excompiler.cpp

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/*
 *  GiNaC Copyright (C) 1999-2023 Johannes Gutenberg University Mainz, Germany
 *
 *  This program is free software; you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License as published by
 *  the Free Software Foundation; either version 2 of the License, or
 *  (at your option) any later version.
 *
 *  This program is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *  GNU General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public License
 *  along with this program; if not, write to the Free Software
 *  Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
 */
 
#include "excompiler.h"
 
#ifdef HAVE_CONFIG_H
#include "config.h"
#endif
 
#include "ex.h"
#include "lst.h"
#include "operators.h"
#include "relational.h"
#include "symbol.h"
 
#ifdef HAVE_LIBDL
# include <dlfcn.h>
#endif // def HAVE_LIBDL
#ifdef HAVE_UNISTD_H
# include <unistd.h>
#else
# ifdef _MSC_VER
#  include <io.h>  // for close(3)
# endif // def _MSC_VER
#endif // def HAVE_UNISTD_H
#include <cstdlib>
#include <fstream>
#include <ios>
#include <sstream>
#include <stdexcept>
#include <string>
#include <vector>
 
namespace GiNaC {
 
#ifdef HAVE_LIBDL
 
class excompiler
{
    struct filedesc
    {
        void* module;
        std::string name; 
        bool clean_up; 
    };
    std::vector<filedesc> filelist; 
public:
    ~excompiler()
    {
        for (auto it = filelist.begin(); it != filelist.end(); ++it) {
            clean_up(it);
        }
    }
    void add_opened_module(void* module, const std::string& name, bool clean_up)
    {
        filedesc fd;
        fd.module = module;
        fd.name = name;
        fd.clean_up = clean_up;
        filelist.push_back(fd);
    }
    void clean_up(const std::vector<filedesc>::const_iterator it)
    {
        dlclose(it->module);
        if (it->clean_up) {
            remove(it->name.c_str());
        }
    }
    void create_src_file(std::string& filename, std::ofstream& ofs)
    {
        if (filename.empty()) {
            // fill filename with unique random word
            const char* filename_pattern = "./GiNaCXXXXXX";
            char* new_filename = new char[strlen(filename_pattern)+1];
            strcpy(new_filename, filename_pattern);
            int fd = mkstemp(new_filename);
            if (fd == -1) {
                delete[] new_filename;
                throw std::runtime_error("mkstemp failed");
            }
            filename = std::string(new_filename);
            ofs.open(new_filename, std::ios::out);
            close(fd);
            delete[] new_filename;
        } else {
            // use parameter as filename
            ofs.open(filename.c_str(), std::ios::out);
        }
        
        if (!ofs) {
            throw std::runtime_error("could not create source code file for compilation");
        }
 
        ofs << "#include <stddef.h> " << std::endl;
        ofs << "#include <stdlib.h> " << std::endl;
        ofs << "#include <math.h> " << std::endl;
        ofs << std::endl;
    }
    void compile_src_file(const std::string filename, bool clean_up)
    {
        std::string strcompile = LIBEXECDIR "ginac-excompiler " + filename;
        if (system(strcompile.c_str())) {
            throw std::runtime_error("excompiler::compile_src_file: error compiling source file!");
        }
        if (clean_up) {
            remove(filename.c_str());
        }
    }
    void* link_so_file(const std::string filename, bool clean_up)
    {
        void* module = nullptr;
        module = dlopen(filename.c_str(), RTLD_NOW);
        if (module == nullptr) {
            throw std::runtime_error("excompiler::link_so_file: could not open compiled module!");
        }
 
        add_opened_module(module, filename, clean_up);
 
        return dlsym(module, "compiled_ex");
    }
    void unlink(const std::string filename)
    {
        for (auto it = filelist.begin(); it != filelist.end();) {
            if (it->name == filename) {
                clean_up(it);
                it = filelist.erase(it);
            } else {
                ++it;
            }
        }
    }
};
 
static excompiler global_excompiler;
 
void compile_ex(const ex& expr, const symbol& sym, FUNCP_1P& fp, const std::string filename)
{
    symbol x("x");
    ex expr_with_x = expr.subs(lst{sym==x});
 
    std::ofstream ofs;
    std::string unique_filename = filename;
    global_excompiler.create_src_file(unique_filename, ofs);
 
    ofs << "double compiled_ex(double x)" << std::endl;
    ofs << "{" << std::endl;
    ofs << "double res = ";
    expr_with_x.print(GiNaC::print_csrc_double(ofs));
    ofs << ";" << std::endl;
    ofs << "return(res); " << std::endl;
    ofs << "}" << std::endl;
 
    ofs.close();
 
    global_excompiler.compile_src_file(unique_filename, filename.empty());
    // This is not standard compliant! ... no conversion between
    // pointer-to-functions and pointer-to-objects ...
    fp = (FUNCP_1P) global_excompiler.link_so_file(unique_filename+".so", filename.empty());
}
 
void compile_ex(const ex& expr, const symbol& sym1, const symbol& sym2, FUNCP_2P& fp, const std::string filename)
{
    symbol x("x"), y("y");
    ex expr_with_xy = expr.subs(lst{sym1==x, sym2==y});
 
    std::ofstream ofs;
    std::string unique_filename = filename;
    global_excompiler.create_src_file(unique_filename, ofs);
 
    ofs << "double compiled_ex(double x, double y)" << std::endl;
    ofs << "{" << std::endl;
    ofs << "double res = ";
    expr_with_xy.print(GiNaC::print_csrc_double(ofs));
    ofs << ";" << std::endl;
    ofs << "return(res); " << std::endl;
    ofs << "}" << std::endl;
 
    ofs.close();
 
    global_excompiler.compile_src_file(unique_filename, filename.empty());
    // This is not standard compliant! ... no conversion between
    // pointer-to-functions and pointer-to-objects ...
    fp = (FUNCP_2P) global_excompiler.link_so_file(unique_filename+".so", filename.empty());
}
 
void compile_ex(const lst& exprs, const lst& syms, FUNCP_CUBA& fp, const std::string filename)
{
    lst replacements;
    for (std::size_t count=0; count<syms.nops(); ++count) {
        std::ostringstream s;
        s << "a[" << count << "]";
        replacements.append(syms.op(count) == symbol(s.str()));
    }
 
    std::vector<ex> expr_with_cname;
    for (std::size_t count=0; count<exprs.nops(); ++count) {
        expr_with_cname.push_back(exprs.op(count).subs(replacements));
    }
 
    std::ofstream ofs;
    std::string unique_filename = filename;
    global_excompiler.create_src_file(unique_filename, ofs);
 
    ofs << "void compiled_ex(const int* an, const double a[], const int* fn, double f[])" << std::endl;
    ofs << "{" << std::endl;
    for (std::size_t count=0; count<exprs.nops(); ++count) {
        ofs << "f[" << count << "] = ";
        expr_with_cname[count].print(GiNaC::print_csrc_double(ofs));
        ofs << ";" << std::endl;
    }
    ofs << "}" << std::endl;
 
    ofs.close();
 
    global_excompiler.compile_src_file(unique_filename, filename.empty());
    // This is not standard compliant! ... no conversion between
    // pointer-to-functions and pointer-to-objects ...
    fp = (FUNCP_CUBA) global_excompiler.link_so_file(unique_filename+".so", filename.empty());
}
 
void link_ex(const std::string filename, FUNCP_1P& fp)
{
    // This is not standard compliant! ... no conversion between
    // pointer-to-functions and pointer-to-objects ...
    fp = (FUNCP_1P) global_excompiler.link_so_file(filename, false);
}
 
void link_ex(const std::string filename, FUNCP_2P& fp)
{
    // This is not standard compliant! ... no conversion between
    // pointer-to-functions and pointer-to-objects ...
    fp = (FUNCP_2P) global_excompiler.link_so_file(filename, false);
}
 
void link_ex(const std::string filename, FUNCP_CUBA& fp)
{
    // This is not standard compliant! ... no conversion between
    // pointer-to-functions and pointer-to-objects ...
    fp = (FUNCP_CUBA) global_excompiler.link_so_file(filename, false);
}
 
void unlink_ex(const std::string filename)
{
    global_excompiler.unlink(filename);
}
 
#else // def HAVE_LIBDL
 
/*
 * In case no working libdl has been found by configure, the following function
 * stubs preserve the interface. Every function just raises an exception.
 */
 
void compile_ex(const ex& expr, const symbol& sym, FUNCP_1P& fp, const std::string filename)
{
    throw std::runtime_error("compile_ex has been disabled because of missing libdl!");
}
 
void compile_ex(const ex& expr, const symbol& sym1, const symbol& sym2, FUNCP_2P& fp, const std::string filename)
{
    throw std::runtime_error("compile_ex has been disabled because of missing libdl!");
}
 
void compile_ex(const lst& exprs, const lst& syms, FUNCP_CUBA& fp, const std::string filename)
{
    throw std::runtime_error("compile_ex has been disabled because of missing libdl!");
}
 
void link_ex(const std::string filename, FUNCP_1P& fp)
{
    throw std::runtime_error("link_ex has been disabled because of missing libdl!");
}
 
void link_ex(const std::string filename, FUNCP_2P& fp)
{
    throw std::runtime_error("link_ex has been disabled because of missing libdl!");
}
 
void link_ex(const std::string filename, FUNCP_CUBA& fp)
{
    throw std::runtime_error("link_ex has been disabled because of missing libdl!");
}
 
void unlink_ex(const std::string filename)
{
    throw std::runtime_error("unlink_ex has been disabled because of missing libdl!");
}
 
#endif // def HAVE_LIBDL
 
} // namespace GiNaC