[Fix, Test] (DirectVulkan, ShaderTranspiler, TraceReplay): repair iterationRP's missing reduction barrier

Program 203 reuses prefixSumCache for a second subgroup reduction before every workgroup invocation has consumed the first result. Add a fingerprint-gated SPIR-V pass that inserts the missing Workgroup acquire-release barrier while preserving native subgroup operations. Keep the repair opt-in behind MOBILEGL_ITERATIONRP_FIX_BARRIER, cover insertion, pass-through, and idempotence, and enable it together with the existing iterationRP subgroup repairs for the matching Linux and Android CI retraces.
2026-09-11 13:48:30 +09:00 · 2026-08-19 23:42:17 -04:00
parent 5bd8ef01e5
commit c09045fe59
20 changed files with 583 additions and 2 deletions
@@ -27,6 +27,7 @@
 #include "SpirvPasses/ZeroBaseVertexPass.h"
 #include "SpirvPasses/DeriveNumSubgroupsPass.h"
 #include "SpirvPasses/EmulateSubgroupsPass.h"
+#include "SpirvPasses/FixIterationRPBarrierPass.h"
 #include "SpirvPasses/FixIterationRPSubgroupScratchPass.h"
 #include "SpirvPasses/NormalizeRectCoordinatesPass.h"
 #include "SpirvPasses/Lower1DArrayImagesPass.h"
@@ -924,6 +925,17 @@ namespace MobileGL {
                                           inputBinary, outputBinary, true, enableSpirvValidation);
            }

+            bool ShaderCompiler::FixIterationRPBarrierForVulkan(
+                const Vector<Uint32>& inputBinary, Vector<uint32_t>& outputBinary,
+                const bool enableSpirvValidation) {
+                using namespace spvtools;
+                Optimizer optimizer(SPV_ENV_VULKAN_1_1);
+                optimizer.RegisterPass(FixIterationRPBarrierPass::CreateFixIterationRPBarrierPass());
+
+                return RunOptimizerChecked("FixIterationRPBarrierForVulkan", optimizer,
+                                           inputBinary, outputBinary, true, enableSpirvValidation);
+            }
+
            bool ShaderCompiler::DecoratePositionInvariantForVulkan(const Vector<Uint32>& inputBinary,
                                                                    Vector<uint32_t>& outputBinary, const bool enableSpirvValidation) {
                using namespace spvtools;
@@ -179,6 +179,12 @@ namespace MobileGL {
                                                                   Uint32 nativeSubgroupSize,
                                                                   Uint32 maxWorkgroupScratchBytes,
                                                                   bool enableSpirvValidation = false);
+                // Inserts the missing workgroup rendezvous between Program 203's two
+                // prefixSumCache reductions. Fingerprint-gated to the iterationRP shape;
+                // unrelated and already-repaired modules pass through byte-identical.
+                static bool FixIterationRPBarrierForVulkan(const Vector<Uint32>& inputBinary,
+                                                           Vector<uint32_t>& outputBinary,
+                                                           bool enableSpirvValidation = false);
                // Re-declares 64-bit float vertex inputs as their 32-bit unsigned word pair
                // (double -> uvec2, dvec2 -> uvec4) and bitcasts them back to double at entry, so no
                // VK_FORMAT_R64*_SFLOAT is needed - lavapipe advertises none of them for vertex
@@ -0,0 +1,232 @@
+// MobileGL - MobileGL/MG_Util/ShaderTranspiler/SpirvPasses/FixIterationRPBarrierPass.cpp
+// Copyright (c) 2026 MobileGL-Dev
+// Licensed under the GNU Lesser General Public License v3.0:
+//   https://www.gnu.org/licenses/gpl-3.0.txt
+//   https://www.gnu.org/licenses/lgpl-3.0.txt
+// SPDX-License-Identifier: LGPL-3.0-only
+// End of Source File Header
+
+#include "FixIterationRPBarrierPass.h"
+
+#include "spirv.hpp"
+#include "source/opt/constants.h"
+#include "source/opt/def_use_manager.h"
+#include "source/opt/instruction.h"
+#include "source/opt/ir_context.h"
+#include "source/opt/module.h"
+#include "source/util/make_unique.h"
+
+#include <vector>
+
+namespace MobileGL::MG_Util::ShaderTranspiler {
+    namespace {
+        using spvtools::opt::Instruction;
+        using spvtools::opt::IRContext;
+        using spvtools::opt::Operand;
+
+        const Instruction* RootVariable(IRContext* context, uint32_t pointerId) {
+            const Instruction* def = context->get_def_use_mgr()->GetDef(pointerId);
+            while (def != nullptr) {
+                switch (def->opcode()) {
+                case spv::Op::OpVariable:
+                    return def;
+                case spv::Op::OpAccessChain:
+                case spv::Op::OpInBoundsAccessChain:
+                case spv::Op::OpCopyObject:
+                    def = context->get_def_use_mgr()->GetDef(def->GetSingleWordInOperand(0));
+                    break;
+                default:
+                    return nullptr;
+                }
+            }
+            return nullptr;
+        }
+
+        bool IsUintConstant(IRContext* context, uint32_t id, uint32_t wanted) {
+            const Instruction* def = context->get_def_use_mgr()->GetDef(id);
+            return def != nullptr && def->opcode() == spv::Op::OpConstant && def->NumInOperands() == 1u &&
+                   def->GetSingleWordInOperand(0) == wanted;
+        }
+
+        bool IsZeroElementPointer(IRContext* context, uint32_t pointerId, const Instruction** root) {
+            const Instruction* pointer = context->get_def_use_mgr()->GetDef(pointerId);
+            if (pointer == nullptr ||
+                (pointer->opcode() != spv::Op::OpAccessChain && pointer->opcode() != spv::Op::OpInBoundsAccessChain) ||
+                pointer->NumInOperands() < 2u) {
+                return false;
+            }
+            for (uint32_t i = 1u; i < pointer->NumInOperands(); ++i) {
+                if (!IsUintConstant(context, pointer->GetSingleWordInOperand(i), 0u)) return false;
+            }
+            *root = RootVariable(context, pointerId);
+            return *root != nullptr;
+        }
+
+        bool IsWorkgroupVec2Array(IRContext* context, const Instruction* variable) {
+            if (variable == nullptr || variable->opcode() != spv::Op::OpVariable || variable->NumInOperands() < 1u ||
+                static_cast<spv::StorageClass>(variable->GetSingleWordInOperand(0)) != spv::StorageClass::Workgroup) {
+                return false;
+            }
+            auto* defUseMgr = context->get_def_use_mgr();
+            const Instruction* pointerType = defUseMgr->GetDef(variable->type_id());
+            if (pointerType == nullptr || pointerType->opcode() != spv::Op::OpTypePointer ||
+                pointerType->NumInOperands() < 2u) {
+                return false;
+            }
+            const Instruction* arrayType = defUseMgr->GetDef(pointerType->GetSingleWordInOperand(1));
+            if (arrayType == nullptr || arrayType->opcode() != spv::Op::OpTypeArray ||
+                arrayType->NumInOperands() < 2u) {
+                return false;
+            }
+            const Instruction* length = defUseMgr->GetDef(arrayType->GetSingleWordInOperand(1));
+            if (length == nullptr || length->opcode() != spv::Op::OpConstant || length->NumInOperands() != 1u) {
+                return false;
+            }
+            const uint32_t arrayLength = length->GetSingleWordInOperand(0);
+            if (arrayLength < 32u || arrayLength > 512u) return false;
+
+            const Instruction* vectorType = defUseMgr->GetDef(arrayType->GetSingleWordInOperand(0));
+            if (vectorType == nullptr || vectorType->opcode() != spv::Op::OpTypeVector ||
+                vectorType->NumInOperands() < 2u || vectorType->GetSingleWordInOperand(1) != 2u) {
+                return false;
+            }
+            const Instruction* scalarType = defUseMgr->GetDef(vectorType->GetSingleWordInOperand(0));
+            return scalarType != nullptr && scalarType->opcode() == spv::Op::OpTypeFloat &&
+                   scalarType->NumInOperands() == 1u && scalarType->GetSingleWordInOperand(0) == 32u;
+        }
+
+        bool IsVec2FloatInclusiveAdd(IRContext* context, const Instruction* inst) {
+            if (inst->opcode() != spv::Op::OpGroupNonUniformFAdd || inst->NumInOperands() < 3u ||
+                static_cast<spv::GroupOperation>(inst->GetSingleWordInOperand(1)) !=
+                    spv::GroupOperation::InclusiveScan) {
+                return false;
+            }
+            const Instruction* vectorType = context->get_def_use_mgr()->GetDef(inst->type_id());
+            if (vectorType == nullptr || vectorType->opcode() != spv::Op::OpTypeVector ||
+                vectorType->NumInOperands() < 2u || vectorType->GetSingleWordInOperand(1) != 2u) {
+                return false;
+            }
+            const Instruction* scalarType = context->get_def_use_mgr()->GetDef(vectorType->GetSingleWordInOperand(0));
+            return scalarType != nullptr && scalarType->opcode() == spv::Op::OpTypeFloat &&
+                   scalarType->NumInOperands() == 1u && scalarType->GetSingleWordInOperand(0) == 32u;
+        }
+
+        bool HasProgram203LocalSize(IRContext* context) {
+            for (const Instruction& entryPoint : context->module()->entry_points()) {
+                if (static_cast<spv::ExecutionModel>(entryPoint.GetSingleWordInOperand(0)) !=
+                    spv::ExecutionModel::GLCompute) {
+                    return false;
+                }
+            }
+            for (const Instruction& mode : context->module()->execution_modes()) {
+                if (mode.opcode() == spv::Op::OpExecutionMode && mode.NumInOperands() >= 5u &&
+                    static_cast<spv::ExecutionMode>(mode.GetSingleWordInOperand(1)) == spv::ExecutionMode::LocalSize) {
+                    return mode.GetSingleWordInOperand(2) == 32u && mode.GetSingleWordInOperand(3) == 16u &&
+                           mode.GetSingleWordInOperand(4) == 1u;
+                }
+            }
+            return false;
+        }
+
+        bool IsStoreToRoot(IRContext* context, const Instruction* inst, const Instruction* root) {
+            return inst->opcode() == spv::Op::OpStore && inst->NumInOperands() >= 2u &&
+                   RootVariable(context, inst->GetSingleWordInOperand(0)) == root;
+        }
+    } // namespace
+
+    spvtools::opt::Pass::Status FixIterationRPBarrierPass::Process() {
+        auto* irContext = context();
+        if (!HasProgram203LocalSize(irContext)) return Status::SuccessWithoutChange;
+
+        for (auto& function : *irContext->module()) {
+            std::vector<Instruction*> instructions;
+            std::vector<size_t> scans;
+            for (auto& block : function) {
+                for (auto& inst : block) {
+                    if (IsVec2FloatInclusiveAdd(irContext, &inst)) scans.push_back(instructions.size());
+                    instructions.push_back(&inst);
+                }
+            }
+            // Program 203 has exactly two vec2 inclusive adds: the luminance reduction
+            // and the weighted-exposure reduction. More or fewer is not our fingerprint.
+            if (scans.size() != 2u) continue;
+
+            const size_t firstScan = scans[0];
+            const size_t secondScan = scans[1];
+            const Instruction* scratch = nullptr;
+            size_t averageLoad = instructions.size();
+
+            for (size_t i = firstScan + 1u; i < secondScan; ++i) {
+                Instruction* inst = instructions[i];
+                if (inst->opcode() != spv::Op::OpLoad || inst->NumInOperands() < 1u) continue;
+                const Instruction* root = nullptr;
+                if (!IsZeroElementPointer(irContext, inst->GetSingleWordInOperand(0), &root) ||
+                    !IsWorkgroupVec2Array(irContext, root)) {
+                    continue;
+                }
+                // The broadcast is read as prefixSumCache[0].x, hence a scalar load.
+                const Instruction* type = irContext->get_def_use_mgr()->GetDef(inst->type_id());
+                if (type == nullptr || type->opcode() != spv::Op::OpTypeFloat || type->NumInOperands() != 1u ||
+                    type->GetSingleWordInOperand(0) != 32u) {
+                    continue;
+                }
+                scratch = root;
+                averageLoad = i;
+                break;
+            }
+            if (scratch == nullptr) continue;
+
+            bool sawZeroBroadcastStore = false;
+            bool sawPublishBarrier = false;
+            for (size_t i = firstScan + 1u; i < averageLoad; ++i) {
+                const Instruction* root = nullptr;
+                if (instructions[i]->opcode() == spv::Op::OpStore &&
+                    IsZeroElementPointer(irContext, instructions[i]->GetSingleWordInOperand(0), &root) &&
+                    root == scratch) {
+                    sawZeroBroadcastStore = true;
+                } else if (sawZeroBroadcastStore && instructions[i]->opcode() == spv::Op::OpControlBarrier) {
+                    sawPublishBarrier = true;
+                }
+            }
+            if (!sawZeroBroadcastStore || !sawPublishBarrier) continue;
+
+            bool alreadySynchronized = false;
+            for (size_t i = averageLoad + 1u; i < secondScan; ++i) {
+                if (instructions[i]->opcode() == spv::Op::OpControlBarrier) {
+                    alreadySynchronized = true;
+                    break;
+                }
+            }
+            if (alreadySynchronized) return Status::SuccessWithoutChange;
+
+            bool secondPhaseReusesScratch = false;
+            for (size_t i = secondScan + 1u; i < instructions.size(); ++i) {
+                if (IsStoreToRoot(irContext, instructions[i], scratch)) {
+                    secondPhaseReusesScratch = true;
+                    break;
+                }
+            }
+            if (!secondPhaseReusesScratch) continue;
+
+            auto* constantMgr = irContext->get_constant_mgr();
+            const uint32_t scopeId = constantMgr->GetUIntConstId(static_cast<uint32_t>(spv::Scope::Workgroup));
+            const uint32_t semanticsId =
+                constantMgr->GetUIntConstId(static_cast<uint32_t>(spv::MemorySemanticsMask::AcquireRelease) |
+                                            static_cast<uint32_t>(spv::MemorySemanticsMask::WorkgroupMemory));
+            if (scopeId == 0u || semanticsId == 0u) return Status::Failure;
+
+            instructions[secondScan]->InsertBefore(spvtools::MakeUnique<Instruction>(
+                irContext, spv::Op::OpControlBarrier, 0u, 0u,
+                Instruction::OperandList{Operand{SPV_OPERAND_TYPE_ID, {scopeId}},
+                                         Operand{SPV_OPERAND_TYPE_ID, {scopeId}},
+                                         Operand{SPV_OPERAND_TYPE_ID, {semanticsId}}}));
+            irContext->InvalidateAnalysesExceptFor(IRContext::kAnalysisNone);
+            return Status::SuccessWithChange;
+        }
+        return Status::SuccessWithoutChange;
+    }
+
+    spvtools::Optimizer::PassToken FixIterationRPBarrierPass::CreateFixIterationRPBarrierPass() {
+        return spvtools::Optimizer::PassToken(spvtools::MakeUnique<FixIterationRPBarrierPass>());
+    }
+} // namespace MobileGL::MG_Util::ShaderTranspiler
@@ -0,0 +1,28 @@
+// MobileGL - MobileGL/MG_Util/ShaderTranspiler/SpirvPasses/FixIterationRPBarrierPass.h
+// Copyright (c) 2026 MobileGL-Dev
+// Licensed under the GNU Lesser General Public License v3.0:
+//   https://www.gnu.org/licenses/gpl-3.0.txt
+//   https://www.gnu.org/licenses/lgpl-3.0.txt
+// SPDX-License-Identifier: LGPL-3.0-only
+// End of Source File Header
+
+#pragma once
+
+#include "source/opt/pass.h"
+#include "spirv-tools/optimizer.hpp"
+
+namespace MobileGL::MG_Util::ShaderTranspiler {
+    // Repairs iterationRP Program 203's missing workgroup rendezvous between two
+    // reductions that reuse prefixSumCache. The first phase broadcasts its result
+    // through prefixSumCache[0], but the second phase may overwrite that element before
+    // every invocation has read it. The pass fingerprints that exact two-scan,
+    // 512-invocation shape and inserts one Workgroup control barrier immediately before
+    // the second scan. Unrelated modules and already-repaired modules are byte-identical.
+    class FixIterationRPBarrierPass : public spvtools::opt::Pass {
+    public:
+        const char* name() const override { return "fix-iterationrp-barrier"; }
+        Status Process() override;
+
+        static spvtools::Optimizer::PassToken CreateFixIterationRPBarrierPass();
+    };
+} // namespace MobileGL::MG_Util::ShaderTranspiler