Using LLVM

LLVM documentation is very good. Of particular relevance for Proteus are ll files and LLVM tools. One point to note is that the man pages for the tools proved to be an invaluable source of information about options and usage. The Getting Started guide provides a simple example of usage.

Simple commands to produce ll files all assume that llvm and llvm-gcc frontend are in your path and are given as instructions to be entered at the command prompt

Produce an ll file from single C source
llvm-gcc -S --emit-llvm program.c -o program.ll
Produce an ll file from single C++ source
llvm-g++ -S --emit-llvm -o program.ll
Produce an ll file from multiple C++ source
llvm-g++ -c --emit-llvm -o part1.bc llvm-g++ -c --emit-llvm -o part2.bc llvm-g++ -c --emit-llvm -o part3.bc
Now to link them together
llvm-ld -disable-opt -o combined part1.bc part2.bc part3.bc
Run the optimisations on the combined file and output an ll file
opt -S -disable-inlining -O3 -std-compile-opts -std-link-opts combined.bc -o combined-optimized.ll