forked from OSchip/llvm-project
125 lines
4.3 KiB
C++
125 lines
4.3 KiB
C++
//===- Bufferize.cpp - Bufferization for std ops --------------------------===//
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//
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// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
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// See https://llvm.org/LICENSE.txt for license information.
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// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
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//
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//===----------------------------------------------------------------------===//
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//
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// This file implements bufferization of tensor-valued std.constant ops.
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//
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//===----------------------------------------------------------------------===//
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#include "PassDetail.h"
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#include "mlir/Dialect/StandardOps/IR/Ops.h"
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#include "mlir/Dialect/StandardOps/Transforms/Passes.h"
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#include "mlir/IR/BlockAndValueMapping.h"
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#include "mlir/Transforms/Bufferize.h"
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#include "mlir/Transforms/DialectConversion.h"
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using namespace mlir;
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namespace {
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// This class creates global ops for all tensor-valued constants in the program.
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// It creates them with pretty names and makes sure that duplicate globals
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// aren't created.
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class GlobalCreator {
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public:
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explicit GlobalCreator(ModuleOp module);
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GlobalMemrefOp getGlobalFor(Attribute attr) {
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assert(globals.find(attr) != globals.end() && "unknown constant attr");
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return globals[attr];
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}
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private:
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DenseMap<Attribute, GlobalMemrefOp> globals;
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};
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GlobalCreator::GlobalCreator(ModuleOp module) {
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BufferizeTypeConverter typeConverter;
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// Create a builder without an insertion point. We will insert using the
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// symbol table to guarantee unique names.
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OpBuilder globalBuilder(module.getContext());
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SymbolTable symbolTable(module);
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module.walk([&](ConstantOp op) {
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// We only want tensor constants for now.
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auto type = op.getType().dyn_cast<RankedTensorType>();
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if (!type)
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return;
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// If we already have a global for this constant value, no need to do
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// anything else.
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auto it = globals.find(op.getValue());
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if (it != globals.end())
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return;
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// Create a pretty name.
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SmallString<64> buf;
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llvm::raw_svector_ostream os(buf);
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interleave(type.getShape(), os, "x");
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os << "x" << type.getElementType();
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auto global = globalBuilder.create<GlobalMemrefOp>(
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op.getLoc(), (Twine("__constant_") + os.str()).str(),
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/*sym_visibility=*/globalBuilder.getStringAttr("private"),
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/*type=*/typeConverter.convertType(type),
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/*initial_value=*/op.getValue().cast<ElementsAttr>(),
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/*constant=*/true);
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symbolTable.insert(global);
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// The symbol table inserts at the end of the module, but globals are a bit
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// nicer if they are at the beginning.
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global->moveBefore(&module.front());
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globals[op.getValue()] = global;
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});
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}
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} // namespace
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namespace {
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class BufferizeTensorConstantOp : public OpConversionPattern<ConstantOp> {
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public:
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BufferizeTensorConstantOp(GlobalCreator &globals,
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TypeConverter &typeConverter, MLIRContext *context)
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: OpConversionPattern<ConstantOp>(typeConverter, context, /*benefit=*/1),
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globals(globals) {}
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LogicalResult
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matchAndRewrite(ConstantOp op, ArrayRef<Value> operands,
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ConversionPatternRewriter &rewriter) const override {
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auto type = op.getType().dyn_cast<RankedTensorType>();
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if (!type)
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return failure();
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auto globalMemref = globals.getGlobalFor(op.value());
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rewriter.replaceOpWithNewOp<GetGlobalMemrefOp>(op, globalMemref.type(),
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globalMemref.getName());
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return success();
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}
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GlobalCreator &globals;
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};
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} // namespace
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namespace {
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struct TensorConstantBufferizePass
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: public TensorConstantBufferizeBase<TensorConstantBufferizePass> {
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void runOnOperation() override {
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auto module = getOperation();
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GlobalCreator globals(module);
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auto *context = &getContext();
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BufferizeTypeConverter typeConverter;
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OwningRewritePatternList patterns;
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ConversionTarget target(*context);
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target.addLegalDialect<StandardOpsDialect>();
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patterns.insert<BufferizeTensorConstantOp>(globals, typeConverter, context);
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target.addDynamicallyLegalOp<ConstantOp>(
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[&](ConstantOp op) { return typeConverter.isLegal(op.getType()); });
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if (failed(applyPartialConversion(module, target, std::move(patterns))))
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signalPassFailure();
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}
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};
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} // namespace
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std::unique_ptr<Pass> mlir::createTensorConstantBufferizePass() {
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return std::make_unique<TensorConstantBufferizePass>();
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}
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