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| 1 | +//===- ModuleCombiner.cpp - MLIR SPIR-V Module Combiner ---------*- C++ -*-===// |
| 2 | +// |
| 3 | +// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. |
| 4 | +// See https://llvm.org/LICENSE.txt for license information. |
| 5 | +// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception |
| 6 | +// |
| 7 | +//===----------------------------------------------------------------------===// |
| 8 | +// |
| 9 | +// This file implements the the SPIR-V module combiner library. |
| 10 | +// |
| 11 | +//===----------------------------------------------------------------------===// |
| 12 | + |
| 13 | +#include "mlir/Dialect/SPIRV/ModuleCombiner.h" |
| 14 | + |
| 15 | +#include "mlir/Dialect/SPIRV/SPIRVOps.h" |
| 16 | +#include "mlir/IR/Builders.h" |
| 17 | +#include "mlir/IR/SymbolTable.h" |
| 18 | +#include "llvm/ADT/ArrayRef.h" |
| 19 | +#include "llvm/ADT/StringExtras.h" |
| 20 | + |
| 21 | +using namespace mlir; |
| 22 | + |
| 23 | +static constexpr unsigned maxFreeID = 1 << 20; |
| 24 | + |
| 25 | +static SmallString<64> renameSymbol(StringRef oldSymName, unsigned &lastUsedID, |
| 26 | + spirv::ModuleOp combinedModule) { |
| 27 | + SmallString<64> newSymName(oldSymName); |
| 28 | + newSymName.push_back('_'); |
| 29 | + |
| 30 | + while (lastUsedID < maxFreeID) { |
| 31 | + std::string possible = (newSymName + llvm::utostr(++lastUsedID)).str(); |
| 32 | + |
| 33 | + if (!SymbolTable::lookupSymbolIn(combinedModule, possible)) { |
| 34 | + newSymName += llvm::utostr(lastUsedID); |
| 35 | + break; |
| 36 | + } |
| 37 | + } |
| 38 | + |
| 39 | + return newSymName; |
| 40 | +} |
| 41 | + |
| 42 | +/// Check if a symbol with the same name as op already exists in source. If so, |
| 43 | +/// rename op and update all its references in target. |
| 44 | +static LogicalResult updateSymbolAndAllUses(SymbolOpInterface op, |
| 45 | + spirv::ModuleOp target, |
| 46 | + spirv::ModuleOp source, |
| 47 | + unsigned &lastUsedID) { |
| 48 | + if (!SymbolTable::lookupSymbolIn(source, op.getName())) |
| 49 | + return success(); |
| 50 | + |
| 51 | + StringRef oldSymName = op.getName(); |
| 52 | + SmallString<64> newSymName = renameSymbol(oldSymName, lastUsedID, target); |
| 53 | + |
| 54 | + if (failed(SymbolTable::replaceAllSymbolUses(op, newSymName, target))) |
| 55 | + return op.emitError("unable to update all symbol uses for ") |
| 56 | + << oldSymName << " to " << newSymName; |
| 57 | + |
| 58 | + SymbolTable::setSymbolName(op, newSymName); |
| 59 | + return success(); |
| 60 | +} |
| 61 | + |
| 62 | +namespace mlir { |
| 63 | +namespace spirv { |
| 64 | + |
| 65 | +// TODO Properly test symbol rename listener mechanism. |
| 66 | + |
| 67 | +OwningSPIRVModuleRef |
| 68 | +combine(llvm::MutableArrayRef<spirv::ModuleOp> modules, |
| 69 | + OpBuilder &combinedModuleBuilder, |
| 70 | + llvm::function_ref<void(ModuleOp, StringRef, StringRef)> |
| 71 | + symRenameListener) { |
| 72 | + unsigned lastUsedID = 0; |
| 73 | + |
| 74 | + if (modules.empty()) |
| 75 | + return nullptr; |
| 76 | + |
| 77 | + auto addressingModel = modules[0].addressing_model(); |
| 78 | + auto memoryModel = modules[0].memory_model(); |
| 79 | + |
| 80 | + auto combinedModule = combinedModuleBuilder.create<spirv::ModuleOp>( |
| 81 | + modules[0].getLoc(), addressingModel, memoryModel); |
| 82 | + combinedModuleBuilder.setInsertionPointToStart(&*combinedModule.getBody()); |
| 83 | + |
| 84 | + // In some cases, a symbol in the (current state of the) combined module is |
| 85 | + // renamed in order to maintain the conflicting symbol in the input module |
| 86 | + // being merged. For example, if the conflict is between a global variable in |
| 87 | + // the current combined module and a function in the input module, the global |
| 88 | + // varaible is renamed. In order to notify listeners of the symbol updates in |
| 89 | + // such cases, we need to keep track of the module from which the renamed |
| 90 | + // symbol in the combined module originated. This map keeps such information. |
| 91 | + DenseMap<StringRef, spirv::ModuleOp> symNameToModuleMap; |
| 92 | + |
| 93 | + for (auto module : modules) { |
| 94 | + if (module.addressing_model() != addressingModel || |
| 95 | + module.memory_model() != memoryModel) { |
| 96 | + module.emitError( |
| 97 | + "input modules differ in addressing model and/or memory model"); |
| 98 | + return nullptr; |
| 99 | + } |
| 100 | + |
| 101 | + spirv::ModuleOp moduleClone = module.clone(); |
| 102 | + |
| 103 | + // In the combined module, rename all symbols that conflict with symbols |
| 104 | + // from the current input module. This renmaing applies to all ops except |
| 105 | + // for spv.funcs. This way, if the conflicting op in the input module is |
| 106 | + // non-spv.func, we rename that symbol instead and maintain the spv.func in |
| 107 | + // the combined module name as it is. |
| 108 | + for (auto &op : combinedModule.getBlock().without_terminator()) { |
| 109 | + if (auto symbolOp = dyn_cast<SymbolOpInterface>(op)) { |
| 110 | + StringRef oldSymName = symbolOp.getName(); |
| 111 | + |
| 112 | + if (!isa<FuncOp>(op) && |
| 113 | + failed(updateSymbolAndAllUses(symbolOp, combinedModule, moduleClone, |
| 114 | + lastUsedID))) |
| 115 | + return nullptr; |
| 116 | + |
| 117 | + StringRef newSymName = symbolOp.getName(); |
| 118 | + |
| 119 | + if (symRenameListener && oldSymName != newSymName) { |
| 120 | + spirv::ModuleOp originalModule = |
| 121 | + symNameToModuleMap.lookup(oldSymName); |
| 122 | + |
| 123 | + if (!originalModule) { |
| 124 | + module.emitError("unable to find original ModuleOp for symbol ") |
| 125 | + << oldSymName; |
| 126 | + return nullptr; |
| 127 | + } |
| 128 | + |
| 129 | + symRenameListener(originalModule, oldSymName, newSymName); |
| 130 | + |
| 131 | + // Since the symbol name is updated, there is no need to maintain the |
| 132 | + // entry that assocaites the old symbol name with the original module. |
| 133 | + symNameToModuleMap.erase(oldSymName); |
| 134 | + // Instead, add a new entry to map the new symbol name to the original |
| 135 | + // module in case it gets renamed again later. |
| 136 | + symNameToModuleMap[newSymName] = originalModule; |
| 137 | + } |
| 138 | + } |
| 139 | + } |
| 140 | + |
| 141 | + // In the current input module, rename all symbols that conflict with |
| 142 | + // symbols from the combined module. This includes renaming spv.funcs. |
| 143 | + for (auto &op : moduleClone.getBlock().without_terminator()) { |
| 144 | + if (auto symbolOp = dyn_cast<SymbolOpInterface>(op)) { |
| 145 | + StringRef oldSymName = symbolOp.getName(); |
| 146 | + |
| 147 | + if (failed(updateSymbolAndAllUses(symbolOp, moduleClone, combinedModule, |
| 148 | + lastUsedID))) |
| 149 | + return nullptr; |
| 150 | + |
| 151 | + StringRef newSymName = symbolOp.getName(); |
| 152 | + |
| 153 | + if (symRenameListener && oldSymName != newSymName) { |
| 154 | + symRenameListener(module, oldSymName, newSymName); |
| 155 | + |
| 156 | + // Insert the module associated with the symbol name. |
| 157 | + auto emplaceResult = |
| 158 | + symNameToModuleMap.try_emplace(symbolOp.getName(), module); |
| 159 | + |
| 160 | + // If an entry with the same symbol name is already present, this must |
| 161 | + // be a problem with the implementation, specially clean-up of the map |
| 162 | + // while iterating over the combined module above. |
| 163 | + if (!emplaceResult.second) { |
| 164 | + module.emitError("did not expect to find an entry for symbol ") |
| 165 | + << symbolOp.getName(); |
| 166 | + return nullptr; |
| 167 | + } |
| 168 | + } |
| 169 | + } |
| 170 | + } |
| 171 | + |
| 172 | + // Clone all the module's ops to the combined module. |
| 173 | + for (auto &op : moduleClone.getBlock().without_terminator()) |
| 174 | + combinedModuleBuilder.insert(op.clone()); |
| 175 | + } |
| 176 | + |
| 177 | + return combinedModule; |
| 178 | +} |
| 179 | + |
| 180 | +} // namespace spirv |
| 181 | +} // namespace mlir |
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