endif // ENABLE_SPIRV_CODEGEN
     // SPIRV change ends
 
@@ -1501,6 +1506,7 @@ static const uint8_t g_ArBasicKindsTemplateCount[] = {
     1, // AR_OBJECT_VK_SPV_INTRINSIC_TYPE
     1, // AR_OBJECT_VK_SPV_INTRINSIC_RESULT_ID
     2, // AR_OBJECT_VK_BUFFER_POINTER
+    1, // AR_OBJECT_VK_SAMPLED_TEXTURE2D
 #endif // ENABLE_SPIRV_CODEGEN
     // SPIRV change ends
 
@@ -1654,6 +1660,7 @@ static const SubscriptOperatorRecord g_ArBasicKindsSubscripts[] = {
     {0, MipsFalse, SampleFalse}, // AR_OBJECT_VK_SPV_INTRINSIC_TYPE
     {0, MipsFalse, SampleFalse}, // AR_OBJECT_VK_SPV_INTRINSIC_RESULT_ID
     {0, MipsFalse, SampleFalse}, // AR_OBJECT_VK_BUFFER_POINTER
+    {0, MipsFalse, SampleFalse}, // AR_OBJECT_VK_SAMPLED_TEXTURE2D
 #endif                           // ENABLE_SPIRV_CODEGEN
     // SPIRV change ends
 
@@ -1823,6 +1830,7 @@ static const char *g_ArBasicTypeNames[] = {
     "ext_type",
     "ext_result_id",
     "BufferPointer",
+    "SampledTexture2D",
 #endif // ENABLE_SPIRV_CODEGEN
     // SPIRV change ends
 
@@ -2475,6 +2483,12 @@ static void GetIntrinsicMethods(ArBasicKind kind,
     *intrinsics = g_RayQueryMethods;
     *intrinsicCount = _countof(g_RayQueryMethods);
     break;
+#ifdef ENABLE_SPIRV_CODEGEN
+  case AR_OBJECT_VK_SAMPLED_TEXTURE2D:
+    *intrinsics = g_VkSampledTexture2DMethods;
+    *intrinsicCount = _countof(g_VkSampledTexture2DMethods);
+    break;
+#endif
   case AR_OBJECT_HIT_OBJECT:
     *intrinsics = g_DxHitObjectMethods;
     *intrinsicCount = _countof(g_DxHitObjectMethods);
@@ -3073,6 +3087,7 @@ class HLSLExternalSource : public ExternalSemaSource {
   ClassTemplateDecl *m_vkIntegralConstantTemplateDecl;
   ClassTemplateDecl *m_vkLiteralTemplateDecl;
   ClassTemplateDecl *m_vkBufferPointerTemplateDecl;
+  ClassTemplateDecl *m_vkSampledTextureTemplateDecl;
 
   // Declarations for Work Graph Output Record types
   ClassTemplateDecl *m_GroupNodeOutputRecordsTemplateDecl;
@@ -4078,6 +4093,15 @@ class HLSLExternalSource : public ExternalSemaSource {
         recordDecl = DeclareVkBufferPointerType(*m_context, m_vkNSDecl);
         recordDecl->setImplicit(true);
         m_vkBufferPointerTemplateDecl = recordDecl->getDescribedClassTemplate();
+      } else if (kind == AR_OBJECT_VK_SAMPLED_TEXTURE2D) {
+        if (!m_vkNSDecl)
+          continue;
+        QualType float4Type =
+            LookupVectorType(HLSLScalarType::HLSLScalarType_float, 4);
+        recordDecl = DeclareVkSampledTextureType(
+            *m_context, m_vkNSDecl, "SampledTexture2D", float4Type);
+        m_vkSampledTextureTemplateDecl =
+            recordDecl->getDescribedClassTemplate();
       }
 #endif
       else if (templateArgCount == 0) {
@@ -4191,7 +4215,8 @@ class HLSLExternalSource : public ExternalSemaSource {
       : m_matrixTemplateDecl(nullptr), m_vectorTemplateDecl(nullptr),
         m_vkIntegralConstantTemplateDecl(nullptr),
         m_vkLiteralTemplateDecl(nullptr),
-        m_vkBufferPointerTemplateDecl(nullptr), m_hlslNSDecl(nullptr),
+        m_vkBufferPointerTemplateDecl(nullptr),
+        m_vkSampledTextureTemplateDecl(nullptr), m_hlslNSDecl(nullptr),
         m_vkNSDecl(nullptr), m_dxNSDecl(nullptr), m_context(nullptr),
         m_sema(nullptr), m_hlslStringTypedef(nullptr) {
     memset(m_matrixTypes, 0, sizeof(m_matrixTypes));