What is LLVM optimization?

What is LLVM optimization?

LLVM features powerful intermodular optimizations which can be used at link time. Link Time Optimization (LTO) is another name for intermodular optimization when performed during the link stage. This document describes the interface and design between the LTO optimizer and the linker.

How LLVM optimize a function?

How LLVM Optimizes a Function

1. A frontend that converts source code into an intermediate representation (IR).
2. A target-independent optimization pipeline: a sequence of passes that successively rewrite the IR to eliminate inefficiencies and forms that cannot be readily translated into machine code.

How does link time optimization work?

Link Time Optimization (LTO) refers to program optimization during linking. The linker pulls all object files together and combines them into one program. The linker can see the whole of the program, and can therefore do whole-program analysis and optimization.

How do I write a LLVM pass?

Start out with:

1. #include “llvm/Pass.h” #include “llvm/IR/Function.h” #include “llvm/Support/raw_ostream.h”
2. using namespace llvm;
3. namespace {
4. struct Hello : public FunctionPass {
5. static char ID; Hello() : FunctionPass(ID) {}
6. bool runOnFunction(Function &F) override { errs() << “Hello: “; errs().
7. char Hello::ID = 0;

How do I enable link time optimization?

How to enable link time optimizations?

1. Add option -flto to the invocation of compiler.
2. Add option -flto to the invocation of the linker. Additionally, you need to add all options from the compiler invocations to the invocation of the linker.

Is LLVM a library?

LLVM produces two types of libraries: archives (ending in . a) and objects (ending in .o). However, both are libraries.

Is LLVM a VM?

LLVM isn’t a virtual machine. LLVM is not a virtual machine. It’s a compiler infrastructure.

What is LLC in LLVM?

DESCRIPTION. The llc command compiles LLVM source inputs into assembly language for a specified architecture. The assembly language output can then be passed through a native assembler and linker to generate a native executable.