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1//===-- PFTBuilder.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-exception6//7//===----------------------------------------------------------------------===//8 9#include "flang/Lower/PFTBuilder.h"10#include "flang/Lower/IntervalSet.h"11#include "flang/Lower/Support/Utils.h"12#include "flang/Parser/dump-parse-tree.h"13#include "flang/Parser/parse-tree-visitor.h"14#include "flang/Semantics/semantics.h"15#include "flang/Semantics/tools.h"16#include "llvm/ADT/DenseSet.h"17#include "llvm/ADT/IntervalMap.h"18#include "llvm/Support/CommandLine.h"19#include "llvm/Support/Debug.h"20 21#define DEBUG_TYPE "flang-pft"22 23static llvm::cl::opt<bool> clDisableStructuredFir(24    "no-structured-fir", llvm::cl::desc("disable generation of structured FIR"),25    llvm::cl::init(false), llvm::cl::Hidden);26 27using namespace Fortran;28 29namespace {30/// Helpers to unveil parser node inside Fortran::parser::Statement<>,31/// Fortran::parser::UnlabeledStatement, and Fortran::common::Indirection<>32template <typename A>33struct RemoveIndirectionHelper {34  using Type = A;35};36template <typename A>37struct RemoveIndirectionHelper<common::Indirection<A>> {38  using Type = A;39};40 41template <typename A>42struct UnwrapStmt {43  static constexpr bool isStmt{false};44};45template <typename A>46struct UnwrapStmt<parser::Statement<A>> {47  static constexpr bool isStmt{true};48  using Type = typename RemoveIndirectionHelper<A>::Type;49  constexpr UnwrapStmt(const parser::Statement<A> &a)50      : unwrapped{removeIndirection(a.statement)}, position{a.source},51        label{a.label} {}52  const Type &unwrapped;53  parser::CharBlock position;54  std::optional<parser::Label> label;55};56template <typename A>57struct UnwrapStmt<parser::UnlabeledStatement<A>> {58  static constexpr bool isStmt{true};59  using Type = typename RemoveIndirectionHelper<A>::Type;60  constexpr UnwrapStmt(const parser::UnlabeledStatement<A> &a)61      : unwrapped{removeIndirection(a.statement)}, position{a.source} {}62  const Type &unwrapped;63  parser::CharBlock position;64  std::optional<parser::Label> label;65};66 67#ifndef NDEBUG68void dumpScope(const semantics::Scope *scope, int depth = -1);69#endif70 71/// The instantiation of a parse tree visitor (Pre and Post) is extremely72/// expensive in terms of compile and link time. So one goal here is to73/// limit the bridge to one such instantiation.74class PFTBuilder {75public:76  PFTBuilder(const semantics::SemanticsContext &semanticsContext)77      : pgm{std::make_unique<lower::pft::Program>(78            semanticsContext.GetCommonBlocks())},79        semanticsContext{semanticsContext} {80    lower::pft::PftNode pftRoot{*pgm.get()};81    pftParentStack.push_back(pftRoot);82  }83 84  /// Get the result85  std::unique_ptr<lower::pft::Program> result() { return std::move(pgm); }86 87  template <typename A>88  constexpr bool Pre(const A &a) {89    if constexpr (lower::pft::isFunctionLike<A>) {90      return enterFunction(a, semanticsContext);91    } else if constexpr (lower::pft::isConstruct<A> ||92                         lower::pft::isDirective<A>) {93      return enterConstructOrDirective(a);94    } else if constexpr (UnwrapStmt<A>::isStmt) {95      using T = typename UnwrapStmt<A>::Type;96      // Node "a" being visited has one of the following types:97      // Statement<T>, Statement<Indirection<T>>, UnlabeledStatement<T>,98      // or UnlabeledStatement<Indirection<T>>99      auto stmt{UnwrapStmt<A>(a)};100      if constexpr (lower::pft::isConstructStmt<T> ||101                    lower::pft::isOtherStmt<T>) {102        addEvaluation(lower::pft::Evaluation{103            stmt.unwrapped, pftParentStack.back(), stmt.position, stmt.label});104        return false;105      } else if constexpr (std::is_same_v<T, parser::ActionStmt>) {106        return Fortran::common::visit(107            common::visitors{108                [&](const common::Indirection<parser::CallStmt> &x) {109                  addEvaluation(lower::pft::Evaluation{110                      removeIndirection(x), pftParentStack.back(),111                      stmt.position, stmt.label});112                  checkForFPEnvironmentCalls(x.value());113                  return true;114                },115                [&](const common::Indirection<parser::IfStmt> &x) {116                  convertIfStmt(x.value(), stmt.position, stmt.label);117                  return false;118                },119                [&](const auto &x) {120                  addEvaluation(lower::pft::Evaluation{121                      removeIndirection(x), pftParentStack.back(),122                      stmt.position, stmt.label});123                  return true;124                },125            },126            stmt.unwrapped.u);127      }128    }129    return true;130  }131 132  /// Check for calls that could modify the floating point environment.133  /// See F18 Clauses134  ///  - 17.1p3 (Overview of IEEE arithmetic support)135  ///  - 17.3p3 (The exceptions)136  ///  - 17.4p5 (The rounding modes)137  ///  - 17.6p1 (Halting)138  void checkForFPEnvironmentCalls(const parser::CallStmt &callStmt) {139    const auto *callName = std::get_if<parser::Name>(140        &std::get<parser::ProcedureDesignator>(callStmt.call.t).u);141    if (!callName)142      return;143    const Fortran::semantics::Symbol &procSym = callName->symbol->GetUltimate();144    if (!procSym.owner().IsModule())145      return;146    const Fortran::semantics::Symbol &modSym = *procSym.owner().symbol();147    if (!modSym.attrs().test(Fortran::semantics::Attr::INTRINSIC))148      return;149    // Modules IEEE_FEATURES, IEEE_EXCEPTIONS, and IEEE_ARITHMETIC get common150    // declarations from several __fortran_... support module files.151    llvm::StringRef modName = toStringRef(modSym.name());152    if (!modName.starts_with("ieee_") && !modName.starts_with("__fortran_"))153      return;154    llvm::StringRef procName = toStringRef(procSym.name());155    if (!procName.starts_with("ieee_"))156      return;157    lower::pft::FunctionLikeUnit *proc =158        evaluationListStack.back()->back().getOwningProcedure();159    proc->hasIeeeAccess = true;160    if (!procName.starts_with("ieee_set_"))161      return;162    if (procName.starts_with("ieee_set_modes_") ||163        procName.starts_with("ieee_set_status_"))164      proc->mayModifyHaltingMode = proc->mayModifyRoundingMode =165          proc->mayModifyUnderflowMode = true;166    else if (procName.starts_with("ieee_set_halting_mode_"))167      proc->mayModifyHaltingMode = true;168    else if (procName.starts_with("ieee_set_rounding_mode_"))169      proc->mayModifyRoundingMode = true;170    else if (procName.starts_with("ieee_set_underflow_mode_"))171      proc->mayModifyUnderflowMode = true;172  }173 174  /// Convert an IfStmt into an IfConstruct, retaining the IfStmt as the175  /// first statement of the construct.176  void convertIfStmt(const parser::IfStmt &ifStmt, parser::CharBlock position,177                     std::optional<parser::Label> label) {178    // Generate a skeleton IfConstruct parse node. Its components are never179    // referenced. The actual components are available via the IfConstruct180    // evaluation's nested evaluationList, with the ifStmt in the position of181    // the otherwise normal IfThenStmt. Caution: All other PFT nodes reference182    // front end generated parse nodes; this is an exceptional case.183    static const auto ifConstruct = parser::IfConstruct{184        parser::Statement<parser::IfThenStmt>{185            std::nullopt,186            parser::IfThenStmt{187                std::optional<parser::Name>{},188                parser::ScalarLogicalExpr{parser::LogicalExpr{parser::Expr{189                    parser::LiteralConstant{parser::LogicalLiteralConstant{190                        false, std::optional<parser::KindParam>{}}}}}}}},191        parser::Block{}, std::list<parser::IfConstruct::ElseIfBlock>{},192        std::optional<parser::IfConstruct::ElseBlock>{},193        parser::Statement<parser::EndIfStmt>{std::nullopt,194                                             parser::EndIfStmt{std::nullopt}}};195    enterConstructOrDirective(ifConstruct);196    addEvaluation(197        lower::pft::Evaluation{ifStmt, pftParentStack.back(), position, label});198    Pre(std::get<parser::UnlabeledStatement<parser::ActionStmt>>(ifStmt.t));199    static const auto endIfStmt = parser::EndIfStmt{std::nullopt};200    addEvaluation(201        lower::pft::Evaluation{endIfStmt, pftParentStack.back(), {}, {}});202    exitConstructOrDirective();203  }204 205  template <typename A>206  constexpr void Post(const A &) {207    if constexpr (lower::pft::isFunctionLike<A>) {208      exitFunction();209    } else if constexpr (lower::pft::isConstruct<A> ||210                         lower::pft::isDirective<A>) {211      exitConstructOrDirective();212    }213  }214 215  bool Pre(const parser::SpecificationPart &) {216    ++specificationPartLevel;217    return true;218  }219  void Post(const parser::SpecificationPart &) { --specificationPartLevel; }220 221  bool Pre(const parser::ContainsStmt &) {222    if (!specificationPartLevel) {223      assert(containsStmtStack.size() && "empty contains stack");224      containsStmtStack.back() = true;225    }226    return false;227  }228 229  // Module like230  bool Pre(const parser::Module &node) { return enterModule(node); }231  bool Pre(const parser::Submodule &node) { return enterModule(node); }232 233  void Post(const parser::Module &) { exitModule(); }234  void Post(const parser::Submodule &) { exitModule(); }235 236  // Block data237  bool Pre(const parser::BlockData &node) {238    addUnit(lower::pft::BlockDataUnit{node, pftParentStack.back(),239                                      semanticsContext});240    return false;241  }242 243  // Get rid of production wrapper244  bool Pre(const parser::Statement<parser::ForallAssignmentStmt> &statement) {245    addEvaluation(Fortran::common::visit(246        [&](const auto &x) {247          return lower::pft::Evaluation{x, pftParentStack.back(),248                                        statement.source, statement.label};249        },250        statement.statement.u));251    return false;252  }253  bool Pre(const parser::WhereBodyConstruct &whereBody) {254    return Fortran::common::visit(255        common::visitors{256            [&](const parser::Statement<parser::AssignmentStmt> &stmt) {257              // Not caught as other AssignmentStmt because it is not258              // wrapped in a parser::ActionStmt.259              addEvaluation(lower::pft::Evaluation{stmt.statement,260                                                   pftParentStack.back(),261                                                   stmt.source, stmt.label});262              return false;263            },264            [&](const auto &) { return true; },265        },266        whereBody.u);267  }268 269  // A CompilerDirective may appear outside any program unit, after a module270  // or function contains statement, or inside a module or function.271  bool Pre(const parser::CompilerDirective &directive) {272    assert(pftParentStack.size() > 0 && "no program");273    lower::pft::PftNode &node = pftParentStack.back();274    if (node.isA<lower::pft::Program>()) {275      addUnit(lower::pft::CompilerDirectiveUnit(directive, node));276      return false;277    } else if ((node.isA<lower::pft::ModuleLikeUnit>() ||278                node.isA<lower::pft::FunctionLikeUnit>())) {279      assert(containsStmtStack.size() && "empty contains stack");280      if (containsStmtStack.back()) {281        addContainedUnit(lower::pft::CompilerDirectiveUnit{directive, node});282        return false;283      }284    }285    return enterConstructOrDirective(directive);286  }287 288  bool Pre(const parser::OpenACCRoutineConstruct &directive) {289    assert(pftParentStack.size() > 0 &&290           "At least the Program must be a parent");291    if (pftParentStack.back().isA<lower::pft::Program>()) {292      addUnit(293          lower::pft::OpenACCDirectiveUnit(directive, pftParentStack.back()));294      return false;295    }296    return enterConstructOrDirective(directive);297  }298 299private:300  /// Initialize a new module-like unit and make it the builder's focus.301  template <typename A>302  bool enterModule(const A &mod) {303    lower::pft::ModuleLikeUnit &unit =304        addUnit(lower::pft::ModuleLikeUnit{mod, pftParentStack.back()});305    containsStmtStack.push_back(false);306    containedUnitList = &unit.containedUnitList;307    pushEvaluationList(&unit.evaluationList);308    pftParentStack.emplace_back(unit);309    LLVM_DEBUG(dumpScope(&unit.getScope()));310    return true;311  }312 313  void exitModule() {314    containsStmtStack.pop_back();315    if (!evaluationListStack.empty())316      popEvaluationList();317    pftParentStack.pop_back();318    resetFunctionState();319  }320 321  /// Add the end statement Evaluation of a sub/program to the PFT.322  /// There may be intervening internal subprogram definitions between323  /// prior statements and this end statement.324  void endFunctionBody() {325    if (evaluationListStack.empty())326      return;327    auto evaluationList = evaluationListStack.back();328    if (evaluationList->empty() || !evaluationList->back().isEndStmt()) {329      const auto &endStmt =330          pftParentStack.back().get<lower::pft::FunctionLikeUnit>().endStmt;331      endStmt.visit(common::visitors{332          [&](const parser::Statement<parser::EndProgramStmt> &s) {333            addEvaluation(lower::pft::Evaluation{334                s.statement, pftParentStack.back(), s.source, s.label});335          },336          [&](const parser::Statement<parser::EndFunctionStmt> &s) {337            addEvaluation(lower::pft::Evaluation{338                s.statement, pftParentStack.back(), s.source, s.label});339          },340          [&](const parser::Statement<parser::EndSubroutineStmt> &s) {341            addEvaluation(lower::pft::Evaluation{342                s.statement, pftParentStack.back(), s.source, s.label});343          },344          [&](const parser::Statement<parser::EndMpSubprogramStmt> &s) {345            addEvaluation(lower::pft::Evaluation{346                s.statement, pftParentStack.back(), s.source, s.label});347          },348          [&](const auto &s) {349            llvm::report_fatal_error("missing end statement or unexpected "350                                     "begin statement reference");351          },352      });353    }354    lastLexicalEvaluation = nullptr;355  }356 357  /// Pop the ModuleLikeUnit evaluationList when entering the first module358  /// procedure.359  void cleanModuleEvaluationList() {360    if (evaluationListStack.empty())361      return;362    if (pftParentStack.back().isA<lower::pft::ModuleLikeUnit>())363      popEvaluationList();364  }365 366  /// Initialize a new function-like unit and make it the builder's focus.367  template <typename A>368  bool enterFunction(const A &func,369                     const semantics::SemanticsContext &semanticsContext) {370    cleanModuleEvaluationList();371    endFunctionBody(); // enclosing host subprogram body, if any372    lower::pft::FunctionLikeUnit &unit =373        addContainedUnit(lower::pft::FunctionLikeUnit{374            func, pftParentStack.back(), semanticsContext});375    labelEvaluationMap = &unit.labelEvaluationMap;376    assignSymbolLabelMap = &unit.assignSymbolLabelMap;377    containsStmtStack.push_back(false);378    containedUnitList = &unit.containedUnitList;379    pushEvaluationList(&unit.evaluationList);380    pftParentStack.emplace_back(unit);381    LLVM_DEBUG(dumpScope(&unit.getScope()));382    return true;383  }384 385  void exitFunction() {386    rewriteIfGotos();387    endFunctionBody();388    analyzeBranches(nullptr, *evaluationListStack.back()); // add branch links389    processEntryPoints();390    containsStmtStack.pop_back();391    popEvaluationList();392    labelEvaluationMap = nullptr;393    assignSymbolLabelMap = nullptr;394    pftParentStack.pop_back();395    resetFunctionState();396  }397 398  /// Initialize a new construct or directive and make it the builder's focus.399  template <typename A>400  bool enterConstructOrDirective(const A &constructOrDirective) {401    lower::pft::Evaluation &eval = addEvaluation(402        lower::pft::Evaluation{constructOrDirective, pftParentStack.back()});403    eval.evaluationList.reset(new lower::pft::EvaluationList);404    pushEvaluationList(eval.evaluationList.get());405    pftParentStack.emplace_back(eval);406    constructAndDirectiveStack.emplace_back(&eval);407    return true;408  }409 410  void exitConstructOrDirective() {411    auto isOpenMPLoopConstruct = [](lower::pft::Evaluation *eval) {412      if (const auto *ompConstruct = eval->getIf<parser::OpenMPConstruct>())413        if (std::holds_alternative<parser::OpenMPLoopConstruct>(414                ompConstruct->u))415          return true;416      return false;417    };418 419    rewriteIfGotos();420    auto *eval = constructAndDirectiveStack.back();421    if (eval->isExecutableDirective() && !isOpenMPLoopConstruct(eval)) {422      // A construct at the end of an (unstructured) OpenACC or OpenMP423      // construct region must have an exit target inside the region.424      // This is not applicable to the OpenMP loop construct since the425      // end of the loop is an available target inside the region.426      lower::pft::EvaluationList &evaluationList = *eval->evaluationList;427      if (!evaluationList.empty() && evaluationList.back().isConstruct()) {428        static const parser::ContinueStmt exitTarget{};429        addEvaluation(430            lower::pft::Evaluation{exitTarget, pftParentStack.back(), {}, {}});431      }432    }433    popEvaluationList();434    pftParentStack.pop_back();435    constructAndDirectiveStack.pop_back();436  }437 438  /// Reset function state to that of an enclosing host function.439  void resetFunctionState() {440    if (!pftParentStack.empty()) {441      pftParentStack.back().visit(common::visitors{442          [&](lower::pft::ModuleLikeUnit &p) {443            containedUnitList = &p.containedUnitList;444          },445          [&](lower::pft::FunctionLikeUnit &p) {446            containedUnitList = &p.containedUnitList;447            labelEvaluationMap = &p.labelEvaluationMap;448            assignSymbolLabelMap = &p.assignSymbolLabelMap;449          },450          [&](auto &) { containedUnitList = nullptr; },451      });452    }453  }454 455  template <typename A>456  A &addUnit(A &&unit) {457    pgm->getUnits().emplace_back(std::move(unit));458    return std::get<A>(pgm->getUnits().back());459  }460 461  template <typename A>462  A &addContainedUnit(A &&unit) {463    if (!containedUnitList)464      return addUnit(std::move(unit));465    containedUnitList->emplace_back(std::move(unit));466    return std::get<A>(containedUnitList->back());467  }468 469  // ActionStmt has a couple of non-conforming cases, explicitly handled here.470  // The other cases use an Indirection, which are discarded in the PFT.471  lower::pft::Evaluation472  makeEvaluationAction(const parser::ActionStmt &statement,473                       parser::CharBlock position,474                       std::optional<parser::Label> label) {475    return Fortran::common::visit(476        common::visitors{477            [&](const auto &x) {478              return lower::pft::Evaluation{479                  removeIndirection(x), pftParentStack.back(), position, label};480            },481        },482        statement.u);483  }484 485  /// Append an Evaluation to the end of the current list.486  lower::pft::Evaluation &addEvaluation(lower::pft::Evaluation &&eval) {487    assert(!evaluationListStack.empty() && "empty evaluation list stack");488    if (!constructAndDirectiveStack.empty())489      eval.parentConstruct = constructAndDirectiveStack.back();490    lower::pft::FunctionLikeUnit *owningProcedure = eval.getOwningProcedure();491    evaluationListStack.back()->emplace_back(std::move(eval));492    lower::pft::Evaluation *p = &evaluationListStack.back()->back();493    if (p->isActionStmt() || p->isConstructStmt() || p->isEndStmt() ||494        p->isExecutableDirective()) {495      if (lastLexicalEvaluation) {496        lastLexicalEvaluation->lexicalSuccessor = p;497        p->printIndex = lastLexicalEvaluation->printIndex + 1;498      } else {499        p->printIndex = 1;500      }501      lastLexicalEvaluation = p;502      if (owningProcedure) {503        auto &entryPointList = owningProcedure->entryPointList;504        for (std::size_t entryIndex = entryPointList.size() - 1;505             entryIndex && !entryPointList[entryIndex].second->lexicalSuccessor;506             --entryIndex)507          // Link to the entry's first executable statement.508          entryPointList[entryIndex].second->lexicalSuccessor = p;509      }510    } else if (const auto *entryStmt = p->getIf<parser::EntryStmt>()) {511      const semantics::Symbol *sym =512          std::get<parser::Name>(entryStmt->t).symbol;513      if (auto *details = sym->detailsIf<semantics::GenericDetails>())514        sym = details->specific();515      assert(sym->has<semantics::SubprogramDetails>() &&516             "entry must be a subprogram");517      owningProcedure->entryPointList.push_back(std::pair{sym, p});518    }519    if (p->label.has_value())520      labelEvaluationMap->try_emplace(*p->label, p);521    return evaluationListStack.back()->back();522  }523 524  /// push a new list on the stack of Evaluation lists525  void pushEvaluationList(lower::pft::EvaluationList *evaluationList) {526    assert(evaluationList && evaluationList->empty() &&527           "invalid evaluation list");528    evaluationListStack.emplace_back(evaluationList);529  }530 531  /// pop the current list and return to the last Evaluation list532  void popEvaluationList() {533    assert(!evaluationListStack.empty() &&534           "trying to pop an empty evaluationListStack");535    evaluationListStack.pop_back();536  }537 538  /// Rewrite IfConstructs containing a GotoStmt or CycleStmt to eliminate an539  /// unstructured branch and a trivial basic block. The pre-branch-analysis540  /// code:541  ///542  ///       <<IfConstruct>>543  ///         1 If[Then]Stmt: if(cond) goto L544  ///         2 GotoStmt: goto L545  ///         3 EndIfStmt546  ///       <<End IfConstruct>>547  ///       4 Statement: ...548  ///       5 Statement: ...549  ///       6 Statement: L ...550  ///551  /// becomes:552  ///553  ///       <<IfConstruct>>554  ///         1 If[Then]Stmt [negate]: if(cond) goto L555  ///         4 Statement: ...556  ///         5 Statement: ...557  ///         3 EndIfStmt558  ///       <<End IfConstruct>>559  ///       6 Statement: L ...560  ///561  /// The If[Then]Stmt condition is implicitly negated. It is not modified562  /// in the PFT. It must be negated when generating FIR. The GotoStmt or563  /// CycleStmt is deleted.564  ///565  /// The transformation is only valid for forward branch targets at the same566  /// construct nesting level as the IfConstruct. The result must not violate567  /// construct nesting requirements or contain an EntryStmt. The result568  /// is subject to normal un/structured code classification analysis. Except569  /// for a branch to the EndIfStmt, the result is allowed to violate the F18570  /// Clause 11.1.2.1 prohibition on transfer of control into the interior of571  /// a construct block, as that does not compromise correct code generation.572  /// When two transformation candidates overlap, at least one must be573  /// disallowed. In such cases, the current heuristic favors simple code574  /// generation, which happens to favor later candidates over earlier575  /// candidates. That choice is probably not significant, but could be576  /// changed.577  void rewriteIfGotos() {578    auto &evaluationList = *evaluationListStack.back();579    if (!evaluationList.size())580      return;581    struct T {582      lower::pft::EvaluationList::iterator ifConstructIt;583      parser::Label ifTargetLabel;584      bool isCycleStmt = false;585    };586    llvm::SmallVector<T> ifCandidateStack;587    const auto *doStmt =588        evaluationList.begin()->getIf<parser::NonLabelDoStmt>();589    std::string doName = doStmt ? getConstructName(*doStmt) : std::string{};590    for (auto it = evaluationList.begin(), end = evaluationList.end();591         it != end; ++it) {592      auto &eval = *it;593      if (eval.isA<parser::EntryStmt>() || eval.isIntermediateConstructStmt()) {594        ifCandidateStack.clear();595        continue;596      }597      auto firstStmt = [](lower::pft::Evaluation *e) {598        return e->isConstruct() ? &*e->evaluationList->begin() : e;599      };600      const Fortran::lower::pft::Evaluation &targetEval = *firstStmt(&eval);601      bool targetEvalIsEndDoStmt = targetEval.isA<parser::EndDoStmt>();602      auto branchTargetMatch = [&]() {603        if (const parser::Label targetLabel =604                ifCandidateStack.back().ifTargetLabel)605          if (targetEval.label && targetLabel == *targetEval.label)606            return true; // goto target match607        if (targetEvalIsEndDoStmt && ifCandidateStack.back().isCycleStmt)608          return true; // cycle target match609        return false;610      };611      if (targetEval.label || targetEvalIsEndDoStmt) {612        while (!ifCandidateStack.empty() && branchTargetMatch()) {613          lower::pft::EvaluationList::iterator ifConstructIt =614              ifCandidateStack.back().ifConstructIt;615          lower::pft::EvaluationList::iterator successorIt =616              std::next(ifConstructIt);617          if (successorIt != it) {618            Fortran::lower::pft::EvaluationList &ifBodyList =619                *ifConstructIt->evaluationList;620            lower::pft::EvaluationList::iterator branchStmtIt =621                std::next(ifBodyList.begin());622            assert((branchStmtIt->isA<parser::GotoStmt>() ||623                    branchStmtIt->isA<parser::CycleStmt>()) &&624                   "expected goto or cycle statement");625            ifBodyList.erase(branchStmtIt);626            lower::pft::Evaluation &ifStmt = *ifBodyList.begin();627            ifStmt.negateCondition = true;628            ifStmt.lexicalSuccessor = firstStmt(&*successorIt);629            lower::pft::EvaluationList::iterator endIfStmtIt =630                std::prev(ifBodyList.end());631            std::prev(it)->lexicalSuccessor = &*endIfStmtIt;632            endIfStmtIt->lexicalSuccessor = firstStmt(&*it);633            ifBodyList.splice(endIfStmtIt, evaluationList, successorIt, it);634            for (; successorIt != endIfStmtIt; ++successorIt)635              successorIt->parentConstruct = &*ifConstructIt;636          }637          ifCandidateStack.pop_back();638        }639      }640      if (eval.isA<parser::IfConstruct>() && eval.evaluationList->size() == 3) {641        const auto bodyEval = std::next(eval.evaluationList->begin());642        if (const auto *gotoStmt = bodyEval->getIf<parser::GotoStmt>()) {643          if (!bodyEval->lexicalSuccessor->label)644            ifCandidateStack.push_back({it, gotoStmt->v});645        } else if (doStmt) {646          if (const auto *cycleStmt = bodyEval->getIf<parser::CycleStmt>()) {647            std::string cycleName = getConstructName(*cycleStmt);648            if (cycleName.empty() || cycleName == doName)649              // This candidate will match doStmt's EndDoStmt.650              ifCandidateStack.push_back({it, {}, true});651          }652        }653      }654    }655  }656 657  /// Mark IO statement ERR, EOR, and END specifier branch targets.658  /// Mark an IO statement with an assigned format as unstructured.659  template <typename A>660  void analyzeIoBranches(lower::pft::Evaluation &eval, const A &stmt) {661    auto analyzeFormatSpec = [&](const parser::Format &format) {662      if (const auto *expr = std::get_if<parser::Expr>(&format.u)) {663        if (semantics::ExprHasTypeCategory(*semantics::GetExpr(*expr),664                                           common::TypeCategory::Integer))665          eval.isUnstructured = true;666      }667    };668    auto analyzeSpecs{[&](const auto &specList) {669      for (const auto &spec : specList) {670        Fortran::common::visit(671            Fortran::common::visitors{672                [&](const Fortran::parser::Format &format) {673                  analyzeFormatSpec(format);674                },675                [&](const auto &label) {676                  using LabelNodes =677                      std::tuple<parser::ErrLabel, parser::EorLabel,678                                 parser::EndLabel>;679                  if constexpr (common::HasMember<decltype(label), LabelNodes>)680                    markBranchTarget(eval, label.v);681                }},682            spec.u);683      }684    }};685 686    using OtherIOStmts =687        std::tuple<parser::BackspaceStmt, parser::CloseStmt,688                   parser::EndfileStmt, parser::FlushStmt, parser::OpenStmt,689                   parser::RewindStmt, parser::WaitStmt>;690 691    if constexpr (std::is_same_v<A, parser::ReadStmt> ||692                  std::is_same_v<A, parser::WriteStmt>) {693      if (stmt.format)694        analyzeFormatSpec(*stmt.format);695      analyzeSpecs(stmt.controls);696    } else if constexpr (std::is_same_v<A, parser::PrintStmt>) {697      analyzeFormatSpec(std::get<parser::Format>(stmt.t));698    } else if constexpr (std::is_same_v<A, parser::InquireStmt>) {699      if (const auto *specList =700              std::get_if<std::list<parser::InquireSpec>>(&stmt.u))701        analyzeSpecs(*specList);702    } else if constexpr (common::HasMember<A, OtherIOStmts>) {703      analyzeSpecs(stmt.v);704    } else {705      // Always crash if this is instantiated706      static_assert(!std::is_same_v<A, parser::ReadStmt>,707                    "Unexpected IO statement");708    }709  }710 711  /// Set the exit of a construct, possibly from multiple enclosing constructs.712  void setConstructExit(lower::pft::Evaluation &eval) {713    eval.constructExit = &eval.evaluationList->back().nonNopSuccessor();714  }715 716  /// Mark the target of a branch as a new block.717  void markBranchTarget(lower::pft::Evaluation &sourceEvaluation,718                        lower::pft::Evaluation &targetEvaluation) {719    sourceEvaluation.isUnstructured = true;720    if (!sourceEvaluation.controlSuccessor)721      sourceEvaluation.controlSuccessor = &targetEvaluation;722    targetEvaluation.isNewBlock = true;723    // If this is a branch into the body of a construct (usually illegal,724    // but allowed in some legacy cases), then the targetEvaluation and its725    // ancestors must be marked as unstructured.726    lower::pft::Evaluation *sourceConstruct = sourceEvaluation.parentConstruct;727    lower::pft::Evaluation *targetConstruct = targetEvaluation.parentConstruct;728    if (targetConstruct &&729        &targetConstruct->getFirstNestedEvaluation() == &targetEvaluation)730      // A branch to an initial constructStmt is a branch to the construct.731      targetConstruct = targetConstruct->parentConstruct;732    if (targetConstruct) {733      while (sourceConstruct && sourceConstruct != targetConstruct)734        sourceConstruct = sourceConstruct->parentConstruct;735      if (sourceConstruct != targetConstruct) // branch into a construct body736        for (lower::pft::Evaluation *eval = &targetEvaluation; eval;737             eval = eval->parentConstruct) {738          eval->isUnstructured = true;739          // If the branch is a backward branch into an already analyzed740          // DO or IF construct, mark the construct exit as a new block.741          // For a forward branch, the isUnstructured flag will cause this742          // to be done when the construct is analyzed.743          if (eval->constructExit && (eval->isA<parser::DoConstruct>() ||744                                      eval->isA<parser::IfConstruct>()))745            eval->constructExit->isNewBlock = true;746        }747    }748  }749  void markBranchTarget(lower::pft::Evaluation &sourceEvaluation,750                        parser::Label label) {751    assert(label && "missing branch target label");752    lower::pft::Evaluation *targetEvaluation{753        labelEvaluationMap->find(label)->second};754    assert(targetEvaluation && "missing branch target evaluation");755    markBranchTarget(sourceEvaluation, *targetEvaluation);756  }757 758  /// Mark the successor of an Evaluation as a new block.759  void markSuccessorAsNewBlock(lower::pft::Evaluation &eval) {760    eval.nonNopSuccessor().isNewBlock = true;761  }762 763  template <typename A>764  inline std::string getConstructName(const A &stmt) {765    using MaybeConstructNameWrapper =766        std::tuple<parser::BlockStmt, parser::CycleStmt, parser::ElseStmt,767                   parser::ElsewhereStmt, parser::EndAssociateStmt,768                   parser::EndBlockStmt, parser::EndCriticalStmt,769                   parser::EndDoStmt, parser::EndForallStmt, parser::EndIfStmt,770                   parser::EndSelectStmt, parser::EndWhereStmt,771                   parser::ExitStmt>;772    if constexpr (common::HasMember<A, MaybeConstructNameWrapper>) {773      if (stmt.v)774        return stmt.v->ToString();775    }776 777    using MaybeConstructNameInTuple = std::tuple<778        parser::AssociateStmt, parser::CaseStmt, parser::ChangeTeamStmt,779        parser::CriticalStmt, parser::ElseIfStmt, parser::EndChangeTeamStmt,780        parser::ForallConstructStmt, parser::IfThenStmt, parser::LabelDoStmt,781        parser::MaskedElsewhereStmt, parser::NonLabelDoStmt,782        parser::SelectCaseStmt, parser::SelectRankCaseStmt,783        parser::TypeGuardStmt, parser::WhereConstructStmt>;784    if constexpr (common::HasMember<A, MaybeConstructNameInTuple>) {785      if (auto name = std::get<std::optional<parser::Name>>(stmt.t))786        return name->ToString();787    }788 789    // These statements have multiple std::optional<parser::Name> elements.790    if constexpr (std::is_same_v<A, parser::SelectRankStmt> ||791                  std::is_same_v<A, parser::SelectTypeStmt>) {792      if (auto name = std::get<0>(stmt.t))793        return name->ToString();794    }795 796    return {};797  }798 799  /// \p parentConstruct can be null if this statement is at the highest800  /// level of a program.801  template <typename A>802  void insertConstructName(const A &stmt,803                           lower::pft::Evaluation *parentConstruct) {804    std::string name = getConstructName(stmt);805    if (!name.empty())806      constructNameMap[name] = parentConstruct;807  }808 809  /// Insert branch links for a list of Evaluations.810  /// \p parentConstruct can be null if the evaluationList contains the811  /// top-level statements of a program.812  void analyzeBranches(lower::pft::Evaluation *parentConstruct,813                       std::list<lower::pft::Evaluation> &evaluationList) {814    lower::pft::Evaluation *lastConstructStmtEvaluation{};815    for (auto &eval : evaluationList) {816      eval.visit(common::visitors{817          // Action statements (except IO statements)818          [&](const parser::CallStmt &s) {819            // Look for alternate return specifiers.820            const auto &args =821                std::get<std::list<parser::ActualArgSpec>>(s.call.t);822            for (const auto &arg : args) {823              const auto &actual = std::get<parser::ActualArg>(arg.t);824              if (const auto *altReturn =825                      std::get_if<parser::AltReturnSpec>(&actual.u))826                markBranchTarget(eval, altReturn->v);827            }828          },829          [&](const parser::CycleStmt &s) {830            std::string name = getConstructName(s);831            lower::pft::Evaluation *construct{name.empty()832                                                  ? doConstructStack.back()833                                                  : constructNameMap[name]};834            assert(construct && "missing CYCLE construct");835            markBranchTarget(eval, construct->evaluationList->back());836          },837          [&](const parser::ExitStmt &s) {838            std::string name = getConstructName(s);839            lower::pft::Evaluation *construct{name.empty()840                                                  ? doConstructStack.back()841                                                  : constructNameMap[name]};842            assert(construct && "missing EXIT construct");843            markBranchTarget(eval, *construct->constructExit);844          },845          [&](const parser::FailImageStmt &) {846            eval.isUnstructured = true;847            if (eval.lexicalSuccessor->lexicalSuccessor)848              markSuccessorAsNewBlock(eval);849          },850          [&](const parser::GotoStmt &s) { markBranchTarget(eval, s.v); },851          [&](const parser::IfStmt &) {852            eval.lexicalSuccessor->isNewBlock = true;853            lastConstructStmtEvaluation = &eval;854          },855          [&](const parser::ReturnStmt &) {856            eval.isUnstructured = true;857            if (eval.lexicalSuccessor->lexicalSuccessor)858              markSuccessorAsNewBlock(eval);859          },860          [&](const parser::StopStmt &) {861            eval.isUnstructured = true;862            if (eval.lexicalSuccessor->lexicalSuccessor)863              markSuccessorAsNewBlock(eval);864          },865          [&](const parser::ComputedGotoStmt &s) {866            for (auto &label : std::get<std::list<parser::Label>>(s.t))867              markBranchTarget(eval, label);868          },869          [&](const parser::ArithmeticIfStmt &s) {870            markBranchTarget(eval, std::get<1>(s.t));871            markBranchTarget(eval, std::get<2>(s.t));872            markBranchTarget(eval, std::get<3>(s.t));873          },874          [&](const parser::AssignStmt &s) { // legacy label assignment875            auto &label = std::get<parser::Label>(s.t);876            const auto *sym = std::get<parser::Name>(s.t).symbol;877            assert(sym && "missing AssignStmt symbol");878            lower::pft::Evaluation *target{879                labelEvaluationMap->find(label)->second};880            assert(target && "missing branch target evaluation");881            if (!target->isA<parser::FormatStmt>()) {882              target->isNewBlock = true;883              for (lower::pft::Evaluation *parent = target->parentConstruct;884                   parent; parent = parent->parentConstruct) {885                parent->isUnstructured = true;886                // The exit of an enclosing DO or IF construct is a new block.887                if (parent->constructExit &&888                    (parent->isA<parser::DoConstruct>() ||889                     parent->isA<parser::IfConstruct>()))890                  parent->constructExit->isNewBlock = true;891              }892            }893            auto iter = assignSymbolLabelMap->find(*sym);894            if (iter == assignSymbolLabelMap->end()) {895              lower::pft::LabelSet labelSet{};896              labelSet.insert(label);897              assignSymbolLabelMap->try_emplace(*sym, labelSet);898            } else {899              iter->second.insert(label);900            }901          },902          [&](const parser::AssignedGotoStmt &) {903            // Although this statement is a branch, it doesn't have any904            // explicit control successors. So the code at the end of the905            // loop won't mark the successor. Do that here.906            eval.isUnstructured = true;907            markSuccessorAsNewBlock(eval);908          },909 910          // The first executable statement after an EntryStmt is a new block.911          [&](const parser::EntryStmt &) {912            eval.lexicalSuccessor->isNewBlock = true;913          },914 915          // Construct statements916          [&](const parser::AssociateStmt &s) {917            insertConstructName(s, parentConstruct);918          },919          [&](const parser::BlockStmt &s) {920            insertConstructName(s, parentConstruct);921          },922          [&](const parser::SelectCaseStmt &s) {923            insertConstructName(s, parentConstruct);924            lastConstructStmtEvaluation = &eval;925          },926          [&](const parser::CaseStmt &) {927            eval.isNewBlock = true;928            lastConstructStmtEvaluation->controlSuccessor = &eval;929            lastConstructStmtEvaluation = &eval;930          },931          [&](const parser::EndSelectStmt &) {932            eval.isNewBlock = true;933            lastConstructStmtEvaluation = nullptr;934          },935          [&](const parser::ChangeTeamStmt &s) {936            insertConstructName(s, parentConstruct);937          },938          [&](const parser::CriticalStmt &s) {939            insertConstructName(s, parentConstruct);940          },941          [&](const parser::NonLabelDoStmt &s) {942            insertConstructName(s, parentConstruct);943            doConstructStack.push_back(parentConstruct);944            const auto &loopControl =945                std::get<std::optional<parser::LoopControl>>(s.t);946            if (!loopControl.has_value()) {947              eval.isUnstructured = true; // infinite loop948              return;949            }950            eval.nonNopSuccessor().isNewBlock = true;951            eval.controlSuccessor = &evaluationList.back();952            if (const auto *bounds =953                    std::get_if<parser::LoopControl::Bounds>(&loopControl->u)) {954              if (bounds->name.thing.symbol->GetType()->IsNumeric(955                      common::TypeCategory::Real))956                eval.isUnstructured = true; // real-valued loop control957            } else if (std::get_if<parser::ScalarLogicalExpr>(958                           &loopControl->u)) {959              eval.isUnstructured = true; // while loop960            }961          },962          [&](const parser::EndDoStmt &) {963            lower::pft::Evaluation &doEval = evaluationList.front();964            eval.controlSuccessor = &doEval;965            doConstructStack.pop_back();966            if (parentConstruct->lowerAsStructured())967              return;968            // The loop is unstructured, which wasn't known for all cases when969            // visiting the NonLabelDoStmt.970            parentConstruct->constructExit->isNewBlock = true;971            const auto &doStmt = *doEval.getIf<parser::NonLabelDoStmt>();972            const auto &loopControl =973                std::get<std::optional<parser::LoopControl>>(doStmt.t);974            if (!loopControl.has_value())975              return; // infinite loop976            if (const auto *concurrent =977                    std::get_if<parser::LoopControl::Concurrent>(978                        &loopControl->u)) {979              // If there is a mask, the EndDoStmt starts a new block.980              const auto &header =981                  std::get<parser::ConcurrentHeader>(concurrent->t);982              eval.isNewBlock |=983                  std::get<std::optional<parser::ScalarLogicalExpr>>(header.t)984                      .has_value();985            }986          },987          [&](const parser::IfThenStmt &s) {988            insertConstructName(s, parentConstruct);989            eval.lexicalSuccessor->isNewBlock = true;990            lastConstructStmtEvaluation = &eval;991          },992          [&](const parser::ElseIfStmt &) {993            eval.isNewBlock = true;994            eval.lexicalSuccessor->isNewBlock = true;995            lastConstructStmtEvaluation->controlSuccessor = &eval;996            lastConstructStmtEvaluation = &eval;997          },998          [&](const parser::ElseStmt &) {999            eval.isNewBlock = true;1000            lastConstructStmtEvaluation->controlSuccessor = &eval;1001            lastConstructStmtEvaluation = nullptr;1002          },1003          [&](const parser::EndIfStmt &) {1004            if (parentConstruct->lowerAsUnstructured())1005              parentConstruct->constructExit->isNewBlock = true;1006            if (lastConstructStmtEvaluation) {1007              lastConstructStmtEvaluation->controlSuccessor =1008                  parentConstruct->constructExit;1009              lastConstructStmtEvaluation = nullptr;1010            }1011          },1012          [&](const parser::SelectRankStmt &s) {1013            insertConstructName(s, parentConstruct);1014            lastConstructStmtEvaluation = &eval;1015          },1016          [&](const parser::SelectRankCaseStmt &) {1017            eval.isNewBlock = true;1018            lastConstructStmtEvaluation->controlSuccessor = &eval;1019            lastConstructStmtEvaluation = &eval;1020          },1021          [&](const parser::SelectTypeStmt &s) {1022            insertConstructName(s, parentConstruct);1023            lastConstructStmtEvaluation = &eval;1024          },1025          [&](const parser::TypeGuardStmt &) {1026            eval.isNewBlock = true;1027            lastConstructStmtEvaluation->controlSuccessor = &eval;1028            lastConstructStmtEvaluation = &eval;1029          },1030 1031          // Constructs - set (unstructured) construct exit targets1032          [&](const parser::AssociateConstruct &) {1033            eval.constructExit = &eval.evaluationList->back();1034          },1035          [&](const parser::BlockConstruct &) {1036            eval.constructExit = &eval.evaluationList->back();1037          },1038          [&](const parser::CaseConstruct &) {1039            eval.constructExit = &eval.evaluationList->back();1040            eval.isUnstructured = true;1041          },1042          [&](const parser::ChangeTeamConstruct &) {1043            eval.constructExit = &eval.evaluationList->back();1044          },1045          [&](const parser::CriticalConstruct &) {1046            eval.constructExit = &eval.evaluationList->back();1047          },1048          [&](const parser::DoConstruct &) { setConstructExit(eval); },1049          [&](const parser::ForallConstruct &) { setConstructExit(eval); },1050          [&](const parser::IfConstruct &) { setConstructExit(eval); },1051          [&](const parser::SelectRankConstruct &) {1052            eval.constructExit = &eval.evaluationList->back();1053            eval.isUnstructured = true;1054          },1055          [&](const parser::SelectTypeConstruct &) {1056            eval.constructExit = &eval.evaluationList->back();1057            eval.isUnstructured = true;1058          },1059          [&](const parser::WhereConstruct &) { setConstructExit(eval); },1060 1061          // Default - Common analysis for IO statements; otherwise nop.1062          [&](const auto &stmt) {1063            using A = std::decay_t<decltype(stmt)>;1064            using IoStmts = std::tuple<1065                parser::BackspaceStmt, parser::CloseStmt, parser::EndfileStmt,1066                parser::FlushStmt, parser::InquireStmt, parser::OpenStmt,1067                parser::PrintStmt, parser::ReadStmt, parser::RewindStmt,1068                parser::WaitStmt, parser::WriteStmt>;1069            if constexpr (common::HasMember<A, IoStmts>)1070              analyzeIoBranches(eval, stmt);1071          },1072      });1073 1074      // Analyze construct evaluations.1075      if (eval.evaluationList)1076        analyzeBranches(&eval, *eval.evaluationList);1077 1078      // Propagate isUnstructured flag to enclosing construct.1079      if (parentConstruct && eval.isUnstructured)1080        parentConstruct->isUnstructured = true;1081 1082      // The successor of a branch starts a new block.1083      if (eval.controlSuccessor && eval.isActionStmt() &&1084          eval.lowerAsUnstructured())1085        markSuccessorAsNewBlock(eval);1086    }1087  }1088 1089  /// Do processing specific to subprograms with multiple entry points.1090  void processEntryPoints() {1091    lower::pft::Evaluation *initialEval = &evaluationListStack.back()->front();1092    lower::pft::FunctionLikeUnit *unit = initialEval->getOwningProcedure();1093    int entryCount = unit->entryPointList.size();1094    if (entryCount == 1)1095      return;1096 1097    // The first executable statement in the subprogram is preceded by a1098    // branch to the entry point, so it starts a new block.1099    // OpenMP directives can generate code around the nested evaluations.1100    if (initialEval->hasNestedEvaluations() &&1101        !initialEval->isOpenMPDirective())1102      initialEval = &initialEval->getFirstNestedEvaluation();1103    else if (initialEval->isA<Fortran::parser::EntryStmt>())1104      initialEval = initialEval->lexicalSuccessor;1105    initialEval->isNewBlock = true;1106 1107    // All function entry points share a single result container.1108    // Find one of the largest results.1109    for (int entryIndex = 0; entryIndex < entryCount; ++entryIndex) {1110      unit->setActiveEntry(entryIndex);1111      const auto &details =1112          unit->getSubprogramSymbol().get<semantics::SubprogramDetails>();1113      if (details.isFunction()) {1114        const semantics::Symbol *resultSym = &details.result();1115        assert(resultSym && "missing result symbol");1116        if (!unit->primaryResult ||1117            unit->primaryResult->size() < resultSym->size())1118          unit->primaryResult = resultSym;1119      }1120    }1121    unit->setActiveEntry(0);1122  }1123 1124  std::unique_ptr<lower::pft::Program> pgm;1125  std::vector<lower::pft::PftNode> pftParentStack;1126  const semantics::SemanticsContext &semanticsContext;1127 1128  llvm::SmallVector<bool> containsStmtStack{};1129  lower::pft::ContainedUnitList *containedUnitList{};1130  std::vector<lower::pft::Evaluation *> constructAndDirectiveStack{};1131  std::vector<lower::pft::Evaluation *> doConstructStack{};1132  /// evaluationListStack is the current nested construct evaluationList state.1133  std::vector<lower::pft::EvaluationList *> evaluationListStack{};1134  llvm::DenseMap<parser::Label, lower::pft::Evaluation *> *labelEvaluationMap{};1135  lower::pft::SymbolLabelMap *assignSymbolLabelMap{};1136  std::map<std::string, lower::pft::Evaluation *> constructNameMap{};1137  int specificationPartLevel{};1138  lower::pft::Evaluation *lastLexicalEvaluation{};1139};1140 1141#ifndef NDEBUG1142/// Dump all program scopes and symbols with addresses to disambiguate names.1143/// This is static, unchanging front end information, so dump it only once.1144void dumpScope(const semantics::Scope *scope, int depth) {1145  static int initialVisitCounter = 0;1146  if (depth < 0) {1147    if (++initialVisitCounter != 1)1148      return;1149    while (!scope->IsGlobal())1150      scope = &scope->parent();1151    LLVM_DEBUG(llvm::dbgs() << "Full program scope information.\n"1152                               "Addresses in angle brackets are scopes. "1153                               "Unbracketed addresses are symbols.\n");1154  }1155  static const std::string white{"                                      ++"};1156  std::string w = white.substr(0, depth * 2);1157  if (depth >= 0) {1158    LLVM_DEBUG(llvm::dbgs() << w << "<" << scope << "> ");1159    if (auto *sym{scope->symbol()}) {1160      LLVM_DEBUG(llvm::dbgs() << sym << " " << *sym << "\n");1161    } else {1162      if (scope->IsIntrinsicModules()) {1163        LLVM_DEBUG(llvm::dbgs() << "IntrinsicModules (no detail)\n");1164        return;1165      }1166      if (scope->kind() == Fortran::semantics::Scope::Kind::BlockConstruct)1167        LLVM_DEBUG(llvm::dbgs() << "[block]\n");1168      else1169        LLVM_DEBUG(llvm::dbgs() << "[anonymous]\n");1170    }1171  }1172  for (const auto &scp : scope->children())1173    if (!scp.symbol())1174      dumpScope(&scp, depth + 1);1175  for (auto iter = scope->begin(); iter != scope->end(); ++iter) {1176    common::Reference<semantics::Symbol> sym = iter->second;1177    if (auto scp = sym->scope())1178      dumpScope(scp, depth + 1);1179    else1180      LLVM_DEBUG(llvm::dbgs() << w + "  " << &*sym << "   " << *sym << "\n");1181  }1182}1183#endif // NDEBUG1184 1185class PFTDumper {1186public:1187  void dumpPFT(llvm::raw_ostream &outputStream,1188               const lower::pft::Program &pft) {1189    for (auto &unit : pft.getUnits()) {1190      Fortran::common::visit(1191          common::visitors{1192              [&](const lower::pft::BlockDataUnit &unit) {1193                outputStream << getNodeIndex(unit) << " ";1194                outputStream << "BlockData: ";1195                outputStream << "\nEnd BlockData\n\n";1196              },1197              [&](const lower::pft::FunctionLikeUnit &func) {1198                dumpFunctionLikeUnit(outputStream, func);1199              },1200              [&](const lower::pft::ModuleLikeUnit &unit) {1201                dumpModuleLikeUnit(outputStream, unit);1202              },1203              [&](const lower::pft::CompilerDirectiveUnit &unit) {1204                dumpCompilerDirectiveUnit(outputStream, unit);1205              },1206              [&](const lower::pft::OpenACCDirectiveUnit &unit) {1207                dumpOpenACCDirectiveUnit(outputStream, unit);1208              },1209          },1210          unit);1211    }1212  }1213 1214  llvm::StringRef evaluationName(const lower::pft::Evaluation &eval) {1215    return eval.visit([](const auto &parseTreeNode) {1216      return parser::ParseTreeDumper::GetNodeName(parseTreeNode);1217    });1218  }1219 1220  void dumpEvaluation(llvm::raw_ostream &outputStream,1221                      const lower::pft::Evaluation &eval,1222                      const std::string &indentString, int indent = 1) {1223    llvm::StringRef name = evaluationName(eval);1224    llvm::StringRef newBlock = eval.isNewBlock ? "^" : "";1225    llvm::StringRef bang = eval.isUnstructured ? "!" : "";1226    outputStream << indentString;1227    if (eval.printIndex)1228      outputStream << eval.printIndex << ' ';1229    if (eval.hasNestedEvaluations())1230      outputStream << "<<" << newBlock << name << bang << ">>";1231    else1232      outputStream << newBlock << name << bang;1233    if (eval.negateCondition)1234      outputStream << " [negate]";1235    if (eval.constructExit)1236      outputStream << " -> " << eval.constructExit->printIndex;1237    else if (eval.controlSuccessor)1238      outputStream << " -> " << eval.controlSuccessor->printIndex;1239    else if (eval.isA<parser::EntryStmt>() && eval.lexicalSuccessor)1240      outputStream << " -> " << eval.lexicalSuccessor->printIndex;1241    bool extraNewline = false;1242    if (!eval.position.empty())1243      outputStream << ": " << eval.position.ToString();1244    else if (auto *dir = eval.getIf<parser::CompilerDirective>()) {1245      extraNewline = dir->source.ToString().back() == '\n';1246      outputStream << ": !" << dir->source.ToString();1247    }1248    if (!extraNewline)1249      outputStream << '\n';1250    if (eval.hasNestedEvaluations()) {1251      dumpEvaluationList(outputStream, *eval.evaluationList, indent + 1);1252      outputStream << indentString << "<<End " << name << bang << ">>\n";1253    }1254  }1255 1256  void dumpEvaluation(llvm::raw_ostream &ostream,1257                      const lower::pft::Evaluation &eval) {1258    dumpEvaluation(ostream, eval, "");1259  }1260 1261  void dumpEvaluationList(llvm::raw_ostream &outputStream,1262                          const lower::pft::EvaluationList &evaluationList,1263                          int indent = 1) {1264    static const auto white = "                                      ++"s;1265    auto indentString = white.substr(0, indent * 2);1266    for (const lower::pft::Evaluation &eval : evaluationList)1267      dumpEvaluation(outputStream, eval, indentString, indent);1268  }1269 1270  void1271  dumpFunctionLikeUnit(llvm::raw_ostream &outputStream,1272                       const lower::pft::FunctionLikeUnit &functionLikeUnit) {1273    outputStream << getNodeIndex(functionLikeUnit) << " ";1274    llvm::StringRef unitKind;1275    llvm::StringRef name;1276    llvm::StringRef header;1277    if (functionLikeUnit.beginStmt) {1278      functionLikeUnit.beginStmt->visit(common::visitors{1279          [&](const parser::Statement<parser::ProgramStmt> &stmt) {1280            unitKind = "Program";1281            name = toStringRef(stmt.statement.v.source);1282          },1283          [&](const parser::Statement<parser::FunctionStmt> &stmt) {1284            unitKind = "Function";1285            name = toStringRef(std::get<parser::Name>(stmt.statement.t).source);1286            header = toStringRef(stmt.source);1287          },1288          [&](const parser::Statement<parser::SubroutineStmt> &stmt) {1289            unitKind = "Subroutine";1290            name = toStringRef(std::get<parser::Name>(stmt.statement.t).source);1291            header = toStringRef(stmt.source);1292          },1293          [&](const parser::Statement<parser::MpSubprogramStmt> &stmt) {1294            unitKind = "MpSubprogram";1295            name = toStringRef(stmt.statement.v.source);1296            header = toStringRef(stmt.source);1297          },1298          [&](const auto &) { llvm_unreachable("not a valid begin stmt"); },1299      });1300    } else {1301      unitKind = "Program";1302      name = "<anonymous>";1303    }1304    outputStream << unitKind << ' ' << name;1305    if (!header.empty())1306      outputStream << ": " << header;1307    outputStream << '\n';1308    dumpEvaluationList(outputStream, functionLikeUnit.evaluationList);1309    dumpContainedUnitList(outputStream, functionLikeUnit.containedUnitList);1310    outputStream << "End " << unitKind << ' ' << name << "\n\n";1311  }1312 1313  void dumpModuleLikeUnit(llvm::raw_ostream &outputStream,1314                          const lower::pft::ModuleLikeUnit &moduleLikeUnit) {1315    outputStream << getNodeIndex(moduleLikeUnit) << " ";1316    llvm::StringRef unitKind;1317    llvm::StringRef name;1318    llvm::StringRef header;1319    moduleLikeUnit.beginStmt.visit(common::visitors{1320        [&](const parser::Statement<parser::ModuleStmt> &stmt) {1321          unitKind = "Module";1322          name = toStringRef(stmt.statement.v.source);1323          header = toStringRef(stmt.source);1324        },1325        [&](const parser::Statement<parser::SubmoduleStmt> &stmt) {1326          unitKind = "Submodule";1327          name = toStringRef(std::get<parser::Name>(stmt.statement.t).source);1328          header = toStringRef(stmt.source);1329        },1330        [&](const auto &) {1331          llvm_unreachable("not a valid module begin stmt");1332        },1333    });1334    outputStream << unitKind << ' ' << name << ": " << header << '\n';1335    dumpEvaluationList(outputStream, moduleLikeUnit.evaluationList);1336    dumpContainedUnitList(outputStream, moduleLikeUnit.containedUnitList);1337    outputStream << "End " << unitKind << ' ' << name << "\n\n";1338  }1339 1340  // Top level directives1341  void dumpCompilerDirectiveUnit(1342      llvm::raw_ostream &outputStream,1343      const lower::pft::CompilerDirectiveUnit &directive) {1344    outputStream << getNodeIndex(directive) << " ";1345    outputStream << "CompilerDirective: !";1346    bool extraNewline =1347        directive.get<parser::CompilerDirective>().source.ToString().back() ==1348        '\n';1349    outputStream1350        << directive.get<parser::CompilerDirective>().source.ToString();1351    if (!extraNewline)1352      outputStream << "\n";1353    outputStream << "\n";1354  }1355 1356  void dumpContainedUnitList(1357      llvm::raw_ostream &outputStream,1358      const lower::pft::ContainedUnitList &containedUnitList) {1359    if (containedUnitList.empty())1360      return;1361    outputStream << "\nContains\n";1362    for (const lower::pft::ContainedUnit &unit : containedUnitList)1363      if (const auto *func = std::get_if<lower::pft::FunctionLikeUnit>(&unit)) {1364        dumpFunctionLikeUnit(outputStream, *func);1365      } else if (const auto *dir =1366                     std::get_if<lower::pft::CompilerDirectiveUnit>(&unit)) {1367        outputStream << getNodeIndex(*dir) << " ";1368        dumpEvaluation(outputStream,1369                       lower::pft::Evaluation{1370                           dir->get<parser::CompilerDirective>(), dir->parent});1371        outputStream << "\n";1372      }1373    outputStream << "End Contains\n";1374  }1375 1376  void1377  dumpOpenACCDirectiveUnit(llvm::raw_ostream &outputStream,1378                           const lower::pft::OpenACCDirectiveUnit &directive) {1379    outputStream << getNodeIndex(directive) << " ";1380    outputStream << "OpenACCDirective: !$acc ";1381    outputStream1382        << directive.get<parser::OpenACCRoutineConstruct>().source.ToString();1383    outputStream << "\nEnd OpenACCDirective\n\n";1384  }1385 1386  template <typename T>1387  std::size_t getNodeIndex(const T &node) {1388    auto addr = static_cast<const void *>(&node);1389    auto it = nodeIndexes.find(addr);1390    if (it != nodeIndexes.end())1391      return it->second;1392    nodeIndexes.try_emplace(addr, nextIndex);1393    return nextIndex++;1394  }1395  std::size_t getNodeIndex(const lower::pft::Program &) { return 0; }1396 1397private:1398  llvm::DenseMap<const void *, std::size_t> nodeIndexes;1399  std::size_t nextIndex{1}; // 0 is the root1400};1401 1402} // namespace1403 1404template <typename A, typename T>1405static lower::pft::FunctionLikeUnit::FunctionStatement1406getFunctionStmt(const T &func) {1407  lower::pft::FunctionLikeUnit::FunctionStatement result{1408      std::get<parser::Statement<A>>(func.t)};1409  return result;1410}1411 1412template <typename A, typename T>1413static lower::pft::ModuleLikeUnit::ModuleStatement getModuleStmt(const T &mod) {1414  lower::pft::ModuleLikeUnit::ModuleStatement result{1415      std::get<parser::Statement<A>>(mod.t)};1416  return result;1417}1418 1419template <typename A>1420static const semantics::Symbol *getSymbol(A &beginStmt) {1421  const auto *symbol = beginStmt.visit(common::visitors{1422      [](const parser::Statement<parser::ProgramStmt> &stmt)1423          -> const semantics::Symbol * { return stmt.statement.v.symbol; },1424      [](const parser::Statement<parser::FunctionStmt> &stmt)1425          -> const semantics::Symbol * {1426        return std::get<parser::Name>(stmt.statement.t).symbol;1427      },1428      [](const parser::Statement<parser::SubroutineStmt> &stmt)1429          -> const semantics::Symbol * {1430        return std::get<parser::Name>(stmt.statement.t).symbol;1431      },1432      [](const parser::Statement<parser::MpSubprogramStmt> &stmt)1433          -> const semantics::Symbol * { return stmt.statement.v.symbol; },1434      [](const parser::Statement<parser::ModuleStmt> &stmt)1435          -> const semantics::Symbol * { return stmt.statement.v.symbol; },1436      [](const parser::Statement<parser::SubmoduleStmt> &stmt)1437          -> const semantics::Symbol * {1438        return std::get<parser::Name>(stmt.statement.t).symbol;1439      },1440      [](const auto &) -> const semantics::Symbol * {1441        llvm_unreachable("unknown FunctionLike or ModuleLike beginStmt");1442        return nullptr;1443      }});1444  assert(symbol && "parser::Name must have resolved symbol");1445  return symbol;1446}1447 1448bool Fortran::lower::pft::Evaluation::lowerAsStructured() const {1449  return !lowerAsUnstructured();1450}1451 1452bool Fortran::lower::pft::Evaluation::lowerAsUnstructured() const {1453  return isUnstructured || clDisableStructuredFir;1454}1455 1456bool Fortran::lower::pft::Evaluation::forceAsUnstructured() const {1457  return clDisableStructuredFir;1458}1459 1460lower::pft::FunctionLikeUnit *1461Fortran::lower::pft::Evaluation::getOwningProcedure() const {1462  return parent.visit(common::visitors{1463      [](lower::pft::FunctionLikeUnit &c) { return &c; },1464      [&](lower::pft::Evaluation &c) { return c.getOwningProcedure(); },1465      [](auto &) -> lower::pft::FunctionLikeUnit * { return nullptr; },1466  });1467}1468 1469bool Fortran::lower::definedInCommonBlock(const semantics::Symbol &sym) {1470  return semantics::FindCommonBlockContaining(sym);1471}1472 1473/// Is the symbol `sym` a global?1474bool Fortran::lower::symbolIsGlobal(const semantics::Symbol &sym) {1475  return (semantics::IsSaved(sym) && semantics::CanCUDASymbolBeGlobal(sym)) ||1476         lower::definedInCommonBlock(sym) || semantics::IsNamedConstant(sym);1477}1478 1479namespace {1480/// This helper class sorts the symbols in a scope such that a symbol will1481/// be placed after those it depends upon. Otherwise the sort is stable and1482/// preserves the order of the symbol table, which is sorted by name. This1483/// analysis may also be done for an individual symbol.1484struct SymbolDependenceAnalysis {1485  explicit SymbolDependenceAnalysis(const semantics::Scope &scope) {1486    analyzeEquivalenceSets(scope);1487    for (const auto &iter : scope)1488      analyze(iter.second.get());1489    finalize();1490  }1491  explicit SymbolDependenceAnalysis(const semantics::Symbol &symbol) {1492    analyzeEquivalenceSets(symbol.owner());1493    analyze(symbol);1494    finalize();1495  }1496  Fortran::lower::pft::VariableList getVariableList() {1497    return std::move(layeredVarList[0]);1498  }1499 1500private:1501  /// Analyze the equivalence sets defined in \p scope, plus the equivalence1502  /// sets in host module, submodule, and procedure scopes that may define1503  /// symbols referenced in \p scope. This analysis excludes equivalence sets1504  /// involving common blocks, which are handled elsewhere.1505  void analyzeEquivalenceSets(const semantics::Scope &scope) {1506    // FIXME: When this function is called on the scope of an internal1507    // procedure whose parent contains an EQUIVALENCE set and the internal1508    // procedure uses variables from that EQUIVALENCE set, we end up creating1509    // an AggregateStore for those variables unnecessarily.1510 1511    // A function defined in a [sub]module has no explicit USE of its ancestor1512    // [sub]modules. Analyze those scopes here to accommodate references to1513    // symbols in them.1514    for (auto *scp = &scope.parent(); !scp->IsGlobal(); scp = &scp->parent())1515      if (scp->kind() == Fortran::semantics::Scope::Kind::Module)1516        analyzeLocalEquivalenceSets(*scp);1517    // Analyze local, USEd, and host procedure scope equivalences.1518    for (const auto &iter : scope) {1519      const semantics::Symbol &ultimate = iter.second.get().GetUltimate();1520      if (!skipSymbol(ultimate))1521        analyzeLocalEquivalenceSets(ultimate.owner());1522    }1523    // Add all aggregate stores to the front of the variable list.1524    adjustSize(1);1525    // The copy in the loop matters, 'stores' will still be used.1526    for (auto st : stores)1527      layeredVarList[0].emplace_back(std::move(st));1528  }1529 1530  /// Analyze the equivalence sets defined locally in \p scope that don't1531  /// involve common blocks.1532  void analyzeLocalEquivalenceSets(const semantics::Scope &scope) {1533    if (scope.equivalenceSets().empty())1534      return; // no equivalence sets to analyze1535    if (analyzedScopes.contains(&scope))1536      return; // equivalence sets already analyzed1537 1538    analyzedScopes.insert(&scope);1539    std::list<std::list<semantics::SymbolRef>> aggregates =1540        Fortran::semantics::GetStorageAssociations(scope);1541    for (std::list<semantics::SymbolRef> aggregate : aggregates) {1542      const Fortran::semantics::Symbol *aggregateSym = nullptr;1543      bool isGlobal = false;1544      const semantics::Symbol &first = *aggregate.front();1545      // Exclude equivalence sets involving common blocks.1546      // Those are handled in instantiateCommon.1547      if (lower::definedInCommonBlock(first))1548        continue;1549      std::size_t start = first.offset();1550      std::size_t end = first.offset() + first.size();1551      const Fortran::semantics::Symbol *namingSym = nullptr;1552      for (semantics::SymbolRef symRef : aggregate) {1553        const semantics::Symbol &sym = *symRef;1554        aliasSyms.insert(&sym);1555        if (sym.test(Fortran::semantics::Symbol::Flag::CompilerCreated)) {1556          aggregateSym = &sym;1557        } else {1558          isGlobal |= lower::symbolIsGlobal(sym);1559          start = std::min(sym.offset(), start);1560          end = std::max(sym.offset() + sym.size(), end);1561          if (!namingSym || (sym.name() < namingSym->name()))1562            namingSym = &sym;1563        }1564      }1565      assert(namingSym && "must contain at least one user symbol");1566      if (!aggregateSym) {1567        stores.emplace_back(1568            Fortran::lower::pft::Variable::Interval{start, end - start},1569            *namingSym, isGlobal);1570      } else {1571        stores.emplace_back(*aggregateSym, *namingSym, isGlobal);1572      }1573    }1574  }1575 1576  // Recursively visit each symbol to determine the height of its dependence on1577  // other symbols.1578  int analyze(const semantics::Symbol &sym) {1579    auto done = seen.insert(&sym);1580    if (!done.second)1581      return 0;1582    LLVM_DEBUG(llvm::dbgs() << "analyze symbol " << &sym << " in <"1583                            << &sym.owner() << ">: " << sym << '\n');1584    const semantics::Symbol &ultimate = sym.GetUltimate();1585    if (const auto *details = ultimate.detailsIf<semantics::GenericDetails>()) {1586      // Procedure pointers may be "hidden" behind to the generic symbol if they1587      // have the same name.1588      if (const semantics::Symbol *specific = details->specific())1589        analyze(*specific);1590      return 0;1591    }1592    const bool isProcedurePointerOrDummy =1593        semantics::IsProcedurePointer(sym) ||1594        (semantics::IsProcedure(sym) && IsDummy(sym));1595    // A procedure argument in a subprogram with multiple entry points might1596    // need a layeredVarList entry to trigger creation of a symbol map entry1597    // in some cases. Non-dummy procedures don't.1598    if (semantics::IsProcedure(sym) && !isProcedurePointerOrDummy)1599      return 0;1600    // Derived type component symbols may be collected by "CollectSymbols"1601    // below when processing something like "real :: x(derived%component)". The1602    // symbol "component" has "ObjectEntityDetails", but it should not be1603    // instantiated: it is part of "derived" that should be the only one to1604    // be instantiated.1605    if (sym.owner().IsDerivedType())1606      return 0;1607 1608    if (const auto *details =1609            ultimate.detailsIf<semantics::NamelistDetails>()) {1610      // handle namelist group symbols1611      for (const semantics::SymbolRef &s : details->objects())1612        analyze(s);1613      return 0;1614    }1615    if (!ultimate.has<semantics::ObjectEntityDetails>() &&1616        !isProcedurePointerOrDummy)1617      return 0;1618 1619    if (sym.has<semantics::DerivedTypeDetails>())1620      llvm_unreachable("not yet implemented - derived type analysis");1621 1622    // Symbol must be something lowering will have to allocate.1623    int depth = 0;1624    // Analyze symbols appearing in object entity specification expressions.1625    // This ensures these symbols will be instantiated before the current one.1626    // This is not done for object entities that are host associated because1627    // they must be instantiated from the value of the host symbols.1628    // (The specification expressions should not be re-evaluated.)1629    if (const auto *details = sym.detailsIf<semantics::ObjectEntityDetails>()) {1630      const semantics::DeclTypeSpec *symTy = sym.GetType();1631      assert(symTy && "symbol must have a type");1632      // check CHARACTER's length1633      if (symTy->category() == semantics::DeclTypeSpec::Character)1634        if (auto e = symTy->characterTypeSpec().length().GetExplicit())1635          for (const auto &s : evaluate::CollectSymbols(*e))1636            depth = std::max(analyze(s) + 1, depth);1637 1638      auto doExplicit = [&](const auto &bound) {1639        if (bound.isExplicit()) {1640          semantics::SomeExpr e{*bound.GetExplicit()};1641          for (const auto &s : evaluate::CollectSymbols(e))1642            depth = std::max(analyze(s) + 1, depth);1643        }1644      };1645      // Handle any symbols in array bound declarations.1646      for (const semantics::ShapeSpec &subs : details->shape()) {1647        doExplicit(subs.lbound());1648        doExplicit(subs.ubound());1649      }1650      // Handle any symbols in coarray bound declarations.1651      for (const semantics::ShapeSpec &subs : details->coshape()) {1652        doExplicit(subs.lbound());1653        doExplicit(subs.ubound());1654      }1655      // Handle any symbols in initialization expressions.1656      if (auto e = details->init())1657        for (const auto &s : evaluate::CollectSymbols(*e))1658          if (!s->has<semantics::DerivedTypeDetails>())1659            depth = std::max(analyze(s) + 1, depth);1660    }1661 1662    // Make sure cray pointer is instantiated even if it is not visible.1663    if (ultimate.test(Fortran::semantics::Symbol::Flag::CrayPointee))1664      depth = std::max(1665          analyze(Fortran::semantics::GetCrayPointer(ultimate)) + 1, depth);1666    adjustSize(depth + 1);1667    bool global = lower::symbolIsGlobal(sym);1668    layeredVarList[depth].emplace_back(sym, global, depth);1669    if (semantics::IsAllocatable(sym))1670      layeredVarList[depth].back().setHeapAlloc();1671    if (semantics::IsPointer(sym))1672      layeredVarList[depth].back().setPointer();1673    if (ultimate.attrs().test(semantics::Attr::TARGET))1674      layeredVarList[depth].back().setTarget();1675 1676    // If there are alias sets, then link the participating variables to their1677    // aggregate stores when constructing the new variable on the list.1678    if (lower::pft::Variable::AggregateStore *store = findStoreIfAlias(sym))1679      layeredVarList[depth].back().setAlias(store->getOffset());1680    return depth;1681  }1682 1683  /// Skip symbol in alias analysis.1684  bool skipSymbol(const semantics::Symbol &sym) {1685    // Common block equivalences are largely managed by the front end.1686    // Compiler generated symbols ('.' names) cannot be equivalenced.1687    // FIXME: Equivalence code generation may need to be revisited.1688    return !sym.has<semantics::ObjectEntityDetails>() ||1689           lower::definedInCommonBlock(sym) || sym.name()[0] == '.';1690  }1691 1692  // Make sure the table is of appropriate size.1693  void adjustSize(std::size_t size) {1694    if (layeredVarList.size() < size)1695      layeredVarList.resize(size);1696  }1697 1698  Fortran::lower::pft::Variable::AggregateStore *1699  findStoreIfAlias(const Fortran::evaluate::Symbol &sym) {1700    const semantics::Symbol &ultimate = sym.GetUltimate();1701    const semantics::Scope &scope = ultimate.owner();1702    // Expect the total number of EQUIVALENCE sets to be small for a typical1703    // Fortran program.1704    if (aliasSyms.contains(&ultimate)) {1705      LLVM_DEBUG(llvm::dbgs() << "found aggregate containing " << &ultimate1706                              << " " << ultimate.name() << " in <" << &scope1707                              << "> " << scope.GetName() << '\n');1708      std::size_t off = ultimate.offset();1709      std::size_t symSize = ultimate.size();1710      for (lower::pft::Variable::AggregateStore &v : stores) {1711        if (&v.getOwningScope() == &scope) {1712          auto intervalOff = std::get<0>(v.interval);1713          auto intervalSize = std::get<1>(v.interval);1714          if (off >= intervalOff && off < intervalOff + intervalSize)1715            return &v;1716          // Zero sized symbol in zero sized equivalence.1717          if (off == intervalOff && symSize == 0)1718            return &v;1719        }1720      }1721      // clang-format off1722      LLVM_DEBUG(1723          llvm::dbgs() << "looking for " << off << "\n{\n";1724          for (lower::pft::Variable::AggregateStore &v : stores) {1725            llvm::dbgs() << " in scope: " << &v.getOwningScope() << "\n";1726            llvm::dbgs() << "  i = [" << std::get<0>(v.interval) << ".."1727                << std::get<0>(v.interval) + std::get<1>(v.interval)1728                << "]\n";1729          }1730          llvm::dbgs() << "}\n");1731      // clang-format on1732      llvm_unreachable("the store must be present");1733    }1734    return nullptr;1735  }1736 1737  /// Flatten the result VariableList.1738  void finalize() {1739    for (int i = 1, end = layeredVarList.size(); i < end; ++i)1740      layeredVarList[0].insert(layeredVarList[0].end(),1741                               layeredVarList[i].begin(),1742                               layeredVarList[i].end());1743  }1744 1745  llvm::SmallPtrSet<const semantics::Symbol *, 32> seen;1746  std::vector<Fortran::lower::pft::VariableList> layeredVarList;1747  llvm::SmallPtrSet<const semantics::Symbol *, 32> aliasSyms;1748  /// Set of scopes that have been analyzed for aliases.1749  llvm::SmallPtrSet<const semantics::Scope *, 4> analyzedScopes;1750  std::vector<Fortran::lower::pft::Variable::AggregateStore> stores;1751};1752} // namespace1753 1754//===----------------------------------------------------------------------===//1755// FunctionLikeUnit implementation1756//===----------------------------------------------------------------------===//1757 1758Fortran::lower::pft::FunctionLikeUnit::FunctionLikeUnit(1759    const parser::MainProgram &func, const lower::pft::PftNode &parent,1760    const semantics::SemanticsContext &semanticsContext)1761    : ProgramUnit{func, parent},1762      endStmt{getFunctionStmt<parser::EndProgramStmt>(func)} {1763  const auto &programStmt =1764      std::get<std::optional<parser::Statement<parser::ProgramStmt>>>(func.t);1765  if (programStmt.has_value()) {1766    beginStmt = FunctionStatement(programStmt.value());1767    const semantics::Symbol *symbol = getSymbol(*beginStmt);1768    entryPointList[0].first = symbol;1769    scope = symbol->scope();1770  } else {1771    scope = &semanticsContext.FindScope(1772        std::get<parser::Statement<parser::EndProgramStmt>>(func.t).source);1773  }1774}1775 1776Fortran::lower::pft::FunctionLikeUnit::FunctionLikeUnit(1777    const parser::FunctionSubprogram &func, const lower::pft::PftNode &parent,1778    const semantics::SemanticsContext &)1779    : ProgramUnit{func, parent},1780      beginStmt{getFunctionStmt<parser::FunctionStmt>(func)},1781      endStmt{getFunctionStmt<parser::EndFunctionStmt>(func)} {1782  const semantics::Symbol *symbol = getSymbol(*beginStmt);1783  entryPointList[0].first = symbol;1784  scope = symbol->scope();1785}1786 1787Fortran::lower::pft::FunctionLikeUnit::FunctionLikeUnit(1788    const parser::SubroutineSubprogram &func, const lower::pft::PftNode &parent,1789    const semantics::SemanticsContext &)1790    : ProgramUnit{func, parent},1791      beginStmt{getFunctionStmt<parser::SubroutineStmt>(func)},1792      endStmt{getFunctionStmt<parser::EndSubroutineStmt>(func)} {1793  const semantics::Symbol *symbol = getSymbol(*beginStmt);1794  entryPointList[0].first = symbol;1795  scope = symbol->scope();1796}1797 1798Fortran::lower::pft::FunctionLikeUnit::FunctionLikeUnit(1799    const parser::SeparateModuleSubprogram &func,1800    const lower::pft::PftNode &parent, const semantics::SemanticsContext &)1801    : ProgramUnit{func, parent},1802      beginStmt{getFunctionStmt<parser::MpSubprogramStmt>(func)},1803      endStmt{getFunctionStmt<parser::EndMpSubprogramStmt>(func)} {1804  const semantics::Symbol *symbol = getSymbol(*beginStmt);1805  entryPointList[0].first = symbol;1806  scope = symbol->scope();1807}1808 1809Fortran::lower::HostAssociations &1810Fortran::lower::pft::FunctionLikeUnit::parentHostAssoc() {1811  if (auto *par = parent.getIf<FunctionLikeUnit>())1812    return par->hostAssociations;1813  llvm::report_fatal_error("parent is not a function");1814}1815 1816bool Fortran::lower::pft::FunctionLikeUnit::parentHasTupleHostAssoc() {1817  if (auto *par = parent.getIf<FunctionLikeUnit>())1818    return par->hostAssociations.hasTupleAssociations();1819  return false;1820}1821 1822bool Fortran::lower::pft::FunctionLikeUnit::parentHasHostAssoc() {1823  if (auto *par = parent.getIf<FunctionLikeUnit>())1824    return !par->hostAssociations.empty();1825  return false;1826}1827 1828parser::CharBlock1829Fortran::lower::pft::FunctionLikeUnit::getStartingSourceLoc() const {1830  if (beginStmt)1831    return stmtSourceLoc(*beginStmt);1832  return scope->sourceRange();1833}1834 1835//===----------------------------------------------------------------------===//1836// ModuleLikeUnit implementation1837//===----------------------------------------------------------------------===//1838 1839Fortran::lower::pft::ModuleLikeUnit::ModuleLikeUnit(1840    const parser::Module &m, const lower::pft::PftNode &parent)1841    : ProgramUnit{m, parent}, beginStmt{getModuleStmt<parser::ModuleStmt>(m)},1842      endStmt{getModuleStmt<parser::EndModuleStmt>(m)} {}1843 1844Fortran::lower::pft::ModuleLikeUnit::ModuleLikeUnit(1845    const parser::Submodule &m, const lower::pft::PftNode &parent)1846    : ProgramUnit{m, parent},1847      beginStmt{getModuleStmt<parser::SubmoduleStmt>(m)},1848      endStmt{getModuleStmt<parser::EndSubmoduleStmt>(m)} {}1849 1850parser::CharBlock1851Fortran::lower::pft::ModuleLikeUnit::getStartingSourceLoc() const {1852  return stmtSourceLoc(beginStmt);1853}1854const Fortran::semantics::Scope &1855Fortran::lower::pft::ModuleLikeUnit::getScope() const {1856  const Fortran::semantics::Symbol *symbol = getSymbol(beginStmt);1857  assert(symbol && symbol->scope() &&1858         "Module statement must have a symbol with a scope");1859  return *symbol->scope();1860}1861 1862//===----------------------------------------------------------------------===//1863// BlockDataUnit implementation1864//===----------------------------------------------------------------------===//1865 1866Fortran::lower::pft::BlockDataUnit::BlockDataUnit(1867    const parser::BlockData &bd, const lower::pft::PftNode &parent,1868    const semantics::SemanticsContext &semanticsContext)1869    : ProgramUnit{bd, parent},1870      symTab{semanticsContext.FindScope(1871          std::get<parser::Statement<parser::EndBlockDataStmt>>(bd.t).source)} {1872}1873 1874//===----------------------------------------------------------------------===//1875// Variable implementation1876//===----------------------------------------------------------------------===//1877 1878bool Fortran::lower::pft::Variable::isRuntimeTypeInfoData() const {1879  // So far, use flags to detect if this symbol were generated during1880  // semantics::BuildRuntimeDerivedTypeTables(). Scope cannot be used since the1881  // symbols are injected in the user scopes defining the described derived1882  // types. A robustness improvement for this test could be to get hands on the1883  // semantics::RuntimeDerivedTypeTables and to check if the symbol names1884  // belongs to this structure.1885  using Flags = Fortran::semantics::Symbol::Flag;1886  const auto *nominal = std::get_if<Nominal>(&var);1887  return nominal && nominal->symbol->test(Flags::CompilerCreated) &&1888         nominal->symbol->test(Flags::ReadOnly);1889}1890 1891//===----------------------------------------------------------------------===//1892// API implementation1893//===----------------------------------------------------------------------===//1894 1895std::unique_ptr<lower::pft::Program>1896Fortran::lower::createPFT(const parser::Program &root,1897                          const semantics::SemanticsContext &semanticsContext) {1898  PFTBuilder walker(semanticsContext);1899  Walk(root, walker);1900  return walker.result();1901}1902 1903void Fortran::lower::dumpPFT(llvm::raw_ostream &outputStream,1904                             const lower::pft::Program &pft) {1905  PFTDumper{}.dumpPFT(outputStream, pft);1906}1907 1908void Fortran::lower::pft::Program::dump() const {1909  dumpPFT(llvm::errs(), *this);1910}1911 1912void Fortran::lower::pft::Evaluation::dump() const {1913  PFTDumper{}.dumpEvaluation(llvm::errs(), *this);1914}1915 1916void Fortran::lower::pft::Variable::dump() const {1917  if (auto *s = std::get_if<Nominal>(&var)) {1918    llvm::errs() << s->symbol << " " << *s->symbol;1919    llvm::errs() << " (depth: " << s->depth << ')';1920    if (s->global)1921      llvm::errs() << ", global";1922    if (s->heapAlloc)1923      llvm::errs() << ", allocatable";1924    if (s->pointer)1925      llvm::errs() << ", pointer";1926    if (s->target)1927      llvm::errs() << ", target";1928    if (s->aliaser)1929      llvm::errs() << ", equivalence(" << s->aliasOffset << ')';1930  } else if (auto *s = std::get_if<AggregateStore>(&var)) {1931    llvm::errs() << "interval[" << std::get<0>(s->interval) << ", "1932                 << std::get<1>(s->interval) << "]:";1933    llvm::errs() << " name: " << toStringRef(s->getNamingSymbol().name());1934    if (s->isGlobal())1935      llvm::errs() << ", global";1936    if (s->initialValueSymbol)1937      llvm::errs() << ", initial value: {" << *s->initialValueSymbol << "}";1938  } else {1939    llvm_unreachable("not a Variable");1940  }1941  llvm::errs() << '\n';1942}1943 1944void Fortran::lower::pft::dump(Fortran::lower::pft::VariableList &variableList,1945                               std::string s) {1946  llvm::errs() << (s.empty() ? "VariableList" : s) << " " << &variableList1947               << " size=" << variableList.size() << "\n";1948  for (auto var : variableList) {1949    llvm::errs() << "  ";1950    var.dump();1951  }1952}1953 1954void Fortran::lower::pft::FunctionLikeUnit::dump() const {1955  PFTDumper{}.dumpFunctionLikeUnit(llvm::errs(), *this);1956}1957 1958void Fortran::lower::pft::ModuleLikeUnit::dump() const {1959  PFTDumper{}.dumpModuleLikeUnit(llvm::errs(), *this);1960}1961 1962/// The BlockDataUnit dump is just the associated symbol table.1963void Fortran::lower::pft::BlockDataUnit::dump() const {1964  llvm::errs() << "block data {\n" << symTab << "\n}\n";1965}1966 1967/// Find or create an ordered list of equivalences and variables in \p scope.1968/// The result is cached in \p map.1969const lower::pft::VariableList &1970lower::pft::getScopeVariableList(const semantics::Scope &scope,1971                                 ScopeVariableListMap &map) {1972  LLVM_DEBUG(llvm::dbgs() << "\ngetScopeVariableList of [sub]module scope <"1973                          << &scope << "> " << scope.GetName() << "\n");1974  auto iter = map.find(&scope);1975  if (iter == map.end()) {1976    SymbolDependenceAnalysis sda(scope);1977    map.emplace(&scope, sda.getVariableList());1978    iter = map.find(&scope);1979  }1980  return iter->second;1981}1982 1983/// Create an ordered list of equivalences and variables in \p scope.1984/// The result is not cached.1985lower::pft::VariableList1986lower::pft::getScopeVariableList(const semantics::Scope &scope) {1987  LLVM_DEBUG(1988      llvm::dbgs() << "\ngetScopeVariableList of [sub]program|block scope <"1989                   << &scope << "> " << scope.GetName() << "\n");1990  SymbolDependenceAnalysis sda(scope);1991  return sda.getVariableList();1992}1993 1994/// Create an ordered list of equivalences and variables that \p symbol1995/// depends on (no caching). Include \p symbol at the end of the list.1996lower::pft::VariableList1997lower::pft::getDependentVariableList(const semantics::Symbol &symbol) {1998  LLVM_DEBUG(llvm::dbgs() << "\ngetDependentVariableList of " << &symbol1999                          << " - " << symbol << "\n");2000  SymbolDependenceAnalysis sda(symbol);2001  return sda.getVariableList();2002}2003 2004namespace {2005/// Helper class to find all the symbols referenced in a FunctionLikeUnit.2006/// It defines a parse tree visitor doing a deep visit in all nodes with2007/// symbols (including evaluate::Expr).2008struct SymbolVisitor {2009  template <typename A>2010  bool Pre(const A &x) {2011    if constexpr (Fortran::parser::HasTypedExpr<A>::value)2012      // Some parse tree Expr may legitimately be un-analyzed after semantics2013      // (for instance PDT component initial value in the PDT definition body).2014      if (const auto *expr = Fortran::semantics::GetExpr(nullptr, x))2015        visitExpr(*expr);2016    return true;2017  }2018 2019  bool Pre(const Fortran::parser::Name &name) {2020    if (const semantics::Symbol *symbol = name.symbol)2021      visitSymbol(*symbol);2022    return false;2023  }2024 2025  template <typename T>2026  void visitExpr(const Fortran::evaluate::Expr<T> &expr) {2027    for (const semantics::Symbol &symbol :2028         Fortran::evaluate::CollectSymbols(expr))2029      visitSymbol(symbol);2030  }2031 2032  void visitSymbol(const Fortran::semantics::Symbol &symbol) {2033    callBack(symbol);2034    // - Visit statement function body since it will be inlined in lowering.2035    // - Visit function results specification expressions because allocations2036    //   happens on the caller side.2037    if (const auto *subprogramDetails =2038            symbol.detailsIf<Fortran::semantics::SubprogramDetails>()) {2039      if (const auto &maybeExpr = subprogramDetails->stmtFunction()) {2040        visitExpr(*maybeExpr);2041      } else {2042        if (subprogramDetails->isFunction()) {2043          // Visit result extents expressions that are explicit.2044          const Fortran::semantics::Symbol &result =2045              subprogramDetails->result();2046          if (const auto *objectDetails =2047                  result.detailsIf<Fortran::semantics::ObjectEntityDetails>())2048            if (objectDetails->shape().IsExplicitShape())2049              for (const Fortran::semantics::ShapeSpec &shapeSpec :2050                   objectDetails->shape()) {2051                visitExpr(shapeSpec.lbound().GetExplicit().value());2052                visitExpr(shapeSpec.ubound().GetExplicit().value());2053              }2054        }2055      }2056    }2057    if (Fortran::semantics::IsProcedure(symbol)) {2058      if (auto dynamicType = Fortran::evaluate::DynamicType::From(symbol)) {2059        // Visit result length specification expressions that are explicit.2060        if (dynamicType->category() ==2061            Fortran::common::TypeCategory::Character) {2062          if (std::optional<Fortran::evaluate::ExtentExpr> length =2063                  dynamicType->GetCharLength())2064            visitExpr(*length);2065        } else if (const Fortran::semantics::DerivedTypeSpec *derivedTypeSpec =2066                       Fortran::evaluate::GetDerivedTypeSpec(dynamicType)) {2067          for (const auto &[_, param] : derivedTypeSpec->parameters())2068            if (const Fortran::semantics::MaybeIntExpr &expr =2069                    param.GetExplicit())2070              visitExpr(expr.value());2071        }2072      }2073    }2074    // - CrayPointer needs to be available whenever a CrayPointee is used.2075    if (symbol.GetUltimate().test(2076            Fortran::semantics::Symbol::Flag::CrayPointee))2077      visitSymbol(Fortran::semantics::GetCrayPointer(symbol));2078  }2079 2080  template <typename A>2081  constexpr void Post(const A &) {}2082 2083  const std::function<void(const Fortran::semantics::Symbol &)> &callBack;2084};2085} // namespace2086 2087void Fortran::lower::pft::visitAllSymbols(2088    const Fortran::lower::pft::FunctionLikeUnit &funit,2089    const std::function<void(const Fortran::semantics::Symbol &)> callBack) {2090  SymbolVisitor visitor{callBack};2091  funit.visit([&](const auto &functionParserNode) {2092    parser::Walk(functionParserNode, visitor);2093  });2094}2095 2096void Fortran::lower::pft::visitAllSymbols(2097    const Fortran::lower::pft::Evaluation &eval,2098    const std::function<void(const Fortran::semantics::Symbol &)> callBack) {2099  SymbolVisitor visitor{callBack};2100  eval.visit([&](const auto &functionParserNode) {2101    parser::Walk(functionParserNode, visitor);2102  });2103}2104