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llvm-project/flang/lib/Semantics/data-to-inits.cpp

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//===-- lib/Semantics/data-to-inits.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
//
//===----------------------------------------------------------------------===//
// DATA statement object/value checking and conversion to static
// initializers
// - Applies specific checks to each scalar element initialization with a
// constant value or pointer target with class DataInitializationCompiler;
// - Collects the elemental initializations for each symbol and converts them
// into a single init() expression with member function
// DataChecker::ConstructInitializer().
#include "data-to-inits.h"
#include "pointer-assignment.h"
#include "flang/Evaluate/fold-designator.h"
#include "flang/Semantics/tools.h"
namespace Fortran::semantics {
// Steps through a list of values in a DATA statement set; implements
// repetition.
class ValueListIterator {
public:
explicit ValueListIterator(const parser::DataStmtSet &set)
: end_{std::get<std::list<parser::DataStmtValue>>(set.t).end()},
at_{std::get<std::list<parser::DataStmtValue>>(set.t).begin()} {
SetRepetitionCount();
}
bool hasFatalError() const { return hasFatalError_; }
bool IsAtEnd() const { return at_ == end_; }
const SomeExpr *operator*() const { return GetExpr(GetConstant()); }
parser::CharBlock LocateSource() const { return GetConstant().source; }
ValueListIterator &operator++() {
if (repetitionsRemaining_ > 0) {
--repetitionsRemaining_;
} else if (at_ != end_) {
++at_;
SetRepetitionCount();
}
return *this;
}
private:
using listIterator = std::list<parser::DataStmtValue>::const_iterator;
void SetRepetitionCount();
const parser::DataStmtConstant &GetConstant() const {
return std::get<parser::DataStmtConstant>(at_->t);
}
listIterator end_;
listIterator at_;
ConstantSubscript repetitionsRemaining_{0};
bool hasFatalError_{false};
};
void ValueListIterator::SetRepetitionCount() {
for (repetitionsRemaining_ = 1; at_ != end_; ++at_) {
if (at_->repetitions < 0) {
hasFatalError_ = true;
}
if (at_->repetitions > 0) {
repetitionsRemaining_ = at_->repetitions - 1;
return;
}
}
repetitionsRemaining_ = 0;
}
// Collects all of the elemental initializations from DATA statements
// into a single image for each symbol that appears in any DATA.
// Expands the implied DO loops and array references.
// Applies checks that validate each distinct elemental initialization
// of the variables in a data-stmt-set, as well as those that apply
// to the corresponding values being use to initialize each element.
class DataInitializationCompiler {
public:
DataInitializationCompiler(DataInitializations &inits,
evaluate::ExpressionAnalyzer &a, const parser::DataStmtSet &set)
: inits_{inits}, exprAnalyzer_{a}, values_{set} {}
const DataInitializations &inits() const { return inits_; }
bool HasSurplusValues() const { return !values_.IsAtEnd(); }
bool Scan(const parser::DataStmtObject &);
private:
bool Scan(const parser::Variable &);
bool Scan(const parser::Designator &);
bool Scan(const parser::DataImpliedDo &);
bool Scan(const parser::DataIDoObject &);
// Initializes all elements of a designator, which can be an array or section.
bool InitDesignator(const SomeExpr &);
// Initializes a single object.
bool InitElement(const evaluate::OffsetSymbol &, const SomeExpr &designator);
// If the returned flag is true, emit a warning about CHARACTER misusage.
std::optional<std::pair<SomeExpr, bool>> ConvertElement(
const SomeExpr &, const evaluate::DynamicType &);
DataInitializations &inits_;
evaluate::ExpressionAnalyzer &exprAnalyzer_;
ValueListIterator values_;
};
bool DataInitializationCompiler::Scan(const parser::DataStmtObject &object) {
return std::visit(
common::visitors{
[&](const common::Indirection<parser::Variable> &var) {
return Scan(var.value());
},
[&](const parser::DataImpliedDo &ido) { return Scan(ido); },
},
object.u);
}
bool DataInitializationCompiler::Scan(const parser::Variable &var) {
if (const auto *expr{GetExpr(var)}) {
exprAnalyzer_.GetFoldingContext().messages().SetLocation(var.GetSource());
if (InitDesignator(*expr)) {
return true;
}
}
return false;
}
bool DataInitializationCompiler::Scan(const parser::Designator &designator) {
if (auto expr{exprAnalyzer_.Analyze(designator)}) {
exprAnalyzer_.GetFoldingContext().messages().SetLocation(
parser::FindSourceLocation(designator));
if (InitDesignator(*expr)) {
return true;
}
}
return false;
}
bool DataInitializationCompiler::Scan(const parser::DataImpliedDo &ido) {
const auto &bounds{std::get<parser::DataImpliedDo::Bounds>(ido.t)};
auto name{bounds.name.thing.thing};
const auto *lowerExpr{GetExpr(bounds.lower.thing.thing)};
const auto *upperExpr{GetExpr(bounds.upper.thing.thing)};
const auto *stepExpr{
bounds.step ? GetExpr(bounds.step->thing.thing) : nullptr};
if (lowerExpr && upperExpr) {
auto lower{ToInt64(*lowerExpr)};
auto upper{ToInt64(*upperExpr)};
auto step{stepExpr ? ToInt64(*stepExpr) : std::nullopt};
auto stepVal{step.value_or(1)};
if (stepVal == 0) {
exprAnalyzer_.Say(name.source,
"DATA statement implied DO loop has a step value of zero"_err_en_US);
} else if (lower && upper) {
int kind{evaluate::ResultType<evaluate::ImpliedDoIndex>::kind};
if (const auto dynamicType{evaluate::DynamicType::From(*name.symbol)}) {
if (dynamicType->category() == TypeCategory::Integer) {
kind = dynamicType->kind();
}
}
if (exprAnalyzer_.AddImpliedDo(name.source, kind)) {
auto &value{exprAnalyzer_.GetFoldingContext().StartImpliedDo(
name.source, *lower)};
bool result{true};
for (auto n{(*upper - value + stepVal) / stepVal}; n > 0;
--n, value += stepVal) {
for (const auto &object :
std::get<std::list<parser::DataIDoObject>>(ido.t)) {
if (!Scan(object)) {
result = false;
break;
}
}
}
exprAnalyzer_.GetFoldingContext().EndImpliedDo(name.source);
exprAnalyzer_.RemoveImpliedDo(name.source);
return result;
}
}
}
return false;
}
bool DataInitializationCompiler::Scan(const parser::DataIDoObject &object) {
return std::visit(
common::visitors{
[&](const parser::Scalar<common::Indirection<parser::Designator>>
&var) { return Scan(var.thing.value()); },
[&](const common::Indirection<parser::DataImpliedDo> &ido) {
return Scan(ido.value());
},
},
object.u);
}
bool DataInitializationCompiler::InitDesignator(const SomeExpr &designator) {
evaluate::FoldingContext &context{exprAnalyzer_.GetFoldingContext()};
evaluate::DesignatorFolder folder{context};
while (auto offsetSymbol{folder.FoldDesignator(designator)}) {
if (folder.isOutOfRange()) {
if (auto bad{evaluate::OffsetToDesignator(context, *offsetSymbol)}) {
exprAnalyzer_.context().Say(
"DATA statement designator '%s' is out of range"_err_en_US,
bad->AsFortran());
} else {
exprAnalyzer_.context().Say(
"DATA statement designator '%s' is out of range"_err_en_US,
designator.AsFortran());
}
return false;
} else if (!InitElement(*offsetSymbol, designator)) {
return false;
} else {
++values_;
}
}
return folder.isEmpty();
}
std::optional<std::pair<SomeExpr, bool>>
DataInitializationCompiler::ConvertElement(
const SomeExpr &expr, const evaluate::DynamicType &type) {
if (auto converted{evaluate::ConvertToType(type, SomeExpr{expr})}) {
return {std::make_pair(std::move(*converted), false)};
}
if (std::optional<std::string> chValue{evaluate::GetScalarConstantValue<
evaluate::Type<TypeCategory::Character, 1>>(expr)}) {
// Allow DATA initialization with Hollerith and kind=1 CHARACTER like
// (most) other Fortran compilers do. Pad on the right with spaces
// when short, truncate the right if long.
// TODO: big-endian targets
std::size_t bytes{static_cast<std::size_t>(evaluate::ToInt64(
type.MeasureSizeInBytes(&exprAnalyzer_.GetFoldingContext()))
.value())};
evaluate::BOZLiteralConstant bits{0};
for (std::size_t j{0}; j < bytes; ++j) {
char ch{j >= chValue->size() ? ' ' : chValue->at(j)};
evaluate::BOZLiteralConstant chBOZ{static_cast<unsigned char>(ch)};
bits = bits.IOR(chBOZ.SHIFTL(8 * j));
}
if (auto converted{evaluate::ConvertToType(type, SomeExpr{bits})}) {
return {std::make_pair(std::move(*converted), true)};
}
}
return std::nullopt;
}
bool DataInitializationCompiler::InitElement(
const evaluate::OffsetSymbol &offsetSymbol, const SomeExpr &designator) {
const Symbol &symbol{offsetSymbol.symbol()};
const Symbol *lastSymbol{GetLastSymbol(designator)};
bool isPointer{lastSymbol && IsPointer(*lastSymbol)};
bool isProcPointer{lastSymbol && IsProcedurePointer(*lastSymbol)};
evaluate::FoldingContext &context{exprAnalyzer_.GetFoldingContext()};
auto restorer{context.messages().SetLocation(values_.LocateSource())};
const auto DescribeElement{[&]() {
if (auto badDesignator{
evaluate::OffsetToDesignator(context, offsetSymbol)}) {
return badDesignator->AsFortran();
} else {
// Error recovery
std::string buf;
llvm::raw_string_ostream ss{buf};
ss << offsetSymbol.symbol().name() << " offset " << offsetSymbol.offset()
<< " bytes for " << offsetSymbol.size() << " bytes";
return ss.str();
}
}};
const auto GetImage{[&]() -> evaluate::InitialImage & {
auto &symbolInit{inits_.emplace(&symbol, symbol.size()).first->second};
symbolInit.inits.emplace_back(offsetSymbol.offset(), offsetSymbol.size());
return symbolInit.image;
}};
const auto OutOfRangeError{[&]() {
evaluate::AttachDeclaration(
exprAnalyzer_.context().Say(
"DATA statement designator '%s' is out of range for its variable '%s'"_err_en_US,
DescribeElement(), symbol.name()),
symbol);
}};
if (values_.hasFatalError()) {
return false;
} else if (values_.IsAtEnd()) {
exprAnalyzer_.context().Say(
"DATA statement set has no value for '%s'"_err_en_US,
DescribeElement());
return false;
} else if (static_cast<std::size_t>(
offsetSymbol.offset() + offsetSymbol.size()) > symbol.size()) {
OutOfRangeError();
return false;
}
const SomeExpr *expr{*values_};
if (!expr) {
CHECK(exprAnalyzer_.context().AnyFatalError());
} else if (isPointer) {
if (static_cast<std::size_t>(offsetSymbol.offset() + offsetSymbol.size()) >
symbol.size()) {
OutOfRangeError();
} else if (evaluate::IsNullPointer(*expr)) {
// nothing to do; rely on zero initialization
return true;
} else if (isProcPointer) {
if (evaluate::IsProcedure(*expr)) {
if (CheckPointerAssignment(context, designator, *expr)) {
GetImage().AddPointer(offsetSymbol.offset(), *expr);
return true;
}
} else {
exprAnalyzer_.Say(
"Data object '%s' may not be used to initialize '%s', which is a procedure pointer"_err_en_US,
expr->AsFortran(), DescribeElement());
}
} else if (evaluate::IsProcedure(*expr)) {
exprAnalyzer_.Say(
"Procedure '%s' may not be used to initialize '%s', which is not a procedure pointer"_err_en_US,
expr->AsFortran(), DescribeElement());
} else if (CheckInitialTarget(context, designator, *expr)) {
GetImage().AddPointer(offsetSymbol.offset(), *expr);
return true;
}
} else if (evaluate::IsNullPointer(*expr)) {
exprAnalyzer_.Say("Initializer for '%s' must not be a pointer"_err_en_US,
DescribeElement());
} else if (evaluate::IsProcedure(*expr)) {
exprAnalyzer_.Say("Initializer for '%s' must not be a procedure"_err_en_US,
DescribeElement());
} else if (auto designatorType{designator.GetType()}) {
if (auto converted{ConvertElement(*expr, *designatorType)}) {
// value non-pointer initialization
if (std::holds_alternative<evaluate::BOZLiteralConstant>(expr->u) &&
designatorType->category() != TypeCategory::Integer) { // 8.6.7(11)
exprAnalyzer_.Say(
"BOZ literal should appear in a DATA statement only as a value for an integer object, but '%s' is '%s'"_en_US,
DescribeElement(), designatorType->AsFortran());
} else if (converted->second) {
exprAnalyzer_.context().Say(
"DATA statement value initializes '%s' of type '%s' with CHARACTER"_en_US,
DescribeElement(), designatorType->AsFortran());
}
auto folded{evaluate::Fold(context, std::move(converted->first))};
switch (
GetImage().Add(offsetSymbol.offset(), offsetSymbol.size(), folded)) {
case evaluate::InitialImage::Ok:
return true;
case evaluate::InitialImage::NotAConstant:
exprAnalyzer_.Say(
"DATA statement value '%s' for '%s' is not a constant"_err_en_US,
folded.AsFortran(), DescribeElement());
break;
case evaluate::InitialImage::OutOfRange:
OutOfRangeError();
break;
default:
CHECK(exprAnalyzer_.context().AnyFatalError());
break;
}
} else {
exprAnalyzer_.context().Say(
"DATA statement value could not be converted to the type '%s' of the object '%s'"_err_en_US,
designatorType->AsFortran(), DescribeElement());
}
} else {
CHECK(exprAnalyzer_.context().AnyFatalError());
}
return false;
}
void AccumulateDataInitializations(DataInitializations &inits,
evaluate::ExpressionAnalyzer &exprAnalyzer,
const parser::DataStmtSet &set) {
DataInitializationCompiler scanner{inits, exprAnalyzer, set};
for (const auto &object :
std::get<std::list<parser::DataStmtObject>>(set.t)) {
if (!scanner.Scan(object)) {
return;
}
}
if (scanner.HasSurplusValues()) {
exprAnalyzer.context().Say(
"DATA statement set has more values than objects"_err_en_US);
}
}
static bool CombineSomeEquivalencedInits(
DataInitializations &inits, evaluate::ExpressionAnalyzer &exprAnalyzer) {
auto end{inits.end()};
for (auto iter{inits.begin()}; iter != end; ++iter) {
const Symbol &symbol{*iter->first};
Scope &scope{const_cast<Scope &>(symbol.owner())};
if (scope.equivalenceSets().empty()) {
continue; // no problem to solve here
}
const auto *commonBlock{FindCommonBlockContaining(symbol)};
// Sweep following DATA initializations in search of overlapping
// objects, accumulating into a vector; iterate to a fixed point.
std::vector<const Symbol *> conflicts;
auto minStart{symbol.offset()};
auto maxEnd{symbol.offset() + symbol.size()};
std::size_t minElementBytes{1};
while (true) {
auto prevCount{conflicts.size()};
conflicts.clear();
for (auto scan{iter}; ++scan != end;) {
const Symbol &other{*scan->first};
const Scope &otherScope{other.owner()};
if (&otherScope == &scope &&
FindCommonBlockContaining(other) == commonBlock &&
maxEnd > other.offset() &&
other.offset() + other.size() > minStart) {
// "other" conflicts with "symbol" or another conflict
conflicts.push_back(&other);
minStart = std::min(minStart, other.offset());
maxEnd = std::max(maxEnd, other.offset() + other.size());
}
}
if (conflicts.size() == prevCount) {
break;
}
}
if (conflicts.empty()) {
continue;
}
// Compute the minimum common granularity
if (auto dyType{evaluate::DynamicType::From(symbol)}) {
minElementBytes = evaluate::ToInt64(
dyType->MeasureSizeInBytes(&exprAnalyzer.GetFoldingContext()))
.value_or(1);
}
for (const Symbol *s : conflicts) {
if (auto dyType{evaluate::DynamicType::From(*s)}) {
minElementBytes = std::min(minElementBytes,
static_cast<std::size_t>(evaluate::ToInt64(
dyType->MeasureSizeInBytes(&exprAnalyzer.GetFoldingContext()))
.value_or(1)));
} else {
minElementBytes = 1;
}
}
CHECK(minElementBytes > 0);
CHECK((minElementBytes & (minElementBytes - 1)) == 0);
auto bytes{static_cast<common::ConstantSubscript>(maxEnd - minStart)};
CHECK(bytes % minElementBytes == 0);
const DeclTypeSpec &typeSpec{scope.MakeNumericType(
TypeCategory::Integer, KindExpr{minElementBytes})};
// Combine "symbol" and "conflicts[]" into a compiler array temp
// that overlaps all of them, and merge their initial values into
// the temp's initializer.
SourceName name{exprAnalyzer.context().GetTempName(scope)};
auto emplaced{
scope.try_emplace(name, Attrs{Attr::SAVE}, ObjectEntityDetails{})};
CHECK(emplaced.second);
Symbol &combinedSymbol{*emplaced.first->second};
auto &details{combinedSymbol.get<ObjectEntityDetails>()};
combinedSymbol.set_offset(minStart);
combinedSymbol.set_size(bytes);
details.set_type(typeSpec);
ArraySpec arraySpec;
arraySpec.emplace_back(ShapeSpec::MakeExplicit(Bound{
bytes / static_cast<common::ConstantSubscript>(minElementBytes)}));
details.set_shape(arraySpec);
if (commonBlock) {
details.set_commonBlock(*commonBlock);
}
// Merge these EQUIVALENCE'd DATA initializations, and remove the
// original initializations from the map.
auto combinedInit{
inits.emplace(&combinedSymbol, static_cast<std::size_t>(bytes))};
evaluate::InitialImage &combined{combinedInit.first->second.image};
combined.Incorporate(symbol.offset() - minStart, iter->second.image);
inits.erase(iter);
for (const Symbol *s : conflicts) {
auto sIter{inits.find(s)};
CHECK(sIter != inits.end());
combined.Incorporate(s->offset() - minStart, sIter->second.image);
inits.erase(sIter);
}
return true; // got one
}
return false; // no remaining EQUIVALENCE'd DATA initializations
}
// Converts the initialization image for all the DATA statement appearances of
// a single symbol into an init() expression in the symbol table entry.
void ConstructInitializer(const Symbol &symbol,
SymbolDataInitialization &initialization,
evaluate::ExpressionAnalyzer &exprAnalyzer) {
auto &context{exprAnalyzer.GetFoldingContext()};
initialization.inits.sort();
ConstantSubscript next{0};
for (const auto &init : initialization.inits) {
if (init.start() < next) {
auto badDesignator{evaluate::OffsetToDesignator(
context, symbol, init.start(), init.size())};
CHECK(badDesignator);
exprAnalyzer.Say(symbol.name(),
"DATA statement initializations affect '%s' more than once"_err_en_US,
badDesignator->AsFortran());
}
next = init.start() + init.size();
CHECK(next <= static_cast<ConstantSubscript>(initialization.image.size()));
}
if (const auto *proc{symbol.detailsIf<ProcEntityDetails>()}) {
CHECK(IsProcedurePointer(symbol));
const auto &procDesignator{initialization.image.AsConstantProcPointer()};
CHECK(!procDesignator.GetComponent());
auto &mutableProc{const_cast<ProcEntityDetails &>(*proc)};
mutableProc.set_init(DEREF(procDesignator.GetSymbol()));
} else if (const auto *object{symbol.detailsIf<ObjectEntityDetails>()}) {
if (auto symbolType{evaluate::DynamicType::From(symbol)}) {
auto &mutableObject{const_cast<ObjectEntityDetails &>(*object)};
if (IsPointer(symbol)) {
mutableObject.set_init(
initialization.image.AsConstantDataPointer(*symbolType));
} else {
if (auto extents{evaluate::GetConstantExtents(context, symbol)}) {
mutableObject.set_init(
initialization.image.AsConstant(context, *symbolType, *extents));
} else {
exprAnalyzer.Say(symbol.name(),
"internal: unknown shape for '%s' while constructing initializer from DATA"_err_en_US,
symbol.name());
return;
}
}
} else {
exprAnalyzer.Say(symbol.name(),
"internal: no type for '%s' while constructing initializer from DATA"_err_en_US,
symbol.name());
return;
}
if (!object->init()) {
exprAnalyzer.Say(symbol.name(),
"internal: could not construct an initializer from DATA statements for '%s'"_err_en_US,
symbol.name());
}
} else {
CHECK(exprAnalyzer.context().AnyFatalError());
}
}
void ConvertToInitializers(
DataInitializations &inits, evaluate::ExpressionAnalyzer &exprAnalyzer) {
while (CombineSomeEquivalencedInits(inits, exprAnalyzer)) {
}
for (auto &[symbolPtr, initialization] : inits) {
ConstructInitializer(*symbolPtr, initialization, exprAnalyzer);
}
}
} // namespace Fortran::semantics
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