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/Evaluate/tools.h"
12 #include "flang/Parser/tools.h"
13 #include "flang/Semantics/expression.h"
14 #include "flang/Semantics/tools.h"
15 #include <unordered_map>
16 
17 namespace Fortran::semantics {
18 
19 // TODO: C1234, C1235 -- defined I/O constraints
20 
21 class FormatErrorReporter {
22 public:
23   FormatErrorReporter(SemanticsContext &context,
24       const parser::CharBlock &formatCharBlock, int errorAllowance = 3)
25       : context_{context}, formatCharBlock_{formatCharBlock},
26         errorAllowance_{errorAllowance} {}
27 
28   bool Say(const common::FormatMessage &);
29 
30 private:
31   SemanticsContext &context_;
32   const parser::CharBlock &formatCharBlock_;
33   int errorAllowance_; // initialized to maximum number of errors to report
34 };
35 
36 bool FormatErrorReporter::Say(const common::FormatMessage &msg) {
37   if (!msg.isError && !context_.warnOnNonstandardUsage()) {
38     return false;
39   }
40   parser::MessageFormattedText text{
41       parser::MessageFixedText(msg.text, strlen(msg.text), msg.isError),
42       msg.arg};
43   if (formatCharBlock_.size()) {
44     // The input format is a folded expression.  Error markers span the full
45     // original unfolded expression in formatCharBlock_.
46     context_.Say(formatCharBlock_, text);
47   } else {
48     // The input format is a source expression.  Error markers have an offset
49     // and length relative to the beginning of formatCharBlock_.
50     parser::CharBlock messageCharBlock{
51         parser::CharBlock(formatCharBlock_.begin() + msg.offset, msg.length)};
52     context_.Say(messageCharBlock, text);
53   }
54   return msg.isError && --errorAllowance_ <= 0;
55 }
56 
57 void IoChecker::Enter(
58     const parser::Statement<common::Indirection<parser::FormatStmt>> &stmt) {
59   if (!stmt.label) {
60     context_.Say("Format statement must be labeled"_err_en_US); // C1301
61   }
62   const char *formatStart{static_cast<const char *>(
63       std::memchr(stmt.source.begin(), '(', stmt.source.size()))};
64   parser::CharBlock reporterCharBlock{formatStart, static_cast<std::size_t>(0)};
65   FormatErrorReporter reporter{context_, reporterCharBlock};
66   auto reporterWrapper{[&](const auto &msg) { return reporter.Say(msg); }};
67   switch (context_.GetDefaultKind(TypeCategory::Character)) {
68   case 1: {
69     common::FormatValidator<char> validator{formatStart,
70         stmt.source.size() - (formatStart - stmt.source.begin()),
71         reporterWrapper};
72     validator.Check();
73     break;
74   }
75   case 2: { // TODO: Get this to work.
76     common::FormatValidator<char16_t> validator{
77         /*???*/ nullptr, /*???*/ 0, reporterWrapper};
78     validator.Check();
79     break;
80   }
81   case 4: { // TODO: Get this to work.
82     common::FormatValidator<char32_t> validator{
83         /*???*/ nullptr, /*???*/ 0, reporterWrapper};
84     validator.Check();
85     break;
86   }
87   default:
88     CRASH_NO_CASE;
89   }
90 }
91 
92 void IoChecker::Enter(const parser::ConnectSpec &spec) {
93   // ConnectSpec context FileNameExpr
94   if (std::get_if<parser::FileNameExpr>(&spec.u)) {
95     SetSpecifier(IoSpecKind::File);
96   }
97 }
98 
99 void IoChecker::Enter(const parser::ConnectSpec::CharExpr &spec) {
100   IoSpecKind specKind{};
101   using ParseKind = parser::ConnectSpec::CharExpr::Kind;
102   switch (std::get<ParseKind>(spec.t)) {
103   case ParseKind::Access:
104     specKind = IoSpecKind::Access;
105     break;
106   case ParseKind::Action:
107     specKind = IoSpecKind::Action;
108     break;
109   case ParseKind::Asynchronous:
110     specKind = IoSpecKind::Asynchronous;
111     break;
112   case ParseKind::Blank:
113     specKind = IoSpecKind::Blank;
114     break;
115   case ParseKind::Decimal:
116     specKind = IoSpecKind::Decimal;
117     break;
118   case ParseKind::Delim:
119     specKind = IoSpecKind::Delim;
120     break;
121   case ParseKind::Encoding:
122     specKind = IoSpecKind::Encoding;
123     break;
124   case ParseKind::Form:
125     specKind = IoSpecKind::Form;
126     break;
127   case ParseKind::Pad:
128     specKind = IoSpecKind::Pad;
129     break;
130   case ParseKind::Position:
131     specKind = IoSpecKind::Position;
132     break;
133   case ParseKind::Round:
134     specKind = IoSpecKind::Round;
135     break;
136   case ParseKind::Sign:
137     specKind = IoSpecKind::Sign;
138     break;
139   case ParseKind::Carriagecontrol:
140     specKind = IoSpecKind::Carriagecontrol;
141     break;
142   case ParseKind::Convert:
143     specKind = IoSpecKind::Convert;
144     break;
145   case ParseKind::Dispose:
146     specKind = IoSpecKind::Dispose;
147     break;
148   }
149   SetSpecifier(specKind);
150   if (const std::optional<std::string> charConst{GetConstExpr<std::string>(
151           std::get<parser::ScalarDefaultCharExpr>(spec.t))}) {
152     std::string s{parser::ToUpperCaseLetters(*charConst)};
153     if (specKind == IoSpecKind::Access) {
154       flags_.set(Flag::KnownAccess);
155       flags_.set(Flag::AccessDirect, s == "DIRECT");
156       flags_.set(Flag::AccessStream, s == "STREAM");
157     }
158     CheckStringValue(specKind, *charConst, parser::FindSourceLocation(spec));
159     if (specKind == IoSpecKind::Carriagecontrol &&
160         (s == "FORTRAN" || s == "NONE")) {
161       context_.Say(parser::FindSourceLocation(spec),
162           "Unimplemented %s value '%s'"_err_en_US,
163           parser::ToUpperCaseLetters(common::EnumToString(specKind)),
164           *charConst);
165     }
166   }
167 }
168 
169 void IoChecker::Enter(const parser::ConnectSpec::Newunit &var) {
170   CheckForDefinableVariable(var, "NEWUNIT");
171   SetSpecifier(IoSpecKind::Newunit);
172 }
173 
174 void IoChecker::Enter(const parser::ConnectSpec::Recl &spec) {
175   SetSpecifier(IoSpecKind::Recl);
176   if (const std::optional<std::int64_t> recl{
177           GetConstExpr<std::int64_t>(spec)}) {
178     if (*recl <= 0) {
179       context_.Say(parser::FindSourceLocation(spec),
180           "RECL value (%jd) must be positive"_err_en_US,
181           *recl); // 12.5.6.15
182     }
183   }
184 }
185 
186 void IoChecker::Enter(const parser::EndLabel &) {
187   SetSpecifier(IoSpecKind::End);
188 }
189 
190 void IoChecker::Enter(const parser::EorLabel &) {
191   SetSpecifier(IoSpecKind::Eor);
192 }
193 
194 void IoChecker::Enter(const parser::ErrLabel &) {
195   SetSpecifier(IoSpecKind::Err);
196 }
197 
198 void IoChecker::Enter(const parser::FileUnitNumber &) {
199   SetSpecifier(IoSpecKind::Unit);
200   flags_.set(Flag::NumberUnit);
201 }
202 
203 void IoChecker::Enter(const parser::Format &spec) {
204   SetSpecifier(IoSpecKind::Fmt);
205   flags_.set(Flag::FmtOrNml);
206   std::visit(
207       common::visitors{
208           [&](const parser::Label &) { flags_.set(Flag::LabelFmt); },
209           [&](const parser::Star &) { flags_.set(Flag::StarFmt); },
210           [&](const parser::Expr &format) {
211             const SomeExpr *expr{GetExpr(format)};
212             if (!expr) {
213               return;
214             }
215             auto type{expr->GetType()};
216             if (type && type->category() == TypeCategory::Integer &&
217                 type->kind() ==
218                     context_.defaultKinds().GetDefaultKind(type->category()) &&
219                 expr->Rank() == 0) {
220               flags_.set(Flag::AssignFmt);
221               if (!IsVariable(*expr)) {
222                 context_.Say(format.source,
223                     "Assigned format label must be a scalar variable"_err_en_US);
224               }
225               return;
226             }
227             if (type && type->category() != TypeCategory::Character &&
228                 (type->category() != TypeCategory::Integer ||
229                     expr->Rank() > 0) &&
230                 context_.IsEnabled(
231                     common::LanguageFeature::NonCharacterFormat)) {
232               // Legacy extension: using non-character variables, typically
233               // DATA-initialized with Hollerith, as format expressions.
234               if (context_.ShouldWarn(
235                       common::LanguageFeature::NonCharacterFormat)) {
236                 context_.Say(format.source,
237                     "Non-character format expression is not standard"_en_US);
238               }
239             } else if (!type ||
240                 type->kind() !=
241                     context_.defaultKinds().GetDefaultKind(type->category())) {
242               context_.Say(format.source,
243                   "Format expression must be default character or default scalar integer"_err_en_US);
244               return;
245             }
246             if (expr->Rank() > 0 &&
247                 !IsSimplyContiguous(*expr, context_.foldingContext())) {
248               // The runtime APIs don't allow arbitrary descriptors for formats.
249               context_.Say(format.source,
250                   "Format expression must be a simply contiguous array if not scalar"_err_en_US);
251               return;
252             }
253             flags_.set(Flag::CharFmt);
254             const std::optional<std::string> constantFormat{
255                 GetConstExpr<std::string>(format)};
256             if (!constantFormat) {
257               return;
258             }
259             // validate constant format -- 12.6.2.2
260             bool isFolded{constantFormat->size() != format.source.size() - 2};
261             parser::CharBlock reporterCharBlock{isFolded
262                     ? parser::CharBlock{format.source}
263                     : parser::CharBlock{format.source.begin() + 1,
264                           static_cast<std::size_t>(0)}};
265             FormatErrorReporter reporter{context_, reporterCharBlock};
266             auto reporterWrapper{
267                 [&](const auto &msg) { return reporter.Say(msg); }};
268             switch (context_.GetDefaultKind(TypeCategory::Character)) {
269             case 1: {
270               common::FormatValidator<char> validator{constantFormat->c_str(),
271                   constantFormat->length(), reporterWrapper, stmt_};
272               validator.Check();
273               break;
274             }
275             case 2: {
276               // TODO: Get this to work.  (Maybe combine with earlier instance?)
277               common::FormatValidator<char16_t> validator{
278                   /*???*/ nullptr, /*???*/ 0, reporterWrapper, stmt_};
279               validator.Check();
280               break;
281             }
282             case 4: {
283               // TODO: Get this to work.  (Maybe combine with earlier instance?)
284               common::FormatValidator<char32_t> validator{
285                   /*???*/ nullptr, /*???*/ 0, reporterWrapper, stmt_};
286               validator.Check();
287               break;
288             }
289             default:
290               CRASH_NO_CASE;
291             }
292           },
293       },
294       spec.u);
295 }
296 
297 void IoChecker::Enter(const parser::IdExpr &) { SetSpecifier(IoSpecKind::Id); }
298 
299 void IoChecker::Enter(const parser::IdVariable &spec) {
300   SetSpecifier(IoSpecKind::Id);
301   const auto *expr{GetExpr(spec)};
302   if (!expr || !expr->GetType()) {
303     return;
304   }
305   CheckForDefinableVariable(spec, "ID");
306   int kind{expr->GetType()->kind()};
307   int defaultKind{context_.GetDefaultKind(TypeCategory::Integer)};
308   if (kind < defaultKind) {
309     context_.Say(
310         "ID kind (%d) is smaller than default INTEGER kind (%d)"_err_en_US,
311         std::move(kind), std::move(defaultKind)); // C1229
312   }
313 }
314 
315 void IoChecker::Enter(const parser::InputItem &spec) {
316   flags_.set(Flag::DataList);
317   const parser::Variable *var{std::get_if<parser::Variable>(&spec.u)};
318   if (!var) {
319     return;
320   }
321   CheckForDefinableVariable(*var, "Input");
322 }
323 
324 void IoChecker::Enter(const parser::InquireSpec &spec) {
325   // InquireSpec context FileNameExpr
326   if (std::get_if<parser::FileNameExpr>(&spec.u)) {
327     SetSpecifier(IoSpecKind::File);
328   }
329 }
330 
331 void IoChecker::Enter(const parser::InquireSpec::CharVar &spec) {
332   IoSpecKind specKind{};
333   using ParseKind = parser::InquireSpec::CharVar::Kind;
334   switch (std::get<ParseKind>(spec.t)) {
335   case ParseKind::Access:
336     specKind = IoSpecKind::Access;
337     break;
338   case ParseKind::Action:
339     specKind = IoSpecKind::Action;
340     break;
341   case ParseKind::Asynchronous:
342     specKind = IoSpecKind::Asynchronous;
343     break;
344   case ParseKind::Blank:
345     specKind = IoSpecKind::Blank;
346     break;
347   case ParseKind::Decimal:
348     specKind = IoSpecKind::Decimal;
349     break;
350   case ParseKind::Delim:
351     specKind = IoSpecKind::Delim;
352     break;
353   case ParseKind::Direct:
354     specKind = IoSpecKind::Direct;
355     break;
356   case ParseKind::Encoding:
357     specKind = IoSpecKind::Encoding;
358     break;
359   case ParseKind::Form:
360     specKind = IoSpecKind::Form;
361     break;
362   case ParseKind::Formatted:
363     specKind = IoSpecKind::Formatted;
364     break;
365   case ParseKind::Iomsg:
366     specKind = IoSpecKind::Iomsg;
367     break;
368   case ParseKind::Name:
369     specKind = IoSpecKind::Name;
370     break;
371   case ParseKind::Pad:
372     specKind = IoSpecKind::Pad;
373     break;
374   case ParseKind::Position:
375     specKind = IoSpecKind::Position;
376     break;
377   case ParseKind::Read:
378     specKind = IoSpecKind::Read;
379     break;
380   case ParseKind::Readwrite:
381     specKind = IoSpecKind::Readwrite;
382     break;
383   case ParseKind::Round:
384     specKind = IoSpecKind::Round;
385     break;
386   case ParseKind::Sequential:
387     specKind = IoSpecKind::Sequential;
388     break;
389   case ParseKind::Sign:
390     specKind = IoSpecKind::Sign;
391     break;
392   case ParseKind::Status:
393     specKind = IoSpecKind::Status;
394     break;
395   case ParseKind::Stream:
396     specKind = IoSpecKind::Stream;
397     break;
398   case ParseKind::Unformatted:
399     specKind = IoSpecKind::Unformatted;
400     break;
401   case ParseKind::Write:
402     specKind = IoSpecKind::Write;
403     break;
404   case ParseKind::Carriagecontrol:
405     specKind = IoSpecKind::Carriagecontrol;
406     break;
407   case ParseKind::Convert:
408     specKind = IoSpecKind::Convert;
409     break;
410   case ParseKind::Dispose:
411     specKind = IoSpecKind::Dispose;
412     break;
413   }
414   CheckForDefinableVariable(std::get<parser::ScalarDefaultCharVariable>(spec.t),
415       parser::ToUpperCaseLetters(common::EnumToString(specKind)));
416   SetSpecifier(specKind);
417 }
418 
419 void IoChecker::Enter(const parser::InquireSpec::IntVar &spec) {
420   IoSpecKind specKind{};
421   using ParseKind = parser::InquireSpec::IntVar::Kind;
422   switch (std::get<parser::InquireSpec::IntVar::Kind>(spec.t)) {
423   case ParseKind::Iostat:
424     specKind = IoSpecKind::Iostat;
425     break;
426   case ParseKind::Nextrec:
427     specKind = IoSpecKind::Nextrec;
428     break;
429   case ParseKind::Number:
430     specKind = IoSpecKind::Number;
431     break;
432   case ParseKind::Pos:
433     specKind = IoSpecKind::Pos;
434     break;
435   case ParseKind::Recl:
436     specKind = IoSpecKind::Recl;
437     break;
438   case ParseKind::Size:
439     specKind = IoSpecKind::Size;
440     break;
441   }
442   CheckForDefinableVariable(std::get<parser::ScalarIntVariable>(spec.t),
443       parser::ToUpperCaseLetters(common::EnumToString(specKind)));
444   SetSpecifier(specKind);
445 }
446 
447 void IoChecker::Enter(const parser::InquireSpec::LogVar &spec) {
448   IoSpecKind specKind{};
449   using ParseKind = parser::InquireSpec::LogVar::Kind;
450   switch (std::get<parser::InquireSpec::LogVar::Kind>(spec.t)) {
451   case ParseKind::Exist:
452     specKind = IoSpecKind::Exist;
453     break;
454   case ParseKind::Named:
455     specKind = IoSpecKind::Named;
456     break;
457   case ParseKind::Opened:
458     specKind = IoSpecKind::Opened;
459     break;
460   case ParseKind::Pending:
461     specKind = IoSpecKind::Pending;
462     break;
463   }
464   SetSpecifier(specKind);
465 }
466 
467 void IoChecker::Enter(const parser::IoControlSpec &spec) {
468   // IoControlSpec context Name
469   flags_.set(Flag::IoControlList);
470   if (std::holds_alternative<parser::Name>(spec.u)) {
471     SetSpecifier(IoSpecKind::Nml);
472     flags_.set(Flag::FmtOrNml);
473   }
474 }
475 
476 void IoChecker::Enter(const parser::IoControlSpec::Asynchronous &spec) {
477   SetSpecifier(IoSpecKind::Asynchronous);
478   if (const std::optional<std::string> charConst{
479           GetConstExpr<std::string>(spec)}) {
480     flags_.set(
481         Flag::AsynchronousYes, parser::ToUpperCaseLetters(*charConst) == "YES");
482     CheckStringValue(IoSpecKind::Asynchronous, *charConst,
483         parser::FindSourceLocation(spec)); // C1223
484   }
485 }
486 
487 void IoChecker::Enter(const parser::IoControlSpec::CharExpr &spec) {
488   IoSpecKind specKind{};
489   using ParseKind = parser::IoControlSpec::CharExpr::Kind;
490   switch (std::get<ParseKind>(spec.t)) {
491   case ParseKind::Advance:
492     specKind = IoSpecKind::Advance;
493     break;
494   case ParseKind::Blank:
495     specKind = IoSpecKind::Blank;
496     break;
497   case ParseKind::Decimal:
498     specKind = IoSpecKind::Decimal;
499     break;
500   case ParseKind::Delim:
501     specKind = IoSpecKind::Delim;
502     break;
503   case ParseKind::Pad:
504     specKind = IoSpecKind::Pad;
505     break;
506   case ParseKind::Round:
507     specKind = IoSpecKind::Round;
508     break;
509   case ParseKind::Sign:
510     specKind = IoSpecKind::Sign;
511     break;
512   }
513   SetSpecifier(specKind);
514   if (const std::optional<std::string> charConst{GetConstExpr<std::string>(
515           std::get<parser::ScalarDefaultCharExpr>(spec.t))}) {
516     if (specKind == IoSpecKind::Advance) {
517       flags_.set(
518           Flag::AdvanceYes, parser::ToUpperCaseLetters(*charConst) == "YES");
519     }
520     CheckStringValue(specKind, *charConst, parser::FindSourceLocation(spec));
521   }
522 }
523 
524 void IoChecker::Enter(const parser::IoControlSpec::Pos &) {
525   SetSpecifier(IoSpecKind::Pos);
526 }
527 
528 void IoChecker::Enter(const parser::IoControlSpec::Rec &) {
529   SetSpecifier(IoSpecKind::Rec);
530 }
531 
532 void IoChecker::Enter(const parser::IoControlSpec::Size &var) {
533   CheckForDefinableVariable(var, "SIZE");
534   SetSpecifier(IoSpecKind::Size);
535 }
536 
537 void IoChecker::Enter(const parser::IoUnit &spec) {
538   if (const parser::Variable * var{std::get_if<parser::Variable>(&spec.u)}) {
539     if (stmt_ == IoStmtKind::Write) {
540       CheckForDefinableVariable(*var, "Internal file");
541     }
542     if (const auto *expr{GetExpr(*var)}) {
543       if (HasVectorSubscript(*expr)) {
544         context_.Say(parser::FindSourceLocation(*var), // C1201
545             "Internal file must not have a vector subscript"_err_en_US);
546       } else if (!ExprTypeKindIsDefault(*expr, context_)) {
547         // This may be too restrictive; other kinds may be valid.
548         context_.Say(parser::FindSourceLocation(*var), // C1202
549             "Invalid character kind for an internal file variable"_err_en_US);
550       }
551     }
552     SetSpecifier(IoSpecKind::Unit);
553     flags_.set(Flag::InternalUnit);
554   } else if (std::get_if<parser::Star>(&spec.u)) {
555     SetSpecifier(IoSpecKind::Unit);
556     flags_.set(Flag::StarUnit);
557   }
558 }
559 
560 void IoChecker::Enter(const parser::MsgVariable &var) {
561   if (stmt_ == IoStmtKind::None) {
562     // allocate, deallocate, image control
563     CheckForDefinableVariable(var, "ERRMSG");
564     return;
565   }
566   CheckForDefinableVariable(var, "IOMSG");
567   SetSpecifier(IoSpecKind::Iomsg);
568 }
569 
570 void IoChecker::Enter(const parser::OutputItem &item) {
571   flags_.set(Flag::DataList);
572   if (const auto *x{std::get_if<parser::Expr>(&item.u)}) {
573     if (const auto *expr{GetExpr(*x)}) {
574       if (evaluate::IsBOZLiteral(*expr)) {
575         context_.Say(parser::FindSourceLocation(*x), // C7109
576             "Output item must not be a BOZ literal constant"_err_en_US);
577       }
578       const Symbol *last{GetLastSymbol(*expr)};
579       if (last && IsProcedurePointer(*last)) {
580         context_.Say(parser::FindSourceLocation(*x),
581             "Output item must not be a procedure pointer"_err_en_US); // C1233
582       }
583     }
584   }
585 }
586 
587 void IoChecker::Enter(const parser::StatusExpr &spec) {
588   SetSpecifier(IoSpecKind::Status);
589   if (const std::optional<std::string> charConst{
590           GetConstExpr<std::string>(spec)}) {
591     // Status values for Open and Close are different.
592     std::string s{parser::ToUpperCaseLetters(*charConst)};
593     if (stmt_ == IoStmtKind::Open) {
594       flags_.set(Flag::KnownStatus);
595       flags_.set(Flag::StatusNew, s == "NEW");
596       flags_.set(Flag::StatusReplace, s == "REPLACE");
597       flags_.set(Flag::StatusScratch, s == "SCRATCH");
598       // CheckStringValue compares for OPEN Status string values.
599       CheckStringValue(
600           IoSpecKind::Status, *charConst, parser::FindSourceLocation(spec));
601       return;
602     }
603     CHECK(stmt_ == IoStmtKind::Close);
604     if (s != "DELETE" && s != "KEEP") {
605       context_.Say(parser::FindSourceLocation(spec),
606           "Invalid STATUS value '%s'"_err_en_US, *charConst);
607     }
608   }
609 }
610 
611 void IoChecker::Enter(const parser::StatVariable &var) {
612   if (stmt_ == IoStmtKind::None) {
613     // allocate, deallocate, image control
614     CheckForDefinableVariable(var, "STAT");
615     return;
616   }
617   CheckForDefinableVariable(var, "IOSTAT");
618   SetSpecifier(IoSpecKind::Iostat);
619 }
620 
621 void IoChecker::Leave(const parser::BackspaceStmt &) {
622   CheckForPureSubprogram();
623   CheckForRequiredSpecifier(
624       flags_.test(Flag::NumberUnit), "UNIT number"); // C1240
625   Done();
626 }
627 
628 void IoChecker::Leave(const parser::CloseStmt &) {
629   CheckForPureSubprogram();
630   CheckForRequiredSpecifier(
631       flags_.test(Flag::NumberUnit), "UNIT number"); // C1208
632   Done();
633 }
634 
635 void IoChecker::Leave(const parser::EndfileStmt &) {
636   CheckForPureSubprogram();
637   CheckForRequiredSpecifier(
638       flags_.test(Flag::NumberUnit), "UNIT number"); // C1240
639   Done();
640 }
641 
642 void IoChecker::Leave(const parser::FlushStmt &) {
643   CheckForPureSubprogram();
644   CheckForRequiredSpecifier(
645       flags_.test(Flag::NumberUnit), "UNIT number"); // C1243
646   Done();
647 }
648 
649 void IoChecker::Leave(const parser::InquireStmt &stmt) {
650   if (std::get_if<std::list<parser::InquireSpec>>(&stmt.u)) {
651     CheckForPureSubprogram();
652     // Inquire by unit or by file (vs. by output list).
653     CheckForRequiredSpecifier(
654         flags_.test(Flag::NumberUnit) || specifierSet_.test(IoSpecKind::File),
655         "UNIT number or FILE"); // C1246
656     CheckForProhibitedSpecifier(IoSpecKind::File, IoSpecKind::Unit); // C1246
657     CheckForRequiredSpecifier(IoSpecKind::Id, IoSpecKind::Pending); // C1248
658   }
659   Done();
660 }
661 
662 void IoChecker::Leave(const parser::OpenStmt &) {
663   CheckForPureSubprogram();
664   CheckForRequiredSpecifier(specifierSet_.test(IoSpecKind::Unit) ||
665           specifierSet_.test(IoSpecKind::Newunit),
666       "UNIT or NEWUNIT"); // C1204, C1205
667   CheckForProhibitedSpecifier(
668       IoSpecKind::Newunit, IoSpecKind::Unit); // C1204, C1205
669   CheckForRequiredSpecifier(flags_.test(Flag::StatusNew), "STATUS='NEW'",
670       IoSpecKind::File); // 12.5.6.10
671   CheckForRequiredSpecifier(flags_.test(Flag::StatusReplace),
672       "STATUS='REPLACE'", IoSpecKind::File); // 12.5.6.10
673   CheckForProhibitedSpecifier(flags_.test(Flag::StatusScratch),
674       "STATUS='SCRATCH'", IoSpecKind::File); // 12.5.6.10
675   if (flags_.test(Flag::KnownStatus)) {
676     CheckForRequiredSpecifier(IoSpecKind::Newunit,
677         specifierSet_.test(IoSpecKind::File) ||
678             flags_.test(Flag::StatusScratch),
679         "FILE or STATUS='SCRATCH'"); // 12.5.6.12
680   } else {
681     CheckForRequiredSpecifier(IoSpecKind::Newunit,
682         specifierSet_.test(IoSpecKind::File) ||
683             specifierSet_.test(IoSpecKind::Status),
684         "FILE or STATUS"); // 12.5.6.12
685   }
686   if (flags_.test(Flag::KnownAccess)) {
687     CheckForRequiredSpecifier(flags_.test(Flag::AccessDirect),
688         "ACCESS='DIRECT'", IoSpecKind::Recl); // 12.5.6.15
689     CheckForProhibitedSpecifier(flags_.test(Flag::AccessStream),
690         "STATUS='STREAM'", IoSpecKind::Recl); // 12.5.6.15
691   }
692   Done();
693 }
694 
695 void IoChecker::Leave(const parser::PrintStmt &) {
696   CheckForPureSubprogram();
697   Done();
698 }
699 
700 static void CheckForDoVariableInNamelist(const Symbol &namelist,
701     SemanticsContext &context, parser::CharBlock namelistLocation) {
702   const auto &details{namelist.GetUltimate().get<NamelistDetails>()};
703   for (const Symbol &object : details.objects()) {
704     context.CheckIndexVarRedefine(namelistLocation, object);
705   }
706 }
707 
708 static void CheckForDoVariableInNamelistSpec(
709     const parser::ReadStmt &readStmt, SemanticsContext &context) {
710   const std::list<parser::IoControlSpec> &controls{readStmt.controls};
711   for (const auto &control : controls) {
712     if (const auto *namelist{std::get_if<parser::Name>(&control.u)}) {
713       if (const Symbol * symbol{namelist->symbol}) {
714         CheckForDoVariableInNamelist(*symbol, context, namelist->source);
715       }
716     }
717   }
718 }
719 
720 static void CheckForDoVariable(
721     const parser::ReadStmt &readStmt, SemanticsContext &context) {
722   CheckForDoVariableInNamelistSpec(readStmt, context);
723   const std::list<parser::InputItem> &items{readStmt.items};
724   for (const auto &item : items) {
725     if (const parser::Variable *
726         variable{std::get_if<parser::Variable>(&item.u)}) {
727       context.CheckIndexVarRedefine(*variable);
728     }
729   }
730 }
731 
732 void IoChecker::Leave(const parser::ReadStmt &readStmt) {
733   if (!flags_.test(Flag::InternalUnit)) {
734     CheckForPureSubprogram();
735   }
736   CheckForDoVariable(readStmt, context_);
737   if (!flags_.test(Flag::IoControlList)) {
738     Done();
739     return;
740   }
741   LeaveReadWrite();
742   CheckForProhibitedSpecifier(IoSpecKind::Delim); // C1212
743   CheckForProhibitedSpecifier(IoSpecKind::Sign); // C1212
744   CheckForProhibitedSpecifier(IoSpecKind::Rec, IoSpecKind::End); // C1220
745   CheckForRequiredSpecifier(IoSpecKind::Eor,
746       specifierSet_.test(IoSpecKind::Advance) && !flags_.test(Flag::AdvanceYes),
747       "ADVANCE with value 'NO'"); // C1222 + 12.6.2.1p2
748   CheckForRequiredSpecifier(IoSpecKind::Blank, flags_.test(Flag::FmtOrNml),
749       "FMT or NML"); // C1227
750   CheckForRequiredSpecifier(
751       IoSpecKind::Pad, flags_.test(Flag::FmtOrNml), "FMT or NML"); // C1227
752   Done();
753 }
754 
755 void IoChecker::Leave(const parser::RewindStmt &) {
756   CheckForRequiredSpecifier(
757       flags_.test(Flag::NumberUnit), "UNIT number"); // C1240
758   CheckForPureSubprogram();
759   Done();
760 }
761 
762 void IoChecker::Leave(const parser::WaitStmt &) {
763   CheckForRequiredSpecifier(
764       flags_.test(Flag::NumberUnit), "UNIT number"); // C1237
765   CheckForPureSubprogram();
766   Done();
767 }
768 
769 void IoChecker::Leave(const parser::WriteStmt &) {
770   if (!flags_.test(Flag::InternalUnit)) {
771     CheckForPureSubprogram();
772   }
773   LeaveReadWrite();
774   CheckForProhibitedSpecifier(IoSpecKind::Blank); // C1213
775   CheckForProhibitedSpecifier(IoSpecKind::End); // C1213
776   CheckForProhibitedSpecifier(IoSpecKind::Eor); // C1213
777   CheckForProhibitedSpecifier(IoSpecKind::Pad); // C1213
778   CheckForProhibitedSpecifier(IoSpecKind::Size); // C1213
779   CheckForRequiredSpecifier(
780       IoSpecKind::Sign, flags_.test(Flag::FmtOrNml), "FMT or NML"); // C1227
781   CheckForRequiredSpecifier(IoSpecKind::Delim,
782       flags_.test(Flag::StarFmt) || specifierSet_.test(IoSpecKind::Nml),
783       "FMT=* or NML"); // C1228
784   Done();
785 }
786 
787 void IoChecker::LeaveReadWrite() const {
788   CheckForRequiredSpecifier(IoSpecKind::Unit); // C1211
789   CheckForProhibitedSpecifier(IoSpecKind::Nml, IoSpecKind::Rec); // C1216
790   CheckForProhibitedSpecifier(IoSpecKind::Nml, IoSpecKind::Fmt); // C1216
791   CheckForProhibitedSpecifier(
792       IoSpecKind::Nml, flags_.test(Flag::DataList), "a data list"); // C1216
793   CheckForProhibitedSpecifier(flags_.test(Flag::InternalUnit),
794       "UNIT=internal-file", IoSpecKind::Pos); // C1219
795   CheckForProhibitedSpecifier(flags_.test(Flag::InternalUnit),
796       "UNIT=internal-file", IoSpecKind::Rec); // C1219
797   CheckForProhibitedSpecifier(
798       flags_.test(Flag::StarUnit), "UNIT=*", IoSpecKind::Pos); // C1219
799   CheckForProhibitedSpecifier(
800       flags_.test(Flag::StarUnit), "UNIT=*", IoSpecKind::Rec); // C1219
801   CheckForProhibitedSpecifier(
802       IoSpecKind::Rec, flags_.test(Flag::StarFmt), "FMT=*"); // C1220
803   CheckForRequiredSpecifier(IoSpecKind::Advance,
804       flags_.test(Flag::CharFmt) || flags_.test(Flag::LabelFmt) ||
805           flags_.test(Flag::AssignFmt),
806       "an explicit format"); // C1221
807   CheckForProhibitedSpecifier(IoSpecKind::Advance,
808       flags_.test(Flag::InternalUnit), "UNIT=internal-file"); // C1221
809   CheckForRequiredSpecifier(flags_.test(Flag::AsynchronousYes),
810       "ASYNCHRONOUS='YES'", flags_.test(Flag::NumberUnit),
811       "UNIT=number"); // C1224
812   CheckForRequiredSpecifier(IoSpecKind::Id, flags_.test(Flag::AsynchronousYes),
813       "ASYNCHRONOUS='YES'"); // C1225
814   CheckForProhibitedSpecifier(IoSpecKind::Pos, IoSpecKind::Rec); // C1226
815   CheckForRequiredSpecifier(IoSpecKind::Decimal, flags_.test(Flag::FmtOrNml),
816       "FMT or NML"); // C1227
817   CheckForRequiredSpecifier(IoSpecKind::Round, flags_.test(Flag::FmtOrNml),
818       "FMT or NML"); // C1227
819 }
820 
821 void IoChecker::SetSpecifier(IoSpecKind specKind) {
822   if (stmt_ == IoStmtKind::None) {
823     // FMT may appear on PRINT statements, which don't have any checks.
824     // [IO]MSG and [IO]STAT parse symbols are shared with non-I/O statements.
825     return;
826   }
827   // C1203, C1207, C1210, C1236, C1239, C1242, C1245
828   if (specifierSet_.test(specKind)) {
829     context_.Say("Duplicate %s specifier"_err_en_US,
830         parser::ToUpperCaseLetters(common::EnumToString(specKind)));
831   }
832   specifierSet_.set(specKind);
833 }
834 
835 void IoChecker::CheckStringValue(IoSpecKind specKind, const std::string &value,
836     const parser::CharBlock &source) const {
837   static std::unordered_map<IoSpecKind, const std::set<std::string>> specValues{
838       {IoSpecKind::Access, {"DIRECT", "SEQUENTIAL", "STREAM"}},
839       {IoSpecKind::Action, {"READ", "READWRITE", "WRITE"}},
840       {IoSpecKind::Advance, {"NO", "YES"}},
841       {IoSpecKind::Asynchronous, {"NO", "YES"}},
842       {IoSpecKind::Blank, {"NULL", "ZERO"}},
843       {IoSpecKind::Decimal, {"COMMA", "POINT"}},
844       {IoSpecKind::Delim, {"APOSTROPHE", "NONE", "QUOTE"}},
845       {IoSpecKind::Encoding, {"DEFAULT", "UTF-8"}},
846       {IoSpecKind::Form, {"FORMATTED", "UNFORMATTED"}},
847       {IoSpecKind::Pad, {"NO", "YES"}},
848       {IoSpecKind::Position, {"APPEND", "ASIS", "REWIND"}},
849       {IoSpecKind::Round,
850           {"COMPATIBLE", "DOWN", "NEAREST", "PROCESSOR_DEFINED", "UP", "ZERO"}},
851       {IoSpecKind::Sign, {"PLUS", "PROCESSOR_DEFINED", "SUPPRESS"}},
852       {IoSpecKind::Status,
853           // Open values; Close values are {"DELETE", "KEEP"}.
854           {"NEW", "OLD", "REPLACE", "SCRATCH", "UNKNOWN"}},
855       {IoSpecKind::Carriagecontrol, {"LIST", "FORTRAN", "NONE"}},
856       {IoSpecKind::Convert, {"BIG_ENDIAN", "LITTLE_ENDIAN", "NATIVE"}},
857       {IoSpecKind::Dispose, {"DELETE", "KEEP"}},
858   };
859   auto upper{parser::ToUpperCaseLetters(value)};
860   if (specValues.at(specKind).count(upper) == 0) {
861     if (specKind == IoSpecKind::Access && upper == "APPEND") {
862       if (context_.languageFeatures().ShouldWarn(
863               common::LanguageFeature::OpenAccessAppend)) {
864         context_.Say(source, "ACCESS='%s' interpreted as POSITION='%s'"_en_US,
865             value, upper);
866       }
867     } else {
868       context_.Say(source, "Invalid %s value '%s'"_err_en_US,
869           parser::ToUpperCaseLetters(common::EnumToString(specKind)), value);
870     }
871   }
872 }
873 
874 // CheckForRequiredSpecifier and CheckForProhibitedSpecifier functions
875 // need conditions to check, and string arguments to insert into a message.
876 // An IoSpecKind provides both an absence/presence condition and a string
877 // argument (its name).  A (condition, string) pair provides an arbitrary
878 // condition and an arbitrary string.
879 
880 void IoChecker::CheckForRequiredSpecifier(IoSpecKind specKind) const {
881   if (!specifierSet_.test(specKind)) {
882     context_.Say("%s statement must have a %s specifier"_err_en_US,
883         parser::ToUpperCaseLetters(common::EnumToString(stmt_)),
884         parser::ToUpperCaseLetters(common::EnumToString(specKind)));
885   }
886 }
887 
888 void IoChecker::CheckForRequiredSpecifier(
889     bool condition, const std::string &s) const {
890   if (!condition) {
891     context_.Say("%s statement must have a %s specifier"_err_en_US,
892         parser::ToUpperCaseLetters(common::EnumToString(stmt_)), s);
893   }
894 }
895 
896 void IoChecker::CheckForRequiredSpecifier(
897     IoSpecKind specKind1, IoSpecKind specKind2) const {
898   if (specifierSet_.test(specKind1) && !specifierSet_.test(specKind2)) {
899     context_.Say("If %s appears, %s must also appear"_err_en_US,
900         parser::ToUpperCaseLetters(common::EnumToString(specKind1)),
901         parser::ToUpperCaseLetters(common::EnumToString(specKind2)));
902   }
903 }
904 
905 void IoChecker::CheckForRequiredSpecifier(
906     IoSpecKind specKind, bool condition, const std::string &s) const {
907   if (specifierSet_.test(specKind) && !condition) {
908     context_.Say("If %s appears, %s must also appear"_err_en_US,
909         parser::ToUpperCaseLetters(common::EnumToString(specKind)), s);
910   }
911 }
912 
913 void IoChecker::CheckForRequiredSpecifier(
914     bool condition, const std::string &s, IoSpecKind specKind) const {
915   if (condition && !specifierSet_.test(specKind)) {
916     context_.Say("If %s appears, %s must also appear"_err_en_US, s,
917         parser::ToUpperCaseLetters(common::EnumToString(specKind)));
918   }
919 }
920 
921 void IoChecker::CheckForRequiredSpecifier(bool condition1,
922     const std::string &s1, bool condition2, const std::string &s2) const {
923   if (condition1 && !condition2) {
924     context_.Say("If %s appears, %s must also appear"_err_en_US, s1, s2);
925   }
926 }
927 
928 void IoChecker::CheckForProhibitedSpecifier(IoSpecKind specKind) const {
929   if (specifierSet_.test(specKind)) {
930     context_.Say("%s statement must not have a %s specifier"_err_en_US,
931         parser::ToUpperCaseLetters(common::EnumToString(stmt_)),
932         parser::ToUpperCaseLetters(common::EnumToString(specKind)));
933   }
934 }
935 
936 void IoChecker::CheckForProhibitedSpecifier(
937     IoSpecKind specKind1, IoSpecKind specKind2) const {
938   if (specifierSet_.test(specKind1) && specifierSet_.test(specKind2)) {
939     context_.Say("If %s appears, %s must not appear"_err_en_US,
940         parser::ToUpperCaseLetters(common::EnumToString(specKind1)),
941         parser::ToUpperCaseLetters(common::EnumToString(specKind2)));
942   }
943 }
944 
945 void IoChecker::CheckForProhibitedSpecifier(
946     IoSpecKind specKind, bool condition, const std::string &s) const {
947   if (specifierSet_.test(specKind) && condition) {
948     context_.Say("If %s appears, %s must not appear"_err_en_US,
949         parser::ToUpperCaseLetters(common::EnumToString(specKind)), s);
950   }
951 }
952 
953 void IoChecker::CheckForProhibitedSpecifier(
954     bool condition, const std::string &s, IoSpecKind specKind) const {
955   if (condition && specifierSet_.test(specKind)) {
956     context_.Say("If %s appears, %s must not appear"_err_en_US, s,
957         parser::ToUpperCaseLetters(common::EnumToString(specKind)));
958   }
959 }
960 
961 template <typename A>
962 void IoChecker::CheckForDefinableVariable(
963     const A &variable, const std::string &s) const {
964   if (const auto *var{parser::Unwrap<parser::Variable>(variable)}) {
965     if (auto expr{AnalyzeExpr(context_, *var)}) {
966       auto at{var->GetSource()};
967       if (auto whyNot{WhyNotModifiable(at, *expr, context_.FindScope(at),
968               true /*vectorSubscriptIsOk*/)}) {
969         const Symbol *base{GetFirstSymbol(*expr)};
970         context_
971             .Say(at, "%s variable '%s' must be definable"_err_en_US, s,
972                 (base ? base->name() : at).ToString())
973             .Attach(std::move(*whyNot));
974       }
975     }
976   }
977 }
978 
979 void IoChecker::CheckForPureSubprogram() const { // C1597
980   CHECK(context_.location());
981   if (const Scope *
982       scope{context_.globalScope().FindScope(*context_.location())}) {
983     if (FindPureProcedureContaining(*scope)) {
984       context_.Say(
985           "External I/O is not allowed in a pure subprogram"_err_en_US);
986     }
987   }
988 }
989 
990 } // namespace Fortran::semantics
991