1 | //===-- lib/Semantics/definable.h -------------------------------*- C++ -*-===// |
2 | // |
3 | // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. |
4 | // See https://llvm.org/LICENSE.txt for license information. |
5 | // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception |
6 | // |
7 | //===----------------------------------------------------------------------===// |
8 | |
9 | #ifndef FORTRAN_SEMANTICS_DEFINABLE_H_ |
10 | #define FORTRAN_SEMANTICS_DEFINABLE_H_ |
11 | |
12 | // Utilities for checking the definability of variables and pointers in context, |
13 | // including checks for attempted definitions in PURE subprograms. |
14 | // Fortran 2018 C1101, C1158, C1594, &c. |
15 | |
16 | #include "flang/Common/enum-set.h" |
17 | #include "flang/Common/idioms.h" |
18 | #include "flang/Evaluate/expression.h" |
19 | #include "flang/Parser/char-block.h" |
20 | #include "flang/Parser/message.h" |
21 | #include <optional> |
22 | |
23 | namespace Fortran::semantics { |
24 | |
25 | class Symbol; |
26 | class Scope; |
27 | |
28 | ENUM_CLASS(DefinabilityFlag, |
29 | VectorSubscriptIsOk, // a vector subscript may appear (i.e., assignment) |
30 | DuplicatesAreOk, // vector subscript may have duplicates |
31 | PointerDefinition, // a pointer is being defined, not its target |
32 | AcceptAllocatable, // treat allocatable as if it were a pointer |
33 | SourcedAllocation, // ALLOCATE(a,SOURCE=) |
34 | PolymorphicOkInPure, // don't check for polymorphic type in pure subprogram |
35 | DoNotNoteDefinition, // context does not imply definition |
36 | AllowEventLockOrNotifyType, PotentialDeallocation) |
37 | |
38 | using DefinabilityFlags = |
39 | common::EnumSet<DefinabilityFlag, DefinabilityFlag_enumSize>; |
40 | |
41 | // Tests a symbol or LHS variable or pointer for definability in a given scope. |
42 | // When the entity is not definable, returns a Message suitable for attachment |
43 | // to an error or warning message (as a "because: addendum) to explain why the |
44 | // entity cannot be defined. |
45 | // When the entity can be defined in that context, returns std::nullopt. |
46 | std::optional<parser::Message> WhyNotDefinable( |
47 | parser::CharBlock, const Scope &, DefinabilityFlags, const Symbol &); |
48 | std::optional<parser::Message> WhyNotDefinable(parser::CharBlock, const Scope &, |
49 | DefinabilityFlags, const evaluate::Expr<evaluate::SomeType> &); |
50 | |
51 | // If a symbol would not be definable in a pure scope, or not be usable as the |
52 | // target of a pointer assignment in a pure scope, return a constant string |
53 | // describing why. |
54 | const char *WhyBaseObjectIsSuspicious(const Symbol &, const Scope &); |
55 | |
56 | } // namespace Fortran::semantics |
57 | #endif // FORTRAN_SEMANTICS_DEFINABLE_H_ |
58 | |