[SPIRV] Allow sampled type to be half for universal (microsoft#7252)

We have a check that the sample type for an image cannot be a 16-bit
float. This is true for Vulkan, but not true for general spir-v.

We modify this check to only apply when the target env is vulkan. Wew
also move the check to spirvemitter where the error handling is better.
In its current location, the compiler continue to run with an unexpected
nullptr.

Fixes microsoft#6987
Fixes microsoft#6989

---------

Co-authored-by: Cassandra Beckley <[email protected]>

Author: s-perron

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

@@ -132,6 +132,9 @@ class FeatureManager {
   /// Returns false otherwise.
   bool isTargetEnvVulkan1p3OrAbove();
 
+  /// Return true if the target environment is a Vulkan environment.
+  bool isTargetEnvVulkan();
+
   /// Returns the spv_target_env matching the input string if possible.
   /// This functions matches the spv_target_env with the command-line version
   /// of the name ('vulkan1.1', not 'Vulkan 1.1').

tools/clang/lib/SPIRV/FeatureManager.cpp

@@ -405,5 +405,23 @@ bool FeatureManager::isTargetEnvVulkan1p3OrAbove() {
   return targetEnv >= SPV_ENV_VULKAN_1_3;
 }
 
+bool FeatureManager::isTargetEnvVulkan() {
+  // This assert ensure that this list will be updated, if necessary, when
+  // a new target environment is added.
+  static_assert(SPV_ENV_VULKAN_1_4 + 1 == SPV_ENV_MAX);
+
+  switch (targetEnv) {
+  case SPV_ENV_VULKAN_1_0:
+  case SPV_ENV_VULKAN_1_1:
+  case SPV_ENV_VULKAN_1_2:
+  case SPV_ENV_VULKAN_1_1_SPIRV_1_4:
+  case SPV_ENV_VULKAN_1_3:
+  case SPV_ENV_VULKAN_1_4:
+    return true;
+  default:
+    return false;
+  }
+}
+
 } // end namespace spirv
 } // end namespace clang

tools/clang/lib/SPIRV/LowerTypeVisitor.cpp

@@ -834,26 +834,6 @@ LowerTypeVisitor::lowerResourceType(QualType type, SpirvLayoutRule rule,
 
   // TODO: avoid string comparison once hlsl::IsHLSLResouceType() does that.
 
-  // Vulkan does not yet support true 16-bit float texture objexts.
-  if (name == "Buffer" || name == "RWBuffer" || name == "Texture1D" ||
-      name == "Texture2D" || name == "Texture3D" || name == "TextureCube" ||
-      name == "Texture1DArray" || name == "Texture2DArray" ||
-      name == "Texture2DMS" || name == "Texture2DMSArray" ||
-      name == "TextureCubeArray" || name == "RWTexture1D" ||
-      name == "RWTexture2D" || name == "RWTexture3D" ||
-      name == "RWTexture1DArray" || name == "RWTexture2DArray") {
-    const auto sampledType = hlsl::GetHLSLResourceResultType(type);
-    const auto loweredType =
-        lowerType(getElementType(astContext, sampledType), rule,
-                  /*isRowMajor*/ llvm::None, srcLoc);
-    if (const auto *floatType = dyn_cast<FloatType>(loweredType)) {
-      if (floatType->getBitwidth() == 16) {
-        emitError("16-bit texture types not yet supported with -spirv", srcLoc);
-        return nullptr;
-      }
-    }
-  }
-
   { // Texture types
     spv::Dim dim = {};
     bool isArray = {};

tools/clang/lib/SPIRV/SpirvEmitter.cpp

@@ -1880,6 +1880,19 @@ void SpirvEmitter::doVarDecl(const VarDecl *decl) {
     }
   }
 
+  if (featureManager.isTargetEnvVulkan() &&
+      (isTexture(decl->getType()) || isRWTexture(decl->getType()) ||
+       isBuffer(decl->getType()) || isRWBuffer(decl->getType()))) {
+    const auto sampledType = hlsl::GetHLSLResourceResultType(decl->getType());
+    if (isFloatOrVecMatOfFloatType(sampledType) &&
+        isOrContains16BitType(sampledType, spirvOptions.enable16BitTypes)) {
+      emitError("The sampled type for textures cannot be a floating point type "
+                "smaller than 32-bits when targeting a Vulkan environment.",
+                loc);
+      return;
+    }
+  }
+
   if (decl->hasAttr<VKConstantIdAttr>()) {
     // This is a VarDecl for specialization constant.
     createSpecConstant(decl);

tools/clang/test/CodeGenSPIRV/type.buffer.half.hlsl

@@ -1,6 +1,14 @@
-// RUN: not %dxc -T ps_6_6 -E main -fcgl  %s -spirv -enable-16bit-types  2>&1 | FileCheck %s
+// RUN: not %dxc -T ps_6_6 -E main -fcgl  %s -spirv -enable-16bit-types  2>&1 | FileCheck %s --check-prefix=VK
+// RUN: %dxc -T ps_6_6 -E main -fcgl  %s -spirv -fspv-target-env=universal1.5 -enable-16bit-types  2>&1 | FileCheck %s --check-prefix=UNIVERSAL
 
-// CHECK: error: 16-bit texture types not yet supported with -spirv
+// When targeting Vulkan, A 16-bit floating pointer buffer is not valid.
+// VK: error: The sampled type for textures cannot be a floating point type smaller than 32-bits when targeting a Vulkan environment.
+
+// When not targeting Vulkan, we should generate the 16-bit floating pointer buffer.
+// UNIVERSAL: %half = OpTypeFloat 16
+// UNIVERSAL: %type_buffer_image = OpTypeImage %half Buffer 2 0 0 1 Unknown
+// UNIVERSAL: %_ptr_UniformConstant_type_buffer_image = OpTypePointer UniformConstant %type_buffer_image
+// UNIVERSAL: %MyBuffer = OpVariable %_ptr_UniformConstant_type_buffer_image UniformConstant
 Buffer<half> MyBuffer;
 
 void main(): SV_Target { }

tools/clang/test/CodeGenSPIRV/type.buffer.half4.hlsl

@@ -0,0 +1,14 @@
+// RUN: not %dxc -T ps_6_6 -E main -fcgl  %s -spirv -enable-16bit-types  2>&1 | FileCheck %s --check-prefix=VK
+// RUN: %dxc -T ps_6_6 -E main -fcgl  %s -spirv -fspv-target-env=universal1.5 -enable-16bit-types  2>&1 | FileCheck %s --check-prefix=UNIVERSAL
+
+// When targeting Vulkan, A 16-bit floating pointer buffer is not valid.
+// VK: error: The sampled type for textures cannot be a floating point type smaller than 32-bits when targeting a Vulkan environment.
+
+// When not targeting Vulkan, we should generate the 16-bit floating pointer buffer.
+// UNIVERSAL: %half = OpTypeFloat 16
+// UNIVERSAL: %type_buffer_image = OpTypeImage %half Buffer 2 0 0 1 Unknown
+// UNIVERSAL: %_ptr_UniformConstant_type_buffer_image = OpTypePointer UniformConstant %type_buffer_image
+// UNIVERSAL: %MyBuffer = OpVariable %_ptr_UniformConstant_type_buffer_image UniformConstant
+Buffer<half4> MyBuffer;
+
+void main(): SV_Target { }