xref: /llvm-project/flang/lib/Evaluate/type.cpp (revision 0a10e88915167c88443dd58883e01d543963e40e) 
1 //===-- lib/Evaluate/type.cpp ---------------------------------------------===//
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 #include "flang/Evaluate/type.h"
10 #include "flang/Common/idioms.h"
11 #include "flang/Evaluate/expression.h"
12 #include "flang/Evaluate/fold.h"
13 #include "flang/Evaluate/target.h"
14 #include "flang/Parser/characters.h"
15 #include "flang/Semantics/scope.h"
16 #include "flang/Semantics/symbol.h"
17 #include "flang/Semantics/tools.h"
18 #include "flang/Semantics/type.h"
19 #include <algorithm>
20 #include <optional>
21 #include <string>
22 
23 // IsDescriptor() predicate: true when a symbol is implemented
24 // at runtime with a descriptor.
25 namespace Fortran::semantics {
26 
27 static bool IsDescriptor(const DeclTypeSpec *type) {
28   if (type) {
29     if (auto dynamicType{evaluate::DynamicType::From(*type)}) {
30       return dynamicType->RequiresDescriptor();
31     }
32   }
33   return false;
34 }
35 
36 static bool IsDescriptor(const ObjectEntityDetails &details) {
37   if (IsDescriptor(details.type()) || details.IsAssumedRank()) {
38     return true;
39   }
40   std::size_t j{0};
41   for (const ShapeSpec &shapeSpec : details.shape()) {
42     ++j;
43     if (const auto &lb{shapeSpec.lbound().GetExplicit()};
44         !lb || !IsConstantExpr(*lb)) {
45       return true;
46     }
47     if (const auto &ub{shapeSpec.ubound().GetExplicit()}) {
48       if (!IsConstantExpr(*ub)) {
49         return true;
50       }
51     } else if (j == details.shape().size() && details.isDummy()) {
52       // assumed size array
53     } else {
54       return true;
55     }
56   }
57   return false;
58 }
59 
60 bool IsDescriptor(const Symbol &symbol) {
61   return common::visit(
62       common::visitors{
63           [&](const ObjectEntityDetails &d) {
64             return IsAllocatableOrPointer(symbol) || IsDescriptor(d);
65           },
66           [&](const ProcEntityDetails &d) { return false; },
67           [&](const EntityDetails &d) { return IsDescriptor(d.type()); },
68           [](const AssocEntityDetails &d) {
69             if (const auto &expr{d.expr()}) {
70               if (expr->Rank() > 0) {
71                 return true;
72               }
73               if (const auto dynamicType{expr->GetType()}) {
74                 if (dynamicType->RequiresDescriptor()) {
75                   return true;
76                 }
77               }
78             }
79             return false;
80           },
81           [](const SubprogramDetails &d) {
82             return d.isFunction() && IsDescriptor(d.result());
83           },
84           [](const UseDetails &d) { return IsDescriptor(d.symbol()); },
85           [](const HostAssocDetails &d) { return IsDescriptor(d.symbol()); },
86           [](const auto &) { return false; },
87       },
88       symbol.details());
89 }
90 
91 bool IsPassedViaDescriptor(const Symbol &symbol) {
92   if (!IsDescriptor(symbol)) {
93     return false;
94   }
95   if (IsAllocatableOrPointer(symbol)) {
96     return true;
97   }
98   if (const auto *object{
99           symbol.GetUltimate().detailsIf<ObjectEntityDetails>()}) {
100     if (object->isDummy()) {
101       if (object->type() &&
102           object->type()->category() == DeclTypeSpec::Character) {
103         return false;
104       }
105       if (object->IsAssumedSize()) {
106         return false;
107       }
108       bool isExplicitShape{true};
109       for (const ShapeSpec &shapeSpec : object->shape()) {
110         if (!shapeSpec.lbound().GetExplicit() ||
111             !shapeSpec.ubound().GetExplicit()) {
112           isExplicitShape = false;
113           break;
114         }
115       }
116       if (isExplicitShape) {
117         return false; // explicit shape but non-constant bounds
118       }
119     }
120   }
121   return true;
122 }
123 } // namespace Fortran::semantics
124 
125 namespace Fortran::evaluate {
126 
127 DynamicType::DynamicType(int k, const semantics::ParamValue &pv)
128     : category_{TypeCategory::Character}, kind_{k} {
129   CHECK(IsValidKindOfIntrinsicType(category_, kind_));
130   if (auto n{ToInt64(pv.GetExplicit())}) {
131     knownLength_ = *n > 0 ? *n : 0;
132   } else {
133     charLengthParamValue_ = &pv;
134   }
135 }
136 
137 template <typename A> inline bool PointeeComparison(const A *x, const A *y) {
138   return x == y || (x && y && *x == *y);
139 }
140 
141 bool DynamicType::operator==(const DynamicType &that) const {
142   return category_ == that.category_ && kind_ == that.kind_ &&
143       PointeeComparison(charLengthParamValue_, that.charLengthParamValue_) &&
144       knownLength().has_value() == that.knownLength().has_value() &&
145       (!knownLength() || *knownLength() == *that.knownLength()) &&
146       PointeeComparison(derived_, that.derived_);
147 }
148 
149 std::optional<Expr<SubscriptInteger>> DynamicType::GetCharLength() const {
150   if (category_ == TypeCategory::Character) {
151     if (knownLength()) {
152       return AsExpr(Constant<SubscriptInteger>(*knownLength()));
153     } else if (charLengthParamValue_) {
154       if (auto length{charLengthParamValue_->GetExplicit()}) {
155         return ConvertToType<SubscriptInteger>(std::move(*length));
156       }
157     }
158   }
159   return std::nullopt;
160 }
161 
162 std::size_t DynamicType::GetAlignment(
163     const TargetCharacteristics &targetCharacteristics) const {
164   if (category_ == TypeCategory::Derived) {
165     switch (GetDerivedTypeSpec().category()) {
166       SWITCH_COVERS_ALL_CASES
167     case semantics::DerivedTypeSpec::Category::DerivedType:
168       if (derived_ && derived_->scope()) {
169         return derived_->scope()->alignment().value_or(1);
170       }
171       break;
172     case semantics::DerivedTypeSpec::Category::IntrinsicVector:
173     case semantics::DerivedTypeSpec::Category::PairVector:
174     case semantics::DerivedTypeSpec::Category::QuadVector:
175       if (derived_ && derived_->scope()) {
176         return derived_->scope()->size();
177       } else {
178         common::die("Missing scope for Vector type.");
179       }
180     }
181   } else {
182     return targetCharacteristics.GetAlignment(category_, kind());
183   }
184   return 1; // needs to be after switch to dodge a bogus gcc warning
185 }
186 
187 std::optional<Expr<SubscriptInteger>> DynamicType::MeasureSizeInBytes(
188     FoldingContext &context, bool aligned,
189     std::optional<std::int64_t> charLength) const {
190   switch (category_) {
191   case TypeCategory::Integer:
192   case TypeCategory::Real:
193   case TypeCategory::Complex:
194   case TypeCategory::Logical:
195     return Expr<SubscriptInteger>{
196         context.targetCharacteristics().GetByteSize(category_, kind())};
197   case TypeCategory::Character:
198     if (auto len{charLength ? Expr<SubscriptInteger>{Constant<SubscriptInteger>{
199                                   *charLength}}
200                             : GetCharLength()}) {
201       return Fold(context,
202           Expr<SubscriptInteger>{
203               context.targetCharacteristics().GetByteSize(category_, kind())} *
204               std::move(*len));
205     }
206     break;
207   case TypeCategory::Derived:
208     if (!IsPolymorphic() && derived_ && derived_->scope()) {
209       auto size{derived_->scope()->size()};
210       auto align{aligned ? derived_->scope()->alignment().value_or(0) : 0};
211       auto alignedSize{align > 0 ? ((size + align - 1) / align) * align : size};
212       return Expr<SubscriptInteger>{
213           static_cast<ConstantSubscript>(alignedSize)};
214     }
215     break;
216   }
217   return std::nullopt;
218 }
219 
220 bool DynamicType::IsAssumedLengthCharacter() const {
221   return category_ == TypeCategory::Character && charLengthParamValue_ &&
222       charLengthParamValue_->isAssumed();
223 }
224 
225 bool DynamicType::IsNonConstantLengthCharacter() const {
226   if (category_ != TypeCategory::Character) {
227     return false;
228   } else if (knownLength()) {
229     return false;
230   } else if (!charLengthParamValue_) {
231     return true;
232   } else if (const auto &expr{charLengthParamValue_->GetExplicit()}) {
233     return !IsConstantExpr(*expr);
234   } else {
235     return true;
236   }
237 }
238 
239 bool DynamicType::IsTypelessIntrinsicArgument() const {
240   return category_ == TypeCategory::Integer && kind_ == TypelessKind;
241 }
242 
243 bool DynamicType::IsLengthlessIntrinsicType() const {
244   return common::IsNumericTypeCategory(category_) ||
245       category_ == TypeCategory::Logical;
246 }
247 
248 const semantics::DerivedTypeSpec *GetDerivedTypeSpec(
249     const std::optional<DynamicType> &type) {
250   return type ? GetDerivedTypeSpec(*type) : nullptr;
251 }
252 
253 const semantics::DerivedTypeSpec *GetDerivedTypeSpec(const DynamicType &type) {
254   if (type.category() == TypeCategory::Derived &&
255       !type.IsUnlimitedPolymorphic()) {
256     return &type.GetDerivedTypeSpec();
257   } else {
258     return nullptr;
259   }
260 }
261 
262 static const semantics::Symbol *FindParentComponent(
263     const semantics::DerivedTypeSpec &derived) {
264   const semantics::Symbol &typeSymbol{derived.typeSymbol()};
265   const semantics::Scope *scope{derived.scope()};
266   if (!scope) {
267     scope = typeSymbol.scope();
268   }
269   if (scope) {
270     const auto &dtDetails{typeSymbol.get<semantics::DerivedTypeDetails>()};
271     // TODO: Combine with semantics::DerivedTypeDetails::GetParentComponent
272     if (auto extends{dtDetails.GetParentComponentName()}) {
273       if (auto iter{scope->find(*extends)}; iter != scope->cend()) {
274         if (const semantics::Symbol & symbol{*iter->second};
275             symbol.test(semantics::Symbol::Flag::ParentComp)) {
276           return &symbol;
277         }
278       }
279     }
280   }
281   return nullptr;
282 }
283 
284 const semantics::DerivedTypeSpec *GetParentTypeSpec(
285     const semantics::DerivedTypeSpec &derived) {
286   if (const semantics::Symbol * parent{FindParentComponent(derived)}) {
287     return &parent->get<semantics::ObjectEntityDetails>()
288                 .type()
289                 ->derivedTypeSpec();
290   } else {
291     return nullptr;
292   }
293 }
294 
295 // Compares two derived type representations to see whether they both
296 // represent the "same type" in the sense of section 7.5.2.4.
297 using SetOfDerivedTypePairs =
298     std::set<std::pair<const semantics::DerivedTypeSpec *,
299         const semantics::DerivedTypeSpec *>>;
300 
301 static bool AreSameDerivedType(const semantics::DerivedTypeSpec &,
302     const semantics::DerivedTypeSpec &, bool ignoreTypeParameterValues,
303     bool ignoreLenParameters, SetOfDerivedTypePairs &inProgress);
304 
305 // F2023 7.5.3.2
306 static bool AreSameComponent(const semantics::Symbol &x,
307     const semantics::Symbol &y, SetOfDerivedTypePairs &inProgress) {
308   if (x.attrs() != y.attrs()) {
309     return false;
310   }
311   if (x.attrs().test(semantics::Attr::PRIVATE)) {
312     return false;
313   }
314   if (x.size() && y.size()) {
315     if (x.offset() != y.offset() || x.size() != y.size()) {
316       return false;
317     }
318   }
319   const auto *xObj{x.detailsIf<semantics::ObjectEntityDetails>()};
320   const auto *yObj{y.detailsIf<semantics::ObjectEntityDetails>()};
321   const auto *xProc{x.detailsIf<semantics::ProcEntityDetails>()};
322   const auto *yProc{y.detailsIf<semantics::ProcEntityDetails>()};
323   if (!xObj != !yObj || !xProc != !yProc) {
324     return false;
325   }
326   auto xType{DynamicType::From(x)};
327   auto yType{DynamicType::From(y)};
328   if (xType && yType) {
329     if (xType->category() == TypeCategory::Derived) {
330       if (yType->category() != TypeCategory::Derived ||
331           !xType->IsUnlimitedPolymorphic() !=
332               !yType->IsUnlimitedPolymorphic() ||
333           (!xType->IsUnlimitedPolymorphic() &&
334               !AreSameDerivedType(xType->GetDerivedTypeSpec(),
335                   yType->GetDerivedTypeSpec(), false, false, inProgress))) {
336         return false;
337       }
338     } else if (!xType->IsTkLenCompatibleWith(*yType)) {
339       return false;
340     }
341   } else if (xType || yType || !(xProc && yProc)) {
342     return false;
343   }
344   if (xProc) {
345     // TODO: compare argument types, &c.
346   }
347   return true;
348 }
349 
350 // TODO: These utilities were cloned out of Semantics to avoid a cyclic
351 // dependency and should be repackaged into then "namespace semantics"
352 // part of Evaluate/tools.cpp.
353 
354 static const semantics::Symbol *GetParentComponent(
355     const semantics::DerivedTypeDetails &details,
356     const semantics::Scope &scope) {
357   if (auto extends{details.GetParentComponentName()}) {
358     if (auto iter{scope.find(*extends)}; iter != scope.cend()) {
359       if (const Symbol & symbol{*iter->second};
360           symbol.test(semantics::Symbol::Flag::ParentComp)) {
361         return &symbol;
362       }
363     }
364   }
365   return nullptr;
366 }
367 
368 static const semantics::Symbol *GetParentComponent(
369     const semantics::Symbol *symbol, const semantics::Scope &scope) {
370   if (symbol) {
371     if (const auto *dtDetails{
372             symbol->detailsIf<semantics::DerivedTypeDetails>()}) {
373       return GetParentComponent(*dtDetails, scope);
374     }
375   }
376   return nullptr;
377 }
378 
379 static const semantics::DerivedTypeSpec *GetParentTypeSpec(
380     const semantics::Symbol *symbol, const semantics::Scope &scope) {
381   if (const Symbol * parentComponent{GetParentComponent(symbol, scope)}) {
382     return &parentComponent->get<semantics::ObjectEntityDetails>()
383                 .type()
384                 ->derivedTypeSpec();
385   } else {
386     return nullptr;
387   }
388 }
389 
390 static const semantics::Scope *GetDerivedTypeParent(
391     const semantics::Scope *scope) {
392   if (scope) {
393     CHECK(scope->IsDerivedType());
394     if (const auto *parent{GetParentTypeSpec(scope->GetSymbol(), *scope)}) {
395       return parent->scope();
396     }
397   }
398   return nullptr;
399 }
400 
401 static const semantics::Symbol *FindComponent(
402     const semantics::Scope *scope, parser::CharBlock name) {
403   if (!scope) {
404     return nullptr;
405   }
406   CHECK(scope->IsDerivedType());
407   auto found{scope->find(name)};
408   if (found != scope->end()) {
409     return &*found->second;
410   } else {
411     return FindComponent(GetDerivedTypeParent(scope), name);
412   }
413 }
414 
415 static bool AreTypeParamCompatible(const semantics::DerivedTypeSpec &x,
416     const semantics::DerivedTypeSpec &y, bool ignoreLenParameters) {
417   const auto *xScope{x.typeSymbol().scope()};
418   const auto *yScope{y.typeSymbol().scope()};
419   for (const auto &[paramName, value] : x.parameters()) {
420     const auto *yValue{y.FindParameter(paramName)};
421     if (!yValue) {
422       return false;
423     }
424     const auto *xParm{FindComponent(xScope, paramName)};
425     const auto *yParm{FindComponent(yScope, paramName)};
426     if (xParm && yParm) {
427       const auto *xTPD{xParm->detailsIf<semantics::TypeParamDetails>()};
428       const auto *yTPD{yParm->detailsIf<semantics::TypeParamDetails>()};
429       if (xTPD && yTPD) {
430         if (xTPD->attr() != yTPD->attr()) {
431           return false;
432         }
433         if (!ignoreLenParameters ||
434             xTPD->attr() != common::TypeParamAttr::Len) {
435           auto xExpr{value.GetExplicit()};
436           auto yExpr{yValue->GetExplicit()};
437           if (xExpr && yExpr) {
438             auto xVal{ToInt64(*xExpr)};
439             auto yVal{ToInt64(*yExpr)};
440             if (xVal && yVal && *xVal != *yVal) {
441               return false;
442             }
443           }
444         }
445       }
446     }
447   }
448   for (const auto &[paramName, _] : y.parameters()) {
449     if (!x.FindParameter(paramName)) {
450       return false; // y has more parameters than x
451     }
452   }
453   return true;
454 }
455 
456 // F2023 7.5.3.2
457 static bool AreSameDerivedType(const semantics::DerivedTypeSpec &x,
458     const semantics::DerivedTypeSpec &y, bool ignoreTypeParameterValues,
459     bool ignoreLenParameters, SetOfDerivedTypePairs &inProgress) {
460   if (&x == &y) {
461     return true;
462   }
463   if (!ignoreTypeParameterValues &&
464       !AreTypeParamCompatible(x, y, ignoreLenParameters)) {
465     return false;
466   }
467   const auto &xSymbol{x.typeSymbol().GetUltimate()};
468   const auto &ySymbol{y.typeSymbol().GetUltimate()};
469   if (xSymbol == ySymbol) {
470     return true;
471   }
472   if (xSymbol.name() != ySymbol.name()) {
473     return false;
474   }
475   auto thisQuery{std::make_pair(&x, &y)};
476   if (inProgress.find(thisQuery) != inProgress.end()) {
477     return true; // recursive use of types in components
478   }
479   inProgress.insert(thisQuery);
480   const auto &xDetails{xSymbol.get<semantics::DerivedTypeDetails>()};
481   const auto &yDetails{ySymbol.get<semantics::DerivedTypeDetails>()};
482   if (!(xDetails.sequence() && yDetails.sequence()) &&
483       !(xSymbol.attrs().test(semantics::Attr::BIND_C) &&
484           ySymbol.attrs().test(semantics::Attr::BIND_C))) {
485     // PGI does not enforce this requirement; all other Fortran
486     // compilers do with a hard error when violations are caught.
487     return false;
488   }
489   // Compare the component lists in their orders of declaration.
490   auto xEnd{xDetails.componentNames().cend()};
491   auto yComponentName{yDetails.componentNames().cbegin()};
492   auto yEnd{yDetails.componentNames().cend()};
493   for (auto xComponentName{xDetails.componentNames().cbegin()};
494        xComponentName != xEnd; ++xComponentName, ++yComponentName) {
495     if (yComponentName == yEnd || *xComponentName != *yComponentName ||
496         !xSymbol.scope() || !ySymbol.scope()) {
497       return false;
498     }
499     const auto xLookup{xSymbol.scope()->find(*xComponentName)};
500     const auto yLookup{ySymbol.scope()->find(*yComponentName)};
501     if (xLookup == xSymbol.scope()->end() ||
502         yLookup == ySymbol.scope()->end() ||
503         !AreSameComponent(*xLookup->second, *yLookup->second, inProgress)) {
504       return false;
505     }
506   }
507   return yComponentName == yEnd;
508 }
509 
510 bool AreSameDerivedType(
511     const semantics::DerivedTypeSpec &x, const semantics::DerivedTypeSpec &y) {
512   SetOfDerivedTypePairs inProgress;
513   return AreSameDerivedType(x, y, false, false, inProgress);
514 }
515 
516 static bool AreCompatibleDerivedTypes(const semantics::DerivedTypeSpec *x,
517     const semantics::DerivedTypeSpec *y, bool isPolymorphic,
518     bool ignoreTypeParameterValues, bool ignoreLenTypeParameters) {
519   if (!x || !y) {
520     return false;
521   } else {
522     SetOfDerivedTypePairs inProgress;
523     if (AreSameDerivedType(*x, *y, ignoreTypeParameterValues,
524             ignoreLenTypeParameters, inProgress)) {
525       return true;
526     } else {
527       return isPolymorphic &&
528           AreCompatibleDerivedTypes(x, GetParentTypeSpec(*y), true,
529               ignoreTypeParameterValues, ignoreLenTypeParameters);
530     }
531   }
532 }
533 
534 static bool AreCompatibleTypes(const DynamicType &x, const DynamicType &y,
535     bool ignoreTypeParameterValues, bool ignoreLengths) {
536   if (x.IsUnlimitedPolymorphic()) {
537     return true;
538   } else if (y.IsUnlimitedPolymorphic()) {
539     return false;
540   } else if (x.category() != y.category()) {
541     return false;
542   } else if (x.category() == TypeCategory::Character) {
543     const auto xLen{x.knownLength()};
544     const auto yLen{y.knownLength()};
545     return x.kind() == y.kind() &&
546         (ignoreLengths || !xLen || !yLen || *xLen == *yLen);
547   } else if (x.category() != TypeCategory::Derived) {
548     if (x.IsTypelessIntrinsicArgument()) {
549       return y.IsTypelessIntrinsicArgument();
550     } else {
551       return !y.IsTypelessIntrinsicArgument() && x.kind() == y.kind();
552     }
553   } else {
554     const auto *xdt{GetDerivedTypeSpec(x)};
555     const auto *ydt{GetDerivedTypeSpec(y)};
556     return AreCompatibleDerivedTypes(
557         xdt, ydt, x.IsPolymorphic(), ignoreTypeParameterValues, false);
558   }
559 }
560 
561 // See 7.3.2.3 (5) & 15.5.2.4
562 bool DynamicType::IsTkCompatibleWith(const DynamicType &that) const {
563   return AreCompatibleTypes(*this, that, false, true);
564 }
565 
566 bool DynamicType::IsTkCompatibleWith(
567     const DynamicType &that, common::IgnoreTKRSet ignoreTKR) const {
568   if (ignoreTKR.test(common::IgnoreTKR::Type) &&
569       (category() == TypeCategory::Derived ||
570           that.category() == TypeCategory::Derived ||
571           category() != that.category())) {
572     return true;
573   } else if (ignoreTKR.test(common::IgnoreTKR::Kind) &&
574       category() == that.category()) {
575     return true;
576   } else {
577     return AreCompatibleTypes(*this, that, false, true);
578   }
579 }
580 
581 bool DynamicType::IsTkLenCompatibleWith(const DynamicType &that) const {
582   return AreCompatibleTypes(*this, that, false, false);
583 }
584 
585 // 16.9.165
586 std::optional<bool> DynamicType::SameTypeAs(const DynamicType &that) const {
587   bool x{AreCompatibleTypes(*this, that, true, true)};
588   bool y{AreCompatibleTypes(that, *this, true, true)};
589   if (!x && !y) {
590     return false;
591   } else if (x && y && !IsPolymorphic() && !that.IsPolymorphic()) {
592     return true;
593   } else {
594     return std::nullopt;
595   }
596 }
597 
598 // 16.9.76
599 std::optional<bool> DynamicType::ExtendsTypeOf(const DynamicType &that) const {
600   if (IsUnlimitedPolymorphic() || that.IsUnlimitedPolymorphic()) {
601     return std::nullopt; // unknown
602   }
603   const auto *thisDts{evaluate::GetDerivedTypeSpec(*this)};
604   const auto *thatDts{evaluate::GetDerivedTypeSpec(that)};
605   if (!thisDts || !thatDts) {
606     return std::nullopt;
607   } else if (!AreCompatibleDerivedTypes(thatDts, thisDts, true, true, true)) {
608     // Note that I check *thisDts, not its parent, so that EXTENDS_TYPE_OF()
609     // is .true. when they are the same type.  This is technically
610     // an implementation-defined case in the standard, but every other
611     // compiler works this way.
612     if (IsPolymorphic() &&
613         AreCompatibleDerivedTypes(thisDts, thatDts, true, true, true)) {
614       // 'that' is *this or an extension of *this, and so runtime *this
615       // could be an extension of 'that'
616       return std::nullopt;
617     } else {
618       return false;
619     }
620   } else if (that.IsPolymorphic()) {
621     return std::nullopt; // unknown
622   } else {
623     return true;
624   }
625 }
626 
627 std::optional<DynamicType> DynamicType::From(
628     const semantics::DeclTypeSpec &type) {
629   if (const auto *intrinsic{type.AsIntrinsic()}) {
630     if (auto kind{ToInt64(intrinsic->kind())}) {
631       TypeCategory category{intrinsic->category()};
632       if (IsValidKindOfIntrinsicType(category, *kind)) {
633         if (category == TypeCategory::Character) {
634           const auto &charType{type.characterTypeSpec()};
635           return DynamicType{static_cast<int>(*kind), charType.length()};
636         } else {
637           return DynamicType{category, static_cast<int>(*kind)};
638         }
639       }
640     }
641   } else if (const auto *derived{type.AsDerived()}) {
642     return DynamicType{
643         *derived, type.category() == semantics::DeclTypeSpec::ClassDerived};
644   } else if (type.category() == semantics::DeclTypeSpec::ClassStar) {
645     return DynamicType::UnlimitedPolymorphic();
646   } else if (type.category() == semantics::DeclTypeSpec::TypeStar) {
647     return DynamicType::AssumedType();
648   } else {
649     common::die("DynamicType::From(DeclTypeSpec): failed");
650   }
651   return std::nullopt;
652 }
653 
654 std::optional<DynamicType> DynamicType::From(const semantics::Symbol &symbol) {
655   return From(symbol.GetType()); // Symbol -> DeclTypeSpec -> DynamicType
656 }
657 
658 DynamicType DynamicType::ResultTypeForMultiply(const DynamicType &that) const {
659   switch (category_) {
660   case TypeCategory::Integer:
661     switch (that.category_) {
662     case TypeCategory::Integer:
663       return DynamicType{TypeCategory::Integer, std::max(kind(), that.kind())};
664     case TypeCategory::Real:
665     case TypeCategory::Complex:
666       return that;
667     default:
668       CRASH_NO_CASE;
669     }
670     break;
671   case TypeCategory::Real:
672     switch (that.category_) {
673     case TypeCategory::Integer:
674       return *this;
675     case TypeCategory::Real:
676       return DynamicType{TypeCategory::Real, std::max(kind(), that.kind())};
677     case TypeCategory::Complex:
678       return DynamicType{TypeCategory::Complex, std::max(kind(), that.kind())};
679     default:
680       CRASH_NO_CASE;
681     }
682     break;
683   case TypeCategory::Complex:
684     switch (that.category_) {
685     case TypeCategory::Integer:
686       return *this;
687     case TypeCategory::Real:
688     case TypeCategory::Complex:
689       return DynamicType{TypeCategory::Complex, std::max(kind(), that.kind())};
690     default:
691       CRASH_NO_CASE;
692     }
693     break;
694   case TypeCategory::Logical:
695     switch (that.category_) {
696     case TypeCategory::Logical:
697       return DynamicType{TypeCategory::Logical, std::max(kind(), that.kind())};
698     default:
699       CRASH_NO_CASE;
700     }
701     break;
702   default:
703     CRASH_NO_CASE;
704   }
705   return *this;
706 }
707 
708 bool DynamicType::RequiresDescriptor() const {
709   return IsPolymorphic() || IsNonConstantLengthCharacter() ||
710       (derived_ && CountNonConstantLenParameters(*derived_) > 0);
711 }
712 
713 bool DynamicType::HasDeferredTypeParameter() const {
714   if (derived_) {
715     for (const auto &pair : derived_->parameters()) {
716       if (pair.second.isDeferred()) {
717         return true;
718       }
719     }
720   }
721   return charLengthParamValue_ && charLengthParamValue_->isDeferred();
722 }
723 
724 bool SomeKind<TypeCategory::Derived>::operator==(
725     const SomeKind<TypeCategory::Derived> &that) const {
726   return PointeeComparison(derivedTypeSpec_, that.derivedTypeSpec_);
727 }
728 
729 int SelectedCharKind(const std::string &s, int defaultKind) { // 16.9.168
730   auto lower{parser::ToLowerCaseLetters(s)};
731   auto n{lower.size()};
732   while (n > 0 && lower[0] == ' ') {
733     lower.erase(0, 1);
734     --n;
735   }
736   while (n > 0 && lower[n - 1] == ' ') {
737     lower.erase(--n, 1);
738   }
739   if (lower == "ascii") {
740     return 1;
741   } else if (lower == "ucs-2") {
742     return 2;
743   } else if (lower == "iso_10646" || lower == "ucs-4") {
744     return 4;
745   } else if (lower == "default") {
746     return defaultKind;
747   } else {
748     return -1;
749   }
750 }
751 
752 std::optional<DynamicType> ComparisonType(
753     const DynamicType &t1, const DynamicType &t2) {
754   switch (t1.category()) {
755   case TypeCategory::Integer:
756     switch (t2.category()) {
757     case TypeCategory::Integer:
758       return DynamicType{TypeCategory::Integer, std::max(t1.kind(), t2.kind())};
759     case TypeCategory::Real:
760     case TypeCategory::Complex:
761       return t2;
762     default:
763       return std::nullopt;
764     }
765   case TypeCategory::Real:
766     switch (t2.category()) {
767     case TypeCategory::Integer:
768       return t1;
769     case TypeCategory::Real:
770     case TypeCategory::Complex:
771       return DynamicType{t2.category(), std::max(t1.kind(), t2.kind())};
772     default:
773       return std::nullopt;
774     }
775   case TypeCategory::Complex:
776     switch (t2.category()) {
777     case TypeCategory::Integer:
778       return t1;
779     case TypeCategory::Real:
780     case TypeCategory::Complex:
781       return DynamicType{TypeCategory::Complex, std::max(t1.kind(), t2.kind())};
782     default:
783       return std::nullopt;
784     }
785   case TypeCategory::Character:
786     switch (t2.category()) {
787     case TypeCategory::Character:
788       return DynamicType{
789           TypeCategory::Character, std::max(t1.kind(), t2.kind())};
790     default:
791       return std::nullopt;
792     }
793   case TypeCategory::Logical:
794     switch (t2.category()) {
795     case TypeCategory::Logical:
796       return DynamicType{TypeCategory::Logical, LogicalResult::kind};
797     default:
798       return std::nullopt;
799     }
800   default:
801     return std::nullopt;
802   }
803 }
804 
805 bool IsInteroperableIntrinsicType(const DynamicType &type,
806     const common::LanguageFeatureControl *features, bool checkCharLength) {
807   switch (type.category()) {
808   case TypeCategory::Integer:
809     return true;
810   case TypeCategory::Real:
811   case TypeCategory::Complex:
812     return (features && features->IsEnabled(common::LanguageFeature::CUDA)) ||
813         type.kind() >= 4; // no short or half floats
814   case TypeCategory::Logical:
815     return type.kind() == 1; // C_BOOL
816   case TypeCategory::Character:
817     if (checkCharLength && type.knownLength().value_or(0) != 1) {
818       return false;
819     }
820     return type.kind() == 1 /* C_CHAR */;
821   default:
822     // Derived types are tested in Semantics/check-declarations.cpp
823     return false;
824   }
825 }
826 
827 bool IsCUDAIntrinsicType(const DynamicType &type) {
828   switch (type.category()) {
829   case TypeCategory::Integer:
830   case TypeCategory::Logical:
831     return type.kind() <= 8;
832   case TypeCategory::Real:
833     return type.kind() >= 2 && type.kind() <= 8;
834   case TypeCategory::Complex:
835     return type.kind() == 2 || type.kind() == 4 || type.kind() == 8;
836   case TypeCategory::Character:
837     return type.kind() == 1;
838   default:
839     // Derived types are tested in Semantics/check-declarations.cpp
840     return false;
841   }
842 }
843 
844 DynamicType DynamicType::DropNonConstantCharacterLength() const {
845   if (charLengthParamValue_ && charLengthParamValue_->isExplicit()) {
846     if (std::optional<std::int64_t> len{knownLength()}) {
847       return DynamicType(kind_, *len);
848     } else {
849       return DynamicType(category_, kind_);
850     }
851   }
852   return *this;
853 }
854 
855 } // namespace Fortran::evaluate
856