source: src/CodeGen/FixMain.cc@ c333ed2

//
// 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.
//
// FixMain.cc -- Tools to change a Cforall main into a C main.
//
// Author           : Thierry Delisle
// Created On       : Thr Jan 12 14:11:09 2017
// Last Modified By :
// Last Modified On :
// Update Count     : 1
//

#include "FixMain.h"

#include <cassert>                 // for assert, assertf
#include <fstream>                 // for operator<<, basic_ostream::operator<<
#include <list>                    // for list
#include <string>                  // for operator<<

#include "AST/Decl.hpp"
#include "AST/Pass.hpp"
#include "AST/Type.hpp"
#include "AST/Vector.hpp"
#include "Common/SemanticError.h"  // for SemanticError
#include "CodeGen/GenType.h"       // for GenType
#include "SymTab/Mangler.h"

namespace CodeGen {

namespace {

struct FindMainCore final {
        ast::FunctionDecl const * main_declaration = nullptr;

        void previsit( ast::FunctionDecl const * decl ) {
                if ( isMain( decl ) ) {
                        if ( main_declaration ) {
                                SemanticError( decl, "Multiple definition of main routine" );
                        }
                        main_declaration = decl;
                }
        }
};

std::string genTypeAt( const ast::vector<ast::Type> & types, size_t at ) {
        return genType( types[at], "", Options( false, false, false, false ) );
}

ast::ObjectDecl * makeIntObj(){
        return new ast::ObjectDecl( CodeLocation(), "",
                new ast::BasicType( ast::BasicKind::SignedInt ) );
}

ast::ObjectDecl * makeCharStarStarObj() {
        return new ast::ObjectDecl( CodeLocation(), "",
                new ast::PointerType(
                        new ast::PointerType(
                                new ast::BasicType( ast::BasicKind::Char ) ) ) );
}

std::string getMangledNameOfMain(
                ast::vector<ast::DeclWithType> && params, ast::ArgumentFlag isVarArgs ) {
        ast::ptr<ast::FunctionDecl> decl = new ast::FunctionDecl(
                CodeLocation(),
                "main",
                ast::vector<ast::TypeDecl>(),
                ast::vector<ast::DeclWithType>(),
                std::move( params ),
                { makeIntObj() },
                nullptr,
                ast::Storage::Classes(),
                ast::Linkage::Spec(),
                ast::vector<ast::Attribute>(),
                ast::Function::Specs(),
                isVarArgs
        );
        return Mangle::mangle( decl.get() );
}

std::string getMangledNameOf0ParameterMain() {
        return getMangledNameOfMain( {}, ast::VariableArgs );
}

std::string getMangledNameOf2ParameterMain() {
        return getMangledNameOfMain( {
                makeIntObj(),
                makeCharStarStarObj(),
        }, ast::FixedArgs );
}

bool is_main( const std::string & mangled_name ) {
        // This breaks if you move it out of the function.
        static const std::string mangled_mains[] = {
                getMangledNameOf0ParameterMain(),
                getMangledNameOf2ParameterMain(),
                //getMangledNameOf3ParameterMain(),
        };

        for ( auto main_name : mangled_mains ) {
                if ( main_name == mangled_name ) return true;
        }
        return false;
}

struct FixLinkageCore final {
        ast::Linkage::Spec const spec;
        FixLinkageCore( ast::Linkage::Spec spec ) : spec( spec ) {}

        ast::FunctionDecl const * previsit( ast::FunctionDecl const * decl ) {
                if ( decl->name != "main" ) return decl;
                return ast::mutate_field( decl, &ast::FunctionDecl::linkage, spec );
        }
};

} // namespace

bool isMain( const ast::FunctionDecl * decl ) {
        if ( std::string("main") != decl->name ) {
                return false;
        }
        return is_main( Mangle::mangle( decl, Mangle::Type ) );
}

void fixMainLinkage( ast::TranslationUnit & translationUnit,
                bool replace_main ) {
        ast::Linkage::Spec const spec =
                ( replace_main ) ? ast::Linkage::Cforall : ast::Linkage::C;
        ast::Pass<FixLinkageCore>::run( translationUnit, spec );
}

void fixMainInvoke( ast::TranslationUnit & translationUnit,
                std::ostream &os, const char * bootloader_filename ) {

        ast::Pass<FindMainCore> main_finder;
        ast::accept_all( translationUnit, main_finder );
        if ( nullptr == main_finder.core.main_declaration ) return;

        ast::FunctionDecl * main_declaration =
                ast::mutate( main_finder.core.main_declaration );

        main_declaration->mangleName = Mangle::mangle( main_declaration );

        os << "static inline int invoke_main(int argc, char* argv[], char* envp[]) { (void)argc; (void)argv; (void)envp; return ";
        os << main_declaration->scopedMangleName() << "(";
        const auto& params = main_declaration->type->params;
        switch ( params.size() ) {
                case 3: os << "(" << genTypeAt(params, 0) << ")argc, (" << genTypeAt(params, 1) << ")argv, (" << genTypeAt(params, 2) << ")envp"; break;
                case 2: os << "(" << genTypeAt(params, 0) << ")argc, (" << genTypeAt(params, 1) << ")argv"; break;
                case 0: break;
                default : assert(false);
        }
        os << "); }\n";

        std::ifstream bootloader( bootloader_filename, std::ios::in );
        assertf( bootloader.is_open(), "cannot open bootloader.c\n" );
        os << bootloader.rdbuf();
}

} // namespace CodeGen