pz_code.cpp

/*
 * Plasma bytecode code structures and functions
 * vim: ts=4 sw=4 et
 *
 * Copyright (C) Plasma Team
 * Distributed under the terms of the MIT license, see ../LICENSE.code
 */

#include "pz_common.h"

#include "pz_code.h"
#include "pz_gc.h"

namespace pz {

Proc::Proc(NoGCScope & gc_cap, String name, bool is_builtin,
           unsigned size)
    : m_code_size(size)
    , m_name(name)
    , m_is_builtin(is_builtin)
    , m_contexts(gc_cap, 0)
{
    m_code = (uint8_t *)gc_cap.alloc_bytes(size, META);
    heap_set_meta_info(&gc_cap.heap(), code(), this);
}

void Proc::add_context(GCCapability & gc_cap, unsigned offset,
                       String filename, unsigned line)
{
    if (m_filename.hasValue()) {
        assert(m_filename.value().equals(filename));
    } else {
        m_filename.set(filename);
    }

    set_context(gc_cap, offset, line);
}

void Proc::add_context(GCCapability & gc_cap, unsigned offset, unsigned line)
{
    assert(m_filename.hasValue());
    set_context(gc_cap, offset, line);
}

void Proc::no_context(GCCapability & gc_cap, unsigned offset)
{
    set_context(gc_cap, offset, 0);
}

void Proc::set_context(GCCapability & gc_cap, unsigned offset, unsigned value)
{
    bool res = m_contexts.append(gc_cap, OffsetContext(offset, value));

    // We expect the return code to be true unless GCCapability is a
    // NoGCScope, and it probably isn't.
    if (!res) {
        assert(res);
    }
    // Check that this isn't a NoGCScope so we know to fix the above
    // assumption if that changes.
    assert(gc_cap.can_gc());
}

unsigned Proc::line(unsigned offset, unsigned * last_lookup) const
{
    unsigned start;
    if (*last_lookup == 0 || m_contexts[*last_lookup - 1].offset > offset) {
        start = 0;
    } else {
        start = *last_lookup - 1;
    }

    /*
     * The loop condition is such that i and i+1 are both within the bounds
     * of m_contexts.
     */
    for (unsigned i = start; i + 1 < m_contexts.size(); i++) {
        // If the current offset is between this and the next.
        if ((m_contexts[i].offset <= offset) &&
            (m_contexts[i+1].offset > offset))
        {
            *last_lookup = i;
            return m_contexts[i].line;
        }
    }
    if (m_contexts.size() > 0 && m_contexts.back().offset <= offset) {
        *last_lookup = m_contexts.size() - 1;
        return m_contexts.back().line;
    }

    return 0;
}

}  // namespace pz