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Getting started with LLVM core libraries

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Getting started with LLVM core libraries

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Getting started with LLVM core libraries
Aug, 2014 | 314 pages
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Table of Contents (17 chapters)
Getting Started with LLVM Core Libraries
Getting Started with LLVM Core Libraries
Credits
Credits
About the Authors
About the Authors
About the Reviewers
About the Reviewers
www.PacktPub.com
www.PacktPub.com
Preface
Preface
Free Chapter
1
Build and Install LLVM
Build and Install LLVM
Understanding LLVM versions
Obtaining prebuilt packages
Building from sources
Summary
2
External Projects
External Projects
Introducing Clang extras
Using the DragonEgg plugin
Summary
3
Tools and Design
Tools and Design
Introducing LLVM's basic design principles and its history
Understanding LLVM today
Interacting with the compiler driver
Using standalone tools
Delving into the LLVM internal design
Writing your first LLVM project
Navigating the LLVM source – general advice
Summary
4
The Frontend
The Frontend
Introducing Clang
Learning the frontend phases with Clang
Putting it together
Summary
5
The LLVM Intermediate Representation
The LLVM Intermediate Representation
Overview
Exercising basic tools to manipulate the IR formats
Introducing the LLVM IR language syntax
Writing a custom LLVM IR generator
Optimizing at the IR level
Summary
6
The Backend
The Backend
Overview
Learning the backend code structure
Knowing the backend libraries
Learning how to use TableGen for LLVM backends
Understanding the instruction selection phase
Scheduler
Machine instructions
Register allocation
Prologue and epilogue
Understanding the machine code framework
Writing your own machine pass
Summary
7
The Just-in-Time Compiler
The Just-in-Time Compiler
Getting to know the LLVM JIT engine basics
Introducing the llvm::JIT framework
Introducing the llvm::MCJIT framework
Using LLVM JIT compilation tools
Other resources
Summary
8
Cross-platform Compilation
Cross-platform Compilation
Comparing GCC and LLVM
Understanding target triples
Preparing your toolchain
Cross-compiling with Clang command-line arguments
Generating a Clang cross-compiler
Testing
Additional resources
Summary
9
The Clang Static Analyzer
The Clang Static Analyzer
Understanding the role of a static analyzer
Testing the static analyzer
Extending the static analyzer with your own checkers
More resources
Summary
10
Clang Tools with LibTooling
Clang Tools with LibTooling
Generating a compile command database
The clang-tidy tool
Refactoring tools
Writing your own tool
More resources
Summary
Index
Index

Introducing the llvm::JIT framework

The JIT class and its framework represent the older engine and are implemented by using different parts of the LLVM code generator. It will be removed after LLVM 3.5. Even though the engine is mostly target-independent, each target must implement the binary instruction emission step for its specific instructions.

Writing blobs to memory

The JIT class emits binary instructions by using JITCodeEmitter, a MachineCodeEmitter subclass. The MachineCodeEmitter class is used for machine code emission that is not related to the new Machine Code (MC) framework—even though it is old, it is still present to support the functionality of the JIT class. The limitations are that only a few targets are supported, and for the supported targets, not all target features are available.

The MachineCodeEmitter class has methods that facilitate the following tasks:

  • To allocate space (allocateSpace()) for the current function to be emitted

  • To write binary blobs to memory buffers ...

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