LLVM-Examples

LLVM Examples and Code samples. LLVM Passes. Based on llvm-project Clone the LLVM Repository in the $HOME directory or change the paths in the MAKEFILEs to point to the build directory of the LLVM.

# Clone
$ git clone https://github.com/llvm/llvm-project.git

# Change directory
$ cd llvm-project

# Install the essential packages with make and cmake.
$ sudo apt-get install make ninja-build cmake cmake-data binutils build-essentials python3 python3-pip

# llvm cmake command 
$ cmake \
    -S llvm -B build -Wno-dev -GNinja \
    -DCMAKE_INSTALL_PREFIX=/usr \
    -DLLVM_ENABLE_PROJECTS="llvm;compiler-rt;clang;clang-tools-extra;lldb;lld;mlir" \
    -DLLVM_BUILD_RUNTIMES="libcxx;libcxxabi" \
    -DLLVM_BINUTILS_INCDIR=$HOME/binutils/include \
    -DCMAKE_BUILD_TYPE=Release \
    -DLLVM_ENABLE_RTTI=ON \
    -DLLVM_ENABLE_FFI=ON \
    -DLLVM_BUILD_TESTS=ON \
    -DLLVM_INSTALL_UTILS=ON

$ cd build && ninja -j10 all

Installing from Docker

Check build commands in the Dockerfile for more information on installing LLVM on local machine.

$ docker build -f DockerFile -t prodrelworks/llvm-examples:latest .
$ docker run --name llvm-examples --ulimit stack=10000000:10000000 \
  --cpus=4 --memory=20g -it prodrelworks/llvm-examples:latest

Running Examples.

$ cd NewPMExample
$ make clean
$ make all

Examples & Implementations :

• Source Level Debugging
• llvm::LoopInfo in the runOnModule
• Analysing CFGs with LLVM
• A tutorial on how to write a compiler using LLVM

References & Links :

• LLVM Get Started

• Learning Compilers

• Learning Compilers/LLVM: How to start?

• LLVM-12 Book

• LLVM Passes

• LLVM GitHub Monorepo

• Clang AST LLVM

• Legacy Pass Example : See folder.

  • LLVM : What is a pass? Legacy Pass Example

• New LLVM Pass Manager :

  • LLVM : New Pass Manager
  • LLVM : Writing a new pass

• For function paraments as operands, you can get it get it via Function Argumentslist()

  • Function Parameters LLVM Function
  • Value Reference
  • User class : for getnumoperands, getoperands

• Some other differences are listed here. Even C++ one is quadratic probed.

  • https://llvm.org/docs/ProgrammersManual.html#llvm-adt-densemap-h

• Where is "emit-llvm"? ASMWritter AsmWritter.cpp.

  • https://github.com/llvm-mirror/llvm/blob/master/tools/gold/gold-plugin.cpp#L232
  • https://www.cs.cornell.edu/~asampson/blog/llvm.html

• LLVM Data Structures :

  • https://llvm.org/docs/ProgrammersManual.html#picking-the-right-data-structure-for-a-task

• LLVM RTTI :

  • https://llvm.org/docs/HowToSetUpLLVMStyleRTTI.html#id1

• Inspection & Traversal over CFG in IR :

  • Inspection & Traversal Routines over CFG
  • LLVM : Making simple manipulations