layers/gpuav/shaders/gpuav_shaders_constants.h

// Copyright (c) 2021-2026 The Khronos Group Inc.
// Copyright (c) 2021-2026 Valve Corporation
// Copyright (c) 2021-2026 LunarG, Inc.
// Copyright (c) 2025 Arm Limited.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//     http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
// Values used between the GLSL shaders and the GPU-AV logic

// NOTE: This header is included by the instrumentation shaders and glslang doesn't support #pragma once
#ifndef GPU_SHADERS_CONSTANTS_H
#define GPU_SHADERS_CONSTANTS_H

#ifdef __cplusplus
namespace gpuav {
namespace glsl {
using uint = unsigned int;

// Upper bound for maxUpdateAfterBindDescriptorsInAllPools. This value needs to
// be small enough to allow for a table in memory, but some devices set it to 2^32.
// This value only matters for host code, but it is defined here so it can be used
// in unit tests.
const uint kDebugInputBindlessMaxDescriptors = 1024u * 1024u * 4u;

#endif

// Maximum errors a cmd is allowed to log
const uint kMaxErrorsPerCmd = 6;

// Instrumentation
// ---

// Instead of having to create a variable and pass it in each time for every function call made, we use these values to map
// constants in the GLSL to be updated with constant values known when we are doing the linking at GPU-AV runtime.
// (Basically our own implementaiton of Specialization Constant)
const uint kLinkShaderId = 0x0DEAD001;
const uint kInstErrorBufferLengthId = 0x0DEAD002;

// This is just a placeholder, honestly could be anything, will be replaced when linking to the runtime descriptor set choosen
const int kInstDefaultDescriptorSet = 7;

// Binding index inside the descriptor set used by instrumentation validation.
// Set to front as people might want to use only DebugPrintf and this can allow us to reduce overhead not binding the other buffers
const int kBindingInstDebugPrintf = 0;
// binding #1 is reserved for the output all non-DebugPrintf shaders write out too.
const int kBindingInstErrorBuffer = 1;
// An output binding to get info off the GPU and run on the CPU
const int kBindingInstPostProcess = 2;
// Each check that requires additional input to be sent must reserve its own binding slot
const int kBindingInstDescriptorIndexingOOB = 3;
const int kBindingInstBufferDeviceAddress = 4;
const int kBindingInstActionIndex = 5;
const int kBindingInstCmdResourceIndex = 6;
const int kBindingInstCmdErrorsCount = 7;
const int kBindingInstVertexAttributeFetchLimits = 8;
const int kBindingInstDebugDescriptor = 9;
const int kTotalBindings = 10;

// Validation pipelines
// ---
const int kValPipeDescSet = 0;

// Diagnostic calls
// ---
const int kDiagCommonDescriptorSet = kValPipeDescSet + 1;

// Diagnostic calls bindings in common descriptor set
const int kBindingDiagErrorBuffer = 0;
const int kBindingDiagActionIndex = 1;
const int kBindingDiagCmdResourceIndex = 2;
const int kBindingDiagCmdErrorsCount = 3;

// Direct Input Buffer Offsets
//
// The following values provide member offsets into the input buffers
// consumed by InstrumentPass::GenDebugDirectRead(). This method is utilized
// by InstBindlessCheckPass.
//
// The only object in an input buffer is a runtime array of unsigned
// integers. Each validation will have its own formatting of this array.
const int kDebugInputDataOffset = 0;

// The size of the inst_bindless_input_buffer array, regardless of how many
// descriptor sets the device supports.
const int kDebugInputBindlessMaxDescSets = 32;

// Used to know that the descriptor is null and not uninitialized
const uint kNullDescriptor = 0x00ffffff;

// Top 8 bits of the descriptor id
const uint kDescBitShift = 24;
const uint kSamplerDesc = 1;
const uint kImageSamplerDesc = 2;
const uint kImageDesc = 3;
const uint kTexelDesc = 4;
const uint kBufferDesc = 5;
const uint kInlineUniformDesc = 6;
const uint kAccelDesc = 7;
const uint kTensorDesc = 8;

// Buffer Device Address Input Buffer Format
//
// An input buffer for buffer device address validation consists of a single
// array of unsigned 64-bit integers we will call Data[]. This array is
// formatted as follows:
//
// At offset kDebugInputBuffAddrPtrOffset is a list of sorted valid buffer
// addresses. The list is terminated with the address 0xffffffffffffffff.
// If 0x0 is not a valid buffer address, this address is inserted at the
// start of the list.
//
const int kDebugInputBuffAddrPtrOffset = 1;
//
// At offset kDebugInputBuffAddrLengthOffset in Data[] is a single uint64 which
// gives an offset to the start of the buffer length data. More
// specifically, for a buffer whose pointer is located at input buffer offset
// i, the length is located at:
//
// Data[ i - kDebugInputBuffAddrPtrOffset
//         + Data[ kDebugInputBuffAddrLengthOffset ] ]
//
// The length associated with the 0xffffffffffffffff address is zero. If
// not a valid buffer, the length associated with the 0x0 address is zero.
const int kDebugInputBuffAddrLengthOffset = 0;

// Current layout for the meta_data dword
// |     31      | 30 .......... 18 | 17 ................. 0 |
// | is accessed | Action Cmd Index | Instrumented Shader Id |
//
// We make some assumptions from profiling that we can maintain these limits and squeeze all this information in a single dword
// these values are asserted for and can be adjusted if we edge cases that matter
//
// cst::indices_count is set at 1u << 13 (8192) used to set the action cmd index
//
// // We use a single bit mark if this descriptor was accessed or not
const uint kPostProcessMetaMaskAccessed = 1u << 31;
const uint kPostProcessMetaShiftErrorLoggerIndex = 18;
const uint kPostProcessMetaMaskErrorLoggerIndex = 0x1FFF << kPostProcessMetaShiftErrorLoggerIndex;

// Shared Memory Data Race
//  Shadow word encoding
//   [31..29] flags (STORE_BIT, ATOMIC_BIT, MULTI_LOAD_BIT)
//   [28..12] inst_offset (17 bits, word offset of the accessing SPIR-V instruction)
//   [11..0]  thread_id (12 bits)
const uint kSharedMemoryDataRace_InstOffsetShift = 12u;
const uint kSharedMemoryDataRace_ThreadIdMask = 0x00000FFFu;    // bits 11..0
const uint kSharedMemoryDataRace_InstOffsetMask = 0x1FFFF000u;  // bits 28..12
const uint kSharedMemoryDataRace_InstOffsetBits = 0x1FFFFu;
const uint kSharedMemoryDataRace_InstOffsetMax = kSharedMemoryDataRace_InstOffsetBits - 1;  // 0x1FFFF reserved

#ifdef __cplusplus
}  // namespace glsl
}  // namespace gpuav
#endif
#endif