Fix layout checks with untyped pointers (KhronosGroup#5970)

* Fix layout checks with untyped pointers

* Handle the case where an untyped pointer represents a descriptor array
  * the array should not be required to have an array stride, but the
    element layout should be checked

* formatting

source/val/validate_decorations.cpp

@@ -1464,11 +1464,29 @@ spv_result_t CheckDecorationsOfBuffers(ValidationState_t& vstate) {
                      : (sc == spv::StorageClass::Workgroup ? "Workgroup"
                                                            : "StorageBuffer"));
 
-      const auto data_type = vstate.FindDef(data_type_id);
+      auto data_type = vstate.FindDef(data_type_id);
       scalar_block_layout =
           sc == spv::StorageClass::Workgroup
               ? vstate.options()->workgroup_scalar_block_layout
               : vstate.options()->scalar_block_layout;
+
+      // If the data type is an array that contains a Block- or
+      // BufferBlock-decorated struct, then use the struct for layout checks
+      // instead of the array. In this case, the array represents a descriptor
+      // array which should not have an explicit layout.
+      if (data_type->opcode() == spv::Op::OpTypeArray ||
+          data_type->opcode() == spv::Op::OpTypeRuntimeArray) {
+        const auto ele_type =
+            vstate.FindDef(data_type->GetOperandAs<uint32_t>(1u));
+        if (ele_type->opcode() == spv::Op::OpTypeStruct &&
+            (vstate.HasDecoration(ele_type->id(), spv::Decoration::Block) ||
+             vstate.HasDecoration(ele_type->id(),
+                                  spv::Decoration::BufferBlock))) {
+          data_type = ele_type;
+          data_type_id = ele_type->id();
+        }
+      }
+
       // Assume uniform storage class uses block rules unless we see a
       // BufferBlock decorated struct in the data type.
       bool bufferRules = sc == spv::StorageClass::Uniform ? false : true;

test/val/val_decoration_test.cpp

@@ -10696,6 +10696,67 @@ OpDecorate %array ArrayStride 4
                         "decorated with ArrayStride"));
 }
 
+TEST_F(ValidateDecorations, BlockArrayWithoutStride) {
+  const std::string spirv = R"(
+OpCapability Shader
+OpExtension "SPV_KHR_storage_buffer_storage_class"
+OpMemoryModel Logical GLSL450
+OpEntryPoint GLCompute %main "main"
+OpExecutionMode %main LocalSize 1 1 1
+OpDecorate %struct Block
+OpMemberDecorate %struct 0 Offset 0
+OpDecorate %var DescriptorSet 0
+OpDecorate %var Binding 0
+%int = OpTypeInt 32 0
+%int_4 = OpConstant %int 4
+%struct = OpTypeStruct %int
+%array = OpTypeArray %struct %int_4
+%ptr = OpTypePointer StorageBuffer %array
+%var = OpVariable %ptr StorageBuffer
+%void = OpTypeVoid
+%void_fn = OpTypeFunction %void
+%main = OpFunction %void None %void_fn
+%entry = OpLabel
+OpReturn
+OpFunctionEnd
+)";
+
+  CompileSuccessfully(spirv, SPV_ENV_VULKAN_1_0);
+  EXPECT_EQ(SPV_SUCCESS, ValidateInstructions(SPV_ENV_VULKAN_1_0));
+}
+
+TEST_F(ValidateDecorations, BlockArrayWithoutStrideUntypedAccessChain) {
+  const std::string spirv = R"(
+OpCapability Shader
+OpCapability UntypedPointersKHR
+OpExtension "SPV_KHR_storage_buffer_storage_class"
+OpExtension "SPV_KHR_untyped_pointers"
+OpMemoryModel Logical GLSL450
+OpEntryPoint GLCompute %main "main"
+OpExecutionMode %main LocalSize 1 1 1
+OpDecorate %struct Block
+OpMemberDecorate %struct 0 Offset 0
+OpDecorate %var DescriptorSet 0
+OpDecorate %var Binding 0
+%int = OpTypeInt 32 0
+%int_4 = OpConstant %int 4
+%struct = OpTypeStruct %int
+%array = OpTypeArray %struct %int_4
+%void = OpTypeVoid
+%ptr = OpTypeUntypedPointerKHR StorageBuffer
+%var = OpUntypedVariableKHR %ptr StorageBuffer %array
+%void_fn = OpTypeFunction %void
+%main = OpFunction %void None %void_fn
+%entry = OpLabel
+%gep = OpUntypedAccessChainKHR %ptr %array %var
+OpReturn
+OpFunctionEnd
+)";
+
+  CompileSuccessfully(spirv, SPV_ENV_VULKAN_1_0);
+  EXPECT_EQ(SPV_SUCCESS, ValidateInstructions(SPV_ENV_VULKAN_1_0));
+}
+
 }  // namespace
 }  // namespace val
 }  // namespace spvtools