llvm/flang/lib/semantics/semantics.cc

// Copyright (c) 2018-2019, NVIDIA CORPORATION.  All rights reserved.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//     http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

#include "semantics.h"
#include "assignment.h"
#include "canonicalize-do.h"
#include "check-allocate.h"
#include "check-arithmeticif.h"
#include "check-coarray.h"
#include "check-deallocate.h"
#include "check-do-stmt.h"
#include "check-if-stmt.h"
#include "check-io.h"
#include "check-nullify.h"
#include "check-return.h"
#include "check-stop.h"
#include "expression.h"
#include "mod-file.h"
#include "resolve-labels.h"
#include "resolve-names.h"
#include "rewrite-parse-tree.h"
#include "scope.h"
#include "symbol.h"
#include "../common/default-kinds.h"
#include "../parser/parse-tree-visitor.h"

namespace Fortran::semantics {

static void DoDumpSymbols(std::ostream &, const Scope &, int indent = 0);
static void PutIndent(std::ostream &, int indent);

// A parse tree visitor that calls Enter/Leave functions from each checker
// class C supplied as template parameters. Enter is called before the node's
// children are visited, Leave is called after. No two checkers may have the
// same Enter or Leave function. Each checker must be constructible from
// SemanticsContext and have BaseChecker as a virtual base class.
template<typename... C> class SemanticsVisitor : public virtual C... {
public:
  using C::Enter...;
  using C::Leave...;
  using BaseChecker::Enter;
  using BaseChecker::Leave;
  SemanticsVisitor(SemanticsContext &context)
    : C{context}..., context_{context} {}

  template<typename N> bool Pre(const N &node) {
    Enter(node);
    return true;
  }
  template<typename N> void Post(const N &node) { Leave(node); }

  template<typename T> bool Pre(const parser::Statement<T> &node) {
    context_.set_location(&node.source);
    Enter(node);
    return true;
  }
  template<typename T> void Post(const parser::Statement<T> &node) {
    Leave(node);
    context_.set_location(nullptr);
  }

  bool Walk(const parser::Program &program) {
    parser::Walk(program, *this);
    return !context_.AnyFatalError();
  }

private:
  SemanticsContext &context_;
};

using StatementSemanticsPass1 = ExprChecker;
using StatementSemanticsPass2 = SemanticsVisitor<AllocateChecker,
    ArithmeticIfStmtChecker, AssignmentChecker, CoarrayChecker,
    DeallocateChecker, DoStmtChecker, IfStmtChecker, IoChecker,
    NullifyChecker, ReturnStmtChecker, StopChecker>;

static bool PerformStatementSemantics(
    SemanticsContext &context, parser::Program &program) {
  ResolveNames(context, program);
  RewriteParseTree(context, program);
  StatementSemanticsPass1{context}.Walk(program);
  return StatementSemanticsPass2{context}.Walk(program);
}

SemanticsContext::SemanticsContext(
    const common::IntrinsicTypeDefaultKinds &defaultKinds,
    const parser::LanguageFeatureControl &languageFeatures,
    parser::AllSources &allSources)
  : defaultKinds_{defaultKinds}, languageFeatures_{languageFeatures},
    allSources_{allSources},
    intrinsics_{evaluate::IntrinsicProcTable::Configure(defaultKinds)},
    foldingContext_{evaluate::FoldingContext{
        parser::ContextualMessages{parser::CharBlock{}, &messages_}}} {}

SemanticsContext::~SemanticsContext() {}

bool SemanticsContext::IsEnabled(parser::LanguageFeature feature) const {
  return languageFeatures_.IsEnabled(feature);
}

bool SemanticsContext::ShouldWarn(parser::LanguageFeature feature) const {
  return languageFeatures_.ShouldWarn(feature);
}

const DeclTypeSpec &SemanticsContext::MakeNumericType(
    TypeCategory category, int kind) {
  if (kind == 0) {
    kind = defaultKinds_.GetDefaultKind(category);
  }
  return globalScope_.MakeNumericType(category, KindExpr{kind});
}
const DeclTypeSpec &SemanticsContext::MakeLogicalType(int kind) {
  if (kind == 0) {
    kind = defaultKinds_.GetDefaultKind(TypeCategory::Logical);
  }
  return globalScope_.MakeLogicalType(KindExpr{kind});
}

bool SemanticsContext::AnyFatalError() const {
  return !messages_.empty() &&
      (warningsAreErrors_ || messages_.AnyFatalError());
}
bool SemanticsContext::HasError(const Symbol &symbol) {
  return CheckError(symbol.test(Symbol::Flag::Error));
}
bool SemanticsContext::HasError(const Symbol *symbol) {
  return CheckError(!symbol || HasError(*symbol));
}
bool SemanticsContext::HasError(const parser::Name &name) {
  return HasError(name.symbol);
}
void SemanticsContext::SetError(Symbol &symbol, bool value) {
  if (value) {
    CHECK(AnyFatalError());
    symbol.set(Symbol::Flag::Error);
  }
}
bool SemanticsContext::CheckError(bool error) {
  CHECK(!error || AnyFatalError());
  return error;
}

const Scope &SemanticsContext::FindScope(parser::CharBlock source) const {
  return const_cast<SemanticsContext *>(this)->FindScope(source);
}

Scope &SemanticsContext::FindScope(parser::CharBlock source) {
  if (auto *scope{globalScope_.FindScope(source)}) {
    return *scope;
  } else {
    common::die("invalid source location");
  }
}

bool Semantics::Perform() {
  return ValidateLabels(context_.messages(), program_) &&
      parser::CanonicalizeDo(program_) &&  // force line break
      PerformStatementSemantics(context_, program_) &&
      ModFileWriter{context_}.WriteAll();
}

void Semantics::EmitMessages(std::ostream &os) const {
  context_.messages().Emit(os, cooked_);
}

void Semantics::DumpSymbols(std::ostream &os) {
  DoDumpSymbols(os, context_.globalScope());
}

void DoDumpSymbols(std::ostream &os, const Scope &scope, int indent) {
  PutIndent(os, indent);
  os << Scope::EnumToString(scope.kind()) << " scope:";
  if (const auto *symbol{scope.symbol()}) {
    os << ' ' << symbol->name().ToString();
  }
  os << '\n';
  ++indent;
  for (const auto &pair : scope) {
    const auto &symbol{*pair.second};
    PutIndent(os, indent);
    os << symbol << '\n';
    if (const auto *details{symbol.detailsIf<GenericDetails>()}) {
      if (const auto &type{details->derivedType()}) {
        PutIndent(os, indent);
        os << *type << '\n';
      }
    }
  }
  for (const auto &pair : scope.commonBlocks()) {
    const auto &symbol{*pair.second};
    PutIndent(os, indent);
    os << symbol << '\n';
  }
  for (const auto &child : scope.children()) {
    DoDumpSymbols(os, child, indent);
  }
  --indent;
}

static void PutIndent(std::ostream &os, int indent) {
  for (int i = 0; i < indent; ++i) {
    os << "  ";
  }
}
}