What is IR in LLVM?
LLVM IR is a low-level intermediate representation used by the LLVM compiler framework. You can think of LLVM IR as a platform-independent assembly language with an infinite number of function local registers. Front-end: compiles source language to IR. Middle-end: optimizes IR. Back-end: compiles IR to machine code.
How is LLVM compiled?
How A LLVM Compiler Works. On the front end, the LLVM compiler infrastructure uses clang — a compiler for programming languages C, C++ and CUDA — to turn source code into an interim format. Then the LLVM clang code generator on the back end turns the interim format into final machine code.
Why does rust use LLVM?
rustc uses LLVM to generate code. LLVM can generate very fast code, but it comes at a cost. LLVM is a very big system. The Rust compiler needs to keep up with LLVM releases though to avoid painful maintenance problems, so Rust builds are soon going to be pointlessly but unavoidably slower.
What does align 4 mean in LLVM?
The align 4 ensures that the address will be a multiple of 4 store i32 0, i32* %1. This sets the 32 bit integer pointed to by %1 to the 32 bit value 0.
Is Clang based on LLVM?
Clang is an “LLVM native” C/C++/Objective-C compiler, which aims to deliver amazingly fast compiles, extremely useful error and warning messages and to provide a platform for building great source level tools.
Why is LLVM bad?
The existence of LLVM is a terrible setback for our community precisely because it is not copylefted and can be used as the basis for nonfree compilers — so that all contribution to LLVM directly helps proprietary software as much as it helps us. The only code that helps us and not our adversaries is copylefted code.
Is Clang the best compiler?
Clang is a C, C++, Objective-C, or Objective-C++ compiler that is compiled in C++ based on LLVM and released under the Apache 2.0 license. Clang is mainly used to provide performance superior to that of GCC. Through long-term development and iteration, GCC, Clang, and LLVM have become mature compilers in the industry.