linker.js

/* _________________________________________________________________________
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/**
@fileOverview
Code block linker implementation.

@author
Maxime Chevalier-Boisvert
*/

/**
Link the imported references in a code block
*/
function linkCode(codeBlock, backend, params)
{
    assert (
        codeBlock instanceof CodeBlock,
        'invalid code block'
    );

    // For each imported value in the code block
    for (var i = 0; i < codeBlock.imports.length; ++i)
    {
        var imported = codeBlock.imports[i];

        // Get a reference to the value
        var value = imported.value;

        // Set the write position
        codeBlock.setWritePos(imported.pos);

        // If this is a static function reference
        if (value instanceof IRFunction)
        {
            // If the function has no compiled code block
            if ((value.codeBlock instanceof CodeBlock) === false)
            {
                log.debug('function not linked: ' + value.getValName());
                continue;
            }

            log.debug('*** linking func: ' + value.getValName());

            assert (
                value.codeBlock instanceof CodeBlock,
                'invalid function code block'
            );

            // Get the default entry point address
            var entryAddr = value.codeBlock.getExportAddr('ENTRY_DEFAULT');

            // Write the entry point address
            codeBlock.writeBytes(entryAddr);
        }
        
        // If this is a C function reference
        else if (value instanceof CFunction)
        {
            log.debug('*** linking C func: ' + value.getValName());

            assert (
                value.funcPtr instanceof Array,
                'invalid function pointer'
            );

            // Write the function address
            codeBlock.writeBytes(value.funcPtr);
        }

        // If this is a string value
        else if (value instanceof IRConst && value.isString())
        {
            // If strings cannot yet be linked, do nothing
            if ((params.getStrObj instanceof Function) == false)
                continue;

            // Get the address for this string
            var stringAddr = params.getStrObj(value.value);

            // Write the string address
            codeBlock.writeBytes(stringAddr);
        }

        else
        {
            error('invalid link value');
        }
    }
}