Ticket #9437: how-to-reproduce.cpp

#include <cstdlib>
#include <iostream>

#include <boost/context/all.hpp>

namespace {
    template< std::size_t Max, std::size_t Default, std::size_t Min >
    class simple_stack_allocator
    {
    public:
        static std::size_t maximum_stacksize()
        { return Max; }

        static std::size_t default_stacksize()
        { return Default; }

        static std::size_t minimum_stacksize()
        { return Min; }

        void * allocate( std::size_t size) const
        {
            BOOST_ASSERT( minimum_stacksize() <= size);
            BOOST_ASSERT( maximum_stacksize() >= size);

            void * limit = std::calloc( size, sizeof( char) );
            if ( ! limit) throw std::bad_alloc();

            return static_cast< char * >( limit) + size;
        }

        void deallocate( void * vp, std::size_t size) const
        {
            BOOST_ASSERT( vp);
            BOOST_ASSERT( minimum_stacksize() <= size);
            BOOST_ASSERT( maximum_stacksize() >= size);

            void * limit = static_cast< char * >( vp) - size;
            std::free( limit);
        }
    };
}

namespace sample {
    namespace ctx = yboost::context;

    typedef simple_stack_allocator<
        8 * 1024 * 1024, // 8MB
        64 * 1024, // 64kB
        8 * 1024 // 8kB
    > stack_allocator;

    ctx::fcontext_t fcm;
    ctx::fcontext_t* fc = 0;

    void do_throw() {
        throw std::exception();
    }

    void routine(intptr_t) {
        try {
            ctx::jump_fcontext(fc, &fcm, 0);
            do_throw();
        } catch(std::exception) {
            std::cout << "exception caught" << std::endl;
        }
        ctx::jump_fcontext(fc, &fcm, 0);
    }

    void try_jump() {
        try {
            ctx::jump_fcontext(&fcm, fc, 0);
        } catch (...) {
        }
    }

    void test() {
        stack_allocator alloc;
        void* base = alloc.allocate(stack_allocator::default_stacksize());
        fc = ctx::make_fcontext(base, stack_allocator::default_stacksize(), routine);

        try_jump();
        ctx::jump_fcontext(&fcm, fc, 0);
    }
}


int main(int argc, const char * argv[]) {
    sample::test();
}