//===-- lib/Semantics/resolve-labels.cpp ----------------------------------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
#include "resolve-labels.h"
#include "flang/Common/enum-set.h"
#include "flang/Common/template.h"
#include "flang/Parser/parse-tree-visitor.h"
#include "flang/Semantics/semantics.h"
#include <cstdarg>
#include <type_traits>
namespace Fortran::semantics {
using namespace parser::literals;
ENUM_CLASS(
TargetStatementEnum, Do, Branch, Format, CompatibleDo, CompatibleBranch)
using LabeledStmtClassificationSet =
common::EnumSet<TargetStatementEnum, TargetStatementEnum_enumSize>;
using IndexList = std::vector<std::pair<parser::CharBlock, parser::CharBlock>>;
// A ProxyForScope is an integral proxy for a Fortran scope. This is required
// because the parse tree does not actually have the scopes required.
using ProxyForScope = unsigned;
// Minimal scope information
struct ScopeInfo {
ProxyForScope parent{};
bool isExteriorGotoFatal{false};
int depth{0};
};
struct LabeledStatementInfoTuplePOD {
ProxyForScope proxyForScope;
parser::CharBlock parserCharBlock;
LabeledStmtClassificationSet labeledStmtClassificationSet;
bool isExecutableConstructEndStmt;
};
using TargetStmtMap = std::map<parser::Label, LabeledStatementInfoTuplePOD>;
struct SourceStatementInfoTuplePOD {
SourceStatementInfoTuplePOD(const parser::Label &parserLabel,
const ProxyForScope &proxyForScope,
const parser::CharBlock &parserCharBlock)
: parserLabel{parserLabel}, proxyForScope{proxyForScope},
parserCharBlock{parserCharBlock} {}
parser::Label parserLabel;
ProxyForScope proxyForScope;
parser::CharBlock parserCharBlock;
};
using SourceStmtList = std::vector<SourceStatementInfoTuplePOD>;
enum class Legality { never, always, formerly };
bool HasScope(ProxyForScope scope) { return scope != ProxyForScope{0u}; }
// F18:R1131
template <typename A>
constexpr Legality IsLegalDoTerm(const parser::Statement<A> &) {
if (std::is_same_v<A, common::Indirection<parser::EndDoStmt>> ||
std::is_same_v<A, parser::EndDoStmt>) {
return Legality::always;
} else if (std::is_same_v<A, parser::EndForallStmt> ||
std::is_same_v<A, parser::EndWhereStmt>) {
// Executable construct end statements are also supported as
// an extension but they need special care because the associated
// construct create their own scope.
return Legality::formerly;
} else {
return Legality::never;
}
}
constexpr Legality IsLegalDoTerm(
const parser::Statement<parser::ActionStmt> &actionStmt) {
if (std::holds_alternative<parser::ContinueStmt>(actionStmt.statement.u)) {
// See F08:C816
return Legality::always;
} else if (!(std::holds_alternative<
common::Indirection<parser::ArithmeticIfStmt>>(
actionStmt.statement.u) ||
std::holds_alternative<common::Indirection<parser::CycleStmt>>(
actionStmt.statement.u) ||
std::holds_alternative<common::Indirection<parser::ExitStmt>>(
actionStmt.statement.u) ||
std::holds_alternative<common::Indirection<parser::StopStmt>>(
actionStmt.statement.u) ||
std::holds_alternative<common::Indirection<parser::GotoStmt>>(
actionStmt.statement.u) ||
std::holds_alternative<
common::Indirection<parser::ReturnStmt>>(
actionStmt.statement.u))) {
return Legality::formerly;
} else {
return Legality::never;
}
}
template <typename A> constexpr bool IsFormat(const parser::Statement<A> &) {
return std::is_same_v<A, common::Indirection<parser::FormatStmt>>;
}
template <typename A>
constexpr Legality IsLegalBranchTarget(const parser::Statement<A> &) {
if (std::is_same_v<A, parser::ActionStmt> ||
std::is_same_v<A, parser::AssociateStmt> ||
std::is_same_v<A, parser::EndAssociateStmt> ||
std::is_same_v<A, parser::IfThenStmt> ||
std::is_same_v<A, parser::EndIfStmt> ||
std::is_same_v<A, parser::SelectCaseStmt> ||
std::is_same_v<A, parser::EndSelectStmt> ||
std::is_same_v<A, parser::SelectRankStmt> ||
std::is_same_v<A, parser::SelectTypeStmt> ||
std::is_same_v<A, common::Indirection<parser::LabelDoStmt>> ||
std::is_same_v<A, parser::NonLabelDoStmt> ||
std::is_same_v<A, parser::EndDoStmt> ||
std::is_same_v<A, common::Indirection<parser::EndDoStmt>> ||
std::is_same_v<A, parser::BlockStmt> ||
std::is_same_v<A, parser::EndBlockStmt> ||
std::is_same_v<A, parser::CriticalStmt> ||
std::is_same_v<A, parser::EndCriticalStmt> ||
std::is_same_v<A, parser::ForallConstructStmt> ||
std::is_same_v<A, parser::WhereConstructStmt> ||
std::is_same_v<A, parser::EndFunctionStmt> ||
std::is_same_v<A, parser::EndMpSubprogramStmt> ||
std::is_same_v<A, parser::EndProgramStmt> ||
std::is_same_v<A, parser::EndSubroutineStmt>) {
return Legality::always;
} else {
return Legality::never;
}
}
template <typename A>
constexpr LabeledStmtClassificationSet ConstructBranchTargetFlags(
const parser::Statement<A> &statement) {
LabeledStmtClassificationSet labeledStmtClassificationSet{};
if (IsLegalDoTerm(statement) == Legality::always) {
labeledStmtClassificationSet.set(TargetStatementEnum::Do);
} else if (IsLegalDoTerm(statement) == Legality::formerly) {
labeledStmtClassificationSet.set(TargetStatementEnum::CompatibleDo);
}
if (IsLegalBranchTarget(statement) == Legality::always) {
labeledStmtClassificationSet.set(TargetStatementEnum::Branch);
} else if (IsLegalBranchTarget(statement) == Legality::formerly) {
labeledStmtClassificationSet.set(TargetStatementEnum::CompatibleBranch);
}
if (IsFormat(statement)) {
labeledStmtClassificationSet.set(TargetStatementEnum::Format);
}
return labeledStmtClassificationSet;
}
static unsigned SayLabel(parser::Label label) {
return static_cast<unsigned>(label);
}
struct UnitAnalysis {
UnitAnalysis() { scopeModel.emplace_back(); }
SourceStmtList doStmtSources;
SourceStmtList formatStmtSources;
SourceStmtList otherStmtSources;
SourceStmtList assignStmtSources;
TargetStmtMap targetStmts;
std::vector<ScopeInfo> scopeModel;
};
// Some parse tree record for statements simply wrap construct names;
// others include them as tuple components. Given a statement,
// return a pointer to its name if it has one.
template <typename A>
const parser::CharBlock *GetStmtName(const parser::Statement<A> &stmt) {
const std::optional<parser::Name> *name{nullptr};
if constexpr (WrapperTrait<A>) {
if constexpr (std::is_same_v<decltype(A::v), parser::Name>) {
return &stmt.statement.v.source;
} else {
name = &stmt.statement.v;
}
} else if constexpr (std::is_same_v<A, parser::SelectRankStmt> ||
std::is_same_v<A, parser::SelectTypeStmt>) {
name = &std::get<0>(stmt.statement.t);
} else if constexpr (common::HasMember<parser::Name,
decltype(stmt.statement.t)>) {
return &std::get<parser::Name>(stmt.statement.t).source;
} else {
name = &std::get<std::optional<parser::Name>>(stmt.statement.t);
}
if (name && *name) {
return &(*name)->source;
}
return nullptr;
}
class ParseTreeAnalyzer {
public:
ParseTreeAnalyzer(ParseTreeAnalyzer &&that) = default;
ParseTreeAnalyzer(SemanticsContext &context) : context_{context} {}
template <typename A> constexpr bool Pre(const A &x) {
using LabeledProgramUnitStmts =
std::tuple<parser::MainProgram, parser::FunctionSubprogram,
parser::SubroutineSubprogram, parser::SeparateModuleSubprogram>;
if constexpr (common::HasMember<A, LabeledProgramUnitStmts>) {
const auto &endStmt{std::get<std::tuple_size_v<decltype(x.t)> - 1>(x.t)};
if (endStmt.label) {
// The END statement for a subprogram appears after any internal
// subprograms. Visit that statement in advance so that results
// are placed in the correct programUnits_ slot.
auto targetFlags{ConstructBranchTargetFlags(endStmt)};
AddTargetLabelDefinition(
endStmt.label.value(), targetFlags, currentScope_);
}
}
return true;
}
template <typename A> constexpr void Post(const A &) {}
template <typename A> bool Pre(const parser::Statement<A> &statement) {
currentPosition_ = statement.source;
const auto &label = statement.label;
if (!label) {
return true;
}
using LabeledConstructStmts = std::tuple<parser::AssociateStmt,
parser::BlockStmt, parser::ChangeTeamStmt, parser::CriticalStmt,
parser::IfThenStmt, parser::NonLabelDoStmt, parser::SelectCaseStmt,
parser::SelectRankStmt, parser::SelectTypeStmt,
parser::ForallConstructStmt, parser::WhereConstructStmt>;
using LabeledConstructEndStmts = std::tuple<parser::EndAssociateStmt,
parser::EndBlockStmt, parser::EndChangeTeamStmt,
parser::EndCriticalStmt, parser::EndDoStmt, parser::EndForallStmt,
parser::EndIfStmt, parser::EndWhereStmt>;
using LabeledProgramUnitEndStmts =
std::tuple<parser::EndFunctionStmt, parser::EndMpSubprogramStmt,
parser::EndProgramStmt, parser::EndSubroutineStmt>;
auto targetFlags{ConstructBranchTargetFlags(statement)};
if constexpr (common::HasMember<A, LabeledConstructStmts>) {
AddTargetLabelDefinition(label.value(), targetFlags, ParentScope());
} else if constexpr (std::is_same_v<A, parser::EndIfStmt> ||
std::is_same_v<A, parser::EndSelectStmt>) {
// the label on an END IF/SELECT is not in the last part/case
AddTargetLabelDefinition(label.value(), targetFlags, ParentScope(), true);
} else if constexpr (common::HasMember<A, LabeledConstructEndStmts>) {
constexpr bool isExecutableConstructEndStmt{true};
AddTargetLabelDefinition(label.value(), targetFlags, currentScope_,
isExecutableConstructEndStmt);
} else if constexpr (!common::HasMember<A, LabeledProgramUnitEndStmts>) {
// Program unit END statements have already been processed.
AddTargetLabelDefinition(label.value(), targetFlags, currentScope_);
}
return true;
}
// see 11.1.1
bool Pre(const parser::ProgramUnit &) { return InitializeNewScopeContext(); }
bool Pre(const parser::InternalSubprogram &) {
return InitializeNewScopeContext();
}
bool Pre(const parser::ModuleSubprogram &) {
return InitializeNewScopeContext();
}
bool Pre(const parser::AssociateConstruct &associateConstruct) {
return PushConstructName(associateConstruct);
}
bool Pre(const parser::BlockConstruct &blockConstruct) {
return PushConstructName(blockConstruct);
}
bool Pre(const parser::ChangeTeamConstruct &changeTeamConstruct) {
return PushConstructName(changeTeamConstruct);
}
bool Pre(const parser::CriticalConstruct &criticalConstruct) {
return PushConstructName(criticalConstruct);
}
bool Pre(const parser::DoConstruct &doConstruct) {
const auto &optionalName{std::get<std::optional<parser::Name>>(
std::get<parser::Statement<parser::NonLabelDoStmt>>(doConstruct.t)
.statement.t)};
if (optionalName) {
constructNames_.emplace_back(optionalName->ToString());
}
// Allow FORTRAN '66 extended DO ranges
PushScope(false);
// Process labels of the DO and END DO statements, but not the
// statements themselves, so that a non-construct END DO
// can be distinguished (below).
Pre(std::get<parser::Statement<parser::NonLabelDoStmt>>(doConstruct.t));
Walk(std::get<parser::Block>(doConstruct.t), *this);
Pre(std::get<parser::Statement<parser::EndDoStmt>>(doConstruct.t));
PopConstructName(doConstruct);
return false;
}
void Post(const parser::EndDoStmt &endDoStmt) {
// Visited only for non-construct labeled DO termination
if (const auto &name{endDoStmt.v}) {
context_.Say(name->source, "Unexpected DO construct name '%s'"_err_en_US,
name->source);
}
}
bool Pre(const parser::IfConstruct &ifConstruct) {
return PushConstructName(ifConstruct);
}
void Post(const parser::IfThenStmt &) { PushScope(false); }
bool Pre(const parser::IfConstruct::ElseIfBlock &) {
return SwitchToNewScope();
}
bool Pre(const parser::IfConstruct::ElseBlock &) {
return SwitchToNewScope();
}
bool Pre(const parser::EndIfStmt &) {
PopScope();
return true;
}
bool Pre(const parser::CaseConstruct &caseConstruct) {
return PushConstructName(caseConstruct);
}
void Post(const parser::SelectCaseStmt &) { PushScope(false); }
bool Pre(const parser::CaseConstruct::Case &) { return SwitchToNewScope(); }
bool Pre(const parser::SelectRankConstruct &selectRankConstruct) {
return PushConstructName(selectRankConstruct);
}
void Post(const parser::SelectRankStmt &) { PushScope(true); }
bool Pre(const parser::SelectRankConstruct::RankCase &) {
return SwitchToNewScope();
}
bool Pre(const parser::SelectTypeConstruct &selectTypeConstruct) {
return PushConstructName(selectTypeConstruct);
}
void Post(const parser::SelectTypeStmt &) { PushScope(true); }
bool Pre(const parser::SelectTypeConstruct::TypeCase &) {
return SwitchToNewScope();
}
void Post(const parser::EndSelectStmt &) { PopScope(); }
bool Pre(const parser::WhereConstruct &whereConstruct) {
return PushConstructName(whereConstruct);
}
bool Pre(const parser::ForallConstruct &forallConstruct) {
return PushConstructName(forallConstruct);
}
void Post(const parser::AssociateConstruct &associateConstruct) {
PopConstructName(associateConstruct);
}
void Post(const parser::BlockConstruct &blockConstruct) {
PopConstructName(blockConstruct);
}
void Post(const parser::ChangeTeamConstruct &changeTeamConstruct) {
PopConstructName(changeTeamConstruct);
}
void Post(const parser::CriticalConstruct &criticalConstruct) {
PopConstructName(criticalConstruct);
}
void Post(const parser::IfConstruct &ifConstruct) {
PopConstructName(ifConstruct);
}
void Post(const parser::CaseConstruct &caseConstruct) {
PopConstructName(caseConstruct);
}
void Post(const parser::SelectRankConstruct &selectRankConstruct) {
PopConstructName(selectRankConstruct);
}
void Post(const parser::SelectTypeConstruct &selectTypeConstruct) {
PopConstructName(selectTypeConstruct);
}
void Post(const parser::WhereConstruct &whereConstruct) {
PopConstructName(whereConstruct);
}
void Post(const parser::ForallConstruct &forallConstruct) {
PopConstructName(forallConstruct);
}
// Checks for missing or mismatching names on various constructs (e.g., IF)
// and their intermediate or terminal statements that allow optional
// construct names(e.g., ELSE). When an optional construct name is present,
// the construct as a whole must have a name that matches.
template <typename FIRST, typename CONSTRUCT, typename STMT>
void CheckOptionalName(const char *constructTag, const CONSTRUCT &a,
const parser::Statement<STMT> &stmt) {
if (const parser::CharBlock * name{GetStmtName(stmt)}) {
const auto &firstStmt{std::get<parser::Statement<FIRST>>(a.t)};
if (const parser::CharBlock * firstName{GetStmtName(firstStmt)}) {
if (*firstName != *name) {
context_.Say(*name, "%s name mismatch"_err_en_US, constructTag)
.Attach(*firstName, "should be"_en_US);
}
} else {
context_.Say(*name, "%s name not allowed"_err_en_US, constructTag)
.Attach(firstStmt.source, "in unnamed %s"_en_US, constructTag);
}
}
}
// C1414
void Post(const parser::BlockData &blockData) {
CheckOptionalName<parser::BlockDataStmt>("BLOCK DATA subprogram", blockData,
std::get<parser::Statement<parser::EndBlockDataStmt>>(blockData.t));
}
bool Pre(const parser::InterfaceBody &) {
PushDisposableMap();
return true;
}
void Post(const parser::InterfaceBody &) { PopDisposableMap(); }
// C1564
void Post(const parser::InterfaceBody::Function &func) {
CheckOptionalName<parser::FunctionStmt>("FUNCTION", func,
std::get<parser::Statement<parser::EndFunctionStmt>>(func.t));
}
// C1564
void Post(const parser::FunctionSubprogram &functionSubprogram) {
CheckOptionalName<parser::FunctionStmt>("FUNCTION", functionSubprogram,
std::get<parser::Statement<parser::EndFunctionStmt>>(
functionSubprogram.t));
}
// C1502
void Post(const parser::InterfaceBlock &interfaceBlock) {
if (const auto &endGenericSpec{
std::get<parser::Statement<parser::EndInterfaceStmt>>(
interfaceBlock.t)
.statement.v}) {
const auto &interfaceStmt{
std::get<parser::Statement<parser::InterfaceStmt>>(interfaceBlock.t)};
if (std::holds_alternative<parser::Abstract>(interfaceStmt.statement.u)) {
context_
.Say(endGenericSpec->source,
"END INTERFACE generic name (%s) may not appear for ABSTRACT INTERFACE"_err_en_US,
endGenericSpec->source)
.Attach(
interfaceStmt.source, "corresponding ABSTRACT INTERFACE"_en_US);
} else if (const auto &genericSpec{
std::get<std::optional<parser::GenericSpec>>(
interfaceStmt.statement.u)}) {
bool ok{genericSpec->source == endGenericSpec->source};
if (!ok) {
// Accept variant spellings of .LT. &c.
const auto *endOp{
std::get_if<parser::DefinedOperator>(&endGenericSpec->u)};
const auto *op{std::get_if<parser::DefinedOperator>(&genericSpec->u)};
if (endOp && op) {
const auto *endIntrin{
std::get_if<parser::DefinedOperator::IntrinsicOperator>(
&endOp->u)};
const auto *intrin{
std::get_if<parser::DefinedOperator::IntrinsicOperator>(
&op->u)};
ok = endIntrin && intrin && *endIntrin == *intrin;
}
}
if (!ok) {
context_
.Say(endGenericSpec->source,
"END INTERFACE generic name (%s) does not match generic INTERFACE (%s)"_err_en_US,
endGenericSpec->source, genericSpec->source)
.Attach(genericSpec->source, "corresponding INTERFACE"_en_US);
}
} else {
context_
.Say(endGenericSpec->source,
"END INTERFACE generic name (%s) may not appear for non-generic INTERFACE"_err_en_US,
endGenericSpec->source)
.Attach(interfaceStmt.source, "corresponding INTERFACE"_en_US);
}
}
}
// C1402
void Post(const parser::Module &module) {
CheckOptionalName<parser::ModuleStmt>("MODULE", module,
std::get<parser::Statement<parser::EndModuleStmt>>(module.t));
}
// C1569
void Post(const parser::SeparateModuleSubprogram &separateModuleSubprogram) {
CheckOptionalName<parser::MpSubprogramStmt>("MODULE PROCEDURE",
separateModuleSubprogram,
std::get<parser::Statement<parser::EndMpSubprogramStmt>>(
separateModuleSubprogram.t));
}
// C1401
void Post(const parser::MainProgram &mainProgram) {
if (const parser::CharBlock *
endName{GetStmtName(std::get<parser::Statement<parser::EndProgramStmt>>(
mainProgram.t))}) {
if (const auto &program{
std::get<std::optional<parser::Statement<parser::ProgramStmt>>>(
mainProgram.t)}) {
if (*endName != program->statement.v.source) {
context_.Say(*endName, "END PROGRAM name mismatch"_err_en_US)
.Attach(program->statement.v.source, "should be"_en_US);
}
} else {
context_.Say(*endName,
"END PROGRAM has name without PROGRAM statement"_err_en_US);
}
}
}
// C1413
void Post(const parser::Submodule &submodule) {
CheckOptionalName<parser::SubmoduleStmt>("SUBMODULE", submodule,
std::get<parser::Statement<parser::EndSubmoduleStmt>>(submodule.t));
}
// C1567
void Post(const parser::InterfaceBody::Subroutine &sub) {
CheckOptionalName<parser::SubroutineStmt>("SUBROUTINE", sub,
std::get<parser::Statement<parser::EndSubroutineStmt>>(sub.t));
}
// C1567
void Post(const parser::SubroutineSubprogram &subroutineSubprogram) {
CheckOptionalName<parser::SubroutineStmt>("SUBROUTINE",
subroutineSubprogram,
std::get<parser::Statement<parser::EndSubroutineStmt>>(
subroutineSubprogram.t));
}
// C739
bool Pre(const parser::DerivedTypeDef &) {
PushDisposableMap();
return true;
}
void Post(const parser::DerivedTypeDef &derivedTypeDef) {
CheckOptionalName<parser::DerivedTypeStmt>("derived type definition",
derivedTypeDef,
std::get<parser::Statement<parser::EndTypeStmt>>(derivedTypeDef.t));
PopDisposableMap();
}
void Post(const parser::LabelDoStmt &labelDoStmt) {
AddLabelReferenceFromDoStmt(std::get<parser::Label>(labelDoStmt.t));
}
void Post(const parser::GotoStmt &gotoStmt) { AddLabelReference(gotoStmt.v); }
void Post(const parser::ComputedGotoStmt &computedGotoStmt) {
AddLabelReference(std::get<std::list<parser::Label>>(computedGotoStmt.t));
}
void Post(const parser::ArithmeticIfStmt &arithmeticIfStmt) {
AddLabelReference(std::get<1>(arithmeticIfStmt.t));
AddLabelReference(std::get<2>(arithmeticIfStmt.t));
AddLabelReference(std::get<3>(arithmeticIfStmt.t));
}
void Post(const parser::AssignStmt &assignStmt) {
AddLabelReferenceFromAssignStmt(std::get<parser::Label>(assignStmt.t));
}
void Post(const parser::AssignedGotoStmt &assignedGotoStmt) {
AddLabelReference(std::get<std::list<parser::Label>>(assignedGotoStmt.t));
}
void Post(const parser::AltReturnSpec &altReturnSpec) {
AddLabelReference(altReturnSpec.v);
}
void Post(const parser::ErrLabel &errLabel) { AddLabelReference(errLabel.v); }
void Post(const parser::EndLabel &endLabel) { AddLabelReference(endLabel.v); }
void Post(const parser::EorLabel &eorLabel) { AddLabelReference(eorLabel.v); }
void Post(const parser::Format &format) {
if (const auto *labelPointer{std::get_if<parser::Label>(&format.u)}) {
AddLabelReferenceToFormatStmt(*labelPointer);
}
}
void Post(const parser::CycleStmt &cycleStmt) {
if (cycleStmt.v) {
CheckLabelContext("CYCLE", cycleStmt.v->source);
}
}
void Post(const parser::ExitStmt &exitStmt) {
if (exitStmt.v) {
CheckLabelContext("EXIT", exitStmt.v->source);
}
}
const std::vector<UnitAnalysis> &ProgramUnits() const {
return programUnits_;
}
SemanticsContext &ErrorHandler() { return context_; }
private:
ScopeInfo &PushScope(bool isExteriorGotoFatal) {
auto &model{programUnits_.back().scopeModel};
int newDepth{model.empty() ? 1 : model[currentScope_].depth + 1};
ScopeInfo &result{model.emplace_back()};
result.parent = currentScope_;
result.depth = newDepth;
result.isExteriorGotoFatal = isExteriorGotoFatal;
currentScope_ = model.size() - 1;
return result;
}
bool InitializeNewScopeContext() {
programUnits_.emplace_back(UnitAnalysis{});
currentScope_ = 0u;
PushScope(false);
return true;
}
ScopeInfo &PopScope() {
ScopeInfo &result{programUnits_.back().scopeModel[currentScope_]};
currentScope_ = result.parent;
return result;
}
ProxyForScope ParentScope() {
return programUnits_.back().scopeModel[currentScope_].parent;
}
bool SwitchToNewScope() {
PushScope(PopScope().isExteriorGotoFatal);
return true;
}
template <typename A> bool PushConstructName(const A &a) {
const auto &optionalName{std::get<0>(std::get<0>(a.t).statement.t)};
if (optionalName) {
constructNames_.emplace_back(optionalName->ToString());
}
// Gotos into this construct from outside it are diagnosed, and
// are fatal unless the construct is a DO, IF, or SELECT CASE.
PushScope(!(std::is_same_v<A, parser::DoConstruct> ||
std::is_same_v<A, parser::IfConstruct> ||
std::is_same_v<A, parser::CaseConstruct>));
return true;
}
bool PushConstructName(const parser::BlockConstruct &blockConstruct) {
const auto &optionalName{
std::get<parser::Statement<parser::BlockStmt>>(blockConstruct.t)
.statement.v};
if (optionalName) {
constructNames_.emplace_back(optionalName->ToString());
}
PushScope(true);
return true;
}
template <typename A> void PopConstructNameIfPresent(const A &a) {
const auto &optionalName{std::get<0>(std::get<0>(a.t).statement.t)};
if (optionalName) {
constructNames_.pop_back();
}
}
void PopConstructNameIfPresent(const parser::BlockConstruct &blockConstruct) {
const auto &optionalName{
std::get<parser::Statement<parser::BlockStmt>>(blockConstruct.t)
.statement.v};
if (optionalName) {
constructNames_.pop_back();
}
}
template <typename A> void PopConstructName(const A &a) {
CheckName(a);
PopScope();
PopConstructNameIfPresent(a);
}
template <typename FIRST, typename CASEBLOCK, typename CASE,
typename CONSTRUCT>
void CheckSelectNames(const char *tag, const CONSTRUCT &construct) {
CheckEndName<FIRST, parser::EndSelectStmt>(tag, construct);
for (const auto &inner : std::get<std::list<CASEBLOCK>>(construct.t)) {
CheckOptionalName<FIRST>(
tag, construct, std::get<parser::Statement<CASE>>(inner.t));
}
}
// C1144
void PopConstructName(const parser::CaseConstruct &caseConstruct) {
CheckSelectNames<parser::SelectCaseStmt, parser::CaseConstruct::Case,
parser::CaseStmt>("SELECT CASE", caseConstruct);
PopScope();
PopConstructNameIfPresent(caseConstruct);
}
// C1154, C1156
void PopConstructName(
const parser::SelectRankConstruct &selectRankConstruct) {
CheckSelectNames<parser::SelectRankStmt,
parser::SelectRankConstruct::RankCase, parser::SelectRankCaseStmt>(
"SELECT RANK", selectRankConstruct);
PopScope();
PopConstructNameIfPresent(selectRankConstruct);
}
// C1165
void PopConstructName(
const parser::SelectTypeConstruct &selectTypeConstruct) {
CheckSelectNames<parser::SelectTypeStmt,
parser::SelectTypeConstruct::TypeCase, parser::TypeGuardStmt>(
"SELECT TYPE", selectTypeConstruct);
PopScope();
PopConstructNameIfPresent(selectTypeConstruct);
}
// Checks for missing or mismatching names on various constructs (e.g., BLOCK)
// and their END statements. Both names must be present if either one is.
template <typename FIRST, typename END, typename CONSTRUCT>
void CheckEndName(const char *constructTag, const CONSTRUCT &a) {
const auto &constructStmt{std::get<parser::Statement<FIRST>>(a.t)};
const auto &endStmt{std::get<parser::Statement<END>>(a.t)};
const parser::CharBlock *endName{GetStmtName(endStmt)};
if (const parser::CharBlock * constructName{GetStmtName(constructStmt)}) {
if (endName) {
if (*constructName != *endName) {
context_
.Say(*endName, "%s construct name mismatch"_err_en_US,
constructTag)
.Attach(*constructName, "should be"_en_US);
}
} else {
context_
.Say(endStmt.source,
"%s construct name required but missing"_err_en_US,
constructTag)
.Attach(*constructName, "should be"_en_US);
}
} else if (endName) {
context_
.Say(*endName, "%s construct name unexpected"_err_en_US, constructTag)
.Attach(
constructStmt.source, "unnamed %s statement"_en_US, constructTag);
}
}
// C1106
void CheckName(const parser::AssociateConstruct &associateConstruct) {
CheckEndName<parser::AssociateStmt, parser::EndAssociateStmt>(
"ASSOCIATE", associateConstruct);
}
// C1117
void CheckName(const parser::CriticalConstruct &criticalConstruct) {
CheckEndName<parser::CriticalStmt, parser::EndCriticalStmt>(
"CRITICAL", criticalConstruct);
}
// C1131
void CheckName(const parser::DoConstruct &doConstruct) {
CheckEndName<parser::NonLabelDoStmt, parser::EndDoStmt>("DO", doConstruct);
if (auto label{std::get<std::optional<parser::Label>>(
std::get<parser::Statement<parser::NonLabelDoStmt>>(doConstruct.t)
.statement.t)}) {
const auto &endDoStmt{
std::get<parser::Statement<parser::EndDoStmt>>(doConstruct.t)};
if (!endDoStmt.label || *endDoStmt.label != *label) {
context_
.Say(endDoStmt.source,
"END DO statement must have the label '%d' matching its DO statement"_err_en_US,
*label)
.Attach(std::get<parser::Statement<parser::NonLabelDoStmt>>(
doConstruct.t)
.source,
"corresponding DO statement"_en_US);
}
}
}
// C1035
void CheckName(const parser::ForallConstruct &forallConstruct) {
CheckEndName<parser::ForallConstructStmt, parser::EndForallStmt>(
"FORALL", forallConstruct);
}
// C1109
void CheckName(const parser::BlockConstruct &blockConstruct) {
CheckEndName<parser::BlockStmt, parser::EndBlockStmt>(
"BLOCK", blockConstruct);
}
// C1112
void CheckName(const parser::ChangeTeamConstruct &changeTeamConstruct) {
CheckEndName<parser::ChangeTeamStmt, parser::EndChangeTeamStmt>(
"CHANGE TEAM", changeTeamConstruct);
}
// C1142
void CheckName(const parser::IfConstruct &ifConstruct) {
CheckEndName<parser::IfThenStmt, parser::EndIfStmt>("IF", ifConstruct);
for (const auto &elseIfBlock :
std::get<std::list<parser::IfConstruct::ElseIfBlock>>(ifConstruct.t)) {
CheckOptionalName<parser::IfThenStmt>("IF construct", ifConstruct,
std::get<parser::Statement<parser::ElseIfStmt>>(elseIfBlock.t));
}
if (const auto &elseBlock{
std::get<std::optional<parser::IfConstruct::ElseBlock>>(
ifConstruct.t)}) {
CheckOptionalName<parser::IfThenStmt>("IF construct", ifConstruct,
std::get<parser::Statement<parser::ElseStmt>>(elseBlock->t));
}
}
// C1033
void CheckName(const parser::WhereConstruct &whereConstruct) {
CheckEndName<parser::WhereConstructStmt, parser::EndWhereStmt>(
"WHERE", whereConstruct);
for (const auto &maskedElsewhere :
std::get<std::list<parser::WhereConstruct::MaskedElsewhere>>(
whereConstruct.t)) {
CheckOptionalName<parser::WhereConstructStmt>("WHERE construct",
whereConstruct,
std::get<parser::Statement<parser::MaskedElsewhereStmt>>(
maskedElsewhere.t));
}
if (const auto &elsewhere{
std::get<std::optional<parser::WhereConstruct::Elsewhere>>(
whereConstruct.t)}) {
CheckOptionalName<parser::WhereConstructStmt>("WHERE construct",
whereConstruct,
std::get<parser::Statement<parser::ElsewhereStmt>>(elsewhere->t));
}
}
// C1134, C1166
void CheckLabelContext(
const char *const stmtString, const parser::CharBlock &constructName) {
const auto iter{std::find(constructNames_.crbegin(),
constructNames_.crend(), constructName.ToString())};
if (iter == constructNames_.crend()) {
context_.Say(constructName, "%s construct-name is not in scope"_err_en_US,
stmtString);
}
}
// 6.2.5, paragraph 2
void CheckLabelInRange(parser::Label label) {
if (label < 1 || label > 99999) {
context_.Say(currentPosition_, "Label '%u' is out of range"_err_en_US,
SayLabel(label));
}
}
// 6.2.5., paragraph 2
void AddTargetLabelDefinition(parser::Label label,
LabeledStmtClassificationSet labeledStmtClassificationSet,
ProxyForScope scope, bool isExecutableConstructEndStmt = false) {
CheckLabelInRange(label);
TargetStmtMap &targetStmtMap{disposableMaps_.empty()
? programUnits_.back().targetStmts
: disposableMaps_.back()};
const auto pair{targetStmtMap.emplace(label,
LabeledStatementInfoTuplePOD{scope, currentPosition_,
labeledStmtClassificationSet, isExecutableConstructEndStmt})};
if (!pair.second) {
context_.Say(currentPosition_, "Label '%u' is not distinct"_err_en_US,
SayLabel(label));
}
}
void AddLabelReferenceFromDoStmt(parser::Label label) {
CheckLabelInRange(label);
programUnits_.back().doStmtSources.emplace_back(
label, currentScope_, currentPosition_);
}
void AddLabelReferenceToFormatStmt(parser::Label label) {
CheckLabelInRange(label);
programUnits_.back().formatStmtSources.emplace_back(
label, currentScope_, currentPosition_);
}
void AddLabelReferenceFromAssignStmt(parser::Label label) {
CheckLabelInRange(label);
programUnits_.back().assignStmtSources.emplace_back(
label, currentScope_, currentPosition_);
}
void AddLabelReference(parser::Label label) {
CheckLabelInRange(label);
programUnits_.back().otherStmtSources.emplace_back(
label, currentScope_, currentPosition_);
}
void AddLabelReference(const std::list<parser::Label> &labels) {
for (const parser::Label &label : labels) {
AddLabelReference(label);
}
}
void PushDisposableMap() { disposableMaps_.emplace_back(); }
void PopDisposableMap() { disposableMaps_.pop_back(); }
std::vector<UnitAnalysis> programUnits_;
SemanticsContext &context_;
parser::CharBlock currentPosition_;
ProxyForScope currentScope_;
std::vector<std::string> constructNames_;
// For labels in derived type definitions and procedure
// interfaces, which are their own inclusive scopes. None
// of these labels can be used as a branch target, but they
// should be pairwise distinct.
std::vector<TargetStmtMap> disposableMaps_;
};
bool InInclusiveScope(const std::vector<ScopeInfo> &scopes, ProxyForScope tail,
ProxyForScope head) {
for (; tail != head; tail = scopes[tail].parent) {
if (!HasScope(tail)) {
return false;
}
}
return true;
}
ParseTreeAnalyzer LabelAnalysis(
SemanticsContext &context, const parser::Program &program) {
ParseTreeAnalyzer analysis{context};
Walk(program, analysis);
return analysis;
}
bool InBody(const parser::CharBlock &position,
const std::pair<parser::CharBlock, parser::CharBlock> &pair) {
if (position.begin() >= pair.first.begin()) {
if (position.begin() < pair.second.end()) {
return true;
}
}
return false;
}
LabeledStatementInfoTuplePOD GetLabel(
const TargetStmtMap &labels, const parser::Label &label) {
const auto iter{labels.find(label)};
if (iter == labels.cend()) {
return {0u, nullptr, LabeledStmtClassificationSet{}, false};
} else {
return iter->second;
}
}
// 11.1.7.3
void CheckBranchesIntoDoBody(const SourceStmtList &branches,
const TargetStmtMap &labels, const IndexList &loopBodies,
SemanticsContext &context) {
for (const auto &branch : branches) {
const auto &label{branch.parserLabel};
auto branchTarget{GetLabel(labels, label)};
if (HasScope(branchTarget.proxyForScope)) {
const auto &fromPosition{branch.parserCharBlock};
const auto &toPosition{branchTarget.parserCharBlock};
for (const auto &body : loopBodies) {
if (!InBody(fromPosition, body) && InBody(toPosition, body) &&
context.ShouldWarn(common::LanguageFeature::BranchIntoConstruct)) {
context
.Say(
fromPosition, "branch into loop body from outside"_warn_en_US)
.Attach(body.first, "the loop branched into"_en_US)
.set_languageFeature(
common::LanguageFeature::BranchIntoConstruct);
}
}
}
}
}
void CheckDoNesting(const IndexList &loopBodies, SemanticsContext &context) {
for (auto i1{loopBodies.cbegin()}; i1 != loopBodies.cend(); ++i1) {
const auto &v1{*i1};
for (auto i2{i1 + 1}; i2 != loopBodies.cend(); ++i2) {
const auto &v2{*i2};
if (v2.first.begin() < v1.second.end() &&
v1.second.begin() < v2.second.begin()) {
context.Say(v1.first, "DO loop doesn't properly nest"_err_en_US)
.Attach(v2.first, "DO loop conflicts"_en_US);
}
}
}
}
parser::CharBlock SkipLabel(const parser::CharBlock &position) {
const std::size_t maxPosition{position.size()};
if (maxPosition && parser::IsDecimalDigit(position[0])) {
std::size_t i{1l};
for (; (i < maxPosition) && parser::IsDecimalDigit(position[i]); ++i) {
}
for (; (i < maxPosition) && parser::IsWhiteSpace(position[i]); ++i) {
}
return parser::CharBlock{position.begin() + i, position.end()};
}
return position;
}
ProxyForScope ParentScope(
const std::vector<ScopeInfo> &scopes, ProxyForScope scope) {
return scopes[scope].parent;
}
void CheckLabelDoConstraints(const SourceStmtList &dos,
const SourceStmtList &branches, const TargetStmtMap &labels,
const std::vector<ScopeInfo> &scopes, SemanticsContext &context) {
IndexList loopBodies;
for (const auto &stmt : dos) {
const auto &label{stmt.parserLabel};
const auto &scope{stmt.proxyForScope};
const auto &position{stmt.parserCharBlock};
auto doTarget{GetLabel(labels, label)};
if (!HasScope(doTarget.proxyForScope)) {
// C1133
context.Say(
position, "Label '%u' cannot be found"_err_en_US, SayLabel(label));
} else if (doTarget.parserCharBlock.begin() < position.begin()) {
// R1119
context.Say(position,
"Label '%u' doesn't lexically follow DO stmt"_err_en_US,
SayLabel(label));
} else if ((InInclusiveScope(scopes, scope, doTarget.proxyForScope) &&
doTarget.labeledStmtClassificationSet.test(
TargetStatementEnum::CompatibleDo)) ||
(doTarget.isExecutableConstructEndStmt &&
ParentScope(scopes, doTarget.proxyForScope) == scope)) {
if (context.ShouldWarn(
common::LanguageFeature::OldLabelDoEndStatements)) {
context
.Say(position,
"A DO loop should terminate with an END DO or CONTINUE"_port_en_US)
.Attach(doTarget.parserCharBlock,
"DO loop currently ends at statement:"_en_US)
.set_languageFeature(
common::LanguageFeature::OldLabelDoEndStatements);
}
} else if (!InInclusiveScope(scopes, scope, doTarget.proxyForScope)) {
context.Say(position, "Label '%u' is not in DO loop scope"_err_en_US,
SayLabel(label));
} else if (!doTarget.labeledStmtClassificationSet.test(
TargetStatementEnum::Do)) {
context.Say(doTarget.parserCharBlock,
"A DO loop should terminate with an END DO or CONTINUE"_err_en_US);
} else {
loopBodies.emplace_back(SkipLabel(position), doTarget.parserCharBlock);
}
}
CheckBranchesIntoDoBody(branches, labels, loopBodies, context);
CheckDoNesting(loopBodies, context);
}
// 6.2.5
void CheckScopeConstraints(const SourceStmtList &stmts,
const TargetStmtMap &labels, const std::vector<ScopeInfo> &scopes,
SemanticsContext &context) {
for (const auto &stmt : stmts) {
const auto &label{stmt.parserLabel};
const auto &scope{stmt.proxyForScope};
const auto &position{stmt.parserCharBlock};
auto target{GetLabel(labels, label)};
if (!HasScope(target.proxyForScope)) {
context.Say(
position, "Label '%u' was not found"_err_en_US, SayLabel(label));
} else if (!InInclusiveScope(scopes, scope, target.proxyForScope)) {
// Clause 11.1.2.1 prohibits transfer of control to the interior of a
// block from outside the block, but this does not apply to formats.
// C1038 and C1034 forbid statements in FORALL and WHERE constructs
// (resp.) from being branch targets.
if (target.labeledStmtClassificationSet.test(
TargetStatementEnum::Format)) {
continue;
}
bool isFatal{false};
ProxyForScope fromScope{scope};
for (ProxyForScope toScope{target.proxyForScope}; HasScope(toScope);
toScope = scopes[toScope].parent) {
while (scopes[fromScope].depth > scopes[toScope].depth) {
fromScope = scopes[fromScope].parent;
}
if (toScope == fromScope) {
break;
}
if (scopes[toScope].isExteriorGotoFatal) {
isFatal = true;
break;
}
}
if (isFatal) {
context.Say(position,
"Label '%u' is in a construct that prevents its use as a branch target here"_err_en_US,
SayLabel(label));
} else if (context.ShouldWarn(
common::LanguageFeature::BranchIntoConstruct)) {
context
.Say(position,
"Label '%u' is in a construct that should not be used as a branch target here"_warn_en_US,
SayLabel(label))
.set_languageFeature(common::LanguageFeature::BranchIntoConstruct);
}
}
}
}
void CheckBranchTargetConstraints(const SourceStmtList &stmts,
const TargetStmtMap &labels, SemanticsContext &context) {
for (const auto &stmt : stmts) {
const auto &label{stmt.parserLabel};
auto branchTarget{GetLabel(labels, label)};
if (HasScope(branchTarget.proxyForScope)) {
if (!branchTarget.labeledStmtClassificationSet.test(
TargetStatementEnum::Branch) &&
!branchTarget.labeledStmtClassificationSet.test(
TargetStatementEnum::CompatibleBranch)) { // error
context
.Say(branchTarget.parserCharBlock,
"Label '%u' is not a branch target"_err_en_US, SayLabel(label))
.Attach(stmt.parserCharBlock, "Control flow use of '%u'"_en_US,
SayLabel(label));
} else if (!branchTarget.labeledStmtClassificationSet.test(
TargetStatementEnum::Branch) &&
context.ShouldWarn(common::LanguageFeature::BadBranchTarget)) {
context
.Say(branchTarget.parserCharBlock,
"Label '%u' is not a branch target"_warn_en_US, SayLabel(label))
.Attach(stmt.parserCharBlock, "Control flow use of '%u'"_en_US,
SayLabel(label))
.set_languageFeature(common::LanguageFeature::BadBranchTarget);
}
}
}
}
void CheckBranchConstraints(const SourceStmtList &branches,
const TargetStmtMap &labels, const std::vector<ScopeInfo> &scopes,
SemanticsContext &context) {
CheckScopeConstraints(branches, labels, scopes, context);
CheckBranchTargetConstraints(branches, labels, context);
}
void CheckDataXferTargetConstraints(const SourceStmtList &stmts,
const TargetStmtMap &labels, SemanticsContext &context) {
for (const auto &stmt : stmts) {
const auto &label{stmt.parserLabel};
auto ioTarget{GetLabel(labels, label)};
if (HasScope(ioTarget.proxyForScope)) {
if (!ioTarget.labeledStmtClassificationSet.test(
TargetStatementEnum::Format)) {
context
.Say(ioTarget.parserCharBlock, "'%u' not a FORMAT"_err_en_US,
SayLabel(label))
.Attach(stmt.parserCharBlock, "data transfer use of '%u'"_en_US,
SayLabel(label));
}
}
}
}
void CheckDataTransferConstraints(const SourceStmtList &dataTransfers,
const TargetStmtMap &labels, const std::vector<ScopeInfo> &scopes,
SemanticsContext &context) {
CheckScopeConstraints(dataTransfers, labels, scopes, context);
CheckDataXferTargetConstraints(dataTransfers, labels, context);
}
void CheckAssignTargetConstraints(const SourceStmtList &stmts,
const TargetStmtMap &labels, SemanticsContext &context) {
for (const auto &stmt : stmts) {
const auto &label{stmt.parserLabel};
auto target{GetLabel(labels, label)};
if (HasScope(target.proxyForScope) &&
!target.labeledStmtClassificationSet.test(
TargetStatementEnum::Branch) &&
!target.labeledStmtClassificationSet.test(
TargetStatementEnum::Format)) {
parser::Message *msg{nullptr};
if (!target.labeledStmtClassificationSet.test(
TargetStatementEnum::CompatibleBranch)) {
msg = &context.Say(target.parserCharBlock,
"Label '%u' is not a branch target or FORMAT"_err_en_US,
SayLabel(label));
} else if (context.ShouldWarn(common::LanguageFeature::BadBranchTarget)) {
msg =
&context
.Say(target.parserCharBlock,
"Label '%u' is not a branch target or FORMAT"_warn_en_US,
SayLabel(label))
.set_languageFeature(common::LanguageFeature::BadBranchTarget);
}
if (msg) {
msg->Attach(stmt.parserCharBlock, "ASSIGN statement use of '%u'"_en_US,
SayLabel(label));
}
}
}
}
void CheckAssignConstraints(const SourceStmtList &assigns,
const TargetStmtMap &labels, const std::vector<ScopeInfo> &scopes,
SemanticsContext &context) {
CheckScopeConstraints(assigns, labels, scopes, context);
CheckAssignTargetConstraints(assigns, labels, context);
}
bool CheckConstraints(ParseTreeAnalyzer &&parseTreeAnalysis) {
auto &context{parseTreeAnalysis.ErrorHandler()};
for (const auto &programUnit : parseTreeAnalysis.ProgramUnits()) {
const auto &dos{programUnit.doStmtSources};
const auto &branches{programUnit.otherStmtSources};
const auto &labels{programUnit.targetStmts};
const auto &scopes{programUnit.scopeModel};
CheckLabelDoConstraints(dos, branches, labels, scopes, context);
CheckBranchConstraints(branches, labels, scopes, context);
const auto &dataTransfers{programUnit.formatStmtSources};
CheckDataTransferConstraints(dataTransfers, labels, scopes, context);
const auto &assigns{programUnit.assignStmtSources};
CheckAssignConstraints(assigns, labels, scopes, context);
}
return !context.AnyFatalError();
}
bool ValidateLabels(SemanticsContext &context, const parser::Program &program) {
return CheckConstraints(LabelAnalysis(context, program));
}
} // namespace Fortran::semantics
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