llvm-project

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//===-- lib/Semantics/check-return.cpp ------------------------------------===//
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//
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// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
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// See https://llvm.org/LICENSE.txt for license information.
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// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
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//
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//===----------------------------------------------------------------------===//
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#include "check-return.h"
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#include "flang/Common/Fortran-features.h"
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#include "flang/Parser/message.h"
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#include "flang/Parser/parse-tree.h"
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#include "flang/Semantics/semantics.h"
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#include "flang/Semantics/tools.h"
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namespace Fortran::semantics {
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static const Scope *FindContainingSubprogram(const Scope &start) {
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  const Scope &scope{GetProgramUnitContaining(start)};
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  return scope.kind() == Scope::Kind::MainProgram ||
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          scope.kind() == Scope::Kind::Subprogram
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      ? &scope
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      : nullptr;
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}
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void ReturnStmtChecker::Leave(const parser::ReturnStmt &returnStmt) {
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  // R1542 Expression analysis validates the scalar-int-expr
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  // C1574 The return-stmt shall be in the inclusive scope of a function or
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  // subroutine subprogram.
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  // C1575 The scalar-int-expr is allowed only in the inclusive scope of a
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  // subroutine subprogram.
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  const auto &scope{context_.FindScope(context_.location().value())};
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  if (const auto *subprogramScope{FindContainingSubprogram(scope)}) {
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    if (returnStmt.v &&
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        (subprogramScope->kind() == Scope::Kind::MainProgram ||
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            IsFunction(*subprogramScope->GetSymbol()))) {
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      context_.Say(
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          "RETURN with expression is only allowed in SUBROUTINE subprogram"_err_en_US);
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    } else if (subprogramScope->kind() == Scope::Kind::MainProgram &&
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        context_.ShouldWarn(common::LanguageFeature::ProgramReturn)) {
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      context_.Say("RETURN should not appear in a main program"_port_en_US);
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    }
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  }
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}
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} // namespace Fortran::semantics
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