source: src/ControlStruct/FixLabels.cpp @ de31a1d

//
// Cforall Version 1.0.0 Copyright (C) 2015 University of Waterloo
//
// The contents of this file are covered under the licence agreement in the
// file "LICENCE" distributed with Cforall.
//
// FixLabels.cpp -- Normalizes labels and handles multi-level exit labels.
//
// Author           : Andrew Beach
// Created On       : Mon Nov  1 09:39:00 2021
// Last Modified By : Andrew Beach
// Last Modified On : Mon Nov  5 19:20:00 2021
// Update Count     : 2
//

#include "FixLabels.hpp"

#include "AST/Label.hpp"
#include "AST/Pass.hpp"
#include "AST/Stmt.hpp"
#include "ControlStruct/LabelGenerator.h"
#include "ControlStruct/MultiLevelExit.hpp"

namespace ControlStruct {

namespace {

class FixLabelsCore final : public ast::WithGuards {
        LabelToStmt labelTable;
        LabelGenerator * label_gen;
public:
        FixLabelsCore( LabelGenerator * gen = nullptr ) :
                labelTable(),
                label_gen( gen ? gen : LabelGenerator::getGenerator() )
        {}

        void previsit( const ast::FunctionDecl * );
        const ast::FunctionDecl * postvisit( const ast::FunctionDecl * );
        void previsit( const ast::Stmt * );
        void previsit( const ast::BranchStmt * );
        void previsit( const ast::LabelAddressExpr * );

        void setLabelsDef( const std::vector<ast::Label> &, const ast::Stmt * );
        void setLabelsUsage( const ast::Label & );
};

void FixLabelsCore::previsit( const ast::FunctionDecl * ) {
        GuardValue( labelTable ).clear();
}

const ast::FunctionDecl * FixLabelsCore::postvisit(
                const ast::FunctionDecl * decl ) {
        if ( nullptr == decl->stmts ) return decl;
        for ( auto kvp : labelTable ) {
                if ( nullptr == kvp.second ) {
                        SemanticError( kvp.first.location,
                                "Use of undefined label: " + kvp.first.name );
                }
        }
        return ast::mutate_field( decl, &ast::FunctionDecl::stmts,
                multiLevelExitUpdate( decl->stmts.get(), labelTable, label_gen ) );
}

void FixLabelsCore::previsit( const ast::Stmt * stmt ) {
        if ( !stmt->labels.empty() ) {
                setLabelsDef( stmt->labels, stmt );
        }
}

void FixLabelsCore::previsit( const ast::BranchStmt * stmt ) {
        if ( !stmt->labels.empty() ) {
                setLabelsDef( stmt->labels, stmt );
        }
        if ( !stmt->target.empty() ) {
                setLabelsUsage( stmt->target );
        }
}

void FixLabelsCore::previsit( const ast::LabelAddressExpr * expr ) {
        assert( !expr->arg.empty() );
        setLabelsUsage( expr->arg );
}

void FixLabelsCore::setLabelsDef(
                const std::vector<ast::Label> & labels, const ast::Stmt * stmt ) {
        assert( !labels.empty() );
        assert( stmt );

        for ( auto label : labels ) {
                if ( labelTable.find( label ) == labelTable.end() ) {
                        // Make sure to only create the entry once.
                        labelTable[ label ] = stmt;
                } else if ( nullptr != labelTable[ label ] ) {
                        // Duplicate definition, this is an error.
                        SemanticError( label.location,
                                "Duplicate definition of label: " + label.name );
                } else {
                        // Perviously used, but not defined until now.
                        labelTable[ label ] = stmt;
                }
        }
}

// Label was used, if it is new add it to the table.
void FixLabelsCore::setLabelsUsage( const ast::Label & label ) {
        if ( labelTable.find( label ) == labelTable.end() ) {
                labelTable[ label ] = nullptr;
        }
}

} // namespace

void fixLabels( ast::TranslationUnit & translationUnit ) {
        ast::Pass<FixLabelsCore>::run( translationUnit );
}

} // namespace ControlStruct

// Local Variables: //
// tab-width: 4 //
// mode: c++ //
// compile-command: "make install" //
// End: //