Files
clang-p2996/mlir/lib/Conversion/LLVMCommon/MemRefBuilder.cpp
Alex Zinenko b5d847b1b9 [mlir] factor out common parts of the converstion to the LLVM dialect
"Standard-to-LLVM" conversion is one of the oldest passes in existence. It has
become quite large due to the size of the Standard dialect itself, which is
being split into multiple smaller dialects. Furthermore, several conversion
features are useful for any dialect that is being converted to the LLVM
dialect, which, without this refactoring, creates a dependency from those
conversions to the "standard-to-llvm" one.

Put several of the reusable utilities from this conversion to a separate
library, namely:
- type converter from builtin to LLVM dialect types;
- utility for building and accessing values of LLVM structure type;
- utility for building and accessing values that represent memref in the LLVM
  dialect;
- lowering options applicable everywhere.

Additionally, remove the type wrapping/unwrapping notion from the type
converter that is no longer relevant since LLVM types has been reimplemented as
first-class MLIR types.

Reviewed By: pifon2a

Differential Revision: https://reviews.llvm.org/D105534
2021-07-07 10:51:08 +02:00

526 lines
23 KiB
C++

//===- MemRefBuilder.cpp - Helper for LLVM MemRef equivalents -------------===//
//
// 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 "mlir/Conversion/LLVMCommon/MemRefBuilder.h"
#include "MemRefDescriptor.h"
#include "mlir/Conversion/LLVMCommon/TypeConverter.h"
#include "mlir/Dialect/LLVMIR/LLVMDialect.h"
#include "mlir/IR/Builders.h"
#include "mlir/Support/MathExtras.h"
using namespace mlir;
//===----------------------------------------------------------------------===//
// MemRefDescriptor implementation
//===----------------------------------------------------------------------===//
/// Construct a helper for the given descriptor value.
MemRefDescriptor::MemRefDescriptor(Value descriptor)
: StructBuilder(descriptor) {
assert(value != nullptr && "value cannot be null");
indexType = value.getType()
.cast<LLVM::LLVMStructType>()
.getBody()[kOffsetPosInMemRefDescriptor];
}
/// Builds IR creating an `undef` value of the descriptor type.
MemRefDescriptor MemRefDescriptor::undef(OpBuilder &builder, Location loc,
Type descriptorType) {
Value descriptor = builder.create<LLVM::UndefOp>(loc, descriptorType);
return MemRefDescriptor(descriptor);
}
/// Builds IR creating a MemRef descriptor that represents `type` and
/// populates it with static shape and stride information extracted from the
/// type.
MemRefDescriptor
MemRefDescriptor::fromStaticShape(OpBuilder &builder, Location loc,
LLVMTypeConverter &typeConverter,
MemRefType type, Value memory) {
assert(type.hasStaticShape() && "unexpected dynamic shape");
// Extract all strides and offsets and verify they are static.
int64_t offset;
SmallVector<int64_t, 4> strides;
auto result = getStridesAndOffset(type, strides, offset);
(void)result;
assert(succeeded(result) && "unexpected failure in stride computation");
assert(!MemRefType::isDynamicStrideOrOffset(offset) &&
"expected static offset");
assert(!llvm::any_of(strides, [](int64_t stride) {
return MemRefType::isDynamicStrideOrOffset(stride);
}) && "expected static strides");
auto convertedType = typeConverter.convertType(type);
assert(convertedType && "unexpected failure in memref type conversion");
auto descr = MemRefDescriptor::undef(builder, loc, convertedType);
descr.setAllocatedPtr(builder, loc, memory);
descr.setAlignedPtr(builder, loc, memory);
descr.setConstantOffset(builder, loc, offset);
// Fill in sizes and strides
for (unsigned i = 0, e = type.getRank(); i != e; ++i) {
descr.setConstantSize(builder, loc, i, type.getDimSize(i));
descr.setConstantStride(builder, loc, i, strides[i]);
}
return descr;
}
/// Builds IR extracting the allocated pointer from the descriptor.
Value MemRefDescriptor::allocatedPtr(OpBuilder &builder, Location loc) {
return extractPtr(builder, loc, kAllocatedPtrPosInMemRefDescriptor);
}
/// Builds IR inserting the allocated pointer into the descriptor.
void MemRefDescriptor::setAllocatedPtr(OpBuilder &builder, Location loc,
Value ptr) {
setPtr(builder, loc, kAllocatedPtrPosInMemRefDescriptor, ptr);
}
/// Builds IR extracting the aligned pointer from the descriptor.
Value MemRefDescriptor::alignedPtr(OpBuilder &builder, Location loc) {
return extractPtr(builder, loc, kAlignedPtrPosInMemRefDescriptor);
}
/// Builds IR inserting the aligned pointer into the descriptor.
void MemRefDescriptor::setAlignedPtr(OpBuilder &builder, Location loc,
Value ptr) {
setPtr(builder, loc, kAlignedPtrPosInMemRefDescriptor, ptr);
}
// Creates a constant Op producing a value of `resultType` from an index-typed
// integer attribute.
static Value createIndexAttrConstant(OpBuilder &builder, Location loc,
Type resultType, int64_t value) {
return builder.create<LLVM::ConstantOp>(
loc, resultType, builder.getIntegerAttr(builder.getIndexType(), value));
}
/// Builds IR extracting the offset from the descriptor.
Value MemRefDescriptor::offset(OpBuilder &builder, Location loc) {
return builder.create<LLVM::ExtractValueOp>(
loc, indexType, value,
builder.getI64ArrayAttr(kOffsetPosInMemRefDescriptor));
}
/// Builds IR inserting the offset into the descriptor.
void MemRefDescriptor::setOffset(OpBuilder &builder, Location loc,
Value offset) {
value = builder.create<LLVM::InsertValueOp>(
loc, structType, value, offset,
builder.getI64ArrayAttr(kOffsetPosInMemRefDescriptor));
}
/// Builds IR inserting the offset into the descriptor.
void MemRefDescriptor::setConstantOffset(OpBuilder &builder, Location loc,
uint64_t offset) {
setOffset(builder, loc,
createIndexAttrConstant(builder, loc, indexType, offset));
}
/// Builds IR extracting the pos-th size from the descriptor.
Value MemRefDescriptor::size(OpBuilder &builder, Location loc, unsigned pos) {
return builder.create<LLVM::ExtractValueOp>(
loc, indexType, value,
builder.getI64ArrayAttr({kSizePosInMemRefDescriptor, pos}));
}
Value MemRefDescriptor::size(OpBuilder &builder, Location loc, Value pos,
int64_t rank) {
auto indexPtrTy = LLVM::LLVMPointerType::get(indexType);
auto arrayTy = LLVM::LLVMArrayType::get(indexType, rank);
auto arrayPtrTy = LLVM::LLVMPointerType::get(arrayTy);
// Copy size values to stack-allocated memory.
auto zero = createIndexAttrConstant(builder, loc, indexType, 0);
auto one = createIndexAttrConstant(builder, loc, indexType, 1);
auto sizes = builder.create<LLVM::ExtractValueOp>(
loc, arrayTy, value,
builder.getI64ArrayAttr({kSizePosInMemRefDescriptor}));
auto sizesPtr =
builder.create<LLVM::AllocaOp>(loc, arrayPtrTy, one, /*alignment=*/0);
builder.create<LLVM::StoreOp>(loc, sizes, sizesPtr);
// Load an return size value of interest.
auto resultPtr = builder.create<LLVM::GEPOp>(loc, indexPtrTy, sizesPtr,
ValueRange({zero, pos}));
return builder.create<LLVM::LoadOp>(loc, resultPtr);
}
/// Builds IR inserting the pos-th size into the descriptor
void MemRefDescriptor::setSize(OpBuilder &builder, Location loc, unsigned pos,
Value size) {
value = builder.create<LLVM::InsertValueOp>(
loc, structType, value, size,
builder.getI64ArrayAttr({kSizePosInMemRefDescriptor, pos}));
}
void MemRefDescriptor::setConstantSize(OpBuilder &builder, Location loc,
unsigned pos, uint64_t size) {
setSize(builder, loc, pos,
createIndexAttrConstant(builder, loc, indexType, size));
}
/// Builds IR extracting the pos-th stride from the descriptor.
Value MemRefDescriptor::stride(OpBuilder &builder, Location loc, unsigned pos) {
return builder.create<LLVM::ExtractValueOp>(
loc, indexType, value,
builder.getI64ArrayAttr({kStridePosInMemRefDescriptor, pos}));
}
/// Builds IR inserting the pos-th stride into the descriptor
void MemRefDescriptor::setStride(OpBuilder &builder, Location loc, unsigned pos,
Value stride) {
value = builder.create<LLVM::InsertValueOp>(
loc, structType, value, stride,
builder.getI64ArrayAttr({kStridePosInMemRefDescriptor, pos}));
}
void MemRefDescriptor::setConstantStride(OpBuilder &builder, Location loc,
unsigned pos, uint64_t stride) {
setStride(builder, loc, pos,
createIndexAttrConstant(builder, loc, indexType, stride));
}
LLVM::LLVMPointerType MemRefDescriptor::getElementPtrType() {
return value.getType()
.cast<LLVM::LLVMStructType>()
.getBody()[kAlignedPtrPosInMemRefDescriptor]
.cast<LLVM::LLVMPointerType>();
}
/// Creates a MemRef descriptor structure from a list of individual values
/// composing that descriptor, in the following order:
/// - allocated pointer;
/// - aligned pointer;
/// - offset;
/// - <rank> sizes;
/// - <rank> shapes;
/// where <rank> is the MemRef rank as provided in `type`.
Value MemRefDescriptor::pack(OpBuilder &builder, Location loc,
LLVMTypeConverter &converter, MemRefType type,
ValueRange values) {
Type llvmType = converter.convertType(type);
auto d = MemRefDescriptor::undef(builder, loc, llvmType);
d.setAllocatedPtr(builder, loc, values[kAllocatedPtrPosInMemRefDescriptor]);
d.setAlignedPtr(builder, loc, values[kAlignedPtrPosInMemRefDescriptor]);
d.setOffset(builder, loc, values[kOffsetPosInMemRefDescriptor]);
int64_t rank = type.getRank();
for (unsigned i = 0; i < rank; ++i) {
d.setSize(builder, loc, i, values[kSizePosInMemRefDescriptor + i]);
d.setStride(builder, loc, i, values[kSizePosInMemRefDescriptor + rank + i]);
}
return d;
}
/// Builds IR extracting individual elements of a MemRef descriptor structure
/// and returning them as `results` list.
void MemRefDescriptor::unpack(OpBuilder &builder, Location loc, Value packed,
MemRefType type,
SmallVectorImpl<Value> &results) {
int64_t rank = type.getRank();
results.reserve(results.size() + getNumUnpackedValues(type));
MemRefDescriptor d(packed);
results.push_back(d.allocatedPtr(builder, loc));
results.push_back(d.alignedPtr(builder, loc));
results.push_back(d.offset(builder, loc));
for (int64_t i = 0; i < rank; ++i)
results.push_back(d.size(builder, loc, i));
for (int64_t i = 0; i < rank; ++i)
results.push_back(d.stride(builder, loc, i));
}
/// Returns the number of non-aggregate values that would be produced by
/// `unpack`.
unsigned MemRefDescriptor::getNumUnpackedValues(MemRefType type) {
// Two pointers, offset, <rank> sizes, <rank> shapes.
return 3 + 2 * type.getRank();
}
//===----------------------------------------------------------------------===//
// MemRefDescriptorView implementation.
//===----------------------------------------------------------------------===//
MemRefDescriptorView::MemRefDescriptorView(ValueRange range)
: rank((range.size() - kSizePosInMemRefDescriptor) / 2), elements(range) {}
Value MemRefDescriptorView::allocatedPtr() {
return elements[kAllocatedPtrPosInMemRefDescriptor];
}
Value MemRefDescriptorView::alignedPtr() {
return elements[kAlignedPtrPosInMemRefDescriptor];
}
Value MemRefDescriptorView::offset() {
return elements[kOffsetPosInMemRefDescriptor];
}
Value MemRefDescriptorView::size(unsigned pos) {
return elements[kSizePosInMemRefDescriptor + pos];
}
Value MemRefDescriptorView::stride(unsigned pos) {
return elements[kSizePosInMemRefDescriptor + rank + pos];
}
//===----------------------------------------------------------------------===//
// UnrankedMemRefDescriptor implementation
//===----------------------------------------------------------------------===//
/// Construct a helper for the given descriptor value.
UnrankedMemRefDescriptor::UnrankedMemRefDescriptor(Value descriptor)
: StructBuilder(descriptor) {}
/// Builds IR creating an `undef` value of the descriptor type.
UnrankedMemRefDescriptor UnrankedMemRefDescriptor::undef(OpBuilder &builder,
Location loc,
Type descriptorType) {
Value descriptor = builder.create<LLVM::UndefOp>(loc, descriptorType);
return UnrankedMemRefDescriptor(descriptor);
}
Value UnrankedMemRefDescriptor::rank(OpBuilder &builder, Location loc) {
return extractPtr(builder, loc, kRankInUnrankedMemRefDescriptor);
}
void UnrankedMemRefDescriptor::setRank(OpBuilder &builder, Location loc,
Value v) {
setPtr(builder, loc, kRankInUnrankedMemRefDescriptor, v);
}
Value UnrankedMemRefDescriptor::memRefDescPtr(OpBuilder &builder,
Location loc) {
return extractPtr(builder, loc, kPtrInUnrankedMemRefDescriptor);
}
void UnrankedMemRefDescriptor::setMemRefDescPtr(OpBuilder &builder,
Location loc, Value v) {
setPtr(builder, loc, kPtrInUnrankedMemRefDescriptor, v);
}
/// Builds IR populating an unranked MemRef descriptor structure from a list
/// of individual constituent values in the following order:
/// - rank of the memref;
/// - pointer to the memref descriptor.
Value UnrankedMemRefDescriptor::pack(OpBuilder &builder, Location loc,
LLVMTypeConverter &converter,
UnrankedMemRefType type,
ValueRange values) {
Type llvmType = converter.convertType(type);
auto d = UnrankedMemRefDescriptor::undef(builder, loc, llvmType);
d.setRank(builder, loc, values[kRankInUnrankedMemRefDescriptor]);
d.setMemRefDescPtr(builder, loc, values[kPtrInUnrankedMemRefDescriptor]);
return d;
}
/// Builds IR extracting individual elements that compose an unranked memref
/// descriptor and returns them as `results` list.
void UnrankedMemRefDescriptor::unpack(OpBuilder &builder, Location loc,
Value packed,
SmallVectorImpl<Value> &results) {
UnrankedMemRefDescriptor d(packed);
results.reserve(results.size() + 2);
results.push_back(d.rank(builder, loc));
results.push_back(d.memRefDescPtr(builder, loc));
}
void UnrankedMemRefDescriptor::computeSizes(
OpBuilder &builder, Location loc, LLVMTypeConverter &typeConverter,
ArrayRef<UnrankedMemRefDescriptor> values, SmallVectorImpl<Value> &sizes) {
if (values.empty())
return;
// Cache the index type.
Type indexType = typeConverter.getIndexType();
// Initialize shared constants.
Value one = createIndexAttrConstant(builder, loc, indexType, 1);
Value two = createIndexAttrConstant(builder, loc, indexType, 2);
Value pointerSize = createIndexAttrConstant(
builder, loc, indexType, ceilDiv(typeConverter.getPointerBitwidth(), 8));
Value indexSize =
createIndexAttrConstant(builder, loc, indexType,
ceilDiv(typeConverter.getIndexTypeBitwidth(), 8));
sizes.reserve(sizes.size() + values.size());
for (UnrankedMemRefDescriptor desc : values) {
// Emit IR computing the memory necessary to store the descriptor. This
// assumes the descriptor to be
// { type*, type*, index, index[rank], index[rank] }
// and densely packed, so the total size is
// 2 * sizeof(pointer) + (1 + 2 * rank) * sizeof(index).
// TODO: consider including the actual size (including eventual padding due
// to data layout) into the unranked descriptor.
Value doublePointerSize =
builder.create<LLVM::MulOp>(loc, indexType, two, pointerSize);
// (1 + 2 * rank) * sizeof(index)
Value rank = desc.rank(builder, loc);
Value doubleRank = builder.create<LLVM::MulOp>(loc, indexType, two, rank);
Value doubleRankIncremented =
builder.create<LLVM::AddOp>(loc, indexType, doubleRank, one);
Value rankIndexSize = builder.create<LLVM::MulOp>(
loc, indexType, doubleRankIncremented, indexSize);
// Total allocation size.
Value allocationSize = builder.create<LLVM::AddOp>(
loc, indexType, doublePointerSize, rankIndexSize);
sizes.push_back(allocationSize);
}
}
Value UnrankedMemRefDescriptor::allocatedPtr(OpBuilder &builder, Location loc,
Value memRefDescPtr,
Type elemPtrPtrType) {
Value elementPtrPtr =
builder.create<LLVM::BitcastOp>(loc, elemPtrPtrType, memRefDescPtr);
return builder.create<LLVM::LoadOp>(loc, elementPtrPtr);
}
void UnrankedMemRefDescriptor::setAllocatedPtr(OpBuilder &builder, Location loc,
Value memRefDescPtr,
Type elemPtrPtrType,
Value allocatedPtr) {
Value elementPtrPtr =
builder.create<LLVM::BitcastOp>(loc, elemPtrPtrType, memRefDescPtr);
builder.create<LLVM::StoreOp>(loc, allocatedPtr, elementPtrPtr);
}
Value UnrankedMemRefDescriptor::alignedPtr(OpBuilder &builder, Location loc,
LLVMTypeConverter &typeConverter,
Value memRefDescPtr,
Type elemPtrPtrType) {
Value elementPtrPtr =
builder.create<LLVM::BitcastOp>(loc, elemPtrPtrType, memRefDescPtr);
Value one =
createIndexAttrConstant(builder, loc, typeConverter.getIndexType(), 1);
Value alignedGep = builder.create<LLVM::GEPOp>(
loc, elemPtrPtrType, elementPtrPtr, ValueRange({one}));
return builder.create<LLVM::LoadOp>(loc, alignedGep);
}
void UnrankedMemRefDescriptor::setAlignedPtr(OpBuilder &builder, Location loc,
LLVMTypeConverter &typeConverter,
Value memRefDescPtr,
Type elemPtrPtrType,
Value alignedPtr) {
Value elementPtrPtr =
builder.create<LLVM::BitcastOp>(loc, elemPtrPtrType, memRefDescPtr);
Value one =
createIndexAttrConstant(builder, loc, typeConverter.getIndexType(), 1);
Value alignedGep = builder.create<LLVM::GEPOp>(
loc, elemPtrPtrType, elementPtrPtr, ValueRange({one}));
builder.create<LLVM::StoreOp>(loc, alignedPtr, alignedGep);
}
Value UnrankedMemRefDescriptor::offset(OpBuilder &builder, Location loc,
LLVMTypeConverter &typeConverter,
Value memRefDescPtr,
Type elemPtrPtrType) {
Value elementPtrPtr =
builder.create<LLVM::BitcastOp>(loc, elemPtrPtrType, memRefDescPtr);
Value two =
createIndexAttrConstant(builder, loc, typeConverter.getIndexType(), 2);
Value offsetGep = builder.create<LLVM::GEPOp>(
loc, elemPtrPtrType, elementPtrPtr, ValueRange({two}));
offsetGep = builder.create<LLVM::BitcastOp>(
loc, LLVM::LLVMPointerType::get(typeConverter.getIndexType()), offsetGep);
return builder.create<LLVM::LoadOp>(loc, offsetGep);
}
void UnrankedMemRefDescriptor::setOffset(OpBuilder &builder, Location loc,
LLVMTypeConverter &typeConverter,
Value memRefDescPtr,
Type elemPtrPtrType, Value offset) {
Value elementPtrPtr =
builder.create<LLVM::BitcastOp>(loc, elemPtrPtrType, memRefDescPtr);
Value two =
createIndexAttrConstant(builder, loc, typeConverter.getIndexType(), 2);
Value offsetGep = builder.create<LLVM::GEPOp>(
loc, elemPtrPtrType, elementPtrPtr, ValueRange({two}));
offsetGep = builder.create<LLVM::BitcastOp>(
loc, LLVM::LLVMPointerType::get(typeConverter.getIndexType()), offsetGep);
builder.create<LLVM::StoreOp>(loc, offset, offsetGep);
}
Value UnrankedMemRefDescriptor::sizeBasePtr(
OpBuilder &builder, Location loc, LLVMTypeConverter &typeConverter,
Value memRefDescPtr, LLVM::LLVMPointerType elemPtrPtrType) {
Type elemPtrTy = elemPtrPtrType.getElementType();
Type indexTy = typeConverter.getIndexType();
Type structPtrTy =
LLVM::LLVMPointerType::get(LLVM::LLVMStructType::getLiteral(
indexTy.getContext(), {elemPtrTy, elemPtrTy, indexTy, indexTy}));
Value structPtr =
builder.create<LLVM::BitcastOp>(loc, structPtrTy, memRefDescPtr);
Type int32_type = typeConverter.convertType(builder.getI32Type());
Value zero =
createIndexAttrConstant(builder, loc, typeConverter.getIndexType(), 0);
Value three = builder.create<LLVM::ConstantOp>(loc, int32_type,
builder.getI32IntegerAttr(3));
return builder.create<LLVM::GEPOp>(loc, LLVM::LLVMPointerType::get(indexTy),
structPtr, ValueRange({zero, three}));
}
Value UnrankedMemRefDescriptor::size(OpBuilder &builder, Location loc,
LLVMTypeConverter typeConverter,
Value sizeBasePtr, Value index) {
Type indexPtrTy = LLVM::LLVMPointerType::get(typeConverter.getIndexType());
Value sizeStoreGep = builder.create<LLVM::GEPOp>(loc, indexPtrTy, sizeBasePtr,
ValueRange({index}));
return builder.create<LLVM::LoadOp>(loc, sizeStoreGep);
}
void UnrankedMemRefDescriptor::setSize(OpBuilder &builder, Location loc,
LLVMTypeConverter typeConverter,
Value sizeBasePtr, Value index,
Value size) {
Type indexPtrTy = LLVM::LLVMPointerType::get(typeConverter.getIndexType());
Value sizeStoreGep = builder.create<LLVM::GEPOp>(loc, indexPtrTy, sizeBasePtr,
ValueRange({index}));
builder.create<LLVM::StoreOp>(loc, size, sizeStoreGep);
}
Value UnrankedMemRefDescriptor::strideBasePtr(OpBuilder &builder, Location loc,
LLVMTypeConverter &typeConverter,
Value sizeBasePtr, Value rank) {
Type indexPtrTy = LLVM::LLVMPointerType::get(typeConverter.getIndexType());
return builder.create<LLVM::GEPOp>(loc, indexPtrTy, sizeBasePtr,
ValueRange({rank}));
}
Value UnrankedMemRefDescriptor::stride(OpBuilder &builder, Location loc,
LLVMTypeConverter typeConverter,
Value strideBasePtr, Value index,
Value stride) {
Type indexPtrTy = LLVM::LLVMPointerType::get(typeConverter.getIndexType());
Value strideStoreGep = builder.create<LLVM::GEPOp>(
loc, indexPtrTy, strideBasePtr, ValueRange({index}));
return builder.create<LLVM::LoadOp>(loc, strideStoreGep);
}
void UnrankedMemRefDescriptor::setStride(OpBuilder &builder, Location loc,
LLVMTypeConverter typeConverter,
Value strideBasePtr, Value index,
Value stride) {
Type indexPtrTy = LLVM::LLVMPointerType::get(typeConverter.getIndexType());
Value strideStoreGep = builder.create<LLVM::GEPOp>(
loc, indexPtrTy, strideBasePtr, ValueRange({index}));
builder.create<LLVM::StoreOp>(loc, stride, strideStoreGep);
}