llvm-project/mlir/lib/Dialect/SparseTensor/Transforms/SparseTensorConversion.cpp

436 lines
16 KiB
C++

//===- SparseTensorLowering.cpp - Sparse tensor primitives conversion -----===//
//
// 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
//
//===----------------------------------------------------------------------===//
//
// Convert sparse tensor primitives to calls into a runtime support library.
// Note that this is a current implementation choice to keep the conversion
// simple. In principle, these primitives could also be converted to actual
// elaborate IR code that implements the primitives on the selected sparse
// tensor storage schemes.
//
//===----------------------------------------------------------------------===//
#include "mlir/Dialect/LLVMIR/LLVMTypes.h"
#include "mlir/Dialect/MemRef/IR/MemRef.h"
#include "mlir/Dialect/SparseTensor/IR/SparseTensor.h"
#include "mlir/Dialect/SparseTensor/Transforms/Passes.h"
#include "mlir/Dialect/StandardOps/IR/Ops.h"
#include "mlir/Dialect/Tensor/IR/Tensor.h"
#include "mlir/Transforms/DialectConversion.h"
using namespace mlir;
using namespace mlir::sparse_tensor;
namespace {
//===----------------------------------------------------------------------===//
// Helper methods.
//===----------------------------------------------------------------------===//
/// Returns internal type encoding for primary storage. Keep these
/// values consistent with the sparse runtime support library.
static unsigned getPrimaryTypeEncoding(Type tp) {
if (tp.isF64())
return 1;
if (tp.isF32())
return 2;
if (tp.isInteger(64))
return 3;
if (tp.isInteger(32))
return 4;
if (tp.isInteger(16))
return 5;
if (tp.isInteger(8))
return 6;
return 0;
}
/// Returns internal type encoding for overhead storage. Keep these
/// values consistent with the sparse runtime support library.
static unsigned getOverheadTypeEncoding(unsigned width) {
switch (width) {
default:
return 1;
case 32:
return 2;
case 16:
return 3;
case 8:
return 4;
}
}
/// Returns internal dimension level type encoding. Keep these
/// values consistent with the sparse runtime support library.
static unsigned
getDimLevelTypeEncoding(SparseTensorEncodingAttr::DimLevelType dlt) {
switch (dlt) {
case SparseTensorEncodingAttr::DimLevelType::Dense:
return 0;
case SparseTensorEncodingAttr::DimLevelType::Compressed:
return 1;
case SparseTensorEncodingAttr::DimLevelType::Singleton:
return 2;
}
llvm_unreachable("Unknown SparseTensorEncodingAttr::DimLevelType");
}
/// Returns integers of given width and values as a constant tensor.
/// We cast the static shape into a dynamic shape to ensure that the
/// method signature remains uniform accross different tensor dimensions.
static Value getTensor(ConversionPatternRewriter &rewriter, unsigned width,
Location loc, ArrayRef<APInt> values) {
Type etp = rewriter.getIntegerType(width);
unsigned sz = values.size();
RankedTensorType tt1 = RankedTensorType::get({sz}, etp);
RankedTensorType tt2 = RankedTensorType::get({ShapedType::kDynamicSize}, etp);
auto elts =
rewriter.create<ConstantOp>(loc, DenseElementsAttr::get(tt1, values));
return rewriter.create<tensor::CastOp>(loc, tt2, elts);
}
/// Returns function reference (first hit also inserts into module).
static FlatSymbolRefAttr getFunc(Operation *op, StringRef name, Type result,
ValueRange operands) {
MLIRContext *context = op->getContext();
auto module = op->getParentOfType<ModuleOp>();
auto func = module.lookupSymbol<FuncOp>(name);
if (!func) {
OpBuilder moduleBuilder(module.getBodyRegion());
moduleBuilder
.create<FuncOp>(op->getLoc(), name,
FunctionType::get(context, operands.getTypes(), result))
.setPrivate();
}
return SymbolRefAttr::get(context, name);
}
/// Generates a call into the "swiss army knife" method of the sparse runtime
/// support library for materializing sparse tensors into the computation.
static void genNewCall(ConversionPatternRewriter &rewriter, Operation *op,
SparseTensorEncodingAttr &enc, uint32_t action,
Value ptr) {
Location loc = op->getLoc();
ShapedType resType = op->getResult(0).getType().cast<ShapedType>();
SmallVector<Value, 8> params;
// Sparsity annotations in tensor constant form.
SmallVector<APInt, 4> attrs;
unsigned sz = enc.getDimLevelType().size();
for (unsigned i = 0; i < sz; i++)
attrs.push_back(
APInt(8, getDimLevelTypeEncoding(enc.getDimLevelType()[i])));
params.push_back(getTensor(rewriter, 8, loc, attrs));
// Dimension sizes array of the enveloping *dense* tensor. Useful for either
// verification of external data, or for construction of internal data.
auto shape = resType.getShape();
SmallVector<APInt, 4> sizes;
for (unsigned i = 0; i < sz; i++) {
uint64_t s = shape[i] == ShapedType::kDynamicSize ? 0 : shape[i];
sizes.push_back(APInt(64, s));
}
params.push_back(getTensor(rewriter, 64, loc, sizes));
// Dimension order permutation array. This is the "identity" permutation by
// default, or otherwise the "reverse" permutation of a given ordering, so
// that indices can be mapped quickly to the right position.
SmallVector<APInt, 4> perm(sz);
AffineMap p = enc.getDimOrdering();
if (p) {
assert(p.isPermutation() && p.getNumResults() == sz);
for (unsigned i = 0; i < sz; i++)
perm[p.getDimPosition(i)] = APInt(64, i);
} else {
for (unsigned i = 0; i < sz; i++)
perm[i] = APInt(64, i);
}
params.push_back(getTensor(rewriter, 64, loc, perm));
// Secondary and primary types encoding.
unsigned secPtr = getOverheadTypeEncoding(enc.getPointerBitWidth());
unsigned secInd = getOverheadTypeEncoding(enc.getIndexBitWidth());
unsigned primary = getPrimaryTypeEncoding(resType.getElementType());
assert(primary);
params.push_back(
rewriter.create<ConstantOp>(loc, rewriter.getI64IntegerAttr(secPtr)));
params.push_back(
rewriter.create<ConstantOp>(loc, rewriter.getI64IntegerAttr(secInd)));
params.push_back(
rewriter.create<ConstantOp>(loc, rewriter.getI64IntegerAttr(primary)));
// User action and pointer.
params.push_back(
rewriter.create<ConstantOp>(loc, rewriter.getI32IntegerAttr(action)));
params.push_back(ptr);
// Generate the call to create new tensor.
Type ptrType =
LLVM::LLVMPointerType::get(IntegerType::get(op->getContext(), 8));
StringRef name = "newSparseTensor";
rewriter.replaceOpWithNewOp<CallOp>(
op, ptrType, getFunc(op, name, ptrType, params), params);
}
/// Generates a call that exposes the data pointer as a void pointer.
// TODO: probing the data pointer directly is a bit raw; we should replace
// this with proper memref util calls once they become available.
static bool genPtrCall(ConversionPatternRewriter &rewriter, Operation *op,
Value val, Value &ptr) {
Location loc = op->getLoc();
ShapedType sType = op->getResult(0).getType().cast<ShapedType>();
Type eltType = sType.getElementType();
// Specialize name for the data type. Even though the final buffferized
// version only operates on pointers, different names are required to
// ensure type correctness for all intermediate states.
StringRef name;
if (eltType.isF64())
name = "getPtrF64";
else if (eltType.isF32())
name = "getPtrF32";
else if (eltType.isInteger(64))
name = "getPtrI64";
else if (eltType.isInteger(32))
name = "getPtrI32";
else if (eltType.isInteger(16))
name = "getPtrI16";
else if (eltType.isInteger(8))
name = "getPtrI8";
else
return false;
auto memRefTp = MemRefType::get(sType.getShape(), eltType);
auto unrankedTp = UnrankedMemRefType::get(eltType, 0);
Value c = rewriter.create<memref::BufferCastOp>(loc, memRefTp, val);
Value d = rewriter.create<memref::CastOp>(loc, unrankedTp, c);
Type ptrType =
LLVM::LLVMPointerType::get(IntegerType::get(op->getContext(), 8));
auto call =
rewriter.create<CallOp>(loc, ptrType, getFunc(op, name, ptrType, d), d);
ptr = call.getResult(0);
return true;
}
//===----------------------------------------------------------------------===//
// Conversion rules.
//===----------------------------------------------------------------------===//
/// Sparse conversion rule for returns.
class SparseReturnConverter : public OpConversionPattern<ReturnOp> {
public:
using OpConversionPattern::OpConversionPattern;
LogicalResult
matchAndRewrite(ReturnOp op, ArrayRef<Value> operands,
ConversionPatternRewriter &rewriter) const override {
rewriter.replaceOpWithNewOp<ReturnOp>(op, operands);
return success();
}
};
/// Sparse conversion rule for dimension accesses.
class SparseTensorToDimSizeConverter
: public OpConversionPattern<tensor::DimOp> {
public:
using OpConversionPattern::OpConversionPattern;
LogicalResult
matchAndRewrite(tensor::DimOp op, ArrayRef<Value> operands,
ConversionPatternRewriter &rewriter) const override {
Type resType = op.getType();
auto enc = getSparseTensorEncoding(op.source().getType());
if (!enc)
return failure();
// Permute the dim index.
Optional<int64_t> index = op.getConstantIndex();
if (!index.hasValue())
return failure();
int64_t idx = index.getValue();
AffineMap p = enc.getDimOrdering();
if (p) {
assert(p.isPermutation());
for (unsigned i = 0, sz = p.getNumResults(); i < sz; i++) {
if (p.getDimPosition(i) == idx) {
idx = i;
break;
}
}
}
// Generate the call.
StringRef name = "sparseDimSize";
SmallVector<Value, 2> params;
params.push_back(operands[0]);
params.push_back(
rewriter.create<ConstantOp>(op.getLoc(), rewriter.getIndexAttr(idx)));
rewriter.replaceOpWithNewOp<CallOp>(
op, resType, getFunc(op, name, resType, params), params);
return success();
}
};
/// Sparse conversion rule for the new operator.
class SparseTensorNewConverter : public OpConversionPattern<NewOp> {
using OpConversionPattern::OpConversionPattern;
LogicalResult
matchAndRewrite(NewOp op, ArrayRef<Value> operands,
ConversionPatternRewriter &rewriter) const override {
Type resType = op.getType();
auto enc = getSparseTensorEncoding(resType);
if (!enc)
return failure();
genNewCall(rewriter, op, enc, 0, operands[0]);
return success();
}
};
/// Sparse conversion rule for the convert operator.
class SparseTensorConvertConverter : public OpConversionPattern<ConvertOp> {
using OpConversionPattern::OpConversionPattern;
LogicalResult
matchAndRewrite(ConvertOp op, ArrayRef<Value> operands,
ConversionPatternRewriter &rewriter) const override {
Type resType = op.getType();
auto encDst = getSparseTensorEncoding(resType);
auto encSrc = getSparseTensorEncoding(op.source().getType());
// TODO: implement sparse => sparse
// and sparse => dense
if (!encDst || encSrc)
return failure();
// This is a dense => sparse conversion.
Value ptr;
if (!genPtrCall(rewriter, op, operands[0], ptr))
return failure();
genNewCall(rewriter, op, encDst, 1, ptr);
return success();
}
};
/// Sparse conversion rule for pointer accesses.
class SparseTensorToPointersConverter
: public OpConversionPattern<ToPointersOp> {
public:
using OpConversionPattern::OpConversionPattern;
LogicalResult
matchAndRewrite(ToPointersOp op, ArrayRef<Value> operands,
ConversionPatternRewriter &rewriter) const override {
Type resType = op.getType();
Type eltType = resType.cast<ShapedType>().getElementType();
StringRef name;
if (eltType.isIndex())
name = "sparsePointers";
else if (eltType.isInteger(64))
name = "sparsePointers64";
else if (eltType.isInteger(32))
name = "sparsePointers32";
else if (eltType.isInteger(16))
name = "sparsePointers16";
else if (eltType.isInteger(8))
name = "sparsePointers8";
else
return failure();
rewriter.replaceOpWithNewOp<CallOp>(
op, resType, getFunc(op, name, resType, operands), operands);
return success();
}
};
/// Sparse conversion rule for index accesses.
class SparseTensorToIndicesConverter : public OpConversionPattern<ToIndicesOp> {
public:
using OpConversionPattern::OpConversionPattern;
LogicalResult
matchAndRewrite(ToIndicesOp op, ArrayRef<Value> operands,
ConversionPatternRewriter &rewriter) const override {
Type resType = op.getType();
Type eltType = resType.cast<ShapedType>().getElementType();
StringRef name;
if (eltType.isIndex())
name = "sparseIndices";
else if (eltType.isInteger(64))
name = "sparseIndices64";
else if (eltType.isInteger(32))
name = "sparseIndices32";
else if (eltType.isInteger(16))
name = "sparseIndices16";
else if (eltType.isInteger(8))
name = "sparseIndices8";
else
return failure();
rewriter.replaceOpWithNewOp<CallOp>(
op, resType, getFunc(op, name, resType, operands), operands);
return success();
}
};
/// Sparse conversion rule for value accesses.
class SparseTensorToValuesConverter : public OpConversionPattern<ToValuesOp> {
public:
using OpConversionPattern::OpConversionPattern;
LogicalResult
matchAndRewrite(ToValuesOp op, ArrayRef<Value> operands,
ConversionPatternRewriter &rewriter) const override {
Type resType = op.getType();
Type eltType = resType.cast<ShapedType>().getElementType();
StringRef name;
if (eltType.isF64())
name = "sparseValuesF64";
else if (eltType.isF32())
name = "sparseValuesF32";
else if (eltType.isInteger(64))
name = "sparseValuesI64";
else if (eltType.isInteger(32))
name = "sparseValuesI32";
else if (eltType.isInteger(16))
name = "sparseValuesI16";
else if (eltType.isInteger(8))
name = "sparseValuesI8";
else
return failure();
rewriter.replaceOpWithNewOp<CallOp>(
op, resType, getFunc(op, name, resType, operands), operands);
return success();
}
};
/// Sparse conversion rule for tensor reconstruction.
class SparseTensorToTensorConverter : public OpConversionPattern<ToTensorOp> {
public:
using OpConversionPattern::OpConversionPattern;
LogicalResult
// Simply fold the operator into the pointer to the sparse storage scheme.
matchAndRewrite(ToTensorOp op, ArrayRef<Value> operands,
ConversionPatternRewriter &rewriter) const override {
// Check that all arguments of the tensor reconstruction operators are calls
// into the support library that query exactly the same opaque pointer.
Value ptr;
for (Value op : operands) {
if (auto call = op.getDefiningOp<CallOp>()) {
Value arg = call.getOperand(0);
if (!arg.getType().isa<LLVM::LLVMPointerType>())
return failure();
if (!ptr)
ptr = arg;
else if (arg != ptr)
return failure();
}
}
// If a single opaque pointer is found, perform the folding.
if (!ptr)
return failure();
rewriter.replaceOp(op, ptr);
return success();
}
};
} // namespace
//===----------------------------------------------------------------------===//
// Public method for populating conversion rules.
//===----------------------------------------------------------------------===//
/// Populates the given patterns list with conversion rules required for
/// the sparsification of linear algebra operations.
void mlir::populateSparseTensorConversionPatterns(TypeConverter &typeConverter,
RewritePatternSet &patterns) {
patterns.add<SparseReturnConverter, SparseTensorToDimSizeConverter,
SparseTensorNewConverter, SparseTensorConvertConverter,
SparseTensorToPointersConverter, SparseTensorToIndicesConverter,
SparseTensorToValuesConverter, SparseTensorToTensorConverter>(
typeConverter, patterns.getContext());
}