| 1 | //===-- lib/Semantics/definable.h -------------------------------*- C++ -*-===// |
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| 2 | // |
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| 3 | // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. |
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| 4 | // See https://llvm.org/LICENSE.txt for license information. |
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| 5 | // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception |
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| 6 | // |
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| 7 | //===----------------------------------------------------------------------===// |
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| 8 | |
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| 9 | #ifndef FORTRAN_SEMANTICS_DEFINABLE_H_ |
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| 10 | #define FORTRAN_SEMANTICS_DEFINABLE_H_ |
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| 11 | |
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| 12 | // Utilities for checking the definability of variables and pointers in context, |
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| 13 | // including checks for attempted definitions in PURE subprograms. |
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| 14 | // Fortran 2018 C1101, C1158, C1594, &c. |
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| 15 | |
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| 16 | #include "flang/Common/enum-set.h" |
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| 17 | #include "flang/Common/idioms.h" |
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| 18 | #include "flang/Evaluate/expression.h" |
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| 19 | #include "flang/Parser/char-block.h" |
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| 20 | #include "flang/Parser/message.h" |
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| 21 | #include <optional> |
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| 22 | |
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| 23 | namespace Fortran::semantics { |
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| 24 | |
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| 25 | class Symbol; |
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| 26 | class Scope; |
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| 27 | |
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| 28 | ENUM_CLASS(DefinabilityFlag, |
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| 29 | VectorSubscriptIsOk, // a vector subscript may appear (i.e., assignment) |
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| 30 | DuplicatesAreOk, // vector subscript may have duplicates |
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| 31 | PointerDefinition, // a pointer is being defined, not its target |
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| 32 | AcceptAllocatable, // treat allocatable as if it were a pointer |
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| 33 | PolymorphicOkInPure) // don't check for polymorphic type in pure subprogram |
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| 34 | |
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| 35 | using DefinabilityFlags = |
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| 36 | common::EnumSet<DefinabilityFlag, DefinabilityFlag_enumSize>; |
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| 37 | |
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| 38 | // Tests a symbol or LHS variable or pointer for definability in a given scope. |
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| 39 | // When the entity is not definable, returns a "because:" Message suitable for |
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| 40 | // attachment to an error message to explain why the entity cannot be defined. |
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| 41 | // When the entity can be defined in that context, returns std::nullopt. |
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| 42 | std::optional<parser::Message> WhyNotDefinable( |
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| 43 | parser::CharBlock, const Scope &, DefinabilityFlags, const Symbol &); |
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| 44 | std::optional<parser::Message> WhyNotDefinable(parser::CharBlock, const Scope &, |
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| 45 | DefinabilityFlags, const evaluate::Expr<evaluate::SomeType> &); |
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| 46 | |
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| 47 | // If a symbol would not be definable in a pure scope, or not be usable as the |
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| 48 | // target of a pointer assignment in a pure scope, return a constant string |
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| 49 | // describing why. |
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| 50 | const char *WhyBaseObjectIsSuspicious(const Symbol &, const Scope &); |
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| 51 | |
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| 52 | } // namespace Fortran::semantics |
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| 53 | #endif // FORTRAN_SEMANTICS_DEFINABLE_H_ |
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| 54 | |
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