[spirv] Add VK_AMD_shader_early_and_late_fragment_tests support (#4504)

Author: Junda Liu

docs/SPIR-V.rst

@@ -288,13 +288,14 @@ Supported extensions
 
 * SPV_KHR_16bit_storage
 * SPV_KHR_device_group
+* SPV_KHR_fragment_shading_rate
 * SPV_KHR_multivew
 * SPV_KHR_post_depth_coverage
 * SPV_KHR_shader_draw_parameters
 * SPV_EXT_descriptor_indexing
 * SPV_EXT_fragment_fully_covered
-* SPV_KHR_fragment_shading_rate
 * SPV_EXT_shader_stencil_support
+* SPV_AMD_shader_early_and_late_fragment_tests
 * SPV_AMD_shader_explicit_vertex_parameter
 * SPV_GOOGLE_hlsl_functionality1
 * SPV_GOOGLE_user_type
@@ -340,6 +341,40 @@ The namespace ``vk`` will be used for all Vulkan attributes:
   sampler (or sampled image) type with the same descriptor set and binding numbers (see
   `wiki page <https://github.com/microsoft/DirectXShaderCompiler/wiki/Vulkan-combined-image-sampler-type>`_
   for more detail).
+- ``early_and_late_tests``: Marks an entry point as enabling early and late depth
+  tests. If depth is written via ``SV_Depth``, ``depth_unchanged`` must also be specified
+  (``SV_DepthLess`` and ``SV_DepthGreater`` can be written freely). If a stencil reference
+  value is written via ``SV_StencilRef``, one of ``stencil_ref_unchanged_front``,
+  ``stencil_ref_greater_equal_front``, or ``stencil_ref_less_equal_front`` and
+  one of ``stencil_ref_unchanged_back``, ``stencil_ref_greater_equal_back``, or
+  ``stencil_ref_less_equal_back`` must be specified.
+- ``depth_unchanged``: Specifies that any depth written to ``SV_Depth`` will not
+  invalidate the result of early depth tests. Sets the ``DepthUnchanged`` execution
+  mode in SPIR-V. Only valid on pixel shader entry points.
+- ``stencil_ref_unchanged_front``: Specifies that any stencil ref written to
+  ``SV_StencilRef`` will not invalidate the result of early stencil tests when
+  the fragment is front facing. Sets the ``StencilRefUnchangedFrontAMD`` execution
+  mode in SPIR-V. Only valid on pixel shader entry points.
+- ``stencil_ref_greater_equal_front``: Specifies that any stencil ref written to
+  ``SV_StencilRef`` will be greater than or equal to the stencil reference value
+  set by the API when the fragment is front facing. Sets the ``StencilRefGreaterFrontAMD``
+  execution mode in SPIR-V. Only valid on pixel shader entry points.
+- ``stencil_ref_less_equal_front``: Specifies that any stencil ref written to
+  ``SV_StencilRef`` will be less than or equal to the stencil reference value
+  set by the API when the fragment is front facing. Sets the ``StencilRefLessFrontAMD``
+  execution mode in SPIR-V. Only valid on pixel shader entry points.
+- ``stencil_ref_unchanged_back``: Specifies that any stencil ref written to
+  ``SV_StencilRef`` will not invalidate the result of early stencil tests when
+  the fragment is back facing. Sets the ``StencilRefUnchangedBackAMD`` execution
+  mode in SPIR-V. Only valid on pixel shader entry points.
+- ``stencil_ref_greater_equal_back``: Specifies that any stencil ref written to
+  ``SV_StencilRef`` will be greater than or equal to the stencil reference value
+  set by the API when the fragment is back facing. Sets the ``StencilRefGreaterBackAMD``
+  execution mode in SPIR-V. Only valid on pixel shader entry points.
+- ``stencil_ref_less_equal_back``: Specifies that any stencil ref written to
+  ``SV_StencilRef`` will be less than or equal to the stencil reference value
+  set by the API when the fragment is back facing. Sets the ``StencilRefLessBackAMD``
+  execution mode in SPIR-V. Only valid on pixel shader entry points.
 
 Only ``vk::`` attributes in the above list are supported. Other attributes will
 result in warnings and be ignored by the compiler. All C++11 attributes will

tools/clang/include/clang/Basic/Attr.td

@@ -1201,6 +1201,62 @@ def VKShaderRecordEXT : InheritableAttr {
   let LangOpts = [SPIRV];
   let Documentation = [Undocumented];
 }
+
+def VKEarlyAndLateTests : InheritableAttr {
+  let Spellings = [CXX11<"vk", "early_and_late_tests">];
+  let Subjects = SubjectList<[Function], ErrorDiag>;
+  let LangOpts = [SPIRV];
+  let Documentation = [Undocumented];
+}
+
+def VKDepthUnchanged : InheritableAttr {
+  let Spellings = [CXX11<"vk", "depth_unchanged">];
+  let Subjects = SubjectList<[Function], ErrorDiag>;
+  let LangOpts = [SPIRV];
+  let Documentation = [Undocumented];
+}
+
+def VKStencilRefUnchangedFront : InheritableAttr {
+  let Spellings = [CXX11<"vk", "stencil_ref_unchanged_front">];
+  let Subjects = SubjectList<[Function], ErrorDiag>;
+  let LangOpts = [SPIRV];
+  let Documentation = [Undocumented];
+}
+
+def VKStencilRefGreaterEqualFront : InheritableAttr {
+  let Spellings = [CXX11<"vk", "stencil_ref_greater_equal_front">];
+  let Subjects = SubjectList<[Function], ErrorDiag>;
+  let LangOpts = [SPIRV];
+  let Documentation = [Undocumented];
+}
+
+def VKStencilRefLessEqualFront : InheritableAttr {
+  let Spellings = [CXX11<"vk", "stencil_ref_less_equal_front">];
+  let Subjects = SubjectList<[Function], ErrorDiag>;
+  let LangOpts = [SPIRV];
+  let Documentation = [Undocumented];
+}
+
+def VKStencilRefUnchangedBack : InheritableAttr {
+  let Spellings = [CXX11<"vk", "stencil_ref_unchanged_back">];
+  let Subjects = SubjectList<[Function], ErrorDiag>;
+  let LangOpts = [SPIRV];
+  let Documentation = [Undocumented];
+}
+
+def VKStencilRefGreaterEqualBack : InheritableAttr {
+  let Spellings = [CXX11<"vk", "stencil_ref_greater_equal_back">];
+  let Subjects = SubjectList<[Function], ErrorDiag>;
+  let LangOpts = [SPIRV];
+  let Documentation = [Undocumented];
+}
+
+def VKStencilRefLessEqualBack : InheritableAttr {
+  let Spellings = [CXX11<"vk", "stencil_ref_less_equal_back">];
+  let Subjects = SubjectList<[Function], ErrorDiag>;
+  let LangOpts = [SPIRV];
+  let Documentation = [Undocumented];
+}
 // SPIRV Change Ends
 
 def C11NoReturn : InheritableAttr {

tools/clang/include/clang/SPIRV/FeatureManager.h

@@ -45,6 +45,7 @@ enum class Extension {
   EXT_shader_stencil_export,
   EXT_shader_viewport_index_layer,
   AMD_gpu_shader_half_float,
+  AMD_shader_early_and_late_fragment_tests,
   AMD_shader_explicit_vertex_parameter,
   GOOGLE_hlsl_functionality1,
   GOOGLE_user_type,

tools/clang/lib/SPIRV/CapabilityVisitor.cpp

@@ -602,11 +602,71 @@ bool CapabilityVisitor::visit(SpirvEntryPoint *entryPoint) {
 }
 
 bool CapabilityVisitor::visit(SpirvExecutionMode *execMode) {
-  if (execMode->getExecutionMode() == spv::ExecutionMode::PostDepthCoverage) {
+  spv::ExecutionMode executionMode = execMode->getExecutionMode();
+  SourceLocation execModeSourceLocation = execMode->getSourceLocation();
+  SourceLocation entryPointSourceLocation =
+      execMode->getEntryPoint()->getSourceLocation();
+  switch (executionMode) {
+  case spv::ExecutionMode::PostDepthCoverage:
     addCapability(spv::Capability::SampleMaskPostDepthCoverage,
-                  execMode->getEntryPoint()->getSourceLocation());
+                  entryPointSourceLocation);
     addExtension(Extension::KHR_post_depth_coverage,
-                 "[[vk::post_depth_coverage]]", execMode->getSourceLocation());
+                 "[[vk::post_depth_coverage]]", execModeSourceLocation);
+    break;
+  case spv::ExecutionMode::EarlyAndLateFragmentTestsAMD:
+    addExtension(Extension::AMD_shader_early_and_late_fragment_tests,
+                 "[[vk::early_and_late_tests]]", execModeSourceLocation);
+    break;
+  case spv::ExecutionMode::StencilRefUnchangedFrontAMD:
+    addCapability(spv::Capability::StencilExportEXT, entryPointSourceLocation);
+    addExtension(Extension::AMD_shader_early_and_late_fragment_tests,
+                 "[[vk::stencil_ref_unchanged_front]]", execModeSourceLocation);
+    addExtension(Extension::EXT_shader_stencil_export,
+                 "[[vk::stencil_ref_unchanged_front]]", execModeSourceLocation);
+    break;
+  case spv::ExecutionMode::StencilRefGreaterFrontAMD:
+    addCapability(spv::Capability::StencilExportEXT, entryPointSourceLocation);
+    addExtension(Extension::AMD_shader_early_and_late_fragment_tests,
+                 "[[vk::stencil_ref_greater_equal_front]]",
+                 execModeSourceLocation);
+    addExtension(Extension::EXT_shader_stencil_export,
+                 "[[vk::stencil_ref_greater_equal_front]]",
+                 execModeSourceLocation);
+    break;
+  case spv::ExecutionMode::StencilRefLessFrontAMD:
+    addCapability(spv::Capability::StencilExportEXT, entryPointSourceLocation);
+    addExtension(Extension::AMD_shader_early_and_late_fragment_tests,
+                 "[[vk::stencil_ref_less_equal_front]]",
+                 execModeSourceLocation);
+    addExtension(Extension::EXT_shader_stencil_export,
+                 "[[vk::stencil_ref_less_equal_front]]",
+                 execModeSourceLocation);
+    break;
+  case spv::ExecutionMode::StencilRefUnchangedBackAMD:
+    addCapability(spv::Capability::StencilExportEXT, entryPointSourceLocation);
+    addExtension(Extension::AMD_shader_early_and_late_fragment_tests,
+                 "[[vk::stencil_ref_unchanged_back]]", execModeSourceLocation);
+    addExtension(Extension::EXT_shader_stencil_export,
+                 "[[vk::stencil_ref_unchanged_back]]", execModeSourceLocation);
+    break;
+  case spv::ExecutionMode::StencilRefGreaterBackAMD:
+    addCapability(spv::Capability::StencilExportEXT, entryPointSourceLocation);
+    addExtension(Extension::AMD_shader_early_and_late_fragment_tests,
+                 "[[vk::stencil_ref_greater_equal_back]]",
+                 execModeSourceLocation);
+    addExtension(Extension::EXT_shader_stencil_export,
+                 "[[vk::stencil_ref_greater_equal_back]]",
+                 execModeSourceLocation);
+    break;
+  case spv::ExecutionMode::StencilRefLessBackAMD:
+    addCapability(spv::Capability::StencilExportEXT, entryPointSourceLocation);
+    addExtension(Extension::AMD_shader_early_and_late_fragment_tests,
+                 "[[vk::stencil_ref_less_equal_back]]", execModeSourceLocation);
+    addExtension(Extension::EXT_shader_stencil_export,
+                 "[[vk::stencil_ref_less_equal_back]]", execModeSourceLocation);
+    break;
+  default:
+    break;
   }
   return true;
 }

tools/clang/lib/SPIRV/FeatureManager.cpp

@@ -148,6 +148,8 @@ Extension FeatureManager::getExtensionSymbol(llvm::StringRef name) {
             Extension::EXT_shader_viewport_index_layer)
       .Case("SPV_AMD_gpu_shader_half_float",
             Extension::AMD_gpu_shader_half_float)
+      .Case("SPV_AMD_shader_early_and_late_fragment_tests",
+            Extension::AMD_shader_early_and_late_fragment_tests)
       .Case("SPV_AMD_shader_explicit_vertex_parameter",
             Extension::AMD_shader_explicit_vertex_parameter)
       .Case("SPV_GOOGLE_hlsl_functionality1",
@@ -201,6 +203,8 @@ const char *FeatureManager::getExtensionName(Extension symbol) {
     return "SPV_EXT_shader_viewport_index_layer";
   case Extension::AMD_gpu_shader_half_float:
     return "SPV_AMD_gpu_shader_half_float";
+  case Extension::AMD_shader_early_and_late_fragment_tests:
+    return "SPV_AMD_shader_early_and_late_fragment_tests";
   case Extension::AMD_shader_explicit_vertex_parameter:
     return "SPV_AMD_shader_explicit_vertex_parameter";
   case Extension::GOOGLE_hlsl_functionality1:

tools/clang/lib/SPIRV/SpirvEmitter.cpp

@@ -11472,6 +11472,70 @@ void SpirvEmitter::processPixelShaderAttributes(const FunctionDecl *decl) {
                                 spv::ExecutionMode::PostDepthCoverage, {},
                                 decl->getLocation());
   }
+  if (decl->getAttr<VKEarlyAndLateTestsAttr>()) {
+    spvBuilder.addExecutionMode(
+        entryFunction, spv::ExecutionMode::EarlyAndLateFragmentTestsAMD, {},
+        decl->getLocation());
+  }
+  if (decl->getAttr<VKDepthUnchangedAttr>()) {
+    spvBuilder.addExecutionMode(entryFunction,
+                                spv::ExecutionMode::DepthUnchanged, {},
+                                decl->getLocation());
+  }
+
+  // Shaders must not specify more than one of stencil_ref_unchanged_front,
+  // stencil_ref_greater_equal_front, and stencil_ref_less_equal_front.
+  // Shaders must not specify more than one of stencil_ref_unchanged_back,
+  // stencil_ref_greater_equal_back,and stencil_ref_less_equal_back.
+  uint32_t stencilFrontAttrCount = 0, stencilBackAttrCount = 0;
+  if (decl->getAttr<VKStencilRefUnchangedFrontAttr>()) {
+    ++stencilFrontAttrCount;
+    spvBuilder.addExecutionMode(entryFunction,
+                                spv::ExecutionMode::StencilRefUnchangedFrontAMD,
+                                {}, decl->getLocation());
+  }
+  if (decl->getAttr<VKStencilRefGreaterEqualFrontAttr>()) {
+    ++stencilFrontAttrCount;
+    spvBuilder.addExecutionMode(entryFunction,
+                                spv::ExecutionMode::StencilRefGreaterFrontAMD,
+                                {}, decl->getLocation());
+  }
+  if (decl->getAttr<VKStencilRefLessEqualFrontAttr>()) {
+    ++stencilFrontAttrCount;
+    spvBuilder.addExecutionMode(entryFunction,
+                                spv::ExecutionMode::StencilRefLessFrontAMD, {},
+                                decl->getLocation());
+  }
+  if (decl->getAttr<VKStencilRefUnchangedBackAttr>()) {
+    ++stencilBackAttrCount;
+    spvBuilder.addExecutionMode(entryFunction,
+                                spv::ExecutionMode::StencilRefUnchangedBackAMD,
+                                {}, decl->getLocation());
+  }
+  if (decl->getAttr<VKStencilRefGreaterEqualBackAttr>()) {
+    ++stencilBackAttrCount;
+    spvBuilder.addExecutionMode(entryFunction,
+                                spv::ExecutionMode::StencilRefGreaterBackAMD,
+                                {}, decl->getLocation());
+  }
+  if (decl->getAttr<VKStencilRefLessEqualBackAttr>()) {
+    ++stencilBackAttrCount;
+    spvBuilder.addExecutionMode(entryFunction,
+                                spv::ExecutionMode::StencilRefLessBackAMD, {},
+                                decl->getLocation());
+  }
+  if (stencilFrontAttrCount > 1) {
+    emitError("Shaders must not specify more than one of "
+              "stencil_ref_unchanged_front, stencil_ref_greater_equal_front, "
+              "and stencil_ref_less_equal_front.",
+              {});
+  }
+  if (stencilBackAttrCount > 1) {
+    emitError(
+        "Shaders must not specify more than one of stencil_ref_unchanged_back, "
+        "stencil_ref_greater_equal_back, and stencil_ref_less_equal_back.",
+        {});
+  }
 }
 
 void SpirvEmitter::processComputeShaderAttributes(const FunctionDecl *decl) {

tools/clang/lib/Sema/SemaHLSL.cpp

@@ -12449,6 +12449,36 @@ void hlsl::HandleDeclAttributeForHLSL(Sema &S, Decl *D, const AttributeList &A,
   case AttributeList::AT_VKPostDepthCoverage:
     declAttr = ::new (S.Context) VKPostDepthCoverageAttr(A.getRange(), S.Context, A.getAttributeSpellingListIndex());
     break;
+  case AttributeList::AT_VKEarlyAndLateTests:
+    declAttr = ::new (S.Context) VKEarlyAndLateTestsAttr(A.getRange(), S.Context, A.getAttributeSpellingListIndex());
+    break;
+  case AttributeList::AT_VKDepthUnchanged:
+    declAttr = ::new (S.Context) VKDepthUnchangedAttr(A.getRange(), S.Context, A.getAttributeSpellingListIndex());
+    break;
+  case AttributeList::AT_VKStencilRefUnchangedFront:
+    declAttr = ::new (S.Context) VKStencilRefUnchangedFrontAttr(
+        A.getRange(), S.Context, A.getAttributeSpellingListIndex());
+    break;
+  case AttributeList::AT_VKStencilRefGreaterEqualFront:
+    declAttr = ::new (S.Context) VKStencilRefGreaterEqualFrontAttr(
+        A.getRange(), S.Context, A.getAttributeSpellingListIndex());
+    break;
+  case AttributeList::AT_VKStencilRefLessEqualFront:
+    declAttr = ::new (S.Context) VKStencilRefLessEqualFrontAttr(
+        A.getRange(), S.Context, A.getAttributeSpellingListIndex());
+    break;
+  case AttributeList::AT_VKStencilRefUnchangedBack:
+    declAttr = ::new (S.Context) VKStencilRefUnchangedBackAttr(
+        A.getRange(), S.Context, A.getAttributeSpellingListIndex());
+    break;
+  case AttributeList::AT_VKStencilRefGreaterEqualBack:
+    declAttr = ::new (S.Context) VKStencilRefGreaterEqualBackAttr(
+        A.getRange(), S.Context, A.getAttributeSpellingListIndex());
+    break;
+  case AttributeList::AT_VKStencilRefLessEqualBack:
+    declAttr = ::new (S.Context) VKStencilRefLessEqualBackAttr(
+        A.getRange(), S.Context, A.getAttributeSpellingListIndex());
+    break;
   case AttributeList::AT_VKShaderRecordNV:
     declAttr = ::new (S.Context) VKShaderRecordNVAttr(A.getRange(), S.Context, A.getAttributeSpellingListIndex());
     break;

tools/clang/test/CodeGenSPIRV/vk.early-and-lates-tests.depth-unchanged.hlsl

@@ -0,0 +1,9 @@
+// RUN: %dxc -T ps_6_0 -E main
+
+// CHECK: OpExtension "SPV_AMD_shader_early_and_late_fragment_tests"
+// CHECK: OpExecutionMode %main EarlyAndLateFragmentTestsAMD
+// CHECK: OpExecutionMode %main DepthUnchanged
+
+[[vk::early_and_late_tests]]
+[[vk::depth_unchanged]]
+void main() {}

tools/clang/test/CodeGenSPIRV/vk.early-and-lates-tests.hlsl

@@ -0,0 +1,7 @@
+// RUN: %dxc -T ps_6_0 -E main
+
+// CHECK: OpExtension "SPV_AMD_shader_early_and_late_fragment_tests"
+// CHECK: OpExecutionMode %main EarlyAndLateFragmentTestsAMD
+
+[[vk::early_and_late_tests]]
+void main() {}

tools/clang/test/CodeGenSPIRV/vk.early-and-lates-tests.stencil-ref-error-back.hlsl

@@ -0,0 +1,8 @@
+// RUN: %dxc -T ps_6_0 -E main
+
+// CHECK: error: Shaders must not specify more than one of stencil_ref_unchanged_back, stencil_ref_greater_equal_back, and stencil_ref_less_equal_back.
+
+[[vk::early_and_late_tests]]
+[[vk::stencil_ref_less_equal_back]]
+[[vk::stencil_ref_greater_equal_back]]
+void main() {}