source: src/ControlStruct/TranslateEnumRange.cpp @ 9739c56f

#include "TranslateEnumRange.hpp"

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

namespace ControlStruct {

namespace {

struct TranslateEnumRangeCore {
        const ast::Stmt * postvisit( const ast::ForStmt * stmt );
};

const ast::Stmt * TranslateEnumRangeCore::postvisit( const ast::ForStmt * stmt ) {
        if ( !stmt->range_over ) return stmt;
        auto mutStmt = ast::mutate( stmt );
        auto & location = mutStmt->location;

        if ( auto declStmt = mutStmt->inits.front().as<ast::DeclStmt>() ) {
                if ( auto objDecl = declStmt->decl.as<ast::ObjectDecl>() ) {
                        if ( !objDecl->init ) {
                                ast::SingleInit * newInit = new ast::SingleInit( location,
                                        ast::UntypedExpr::createCall( location,
                                                mutStmt->is_inc ? "lowerBound" : "upperBound", {} ),
                                        ast::ConstructFlag::MaybeConstruct
                                );
                                auto objDeclWithInit = ast::mutate_field( objDecl, &ast::ObjectDecl::init, newInit );
                                auto declWithInit = ast::mutate_field( declStmt, &ast::DeclStmt::decl, objDeclWithInit );
                                mutStmt->inits[0] = declWithInit;
                        }
                }
        }

        auto declStmt = mutStmt->inits.front().strict_as<ast::DeclStmt>();
        auto initDecl = declStmt->decl.strict_as<ast::ObjectDecl>();
        auto indexName = initDecl->name;

        // Both inc and dec check if the current posn less than the number of enumerator
        // for dec, it keeps call pred until it passes 0 (the first enumerator) and underflow,
        // it wraps around and become unsigned max
        ast::UntypedExpr * condition = ast::UntypedExpr::createCall( location,
                mutStmt->is_inc ? "?<=?" : "?>=?",
                {
                        new ast::NameExpr( location, indexName ),
                        ast::UntypedExpr::createCall( location,
                                mutStmt->is_inc ? "upperBound" : "lowerBound", {} )
                } );
        auto increment = ast::UntypedExpr::createCall( location,
                mutStmt->is_inc ? "succ_unsafe" : "pred_unsafe",
                { new ast::NameExpr( location, indexName ) } );
        auto assig = ast::UntypedExpr::createAssign( location,
                new ast::NameExpr( location, indexName ), increment );
        mutStmt->cond = condition;
        mutStmt->inc = assig;
        return mutStmt;
}

} // namespace

void translateEnumRange( ast::TranslationUnit & translationUnit ) {
        ast::Pass<TranslateEnumRangeCore>::run( translationUnit );
}

} // namespace ControlStruct