semantics.h

//===-- include/flang/Semantics/semantics.h ---------------------*- C++ -*-===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
 
#ifndef FORTRAN_SEMANTICS_SEMANTICS_H_
#define FORTRAN_SEMANTICS_SEMANTICS_H_
 
#include "module-dependences.h"
#include "program-tree.h"
#include "scope.h"
#include "symbol.h"
#include "flang/Evaluate/common.h"
#include "flang/Evaluate/intrinsics.h"
#include "flang/Evaluate/target.h"
#include "flang/Parser/message.h"
#include "flang/Support/Fortran-features.h"
#include "flang/Support/LangOptions.h"
#include <set>
#include <string>
#include <vector>
 
namespace llvm {
class raw_ostream;
}
 
namespace Fortran::common {
class IntrinsicTypeDefaultKinds;
}
 
namespace Fortran::parser {
struct AccObject;
struct Name;
struct Program;
class AllCookedSources;
struct AssociateConstruct;
struct BlockConstruct;
struct CaseConstruct;
struct DoConstruct;
struct ChangeTeamConstruct;
struct CriticalConstruct;
struct ForallConstruct;
struct IfConstruct;
struct SelectRankConstruct;
struct SelectTypeConstruct;
struct Variable;
struct WhereConstruct;
} // namespace Fortran::parser
 
namespace Fortran::semantics {
 
class Symbol;
class CommonBlockMap;
using CommonBlockList = std::vector<std::pair<SymbolRef, std::size_t>>;
 
using ConstructNode = std::variant<const parser::AssociateConstruct *,
    const parser::BlockConstruct *, const parser::CaseConstruct *,
    const parser::ChangeTeamConstruct *, const parser::CriticalConstruct *,
    const parser::DoConstruct *, const parser::ForallConstruct *,
    const parser::IfConstruct *, const parser::SelectRankConstruct *,
    const parser::SelectTypeConstruct *, const parser::WhereConstruct *>;
using ConstructStack = std::vector<ConstructNode>;
 
class SemanticsContext {
public:
  SemanticsContext(const common::IntrinsicTypeDefaultKinds &,
      const common::LanguageFeatureControl &, const common::LangOptions &,
      parser::AllCookedSources &,
      common::FPMaxminBehavior = common::FPMaxminBehavior::Legacy);
  ~SemanticsContext();
 
  const common::IntrinsicTypeDefaultKinds &defaultKinds() const {
    return defaultKinds_;
  }
  const common::LanguageFeatureControl &languageFeatures() const {
    return languageFeatures_;
  }
  const common::LangOptions &langOptions() const { return langOpts_; }
  const std::string &openAccDefaultNoneScalarsStrictDisableOption() const {
    return openAccDefaultNoneScalarsStrictDisableOption_;
  }
  int GetDefaultKind(TypeCategory) const;
  int doublePrecisionKind() const {
    return defaultKinds_.doublePrecisionKind();
  }
  int quadPrecisionKind() const { return defaultKinds_.quadPrecisionKind(); }
  bool IsEnabled(common::LanguageFeature feature) const {
    return languageFeatures_.IsEnabled(feature);
  }
  template <typename A> bool ShouldWarn(A x) const {
    return languageFeatures_.ShouldWarn(x);
  }
  const std::optional<parser::CharBlock> &location() const { return location_; }
  const std::vector<std::string> &searchDirectories() const {
    return searchDirectories_;
  }
  const std::vector<std::string> &intrinsicModuleDirectories() const {
    return intrinsicModuleDirectories_;
  }
  const std::vector<std::string> &implicitUseModules() const {
    return implicitUseModules_;
  }
  const std::string &moduleDirectory() const { return moduleDirectory_; }
  const std::string &moduleFileSuffix() const { return moduleFileSuffix_; }
  bool underscoring() const { return underscoring_; }
  bool warningsAreErrors() const { return warningsAreErrors_; }
  bool debugModuleWriter() const { return debugModuleWriter_; }
  const evaluate::IntrinsicProcTable &intrinsics() const { return intrinsics_; }
  const evaluate::TargetCharacteristics &targetCharacteristics() const {
    return targetCharacteristics_;
  }
  evaluate::TargetCharacteristics &targetCharacteristics() {
    return targetCharacteristics_;
  }
  const std::string &targetTriple() const { return targetTriple_; }
  const std::string &targetFeatures() const { return targetFeatures_; }
  Scope &globalScope() { return globalScope_; }
  Scope &intrinsicModulesScope() { return intrinsicModulesScope_; }
  Scope *currentHermeticModuleFileScope() {
    return currentHermeticModuleFileScope_;
  }
  void set_currentHermeticModuleFileScope(Scope *scope) {
    currentHermeticModuleFileScope_ = scope;
  }
  parser::Messages &messages() { return messages_; }
  evaluate::FoldingContext &foldingContext() { return foldingContext_; }
  parser::AllCookedSources &allCookedSources() { return allCookedSources_; }
  ModuleDependences &moduleDependences() { return moduleDependences_; }
  std::map<const Symbol *, SourceName> &moduleFileOutputRenamings() {
    return moduleFileOutputRenamings_;
  }
 
  SemanticsContext &set_location(
      const std::optional<parser::CharBlock> &location) {
    location_ = location;
    return *this;
  }
  SemanticsContext &set_searchDirectories(const std::vector<std::string> &x) {
    searchDirectories_ = x;
    return *this;
  }
  SemanticsContext &set_intrinsicModuleDirectories(
      const std::vector<std::string> &x) {
    intrinsicModuleDirectories_ = x;
    return *this;
  }
  SemanticsContext &set_implicitUseModules(const std::vector<std::string> &x) {
    implicitUseModules_ = x;
    return *this;
  }
  SemanticsContext &set_moduleDirectory(const std::string &x) {
    moduleDirectory_ = x;
    return *this;
  }
  SemanticsContext &set_moduleFileSuffix(const std::string &x) {
    moduleFileSuffix_ = x;
    return *this;
  }
  SemanticsContext &set_underscoring(bool x) {
    underscoring_ = x;
    return *this;
  }
  SemanticsContext &set_warnOnNonstandardUsage(bool x) {
    warnOnNonstandardUsage_ = x;
    return *this;
  }
  SemanticsContext &set_maxErrors(size_t x) {
    maxErrors_ = x;
    return *this;
  }
  SemanticsContext &set_warningsAreErrors(bool x) {
    warningsAreErrors_ = x;
    return *this;
  }
  SemanticsContext &set_debugModuleWriter(bool x) {
    debugModuleWriter_ = x;
    return *this;
  }
  SemanticsContext &set_openAccDefaultNoneScalarsStrictDisableOption(
      std::string x) {
    openAccDefaultNoneScalarsStrictDisableOption_ = std::move(x);
    return *this;
  }
  SemanticsContext &set_targetTriple(const std::string &x) {
    targetTriple_ = x;
    return *this;
  }
  SemanticsContext &set_targetFeatures(const std::string &x) {
    targetFeatures_ = x;
    return *this;
  }
 
  const DeclTypeSpec &MakeNumericType(TypeCategory, int kind = 0);
  const DeclTypeSpec &MakeLogicalType(int kind = 0);
 
  std::size_t maxErrors() const { return maxErrors_; }
 
  bool AnyFatalError() const;
 
  // Test or set the Error flag on a Symbol
  bool HasError(const Symbol &);
  bool HasError(const Symbol *);
  bool HasError(const parser::Name &);
  void SetError(const Symbol &, bool = true);
 
  template <typename... A> parser::Message &Say(A &&...args) {
    CHECK(location_);
    return messages_.Say(*location_, std::forward<A>(args)...);
  }
  template <typename... A>
  parser::Message &Say(parser::CharBlock at, A &&...args) {
    return messages_.Say(at, std::forward<A>(args)...);
  }
  parser::Message &Say(parser::Message &&msg) {
    return messages_.Say(std::move(msg));
  }
  template <typename... A>
  parser::Message &SayWithDecl(const Symbol &symbol,
      const parser::CharBlock &at, parser::MessageFixedText &&msg,
      A &&...args) {
    auto &message{Say(at, std::move(msg), args...)};
    evaluate::AttachDeclaration(&message, symbol);
    return message;
  }
 
  template <typename... A>
  parser::Message *Warn(parser::Messages &messages,
      common::LanguageFeature feature, parser::CharBlock at, A &&...args) {
    return messages.Warn(IsInModuleFile(at), languageFeatures_, feature, at,
        std::forward<A>(args)...);
  }
  template <typename... A>
  parser::Message *Warn(parser::Messages &messages,
      common::UsageWarning warning, parser::CharBlock at, A &&...args) {
    return messages.Warn(IsInModuleFile(at), languageFeatures_, warning, at,
        std::forward<A>(args)...);
  }
  template <typename... A>
  parser::Message *Warn(parser::ContextualMessages &messages,
      common::LanguageFeature feature, parser::CharBlock at, A &&...args) {
    return messages.Warn(IsInModuleFile(at), languageFeatures_, feature, at,
        std::forward<A>(args)...);
  }
  template <typename... A>
  parser::Message *Warn(parser::ContextualMessages &messages,
      common::UsageWarning warning, parser::CharBlock at, A &&...args) {
    return messages.Warn(IsInModuleFile(at), languageFeatures_, warning, at,
        std::forward<A>(args)...);
  }
  template <typename... A>
  parser::Message *Warn(parser::ContextualMessages &messages,
      common::LanguageFeature feature, A &&...args) {
    return messages.Warn(IsInModuleFile(messages.at()), languageFeatures_,
        feature, messages.at(), std::forward<A>(args)...);
  }
  template <typename... A>
  parser::Message *Warn(parser::ContextualMessages &messages,
      common::UsageWarning warning, A &&...args) {
    return messages.Warn(IsInModuleFile(messages.at()), languageFeatures_,
        warning, messages.at(), std::forward<A>(args)...);
  }
  template <typename... A>
  parser::Message *Warn(
      common::LanguageFeature feature, parser::CharBlock at, A &&...args) {
    return Warn(messages_, feature, at, std::forward<A>(args)...);
  }
  template <typename... A>
  parser::Message *Warn(
      common::UsageWarning warning, parser::CharBlock at, A &&...args) {
    return Warn(messages_, warning, at, std::forward<A>(args)...);
  }
  template <typename... A>
  parser::Message *Warn(common::LanguageFeature feature, A &&...args) {
    CHECK(location_);
    return Warn(feature, *location_, std::forward<A>(args)...);
  }
  template <typename... A>
  parser::Message *Warn(common::UsageWarning warning, A &&...args) {
    CHECK(location_);
    return Warn(warning, *location_, std::forward<A>(args)...);
  }
 
  void EmitMessages(llvm::raw_ostream &);
 
  const Scope &FindScope(parser::CharBlock) const;
  Scope &FindScope(parser::CharBlock);
  void UpdateScopeIndex(Scope &, parser::CharBlock);
  void DumpScopeIndex(llvm::raw_ostream &) const;
 
  bool IsInModuleFile(parser::CharBlock) const;
 
  const ConstructStack &constructStack() const { return constructStack_; }
  template <typename N> void PushConstruct(const N &node) {
    constructStack_.emplace_back(&node);
  }
  void PopConstruct();
 
  ENUM_CLASS(IndexVarKind, DO, FORALL)
  // Check to see if a variable being redefined is a DO or FORALL index.
  // If so, emit a message.
  void WarnIndexVarRedefine(const parser::CharBlock &, const Symbol &);
  void CheckIndexVarRedefine(const parser::CharBlock &, const Symbol &);
  void CheckIndexVarRedefine(const parser::Variable &);
  void CheckIndexVarRedefine(const parser::Name &);
  void ActivateIndexVar(const parser::Name &, IndexVarKind);
  void DeactivateIndexVar(const parser::Name &);
  SymbolVector GetIndexVars(IndexVarKind);
  SourceName SaveTempName(std::string &&);
  SourceName GetTempName(const Scope &);
  static bool IsTempName(const std::string &);
 
  // Locate and process the contents of a built-in module on demand
  Scope *GetBuiltinModule(const char *name);
 
  // Defines builtinsScope_ from the __Fortran_builtins module
  void UseFortranBuiltinsModule();
  const Scope *GetBuiltinsScope() const { return builtinsScope_; }
 
  // Locate CUDA intrinsic modules on demand. These return null after emitting a
  // diagnostic when the required module file cannot be read.
  const Scope *GetCUDABuiltinsScope();
  const Scope *GetCUDADeviceScope();
 
  void UsePPCBuiltinTypesModule();
  void UsePPCBuiltinsModule();
  Scope *GetPPCBuiltinTypesScope() { return ppcBuiltinTypesScope_; }
  const Scope *GetPPCBuiltinsScope() const { return ppcBuiltinsScope_; }
 
  // Saves a module file's parse tree so that it remains available
  // during semantics.
  parser::Program &SaveParseTree(parser::Program &&);
 
  // Ensures a common block definition does not conflict with previous
  // appearances in the program and consolidate information about
  // common blocks at the program level for later checks and lowering.
  // This can obviously not check any conflicts between different compilation
  // units (in case such conflicts exist, the behavior will depend on the
  // linker).
  void MapCommonBlockAndCheckConflicts(const Symbol &);
 
  // After DATA statement initializations have been compiled into
  // symbol initializer values, check any pending conflicts recorded by
  // MapCommonBlockAndCheckConflicts() that could not be resolved earlier
  // because the initializer values were not yet known: a duplicate
  // initialization (identical values) of a COMMON block appearing in more
  // than one program unit is accepted as an extension, but a conflicting
  // one is a hard error.
  void CheckCommonBlockInitializationConflicts();
 
  // Get the list of common blocks appearing in the program. If a common block
  // appears in several subprograms, only one of its appearance is returned in
  // the list alongside the biggest byte size of all its appearances.
  // If a common block is initialized in any of its appearances, the list will
  // contain the appearance with the initialization, otherwise the appearance
  // with the biggest size is returned. The extra byte size information allows
  // handling the case where the common block initialization is not the
  // appearance with the biggest size: the common block will have the biggest
  // size with the first bytes initialized with the initial value. This is not
  // standard, if the initialization and biggest size appearances are in
  // different compilation units, the behavior will depend on the linker. The
  // linker may have the behavior described before, but it may also keep the
  // initialized common symbol without extending its size, or have some other
  // behavior.
  CommonBlockList GetCommonBlocks() const;
 
  void NoteDefinedSymbol(const Symbol &);
  bool IsSymbolDefined(const Symbol &) const;
  void NoteUsedSymbol(const Symbol &);
  void NoteUsedSymbols(const UnorderedSymbolSet &);
  bool IsSymbolUsed(const Symbol &) const;
 
  // Track same-kind duplicate AccObjects between resolve-directives and
  // rewrite-parse-tree (e.g. the second `x` in `private(x, x)`).
  void MarkAccObjectDuplicate(const parser::AccObject *o) {
    accObjectDuplicates_.insert(o);
  }
  bool IsAccObjectDuplicate(const parser::AccObject *o) const {
    return accObjectDuplicates_.count(o) != 0;
  }
 
  void DumpSymbols(llvm::raw_ostream &);
 
  // Top-level ProgramTrees are owned by the SemanticsContext for persistence.
  ProgramTree &SaveProgramTree(ProgramTree &&);
 
  const std::list<parser::Program> &GetModFileParseTrees() {
    return modFileParseTrees_;
  }
 
  // Label analysis classifies every labeled statement, and only some of those
  // classifications may be named by a statement that branches.  Lowering needs
  // the same distinction when it records the targets of a branch, so the
  // positions of the statements that may be branched to are kept here rather
  // than being derived a second time from the parse tree.
  void RecordBranchTarget(parser::CharBlock statementPosition) {
    branchTargets_.insert(statementPosition);
  }
 
  bool IsRecordedBranchTarget(parser::CharBlock statementPosition) const {
    return branchTargets_.find(statementPosition) != branchTargets_.end();
  }
 
private:
  struct ScopeIndexComparator {
    bool operator()(parser::CharBlock, parser::CharBlock) const;
  };
  using ScopeIndex =
      std::multimap<parser::CharBlock, Scope &, ScopeIndexComparator>;
  ScopeIndex::iterator SearchScopeIndex(parser::CharBlock);
 
  parser::Message *CheckIndexVarRedefine(
      const parser::CharBlock &, const Symbol &, parser::MessageFixedText &&);
  void CheckError(const Symbol &);
 
  std::set<parser::CharBlock, ScopeIndexComparator> branchTargets_;
  const common::IntrinsicTypeDefaultKinds &defaultKinds_;
  const common::LanguageFeatureControl &languageFeatures_;
  const common::LangOptions &langOpts_;
  parser::AllCookedSources &allCookedSources_;
  std::string openAccDefaultNoneScalarsStrictDisableOption_;
  std::optional<parser::CharBlock> location_;
  std::vector<std::string> searchDirectories_;
  std::vector<std::string> intrinsicModuleDirectories_;
  std::vector<std::string> implicitUseModules_;
  std::string moduleDirectory_{"."s};
  std::string moduleFileSuffix_{".mod"};
  std::string targetTriple_;
  std::string targetFeatures_;
  bool underscoring_{true};
  bool warnOnNonstandardUsage_{false};
  bool warningsAreErrors_{false};
  bool debugModuleWriter_{false};
  const evaluate::IntrinsicProcTable intrinsics_;
  evaluate::TargetCharacteristics targetCharacteristics_;
  Scope globalScope_;
  Scope &intrinsicModulesScope_;
  Scope *currentHermeticModuleFileScope_{nullptr};
  ScopeIndex scopeIndex_;
  parser::Messages messages_;
  std::size_t maxErrors_{0};
  evaluate::FoldingContext foldingContext_;
  ConstructStack constructStack_;
  struct IndexVarInfo {
    parser::CharBlock location;
    IndexVarKind kind;
  };
  std::map<SymbolRef, const IndexVarInfo, SymbolAddressCompare>
      activeIndexVars_;
  UnorderedSymbolSet errorSymbols_;
  std::set<std::string> tempNames_;
  const Scope *builtinsScope_{nullptr}; // module __Fortran_builtins
  Scope *ppcBuiltinTypesScope_{nullptr}; // module __Fortran_PPC_types
  std::optional<const Scope *> cudaBuiltinsScope_; // module __CUDA_builtins
  std::optional<const Scope *> cudaDeviceScope_; // module cudadevice
  const Scope *ppcBuiltinsScope_{nullptr}; // module __ppc_intrinsics
  std::list<parser::Program> modFileParseTrees_;
  std::unique_ptr<CommonBlockMap> commonBlockMap_;
  ModuleDependences moduleDependences_;
  std::map<const Symbol *, SourceName> moduleFileOutputRenamings_;
  UnorderedSymbolSet isDefined_;
  UnorderedSymbolSet isUsed_;
  std::set<const parser::AccObject *> accObjectDuplicates_;
  std::list<ProgramTree> programTrees_;
};
 
class Semantics {
public:
  explicit Semantics(SemanticsContext &context, parser::Program &program)
      : context_{context}, program_{program} {}
  Semantics &set_hermeticModuleFileOutput(bool yes = true) {
    hermeticModuleFileOutput_ = yes;
    return *this;
  }
 
  SemanticsContext &context() const { return context_; }
  bool Perform();
  const Scope &FindScope(const parser::CharBlock &where) const {
    return context_.FindScope(where);
  }
  bool AnyFatalError() const { return context_.AnyFatalError(); }
  void EmitMessages(llvm::raw_ostream &);
  void DumpSymbols(llvm::raw_ostream &);
  void DumpSymbolsSources(llvm::raw_ostream &) const;
 
private:
  SemanticsContext &context_;
  parser::Program &program_;
  bool hermeticModuleFileOutput_{false};
};
 
// Base class for semantics checkers.
struct BaseChecker {
  template <typename N> void Enter(const N &) {}
  template <typename N> void Leave(const N &) {}
};
} // namespace Fortran::semantics
#endif