1 //===-- lib/Semantics/check-io.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 "check-io.h"
10 #include "flang/Common/format.h"
11 #include "flang/Parser/tools.h"
12 #include "flang/Semantics/expression.h"
13 #include "flang/Semantics/tools.h"
14 #include <unordered_map>
15 
16 namespace Fortran::semantics {
17 
18 // TODO: C1234, C1235 -- defined I/O constraints
19 
20 class FormatErrorReporter {
21 public:
22   FormatErrorReporter(SemanticsContext &context,
23       const parser::CharBlock &formatCharBlock, int errorAllowance = 3)
24       : context_{context}, formatCharBlock_{formatCharBlock},
25         errorAllowance_{errorAllowance} {}
26 
27   bool Say(const common::FormatMessage &);
28 
29 private:
30   SemanticsContext &context_;
31   const parser::CharBlock &formatCharBlock_;
32   int errorAllowance_; // initialized to maximum number of errors to report
33 };
34 
35 bool FormatErrorReporter::Say(const common::FormatMessage &msg) {
36   if (!msg.isError && !context_.warnOnNonstandardUsage()) {
37     return false;
38   }
39   parser::MessageFormattedText text{
40       parser::MessageFixedText(msg.text, strlen(msg.text), msg.isError),
41       msg.arg};
42   if (formatCharBlock_.size()) {
43     // The input format is a folded expression.  Error markers span the full
44     // original unfolded expression in formatCharBlock_.
45     context_.Say(formatCharBlock_, text);
46   } else {
47     // The input format is a source expression.  Error markers have an offset
48     // and length relative to the beginning of formatCharBlock_.
49     parser::CharBlock messageCharBlock{
50         parser::CharBlock(formatCharBlock_.begin() + msg.offset, msg.length)};
51     context_.Say(messageCharBlock, text);
52   }
53   return msg.isError && --errorAllowance_ <= 0;
54 }
55 
56 void IoChecker::Enter(
57     const parser::Statement<common::Indirection<parser::FormatStmt>> &stmt) {
58   if (!stmt.label) {
59     context_.Say("Format statement must be labeled"_err_en_US); // C1301
60   }
61   const char *formatStart{static_cast<const char *>(
62       std::memchr(stmt.source.begin(), '(', stmt.source.size()))};
63   parser::CharBlock reporterCharBlock{formatStart, static_cast<std::size_t>(0)};
64   FormatErrorReporter reporter{context_, reporterCharBlock};
65   auto reporterWrapper{[&](const auto &msg) { return reporter.Say(msg); }};
66   switch (context_.GetDefaultKind(TypeCategory::Character)) {
67   case 1: {
68     common::FormatValidator<char> validator{formatStart,
69         stmt.source.size() - (formatStart - stmt.source.begin()),
70         reporterWrapper};
71     validator.Check();
72     break;
73   }
74   case 2: { // TODO: Get this to work.
75     common::FormatValidator<char16_t> validator{
76         /*???*/ nullptr, /*???*/ 0, reporterWrapper};
77     validator.Check();
78     break;
79   }
80   case 4: { // TODO: Get this to work.
81     common::FormatValidator<char32_t> validator{
82         /*???*/ nullptr, /*???*/ 0, reporterWrapper};
83     validator.Check();
84     break;
85   }
86   default:
87     CRASH_NO_CASE;
88   }
89 }
90 
91 void IoChecker::Enter(const parser::ConnectSpec &spec) {
92   // ConnectSpec context FileNameExpr
93   if (std::get_if<parser::FileNameExpr>(&spec.u)) {
94     SetSpecifier(IoSpecKind::File);
95   }
96 }
97 
98 void IoChecker::Enter(const parser::ConnectSpec::CharExpr &spec) {
99   IoSpecKind specKind{};
100   using ParseKind = parser::ConnectSpec::CharExpr::Kind;
101   switch (std::get<ParseKind>(spec.t)) {
102   case ParseKind::Access:
103     specKind = IoSpecKind::Access;
104     break;
105   case ParseKind::Action:
106     specKind = IoSpecKind::Action;
107     break;
108   case ParseKind::Asynchronous:
109     specKind = IoSpecKind::Asynchronous;
110     break;
111   case ParseKind::Blank:
112     specKind = IoSpecKind::Blank;
113     break;
114   case ParseKind::Decimal:
115     specKind = IoSpecKind::Decimal;
116     break;
117   case ParseKind::Delim:
118     specKind = IoSpecKind::Delim;
119     break;
120   case ParseKind::Encoding:
121     specKind = IoSpecKind::Encoding;
122     break;
123   case ParseKind::Form:
124     specKind = IoSpecKind::Form;
125     break;
126   case ParseKind::Pad:
127     specKind = IoSpecKind::Pad;
128     break;
129   case ParseKind::Position:
130     specKind = IoSpecKind::Position;
131     break;
132   case ParseKind::Round:
133     specKind = IoSpecKind::Round;
134     break;
135   case ParseKind::Sign:
136     specKind = IoSpecKind::Sign;
137     break;
138   case ParseKind::Carriagecontrol:
139     specKind = IoSpecKind::Carriagecontrol;
140     break;
141   case ParseKind::Convert:
142     specKind = IoSpecKind::Convert;
143     break;
144   case ParseKind::Dispose:
145     specKind = IoSpecKind::Dispose;
146     break;
147   }
148   SetSpecifier(specKind);
149   if (const std::optional<std::string> charConst{GetConstExpr<std::string>(
150           std::get<parser::ScalarDefaultCharExpr>(spec.t))}) {
151     std::string s{parser::ToUpperCaseLetters(*charConst)};
152     if (specKind == IoSpecKind::Access) {
153       flags_.set(Flag::KnownAccess);
154       flags_.set(Flag::AccessDirect, s == "DIRECT");
155       flags_.set(Flag::AccessStream, s == "STREAM");
156     }
157     CheckStringValue(specKind, *charConst, parser::FindSourceLocation(spec));
158     if (specKind == IoSpecKind::Carriagecontrol &&
159         (s == "FORTRAN" || s == "NONE")) {
160       context_.Say(parser::FindSourceLocation(spec),
161           "Unimplemented %s value '%s'"_err_en_US,
162           parser::ToUpperCaseLetters(common::EnumToString(specKind)),
163           *charConst);
164     }
165   }
166 }
167 
168 void IoChecker::Enter(const parser::ConnectSpec::Newunit &var) {
169   CheckForDefinableVariable(var, "NEWUNIT");
170   SetSpecifier(IoSpecKind::Newunit);
171 }
172 
173 void IoChecker::Enter(const parser::ConnectSpec::Recl &spec) {
174   SetSpecifier(IoSpecKind::Recl);
175   if (const std::optional<std::int64_t> recl{
176           GetConstExpr<std::int64_t>(spec)}) {
177     if (*recl <= 0) {
178       context_.Say(parser::FindSourceLocation(spec),
179           "RECL value (%jd) must be positive"_err_en_US,
180           *recl); // 12.5.6.15
181     }
182   }
183 }
184 
185 void IoChecker::Enter(const parser::EndLabel &) {
186   SetSpecifier(IoSpecKind::End);
187 }
188 
189 void IoChecker::Enter(const parser::EorLabel &) {
190   SetSpecifier(IoSpecKind::Eor);
191 }
192 
193 void IoChecker::Enter(const parser::ErrLabel &) {
194   SetSpecifier(IoSpecKind::Err);
195 }
196 
197 void IoChecker::Enter(const parser::FileUnitNumber &) {
198   SetSpecifier(IoSpecKind::Unit);
199   flags_.set(Flag::NumberUnit);
200 }
201 
202 void IoChecker::Enter(const parser::Format &spec) {
203   SetSpecifier(IoSpecKind::Fmt);
204   flags_.set(Flag::FmtOrNml);
205   std::visit(
206       common::visitors{
207           [&](const parser::Label &) { flags_.set(Flag::LabelFmt); },
208           [&](const parser::Star &) { flags_.set(Flag::StarFmt); },
209           [&](const parser::Expr &format) {
210             const SomeExpr *expr{GetExpr(format)};
211             if (!expr) {
212               return;
213             }
214             auto type{expr->GetType()};
215             if (!type ||
216                 (type->category() != TypeCategory::Integer &&
217                     type->category() != TypeCategory::Character) ||
218                 type->kind() !=
219                     context_.defaultKinds().GetDefaultKind(type->category())) {
220               context_.Say(format.source,
221                   "Format expression must be default character or integer"_err_en_US);
222               return;
223             }
224             if (type->category() == TypeCategory::Integer) {
225               flags_.set(Flag::AssignFmt);
226               if (expr->Rank() != 0 || !IsVariable(*expr)) {
227                 context_.Say(format.source,
228                     "Assigned format label must be a scalar variable"_err_en_US);
229               }
230               return;
231             }
232             flags_.set(Flag::CharFmt);
233             const std::optional<std::string> constantFormat{
234                 GetConstExpr<std::string>(format)};
235             if (!constantFormat) {
236               return;
237             }
238             // validate constant format -- 12.6.2.2
239             bool isFolded{constantFormat->size() != format.source.size() - 2};
240             parser::CharBlock reporterCharBlock{isFolded
241                     ? parser::CharBlock{format.source}
242                     : parser::CharBlock{format.source.begin() + 1,
243                           static_cast<std::size_t>(0)}};
244             FormatErrorReporter reporter{context_, reporterCharBlock};
245             auto reporterWrapper{
246                 [&](const auto &msg) { return reporter.Say(msg); }};
247             switch (context_.GetDefaultKind(TypeCategory::Character)) {
248             case 1: {
249               common::FormatValidator<char> validator{constantFormat->c_str(),
250                   constantFormat->length(), reporterWrapper, stmt_};
251               validator.Check();
252               break;
253             }
254             case 2: {
255               // TODO: Get this to work.  (Maybe combine with earlier instance?)
256               common::FormatValidator<char16_t> validator{
257                   /*???*/ nullptr, /*???*/ 0, reporterWrapper, stmt_};
258               validator.Check();
259               break;
260             }
261             case 4: {
262               // TODO: Get this to work.  (Maybe combine with earlier instance?)
263               common::FormatValidator<char32_t> validator{
264                   /*???*/ nullptr, /*???*/ 0, reporterWrapper, stmt_};
265               validator.Check();
266               break;
267             }
268             default:
269               CRASH_NO_CASE;
270             }
271           },
272       },
273       spec.u);
274 }
275 
276 void IoChecker::Enter(const parser::IdExpr &) { SetSpecifier(IoSpecKind::Id); }
277 
278 void IoChecker::Enter(const parser::IdVariable &spec) {
279   SetSpecifier(IoSpecKind::Id);
280   const auto *expr{GetExpr(spec)};
281   if (!expr || !expr->GetType()) {
282     return;
283   }
284   CheckForDefinableVariable(spec, "ID");
285   int kind{expr->GetType()->kind()};
286   int defaultKind{context_.GetDefaultKind(TypeCategory::Integer)};
287   if (kind < defaultKind) {
288     context_.Say(
289         "ID kind (%d) is smaller than default INTEGER kind (%d)"_err_en_US,
290         std::move(kind), std::move(defaultKind)); // C1229
291   }
292 }
293 
294 void IoChecker::Enter(const parser::InputItem &spec) {
295   flags_.set(Flag::DataList);
296   const parser::Variable *var{std::get_if<parser::Variable>(&spec.u)};
297   if (!var) {
298     return;
299   }
300   CheckForDefinableVariable(*var, "Input");
301   const auto &name{GetLastName(*var)};
302   const auto *expr{GetExpr(*var)};
303   if (name.symbol && IsAssumedSizeArray(*name.symbol) && expr &&
304       !evaluate::IsArrayElement(*GetExpr(*var))) {
305     context_.Say(name.source,
306         "Whole assumed size array '%s' may not be an input item"_err_en_US,
307         name.source); // C1231
308   }
309 }
310 
311 void IoChecker::Enter(const parser::InquireSpec &spec) {
312   // InquireSpec context FileNameExpr
313   if (std::get_if<parser::FileNameExpr>(&spec.u)) {
314     SetSpecifier(IoSpecKind::File);
315   }
316 }
317 
318 void IoChecker::Enter(const parser::InquireSpec::CharVar &spec) {
319   IoSpecKind specKind{};
320   using ParseKind = parser::InquireSpec::CharVar::Kind;
321   switch (std::get<ParseKind>(spec.t)) {
322   case ParseKind::Access:
323     specKind = IoSpecKind::Access;
324     break;
325   case ParseKind::Action:
326     specKind = IoSpecKind::Action;
327     break;
328   case ParseKind::Asynchronous:
329     specKind = IoSpecKind::Asynchronous;
330     break;
331   case ParseKind::Blank:
332     specKind = IoSpecKind::Blank;
333     break;
334   case ParseKind::Decimal:
335     specKind = IoSpecKind::Decimal;
336     break;
337   case ParseKind::Delim:
338     specKind = IoSpecKind::Delim;
339     break;
340   case ParseKind::Direct:
341     specKind = IoSpecKind::Direct;
342     break;
343   case ParseKind::Encoding:
344     specKind = IoSpecKind::Encoding;
345     break;
346   case ParseKind::Form:
347     specKind = IoSpecKind::Form;
348     break;
349   case ParseKind::Formatted:
350     specKind = IoSpecKind::Formatted;
351     break;
352   case ParseKind::Iomsg:
353     specKind = IoSpecKind::Iomsg;
354     break;
355   case ParseKind::Name:
356     specKind = IoSpecKind::Name;
357     break;
358   case ParseKind::Pad:
359     specKind = IoSpecKind::Pad;
360     break;
361   case ParseKind::Position:
362     specKind = IoSpecKind::Position;
363     break;
364   case ParseKind::Read:
365     specKind = IoSpecKind::Read;
366     break;
367   case ParseKind::Readwrite:
368     specKind = IoSpecKind::Readwrite;
369     break;
370   case ParseKind::Round:
371     specKind = IoSpecKind::Round;
372     break;
373   case ParseKind::Sequential:
374     specKind = IoSpecKind::Sequential;
375     break;
376   case ParseKind::Sign:
377     specKind = IoSpecKind::Sign;
378     break;
379   case ParseKind::Status:
380     specKind = IoSpecKind::Status;
381     break;
382   case ParseKind::Stream:
383     specKind = IoSpecKind::Stream;
384     break;
385   case ParseKind::Unformatted:
386     specKind = IoSpecKind::Unformatted;
387     break;
388   case ParseKind::Write:
389     specKind = IoSpecKind::Write;
390     break;
391   case ParseKind::Carriagecontrol:
392     specKind = IoSpecKind::Carriagecontrol;
393     break;
394   case ParseKind::Convert:
395     specKind = IoSpecKind::Convert;
396     break;
397   case ParseKind::Dispose:
398     specKind = IoSpecKind::Dispose;
399     break;
400   }
401   CheckForDefinableVariable(std::get<parser::ScalarDefaultCharVariable>(spec.t),
402       parser::ToUpperCaseLetters(common::EnumToString(specKind)));
403   SetSpecifier(specKind);
404 }
405 
406 void IoChecker::Enter(const parser::InquireSpec::IntVar &spec) {
407   IoSpecKind specKind{};
408   using ParseKind = parser::InquireSpec::IntVar::Kind;
409   switch (std::get<parser::InquireSpec::IntVar::Kind>(spec.t)) {
410   case ParseKind::Iostat:
411     specKind = IoSpecKind::Iostat;
412     break;
413   case ParseKind::Nextrec:
414     specKind = IoSpecKind::Nextrec;
415     break;
416   case ParseKind::Number:
417     specKind = IoSpecKind::Number;
418     break;
419   case ParseKind::Pos:
420     specKind = IoSpecKind::Pos;
421     break;
422   case ParseKind::Recl:
423     specKind = IoSpecKind::Recl;
424     break;
425   case ParseKind::Size:
426     specKind = IoSpecKind::Size;
427     break;
428   }
429   CheckForDefinableVariable(std::get<parser::ScalarIntVariable>(spec.t),
430       parser::ToUpperCaseLetters(common::EnumToString(specKind)));
431   SetSpecifier(specKind);
432 }
433 
434 void IoChecker::Enter(const parser::InquireSpec::LogVar &spec) {
435   IoSpecKind specKind{};
436   using ParseKind = parser::InquireSpec::LogVar::Kind;
437   switch (std::get<parser::InquireSpec::LogVar::Kind>(spec.t)) {
438   case ParseKind::Exist:
439     specKind = IoSpecKind::Exist;
440     break;
441   case ParseKind::Named:
442     specKind = IoSpecKind::Named;
443     break;
444   case ParseKind::Opened:
445     specKind = IoSpecKind::Opened;
446     break;
447   case ParseKind::Pending:
448     specKind = IoSpecKind::Pending;
449     break;
450   }
451   SetSpecifier(specKind);
452 }
453 
454 void IoChecker::Enter(const parser::IoControlSpec &spec) {
455   // IoControlSpec context Name
456   flags_.set(Flag::IoControlList);
457   if (std::holds_alternative<parser::Name>(spec.u)) {
458     SetSpecifier(IoSpecKind::Nml);
459     flags_.set(Flag::FmtOrNml);
460   }
461 }
462 
463 void IoChecker::Enter(const parser::IoControlSpec::Asynchronous &spec) {
464   SetSpecifier(IoSpecKind::Asynchronous);
465   if (const std::optional<std::string> charConst{
466           GetConstExpr<std::string>(spec)}) {
467     flags_.set(
468         Flag::AsynchronousYes, parser::ToUpperCaseLetters(*charConst) == "YES");
469     CheckStringValue(IoSpecKind::Asynchronous, *charConst,
470         parser::FindSourceLocation(spec)); // C1223
471   }
472 }
473 
474 void IoChecker::Enter(const parser::IoControlSpec::CharExpr &spec) {
475   IoSpecKind specKind{};
476   using ParseKind = parser::IoControlSpec::CharExpr::Kind;
477   switch (std::get<ParseKind>(spec.t)) {
478   case ParseKind::Advance:
479     specKind = IoSpecKind::Advance;
480     break;
481   case ParseKind::Blank:
482     specKind = IoSpecKind::Blank;
483     break;
484   case ParseKind::Decimal:
485     specKind = IoSpecKind::Decimal;
486     break;
487   case ParseKind::Delim:
488     specKind = IoSpecKind::Delim;
489     break;
490   case ParseKind::Pad:
491     specKind = IoSpecKind::Pad;
492     break;
493   case ParseKind::Round:
494     specKind = IoSpecKind::Round;
495     break;
496   case ParseKind::Sign:
497     specKind = IoSpecKind::Sign;
498     break;
499   }
500   SetSpecifier(specKind);
501   if (const std::optional<std::string> charConst{GetConstExpr<std::string>(
502           std::get<parser::ScalarDefaultCharExpr>(spec.t))}) {
503     if (specKind == IoSpecKind::Advance) {
504       flags_.set(
505           Flag::AdvanceYes, parser::ToUpperCaseLetters(*charConst) == "YES");
506     }
507     CheckStringValue(specKind, *charConst, parser::FindSourceLocation(spec));
508   }
509 }
510 
511 void IoChecker::Enter(const parser::IoControlSpec::Pos &) {
512   SetSpecifier(IoSpecKind::Pos);
513 }
514 
515 void IoChecker::Enter(const parser::IoControlSpec::Rec &) {
516   SetSpecifier(IoSpecKind::Rec);
517 }
518 
519 void IoChecker::Enter(const parser::IoControlSpec::Size &var) {
520   CheckForDefinableVariable(var, "SIZE");
521   SetSpecifier(IoSpecKind::Size);
522 }
523 
524 void IoChecker::Enter(const parser::IoUnit &spec) {
525   if (const parser::Variable * var{std::get_if<parser::Variable>(&spec.u)}) {
526     if (stmt_ == IoStmtKind::Write) {
527       CheckForDefinableVariable(*var, "Internal file");
528     }
529     if (const auto *expr{GetExpr(*var)}) {
530       if (HasVectorSubscript(*expr)) {
531         context_.Say(parser::FindSourceLocation(*var), // C1201
532             "Internal file must not have a vector subscript"_err_en_US);
533       } else if (!ExprTypeKindIsDefault(*expr, context_)) {
534         // This may be too restrictive; other kinds may be valid.
535         context_.Say(parser::FindSourceLocation(*var), // C1202
536             "Invalid character kind for an internal file variable"_err_en_US);
537       }
538     }
539     SetSpecifier(IoSpecKind::Unit);
540     flags_.set(Flag::InternalUnit);
541   } else if (std::get_if<parser::Star>(&spec.u)) {
542     SetSpecifier(IoSpecKind::Unit);
543     flags_.set(Flag::StarUnit);
544   }
545 }
546 
547 void IoChecker::Enter(const parser::MsgVariable &var) {
548   if (stmt_ == IoStmtKind::None) {
549     // allocate, deallocate, image control
550     CheckForDefinableVariable(var, "ERRMSG");
551     return;
552   }
553   CheckForDefinableVariable(var, "IOMSG");
554   SetSpecifier(IoSpecKind::Iomsg);
555 }
556 
557 void IoChecker::Enter(const parser::OutputItem &item) {
558   flags_.set(Flag::DataList);
559   if (const auto *x{std::get_if<parser::Expr>(&item.u)}) {
560     if (const auto *expr{GetExpr(*x)}) {
561       if (IsProcedurePointer(*expr)) {
562         context_.Say(parser::FindSourceLocation(*x),
563             "Output item must not be a procedure pointer"_err_en_US); // C1233
564       }
565     }
566   }
567 }
568 
569 void IoChecker::Enter(const parser::StatusExpr &spec) {
570   SetSpecifier(IoSpecKind::Status);
571   if (const std::optional<std::string> charConst{
572           GetConstExpr<std::string>(spec)}) {
573     // Status values for Open and Close are different.
574     std::string s{parser::ToUpperCaseLetters(*charConst)};
575     if (stmt_ == IoStmtKind::Open) {
576       flags_.set(Flag::KnownStatus);
577       flags_.set(Flag::StatusNew, s == "NEW");
578       flags_.set(Flag::StatusReplace, s == "REPLACE");
579       flags_.set(Flag::StatusScratch, s == "SCRATCH");
580       // CheckStringValue compares for OPEN Status string values.
581       CheckStringValue(
582           IoSpecKind::Status, *charConst, parser::FindSourceLocation(spec));
583       return;
584     }
585     CHECK(stmt_ == IoStmtKind::Close);
586     if (s != "DELETE" && s != "KEEP") {
587       context_.Say(parser::FindSourceLocation(spec),
588           "Invalid STATUS value '%s'"_err_en_US, *charConst);
589     }
590   }
591 }
592 
593 void IoChecker::Enter(const parser::StatVariable &var) {
594   if (stmt_ == IoStmtKind::None) {
595     // allocate, deallocate, image control
596     CheckForDefinableVariable(var, "STAT");
597     return;
598   }
599   CheckForDefinableVariable(var, "IOSTAT");
600   SetSpecifier(IoSpecKind::Iostat);
601 }
602 
603 void IoChecker::Leave(const parser::BackspaceStmt &) {
604   CheckForPureSubprogram();
605   CheckForRequiredSpecifier(
606       flags_.test(Flag::NumberUnit), "UNIT number"); // C1240
607   Done();
608 }
609 
610 void IoChecker::Leave(const parser::CloseStmt &) {
611   CheckForPureSubprogram();
612   CheckForRequiredSpecifier(
613       flags_.test(Flag::NumberUnit), "UNIT number"); // C1208
614   Done();
615 }
616 
617 void IoChecker::Leave(const parser::EndfileStmt &) {
618   CheckForPureSubprogram();
619   CheckForRequiredSpecifier(
620       flags_.test(Flag::NumberUnit), "UNIT number"); // C1240
621   Done();
622 }
623 
624 void IoChecker::Leave(const parser::FlushStmt &) {
625   CheckForPureSubprogram();
626   CheckForRequiredSpecifier(
627       flags_.test(Flag::NumberUnit), "UNIT number"); // C1243
628   Done();
629 }
630 
631 void IoChecker::Leave(const parser::InquireStmt &stmt) {
632   if (std::get_if<std::list<parser::InquireSpec>>(&stmt.u)) {
633     CheckForPureSubprogram();
634     // Inquire by unit or by file (vs. by output list).
635     CheckForRequiredSpecifier(
636         flags_.test(Flag::NumberUnit) || specifierSet_.test(IoSpecKind::File),
637         "UNIT number or FILE"); // C1246
638     CheckForProhibitedSpecifier(IoSpecKind::File, IoSpecKind::Unit); // C1246
639     CheckForRequiredSpecifier(IoSpecKind::Id, IoSpecKind::Pending); // C1248
640   }
641   Done();
642 }
643 
644 void IoChecker::Leave(const parser::OpenStmt &) {
645   CheckForPureSubprogram();
646   CheckForRequiredSpecifier(specifierSet_.test(IoSpecKind::Unit) ||
647           specifierSet_.test(IoSpecKind::Newunit),
648       "UNIT or NEWUNIT"); // C1204, C1205
649   CheckForProhibitedSpecifier(
650       IoSpecKind::Newunit, IoSpecKind::Unit); // C1204, C1205
651   CheckForRequiredSpecifier(flags_.test(Flag::StatusNew), "STATUS='NEW'",
652       IoSpecKind::File); // 12.5.6.10
653   CheckForRequiredSpecifier(flags_.test(Flag::StatusReplace),
654       "STATUS='REPLACE'", IoSpecKind::File); // 12.5.6.10
655   CheckForProhibitedSpecifier(flags_.test(Flag::StatusScratch),
656       "STATUS='SCRATCH'", IoSpecKind::File); // 12.5.6.10
657   if (flags_.test(Flag::KnownStatus)) {
658     CheckForRequiredSpecifier(IoSpecKind::Newunit,
659         specifierSet_.test(IoSpecKind::File) ||
660             flags_.test(Flag::StatusScratch),
661         "FILE or STATUS='SCRATCH'"); // 12.5.6.12
662   } else {
663     CheckForRequiredSpecifier(IoSpecKind::Newunit,
664         specifierSet_.test(IoSpecKind::File) ||
665             specifierSet_.test(IoSpecKind::Status),
666         "FILE or STATUS"); // 12.5.6.12
667   }
668   if (flags_.test(Flag::KnownAccess)) {
669     CheckForRequiredSpecifier(flags_.test(Flag::AccessDirect),
670         "ACCESS='DIRECT'", IoSpecKind::Recl); // 12.5.6.15
671     CheckForProhibitedSpecifier(flags_.test(Flag::AccessStream),
672         "STATUS='STREAM'", IoSpecKind::Recl); // 12.5.6.15
673   }
674   Done();
675 }
676 
677 void IoChecker::Leave(const parser::PrintStmt &) {
678   CheckForPureSubprogram();
679   Done();
680 }
681 
682 static void CheckForDoVariableInNamelist(const Symbol &namelist,
683     SemanticsContext &context, parser::CharBlock namelistLocation) {
684   const auto &details{namelist.GetUltimate().get<NamelistDetails>()};
685   for (const Symbol &object : details.objects()) {
686     context.CheckIndexVarRedefine(namelistLocation, object);
687   }
688 }
689 
690 static void CheckForDoVariableInNamelistSpec(
691     const parser::ReadStmt &readStmt, SemanticsContext &context) {
692   const std::list<parser::IoControlSpec> &controls{readStmt.controls};
693   for (const auto &control : controls) {
694     if (const auto *namelist{std::get_if<parser::Name>(&control.u)}) {
695       if (const Symbol * symbol{namelist->symbol}) {
696         CheckForDoVariableInNamelist(*symbol, context, namelist->source);
697       }
698     }
699   }
700 }
701 
702 static void CheckForDoVariable(
703     const parser::ReadStmt &readStmt, SemanticsContext &context) {
704   CheckForDoVariableInNamelistSpec(readStmt, context);
705   const std::list<parser::InputItem> &items{readStmt.items};
706   for (const auto &item : items) {
707     if (const parser::Variable *
708         variable{std::get_if<parser::Variable>(&item.u)}) {
709       context.CheckIndexVarRedefine(*variable);
710     }
711   }
712 }
713 
714 void IoChecker::Leave(const parser::ReadStmt &readStmt) {
715   if (!flags_.test(Flag::InternalUnit)) {
716     CheckForPureSubprogram();
717   }
718   CheckForDoVariable(readStmt, context_);
719   if (!flags_.test(Flag::IoControlList)) {
720     Done();
721     return;
722   }
723   LeaveReadWrite();
724   CheckForProhibitedSpecifier(IoSpecKind::Delim); // C1212
725   CheckForProhibitedSpecifier(IoSpecKind::Sign); // C1212
726   CheckForProhibitedSpecifier(IoSpecKind::Rec, IoSpecKind::End); // C1220
727   CheckForRequiredSpecifier(IoSpecKind::Eor,
728       specifierSet_.test(IoSpecKind::Advance) && !flags_.test(Flag::AdvanceYes),
729       "ADVANCE with value 'NO'"); // C1222 + 12.6.2.1p2
730   CheckForRequiredSpecifier(IoSpecKind::Blank, flags_.test(Flag::FmtOrNml),
731       "FMT or NML"); // C1227
732   CheckForRequiredSpecifier(
733       IoSpecKind::Pad, flags_.test(Flag::FmtOrNml), "FMT or NML"); // C1227
734   Done();
735 }
736 
737 void IoChecker::Leave(const parser::RewindStmt &) {
738   CheckForRequiredSpecifier(
739       flags_.test(Flag::NumberUnit), "UNIT number"); // C1240
740   CheckForPureSubprogram();
741   Done();
742 }
743 
744 void IoChecker::Leave(const parser::WaitStmt &) {
745   CheckForRequiredSpecifier(
746       flags_.test(Flag::NumberUnit), "UNIT number"); // C1237
747   CheckForPureSubprogram();
748   Done();
749 }
750 
751 void IoChecker::Leave(const parser::WriteStmt &) {
752   if (!flags_.test(Flag::InternalUnit)) {
753     CheckForPureSubprogram();
754   }
755   LeaveReadWrite();
756   CheckForProhibitedSpecifier(IoSpecKind::Blank); // C1213
757   CheckForProhibitedSpecifier(IoSpecKind::End); // C1213
758   CheckForProhibitedSpecifier(IoSpecKind::Eor); // C1213
759   CheckForProhibitedSpecifier(IoSpecKind::Pad); // C1213
760   CheckForProhibitedSpecifier(IoSpecKind::Size); // C1213
761   CheckForRequiredSpecifier(
762       IoSpecKind::Sign, flags_.test(Flag::FmtOrNml), "FMT or NML"); // C1227
763   CheckForRequiredSpecifier(IoSpecKind::Delim,
764       flags_.test(Flag::StarFmt) || specifierSet_.test(IoSpecKind::Nml),
765       "FMT=* or NML"); // C1228
766   Done();
767 }
768 
769 void IoChecker::LeaveReadWrite() const {
770   CheckForRequiredSpecifier(IoSpecKind::Unit); // C1211
771   CheckForProhibitedSpecifier(IoSpecKind::Nml, IoSpecKind::Rec); // C1216
772   CheckForProhibitedSpecifier(IoSpecKind::Nml, IoSpecKind::Fmt); // C1216
773   CheckForProhibitedSpecifier(
774       IoSpecKind::Nml, flags_.test(Flag::DataList), "a data list"); // C1216
775   CheckForProhibitedSpecifier(flags_.test(Flag::InternalUnit),
776       "UNIT=internal-file", IoSpecKind::Pos); // C1219
777   CheckForProhibitedSpecifier(flags_.test(Flag::InternalUnit),
778       "UNIT=internal-file", IoSpecKind::Rec); // C1219
779   CheckForProhibitedSpecifier(
780       flags_.test(Flag::StarUnit), "UNIT=*", IoSpecKind::Pos); // C1219
781   CheckForProhibitedSpecifier(
782       flags_.test(Flag::StarUnit), "UNIT=*", IoSpecKind::Rec); // C1219
783   CheckForProhibitedSpecifier(
784       IoSpecKind::Rec, flags_.test(Flag::StarFmt), "FMT=*"); // C1220
785   CheckForRequiredSpecifier(IoSpecKind::Advance,
786       flags_.test(Flag::CharFmt) || flags_.test(Flag::LabelFmt) ||
787           flags_.test(Flag::AssignFmt),
788       "an explicit format"); // C1221
789   CheckForProhibitedSpecifier(IoSpecKind::Advance,
790       flags_.test(Flag::InternalUnit), "UNIT=internal-file"); // C1221
791   CheckForRequiredSpecifier(flags_.test(Flag::AsynchronousYes),
792       "ASYNCHRONOUS='YES'", flags_.test(Flag::NumberUnit),
793       "UNIT=number"); // C1224
794   CheckForRequiredSpecifier(IoSpecKind::Id, flags_.test(Flag::AsynchronousYes),
795       "ASYNCHRONOUS='YES'"); // C1225
796   CheckForProhibitedSpecifier(IoSpecKind::Pos, IoSpecKind::Rec); // C1226
797   CheckForRequiredSpecifier(IoSpecKind::Decimal, flags_.test(Flag::FmtOrNml),
798       "FMT or NML"); // C1227
799   CheckForRequiredSpecifier(IoSpecKind::Round, flags_.test(Flag::FmtOrNml),
800       "FMT or NML"); // C1227
801 }
802 
803 void IoChecker::SetSpecifier(IoSpecKind specKind) {
804   if (stmt_ == IoStmtKind::None) {
805     // FMT may appear on PRINT statements, which don't have any checks.
806     // [IO]MSG and [IO]STAT parse symbols are shared with non-I/O statements.
807     return;
808   }
809   // C1203, C1207, C1210, C1236, C1239, C1242, C1245
810   if (specifierSet_.test(specKind)) {
811     context_.Say("Duplicate %s specifier"_err_en_US,
812         parser::ToUpperCaseLetters(common::EnumToString(specKind)));
813   }
814   specifierSet_.set(specKind);
815 }
816 
817 void IoChecker::CheckStringValue(IoSpecKind specKind, const std::string &value,
818     const parser::CharBlock &source) const {
819   static std::unordered_map<IoSpecKind, const std::set<std::string>> specValues{
820       {IoSpecKind::Access, {"DIRECT", "SEQUENTIAL", "STREAM"}},
821       {IoSpecKind::Action, {"READ", "READWRITE", "WRITE"}},
822       {IoSpecKind::Advance, {"NO", "YES"}},
823       {IoSpecKind::Asynchronous, {"NO", "YES"}},
824       {IoSpecKind::Blank, {"NULL", "ZERO"}},
825       {IoSpecKind::Decimal, {"COMMA", "POINT"}},
826       {IoSpecKind::Delim, {"APOSTROPHE", "NONE", "QUOTE"}},
827       {IoSpecKind::Encoding, {"DEFAULT", "UTF-8"}},
828       {IoSpecKind::Form, {"FORMATTED", "UNFORMATTED"}},
829       {IoSpecKind::Pad, {"NO", "YES"}},
830       {IoSpecKind::Position, {"APPEND", "ASIS", "REWIND"}},
831       {IoSpecKind::Round,
832           {"COMPATIBLE", "DOWN", "NEAREST", "PROCESSOR_DEFINED", "UP", "ZERO"}},
833       {IoSpecKind::Sign, {"PLUS", "PROCESSOR_DEFINED", "SUPPRESS"}},
834       {IoSpecKind::Status,
835           // Open values; Close values are {"DELETE", "KEEP"}.
836           {"NEW", "OLD", "REPLACE", "SCRATCH", "UNKNOWN"}},
837       {IoSpecKind::Carriagecontrol, {"LIST", "FORTRAN", "NONE"}},
838       {IoSpecKind::Convert, {"BIG_ENDIAN", "LITTLE_ENDIAN", "NATIVE"}},
839       {IoSpecKind::Dispose, {"DELETE", "KEEP"}},
840   };
841   if (!specValues.at(specKind).count(parser::ToUpperCaseLetters(value))) {
842     context_.Say(source, "Invalid %s value '%s'"_err_en_US,
843         parser::ToUpperCaseLetters(common::EnumToString(specKind)), value);
844   }
845 }
846 
847 // CheckForRequiredSpecifier and CheckForProhibitedSpecifier functions
848 // need conditions to check, and string arguments to insert into a message.
849 // An IoSpecKind provides both an absence/presence condition and a string
850 // argument (its name).  A (condition, string) pair provides an arbitrary
851 // condition and an arbitrary string.
852 
853 void IoChecker::CheckForRequiredSpecifier(IoSpecKind specKind) const {
854   if (!specifierSet_.test(specKind)) {
855     context_.Say("%s statement must have a %s specifier"_err_en_US,
856         parser::ToUpperCaseLetters(common::EnumToString(stmt_)),
857         parser::ToUpperCaseLetters(common::EnumToString(specKind)));
858   }
859 }
860 
861 void IoChecker::CheckForRequiredSpecifier(
862     bool condition, const std::string &s) const {
863   if (!condition) {
864     context_.Say("%s statement must have a %s specifier"_err_en_US,
865         parser::ToUpperCaseLetters(common::EnumToString(stmt_)), s);
866   }
867 }
868 
869 void IoChecker::CheckForRequiredSpecifier(
870     IoSpecKind specKind1, IoSpecKind specKind2) const {
871   if (specifierSet_.test(specKind1) && !specifierSet_.test(specKind2)) {
872     context_.Say("If %s appears, %s must also appear"_err_en_US,
873         parser::ToUpperCaseLetters(common::EnumToString(specKind1)),
874         parser::ToUpperCaseLetters(common::EnumToString(specKind2)));
875   }
876 }
877 
878 void IoChecker::CheckForRequiredSpecifier(
879     IoSpecKind specKind, bool condition, const std::string &s) const {
880   if (specifierSet_.test(specKind) && !condition) {
881     context_.Say("If %s appears, %s must also appear"_err_en_US,
882         parser::ToUpperCaseLetters(common::EnumToString(specKind)), s);
883   }
884 }
885 
886 void IoChecker::CheckForRequiredSpecifier(
887     bool condition, const std::string &s, IoSpecKind specKind) const {
888   if (condition && !specifierSet_.test(specKind)) {
889     context_.Say("If %s appears, %s must also appear"_err_en_US, s,
890         parser::ToUpperCaseLetters(common::EnumToString(specKind)));
891   }
892 }
893 
894 void IoChecker::CheckForRequiredSpecifier(bool condition1,
895     const std::string &s1, bool condition2, const std::string &s2) const {
896   if (condition1 && !condition2) {
897     context_.Say("If %s appears, %s must also appear"_err_en_US, s1, s2);
898   }
899 }
900 
901 void IoChecker::CheckForProhibitedSpecifier(IoSpecKind specKind) const {
902   if (specifierSet_.test(specKind)) {
903     context_.Say("%s statement must not have a %s specifier"_err_en_US,
904         parser::ToUpperCaseLetters(common::EnumToString(stmt_)),
905         parser::ToUpperCaseLetters(common::EnumToString(specKind)));
906   }
907 }
908 
909 void IoChecker::CheckForProhibitedSpecifier(
910     IoSpecKind specKind1, IoSpecKind specKind2) const {
911   if (specifierSet_.test(specKind1) && specifierSet_.test(specKind2)) {
912     context_.Say("If %s appears, %s must not appear"_err_en_US,
913         parser::ToUpperCaseLetters(common::EnumToString(specKind1)),
914         parser::ToUpperCaseLetters(common::EnumToString(specKind2)));
915   }
916 }
917 
918 void IoChecker::CheckForProhibitedSpecifier(
919     IoSpecKind specKind, bool condition, const std::string &s) const {
920   if (specifierSet_.test(specKind) && condition) {
921     context_.Say("If %s appears, %s must not appear"_err_en_US,
922         parser::ToUpperCaseLetters(common::EnumToString(specKind)), s);
923   }
924 }
925 
926 void IoChecker::CheckForProhibitedSpecifier(
927     bool condition, const std::string &s, IoSpecKind specKind) const {
928   if (condition && specifierSet_.test(specKind)) {
929     context_.Say("If %s appears, %s must not appear"_err_en_US, s,
930         parser::ToUpperCaseLetters(common::EnumToString(specKind)));
931   }
932 }
933 
934 template <typename A>
935 void IoChecker::CheckForDefinableVariable(
936     const A &var, const std::string &s) const {
937   const Symbol *sym{
938       GetFirstName(*parser::Unwrap<parser::Variable>(var)).symbol};
939   if (WhyNotModifiable(*sym, context_.FindScope(*context_.location()))) {
940     context_.Say(parser::FindSourceLocation(var),
941         "%s variable '%s' must be definable"_err_en_US, s, sym->name());
942   }
943 }
944 
945 void IoChecker::CheckForPureSubprogram() const { // C1597
946   CHECK(context_.location());
947   if (FindPureProcedureContaining(context_.FindScope(*context_.location()))) {
948     context_.Say("External I/O is not allowed in a pure subprogram"_err_en_US);
949   }
950 }
951 
952 } // namespace Fortran::semantics
953