//===-- lib/Semantics/check-data.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 semantic analysis.
// - Applies static semantic checks to the variables in each data-stmt-set with
// class DataVarChecker;
// - Invokes conversion of DATA statement values to static initializers
#include "check-data.h"
#include "data-to-inits.h"
#include "flang/Evaluate/traverse.h"
#include "flang/Parser/parse-tree.h"
#include "flang/Parser/tools.h"
#include "flang/Semantics/tools.h"
#include <algorithm>
#include <vector>
namespace Fortran::semantics {
// Ensures that references to an implied DO loop control variable are
// represented as such in the "body" of the implied DO loop.
void DataChecker::Enter(const parser::DataImpliedDo &x) {
auto name{std::get<parser::DataImpliedDo::Bounds>(x.t).name.thing.thing};
int kind{evaluate::ResultType<evaluate::ImpliedDoIndex>::kind};
if (const auto dynamicType{evaluate::DynamicType::From(*name.symbol)}) {
if (dynamicType->category() == TypeCategory::Integer) {
kind = dynamicType->kind();
}
}
exprAnalyzer_.AddImpliedDo(name.source, kind);
}
void DataChecker::Leave(const parser::DataImpliedDo &x) {
auto name{std::get<parser::DataImpliedDo::Bounds>(x.t).name.thing.thing};
exprAnalyzer_.RemoveImpliedDo(name.source);
}
// DataVarChecker applies static checks once to each variable that appears
// in a data-stmt-set. These checks are independent of the values that
// correspond to the variables.
class DataVarChecker : public evaluate::AllTraverse<DataVarChecker, true> {
public:
using Base = evaluate::AllTraverse<DataVarChecker, true>;
DataVarChecker(SemanticsContext &c, parser::CharBlock src)
: Base{*this}, context_{c}, source_{src} {}
using Base::operator();
bool HasComponentWithoutSubscripts() const {
return hasComponent_ && !hasSubscript_;
}
bool operator()(const Symbol &symbol) { // C876
// 8.6.7p(2) - precludes non-pointers of derived types with
// default component values
const Scope &scope{context_.FindScope(source_)};
bool isFirstSymbol{isFirstSymbol_};
isFirstSymbol_ = false;
// Ordered so that most egregious errors are first
if (const char *whyNot{IsProcedure(symbol) && !IsPointer(symbol)
? "Procedure"
: isFirstSymbol && IsHostAssociated(symbol, scope)
? "Host-associated object"
: isFirstSymbol && IsUseAssociated(symbol, scope)
? "USE-associated object"
: IsDummy(symbol) ? "Dummy argument"
: IsFunctionResult(symbol) ? "Function result"
: IsAutomatic(symbol) ? "Automatic variable"
: IsAllocatable(symbol) ? "Allocatable"
: IsInitialized(symbol, true /*ignore DATA*/,
true /*ignore allocatable components*/,
true /*ignore uninitialized pointer components*/)
? "Default-initialized"
: symbol.has<AssocEntityDetails>() ? "Construct association"
: isFirstSymbol && IsPointer(symbol) &&
(hasComponent_ || hasSubscript_)
? "Target of pointer"
: nullptr}) {
context_.Say(source_,
"%s '%s' must not be initialized in a DATA statement"_err_en_US,
whyNot, symbol.name());
return false;
}
if (IsProcedurePointer(symbol)) {
if (!context_.IsEnabled(common::LanguageFeature::DataStmtExtensions)) {
context_.Say(source_,
"Procedure pointer '%s' may not appear in a DATA statement"_err_en_US,
symbol.name());
return false;
} else if (context_.ShouldWarn(
common::LanguageFeature::DataStmtExtensions)) {
context_.Say(source_,
"Procedure pointer '%s' in a DATA statement is not standard"_port_en_US,
symbol.name());
}
}
if (IsInBlankCommon(symbol)) {
if (!context_.IsEnabled(common::LanguageFeature::DataStmtExtensions)) {
context_.Say(source_,
"Blank COMMON object '%s' may not appear in a DATA statement"_err_en_US,
symbol.name());
return false;
} else if (context_.ShouldWarn(
common::LanguageFeature::DataStmtExtensions)) {
context_.Say(source_,
"Blank COMMON object '%s' in a DATA statement is not standard"_port_en_US,
symbol.name());
}
}
return true;
}
bool operator()(const evaluate::Component &component) {
hasComponent_ = true;
const Symbol &lastSymbol{component.GetLastSymbol()};
if (isPointerAllowed_) {
if (IsPointer(lastSymbol) && hasSubscript_) { // C877
context_.Say(source_,
"Rightmost data object pointer '%s' must not be subscripted"_err_en_US,
lastSymbol.name().ToString());
return false;
}
auto restorer{common::ScopedSet(isPointerAllowed_, false)};
return (*this)(component.base()) && (*this)(lastSymbol);
} else if (IsPointer(lastSymbol)) { // C877
context_.Say(source_,
"Data object must not contain pointer '%s' as a non-rightmost part"_err_en_US,
lastSymbol.name().ToString());
return false;
} else {
return (*this)(component.base()) && (*this)(lastSymbol);
}
}
bool operator()(const evaluate::ArrayRef &arrayRef) {
hasSubscript_ = true;
return (*this)(arrayRef.base()) && (*this)(arrayRef.subscript());
}
bool operator()(const evaluate::Substring &substring) {
hasSubscript_ = true;
return (*this)(substring.parent()) && (*this)(substring.lower()) &&
(*this)(substring.upper());
}
bool operator()(const evaluate::CoarrayRef &) { // C874
context_.Say(
source_, "Data object must not be a coindexed variable"_err_en_US);
return false;
}
bool operator()(const evaluate::Subscript &subs) {
auto restorer1{common::ScopedSet(isPointerAllowed_, false)};
auto restorer2{common::ScopedSet(isFunctionAllowed_, true)};
return common::visit(
common::visitors{
[&](const evaluate::IndirectSubscriptIntegerExpr &expr) {
return CheckSubscriptExpr(expr);
},
[&](const evaluate::Triplet &triplet) {
return CheckSubscriptExpr(triplet.lower()) &&
CheckSubscriptExpr(triplet.upper()) &&
CheckSubscriptExpr(triplet.stride());
},
},
subs.u);
}
template <typename T>
bool operator()(const evaluate::FunctionRef<T> &) const { // C875
if (isFunctionAllowed_) {
// Must have been validated as a constant expression
return true;
} else {
context_.Say(source_,
"Data object variable must not be a function reference"_err_en_US);
return false;
}
}
private:
bool CheckSubscriptExpr(
const std::optional<evaluate::IndirectSubscriptIntegerExpr> &x) const {
return !x || CheckSubscriptExpr(*x);
}
bool CheckSubscriptExpr(
const evaluate::IndirectSubscriptIntegerExpr &expr) const {
return CheckSubscriptExpr(expr.value());
}
bool CheckSubscriptExpr(
const evaluate::Expr<evaluate::SubscriptInteger> &expr) const {
if (!evaluate::IsConstantExpr(expr)) { // C875,C881
context_.Say(
source_, "Data object must have constant subscripts"_err_en_US);
return false;
} else {
return true;
}
}
SemanticsContext &context_;
parser::CharBlock source_;
bool hasComponent_{false};
bool hasSubscript_{false};
bool isPointerAllowed_{true};
bool isFirstSymbol_{true};
bool isFunctionAllowed_{false};
};
static bool IsValidDataObject(const SomeExpr &expr) { // C878, C879
return !evaluate::IsConstantExpr(expr) &&
(evaluate::IsVariable(expr) || evaluate::IsProcedurePointer(expr));
}
void DataChecker::Leave(const parser::DataIDoObject &object) {
if (const auto *designator{
std::get_if<parser::Scalar<common::Indirection<parser::Designator>>>(
&object.u)}) {
if (MaybeExpr expr{exprAnalyzer_.Analyze(*designator)}) {
auto source{designator->thing.value().source};
DataVarChecker checker{exprAnalyzer_.context(), source};
if (checker(*expr)) {
if (checker.HasComponentWithoutSubscripts()) { // C880
exprAnalyzer_.context().Say(source,
"Data implied do structure component must be subscripted"_err_en_US);
} else if (!IsValidDataObject(*expr)) {
exprAnalyzer_.context().Say(
source, "Data implied do object must be a variable"_err_en_US);
} else {
return;
}
}
}
currentSetHasFatalErrors_ = true;
}
}
void DataChecker::Leave(const parser::DataStmtObject &dataObject) {
common::visit(
common::visitors{
[](const parser::DataImpliedDo &) { // has own Enter()/Leave()
},
[&](const auto &var) {
auto expr{exprAnalyzer_.Analyze(var)};
auto source{parser::FindSourceLocation(dataObject)};
if (!expr ||
!DataVarChecker{exprAnalyzer_.context(), source}(*expr)) {
currentSetHasFatalErrors_ = true;
} else if (!IsValidDataObject(*expr)) {
exprAnalyzer_.context().Say(
source, "Data statement object must be a variable"_err_en_US);
currentSetHasFatalErrors_ = true;
}
},
},
dataObject.u);
}
void DataChecker::Leave(const parser::DataStmtSet &set) {
if (!currentSetHasFatalErrors_) {
AccumulateDataInitializations(inits_, exprAnalyzer_, set);
}
currentSetHasFatalErrors_ = false;
}
// Handle legacy DATA-style initialization, e.g. REAL PI/3.14159/, for
// variables and components (esp. for DEC STRUCTUREs)
template <typename A> void DataChecker::LegacyDataInit(const A &decl) {
if (const auto &init{
std::get<std::optional<parser::Initialization>>(decl.t)}) {
const Symbol *name{std::get<parser::Name>(decl.t).symbol};
const auto *list{
std::get_if<std::list<common::Indirection<parser::DataStmtValue>>>(
&init->u)};
if (name && list) {
AccumulateDataInitializations(inits_, exprAnalyzer_, *name, *list);
}
}
}
void DataChecker::Leave(const parser::ComponentDecl &decl) {
LegacyDataInit(decl);
}
void DataChecker::Leave(const parser::EntityDecl &decl) {
LegacyDataInit(decl);
}
void DataChecker::CompileDataInitializationsIntoInitializers() {
ConvertToInitializers(inits_, exprAnalyzer_);
}
} // namespace Fortran::semantics
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