source: src/Validate/InitializerLength.cpp @ 16ba4897

//
// Cforall Version 1.0.0 Copyright (C) 2018 University of Waterloo
//
// The contents of this file are covered under the licence agreement in the
// file "LICENCE" distributed with Cforall.
//
// InitializerLength.cpp -- Calculate the length of arrays from initializers.
//
// Author           : Andrew Beach
// Created On       : Fri Nov 12 11:46:00 2021
// Last Modified By : Andrew Beach
// Last Modified On : Fri Nov 12 13:35:00 2021
// Update Count     : 0
//

#include "InitializerLength.hpp"

#include "AST/Expr.hpp"
#include "AST/Decl.hpp"
#include "AST/Pass.hpp"
#include "AST/TranslationUnit.hpp"

namespace Validate {

namespace {

/// for array types without an explicit length, compute the length and store it so that it
/// is known to the rest of the phases. For example,
///   int x[] = { 1, 2, 3 };
///   int y[][2] = { { 1, 2, 3 }, { 1, 2, 3 } };
///   char z[] = "hello";
/// here x and y are known at compile-time to have length 3, so change this into
///   int x[3] = { 1, 2, 3 };
///   int y[3][2] = { { 1, 2, 3 }, { 1, 2, 3 } };
///   char z[6] = "hello";
struct InitializerLength {
        const ast::ObjectDecl * previsit( const ast::ObjectDecl * decl );
};

ast::ConstantExpr * makeDimension( const ast::ObjectDecl * decl ) {
        if ( auto init = decl->init.as<ast::ListInit>() ) {
                return ast::ConstantExpr::from_ulong( decl->location, init->size() );
        } else if ( auto init = decl->init.as<ast::SingleInit>() ) {
                if ( auto constant = init->value.as<ast::ConstantExpr>() ) {
                        if ( auto type = constant->result.as<ast::ArrayType>() ) {
                                if ( auto dim = type->dimension.as<ast::ConstantExpr>() ) {
                                        ast::ConstantExpr * dimension = ast::deepCopy( dim );
                                        dimension->location = decl->location;
                                        return dimension;
                                }
                        }
                }
        }
        return nullptr;
}

const ast::ObjectDecl * InitializerLength::previsit( const ast::ObjectDecl * decl ) {
        if ( auto type = decl->type.as<ast::ArrayType>() ) {
                if ( type->dimension ) return decl;
                if ( auto dimension = makeDimension( decl ) ) {
                        ast::ObjectDecl * mutDecl = ast::mutate( decl );
                        ast::ArrayType * mutType = ast::mutate( type );
                        mutType->dimension = dimension;
                        mutDecl->type = mutType;
                        return mutDecl;
                }
        }
        return decl;
}

} // namespace

void setLengthFromInitializer( ast::TranslationUnit & translationUnit ) {
        ast::Pass<InitializerLength>::run( translationUnit );
}

} // namespace Validate

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