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//===-- VectorSubscripts.cpp -- Vector subscripts tools -------------------===//
//
// 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
//
//===----------------------------------------------------------------------===//
//
// Coding style: https://mlir.llvm.org/getting_started/DeveloperGuide/
//
//===----------------------------------------------------------------------===//
#include "flang/Lower/VectorSubscripts.h"
#include "flang/Lower/AbstractConverter.h"
#include "flang/Lower/Support/Utils.h"
#include "flang/Optimizer/Builder/Character.h"
#include "flang/Optimizer/Builder/Complex.h"
#include "flang/Optimizer/Builder/FIRBuilder.h"
#include "flang/Optimizer/Builder/Todo.h"
#include "flang/Semantics/expression.h"
namespace {
/// Helper class to lower a designator containing vector subscripts into a
/// lowered representation that can be worked with.
class VectorSubscriptBoxBuilder {
public:
VectorSubscriptBoxBuilder(mlir::Location loc,
Fortran::lower::AbstractConverter &converter,
Fortran::lower::StatementContext &stmtCtx)
: converter{converter}, stmtCtx{stmtCtx}, loc{loc} {}
Fortran::lower::VectorSubscriptBox gen(const Fortran::lower::SomeExpr &expr) {
elementType = genDesignator(expr);
return Fortran::lower::VectorSubscriptBox(
std::move(loweredBase), std::move(loweredSubscripts),
std::move(componentPath), substringBounds, elementType);
}
private:
using LoweredVectorSubscript =
Fortran::lower::VectorSubscriptBox::LoweredVectorSubscript;
using LoweredTriplet = Fortran::lower::VectorSubscriptBox::LoweredTriplet;
using LoweredSubscript = Fortran::lower::VectorSubscriptBox::LoweredSubscript;
using MaybeSubstring = Fortran::lower::VectorSubscriptBox::MaybeSubstring;
/// genDesignator unwraps a Designator<T> and calls `gen` on what the
/// designator actually contains.
template <typename A>
mlir::Type genDesignator(const A &) {
fir::emitFatalError(loc, "expr must contain a designator");
}
template <typename T>
mlir::Type genDesignator(const Fortran::evaluate::Expr<T> &expr) {
using ExprVariant = decltype(Fortran::evaluate::Expr<T>::u);
using Designator = Fortran::evaluate::Designator<T>;
if constexpr (Fortran::common::HasMember<Designator, ExprVariant>) {
const auto &designator = std::get<Designator>(expr.u);
return std::visit([&](const auto &x) { return gen(x); }, designator.u);
} else {
return std::visit([&](const auto &x) { return genDesignator(x); },
expr.u);
}
}
// The gen(X) methods visit X to lower its base and subscripts and return the
// type of X elements.
mlir::Type gen(const Fortran::evaluate::DataRef &dataRef) {
return std::visit([&](const auto &ref) -> mlir::Type { return gen(ref); },
dataRef.u);
}
mlir::Type gen(const Fortran::evaluate::SymbolRef &symRef) {
// Never visited because expr lowering is used to lowered the ranked
// ArrayRef.
fir::emitFatalError(
loc, "expected at least one ArrayRef with vector susbcripts");
}
mlir::Type gen(const Fortran::evaluate::Substring &substring) {
// StaticDataObject::Pointer bases are constants and cannot be
// subscripted, so the base must be a DataRef here.
mlir::Type baseElementType =
gen(std::get<Fortran::evaluate::DataRef>(substring.parent()));
fir::FirOpBuilder &builder = converter.getFirOpBuilder();
mlir::Type idxTy = builder.getIndexType();
mlir::Value lb = genScalarValue(substring.lower());
substringBounds.emplace_back(builder.createConvert(loc, idxTy, lb));
if (const auto &ubExpr = substring.upper()) {
mlir::Value ub = genScalarValue(*ubExpr);
substringBounds.emplace_back(builder.createConvert(loc, idxTy, ub));
}
return baseElementType;
}
mlir::Type gen(const Fortran::evaluate::ComplexPart &complexPart) {
auto complexType = gen(complexPart.complex());
fir::FirOpBuilder &builder = converter.getFirOpBuilder();
mlir::Type i32Ty = builder.getI32Type(); // llvm's GEP requires i32
mlir::Value offset = builder.createIntegerConstant(
loc, i32Ty,
complexPart.part() == Fortran::evaluate::ComplexPart::Part::RE ? 0 : 1);
componentPath.emplace_back(offset);
return fir::factory::Complex{builder, loc}.getComplexPartType(complexType);
}
mlir::Type gen(const Fortran::evaluate::Component &component) {
auto recTy = gen(component.base()).cast<fir::RecordType>();
const Fortran::semantics::Symbol &componentSymbol =
component.GetLastSymbol();
// Parent components will not be found here, they are not part
// of the FIR type and cannot be used in the path yet.
if (componentSymbol.test(Fortran::semantics::Symbol::Flag::ParentComp))
TODO(loc, "reference to parent component");
mlir::Type fldTy = fir::FieldType::get(&converter.getMLIRContext());
llvm::StringRef componentName = toStringRef(componentSymbol.name());
// Parameters threading in field_index is not yet very clear. We only
// have the ones of the ranked array ref at hand, but it looks like
// the fir.field_index expects the one of the direct base.
if (recTy.getNumLenParams() != 0)
TODO(loc, "threading length parameters in field index op");
fir::FirOpBuilder &builder = converter.getFirOpBuilder();
componentPath.emplace_back(builder.create<fir::FieldIndexOp>(
loc, fldTy, componentName, recTy, /*typeParams*/ std::nullopt));
return fir::unwrapSequenceType(recTy.getType(componentName));
}
mlir::Type gen(const Fortran::evaluate::ArrayRef &arrayRef) {
auto isTripletOrVector =
[](const Fortran::evaluate::Subscript &subscript) -> bool {
return std::visit(
Fortran::common::visitors{
[](const Fortran::evaluate::IndirectSubscriptIntegerExpr &expr) {
return expr.value().Rank() != 0;
},
[&](const Fortran::evaluate::Triplet &) { return true; }},
subscript.u);
};
if (llvm::any_of(arrayRef.subscript(), isTripletOrVector))
return genRankedArrayRefSubscriptAndBase(arrayRef);
// This is a scalar ArrayRef (only scalar indexes), collect the indexes and
// visit the base that must contain another arrayRef with the vector
// subscript.
mlir::Type elementType = gen(namedEntityToDataRef(arrayRef.base()));
for (const Fortran::evaluate::Subscript &subscript : arrayRef.subscript()) {
const auto &expr =
std::get<Fortran::evaluate::IndirectSubscriptIntegerExpr>(
subscript.u);
componentPath.emplace_back(genScalarValue(expr.value()));
}
return elementType;
}
/// Lower the subscripts and base of the ArrayRef that is an array (there must
/// be one since there is a vector subscript, and there can only be one
/// according to C925).
mlir::Type genRankedArrayRefSubscriptAndBase(
const Fortran::evaluate::ArrayRef &arrayRef) {
// Lower the save the base
Fortran::lower::SomeExpr baseExpr = namedEntityToExpr(arrayRef.base());
loweredBase = converter.genExprAddr(baseExpr, stmtCtx);
// Lower and save the subscripts
fir::FirOpBuilder &builder = converter.getFirOpBuilder();
mlir::Type idxTy = builder.getIndexType();
mlir::Value one = builder.createIntegerConstant(loc, idxTy, 1);
for (const auto &subscript : llvm::enumerate(arrayRef.subscript())) {
std::visit(
Fortran::common::visitors{
[&](const Fortran::evaluate::IndirectSubscriptIntegerExpr &expr) {
if (expr.value().Rank() == 0) {
// Simple scalar subscript
loweredSubscripts.emplace_back(genScalarValue(expr.value()));
} else {
// Vector subscript.
// Remove conversion if any to avoid temp creation that may
// have been added by the front-end to avoid the creation of a
// temp array value.
auto vector = converter.genExprAddr(
ignoreEvConvert(expr.value()), stmtCtx);
mlir::Value size =
fir::factory::readExtent(builder, loc, vector, /*dim=*/0);
size = builder.createConvert(loc, idxTy, size);
loweredSubscripts.emplace_back(
LoweredVectorSubscript{std::move(vector), size});
}
},
[&](const Fortran::evaluate::Triplet &triplet) {
mlir::Value lb, ub;
if (const auto &lbExpr = triplet.lower())
lb = genScalarValue(*lbExpr);
else
lb = fir::factory::readLowerBound(builder, loc, loweredBase,
subscript.index(), one);
if (const auto &ubExpr = triplet.upper())
ub = genScalarValue(*ubExpr);
else
ub = fir::factory::readExtent(builder, loc, loweredBase,
subscript.index());
lb = builder.createConvert(loc, idxTy, lb);
ub = builder.createConvert(loc, idxTy, ub);
mlir::Value stride = genScalarValue(triplet.stride());
stride = builder.createConvert(loc, idxTy, stride);
loweredSubscripts.emplace_back(LoweredTriplet{lb, ub, stride});
},
},
subscript.value().u);
}
return fir::unwrapSequenceType(
fir::unwrapPassByRefType(fir::getBase(loweredBase).getType()));
}
mlir::Type gen(const Fortran::evaluate::CoarrayRef &) {
// Is this possible/legal ?
TODO(loc, "coarray: reference to coarray object with vector subscript in "
"IO input");
}
template <typename A>
mlir::Value genScalarValue(const A &expr) {
return fir::getBase(converter.genExprValue(toEvExpr(expr), stmtCtx));
}
Fortran::evaluate::DataRef
namedEntityToDataRef(const Fortran::evaluate::NamedEntity &namedEntity) {
if (namedEntity.IsSymbol())
return Fortran::evaluate::DataRef{namedEntity.GetFirstSymbol()};
return Fortran::evaluate::DataRef{namedEntity.GetComponent()};
}
Fortran::lower::SomeExpr
namedEntityToExpr(const Fortran::evaluate::NamedEntity &namedEntity) {
return Fortran::evaluate::AsGenericExpr(namedEntityToDataRef(namedEntity))
.value();
}
Fortran::lower::AbstractConverter &converter;
Fortran::lower::StatementContext &stmtCtx;
mlir::Location loc;
/// Elements of VectorSubscriptBox being built.
fir::ExtendedValue loweredBase;
llvm::SmallVector<LoweredSubscript, 16> loweredSubscripts;
llvm::SmallVector<mlir::Value> componentPath;
MaybeSubstring substringBounds;
mlir::Type elementType;
};
} // namespace
Fortran::lower::VectorSubscriptBox Fortran::lower::genVectorSubscriptBox(
mlir::Location loc, Fortran::lower::AbstractConverter &converter,
Fortran::lower::StatementContext &stmtCtx,
const Fortran::lower::SomeExpr &expr) {
return VectorSubscriptBoxBuilder(loc, converter, stmtCtx).gen(expr);
}
template <typename LoopType, typename Generator>
mlir::Value Fortran::lower::VectorSubscriptBox::loopOverElementsBase(
fir::FirOpBuilder &builder, mlir::Location loc,
const Generator &elementalGenerator,
[[maybe_unused]] mlir::Value initialCondition) {
mlir::Value shape = builder.createShape(loc, loweredBase);
mlir::Value slice = createSlice(builder, loc);
// Create loop nest for triplets and vector subscripts in column
// major order.
llvm::SmallVector<mlir::Value> inductionVariables;
LoopType outerLoop;
for (auto [lb, ub, step] : genLoopBounds(builder, loc)) {
LoopType loop;
if constexpr (std::is_same_v<LoopType, fir::IterWhileOp>) {
loop =
builder.create<fir::IterWhileOp>(loc, lb, ub, step, initialCondition);
initialCondition = loop.getIterateVar();
if (!outerLoop)
outerLoop = loop;
else
builder.create<fir::ResultOp>(loc, loop.getResult(0));
} else {
loop =
builder.create<fir::DoLoopOp>(loc, lb, ub, step, /*unordered=*/false);
if (!outerLoop)
outerLoop = loop;
}
builder.setInsertionPointToStart(loop.getBody());
inductionVariables.push_back(loop.getInductionVar());
}
assert(outerLoop && !inductionVariables.empty() &&
"at least one loop should be created");
fir::ExtendedValue elem =
getElementAt(builder, loc, shape, slice, inductionVariables);
if constexpr (std::is_same_v<LoopType, fir::IterWhileOp>) {
auto res = elementalGenerator(elem);
builder.create<fir::ResultOp>(loc, res);
builder.setInsertionPointAfter(outerLoop);
return outerLoop.getResult(0);
} else {
elementalGenerator(elem);
builder.setInsertionPointAfter(outerLoop);
return {};
}
}
void Fortran::lower::VectorSubscriptBox::loopOverElements(
fir::FirOpBuilder &builder, mlir::Location loc,
const ElementalGenerator &elementalGenerator) {
mlir::Value initialCondition;
loopOverElementsBase<fir::DoLoopOp, ElementalGenerator>(
builder, loc, elementalGenerator, initialCondition);
}
mlir::Value Fortran::lower::VectorSubscriptBox::loopOverElementsWhile(
fir::FirOpBuilder &builder, mlir::Location loc,
const ElementalGeneratorWithBoolReturn &elementalGenerator,
mlir::Value initialCondition) {
return loopOverElementsBase<fir::IterWhileOp,
ElementalGeneratorWithBoolReturn>(
builder, loc, elementalGenerator, initialCondition);
}
mlir::Value
Fortran::lower::VectorSubscriptBox::createSlice(fir::FirOpBuilder &builder,
mlir::Location loc) {
mlir::Type idxTy = builder.getIndexType();
llvm::SmallVector<mlir::Value> triples;
mlir::Value one = builder.createIntegerConstant(loc, idxTy, 1);
auto undef = builder.create<fir::UndefOp>(loc, idxTy);
for (const LoweredSubscript &subscript : loweredSubscripts)
std::visit(Fortran::common::visitors{
[&](const LoweredTriplet &triplet) {
triples.emplace_back(triplet.lb);
triples.emplace_back(triplet.ub);
triples.emplace_back(triplet.stride);
},
[&](const LoweredVectorSubscript &vector) {
triples.emplace_back(one);
triples.emplace_back(vector.size);
triples.emplace_back(one);
},
[&](const mlir::Value &i) {
triples.emplace_back(i);
triples.emplace_back(undef);
triples.emplace_back(undef);
},
},
subscript);
return builder.create<fir::SliceOp>(loc, triples, componentPath);
}
llvm::SmallVector<std::tuple<mlir::Value, mlir::Value, mlir::Value>>
Fortran::lower::VectorSubscriptBox::genLoopBounds(fir::FirOpBuilder &builder,
mlir::Location loc) {
mlir::Type idxTy = builder.getIndexType();
mlir::Value one = builder.createIntegerConstant(loc, idxTy, 1);
mlir::Value zero = builder.createIntegerConstant(loc, idxTy, 0);
llvm::SmallVector<std::tuple<mlir::Value, mlir::Value, mlir::Value>> bounds;
size_t dimension = loweredSubscripts.size();
for (const LoweredSubscript &subscript : llvm::reverse(loweredSubscripts)) {
--dimension;
if (std::holds_alternative<mlir::Value>(subscript))
continue;
mlir::Value lb, ub, step;
if (const auto *triplet = std::get_if<LoweredTriplet>(&subscript)) {
mlir::Value extent = builder.genExtentFromTriplet(
loc, triplet->lb, triplet->ub, triplet->stride, idxTy);
mlir::Value baseLb = fir::factory::readLowerBound(
builder, loc, loweredBase, dimension, one);
baseLb = builder.createConvert(loc, idxTy, baseLb);
lb = baseLb;
ub = builder.create<mlir::arith::SubIOp>(loc, idxTy, extent, one);
ub = builder.create<mlir::arith::AddIOp>(loc, idxTy, ub, baseLb);
step = one;
} else {
const auto &vector = std::get<LoweredVectorSubscript>(subscript);
lb = zero;
ub = builder.create<mlir::arith::SubIOp>(loc, idxTy, vector.size, one);
step = one;
}
bounds.emplace_back(lb, ub, step);
}
return bounds;
}
fir::ExtendedValue Fortran::lower::VectorSubscriptBox::getElementAt(
fir::FirOpBuilder &builder, mlir::Location loc, mlir::Value shape,
mlir::Value slice, mlir::ValueRange inductionVariables) {
/// Generate the indexes for the array_coor inside the loops.
mlir::Type idxTy = builder.getIndexType();
llvm::SmallVector<mlir::Value> indexes;
size_t inductionIdx = inductionVariables.size() - 1;
for (const LoweredSubscript &subscript : loweredSubscripts)
std::visit(Fortran::common::visitors{
[&](const LoweredTriplet &triplet) {
indexes.emplace_back(inductionVariables[inductionIdx--]);
},
[&](const LoweredVectorSubscript &vector) {
mlir::Value vecIndex = inductionVariables[inductionIdx--];
mlir::Value vecBase = fir::getBase(vector.vector);
mlir::Type vecEleTy = fir::unwrapSequenceType(
fir::unwrapPassByRefType(vecBase.getType()));
mlir::Type refTy = builder.getRefType(vecEleTy);
auto vecEltRef = builder.create<fir::CoordinateOp>(
loc, refTy, vecBase, vecIndex);
auto vecElt =
builder.create<fir::LoadOp>(loc, vecEleTy, vecEltRef);
indexes.emplace_back(
builder.createConvert(loc, idxTy, vecElt));
},
[&](const mlir::Value &i) {
indexes.emplace_back(builder.createConvert(loc, idxTy, i));
},
},
subscript);
mlir::Type refTy = builder.getRefType(getElementType());
auto elementAddr = builder.create<fir::ArrayCoorOp>(
loc, refTy, fir::getBase(loweredBase), shape, slice, indexes,
fir::getTypeParams(loweredBase));
fir::ExtendedValue element = fir::factory::arraySectionElementToExtendedValue(
builder, loc, loweredBase, elementAddr, slice);
if (!substringBounds.empty()) {
const fir::CharBoxValue *charBox = element.getCharBox();
assert(charBox && "substring requires CharBox base");
fir::factory::CharacterExprHelper helper{builder, loc};
return helper.createSubstring(*charBox, substringBounds);
}
return element;
}