| ============================================= |
| Building a JIT: Per-function Lazy Compilation |
| ============================================= |
| |
| .. contents:: |
| :local: |
| |
| **This tutorial is under active development. It is incomplete and details may |
| change frequently.** Nonetheless we invite you to try it out as it stands, and |
| we welcome any feedback. |
| |
| Chapter 3 Introduction |
| ====================== |
| |
| Welcome to Chapter 3 of the "Building an ORC-based JIT in LLVM" tutorial. This |
| chapter discusses lazy JITing and shows you how to enable it by adding an ORC |
| CompileOnDemand layer the JIT from `Chapter 2 <BuildingAJIT2.html>`_. |
| |
| **To be done:** |
| |
| **(1) Describe lazy function-at-a-time JITing and how it differs from the kind |
| of eager module-at-a-time JITing that we've been doing so far.** |
| |
| **(2) Discuss CompileCallbackManagers and IndirectStubManagers.** |
| |
| **(3) Describe CompileOnDemandLayer (automates these components and builds stubs |
| and lazy compilation callbacks for IR) and how to add it to the JIT.** |
| |
| Full Code Listing |
| ================= |
| |
| Here is the complete code listing for our running example with a CompileOnDemand |
| layer added to enable lazy function-at-a-time compilation. To build this example, use: |
| |
| .. code-block:: bash |
| |
| # Compile |
| clang++ -g toy.cpp `llvm-config --cxxflags --ldflags --system-libs --libs core orc native` -O3 -o toy |
| # Run |
| ./toy |
| |
| Here is the code: |
| |
| .. literalinclude:: ../../examples/Kaleidoscope/BuildingAJIT/Chapter3/KaleidoscopeJIT.h |
| :language: c++ |
| |
| `Next: Extreme Laziness -- Using Compile Callbacks to JIT directly from ASTs <BuildingAJIT4.html>`_ |