1 //===-- lib/Semantics/runtime-type-info.cpp ---------------------*- 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 #include "flang/Semantics/runtime-type-info.h"
10 #include "mod-file.h"
11 #include "flang/Evaluate/fold-designator.h"
12 #include "flang/Evaluate/fold.h"
13 #include "flang/Evaluate/tools.h"
14 #include "flang/Evaluate/type.h"
15 #include "flang/Semantics/scope.h"
16 #include "flang/Semantics/tools.h"
17 #include <functional>
18 #include <list>
19 #include <map>
20 #include <string>
21 
22 namespace Fortran::semantics {
23 
24 static int FindLenParameterIndex(
25     const SymbolVector &parameters, const Symbol &symbol) {
26   int lenIndex{0};
27   for (SymbolRef ref : parameters) {
28     if (&*ref == &symbol) {
29       return lenIndex;
30     }
31     if (ref->get<TypeParamDetails>().attr() == common::TypeParamAttr::Len) {
32       ++lenIndex;
33     }
34   }
35   DIE("Length type parameter not found in parameter order");
36   return -1;
37 }
38 
39 class RuntimeTableBuilder {
40 public:
41   RuntimeTableBuilder(SemanticsContext &, RuntimeDerivedTypeTables &);
42   void DescribeTypes(Scope &scope, bool inSchemata);
43 
44 private:
45   const Symbol *DescribeType(Scope &);
46   const Symbol &GetSchemaSymbol(const char *) const;
47   const DeclTypeSpec &GetSchema(const char *) const;
48   SomeExpr GetEnumValue(const char *) const;
49   Symbol &CreateObject(const std::string &, const DeclTypeSpec &, Scope &);
50   // The names of created symbols are saved in and owned by the
51   // RuntimeDerivedTypeTables instance returned by
52   // BuildRuntimeDerivedTypeTables() so that references to those names remain
53   // valid for lowering.
54   SourceName SaveObjectName(const std::string &);
55   SomeExpr SaveNameAsPointerTarget(Scope &, const std::string &);
56   const SymbolVector *GetTypeParameters(const Symbol &);
57   evaluate::StructureConstructor DescribeComponent(const Symbol &,
58       const ObjectEntityDetails &, Scope &, Scope &,
59       const std::string &distinctName, const SymbolVector *parameters);
60   evaluate::StructureConstructor DescribeComponent(
61       const Symbol &, const ProcEntityDetails &, Scope &);
62   bool InitializeDataPointer(evaluate::StructureConstructorValues &,
63       const Symbol &symbol, const ObjectEntityDetails &object, Scope &scope,
64       Scope &dtScope, const std::string &distinctName);
65   evaluate::StructureConstructor PackageIntValue(
66       const SomeExpr &genre, std::int64_t = 0) const;
67   SomeExpr PackageIntValueExpr(const SomeExpr &genre, std::int64_t = 0) const;
68   std::vector<const Symbol *> CollectBindings(const Scope &dtScope) const;
69   std::vector<evaluate::StructureConstructor> DescribeBindings(
70       const Scope &dtScope, Scope &);
71   void DescribeGeneric(
72       const GenericDetails &, std::map<int, evaluate::StructureConstructor> &);
73   void DescribeSpecialProc(std::map<int, evaluate::StructureConstructor> &,
74       const Symbol &specificOrBinding, bool isAssignment, bool isFinal,
75       std::optional<GenericKind::DefinedIo>);
76   void IncorporateDefinedIoGenericInterfaces(
77       std::map<int, evaluate::StructureConstructor> &, SourceName,
78       GenericKind::DefinedIo, const Scope *);
79 
80   // Instantiated for ParamValue and Bound
81   template <typename A>
82   evaluate::StructureConstructor GetValue(
83       const A &x, const SymbolVector *parameters) {
84     if (x.isExplicit()) {
85       return GetValue(x.GetExplicit(), parameters);
86     } else {
87       return PackageIntValue(deferredEnum_);
88     }
89   }
90 
91   // Specialization for optional<Expr<SomeInteger and SubscriptInteger>>
92   template <typename T>
93   evaluate::StructureConstructor GetValue(
94       const std::optional<evaluate::Expr<T>> &expr,
95       const SymbolVector *parameters) {
96     if (auto constValue{evaluate::ToInt64(expr)}) {
97       return PackageIntValue(explicitEnum_, *constValue);
98     }
99     if (expr) {
100       if (parameters) {
101         if (const Symbol * lenParam{evaluate::ExtractBareLenParameter(*expr)}) {
102           return PackageIntValue(
103               lenParameterEnum_, FindLenParameterIndex(*parameters, *lenParam));
104         }
105       }
106       context_.Say(location_,
107           "Specification expression '%s' is neither constant nor a length "
108           "type parameter"_err_en_US,
109           expr->AsFortran());
110     }
111     return PackageIntValue(deferredEnum_);
112   }
113 
114   SemanticsContext &context_;
115   RuntimeDerivedTypeTables &tables_;
116   std::map<const Symbol *, SymbolVector> orderedTypeParameters_;
117   int anonymousTypes_{0};
118 
119   const DeclTypeSpec &derivedTypeSchema_; // TYPE(DerivedType)
120   const DeclTypeSpec &componentSchema_; // TYPE(Component)
121   const DeclTypeSpec &procPtrSchema_; // TYPE(ProcPtrComponent)
122   const DeclTypeSpec &valueSchema_; // TYPE(Value)
123   const DeclTypeSpec &bindingSchema_; // TYPE(Binding)
124   const DeclTypeSpec &specialSchema_; // TYPE(SpecialBinding)
125   SomeExpr deferredEnum_; // Value::Genre::Deferred
126   SomeExpr explicitEnum_; // Value::Genre::Explicit
127   SomeExpr lenParameterEnum_; // Value::Genre::LenParameter
128   SomeExpr scalarAssignmentEnum_; // SpecialBinding::Which::ScalarAssignment
129   SomeExpr
130       elementalAssignmentEnum_; // SpecialBinding::Which::ElementalAssignment
131   SomeExpr readFormattedEnum_; // SpecialBinding::Which::ReadFormatted
132   SomeExpr readUnformattedEnum_; // SpecialBinding::Which::ReadUnformatted
133   SomeExpr writeFormattedEnum_; // SpecialBinding::Which::WriteFormatted
134   SomeExpr writeUnformattedEnum_; // SpecialBinding::Which::WriteUnformatted
135   SomeExpr elementalFinalEnum_; // SpecialBinding::Which::ElementalFinal
136   SomeExpr assumedRankFinalEnum_; // SpecialBinding::Which::AssumedRankFinal
137   SomeExpr scalarFinalEnum_; // SpecialBinding::Which::ScalarFinal
138   parser::CharBlock location_;
139   std::set<const Scope *> ignoreScopes_;
140 };
141 
142 RuntimeTableBuilder::RuntimeTableBuilder(
143     SemanticsContext &c, RuntimeDerivedTypeTables &t)
144     : context_{c}, tables_{t}, derivedTypeSchema_{GetSchema("derivedtype")},
145       componentSchema_{GetSchema("component")}, procPtrSchema_{GetSchema(
146                                                     "procptrcomponent")},
147       valueSchema_{GetSchema("value")}, bindingSchema_{GetSchema("binding")},
148       specialSchema_{GetSchema("specialbinding")}, deferredEnum_{GetEnumValue(
149                                                        "deferred")},
150       explicitEnum_{GetEnumValue("explicit")}, lenParameterEnum_{GetEnumValue(
151                                                    "lenparameter")},
152       scalarAssignmentEnum_{GetEnumValue("scalarassignment")},
153       elementalAssignmentEnum_{GetEnumValue("elementalassignment")},
154       readFormattedEnum_{GetEnumValue("readformatted")},
155       readUnformattedEnum_{GetEnumValue("readunformatted")},
156       writeFormattedEnum_{GetEnumValue("writeformatted")},
157       writeUnformattedEnum_{GetEnumValue("writeunformatted")},
158       elementalFinalEnum_{GetEnumValue("elementalfinal")},
159       assumedRankFinalEnum_{GetEnumValue("assumedrankfinal")},
160       scalarFinalEnum_{GetEnumValue("scalarfinal")} {
161   ignoreScopes_.insert(tables_.schemata);
162 }
163 
164 void RuntimeTableBuilder::DescribeTypes(Scope &scope, bool inSchemata) {
165   inSchemata |= ignoreScopes_.find(&scope) != ignoreScopes_.end();
166   if (scope.IsDerivedType()) {
167     if (!inSchemata) { // don't loop trying to describe a schema
168       DescribeType(scope);
169     }
170   } else {
171     scope.InstantiateDerivedTypes();
172   }
173   for (Scope &child : scope.children()) {
174     DescribeTypes(child, inSchemata);
175   }
176 }
177 
178 // Returns derived type instantiation's parameters in declaration order
179 const SymbolVector *RuntimeTableBuilder::GetTypeParameters(
180     const Symbol &symbol) {
181   auto iter{orderedTypeParameters_.find(&symbol)};
182   if (iter != orderedTypeParameters_.end()) {
183     return &iter->second;
184   } else {
185     return &orderedTypeParameters_
186                 .emplace(&symbol, OrderParameterDeclarations(symbol))
187                 .first->second;
188   }
189 }
190 
191 static Scope &GetContainingNonDerivedScope(Scope &scope) {
192   Scope *p{&scope};
193   while (p->IsDerivedType()) {
194     p = &p->parent();
195   }
196   return *p;
197 }
198 
199 static const Symbol &GetSchemaField(
200     const DerivedTypeSpec &derived, const std::string &name) {
201   const Scope &scope{
202       DEREF(derived.scope() ? derived.scope() : derived.typeSymbol().scope())};
203   auto iter{scope.find(SourceName(name))};
204   CHECK(iter != scope.end());
205   return *iter->second;
206 }
207 
208 static const Symbol &GetSchemaField(
209     const DeclTypeSpec &derived, const std::string &name) {
210   return GetSchemaField(DEREF(derived.AsDerived()), name);
211 }
212 
213 static evaluate::StructureConstructorValues &AddValue(
214     evaluate::StructureConstructorValues &values, const DeclTypeSpec &spec,
215     const std::string &name, SomeExpr &&x) {
216   values.emplace(GetSchemaField(spec, name), std::move(x));
217   return values;
218 }
219 
220 static evaluate::StructureConstructorValues &AddValue(
221     evaluate::StructureConstructorValues &values, const DeclTypeSpec &spec,
222     const std::string &name, const SomeExpr &x) {
223   values.emplace(GetSchemaField(spec, name), x);
224   return values;
225 }
226 
227 static SomeExpr IntToExpr(std::int64_t n) {
228   return evaluate::AsGenericExpr(evaluate::ExtentExpr{n});
229 }
230 
231 static evaluate::StructureConstructor Structure(
232     const DeclTypeSpec &spec, evaluate::StructureConstructorValues &&values) {
233   return {DEREF(spec.AsDerived()), std::move(values)};
234 }
235 
236 static SomeExpr StructureExpr(evaluate::StructureConstructor &&x) {
237   return SomeExpr{evaluate::Expr<evaluate::SomeDerived>{std::move(x)}};
238 }
239 
240 static int GetIntegerKind(const Symbol &symbol) {
241   auto dyType{evaluate::DynamicType::From(symbol)};
242   CHECK(dyType && dyType->category() == TypeCategory::Integer);
243   return dyType->kind();
244 }
245 
246 // Save a rank-1 array constant of some numeric type as an
247 // initialized data object in a scope.
248 template <typename T>
249 static SomeExpr SaveNumericPointerTarget(
250     Scope &scope, SourceName name, std::vector<typename T::Scalar> &&x) {
251   if (x.empty()) {
252     return SomeExpr{evaluate::NullPointer{}};
253   } else {
254     ObjectEntityDetails object;
255     if (const auto *spec{scope.FindType(
256             DeclTypeSpec{NumericTypeSpec{T::category, KindExpr{T::kind}}})}) {
257       object.set_type(*spec);
258     } else {
259       object.set_type(scope.MakeNumericType(T::category, KindExpr{T::kind}));
260     }
261     auto elements{static_cast<evaluate::ConstantSubscript>(x.size())};
262     ArraySpec arraySpec;
263     arraySpec.push_back(ShapeSpec::MakeExplicit(Bound{0}, Bound{elements - 1}));
264     object.set_shape(arraySpec);
265     object.set_init(evaluate::AsGenericExpr(evaluate::Constant<T>{
266         std::move(x), evaluate::ConstantSubscripts{elements}}));
267     Symbol &symbol{*scope
268                         .try_emplace(name, Attrs{Attr::TARGET, Attr::SAVE},
269                             std::move(object))
270                         .first->second};
271     symbol.set(Symbol::Flag::CompilerCreated);
272     return evaluate::AsGenericExpr(
273         evaluate::Expr<T>{evaluate::Designator<T>{symbol}});
274   }
275 }
276 
277 // Save an arbitrarily shaped array constant of some derived type
278 // as an initialized data object in a scope.
279 static SomeExpr SaveDerivedPointerTarget(Scope &scope, SourceName name,
280     std::vector<evaluate::StructureConstructor> &&x,
281     evaluate::ConstantSubscripts &&shape) {
282   if (x.empty()) {
283     return SomeExpr{evaluate::NullPointer{}};
284   } else {
285     const auto &derivedType{x.front().GetType().GetDerivedTypeSpec()};
286     ObjectEntityDetails object;
287     DeclTypeSpec typeSpec{DeclTypeSpec::TypeDerived, derivedType};
288     if (const DeclTypeSpec * spec{scope.FindType(typeSpec)}) {
289       object.set_type(*spec);
290     } else {
291       object.set_type(scope.MakeDerivedType(
292           DeclTypeSpec::TypeDerived, common::Clone(derivedType)));
293     }
294     if (!shape.empty()) {
295       ArraySpec arraySpec;
296       for (auto n : shape) {
297         arraySpec.push_back(ShapeSpec::MakeExplicit(Bound{0}, Bound{n - 1}));
298       }
299       object.set_shape(arraySpec);
300     }
301     object.set_init(
302         evaluate::AsGenericExpr(evaluate::Constant<evaluate::SomeDerived>{
303             derivedType, std::move(x), std::move(shape)}));
304     Symbol &symbol{*scope
305                         .try_emplace(name, Attrs{Attr::TARGET, Attr::SAVE},
306                             std::move(object))
307                         .first->second};
308     symbol.set(Symbol::Flag::CompilerCreated);
309     return evaluate::AsGenericExpr(
310         evaluate::Designator<evaluate::SomeDerived>{symbol});
311   }
312 }
313 
314 static SomeExpr SaveObjectInit(
315     Scope &scope, SourceName name, const ObjectEntityDetails &object) {
316   Symbol &symbol{*scope
317                       .try_emplace(name, Attrs{Attr::TARGET, Attr::SAVE},
318                           ObjectEntityDetails{object})
319                       .first->second};
320   CHECK(symbol.get<ObjectEntityDetails>().init().has_value());
321   symbol.set(Symbol::Flag::CompilerCreated);
322   return evaluate::AsGenericExpr(
323       evaluate::Designator<evaluate::SomeDerived>{symbol});
324 }
325 
326 template <int KIND> static SomeExpr IntExpr(std::int64_t n) {
327   return evaluate::AsGenericExpr(
328       evaluate::Constant<evaluate::Type<TypeCategory::Integer, KIND>>{n});
329 }
330 
331 const Symbol *RuntimeTableBuilder::DescribeType(Scope &dtScope) {
332   if (const Symbol * info{dtScope.runtimeDerivedTypeDescription()}) {
333     return info;
334   }
335   const DerivedTypeSpec *derivedTypeSpec{dtScope.derivedTypeSpec()};
336   if (!derivedTypeSpec && !dtScope.IsParameterizedDerivedType() &&
337       dtScope.symbol()) {
338     // This derived type was declared (obviously, there's a Scope) but never
339     // used in this compilation (no instantiated DerivedTypeSpec points here).
340     // Create a DerivedTypeSpec now for it so that ComponentIterator
341     // will work. This covers the case of a derived type that's declared in
342     // a module but used only by clients and submodules, enabling the
343     // run-time "no initialization needed here" flag to work.
344     DerivedTypeSpec derived{dtScope.symbol()->name(), *dtScope.symbol()};
345     DeclTypeSpec &decl{
346         dtScope.MakeDerivedType(DeclTypeSpec::TypeDerived, std::move(derived))};
347     derivedTypeSpec = &decl.derivedTypeSpec();
348   }
349   const Symbol *dtSymbol{
350       derivedTypeSpec ? &derivedTypeSpec->typeSymbol() : dtScope.symbol()};
351   if (!dtSymbol) {
352     return nullptr;
353   }
354   auto locationRestorer{common::ScopedSet(location_, dtSymbol->name())};
355   // Check for an existing description that can be imported from a USE'd module
356   std::string typeName{dtSymbol->name().ToString()};
357   if (typeName.empty() ||
358       (typeName.front() == '.' && !context_.IsTempName(typeName))) {
359     return nullptr;
360   }
361   std::string distinctName{typeName};
362   if (&dtScope != dtSymbol->scope()) {
363     distinctName += "."s + std::to_string(anonymousTypes_++);
364   }
365   std::string dtDescName{".dt."s + distinctName};
366   Scope &scope{GetContainingNonDerivedScope(dtScope)};
367   if (distinctName == typeName && scope.IsModule()) {
368     if (const Symbol * description{scope.FindSymbol(SourceName{dtDescName})}) {
369       dtScope.set_runtimeDerivedTypeDescription(*description);
370       return description;
371     }
372   }
373   // Create a new description object before populating it so that mutual
374   // references will work as pointer targets.
375   Symbol &dtObject{CreateObject(dtDescName, derivedTypeSchema_, scope)};
376   dtScope.set_runtimeDerivedTypeDescription(dtObject);
377   evaluate::StructureConstructorValues dtValues;
378   AddValue(dtValues, derivedTypeSchema_, "name"s,
379       SaveNameAsPointerTarget(scope, typeName));
380   bool isPDTdefinition{
381       !derivedTypeSpec && dtScope.IsParameterizedDerivedType()};
382   if (!isPDTdefinition) {
383     auto sizeInBytes{static_cast<common::ConstantSubscript>(dtScope.size())};
384     if (auto alignment{dtScope.alignment().value_or(0)}) {
385       sizeInBytes += alignment - 1;
386       sizeInBytes /= alignment;
387       sizeInBytes *= alignment;
388     }
389     AddValue(
390         dtValues, derivedTypeSchema_, "sizeinbytes"s, IntToExpr(sizeInBytes));
391   }
392   bool isPDTinstantiation{derivedTypeSpec && &dtScope != dtSymbol->scope()};
393   if (isPDTinstantiation) {
394     // is PDT instantiation
395     const Symbol *uninstDescObject{
396         DescribeType(DEREF(const_cast<Scope *>(dtSymbol->scope())))};
397     AddValue(dtValues, derivedTypeSchema_, "uninstantiated"s,
398         evaluate::AsGenericExpr(evaluate::Expr<evaluate::SomeDerived>{
399             evaluate::Designator<evaluate::SomeDerived>{
400                 DEREF(uninstDescObject)}}));
401   } else {
402     AddValue(dtValues, derivedTypeSchema_, "uninstantiated"s,
403         SomeExpr{evaluate::NullPointer{}});
404   }
405   using Int8 = evaluate::Type<TypeCategory::Integer, 8>;
406   using Int1 = evaluate::Type<TypeCategory::Integer, 1>;
407   std::vector<Int8::Scalar> kinds;
408   std::vector<Int1::Scalar> lenKinds;
409   const SymbolVector *parameters{GetTypeParameters(*dtSymbol)};
410   if (parameters) {
411     // Package the derived type's parameters in declaration order for
412     // each category of parameter.  KIND= type parameters are described
413     // by their instantiated (or default) values, while LEN= type
414     // parameters are described by their INTEGER kinds.
415     for (SymbolRef ref : *parameters) {
416       const auto &tpd{ref->get<TypeParamDetails>()};
417       if (tpd.attr() == common::TypeParamAttr::Kind) {
418         auto value{evaluate::ToInt64(tpd.init()).value_or(0)};
419         if (derivedTypeSpec) {
420           if (const auto *pv{derivedTypeSpec->FindParameter(ref->name())}) {
421             if (pv->GetExplicit()) {
422               if (auto instantiatedValue{
423                       evaluate::ToInt64(*pv->GetExplicit())}) {
424                 value = *instantiatedValue;
425               }
426             }
427           }
428         }
429         kinds.emplace_back(value);
430       } else { // LEN= parameter
431         lenKinds.emplace_back(GetIntegerKind(*ref));
432       }
433     }
434   }
435   AddValue(dtValues, derivedTypeSchema_, "kindparameter"s,
436       SaveNumericPointerTarget<Int8>(
437           scope, SaveObjectName(".kp."s + distinctName), std::move(kinds)));
438   AddValue(dtValues, derivedTypeSchema_, "lenparameterkind"s,
439       SaveNumericPointerTarget<Int1>(
440           scope, SaveObjectName(".lpk."s + distinctName), std::move(lenKinds)));
441   // Traverse the components of the derived type
442   if (!isPDTdefinition) {
443     std::vector<const Symbol *> dataComponentSymbols;
444     std::vector<evaluate::StructureConstructor> procPtrComponents;
445     std::map<int, evaluate::StructureConstructor> specials;
446     for (const auto &pair : dtScope) {
447       const Symbol &symbol{*pair.second};
448       auto locationRestorer{common::ScopedSet(location_, symbol.name())};
449       std::visit(
450           common::visitors{
451               [&](const TypeParamDetails &) {
452                 // already handled above in declaration order
453               },
454               [&](const ObjectEntityDetails &) {
455                 dataComponentSymbols.push_back(&symbol);
456               },
457               [&](const ProcEntityDetails &proc) {
458                 if (IsProcedurePointer(symbol)) {
459                   procPtrComponents.emplace_back(
460                       DescribeComponent(symbol, proc, scope));
461                 }
462               },
463               [&](const ProcBindingDetails &) { // handled in a later pass
464               },
465               [&](const GenericDetails &generic) {
466                 DescribeGeneric(generic, specials);
467               },
468               [&](const auto &) {
469                 common::die(
470                     "unexpected details on symbol '%s' in derived type scope",
471                     symbol.name().ToString().c_str());
472               },
473           },
474           symbol.details());
475     }
476     // Sort the data component symbols by offset before emitting them
477     std::sort(dataComponentSymbols.begin(), dataComponentSymbols.end(),
478         [](const Symbol *x, const Symbol *y) {
479           return x->offset() < y->offset();
480         });
481     std::vector<evaluate::StructureConstructor> dataComponents;
482     for (const Symbol *symbol : dataComponentSymbols) {
483       auto locationRestorer{common::ScopedSet(location_, symbol->name())};
484       dataComponents.emplace_back(
485           DescribeComponent(*symbol, symbol->get<ObjectEntityDetails>(), scope,
486               dtScope, distinctName, parameters));
487     }
488     AddValue(dtValues, derivedTypeSchema_, "component"s,
489         SaveDerivedPointerTarget(scope, SaveObjectName(".c."s + distinctName),
490             std::move(dataComponents),
491             evaluate::ConstantSubscripts{
492                 static_cast<evaluate::ConstantSubscript>(
493                     dataComponents.size())}));
494     AddValue(dtValues, derivedTypeSchema_, "procptr"s,
495         SaveDerivedPointerTarget(scope, SaveObjectName(".p."s + distinctName),
496             std::move(procPtrComponents),
497             evaluate::ConstantSubscripts{
498                 static_cast<evaluate::ConstantSubscript>(
499                     procPtrComponents.size())}));
500     // Compile the "vtable" of type-bound procedure bindings
501     std::vector<evaluate::StructureConstructor> bindings{
502         DescribeBindings(dtScope, scope)};
503     AddValue(dtValues, derivedTypeSchema_, "binding"s,
504         SaveDerivedPointerTarget(scope, SaveObjectName(".v."s + distinctName),
505             std::move(bindings),
506             evaluate::ConstantSubscripts{
507                 static_cast<evaluate::ConstantSubscript>(bindings.size())}));
508     // Describe "special" bindings to defined assignments, FINAL subroutines,
509     // and user-defined derived type I/O subroutines.
510     const DerivedTypeDetails &dtDetails{dtSymbol->get<DerivedTypeDetails>()};
511     for (const auto &pair : dtDetails.finals()) {
512       DescribeSpecialProc(
513           specials, *pair.second, false /*!isAssignment*/, true, std::nullopt);
514     }
515     IncorporateDefinedIoGenericInterfaces(specials,
516         SourceName{"read(formatted)", 15},
517         GenericKind::DefinedIo::ReadFormatted, &scope);
518     IncorporateDefinedIoGenericInterfaces(specials,
519         SourceName{"read(unformatted)", 17},
520         GenericKind::DefinedIo::ReadUnformatted, &scope);
521     IncorporateDefinedIoGenericInterfaces(specials,
522         SourceName{"write(formatted)", 16},
523         GenericKind::DefinedIo::WriteFormatted, &scope);
524     IncorporateDefinedIoGenericInterfaces(specials,
525         SourceName{"write(unformatted)", 18},
526         GenericKind::DefinedIo::WriteUnformatted, &scope);
527     // Pack the special procedure bindings in ascending order of their "which"
528     // code values, and compile a little-endian bit-set of those codes for
529     // use in O(1) look-up at run time.
530     std::vector<evaluate::StructureConstructor> sortedSpecials;
531     std::uint32_t specialBitSet{0};
532     for (auto &pair : specials) {
533       auto bit{std::uint32_t{1} << pair.first};
534       CHECK(!(specialBitSet & bit));
535       specialBitSet |= bit;
536       sortedSpecials.emplace_back(std::move(pair.second));
537     }
538     AddValue(dtValues, derivedTypeSchema_, "special"s,
539         SaveDerivedPointerTarget(scope, SaveObjectName(".s."s + distinctName),
540             std::move(sortedSpecials),
541             evaluate::ConstantSubscripts{
542                 static_cast<evaluate::ConstantSubscript>(specials.size())}));
543     AddValue(dtValues, derivedTypeSchema_, "specialbitset"s,
544         IntExpr<4>(specialBitSet));
545     // Note the presence/absence of a parent component
546     AddValue(dtValues, derivedTypeSchema_, "hasparent"s,
547         IntExpr<1>(dtScope.GetDerivedTypeParent() != nullptr));
548     // To avoid wasting run time attempting to initialize derived type
549     // instances without any initialized components, analyze the type
550     // and set a flag if there's nothing to do for it at run time.
551     AddValue(dtValues, derivedTypeSchema_, "noinitializationneeded"s,
552         IntExpr<1>(
553             derivedTypeSpec && !derivedTypeSpec->HasDefaultInitialization()));
554     // Similarly, a flag to short-circuit destruction when not needed.
555     AddValue(dtValues, derivedTypeSchema_, "nodestructionneeded"s,
556         IntExpr<1>(derivedTypeSpec && !derivedTypeSpec->HasDestruction()));
557     // Similarly, a flag to short-circuit finalization when not needed.
558     AddValue(dtValues, derivedTypeSchema_, "nofinalizationneeded"s,
559         IntExpr<1>(derivedTypeSpec && !IsFinalizable(*derivedTypeSpec)));
560   }
561   dtObject.get<ObjectEntityDetails>().set_init(MaybeExpr{
562       StructureExpr(Structure(derivedTypeSchema_, std::move(dtValues)))});
563   return &dtObject;
564 }
565 
566 static const Symbol &GetSymbol(const Scope &schemata, SourceName name) {
567   auto iter{schemata.find(name)};
568   CHECK(iter != schemata.end());
569   const Symbol &symbol{*iter->second};
570   return symbol;
571 }
572 
573 const Symbol &RuntimeTableBuilder::GetSchemaSymbol(const char *name) const {
574   return GetSymbol(
575       DEREF(tables_.schemata), SourceName{name, std::strlen(name)});
576 }
577 
578 const DeclTypeSpec &RuntimeTableBuilder::GetSchema(
579     const char *schemaName) const {
580   Scope &schemata{DEREF(tables_.schemata)};
581   SourceName name{schemaName, std::strlen(schemaName)};
582   const Symbol &symbol{GetSymbol(schemata, name)};
583   CHECK(symbol.has<DerivedTypeDetails>());
584   CHECK(symbol.scope());
585   CHECK(symbol.scope()->IsDerivedType());
586   const DeclTypeSpec *spec{nullptr};
587   if (symbol.scope()->derivedTypeSpec()) {
588     DeclTypeSpec typeSpec{
589         DeclTypeSpec::TypeDerived, *symbol.scope()->derivedTypeSpec()};
590     spec = schemata.FindType(typeSpec);
591   }
592   if (!spec) {
593     DeclTypeSpec typeSpec{
594         DeclTypeSpec::TypeDerived, DerivedTypeSpec{name, symbol}};
595     spec = schemata.FindType(typeSpec);
596   }
597   if (!spec) {
598     spec = &schemata.MakeDerivedType(
599         DeclTypeSpec::TypeDerived, DerivedTypeSpec{name, symbol});
600   }
601   CHECK(spec->AsDerived());
602   return *spec;
603 }
604 
605 SomeExpr RuntimeTableBuilder::GetEnumValue(const char *name) const {
606   const Symbol &symbol{GetSchemaSymbol(name)};
607   auto value{evaluate::ToInt64(symbol.get<ObjectEntityDetails>().init())};
608   CHECK(value.has_value());
609   return IntExpr<1>(*value);
610 }
611 
612 Symbol &RuntimeTableBuilder::CreateObject(
613     const std::string &name, const DeclTypeSpec &type, Scope &scope) {
614   ObjectEntityDetails object;
615   object.set_type(type);
616   auto pair{scope.try_emplace(SaveObjectName(name),
617       Attrs{Attr::TARGET, Attr::SAVE}, std::move(object))};
618   CHECK(pair.second);
619   Symbol &result{*pair.first->second};
620   result.set(Symbol::Flag::CompilerCreated);
621   return result;
622 }
623 
624 SourceName RuntimeTableBuilder::SaveObjectName(const std::string &name) {
625   return *tables_.names.insert(name).first;
626 }
627 
628 SomeExpr RuntimeTableBuilder::SaveNameAsPointerTarget(
629     Scope &scope, const std::string &name) {
630   CHECK(!name.empty());
631   CHECK(name.front() != '.' || context_.IsTempName(name));
632   ObjectEntityDetails object;
633   auto len{static_cast<common::ConstantSubscript>(name.size())};
634   if (const auto *spec{scope.FindType(DeclTypeSpec{CharacterTypeSpec{
635           ParamValue{len, common::TypeParamAttr::Len}, KindExpr{1}}})}) {
636     object.set_type(*spec);
637   } else {
638     object.set_type(scope.MakeCharacterType(
639         ParamValue{len, common::TypeParamAttr::Len}, KindExpr{1}));
640   }
641   using evaluate::Ascii;
642   using AsciiExpr = evaluate::Expr<Ascii>;
643   object.set_init(evaluate::AsGenericExpr(AsciiExpr{name}));
644   Symbol &symbol{*scope
645                       .try_emplace(SaveObjectName(".n."s + name),
646                           Attrs{Attr::TARGET, Attr::SAVE}, std::move(object))
647                       .first->second};
648   symbol.set(Symbol::Flag::CompilerCreated);
649   return evaluate::AsGenericExpr(
650       AsciiExpr{evaluate::Designator<Ascii>{symbol}});
651 }
652 
653 evaluate::StructureConstructor RuntimeTableBuilder::DescribeComponent(
654     const Symbol &symbol, const ObjectEntityDetails &object, Scope &scope,
655     Scope &dtScope, const std::string &distinctName,
656     const SymbolVector *parameters) {
657   evaluate::StructureConstructorValues values;
658   auto &foldingContext{context_.foldingContext()};
659   auto typeAndShape{evaluate::characteristics::TypeAndShape::Characterize(
660       symbol, foldingContext)};
661   CHECK(typeAndShape.has_value());
662   auto dyType{typeAndShape->type()};
663   const auto &shape{typeAndShape->shape()};
664   AddValue(values, componentSchema_, "name"s,
665       SaveNameAsPointerTarget(scope, symbol.name().ToString()));
666   AddValue(values, componentSchema_, "category"s,
667       IntExpr<1>(static_cast<int>(dyType.category())));
668   if (dyType.IsUnlimitedPolymorphic() ||
669       dyType.category() == TypeCategory::Derived) {
670     AddValue(values, componentSchema_, "kind"s, IntExpr<1>(0));
671   } else {
672     AddValue(values, componentSchema_, "kind"s, IntExpr<1>(dyType.kind()));
673   }
674   AddValue(values, componentSchema_, "offset"s, IntExpr<8>(symbol.offset()));
675   // CHARACTER length
676   auto len{typeAndShape->LEN()};
677   if (const semantics::DerivedTypeSpec *
678       pdtInstance{dtScope.derivedTypeSpec()}) {
679     auto restorer{foldingContext.WithPDTInstance(*pdtInstance)};
680     len = Fold(foldingContext, std::move(len));
681   }
682   if (dyType.category() == TypeCategory::Character && len) {
683     // Ignore IDIM(x) (represented as MAX(0, x))
684     if (const auto *clamped{evaluate::UnwrapExpr<
685             evaluate::Extremum<evaluate::SubscriptInteger>>(*len)}) {
686       if (clamped->ordering == evaluate::Ordering::Greater &&
687           clamped->left() == evaluate::Expr<evaluate::SubscriptInteger>{0}) {
688         len = clamped->right();
689       }
690     }
691     AddValue(values, componentSchema_, "characterlen"s,
692         evaluate::AsGenericExpr(GetValue(len, parameters)));
693   } else {
694     AddValue(values, componentSchema_, "characterlen"s,
695         PackageIntValueExpr(deferredEnum_));
696   }
697   // Describe component's derived type
698   std::vector<evaluate::StructureConstructor> lenParams;
699   if (dyType.category() == TypeCategory::Derived &&
700       !dyType.IsUnlimitedPolymorphic()) {
701     const DerivedTypeSpec &spec{dyType.GetDerivedTypeSpec()};
702     Scope *derivedScope{const_cast<Scope *>(
703         spec.scope() ? spec.scope() : spec.typeSymbol().scope())};
704     const Symbol *derivedDescription{DescribeType(DEREF(derivedScope))};
705     AddValue(values, componentSchema_, "derived"s,
706         evaluate::AsGenericExpr(evaluate::Expr<evaluate::SomeDerived>{
707             evaluate::Designator<evaluate::SomeDerived>{
708                 DEREF(derivedDescription)}}));
709     // Package values of LEN parameters, if any
710     if (const SymbolVector * specParams{GetTypeParameters(spec.typeSymbol())}) {
711       for (SymbolRef ref : *specParams) {
712         const auto &tpd{ref->get<TypeParamDetails>()};
713         if (tpd.attr() == common::TypeParamAttr::Len) {
714           if (const ParamValue * paramValue{spec.FindParameter(ref->name())}) {
715             lenParams.emplace_back(GetValue(*paramValue, parameters));
716           } else {
717             lenParams.emplace_back(GetValue(tpd.init(), parameters));
718           }
719         }
720       }
721     }
722   } else {
723     // Subtle: a category of Derived with a null derived type pointer
724     // signifies CLASS(*)
725     AddValue(values, componentSchema_, "derived"s,
726         SomeExpr{evaluate::NullPointer{}});
727   }
728   // LEN type parameter values for the component's type
729   if (!lenParams.empty()) {
730     AddValue(values, componentSchema_, "lenvalue"s,
731         SaveDerivedPointerTarget(scope,
732             SaveObjectName(
733                 ".lv."s + distinctName + "."s + symbol.name().ToString()),
734             std::move(lenParams),
735             evaluate::ConstantSubscripts{
736                 static_cast<evaluate::ConstantSubscript>(lenParams.size())}));
737   } else {
738     AddValue(values, componentSchema_, "lenvalue"s,
739         SomeExpr{evaluate::NullPointer{}});
740   }
741   // Shape information
742   int rank{evaluate::GetRank(shape)};
743   AddValue(values, componentSchema_, "rank"s, IntExpr<1>(rank));
744   if (rank > 0 && !IsAllocatable(symbol) && !IsPointer(symbol)) {
745     std::vector<evaluate::StructureConstructor> bounds;
746     evaluate::NamedEntity entity{symbol};
747     for (int j{0}; j < rank; ++j) {
748       bounds.emplace_back(GetValue(std::make_optional(evaluate::GetLowerBound(
749                                        foldingContext, entity, j)),
750           parameters));
751       bounds.emplace_back(GetValue(
752           evaluate::GetUpperBound(foldingContext, entity, j), parameters));
753     }
754     AddValue(values, componentSchema_, "bounds"s,
755         SaveDerivedPointerTarget(scope,
756             SaveObjectName(
757                 ".b."s + distinctName + "."s + symbol.name().ToString()),
758             std::move(bounds), evaluate::ConstantSubscripts{2, rank}));
759   } else {
760     AddValue(
761         values, componentSchema_, "bounds"s, SomeExpr{evaluate::NullPointer{}});
762   }
763   // Default component initialization
764   bool hasDataInit{false};
765   if (IsAllocatable(symbol)) {
766     AddValue(values, componentSchema_, "genre"s, GetEnumValue("allocatable"));
767   } else if (IsPointer(symbol)) {
768     AddValue(values, componentSchema_, "genre"s, GetEnumValue("pointer"));
769     hasDataInit = InitializeDataPointer(
770         values, symbol, object, scope, dtScope, distinctName);
771   } else if (IsAutomatic(symbol)) {
772     AddValue(values, componentSchema_, "genre"s, GetEnumValue("automatic"));
773   } else {
774     AddValue(values, componentSchema_, "genre"s, GetEnumValue("data"));
775     hasDataInit = object.init().has_value();
776     if (hasDataInit) {
777       AddValue(values, componentSchema_, "initialization"s,
778           SaveObjectInit(scope,
779               SaveObjectName(
780                   ".di."s + distinctName + "."s + symbol.name().ToString()),
781               object));
782     }
783   }
784   if (!hasDataInit) {
785     AddValue(values, componentSchema_, "initialization"s,
786         SomeExpr{evaluate::NullPointer{}});
787   }
788   return {DEREF(componentSchema_.AsDerived()), std::move(values)};
789 }
790 
791 evaluate::StructureConstructor RuntimeTableBuilder::DescribeComponent(
792     const Symbol &symbol, const ProcEntityDetails &proc, Scope &scope) {
793   evaluate::StructureConstructorValues values;
794   AddValue(values, procPtrSchema_, "name"s,
795       SaveNameAsPointerTarget(scope, symbol.name().ToString()));
796   AddValue(values, procPtrSchema_, "offset"s, IntExpr<8>(symbol.offset()));
797   if (auto init{proc.init()}; init && *init) {
798     AddValue(values, procPtrSchema_, "initialization"s,
799         SomeExpr{evaluate::ProcedureDesignator{**init}});
800   } else {
801     AddValue(values, procPtrSchema_, "initialization"s,
802         SomeExpr{evaluate::NullPointer{}});
803   }
804   return {DEREF(procPtrSchema_.AsDerived()), std::move(values)};
805 }
806 
807 // Create a static pointer object with the same initialization
808 // from whence the runtime can memcpy() the data pointer
809 // component initialization.
810 // Creates and interconnects the symbols, scopes, and types for
811 //   TYPE :: ptrDt
812 //     type, POINTER :: name
813 //   END TYPE
814 //   TYPE(ptrDt), TARGET, SAVE :: ptrInit = ptrDt(designator)
815 // and then initializes the original component by setting
816 //   initialization = ptrInit
817 // which takes the address of ptrInit because the type is C_PTR.
818 // This technique of wrapping the data pointer component into
819 // a derived type instance disables any reason for lowering to
820 // attempt to dereference the RHS of an initializer, thereby
821 // allowing the runtime to actually perform the initialization
822 // by means of a simple memcpy() of the wrapped descriptor in
823 // ptrInit to the data pointer component being initialized.
824 bool RuntimeTableBuilder::InitializeDataPointer(
825     evaluate::StructureConstructorValues &values, const Symbol &symbol,
826     const ObjectEntityDetails &object, Scope &scope, Scope &dtScope,
827     const std::string &distinctName) {
828   if (object.init().has_value()) {
829     SourceName ptrDtName{SaveObjectName(
830         ".dp."s + distinctName + "."s + symbol.name().ToString())};
831     Symbol &ptrDtSym{
832         *scope.try_emplace(ptrDtName, Attrs{}, UnknownDetails{}).first->second};
833     ptrDtSym.set(Symbol::Flag::CompilerCreated);
834     Scope &ptrDtScope{scope.MakeScope(Scope::Kind::DerivedType, &ptrDtSym)};
835     ignoreScopes_.insert(&ptrDtScope);
836     ObjectEntityDetails ptrDtObj;
837     ptrDtObj.set_type(DEREF(object.type()));
838     ptrDtObj.set_shape(object.shape());
839     Symbol &ptrDtComp{*ptrDtScope
840                            .try_emplace(symbol.name(), Attrs{Attr::POINTER},
841                                std::move(ptrDtObj))
842                            .first->second};
843     DerivedTypeDetails ptrDtDetails;
844     ptrDtDetails.add_component(ptrDtComp);
845     ptrDtSym.set_details(std::move(ptrDtDetails));
846     ptrDtSym.set_scope(&ptrDtScope);
847     DeclTypeSpec &ptrDtDeclType{
848         scope.MakeDerivedType(DeclTypeSpec::Category::TypeDerived,
849             DerivedTypeSpec{ptrDtName, ptrDtSym})};
850     DerivedTypeSpec &ptrDtDerived{DEREF(ptrDtDeclType.AsDerived())};
851     ptrDtDerived.set_scope(ptrDtScope);
852     ptrDtDerived.CookParameters(context_.foldingContext());
853     ptrDtDerived.Instantiate(scope);
854     ObjectEntityDetails ptrInitObj;
855     ptrInitObj.set_type(ptrDtDeclType);
856     evaluate::StructureConstructorValues ptrInitValues;
857     AddValue(
858         ptrInitValues, ptrDtDeclType, symbol.name().ToString(), *object.init());
859     ptrInitObj.set_init(evaluate::AsGenericExpr(
860         Structure(ptrDtDeclType, std::move(ptrInitValues))));
861     AddValue(values, componentSchema_, "initialization"s,
862         SaveObjectInit(scope,
863             SaveObjectName(
864                 ".di."s + distinctName + "."s + symbol.name().ToString()),
865             ptrInitObj));
866     return true;
867   } else {
868     return false;
869   }
870 }
871 
872 evaluate::StructureConstructor RuntimeTableBuilder::PackageIntValue(
873     const SomeExpr &genre, std::int64_t n) const {
874   evaluate::StructureConstructorValues xs;
875   AddValue(xs, valueSchema_, "genre"s, genre);
876   AddValue(xs, valueSchema_, "value"s, IntToExpr(n));
877   return Structure(valueSchema_, std::move(xs));
878 }
879 
880 SomeExpr RuntimeTableBuilder::PackageIntValueExpr(
881     const SomeExpr &genre, std::int64_t n) const {
882   return StructureExpr(PackageIntValue(genre, n));
883 }
884 
885 std::vector<const Symbol *> RuntimeTableBuilder::CollectBindings(
886     const Scope &dtScope) const {
887   std::vector<const Symbol *> result;
888   std::map<SourceName, const Symbol *> localBindings;
889   // Collect local bindings
890   for (auto pair : dtScope) {
891     const Symbol &symbol{*pair.second};
892     if (symbol.has<ProcBindingDetails>()) {
893       localBindings.emplace(symbol.name(), &symbol);
894     }
895   }
896   if (const Scope * parentScope{dtScope.GetDerivedTypeParent()}) {
897     result = CollectBindings(*parentScope);
898     // Apply overrides from the local bindings of the extended type
899     for (auto iter{result.begin()}; iter != result.end(); ++iter) {
900       const Symbol &symbol{**iter};
901       auto overridden{localBindings.find(symbol.name())};
902       if (overridden != localBindings.end()) {
903         *iter = overridden->second;
904         localBindings.erase(overridden);
905       }
906     }
907   }
908   // Add remaining (non-overriding) local bindings in name order to the result
909   for (auto pair : localBindings) {
910     result.push_back(pair.second);
911   }
912   return result;
913 }
914 
915 std::vector<evaluate::StructureConstructor>
916 RuntimeTableBuilder::DescribeBindings(const Scope &dtScope, Scope &scope) {
917   std::vector<evaluate::StructureConstructor> result;
918   for (const Symbol *symbol : CollectBindings(dtScope)) {
919     evaluate::StructureConstructorValues values;
920     AddValue(values, bindingSchema_, "proc"s,
921         SomeExpr{evaluate::ProcedureDesignator{
922             symbol->get<ProcBindingDetails>().symbol()}});
923     AddValue(values, bindingSchema_, "name"s,
924         SaveNameAsPointerTarget(scope, symbol->name().ToString()));
925     result.emplace_back(DEREF(bindingSchema_.AsDerived()), std::move(values));
926   }
927   return result;
928 }
929 
930 void RuntimeTableBuilder::DescribeGeneric(const GenericDetails &generic,
931     std::map<int, evaluate::StructureConstructor> &specials) {
932   std::visit(common::visitors{
933                  [&](const GenericKind::OtherKind &k) {
934                    if (k == GenericKind::OtherKind::Assignment) {
935                      for (auto ref : generic.specificProcs()) {
936                        DescribeSpecialProc(specials, *ref, true,
937                            false /*!final*/, std::nullopt);
938                      }
939                    }
940                  },
941                  [&](const GenericKind::DefinedIo &io) {
942                    switch (io) {
943                    case GenericKind::DefinedIo::ReadFormatted:
944                    case GenericKind::DefinedIo::ReadUnformatted:
945                    case GenericKind::DefinedIo::WriteFormatted:
946                    case GenericKind::DefinedIo::WriteUnformatted:
947                      for (auto ref : generic.specificProcs()) {
948                        DescribeSpecialProc(
949                            specials, *ref, false, false /*!final*/, io);
950                      }
951                      break;
952                    }
953                  },
954                  [](const auto &) {},
955              },
956       generic.kind().u);
957 }
958 
959 void RuntimeTableBuilder::DescribeSpecialProc(
960     std::map<int, evaluate::StructureConstructor> &specials,
961     const Symbol &specificOrBinding, bool isAssignment, bool isFinal,
962     std::optional<GenericKind::DefinedIo> io) {
963   const auto *binding{specificOrBinding.detailsIf<ProcBindingDetails>()};
964   const Symbol &specific{*(binding ? &binding->symbol() : &specificOrBinding)};
965   if (auto proc{evaluate::characteristics::Procedure::Characterize(
966           specific, context_.foldingContext())}) {
967     std::uint8_t isArgDescriptorSet{0};
968     int argThatMightBeDescriptor{0};
969     MaybeExpr which;
970     if (isAssignment) {
971       // Only type-bound asst's with the same type on both dummy arguments
972       // are germane to the runtime, which needs only these to implement
973       // component assignment as part of intrinsic assignment.
974       // Non-type-bound generic INTERFACEs and assignments from distinct
975       // types must not be used for component intrinsic assignment.
976       CHECK(proc->dummyArguments.size() == 2);
977       const auto t1{
978           DEREF(std::get_if<evaluate::characteristics::DummyDataObject>(
979                     &proc->dummyArguments[0].u))
980               .type.type()};
981       const auto t2{
982           DEREF(std::get_if<evaluate::characteristics::DummyDataObject>(
983                     &proc->dummyArguments[1].u))
984               .type.type()};
985       if (!binding || t1.category() != TypeCategory::Derived ||
986           t2.category() != TypeCategory::Derived ||
987           t1.IsUnlimitedPolymorphic() || t2.IsUnlimitedPolymorphic() ||
988           t1.GetDerivedTypeSpec() != t2.GetDerivedTypeSpec()) {
989         return;
990       }
991       which = proc->IsElemental() ? elementalAssignmentEnum_
992                                   : scalarAssignmentEnum_;
993       if (binding && binding->passName() &&
994           *binding->passName() == proc->dummyArguments[1].name) {
995         argThatMightBeDescriptor = 1;
996         isArgDescriptorSet |= 2;
997       } else {
998         argThatMightBeDescriptor = 2; // the non-passed-object argument
999         isArgDescriptorSet |= 1;
1000       }
1001     } else if (isFinal) {
1002       CHECK(binding == nullptr); // FINALs are not bindings
1003       CHECK(proc->dummyArguments.size() == 1);
1004       if (proc->IsElemental()) {
1005         which = elementalFinalEnum_;
1006       } else {
1007         const auto &typeAndShape{
1008             std::get<evaluate::characteristics::DummyDataObject>(
1009                 proc->dummyArguments.at(0).u)
1010                 .type};
1011         if (typeAndShape.attrs().test(
1012                 evaluate::characteristics::TypeAndShape::Attr::AssumedRank)) {
1013           which = assumedRankFinalEnum_;
1014           isArgDescriptorSet |= 1;
1015         } else {
1016           which = scalarFinalEnum_;
1017           if (int rank{evaluate::GetRank(typeAndShape.shape())}; rank > 0) {
1018             argThatMightBeDescriptor = 1;
1019             which = IntExpr<1>(ToInt64(which).value() + rank);
1020           }
1021         }
1022       }
1023     } else { // user defined derived type I/O
1024       CHECK(proc->dummyArguments.size() >= 4);
1025       if (binding) {
1026         isArgDescriptorSet |= 1;
1027       }
1028       switch (io.value()) {
1029       case GenericKind::DefinedIo::ReadFormatted:
1030         which = readFormattedEnum_;
1031         break;
1032       case GenericKind::DefinedIo::ReadUnformatted:
1033         which = readUnformattedEnum_;
1034         break;
1035       case GenericKind::DefinedIo::WriteFormatted:
1036         which = writeFormattedEnum_;
1037         break;
1038       case GenericKind::DefinedIo::WriteUnformatted:
1039         which = writeUnformattedEnum_;
1040         break;
1041       }
1042     }
1043     if (argThatMightBeDescriptor != 0 &&
1044         !proc->dummyArguments.at(argThatMightBeDescriptor - 1)
1045              .CanBePassedViaImplicitInterface()) {
1046       isArgDescriptorSet |= 1 << (argThatMightBeDescriptor - 1);
1047     }
1048     evaluate::StructureConstructorValues values;
1049     auto index{evaluate::ToInt64(which)};
1050     CHECK(index.has_value());
1051     AddValue(
1052         values, specialSchema_, "which"s, SomeExpr{std::move(which.value())});
1053     AddValue(values, specialSchema_, "isargdescriptorset"s,
1054         IntExpr<1>(isArgDescriptorSet));
1055     AddValue(values, specialSchema_, "proc"s,
1056         SomeExpr{evaluate::ProcedureDesignator{specific}});
1057     auto pair{specials.try_emplace(
1058         *index, DEREF(specialSchema_.AsDerived()), std::move(values))};
1059     CHECK(pair.second); // ensure not already present
1060   }
1061 }
1062 
1063 void RuntimeTableBuilder::IncorporateDefinedIoGenericInterfaces(
1064     std::map<int, evaluate::StructureConstructor> &specials, SourceName name,
1065     GenericKind::DefinedIo definedIo, const Scope *scope) {
1066   for (; !scope->IsGlobal(); scope = &scope->parent()) {
1067     if (auto asst{scope->find(name)}; asst != scope->end()) {
1068       const Symbol &generic{asst->second->GetUltimate()};
1069       const auto &genericDetails{generic.get<GenericDetails>()};
1070       CHECK(std::holds_alternative<GenericKind::DefinedIo>(
1071           genericDetails.kind().u));
1072       CHECK(std::get<GenericKind::DefinedIo>(genericDetails.kind().u) ==
1073           definedIo);
1074       for (auto ref : genericDetails.specificProcs()) {
1075         DescribeSpecialProc(specials, *ref, false, false, definedIo);
1076       }
1077     }
1078   }
1079 }
1080 
1081 RuntimeDerivedTypeTables BuildRuntimeDerivedTypeTables(
1082     SemanticsContext &context) {
1083   RuntimeDerivedTypeTables result;
1084   result.schemata = context.GetBuiltinModule("__fortran_type_info");
1085   if (result.schemata) {
1086     RuntimeTableBuilder builder{context, result};
1087     builder.DescribeTypes(context.globalScope(), false);
1088   }
1089   return result;
1090 }
1091 } // namespace Fortran::semantics
1092