//===-- include/flang/Evaluate/variable.h -----------------------*- C++ -*-===//
//
// 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
//
//===----------------------------------------------------------------------===//
#ifndef FORTRAN_EVALUATE_VARIABLE_H_
#define FORTRAN_EVALUATE_VARIABLE_H_
// Defines data structures to represent data access and function calls
// for use in expressions and assignment statements. Both copy and move
// semantics are supported. The representation adheres closely to the
// Fortran 2018 language standard (q.v.) and uses strong typing to ensure
// that only admissable combinations can be constructed.
#include "call.h"
#include "common.h"
#include "formatting.h"
#include "static-data.h"
#include "type.h"
#include "flang/Common/idioms.h"
#include "flang/Common/reference.h"
#include "flang/Common/template.h"
#include "flang/Parser/char-block.h"
#include <optional>
#include <variant>
#include <vector>
namespace llvm {
class raw_ostream;
}
namespace Fortran::semantics {
class Symbol;
}
namespace Fortran::evaluate {
using semantics::Symbol;
using SymbolRef = common::Reference<const Symbol>;
using SymbolVector = std::vector<SymbolRef>;
// Forward declarations
struct DataRef;
template <typename T> struct Variable;
// Reference a base object in memory. This can be a Fortran symbol,
// static data (e.g., CHARACTER literal), or compiler-created temporary.
struct BaseObject {
EVALUATE_UNION_CLASS_BOILERPLATE(BaseObject)
int Rank() const;
std::optional<Expr<SubscriptInteger>> LEN() const;
llvm::raw_ostream &AsFortran(llvm::raw_ostream &) const;
const Symbol *symbol() const {
if (const auto *result{std::get_if<SymbolRef>(&u)}) {
return &result->get();
} else {
return nullptr;
}
}
std::variant<SymbolRef, StaticDataObject::Pointer> u;
};
// R913 structure-component & C920: Defined to be a multi-part
// data-ref whose last part has no subscripts (or image-selector, although
// that isn't explicit in the document). Pointer and allocatable components
// are not explicitly indirected in this representation.
// Complex components (%RE, %IM) are isolated below in ComplexPart.
// (Type parameter inquiries look like component references but are distinct
// constructs and not represented by this class.)
class Component {
public:
CLASS_BOILERPLATE(Component)
Component(const DataRef &b, const Symbol &c) : base_{b}, symbol_{c} {}
Component(DataRef &&b, const Symbol &c) : base_{std::move(b)}, symbol_{c} {}
Component(common::CopyableIndirection<DataRef> &&b, const Symbol &c)
: base_{std::move(b)}, symbol_{c} {}
const DataRef &base() const { return base_.value(); }
DataRef &base() { return base_.value(); }
const SymbolRef &symbol() const { return symbol_; }
SymbolRef &symbol() { return symbol_; }
int Rank() const;
const Symbol &GetFirstSymbol() const;
const Symbol &GetLastSymbol() const { return symbol_; }
std::optional<Expr<SubscriptInteger>> LEN() const;
bool operator==(const Component &) const;
llvm::raw_ostream &AsFortran(llvm::raw_ostream &) const;
private:
common::CopyableIndirection<DataRef> base_;
SymbolRef symbol_;
};
// A NamedEntity is either a whole Symbol or a component in an instance
// of a derived type. It may be a descriptor.
// TODO: this is basically a symbol with an optional DataRef base;
// could be used to replace Component.
class NamedEntity {
public:
CLASS_BOILERPLATE(NamedEntity)
explicit NamedEntity(const Symbol &symbol) : u_{symbol} {}
explicit NamedEntity(Component &&c) : u_{std::move(c)} {}
bool IsSymbol() const { return std::holds_alternative<SymbolRef>(u_); }
const Symbol &GetFirstSymbol() const;
const Symbol &GetLastSymbol() const;
const Component &GetComponent() const { return std::get<Component>(u_); }
Component &GetComponent() { return std::get<Component>(u_); }
const SymbolRef *UnwrapSymbolRef() const; // null if a Component
SymbolRef *UnwrapSymbolRef();
const Component *UnwrapComponent() const; // null if not a Component
Component *UnwrapComponent();
int Rank() const;
std::optional<Expr<SubscriptInteger>> LEN() const;
bool operator==(const NamedEntity &) const;
llvm::raw_ostream &AsFortran(llvm::raw_ostream &) const;
private:
std::variant<SymbolRef, Component> u_;
};
// R916 type-param-inquiry
// N.B. x%LEN for CHARACTER is rewritten in semantics to LEN(x), which is
// then handled via LEN() member functions in the various classes;
// it becomes a DescriptorInquiry with Field::Len for assumed-length
// CHARACTER objects.
// x%KIND for intrinsic types is similarly rewritten in semantics to
// KIND(x), which is then folded to a constant value.
// "Bare" type parameter references within a derived type definition do
// not have base objects.
class TypeParamInquiry {
public:
using Result = SubscriptInteger;
CLASS_BOILERPLATE(TypeParamInquiry)
TypeParamInquiry(NamedEntity &&x, const Symbol ¶m)
: base_{std::move(x)}, parameter_{param} {}
TypeParamInquiry(std::optional<NamedEntity> &&x, const Symbol ¶m)
: base_{std::move(x)}, parameter_{param} {}
const std::optional<NamedEntity> &base() const { return base_; }
std::optional<NamedEntity> &base() { return base_; }
const Symbol ¶meter() const { return parameter_; }
static constexpr int Rank() { return 0; } // always scalar
bool operator==(const TypeParamInquiry &) const;
llvm::raw_ostream &AsFortran(llvm::raw_ostream &) const;
private:
std::optional<NamedEntity> base_;
SymbolRef parameter_;
};
// R921 subscript-triplet
class Triplet {
public:
Triplet();
DEFAULT_CONSTRUCTORS_AND_ASSIGNMENTS(Triplet)
Triplet(std::optional<Expr<SubscriptInteger>> &&,
std::optional<Expr<SubscriptInteger>> &&,
std::optional<Expr<SubscriptInteger>> &&);
std::optional<Expr<SubscriptInteger>> lower() const;
const Expr<SubscriptInteger> *GetLower() const {
return lower_.has_value() ? &lower_->value() : nullptr;
}
Triplet &set_lower(Expr<SubscriptInteger> &&);
std::optional<Expr<SubscriptInteger>> upper() const;
const Expr<SubscriptInteger> *GetUpper() const {
return upper_.has_value() ? &upper_->value() : nullptr;
}
Triplet &set_upper(Expr<SubscriptInteger> &&);
Expr<SubscriptInteger> stride() const; // N.B. result is not optional<>
const Expr<SubscriptInteger> &GetStride() const { return stride_.value(); }
Triplet &set_stride(Expr<SubscriptInteger> &&);
bool operator==(const Triplet &) const;
llvm::raw_ostream &AsFortran(llvm::raw_ostream &) const;
private:
std::optional<IndirectSubscriptIntegerExpr> lower_, upper_;
IndirectSubscriptIntegerExpr stride_;
};
// R919 subscript when rank 0, R923 vector-subscript when rank 1
struct Subscript {
EVALUATE_UNION_CLASS_BOILERPLATE(Subscript)
explicit Subscript(Expr<SubscriptInteger> &&s)
: u{IndirectSubscriptIntegerExpr::Make(std::move(s))} {}
int Rank() const;
llvm::raw_ostream &AsFortran(llvm::raw_ostream &) const;
std::variant<IndirectSubscriptIntegerExpr, Triplet> u;
};
// R917 array-element, R918 array-section; however, the case of an
// array-section that is a complex-part-designator is represented here
// as a ComplexPart instead. C919 & C925 require that at most one set of
// subscripts have rank greater than 0, but that is not explicit in
// these types.
class ArrayRef {
public:
CLASS_BOILERPLATE(ArrayRef)
ArrayRef(const Symbol &symbol, std::vector<Subscript> &&ss)
: base_{symbol}, subscript_(std::move(ss)) {}
ArrayRef(Component &&c, std::vector<Subscript> &&ss)
: base_{std::move(c)}, subscript_(std::move(ss)) {}
ArrayRef(NamedEntity &&base, std::vector<Subscript> &&ss)
: base_{std::move(base)}, subscript_(std::move(ss)) {}
NamedEntity &base() { return base_; }
const NamedEntity &base() const { return base_; }
std::vector<Subscript> &subscript() { return subscript_; }
const std::vector<Subscript> &subscript() const { return subscript_; }
int size() const { return static_cast<int>(subscript_.size()); }
Subscript &at(int n) { return subscript_.at(n); }
const Subscript &at(int n) const { return subscript_.at(n); }
template <typename A> common::IfNoLvalue<Subscript &, A> emplace_back(A &&x) {
return subscript_.emplace_back(std::move(x));
}
int Rank() const;
const Symbol &GetFirstSymbol() const;
const Symbol &GetLastSymbol() const;
std::optional<Expr<SubscriptInteger>> LEN() const;
bool operator==(const ArrayRef &) const;
llvm::raw_ostream &AsFortran(llvm::raw_ostream &) const;
private:
NamedEntity base_;
std::vector<Subscript> subscript_;
};
// R914 coindexed-named-object
// R924 image-selector, R926 image-selector-spec.
// C825 severely limits the usage of derived types with coarray ultimate
// components: they can't be pointers, allocatables, arrays, coarrays, or
// function results. They can be components of other derived types.
// Although the F'2018 Standard never prohibits multiple image-selectors
// per se in the same data-ref or designator, nor the presence of an
// image-selector after a part-ref with rank, the constraints on the
// derived types that would have be involved make it impossible to declare
// an object that could be referenced in these ways (esp. C748 & C825).
// C930 precludes having both TEAM= and TEAM_NUMBER=.
// TODO C931 prohibits the use of a coindexed object as a stat-variable.
class CoarrayRef {
public:
CLASS_BOILERPLATE(CoarrayRef)
CoarrayRef(SymbolVector &&, std::vector<Subscript> &&,
std::vector<Expr<SubscriptInteger>> &&);
const SymbolVector &base() const { return base_; }
SymbolVector &base() { return base_; }
const std::vector<Subscript> &subscript() const { return subscript_; }
std::vector<Subscript> &subscript() { return subscript_; }
const std::vector<Expr<SubscriptInteger>> &cosubscript() const {
return cosubscript_;
}
std::vector<Expr<SubscriptInteger>> &cosubscript() { return cosubscript_; }
// These integral expressions for STAT= and TEAM= must be variables
// (i.e., Designator or pointer-valued FunctionRef).
std::optional<Expr<SomeInteger>> stat() const;
CoarrayRef &set_stat(Expr<SomeInteger> &&);
std::optional<Expr<SomeInteger>> team() const;
bool teamIsTeamNumber() const { return teamIsTeamNumber_; }
CoarrayRef &set_team(Expr<SomeInteger> &&, bool isTeamNumber = false);
int Rank() const;
const Symbol &GetFirstSymbol() const;
const Symbol &GetLastSymbol() const;
NamedEntity GetBase() const;
std::optional<Expr<SubscriptInteger>> LEN() const;
bool operator==(const CoarrayRef &) const;
llvm::raw_ostream &AsFortran(llvm::raw_ostream &) const;
private:
SymbolVector base_;
std::vector<Subscript> subscript_;
std::vector<Expr<SubscriptInteger>> cosubscript_;
std::optional<common::CopyableIndirection<Expr<SomeInteger>>> stat_, team_;
bool teamIsTeamNumber_{false}; // false: TEAM=, true: TEAM_NUMBER=
};
// R911 data-ref is defined syntactically as a series of part-refs, which
// would be far too expressive if the constraints were ignored. Here, the
// possible outcomes are spelled out. Note that a data-ref cannot include
// a terminal substring range or complex component designator; use
// R901 designator for that.
struct DataRef {
EVALUATE_UNION_CLASS_BOILERPLATE(DataRef)
int Rank() const;
const Symbol &GetFirstSymbol() const;
const Symbol &GetLastSymbol() const;
std::optional<Expr<SubscriptInteger>> LEN() const;
llvm::raw_ostream &AsFortran(llvm::raw_ostream &) const;
std::variant<SymbolRef, Component, ArrayRef, CoarrayRef> u;
};
// R908 substring, R909 parent-string, R910 substring-range.
// The base object of a substring can be a literal.
// In the F2018 standard, substrings of array sections are parsed as
// variants of sections instead.
class Substring {
using Parent = std::variant<DataRef, StaticDataObject::Pointer>;
public:
CLASS_BOILERPLATE(Substring)
Substring(DataRef &&parent, std::optional<Expr<SubscriptInteger>> &&lower,
std::optional<Expr<SubscriptInteger>> &&upper)
: parent_{std::move(parent)} {
SetBounds(lower, upper);
}
Substring(StaticDataObject::Pointer &&parent,
std::optional<Expr<SubscriptInteger>> &&lower,
std::optional<Expr<SubscriptInteger>> &&upper)
: parent_{std::move(parent)} {
SetBounds(lower, upper);
}
Expr<SubscriptInteger> lower() const;
Substring &set_lower(Expr<SubscriptInteger> &&);
std::optional<Expr<SubscriptInteger>> upper() const;
Substring &set_upper(Expr<SubscriptInteger> &&);
const Parent &parent() const { return parent_; }
Parent &parent() { return parent_; }
int Rank() const;
template <typename A> const A *GetParentIf() const {
return std::get_if<A>(&parent_);
}
BaseObject GetBaseObject() const;
const Symbol *GetLastSymbol() const;
std::optional<Expr<SubscriptInteger>> LEN() const;
bool operator==(const Substring &) const;
llvm::raw_ostream &AsFortran(llvm::raw_ostream &) const;
std::optional<Expr<SomeCharacter>> Fold(FoldingContext &);
private:
void SetBounds(std::optional<Expr<SubscriptInteger>> &,
std::optional<Expr<SubscriptInteger>> &);
Parent parent_;
std::optional<IndirectSubscriptIntegerExpr> lower_, upper_;
};
// R915 complex-part-designator
// In the F2018 standard, complex parts of array sections are parsed as
// variants of sections instead.
class ComplexPart {
public:
ENUM_CLASS(Part, RE, IM)
CLASS_BOILERPLATE(ComplexPart)
ComplexPart(DataRef &&z, Part p) : complex_{std::move(z)}, part_{p} {}
DataRef &complex() { return complex_; }
const DataRef &complex() const { return complex_; }
Part part() const { return part_; }
int Rank() const;
const Symbol &GetFirstSymbol() const { return complex_.GetFirstSymbol(); }
const Symbol &GetLastSymbol() const { return complex_.GetLastSymbol(); }
bool operator==(const ComplexPart &) const;
llvm::raw_ostream &AsFortran(llvm::raw_ostream &) const;
private:
DataRef complex_;
Part part_;
};
// R901 designator is the most general data reference object, apart from
// calls to pointer-valued functions. Its variant holds everything that
// a DataRef can, and possibly also a substring reference or a
// complex component (%RE/%IM) reference.
template <typename T> class Designator {
using DataRefs = std::decay_t<decltype(DataRef::u)>;
using MaybeSubstring =
std::conditional_t<T::category == TypeCategory::Character,
std::variant<Substring>, std::variant<>>;
using MaybeComplexPart = std::conditional_t<T::category == TypeCategory::Real,
std::variant<ComplexPart>, std::variant<>>;
using Variant =
common::CombineVariants<DataRefs, MaybeSubstring, MaybeComplexPart>;
public:
using Result = T;
static_assert(
IsSpecificIntrinsicType<Result> || std::is_same_v<Result, SomeDerived>);
EVALUATE_UNION_CLASS_BOILERPLATE(Designator)
Designator(const DataRef &that) : u{common::CopyVariant<Variant>(that.u)} {}
Designator(DataRef &&that)
: u{common::MoveVariant<Variant>(std::move(that.u))} {}
std::optional<DynamicType> GetType() const;
int Rank() const;
BaseObject GetBaseObject() const;
const Symbol *GetLastSymbol() const;
std::optional<Expr<SubscriptInteger>> LEN() const;
llvm::raw_ostream &AsFortran(llvm::raw_ostream &o) const;
Variant u;
};
FOR_EACH_CHARACTER_KIND(extern template class Designator, )
class DescriptorInquiry {
public:
using Result = SubscriptInteger;
ENUM_CLASS(Field, LowerBound, Extent, Stride, Rank, Len)
CLASS_BOILERPLATE(DescriptorInquiry)
DescriptorInquiry(const NamedEntity &, Field, int = 0);
DescriptorInquiry(NamedEntity &&, Field, int = 0);
NamedEntity &base() { return base_; }
const NamedEntity &base() const { return base_; }
Field field() const { return field_; }
int dimension() const { return dimension_; }
static constexpr int Rank() { return 0; } // always scalar
bool operator==(const DescriptorInquiry &) const;
llvm::raw_ostream &AsFortran(llvm::raw_ostream &) const;
private:
NamedEntity base_;
Field field_;
int dimension_{0}; // zero-based
};
#define INSTANTIATE_VARIABLE_TEMPLATES \
FOR_EACH_SPECIFIC_TYPE(template class Designator, )
} // namespace Fortran::evaluate
#endif // FORTRAN_EVALUATE_VARIABLE_H_
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