llvm-project/mlir/lib/Dialect/Bufferization/Transforms/Bufferize.cpp

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18 KiB
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//===- Bufferize.cpp - Bufferization utilities ----------------------------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
#include "PassDetail.h"
#include "mlir/Dialect/Bufferization/IR/BufferizableOpInterface.h"
#include "mlir/Dialect/Bufferization/IR/Bufferization.h"
#include "mlir/Dialect/Bufferization/Transforms/Bufferize.h"
#include "mlir/Dialect/Bufferization/Transforms/OneShotAnalysis.h"
#include "mlir/Dialect/Bufferization/Transforms/OneShotModuleBufferize.h"
#include "mlir/Dialect/Bufferization/Transforms/Passes.h"
#include "mlir/Dialect/Bufferization/Transforms/TensorCopyInsertion.h"
#include "mlir/Dialect/Func/IR/FuncOps.h"
#include "mlir/Dialect/MemRef/IR/MemRef.h"
#include "mlir/IR/Operation.h"
#include "mlir/Pass/PassManager.h"
#include "mlir/Transforms/GreedyPatternRewriteDriver.h"
#include "mlir/Transforms/Passes.h"
using namespace mlir;
using namespace mlir::bufferization;
//===----------------------------------------------------------------------===//
// BufferizeTypeConverter
//===----------------------------------------------------------------------===//
static Value materializeToTensor(OpBuilder &builder, TensorType type,
ValueRange inputs, Location loc) {
assert(inputs.size() == 1);
assert(inputs[0].getType().isa<BaseMemRefType>());
return builder.create<bufferization::ToTensorOp>(loc, type, inputs[0]);
}
/// Registers conversions into BufferizeTypeConverter
BufferizeTypeConverter::BufferizeTypeConverter() {
// Keep all types unchanged.
addConversion([](Type type) { return type; });
// Convert RankedTensorType to MemRefType.
addConversion([](RankedTensorType type) -> Type {
return MemRefType::get(type.getShape(), type.getElementType());
});
// Convert UnrankedTensorType to UnrankedMemRefType.
addConversion([](UnrankedTensorType type) -> Type {
return UnrankedMemRefType::get(type.getElementType(), 0);
});
addArgumentMaterialization(materializeToTensor);
addSourceMaterialization(materializeToTensor);
addTargetMaterialization([](OpBuilder &builder, BaseMemRefType type,
ValueRange inputs, Location loc) -> Value {
assert(inputs.size() == 1 && "expected exactly one input");
if (auto inputType = inputs[0].getType().dyn_cast<MemRefType>()) {
// MemRef to MemRef cast.
assert(inputType != type && "expected different types");
// Unranked to ranked and ranked to unranked casts must be explicit.
auto rankedDestType = type.dyn_cast<MemRefType>();
if (!rankedDestType)
return nullptr;
FailureOr<Value> replacement =
castOrReallocMemRefValue(builder, inputs[0], rankedDestType);
if (failed(replacement))
return nullptr;
return *replacement;
}
if (inputs[0].getType().isa<TensorType>()) {
// Tensor to MemRef cast.
return builder.create<bufferization::ToMemrefOp>(loc, type, inputs[0]);
}
llvm_unreachable("only tensor/memref input types supported");
});
}
void mlir::bufferization::populateBufferizeMaterializationLegality(
ConversionTarget &target) {
target.addLegalOp<bufferization::ToTensorOp, bufferization::ToMemrefOp>();
}
namespace {
// In a finalizing bufferize conversion, we know that all tensors have been
// converted to memrefs, thus, this op becomes an identity.
class BufferizeToTensorOp
: public OpConversionPattern<bufferization::ToTensorOp> {
public:
using OpConversionPattern::OpConversionPattern;
LogicalResult
matchAndRewrite(bufferization::ToTensorOp op, OpAdaptor adaptor,
ConversionPatternRewriter &rewriter) const override {
rewriter.replaceOp(op, adaptor.getMemref());
return success();
}
};
} // namespace
namespace {
// In a finalizing bufferize conversion, we know that all tensors have been
// converted to memrefs, thus, this op becomes an identity.
class BufferizeToMemrefOp
: public OpConversionPattern<bufferization::ToMemrefOp> {
public:
using OpConversionPattern::OpConversionPattern;
LogicalResult
matchAndRewrite(bufferization::ToMemrefOp op, OpAdaptor adaptor,
ConversionPatternRewriter &rewriter) const override {
rewriter.replaceOp(op, adaptor.getTensor());
return success();
}
};
} // namespace
void mlir::bufferization::populateEliminateBufferizeMaterializationsPatterns(
BufferizeTypeConverter &typeConverter, RewritePatternSet &patterns) {
patterns.add<BufferizeToTensorOp, BufferizeToMemrefOp>(typeConverter,
patterns.getContext());
}
namespace {
struct FinalizingBufferizePass
: public FinalizingBufferizeBase<FinalizingBufferizePass> {
using FinalizingBufferizeBase<
FinalizingBufferizePass>::FinalizingBufferizeBase;
void runOnOperation() override {
auto func = getOperation();
auto *context = &getContext();
BufferizeTypeConverter typeConverter;
RewritePatternSet patterns(context);
ConversionTarget target(*context);
populateEliminateBufferizeMaterializationsPatterns(typeConverter, patterns);
// If all result types are legal, and all block arguments are legal (ensured
// by func conversion above), then all types in the program are legal.
//
// We also check that the operand types are legal to avoid creating invalid
// IR. For example, this prevents
// populateEliminateBufferizeMaterializationsPatterns from updating the
// types of the operands to a return op without updating the enclosing
// function.
target.markUnknownOpDynamicallyLegal(
[&](Operation *op) { return typeConverter.isLegal(op); });
if (failed(applyFullConversion(func, target, std::move(patterns))))
signalPassFailure();
}
};
static BufferizationOptions::LayoutMapOption
parseLayoutMapOption(const std::string &s) {
if (s == "fully-dynamic-layout-map")
return BufferizationOptions::LayoutMapOption::FullyDynamicLayoutMap;
if (s == "identity-layout-map")
return BufferizationOptions::LayoutMapOption::IdentityLayoutMap;
if (s == "infer-layout-map")
return BufferizationOptions::LayoutMapOption::InferLayoutMap;
llvm_unreachable("invalid layout map option");
}
struct OneShotBufferizePass
: public OneShotBufferizeBase<OneShotBufferizePass> {
OneShotBufferizePass() : OneShotBufferizeBase<OneShotBufferizePass>() {}
explicit OneShotBufferizePass(const OneShotBufferizationOptions &options)
: options(options) {}
void getDependentDialects(DialectRegistry &registry) const override {
registry
.insert<bufferization::BufferizationDialect, memref::MemRefDialect>();
registerAllocationOpInterfaceExternalModels(registry);
}
void runOnOperation() override {
OneShotBufferizationOptions opt;
if (!options) {
// Make new bufferization options if none were provided when creating the
// pass.
opt.allowReturnAllocs = allowReturnAllocs;
opt.allowUnknownOps = allowUnknownOps;
opt.analysisFuzzerSeed = analysisFuzzerSeed;
opt.createDeallocs = createDeallocs;
opt.functionBoundaryTypeConversion =
parseLayoutMapOption(functionBoundaryTypeConversion);
if (mustInferMemorySpace)
opt.defaultMemorySpace = None;
opt.printConflicts = printConflicts;
opt.testAnalysisOnly = testAnalysisOnly;
opt.bufferizeFunctionBoundaries = bufferizeFunctionBoundaries;
// Configure type converter.
BufferizationOptions::LayoutMapOption unknownTypeConversionOption =
parseLayoutMapOption(unknownTypeConversion);
opt.unknownTypeConverterFn = [=](Value value, unsigned memorySpace,
const BufferizationOptions &options) {
auto tensorType = value.getType().cast<TensorType>();
if (unknownTypeConversionOption ==
BufferizationOptions::LayoutMapOption::IdentityLayoutMap)
return bufferization::getMemRefTypeWithStaticIdentityLayout(
tensorType, memorySpace);
assert(
unknownTypeConversionOption ==
BufferizationOptions::LayoutMapOption::FullyDynamicLayoutMap &&
"invalid layout map option");
return bufferization::getMemRefTypeWithFullyDynamicLayout(tensorType,
memorySpace);
};
// Configure op filter.
OpFilter::Entry::FilterFn filterFn = [&](Operation *op) {
// Filter may be specified via options.
if (this->dialectFilter.hasValue())
return llvm::is_contained(this->dialectFilter,
op->getDialect()->getNamespace());
// No filter specified: All other ops are allowed.
return true;
};
opt.opFilter.allowOperation(filterFn);
} else {
opt = *options;
}
ModuleOp moduleOp = getOperation();
if (opt.bufferizeFunctionBoundaries) {
if (failed(runOneShotModuleBufferize(moduleOp, opt))) {
signalPassFailure();
return;
}
} else {
if (failed(runOneShotBufferize(moduleOp, opt))) {
signalPassFailure();
return;
}
}
if (opt.testAnalysisOnly)
return;
OpPassManager cleanupPipeline("builtin.module");
cleanupPipeline.addPass(createCanonicalizerPass());
cleanupPipeline.addPass(createCSEPass());
cleanupPipeline.addPass(createLoopInvariantCodeMotionPass());
(void)runPipeline(cleanupPipeline, moduleOp);
}
private:
llvm::Optional<OneShotBufferizationOptions> options;
};
} // namespace
namespace {
struct BufferizationBufferizePass
: public BufferizationBufferizeBase<BufferizationBufferizePass> {
void runOnOperation() override {
BufferizationOptions options = getPartialBufferizationOptions();
options.opFilter.allowDialect<BufferizationDialect>();
if (failed(bufferizeOp(getOperation(), options)))
signalPassFailure();
}
void getDependentDialects(DialectRegistry &registry) const override {
registry
.insert<bufferization::BufferizationDialect, memref::MemRefDialect>();
}
};
} // namespace
std::unique_ptr<Pass> mlir::bufferization::createBufferizationBufferizePass() {
return std::make_unique<BufferizationBufferizePass>();
}
std::unique_ptr<Pass> mlir::bufferization::createOneShotBufferizePass() {
return std::make_unique<OneShotBufferizePass>();
}
std::unique_ptr<Pass> mlir::bufferization::createOneShotBufferizePass(
const OneShotBufferizationOptions &options) {
return std::make_unique<OneShotBufferizePass>(options);
}
std::unique_ptr<OperationPass<func::FuncOp>>
mlir::bufferization::createFinalizingBufferizePass() {
return std::make_unique<FinalizingBufferizePass>();
}
//===----------------------------------------------------------------------===//
// BufferizableOpInterface-based Bufferization
//===----------------------------------------------------------------------===//
static bool isaTensor(Type t) { return t.isa<TensorType>(); }
/// Return true if the given op has a tensor result or a tensor operand.
static bool hasTensorSemantics(Operation *op) {
if (auto funcOp = dyn_cast<FunctionOpInterface>(op)) {
bool hasTensorArg = any_of(funcOp.getArgumentTypes(), isaTensor);
bool hasTensorResult = any_of(funcOp.getResultTypes(), isaTensor);
return hasTensorArg || hasTensorResult;
}
bool hasTensorResult = any_of(op->getResultTypes(), isaTensor);
bool hasTensorOperand = any_of(op->getOperandTypes(), isaTensor);
return hasTensorResult || hasTensorOperand;
}
namespace {
/// A rewriter that keeps track of extra information during bufferization.
class BufferizationRewriter : public IRRewriter {
public:
BufferizationRewriter(MLIRContext *ctx, DenseSet<Operation *> &erasedOps,
DenseSet<Operation *> &toMemrefOps,
SmallVector<Operation *> &worklist,
const BufferizationOptions &options,
const OpFilter *opFilter)
: IRRewriter(ctx), erasedOps(erasedOps), toMemrefOps(toMemrefOps),
worklist(worklist), analysisState(options), opFilter(opFilter) {}
protected:
void notifyOperationRemoved(Operation *op) override {
IRRewriter::notifyOperationRemoved(op);
erasedOps.insert(op);
// Erase if present.
toMemrefOps.erase(op);
}
void notifyOperationInserted(Operation *op) override {
IRRewriter::notifyOperationInserted(op);
erasedOps.erase(op);
// Keep track of to_memref ops.
if (isa<ToMemrefOp>(op)) {
toMemrefOps.insert(op);
return;
}
// Skip to_tensor ops.
if (isa<ToTensorOp>(op))
return;
// Skip non-tensor ops.
if (!hasTensorSemantics(op))
return;
// Skip ops that are not allowed to be bufferized.
auto const &options = analysisState.getOptions();
if (!options.isOpAllowed(op) || (opFilter && !opFilter->isOpAllowed(op)))
return;
#ifndef NDEBUG
// Read-only tensor ops may be created during bufferization. Ops that are
// writing should not be created because such ops were never analyzed.
// Bufferizing such ops could introduce a RaW conflict.
for (OpOperand &operand : op->getOpOperands())
if (operand.get().getType().isa<TensorType>())
assert(!analysisState.bufferizesToMemoryWrite(operand) &&
"creating tensor ops that bufferize to a memory write is not "
"allowed during bufferization");
#endif // NDEBUG
// Add op to worklist.
worklist.push_back(op);
}
private:
/// A set of all erased ops.
DenseSet<Operation *> &erasedOps;
/// A set of all to_memref ops.
DenseSet<Operation *> &toMemrefOps;
/// The worklist of ops to be bufferized.
SmallVector<Operation *> &worklist;
/// The analysis state. Used for debug assertions and access to the
/// bufferization options.
const AnalysisState analysisState;
/// An extra op filter for bufferization.
const OpFilter *opFilter;
};
} // namespace
LogicalResult bufferization::bufferizeOp(Operation *op,
const BufferizationOptions &options,
bool copyBeforeWrite,
const OpFilter *opFilter) {
if (copyBeforeWrite) {
AnalysisState state(options);
if (failed(insertTensorCopies(op, state)))
return failure();
}
// Keep track of to_memref ops.
DenseSet<Operation *> toMemrefOps;
op->walk([&](ToMemrefOp toMemrefOp) { toMemrefOps.insert(toMemrefOp); });
// Gather all bufferizable ops in top-to-bottom order.
//
// We should ideally know the exact memref type of all operands when
// bufferizing an op. (This is the case when bufferizing top-to-bottom.)
// Otherwise, we have to use a memref type with a fully dynamic layout map to
// avoid copies. We are currently missing patterns for layout maps to
// canonicalize away (or canonicalize to more precise layouts).
//
// FuncOps must be bufferized before their bodies, so add them to the worklist
// first.
SmallVector<Operation *> worklist;
op->walk([&](func::FuncOp funcOp) {
if (hasTensorSemantics(funcOp))
worklist.push_back(funcOp);
});
op->walk<WalkOrder::PostOrder>([&](Operation *op) {
if (hasTensorSemantics(op) && !isa<func::FuncOp>(op))
worklist.push_back(op);
});
// Keep track of all erased ops.
DenseSet<Operation *> erasedOps;
// Bufferize all ops.
BufferizationRewriter rewriter(op->getContext(), erasedOps, toMemrefOps,
worklist, options, opFilter);
for (unsigned i = 0; i < worklist.size(); ++i) {
Operation *op = worklist[i];
// Skip ops that were erased.
if (erasedOps.contains(op))
continue;
// Skip ops that are not bufferizable or not allowed.
auto bufferizableOp = options.dynCastBufferizableOp(op);
if (!bufferizableOp)
continue;
if (opFilter && !opFilter->isOpAllowed(op))
continue;
// Skip ops that no longer have tensor semantics.
if (!hasTensorSemantics(op))
continue;
// Bufferize the op.
rewriter.setInsertionPoint(op);
if (failed(bufferizableOp.bufferize(rewriter, options)))
return op->emitError("failed to bufferize op");
}
// Fold all to_memref(to_tensor(x)) pairs.
for (Operation *op : toMemrefOps) {
rewriter.setInsertionPoint(op);
(void)bufferization::foldToMemrefToTensorPair(rewriter,
cast<ToMemrefOp>(op));
}
/// Check the result of bufferization. Return an error if an op was not
/// bufferized, unless partial bufferization is allowed.
if (options.allowUnknownOps)
return success();
for (Operation *op : worklist) {
// Skip ops that are entirely gone.
if (erasedOps.contains(op))
continue;
// Ops that no longer have tensor semantics (because they were updated
// in-place) are allowed.
if (!hasTensorSemantics(op))
continue;
// Continue ops that are not allowed.
if (!options.isOpAllowed(op))
continue;
if (opFilter && !opFilter->isOpAllowed(op))
continue;
// Ops without any uses and no side effects will fold away.
if (op->getUses().empty() && MemoryEffectOpInterface::hasNoEffect(op))
continue;
// ToTensorOps/ToMemrefOps are allowed in the output.
if (isa<ToTensorOp, ToMemrefOp>(op))
continue;
return op->emitError("op was not bufferized");
}
return success();
}
BufferizationOptions bufferization::getPartialBufferizationOptions() {
BufferizationOptions options;
options.allowUnknownOps = true;
options.createDeallocs = false;
options.enforceAliasingInvariants = false;
options.unknownTypeConverterFn = [](Value value, unsigned memorySpace,
const BufferizationOptions &options) {
return getMemRefTypeWithStaticIdentityLayout(
value.getType().cast<TensorType>(), memorySpace);
};
options.opFilter.allowDialect<BufferizationDialect>();
return options;
}