4.6. Execution engine

The execution engine is where actual code generation and execution happens. The currently supported LLVM version (LLVM 3.8) exposes one execution engine, named MCJIT.

4.6.1. Functions

llvmlite.binding.create_mcjit_compiler(module, target_machine)

Create a MCJIT-powered engine from the given module and target_machine. A ExecutionEngine instance is returned. The module need not contain any code.


Ensure the system allows creation of executable memory ranges for JIT-compiled code. If some security mechanism (such as SELinux) prevents it, an exception is raised. Otherwise the function returns silently.

Calling this function early can help diagnose system configuration issues, instead of letting JIT-compiled functions crash mysteriously.

4.6.2. The ExecutionEngine class

class llvmlite.binding.ExecutionEngine

A wrapper around a LLVM execution engine. The following methods and properties are available:


Add the module (a ModuleRef instance) for code generation. When this method is called, ownership of the module is transferred to the execution engine.


Make sure all modules owned by the execution engine are fully processed and “usable” for execution.



This function is deprecated. User should use ExecutionEngine.get_function_address() and ExecutionEngine.get_global_value_address() instead

Return the address of the function value gv, as an integer. The value should have been looked up on one of the modules owned by the execution engine.


This method may implicitly generate code for the object being looked up.


This function is formerly an alias to get_pointer_to_global(), which is now removed because it returns an invalid address in MCJIT when given a non-function global value.


Return the address of the function named name as an integer.


Return the address of the global value named name as an integer.


Remove the module (a ModuleRef instance) from the modules owned by the execution engine. This allows releasing the resources owned by the module without destroying the execution engine.

set_object_cache(notify_func=None, getbuffer_func=None)

Set the object cache callbacks for this engine.

notify_func, if given, is called whenever the engine has finished compiling a module. It is passed two arguments (module, buffer). The first argument module is a ModuleRef instance. The second argument buffer is a bytes object of the code generated for the module. The return value is ignored.

getbuffer_func, if given, is called before the engine starts compiling a module. It is passed one argument, module, a ModuleRef instance of the module being compiled. The function can return None, in which case the module will be compiled normally. Or it can return a bytes object of native code for the module, which will bypass compilation entirely.


The TargetData used by the execution engine.